Three-phase inverter current direct-current component decoupling control system and method
By adopting a three-phase inverter current DC component decoupling control system in a three-phase inverter, the problem of poor current DC component control effect in the prior art is solved, and effective decoupling of current DC component and improving grid safety are achieved.
Patent Information
- Application Number
- CN202510002575.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-01-02
- Publication Date
- 2025-05-09
AI Technical Summary
The current DC component control effect of existing three-phase inverters is poor in grid connection, resulting in increased transformer losses, seriously affecting the safety of the power grid.
A three-phase inverter current DC component decoupling control system is adopted, including a DC component sampling module, a DC component control module and a system control module. By collecting the three-phase inverter current, calculating its DC component, controlling the DC component of each phase, forming a three-phase DC component control quantity, and acting on the three-phase inverter current control loop, realizing the decoupling of the DC component of the current.
It effectively eliminates the DC component of the three-phase inverter current, improves control accuracy, reduces transformer losses, and ensures the safety of the power grid.
Smart Images
Figure CN119965951A_ABST
Abstract
Description
Technical Field
[0001] The invention relates to the field of power supply, and in particular to decoupling of a direct current component of a three-phase inverter connected to a grid. Background Art
[0002] In the field of three-phase inverter grid connection, for economic considerations, more and more products use the method of injecting output current directly into the grid without isolation transformer. If the DC component of the current injected into the grid is too large, it will cause transformer loss to increase or even saturate, seriously affecting the safety of the grid. The national grid connection regulations stipulate that the DC component fed to the grid should not exceed 0.5% of its output current rating.
[0003] In the existing three-phase three-wire inverter grid-connected current DC component control method, most of them adopt the scheme of separately controlling the DC component of the three-phase inverter current. Since the three-phase currents affect each other, controlling any one phase will affect the size of the other two phases. Therefore, the scheme of separately controlling the three phases cannot achieve the ideal control effect. For this reason, in the prior art, a decoupler is generally loaded in the three-phase inverter to eliminate the mutual interference of the three-phase control. However, the decoupling effect of the existing decoupler is poor and the decoupling calculation is too complicated.
[0004] Therefore, there is an urgent need for a three-phase inverter current DC component decoupling control that can solve the above-mentioned problem. Summary of the invention
[0005] The object of the present invention is to provide a three-phase inverter current DC component decoupling control system and method, which can quickly and effectively eliminate the three-phase inverter current DC component.
[0006] In order to achieve the above object, the present invention provides a three-phase inverter current DC component decoupling control system, comprising: a DC component sampling module, collecting the three-phase inverter current to obtain the three-phase inverter current DC component, the three-phase inverter current DC component includes the first phase current DC component I dca , the DC component of the second phase current I dcb and the third phase current DC component I dcc ; A DC component control module, respectively, the first phase current DC component I dca and the DC component of the second phase current I dcb Control is performed to obtain the first phase DC component control quantity U dca_ctl and the second phase DC component control quantity U dcb_ctl , according to U dcc_ctl =-U dca_ctl -U dcb_ctl Get the third phase DC component control quantity U dcc_ctl , the first phase DC component control quantity U dca_ctl , the second phase DC component control quantity U dcb_ctland the third phase DC component control quantity U dcc_ctl A three-phase DC component control quantity is formed; a system control module applies the three-phase DC component control quantity to a three-phase inverter current control loop to achieve decoupling control of the DC component of the three-phase inverter current.
[0007] Preferably, the DC component sampling module collects the inverter inductor current in T cycles, and calculates the average value of the inverter inductor current in T cycles to obtain the three-phase inverter current DC component, where T is 1 or an integer greater than or equal to 2. For example, T can be equal to 5. Different from the prior art that uses hardware to filter out the inverter current AC quantity and retains the DC quantity to obtain the inverter DC component, this solution calculates the average value of the inverter current sampling as the inverter current DC component, and can select low-cost Hall devices, while removing the hardware filtering circuit to reduce costs.
[0008] Preferably, the DC component control module sets the DC component of the first phase to 0, and sets the DC component of the first phase inverter current on the AC side to dca As feedback, the error value of the first phase is obtained, and the error value of the first phase is subjected to PI control to obtain the first phase DC component control quantity U dca_ctl The DC component control module sets the DC component of the second phase to 0, and sets the DC component of the second phase inverter current on the AC side to i dcb As feedback, the error value of the second phase is obtained, and the error value of the second phase is subjected to PI control to obtain the second phase DC component control quantity U dcb_ctl This scheme directly sets the given value of the DC component to 0, and then obtains the error value based on the DC component of the inverter current on the AC side as feedback, which is used as the corresponding DC component control quantity, and is easy to calculate.
[0009] Preferably, the system control module applies the three-phase DC component control amount to the three-phase inverter current control loop to obtain a three-phase inverter control output signal, and transmits the three-phase inverter control output signal to the PWM signal generator of the three-phase inverter, thereby realizing the control of the DC component of the three-phase inverter current. The present invention obtains the three-phase inverter control output signal through the three-phase inverter current control loop, and then converts the three-phase DC component control amount to the transmission device PWM signal generator to eliminate the DC component of the three-phase inverter current.
[0010] Specifically, the system control module superimposes the three-phase DC component control quantity and the inverter current setting of the corresponding phase as a new inverter current setting, subtracts the inverter current sampling of the corresponding phase from the new inverter current setting to obtain the three-phase inverter control loop error value, and the three-phase inverter control loop error value is independently subjected to PI control and repeated control to obtain the three-phase inverter control output signal. The three-phase inverter current control loop obtains the three-phase inverter control output signal through independent three-phase control to prevent mutual interference between the three phases, and the three-phase inverter control output signal obtained through PI control and repeated control can better eliminate the DC component of the three-phase inverter current.
[0011] Specifically, the system control module obtains the three-phase voltage control value through dq control, and superimposes the three-phase voltage control value with the three-phase DC component control amount as the three-phase inverter control output signal. The three-phase inverter current control loop of this solution adopts dq control, and directly superimposes the three-phase voltage control value on the three-phase inverter modulation wave (three-phase voltage control value), thereby realizing the three-phase inverter current DC component control.
[0012] Of course, the three-phase inverter current control loop of the present invention is not limited to the above two types, and the three-phase inverter current control can be performed according to other control methods. It only needs to positively superimpose the three-phase DC component control amount on the parameters of the three-phase inverter current control and adjust the three-phase inverter current control parameters to achieve decoupling of the DC component of the three-phase inverter current and effectively eliminate the three-phase inverter current control.
[0013] More specifically, the system control module obtains the three-phase voltage control value through dq control as follows: the system control module subtracts the q-axis component and d-axis component of the inverter current sampled from the given q-axis component and d-axis component of the three-phase inverter current, respectively, and performs PI control and limiting processing on them, and then superimposes them with the q-axis component and d-axis component of the inverter voltage and transmits them to the dq / adc conversion unit to convert them into a three-phase voltage control value.
[0014] The present invention also provides a three-phase inverter current DC component decoupling control method, comprising: collecting the three-phase inverter current to obtain the three-phase inverter current DC component, wherein the three-phase inverter current DC component includes the first phase current DC component I dca , the DC component of the second phase current I dcb and the third phase current DC component I dcc ; respectively, the first phase current DC component I dca and the second phase current DC component I dcb Control is performed to obtain the first phase DC component control quantity U dca_ctl and the second phase DC component control quantity U dcb_ctl ; Based on U dcc_ctl =-U dca_ctl -Udcb_ctl Get the third phase DC component control quantity U dcc_ctl The first phase DC component control quantity U dca_ctl , the second phase DC component control quantity U dcb_ctl and the third phase DC component control quantity U dcc_ctl A three-phase DC component control quantity is formed; the three-phase DC component control quantity is applied to a three-phase inverter current control loop to achieve decoupling control of the DC component of the three-phase inverter current.
[0015] Preferably, collecting the three-phase inverter current to obtain the three-phase inverter current DC component specifically includes: collecting the inverter inductor current in T cycles, and calculating the average value of the inverter inductor current in T cycles to obtain the three-phase inverter current DC component, where T is 1 or an integer greater than or equal to 2. Different from the prior art that uses hardware to filter out the inverter current AC quantity and retains the DC quantity to obtain the inverter DC component, this solution calculates the average value of the inverter current sampling as the inverter current DC component, and can select low-cost Hall devices, while removing the hardware filtering circuit to reduce costs.
[0016] Preferably, the first phase current DC component I dca and the second phase current DC component I dcb Control is performed to obtain the first phase DC component control quantity U dca_ctl and the second phase DC component control quantity U dcb_ctl Specifically, the first phase inverter current DC component i on the AC side is converted into dca As feedback, the error value of the first phase is obtained, and the error value of the first phase is subjected to PI control to obtain the first phase DC component control quantity U dca_ctl ; Set the DC component of the second phase to 0, and set the DC component of the second phase inverter current on the AC side to dcb As feedback, the error value of the second phase is obtained, and the error value of the second phase is subjected to PI control to obtain the second phase DC component control quantity U dcb_ctl This scheme directly sets the given value of the DC component to 0, and then obtains the error value based on the DC component of the inverter current on the AC side as feedback, which is used as the corresponding DC component control quantity, and is easy to calculate.
[0017] Preferably, applying the three-phase DC component control amount to the three-phase inverter current control loop specifically includes: applying the three-phase DC component control amount to the three-phase inverter control output signal of the three-phase inverter current control loop, and obtaining and transmitting the three-phase inverter control output signal to the PWM signal generator of the three-phase inverter, thereby achieving control of the DC component of the three-phase inverter current. The present invention obtains the three-phase inverter control output signal through the three-phase inverter current control loop, and then converts the three-phase DC component control amount to the transmission device PWM signal generator to eliminate the DC component of the three-phase inverter current.
[0018] Specifically, applying the three-phase DC component control quantity to the three-phase inverter control output signal of the three-phase inverter current control loop specifically includes: superimposing the three-phase DC component control quantity and the inverter current given of the corresponding phase as a new inverter current given, subtracting the inverter current sampling of the corresponding phase from the new inverter current given to obtain three-phase inverter control loop error values respectively, and independently subjecting the three-phase inverter control loop error values to PI control and repeated control to obtain the three-phase inverter control output signal. The three-phase inverter current control loop obtains the three-phase inverter control output signal through independent three-phase control to prevent mutual interference between the three phases, and through PI control and repeated control, the obtained three-phase inverter control output signal has a better effect of eliminating the DC component of the three-phase inverter current.
[0019] Specifically, applying the three-phase DC component control amount to the three-phase inverter control output signal of the three-phase inverter current control loop specifically includes: obtaining a three-phase voltage control value through dq control, and superimposing the three-phase voltage control value with the three-phase DC component control amount as a three-phase inverter control output signal. The three-phase inverter current control loop of this solution adopts dq control, and directly superimposes the three-phase DC component control amount on the three-phase inverter modulation wave (three-phase voltage control value), thereby realizing the DC component control of the three-phase inverter current.
[0020] Of course, the three-phase inverter current control loop of the present invention is not limited to the above two types, and the three-phase inverter current control can be performed according to other control methods. It only needs to positively superimpose the three-phase DC component control amount on the parameters of the three-phase inverter current control and adjust the three-phase inverter current control parameters to achieve decoupling of the DC component of the three-phase inverter current and effectively eliminate the three-phase inverter current control.
[0021] More specifically, obtaining the three-phase voltage control value through dq control specifically includes: subtracting the q-axis component and d-axis component of the inverter current sampled from the given q-axis component and d-axis component of the three-phase inverter current, respectively, and then subjecting them to PI control and limiting processing, and then superimposing them with the q-axis component and d-axis component of the inverter voltage and transmitting them to the dq / adc conversion unit for conversion into a three-phase voltage control value.
[0022] Compared with the prior art, the present invention improves the performance of the present invention by dca and the DC component of the second phase current I dcb Control is performed to obtain the first phase DC component control quantity U dca_ctl and the second phase DC component control quantity U dcb_ctl , then through U dcc_ctl =-U dca_ctl -U dcb_ctl Get the third phase DC component control quantity U dcc_ctl Finally, the three-phase DC component control quantity is obtained, and the three-phase DC component control quantity is applied to the three-phase inverter current control loop to realize the decoupling control of the DC component of the three-phase inverter current. The decoupling effect is good and the calculation is simple and fast. BRIEF DESCRIPTION OF THE DRAWINGS
[0023] Figure 1 It is the circuit diagram of a three-phase inverter.
[0024] Figure 2 It is the circuit diagram of the equivalent model of the three-phase inverter circuit.
[0025] Figure 3 It is the circuit diagram of the DC component model of the three-phase inverter circuit.
[0026] Figure 4 It is a structural diagram of the DC component control module in Example 1.
[0027] Figure 5 It is a structural diagram of the system control module in Example 1.
[0028] Figure 6 It is a structural diagram of the DC component control module in Example 2.
[0029] Figure 7 It is a structural diagram of the three-phase inverter current DC component decoupling control system of the present invention. DETAILED DESCRIPTION
[0030] In order to explain the technical content, structural features, achieved objectives and effects of the present invention in detail, the following is a detailed description in conjunction with the implementation methods and the accompanying drawings.
[0031] Embodiment 1: refer to Figure 7 The present invention discloses a three-phase inverter current DC component decoupling control system, including a DC component sampling module 10, a DC component control module 20 and a system control module 30.
[0032] refer to Figure 7 The DC component sampling module 10 collects the three-phase inverter current to obtain the three-phase inverter current DC component, wherein the three-phase inverter current DC component includes the A-phase current DC component I dca, B phase current DC component I dcb and the DC component of phase C current I dcc .
[0033] The DC component sampling module 10 collects the inverter inductor current in T cycles, and calculates the average value of the inverter inductor current in T cycles to obtain the three-phase inverter current DC component, where T is 1 or an integer greater than or equal to 2. For example, T may be equal to 5.
[0034] refer to Figure 7 The DC component control module 20 controls the A-phase current DC component I dca and the DC component of phase B current I dcb Control is performed to obtain the A-phase DC component control quantity U dca_ctl and B phase DC component control quantity U dcb_ctl , according to U dcc_ctl =-U dca_ctl -U dcb_ctl Get the C phase DC component control quantity U dcc_ctl , the A phase DC component control quantity U dca_ctl , B phase DC component control quantity U dcb_ctl and C phase DC component control quantity U dcc_ctl It constitutes the three-phase DC component control quantity.
[0035] refer to Figure 4 The DC component control module 20 sets the DC component of phase A to 0, and sets the DC component of phase A inverter current i dca As feedback, the error value of phase A is obtained, and the error value of phase A is subjected to PI control to obtain the A phase DC component control quantity U dca_ctl .
[0036] refer to Figure 4 The DC component control module 20 sets the DC component of phase B to 0, and sets the DC component of phase B inverter current i dcb As feedback, the error value of phase B is obtained, and the error value of phase B is subjected to PI control to obtain the B phase DC component control quantity U dcb_ctl .
[0037] refer to Figure 4 , according to U dcc_ctl =-U dca_ctl -U dcb_ctl Get the C phase DC component control quantity U dcc_ctl .
[0038] refer to Figure 1 , is a three-phase inverter circuit, including a switching circuit, an oscillation circuit and a three-phase grid-connected module (three-phase GRID). The switching circuit controls the oscillation frequency of the oscillation circuit. The three-phase inverter inductor current idca 、i dcb 、i dcc is the current value directly sampled from the oscillation circuit.
[0039] The output voltages of the three-phase inverter are U a , U b , U c , which contains the AC component U a *、U b *、U c *, and a DC component U dca , U dcb , U dcc , which can be equivalent to Figure 2 Three-phase inverter circuit equivalent model. a =U a *+U dca , U b =U b *+U dcb , U c =U c *+U dcc .
[0040] Remove the influence of AC component and consider only DC component, and we can get Figure 3 The DC component model of the three-phase inverter circuit, where U dca , U dcb , U dcc are the DC components of the inverter voltage superimposed on the three-phase inverter circuit, r is the equivalent internal resistance of the three-phase inverter circuit, i is dca 、i dcb 、i dcc They are the DC components of the three-phase inverter current respectively.
[0041] It can be obtained that i dca =(2U dca -U dcb -U dcc ) / 3r;i dcb =(2U dcb -U dca -U dcc ) / 3r;i dcc =(2U dcc -U dca -U dcb ) / 3r.
[0042] From the above formula, we can know that the DC component of the A phase inverter current i dca And the inverter voltage DC component U of the three phases A, B, and C dca , U dcb , U dccThe inverter current DC component of each phase is coupled with the inverter voltage DC component of the three phases.
[0043] Let U dcc =-U dca –U dcb , substituting into the above formula, we get the following formula, i dca =U dca / r;i dcb =U dcb / r;i dcc =U dcc / r; From the above formula, we can see that after setting U dcc =-U dca –U dcb After processing, the DC component of the inverter current of the three phases ABC is only related to the DC component voltage of each phase, thus achieving the purpose of decoupling.
[0044] refer to Figure 7 The system control module 30 converts the three-phase DC component control quantity U dca_ctl , U dcb_ctl , U dcc_ctl It acts in the three-phase inverter current control loop to achieve decoupling control of the DC component of the three-phase inverter current.
[0045] refer to Figure 5 The system control module 30 sets the three-phase DC component control quantity U dca_ctl , U dcb_ctl , U dcc_ctl Acting on the three-phase inverter current control loop to obtain the three-phase inverter control output signal U a_ctl , U b_ctl , U c_ctl , the three-phase inverter control output signal U a_ctl , U b_ctl , U c_ctl The PWM signal generator 40 is obtained and transmitted to the three-phase inverter, thereby realizing the control of the DC component of the three-phase inverter current.
[0046] refer to Figure 5 The system control module 30 respectively controls the three-phase DC component control quantity U dca_ctl , U dcb_ctl , U dcc_ctl The inverter current of the corresponding phase is given by i aref 、i bref 、i cref The new inverter current is superimposed as the new inverter current setting, and the inverter current sampling i of the corresponding phase is subtracted from the new inverter current setting. inva 、i invb 、i invcThe three-phase inverter control loop error values are obtained respectively, and the three-phase inverter control loop error values are independently subjected to PI control and repeated control to obtain the three-phase inverter control output signal U a_ctl , U b_ctl , U c_ctl .
[0047] Embodiment 2: refer to Figure 6 Different from the first embodiment, in the second embodiment, the system control module 30 obtains the three-phase voltage control value U through dq control. a1_ctl , U b1_ctl , U c1_ctl , the three-phase voltage control value U a1_ctl , U b1_ctl , U c1_ctl Respectively with the three-phase DC component control quantity U dca_ctl , U dcb_ctl , U dcc_ctl After superposition, it is used as the three-phase inverter control output signal U a_ctl , U b_ctl , U c_ctl The three-phase inverter current control loop of this scheme adopts dq control, which controls the three-phase DC component U dca_ctl , U dcb_ctl , U dcc_ctl Directly superimposed on the three-phase voltage control value U a1_ctl , U b1_ctl , U c1_ctl ), thereby realizing the DC component control of the three-phase inverter current.
[0048] refer to Figure 5 The system control module 30 converts the given q-axis component i of the three-phase inverter current q_ref and the d-axis component i d_ref Subtract the q-axis component i of the inverter current sampling q_inv and the d-axis component i d_inv After PI control and limiting processing, it is combined with the q-axis component U d_grid and the d-axis component U q_grid After superposition, it is transmitted to the dq / adc conversion unit 31 and converted into a three-phase voltage control value U a1_ctl , U b1_ctl , U c1_ctl .
[0049] refer to Figures 1 to 6 , describing the control method of the three-phase inverter current DC component decoupling control system of the present invention for decoupling the three-phase inverter current DC component.
[0050] S1, collecting three-phase inverter current to obtain three-phase inverter current DC component, wherein the three-phase inverter current DC component includes A phase current DC component I dca , B phase current DC component I dcb and the DC component of phase C current I dcc The three-phase inverter inductor current i is sampled by the DC component sampling module 10 inva 、i invb 、i invc , calculate the average value of five power frequency cycles and obtain the DC component of phase A current I dca , B phase current DC component I dcb and the DC component of phase C current I dcc .
[0051] S2, set the DC component of phase A to 0, and set the DC component of the inverter current of phase A on the AC side to dca As feedback, the error value of phase A is obtained, and the error value of phase A is subjected to PI control to obtain the A phase DC component control quantity U dca_ctl Set the DC component of phase B to 0 and set the DC component of phase B inverter current on the AC side to dcb As feedback, the error value of phase B is obtained, and the error value of phase B is subjected to PI control to obtain the B phase DC component control quantity U dcb_ctl The inverter voltage DC component of phase A is controlled by U dca_ctl Take the inverse and subtract the DC component control quantity U of the inverter phase voltage of phase B dcb_ctl , and obtain the phase voltage DC component control quantity U of phase C dcc_ctl , that is, according to U dcc_ctl =-U dca_ctl -U dcb_ctl Get the C phase DC component control quantity U dcc_ctl .
[0052] S3, respectively set the three-phase DC component control quantity U dca_ctl , U dcb_ctl , U dcc_ctl The inverter current of the corresponding phase is given by i aref 、i bref 、i cref The new inverter current is superimposed as the new inverter current setting, and the inverter current sampling i of the corresponding phase is subtracted from the new inverter current setting. inva 、i invb 、i invc The three-phase inverter control loop error values are obtained respectively, and the three-phase inverter control loop error values are independently subjected to PI control and repeated control and then superimposed to obtain the three-phase inverter control output signal U a_ctl , U b_ctl , U c_ctl , the three-phase inverter control output signal Ua_ctl , U b_ctl , U c_ctl The PWM signal generator 40 is obtained and transmitted to the three-phase inverter, thereby realizing the control of the DC component of the three-phase inverter current.
[0053] Of course, in step S3, the q-axis component i given by the three-phase inverter current can also be q_ref and the d-axis component i d_ref Subtract the q-axis component i of the inverter current sampling q_inv and the d-axis component i d_inv After PI control and limiting processing, it is combined with the q-axis component U d_grid and the d-axis component U q_grid After superposition, it is transmitted to the dq / adc conversion unit 31 and converted into a three-phase voltage control value U a1_ctl , U b1_ctl , U c1_ctl , the three-phase voltage control value U a1_ctl , U b1_ctl , U c1_ctl Respectively with the three-phase DC component control quantity U dca_ctl , U dcb_ctl , U dcc_ctl After superposition, it is used as the three-phase inverter control output signal U a_ctl , U b_ctl , U c_ctl , the three-phase inverter control output signal U a_ctl , U b_ctl , U c_ctl The PWM signal generator 40 is obtained and transmitted to the three-phase inverter, thereby realizing the control of the DC component of the three-phase inverter current.
[0054] The above disclosure is only the preferred embodiment of the present invention, which certainly cannot be used to limit the scope of rights of the present invention. Therefore, equivalent changes made according to the scope of the patent application of the present invention are still within the scope covered by the present invention.
Claims
1. A three-phase inverter current DC component decoupling control system, characterized in that: include: The DC component sampling module collects the three-phase inverter current to obtain the three-phase inverter current DC component, wherein the three-phase inverter current DC component includes the first phase current DC component I dca , the DC component of the second phase current I dcb and the third phase current DC component I dcc ; The DC component control module controls the DC component I of the first phase current respectively. dca and the second phase current DC component I dcb Control is performed to obtain the first phase DC component control quantity U dca_ctl and the second phase DC component control quantity U dcb_ctl , according to U dcc_ctl =-U dca_ctl -U dcb_ctl Get the third phase DC component control quantity U dcc_ctl , the first phase DC component control quantity U dca_ctl , the second phase DC component control quantity U dcb_ctl and the third phase DC component control quantity U dcc_ctl Composed of three-phase DC component control quantity; The system control module applies the three-phase DC component control quantity to the three-phase inverter current control loop to achieve decoupling control of the DC component of the three-phase inverter current.
2. The three-phase inverter current DC component decoupling control system according to claim 1, characterized in that: The DC component sampling module collects the inverter inductor current in T cycles, and calculates the average value of the inverter inductor current in T cycles to obtain the DC component of the three-phase inverter current, where T is 1 or an integer greater than or equal to 2.
3. The three-phase inverter current DC component decoupling control system according to claim 1, characterized in that: The DC component control module sets the DC component of the first phase to 0, and sets the DC component of the first phase inverter current i dca As feedback, the error value of the first phase is obtained, and the error value of the first phase is subjected to PI control to obtain the first phase DC component control quantity U dca_ctl The DC component control module sets the DC component of the second phase to 0, and sets the DC component of the second phase inverter current on the AC side to i dcb As feedback, the error value of the second phase is obtained, and the error value of the second phase is subjected to PI control to obtain the second phase DC component control quantity U dcb_ctl .
4. The three-phase inverter current DC component decoupling control system according to claim 1, characterized in that: The system control module applies the three-phase DC component control quantity to the three-phase inverter current control loop to obtain a three-phase inverter control output signal, and transmits the three-phase inverter control output signal to the PWM signal generator of the three-phase inverter, thereby realizing the control of the DC component of the three-phase inverter current.
5. The three-phase inverter current DC component decoupling control system according to claim 4, characterized in that: The system control module respectively superimposes the three-phase DC component control quantity and the inverter current setting of the corresponding phase as a new inverter current setting, subtracts the inverter current sampling of the corresponding phase from the new inverter current setting to obtain three-phase inverter control loop error values, and independently subjects the three-phase inverter control loop error values to PI control and repeated control to obtain the three-phase inverter control output signal.
6. The three-phase inverter current DC component decoupling control system according to claim 4, characterized in that: The system control module obtains three-phase voltage control values through dq control, and superimposes the three-phase voltage control values with the three-phase DC component control quantities respectively as three-phase inverter control output signals.
7. The three-phase inverter current DC component decoupling control system according to claim 6, characterized in that: The system control module obtains the three-phase voltage control value through dq control as follows: the system control module subtracts the q-axis component and d-axis component of the inverter current sampled from the given q-axis component and d-axis component of the three-phase inverter current, respectively, and performs PI control and limiting processing on them, and then superimposes them with the q-axis component and d-axis component of the inverter voltage and transmits them to the dq / adc conversion unit for conversion into a three-phase voltage control value.
8. A three-phase inverter current DC component decoupling control method, characterized in that: include: The three-phase inverter current is collected to obtain a three-phase inverter current DC component, wherein the three-phase inverter current DC component includes a first phase current DC component I dca , the DC component of the second phase current I dcb and the third phase current DC component I dcc ; The first phase current DC component I dca and the second phase current DC component I dcb Control is performed to obtain the first phase DC component control quantity U dca_ctl and the second phase DC component control quantity U dcb_ctl ; According to U dcc_ctl =-U dca_ctl -U dcb_ctl Get the third phase DC component control quantity U dcc_ctl ; The first phase DC component control quantity U dca_ctl , the second phase DC component control quantity U dcb_ctl and the third phase DC component control quantity U dcc_ctl Composed of three-phase DC component control quantity; The three-phase DC component control quantity is applied to the three-phase inverter current control loop to realize decoupling control of the DC component of the three-phase inverter current.
9. The three-phase inverter current DC component decoupling control method according to claim 8, characterized in that: Collecting the three-phase inverter current to obtain the three-phase inverter current DC component specifically includes: collecting the inverter inductor current in T cycles, and calculating the average value of the inverter inductor current in T cycles to obtain the three-phase inverter current DC component, where T is 1 or an integer greater than or equal to 2.
10. The three-phase inverter current DC component decoupling control method according to claim 8, characterized in that: The first phase current DC component I dca and the second phase current DC component I dcb Control is performed to obtain the first phase DC component control quantity U dca_ctl and the second phase DC component control quantity U dcb_ctl Specifically, the first phase inverter current DC component i on the AC side is converted into dca As feedback, the error value of the first phase is obtained, and the error value of the first phase is subjected to PI control to obtain the first phase DC component control quantity U dca_ctl ; Set the DC component of the second phase to 0, and set the DC component of the second phase inverter current on the AC side to dcb As feedback, the error value of the second phase is obtained, and the error value of the second phase is subjected to PI control to obtain the second phase DC component control quantity U dcb_ctl .
11. The three-phase inverter current DC component decoupling control method according to claim 8, characterized in that: Applying the three-phase DC component control quantity to the three-phase inverter current control loop specifically includes: applying the three-phase DC component control quantity to the three-phase inverter current control loop to obtain a three-phase inverter control output signal, and transmitting the three-phase inverter control output signal to the PWM signal generator of the three-phase inverter, thereby realizing the control of the DC component of the three-phase inverter current.
12. The three-phase inverter current DC component decoupling control method according to claim 11, characterized in that: Applying the three-phase DC component control amount to the three-phase inverter current control loop to generate a three-phase inverter control output signal specifically includes: The three-phase DC component control quantity is superimposed on the inverter current setting of the corresponding phase as a new inverter current setting, and the inverter current sampling of the corresponding phase is subtracted from the new inverter current setting to obtain the three-phase inverter control loop error values respectively. After the three-phase inverter control loop error values are independently subjected to PI control and repeated control, the three-phase inverter control output signal is obtained.
13. The three-phase inverter current DC component decoupling control method according to claim 11, characterized in that: Applying the three-phase DC component control amount to the three-phase inverter current control loop to obtain a three-phase inverter control output signal specifically includes: obtaining a three-phase voltage control value through dq control, and superimposing the three-phase voltage control value with the three-phase DC component control amount as a three-phase inverter control output signal.
14. The three-phase inverter current DC component decoupling control method according to claim 13, characterized in that: The three-phase voltage control value is obtained through dq control, which specifically includes: subtracting the q-axis component and d-axis component of the inverter current sampled from the given q-axis component and d-axis component of the three-phase inverter current, respectively, and then subjecting them to PI control and limiting processing, and then superimposing them with the q-axis component and d-axis component of the inverter voltage and transmitting them to the dq / adc conversion unit for conversion into a three-phase voltage control value.