CN104122432A - Three-level active power filter (APF) reference current detection method suitable for distorted or unbalanced situation - Google Patents

Abstract

The invention discloses a three-level active power filter (APF) reference current detection method suitable for a distorted or unbalanced situation, relates to the field of three-level parallel APF reference current detection under a power grid distorted or unbalanced situation, and solves the problem of low detection accuracy of the APF reference current detection method based on an instantaneous power theory under the non-sine or unbalanced situation of power grid voltage. The method is used for performing resonant current separation. The detection method can run effectively in an alpha-beta coordinate system under a voltage distorted or unbalanced situation, and high compensation characteristic is realized for an APF. Based on a high-selectivity filter (HSF), the method can be applied to a distorted or unbalanced power grid environment, and resonant compensation and power factor correction can be effectively performed through the APF, thereby increasing the reference current detection accuracy and ensuring that the power grid current and the power grid voltage are at the same phase. The method is suitable for detecting the reference current of a three-level APF under a distorted or unbalanced situation.

Description

A kind of be applicable to distortion or uneven situation under three level active wave filter reference current detection methods

Technical field

The present invention relates to three level parallel APF reference current detection fields in electrical network distortion or uneven situation.

Background technology

Along with the extensive application of nonlinear load, for example diode rectifier bridge, thyristor rectifier device and arrangements for speed regulation, electric system has been subject to serious pollution.Conventionally, Passive LC wave filter is used to eliminate current harmonics and improves power factor.But passive filter has a lot of shortcomings, for example compensation capacity is fixed, volume large and resonance problems.In order to solve appeal problem, active filter is the studied harmonic carcellation and overcome other power quality problems of being used for.

On the other hand, diode clamp type three-level converter is widely used in industrial circle, such as PWM rectification, motor driving and uninterrupted power source etc.It has the following advantages: the aberration rate of output voltage and electric current is low, ripple filter volume is little, unit efficiency high-low voltage stress and low common mode voltage.

At present, the most competitive in harmonic compensation field is three level parallel active filters, and the order of accuarcy of compensate for reference Current calculation is one of principal element affecting active filter performance.Instantaneous power theory, notch filter all have a large amount of application, but when line voltage non-sinusoidal or imbalance, these methods can reduce the performance of active filter.When line voltage is sinusoidal, the detection method based on Power Theory is best selection.Yet, in non-sinusoidal voltage situation, offset current waveform quality degradation.

Summary of the invention

The present invention, in order to solve line voltage non-sinusoidal or the low problem of APF reference current detection method accuracy of detection based on instantaneous power theory when uneven, has proposed a kind of three level active wave filter reference current detection methods in distortion or uneven situation that are applicable to.

A kind of be applicable to distortion or uneven situation under three level active wave filter reference current detection methods comprise the following steps:

Step 1, by the A phase voltage u in APF and electrical network points of common connection _sa, B phase voltage u _sbwith C phase voltage u _scthrough three phase transformation two-phases, obtain the voltage u of APF and electrical network points of common connection under α β coordinate _{s α}and u _{s β};

Step 2, by the A phase current i in load current _la, B phase current i _lbwith C phase current i _lcthrough three phase transformation two-phases, obtain load current i under α β coordinate _{l α}and i _{l β};

Step 3, by the voltage u of APF and electrical network points of common connection under α β coordinate _{s α}and u _{s β}through highly selective filter, carry out filtering, the fundametal compoment of the voltage of APF and electrical network points of common connection under acquisition α β coordinate with

Step 4, by the load current i of APF and electrical network points of common connection under α β coordinate _{l α}and i _{l β}through highly selective filter, carry out filtering, the fundametal compoment of the load current of APF and electrical network points of common connection under acquisition α β coordinate with

Step 5, by load current i under α β coordinate _{l α}and i _{l β}respectively with the fundametal compoment of load current with subtract each other, obtain the harmonic component i of load current _{h α}and i _{h β};

The fundametal compoment of step 6, the voltage by APF under α β coordinate and electrical network points of common connection with harmonic component i with load current _{h α}and i _{h β}, obtain instantaneous real power fluctuation part fluctuation part with instantaneous reactive power

The fundametal compoment of step 7, the voltage by APF under α β coordinate and electrical network points of common connection with fundametal compoment with load current with obtain the fundametal compoment of instantaneous reactive power

Step 8, Acquisition Circuit upper and lower bridge arm DC voltage u _dC1and u _dC2, calculate u _dC1with u _dC2difference, and using this difference as feedback and DC deviation do subtraction Output rusults, by regulator, this result is carried out to regulating error, adjusted amount p _c, and by p _cfluctuation part with instantaneous real power output variable superposes;

Step 9, by the fluctuation part of instantaneous reactive power fundametal compoment with instantaneous reactive power output variable superposes;

The fundametal compoment of the voltage of APF and electrical network points of common connection under the variable of step 10, the variable of exporting by step 8, step 9 output and α β coordinate with obtain the current reference value of APF under α β coordinate with

Step 11, step 10 is obtained to the current reference value of APF under α β coordinate with carry out two-phase and to the conversion of three-phase, obtain the A phase reference current of APF b phase reference current c phase reference current realize the detection of reference current.

Beneficial effect: the present invention proposes a kind of improved instantaneous reactive power theory method based on highly selective filter (HSF), be used for carrying out harmonic current separation, this detection method is under α β coordinate system, in voltage distortion or unbalanced situation, can effectively work, make APF obtain compensation characteristic well, reference current is one of key factor affecting active filter compensation performance, the present invention is directed to diode clamp type three level active wave filters and proposed a kind of new reference current detection, the method is based on highly selective filter (HSF), can be applicable under distortion or unbalanced power grid environment, make active filter compensation harmonic and carry out power factor correction effectively, improved reference current accuracy of detection, guarantee power network current keep sinusoidal and with line voltage same-phase.

Accompanying drawing explanation

Fig. 1 is a kind of principle schematic that is applicable to three level active wave filter reference current detection methods in distortion or uneven situation described in embodiment one;

Fig. 2 is the principle schematic of highly selective filter;

Fig. 3 is the filter effect figure of three level active wave filters under balance;

Fig. 4 is system three-phase voltage oscillogram in uneven situation;

Fig. 5 is system three-phase current oscillogram in uneven situation;

Fig. 6 is system three-phase current oscillogram after three level active filter filterings in uneven situation.

Embodiment

Embodiment one, a kind of be applicable to distortion or uneven situation under three level active wave filter reference current detection methods, it is characterized in that, it comprises the following steps:

Step 1, by the A phase voltage u in APF and electrical network points of common connection _sa, B phase voltage u _sbwith C phase voltage u _scthrough three phase transformation two-phases, obtain the voltage u of APF and electrical network points of common connection under α β coordinate _{s α}and u _{s β};

Step 2, by the A phase current i in load current _la, B phase current i _lbwith C phase current i _lcthrough three phase transformation two-phases, obtain load current i under α β coordinate _{l α}and i _{l β};

Step 3, by the voltage u of APF and electrical network points of common connection under α β coordinate _{s α}and u _{s β}through highly selective filter, carry out filtering, the fundametal compoment of the voltage of APF and electrical network points of common connection under acquisition α β coordinate with

Step 4, by the load current i of APF and electrical network points of common connection under α β coordinate _{l α}and i _{l β}through highly selective filter, carry out filtering, the fundametal compoment of the load current of APF and electrical network points of common connection under acquisition α β coordinate with

Step 5, by load current i under α β coordinate _{l α}and i _{l β}respectively with the fundametal compoment of load current with subtract each other, obtain the harmonic component i of load current _{h α}and i _{h β};

The fundametal compoment of step 6, the voltage by APF under α β coordinate and electrical network points of common connection with harmonic component i with load current _{h α}and i _{h β}, obtain instantaneous real power fluctuation part fluctuation part with instantaneous reactive power

The fundametal compoment of step 7, the voltage by APF under α β coordinate and electrical network points of common connection with fundametal compoment with load current with obtain the fundametal compoment of instantaneous reactive power

Step 8, Acquisition Circuit upper and lower bridge arm DC voltage u _dC1and u _dC2, calculate u _dC1with u _dC2difference, and using this difference as feedback and DC deviation do subtraction Output rusults, by regulator, this result is carried out to regulating error, adjusted amount p _c, and by p _cfluctuation part with instantaneous real power output variable superposes;

Step 9, by the fluctuation part of instantaneous reactive power fundametal compoment with instantaneous reactive power output variable superposes;

The fundametal compoment of the voltage of APF and electrical network points of common connection under the variable of step 10, the variable of exporting by step 8, step 9 output and α β coordinate with obtain the current reference value of APF under α β coordinate with

Step 11, step 10 is obtained to the current reference value of APF under α β coordinate with carry out two-phase and to the conversion of three-phase, obtain the A phase reference current of APF b phase reference current c phase reference current realize the detection of reference current.

Embodiment two, a kind of three level active wave filter reference current detection methods in distortion or uneven situation that are applicable to according to claim 1, is characterized in that, described in step 1 by the A phase voltage u in APF and electrical network points of common connection _sa, B phase voltage u _sbwith C phase voltage u _scthrough three phase transformation two-phases, obtain the voltage u of APF and electrical network points of common connection under α β coordinate _{s α}and u _{s β}process be:

$\left[\begin{array}{c}{u}_{\mathrm{s\α}}\\ u_{\mathrm{s\β}}\end{array}\right]=\frac{2}{3}\left[\begin{array}{ccc}1& -1/2& 1/2\\ 0& \sqrt{3}/2& -\sqrt{3}/2\end{array}\right]\left[\begin{array}{c}{u}_{\mathrm{sa}}\\ u_{\mathrm{sb}}\\ u_{\mathrm{sc}}\end{array}\right].$

Embodiment three, according to claim 1 a kind of be applicable to distortion or uneven situation under three level active wave filter reference current detection methods, it is characterized in that, in step 2 by the A phase current i in load current _la, B phase current i _lbwith C phase current i _lcthrough three phase transformation two-phases, obtain load current i under α β coordinate _{l α}and i _{l β}process be;

$\left[\begin{array}{c}{i}_{\mathrm{L\α}}\\ i_{\mathrm{L\β}}\end{array}\right]=\frac{2}{3}\left[\begin{array}{ccc}1& -1/2& 1/2\\ 0& \sqrt{3}/2& -\sqrt{3}/2\end{array}\right]\left[\begin{array}{c}{i}_{\mathrm{La}}\\ i_{\mathrm{Lb}}\\ i_{\mathrm{Lc}}\end{array}\right].$

Embodiment four, according to claim 1 a kind of be applicable to distortion or uneven situation under three level active wave filter reference current detection methods, it is characterized in that, in step 3 by the voltage u of APF and electrical network points of common connection under α β coordinate _{s α}and u _{s β}through highly selective filter, carry out filtering, the fundametal compoment of the voltage of APF and electrical network points of common connection under acquisition α β coordinate with process be:

${\hat{X}}_{\mathrm{\α}}\left(s\right)=\frac{K(s+K)}{{(s+K)}^2+{\mathrm{\ω}}_c^2}{X}_{\mathrm{\α}}\left(s\right)-\frac{K{\mathrm{\ω}}_c}{{(s+K)}^2+{\mathrm{\ω}}_c^2}{X}_{\mathrm{\β}}\left(s\right)$

${\hat{X}}_{\mathrm{\β}}\left(s\right)=-\frac{K{\mathrm{\ω}}_c}{{(s+K)}^2+{\mathrm{\ω}}_c^2}{X}_{\mathrm{\α}}\left(s\right)+\frac{K(s+K)}{{(s+K)}^2+{\mathrm{\ω}}_c^2}{X}_{\mathrm{\β}}\left(s\right)$

Wherein, X is voltage, ω _c=2 π f _c, f _c=50Hz.

Embodiment five, according to claim 1 a kind of be applicable to distortion or uneven situation under three level active wave filter reference current detection methods, it is characterized in that, in step 4 by the load current i of APF and electrical network points of common connection under α β coordinate _{l α}and i _{l β}through highly selective filter, carry out filtering, the fundametal compoment of the load current of APF and electrical network points of common connection under acquisition α β coordinate with process be:

${\hat{X}}_{\mathrm{\α}}\left(s\right)=\frac{K(s+K)}{{(s+K)}^2+{\mathrm{\ω}}_c^2}{X}_{\mathrm{\α}}\left(s\right)-\frac{K{\mathrm{\ω}}_c}{{(s+K)}^2+{\mathrm{\ω}}_c^2}{X}_{\mathrm{\β}}\left(s\right)$

${\hat{X}}_{\mathrm{\β}}\left(s\right)=-\frac{K{\mathrm{\ω}}_c}{{(s+K)}^2+{\mathrm{\ω}}_c^2}{X}_{\mathrm{\α}}\left(s\right)+\frac{K(s+K)}{{(s+K)}^2+{\mathrm{\ω}}_c^2}{X}_{\mathrm{\β}}\left(s\right)$

Wherein, X is electric current, ω _c=2 π f _c, f _c=50Hz.

Embodiment six, a kind of three level active wave filter reference current detection methods in distortion or uneven situation that are applicable to according to claim 1, it is characterized in that the fundametal compoment of the voltage by APF under α β coordinate and electrical network points of common connection in step 6 with harmonic component i with load current _{h α}and i _{h β}, obtain instantaneous real power fluctuation part fluctuation part with instantaneous reactive power process be:

$\hat{p}={\hat{v}}_{\mathrm{\α}}{i}_{\mathrm{h\α}}+{\hat{v}}_{\mathrm{\β}}{i}_{\mathrm{h\β}}$

$\hat{q}={-\hat{v}}_{\mathrm{\β}}{i}_{\mathrm{h\α}}+{\hat{v}}_{\mathrm{\α}}{i}_{\mathrm{h\β}}.$

Embodiment seven, a kind of three level active wave filter reference current detection methods in distortion or uneven situation that are applicable to according to claim 1, it is characterized in that the fundametal compoment of the voltage by APF under α β coordinate and electrical network points of common connection in step 7 with fundametal compoment with load current with obtain the fundametal compoment of instantaneous reactive power process be:

$\hat{q}={-\hat{v}}_{\mathrm{\β}}{\hat{i}}_{\mathrm{\α}}+{\hat{v}}_{\mathrm{\α}}{\hat{i}}_{\mathrm{\β}}.$

Embodiment eight, a kind of three level active wave filter reference current detection methods in distortion or uneven situation that are applicable to according to claim 1, it is characterized in that the fundametal compoment of the voltage of APF and electrical network points of common connection under the variable of the variable of exporting by step 8 in step 10, step 9 output and α β coordinate with obtain the current reference value of APF under α β coordinate with process be:

$i_{\mathrm{\α}}^{*}=\frac{{\hat{v}}_{\mathrm{\α}}}{{\hat{v}}_{\mathrm{\α}}^2{\hat{v}}_{\mathrm{\β}}^2}(\hat{p}+p_c)-\frac{{\hat{v}}_{\mathrm{\β}}}{{\hat{v}}_{\mathrm{\α}}^2+{\hat{v}}_{\mathrm{\β}}^2}(\hat{q}+\stackrel{\‾}{q})$

$i_{\mathrm{\β}}^{*}=\frac{{\hat{v}}_{\mathrm{\β}}}{{\hat{v}}_{\mathrm{\α}}^2{\hat{v}}_{\mathrm{\β}}^2}(\hat{p}+p_c)+\frac{{\hat{v}}_{\mathrm{\α}}}{{\hat{v}}_{\mathrm{\α}}^2+{\hat{v}}_{\mathrm{\β}}^2}(\hat{q}+\stackrel{\‾}{q}).$

Embodiment nine, a kind of three level active wave filter reference current detection methods in distortion or uneven situation that are applicable to according to claim 1, is characterized in that, in step 11, step 10 obtained to the current reference value of APF under α β coordinate with carry out two-phase and to the conversion of three-phase, obtain the A phase reference current of APF b phase reference current c phase reference current process be:

$\left[\begin{array}{c}{i}_a^{*}\\ i_b^{*}\\ i_c^{*}\end{array}\right]=\frac{2}{3}\left[\begin{array}{cc}1& 0\\ -1/2& \sqrt{3}/2\\ -1/2& -\sqrt{3}/2\end{array}\right]\left[\begin{array}{c}{i}_{\mathrm{\α}}^{*}\\ i_{\mathrm{\β}}^{*}\end{array}\right].$

In order to verify, be applicable to three level active wave filter reference current detection methods in distortion or uneven situation, APF practical application effect, carried out related experiment, Fig. 3-Fig. 6 be respectively under balance and uneven situation under experimental result, therefrom can find out, APF can obtain satisfied compensation effect.

Claims (9)

1. be applicable to three level active wave filter reference current detection methods in distortion or uneven situation, it is characterized in that, it comprises the following steps:

Step 1, by the A phase voltage u in APF and electrical network points of common connection _sa, B phase voltage u _sbwith C phase voltage u _scthrough three phase transformation two-phases, obtain the voltage u of APF and electrical network points of common connection under α β coordinate _{s α}and u _{s β};

Step 2, by the A phase current i in load current _la, B phase current i _lbwith C phase current i _lcthrough three phase transformation two-phases, obtain load current i under α β coordinate _{l α}and i _{l β};

Step 3, by the voltage u of APF and electrical network points of common connection under α β coordinate _{s α}and u _{s β}through highly selective filter, carry out filtering, the fundametal compoment of the voltage of APF and electrical network points of common connection under acquisition α β coordinate with

Step 4, by the load current i of APF and electrical network points of common connection under α β coordinate _{l α}and i _{l β}through highly selective filter, carry out filtering, the fundametal compoment of the load current of APF and electrical network points of common connection under acquisition α β coordinate with

Step 5, by load current i under α β coordinate _{l α}and i _{l β}respectively with the fundametal compoment of load current with subtract each other, obtain the harmonic component i of load current _{h α}and i _{h β};

The fundametal compoment of step 6, the voltage by APF under α β coordinate and electrical network points of common connection with harmonic component i with load current _{h α}and i _{h β}, obtain instantaneous real power fluctuation part fluctuation part with instantaneous reactive power

The fundametal compoment of step 7, the voltage by APF under α β coordinate and electrical network points of common connection with fundametal compoment with load current with obtain the fundametal compoment of instantaneous reactive power

Step 8, Acquisition Circuit upper and lower bridge arm DC voltage u _dC1and u _dC2, calculate u _dC1with u _dC2difference, and using this difference as feedback and DC deviation do subtraction Output rusults, by regulator, this result is carried out to regulating error, adjusted amount p _c, and by p _cfluctuation part with instantaneous real power output variable superposes;

Step 9, by the fluctuation part of instantaneous reactive power fundametal compoment with instantaneous reactive power output variable superposes;

The fundametal compoment of the voltage of APF and electrical network points of common connection under the variable of step 10, the variable of exporting by step 8, step 9 output and α β coordinate with obtain the current reference value of APF under α β coordinate with

Step 11, step 10 is obtained to the current reference value of APF under α β coordinate with carry out two-phase and to the conversion of three-phase, obtain the A phase reference current of APF b phase reference current c phase reference current realize the detection of reference current.

2. a kind of three level active wave filter reference current detection methods in distortion or uneven situation that are applicable to according to claim 1, is characterized in that, described in step 1 by the A phase voltage u in APF and electrical network points of common connection _sa, B phase voltage u _sbwith C phase voltage u _scthrough three phase transformation two-phases, obtain the voltage u of APF and electrical network points of common connection under α β coordinate _{s α}and u _{s β}process be:

$\left[\begin{array}{c}{u}_{\mathrm{s\α}}\\ u_{\mathrm{s\β}}\end{array}\right]=\frac{2}{3}\left[\begin{array}{ccc}1& -1/2& 1/2\\ 0& \sqrt{3}/2& -\sqrt{3}/2\end{array}\right]\left[\begin{array}{c}{u}_{\mathrm{sa}}\\ u_{\mathrm{sb}}\\ u_{\mathrm{sc}}\end{array}\right].$

According to claim 1 a kind of be applicable to distortion or uneven situation under three level active wave filter reference current detection methods, it is characterized in that, in step 2 by the A phase current i in load current _la, B phase current i _lbwith C phase current i _lcthrough three phase transformation two-phases, obtain load current i under α β coordinate _{l α}and i _{l β}process be;

$\left[\begin{array}{c}{i}_{\mathrm{L\α}}\\ i_{\mathrm{L\β}}\end{array}\right]=\frac{2}{3}\left[\begin{array}{ccc}1& -1/2& 1/2\\ 0& \sqrt{3}/2& -\sqrt{3}/2\end{array}\right]\left[\begin{array}{c}{i}_{\mathrm{La}}\\ i_{\mathrm{Lb}}\\ i_{\mathrm{Lc}}\end{array}\right].$

According to claim 1 a kind of be applicable to distortion or uneven situation under three level active wave filter reference current detection methods, it is characterized in that, in step 3 by the voltage u of APF and electrical network points of common connection under α β coordinate _{s α}and u _{s β}through highly selective filter, carry out filtering, the fundametal compoment of the voltage of APF and electrical network points of common connection under acquisition α β coordinate with process be:

${\hat{X}}_{\mathrm{\α}}\left(s\right)=\frac{K(s+K)}{{(s+K)}^2+{\mathrm{\ω}}_c^2}{X}_{\mathrm{\α}}\left(s\right)-\frac{K{\mathrm{\ω}}_c}{{(s+K)}^2+{\mathrm{\ω}}_c^2}{X}_{\mathrm{\β}}\left(s\right)$

${\hat{X}}_{\mathrm{\β}}\left(s\right)=-\frac{K{\mathrm{\ω}}_c}{{(s+K)}^2+{\mathrm{\ω}}_c^2}{X}_{\mathrm{\α}}\left(s\right)+\frac{K(s+K)}{{(s+K)}^2+{\mathrm{\ω}}_c^2}{X}_{\mathrm{\β}}\left(s\right)$

Wherein, X is voltage, ω _c=2 π f _c, f _c=50Hz.

According to claim 1 a kind of be applicable to distortion or uneven situation under three level active wave filter reference current detection methods, it is characterized in that, in step 4 by the load current i of APF and electrical network points of common connection under α β coordinate _{l α}and i _{l β}through highly selective filter, carry out filtering, the fundametal compoment of the load current of APF and electrical network points of common connection under acquisition α β coordinate with process be:

${\hat{X}}_{\mathrm{\α}}\left(s\right)=\frac{K(s+K)}{{(s+K)}^2+{\mathrm{\ω}}_c^2}{X}_{\mathrm{\α}}\left(s\right)-\frac{K{\mathrm{\ω}}_c}{{(s+K)}^2+{\mathrm{\ω}}_c^2}{X}_{\mathrm{\β}}\left(s\right)$

${\hat{X}}_{\mathrm{\β}}\left(s\right)=-\frac{K{\mathrm{\ω}}_c}{{(s+K)}^2+{\mathrm{\ω}}_c^2}{X}_{\mathrm{\α}}\left(s\right)+\frac{K(s+K)}{{(s+K)}^2+{\mathrm{\ω}}_c^2}{X}_{\mathrm{\β}}\left(s\right)$

Wherein, X is electric current, ω _c=2 π f _c, f _c=50Hz.

6. a kind of three level active wave filter reference current detection methods in distortion or uneven situation that are applicable to according to claim 1, is characterized in that, the fundametal compoment of the voltage by APF under α β coordinate and electrical network points of common connection in step 6 with harmonic component i with load current _{h α}and i _{h β}, obtain instantaneous real power fluctuation part fluctuation part with instantaneous reactive power process be:

$\hat{p}={\hat{v}}_{\mathrm{\α}}{i}_{\mathrm{h\α}}+{\hat{v}}_{\mathrm{\β}}{i}_{\mathrm{h\β}}$

$\hat{q}={-\hat{v}}_{\mathrm{\β}}{i}_{\mathrm{h\α}}+{\hat{v}}_{\mathrm{\α}}{i}_{\mathrm{h\β}}.$

7. a kind of three level active wave filter reference current detection methods in distortion or uneven situation that are applicable to according to claim 1, is characterized in that, the fundametal compoment of the voltage by APF under α β coordinate and electrical network points of common connection in step 7 with fundametal compoment with load current with obtain the fundametal compoment of instantaneous reactive power process be:

$\hat{q}={-\hat{v}}_{\mathrm{\β}}{\hat{i}}_{\mathrm{\α}}+{\hat{v}}_{\mathrm{\α}}{\hat{i}}_{\mathrm{\β}}.$

According to claim 1 a kind of be applicable to distortion or uneven situation under three level active wave filter reference current detection methods, it is characterized in that the fundametal compoment of the voltage of APF and electrical network points of common connection under the variable of the variable of exporting by step 8 in step 10, step 9 output and α β coordinate with obtain the current reference value of APF under α β coordinate with process be:

$i_{\mathrm{\α}}^{*}=\frac{{\hat{v}}_{\mathrm{\α}}}{{\hat{v}}_{\mathrm{\α}}^2{\hat{v}}_{\mathrm{\β}}^2}(\hat{p}+p_c)-\frac{{\hat{v}}_{\mathrm{\β}}}{{\hat{v}}_{\mathrm{\α}}^2+{\hat{v}}_{\mathrm{\β}}^2}(\hat{q}+\stackrel{\‾}{q})$

$i_{\mathrm{\β}}^{*}=\frac{{\hat{v}}_{\mathrm{\β}}}{{\hat{v}}_{\mathrm{\α}}^2{\hat{v}}_{\mathrm{\β}}^2}(\hat{p}+p_c)+\frac{{\hat{v}}_{\mathrm{\α}}}{{\hat{v}}_{\mathrm{\α}}^2+{\hat{v}}_{\mathrm{\β}}^2}(\hat{q}+\stackrel{\‾}{q}).$

9. a kind of three level active wave filter reference current detection methods in distortion or uneven situation that are applicable to according to claim 1, is characterized in that, in step 11, step 10 are obtained to the current reference value of APF under α β coordinate with carry out two-phase and to the conversion of three-phase, obtain the A phase reference current of APF b phase reference current c phase reference current process be:

$\left[\begin{array}{c}{i}_a^{*}\\ i_b^{*}\\ i_c^{*}\end{array}\right]=\frac{2}{3}\left[\begin{array}{cc}1& 0\\ -1/2& \sqrt{3}/2\\ -1/2& -\sqrt{3}/2\end{array}\right]\left[\begin{array}{c}{i}_{\mathrm{\α}}^{*}\\ i_{\mathrm{\β}}^{*}\end{array}\right].$