CN101572415B - Method for controlling series voltage quality compensator - Google Patents
Method for controlling series voltage quality compensator Download PDFInfo
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- CN101572415B CN101572415B CN2009100215267A CN200910021526A CN101572415B CN 101572415 B CN101572415 B CN 101572415B CN 2009100215267 A CN2009100215267 A CN 2009100215267A CN 200910021526 A CN200910021526 A CN 200910021526A CN 101572415 B CN101572415 B CN 101572415B
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Abstract
The invention relates to the field of power network power quality optimization, and discloses a method for controlling a series voltage quality compensator. The method comprises the following steps: detecting three-phase voltage uS of a power supply, and acquiring three-phase phase omegat of supply voltage through a three-way phase-locked loop respectively; detecting voltage udc at an SVQC directcurrent side, comparing the udc with a set voltage value udc* of the direct current side through a one-way subtracter, regulating the output through a one-way proportional integral regulator, and using the output of a one-way proportional integrator as a compensation phase shifting angle delta; summarizing the three-phase phase omegat of the supply voltage with the compensation phase shifting angle delta through a three-way summator respectively, and using the result as a three-phase phase reference value alpha of load voltage; setting an amplitude reference value A of the load voltage, inputting the amplitude reference value A of the load voltage and the three-phase phase reference value alpha of the load voltage into a three-way sine-wave generator, and using the output as a load three-phase voltage reference value uL*; and detecting the actual three-phase voltage uL of the load, forming a voltage control closed loop, and tracking load three-phase voltage reference value uL*.
Description
Technical field
The present invention relates to electrical network electric energy quality optimizing field, particularly a kind of control method of series voltage quality compensator.
Background technology
In recent years, along with the continuous technology innovation of progress of science and technology, power consumption equipment, many automations, digitized sensitive loads have obtained using widely.These equipment are also had higher requirement to the quality of voltage of electric power system when promoting that actively production efficiency improves.Series voltage quality compensator (Series Voltage Quality Compensator is called for short SVQC) is a development in recent years class compensation arrangement rapidly, can effectively solve most of grid side quality of voltage problem.
In the system configuration of series voltage quality compensator, main circuit is made of DC side energy storage device, voltage-source type pwm converter, output filter and coupling transformer.SVQC can produce the voltage of certain frequency, amplitude and phase place as required, and when line voltage fell temporarily, it can provide certain voltage, and the proof load voltage amplitude is constant.
The control method of series voltage quality compensator has determined its compensation performance, all is the emphasis that people pay close attention to all the time.The major control target of SVQC is when line voltage has disturbance, and the proof load voltage amplitude is constant.Therefore, its control method can be divided into two parts: the generation of load voltage desired value and the tracking Control of load voltage.The desired value amplitude of load voltage is fixed, but under a lot of application scenarios, phase place is a free amount that can change.Phase shifting angle will influence the compensation performance of SVQC to a great extent, and therefore, Many researchers is at how selecting suitable phase shifting angle to launch research.In early days, people are most to use phase places before the electric network fault, like this can proof load voltage before and after fault amplitude and phase place all constant substantially.Active power big, output is more but this method often causes the voltage amplitude of SVQC output, therefore, is not a kind of selection of economy.Therefore, there is the researcher to propose same-phase control, makes the line voltage same-phase after load voltage and the fault, can guarantee the output voltage amplitude minimum of SVQC like this.But the weak point of same-phase control is: fall temporarily as long as line voltage takes place, SVQC just must provide active power, causes system must dispose bigger DC side energy storage device, has increased cost.And when the line voltage appearance was temporarily high, the same-phase control method made SVQC absorb active power, and this part active power causes the SVQC running efficiency of system to descend often by loss in vain.Afterwards, (Feb.2000 pp.51-57) has proposed the energy-optimised control of SVQC to document " Dynamic voltage restoration with minimum energy injection " for IEEETransactions on Power Systems, Vol.15.Energy-optimised control method is a target with the active power of output that minimizes SVQC.This control method calculates the phase shifting angle of SVQC optimum according to the degree of electric network electric voltage drop and the impedance angle of load.When the electric network electric voltage drop degree not simultaneously, SVQC may work in different two states: zero meritorious injection state and minimum meritorious injection state.Compare with two kinds of methods before, energy-optimised control complexity rises greatly, needs complicated calculating and judgement, and needs to detect the impedance angle of load, has improved system cost.On this basis, document " Dc-link Voltage Pumping-up Analysisand Phase Shift Control for a Series Active Voltage Regulator " (PowerElectronics Specialists Conference.2006.PESC ' 06.37th IEEE, June 2006pp.1-5) has proposed the phase shifting angle generation method based on FEEDBACK CONTROL.This control method control system is simple in structure, does not need to detect load impedance angle, has reduced system cost, but but has potential instability problem.
Summary of the invention
The object of the present invention is to provide a kind of control method of series voltage quality compensator, this control method is under the prerequisite that does not increase system cost, SVQC is always worked under the energetic optimum, and can effectively avoid potential instability problem, guarantee the maximization of SVQC system balance time, compensation effect is good.
In order to achieve the above object, the present invention is achieved by the following technical solutions.A kind of control method of series voltage quality compensator is characterized in that, may further comprise the steps:
Further improvement of the present invention is:
Described compensation phase shifting angle δ through behind the dynamic amplitude limiter amplitude limit, imports three tunnel adders; The higher limit δ of described dynamic amplitude limiter
Up-limitWith lower limit δ
Lower-limitDetermine in the following manner: at first, gather the dc voltage u of SVQC
Dc, and ask for its first derivative
And second dervative
The second dervative of its current time
Second dervative with previous moment
During jack per line, higher limit δ
Up-limitWith lower limit δ
Lower-limitConstant; The second dervative of current time
Second dervative with previous moment
Contrary sign or wherein have one to be zero, and the first derivative of current time
Greater than 0 o'clock, the compensation phase shifting angle δ (N) of current time was as higher limit δ
Up-limitThe second dervative of current time
Second dervative with previous moment
Contrary sign or wherein have one to be zero, and the first derivative of current time
Smaller or equal to 0 o'clock, the compensation phase shifting angle δ (N) of current time was as lower limit δ
Lower-limit
The realization of the present invention in control is simply easy, the detection of having saved the power-factor of load, and can make the SVQC system always work in the energetic optimum compensating coefficient, and effectively utilized the DC side energy storage device, reduced system cost.Meanwhile, the control of keeping the load voltage amplitude is constant, does not influence whole system compensation target, can keep the load voltage amplitude constant, functional when line voltage suddenlys change.
Description of drawings
Fig. 1 is the series voltage quality compensator main circuit structure;
Fig. 2 is the control block diagram among the present invention;
Fig. 3 is control device system diagram among the present invention;
Fig. 4 is the higher limit of the amplitude limiter among the present invention and the self adaptation correction FB(flow block) of lower limit;
The active power that Fig. 5 absorbs or discharges for phase shifting angle δ and the SVQC of SVQC concern schematic diagram.
Embodiment
With reference to Fig. 1, connect series voltage quality compensator 2 between three phase mains 1 and the nonlinear load 3.The main circuit structure of series voltage quality compensator 2 mainly comprises: DC side energy storage device 201, voltage-source type pwm converter 202, output filter 203 and coupling transformer 204 4 parts constitute.DC side energy storage device 202 generally is made of the power capacitor connection in series-parallel.Voltage-source type pwm converter 202 adopts full control device such as compositions such as IGBT, GTO.Output filter 203 employings are connected on the filter inductance of voltage-source type pwm converter 202 AC side and LC filter in parallel is realized; The selection of LC filter parameter depends primarily on the switching frequency of voltage-source type pwm converter, but LC filter additional damping resistance suppress to shake, its parameter request is compromised to select for use between filter effect and damping and is got final product.Coupling transformer 204 is connected between three phase mains 1 and the voltage-source type pwm converter 202, its effect mainly is that the bucking voltage that voltage-source type pwm converter 202 produces is coupled to the disturbance of three phase mains 1 with counteracting three phase mains 1, thereby keeps load voltage constant.
In order to narrate conveniently, among the present invention, the power supply three-phase voltage is designated as u
s, that is: u
Sa, u
Sb, u
ScThe three-phase phase ω t of supply voltage, that is: ω t
a, ω t
b, ω t
cThe power supply three-phase current is designated as i
s, that is: i
Sa, i
Sb, i
ScThe dc voltage of series voltage quality compensator (SVQC) is designated as u
Dc, the dc voltage set point is designated as u
Dc *The three-phase compensation voltages of series voltage quality compensator (SVQC) output is designated as u
c, that is: u
Ca, u
Cb, u
CcThreephase load voltage is designated as u
L, that is: u
La, u
Lb, u
LcLoad three-phase voltage reference value is designated as u
L *, i.e. u
La *, u
Lb *, u
Lc *
Load three-phase voltage amplitude reference value is designated as A; Load voltage three-phase phase reference value is designated as α; The compensation phase shifting angle of series voltage quality compensator is designated as δ.
With reference to Fig. 2, Fig. 3, the control method of the series voltage quality compensator among the present invention may further comprise the steps:
In the SVQC system, load three-phase voltage reference value u
L *With the actual three-phase voltage u of detected load
LCompare, the voltage-source type pwm converter output among the control SVQC realizes that the actual three-phase voltage of load is u
LControl; In above-mentioned voltage control closed loop, the control mode that relates to the voltage-source type pwm converter can adopt traditional control mode.
With reference to Fig. 4, the amplitude limit value dynamic change of amplitude limiter, its higher limit δ
Up-limitWith lower limit δ
Lower-limitDetermine in the following manner: at first, gather the dc voltage u of SVQC
Dc, and ask for its first derivative
And second dervative
The second dervative of its current time
Second dervative with previous moment
During jack per line, higher limit δ
Up-limitWith lower limit δ
Lower-limitConstant; The second dervative of current time
Second dervative with previous moment
Contrary sign or wherein have one to be zero, and the first derivative of current time
Greater than 0 o'clock, the compensation phase shifting angle δ (N) of current time was as higher limit δ
Up-limitThe second dervative of current time
Second dervative with previous moment
Contrary sign or wherein have one to be zero, and the first derivative of current time
Smaller or equal to 0 o'clock, the compensation phase shifting angle δ (N) of current time was as lower limit δ
Lower-limit
In the practice, lower limit δ
Lower-limitInitial value get 0, higher limit δ
Up-limitInitial value get 180 degree, purpose is before not calculating amplitude limit value, allows all signals all to pass through, and amplitude limit not.
With reference to Fig. 5, the relation between the active power that actual phase shifting angle δ and the SVQC of SVQC absorb or discharge is described.The active power P that sends when electrical network
SActive power P greater than the load absorption
LThe time, as δ among the figure
2To δ
4The interval, SVQC absorbs active power.The active power P that sends when electrical network
SActive power P less than the load absorption
LThe time, as δ among the figure
1To δ
2The interval, SVQC discharges active power.
Generally speaking, the phase shifting angle of SVQC is big more, and the active power that the DC side energy storage device is absorbed is big more, but along with after phase shifting angle increases to a certain degree, reduces instead the active power that the DC side energy storage device absorbed occurs, as δ among the figure thereupon
3To δ
4The interval, this just can cause system to enter labile state.
In the SVQC system, the variation of phase shifting angle can be so that SVQC be in different operating states, and optimum situation is that when SVQC had to active power of output, the active power of output was the least possible, to obtain longer supporting time; And when SVQC need absorb active power, the active power of absorption was many as far as possible, to recover dc voltage as early as possible to set point.
Under the prerequisite of guaranteeing the load voltage amplitude,, when SVQC has to active power is provided, wish that the active power of output is the least possible when line voltage falls greatlyyer temporarily; When line voltage recovers, wish that SVQC recovers dc voltage as early as possible to set point, promptly the active power of Xi Shouing is many as far as possible.And the active power that SVQC absorbed and discharged is embodied directly on the rate of change (being the amplitude of the first derivative of dc voltage) of dc voltage.When the first derivative amplitude of dc voltage was in peak (paddy) value, the phase shifting angle of this moment was upward (descending) amplitude limit value of expectation.Therefore, ask for the second dervative of dc voltage earlier, when second dervative equalled zero, first derivative reached extreme value.Judge the positive and negative of first derivative afterwards again, the amplitude limit value that can obtain to expect.
Because there is non-linear relation in the active power that the phase shifting angle of SVQC and DC side energy storage device absorb, have potential instability problem, increase dynamic amplitude limiter, can effectively avoid potential instability problem in the control method of traditional series voltage quality compensator, and the control of the voltage close loop in the main three-phase voltage type pwm converter of the function of compensating load voltage is realized.The present invention is particularly suitable for the SVQC system that the DC side energy storage device is an electric capacity, and this electric capacity does not have other energy sources.
Claims (2)
1. the control method of a series voltage quality compensator is characterized in that, may further comprise the steps:
Step 1 detects power supply three-phase voltage u
s, obtain the three-phase phase ω t of supply voltage respectively by three road phase-locked loops;
Step 2 detects series voltage quality compensator SVQC dc voltage u
Dc, and with the dc voltage set point
Compare through the single channel subtracter, its output is adjusted through the single channel proportional and integral controller, and the output of single channel proportional and integral controller is phase shifting angle δ by way of compensation;
Step 3, with the three-phase phase ω t of supply voltage by three tunnel adders respectively with compensation phase shifting angle δ addition, its result is as the three-phase phase reference value alpha of load voltage;
Step 4 is set load voltage amplitude reference value A, and the three-phase phase reference value alpha of load voltage amplitude reference value A and load voltage is imported No. three sine-wave generators, and it is exported as load three-phase voltage reference value
Detect the actual three-phase voltage u of load
L, constitute the voltage control closed loop, follow the tracks of load three-phase voltage reference value
2. the control method of a kind of series voltage quality compensator according to claim 1 is characterized in that, described compensation phase shifting angle δ through behind the dynamic amplitude limiter amplitude limit, imports three tunnel adders; The higher limit δ of described dynamic amplitude limiter
Up-limitWith lower limit δ
Lower-limitDetermine in the following manner: at first, gather the dc voltage u of series voltage quality compensator SVQC
Dc, and ask for its first derivative
And second dervative
The second dervative of its current time
Second dervative with previous moment
During jack per line, higher limit δ
Up-limitWith lower limit δ
Lower-limitConstant; The second dervative of current time
Second dervative with previous moment
Contrary sign or wherein have one to be zero, and the first derivative of current time
Greater than 0 o'clock, the compensation phase shifting angle δ (N) of current time was as higher limit δ
Up-limitThe second dervative of current time
Second dervative with previous moment
Contrary sign or wherein have one to be zero, and the first derivative of current time
Smaller or equal to 0 o'clock, the compensation phase shifting angle δ (N) of current time was as lower limit δ
Lower-limit
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CN102158115B (en) * | 2011-04-06 | 2013-11-06 | 江苏禾力清能电气有限公司 | Controlling and optimizing method of grid-combining three-phase voltage source converter in accumulator storage system |
CN106547299B (en) * | 2016-10-09 | 2017-11-03 | 河北汉光重工有限责任公司 | A kind of high precision closed loop reference power source |
CN106961111A (en) * | 2017-04-28 | 2017-07-18 | 上海电力学院 | A kind of two-way dynamic voltage regulation device |
CN107689817B (en) * | 2017-09-30 | 2021-06-04 | 北京国电通网络技术有限公司 | Method and system for identifying phase of subscriber station area |
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CN1375904A (en) * | 2002-04-29 | 2002-10-23 | 清华大学 | Voltage compensating method of serially connected electrical energy quality compensator |
CN1862906A (en) * | 2006-06-01 | 2006-11-15 | 西安交通大学 | Series active AC voltage quality regulator and controlling method |
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CN1375904A (en) * | 2002-04-29 | 2002-10-23 | 清华大学 | Voltage compensating method of serially connected electrical energy quality compensator |
CN1862906A (en) * | 2006-06-01 | 2006-11-15 | 西安交通大学 | Series active AC voltage quality regulator and controlling method |
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