CN104092237B - A kind of 3-phase power converter grid-connected current division decoupling control method - Google Patents

Abstract

The invention discloses a kind of 3-phase power converter grid-connected current division decoupling control method, step one, to the three-phase grid current sample of current transformer, and utilize synchronized angle θ to its carry out Park conversion obtain d axle component i _dwith q axle component i _q; Step 2, to given value of current amount with respectively with i _dand i _qrelatively, error signal i is obtained _{d_err}and i _{q_err}, and according to given value of current amount variable quantity given value of current amount variable quantity i _{d_err}and i _{q_err}decoupling zero splitting factor k is obtained by fuzzy algorithmic approach; Step 3, uses electric current specified rate with be multiplied with decoupling zero splitting factor k respectively and obtain first group of current split decoupling zero component; Step 4, uses i _dand i _qdivide complementary factor 1-k to be respectively multiplied to obtain second group of current split decoupling zero component with decoupling zero; Step 5, is added with second group of current split decoupling zero component the Current Decoupling amount i obtaining control system by first group of current split decoupling zero component _{d_F}and i _{q_F}, carry out electric current full decoupling control.The invention solves that existing decoupling control method is steady, the conflicting problem of dynamic property.

Description

A kind of 3-phase power converter grid-connected current division decoupling control method

Technical field

The present invention relates to a kind of 3-phase power converter grid-connected current division decoupling control method, belong to 3-phase power converter control field.

Background technology

In recent years, 3-phase power converter is as the jockey of new forms of energy and electrical network, and utilization more and more extensive, simultaneously along with the variation of application scenario, it is also proposed higher requirement to steady, the dynamic property of its 3-phase power converter.

3-phase power converter main circuit and control block diagram as shown in Figure 1, generally include and to be connected with electrical network for the low pass filter L (or LC, LCL filter) of the grid-connected harmonic current of filtering, current-voltage sampling circuit, the three phase full bridge circuit be made up of power switch pipe and controller.At present, in order to realize better controlling fundamental signal, generally to take three-phase voltage under rest frame and electric current by synchronous rotating angle under dq two-phase synchronous rotating frame.After carrying out rotating coordinate transformation, the electric current between system d, q axle also exists coupling, and namely d (q) axle controlled quentity controlled variable can have an impact to q (d) axle controlled quentity controlled variable.Therefore in order to carry out independent control to d, q electric current, need to carry out decoupling zero process to system.Traditional decoupling method realizes uneoupled control by being added on q axle and d axis controller after the d axle of electric current and q axle component are multiplied by filtering induction reactance respectively, therefore, when given value of current amount is suddenlyd change, d, q axle reference voltage of 3-phase power converter directly cannot reflect the change of grid-connected current, thus namely dynamic property is undesirable slowly to cause system responses.In addition be only considered first-harmonic amount owing to carrying out rotating coordinate transformation, if therefore there is background harmonics in electrical network, thus can current harmonics be there is, and now current decoupled control amount can not reflect the time of day of system, d axle and q decoupler shaft component influence each other further, finally cause the reduction of grid-connected current waveform quality and steady-state behaviour to be deteriorated.

For these reasons, be therefore necessary the current decoupling control method designing a kind of 3-phase power converter, solve that existing decoupling control method is steady, the conflicting problem of dynamic property, improve dynamic response performance and the steady-state current quality of 3-phase power converter.

Summary of the invention

The invention provides a kind of 3-phase power converter grid-connected current division decoupling control method, solve that existing decoupling control method is steady, the conflicting problem of dynamic property, improve dynamic response performance and the steady-state current quality of 3-phase power converter.

In order to solve the problems of the technologies described above, the technical solution adopted in the present invention is:

A kind of 3-phase power converter grid-connected current division decoupling control method, comprises the following steps,

Step one, to the three-phase grid current sample of current transformer, and utilize synchronized angle θ to its carry out Park conversion obtain d axle component i _dwith q axle component i _q;

Step 2, to given value of current amount with the i obtained with step one respectively _dand i _qrelatively, error signal i is obtained _{d_err}and i _{q_err}, and according to given value of current amount variable quantity given value of current amount variable quantity i _{d_err}and i _{q_err}decoupling zero splitting factor k is obtained by fuzzy algorithmic approach;

Step 3, uses electric current specified rate with the decoupling zero splitting factor k obtained with step 2 is respectively multiplied and obtains first group of current split decoupling zero component;

Step 4, the i obtained by step one _dand i _qdivide complementary factor 1-k to be respectively multiplied to obtain second group of current split decoupling zero component with decoupling zero;

Step 5, second group of current split decoupling zero component that the first group of current split decoupling zero component and the step 4 that step 3 are obtained obtain is added the Current Decoupling amount i obtaining control system _{d_F}and i _{q_F}, carry out electric current full decoupling control.

In step one, Park transformation for mula is as follows,

$\left[\begin{array}{c}{i}_d\\ i_q\end{array}\right]=\left[\begin{array}{ccc}\cos \left(\mathrm{\θ}\right)& \cos (\mathrm{\θ}-\frac{2\mathrm{\π}}{3})& \cos (\mathrm{\θ}+\frac{2\mathrm{\π}}{3})\\ -\sin \left(\mathrm{\θ}\right)& -\sin (\mathrm{\θ}-\frac{2\mathrm{\π}}{3})& -\sin (\mathrm{\θ}+\frac{2\mathrm{\π}}{3})\end{array}\right]\left[\begin{array}{c}{i}_a\\ i_b\\ i_c\end{array}\right]---\left(1\right)$

Wherein, i _a, i _b, i _cfor three-phase grid sample rate current.

Basis in step 2 i _{d_err}and i _{q_err}the process being obtained decoupling zero splitting factor k by fuzzy algorithmic approach is, with i _{d_err}and i _{q_err}for the input of fuzzy controller, after successively obfuscation, fuzzy reasoning and sharpening are carried out to it, obtain the output k of fuzzy controller; i _{d_err}and i _{q_err}fuzzy set all get 5, the fuzzy set of k gets 3.

Current Decoupling amount i in step 5 _{d_F}and i _{q_F}computing formula be,

$\left[\begin{array}{c}{i}_{d\_F}\\ i_{q\_F}\end{array}\right]=k\left[\begin{array}{c}{i}_d^{*}\\ i_q^{*}\end{array}\right]+(1-k)\left[\begin{array}{c}{i}_d\\ i_q\end{array}\right]---\left(2\right).$

The invention has the beneficial effects as follows: the present invention is ensureing, under the prerequisite that current transformer overshoot is enough little, effectively to improve the response speed of current transformer; Simultaneously when line voltage has powerful connections harmonic wave, also effectively can suppress the extra grid-connected current harmonic wave introduced due to decoupling controller.

Accompanying drawing explanation

Fig. 1 is 3-phase power converter main circuit diagram and Traditional control block diagram.

Fig. 2 is 3-phase power converter grid-connected current of the present invention division uneoupled control schematic diagram.

Fig. 3 is flow chart of the present invention.

Fig. 4 is the relation that decoupling zero splitting factor k of the present invention and current step respond.

Fig. 5 is that decoupling zero splitting factor k of the present invention is on the impact of grid-connected current THD.

Embodiment

Below in conjunction with Figure of description, the invention will be further described.Following examples only for technical scheme of the present invention is clearly described, and can not limit the scope of the invention with this.

As shown in Figure 2, be 3-phase power converter grid-connected current division uneoupled control schematic diagram of the present invention.Electric current loop decoupling zero amount is added by first, second group current split decoupling zero component and obtains, and specific implementation comprises the following steps as shown in Figure 3.

Step one, to the three-phase grid current sample of current transformer, and utilize synchronized angle θ to its carry out Park conversion obtain d axle component i _dwith q axle component i _q.

Park transformation for mula is as follows,

$\left[\begin{array}{c}{i}_d\\ i_q\end{array}\right]=\left[\begin{array}{ccc}\cos \left(\mathrm{\θ}\right)& \cos (\mathrm{\θ}-\frac{2\mathrm{\π}}{3})& \cos (\mathrm{\θ}+\frac{2\mathrm{\π}}{3})\\ -\sin \left(\mathrm{\θ}\right)& -\sin (\mathrm{\θ}-\frac{2\mathrm{\π}}{3})& -\sin (\mathrm{\θ}+\frac{2\mathrm{\π}}{3})\end{array}\right]\left[\begin{array}{c}{i}_a\\ i_b\\ i_c\end{array}\right]---\left(1\right)$

Wherein, i _a, i _b, i _cfor three-phase grid sample rate current.

Step 2, to given value of current amount with the i obtained with step one respectively _dand i _qrelatively, error signal i is obtained _{d_err}and i _{q_err}, and according to given value of current amount variable quantity given value of current amount variable quantity i _{d_err}and i _{q_err}decoupling zero splitting factor k is obtained by fuzzy algorithmic approach.

Above-mentioned fuzzy algorithmic approach with i _{d_err}and i _{q_err}for the input of fuzzy controller, obtain the output k of fuzzy controller to it after carrying out obfuscation, fuzzy reasoning and sharpening successively, its process is that prior art is not here described in detail, wherein i _{d_err}and i _{q_err}fuzzy set all get 5, the fuzzy set of k gets 5, and be expressed as { NB=is negative large, and during NM=is negative, ZE=zero, PM=hits exactly, and PB=is honest }, the fuzzy rule asking for concrete employing of its k value is as shown in table 1 below.

Table 1 fuzzy rule

Step 3, uses electric current specified rate with the decoupling zero splitting factor k obtained with step 2 is respectively multiplied and obtains first group of current split decoupling zero component.

Step 4, the i obtained by step one _dand i _qdivide complementary factor 1-k to be respectively multiplied to obtain second group of current split decoupling zero component with decoupling zero.

Step 5, second group of current split decoupling zero component that the first group of current split decoupling zero component and the step 4 that step 3 are obtained obtain is added the Current Decoupling amount i obtaining control system _{d_F}and i _{q_F}, carry out electric current full decoupling control, Current Decoupling amount i _{d_F}and i _{q_F}computing formula be,

$\left[\begin{array}{c}{i}_{d\_F}\\ i_{q\_F}\end{array}\right]=k\left[\begin{array}{c}{i}_d^{*}\\ i_q^{*}\end{array}\right]+(1-k)\left[\begin{array}{c}{i}_d\\ i_q\end{array}\right]---\left(2\right).$

As shown in Figure 3, be relation that decoupling zero splitting factor k of the present invention and current step respond.Control principle drawing according to Fig. 2 builds simulation model, when the step saltus step of d axle specified rate, response speed corresponding when getting different decoupling zero splitting factor k, can find out that the larger response of k is more opened, but simultaneously overshoot is also larger, and overshoot is crossed conference and is caused current transformer overcurrent, when k gets 0.5, when ensure that response speed, also effectively inhibit system power overshoot.

Fig. 5 is that decoupling zero splitting factor k of the present invention is on the impact of grid-connected current THD.Control principle drawing according to Fig. 2 builds simulation model, add 7,11 background harmonics situations in line voltage under, when getting different decoupling zero splitting factor k, the THD that grid-connected current is corresponding, k value is larger, and the THD of grid-connected current is less, when k gets 1, THD obtains best control effects.

In sum, take 3-phase power converter grid-connected current of the present invention to divide decoupling control method, ensureing, under the prerequisite that current transformer overshoot is enough little, effectively to improve the response speed of current transformer; Simultaneously when line voltage has powerful connections harmonic wave, also effectively can suppress the extra grid-connected current harmonic wave introduced due to decoupling controller.

More than show and describe general principle of the present invention, principal character and advantage.The technical staff of the industry should understand; the present invention is not restricted to the described embodiments; what describe in above-described embodiment and specification just illustrates principle of the present invention; without departing from the spirit and scope of the present invention; the present invention also has various changes and modifications, and these changes and improvements all fall in the claimed scope of the invention.Application claims protection range is defined by appending claims and equivalent thereof.

Claims (4)

1. a 3-phase power converter grid-connected current division decoupling control method, is characterized in that: comprise the following steps,

Step one, to the three-phase grid current sample of current transformer, and utilize synchronized angle θ to its carry out Park conversion obtain d axle component i _dwith q axle component i _q;

Step 2, to given value of current amount with the i obtained with step one respectively _dand i _qrelatively, error signal i is obtained _{d_err}and i _{q_err}, and according to given value of current amount variable quantity given value of current amount variable quantity i _{d_err}and i _{q_err}decoupling zero splitting factor k is obtained by fuzzy algorithmic approach;

Step 3, uses electric current specified rate with the decoupling zero splitting factor k obtained with step 2 is respectively multiplied and obtains first group of current split decoupling zero component;

Step 4, the i obtained by step one _dand i _qdivide complementary factor 1-k to be respectively multiplied to obtain second group of current split decoupling zero component with decoupling zero;

Step 5, second group of current split decoupling zero component that the first group of current split decoupling zero component and the step 4 that step 3 are obtained obtain is added the Current Decoupling amount i obtaining control system _{d_F}and i _{q_F}, carry out electric current full decoupling control;

Current Decoupling amount i _{d_F}and i _{q_F}computing formula be,

$\left[\begin{array}{c}{i}_{d\_F}\\ i_{q\_F}\end{array}\right]=k\left[\begin{array}{c}{i}_d^{*}\\ i_q^{*}\end{array}\right]+(1-k)\left[\begin{array}{c}{i}_d\\ i_q\end{array}\right]---\left(2\right).$

2. a kind of 3-phase power converter grid-connected current division decoupling control method according to claim 1, is characterized in that: in step one, Park transformation for mula is as follows,

$\left[\begin{array}{c}{i}_d\\ i_q\end{array}\right]=\left[\begin{array}{ccc}\cos \left(\mathrm{\θ}\right)& \cos (\mathrm{\θ}-\frac{2\mathrm{\π}}{3})& \cos (\mathrm{\θ}+\frac{2\mathrm{\π}}{3})\\ -\sin \left(\mathrm{\θ}\right)& -\sin (\mathrm{\θ}-\frac{2\mathrm{\π}}{3})& -\sin (\mathrm{\θ}+\frac{2\mathrm{\π}}{3})\end{array}\right]\left[\begin{array}{c}{i}_a\\ i_b\\ i_c\end{array}\right]---\left(1\right)$

Wherein, i _a, i _b, i _cfor three-phase grid sample rate current.

3. a kind of 3-phase power converter grid-connected current division decoupling control method according to claim 1, is characterized in that: basis in step 2 i _{d_err}and i _{q_err}the process being obtained decoupling zero splitting factor k by fuzzy algorithmic approach is, with i _{d_err}and i _{q_err}for the input of fuzzy controller, after successively obfuscation, fuzzy reasoning and sharpening are carried out to it, obtain the output k of fuzzy controller.

4. a kind of 3-phase power converter grid-connected current division decoupling control method according to claim 3, is characterized in that: i _{d_err}and i _{q_err}fuzzy set all get 5, the fuzzy set of k gets 3.