CN106229991A - A kind of Vienna Rectifier being applicable in the case of disturbance occurs in line voltage - Google Patents

Abstract

The present invention relates to a kind of Vienna Rectifier being applicable in the case of disturbance occurs in line voltage, for three-phase four-wire system Vienna commutator, disclose a kind of modified model electric current tracking based on Repetitive controller, mainly solve Traditional control not enough of both reply power quality problem and current tracking effect.This invention relates generally to the following aspects: (1) for electrical network background harmonics and periodically subsides, takes pll output signal as current tracking signal, mask voltage harmonic information；(2) introduce Repetitive controller in parallel with conventional PI control, appropriate design repetitive controller parameter, improve current tracking effect.Compared with prior art, the present invention is effectively improved current on line side quality, maintains DC-side Voltage Stabilization.

Description

A kind of line voltage that is applicable to occurs that the Vienna commutator in the case of disturbance controls Method

Technical field

The present invention relates to a kind of Vienna Rectifier, be applicable to line voltage particularly to one and harmonic wave occurs Or in the case of subsiding, it is effectively improved the control method of network side current waveform quality, belong to electrical network cutting-in control field.

Background technology

Electrical network generally exists the power quality problems such as voltage three-phase imbalance, voltage collapse, voltage harmonic, problems Directly affect the reliability service of power load.Direct current network and mixed DC electrical network are fast-developing, if in AC network at present There is harmonic wave, then can partly inject in direct-current micro-grid, harmonic current therein can cause the fluctuation of DC voltage, and then impact The power supply reliability of direct current network, direct current network also can react on AC network simultaneously, produces bigger harm.Therefore rectification Device is particularly important for the reply of power quality problem.

Traditional control method is based only on desired voltage condition, directly uses voltage sampling signal as reference, is easily subject to The impact of power network fluctuation, stability and reliability are the highest.Run in particular for electrical network background harmonics and power electronic devices The voltage collapse problem caused, traditional control method is processing power quality problem and is improving the reply of current tracking precision two aspect Not enough.

Summary of the invention

The present invention is applicable to line voltage and occurs that the Vienna Rectifier in the case of disturbance discloses new side Case, uses the fundametal compoment of phaselocked loop extraction voltage sampling signal as current tracking reference signal, solves existing controlling party The problem that case current tracking precision is not enough.

The present invention is applicable to the Vienna Rectifier in the case of disturbance occurs in line voltage, and control system includes Input voltage U_SSampling module, input inductive current i_LSampling module, output filter capacitor voltage U_CSampling module, PI controller, PWM module, input voltage U_SSampling module passes through abs rectifier bridge sampled input voltage U_SSignal and output filter capacitor voltage U_C Sampling module passes through PI_CSampled voltage ring output after controller process is multiplied and obtains electric current loop reference signal i_ref, electric current loop is joined Examine signal i_refWith input inductive current i_LThe current signal that sampling module sampling obtains subtracts each other and obtains current error signal i_err, electricity Stream error signal i_errBeing decreased to stable operating point after being processed by PI controller, signal processes rear drive by PWM module and switchs Device S action, uses phaselocked loop to extract the phase signal reference letter as current signal of input voltage Us signal fundamental component Number, the harmonic component in shielding sampled voltage so that current tracking sine is undistorted.

Further, this programme uses Repetitive controller module formation in parallel with PI controller complex controll electric current loop, at one After power frequency period, by mould in Repetitive controller, error is added up, improve electric current loop tracking effect, complex controll electric current loop bag Include cycle time delay process z^-N, auxiliary compensation device Q (z), controll plant compensator S (z), differentiation element z^k, proportional plus integral control ring Joint PI, is multiplied phaselocked loop signal with Voltage loop output and obtains reference signal i of electric current loop_ref, i_refWith current sampling signal phase Subtract and obtain current error signal i_err, load produces sudden change or disturbance, and actual current deviation reference value, PI controller adjusts electric current Deviation, all after date Repetitive controller detects tracking error i_err, in Repetitive controller mould current error is carried out Cycle by Cycle add up Until i_errConvergence 0, improves current waveform quality by the quickly response of PI controller with precisely following the tracks of of Repetitive controller module.

The present invention is applicable to line voltage and occurs that the Vienna Rectifier in the case of disturbance uses phaselocked loop to carry Take the fundametal compoment of voltage sampling signal as current tracking reference signal, the harmonic component in shielding sampled voltage so that electricity Stream is followed the tracks of sinusoidal undistorted, has the advantages that current tracking precision is high.

Accompanying drawing explanation

Fig. 1 is three-phase four-wire system Vienna rectifier topology structure schematic diagram.

Fig. 2 is voltage collapse fft analysis figure.

Fig. 3 is the single-phase Traditional control schematic diagram of three-phase four-wire system Vienna commutator.

Fig. 4 is the modified model current follow-up control schematic diagram based on Repetitive controller of this programme.

Fig. 5 is the complex controll electric current loop principle schematic of this programme.

Fig. 6 is function characteristic figure in complex controll.

Fig. 7,8 it is Traditional control current waveform figure in the case of harmonic wave.

Fig. 9,10 it is complex controll current waveform figure in the case of harmonic wave.

Figure 11 is DC voltage oscillogram under Traditional control.

Figure 12 is DC voltage oscillogram under complex controll.

Detailed description of the invention

Below in conjunction with accompanying drawing, the invention will be further described.

The present invention is applicable to line voltage and occurs that the Vienna Rectifier in the case of disturbance discloses a kind of base In the modified model electric current tracking of Repetitive controller, first Voltage Harmonic and the essence periodically subsided are carried out point Analysis, then proposes raising current tracking precision in the case of grid disturbances, improves the control of network side current waveform quality Process processed.Specifically include herein below.

(1) Voltage Harmonic is subsided with periodicity.By the waveform of voltage collapse is carried out Fourier analysis, can obtain To high frequency harmonic components therein, it can thus be assumed that it is identical with the impact that Vienna commutator is caused by harmonic problem, therefore return Solve for same problem.

As it is shown in figure 1, three-phase four-wire system Vienna rectifier topology structure schematic diagram.Wherein, the inductance L of AC plays Transmission energy, suppresses higher hamonic wave, balance brachium pontis terminal voltage and the effect of line voltage, output filter capacitor C₁、C₂For high order Harmonic current provides low impedance path, reduces DC voltage ripple, the effect of balance midpoint potential, and the every phase in three-phase is all by one Individual full control switching device S, four diode composition two-way switch.When electrical network accesses the rectified load being made up of thyristor bridge Time, line voltage can cut-off moment appearance periodically depression at IGCT, thus can simulate voltage collapse waveform.Such as Fig. 2 Shown in, to subsiding, waveform carries out fft analysis, it can be seen that it is in addition to fundametal compoment, possibly together with more higher harmonic components, Wherein based on 5,11,17 subharmonic.Therefore, during voltage collapse problem can also regard preferable fundamental frequency voltages as, it has been mixed into high order Harmonic wave.

(2) current tracking.Utilize phaselocked loop, extract the fundametal compoment of voltage sampling signal as current tracking reference signal. So can shield the harmonic component in sampled voltage so that current tracking sine is undistorted.

As it is shown on figure 3, the single-phase Traditional control schematic diagram of three-phase four-wire system Vienna commutator.Control system includes input Voltage U_SSampling module, input inductive current i_LSampling module, output filter capacitor voltage U_CSampling module, PI controller, PWM Module, input voltage U_SSampling module passes through abs rectifier bridge sampled input voltage U_SSignal and output filter capacitor voltage U_CSampling Module passes through PI_CSampled voltage ring output after controller process is multiplied and obtains electric current loop reference signal i_ref, electric current loop is with reference to letter Number i_refWith input inductive current i_LThe current signal that sampling module sampling obtains subtracts each other and obtains current error signal i_err, electric current is by mistake Difference signal i_errBeing decreased to stable operating point after being processed by PI controller, signal processes rear drive switching device by PWM module S action.As in figure 2 it is shown, use phaselocked loop to extract the phase signal of voltage signal Us fundamental component, as the reference of current signal Signal, when Us contains higher hamonic wave, its fundamental frequency signal is ideal sinusoidal signal.Ideally, power network current can be effective Follow the tracks of this signal, it is achieved sinusoidal undistorted.

(3) complex controll.Conventional PI control tracking accuracy is limited, introduces Repetitive controller and controls in parallel with PI, improves electric current loop Tracking effect, improves current waveform quality.

As shown in Figure 2,3, phaselocked loop signal is multiplied with Voltage loop output, obtains the reference signal of electric current loop, itself and electric current Sampled signal is subtracted each other, and obtains current error signal.This error signal controls to reduce, near stable operating point rapidly by PI. After one power frequency period, by mould in Repetitive controller, error is added up, it is achieved preferably control effect.Specifically, use Repetitive controller module formation in parallel with PI controller complex controll electric current loop, after a power frequency period, by Repetitive controller Error is added up by mould, improves electric current loop tracking effect, and complex controll electric current loop includes cycle time delay process z^-N, auxiliary compensation Device Q (z), controll plant compensator S (z), differentiation element z^k, proportional plus integral control link PI, by phaselocked loop signal and Voltage loop Output is multiplied and obtains reference signal i of electric current loop_ref, i_refSubtract each other with current sampling signal and obtain current error signal i_err, load Producing sudden change or disturbance, actual current deviation reference value, PI controller adjusts current deviation, all after date Repetitive controller detection To tracking error i_err, in Repetitive controller, that current error carries out Cycle by Cycle is cumulative until i for mould_errConvergence 0, by PI controller Quickly response improves current waveform quality with precisely following the tracks of of Repetitive controller module.

Setting up the mathematical model of Vienna commutator, according to volt-second characteristic, can obtain in the control cycle, inductive current moves State equation:

$\frac{{\mathrm{di}}_L}{dt}=\left\{\begin{array}{cc}\frac{u_s-U_o/2}{L},& KT\&le;t<KT+\frac{td}{2}\\ \frac{u_s}{L},& KT+\frac{td}{2}\&le;t<KT+T-\frac{td}{2}\\ \frac{u_s-U_o/2}{L},& KT+T-\frac{td}{2}\&le;t<KT+T\end{array}\right.$

It is hereby achieved that traditional control method structure chart as shown in Figure 3.

By comparison diagram 3 with Fig. 4 it appeared that the current tracking method improved makes improvement at following two aspects: 1. electric current Follow the tracks of: use phaselocked loop to extract the phase signal of voltage signal Us fundamental component, as the reference signal of current signal.When Us contains When having higher hamonic wave, its fundamental frequency signal is ideal sinusoidal signal.Ideally, power network current can effectively follow the tracks of this signal, Realize sinusoidal undistorted.2. complex controll: conventional PI control tracking accuracy is limited, introduces Repetitive controller and controls in parallel with PI, change Kind electric current loop tracking effect, improves current waveform quality.

As it is shown in figure 5, complex controll circuit configuration can be obtained.i_refFor current reference signal；i_LFor actual inductance electricity Stream, i_errFor offset current；z^-NFor cycle time delay process, Q (z) is auxiliary compensation device, and S (z) is controll plant compensator, z^kFor Differentiation element, PI is proportional plus integral control link, and K is that dutycycle arrives voltage ratio coefficient, and its value is U_o/2。

Concrete control method is to be multiplied phaselocked loop signal with Voltage loop output to obtain the reference signal of electric current loop, itself and electricity Stream sampled signal is subtracted each other, and obtains current error signal i_err.Under stable situation, error signal is less, and tracking effect is good.When going out When existing load changing or relatively large disturbances, actual current deviation reference value, now PI makes a response rapidly, improves tracking effect. One all after date, Repetitive controller detects tracking error i_err, interior mould carries out Cycle by Cycle for error and adds up, until final i_errBecome To in 0.The quickly response controlled by PI is followed the tracks of with the accurate of Repetitive controller, it is possible to achieve preferably controls effect, improves electricity Stream waveform quality.

Calculating Close-Loop Pulse Transfer Function in Fig. 5 is:

$\frac{i_L\left(z\right)}{i_{ref}\left(z\right)}=\frac{\{G_{PI}\left(z\right)-z^{-N}\&lsqb;{\mathrm{QG}}_{PI}\left(z\right)-C\left(z\right)\&rsqb;\}\frac{KG\left(z\right)}{1+G_{PI}\left(z\right)G\left(z\right)}}{1-z^{-N}\&lsqb;Q-C\left(z\right)\frac{KG\left(z\right)}{1+G_{PI}\left(z\right)G\left(z\right)}\&rsqb;}$

Wherein, C (z)=z^kS (z),

Order

Arrive system features equation: 1-z can be obtained fom the above equation^-N[Q-C (z) P (z)]=0

For discrete control system, all of and if only if characteristic equation are all located in unit circle, and system could be stablized. But fundamental frequency f in this programme_s=50Hz, sample frequency f_c=20kHz, N=400, belong to the equation of higher order, therefore uses another kind side Method judges stability.Above equation can be changed into:

z^N=Q-C (z) P (z)

If Z_i(i=1,2..., N) is characterized equation root, if Z_i＜ 1, then Z_i∣^N＜ 1.Then define H (z)=Q-C Z () P (z), so understands as H (z) ＜ 1, system is necessarily stable.

Q takes 0.95 according to engineering experience, and P (z) can regard the equivalent control object of system as, it is therefore desirable to reasonable in design Controlled device is compensated by penalty function S (z), to realize controlling target.From P (z) amplitude-frequency characteristic, deposit at medium and low frequency In the gain of-40dB, phase place does not exist delayed, and after designed second order filter S (z) should meet compensation, low frequency is cancelled out each other, The principle of high frequency attenuation.Can be seen that S (z) P (z) is zero in low-band gain, high band rapid decay, but S (z) P (z) exists There is certain delayed phase in Mid Frequency, therefore introduces differentiation element z^kCompensating phase place, this link is to amplitude-versus-frequency curve Without impact, the size of k depends on the phase offset that S (z) and P (z) is total.

As shown in Figure 6, for complex controll function characteristic.Can be seen that the z after compensation^kS (z) P (z) is at amplitude frequency curve On, zero gain at low frequency, decay rapidly at medium-high frequency.In terms of phase frequency curve, without phase offset at medium and low frequency.Finally Guarantee system is undamped for power frequency component, and the harmonic signal for power frequency has obvious inhibition.Analyze based on above, When sample frequency is 20kHz, for P (z), the penalty function designed herein is:

$C\left(z\right)=\frac{2.769z+1.569}{z^2-1.19z+0.2336}\&CenterDot;z^5$

Compared with traditional method, this programme can successfully manage voltage harmonic and the power quality problem such as subside.Can be effective Reduce current on line side harmonic content, improve current waveform quality, reduce output voltage ripple, maintain good reliability and stablize Property.

Modified model electric current tracking based on Repetitive controller to a kind of Vienna commutator that the present invention provides below Specifically verify.In order to verify correctness and the effectiveness of this programme, build the sample of three-phase four-wire system Vienna commutator Machine model, concrete model machine parameter is as shown in the table:

Experimental provision master controller uses the mode of DSP+FPGA, it is achieved full-digital control.Employing TMS320, F28335DSP chip realizes data process and core control algolithm as the main control chip of system, and FPGA completes the quick of data Transmitting-receiving.

By Fig. 7,8 it appeared that traditional method current waveform exists significantly distortion, and Fig. 9, use this programme in 10 After, current waveform distortion is obviously reduced, and waveform quality is more preferable, is effectively increased tracking accuracy.Can by contrast Figure 11 Yu Figure 12 To find, the DC voltage ripple of this programme is less, and output characteristics is more preferable.Therefore, this programme has more preferable harmonics restraint Characteristic, significantly reduces the distortion degree of power network current, and current tracking effect is more preferable, and waveform quality is significantly improved, Also can reduce DC voltage fluctuation so that direct current output is more stable simultaneously.

Electrical equipment, circuit, module and the electronic devices and components related in such scheme, in addition to special instruction, realize according to it Concrete function can select design generally in the art and scheme, it is also possible to select according to actual needs other design and side Case.

This programme for three-phase four-wire system Vienna commutator disclose a kind of modified model electric current based on Repetitive controller with Track method, compensate for Traditional control not enough of both reply power quality problem and current tracking effect, relate generally to Under several aspects: (1) for electrical network background harmonics and periodically subside, take pll output signal as current tracking signal, Mask voltage harmonic information；(2) introduce Repetitive controller in parallel with conventional PI control, appropriate design repetitive controller parameter, improve electricity Stream tracking effect.The line voltage that is applicable to of this programme occurs that the Vienna Rectifier in the case of disturbance has following Advantage:

(1) this programme mainly suppresses Voltage Harmonic for the impact of current on line side, effectively solves power quality problem, There are preferable reliability and stability, control simple and flexible simultaneously, it is easy to accomplish.

Current tracking precision the most of the present invention is high, and network side current waveform quality is good.

(3) present invention preserves the passage that PI controls, maintain good dynamic property.

(4) the reduction of current on line side harmonic content in the present invention, also reduces the fluctuation of DC voltage, it is ensured that good Output performance.

Therefore, this programme compared with prior art can be effectively improved current on line side quality, maintains DC-side Voltage Stabilization, There is prominent substantive distinguishing features and significantly progress.

The line voltage that is applicable to of this programme occurs that the Vienna Rectifier in the case of disturbance is not limited to tool Content disclosed in body embodiment, the technical scheme occurred in embodiment can be with individualism, it is also possible to mutually comprise, ability Field technique personnel combine, according to this programme, the simple alternative that common knowledge makes and fall within the scope of this programme.

Claims (2)

1. being applicable to the Vienna Rectifier in the case of disturbance occurs in line voltage, control system includes input Voltage U_SSampling module, input inductive current i_LSampling module, output filter capacitor voltage U_CSampling module, PI controller, PWM Module, input voltage U_SSampling module passes through abs rectifier bridge sampled input voltage U_SSignal and output filter capacitor voltage U_CSampling Module passes through PI_CSampled voltage ring output after controller process is multiplied and obtains electric current loop reference signal i_ref, electric current loop is with reference to letter Number i_refWith input inductive current i_LThe current signal that sampling module sampling obtains subtracts each other and obtains current error signal i_err, electric current is by mistake Difference signal i_errBeing decreased to stable operating point after being processed by PI controller, signal processes rear drive switching device by PWM module S action, is characterized in that the phase signal ginseng as current signal using phaselocked loop to extract input voltage Us signal fundamental component Examine signal, the harmonic component in shielding sampled voltage so that current tracking sine is undistorted.

The Vienna Rectifier being applicable in the case of disturbance occurs in line voltage the most according to claim 1, It is characterized in that, use Repetitive controller module formation in parallel with PI controller complex controll electric current loop, after a power frequency period, Being added up error by mould in Repetitive controller, improve electric current loop tracking effect, complex controll electric current loop includes cycle time delay Link z^-N, auxiliary compensation device Q (z), controll plant compensator S (z), differentiation element z^k, proportional plus integral control link PI, by phase-locked Ring signal is multiplied with Voltage loop output and obtains reference signal i of electric current loop_ref, i_refSubtract each other with current sampling signal and obtain electric current by mistake Difference signal i_err, load produces sudden change or disturbance, and actual current deviation reference value, PI controller adjusts current deviation, a cycle Rear Repetitive controller detects tracking error i_err, in Repetitive controller, that current error carries out Cycle by Cycle is cumulative until i for mould_errConvergence 0, Current waveform quality is improved with precisely following the tracks of of Repetitive controller module by the quickly response of PI controller.