A static error-free APF current inner loop control system and control method

Abstract

The application embodiment provides an APF current inner loop control system and control method without static error, which comprises the following steps: according to a specific proportion, the output current sampling signal of the current control period and the output current signal of the current control period predicted in the last period are used to form a correction current; the correction current is used to generate a current prediction signal of the next period; then, the current prediction signal is used to generate a voltage signal; meanwhile, the correction current is used to generate an error compensation signal, and the error compensation signal is added to the voltage signal to obtain a voltage control signal input to a PWM modulation module to drive the APF. The scheme can realize the APF control without delay dynamic tracking, and can solve the steady-state error of current tracking caused by the system parameter deviation, and improve the accuracy and reliability of the control.

Description

TECHNICAL FIELD

[0001] The embodiment of the present application relates to the technical field of active power filter, in particular to a static error-free APF current inner loop control system and control method. BACKGROUND

[0002] In the new power system, the high-order harmonic is increasing. Although the current control method of the traditional APF is qualified in inhibiting the low-order harmonic of the power grid, for the compensation of the high-order harmonic, the current loop needs to have a very high bandwidth, and the traditional APF current control method is difficult to achieve.

[0003] To this end, the present application provides a static error-free APF current inner loop control system and control method. The method forms a correction current according to a specific proportion of the output current sampling signal of the current control period and the output current signal of the current control period predicted in the last period; then generates a current prediction signal of the next period by using the correction current; further generates a voltage signal by using the current prediction signal; and simultaneously generates an error compensation signal by using the correction current, and adds the error compensation signal to the voltage signal to obtain a voltage control signal input to a PWM modulation module to drive the APF.

[0004] The scheme can realize the APF control without delay dynamic tracking, and can also solve the steady-state error of current tracking caused by parameter deviation. SUMMARY

[0005] The present application provides a static error-free APF current inner loop control system and control method, which forms a correction current according to a specific proportion of the output current sampling signal of the current control period and the output current signal of the current control period predicted in the last period; then generates a current prediction signal of the next period by using the correction current; further generates a voltage signal by using the current prediction signal; and simultaneously generates an error compensation signal by using the correction current, and adds the error compensation signal to the voltage signal to obtain a voltage control signal input to a PWM modulation module to drive the APF. The scheme can realize the APF control without delay dynamic tracking, and can also solve the steady-state error of current tracking caused by system parameter deviation, and improves the accuracy and reliability of control.

[0006] In the first aspect, the embodiment of the present application provides a static error-free APF current inner loop control system, which comprises a voltage acquisition module, a current acquisition module, a voltage prediction module, a current prediction module, a voltage generation module, a PWM generation module, an error compensation module and an actual circuit.

[0007] The input end of the voltage acquisition module is connected with the common coupling point of the actual circuit, the output end of the voltage acquisition module is connected with the input end of the voltage prediction module and the input end of the current prediction module respectively; the input end of the current acquisition module is connected with the filter inductor of the actual circuit, the output end of the current acquisition module is connected with the input end of the current prediction module; the input end of the current prediction module is also connected with the output end of the delay module; the output end of the current prediction module is connected with the input end of the error compensation module and the input end of the voltage generation module respectively; the input of the voltage generation module is also used for receiving the external compensation current instruction and the output of the voltage prediction module; the error compensation module further comprises a compensation current instruction input end used for receiving the external compensation current instruction; the output of the voltage generation module is added with the output of the error compensation module, and then is sequentially connected with the limiting module, the delay module and the PWM generation module; the output end of the PWM generation module as the output end of the control module is connected with the APF inverter in the actual circuit;

[0008] The voltage acquisition module is used for acquiring the voltage value of the common coupling point of the actual circuit, obtaining a voltage sampling signal, and transmitting the voltage sampling signal to the voltage prediction module and the current prediction module; the voltage prediction module is used for obtaining a voltage prediction signal according to the voltage sampling signal at the current moment, and outputting the voltage prediction signal to the voltage generation module; the current acquisition module is used for acquiring the current value of the filter inductor of the actual circuit, obtaining a current sampling signal, and transmitting the current sampling signal to the current prediction module; the current prediction module is used for constructing a correction current according to the current sampling signal at the current moment and the current sampling signal at the current moment predicted at the last moment, obtaining a current prediction signal by using the correction current, the current sampling signal, the voltage sampling signal and the output signal of the delay module, and outputting the current prediction signal to the voltage generation module and the error compensation module; the error compensation module is used for obtaining an error compensation signal according to the compensation current instruction and the output of the current prediction module; the voltage generation module is used for obtaining a voltage signal according to the current prediction signal, the voltage prediction signal and the compensation current instruction; the voltage signal and the error compensation signal are added to obtain a voltage control signal, and the voltage control signal is output to the PWM generation module through the limiting module and the delay module; the PWM generation module is used for converting the voltage control signal into a PWM wave signal to drive the APF inverter.

[0009] Optionally, the discrete control model of the actual circuit is:

[0010] , ;

[0011] wherein, T s is a preset sampling period, ω0 is a rated angular frequency, L1 is the filter inductance, R1 is the parasitic resistance in the actual circuit, A and B are constants, u d (k) is the d-axis component of the voltage signal in the synchronous rotating coordinate system at time k, u q (k) is the q-axis component of the voltage signal in the synchronous rotating coordinate system at time k; u dpcc (k) is the d-axis component of the voltage sampling signal in the synchronous rotating coordinate system at time k, u qpcc (k) is the q-axis component of the voltage sampling signal in the synchronous rotating coordinate system at time k; i Ld (k) is the d-axis component of the current sampling signal in the synchronous rotating coordinate system at time k, i Lq (k) is the q-axis component of the current sampling signal in the synchronous rotating coordinate system at time k; i Ld (k+1) is the d-axis component of the current sampling signal in the synchronous rotating coordinate system at time k+1, i Lq (k+1) is the q-axis component of the current sampling signal in the synchronous rotating coordinate system at time k+1.

[0012] Optionally, the core control equation of the voltage prediction module is:

[0013] ;

[0014] wherein, T dpcc_p (k+1) is the d-axis component of the voltage prediction signal in the synchronous rotating coordinate system at time k+1, u qpcc_p (k+1) is the q-axis component of the voltage prediction signal in the synchronous rotating coordinate system at time k+1, u dpcc (k) is the d-axis component of the voltage sampling signal in the synchronous rotating coordinate system at time k, u qpcc (k) is the q-axis component of the voltage sampling signal in the synchronous rotating coordinate system at time k, u dpcc (k-1) is the d-axis component of the voltage sampling signal in the synchronous rotating coordinate system at time k-1, u qpcc (k-1) is the q-axis component of the voltage sampling signal in the synchronous rotating coordinate system at time k-1.

[0015] Optionally, the core control equation of the current prediction module is:

[0016] wherein, T s is a preset sampling period, ω0 is a rated angular frequency, B is a constant, B pis the parameter estimation value of B, X1 represents the proportional relationship between the actual current and the predicted current in the correction current, i dp (k+1) is the d-axis component of the current prediction signal in the synchronous rotating coordinate system at k+1 moment, i qp (k+1) is the q-axis component of the current prediction signal in the synchronous rotating coordinate system at k+1 moment, i dp (k) is the d-axis component of the current prediction signal in the synchronous rotating coordinate system at k moment, i qp (k) is the q-axis component of the current prediction signal in the synchronous rotating coordinate system at k moment; u d (k) is the d-axis component of the voltage signal in the synchronous rotating coordinate system at k moment, u q (k) is the q-axis component of the voltage signal in the synchronous rotating coordinate system at k moment; u dpcc (k) is the d-axis component of the voltage sampling signal in the synchronous rotating coordinate system at k moment, u qpcc (k) is the q-axis component of the voltage sampling signal in the synchronous rotating coordinate system at k moment; i Ld (k) is the d-axis component of the current sampling signal in the synchronous rotating coordinate system at k moment, i Lq (k) is the q-axis component of the current sampling signal in the synchronous rotating coordinate system at k moment.

[0017] Optionally, the core control equation of the error compensation module is:

[0018] ; wherein T s is a preset sampling period, ω0 is a rated angular frequency, u d_cor (k+1) is the d-axis component of the error compensation signal, u q_cor (k+1) is the p-axis component of the error compensation signal, B is a constant, B p is the parameter estimation value of B, B p -1 represents the reciprocal of Bp, X3 is a compensation coefficient, i Ld (k) is the d-axis component of the current sampling signal in the synchronous rotating coordinate system at k moment, i Lq (k) is the q-axis component of the current sampling signal in the synchronous rotating coordinate system at k moment, i dp (k) is the d-axis component of the current prediction signal in the synchronous rotating coordinate system at k moment, i qp (k) is the q-axis component of the current prediction signal in the synchronous rotating coordinate system at k moment.

[0019] In a second aspect, the application further provides an APF current inner loop control method without static error, applied to the APF current inner loop control system without static error in any of the first aspect of the application, comprising:

[0020] acquiring, by the voltage acquisition module, the voltage value of the actual circuit common coupling point to obtain a voltage sampling signal, and transmitting the voltage sampling signal to the voltage prediction module and the current prediction module;

[0021] obtaining, by the voltage prediction module, a voltage prediction signal according to the voltage sampling signal at the current time, and outputting the voltage prediction signal to the voltage generation module;

[0022] acquiring, by the current acquisition module, the current value of the filter inductor of the actual circuit to obtain a current sampling signal, and transmitting the current sampling signal to the current prediction module;

[0023] obtaining, by the current prediction module, a correction current according to the current sampling signal at the current time and the current sampling signal at the current time predicted at the last time, and obtaining a current prediction signal by using the correction current, the current sampling signal, the voltage sampling signal and the output signal of the delay module, and outputting the current prediction signal to the voltage generation module and the error compensation module;

[0024] obtaining, by the error compensation module, an error compensation signal according to the compensation current instruction and the output of the current prediction module;

[0025] obtaining, by the voltage generation module, a voltage signal according to the current prediction signal, the voltage prediction signal and the compensation current instruction; adding the voltage signal and the error compensation signal to obtain a voltage control signal, and outputting the voltage control signal to the PWM generation module through the limiting module and the delay module;

[0026] converting, by the PWM generation module, the voltage control signal into a PWM wave signal to drive the APF inverter.

[0027] Optionally, after acquiring, by the voltage acquisition module, the voltage value of the actual circuit common coupling point to obtain a voltage sampling signal, before transmitting the voltage sampling signal to the voltage prediction module and the current prediction module, the method further comprises:

[0028] based on the formula , the three-phase output voltage of the common coupling point is converted into voltage in the synchronous rotating coordinate system; wherein θ represents the rotation angle of the synchronous rotating coordinate system, u dpcc and u qpcc respectively represent the d-axis and q-axis components of the common coupling point voltage in the synchronous rotating coordinate system, u pcc_a , u pcc_b and u pcc_crepresenting the three-phase output voltage;

[0029] After the current acquisition module is used to acquire the current value of the filter inductor of the actual circuit to obtain a current sampling signal, before the current sampling signal is transmitted to the current prediction module, the method further comprises:

[0030] based on the formula , the three-phase output current of the filter inductor is converted into a current in a synchronous rotating coordinate system; wherein i Ld and i Lq respectively represent the d-axis and q-axis components of the three-phase output current in the synchronous rotating coordinate system, i La , i Lb , and i Lc represent the three-phase output current.

[0031] Optionally, the voltage prediction module is used to obtain a voltage prediction signal according to the voltage sampling signal at the current time, comprising:

[0032] The voltage prediction module is used to obtain a voltage prediction signal according to the voltage sampling signal at the current time, based on the formula ; wherein u dpcc_p (k+1) is the d-axis component of the voltage prediction signal in the synchronous rotating coordinate system at k+1 time, u qpcc_p (k+1) is the q-axis component of the voltage prediction signal in the synchronous rotating coordinate system at k+1 time, u dpcc (k) is the d-axis component of the voltage sampling signal in the synchronous rotating coordinate system at k time, u qpcc (k) is the q-axis component of the voltage sampling signal in the synchronous rotating coordinate system at k time, u dpcc (k-1) is the d-axis component of the voltage sampling signal in the synchronous rotating coordinate system at k-1 period, u qpcc (k-1) is the q-axis component of the voltage sampling signal in the synchronous rotating coordinate system at k-1 period.

[0033] Optionally, the current prediction signal is obtained by using the corrected current, the current sampling signal, the voltage sampling signal, and the output signal of the delay module, comprising:

[0034] The current prediction module is used to obtain the d-axis component idp(k+1) and the q-axis component iq(k+1) of the current prediction signal in the synchronous rotating coordinate system at the next acquisition time, based on the formula ; wherein, is the corrected current expression, T s is a preset sampling period, ω0 is a rated angular frequency, and B is a constant. pis a parameter estimation value of B, X1 represents a proportional relationship between an actual current and a predicted current in a correction current, i dp is a d-axis component of the current prediction signal in a synchronous rotating coordinate system at k+1 moment, i qp is a q-axis component of the current prediction signal in a synchronous rotating coordinate system at k+1 moment, i dp is a d-axis component of the current prediction signal in a synchronous rotating coordinate system at k moment, i qp is a q-axis component of the current prediction signal in a synchronous rotating coordinate system at k moment; u d is a d-axis component of the voltage signal in a synchronous rotating coordinate system at k moment, u q is a q-axis component of the voltage signal in a synchronous rotating coordinate system at k moment; u dpcc is a d-axis component of the voltage sampling signal in a synchronous rotating coordinate system at k moment, u qpcc is a q-axis component of the voltage sampling signal in a synchronous rotating coordinate system at k moment; i Ld is a d-axis component of the current sampling signal in a synchronous rotating coordinate system at k moment, i Lq is a q-axis component of the current sampling signal in a synchronous rotating coordinate system at k moment.

[0035] Optionally, the voltage generation module is used to obtain a voltage signal according to the current prediction signal, the voltage prediction signal and the compensation current instruction, including:

[0036] The voltage generation module is used to obtain a voltage signal according to the current prediction signal, the voltage prediction signal and the compensation current instruction based on the formula ; wherein, T s is a preset sampling period, ω0 is a rated angular frequency, u d is a d-axis component of the voltage signal in a synchronous rotating coordinate system at k+1 moment, u q is a q-axis component of the voltage signal in a synchronous rotating coordinate system at k+1 moment; u dpcc_p is a d-axis component of the voltage prediction signal in a synchronous rotating coordinate system at k+1 moment, u qpcc_p is a q-axis component of the voltage prediction signal in a synchronous rotating coordinate system at k+1 moment; i dref is a d-axis component of the compensation current instruction in a synchronous rotating coordinate system at k moment, i qref is a q-axis component of the compensation current instruction in a synchronous rotating coordinate system at k moment, i dref is a d-axis component of the compensation current instruction in a synchronous rotating coordinate system at k-1 period, i qref(k-1) is the q-axis component of the compensation current command in the k-1 period synchronous rotating coordinate system; i dp (k+1) is the d-axis component of the current prediction signal in the k+1 moment synchronous rotating coordinate system, i qp (k+1) is the q-axis component of the current prediction signal in the k+1 moment synchronous rotating coordinate system; B is a constant, B p is the parameter estimation value of B, B p -1 is the inverse of B p ; X2 represents the ratio of the current prediction signal to the compensation current command.

[0037] The embodiment of the present application provides a static error-free APF current inner loop control system and a control method, the system comprises a control module and an actual circuit; the control module comprises a voltage acquisition module, a current acquisition module, a voltage prediction module, a current prediction module, a voltage generation module, a limiting module, a delay module, an error compensation module and a PWM generation module; the actual circuit comprises an APF inverter and a filter inductor, the APF inverter and the filter inductor are connected in series and connected with a grid side; the input end of the voltage acquisition module is connected with a common coupling point of the actual circuit, the output end of the voltage acquisition module is connected with the input end of the voltage prediction module and the input end of the current prediction module; the input end of the current acquisition module is connected with the filter inductor of the actual circuit, and the output end of the current acquisition module is connected with the input end of the current prediction module; the input end of the current prediction module is also connected with the output end of the delay module; the output end of the current prediction module is connected with the input end of the error compensation module and the input end of the voltage generation module; the input of the voltage generation module is also used for receiving an external compensation current instruction and the output of the voltage prediction module; the error compensation module further comprises a compensation current instruction input end used for receiving the external compensation current instruction; the output of the voltage generation module and the output of the error compensation module are added, and then sequentially connected with the limiting module, the delay module and the PWM generation module; the output end of the PWM generation module is connected with the APF inverter in the actual circuit as the output end of the control module; the voltage acquisition module is used for acquiring the voltage value of the common coupling point of the actual circuit, obtaining a voltage sampling signal, and transmitting the voltage sampling signal to the voltage prediction module and the current prediction module; the voltage prediction module is used for obtaining a voltage prediction signal according to the voltage sampling signal at the current moment, and outputting the voltage prediction signal to the voltage generation module; the current acquisition module is used for acquiring the current value of the filter inductor of the actual circuit, obtaining a current sampling signal, and transmitting the current sampling signal to the current prediction module; the current prediction module is used for constructing a correction current according to the current sampling signal at the current moment and the current sampling signal at the current moment predicted at the last moment, obtaining a current prediction signal by using the correction current, the current sampling signal, the voltage sampling signal and the output signal of the delay module, and outputting the current prediction signal to the voltage generation module and the error compensation module; the error compensation module is used for obtaining an error compensation signal according to the compensation current instruction and the output of the current prediction module; the voltage generation module is used for obtaining a voltage signal according to the current prediction signal, the voltage prediction signal and the compensation current instruction; the voltage signal and the error compensation signal are added to obtain a voltage control signal, and the voltage control signal is output to the PWM generation module through the limiting module and the delay module; and the PWM generation module is used for converting the voltage control signal into a PWM wave signal to drive the APF inverter.The technical scheme has the output current sampling signal of the current control period and the output current signal of the current control period predicted in the last period according to a specific proportion to form a correction current; the correction current is used to generate a current prediction signal of the next period; then the voltage signal is generated; the error compensation signal is generated by using the correction current and added to the voltage signal to obtain the voltage control signal input to the PWM modulation module to drive the APF. The scheme can realize the APF control of the non-delay dynamic tracking, solve the steady-state error of the current tracking caused by the system parameter deviation, and improve the accuracy and reliability of the control. BRIEF DESCRIPTION OF DRAWINGS

[0038] Figure 1 is a structure schematic diagram of an APF current inner loop control system without static error provided by an embodiment of the application;

[0039] Figure 2 is a practical circuit topology structure diagram provided by an embodiment of the application;

[0040] Figure 3 is a flow schematic diagram of an APF current inner loop control method without static error provided by an embodiment of the application;

[0041] Figure 4 is a current change following curve diagram under the APF current inner loop net difference control method without static error;

[0042] Figure 5 is a current change following curve diagram of the prior art. DETAILED DESCRIPTION

[0043] The application will be further described below in combination with the drawings and embodiments. It can be understood that the specific embodiments described herein are only used to explain the application, but not to limit the application. In addition, it should be noted that, for the convenience of description, only the parts related to the application are shown in the drawings, but not all the structures.

[0044] The terms used in the embodiments of the present application are merely for the purpose of describing specific embodiments and are not intended to limit the present application. It should be noted that the orientation terms such as "upper", "lower", "left", "right", and the like described in the embodiments of the present application are described in the angle shown in the drawings, and should not be understood as a limitation on the embodiments of the present application. In addition, in context, it should also be understood that when referring to an element being formed "on" or "under" another element, it can not only be directly formed "on" or "under" another element, but also indirectly formed "on" or "under" another element through an intermediate element. The terms "first", "second", and the like are only for the purpose of description and do not represent any order, quantity or importance, but are only used to distinguish different components. For those skilled in the art, the specific meanings of the above terms in the present application can be understood according to the specific circumstances.

[0045] The term "including" and its variants used in the present application are open inclusion, that is, "including but not limited to". The term "based on" is "at least partially based on". The term "one embodiment" means "at least one embodiment".

[0046] It should be noted that the concepts of "first", "second", and the like mentioned in the present application are only used to distinguish the corresponding content, and are not used to limit the order or mutual dependency.

[0047] It should be noted that the modification of "one" or "multiple" in the present application is illustrative and not limiting, and those skilled in the art should understand that unless the context clearly indicates otherwise, it should be understood as "one or more".

[0048] Figure 1 is a structural schematic diagram of an APF current inner loop control system without static error provided by an embodiment of the present application, Figure 2 is an actual circuit topology structure diagram provided by an embodiment of the present application, referring to Figure 1 、 Figure 2 The system includes a control module and an actual circuit; the control module includes a voltage acquisition module 10, a current acquisition module 20, a voltage prediction module 30, a current prediction module 40, a voltage generation module 50, a limiting module 80, a delay module 90, an error compensation module 100 and a PWM generation module 60; the actual circuit includes an APF inverter 71 and a filter inductor 72, and the APF inverter 71 and the filter inductor 72 are connected in series with the grid side Grid.

[0049] The input end of the voltage acquisition module 10 is connected with the common coupling point of the actual circuit, the output end of the voltage acquisition module 10 is connected with the input end of the voltage prediction module 30 and the input end of the current prediction module 40 respectively; the input end of the current acquisition module 20 is connected with the filter inductor 72 of the actual circuit, the output end of the current acquisition module 20 is connected with the input end of the current prediction module 40; the input end of the current prediction module 40 is also connected with the output end of the delay module; the output end of the current prediction module 40 is connected with the input end of the error compensation module and the input end of the voltage generation module 50 respectively; the input of the voltage generation module 50 is also used for receiving the output of the voltage prediction module 30 and the external compensation current instruction; the error compensation module further comprises a compensation current instruction input end used for receiving the external compensation current instruction; the output of the voltage generation module 50 is added with the output of the error compensation module, and then is connected with the limiting module, the delay module and the PWM generation module 60 in sequence; the output end of the PWM generation module 60 as the output end of the control module is connected with the APF inverter 71 in the actual circuit; the voltage acquisition module 10 is used for acquiring the voltage value of the common coupling point of the actual circuit, obtaining a voltage sampling signal and transmitting the voltage sampling signal to the voltage prediction module 30 and the current prediction module 40; the voltage prediction module 30 is used for obtaining a voltage prediction signal according to the voltage sampling signal at the current time and outputting the voltage prediction signal to the voltage generation module 50; the current acquisition module 20 is used for acquiring the current value of the filter inductor 72 of the actual circuit, obtaining a current sampling signal and transmitting the current sampling signal to the current prediction module 40; the current prediction module 40 is used for constructing a correction current according to the current sampling signal at the current time and the current sampling signal at the current time predicted at the last time, obtaining a current prediction signal by using the correction current, the current sampling signal, the voltage sampling signal and the output signal of the delay module, and outputting the current prediction signal to the voltage generation module 50 and the error compensation module; the voltage generation module 50 is used for obtaining a voltage signal according to the current prediction signal, the voltage prediction signal and the compensation current instruction; the error compensation module is used for obtaining an error compensation signal according to the compensation current instruction and the output of the current prediction module 40; the voltage signal and the error compensation signal are added to obtain a voltage control signal, and the voltage control signal is output to the PWM generation module 60 through the limiting module and the delay module; the PWM generation module 60 is used for converting the voltage control signal into a PWM wave signal to drive the APF inverter 71.

[0050] Figure 3 is a flowchart of an APF current inner loop control method without static error provided by the embodiment of the application, and the method will be introduced below with reference to Figure 1 , Figure 3 , Figure 3 The method comprises the following steps.

[0051] S110, collecting the voltage value of the actual circuit common coupling point by using the voltage collection module, obtaining the voltage sampling signal, and transmitting the voltage sampling signal to the voltage prediction module and the current prediction module.

[0052] S111, obtaining the voltage prediction signal according to the voltage sampling signal of the current time by using the voltage prediction module, and outputting the voltage prediction signal to the voltage generation module.

[0053] Specifically, referring to Figure 1 , when APF is applied to the power grid, it needs to detect harmonics and other power quality problems in the power grid, and generate the corresponding compensation current quickly according to the fluctuation, so that the grid side is stable; Therefore, after determining the size of the current that needs to be compensated, the APF needs to output the compensation current of the corresponding size; And the power grid fluctuation is changing, the corresponding compensation current also needs to change, so it is necessary to ensure that the current output by the actual circuit 70 in the APF can change in time according to the change of the current that needs to be compensated, so first of all, the voltage value of the common coupling point PCC of the actual circuit is collected at a preset period, and the voltage value of the common coupling point PCC is transmitted to the voltage prediction module 30, so as to predict the voltage value of the next time by using the voltage prediction module 30.

[0054] S112, collecting the current value of the filter inductance of the actual circuit by using the current collection module, to obtain the current sampling signal, and transmitting the current sampling signal to the current prediction module.

[0055] S113, using the current prediction module to form a correction current according to the current sampling signal of the current time and the current sampling signal of the current time predicted at the last time, and using the correction current, the current sampling signal, the voltage sampling signal and the output signal of the delay module to obtain the current prediction signal, and outputting the current prediction signal to the voltage generation module and the error compensation module.

[0056] Specifically, after collecting the voltage value of the current grid side and predicting the voltage value of the next period, the current value of the actual circuit needs to be collected by using the current collection module 20 to predict the current value of the next period. However, the deviation of system parameters from the rated value will cause the current value output by the actual circuit to be inconsistent with the current value that the actual circuit should output, so as to be unable to provide effective harmonic compensation or reactive power support, therefore, according to the current sampling signal of the current time and the current sampling signal of the current time predicted at the last time, a correction current is formed, and the correction current, the current sampling signal, the voltage sampling signal and the signal output by the delay module 90 at the last time are used to obtain the current prediction signal; The correction current is used to further accurately predict the current.

[0057] S114, obtaining the error compensation signal according to the compensation current instruction and the output of the current prediction module by using the error compensation module.

[0058] The compensation current instruction can be understood as an instruction corresponding to a compensation current required to compensate for fluctuations in the current grid side.

[0059] Specifically, referring to Figure 1 , the error compensation module 100 receives the externally input compensation current instruction and the correction current output by the current prediction module 40, respectively, generates an error compensation signal according to the compensation current instruction and the correction current, and transmits the error compensation signal to the voltage generation module 50 to perform error compensation on the voltage signal of the voltage generation module 50, thereby compensating for the voltage driving the inverter.

[0060] S115, using the voltage generation module to obtain a voltage signal according to the current prediction signal, the voltage prediction signal, and the compensation current instruction; adding the voltage signal and the error compensation signal to obtain a voltage control signal, and outputting the voltage control signal to the PWM generation module through the limiting module and the delay module.

[0061] Specifically, the current prediction module 40 transmits the predicted current prediction signal of the filter inductor 72 in the actual circuit in the next sampling period to the voltage generation module 50, and the voltage prediction module 30 transmits the predicted voltage prediction signal of the grid side in the next sampling period to the voltage generation module 50, and the voltage generation module 50 thereby outputs a voltage signal according to the current prediction signal including the current value of the filter inductor 72 in the next sampling period, the voltage prediction signal including the voltage value of the point of common coupling PCC in the next sampling period, and the compensation current instruction corresponding to the current required by the grid side. Add the voltage signal and the error compensation signal to obtain a voltage control signal, and output the voltage control signal to the PWM generation module 60 through the limiting module 80 and the delay module 90.

[0062] S116, using the PWM generation module to convert the voltage control signal into a PWM wave signal to drive the APF inverter.

[0063] Specifically, after the PWM generation module 60 receives the voltage control signal, it converts the voltage control signal into a PWM wave signal, thereby driving the APF inverter 71 to generate a corresponding compensation current to the grid side, so that the final output compensation current value is equal to the current value corresponding to the compensation current instruction.

[0064] Optionally, referring to Figure 3 , DGs represents the DC side; L1 represents the filter inductor, R1 represents the parasitic resistance, PCC represents the point of common coupling, L line represents the line inductance, R line represents the line parasitic resistance, Grid represents the grid, that is, the three-phase current i Labc and the three-phase voltage u pcc_abcThe filter inductance L1 and the parasitic resistance R1 reach the grid side, if the filter inductance L1 and the parasitic resistance R1 do not conform to the rated value, the actual circuit 70 will output a current to the grid side which does not conform to the required compensation current of the grid side, thus an error compensation signal including an error compensation coefficient is output, thereby compensating the current deviation caused by the deviation of the filter inductance L1 and the parasitic resistance R1 from the rated value. Figure 4 is a current change following curve diagram under the APF current inner loop net difference free control method without static error, Figure 5 is a current change following curve diagram of the prior art, referring to Figure 4 , Figure 5 , i* d and i* q are the d-axis component and the q-axis component of the compensation current instruction respectively, i d and i q are the d-axis component and the q-axis component of the actual output following current, as shown in the figure, the technical scheme of the embodiment of the present application can realize fast following of the compensation current instruction and does not have any current control steady state error even in the case of great error of the system filter parameters.

[0065] The embodiment of the present application provides a static error-free APF current inner loop control system and a control method, the system comprises a control module and an actual circuit; the control module comprises a voltage acquisition module, a current acquisition module, a voltage prediction module, a current prediction module, a voltage generation module, a limiting module, a delay module, an error compensation module and a PWM generation module; the actual circuit comprises an APF inverter and a filter inductor, the APF inverter and the filter inductor are connected in series and connected with a grid side; the input end of the voltage acquisition module is connected with a common coupling point of the actual circuit, the output end of the voltage acquisition module is connected with the input end of the voltage prediction module and the input end of the current prediction module; the input end of the current acquisition module is connected with the filter inductor of the actual circuit, and the output end of the current acquisition module is connected with the input end of the current prediction module; the input end of the current prediction module is also connected with the output end of the delay module; the output end of the current prediction module is connected with the input end of the error compensation module and the input end of the voltage generation module; the input of the voltage generation module is also used for receiving an external compensation current instruction and the output of the voltage prediction module; the error compensation module further comprises a compensation current instruction input end used for receiving the external compensation current instruction; the output of the voltage generation module and the output of the error compensation module are added, and then sequentially connected with the limiting module, the delay module and the PWM generation module; the output end of the PWM generation module is connected with the APF inverter in the actual circuit as the output end of the control module; the voltage acquisition module is used for acquiring the voltage value of the common coupling point of the actual circuit, obtaining a voltage sampling signal, and transmitting the voltage sampling signal to the voltage prediction module and the current prediction module; the voltage prediction module is used for obtaining a voltage prediction signal according to the voltage sampling signal at the current moment, and outputting the voltage prediction signal to the voltage generation module; the current acquisition module is used for acquiring the current value of the filter inductor of the actual circuit, obtaining a current sampling signal, and transmitting the current sampling signal to the current prediction module; the current prediction module is used for constructing a correction current according to the current sampling signal at the current moment and the current sampling signal at the current moment predicted at the last moment, obtaining a current prediction signal by using the correction current, the current sampling signal, the voltage sampling signal and the output signal of the delay module, and outputting the current prediction signal to the voltage generation module and the error compensation module; the error compensation module is used for obtaining an error compensation signal according to the compensation current instruction and the output of the current prediction module; the voltage generation module is used for obtaining a voltage signal according to the current prediction signal, the voltage prediction signal and the compensation current instruction; the voltage signal and the error compensation signal are added to obtain a voltage control signal, and the voltage control signal is output to the PWM generation module through the limiting module and the delay module; and the PWM generation module is used for converting the voltage control signal into a PWM wave signal to drive the APF inverter.The technical scheme above forms a correction current by a certain proportion of the output current sampling signal of the current control period and the output current signal of the current control period predicted in the last period; generates a current prediction signal of the next period by using the correction current; further generates a voltage signal by using the current prediction signal; generates an error compensation signal by using the correction current, and adds the error compensation signal to the voltage signal to obtain a voltage control signal input to a PWM modulation module to drive the APF. The scheme can realize APF control without time delay dynamic tracking, and can solve the steady-state error of current tracking caused by system parameter deviation, and improve the accuracy and reliability of control.

[0066] Optionally, after obtaining the voltage sampling signal by using the voltage acquisition module to acquire the voltage value of the actual circuit common coupling point, before transmitting the voltage sampling signal to the voltage prediction module and the current prediction module, the method further comprises:

[0067] Converting the three-phase output voltage of the common coupling point into voltage on the axis of the synchronous rotating coordinate system.

[0068] For example, based on the formula , the three-phase output voltage of the common coupling point is converted into voltage on the axis of the synchronous rotating coordinate system; wherein θ represents the rotation angle of the synchronous rotating coordinate system, u dpcc and u qpcc respectively represent the d-axis and q-axis components of the common coupling point voltage in the synchronous rotating coordinate system, u pcc_a , u pcc_b and u pcc_c represent the three-phase output voltage.

[0069] After obtaining the current sampling signal by using the current acquisition module to acquire the current value of the filter inductor of the actual circuit, before transmitting the current sampling signal to the current prediction module, the method further comprises:

[0070] Converting the three-phase output current of the filter inductor into current on the axis of the synchronous rotating coordinate system.

[0071] For example, based on the formula , the three-phase output current of the filter inductor is converted into current on the axis of the synchronous rotating coordinate system; wherein i Ld and i Lq respectively represent the d-axis and q-axis components of the three-phase output current in the synchronous rotating coordinate system, i La , i Lb and i Lc represent the three-phase output current.

[0072] Optionally, in the step S111, the voltage prediction signal is obtained by using the voltage prediction module according to the voltage sampling signal at the current time, comprising:

[0073] The voltage prediction module is used to obtain, according to the voltage sampling signal at the current time, a d-axis component u dpcc_p (k+1) and a q-axis component u qpcc_p (k+1) of the voltage prediction signal including the predicted voltage value of the next sampling time based on the formula ; wherein u dpcc (k) and u qpcc (k) represent the q-axis component and the d-axis component of the voltage value of the common coupling point in the synchronous rotating coordinate system at the current sampling time respectively; u dpcc (k-1) and u qpcc (k-1) represent the q-axis component and the d-axis component of the voltage value of the common coupling point in the synchronous rotating coordinate system at the last sampling time respectively.

[0074] Specifically, after the voltage prediction module 30 obtains the q-axis component u dpcc (k) and the d-axis component u qpcc (k) of the voltage value of the common coupling point in the current sampling period by using the voltage acquisition module 10, the q-axis component u dpcc (k-1) and the d-axis component u qpcc (k-1) of the voltage value of the common coupling point in the last sampling period are used to predict, based on the formula , the d-axis component u dpcc_p (k+1) and the q-axis component u qpcc_p (k+1) of the voltage prediction signal including the predicted voltage value of the common coupling point at the next sampling time.

[0075] Optionally, in the step S113, the current prediction module is used to construct a correction current according to the current current sampling signal at the current time and the current sampling signal predicted at the last time, and obtain the current prediction signal by using the correction current, the current sampling signal, the voltage sampling signal and the output signal of the delay module, including:

[0076] The current prediction module is used to obtain, based on the formula , the d-axis component i dp (k+1) and the q-axis component i qp (k+1) of the current prediction signal in the synchronous rotating coordinate system at the next sampling time; wherein, is a correction current expression, and X1 represents the proportional relationship between the actual current and the predicted current in the correction current.

[0077] Specifically, the correction current expression is After the current prediction module 40 obtains the correction current by using the actual current output at the current time and the predicted current which should be output at the current period, the correction current is used to correct the predicted current at the next time, that is, based on the formula , the d-axis component of the current prediction signal including the predicted current value at the next sampling time is obtained according to the corrected current, the current sampling signal, the voltage sampling signal and the signal output by the delay module dp (k+1) and the q-axis component i qp (k+1), wherein adjusting X1 can adjust the proportional relationship between the actual current and the predicted current, thereby performing steady-state error compensation.

[0078] Optionally, in the step S115, the voltage signal is obtained by the voltage generation module according to the current prediction signal, the voltage prediction signal and the compensation current instruction, comprising:

[0079] The voltage signal is obtained by the voltage generation module according to the current prediction signal, the voltage prediction signal and the compensation current instruction based on the formula ; wherein T s is a preset sampling period, ω0 is a rated angular frequency, u d (k+1) is the d-axis component of the voltage signal in the synchronous rotating coordinate system at the k+1 time, u q (k+1) is the q-axis component of the voltage signal in the synchronous rotating coordinate system at the k+1 time; u dpcc_p (k+1) is the d-axis component of the voltage prediction signal in the synchronous rotating coordinate system at the k+1 time, u qpcc_p (k+1) is the q-axis component of the voltage prediction signal in the synchronous rotating coordinate system at the k+1 time; i dref (k) is the d-axis component of the compensation current instruction in the synchronous rotating coordinate system at the k time, i qref (k) is the q-axis component of the compensation current instruction in the synchronous rotating coordinate system at the k time, i dref (k-1) is the d-axis component of the compensation current instruction in the k-1 period synchronous rotating coordinate system, i qref (k-1) is the q-axis component of the compensation current instruction in the k-1 period synchronous rotating coordinate system; i dp (k+1) is the d-axis component of the current prediction signal in the synchronous rotating coordinate system at the k+1 time, i qp (k+1) is the q-axis component of the current prediction signal in the synchronous rotating coordinate system at the k+1 time; B is a constant, B p is the parameter estimation value of B, B p -1 is the inverse of B p ; X2 represents the ratio of the current prediction signal to the compensation current instruction.

[0080] Specifically, the core control equation of the voltage generation module 50 is It can be known that the voltage signal output by the voltage generation module 50 is affected by the current prediction signal, the voltage prediction signal and the compensation current instruction, so after the voltage generation module 50 receives the current prediction signal, the voltage prediction signal and the compensation current instruction, the voltage signal of the next period is obtained based on the core control equation according to the above signals, then the voltage control signal is obtained by adding the error compensation signal, and the voltage control signal is output to the PWM generation module through the limiting module and the delay module to generate the control signal of the PWM to drive the actual circuit.

[0081] Optionally, the core control equation of the error compensation module 100 is:

[0082] ; wherein, T s is a preset sampling period, ω0 is a rated angular frequency, u d_cor (k+1) is the d-axis component of the error compensation signal, u q_cor (k+1) is the p-axis component of the error compensation signal, B is a constant, B p is the parameter estimation value of B, B p -1 represents the reciprocal of Bp, X3 is a compensation coefficient, and X3=X1+X2, i Ld (k) is the d-axis component of the current sampling signal in the synchronous rotating coordinate system at the k moment, i Lq (k) is the q-axis component of the current sampling signal in the synchronous rotating coordinate system at the k moment, i dp (k) is the d-axis component of the current prediction signal in the synchronous rotating coordinate system at the k moment, i qp (k) is the q-axis component of the current prediction signal in the synchronous rotating coordinate system at the k moment.

[0083] It should be noted that the above are only preferred embodiments of the present application and the technical principles applied. Those skilled in the art will understand that the present application is not limited to the specific embodiments described herein, and those skilled in the art can make various obvious changes, re-adjustments, mutual combinations and substitutions without departing from the scope of the present application. Therefore, although the present application has been described in more detail through the above embodiments, the present application is not limited to the above embodiments, and can include more other equivalent embodiments without departing from the concept of the present application, and the scope of the present application is determined by the scope of the appended claims.

Claims

1. A static error free APF current inner loop control system characterized by, The control module comprises a voltage acquisition module, a current acquisition module, a voltage prediction module, a current prediction module, a voltage generation module, a limiting module, a delay module, an error compensation module and a PWM generation module; the actual circuit comprises an APF inverter and a filter inductor, and the APF inverter and the filter inductor are connected in series and connected with a grid side; The input end of the voltage acquisition module is connected with a common coupling point of the actual circuit, the output end of the voltage acquisition module is connected with the input end of the voltage prediction module and the input end of the current prediction module respectively; the input end of the current acquisition module is connected with the filter inductor of the actual circuit, and the output end of the current acquisition module is connected with the input end of the current prediction module; the input end of the current prediction module is also connected with the output end of the delay module; the output end of the current prediction module is connected with the input end of the error compensation module and the input end of the voltage generation module respectively; the input of the voltage generation module is also used for receiving an external compensation current instruction and the output of the voltage prediction module; the error compensation module further comprises an input end for receiving an external compensation current instruction; the output of the voltage generation module is added with the output of the error compensation module, and then is connected with the limiting module, the delay module and the PWM generation module in sequence; the output end of the PWM generation module is connected with the APF inverter in the actual circuit as the output end of the control module; The voltage acquisition module is used for acquiring a voltage value of the common coupling point of the actual circuit, obtaining a voltage sampling signal and transmitting the voltage sampling signal to the voltage prediction module and the current prediction module; The voltage prediction module is used for obtaining a voltage prediction signal according to the voltage sampling signal at a current time and outputting the voltage prediction signal to the voltage generation module; The current acquisition module is used for acquiring a current value of the filter inductor of the actual circuit, obtaining a current sampling signal and transmitting the current sampling signal to the current prediction module; The current prediction module is used for constructing a correction current according to the current sampling signal at a current time and the current sampling signal at the current time predicted at a previous time, obtaining a current prediction signal by using the correction current, the current sampling signal, the voltage sampling signal and an output signal of the delay module, and outputting the current prediction signal to the voltage generation module and the error compensation module; The voltage generation module is used for obtaining a voltage signal according to the current prediction signal, the voltage prediction signal and the compensation current instruction; The error compensation module is used for obtaining an error compensation signal according to the compensation current instruction and the output of the current prediction module; The voltage signal and the error compensation signal are added to obtain a voltage control signal, and the voltage control signal is output to the PWM generation module through the limiting module and the delay module; The PWM generation module is used for converting the voltage control signal into a PWM wave signal to drive the APF inverter.

2. The control system of claim 1, wherein, The discrete control model of the actual circuit is: ， ； wherein T s is a preset sampling period, ω0 is a rated angular frequency, L1 is the filter inductance, R1 is the parasitic resistance in the actual circuit, A and B are constants, u d (k) is the d-axis component of the voltage signal in the synchronous rotating coordinate system at time k, u q (k) is the q-axis component of the voltage signal in the synchronous rotating coordinate system at time k; u dpcc (k) is the d-axis component of the voltage sampling signal in the synchronous rotating coordinate system at time k, u qpcc (k) is the q-axis component of the voltage sampling signal in the synchronous rotating coordinate system at time k; i Ld (k) is the d-axis component of the current sampling signal in the synchronous rotating coordinate system at time k, i Lq (k) is the q-axis component of the current sampling signal in the synchronous rotating coordinate system at time k; i Ld (k+1) is the d-axis component of the current sampling signal in the synchronous rotating coordinate system at time k+1, i Lq (k+1) is the q-axis component of the current sampling signal in the synchronous rotating coordinate system at time k+1.

3. The control system of claim 1, wherein, The core control equation of the voltage prediction module is: ； wherein, u dpcc_p (k+1) is the d-axis component of the voltage prediction signal in the synchronous rotating coordinate system at k+1 time, u qpcc_p (k+1) is the q-axis component of the voltage prediction signal in the synchronous rotating coordinate system at k+1 time, u dpcc (k) is the d-axis component of the voltage sampling signal in the synchronous rotating coordinate system at k time, u qpcc (k) is the q-axis component of the voltage sampling signal in the synchronous rotating coordinate system at k time, u dpcc (k-1) is the d-axis component of the voltage sampling signal in the synchronous rotating coordinate system at k-1 period, u qpcc (k-1) is the q-axis component of the voltage sampling signal in the synchronous rotating coordinate system at k-1 period.

4. The control system of claim 1, wherein, The core control equation of the current prediction module is: wherein T s is a preset sampling period, ω0 is a rated angular frequency, B is a constant, B p is a parameter estimation value of B, X1 represents a proportional relationship between an actual current and a predicted current in the correction current, i dp (k+1) is a d-axis component of the current prediction signal in a synchronous rotating coordinate system at k+1 moment, i qp (k+1) is a q-axis component of the current prediction signal in a synchronous rotating coordinate system at k+1 moment, i dp (k) is a d-axis component of the current prediction signal in a synchronous rotating coordinate system at k moment, i qp (k) is a q-axis component of the current prediction signal in a synchronous rotating coordinate system at k moment; u d (k) is a d-axis component of the voltage signal in a synchronous rotating coordinate system at k moment, u q (k) is a q-axis component of the voltage signal in a synchronous rotating coordinate system at k moment; u dpcc (k) is a d-axis component of the voltage sampling signal in a synchronous rotating coordinate system at k moment, u qpcc (k) is a q-axis component of the voltage sampling signal in a synchronous rotating coordinate system at k moment; i Ld (k) is a d-axis component of the current sampling signal in a synchronous rotating coordinate system at k moment, i Lq (k) is a q-axis component of the current sampling signal in a synchronous rotating coordinate system at k moment.

5. The control system of claim 1, wherein, The core control equation of the error compensation module is: ; wherein T s is a preset sampling period, ω0is a rated angular frequency, u d_cor (k+1) is a d-axis component of the error compensation signal, u q_cor (k+1) is a p-axis component of the error compensation signal, B is a constant, B p is an estimated value of B, B p -1 represents an inverse of Bp, X3is a compensation coefficient, i Ld (k) is a d-axis component of the current sampling signal in a synchronous rotating coordinate system at time k, i Lq (k) is a q-axis component of the current sampling signal in a synchronous rotating coordinate system at time k, i dp (k) is a d-axis component of the current prediction signal in a synchronous rotating coordinate system at time k, i qp (k) is a q-axis component of the current prediction signal in a synchronous rotating coordinate system at time k.

6. A static error-free APF current inner loop control method applied to the static error-free APF current inner loop control system of any one of claims 1-5, characterized in that, It comprises: The voltage acquisition module is used to acquire the voltage value of the actual circuit common coupling point to obtain a voltage sampling signal, and the voltage sampling signal is transmitted to the voltage prediction module and the current prediction module; The voltage prediction module is used to obtain a voltage prediction signal according to the voltage sampling signal at the current time, and the voltage prediction signal is output to the voltage generation module; The current acquisition module is used to acquire the current value of the filter inductance of the actual circuit to obtain a current sampling signal, and the current sampling signal is transmitted to the current prediction module; The current prediction module is used to form a correction current according to the current sampling signal at the current time and the current sampling signal at the current time predicted at the last time, and obtain a current prediction signal by using the correction current, the current sampling signal, the voltage sampling signal and the output signal of the delay module, and the current prediction signal is output to the voltage generation module and the error compensation module; The error compensation module is used to obtain an error compensation signal according to the compensation current instruction and the output of the current prediction module; The voltage generation module is used to obtain a voltage signal according to the current prediction signal, the voltage prediction signal and the compensation current instruction; the voltage signal and the error compensation signal are added to obtain a voltage control signal, and the voltage control signal is output to the PWM generation module through the limiting module and the delay module; The PWM generation module is used to convert the voltage control signal into a PWM wave signal to drive the APF inverter.

7. The control method according to claim 6, characterized by After the voltage acquisition module is used to acquire the voltage value of the actual circuit common coupling point to obtain a voltage sampling signal, before the voltage sampling signal is transmitted to the voltage prediction module and the current prediction module, it further comprises: Based on the formula the three-phase output voltage of the point of common coupling is converted into voltage in the synchronous rotating coordinate system; wherein θ represents the rotation angle of the synchronous rotating coordinate system, u dpcc and u qpcc respectively represent the d-axis and q-axis components of the point of common coupling voltage in the synchronous rotating coordinate system, u pcc_a , u pcc_b and u pcc_c represent the three-phase output voltage; After the current acquisition module is used to acquire the current value of the filter inductance of the actual circuit to obtain a current sampling signal, before the current sampling signal is transmitted to the current prediction module, it further comprises: Based on the formula The three-phase output currents of the filter inductor are converted into currents in a synchronous rotating coordinate system; wherein i Ld and i Lq respectively represent d-axis and q-axis components of the three-phase output currents in the synchronous rotating coordinate system, i La , i Lb and i Lc represent the three-phase output currents.

8. The control method according to claim 7, characterized by The voltage prediction module is used to obtain a voltage prediction signal according to the voltage sampling signal at the current time, comprising: The voltage prediction module is configured to obtain a voltage prediction signal based on the voltage sampling signal at the current time according to a formula , wherein uk+1 is a d-axis component of the voltage prediction signal in a synchronous rotating coordinate system at k+1 time, uk+1q is a q-axis component of the voltage prediction signal in the synchronous rotating coordinate system at k+1 time, uk is a d-axis component of the voltage sampling signal in the synchronous rotating coordinate system at k time, ukq is a q-axis component of the voltage sampling signal in the synchronous rotating coordinate system at k time, uk-1 is a d-axis component of the voltage sampling signal in the synchronous rotating coordinate system at k-1 cycle, and uk-1q is a q-axis component of the voltage sampling signal in the synchronous rotating coordinate system at k-1 cycle. dpcc_p qpcc_p dpcc qpcc dpcc qpcc , wherein uk+1 is a d-axis component of the voltage prediction signal in a synchronous rotating coordinate system at k+1 time, uk+1q is a q-axis component of the voltage prediction signal in the synchronous rotating coordinate system at k+1 time, uk is a d-axis component of the voltage sampling signal in the synchronous rotating coordinate system at k time, ukq is a q-axis component of the voltage sampling signal in the synchronous rotating coordinate system at k time, uk-1 is a d-axis component of the voltage sampling signal in the synchronous rotating coordinate system at k-1 cycle, and uk-1q is a q-axis component of the voltage sampling signal in the synchronous rotating coordinate system at k-1 cycle.​​​​​ 9. The control method according to claim 6, characterized by, The current prediction module is used to form a correction current according to the current sampling signal at the current time and the current sampling signal at the current time predicted at the last time, and obtain a current prediction signal by using the correction current, the current sampling signal, the voltage sampling signal and the output signal of the delay module, comprising: The current prediction module is used to obtain a d-axis component i (k+1) of the current prediction signal in a synchronous rotating coordinate system at a next sampling time based on a formula dp (k+1) and a q-axis component i qp (k+1) of the current prediction signal in the synchronous rotating coordinate system at the next sampling time; wherein, is the correction current expression, T s is a preset sampling period, ω0 is a rated angular frequency, B is a constant, B p is a parameter estimation value of B, X1 represents a proportional relationship between an actual current and a prediction current in the correction current, i dp (k+1) is the d-axis component of the current prediction signal in the synchronous rotating coordinate system at the k+1 sampling time, i qp (k+1) is the q-axis component of the current prediction signal in the synchronous rotating coordinate system at the k+1 sampling time, i dp (k) is the d-axis component of the current prediction signal in the synchronous rotating coordinate system at the k sampling time, i qp (k) is the q-axis component of the current prediction signal in the synchronous rotating coordinate system at the k sampling time; u d (k) is a d-axis component of the voltage signal in the synchronous rotating coordinate system at the k sampling time, u q (k) is a q-axis component of the voltage signal in the synchronous rotating coordinate system at the k sampling time; u dpcc (k) is a d-axis component of the voltage sampling signal in the synchronous rotating coordinate system at the k sampling time, u qpcc (k) is a q-axis component of the voltage sampling signal in the synchronous rotating coordinate system at the k sampling time; i Ld (k) is a d-axis component of the current sampling signal in the synchronous rotating coordinate system at the k sampling time, i Lq (k) is a q-axis component of the current sampling signal in the synchronous rotating coordinate system at the k sampling time.

10. The control method according to claim 6, characterized by The voltage generation module is used to obtain a voltage signal according to the current prediction signal, the voltage prediction signal and the compensation current instruction, comprising: The voltage generation module is used to generate a voltage signal according to the current prediction signal, the voltage prediction signal and the compensation current instruction based on the formula , wherein T s is a preset sampling period, ω0 is a rated angular frequency, u d (k+1) is a d-axis component of the voltage signal in a synchronous rotating coordinate system at k+1 moment, u q (k+1) is a q-axis component of the voltage signal in the synchronous rotating coordinate system at k+1 moment; u dpcc_p (k+1) is a d-axis component of the voltage prediction signal in the synchronous rotating coordinate system at k+1 moment, u qpcc_p (k+1) is a q-axis component of the voltage prediction signal in the synchronous rotating coordinate system at k+1 moment; i dref (k) is a d-axis component of the compensation current instruction in the synchronous rotating coordinate system at k moment, i qref (k) is a q-axis component of the compensation current instruction in the synchronous rotating coordinate system at k moment, i dref (k-1) is a d-axis component of the compensation current instruction in the synchronous rotating coordinate system at k-1 period, i qref (k-1) is a q-axis component of the compensation current instruction in the synchronous rotating coordinate system at k-1 period; i dp (k+1) is a d-axis component of the current prediction signal in the synchronous rotating coordinate system at k+1 moment, i qp (k+1) is a q-axis component of the current prediction signal in the synchronous rotating coordinate system at k+1 moment; B is a constant, B p is a parameter estimation value of B, B p -1 is an inverse of B p ; X2 represents a ratio of the current prediction signal to the compensation current instruction.

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