阅读说明：本技术 一种应用于并网逆变器控制的dq旋转坐标系解耦方法 (DQ rotating coordinate system decoupling method applied to grid-connected inverter control ) 是由 马海红 于 2020-12-04 设计创作，主要内容包括：本发明适用于三相并网逆变器解耦技术领域,提供了一种应用于并网逆变器控制的DQ旋转坐标系解耦方法,所述直流组网的光储微网系统包括：获取并网逆变器的电感电压以及电感电流；根据所述电感电压以及所述电感电流建立所述电感电压的初始电压矩阵；对所述初始电压矩阵进行DQ旋转坐标系变换得到对应的目标电压矩阵；根据所述目标电压矩阵得到对应的耦合量；根据所述耦合量对DQ进行解耦。通过检测电感电压进行前馈,并基于电感电压实现DQ之间解耦,可以避免电气参数变化对控制性能的影响,进而有效避免电感感值变化对解耦带来的影响。提高DQ解耦的准确性以及解耦性能。(The invention is suitable for the technical field of decoupling of three-phase grid-connected inverters, and provides a DQ rotating coordinate system decoupling method applied to control of a grid-connected inverter, wherein the light storage micro-grid system of a direct-current networking comprises the following steps: obtaining the inductive voltage and the inductive current of the grid-connected inverter; establishing an initial voltage matrix of the inductive voltage according to the inductive voltage and the inductive current; carrying out DQ rotation coordinate system transformation on the initial voltage matrix to obtain a corresponding target voltage matrix; obtaining corresponding coupling quantity according to the target voltage matrix; and decoupling the DQs according to the coupling quantity. The feedforward is carried out by detecting the inductance voltage, the decoupling between DQs is realized based on the inductance voltage, the influence of the change of electrical parameters on the control performance can be avoided, and the influence of the change of inductance value on the decoupling is effectively avoided. The accuracy and the decoupling performance of DQ decoupling are improved.)

1. A DQ rotating coordinate system decoupling method applied to grid-connected inverter control is characterized by comprising the following steps:

obtaining the inductive voltage and the inductive current of the grid-connected inverter;

establishing an initial voltage matrix of the inductive voltage according to the inductive voltage and the inductive current;

carrying out DQ rotation coordinate system transformation on the initial voltage matrix to obtain a corresponding target voltage matrix;

obtaining corresponding coupling quantity according to the target voltage matrix;

and decoupling the DQs according to the coupling quantity.

2. The DQ rotating coordinate system decoupling method applied to grid-connected inverter control according to claim 1, wherein the step of obtaining an inductance voltage of the grid-connected inverter includes:

and detecting the inductive voltage of the grid-connected inverter through a voltage dividing resistor.

3. The DQ rotating coordinate system decoupling method applied to grid-connected inverter control according to claim 1, wherein the step of obtaining an inductance voltage of the grid-connected inverter includes:

and detecting the inductance voltage of the grid-connected inverter through a voltage transformer.

4. The DQ rotating coordinate system decoupling method applied to grid-connected inverter control according to claim 1, wherein the step of obtaining an inductance voltage of the grid-connected inverter includes:

and detecting the inductive voltage of the grid-connected inverter through a transformer.

5. The DQ rotating coordinate system decoupling method applied to grid-connected inverter control according to claim 1, wherein the step of obtaining an inductance voltage of the grid-connected inverter includes:

and detecting the voltages at two ends of the inductor, and performing difference processing to obtain the inductor voltage of the grid-connected inverter.

6. The DQ rotating coordinate system decoupling method applied to grid-connected inverter control according to claim 1, wherein the step of decoupling DQ according to the coupling amount comprises:

acquiring output D-axis voltage and inductance voltage D-axis voltage;

and controlling an output D axis and adding the voltage of the inductive voltage D axis.

7. The method for decoupling the DQ rotating coordinate system applied to grid-connected inverter control according to claim 2, wherein the step of decoupling the DQ according to the coupling amount further comprises:

acquiring output Q-axis voltage and inductance voltage Q-axis voltage;

the output Q-axis is controlled and the inductor voltage Q-axis voltage is added.

8. The DQ rotating coordinate system decoupling method as claimed in claim 1, wherein the grid-connected inverter is an LCL filter type inverter.

9. The DQ rotating coordinate system decoupling method as claimed in claim 7, wherein the LCL filter type inverter includes a first phase electric circuit, a second phase electric circuit, a third phase electric circuit;

the first phase electric circuit comprises a first phase inductor I, a first phase inductor II and a first phase capacitor, wherein the first phase inductor II is connected with the first phase inductor I in series, and one end of the first phase capacitor is arranged between the first phase inductor I and the first phase inductor II; one end of the first phase inductor II, which is far away from the first phase inductor I, outputs alternating current;

the second phase electric circuit comprises a first phase inductor, a second phase inductor and a second phase capacitor, wherein the second phase inductor is connected with the first phase inductor in series, and one end of the second phase capacitor is arranged between the first phase inductor and the second phase inductor; one end of the second phase inductor II, which is far away from the first phase inductor I, outputs alternating current;

the third-phase electric circuit comprises a first third-phase inductor, a second third-phase inductor and a third-phase capacitor, wherein the second third-phase inductor is connected with the first third-phase inductor in series, and one end of the third capacitor is arranged between the first third-phase inductor and the second third-phase inductor; one end of the second phase inductor, which is far away from the first phase inductor, outputs alternating current;

and the other end of the third-phase capacitor is respectively connected with the other ends of the second-phase capacitor and the first-phase capacitor.

Technical Field

The invention belongs to the technical field of decoupling of three-phase grid-connected inverters, and particularly relates to a DQ rotating coordinate system decoupling method applied to control of a grid-connected inverter.

Background

The control of a three-phase grid-connected inverter generally involves DQ conversion. In the resulting expression transformed from the ABC coordinate system to the DQ rotation coordinate system, there is an electrical quantity coupling between the DQs. These couplings have a significant impact on control performance and ultimately on device performance. To achieve better control performance, the DQs are typically decoupled. When the inductive current DQ is decoupled in a coupling mode, a coupling value is calculated according to the inductive current, the inductive value and the frequency, and then the coupling value acts on control feedforward.

However, the inductance in the power electronics is not a constant value, but decays as the inductor current increases. These factors cause inaccuracies in the calculated coupling values during the decoupling of the DQs, which in turn has an impact on control performance. It can be seen that the existing inverter decoupling method has the problems of low decoupling accuracy and poor performance

Disclosure of Invention

The embodiment of the invention provides a DQ rotating coordinate system decoupling method applied to grid-connected inverter control, and aims to solve the problems of low decoupling accuracy and poor performance of the existing inverter decoupling method.

The embodiment of the invention provides a DQ rotating coordinate system decoupling method applied to grid-connected inverter control, which comprises the following steps:

obtaining the inductive voltage and the inductive current of the grid-connected inverter;

establishing an initial voltage matrix of the inductive voltage according to the inductive voltage and the inductive current;

carrying out DQ rotation coordinate system transformation on the initial voltage matrix to obtain a corresponding target voltage matrix;

obtaining corresponding coupling quantity according to the target voltage matrix;

and decoupling the DQs according to the coupling quantity.

Further, the step of obtaining the inductance voltage of the grid-connected inverter comprises:

detecting the inductive voltage of the grid-connected inverter through a voltage dividing resistor;

further, the step of obtaining the inductance voltage of the grid-connected inverter comprises:

detecting the inductance voltage of the grid-connected inverter through a voltage transformer;

further, the step of obtaining the inductance voltage of the grid-connected inverter comprises:

and detecting the inductive voltage of the grid-connected inverter through a transformer.

Further, the step of obtaining the inductance voltage of the grid-connected inverter comprises:

and detecting the voltages at two ends of the inductor, and performing difference processing to obtain the inductor voltage of the grid-connected inverter.

Still further, the step of decoupling the DQs based on the amount of coupling comprises:

acquiring output D-axis voltage and inductance voltage D-axis voltage;

and controlling an output D axis and adding the voltage of the inductive voltage D axis.

Still further, the step of decoupling the DQs based on the amount of coupling further comprises:

acquiring output Q-axis voltage and inductance voltage Q-axis voltage;

the output Q-axis is controlled and the inductor voltage Q-axis voltage is added.

Further, the grid-connected inverter is an LCL filter type inverter.

Further, the LCL filter type inverter includes a first phase electrical circuit, a second phase electrical circuit, a third phase electrical circuit;

the first phase electric circuit comprises a first phase inductor I, a first phase inductor II and a first phase capacitor, wherein the first phase inductor II is connected with the first phase inductor I in series, and one end of the first phase capacitor is arranged between the first phase inductor I and the first phase inductor II; one end of the first phase inductor II, which is far away from the first phase inductor I, outputs alternating current;

the second phase electric circuit comprises a first phase inductor, a second phase inductor and a second phase capacitor, wherein the second phase inductor is connected with the first phase inductor in series, and one end of the second phase capacitor is arranged between the first phase inductor and the second phase inductor; one end of the second phase inductor II, which is far away from the first phase inductor I, outputs alternating current;

the third-phase electric circuit comprises a first third-phase inductor, a second third-phase inductor and a third-phase capacitor, wherein the second third-phase inductor is connected with the first third-phase inductor in series, and one end of the third capacitor is arranged between the first third-phase inductor and the second third-phase inductor; one end of the second phase inductor, which is far away from the first phase inductor, outputs alternating current;

and the other end of the third-phase capacitor is respectively connected with the other ends of the second-phase capacitor and the first-phase capacitor.

The invention achieves the following beneficial effects: obtaining the inductive voltage and the inductive current of the grid-connected inverter; establishing an initial voltage matrix of the inductive voltage according to the inductive voltage and the inductive current; carrying out DQ rotation coordinate system transformation on the initial voltage matrix to obtain a corresponding target voltage matrix; obtaining corresponding coupling quantity according to the target voltage matrix; and decoupling the DQs according to the coupling quantity. The feedforward is carried out by detecting the inductance voltage, the decoupling between DQs is realized based on the inductance voltage, the influence of the change of electrical parameters on the control performance can be avoided, and the influence of the change of inductance value on the decoupling is effectively avoided. The accuracy and the decoupling performance of DQ decoupling are improved.

Drawings

Fig. 1 is a flowchart of a DQ rotating coordinate system decoupling method applied to grid-connected inverter control according to an embodiment of the present invention;

fig. 2 is a circuit diagram of a grid-connected inverter according to an embodiment of the present invention.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is described in further detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

According to the invention, the feedforward is carried out by detecting the inductance voltage, and the decoupling between DQs is realized based on the inductance voltage, so that the influence of the change of the electrical parameters on the control performance can be avoided, and the influence of the change of the inductance value on the decoupling can be effectively avoided. The accuracy and the decoupling performance of DQ decoupling are improved.

As shown in fig. 1, fig. 1 is a flowchart of a DQ rotating coordinate system decoupling method applied to grid-connected inverter control according to an embodiment of the present invention. The DQ rotating coordinate system decoupling method applied to grid-connected inverter control comprises the following steps:

and 101, acquiring the inductive voltage and the inductive current of the grid-connected inverter.

The inductor voltage is the voltage of an inductor in the inverter. The inductor voltage includes the voltage of the inductor of the inverter three-phase power. The detection mode of the inductor voltage is not specifically formulated, and a direct mode can be used, including but not limited to detection modes of a divider resistor, a voltage transformer, a transformer and the like. Of course, the detection mode of the inductor voltage may also use an indirect mode, for example, the inductor voltage may be obtained by detecting the voltages at the two ends of the inductor and then performing difference processing.

The inductor current is the current of an inductor in the inverter, and specifically is the current of an inductor for three-phase power in the inverter. Of course, the detection mode of the inductor voltage is not specifically established, and a direct mode may be used, and of course, an indirect mode may also be used.

In an embodiment of the present invention, as shown in fig. 2, fig. 2 is a circuit diagram of a grid-connected inverter according to an embodiment of the present invention. The grid-connected inverter is an LCL filter type inverter. The LCL filter type inverter comprises a first phase electric circuit, a second phase electric circuit and a third phase electric circuit; the first phase electric circuit comprises a first phase inductor I, a first phase inductor II and a first phase capacitor, wherein the first phase inductor II is connected with the first phase inductor I in series, and one end of the first phase capacitor is arranged between the first phase inductor I and the first phase inductor II; one end of the first phase inductor II, which is far away from the first phase inductor I, outputs alternating current; the second phase electric circuit comprises a first second phase inductor, a second phase inductor and a second phase capacitor, wherein the second phase inductor is connected with the first second phase inductor in series, and one end of the second phase capacitor is arranged between the first second phase inductor and the second phase inductor; one end of the second phase inductor II, which is far away from the first phase inductor I, outputs alternating current; the third phase electric circuit comprises a first third phase inductor, a second third phase inductor and a third phase capacitor, wherein the second third phase inductor is connected with the first third phase inductor in series, and one end of the third phase capacitor is arranged between the first third phase inductor and the second third phase inductor; one end of the second phase inductor, which is far away from the first phase inductor, outputs alternating current; the other end of the third phase capacitor is connected with the other ends of the second phase capacitor and the first phase capacitor respectively.

It should be noted that the first phase circuit may be represented by phase a, the second phase circuit may be represented by phase B, and the third phase circuit may be represented by phase C. The inductor voltage comprises the voltage of the phase A inductor, the voltage of the phase B inductor and the voltage of the phase C inductor. The inductor current may include the current of the phase a inductor, the current of the phase B inductor, and the current of the phase C inductor.

Specifically, according to different detection modes of the inductor voltage, step 102 may include: and detecting the inductance voltage of the grid-connected inverter through the voltage dividing resistor. Step 102 may also include: and detecting the inductance voltage of the grid-connected inverter through a voltage transformer. Step 102 may also include: and detecting the inductive voltage of the grid-connected inverter through the transformer. Step 102 may also include: and detecting the voltages at two ends of the inductor, and performing difference processing to obtain the inductor voltage of the grid-connected inverter.

And 102, establishing an initial voltage matrix of the inductive voltage according to the inductive voltage and the inductive current.

Specifically, the inductance-inductance voltages and inductance currents of the a-phase, the B-phase, and the C-phase in the grid-connected inverter are taken as an example, and the initial voltage matrix may be expressed as:

wherein, V_1a(t) is the A-phase inductance voltage, V_1b(t) is the B-phase inductance voltage, V_1c(t) is C-phase inductance voltage, i_1a(t) is an A-phase inductive current, i_1b(t) is B-phase inductive current, i_1c(t) is a C-phase inductive current, t is time, d/dt [ [ alpha ] ]]And (4) derivation, namely derivation of the inductor current.

Of course, when the grid-connected inverter includes multiple phases, the initial voltage matrix is established in the same manner, that is, the initial voltage matrix is also transformed correspondingly.

And 103, carrying out DQ rotation coordinate system transformation on the initial voltage matrix to obtain a corresponding target voltage matrix.

The DQ rotating coordinate system is converted from three-phase alternating current to two direct current quantities of D and Q, and control is convenient. For the grid-connected inverter, if the phase locking is accurate, V is obtained after the voltage of the power grid is converted_d＝W_m，V_q＝0，V_mIs the grid phase voltage amplitude; the grid current id is the active current, and iq is the reactive current.

Specifically, after the initial voltage matrix is obtained, the initial voltage matrix is subjected to DQ rotation coordinate system transformation to finally obtain a corresponding target voltage matrix.

The target voltage matrix may be expressed as:

and 104, obtaining corresponding coupling quantity according to the target voltage matrix.

Specifically, after the target voltage matrix is obtained, since the change of the component of the inductive current DQ is small in the process of controlling the steady state, that is, the first phase on the right of the equation is equal to 0, the corresponding coupling amount is also obtained, and the target voltage matrix is obtained and transformed into:

so- ω L₁i_1q(t) and ω L₁i_1d(t) are each equal to the value of DQ of the inductor voltage, thereby showing that there is no longer coupling between DQ.

And 105, decoupling the DQ according to the coupling quantity.

Specifically, after the required coupling amount is determined, the interface performs DQ decoupling according to the coupling amount.

More specifically, step 105 further comprises the steps of: acquiring output D-axis voltage and inductance voltage D-axis voltage; the control outputs the D-axis and adds the inductor voltage D-axis voltage.

Step 105 further comprises the steps of: acquiring output Q-axis voltage and inductance voltage Q-axis voltage; the output Q-axis is controlled and the inductor voltage Q-axis voltage is added.

The following formula is obtained based on formula 3 according to step 105:

furthermore, the inductance voltage D-axis voltage and the inductance voltage Q-axis voltage can be decoupled, and the influence of the change of the electrical parameters on the control performance can be avoided.

In the embodiment of the invention, the inductive voltage and the inductive current of the grid-connected inverter are obtained; establishing an initial voltage matrix of the inductive voltage according to the inductive voltage and the inductive current; carrying out DQ rotation coordinate system transformation on the initial voltage matrix to obtain a corresponding target voltage matrix; obtaining corresponding coupling quantity according to the target voltage matrix; and decoupling the DQs according to the coupling quantity. The feedforward is carried out by detecting the inductance voltage, the decoupling between DQs is realized based on the inductance voltage, the influence of the change of electrical parameters on the control performance can be avoided, and the influence of the change of inductance value on the decoupling is effectively avoided. The accuracy and the decoupling performance of DQ decoupling are improved.

The present invention is not limited to the above preferred embodiments, and any modifications, equivalent substitutions and improvements made within the spirit and principle of the present invention should be included in the protection scope of the present invention.