CN201937279U - Isolated static var generator of transformer - Google Patents

Isolated static var generator of transformer Download PDF

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Publication number
CN201937279U
CN201937279U CN2011200777233U CN201120077723U CN201937279U CN 201937279 U CN201937279 U CN 201937279U CN 2011200777233 U CN2011200777233 U CN 2011200777233U CN 201120077723 U CN201120077723 U CN 201120077723U CN 201937279 U CN201937279 U CN 201937279U
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transformer
current
voltage
module
converter cell
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王卫安
黄燕艳
谭胜武
周方圆
蔡蔚
张定华
王才孝
龙礼兰
邱文俊
朱建波
周靖
刘华东
胡晓东
余军
吴选保
胡前
李青山
莫添珍
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Zhuzhou National Engineering Research Center of Converters Co Ltd
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Zhuzhou National Engineering Research Center of Converters Co Ltd
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    • 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
    • Y02E40/00—Technologies for an efficient electrical power generation, transmission or distribution
    • Y02E40/10—Flexible AC transmission systems [FACTS]
    • 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
    • Y02E40/00—Technologies for an efficient electrical power generation, transmission or distribution
    • Y02E40/40—Arrangements for reducing harmonics

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Abstract

The utility model discloses an isolated static var generator of a transformer, which comprises current transformers, voltage transformers, a boosting transformer, a SVG (static var generator) starting device, an RC (Resistance-Capacitance) filtering branch, module current transformers, an output reactor and a converter unit; no less than two output ends of the converter unit are connected with the output reactor; higher harmonics are filtered out by the RC filtering branch; after passing through the SVG starting device composed of an output end resistor and a contactor, the various outputs of the converter unit are in parallel connection at a low-voltage busbar to be combined into joint current; then the voltage is boosted to the power grid voltage by the boosting transformer; various modules are connected with the module current transformers; the low-voltage busbar is connected with the low-voltage side voltage transformer and the current transformer; and a high-voltage busbar is connected with the power grid side voltage transformer and the current transformer. The static var generator has increased output current and SVG volume, thereby achieving the capability of filtering the higher harmonics, and lifting the system redundancy.

Description

A kind of transformer isolation stillness wattless occurrence apparatus
Technical field
The utility model relates to a kind of power quality controlling device, especially relates to a kind of multipleization of transformer isolation type boost type phase shift stillness wattless occurrence apparatus, is widely used in all kinds of electric power systems.
Background technology
Along with the high speed development of Chinese national economy, perception and nonlinear load constantly increase in the electrical network, as: rectifier, asynchronous machine and arc furnace etc., the continuous access of these loads make that the electrical network quality of power supply continues to worsen.In the mine, industrial load such as metallurgy, harbour and petrochemical industry.
The main way of power quality problem that solves present electrical network is that devices such as FC, TSC or TCR are installed.FC is fixedly reactive power compensation, can cross when the idle variation of load and mend and owe to mend, and FC is passive filtering that filter effect is limited, and is indifferent to high harmonic inhibition; TSC is the capacitance grading switching, though can be according to the idle size variation of load, it is to have level to regulate, and can not the Continuous Tracking load variations, and is similarly passive filtering, filter effect is limited; TCR adopts Controlled Reactor to add the FC mode, though can regulate compensation capacity continuously according to load variations, the TCR response time is longer, and if the twice of the installation of TCR Controlled Reactor, the general compensation capacity of capacity, floor space is big.In addition, TCR also can inject low-order harmonic to electrical network.
The power quality controlling device of Cai Yonging mainly contained FC, TSC and TCR in the past, and these controlling devices have many shortcomings, as: no real-time tracking load variations, big, the harmonic wave inhibition ability of floor space.And SVG can follow the tracks of the idle and harmonic wave variation of load continuously dynamically, has very desirable regulation effect, and floor space only is about 1/3rd of TCR or TSC.But SVG need adopt full control device IGBT, and the unsteady flow module of single high-power IGBT is withstand voltage limited, and its capacity is too little for the application of megavolt-ampere level.And because the IGBT switching frequency is subjected to the restriction of device its own switch upper frequency limit, be generally about 1kHz～3kHz under the large-power occasions, the harmonic wave that SVG current transformer self is produced is bigger, causes THD to surpass GB GB/T14549-93 " quality of power supply utility network harmonic wave " requirement.
And adopt the complete idle and harmonic wave of SVG energy real-time tracking load of controlling device IGBT, can also be applied to suppress simultaneously flickering and electric voltage dropping.But because the Power Limitation of single IGBT module, the capacity of the SVG of present single IGBT unsteady flow module is difficult to adapt to industrial application requirements, therefore generally adopts the mode of serial or parallel connection to improve the current transformer capacity, and following patent application and this programme are close.
1, prior art 1 is in application on 06 12nd, 2003 by Tsing-Hua University, on December 10th, 2003 is open, publication number is that the Chinese utility application " reversible transducer that is used for the control of chain static synchronous compensator dc-voltage balance " of CN1461088A mainly is to adopt by two dividing potential drop electric capacity, direct voltage is divided into half, adopt single-phase H bridging parallel operation, by the square wave " be coupled into an alternating voltage export " of three-winding transformer with two single-phase H bridging parallel operation outputs.The square wave inversion that this scheme adopts, cause transformer saturated easily, though by isolation capacitance isolated DC electric current, but increased the complexity of circuit like this, and the low-order harmonic content of square wave inversion is big, the filtering difficulty, be difficult to meet the requirement of electrical network to total harmonic distortion, and be to adopt the multi winding transformer series system, its transformer is made difficulty, cost height.This scheme has proposed series connection dividing potential drop electric capacity DC side dividing potential drop according to the problem of present SVG capacity; this project organization effect of isolating capacitor is that the protection transformation is unsaturated because of direct current biasing; the square-wave voltage of double convertor is coupled into an alternating voltage by three-winding transformer, and this technology can be used for the unit module of connecting among the tandem type SVG.The shortcoming of this method is, its square wave inversion design is not owing to adopt the PWM technology, and output low-order harmonic content is big, be difficult to adapt to the requirement of output harmonic wave content, three-winding transformer not only takes up an area of big when a plurality of series connection are used, and manufacture difficulty is big, the production cost height.
2, prior art 2 is to be applied on 03 16th, 2005 by Liu Wenhui and Liu Wenhua, on 07 19th, 2006 open, publication number is that the Chinese utility model patent " a kind of main circuit of transformer isolation type stillness wattless occurrence apparatus " of CN2798390 mainly is to adopt H bridge outlet side to isolate the mode that dc bus capacitor is connected in parallel through the multi winding transformer series connection.This technology is by the many windings in series of Circuit Fault on Secondary Transformer, and it is synthetic to make primary side induce voltage, and this and prior art 1 are similar.This mode remains the principle based on multi winding transformer series coupled voltage, does not use isolating capacitor, is more suitable for adopting the static reacance generator of PWM modulation system.This scheme adopts multi winding transformer to isolate, and to primary side, makes output voltage be improved the voltage coupling overlapped in series of a plurality of H bridging of secondary side parallel operation, and under the certain situation of electric current, the SVG capacity is improved.There is shortcoming in this technology: the multi winding transformer complex structure breaks down easily, make difficulty, cost an arm and a leg, account for 1/2～1/3 of SVG manufacturing cost, the multi winding transformer floor space is far longer than common transformer, it is nearly 50% to adopt this kind transformer loss to increase, and the ferromagnetic nonlinear characteristic of this kind transformer has also been brought a lot of troubles to Control System Design.
3, prior art 3 is in application on 09 01st, 2005 by Shanghai Communications University, on 02 22nd, 2006 open, publication number is that the Chinese utility application " single-phase transformer four-layer IGBT type dynamic reactive compensator " of CN1738144A is at single phase circuit, proposition is in the mode of inversion outlet side series connection, the inversion outlet side adopts the multi winding transformer series connection to isolate the dc capacitor parallel connection of quadruple current transformer.The shared one group of dc capacitor of the current transformer of three phases was consistent with " a kind of main circuit of transformer isolation type stillness wattless occurrence apparatus " when its technology was applied to three-phase circuit.This scheme is based on the principle of multi winding transformer series coupled voltage equally, and different is that this scheme is primarily aimed at single phase circuit.The problem that this scheme promotes at the SVG capacity, its method is single-phase multi winding transformer overlapped in series small-power current transformer voltage, makes output voltage be improved, the SVG capacity is improved.This kind method inevitably will be used multi winding transformer, and the shortcoming of this transformer makes the efficient of SVG reduce and the cost increase, is unfavorable for the large-scale engineering application of SVG.
4, prior art 4 is in application on 07 31st, 2004 by the Central China University of Science and Technology, on 03 02nd, 2005 open, publication number is that the Chinese utility model patent " a kind of big capacity static reacance generator " of CN1588745A is at high-power reactive power compensation, propose static reacance generator and adopt multi winding transformer to isolate, again according to the electric current of required compensation N winding injecting reactive current at the secondary side of multi winding transformer.This scheme is based on the principle of multi winding transformer series coupled voltage equally, and what difference was this scheme proposition is N winding, unqualified winding quantity.This scheme adopts multi winding transformer to isolate, and injects the required reactive current of compensation in its N winding, thereby realizes the lifting of SVG.
5, prior art 5 is in application on 08 14th, 2009 by Beijing Siyuan Qingneng Electrical ﹠ Electronic Co., Ltd, Tsing-Hua University, on 01 06th, 2010 open, publication number is STATCOM and the static reacance generator of the Chinese utility application " controller of high-voltage chain type static and synchronous compensator " of CN 101621202A at chain structure, has proposed a kind of digitial controller of high-voltage chain type structure.This scheme is a controller at multi winding transformer isolation chain static reacance generator, and what mainly solve is the control hardware circuit design problem of chain static reacance generator.This scheme is the demand for control according to chain structure transformer isolation type SVG, has proposed a kind of control hardware design, and this scheme is applicable to chain structure, and is confined to the hardware control system design content.
6, prior art 6 is in application on 08 02nd, 2005 by Xi'an Saibo Electric Co., Ltd, on 09 27th, 2006 open, publication number is that the Chinese utility model patent " Active Power Filter-APF of multipleization circuit structure and control method " of CN2821993 has proposed a kind of parallel-connection multiple circuit structure at active filter, this structure is by the multiple equivalent switching frequency that improved of phase shift, makes APF can export big electric current and obtains better harmonic compensation effect.This scheme adopts CPS SPWM mode, makes double 180 ° the phase place that staggers, this scheme control at be harmonic wave control, the shared same group of energy storage DC link of its whole modules.Scheme adopts main circuit mode in parallel, and all the shared energy-storage units of current transformer is controlled and adopted DFT harmonic current algorithm and CPS-SPWM modulation system.There is following limitation in this kind method, at first, the control of this scheme adopts the DFT algorithm can not be applicable to the idle detection of load, not having the control corresponding method to control each heavy current transformer reasonably distributes idle, each heavy reactive current of being sent does not mend or owes to mend as if there being reasonable distribution can cause not having merits and demerits, thereby influences the SVG compensation performance; Secondly, because each does not heavily adopt independently energy storage dc capacitor, if wherein a heavy current transformer damages, need all modules are out of service, all contactor trippings, and shared electric capacity electric weight consumed by discharge resistance, and before the current transformer that more renews, adopt the SVG of this scheme to work on, this not only makes the SVG reliability decrease, and the elongated maintenance of breakdown maintenance time is difficult more.
The utility model content
The purpose of this utility model provides a kind of parallel-connection multiple current transformer, total output current is got a promotion, boost by transformer isolation then, make the transformer isolation stillness wattless occurrence apparatus of output voltage lifting consumer networks voltage, it is low to solve high-power SVG switching frequency, the power output deficiency, current transformer reliability decrease that DC side does not independently cause between current transformer and damage equipment are changed the technical problem of inconvenience.
The utility model specifically provides a kind of embodiment of transformer isolation stillness wattless occurrence apparatus, a kind of transformer isolation stillness wattless occurrence apparatus, comprise: current transformer, voltage transformer, step-up transformer, the SVG starting drive, the RC filter branch, the blocks current instrument transformer, out put reactor and converter cell, be no less than double converter cell output and connect out put reactor, out put reactor is used to suppress near the harmonic current of converter switches frequency, the out put reactor output current is through RC filter branch elimination high order harmonic component, again through behind the SVG starting drive that constitutes by output resistance and contactor, the output of each heavy converter cell is in the parallel connection of low-voltage bus bar place, by step-up transformer voltage is risen to line voltage after the synthetic total current, each module is connected with the blocks current instrument transformer, on low-voltage bus bar, be connected with low-pressure side voltage transformer and low-pressure side current transformer, on high voltage bus, be connected with grid side voltage transformer and grid side current transformer.
As the further execution mode of a kind of transformer isolation stillness wattless occurrence apparatus of the utility model, be no less than double converter cell and adopt identical structure, converter cell comprises dc capacitor and semiconductor variable parallel operation, dc capacitor is connected in parallel on the two ends of semiconductor variable parallel operation, and the semiconductor variable parallel operation is to be no less than two the half-bridge circuit half bridge circuit that forms in parallel.
As the further execution mode of a kind of transformer isolation stillness wattless occurrence apparatus of the utility model, the transformer isolation stillness wattless occurrence apparatus comprises control device, control device comprises signal acquisition module, idle computing module, idle distribution module, two closed-loop control modules and modulation module, signal acquisition module is gathered high side voltage and current signal by grid side voltage transformer and grid side current transformer, idle computing module is according to the voltage and current signal that collects, calculate the reactive current that SVG should compensate in real time, give each converter cell by idle distribution module by two closed-loop control modules and modulation module mean allocation again.
As the further execution mode of a kind of transformer isolation stillness wattless occurrence apparatus of the utility model, control module includes power control system link, idle controlling unit and dq transform part, meritorious controlling unit is two close-loop feedback control links, comprise ring and Voltage Feedback outer shroud in the current feedback, dc voltage u DcFeed back to control module and constitute Voltage Feedback outer shroud, active current i dFeedback adds pi regulator and constitutes ring in the current feedback; Idle controlling unit is current closed-loop control, distributes to the idle amount Q of converter cell 1Through proportional component K, produce reactive component of current reference signal i Qr, feedback signal is converter cell reactive component of current i qFeedback signal is through regulating through the PI controlling unit after relatively with reference signal, and the signal after the correction is changed to three-phase signal through the contravariant of dq transform part, and then relatively modulates by modulation module with the phase shift triangular wave, export to converter module at last, make converter module output three-phase current.
As the further execution mode of a kind of transformer isolation stillness wattless occurrence apparatus of the utility model, the tuple of converter cell is a quadruple, and described semiconductor variable parallel operation comprises four half-bridge circuits in parallel.
As the further execution mode of a kind of transformer isolation stillness wattless occurrence apparatus of the utility model, modulation module adopts the CPS-SPWM modulating mode, when the quadruple converter cell is in parallel, and the CPS-SPWM signal of the every heavy converter cell 90 ° of phase places that stagger successively.
As the further execution mode of a kind of transformer isolation stillness wattless occurrence apparatus of the utility model, be no less than the shared control device of double converter cell.
A kind of embodiment of the method that the transformer isolation stillness wattless occurrence apparatus is controlled, a kind of transformer isolation stillness wattless occurrence apparatus control method may further comprise the steps:
A. the signal acquisition module of control device is gathered high side voltage and current signal by grid side voltage transformer and grid side current transformer;
B. idle computing module calculates the reactive current that SVG should compensate in real time according to the voltage and current signal that collects;
C. idle distribution module is given each converter cell with the reactive current value that SVG should compensate as the referenced reactive current value mean allocation of converter cell;
D. control module is according to dc voltage u DcValue of feedback is distributed to the idle amount Q of converter cell 1In conjunction with meritorious current component i dWith converter cell reactive component of current i q, through the signal behind the output calibration after the control, contravariant is changed to three-phase current signal through dq again;
E. three-phase current signal and phase shift triangular wave relatively carry out the CPS-SPWM modulation, and the CPS-SPWM modulation signal is exported to converter cell, make converter cell output three-phase current.
As the further execution mode of a kind of transformer isolation stillness wattless occurrence apparatus control method, the control procedure of control module includes power control system process and idle control procedure, and meritorious control procedure adopts two close-loop feedback control modes, dc voltage u DcFeed back to control device and constitute Voltage Feedback outer shroud, active current i dFeedback adds pi regulator and constitutes ring in the current feedback; Idle control procedure adopts current closed-loop control, distributes to the idle amount Q of converter cell 1Through proportional component K, produce reactive component of current reference signal i Qr, feedback signal is the reactive component of current i of converter cell q, feedback signal i qWith reference signal i QrRegulate the signal behind the output calibration relatively through the PI controlling unit.
As the further execution mode of a kind of transformer isolation stillness wattless occurrence apparatus control method, when three-phase current signal and phase shift triangular wave relatively carry out the CPS-SPWM modulation, when the quadruple converter cell is in parallel, the CPS-SPWM signal of every heavy converter cell 90 ° the phase place that staggers successively.
By implementing the embodiment of a kind of transformer isolation stillness wattless occurrence apparatus of the utility model, at main circuit parallel-connection multiple current transformer, total output current is got a promotion, avoided the use multi winding transformer, improved the capacity of SVG.Boost by transformer isolation, make output voltage lifting consumer networks voltage.Simultaneously, not only make SVG possess the more ability of high order harmonic component of filtering, and promoted the redundancy of effort ability of system.
Description of drawings
In order to be illustrated more clearly in the utility model embodiment or technical scheme of the prior art, to do to introduce simply to the accompanying drawing of required use in embodiment or the description of the Prior Art below, apparently, accompanying drawing in describing below only is embodiment more of the present utility model, for those of ordinary skills, under the prerequisite of not paying creative work, can also obtain other accompanying drawing according to these accompanying drawings.
Fig. 1 is the circuit theory diagrams that a kind of transformer isolation stillness wattless occurrence apparatus of the utility model is applied to single phase system;
Fig. 2 is the system configuration composition frame chart of a kind of transformer isolation stillness wattless occurrence apparatus of the utility model control device;
Fig. 3 is system's control principle block diagram of a kind of transformer isolation stillness wattless occurrence apparatus of the utility model control device control module part;
Fig. 4 is the circuit theory diagrams that a kind of transformer isolation stillness wattless occurrence apparatus of the utility model is applied to three-phase system;
Wherein: 20,30,40, the 50-converter cell, 21, the 31-dc capacitor, 22,32-semiconductor variable parallel operation, 23,33,43, the 53-out put reactor, 24,34,44,54-blocks current instrument transformer, 25,35,45, the 55-RC filter branch, the 26-SVG starting drive, the 7-low-voltage bus bar, 8-low-pressure side voltage transformer, 9-low-pressure side current transformer, the 10-step-up transformer, 11-grid side voltage transformer, 12-grid side current transformer, 13-control device, the 14-signal acquisition module, the idle computing module of 15-, the idle distribution module of 16-, 17-control module, the 18-modulation module, the 171-controlling unit of gaining merit, the idle controlling unit of 172-, 173-dq transform part.
Embodiment
Below in conjunction with the accompanying drawing among the utility model embodiment, the technical scheme among the utility model embodiment is clearly and completely described, obviously, described embodiment only is a part of embodiment of the present utility model, rather than whole embodiment.Based on the embodiment in the utility model, those of ordinary skills are not making the every other embodiment that is obtained under the creative work prerequisite, all belong to the scope of the utility model protection.
Embodiment as a kind of transformer isolation stillness wattless occurrence apparatus of the utility model, in order to improve the capacity of SVG, solving the restriction of single converter cell output voltage and electric current, is a kind of exemplary embodiment that the utility model is applied in the transformer isolation stillness wattless occurrence apparatus in the single phase circuit as shown in Figure 1.As shown in Figure 1,20,30,40,50 is converter cell, 21,31 is dc capacitor, 22,32 is semiconductor power device, 23,33,43,53 is out put reactor, 24,34,44,54 is the blocks current instrument transformer, 25,35,45,55 is the RC filter branch, and 26 is the SVG starting drive, and 7 is low-voltage bus bar, 8 is the low-pressure side voltage transformer, 9 is the low-pressure side current transformer, and 10 is step-up transformer, and 11 is the grid side voltage transformer, 12 is the grid side current transformer, and 13 is control device.
Wherein, be example with the first heavy converter cell, 21 is the dc capacitor of converter cell.As can be seen, each heavy current transformer DC side adopts independently dc capacitor, between do not have electrical link.22 is the semiconductor variable parallel operation of current transformer, and the circuit form of semiconductor variable parallel operation is a half bridge circuit, as a kind of preferred implementation, in order to improve output capacity, adopts 4 half-bridge circuit parallel connections in the IPM module.Wherein, but number design capacity in parallel need change use.A module comprises converter cell, out put reactor, blocks current instrument transformer, RC filter branch and SVG starting drive.23 is the out put reactor of each module, and its effect is to suppress near the harmonic current of converter switches frequency.24 is the current transformer of each module, each blocks current of sampling, and current signal passed to control device.5 is the RC filter branches, and its effect is near the harmonic voltage the filtering SVG substance converter switches frequency.6 is the SVG starting drive, and 7 is low-voltage bus bar, and 8 is the low-pressure side voltage transformer of transformer, and 9 is the low-pressure side current transformer of transformer, and 10 is step-up transformer; 11 is the voltage transformer of grid side; 12 is the current transformer of grid side.
Embodiment of the present utility model adopts multiple identical converter cell parallel connection, is the quadruple converter cell shown in Fig. 1.Being not limited to quadruple in actual the use, can be double, triple, also can be that quadruple is above in parallel.Control the certain angle of each module phase-shifting carrier wave by the control device of concentrating, as when adopting quadruple converter cell module in parallel, the CPS-SPWM signal of every heavy converter cell staggers 90 ° successively, and every group of converter cell all has current transformer of oneself and voltage transformer to realize multipleization of phase shift.After the converter cell output connects out put reactor, through RC filter branch elimination high order harmonic component, again through constituting the SVG starting drive by output resistance and contactor, the output of each heavy converter cell is in the place's parallel connection of low-voltage alternating-current bus, the synthetic less total current of low-order harmonic content rises to line voltage to voltage by step-up transformer 10 then.Owing to isolate the electric pressure that has reduced SVG current transformer side through step-up transformer 10, thereby the insulating Design of current transformer cabinet only need be by the low-voltage rating calculation.When the SVG system was short-circuited fault, step-up transformer can suppress short circuit current to a certain extent.
As a kind of typical embodiment, the shared public SVG control device 13 of all converter cells, be controlled to be example with the first heavy A phase current, by gathering the secondary side signal of the mutual CT1A of stream among Fig. 1, give control device the real-time waveform signal feedback of the first A phase current transformer output current that weighs, in order to realize that the first heavy A phase current controls in real time, four current transformers adopt multiple triangular wave phase shifting control, and every heavy current transformer all uses same reactive component of current signal.
As shown in Figure 2, the transformer isolation stillness wattless occurrence apparatus comprises control device 13, control device comprises signal acquisition module 14, idle computing module 15, idle distribution module 16, two closed-loop control modules 17 and modulation module 18, signal acquisition module 14 is gathered high side voltage Us and current signal Is by grid side voltage transformer 11 and grid side current transformer 12, idle computing module 15 is according to the voltage and current signal that collects, use the reactive current extraction algorithm to calculate the reactive current that SVG should compensate in real time, give each converter cell by idle distribution module 16 by two closed-loop control modules 17 and modulation module 18 mean allocation again, as the referenced reactive current value of each converter cell.
Below in conjunction with instantiation control procedure is described below.When SVG has the heavy converter cell of N in parallel, be controlled to be example with the first heavy converter cell, establish that SVG is required to send total idle Q that is SVG, then the first heavy converter cell is actual required sends idle can calculating according to following formula:
Q 1 = Q SVG N
And heavily damaging or when out of service, it is idle constant that other each heavy current transformers are exported, idle being output as that this moment is total in N is heavy:
Q SVG ′ = ( N - 1 ) · Q 1 = N - 1 N · Q SVG
Its output reactive power capability reduces to original (N-1)/N, but not influencing the SVG complete machine works on, and only needs in time to change current transformer or the dc capacitor that damages, and can improve the reliability of SVG.
Control device distribute each heavy converter cell is required send idle size after, the substance converter cell is controlled according to mode shown in Figure 3.Wherein, control module includes power control system link 171, idle controlling unit 172 and dq transform part 173, and meritorious controlling unit 171 is two close-loop feedback control links, comprises ring and Voltage Feedback outer shroud in the current feedback, dc voltage u DcFeed back to control module and constitute Voltage Feedback outer shroud, active current i dFeedback adds pi regulator and constitutes ring in the current feedback; Idle controlling unit 172 is current closed-loop control, distributes to the idle amount Q of converter cell 1Through proportional component K, produce reactive component of current reference signal i Qr, feedback signal is converter cell reactive component of current i qFeedback signal is through regulating through the PI controlling unit after relatively with reference signal, signal after the correction is changed to three-phase signal through 173 contravariant of dq transform part, and then relatively modulate by modulation module with the phase shift triangular wave, the CPS-SPWM signal of the every heavy converter cell certain angle that staggers successively, the angle that staggers successively in the middle of a kind of typical embodiment is 90 °, and the CPS-SPWM modulation signal is exported to the current transformer drive circuit, makes converter module output three-phase current.
The described main circuit scheme of the utility model embodiment can be applied to the heavy converter cell trigger impulse of N phase-shift control mode SVG, by at bus place resultant current, the N that the equivalent synthesising switch frequency that SVG is improved under the situation that does not change the power electronics semiconductor device switching frequency is the substance current transformer doubly, reduce the harmonic content of current transformer self injection electrical network, reduced the harmonic wave that SVG self produces.Simultaneously, the raising of equivalent switching frequency can make SVG possess current tracking ability faster, has improved the SVG dynamic response capability.
Main circuit diagram when Fig. 4 is applied to three-phase system for this programme, the A of every heavy converter cell, B, the shared same direct current of C three-phase unsteady flow module support capacitor system, but the direct current system between each weight is separate.Behind filter reactance, RC filter branch and contactor, the quadruple current transformer inserts high voltage bus by step-up transformer in the place's parallel connection of low-voltage alternating-current bus behind the synthetic equivalent current.
A kind of embodiment of transformer isolation stillness wattless occurrence apparatus control method, this control method may further comprise the steps:
A. the signal acquisition module of control device is gathered high side voltage and current signal by grid side voltage transformer and grid side current transformer;
B. idle computing module calculates the reactive current that SVG should compensate in real time according to the voltage and current signal that collects;
C. idle distribution module is given each converter cell with the reactive current value that SVG should compensate as the referenced reactive current value mean allocation of converter cell;
D. control module is according to dc voltage u DcValue of feedback is distributed to the idle amount Q of converter cell 1In conjunction with meritorious current component i dWith converter cell reactive component of current i q, through the signal behind the output calibration after the control, contravariant is changed to three-phase current signal through dq again;
E. three-phase current signal and phase shift triangular wave relatively carry out the CPS-SPWM modulation, and the CPS-SPWM modulation signal is exported to converter cell, make converter cell output three-phase current.
The control procedure of control module further includes power control system process and idle control procedure, and meritorious control procedure adopts two close-loop feedback control modes, dc voltage u DcFeed back to control device and constitute Voltage Feedback outer shroud, active current i dFeedback adds pi regulator and constitutes ring in the current feedback; Idle control procedure adopts current closed-loop control, distributes to the idle amount Q of converter cell 1Through proportional component K, produce reactive component of current reference signal i Qr, feedback signal is the reactive component of current i of converter cell q, feedback signal i qWith reference signal i QrRegulate the signal behind the output calibration relatively through the PI controlling unit.Wherein, when relatively the CPS-SPWM modulation of three-phase current signal and phase shift triangular wave, be example to adopt the parallel connection of quadruple converter cell module, the CPS-SPWM signal of every heavy converter cell 90 ° the phase place that staggers successively.
The described embodiment of the utility model adopts phase-shifting carrier wave multiple convertor scheme, and converter cell is parallel to low-voltage bus bar through out put reactor earlier, and then the SVG circuit structure that boosts and reach line voltage by step-up transformer.Concrete scheme of the present utility model is not limited to the quadruple mode, can be designed to double, triple or more multiple parallel connection as required.When the technical solution of the utility model was applied to single phase circuit, converter cell adopted single-phase semi-bridge formula circuit, and the DC side of each current transformer has independently direct current capacitor.When the technical solution of the utility model was applied to three-phase system, every heavy converter cell adopted three-phase bridge circuit, the power cell common DC electric capacity of three phases, dc capacitor circuit structure independently between the different converter cells.Each weighs the idle of converter cell module by public control device centralized control, has realized the control mode of total idle mean allocation of SVG.By the heavy converter cell parallel connection of N, make the SVG capacity break through the Power Limitation of single power model, the output current ability increases N times for individual module.Though adopt the chain type SVG of multi winding transformer also can improve power output by the coupled voltages series connection, the multi winding transformer complex structure is made difficulty, and is with high costs.Technical solutions of the utility model adopt multipleization of phase-shifting carrier wave parallel way, can increase the SVG power output, have saved the transformer cost, have reduced the SVG system bulk.Link each heavy converter cell in low-pressure side bus by linking out put reactor, reduce each heavy converter cell causes converter cell to damage because of current unevenness possibility, cooperated suitable control method that the inequality of electric current is controlled in the small range.Connect reactor and when converter cell is short-circuited fault, have the short circuit current of inhibition ability.The design of multiple convertor unit parallel connection can make SVG possess the redundancy backup ability.Every heavy converter cell in the technical solutions of the utility model adopts the three-phase bridge power model, and every heavy converter cell adopts half bridge circuit.Every heavy current transformer dc bus capacitor is separate, can make each molality piece of SVG have independence, promptly when heavy can not an operation wherein, or substance current transformer direct current is when perhaps IGBT damages, can make that state of heavily deactivating that can not move or damage, other current transformers still work on.Power output has only reduced a part, can not cause whole SVG system out of service.Under the situation of the contactor tripping that damages current transformer, can not influence other current transformer work and change the broken parts device.The problem of the saturated damage of multi winding transformer can not appear causing because of indivedual unsteady flow module output current direct current biasings.Can adopt the small-power module to increase the mode of tuple in parallel in the application scenario of middle power, improve synthetic output frequency, reduce the harmonic wave that injects electrical network, and improve the inhibition ability of SVG harmonic wave thereby reach.Simultaneously, converter cell adopts the mode of low pressure parallel connection, has reduced the requirement to apparatus insulated ability.Isolating switch, circuit breaker, filter reactor and cabinet be to selecting according to the requirement of low-voltage, makes the cost of SVG around Berry transformer system greater advantage be arranged more than.
The above only is a preferred implementation of the present utility model; should be pointed out that for those skilled in the art, under the prerequisite that does not break away from the utility model principle; can also make some improvements and modifications, these improvements and modifications also should be considered as protection range of the present utility model.

Claims (7)

1. transformer isolation stillness wattless occurrence apparatus, it is characterized in that: comprise current transformer, voltage transformer, step-up transformer, the SVG starting drive, the RC filter branch, the blocks current instrument transformer, out put reactor and converter cell, be no less than double converter cell output and connect out put reactor, through RC filter branch elimination high order harmonic component, again through behind the SVG starting drive that constitutes by output resistance and contactor, the output of each heavy converter cell is in the parallel connection of low-voltage bus bar place, by step-up transformer voltage is risen to line voltage after the synthetic total current, each module is connected with the blocks current instrument transformer, on low-voltage bus bar, be connected with low-pressure side voltage transformer and low-pressure side current transformer, on high voltage bus, be connected with grid side voltage transformer and grid side current transformer.
2. a kind of transformer isolation stillness wattless occurrence apparatus according to claim 1, it is characterized in that: describedly be no less than double converter cell and adopt identical structure, converter cell comprises dc capacitor and semiconductor variable parallel operation, dc capacitor is connected in parallel on the two ends of semiconductor variable parallel operation, and the semiconductor variable parallel operation is to be no less than two the half-bridge circuit half bridge circuit that forms in parallel.
3. a kind of transformer isolation stillness wattless occurrence apparatus according to claim 1 and 2, it is characterized in that: described transformer isolation stillness wattless occurrence apparatus comprises control device, control device comprises signal acquisition module, idle computing module, idle distribution module, two closed-loop control modules and modulation module, signal acquisition module is gathered high side voltage and current signal by grid side voltage transformer and grid side current transformer, idle computing module is according to the voltage and current signal that collects, calculate the reactive current that SVG should compensate in real time, give each converter cell by idle distribution module by two closed-loop control modules and modulation module mean allocation again.
4. a kind of transformer isolation stillness wattless occurrence apparatus according to claim 3, it is characterized in that: described control module includes power control system link, idle controlling unit and dq transform part, meritorious controlling unit is two close-loop feedback control links, comprise ring and Voltage Feedback outer shroud in the current feedback, dc voltage u DcFeed back to control module and constitute Voltage Feedback outer shroud, active current i dFeedback adds pi regulator and constitutes ring in the current feedback; Idle controlling unit is current closed-loop control, distributes to the idle amount Q of converter cell 1Through proportional component K, produce reactive component of current reference signal i Qr, feedback signal is converter cell reactive component of current i qFeedback signal is through regulating through the PI controlling unit after relatively with reference signal, and the signal after the correction is changed to three-phase signal through the contravariant of dq transform part, and then relatively modulates by modulation module with the phase shift triangular wave, export to converter module at last, make converter module output three-phase current.
5. a kind of transformer isolation stillness wattless occurrence apparatus according to claim 4 is characterized in that: the tuple of described converter cell is a quadruple, and described semiconductor variable parallel operation comprises four half-bridge circuits in parallel.
6. a kind of transformer isolation stillness wattless occurrence apparatus according to claim 5 is characterized in that: described modulation module adopts the CPS-SPWM modulating mode, the CPS-SPWM signal of the every heavy converter cell 90 ° of phase places that stagger successively.
7. according to claim 4 or 5 described a kind of transformer isolation stillness wattless occurrence apparatus, it is characterized in that: the described shared control device of double converter cell that is no less than.
CN2011200777233U 2011-03-22 2011-03-22 Isolated static var generator of transformer Expired - Lifetime CN201937279U (en)

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Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN102130461A (en) * 2011-03-22 2011-07-20 株洲变流技术国家工程研究中心有限公司 Transformer-isolated static Var generator and control method thereof
CN102820660A (en) * 2012-08-17 2012-12-12 保定市尤耐特电气有限公司 Static var compensation system applicable to compensation of photovoltaic power station
CN104319770A (en) * 2014-11-12 2015-01-28 江苏东源电器集团股份有限公司 Intelligent active filter
CN105226656A (en) * 2015-10-22 2016-01-06 苏州华安普电力科技股份有限公司 A kind of multiple-harmonic-source harmonic shielding system
CN110994705A (en) * 2019-11-22 2020-04-10 广西交通职业技术学院 Common direct current bus bidirectional converter with power quality control function and control method thereof
CN113690899A (en) * 2021-07-13 2021-11-23 科华数据股份有限公司 APF parallel topology control method and device and APF system

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN102130461A (en) * 2011-03-22 2011-07-20 株洲变流技术国家工程研究中心有限公司 Transformer-isolated static Var generator and control method thereof
CN102820660A (en) * 2012-08-17 2012-12-12 保定市尤耐特电气有限公司 Static var compensation system applicable to compensation of photovoltaic power station
CN104319770A (en) * 2014-11-12 2015-01-28 江苏东源电器集团股份有限公司 Intelligent active filter
CN105226656A (en) * 2015-10-22 2016-01-06 苏州华安普电力科技股份有限公司 A kind of multiple-harmonic-source harmonic shielding system
CN110994705A (en) * 2019-11-22 2020-04-10 广西交通职业技术学院 Common direct current bus bidirectional converter with power quality control function and control method thereof
CN110994705B (en) * 2019-11-22 2023-07-21 广西交通职业技术学院 Common direct current bus bidirectional converter with electric energy quality control function and control method thereof
CN113690899A (en) * 2021-07-13 2021-11-23 科华数据股份有限公司 APF parallel topology control method and device and APF system
CN113690899B (en) * 2021-07-13 2023-04-07 科华数据股份有限公司 APF parallel topology control method and device and APF system

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