CN106300395A - Given feedforward control method for dynamically restraining subsynchronous oscillation of power grid based on SVG - Google Patents

Abstract

The invention provides a given feedforward control method for dynamically restraining subsynchronous oscillation of a power grid based on SVG (scalable vector graphics), which comprises the following steps: collecting three-phase current of a power grid; converting the real current into an active current actual value and a reactive current actual value; filtering the active current actual value and the reactive current actual value respectively, and then obtaining an active current component and a reactive current component for inhibiting the sub-synchronous oscillation of the power grid by taking the negative values; adding an active current given value into an active current component for inhibiting the subsynchronous oscillation of the power grid to obtain a total active current given value, and adding a reactive current given value into a reactive current component for inhibiting the subsynchronous oscillation of the power grid to obtain a total reactive current given value; and respectively carrying out closed-loop control on the total active current given value and the total reactive current given value to obtain compensation current for inhibiting subsynchronous oscillation of the power grid, so that the subsynchronous oscillation of the power grid is inhibited. The control method can dynamically and effectively inhibit the subsynchronous oscillation of the power grid.

Description

The given feed forward control method of electrical network sub-synchronous oscillation is dynamically suppressed based on SVG

Technical field

The present invention relates to power network reactive power compensation technical field, be specifically related to a kind of based on The dynamically suppression electrical network of SVG (Static Var Generator, static reacance generator) The given feed forward control method of synchronized oscillation.

Background technology

China is vast in territory, the energy and expanding economy geographically in contrary distribution, pole Imbalance, thus it is imperative to carry out Large Copacity, at a distance transmission of electricity.But, high pressure, The problem that remote conveying power technology exists power limited.

In prior art, general use fixing series compensation technology of transmission of electricity solve high pressure, Remote conveying power technology exist power limited problem, thus realize electric power netting safe running and Economic electric transmission, solves China's electric power and sends limitation problem.But, fixing series compensation is defeated Power technology, while improving transmission line of electricity conveying capacity, also gives some wind power plant bands The problem carrying out sub-synchronous oscillation (SSO, SubsynchronousOscillation), and secondary same Step vibration will have a strong impact on the stable operation of wind generator system.

For solving the sub-synchronous oscillation problem of electrical network, currently mainly use following several suppression The method of electrical network sub-synchronous oscillation: supplementary excitation damping control suppression method, block filter Suppression method, subsynchronous additional longitudinal forces suppression method, and SVC suppression Method.But, above-mentioned suppressing method is all provided without full-control type power device, thus to transmission of electricity The inhibition of the sub-synchronous oscillation in system is very limited.

Summary of the invention

The technical problem to be solved be for prior art in the presence of above-mentioned Defect, it is provided that a kind of based on SVG dynamic, effectively suppress the subsynchronous of electrical network to shake The given feed forward control method swung.

Solve the technology of the present invention problem be the technical scheme is that

The present invention provides a kind of and dynamically suppresses the given of electrical network sub-synchronous oscillation based on SVG Feed forward control method, described control method comprises the steps:

1) electrical network three-phase current is gathered；

2) described electrical network three-phase current is transformed into watt current actual value and reactive current is real Actual value；

3) respectively described watt current actual value and reactive current actual value are filtered place Reason, then negates the active current of the electrical network sub-synchronous oscillation that is inhibited and idle electricity Flow component；

4) in the active current of described suppression electrical network sub-synchronous oscillation, meritorious electricity is added Stream set-point is to obtain total watt current set-point and same at described suppression electrical network time The reactive current component of step vibration adds reactive current set-point, to obtain total idle electricity Stream set-point；

5) respectively described total watt current set-point and described total reactive current set-point are entered Row closed loop control, with the compensation electric current of the electrical network sub-synchronous oscillation that is inhibited, thus suppresses The sub-synchronous oscillation of electrical network.

Preferably, in described step 1) in, use current sensor built-in for SVG real The collection of existing electrical network three-phase current.

Preferably, described step 2) particularly as follows:

The described electrical network three-phase current under three-phase static coordinate system is made to be become by abc/dq coordinate Change, obtain the described watt current actual value under biphase rotating coordinate system and reactive current is real Actual value.

Preferably, in described step 3) in, use modal filter to have described respectively Merit current actual value and reactive current actual value are filtered processing, described modal filter Including the low pass filter being sequentially connected with, high pass filter and band filter, or bag Include high pass filter, low pass filter and the band filter being sequentially connected with.

Preferably, in described step 3) in, described band filter is with its input signal Sub-synchronous oscillation frequency centered by frequency.

Preferably, in described step 3) in, having of described suppression electrical network sub-synchronous oscillation The frequency range of merit current component and reactive current component is 2～50Hz.

Preferably, described step 5) particularly as follows:

51) described total watt current set-point and described watt current actual value are done difference, Form corresponding deviation value, this deviation value is carried out proportional plus integral control, to obtain and institute State the controlled quentity controlled variable that total watt current set-point is corresponding, and,

Described total reactive current set-point and described reactive current actual value are done difference, is formed Corresponding deviation value, carries out proportional plus integral control to this deviation value, with obtain with described always The controlled quentity controlled variable that reactive current set-point is corresponding；

52) by the controlled quentity controlled variable corresponding with described total watt current set-point and with described total nothing Controlled quentity controlled variable corresponding to merit given value of current value is transformed into the controlled quentity controlled variable of suppression electrical network sub-synchronous oscillation；

53) controlled quentity controlled variable of described suppression electrical network sub-synchronous oscillation is carried out pulse width modulation, Drive signal accordingly to generate, and the turned off power electronic devices in SVG is carried out Control, to produce the compensation electric current of suppression electrical network sub-synchronous oscillation, thus suppress electrical network Sub-synchronous oscillation.

Preferably, described step 52) particularly as follows:

Make the control corresponding with described total watt current set-point under biphase rotating coordinate system Amount and the controlled quentity controlled variable corresponding with described total reactive current set-point pass through dq/abc coordinate transform, Obtain the controlled quentity controlled variable of described suppression electrical network sub-synchronous oscillation under three-phase static coordinate system.

Preferably, described control method uses DSP to realize.

Beneficial effect:

The given feed forward control method of dynamic suppression electrical network sub-synchronous oscillation of the present invention exists Existing SVG dicyclo (current inner loop+DC voltage outer shroud/reactive power outer shroud) decoupling PI The electric current loop of control strategy adds and gives feedforward equivalent damping control strategy, specifically, Active current i at suppression electrical network sub-synchronous oscillation_{d_ref}Middle addition is gained merit given value of current Value I_{d_ref}(belonging to the known parameters in existing SVG dicyclo decoupling PI control strategy), To obtain total watt current set-point, and the idle electricity at suppression electrical network sub-synchronous oscillation Flow component i_{q_ref}Middle addition reactive current set-point I_{q_ref}(belong to the decoupling of existing SVG dicyclo Known parameters in PI control strategy), to obtain total reactive current set-point, the most right Total watt current set-point and total reactive current set-point carry out closed loop control, to be pressed down The compensation electric current of electrical network sub-synchronous oscillation processed, thus on the basis of existing SVG control strategy On effectively compensate for the sub-synchronous oscillation in (suppression) electrical network.Visible, the present invention exists Add on the basis of existing SVG dicyclo decoupling PI control strategy and dynamically suppress electricity online The control algolithm of net sub-synchronous oscillation, and existing SVG employing full-control type power device, because of And effectively can provide positive damping for wind power plant, effectively improve wind-power electricity generation system The stability of system.

Additionally, the present invention has simply, is easily achieved, the advantage of low cost, compared to The control strategy of other suppression electrical network sub-synchronous oscillation existing, can make SVG according in real time The compensation electric current of suppression electrical network sub-synchronous oscillation export more accurate wattful power rapidly Rate and reactive power, it is thus possible to the sub-synchronous oscillation problem effectively solved in electrical network.

Accompanying drawing explanation

Fig. 1 is that electrical network is subsynchronous shakes in dynamically suppression based on SVG described in the embodiment of the present invention The flow chart of the given feed forward control method swung；

Fig. 2 is a kind of structural representation of modal filter described in the embodiment of the present invention；

Fig. 3 is the another kind of structural representation of modal filter described in the embodiment of the present invention；

Fig. 4 is the sub-process figure of step S500 in Fig. 1；

Fig. 5 is that electrical network is subsynchronous shakes in dynamically suppression based on SVG described in the embodiment of the present invention The application schematic diagram of the given feed forward control method swung；

Fig. 6 a is for applying control method of the present invention and not applying controlling party of the present invention The oscillogram of the active power of the SVG output of method；

Fig. 6 b is for applying control method of the present invention and not applying control of the present invention The oscillogram of the reactive power of the SVG output of method；

Fig. 7 is for applying control method of the present invention and not applying controlling party of the present invention The oscillogram of the motor torque of the SVG of method.

Detailed description of the invention

For making those skilled in the art be more fully understood that technical scheme, knot below Close drawings and Examples the present invention is described in further detail.

In recent years, flexible AC transmitting system (FACTS, Flexible Alternative Current Transmission Systems) obtain relatively broad application and development.Base In the SVG of full-control type power device (IGBT) with its control performance and quickly flexibly Dynamic characteristic, receives the favor of user, thus is widely used in flexible AC transmission System.SVG (Static Var Generator, static reacance generator) is a kind of in parallel , the full-control type that reactive-load compensation can be carried out exchange power transmission and distribution device, can be in capacitive and perception In the range of be adjusted, fast response time, the present invention apply its suppression electrical network subsynchronous Vibration has more preferable damping, thus provides positive damping for wind power plant, effectively Improve the stability of wind generator system.The control strategy that the present invention uses includes: Active current and the filtering sieve of reactive current component to suppression electrical network sub-synchronous oscillation Choosing, the design of modal filter realizes, the design of given feedforward equivalent damping control strategy, And based on SVG suppression electrical network sub-synchronous oscillation whole control scheme, below by tool Body embodiment describes the present invention.

Embodiment:

As it is shown in figure 1, the present embodiment provides a kind of based on SVG dynamically suppresses online electricity The given feed forward control method of net sub-synchronous oscillation, it comprises the steps:

S100. electrical network three-phase current i is gathered_a,i_b,i_c。

Preferably, current sensor built-in for SVG is used to realize electrical network three-phase current i_a,i_b, i_cCollection.

S200. by electrical network three-phase current i_a,i_b,i_cIt is transformed into watt current actual value i_dAnd nothing Merit current actual value i_q。

Preferably, step S200 is particularly as follows: electrical network three-phase under making three-phase static coordinate system Electric current i_a,i_b,i_cBy abc/dq coordinate transform, obtain gaining merit under biphase rotating coordinate system Current actual value i_dWith reactive current actual value i_q。

Specifically, to electrical network three-phase current i_a,i_b,i_cCarry out three-phase-biphase (3s/2r) coordinate Conversion, i.e. becomes between three-phase static coordinate system abc and biphase rotating coordinate system dq Change, thus obtain watt current actual value i_dWith reactive current actual value i_q.Three-phase-biphase The formula that coordinate transform is used is as follows:

$\left[\begin{array}{c}{i}_d\\ i_q\end{array}\right]=\frac{2}{3}\left[\begin{array}{ccc}\sin \mathrm{\α}& \sin (\mathrm{\α}-\frac{2}{3}\mathrm{\π})& \sin (\mathrm{\α}+\frac{2}{3}\mathrm{\π})\\ \cos \mathrm{\α}& \cos (\mathrm{\α}-\frac{2}{3}\mathrm{\π})& \cos (\mathrm{\α}+\frac{2}{3}\mathrm{\π})\end{array}\right]\left[\begin{array}{c}{i}_a\\ i_b\\ i_c\end{array}\right]$

Parameter alpha in above formula is d axle and a axle clamp angle.

The most respectively to watt current actual value i_dWith reactive current actual value i_qFilter Ripple processes, and then negates the active current i of the electrical network sub-synchronous oscillation that is inhibited_{d_ref} With reactive current component i_{q_ref}, the composition of the electrical network sub-synchronous oscillation that is i.e. inhibited.Preferably Ground, the active current i of suppression electrical network sub-synchronous oscillation_{d_ref}With reactive current component i_{q_ref} Including frequency and amplitude, and frequency range is 2～50Hz.

In step S300, use modal filter respectively to watt current actual value i_d With reactive current actual value i_qBeing filtered processing, modal filter includes being sequentially connected with Low pass filter, high pass filter and band filter (as shown in Figure 2), or bag Include high pass filter, low pass filter and the band filter being sequentially connected with (such as Fig. 3 institute Show).Preferably, during band filter with the sub-synchronous oscillation frequency of its input signal is Frequency of heart.

Preferably, in modal filter, the cut-off frequency of low pass filter is logical higher than band The upper cut-off frequency of wave filter, the cut-off frequency of high pass filter is less than band filter Lower-cut-off frequency so that low pass filter and high pass filter have first filtered major part Useless signal, then the narrow-band filtering through band filter, filter out suppression effectively The composition of electrical network sub-synchronous oscillation, i.e. filters out the meritorious electricity of suppression electrical network sub-synchronous oscillation Flow component/reactive current component.

As a example by sub-synchronous oscillation frequency values is as 24Hz, select the cutoff frequency of low pass filter Rate is 40Hz, and the cut-off frequency of high pass filter is 10Hz, the center frequency of band filter Rate is 24Hz, then the transmission function G of low pass filter₁, the transmission function of high pass filter G₂Transmission function G with band filter₃As follows:

$G_1=\frac{63165.44}{s^2+251.2s+63165.44}$

$G_2=\frac{s^2}{s^2+62.8s+3947.84}$

$G_3=\frac{150.7s}{s^2+150.7s+22710.49}$

S400. at the active current i of suppression electrical network sub-synchronous oscillation_{d_ref}In there was added Merit given value of current value I_{d_ref}, to obtain total watt current set-point, and at suppression electrical network The reactive current component i of sub-synchronous oscillation_{q_ref}Middle addition reactive current set-point I_{q_ref}, with Obtain total reactive current set-point.Wherein, watt current set-point I_{d_ref}And reactive current Set-point I_{q_ref}All belong to the known parameters in existing SVG dicyclo decoupling PI control strategy, Here is omitted.

The most total watt current set-point and total reactive current set-point are closed Ring controls, and with the compensation electric current of the electrical network sub-synchronous oscillation that is inhibited, thus suppresses electrical network Sub-synchronous oscillation.

It can be seen that step S400 and S500 are by decoupling at existing SVG dicyclo The electric current loop of PI control strategy adds given feedforward equivalent damping control strategy (i.e. add The composition of suppression electrical network sub-synchronous oscillation) realize, suppression electrical network sub-synchronous oscillation Active current i_{d_ref}Reactive current component i with suppression electrical network sub-synchronous oscillation_{q_ref}All Belong to the composition of suppression electrical network sub-synchronous oscillation.

Preferably, as shown in Figure 4, step S500 comprises the steps:

S501. to total watt current set-point and watt current actual value i_dDo difference, formed Corresponding deviation value, carries out proportional integral (PI) and controls this deviation value, with obtain with The controlled quentity controlled variable that total watt current set-point is corresponding, and,

To total reactive current set-point and reactive current actual value i_qDo difference, form correspondence Deviation value, carries out proportional integral (PI) and controls, to obtain with the most idle this deviation value The controlled quentity controlled variable that given value of current value is corresponding.

S502. by the controlled quentity controlled variable corresponding with total watt current set-point and with total reactive current The controlled quentity controlled variable that set-point is corresponding is transformed into the controlled quentity controlled variable of suppression electrical network sub-synchronous oscillation.

Preferably, make under biphase rotating coordinate system is corresponding with total watt current set-point Controlled quentity controlled variable and the controlled quentity controlled variable corresponding with total reactive current set-point pass through dq/abc coordinate transform, Obtain the controlled quentity controlled variable suppressing electrical network sub-synchronous oscillation under three-phase static coordinate system.

Specifically, to controlled quentity controlled variable k corresponding with total watt current set-point_dAnd with the most idle Controlled quentity controlled variable k that given value of current value is corresponding_qCarry out biphase-three-phase (2r/3s) coordinate transform, i.e. Convert between biphase rotating coordinate system dq and three-phase static coordinate system abc, thus Be inhibited controlled quentity controlled variable k of electrical network sub-synchronous oscillation_a,k_b,k_c.Biphase-three-phase coordinate transform The formula used is as follows:

$\left[\begin{array}{c}{k}_a\\ k_b\\ k_c\end{array}\right]=\left[\begin{array}{cc}\sin \mathrm{\α}& \cos \mathrm{\α}\\ \sin (\mathrm{\α}-\frac{2}{3}\mathrm{\π})& \cos (\mathrm{\α}-\frac{2}{3}\mathrm{\π})\\ \sin (\mathrm{\α}+\frac{2}{3}\mathrm{\π})& \cos (\mathrm{\α}+\frac{2}{3}\mathrm{\π})\end{array}\right]\left[\begin{array}{c}{k}_d\\ k_q\end{array}\right]$

Parameter alpha in above formula is d axle and a axle clamp angle.

S503. the controlled quentity controlled variable of suppression electrical network sub-synchronous oscillation is carried out pulse width modulation (PWM), signal is driven accordingly to generate, and to the turned off electric power in SVG Electronic device (full-controlled switch pipe, such as IGBT) is controlled, and i.e. controls corresponding Full-controlled switch pipe action, to produce the compensation electric current of suppression electrical network sub-synchronous oscillation, from And suppress the sub-synchronous oscillation of electrical network.

In actual applications, step S100 moves in circles to step S500, changes speech It, often collect one group of electrical network three-phase current i_a,i_b,i_c, just according to step S200 to step It is processed by the method described in S500, and to produce, corresponding suppression electrical network is subsynchronous to shake The compensation electric current swung, makes SVG according to the compensation electricity of real-time suppression electrical network sub-synchronous oscillation Stream exports accurate active power and reactive power such that it is able to dynamically, effectively suppress The sub-synchronous oscillation of electrical network.

In the present embodiment, described control method can use digital signal processor (DSP, Digital Signal Processing) realize, its have online, carry out digital operation in real time Advantage.When the collection using current sensor built-in for SVG to realize electrical network three-phase current Time, owing to the signal of current sensor output cannot directly be identified by DSP, therefore described Control method also needs to first the signal that current sensor exports is converted into DSP readable Step S200 is carried out again after signal.

Based on SVG dynamically the pressing down using DSP realization is described in detail below in conjunction with Fig. 5 The given feed forward control method of electrical network sub-synchronous oscillation processed.In Fig. 5, PI represents that ratio is amassed Sub-controller (i.e. PI controller), PWM represents Pulse width modulation module (i.e. PWM Module).

Use current sensor Real-time Collection electrical network three-phase current i built-in for SVG_a,i_b,i_c； Make the electrical network three-phase current i under three-phase static coordinate system_a,i_b,i_cBy abc/dq coordinate transform, Obtain the watt current actual value i under biphase rotating coordinate system_dWith reactive current actual value i_q, Export the most respectively to modal filter, by the low pass filter in modal filter, height Bandpass filter and band filter are to watt current actual value i_d/ reactive current actual value i_qDepend on Secondary low-pass filtering, high-pass filtering and the bandpass filtering treatment of carrying out, then negates and is inhibited The active current i of electrical network sub-synchronous oscillation_{d_ref}/ reactive current component i_{q_ref}；In suppression The active current i of electrical network sub-synchronous oscillation_{d_ref}Middle addition is gained merit given value of current value I_{d_ref}, Obtain total watt current set-point, and the reactive current at suppression electrical network sub-synchronous oscillation Component i_{q_ref}Middle addition reactive current set-point I_{q_ref}, obtain total reactive current set-point； Respectively total watt current set-point and total reactive current set-point are carried out closed loop control, i.e. Total watt current set-point and watt current actual value are done difference, form corresponding deviation value, Make this deviation value by PI controller, obtain the control corresponding with total watt current set-point Amount, and, total reactive current set-point and reactive current actual value are done difference, it is right to be formed The deviation value answered, makes this deviation value by PI controller, obtains giving with total reactive current The controlled quentity controlled variable that value is corresponding；Make under biphase rotating coordinate system with total watt current set-point pair The controlled quentity controlled variable answered and the controlled quentity controlled variable corresponding with total reactive current set-point are by dq/abc coordinate Conversion, obtains the controlled quentity controlled variable suppressing electrical network sub-synchronous oscillation under three-phase static coordinate system； The controlled quentity controlled variable making suppression electrical network sub-synchronous oscillation passes through PWM module, i.e. to suppression electrical network The controlled quentity controlled variable of sub-synchronous oscillation carries out pulse width modulation, drives signal accordingly to generate, And the turned off power electronic devices in SVG is controlled, to produce suppression electrical network The compensation electric current of synchronized oscillation, thus suppress the sub-synchronous oscillation of electrical network.Need explanation It is, by the DC voltage set-point u of original for SVG DC voltage outer shroud_{dc_ref}With direct current Voltage actual value u_dcDo difference, form meritorious power offset value Δ P, this active power deviation value Δ P obtains watt current set-point I after PI controller carries out proportional plus integral control_{d_ref}； By the reactive power set-point Q of original for SVG reactive power outer shroud_{m_ref}With reactive power Actual value Q_mDo difference, form inclined difference DELTA Q of reactive power, inclined difference DELTA Q of this reactive power Reactive current set-point I is obtained after PI controller carries out proportional plus integral control_{q_ref}.Wherein, The DC voltage set-point u of DC voltage outer shroud_{dc_ref}, DC voltage actual value u_dc, idle The reactive power set-point Q of power outer shroud_{m_ref}With reactive power actual value Q_mIt is existing Known parameters in SVG dicyclo decoupling PI control strategy.

The present invention has also carried out simulating, verifying to described control method, simulation result such as Fig. 6 a, Shown in Fig. 6 b and Fig. 7, Fig. 6 a is for applying control method of the present invention and not applying this Inventing the oscillogram of the active power of the SVG output of described control method, Fig. 6 b is for answering By control method of the present invention with do not apply the SVG of control method of the present invention to export The oscillogram of reactive power, Fig. 7 is for applying control method of the present invention and not applying The oscillogram of the motor torque of the SVG of control method of the present invention, and in analogous diagram Solid line is the simulation waveform applying control method of the present invention to obtain, and dotted line is existing The simulation waveform of technology, it can be seen that control method of the present invention restrained effectively The ripple of the output torque of active power fluctuation, reactive power fluctuation and the electrode of SVG output Dynamic, thus demonstrate the accuracy of control method of the present invention, simplification and reliability, Good reference value is provided for engineer applied.

It is understood that the principle that embodiment of above is intended to be merely illustrative of the present And the illustrative embodiments used, but the invention is not limited in this.For ability For those of ordinary skill in territory, in the situation without departing from spirit and substance of the present invention Under, various modification and improvement can be made, these modification and improvement are also considered as the present invention's Protection domain.

Claims (9)

1. the given feedforward dynamically suppressing electrical network sub-synchronous oscillation based on SVG Method, it is characterised in that described control method comprises the steps:

1) electrical network three-phase current is gathered；

2) described electrical network three-phase current is transformed into watt current actual value and reactive current is real Actual value；

3) respectively described watt current actual value and reactive current actual value are filtered place Reason, then negates the active current of the electrical network sub-synchronous oscillation that is inhibited and idle electricity Flow component；

4) in the active current of described suppression electrical network sub-synchronous oscillation, meritorious electricity is added Stream set-point is to obtain total watt current set-point and same at described suppression electrical network time The reactive current component of step vibration adds reactive current set-point, to obtain total idle electricity Stream set-point；

5) respectively described total watt current set-point and described total reactive current set-point are entered Row closed loop control, with the compensation electric current of the electrical network sub-synchronous oscillation that is inhibited, thus suppresses The sub-synchronous oscillation of electrical network.

Control method the most according to claim 1, it is characterised in that in described step Rapid 1), in, current sensor built-in for SVG is used to realize the collection of electrical network three-phase current.

Control method the most according to claim 1, it is characterised in that described step 2) particularly as follows:

The described electrical network three-phase current under three-phase static coordinate system is made to be become by abc/dq coordinate Change, obtain the described watt current actual value under biphase rotating coordinate system and reactive current is real Actual value.

Control method the most according to claim 1, it is characterised in that in described step Rapid 3), in, use modal filter respectively to described watt current actual value and reactive current Actual value is filtered processing, and described modal filter includes the low-pass filtering being sequentially connected with Device, high pass filter and band filter, or include being sequentially connected with high pass filter, Low pass filter and band filter.

Control method the most according to claim 4, it is characterised in that in described step Rapid 3), in, described band filter is centered by the sub-synchronous oscillation frequency of its input signal Frequency.

Control method the most according to claim 1, it is characterised in that in described step Rapid 3), in, active current and the reactive current of described suppression electrical network sub-synchronous oscillation are divided The frequency range of amount is 2～50Hz.

Control method the most according to claim 1, it is characterised in that described step 5) particularly as follows:

51) described total watt current set-point and described watt current actual value are done difference, Form corresponding deviation value, this deviation value is carried out proportional plus integral control, to obtain and institute State the controlled quentity controlled variable that total watt current set-point is corresponding, and,

Described total reactive current set-point and described reactive current actual value are done difference, is formed Corresponding deviation value, carries out proportional plus integral control to this deviation value, with obtain with described always The controlled quentity controlled variable that reactive current set-point is corresponding；

52) by the controlled quentity controlled variable corresponding with described total watt current set-point and with described total nothing Controlled quentity controlled variable corresponding to merit given value of current value is transformed into the controlled quentity controlled variable of suppression electrical network sub-synchronous oscillation；

53) controlled quentity controlled variable of described suppression electrical network sub-synchronous oscillation is carried out pulse width modulation, Drive signal accordingly to generate, and the turned off power electronic devices in SVG is carried out Control, to produce the compensation electric current of suppression electrical network sub-synchronous oscillation, thus suppress electrical network Sub-synchronous oscillation.

Control method the most according to claim 7, it is characterised in that described step 52) particularly as follows:

Make the control corresponding with described total watt current set-point under biphase rotating coordinate system Amount and the controlled quentity controlled variable corresponding with described total reactive current set-point pass through dq/abc coordinate transform, Obtain the controlled quentity controlled variable of described suppression electrical network sub-synchronous oscillation under three-phase static coordinate system.

9. according to the control method according to any one of claim 1～8, it is characterised in that Described control method uses DSP to realize.