CN112310993A - Hybrid converter topology structure for forced current conversion and control method thereof - Google Patents

Hybrid converter topology structure for forced current conversion and control method thereof Download PDF

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CN112310993A
CN112310993A CN201910712265.7A CN201910712265A CN112310993A CN 112310993 A CN112310993 A CN 112310993A CN 201910712265 A CN201910712265 A CN 201910712265A CN 112310993 A CN112310993 A CN 112310993A
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bridge arm
auxiliary
circuit
valve
hybrid converter
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CN112310993B (en
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高冲
张娟娟
杨俊�
魏晓光
周建辉
盛财旺
李婷婷
张静
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State Grid Corp of China SGCC
Global Energy Interconnection Research Institute
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State Grid Corp of China SGCC
Global Energy Interconnection Research Institute
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    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J3/00—Circuit arrangements for ac mains or ac distribution networks
    • H02J3/36—Arrangements for transfer of electric power between ac networks via a high-tension dc link
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M1/00—Details of apparatus for conversion
    • H02M1/32—Means for protecting converters other than automatic disconnection
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/60—Arrangements for transfer of electric power between AC networks or generators via a high voltage DC link [HVCD]

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Abstract

The invention relates to a hybrid converter topological structure for forced current conversion and a control method thereof, wherein the topological structure comprises the following components: the three-phase six-bridge arm circuit comprises a three-phase six-bridge arm circuit and an auxiliary commutation circuit which is connected with the direct current side of the three-phase six-bridge arm circuit in parallel and has the capabilities of controllable turn-off of forward current and blocking of forward and reverse voltage; the auxiliary phase-changing circuit is respectively connected with the connecting points of the upper bridge arm and the lower bridge arm of each phase of bridge arm circuit in the three-phase six-bridge arm circuit through two-way valves with two-way opening and two-way pressure resistance on each phase of alternating current bus in the three-phase alternating current bus; according to the invention, the auxiliary phase-change circuit connected in parallel with the direct current side of the three-phase six-bridge arm circuit is added in the hybrid converter topological structure, so that the problem of the converter failure of the hybrid converter topological structure can be solved, and the technical scheme is simple to implement and low in cost.

Description

Hybrid converter topology structure for forced current conversion and control method thereof
Technical Field
The invention relates to the technical field of power electronics, in particular to a hybrid converter topological structure for forced current conversion and a control method thereof.
Background
The traditional power grid phase-change high voltage direct current (LCC-HVDC) power transmission system has the advantages of long-distance large-capacity power transmission, controllable active power and the like, and is widely applied in the world. However, because the thyristor adopted by the converter needs to provide phase-change voltage by depending on an alternating current system, phase-change failure is easy to occur under the conditions of alternating current system faults and the like, so that direct current is increased rapidly, and direct current transmission power is lost rapidly and greatly. In addition, in recent years, a plurality of direct current feeds are provided for a part of regional power grids, and once a certain circuit of direct current lines fails to change phase, the alternating current system coupling may cause the cascading failure of the multiple circuits of direct current lines, so as to bring more serious challenges to the safe and stable operation of the power grids.
Aiming at the problem of phase change failure of traditional direct current transmission, a lot of researchers have done a lot of research work, and invent various converter topological structures with the function of resisting the phase change failure, for example, one is a capacitor phase change converter topology (CCC), and the valve phase change voltage time area is increased through capacitor voltage to ensure the reliable turn-off of the converter topology; various topological structures are evolved based on the basic principle of a capacitance phase-changing circuit, and a controllable capacitance module is formed by combining a power electronic switch and a capacitor to realize capacitance input and voltage direction controllability; however, the above topology engineering based on capacitive commutation has a high difficulty. The other is that a turn-off device is connected with a thyristor in series to form a hybrid converter, so that each bridge arm of the converter has turn-off capability, and the occurrence of phase change failure is avoided; because the conventional direct-current transmission has large transmission capacity, each bridge arm of the converter bears high voltage and heavy current, the pipe valve capable of being turned off in the topology is realized in a multi-stage series-parallel connection mode, and meanwhile, the pipe valve capable of being turned off bears the heavy current for a long time, bears higher voltage stress when the heavy current is turned off, and needs more series stages, so the engineering realization cost and difficulty of the technical scheme are higher. In addition, in the prior art, a turn-off device is adopted to forcibly turn off the current to realize the transfer of the current, but the operation loss is increased due to the fact that the turn-off device conducts the current for a long time by buying the commutation technology, and cooling equipment needs to be additionally arranged, so that the realization cost of the technical scheme is higher.
Disclosure of Invention
Aiming at the defects of the prior art, the invention aims to provide a hybrid converter topological structure with forced commutation and a control method thereof.
The purpose of the invention is realized by adopting the following technical scheme:
the invention provides a hybrid converter topological structure for forced current conversion, and the improvement is that the topological structure comprises: the three-phase six-bridge arm circuit comprises a three-phase six-bridge arm circuit and an auxiliary commutation circuit which is connected with the direct current side of the three-phase six-bridge arm circuit in parallel and has the capabilities of controllable turn-off of forward current and blocking of forward and reverse voltage;
the auxiliary phase-changing circuit is respectively connected with the connection points of the upper bridge arm and the lower bridge arm of each phase of bridge arm circuit in the three-phase six-bridge arm circuit through two-way valves with two-way opening and two-way pressure resistance on each phase of alternating current bus in the three-phase alternating current bus.
Preferably, an upper bridge arm and a lower bridge arm of each phase of bridge arm circuit in the three-phase six-bridge arm circuit are both composed of a thyristor valve and a resonant commutation loop with capacitance unidirectional controllable discharge, which are connected in series.
Preferably, an upper bridge arm and a lower bridge arm of each phase of bridge arm circuit in the three-phase six-bridge arm circuit are composed of thyristor valves.
Furthermore, the auxiliary commutation circuit consists of an upper bridge arm auxiliary valve and a lower bridge arm auxiliary valve which are connected in series;
and the connection point between the upper bridge arm auxiliary valve and the lower bridge arm auxiliary valve is respectively connected with the connection point of the upper bridge arm and the lower bridge arm of each phase of bridge arm circuit in the three-phase six-bridge arm circuit through the two-way valve on each phase of alternating current bus in the three-phase alternating current bus.
Furthermore, the auxiliary commutation circuit is of a three-phase six-bridge arm structure;
each phase of bridge arm structure in the three-phase six-bridge arm structure consists of an upper bridge arm auxiliary valve and a lower bridge arm auxiliary valve which are connected in series;
and the connection points between the upper bridge arm auxiliary valve and the lower bridge arm auxiliary valve of each phase of bridge arm structure in the three-phase six-bridge arm structure are respectively connected with the connection points of the upper bridge arm and the lower bridge arm of each phase of bridge arm circuit in the three-phase six-bridge arm circuit through the two-way valve on each alternating current bus in the three-phase alternating current bus.
Furthermore, the auxiliary commutation circuit consists of an upper bridge arm auxiliary valve, an upper bridge arm resonant circuit, a lower bridge arm auxiliary valve and a lower bridge arm resonant circuit which are connected in series;
and the connection point between the upper bridge arm resonant circuit and the lower bridge arm auxiliary valve is respectively connected with the connection point of the upper bridge arm and the lower bridge arm of each phase of bridge arm circuit in the three-phase six-bridge arm circuit through the two-way valve on each phase of alternating current bus in the three-phase alternating current bus.
Furthermore, the auxiliary commutation circuit is of a three-phase six-bridge arm structure;
each phase of bridge arm structure in the three-phase six-bridge arm structure consists of an upper bridge arm auxiliary valve, an upper bridge arm resonant circuit, a lower bridge arm auxiliary valve and a lower bridge arm resonant circuit which are connected in series;
and the connection point between the upper bridge arm resonant circuit and the lower bridge arm auxiliary valve of each phase of bridge arm structure in the three-phase six-bridge arm structure is respectively connected with the connection point between the upper bridge arm and the lower bridge arm of each phase of bridge arm circuit in the three-phase six-bridge arm circuit through the two-way valve on each alternating current bus in the three-phase alternating current bus.
Further, the thyristor valve is composed of a plurality of thyristors and a buffer component connected in series or in parallel with each thyristor of the plurality of thyristors.
Further, the resonant tank includes: the device comprises an inductor and a discharge branch circuit connected with the inductor in parallel.
Furthermore, the discharge branch consists of a pre-charge capacitor and a discharge time sequence control circuit which are connected in series;
the discharge time sequence control circuit is composed of a plurality of controllable power electronic devices connected in series in the forward direction and a buffer component connected with the plurality of controllable electronic devices connected in series or in parallel.
Further, the discharging branch consists of a pre-charging capacitor and a control branch which are connected in series;
the control branch circuit consists of a first discharge time sequence control circuit and a second discharge time sequence control circuit which is reversely connected with the first discharge time sequence control circuit in parallel;
the first discharge time sequence control circuit and the second discharge time sequence control circuit are respectively composed of a plurality of controllable power electronic devices which are connected in series in the forward direction and a buffer component which is connected with the plurality of controllable electronic devices which are connected in series in the forward direction or in parallel.
Furthermore, the discharge branch consists of a first control branch, a pre-charge capacitor and a second control branch which are connected in parallel;
the first control branch circuit and the second control branch circuit are respectively composed of two groups of discharge time sequence control circuits which are connected in series in the forward direction;
the connection points of the two groups of discharge time sequence control circuits of the first control branch circuit and the second control branch circuit are connected with the two ends of the inductor;
the discharge time sequence control circuit is composed of a plurality of controllable power electronic devices which are connected in series in the forward direction and a buffer component which is connected with the plurality of controllable electronic devices which are connected in series in the forward direction or in parallel.
Furthermore, the upper bridge arm auxiliary valve and the lower bridge arm auxiliary valve are both composed of a plurality of auxiliary sub-modules connected in series and buffer components respectively connected in series or in parallel with each of the plurality of auxiliary sub-modules connected in series;
the auxiliary sub-module is composed of one or more of fully-controlled power electronic devices with reverse voltage blocking capability, or is composed of fully-controlled power electronic devices without reverse voltage blocking capability, diodes in reverse parallel connection with the fully-controlled power electronic devices without reverse voltage blocking capability, and buffer components in series connection or parallel connection with the fully-controlled power electronic devices without reverse voltage blocking capability.
Furthermore, the upper bridge arm auxiliary valve and the lower bridge arm auxiliary valve are respectively composed of a first auxiliary branch, a buffer part and a second auxiliary branch which are connected in parallel;
the first auxiliary branch and the second auxiliary branch are composed of two groups of auxiliary sequential control branches which are connected in series in the forward direction;
the auxiliary time sequence control circuit consists of a plurality of auxiliary sub-modules which are connected in series and buffer components which are respectively connected with each auxiliary sub-module in the plurality of auxiliary sub-modules in series or in parallel;
the auxiliary sub-module is composed of one or more of fully-controlled power electronic devices with reverse voltage blocking capability, or is composed of fully-controlled power electronic devices without reverse voltage blocking capability, diodes in reverse parallel connection with the fully-controlled power electronic devices without reverse voltage blocking capability and buffer components in series connection or parallel connection with the fully-controlled power electronic devices without reverse voltage blocking capability;
the external connection point of the first auxiliary branch and the external connection point of the second auxiliary branch are respectively connection points of two groups of auxiliary time sequence control branches of the first auxiliary branch and the second auxiliary branch.
Furthermore, the upper bridge arm auxiliary valve and the lower bridge arm auxiliary valve are respectively provided with a first diode branch, an auxiliary branch and a second diode branch which are connected in parallel;
the first diode branch circuit and the second diode branch circuit are respectively composed of two groups of diode time sequence control branch circuits which are connected in series in the forward direction;
the auxiliary branch circuit consists of a plurality of auxiliary sub-modules which are connected in series and buffer components which are respectively connected with each auxiliary sub-module in the plurality of auxiliary sub-modules which are connected in series or in parallel;
the auxiliary sub-module is composed of one or more of fully-controlled power electronic devices with reverse voltage blocking capability, or is composed of fully-controlled power electronic devices without reverse voltage blocking capability, diodes in reverse parallel connection with the fully-controlled power electronic devices without reverse voltage blocking capability and buffer components in series connection or parallel connection with the fully-controlled power electronic devices without reverse voltage blocking capability;
the external connection point of the first diode branch and the external connection point of the second diode branch are respectively connection points of two groups of diode time sequence control branches of the first diode branch and the second diode branch.
Furthermore, the upper bridge arm auxiliary valve and the lower bridge arm auxiliary valve are respectively a third auxiliary branch and a fourth auxiliary branch which is reversely connected with the third auxiliary branch in parallel;
the third auxiliary branch is composed of a plurality of auxiliary sub-modules connected in series and buffer components connected in series or in parallel with each auxiliary sub-module in the plurality of auxiliary sub-modules connected in series respectively;
the fourth auxiliary branch consists of a capacitor connected in series, a plurality of auxiliary sub-modules connected in series and a buffer component connected in series or in parallel with each of the plurality of auxiliary sub-modules connected in series;
the auxiliary sub-module is composed of one or more of fully-controlled power electronic devices with reverse voltage blocking capability, or is composed of fully-controlled power electronic devices without reverse voltage blocking capability, diodes in reverse parallel connection with the fully-controlled power electronic devices without reverse voltage blocking capability, and buffer components in series connection or parallel connection with the fully-controlled power electronic devices without reverse voltage blocking capability.
Furthermore, the bidirectional valve consists of a first thyristor branch and a second thyristor branch which is connected with the first thyristor branch in inverse parallel;
the first thyristor branch circuit and the second thyristor branch circuit are both composed of a plurality of thyristor modules connected in series;
the thyristor module consists of a thyristor and a buffer component connected with the thyristor in series or in parallel.
Preferably, the two-way valve consists of a first two-way valve branch and a second two-way valve branch which is connected with the first two-way valve branch in an anti-parallel mode;
the first bidirectional valve branch and the second bidirectional valve branch are both composed of a first bidirectional valve timing control branch and a second bidirectional valve timing control branch which is reversely connected with the first bidirectional valve timing control branch in series;
the first two-way valve timing sequence control branch circuit and the second two-way valve timing sequence control branch circuit are respectively composed of a plurality of auxiliary sub-modules which are connected in series and buffer parts which are respectively connected with each auxiliary sub-module in the plurality of auxiliary sub-modules which are connected in series or in parallel;
the auxiliary sub-module is composed of one or more of fully-controlled power electronic devices with reverse voltage blocking capability, or is composed of fully-controlled power electronic devices without reverse voltage blocking capability, diodes in reverse parallel connection with the fully-controlled power electronic devices without reverse voltage blocking capability, and buffer components in series connection or parallel connection with the fully-controlled power electronic devices without reverse voltage blocking capability.
Preferably, the two-way valve consists of a third, auxiliary and fourth two-way valve branch connected in parallel;
the third two-way valve branch and the fourth two-way valve branch are both composed of two-way valve timing control branches which are connected in series in the forward direction;
the two-way valve time sequence control circuits are composed of a plurality of diodes which are connected in series in the forward direction and a plurality of buffer components which are connected in series or in parallel respectively;
the auxiliary branch circuit consists of a plurality of auxiliary sub-modules which are connected in series and buffer components which are respectively connected with each auxiliary sub-module in the plurality of auxiliary sub-modules which are connected in series or in parallel;
the auxiliary sub-module is composed of one or more of fully-controlled power electronic devices with reverse voltage blocking capability, or is composed of fully-controlled power electronic devices without reverse voltage blocking capability, diodes in reverse parallel connection with the fully-controlled power electronic devices without reverse voltage blocking capability and buffer components in series connection or parallel connection with the fully-controlled power electronic devices without reverse voltage blocking capability;
the external connection point of the third two-way valve branch and the external connection point of the fourth two-way valve branch are respectively the connection point of the two diode time sequence control branches of the third two-way valve branch and the connection point of the two diode time sequence control branches of the fourth two-way valve branch.
Further, the buffer component is composed of one or more of a capacitor, a resistance-capacitance loop, a diode, an inductor or an arrester which are connected in series or in parallel.
Based on the same inventive concept, the invention also provides a control method of the topological structure, and the improvement is that the method comprises the following steps:
turning off an auxiliary valve of an auxiliary phase change circuit connected with the ith bridge arm in the topological structure of the hybrid converter, and executing the following steps;
step 11, conducting a thyristor valve of the ith bridge arm in the topological structure of the hybrid converter, and executing step 12;
step 12, after a control period T, returning to the step 11;
wherein i ∈ [1,6 ].
Preferably, when at tfWhen detecting that the ith bridge arm in the topological structure of the hybrid converter has phase change failure or short-circuit fault at any moment, at tfA bidirectional valve connected with the ith bridge arm in the topological structure of the constantly conducted hybrid converter is at tfAn auxiliary valve of an auxiliary phase change circuit connected with the ith bridge arm in the topological structure of the time-conduction hybrid converter is at tqConstantly conducting a resonant circuit of the ith bridge arm in the hybrid converter topology or a resonant circuit of an auxiliary phase change circuit connected with the ith bridge arm in the hybrid converter topology, and when a thyristor valve of the ith bridge arm in the hybrid converter topology is in a forward blocking state, the hybrid converter topologyIn the structure, a bidirectional valve connected with the ith bridge arm is forced to be turned off, and when a resonant circuit of the ith bridge arm in the topological structure of the hybrid converter or a resonant circuit of an auxiliary phase change circuit connected with the ith bridge arm in the topological structure of the hybrid converter is turned off, an auxiliary valve of the auxiliary phase change circuit connected with the ith bridge arm is turned off, and when t isfExecuting step S11 when the control cycle is over, turning off an auxiliary valve of an auxiliary phase change circuit connected with the ith bridge arm in the hybrid converter topology structure until the voltage of the hybrid converter topology structure is recovered to be stable, and executing step 11; s11, switching on a thyristor valve of the ith bridge arm in the topological structure of the hybrid converter, switching off an auxiliary valve of an auxiliary phase change circuit connected with the ith bridge arm in the topological structure of the hybrid converter, and enabling the auxiliary valve to pass through
Figure BDA0002154175920000061
Thereafter, step S12 is executed;
s12, conducting a two-way valve connected with the ith bridge arm in the topological structure of the hybrid converter, and conducting an auxiliary valve of an auxiliary phase change circuit connected with the ith bridge arm in the topological structure of the hybrid converter
Figure BDA0002154175920000062
Switching on a resonant circuit of the ith bridge arm in the hybrid converter topology or a resonant circuit of an auxiliary phase change circuit connected with the ith bridge arm in the hybrid converter topology at any time, and executing the step S13 when a thyristor valve of the ith bridge arm in the hybrid converter topology is in a forward blocking state, a two-way valve connected with the ith bridge arm in the hybrid converter topology is forcibly switched off, and the resonant circuit of the ith bridge arm in the hybrid converter topology or the resonant circuit of the auxiliary phase change circuit connected with the ith bridge arm in the hybrid converter topology is switched off;
step S13, turning off an auxiliary valve of an auxiliary phase change circuit connected with the ith bridge arm in the topology structure of the hybrid converter, and enabling the auxiliary valve to pass through delta t'offThen, the process returns to step S11;
wherein, tf＜tq，Δt'offIn order to execute the time length of the thyristor valve of the ith bridge arm in the hybrid converter topology in the control period from the step S11 to the step S13, delta t1T is a control period for conducting the delay time of the resonant circuit of the ith bridge arm in the topological structure of the hybrid converter or the resonant circuit of the auxiliary phase change circuit connected with the ith bridge arm in the topological structure of the hybrid converter.
Based on the same inventive concept, the invention also provides a control method of the topological structure, and the improvement is that the method comprises the following steps:
s21, switching on a thyristor valve of the ith bridge arm in the topological structure of the hybrid converter, switching off an auxiliary valve of an auxiliary phase change circuit connected with the ith bridge arm in the topological structure of the hybrid converter, and enabling the auxiliary valve to pass through
Figure BDA0002154175920000063
Thereafter, step S22 is executed;
s22, conducting a two-way valve connected with the ith bridge arm in the topological structure of the hybrid converter, and conducting an auxiliary valve of an auxiliary phase change circuit connected with the ith bridge arm in the topological structure of the hybrid converter
Figure BDA0002154175920000071
Switching on a resonant circuit of the ith bridge arm in the hybrid converter topology or a resonant circuit of an auxiliary phase change circuit connected with the ith bridge arm in the hybrid converter topology at any time, and executing the step S23 when a thyristor valve of the ith bridge arm in the hybrid converter topology is in a forward blocking state, a two-way valve connected with the ith bridge arm in the hybrid converter topology is forcibly switched off, and the resonant circuit of the ith bridge arm in the hybrid converter topology or the resonant circuit of the auxiliary phase change circuit connected with the ith bridge arm in the hybrid converter topology is switched off;
s23, turning off an auxiliary valve of an auxiliary phase change circuit connected with the ith bridge arm in the topological structure of the hybrid converter, and enabling the auxiliary valve to pass through delta t'offThen, the process returns to step S21;
wherein, Deltat”offIn order to execute the time length of the thyristor valve of the ith bridge arm in the hybrid converter topology in the control period from the step S21 to the step S23, delta t1In order to conduct the delay time of the resonant circuit of the ith bridge arm in the topological structure of the hybrid converter or the resonant circuit of the auxiliary phase change circuit connected with the ith bridge arm in the topological structure of the hybrid converter, T is a control period, i belongs to [1,6]]。
Based on the same inventive concept, the invention also provides a control method of the topological structure, and the improvement is that the method comprises the following steps:
turning off an auxiliary valve of an auxiliary phase change circuit connected with the ith bridge arm in the topological structure of the hybrid converter, and turning off a two-way valve connected with the ith bridge arm in the topological structure of the hybrid converter, and executing the following steps;
step 21, conducting a thyristor valve of the ith bridge arm in the topological structure of the hybrid converter, and executing the step 22;
step 22, after a control period T, returning to the step 21;
wherein i ∈ [1,6 ].
Preferably, when at tfWhen detecting that the ith bridge arm in the topological structure of the hybrid converter has phase change failure or short-circuit fault at any moment, at tfA bidirectional valve connected with the ith bridge arm in the topological structure of the constantly conducted hybrid converter is at tfAn auxiliary valve of an auxiliary phase change circuit connected with the ith bridge arm in the topological structure of the time-conduction hybrid converter is at tqThe method comprises the steps of conducting a resonant circuit of the ith bridge arm in a hybrid converter topological structure or a resonant circuit of an auxiliary phase change circuit connected with the ith bridge arm in the hybrid converter topological structure at any time, when a thyristor valve of the ith bridge arm is in a forward blocking state, and the resonant circuit of the ith bridge arm in the hybrid converter topological structure or the resonant circuit of the auxiliary phase change circuit connected with the ith bridge arm in the hybrid converter topological structure is turned off, turning off a two-way valve connected with the ith bridge arm in the hybrid converter topological structure, turning off the auxiliary valve of the auxiliary phase change circuit connected with the ith bridge arm, and when t isfControl ofExecuting step T11 when the period is over, turning off an auxiliary valve of an auxiliary phase change circuit connected with the ith bridge arm in the hybrid converter topology structure and turning off a bidirectional valve connected with the ith bridge arm in the hybrid converter topology structure when the voltage of the hybrid converter topology structure is recovered to be stable, and executing step 21;
and step T11, switching on a thyristor valve of the ith bridge arm in the topological structure of the hybrid converter, switching off an auxiliary valve of an auxiliary phase change circuit connected with the ith bridge arm in the topological structure of the hybrid converter, and switching off a two-way valve connected with the ith bridge arm in the topological structure of the hybrid converter, wherein the two-way valve passes through
Figure BDA0002154175920000081
Thereafter, step T12 is executed;
and T12, conducting a two-way valve connected with the ith bridge arm in the topological structure of the hybrid converter, and conducting an auxiliary valve of an auxiliary phase change circuit connected with the ith bridge arm in the topological structure of the hybrid converter
Figure BDA0002154175920000082
Switching on a resonant circuit of the ith bridge arm in the hybrid converter topology or a resonant circuit of an auxiliary phase change circuit connected with the ith bridge arm in the hybrid converter topology at any time, and executing the step T13 when a thyristor valve of the ith bridge arm in the hybrid converter topology is in a forward blocking state and the resonant circuit of the ith bridge arm in the hybrid converter topology or the resonant circuit of the auxiliary phase change circuit connected with the ith bridge arm in the hybrid converter topology is switched off;
step T13, turning off a two-way valve connected with the ith arm in the topology structure of the hybrid converter, and turning off an auxiliary valve of an auxiliary phase change circuit connected with the ith arm in the topology structure of the hybrid converter, wherein the two-way valve passes through delta T'offThen, returning to the step T11;
wherein, tf＜tq，ΔT’offThe thyristor valve of the ith arm in the hybrid converter topology is in a forward blocking state in order to execute the control period from step T11 to step T13Duration of state, Δ t1T is a control period for conducting the delay time of the resonant circuit of the ith bridge arm in the topological structure of the hybrid converter or the resonant circuit of the auxiliary phase change circuit connected with the ith bridge arm in the topological structure of the hybrid converter.
Based on the same inventive concept, the invention also provides a control method of the topological structure, and the improvement is that the method comprises the following steps:
and T21, switching on a thyristor valve of the ith bridge arm in the topological structure of the hybrid converter, switching off an auxiliary valve of an auxiliary phase change circuit connected with the ith bridge arm in the topological structure of the hybrid converter, and switching off a two-way valve connected with the ith bridge arm in the topological structure of the hybrid converter, wherein the two-way valve passes through
Figure BDA0002154175920000083
Thereafter, step T22 is executed;
step T22, conducting a two-way valve connected with the ith bridge arm in the topological structure of the hybrid converter, conducting an auxiliary valve of an auxiliary phase change circuit connected with the ith bridge arm in the topological structure of the hybrid converter, and switching on the auxiliary valve
Figure BDA0002154175920000084
Switching on a resonant circuit of the ith bridge arm in the hybrid converter topology or a resonant circuit of an auxiliary phase change circuit connected with the ith bridge arm in the hybrid converter topology at any time, and executing the step T23 when a thyristor valve of the ith bridge arm in the hybrid converter topology is in a forward blocking state and the resonant circuit of the ith bridge arm in the hybrid converter topology or the resonant circuit of the auxiliary phase change circuit connected with the ith bridge arm in the hybrid converter topology is switched off;
and T23, turning off a two-way valve connected with the ith bridge arm in the topological structure of the hybrid converter, and turning off an auxiliary valve of an auxiliary phase change circuit connected with the ith bridge arm in the topological structure of the hybrid converter, wherein the two-way valve passes through delta T'offThen, returning to the step T21;
wherein, Delta T "offOne control period internal mixing for executing the steps T21 to T23The time length delta t of the thyristor valve of the ith bridge arm in the topological structure of the combined converter in the forward blocking state1In order to conduct the delay time of the resonant circuit of the ith bridge arm in the topological structure of the hybrid converter or the resonant circuit of the auxiliary phase change circuit connected with the ith bridge arm in the topological structure of the hybrid converter, T is a control period, i belongs to [1,6]]。
To sum up, the present invention relates to a hybrid converter topology for forced current conversion and a control method thereof, including: the three-phase six-bridge arm circuit comprises a three-phase six-bridge arm circuit and an auxiliary commutation circuit which is connected with the direct current side of the three-phase six-bridge arm circuit in parallel and has the capabilities of controllable turn-off of forward current and blocking of forward and reverse voltage; the auxiliary phase-changing circuit is respectively connected with the connection points of the upper bridge arm and the lower bridge arm of each phase of bridge arm circuit in the three-phase six-bridge arm circuit through the two-way valves on the alternating current buses in the three-phase alternating current buses; according to the invention, through the added auxiliary phase change circuit, when the phase change of the converter fails, the phase change current can be transferred and the phase change time can be flexibly controlled, and the phase change between two bridge arms can be quickly recovered by utilizing the high-current turn-off characteristic of a turn-off device, so that the recovery time of the converter after the phase change fails is greatly accelerated; according to the resonant circuit introduced by the main bridge arm, the current generated on the inductor during discharging counteracts the current of the thyristor valve, the valve current is forcibly transferred to the auxiliary valve, and commutation is carried out between the auxiliary valve and the next bridge arm; according to the bidirectional valve, a transfer path of current of the main bridge arm to the auxiliary phase change circuit is provided during failure, and the upper bridge arm and the lower bridge arm of each phase are respectively changed to the auxiliary phase change circuit by controlling the opening direction of the bidirectional valve; when the hybrid converter topological structure adopts the alternate operation control method, the occurrence of short-circuit current and commutation failure can be avoided, and the overall reliability of the converter is improved.
Drawings
Fig. 1 is a schematic diagram of a hybrid converter topology according to a first embodiment of the present invention;
fig. 2 is a schematic diagram of a hybrid converter topology according to a second embodiment of the present invention;
fig. 3 is a schematic diagram of a hybrid converter topology according to a third embodiment of the present invention;
fig. 4 is a schematic diagram of a hybrid converter topology according to a fourth embodiment of the present invention;
fig. 5 is a schematic structural diagram of a resonant tank of a hybrid inverter topology according to the first to fourth embodiments of the present invention;
fig. 6 is a schematic diagram of an auxiliary valve structure of a hybrid converter topology according to the first to fourth embodiments of the present invention;
fig. 7 is a schematic diagram of a bidirectional valve structure of a hybrid converter topology according to the first to fourth embodiments of the present invention;
fig. 8 is a structural diagram of a buffering component of a hybrid converter topology according to the first to fourth embodiments of the present invention;
fig. 9 is a first control timing diagram of a hybrid converter topology according to the first to fourth embodiments of the present invention;
fig. 10 is a second control timing diagram of the hybrid converter topology according to the first to fourth embodiments of the present invention;
fig. 11 is a current flow path when the hybrid converter topology according to the first to fourth embodiments of the present invention fails.
Detailed Description
The following describes embodiments of the present invention in further detail with reference to the accompanying drawings.
In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are some, but not all, embodiments of the present invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
The invention provides a hybrid converter topological structure for forced current conversion, which comprises: the three-phase six-bridge arm circuit comprises a three-phase six-bridge arm circuit and an auxiliary commutation circuit which is connected with the direct current side of the three-phase six-bridge arm circuit in parallel and has the capabilities of controllable turn-off of forward current and blocking of forward and reverse voltage;
the auxiliary phase-changing circuit is respectively connected with the connection points of the upper bridge arm and the lower bridge arm of each phase of bridge arm circuit in the three-phase six-bridge arm circuit through two-way valves with two-way opening and two-way pressure resistance on each phase of alternating current bus in the three-phase alternating current bus.
In the first and second embodiments of the present invention, as shown in fig. 1 and 2, the upper arm and the lower arm of each phase of arm circuit in the three-phase six-arm circuit are composed of a thyristor valve and a resonant tank connected in series.
As shown in fig. 1, the auxiliary commutation circuit is composed of an upper bridge arm auxiliary valve and a lower bridge arm auxiliary valve which are connected in series;
and the connection point between the upper bridge arm auxiliary valve and the lower bridge arm auxiliary valve is respectively connected with the connection point of the upper bridge arm and the lower bridge arm of each phase of bridge arm circuit in the three-phase six-bridge arm circuit through the two-way valve on each phase of alternating current bus in the three-phase alternating current bus.
As shown in fig. 2, the auxiliary commutation circuit has a three-phase six-leg structure;
each phase of bridge arm structure in the three-phase six-bridge arm structure consists of an upper bridge arm auxiliary valve and a lower bridge arm auxiliary valve which are connected in series;
and the connection points between the upper bridge arm auxiliary valve and the lower bridge arm auxiliary valve of each phase of bridge arm structure in the three-phase six-bridge arm structure are respectively connected with the connection points of the upper bridge arm and the lower bridge arm of each phase of bridge arm circuit in the three-phase six-bridge arm circuit through the two-way valve on each alternating current bus in the three-phase alternating current bus.
In the third and fourth embodiments of the present invention, as shown in fig. 3 and 4, the upper arm and the lower arm of each phase arm circuit in the three-phase six-arm circuit described above are each composed of a thyristor valve.
As shown in fig. 3, the auxiliary phase-changing circuit is composed of an upper bridge arm auxiliary valve, an upper bridge arm resonant circuit, a lower bridge arm auxiliary valve and a lower bridge arm resonant circuit which are connected in series;
and the connection point between the upper bridge arm resonant circuit and the lower bridge arm auxiliary valve is respectively connected with the connection point of the upper bridge arm and the lower bridge arm of each phase of bridge arm circuit in the three-phase six-bridge arm circuit through the two-way valve on each phase of alternating current bus in the three-phase alternating current bus.
As shown in fig. 4, the auxiliary commutation circuit has a three-phase six-leg structure;
each phase of bridge arm structure in the three-phase six-bridge arm structure consists of an upper bridge arm auxiliary valve, an upper bridge arm resonant circuit, a lower bridge arm auxiliary valve and a lower bridge arm resonant circuit which are connected in series;
and the connection point between the upper bridge arm resonant circuit and the lower bridge arm auxiliary valve of each phase of bridge arm structure in the three-phase six-bridge arm structure is respectively connected with the connection point between the upper bridge arm and the lower bridge arm of each phase of bridge arm circuit in the three-phase six-bridge arm circuit through the two-way valve on each alternating current bus in the three-phase alternating current bus.
The skilled person will appreciate that the cathode of the upper bridge arm auxiliary valve is connected to the positive dc voltage p, the anode of the upper bridge arm auxiliary valve is connected to the cathode of the lower bridge arm auxiliary valve, and the anode of the lower bridge arm auxiliary valve is connected to the negative dc voltage q.
Wherein Cg 1-Cg 6 in FIG. 1 are resonance circuits, DVa, DVb and DVc two-way valves, Vp and Vq are auxiliary valves;
cg 1-Cg 6 in fig. 2 are resonant circuits, DVa, DVb, DVc two-way valves, Vpa, Vqa, Vpb, Vqb, Vpc, Vqc are auxiliary valves;
in the DVa, DVb and DVc two-way valve of FIG. 3, Vp and Vq are auxiliary valves, Cp and Cq are resonant loops;
in the DVa, DVb and DVc bidirectional valves of fig. 4, Vpa, Vqa, VPb, Vqb, Vpc and Vqc are auxiliary valves, and Cpa, Cqa, Cpb, Cqb, Cpc and Cqc are resonant circuits.
The thyristor valve consists of a plurality of thyristors and a buffer component which is connected in series or in parallel with each thyristor in the plurality of thyristors.
The resonant tank includes: the device comprises an inductor and a discharge branch circuit connected with the inductor in parallel. Those skilled in the art will appreciate that the inductor may be replaced with a transformer.
As shown in fig. 5 (a), the discharging branch circuit is composed of a pre-charging capacitor and a discharging timing control circuit connected in series;
the discharge time sequence control circuit is composed of a plurality of controllable power electronic devices connected in series in the forward direction and a buffer component connected with the plurality of controllable electronic devices connected in series or in parallel.
As shown in fig. 5 (b), the discharging branch consists of a pre-charging capacitor and a control branch connected in series;
the control branch circuit consists of a first discharge time sequence control circuit and a second discharge time sequence control circuit which is reversely connected with the first discharge time sequence control circuit in parallel;
the first discharge time sequence control circuit and the second discharge time sequence control circuit are respectively composed of a plurality of controllable power electronic devices which are connected in series in the forward direction and a buffer component which is connected with the plurality of controllable electronic devices which are connected in series in the forward direction or in parallel.
As shown in fig. 5 (c), the discharging branch consists of a first control branch, a pre-charging capacitor and a second control branch which are connected in parallel;
the first control branch circuit and the second control branch circuit are respectively composed of two groups of discharge time sequence control circuits which are connected in series in the forward direction;
the connection points of the two groups of discharge time sequence control circuits of the first control branch circuit and the second control branch circuit are connected with the two ends of the inductor;
the discharge time sequence control circuit is composed of a plurality of controllable power electronic devices which are connected in series in the forward direction and a buffer component which is connected with the plurality of controllable electronic devices which are connected in series in the forward direction or in parallel.
Furthermore, the reverse-resistance type full-control power electronic device in the invention is a full-control power electronic device with reverse voltage blocking capability, so that the reverse-resistance type full-control power electronic device in the auxiliary sub-module does not need an anti-parallel diode; the fully-controlled power electronic devices except the reverse-resistance type are fully-controlled power electronic devices without reverse voltage capability, so that the fully-controlled power electronic devices except the reverse-resistance type in the auxiliary sub-module need anti-parallel diodes.
As shown in fig. 6 (a), each of the upper bridge arm auxiliary valve and the lower bridge arm auxiliary valve is composed of a plurality of auxiliary sub-modules connected in series and a buffer component connected in series or in parallel with each of the plurality of auxiliary sub-modules connected in series;
the auxiliary sub-module is composed of one or more of fully-controlled power electronic devices with reverse voltage blocking capability, or is composed of fully-controlled power electronic devices without reverse voltage blocking capability, diodes in reverse parallel connection with the fully-controlled power electronic devices without reverse voltage blocking capability, and buffer components in series connection or parallel connection with the fully-controlled power electronic devices without reverse voltage blocking capability.
As shown in fig. 6 (b), the upper arm auxiliary valve and the lower arm auxiliary valve are each composed of a first auxiliary branch, a buffer member, and a second auxiliary branch connected in parallel;
the first auxiliary branch and the second auxiliary branch are composed of two groups of auxiliary sequential control branches which are connected in series in the forward direction;
the auxiliary time sequence control circuit consists of a plurality of auxiliary sub-modules which are connected in series and buffer components which are respectively connected with each auxiliary sub-module in the plurality of auxiliary sub-modules in series or in parallel;
the auxiliary sub-module is composed of one or more of fully-controlled power electronic devices with reverse voltage blocking capability, or is composed of fully-controlled power electronic devices without reverse voltage blocking capability, diodes in reverse parallel connection with the fully-controlled power electronic devices without reverse voltage blocking capability and buffer components in series connection or parallel connection with the fully-controlled power electronic devices without reverse voltage blocking capability;
the external connection point of the first auxiliary branch and the external connection point of the second auxiliary branch are respectively connection points of two groups of auxiliary time sequence control branches of the first auxiliary branch and the second auxiliary branch.
As shown in fig. 6 (c), the upper arm auxiliary valve and the lower arm auxiliary valve are each formed by a first diode branch, an auxiliary branch, and a second diode branch connected in parallel;
the first diode branch circuit and the second diode branch circuit are respectively composed of two groups of diode time sequence control branch circuits which are connected in series in the forward direction;
the auxiliary branch circuit consists of a plurality of auxiliary sub-modules which are connected in series and buffer components which are respectively connected with each auxiliary sub-module in the plurality of auxiliary sub-modules which are connected in series or in parallel;
the auxiliary sub-module is composed of one or more of fully-controlled power electronic devices with reverse voltage blocking capability, or is composed of fully-controlled power electronic devices without reverse voltage blocking capability, diodes in reverse parallel connection with the fully-controlled power electronic devices without reverse voltage blocking capability and buffer components in series connection or parallel connection with the fully-controlled power electronic devices without reverse voltage blocking capability;
the external connection point of the first diode branch and the external connection point of the second diode branch are respectively connection points of two groups of diode time sequence control branches of the first diode branch and the second diode branch.
As shown in fig. 6 (d), each of the upper arm assist valve and the lower arm assist valve includes a third assist branch and a fourth assist branch connected in reverse parallel with the third assist branch;
the third auxiliary branch is composed of a plurality of auxiliary sub-modules connected in series and buffer components connected in series or in parallel with each auxiliary sub-module in the plurality of auxiliary sub-modules connected in series respectively;
the fourth auxiliary branch consists of a capacitor connected in series, a plurality of auxiliary sub-modules connected in series and a buffer component connected in series or in parallel with each of the plurality of auxiliary sub-modules connected in series;
the auxiliary sub-module is composed of one or more of fully-controlled power electronic devices with reverse voltage blocking capability, or is composed of fully-controlled power electronic devices without reverse voltage blocking capability, diodes in reverse parallel connection with the fully-controlled power electronic devices without reverse voltage blocking capability, and buffer components in series connection or parallel connection with the fully-controlled power electronic devices without reverse voltage blocking capability.
As shown in fig. 7 (a), the bidirectional valve is composed of a first thyristor branch and a second thyristor branch connected in anti-parallel therewith;
the first thyristor branch circuit and the second thyristor branch circuit are both composed of a plurality of thyristor modules connected in series;
the thyristor module consists of a thyristor and a buffer component connected with the thyristor in series or in parallel.
As shown in fig. 7 (b), the bidirectional valve is composed of a first bidirectional valve branch and a second bidirectional valve branch connected in reverse parallel with the first bidirectional valve branch;
the first bidirectional valve branch and the second bidirectional valve branch are both composed of a first bidirectional valve timing control branch and a second bidirectional valve timing control branch which is reversely connected with the first bidirectional valve timing control branch in series;
the first two-way valve timing sequence control branch circuit and the second two-way valve timing sequence control branch circuit are respectively composed of a plurality of auxiliary sub-modules which are connected in series and buffer parts which are respectively connected with each auxiliary sub-module in the plurality of auxiliary sub-modules which are connected in series or in parallel;
the auxiliary sub-module is composed of one or more of fully-controlled power electronic devices with reverse voltage blocking capability, or is composed of fully-controlled power electronic devices without reverse voltage blocking capability, diodes in reverse parallel connection with the fully-controlled power electronic devices without reverse voltage blocking capability, and buffer components in series connection or parallel connection with the fully-controlled power electronic devices without reverse voltage blocking capability.
As shown in fig. 7 (c), the above-mentioned two-way valve consists of a third two-way valve branch, an auxiliary branch and a fourth two-way valve branch connected in parallel;
the third two-way valve branch and the fourth two-way valve branch are both composed of two-way valve timing control branches which are connected in series in the forward direction;
the two-way valve time sequence control circuits are composed of a plurality of diodes which are connected in series in the forward direction and a plurality of buffer components which are connected in series or in parallel respectively;
the auxiliary branch circuit consists of a plurality of auxiliary sub-modules which are connected in series and buffer components which are respectively connected with each auxiliary sub-module in the plurality of auxiliary sub-modules which are connected in series or in parallel;
the auxiliary sub-module is composed of one or more of fully-controlled power electronic devices with reverse voltage blocking capability, or is composed of fully-controlled power electronic devices without reverse voltage blocking capability, diodes in reverse parallel connection with the fully-controlled power electronic devices without reverse voltage blocking capability and buffer components in series connection or parallel connection with the fully-controlled power electronic devices without reverse voltage blocking capability;
the external connection point of the third two-way valve branch and the external connection point of the fourth two-way valve branch are respectively the connection point of the two diode time sequence control branches of the third two-way valve branch and the connection point of the two diode time sequence control branches of the fourth two-way valve branch.
As shown in fig. 8, the buffer component is composed of one or more of a capacitor, a resistance-capacitance loop, a diode, an inductor or an arrester connected in series or in parallel.
The fully-controlled power electronic device is composed of one or more of IGBT, IGCT, IEGT, GTO or MOSFET turn-off devices, and the controllable power electronic device is a thyristor.
In fig. 9, Sg1 is a control timing of the thyristor valve, Sg12 is a control timing of the resonant circuit, Sga1 is a control timing of the bidirectional valve, Sap is a control timing of the auxiliary valve, and t is0The control period T is 2 pi for the initial trigger time.
Based on the same inventive concept, the invention also provides a control method of the topological structure, which comprises the following steps:
turning off an auxiliary valve of an auxiliary phase change circuit connected with the ith bridge arm in the topological structure of the hybrid converter, and executing the following steps;
step 11, conducting a thyristor valve of the ith bridge arm in the topological structure of the hybrid converter, and executing step 12;
step 12, after a control period T, returning to the step 11;
wherein i ∈ [1,6 ].
As shown in (a) of FIG. 9The two-way valve comprises a thyristor, is a non-turn-off device, and is a path through which valve current flows during normal phase change, the main branch is periodically subjected to voltage and current stress, the auxiliary valve is always in a turn-off state, the resonant circuit is not conducted, and when the auxiliary valve is in a turn-off state at tfWhen detecting that the ith bridge arm in the topological structure of the hybrid converter has phase change failure or short-circuit fault at any moment, at tfA bidirectional valve connected with the ith bridge arm in the topological structure of the constantly conducted hybrid converter is at tfAn auxiliary valve of an auxiliary phase change circuit connected with the ith bridge arm in the topological structure of the time-conduction hybrid converter is at tqThe method comprises the steps of conducting a resonant circuit of the ith bridge arm in a hybrid converter topological structure or a resonant circuit of an auxiliary phase change circuit connected with the ith bridge arm in the hybrid converter topological structure at any time, when a thyristor valve of the ith bridge arm in the hybrid converter topological structure is in a forward blocking state, a two-way valve connected with the ith bridge arm in the hybrid converter topological structure is forced to be turned off, and the resonant circuit of the ith bridge arm in the hybrid converter topological structure or the resonant circuit of the auxiliary phase change circuit connected with the ith bridge arm in the hybrid converter topological structure is turned off, turning off the auxiliary valve of the auxiliary phase change circuit connected with the ith bridge arm, and when t isfExecuting step S11 when the control cycle is over, turning off an auxiliary valve of an auxiliary phase change circuit connected with the ith bridge arm in the hybrid converter topology structure until the voltage of the hybrid converter topology structure is recovered to be stable, and executing step 11;
as shown in fig. 9 (b), step s11 is to turn on the thyristor valve of the i-th arm in the hybrid converter topology, turn off the auxiliary valve of the auxiliary commutation circuit connected to the i-th arm in the hybrid converter topology, and pass through
Figure BDA0002154175920000151
Thereafter, step S12 is executed;
s12, conducting a two-way valve connected with the ith bridge arm in the topological structure of the hybrid converter, and conducting an auxiliary valve of an auxiliary phase change circuit connected with the ith bridge arm in the topological structure of the hybrid converter
Figure BDA0002154175920000152
Switching on a resonant circuit of the ith bridge arm in the hybrid converter topology or a resonant circuit of an auxiliary phase change circuit connected with the ith bridge arm in the hybrid converter topology at any time, and executing the step S13 when a thyristor valve of the ith bridge arm in the hybrid converter topology is in a forward blocking state, a two-way valve connected with the ith bridge arm in the hybrid converter topology is forcibly switched off, and the resonant circuit of the ith bridge arm in the hybrid converter topology or the resonant circuit of the auxiliary phase change circuit connected with the ith bridge arm in the hybrid converter topology is switched off;
step S13, turning off an auxiliary valve of an auxiliary phase change circuit connected with the ith bridge arm in the topology structure of the hybrid converter, and enabling the auxiliary valve to pass through delta t'offThen, the process returns to step S11;
wherein, tf＜tq，Δt'offIn order to execute the time length of the thyristor valve of the ith bridge arm in the hybrid converter topology in the control period from the step S11 to the step S13, delta t1For conducting the delay time of the resonant circuit of the ith bridge arm in the topology structure of the hybrid converter or the resonant circuit of the auxiliary phase change circuit connected with the ith bridge arm in the topology structure of the hybrid converter, T is a control period, T0Is the control period start time.
Specifically, as shown in (a) of FIG. 11, tfAfter a failed commutation failure of the valve occurs at time V1, at tpTriggering the two-way valve DVa and the auxiliary valve Vp simultaneously at a time, then at tqTriggering the resonant circuit Cg1 at any moment, discharging the capacitor to the inductor, and forcibly offsetting the current of the main bridge arm valve to realize the current conversion from the main bridge arm to the auxiliary bridge arm; as shown in fig. 11 (b), after the main bridge arm current crosses zero, Cg1 is turned off, the V1 thyristor valve is turned off and subjected to a reverse voltage, and the V1 valve current is fully diverted to the auxiliary valve; as shown in fig. 11 (c), when the auxiliary valve Vp starts to close, the current is entirely transferred to the V3 valve.
Based on the same inventive concept, the present invention further provides a method for controlling the topology, as shown in fig. 9 (b), the method comprising:
s21, switching on a thyristor valve of the ith bridge arm in the topological structure of the hybrid converter, switching off an auxiliary valve of an auxiliary phase change circuit connected with the ith bridge arm in the topological structure of the hybrid converter, and enabling the auxiliary valve to pass through
Figure BDA0002154175920000161
Thereafter, step S22 is executed;
s22, conducting a two-way valve connected with the ith bridge arm in the topological structure of the hybrid converter, and conducting an auxiliary valve of an auxiliary phase change circuit connected with the ith bridge arm in the topological structure of the hybrid converter
Figure BDA0002154175920000162
Switching on a resonant circuit of the ith bridge arm in the hybrid converter topology or a resonant circuit of an auxiliary phase change circuit connected with the ith bridge arm in the hybrid converter topology at any time, and executing the step S23 when a thyristor valve of the ith bridge arm in the hybrid converter topology is in a forward blocking state, a two-way valve connected with the ith bridge arm in the hybrid converter topology is forcibly switched off, and the resonant circuit of the ith bridge arm in the hybrid converter topology or the resonant circuit of the auxiliary phase change circuit connected with the ith bridge arm in the hybrid converter topology is switched off;
s23, turning off an auxiliary valve of an auxiliary phase change circuit connected with the ith bridge arm in the topological structure of the hybrid converter, and enabling the auxiliary valve to pass through delta t'offThen, the process returns to step S21;
wherein, Δ t "offIn order to execute the time length of the thyristor valve of the ith bridge arm in the hybrid converter topology in the control period from the step S21 to the step S23, delta t1In order to conduct the delay time of the resonant circuit of the ith bridge arm in the topological structure of the hybrid converter or the resonant circuit of the auxiliary phase change circuit connected with the ith bridge arm in the topological structure of the hybrid converter, T is a control period, i belongs to [1,6]]。
Based on the same inventive concept, the invention also provides a control method of the topological structure, which comprises the following steps:
turning off an auxiliary valve of an auxiliary phase change circuit connected with the ith bridge arm in the topological structure of the hybrid converter, and turning off a two-way valve connected with the ith bridge arm in the topological structure of the hybrid converter, and executing the following steps;
step 21, conducting a thyristor valve of the ith bridge arm in the topological structure of the hybrid converter, and executing the step 22;
step 22, after a control period T, returning to the step 21;
wherein i ∈ [1,6 ].
When at t, as shown in FIG. 10 (a)fWhen detecting that the ith bridge arm in the topological structure of the hybrid converter has phase change failure or short-circuit fault at any moment, at tfA bidirectional valve connected with the ith bridge arm in the topological structure of the constantly conducted hybrid converter is at tfAn auxiliary valve of an auxiliary phase change circuit connected with the ith bridge arm in the topological structure of the time-conduction hybrid converter is at tqThe method comprises the steps of conducting a resonant circuit of the ith bridge arm in a hybrid converter topological structure or a resonant circuit of an auxiliary phase change circuit connected with the ith bridge arm in the hybrid converter topological structure at any time, when a thyristor valve of the ith bridge arm is in a forward blocking state, and the resonant circuit of the ith bridge arm in the hybrid converter topological structure or the resonant circuit of the auxiliary phase change circuit connected with the ith bridge arm in the hybrid converter topological structure is turned off, turning off a two-way valve connected with the ith bridge arm in the hybrid converter topological structure, turning off the auxiliary valve of the auxiliary phase change circuit connected with the ith bridge arm, and when t isfExecuting the step T11 when the control cycle is over until the voltage of the hybrid converter topological structure is recovered to be stable, turning off an auxiliary valve of an auxiliary phase change circuit connected with the ith bridge arm in the hybrid converter topological structure and turning off a two-way valve connected with the ith bridge arm in the hybrid converter topological structure, and executing the step 21;
as shown in fig. 10 (b), step t11 turns on the thyristor valve of the i-th arm in the hybrid converter topology, turns off the auxiliary valve of the auxiliary commutation circuit connected to the i-th arm in the hybrid converter topology, and turns off the hybrid converter topologyThe two-way valve connected with the ith bridge arm in the topological structure of the converter passes through
Figure BDA0002154175920000171
Thereafter, step T12 is executed;
and T12, conducting a two-way valve connected with the ith bridge arm in the topological structure of the hybrid converter, and conducting an auxiliary valve of an auxiliary phase change circuit connected with the ith bridge arm in the topological structure of the hybrid converter
Figure BDA0002154175920000172
Switching on a resonant circuit of the ith bridge arm in the hybrid converter topology or a resonant circuit of an auxiliary phase change circuit connected with the ith bridge arm in the hybrid converter topology at any time, and executing the step T13 when a thyristor valve of the ith bridge arm in the hybrid converter topology is in a forward blocking state and the resonant circuit of the ith bridge arm in the hybrid converter topology or the resonant circuit of the auxiliary phase change circuit connected with the ith bridge arm in the hybrid converter topology is switched off;
step T13, turning off a two-way valve connected with the ith arm in the topology structure of the hybrid converter, and turning off an auxiliary valve of an auxiliary phase change circuit connected with the ith arm in the topology structure of the hybrid converter, wherein the two-way valve passes through delta T'offThen, returning to the step T11;
wherein, tf＜tq，ΔT’offΔ T is a duration of the thyristor valve of the ith arm in the hybrid converter topology being in the forward blocking state in one control cycle from step T11 to step T131T is a control period for conducting the delay time of the resonant circuit of the ith bridge arm in the topological structure of the hybrid converter or the resonant circuit of the auxiliary phase change circuit connected with the ith bridge arm in the topological structure of the hybrid converter.
Based on the same inventive concept, the present invention further provides a method for controlling the topology, as shown in fig. 10 (b), the method comprising:
step T21, conducting and closing the thyristor valve of the ith bridge arm in the topological structure of the hybrid converterDisconnecting the auxiliary valve of the auxiliary phase change circuit connected with the ith bridge arm in the hybrid converter topology structure, and disconnecting the two-way valve connected with the ith bridge arm in the hybrid converter topology structure
Figure BDA0002154175920000181
Thereafter, step T22 is executed;
step T22, conducting a two-way valve connected with the ith bridge arm in the topological structure of the hybrid converter, conducting an auxiliary valve of an auxiliary phase change circuit connected with the ith bridge arm in the topological structure of the hybrid converter, and switching on the auxiliary valve
Figure BDA0002154175920000182
Switching on a resonant circuit of the ith bridge arm in the hybrid converter topology or a resonant circuit of an auxiliary phase change circuit connected with the ith bridge arm in the hybrid converter topology at any time, and executing the step T23 when a thyristor valve of the ith bridge arm in the hybrid converter topology is in a forward blocking state and the resonant circuit of the ith bridge arm in the hybrid converter topology or the resonant circuit of the auxiliary phase change circuit connected with the ith bridge arm in the hybrid converter topology is switched off;
and T23, turning off a two-way valve connected with the ith bridge arm in the topological structure of the hybrid converter, and turning off an auxiliary valve of an auxiliary phase change circuit connected with the ith bridge arm in the topological structure of the hybrid converter, wherein the two-way valve passes through delta T'offThen, returning to the step T21;
wherein, Delta T "offΔ T is a duration of the thyristor valve of the ith arm in the hybrid converter topology being in the forward blocking state in one control cycle from step T21 to step T231In order to conduct the delay time of the resonant circuit of the ith bridge arm in the topological structure of the hybrid converter or the resonant circuit of the auxiliary phase change circuit connected with the ith bridge arm in the topological structure of the hybrid converter, T is a control period, i belongs to [1,6]]。
To sum up, the present invention relates to a topology structure of a hybrid converter and a control method thereof, including: the three-phase six-bridge arm circuit comprises a three-phase six-bridge arm circuit and an auxiliary commutation circuit which is connected with the direct current side of the three-phase six-bridge arm circuit in parallel and has the capabilities of controllable turn-off of forward current and blocking of forward and reverse voltage; the auxiliary phase-changing circuit is respectively connected with the connection points of the upper bridge arm and the lower bridge arm of each phase of bridge arm circuit in the three-phase six-bridge arm circuit through the two-way valves on the alternating current buses in the three-phase alternating current buses; the added auxiliary commutation circuit can transfer commutation current and flexibly control commutation time when commutation of the converter fails, and rapidly recover commutation between two bridge arms by using the high-current turn-off characteristic of a turn-off device, thereby greatly accelerating the recovery time of the converter after commutation failure; the shut-off valve introduced by the main bridge arm is shut off when in failure, so that the current of the main bridge arm is zero, reverse voltage is provided, the phase change time area of the thyristor valve is increased, the thyristor valve is reliably shut off, voltage stress is mainly borne by the thyristor valve, and the series stages are fewer, so that the loss of devices is lower; according to the bidirectional valve, a transfer path of current of the main bridge arm to the auxiliary phase change circuit is provided during failure, and the upper bridge arm and the lower bridge arm of each phase are respectively changed to the auxiliary phase change circuit by controlling the opening direction of the bidirectional valve; when the hybrid converter topological structure adopts the alternate operation control method, the occurrence of short-circuit current and commutation failure can be avoided, and the overall reliability of the converter is improved.
As will be appreciated by one skilled in the art, embodiments of the present application may be provided as a method, system, or computer program product. Accordingly, the present application may take the form of an entirely hardware embodiment, an entirely software embodiment or an embodiment combining software and hardware aspects. Furthermore, the present application may take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, and the like) having computer-usable program code embodied therein.
The present application is described with reference to flowchart illustrations and/or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the application. It will be understood that each flow and/or block of the flow diagrams and/or block diagrams, and combinations of flows and/or blocks in the flow diagrams and/or block diagrams, can be implemented by computer program instructions. These computer program instructions may be provided to a processor of a general purpose computer, special purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create means for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.
These computer program instructions may also be stored in a computer-readable memory that can direct a computer or other programmable data processing apparatus to function in a particular manner, such that the instructions stored in the computer-readable memory produce an article of manufacture including instruction means which implement the function specified in the flowchart flow or flows and/or block diagram block or blocks.
These computer program instructions may also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer implemented process such that the instructions which execute on the computer or other programmable apparatus provide steps for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.
Finally, it should be noted that: the above embodiments are only for illustrating the technical solutions of the present invention and not for limiting the same, and although the present invention is described in detail with reference to the above embodiments, those of ordinary skill in the art should understand that: modifications and equivalents may be made to the embodiments of the invention without departing from the spirit and scope of the invention, which is to be covered by the claims.

Claims (26)

1. A forced-commutated hybrid converter topology, the topology comprising: the three-phase six-bridge arm circuit comprises a three-phase six-bridge arm circuit and an auxiliary commutation circuit which is connected with the direct current side of the three-phase six-bridge arm circuit in parallel and has the capabilities of controllable turn-off of forward current and blocking of forward and reverse voltage;
the auxiliary phase-changing circuit is respectively connected with the connection points of the upper bridge arm and the lower bridge arm of each phase of bridge arm circuit in the three-phase six-bridge arm circuit through two-way valves with two-way opening and two-way pressure resistance on each phase of alternating current bus in the three-phase alternating current bus.
2. The topology of claim 1, wherein an upper bridge arm and a lower bridge arm of each phase of the three-phase six-bridge arm circuit are composed of a thyristor valve and a resonant commutation loop with capacitance one-way controllable discharge which are connected in series.
3. The topology of claim 1, wherein an upper leg and a lower leg of each phase leg circuit of the three-phase six-leg circuit are comprised of thyristor valves.
4. The topology of claim 2, wherein the auxiliary commutation circuit consists of an upper leg auxiliary valve and a lower leg auxiliary valve in series;
and the connection point between the upper bridge arm auxiliary valve and the lower bridge arm auxiliary valve is respectively connected with the connection point of the upper bridge arm and the lower bridge arm of each phase of bridge arm circuit in the three-phase six-bridge arm circuit through the two-way valve on each phase of alternating current bus in the three-phase alternating current bus.
5. The topology of claim 2, wherein said auxiliary commutation circuit is a three-phase six leg configuration;
each phase of bridge arm structure in the three-phase six-bridge arm structure consists of an upper bridge arm auxiliary valve and a lower bridge arm auxiliary valve which are connected in series;
and the connection points between the upper bridge arm auxiliary valve and the lower bridge arm auxiliary valve of each phase of bridge arm structure in the three-phase six-bridge arm structure are respectively connected with the connection points of the upper bridge arm and the lower bridge arm of each phase of bridge arm circuit in the three-phase six-bridge arm circuit through the two-way valve on each alternating current bus in the three-phase alternating current bus.
6. The topology of claim 3, wherein the auxiliary commutation circuit consists of an upper leg auxiliary valve, an upper leg resonant tank, a lower leg auxiliary valve, and a lower leg resonant tank in series;
and the connection point between the upper bridge arm resonant circuit and the lower bridge arm auxiliary valve is respectively connected with the connection point of the upper bridge arm and the lower bridge arm of each phase of bridge arm circuit in the three-phase six-bridge arm circuit through the two-way valve on each phase of alternating current bus in the three-phase alternating current bus.
7. The topology of claim 3, wherein said auxiliary commutation circuit is a three-phase six leg configuration;
each phase of bridge arm structure in the three-phase six-bridge arm structure consists of an upper bridge arm auxiliary valve, an upper bridge arm resonant circuit, a lower bridge arm auxiliary valve and a lower bridge arm resonant circuit which are connected in series;
and the connection point between the upper bridge arm resonant circuit and the lower bridge arm auxiliary valve of each phase of bridge arm structure in the three-phase six-bridge arm structure is respectively connected with the connection point between the upper bridge arm and the lower bridge arm of each phase of bridge arm circuit in the three-phase six-bridge arm circuit through the two-way valve on each alternating current bus in the three-phase alternating current bus.
8. The topology of claim 2 or 3, wherein the thyristor valve is comprised of a plurality of thyristors and a buffer component in series or parallel with each thyristor of the plurality of thyristors.
9. The topology of claim 2, 6 or 7, wherein said resonant tank comprises: the device comprises an inductor and a discharge branch circuit connected with the inductor in parallel.
10. The topology of claim 9, wherein said discharge branch is comprised of a pre-charge capacitor and a discharge timing control circuit in series;
the discharge time sequence control circuit is composed of a plurality of controllable power electronic devices connected in series in the forward direction and a buffer component connected with the plurality of controllable electronic devices connected in series or in parallel.
11. The topology of claim 9, wherein said discharge branch is comprised of a pre-charge capacitor and a control branch in series;
the control branch circuit consists of a first discharge time sequence control circuit and a second discharge time sequence control circuit which is reversely connected with the first discharge time sequence control circuit in parallel;
the first discharge time sequence control circuit and the second discharge time sequence control circuit are respectively composed of a plurality of controllable power electronic devices which are connected in series in the forward direction and a buffer component which is connected with the plurality of controllable electronic devices which are connected in series in the forward direction or in parallel.
12. The topology of claim 9, wherein the discharge branch consists of a first control branch, a pre-charge capacitor, and a second control branch in parallel;
the first control branch circuit and the second control branch circuit are respectively composed of two groups of discharge time sequence control circuits which are connected in series in the forward direction;
the connection points of the two groups of discharge time sequence control circuits of the first control branch circuit and the second control branch circuit are connected with the two ends of the inductor;
the discharge time sequence control circuit is composed of a plurality of controllable power electronic devices which are connected in series in the forward direction and a buffer component which is connected with the plurality of controllable electronic devices which are connected in series in the forward direction or in parallel.
13. The topological structure according to any one of claims 4 to 7, wherein the upper bridge arm auxiliary valve and the lower bridge arm auxiliary valve are each composed of a plurality of auxiliary sub-modules connected in series and a buffer component connected in series or in parallel with each of the plurality of auxiliary sub-modules connected in series;
the auxiliary sub-module is composed of one or more of fully-controlled power electronic devices with reverse voltage blocking capability, or is composed of fully-controlled power electronic devices without reverse voltage blocking capability, diodes in reverse parallel connection with the fully-controlled power electronic devices without reverse voltage blocking capability, and buffer components in series connection or parallel connection with the fully-controlled power electronic devices without reverse voltage blocking capability.
14. The topological structure according to any one of claims 4 to 7, wherein said upper bridge arm auxiliary valve and lower bridge arm auxiliary valve are each composed of a first auxiliary branch, a buffer component and a second auxiliary branch connected in parallel;
the first auxiliary branch and the second auxiliary branch are composed of two groups of auxiliary sequential control branches which are connected in series in the forward direction;
the auxiliary time sequence control circuit consists of a plurality of auxiliary sub-modules which are connected in series and buffer components which are respectively connected with each auxiliary sub-module in the plurality of auxiliary sub-modules in series or in parallel;
the auxiliary sub-module is composed of one or more of fully-controlled power electronic devices with reverse voltage blocking capability, or is composed of fully-controlled power electronic devices without reverse voltage blocking capability, diodes in reverse parallel connection with the fully-controlled power electronic devices without reverse voltage blocking capability and buffer components in series connection or parallel connection with the fully-controlled power electronic devices without reverse voltage blocking capability;
the external connection point of the first auxiliary branch and the external connection point of the second auxiliary branch are respectively connection points of two groups of auxiliary time sequence control branches of the first auxiliary branch and the second auxiliary branch.
15. The topology structure according to any one of claims 4 to 7, wherein the upper bridge arm auxiliary valve and the lower bridge arm auxiliary valve are respectively a first diode branch, an auxiliary branch and a second diode branch which are connected in parallel;
the first diode branch circuit and the second diode branch circuit are respectively composed of two groups of diode time sequence control branch circuits which are connected in series in the forward direction;
the auxiliary branch circuit consists of a plurality of auxiliary sub-modules which are connected in series and buffer components which are respectively connected with each auxiliary sub-module in the plurality of auxiliary sub-modules which are connected in series or in parallel;
the auxiliary sub-module is composed of one or more of fully-controlled power electronic devices with reverse voltage blocking capability, or is composed of fully-controlled power electronic devices without reverse voltage blocking capability, diodes in reverse parallel connection with the fully-controlled power electronic devices without reverse voltage blocking capability and buffer components in series connection or parallel connection with the fully-controlled power electronic devices without reverse voltage blocking capability;
the external connection point of the first diode branch and the external connection point of the second diode branch are respectively connection points of two groups of diode time sequence control branches of the first diode branch and the second diode branch.
16. The topological structure according to any one of claims 4 to 7, wherein each of said upper bridge arm auxiliary valve and said lower bridge arm auxiliary valve comprises a third auxiliary branch and a fourth auxiliary branch in anti-parallel connection with said third auxiliary branch;
the third auxiliary branch is composed of a plurality of auxiliary sub-modules connected in series and buffer components connected in series or in parallel with each auxiliary sub-module in the plurality of auxiliary sub-modules connected in series respectively;
the fourth auxiliary branch consists of a capacitor connected in series, a plurality of auxiliary sub-modules connected in series and a buffer component connected in series or in parallel with each of the plurality of auxiliary sub-modules connected in series;
the auxiliary sub-module is composed of one or more of fully-controlled power electronic devices with reverse voltage blocking capability, or is composed of fully-controlled power electronic devices without reverse voltage blocking capability, diodes in reverse parallel connection with the fully-controlled power electronic devices without reverse voltage blocking capability, and buffer components in series connection or parallel connection with the fully-controlled power electronic devices without reverse voltage blocking capability.
17. The topology of claim 1, wherein the bidirectional valve is comprised of a first thyristor leg and a second thyristor leg connected in anti-parallel therewith;
the first thyristor branch circuit and the second thyristor branch circuit are both composed of a plurality of thyristor modules connected in series;
the thyristor module consists of a thyristor and a buffer component connected with the thyristor in series or in parallel.
18. The topology of claim 1, wherein the bi-directional valve consists of a first bi-directional valve branch and a second bi-directional valve branch connected in anti-parallel with the first bi-directional valve branch;
the first bidirectional valve branch and the second bidirectional valve branch are both composed of a first bidirectional valve timing control branch and a second bidirectional valve timing control branch which is reversely connected with the first bidirectional valve timing control branch in series;
the first two-way valve timing sequence control branch circuit and the second two-way valve timing sequence control branch circuit are respectively composed of a plurality of auxiliary sub-modules which are connected in series and buffer parts which are respectively connected with each auxiliary sub-module in the plurality of auxiliary sub-modules which are connected in series or in parallel;
the auxiliary sub-module is composed of one or more of fully-controlled power electronic devices with reverse voltage blocking capability, or is composed of fully-controlled power electronic devices without reverse voltage blocking capability, diodes in reverse parallel connection with the fully-controlled power electronic devices without reverse voltage blocking capability, and buffer components in series connection or parallel connection with the fully-controlled power electronic devices without reverse voltage blocking capability.
19. The topology of claim 1, wherein the bi-directional valve consists of a third bi-directional valve branch, an auxiliary branch, and a fourth bi-directional valve branch connected in parallel;
the third two-way valve branch and the fourth two-way valve branch are both composed of two-way valve timing control branches which are connected in series in the forward direction;
the two-way valve time sequence control circuits are composed of a plurality of diodes which are connected in series in the forward direction and a plurality of buffer components which are connected in series or in parallel respectively;
the auxiliary branch circuit consists of a plurality of auxiliary sub-modules which are connected in series and buffer components which are respectively connected with each auxiliary sub-module in the plurality of auxiliary sub-modules which are connected in series or in parallel;
the auxiliary sub-module is composed of one or more of fully-controlled power electronic devices with reverse voltage blocking capability, or is composed of fully-controlled power electronic devices without reverse voltage blocking capability, diodes in reverse parallel connection with the fully-controlled power electronic devices without reverse voltage blocking capability and buffer components in series connection or parallel connection with the fully-controlled power electronic devices without reverse voltage blocking capability;
the external connection point of the third two-way valve branch and the external connection point of the fourth two-way valve branch are respectively the connection point of the two diode time sequence control branches of the third two-way valve branch and the connection point of the two diode time sequence control branches of the fourth two-way valve branch.
20. The topology of any of claims 10 to 12 and 17 to 19, wherein the buffer component is composed of one or more of a capacitor, a resistor-capacitor circuit, a diode, an inductor or a lightning arrester connected in series or in parallel.
21. A method for controlling a topology according to any of claims 1 to 20, said method comprising:
turning off an auxiliary valve of an auxiliary phase change circuit connected with the ith bridge arm in the topological structure of the hybrid converter, and executing the following steps;
step 11, conducting a thyristor valve of the ith bridge arm in the topological structure of the hybrid converter, and executing step 12;
step 12, after a control period T, returning to the step 11;
wherein i ∈ [1,6 ].
22. The method of claim 21, when at tfWhen detecting that the ith bridge arm in the topological structure of the hybrid converter has phase change failure or short-circuit fault at any moment, at tfA bidirectional valve connected with the ith bridge arm in the topological structure of the constantly conducted hybrid converter is at tfTime-of-day on-mixAn auxiliary valve of an auxiliary phase change circuit connected with the ith bridge arm in the combined converter topological structure is arranged at tqThe method comprises the steps of conducting a resonant circuit of the ith bridge arm in a hybrid converter topological structure or a resonant circuit of an auxiliary phase change circuit connected with the ith bridge arm in the hybrid converter topological structure at any time, when a thyristor valve of the ith bridge arm in the hybrid converter topological structure is in a forward blocking state, a two-way valve connected with the ith bridge arm in the hybrid converter topological structure is forced to be turned off, and the resonant circuit of the ith bridge arm in the hybrid converter topological structure or the resonant circuit of the auxiliary phase change circuit connected with the ith bridge arm in the hybrid converter topological structure is turned off, turning off the auxiliary valve of the auxiliary phase change circuit connected with the ith bridge arm, and when t isfExecuting step S11 when the control cycle is over, turning off an auxiliary valve of an auxiliary phase change circuit connected with the ith bridge arm in the hybrid converter topology structure until the voltage of the hybrid converter topology structure is recovered to be stable, and executing step 11; s11, switching on a thyristor valve of the ith bridge arm in the topological structure of the hybrid converter, switching off an auxiliary valve of an auxiliary phase change circuit connected with the ith bridge arm in the topological structure of the hybrid converter, and enabling the auxiliary valve to pass through
Figure FDA0002154175910000051
Thereafter, step S12 is executed;
s12, conducting a two-way valve connected with the ith bridge arm in the topological structure of the hybrid converter, and conducting an auxiliary valve of an auxiliary phase change circuit connected with the ith bridge arm in the topological structure of the hybrid converter
Figure FDA0002154175910000052
The resonant circuit of the ith bridge arm in the hybrid converter topology or the resonant circuit of the auxiliary phase change circuit connected with the ith bridge arm in the hybrid converter topology is switched on at any time, when the thyristor valve of the ith bridge arm in the hybrid converter topology is in a forward blocking state, the two-way valve connected with the ith bridge arm in the hybrid converter topology is forced to be switched off, and the harmonic circuit of the ith bridge arm in the hybrid converter topology is switched offWhen the resonant circuit of the auxiliary phase change circuit connected with the ith bridge arm in the topological structure of the vibration circuit or the hybrid converter is turned off, executing the step S13;
step S13, turning off an auxiliary valve of an auxiliary phase change circuit connected with the ith bridge arm in the topology structure of the hybrid converter, and enabling the auxiliary valve to pass through delta t'offThen, the process returns to step S11;
wherein, tf＜tq，Δt'offIn order to execute the time length of the thyristor valve of the ith bridge arm in the hybrid converter topology in the control period from the step S11 to the step S13, delta t1T is a control period for conducting the delay time of the resonant circuit of the ith bridge arm in the topological structure of the hybrid converter or the resonant circuit of the auxiliary phase change circuit connected with the ith bridge arm in the topological structure of the hybrid converter.
23. A method for controlling a topology according to any of claims 1 to 20, said method comprising:
s21, switching on a thyristor valve of the ith bridge arm in the topological structure of the hybrid converter, switching off an auxiliary valve of an auxiliary phase change circuit connected with the ith bridge arm in the topological structure of the hybrid converter, and enabling the auxiliary valve to pass through
Figure FDA0002154175910000061
Thereafter, step S22 is executed;
s22, conducting a two-way valve connected with the ith bridge arm in the topological structure of the hybrid converter, and conducting an auxiliary valve of an auxiliary phase change circuit connected with the ith bridge arm in the topological structure of the hybrid converter
Figure FDA0002154175910000062
The resonant circuit of the ith bridge arm in the hybrid converter topology structure or the resonant circuit of the auxiliary phase change circuit connected with the ith bridge arm in the hybrid converter topology structure is switched on at any time, and when the thyristor valve of the ith bridge arm in the hybrid converter topology structure is in a forward blocking state and the thyristor valve of the ith bridge arm in the hybrid converter topology structure is in a forward blocking state, the thyristor valve of the ith bridge arm in the hybrid converter topology structure is in a forward blocking stateWhen the bidirectional valve connected with the arm is forced to be turned off and the resonant circuit of the ith bridge arm in the hybrid converter topology or the resonant circuit of the auxiliary phase change circuit connected with the ith bridge arm in the hybrid converter topology is turned off, executing the step S23;
s23, turning off an auxiliary valve of an auxiliary phase change circuit connected with the ith bridge arm in the topological structure of the hybrid converter, and enabling the auxiliary valve to pass through delta t'offThen, the process returns to step S21;
wherein, Δ t "offIn order to execute the time length of the thyristor valve of the ith bridge arm in the hybrid converter topology in the control period from the step S21 to the step S23, delta t1In order to conduct the delay time of the resonant circuit of the ith bridge arm in the topological structure of the hybrid converter or the resonant circuit of the auxiliary phase change circuit connected with the ith bridge arm in the topological structure of the hybrid converter, T is a control period, i belongs to [1,6]]。
24. A method for controlling a topology according to any of claims 1 to 20, said method comprising:
turning off an auxiliary valve of an auxiliary phase change circuit connected with the ith bridge arm in the topological structure of the hybrid converter, and turning off a two-way valve connected with the ith bridge arm in the topological structure of the hybrid converter, and executing the following steps;
step 21, conducting a thyristor valve of the ith bridge arm in the topological structure of the hybrid converter, and executing the step 22;
step 22, after a control period T, returning to the step 21;
wherein i ∈ [1,6 ].
25. The method of claim 24, when at tfWhen detecting that the ith bridge arm in the topological structure of the hybrid converter has phase change failure or short-circuit fault at any moment, at tfA bidirectional valve connected with the ith bridge arm in the topological structure of the constantly conducted hybrid converter is at tfAuxiliary valve of auxiliary phase change circuit connected with ith bridge arm in moment-conducting hybrid converter topological structureAt tqThe method comprises the steps of conducting a resonant circuit of the ith bridge arm in a hybrid converter topological structure or a resonant circuit of an auxiliary phase change circuit connected with the ith bridge arm in the hybrid converter topological structure at any time, when a thyristor valve of the ith bridge arm is in a forward blocking state, and the resonant circuit of the ith bridge arm in the hybrid converter topological structure or the resonant circuit of the auxiliary phase change circuit connected with the ith bridge arm in the hybrid converter topological structure is turned off, turning off a two-way valve connected with the ith bridge arm in the hybrid converter topological structure, turning off the auxiliary valve of the auxiliary phase change circuit connected with the ith bridge arm, and when t isfExecuting the step T11 when the control cycle is over until the voltage of the hybrid converter topological structure is recovered to be stable, turning off an auxiliary valve of an auxiliary phase change circuit connected with the ith bridge arm in the hybrid converter topological structure and turning off a two-way valve connected with the ith bridge arm in the hybrid converter topological structure, and executing the step 21;
and step T11, switching on a thyristor valve of the ith bridge arm in the topological structure of the hybrid converter, switching off an auxiliary valve of an auxiliary phase change circuit connected with the ith bridge arm in the topological structure of the hybrid converter, and switching off a two-way valve connected with the ith bridge arm in the topological structure of the hybrid converter, wherein the two-way valve passes through
Figure FDA0002154175910000071
Thereafter, step T12 is executed;
and T12, conducting a two-way valve connected with the ith bridge arm in the topological structure of the hybrid converter, and conducting an auxiliary valve of an auxiliary phase change circuit connected with the ith bridge arm in the topological structure of the hybrid converter
Figure FDA0002154175910000072
The resonant circuit of the ith bridge arm in the hybrid converter topology structure or the resonant circuit of the auxiliary phase change circuit connected with the ith bridge arm in the hybrid converter topology structure is switched on at any time, when the thyristor valve of the ith bridge arm in the hybrid converter topology structure is in a forward blocking state and the resonant circuit of the ith bridge arm in the hybrid converter topology structure or the resonant circuit of the hybrid converter topology structure is in a hybrid converter stateWhen the resonant circuit of the auxiliary commutation circuit connected with the ith bridge arm in the topological structure is turned off, executing a step T13;
step T13, turning off a two-way valve connected with the ith arm in the topology structure of the hybrid converter, and turning off an auxiliary valve of an auxiliary phase change circuit connected with the ith arm in the topology structure of the hybrid converter, wherein the two-way valve passes through delta T'offThen, returning to the step T11;
wherein, tf＜tq，ΔT’offΔ T is a duration of the thyristor valve of the ith arm in the hybrid converter topology being in the forward blocking state in one control cycle from step T11 to step T131T is a control period for conducting the delay time of the resonant circuit of the ith bridge arm in the topological structure of the hybrid converter or the resonant circuit of the auxiliary phase change circuit connected with the ith bridge arm in the topological structure of the hybrid converter.
26. A method for controlling a topology according to any of claims 1 to 20, said method comprising:
and T21, switching on a thyristor valve of the ith bridge arm in the topological structure of the hybrid converter, switching off an auxiliary valve of an auxiliary phase change circuit connected with the ith bridge arm in the topological structure of the hybrid converter, and switching off a two-way valve connected with the ith bridge arm in the topological structure of the hybrid converter, wherein the two-way valve passes through
Figure FDA0002154175910000081
Thereafter, step T22 is executed;
step T22, conducting a two-way valve connected with the ith bridge arm in the topological structure of the hybrid converter, conducting an auxiliary valve of an auxiliary phase change circuit connected with the ith bridge arm in the topological structure of the hybrid converter, and switching on the auxiliary valve
Figure FDA0002154175910000082
The resonant circuit of the ith bridge arm in the hybrid converter topology structure or the resonant circuit of the auxiliary phase change circuit connected with the ith bridge arm in the hybrid converter topology structure is switched on at any time when the hybrid converter topology structure is mixedWhen the thyristor valve of the ith bridge arm in the topological structure of the formula converter is in a forward blocking state and the resonant circuit of the ith bridge arm in the topological structure of the hybrid converter or the resonant circuit of the auxiliary phase-change circuit connected with the ith bridge arm in the topological structure of the hybrid converter is turned off, executing a step T23;
and T23, turning off a two-way valve connected with the ith bridge arm in the topological structure of the hybrid converter, and turning off an auxiliary valve of an auxiliary phase change circuit connected with the ith bridge arm in the topological structure of the hybrid converter, wherein the two-way valve passes through delta T'offThen, returning to the step T21;
wherein, Delta T "offΔ T is a duration of the thyristor valve of the ith arm in the hybrid converter topology being in the forward blocking state in one control cycle from step T21 to step T231In order to conduct the delay time of the resonant circuit of the ith bridge arm in the topological structure of the hybrid converter or the resonant circuit of the auxiliary phase change circuit connected with the ith bridge arm in the topological structure of the hybrid converter, T is a control period, i belongs to [1,6]]。
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