CN102244468B - High-reliability medium voltage frequency converter adopting redundancy design - Google Patents
High-reliability medium voltage frequency converter adopting redundancy design Download PDFInfo
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- CN102244468B CN102244468B CN201010180602.1A CN201010180602A CN102244468B CN 102244468 B CN102244468 B CN 102244468B CN 201010180602 A CN201010180602 A CN 201010180602A CN 102244468 B CN102244468 B CN 102244468B
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Abstract
The invention discloses a frequency converter, which comprises power units, isolating transformers, bypassing contactors and high voltage switches, wherein the number of the power units is N; the number of the bypassing contactors is X; the number of the high voltage switches is X; N, X and N/X are all positive integers, and X is more than 1; the bypassing contactors are used for bypassing N/X power units; the two ends of each of the N/X power units are connected with the bypassing contactor respectively; when the power units of each group or a corresponding isolating transformer works normally, the bypassing contactors are in an off state; and when the power units of a certain group or the corresponding isolating transformer fails, the bypassing contactors are switched on, and simultaneously the high voltage switch between the corresponding isolating transformer and a high voltage bus is switched off to switch a main loop on. By the frequency converter and a method provided by the invention, the acceptable failure rate of the whole system is greatly increased; moreover, the full-load running of the system can be realized without derating in a failure.
Description
Technical field
The present invention relates to industrial electric transmission field, relate in particular to a kind of frequency converter and frequency converter control method.
Background technology
In current industrial electric transmission field, the structure of high voltage converter mostly be take units in series mode as main, because such topological structure can greatly improve output waveform, realizes perfectly without harmonic wave.
As shown in Figure 1, the system of six power cells of every phase (A1-A6, B1-B6, C1-C6) of take series connection is example, described power cell is connected with the bus of three-phase high-voltage power supply (6kV three-phase alternating-current supply as shown in FIG.), therefore often can obtain mutually 13 different electric pressures, and, utilize pulse-width modulation to realize the folded ripple output of power cell.Between three-phase converter module, adopt " Y " type connection, the neutral ground that " Y " type connects, thus obtain the three-phase high-voltage power supply of variable frequency.
Figure 2 shows that the circuit topological structure of the high voltage converter of Fig. 1, all unit are by 202 power supplies of an isolating transformer.The secondary winding of this isolating transformer 202 has 18 groups of taps, and every group of tap output three-phase alternating voltage is 18 power cell A1-A6, B1-B6, C1-C6 power supply.After power unit cascade, the folded wave voltage that output frequency is variable, realizes the speed governing to motor 203.
But; there is a problem in the frequency converter of this structure: when certain power cell breaks down, or isolating transformer 202 breaks down, and frequency converter can be whole out of service immediately so; cause motor 203 to lose power supply and shut down, this impacts whole system can be very large.For example, in the cage application dragging at motor, if there is unexpected shutdown, can make the staff in cage not feel well.
There is at present the technical scheme of a kind of " unit bypass " to solve this problem.As shown in Figure 3, in the time of can not working on when certain power cell generation fuse fault, overheated or IGBT fault, the power cell on this power cell and in addition two-phase relevant position is by auto by pass for the schematic diagram of " unit bypass ".For example: when A3 cell failure, A3, B3, the bypass together of C3 unit, now Q1～Q4 blocks output, controllable silicon k conducting, branch road L1 and branch road L2, by the conducting of DP1～DP4 diode bridge, to guarantee frequency converter continuous operation, and send bypass alarm.
" but unit bypass " can not meet the reliability requirement of elevator system, and problem is:
1, first, power unit by-pass itself is exactly a kind of defective operational mode.Because frequency converter is in, fall appearance running status, can cause the close reduction of magnetic, thereby cause that the motor feels hot, increase, so such scheme can not, as long-term operational mode, finally also need to shut down rear solution fault.In practical application, do not have an equipment with bypass mode, to move for a long time;
2, in some cases, power cell is bypass successfully.For example: the power supply of the circuit board of power cell is got A, C two-phase alternating current by transformer, if but the fuse of A, C two-phase break down, the circuit board of power cell cannot obtain power supply, now uncontrollable controllable silicon carries out bypass.Similarly, such as: if IGBT of power cell inside, electric capacity etc. have the device of electric conducting material, break down, now the circuit board of power cell also may be destroyed, thereby cannot guarantee completing of bypass.
In addition, itself also has shortcoming " unit bypass ": inversion link in unit (is the inverter bridge DI1-DI6 in Fig. 3, Q1～Q4) be long-term and bypass link (being the thyristor part in Fig. 3) while parallel running, therefore very likely because of the damage of silicon-controlled device, cause the fault of inverter bridge, thereby make whole power cell " paralysis ", this is to take power frequency as basic engineering because of controllable silicon, so controllable silicon can not bear the erosion of long-term high frequency voltage.
So, be necessary to design a kind of novel high-reliability high frequency converter, to the operation risk of whole system is reduced greatly.
Summary of the invention
For the defect of prior art, the object of the present invention is to provide a kind of downtime of shorter frequency-converter device, to the system that frequency converter drives is moved more reliably.
Frequency converter provided by the invention comprises power cell, isolating transformer, bypass contactor and high-voltage switch gear, wherein: the number of power cell is N; The number of bypass contactor is X; The number of high-voltage switch gear is X, and N, X, N/X are positive integer, and X > 1.Described power cell connects with " Y " type connection, and the input of power cell is connected with the secondary side of isolating transformer, the neutral ground that " Y " type connects, the three-phase that " Y " type connects is connected with three-phase high-voltage bus respectively, and the power cell being connected with every phase high voltage bus forms by N/3 power unit cascade.Described isolating transformer is used for connecting high voltage bus and power cell, a described N power cell is divided into X group, every group comprises N/X power cell, a described N/X power cell comprises the power cell being evenly distributed in three-phase, every individual power cell of N/ (3 * X) that comprises mutually, the power cell of the N/X in every group is connected with the input of power cell by an isolating transformer.Described high-voltage switch gear is used for connecting isolating transformer and high voltage bus, and each isolating transformer is connected with high voltage bus by a high-voltage switch gear.Described bypass contactor is for N/X the power cell of every group carried out to bypass, a bypass contactor of described N/X power cell two ends parallel connection, and when the power cell of every group or corresponding isolating transformer are normally worked, bypass contactor is in off-state; When wherein the power cell of a group or corresponding isolating transformer break down, bypass contactor is closed, and the high-voltage switch gear between corresponding isolating transformer and high voltage bus disconnects simultaneously.
Preferably, N is that 18, X is 2, and described frequency converter comprises 18 power cells, the first isolating transformer, the second isolating transformer.Wherein, described power cell connects with " Y " type connection, and the input of power cell is connected with the secondary side of isolating transformer, the neutral ground that " Y " type connects, the three-phase that " Y " type connects is connected with three-phase high-voltage bus respectively, is six power unit cascades forms with the power cell being often connected; Described isolating transformer is used for connecting high voltage bus and power cell, described 18 power cells are divided into two groups, every group comprises nine power cells, described nine power cells comprise the power cell being evenly distributed in three-phase, often comprise mutually three power cells, nine power cells in every group are connected with the input of power cell by an isolating transformer.
Preferably, N is that 27, X is 3, and described frequency converter comprises 27 power cells, the first isolating transformer, the second isolating transformer, the 3rd isolating transformer.Wherein, described power cell connects with " Y " type connection, and the input of power cell is connected with the secondary side of isolating transformer, the neutral ground that " Y " type connects, the three-phase that " Y " type connects is connected with three-phase high-voltage bus respectively, is nine power unit cascades forms with the power cell being often connected; Described isolating transformer is used for connecting high voltage bus and power cell, described 27 power cells are divided into three groups, every group comprises nine power cells, described nine power cells comprise the power cell being evenly distributed in three-phase, often comprise mutually three power cells, nine power cells in every group are connected with the input of power cell by an isolating transformer.
Preferably, described frequency converter is vector-control frequency converter, and described vector-control frequency converter also comprises the reactor being connected between each power cell and corresponding isolating transformer, load and the filter element of described reactor during as energy feedback.
The present invention also provides a kind of frequency converter control method, and described frequency converter comprises power cell, isolating transformer, bypass contactor and high-voltage switch gear, wherein: the number of power cell is N; The number of bypass contactor is X; The number of high-voltage switch gear is X, N, X, N/X are positive integer, and X > 1, described power cell connects with " Y " type connection, and the input of power cell is connected with the secondary side of isolating transformer, the neutral ground that " Y " type connects, the three-phase that " Y " type connects is connected with three-phase high-voltage bus respectively, is N/3 power unit cascade forms with the power cell being often connected; Described isolating transformer is used for connecting high voltage bus and power cell, a described N power cell is divided into X group, every group comprises N/X power cell, a described N/X power cell comprises the power cell being evenly distributed in three-phase, every individual power cell of N/ (3 * X) that comprises mutually, the power cell of the N/X in every group is connected with the input of power cell by an isolating transformer; Described high-voltage switch gear is used for connecting isolating transformer and high voltage bus, and each isolating transformer is connected with high voltage bus by a high-voltage switch gear; Described bypass contactor carries out bypass for N/X the power cell to every group, a described N/X power cell two ends bypass contactor in parallel,
Said method comprising the steps of: a. detects the operating state of respectively connect power cell and corresponding isolating transformer; B. when wherein the operating state of the power cell of a group or isolating transformer is malfunction, the bypass contactor of closed and the power cell parallel connection of connecting of breaking down, simultaneously by the high-voltage switch gear disconnection between corresponding isolating transformer and high voltage bus.
Preferably, described frequency converter comprises 18 power cells, the first isolating transformer, the second isolating transformer, wherein, described power cell connects with " Y " type connection, and the input of power cell is connected with the secondary side of isolating transformer, the neutral ground that " Y " type connects, the three-phase that " Y " type connects is connected with three-phase high-voltage bus respectively, is six power unit cascades forms with the power cell being often connected; Described isolating transformer is used for connecting high voltage bus and power cell, described 18 power cells are divided into two groups, every group comprises nine power cells, described nine power cells comprise the power cell being evenly distributed in three-phase, often comprise mutually three power cells, nine power cells in every group are connected with the input of power cell by an isolating transformer.。
Preferably, described frequency converter comprises 27 power cells, the first isolating transformer, the second isolating transformer, the 3rd isolating transformer, wherein, described power cell connects with " Y " type connection, and the input of power cell is connected with the secondary side of isolating transformer, the neutral ground that " Y " type connects, the three-phase that " Y " type connects is connected with three-phase high-voltage bus respectively, is nine power unit cascades forms with the power cell being often connected; Described isolating transformer is used for connecting high voltage bus and power cell, described 27 power cells are divided into three groups, every group comprises nine power cells, described nine power cells comprise the power cell being evenly distributed in three-phase, often comprise mutually three power cells, nine power cells in every group are connected with the input of power cell by an isolating transformer.
Preferably, in step a, by galvanometer, potentiometer, detect electric current, the voltage of detection power unit and corresponding isolating transformer, to detect the operating state of respectively connect power cell and corresponding isolating transformer.
Preferably, step b also comprises: when the power cell of every group or corresponding isolating transformer are normally worked, keep bypass contactor in off-state.
Preferably, described malfunction comprise blown fuse, open circuit or isolating transformer fault in any.
With respect to prior art, adopt frequency-converter device of the present invention and method, greatly improved the permission failure rate of whole system.And when breaking down, system is carrying row entirely, without falling to hold, use.
Accompanying drawing explanation
Fig. 1 is six grades of unit series connection type high voltage frequency convertor voltage stacking charts;
Fig. 2 is the main circuit topology figure of high frequency transformer shown in existing techniques in realizing Fig. 1;
Fig. 3 is the structural representation of implementing unit bypass in prior art;
Fig. 4 is the frequency changer schematic diagram of one embodiment of the invention;
Fig. 5 is the main circuit topology figure that realizes the frequency converter shown in Fig. 4;
Fig. 6 is the frequency changer schematic diagram of the another kind of embodiment of the present invention;
Fig. 7 is the main circuit topology figure of frequency converter that realizes an embodiment of frequency changer shown in Fig. 6;
Fig. 8 is the voltage stacking chart of nine grades of unit series connection type high voltage frequency convertors shown in Fig. 7;
Fig. 9 is the flow chart of frequency converter control method of the present invention.
Embodiment
Frequency converter of the present invention comprises power cell, isolating transformer, high-voltage switch gear, bypass contactor.Wherein, the number of power cell is N, and the number of isolating transformer is X, and the number of high-voltage switch gear is also X, and N, X, N/X are positive integer, and X > 1.
Power cell is also referred to as power model, and power cell can be realized by AC-DC-AC single phase inverter circuit, and rectification side is diode three phase full bridge, by IGBT inverter bridge is carried out to sine pulse width modulation (PWM) control, can obtain single phase alternating current (A.C.) output.Each power cell is in full accord in structure and electric property, can exchange.
Because the secondary side of isolating transformer is not connected to the ground, between secondary side and ground, there is no potential difference, therefore use safety.In the present invention, can adopt any applicable transformer, the isolating transformer that for example turn ratio is 1: 1.
High-voltage switch gear typically refer to for voltage 3kV and more than, the alternating-current switch equipment moving in 50 hertz of frequencies and following electric power system, for example air switch, vacuum switch etc.Described high-voltage switch gear is used for connecting isolating transformer and high voltage bus, and each isolating transformer is connected with high voltage bus by a high-voltage switch gear;
Bypass contactor can adopt such as switch elements such as vacuum switches.Described bypass contactor is for carrying out bypass to a described N/X power cell.A described N/X power cell two ends bypass contactor in parallel.
Wherein, by power cell and corresponding isolating transformer, form a plurality of groupings, the number of the power cell in each grouping is identical, and for example the power cell number in each grouping is N/X, between described power cell, connects.
In each grouping, have an isolating transformer, by this isolating transformer, the power cell being together in series is connected with high voltage source bus, forms three-phase voltage source.Power cell with " Y " type connection is connected with three buses of three-phase alternating-current supply respectively, the power cell of the series connection being connected with every bus is N/3, described N the power cell being together in series is divided into X group, N/X in an every group power cell is connected with bus by an isolating transformer, an every N/X power cell two ends bypass contactor in parallel, so that when the power cell of every group or corresponding isolating transformer are normally worked, described bypass contactor disconnects; When the power cell in a group is wherein when maybe this is organized corresponding isolating transformer and breaks down, bypass contactor is closed, so that major loop is communicated with.Wherein, N, X, N/X are positive integer.
Fig. 4 is the frequency changer schematic diagram of one embodiment of the invention.As shown in the figure, what for example, be connected with high voltage bus (the 6kV bus in figure) is two branch roads, on each branch road, be respectively provided with high-voltage switch gear DL1, a DL2, each high-voltage switch gear connects an isolating transformer, each isolating transformer is connected with one group of power cell in unit cabinet, in unit cabinet, be provided with many group power cells, the power cell number in every group of power cell is identical.In unit cabinet, the output of power cell is connected with the motor of carrying out respective drive function.
The primary side of isolating transformer is connected with 6kV high voltage bus, and secondary side is connected with power cell.In the present embodiment, secondary side is connected with power cell by reactor; In other embodiments, if described frequency converter is General Converters, the secondary side of isolating transformer is directly connected with power cell.The output of power cell for example, is connected with corresponding final controlling element (motor).If described frequency converter is vector-control frequency converter, between every group of tap and each power cell, a reactor can be set.
As shown in the figure, power source bus is 6kV electrical network bus, frequency converter VFD (VariableFrequency Drive in figure, be vector type or General Converters) comprise the first isolating transformer 41, the second isolating transformer 42, a plurality of power cell 40, in the present embodiment, the number of power cell 40 is 18.18 power cells with " Y " type connection is connected with three buses of three-phase alternating-current supply respectively, the power cell being connected with every bus is six, described six power cells are divided into two groups, and three power cells in every group are connected with bus by an isolating transformer.In addition, DL1 is the high-voltage switch gear for the first isolating transformer power supply, and DL2 is the high-voltage switch gear for the second isolating transformer power supply.
18 power cells 40 are arranged in unit cabinet, and the high-voltage switch gear that often communicated of three-phase high-voltage bus is connected with six unit, i.e. A A1-A6 unit, B B1-B6 unit, the C C1-C6 unit that is connected that is connected that is connected.The output of frequency converter VFD connects motor 43 by exporting copper bar.
Fig. 5 is the major loop topological diagram of the frequency converter VFD shown in Fig. 4.The secondary winding of the first isolating transformer 41 has nine groups of taps, every group of tap output three-phase voltage, 580VAC for example, be responsible for A4-A6, B4-B6, C4-C6 totally nine unit power supplies, the secondary winding of the second isolating transformer 42 is totally nine groups of taps, in the present embodiment, and the three-phase voltage of every group of tap output, for example 580VAC, is responsible for A1-A3, B1-B3, C1-C3 totally nine power cell power supplies.
A side of A1, B1, C1 forms neutral point, and opposite side and other units in series, finally connect output by A6, B6, C6, for example, export copper bar, and then connects motor 43.In figure, connect a reactor 44 before each unit, load and the filter element of described reactor during as energy feedback.
Bypass contactor KM1, KM2 are connected in parallel on respectively three power cell two ends of every phase.Particularly, KM1 is high-pressure vacuum contactor, and the suitable for reading and end opening of KM1 is connected respectively the both sides of nine unit of A1-A3, B1-B3, C1-C3, for example: the first control line A of KM1 shown in Fig. 5 is connected to the two ends of A1-A3; Second control line B is connected to the two ends of B1-B3; The 3rd control line C is connected to the two ends of C1-C3.Once certain in these nine unit is out of order or the second isolating transformer 2 breaks down, A1-A3, B1-B3, C1-C3 stop output and make high-voltage switch gear DL2 tripping operation disjunction high pressure simultaneously, rapid closing KM1, makes A4-A6, B4-B6, these nine unit of C4-C6 continue the full Half Speed operation of carrying.By application of frequency converter in driving the mine operational environment of elevator cage, these nine unit that entirely carry Half Speed operation continue elevator cage to promote, to pull out the well head of work.In like manner, KM2 can be and the high-pressure vacuum contactor of KM1 same type that the suitable for reading and end opening of KM2 is connected respectively the both sides of nine unit of A4-A6, B4-B6, C4-C6, for example: the first control line A of KM2 shown in Fig. 5 is connected to the two ends of A4-A6; Second control line B is connected to the two ends of B4-B6; The 3rd control line C is connected to the two ends of C4-C6.Once certain in these nine unit is out of order or isolating transformer 1 breaks down, A4-A6, B4-B6, C4-C6 stop output, make high-voltage switch gear DL1 tripping operation disjunction high pressure, rapid closing KM2, makes nine unit of A1-A3, B1-B3, C1-C3 continue the full Half Speed operation of carrying simultaneously.
Fig. 6 is the frequency changer schematic diagram of an alternative embodiment of the invention.As shown in the figure, what be connected with 6kV bus is three branch roads, on each branch road, be respectively provided with high-voltage switch gear DL1, a DL2, DL3, each high-voltage switch gear connects an isolating transformer 61,62,63, each isolating transformer is connected with one group of power cell 60 in unit cabinet, in unit cabinet, be provided with three groups of power cells, the power cell number in every group of power cell is identical.In unit cabinet, the output of power cell is connected with the motor 64 of carrying out respective drive function.
In Fig. 7, show the main circuit topology figure that realizes frequency changer shown in Fig. 6.Wherein, frequency converter comprises 27 power cells, the first isolating transformer 61, the second isolating transformer 62, the 3rd isolating transformer 63, wherein, 27 power cells are connected with three buses of three-phase alternating-current supply respectively with " Y " type connection, the power cell being connected with every bus is nine, described nine power cells are divided into three groups, nine power cells in every group are connected with bus by an isolating transformer, that is, A1-A3, B1-B3, C1-C3 are connected with bus by the first isolating transformer 61; A4-A6, B4-B6, C4-C6 are connected with bus by the second isolating transformer 62; A7-A9, B7-B9, C7-C9 are connected with bus by the 3rd isolating transformer 63.When certain power cell in a certain group breaks down, stop the output of nine power cells in this group, corresponding high-voltage switch gear closed action in parallel, and disconnect this and organize being connected of corresponding bypass contactor and power source bus.
Fig. 8 is the voltage stacking chart of nine grades of unit series connection type high voltage frequency convertors shown in Fig. 7.Be similar to Fig. 1, every power cell that has mutually nine series connection, can obtain-6kV-0-6kV is totally 13 different electric pressures.
The present invention takes full advantage of the advantage of this units in series mode frequency converter, that is:, because unit has rectification characteristic, so input only need meet voltage phase sequence and amplitude, require.In an embodiment of the present invention; for example; isolating transformer is split into two; system is divided into two parts, the system of 18 power cells of take is example, and the number of each half-cell is nine; this " large bypass " scheme of two high-pressure vacuum contactors of utilizing has improved " the permission failure rate " of whole system; under the topological structure of prior art main circuit, once there is heavy fault, just must shut down, can think that so " permission failure rate " is 0%.The present embodiment can be promoted to 50% by " permission failure rate ".Again for example, the system of 27 power cells of take is example, if system is divided into three parts, every a part of unit number is nine, and " permission failure rate " is 66.6% so.If system is divided into X part, every a part of unit number is N/X (N is total unit number, and X is isolating transformer number), and the calculating of its " permission failure rate " can be analogized by above-mentioned algorithm.The topological structure mode that the present invention proposes, is applicable to the products such as universal frequency converter, vector control energy feedback frequency converter.
Correspondingly, the invention provides a kind of control method for above-mentioned frequency converter, the flow chart of described method as shown in Figure 9.The structure similar of described frequency converter and above-mentioned frequency converter, that is, comprising: power cell, isolating transformer, bypass contactor and high-voltage switch gear.Wherein: the number of power cell is N; The number of bypass contactor is X; The number of high-voltage switch gear is X, and N, X, N/X are positive integer, and X > 1.
Described power cell connects with " Y " type connection, and the input of power cell is connected with the secondary side of isolating transformer, the neutral ground that " Y " type connects, the three-phase that " Y " type connects is connected with three-phase high-voltage bus respectively, and the power cell being connected with every phase high voltage bus forms by N/3 power unit cascade.
Described isolating transformer is used for connecting high voltage bus and power cell, a described N power cell is divided into X group, every group comprises N/X power cell, a described N/X power cell comprises the power cell being evenly distributed in three-phase, every individual power cell of N/ (3 * X) that comprises mutually, the power cell of the N/X in every group is connected with the input of power cell by an isolating transformer.
Described high-voltage switch gear is used for connecting isolating transformer and high voltage bus, and each isolating transformer is connected with high voltage bus by a high-voltage switch gear.
Described bypass contactor is for carrying out bypass to a described N/X power cell, a bypass contactor of described N/X power cell two ends parallel connection, and when the power cell of every group or corresponding isolating transformer are normally worked, bypass contactor is in off-state; When wherein the power cell of a group or corresponding isolating transformer break down, bypass contactor is closed, and the high-voltage switch gear between corresponding isolating transformer and high voltage bus disconnects simultaneously.
Described method comprises: in step 701, detect the operating state of each power cell and corresponding isolating transformer, described operating state comprises normal operating conditions and malfunction, and described malfunction may be caused by many reasons, such as: blown fuse, open circuit or isolating transformer fault etc.Described detecting step can be completed by the detecting element being applicable to, for example, and galvanometer, potentiometer etc.By detection power unit and accordingly electric current, the voltage of isolating transformer directly or indirectly, determine the operating state of power cell and corresponding isolating transformer.
In step 702, described operating state is judged.When operating state is normal operating conditions, in step 703, when the power cell of every group or corresponding isolating transformer are normally worked, keep bypass contactor in off-state.
When operating state is fail operation state, in step 704 and 705, respectively the high-voltage switch gear of connection bus and corresponding isolating transformer is disconnected and closed corresponding bypass contactor.For example, as shown in Figure 4,5, when A4 power cell fault being detected, the high-voltage switch gear DL2 of connection bus and corresponding isolating transformer is disconnected, and closed corresponding bypass contactor KM2.And for example, when the first isolating transformer 41 fault being detected, the high-voltage switch gear DL1 of connection bus and corresponding isolating transformer is disconnected, and closed corresponding bypass contactor KM1.
The opening circuit of the detection of fault, corresponding component, closure can realize by Centralized Controller, described Centralized Controller comprises corresponding software module or hardware control logic, and those skilled in the art can realize by any applicable software program method and analog circuit, digital circuit design method.
To the control of frequency converter, can be controlled by Centralized Controller, the various controllers that this Centralized Controller can adopt those skilled in the art to be familiar with, no longer elaborate at this.
Although the present invention is described by above-mentioned preferred embodiment, its way of realization is not limited to the above embodiments.Should be realized that in the situation that not departing from purport of the present invention, those skilled in the art can make different variations and modification to the present invention.
Claims (10)
1. a frequency converter, is characterized in that, described frequency converter comprises power cell, isolating transformer, bypass contactor and high-voltage switch gear, wherein: the number of power cell is N; The number of bypass contactor is X; The number of high-voltage switch gear is X, and N, X, N/X are positive integer, and X > 1,
Described power cell connects with " Y " type connection, and the input of power cell is connected with the secondary side of isolating transformer, the neutral ground that " Y " type connects, the three-phase that " Y " type connects is connected with three-phase high-voltage bus respectively, and the power cell being connected with every phase high voltage bus forms by N/3 power unit cascade;
A described N power cell is divided into X group, every group comprises N/X power cell, a described N/X power cell comprises the power cell being evenly distributed in three-phase, every N/(3 * X that comprises mutually) individual power cell, in each group, there is an isolating transformer, by this isolating transformer, the power cell of the N/X in every group, by being connected with high voltage bus, forms three-phase voltage source;
Described high-voltage switch gear is used for connecting isolating transformer and high voltage bus, and the primary side of each isolating transformer is connected with high voltage bus by a high-voltage switch gear, and secondary side is connected with a power cell;
Described bypass contactor all belongs to frequency converter internal component, for N/X the power cell to every group, carry out bypass, a described N/X power cell two ends bypass contactor in parallel, when the power cell of every group or corresponding isolating transformer are normally worked, bypass contactor is in off-state; When wherein the power cell of a group or corresponding isolating transformer break down, bypass contactor is closed, and the high-voltage switch gear between corresponding isolating transformer and high voltage bus disconnects simultaneously.
2. frequency converter according to claim 1, is characterized in that, N is that 18, X is 2, and described frequency converter comprises 18 power cells, the first isolating transformer, the second isolating transformer,
Wherein, described power cell connects with " Y " type connection, and the input of power cell is connected with the secondary side of isolating transformer, the neutral ground that " Y " type connects, the three-phase that " Y " type connects is connected with three-phase high-voltage bus respectively, is six power unit cascades forms with the power cell being often connected; Described isolating transformer is used for connecting high voltage bus and power cell, described 18 power cells are divided into two groups, every group comprises nine power cells, described nine power cells comprise the power cell being evenly distributed in three-phase, often comprise mutually three power cells, nine power cells in every group are connected with the input of power cell by an isolating transformer.
3. frequency converter according to claim 1, is characterized in that, N is that 27, X is 3, and described frequency converter comprises 27 power cells, the first isolating transformer, the second isolating transformer, the 3rd isolating transformer,
Wherein, described power cell connects with " Y " type connection, and the input of power cell is connected with the secondary side of isolating transformer, the neutral ground that " Y " type connects, the three-phase that " Y " type connects is connected with three-phase high-voltage bus respectively, is nine power unit cascades forms with the power cell being often connected; Described isolating transformer is used for connecting high voltage bus and power cell, described 27 power cells are divided into three groups, every group comprises nine power cells, described nine power cells comprise the power cell being evenly distributed in three-phase, often comprise mutually three power cells, nine power cells in every group are connected with the input of power cell by an isolating transformer.
4. frequency converter according to claim 1, it is characterized in that, described frequency converter is vector-control frequency converter, described vector-control frequency converter also comprises the reactor being connected between each power cell and corresponding isolating transformer, load and the filter element of described reactor during as energy feedback.
5. for a control method for frequency converter, described frequency converter comprises power cell, isolating transformer, bypass contactor and high-voltage switch gear, wherein: the number of power cell is N; The number of bypass contactor is X; The number of high-voltage switch gear is X, N, X, N/X are positive integer, and X > 1, described power cell connects with " Y " type connection, and the input of power cell is connected with the secondary side of isolating transformer, the neutral ground that " Y " type connects, the three-phase that " Y " type connects is connected with three-phase high-voltage bus respectively, is N/3 power unit cascade forms with the power cell being often connected; A described N power cell is divided into X group, every group comprises N/X power cell, a described N/X power cell comprises the power cell being evenly distributed in three-phase, every N/(3 * X that comprises mutually) individual power cell, in each group, there is an isolating transformer, by this isolating transformer, the power cell of the N/X in every group, by being connected with high voltage bus, forms three-phase voltage source; Described high-voltage switch gear is used for connecting isolating transformer and high voltage bus, and the primary side of each isolating transformer is connected with high voltage bus by a high-voltage switch gear, and secondary side is connected with a power cell; Described bypass contactor all belongs to frequency converter internal component, for the power cell of the N/X to every group, carries out bypass, a described N/X power cell two ends bypass contactor in parallel,
It is characterized in that, said method comprising the steps of:
A. detect the operating state of respectively connect power cell and corresponding isolating transformer;
B. when wherein the operating state of the power cell of a group or isolating transformer is malfunction, the bypass contactor of closed and the power cell parallel connection of connecting of breaking down, simultaneously by the high-voltage switch gear disconnection between corresponding isolating transformer and high voltage bus.
6. method according to claim 5, it is characterized in that, described frequency converter comprises 18 power cells, the first isolating transformer, the second isolating transformer, wherein, described power cell connects with " Y " type connection, and the input of power cell is connected with the secondary side of isolating transformer, the neutral ground of " Y " type connection, the three-phase that " Y " type connects is connected with three-phase high-voltage bus respectively, is six power unit cascades forms with the power cell being often connected; Described isolating transformer is used for connecting high voltage bus and power cell, described 18 power cells are divided into two groups, every group comprises nine power cells, described nine power cells comprise the power cell being evenly distributed in three-phase, often comprise mutually three power cells, nine power cells in every group are connected with the input of power cell by an isolating transformer.
7. method according to claim 5, it is characterized in that, described frequency converter comprises 27 power cells, the first isolating transformer, the second isolating transformer, the 3rd isolating transformer, wherein, described power cell connects with " Y " type connection, and the input of power cell is connected with the secondary side of isolating transformer, the neutral ground that " Y " type connects, the three-phase that " Y " type connects is connected with three-phase high-voltage bus respectively, is nine power unit cascades forms with the power cell being often connected; Described isolating transformer is used for connecting high voltage bus and power cell, described 27 power cells are divided into three groups, every group comprises nine power cells, described nine power cells comprise the power cell being evenly distributed in three-phase, often comprise mutually three power cells, nine power cells in every group are connected with the input of power cell by an isolating transformer.
8. method according to claim 5, it is characterized in that, in step a, by galvanometer, potentiometer, detect electric current, the voltage of detection power unit and corresponding isolating transformer, to detect the operating state of respectively connect power cell and corresponding isolating transformer.
9. method according to claim 5, is characterized in that, step b also comprises: when the power cell of every group or corresponding isolating transformer are normally worked, keep bypass contactor in off-state.
10. method according to claim 5, is characterized in that, described malfunction comprises blown fuse, open circuit or isolating transformer fault in any.
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| CN103701335A (en) * | 2013-12-31 | 2014-04-02 | 天安电气集团浙江电气有限公司 | High-voltage inverter power unit system |
| CN107911030B (en) * | 2017-11-21 | 2019-12-06 | 北京合力电气传动控制技术有限责任公司 | high-voltage frequency conversion multi-machine transmission system and offshore platform comprehensive oil production system |
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| 中压变频器的技术特性及运用;何丽梅等;《天然气与石油》;20080430;第26卷(第2期);27-32 * |
| 何丽梅等.中压变频器的技术特性及运用.《天然气与石油》.2008,第26卷(第2期),第27-32页. |
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