CN2678226Y - Series mixed active power filter with fundamental bypass channel - Google Patents

Abstract

The utility model relates to a series mixed active power filter with fundamental bypass channel. The utility model has to solve problems that no matter whether an electric network and a load are balanced or not, an inverter of the series mixed active power filter with the fundamental bypass channel can be controlled to not flow over fundamental current ; the series mixed active power filter with the fundamental bypass channel can simultaneously restrain harmonic and avoid resonance generated by the fundamental bypass channel and the inverter; as a consequence, inverter capacity is reduced, the cost of a complete machine is reduced, and inverter efficiency is raised. The technical proposal of the utility model is mainly composed of a passive main circuit, the inverter, and a control circuit. The series mixed active power filter with the fundamental bypass channel is characterized in that: a current detection circuit of full fundamental is arranged in the control circuit; the circuit adopts the structure circuit of double dq transformation of positive and negative rotary ; the inverter is composed of a three-phase inverter, a low-pass filter, an isolating and driving circuit, an energy storage capacitor, and a charging circuit composed of an insulating transformer, a filtering inductor, and a three-phase rectifying bridge.

Description

The series hybrid active power filter of tape base bourbon paths

Technical field

This patent belongs to the electric harmonic abatement equipment, relates to the series hybrid active power filter of tape base bourbon paths.

Background technology

Owing to can overcome many shortcomings of traditional passive filter, Active Power Filter-APF (APF) has obtained people's broad research since proposing the seventies.But active filter also has a fatal weakness: cost is too high.This has become the bottleneck that Active Power Filter-APF is applied.So, develop stable and reliable for performance, compensation effect good and cheaply Active Power Filter-APF be one of main direction of studying of present Active Power Filter-APF.

1991, Japan scholar Toshihiko Tanaka and Hirofumi Akagi have proposed a kind of series hybrid active power filter (Toshihiko Tanaka that has the fundamental current bypass channel, Hirofumi Akagi, A new combined system ofseries active and shunt passive filters aiming at harmonic compensation for large capacity thyristorconverters, IECON ' 91, Page (s): 723-728, vol.1).Be characterized in that the high-pressure side (being inverter side) at coupling transformer has increased a resonance in the LC of mains frequency passage (hereinafter to be referred as the PPF1 passage).First-harmonic composition in the power network current can be flow through by this passage, and without inverter.Inverter only need provide harmonic voltage and flow through the mains by harmonics electric current, therefore, can reduce the capacity of inverter greatly, can reduce the cost of APF complete machine then, improve the efficient of complete machine, and it has good filtering performance.In addition, the PPF1 passage makes the protection of system become easily, even because inverter breaks down, the PPF1 passage still can provide the passage of energy flux to load, is unlikely to make the load outage.

Control method in the literary composition is to allow inverter that the harmonic current of electrical network is a bigger impedance, makes the load harmonic current flow to the passive filter group as far as possible, reduces the harmonic current that flows to electrical network; Simultaneously, the fundamental current that flows through inverter itself is a bigger impedance, makes the fundamental current of electrical network flow through from the PPF1 passage as much as possible, and the inverter of can not flowing through.The detection of mains by harmonics electric current and inverter fundamental current is based on the method for instantaneous reactive power theory in the literary composition, this method is in line voltage symmetry and not when distortion and load current symmetry, can be so that the electrical network fundamental current all flows through from the PPF1 passage, and can not flow through inverter, thereby reduce the capacity of inverter.But, in actual applications, line voltage generally all has distortion and asymmetry to a certain degree, load current is difficult to guarantee all to be symmetrical at any time especially, at this moment, if adopt the control method in the literary composition, because its " fundamental current " that detects is the fundamental positive sequence electric current in fact just, and in fact comprised fundamental negative sequence current in " harmonic current " that it detects, the electrical network negative-sequence current will amplify by resonance between PPF1 passage and inverter as a result, cause and flow through very big electrical network fundamental current in the inverter.Like this, the major advantage of the series hybrid active power filter of tape base bourbon paths: reduce the capacity of inverter, also just can't realize.Main cause that this Active Power Filter-APF is not applied in practice that Here it is.

Summary of the invention

The purpose of this utility model is the series hybrid active power filter that proposes a kind of tape base bourbon paths, make it no matter whether equal control inverter does not flow through fundamental current for electrical network and load balance, when suppressing harmonic wave, avoid fundamental current bypass channel and inverter generation resonance, reduce the shared capacity of active part.

For achieving the above object, the technical scheme of taking is that the fundamental Current's Detection circuit based on the two dq conversion of positive and reverse return is arranged in the control circuit of series hybrid active power filter of tape base bourbon paths.

Because the fundamental Current's Detection circuit based on the two dq conversion of positive and reverse return can distort at line voltage, when asymmetric and load current is asymmetric, all the fundametal compoment in power network current and the inverter current intactly can be detected, so when being applied to the control of series hybrid active power filter of tape base bourbon paths, between PPF1 passage and the inverter first-harmonic resonance can not take place, the power network current fundametal compoment all flows through from the PPF1 passage, and can not flow through inverter, thereby greatly reduce the capacity of inverter.The invention enables the series hybrid active power filter of tape base bourbon paths can in the three-phase three-wire system load of reality or three-phase four-wire system load, realize the advantage that the shared capacity of its active part is little, cost is low.

Description of drawings

Fig. 1 is the series hybrid active power filter schematic diagram that is applied to the tape base bourbon paths of three-phase three-wire system load;

Fig. 2 is that the inverter reference signal that the utility model uses is calculated and pwm signal generative circuit schematic diagram;

Fig. 3 is based on the three-phase three-wire system system fundamental Current's Detection circuit theory diagrams of the two dq conversion of positive and reverse return;

Fig. 4 is load current and spectrum analysis thereof;

Fig. 5 is that power network current electric current and frequency spectrum thereof are analysed;

Fig. 6 is PPF1 channel current and spectrum analysis thereof;

Fig. 7 is transformer current and spectrum analysis thereof.

Embodiment

Describe technical scheme in detail with reference to accompanying drawing:

As shown in Figure 1, the series hybrid active power filter of the tape base bourbon paths that relates to of the utility model is made up of passive main circuit, inverter, control circuit etc.

Passive main circuit comprises that coupling transformer MT, fundamental current bypass channel are PPF1 passage, passive filter group PPFs.

Coupling transformer is a three-phase transformer, or is made up of three single-phase transformers.

The PPF1 passage is made up of the resonant tank of inductor and capacitor, for the electrical network fundamental current provides the low impedance path, wherein the second order resonant circuit of being made up of inductor L1 and capacitor C1 is fairly simple, generally can meet the demands, and L1, C1 are tuned in the electrical network fundamental frequency.According to the size of capacity, PPF1 can be connected in parallel on the former limit (side that links to each other with inverter) of coupling transformer, also is the secondary (side that links to each other with electrical network) that can be connected in parallel on coupling transformer, cuts both ways.

Passive filter group PPFs is made up of low order single tuned filter group and high pass filter.Wherein low order single tuned filter group can be by 5 times, and 7 times, 11 times, 13 compositions also can be only by 5 times, 7 compositions.It is more effective that the former suppresses 11 times, 13 times.The latter is then fairly simple, can simplify circuit, reduce cost for the occasion that the nonlinear load high order harmonic component is few.

Inverter circuit comprises converter main circuit INV, storage capacitor C _Dc, low pass filter LPF, by inductor L _r, capacitor C _rForm, be used for switch harmonic, drive circuit that the filtering inverter produces, and by isolating transformer T _CR, filter inductance L _CR, three-phase commutation bridge B _CRThe charging circuit of forming.Converter main circuit INV can be made of a three-phase inverter or three single-phase inverters.

Control circuit is made up of current sensor CT, voltage sensor VT, phase-locked loop pll, the calculating of inverter reference signal and pwm signal generative circuit etc.Phase-locked loop pll circuit output electrical network AB line voltage v _AbZero cross signal and frequency-doubled signal thereof, the pointer of these signals sine table sin (wt) and cosine table cos (wt) during as first-harmonic/Harmonics Calculation.

Fig. 2 is that the inverter reference signal that the utility model uses is calculated and pwm signal generative circuit schematic diagram.At first, power network current i _S(comprise i _Sa, i _Sb, i _Sc) and inverter current iC (comprise i _Ca, i _Cb, i _Cc) the full fundamental Current's Detection circuit of input, detect power network current fundametal compoment i _Sf(comprise i _Saf, i _Sbf, i _Scf) and inverter current fundametal compoment i _Cf(comprise i _Caf, i _Cbf, i _Ccf), then from power network current i _SDeduct power network current fundametal compoment i _Sf, obtain power network current harmonic component i _Sh(comprise i _Sah, i _Sbh, i _Sch), i _ShTake advantage of in COEFFICIENT K _Sh(inverter is to the impedance of mains by harmonics electric current) obtains inverter reference signal 1V _C1i _CfTake advantage of in COEFFICIENT K _Cf(inverter is to the impedance of inverter fundamental current) obtains inverter reference signal 2V _C2, both respective components additions obtain the complete reference signal v of inverter ^*(being modulation signal) obtains pwm signal PWM1～PWM6 through certain method (such as triangular modulation, space vector modulation, stagnant ring control etc.), and these signals amplify the rear drive inverter through isolating.Circuit shown in Figure 2 can be realized with hardware, also can realize with software.

The utility model key technology is that full fundamental Current's Detection circuit is set in control circuit, adopt the structural circuit of the two dq conversion of positive and reverse return, as shown in Figure 3: it is made up of positive sequence dq conversion passage and negative phase-sequence dq conversion passage two parts, comprise four adder A, B, C, D, four low pass filter LPF, three or two conversion C ₃₂, two or three conversion C ₂₃, positive sequence dq conversion C _Dq+, negative phase-sequence dq conversion C _Dq-, positive sequence dq inverse transformation C _Dq+ ^-1, negative phase-sequence dq inverse transformation C _Dq- ^-1, A, B biphase current i _a, i _bInput summer A after anti-phase obtains C phase current i _c, i then _a, i _b, i _cThrough three or two conversion, positive sequence dq conversion C ₃₂C _Dq+ ^-1, output positive sequence d axle component i _D+With positive sequence q axle component i _Q+, i _D+, i _Q+Meet low pass filter LPF respectively, the DC component i that output is corresponding _D+, i _Q+, i _D+, i _Q+Through positive sequence dq inverse transformation, two or three conversion C _Dq+ ^-1C ₂₃, output positive sequence fundametal compoment i _Af+, i _Bf, i _Cf+, simultaneously, i _a, i _b, i _cThrough three or two conversion and negative phase-sequence dq conversion C ₃₂C _Dq+ ^-1, output negative phase-sequence d axle component i _D-With negative phase-sequence q axle component i _Q-, i _D-, i _Q-Meet low pass filter LPF respectively, the DC component i that output is corresponding _D-, i _Q-, i _D-, i _Q-Meet negative phase-sequence dq inverse transformation and two or three conversion C _Dq- ^-1C ₂₃, output negative phase-sequence fundametal compoment i _Af-, i _Bf-, i _Cf-, last, i _Af+And i _Af-Input summer B obtains A phase fundamental current i _Af, i _Bf+And i _Bf-Input summer C obtains B phase fundamental current i _Bf, i _Cf+And i _Cf-Input summer D obtains C phase fundamental current i _CfWherein used transformation matrix is:

$C_{32}=\sqrt{\frac{2}{3}}\left[\begin{array}{ccc}1& -1/2& -1/2\\ 0& \sqrt{3}/2& -\sqrt{3}/2\end{array}\right]$

$C_{23}=\sqrt{\frac{2}{3}}\left[\begin{array}{cc}1& 0\\ -1/2& \sqrt{3}/2\\ -1/2& -\sqrt{3}/2\end{array}\right]$

$C_{{\mathrm{dq}}^{+}}\left(\mathrm{wt}\right)=C_{{\mathrm{dq}}^{+}}^{-1}\left(\mathrm{wt}\right)=\left[\begin{array}{cc}\sin \left(\mathrm{\ωt}\right)& -\cos \left(\mathrm{\ωt}\right)\\ -\cos \left(\mathrm{\ωt}\right)& -\sin \left(\mathrm{\ωt}\right)\end{array}\right]$

$C_{{\mathrm{dq}}^{-}}\left(\mathrm{wt}\right)=C_{{\mathrm{dq}}^{-}}^{-1}\left(\mathrm{wt}\right)=\left[\begin{array}{cc}\sin \left(\mathrm{\ωt}\right)& \cos \left(\mathrm{\ωt}\right)\\ -\cos \left(\mathrm{\ωt}\right)& \sin \left(\mathrm{\ωt}\right)\end{array}\right]$

Wherein, sin (wt) and cos (wt) are through phase-locked loop pll and synchronous unit sinusoidal signal and the unit cosine signal of electrical network fundamental frequency w; Electric current " i _a, " i _b", " i _cRefer to power network current i _Sa, i _Sb, i _ScOr inverter current i _Ca, i _Cb, i _Cc

The present invention can be used for the three-phase three-wire system system, also can be applied to three-phase four-wire system.

The present invention sees Fig. 4～Fig. 7 to the experimental result of unbalanced load.

Comparison diagram 4 and Fig. 5: the resultant distortion rate (THD) of load current is about 40%, and the THD of power network current is about 8% after the filtering, and filter effect is good.

Comparison diagram 6 and Fig. 7 can see, the PPF1 passage fundamental current that only circulates basically, the inverter harmonic current that only circulates, and harmonic current is far smaller than fundamental current.Only account for a very little part in the power network current, reduced the capacity of inverter effectively, improved efficient.

Claims (3)

1. the series hybrid active power filter of tape base bourbon paths mainly is made up of passive main circuit, inverter and control circuit, it is characterized in that being provided with in the control circuit full fundamental Current's Detection circuit.

2. press the series hybrid active power filter of the described tape base bourbon of claim 1 paths, it is characterized in that full fundamental Current's Detection circuit is the structural circuit with the two dq conversion of positive and reverse return: it is made up of positive sequence dq conversion passage and negative phase-sequence dq conversion passage two parts, comprise four adders (A, B, C, D), four low pass filters (LPF), three or two conversion (C ₃₂), two or three conversion (C ₂₃), positive sequence dq conversion (C _Dq+), negative phase-sequence dq conversion (C _Dq-), positive sequence dq inverse transformation (C _Dq+ ^-1) and negative phase-sequence dq inverse transformation (C _Dq- ^-1) all circuit, A, B biphase current (i _a), (i _b) input summer A after anti-phase, obtain C phase current (i _c), then, three-phase current (I _a), (i _b), (i _c) through three or two conversion, positive sequence dq conversion (C ₃₂C _Dq+ ^-1), output positive sequence d axle component (i _D+) and positive sequence q axle component (i _Q+), i _D+, i _Q+Connect low pass filter (LPF) respectively, the DC component (i that output is corresponding _D+), (i _Q+), i _D+, i _Q+Through positive sequence dq inverse transformation, two or three conversion (C _Dq+ ^-1C ₂₃), output positive sequence fundametal compoment (i _Af+, i _Bf+, i _Cf+), simultaneously, i _a, i _b, i _cThrough three or two conversion and negative phase-sequence dq conversion (C ₃₂C _Dq+ ^-1), output negative phase-sequence d axle component (i _D-) and negative phase-sequence q axle component (i _Q-), i _D-, i _Q-Connect low pass filter (LPF) respectively, the DC component (i that output is corresponding _D-), (i _Q-), i _D-, i _Q-Meet negative phase-sequence dq inverse transformation and two or three conversion (C _Dq- ^-1C ₂₃), output negative phase-sequence fundametal compoment (i _Af-, i _Bf-, i _Cf-), i _Af+And i _Af-Input summer B obtains A phase fundamental current (i _Af), i _Bf+And i _Bf-Input summer C obtains B phase fundamental current (i _Bf), i _Cf+And i _Cf-Input summer D obtains C phase fundamental current (i _Cf), wherein used transformation matrix is:

$C_{32}=\sqrt{\frac{2}{3}}\left[\begin{array}{ccc}1& -1/2& -1/2\\ 0& \sqrt{3}/2& -\sqrt{3}/2\end{array}\right]$

$C_{23}=\sqrt{\frac{2}{3}}\left[\begin{array}{cc}1& 0\\ -1/2& \sqrt{3}/2\\ -1/2& -\sqrt{3}/2\end{array}\right]$

$C_{{\mathrm{dq}}^{+}}\left(\mathrm{wt}\right)=C_{{\mathrm{dq}}^{+}}^{-1}\left(\mathrm{wt}\right)=\left[\begin{array}{cc}\sin \left(\mathrm{\ωt}\right)& -\cos \left(\mathrm{\ωt}\right)\\ -\cos \left(\mathrm{\ωt}\right)& -\sin \left(\mathrm{\ωt}\right)\end{array}\right]$

$C_{d{q}^{-}}\left(\mathrm{wt}\right)=C_{{\mathrm{dq}}^{-}}^{-1}\left(\mathrm{wt}\right)=\left[\begin{array}{cc}\sin \left(\mathrm{\ωt}\right)& \cos \left(\mathrm{\ωt}\right)\\ -\cos \left(\mathrm{\ωt}\right)& \sin \left(\mathrm{\ωt}\right)\end{array}\right]$

3. by the series hybrid active power filter of the described tape base bourbon of claim 1 paths, it is characterized in that inverter is by three-phase inverter (INV), low pass filter (LPF), isolation and drive circuit, storage capacitor C _Dc, and by isolating transformer (T _CR), filter inductance (L _CR), three-phase commutation bridge (B _CR) charging circuit formed forms.

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