An APF current inner loop control system and control method with no delay dynamic tracking

Abstract

The application embodiment provides an APF current inner loop control system and control method of no-delay dynamic tracking, 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 and a PWM generation module; the above technical scheme, through collecting the current value and the voltage value of the grid side at the current time, respectively using the current value and the voltage value for prediction, obtaining the prediction signal, obtaining the voltage control signal according to the prediction signal and the compensation current instruction, the APF controls the output voltage according to the voltage control signal, and the APF inverter of the actual circuit is acted on, and then the compensation current change is controlled, the dynamic performance of the existing APF current control algorithm is greatly improved, the delay of the current control response is reduced, and the no-delay dynamic tracking of the current instruction is realized.

Description

TECHNICAL FIELD

[0001] The embodiment of the present application relates to the active power filter technology field, in particular to a no-delay dynamic tracking APF current inner loop control system and control method. BACKGROUND

[0002] In the new power system, the power electronic power conversion device penetration rate is increasing, and the higher order harmonics are also increasing. Although the traditional APF current control method is qualified in suppressing low-order harmonics of the power grid, for the tracking and compensation of high-order harmonics, the current control loop needs to have a very high bandwidth and a very small delay. The traditional APF current control method is difficult to achieve.

[0003] Therefore, the patent discloses a no-delay dynamic tracking APF control method. The method first acquires the APF output current and grid-side voltage signals of the current period; then extends the discrete control model of the APF to the next control period, and uses the model to predict the output current value of the next period; then combines the extended discrete control model to obtain the equivalent output voltage value that should be output in the next period; accordingly, the PWM modulation technology is used to generate the drive control signal of the power switch device of the APF. The scheme can realize no-delay dynamic tracking of the current command, and is easy to implement. SUMMARY

[0004] The present application provides a no-delay dynamic tracking APF current inner loop control system and control method, which acquires the current value and voltage value of the grid side at the current time, respectively uses the current value and voltage value for prediction to obtain a prediction signal, obtains a voltage control signal according to the prediction signal and a compensation current command, and controls the output voltage of the APF according to the voltage control signal, which acts on the actual circuit to generate a compensation current, greatly improves the dynamic performance of the existing APF current control algorithm, reduces the delay of the current control response, and realizes no-delay dynamic tracking of the current command.

[0005] In the first aspect, the embodiment of the present application provides a no-delay dynamic tracking APF current inner loop control system, which 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 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 the grid side.

[0006] 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 current acquisition module acquires the current signal in the actual circuit and outputs to the current prediction module; the input end of the current prediction module further comprises the output of the delay module, and the output end of the current prediction module is connected with the input end of the voltage generation module; the input end of the voltage generation module further comprises a compensation current instruction input end for receiving external compensation current instruction; the output of the voltage generation module is added with the output of the voltage prediction module to serve as the input of the limiting module; the output end of the limiting module is connected with the input end of the delay module; the output end of the delay module is connected with the input end of the PWM generation module, and the output end of the PWM generation module serves as the output end of the control module and is connected with the APF inverter in the actual circuit;

[0007] 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;

[0008] The voltage prediction module is used for obtaining a voltage prediction signal according to the voltage sampling signal at the current time;

[0009] The current acquisition module is used for acquiring 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;

[0010] The current prediction module is used for obtaining a current prediction signal according to the current sampling signal at the current time, the voltage sampling signal and the output of the delay module, and outputting the current prediction signal to the voltage generation module;

[0011] The voltage generation module is used for obtaining an output signal of the voltage generation module according to the current prediction signal and the compensation current instruction, and obtaining a voltage control signal after adding the output of the voltage prediction module, 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.

[0012] Optionally, the discrete control model of the actual circuit is:

[0013] Wherein, Ts 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, ud(k) is the d-axis component of the voltage control signal in the synchronous rotating coordinate system at k time, uq(k) is the q-axis component of the voltage control signal in the synchronous rotating coordinate system at k time; udpcc(k) is the d-axis component of the voltage sampling signal in the synchronous rotating coordinate system at k time, uqpcc(k) is the q-axis component of the voltage sampling signal in the synchronous rotating coordinate system at k time; iLd(k) is the d-axis component of the current sampling signal in the synchronous rotating coordinate system at k time, iLq(k) is the q-axis component of the current sampling signal in the synchronous rotating coordinate system at k time; iLd(k+1) is the d-axis component of the current sampling signal in the synchronous rotating coordinate system at k+1 time, iLq(k+1) is the q-axis component of the current sampling signal in the synchronous rotating coordinate system at k+1 time.

[0014] Optionally, the core control equation of the voltage prediction module is:

[0015]

[0016] Wherein, udpcc_p(k+1) is the d-axis component of the voltage prediction signal in the synchronous rotating coordinate system at k+1 time, uqpcc_p(k+1) is the q-axis component of the voltage prediction signal in the synchronous rotating coordinate system at k+1 time, udpcc(k) is the d-axis component of the voltage sampling signal in the synchronous rotating coordinate system at k time, uqpcc(k) is the q-axis component of the voltage sampling signal in the synchronous rotating coordinate system at k time, udpcc(k-1) is the d-axis component of the voltage sampling signal in the synchronous rotating coordinate system at k-1 period, uqpcc(k-1) is the q-axis component of the voltage sampling signal in the synchronous rotating coordinate system at k-1 period.

[0017] Optionally, the core control equation of the current prediction module is:

[0018]

[0019] Wherein, idp(k+1) is the d-axis component of the current prediction signal in the synchronous rotating coordinate system at k+1 time, iqp(k+1) is the q-axis component of the current prediction signal in the synchronous rotating coordinate system at k+1 time, Ap is the parameter estimation value of A, Bp is the parameter estimation value of B, Bp-1 is the reciprocal of Bp.

[0020] Optionally, the core control equation of the voltage generation module is:

[0021]

[0022] Wherein, u*d(k+1) is the d-axis component of the voltage control signal in the synchronous rotating coordinate system at k+1 time, u*q(k+1) is the q-axis component of the voltage control signal in the synchronous rotating coordinate system at k+1 time, idref(k) is the d-axis component of the compensation current command in the synchronous rotating coordinate system at k time, and iqref(k) is the q-axis component of the compensation current command in the synchronous rotating coordinate system at k time.

[0023] In a second aspect, the present application further provides a non-delay dynamic tracking APF inverter current inner loop control method, which is applied to the non-delay dynamic tracking APF inverter current inner loop control system of any one of the first aspect of the present application, and comprises the following steps:

[0024] The voltage acquisition module is used to acquire the voltage value of the actual circuit common coupling point, obtain a voltage sampling signal, and transmit the voltage sampling signal to the voltage prediction module.

[0025] The voltage prediction module is used to obtain a voltage prediction signal according to the voltage sampling signal at the current time.

[0026] The current acquisition module is used to acquire the current value of the filter inductance of the actual circuit, obtain a current sampling signal, and transmit the current sampling signal to the current prediction module.

[0027] The current prediction module is used to obtain a current prediction signal according to the current sampling signal at the current time, the voltage sampling signal and the output of the delay module, and output the current prediction signal to the voltage generation module.

[0028] The voltage generation module is used to obtain an output signal of the voltage generation module according to the current prediction signal and the compensation current command, add the output signal of the voltage generation module to the output of the voltage prediction module to obtain a voltage control signal, and output the voltage control signal to the PWM generation module through the limiting module and the delay module.

[0029] The PWM generation module is used to convert the voltage control signal into a PWM wave signal to drive the APF inverter.

[0030] Optionally, 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, the method further comprises the following steps:

[0031] Based on the formula The three-phase output voltage at the common coupling point is converted into a voltage on a synchronous rotating coordinate system; where θ represents the rotation angle of the synchronous rotating coordinate system, udpcc and uqpcc represent the d-axis and q-axis components of the voltage at the common coupling point in the synchronous rotating coordinate system, respectively, and upcc_a, upcc_b and upcc_c represent the three-phase output voltage.

[0032] After acquiring the current value of the filter inductor of the actual circuit using the current acquisition module to obtain a current sampling signal, and before transmitting the current sampling signal to the current prediction module, the method further includes:

[0033] Based on formula The three-phase output current of the filter inductor is converted into current in a synchronous rotating coordinate system; where iLd and iLq represent the d-axis and q-axis components of the three-phase output current in the synchronous rotating coordinate system, respectively, and iLa, iLb and iLc represent the three-phase output current.

[0034] Optionally, the current prediction module obtains a current prediction signal based on the current sampling signal, the voltage sampling signal, and the output signal of the delay module at the current moment, including:

[0035] Using the current prediction module, based on the formula Based on the current sampling signal, the voltage sampling signal, and the output signal of the delay module, the d-axis component idp(k+1) of the current prediction signal in the synchronous rotating coordinate system at the next moment and the q-axis component iqp(k+1) of the current prediction signal in the synchronous rotating coordinate system at the next moment are obtained.

[0036] Optionally, the voltage prediction module obtains a voltage prediction signal based on the voltage sampling signal at the current moment, including:

[0037] Using the voltage prediction module, based on the voltage sampling signal at the current moment, and based on the formula... The voltage prediction signal is obtained.

[0038] Optionally, the voltage generation module obtains its output signal based on the current prediction signal and the compensation current command, and adds it to the output of the voltage prediction module to obtain a voltage control signal, including:

[0039] Using the voltage generation module, based on the formula Based on the current prediction signal, the voltage prediction signal, and the compensation current command, the d-axis component u*d(k+1) of the voltage control signal and the q-axis component u*q(k+1) of the voltage control signal are obtained.

[0040] The embodiment of the application provides an APF current inner loop control system and a control method of non-delay dynamic tracking, 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 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 respectively; the current acquisition module acquires a current signal in the actual circuit and outputs to the current prediction module; the input end of the current prediction module further comprises an output of the delay module, and the output end of the current prediction module is connected with the input end of the voltage generation module; the input end of the voltage generation module further comprises a compensation current instruction input end for receiving an external compensation current instruction; the output of the voltage generation module and the output of the voltage prediction module are added to serve as the input of the limiting module; the output end of the limiting module is connected with the input end of the delay module; the output end of the delay module is connected with the input end of the PWM generation module, and 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 to obtain a voltage sampling signal and transmit the voltage sampling signal to the voltage prediction module; the voltage prediction module is used for obtaining a voltage prediction signal according to the voltage sampling signal at the current moment; the current acquisition module is used for acquiring the current value of the filter inductor of the actual circuit to obtain a current sampling signal and transmit the current sampling signal to the current prediction module; the current prediction module is used for obtaining a current prediction signal according to the current sampling signal at the current moment, the voltage sampling signal and the output of the delay module and outputting the current prediction signal to the voltage generation module; the voltage generation module is used for obtaining the output signal of the voltage generation module according to the current prediction signal and the compensation current instruction, adding the output signal of the voltage generation module and the output of the voltage prediction module 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; and the PWM generation module is used for converting the voltage control signal into a PWM wave signal to drive the APF inverter. Through the above technical scheme, the current value and the voltage value of the grid side at the current moment are acquired, the current value and the voltage value are respectively used for prediction to obtain prediction signals, the voltage control signal is obtained according to the prediction signals and the compensation current instruction, the APF controls the output voltage according to the voltage control signal, the output voltage acts on the inverter in the actual circuit to generate the compensation current, the dynamic performance of the existing APF current control algorithm is greatly improved, the delay of the current control response is reduced, and the non-delay dynamic tracking of the current instruction is realized. BRIEF DESCRIPTION OF DRAWINGS

[0041] Figure 1It is a structure schematic view of an APF current inner loop control system without time delay dynamic tracking provided by the embodiment of the present application.

[0042] Figure 2 It is a topology structure view of an actual circuit provided by the embodiment of the present application.

[0043] Figure 3 It is a flow schematic view of an APF current inner loop control method without time delay dynamic tracking provided by the embodiment of the present application.

[0044] Figure 4 It is an effect view of an APF current inner loop control method without time delay dynamic tracking provided by the embodiment of the present application. DETAILED DESCRIPTION

[0045] The present application will be further described below in conjunction with the accompanying drawings and embodiments. It can be understood that the specific embodiments described herein are only for the purpose of explaining the present application, but not for limiting the present application. In addition, it should be noted that, for the convenience of description, only the parts related to the present application are shown in the drawings, but not all the structures.

[0046] The terms used in the embodiments of the present application are only for the purpose of describing the specific embodiments, and are not intended to limit the present application. It should be noted that the orientation words such as "upper", "lower", "left", "right" and the like described in the embodiments of the present application are described with the angle shown in the drawings, and should not be understood as limiting the embodiments of the present application. In addition, it should be understood in the context that when referring to one element being formed "on" or "under" another element, it can be directly formed "on" or "under" another element, or 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 meaning of the above terms in the present application can be understood according to the specific circumstances.

[0047] The term "including" and its variants used in the present application are open inclusion, i.e. "including but not limited to". The term "based on" is "at least partially based on". The term "one embodiment" means "at least one embodiment".

[0048] 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 dependence relationship.

[0049] It should be noted that the modification of "one" or "multiple" mentioned in the present application is illustrative and not limiting, and those skilled in the art should understand that, unless otherwise explicitly indicated in the context, it should be understood as "one or more".

[0050] Figure 1 is a structure schematic diagram of an APF current inner loop control system with no delay dynamic tracking provided by an embodiment of the application, Figure 2 is a topology structure diagram of an actual circuit, for reference Figure 1 、 Figure 2 The system comprises a control module and an actual circuit; the control module comprises 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 and a PWM generation module 60; the actual circuit 70 comprises an APF inverter 71 and a filter inductor 72, the APF inverter 71 and the filter inductor 72 are connected in series in sequence and connected with a grid side Grid; R1 represents a parasitic resistance, PCC represents a common coupling point, Lline represents a line inductance and Rline represents a line parasitic resistance.

[0051] The input end of the voltage acquisition module 10 is connected with the common coupling point of the actual circuit 70, 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 current acquisition module 20 acquires the current signal in the actual circuit 70 and outputs to the current prediction module 40; the input end of the current prediction module 40 also includes the output of the delay module 90, the output end of the current prediction module 40 is connected with the input end of the voltage generation module 50; the input end of the voltage generation module 50 also includes a compensation current instruction input end for receiving external compensation current instruction; the output of the voltage generation module 50 is added with the output of the voltage prediction module 30 as the input of the limiting module 80; the output end of the limiting module 80 is connected with the input end of the delay module 90; the output end of the delay module 90 is connected with the input end of the PWM generation module 60, the output end of the PWM generation module 60 is connected with the APF inverter 71 in the actual circuit 70 as the output end of the control module; the voltage acquisition module 10 is used for acquiring the voltage value of the common coupling point of the actual circuit 70, obtaining the voltage sampling signal, and transmitting the voltage sampling signal to the voltage prediction module 30; the voltage prediction module 30 is used for obtaining the voltage prediction signal according to the voltage sampling signal at the current time; the current acquisition module 20 is used for acquiring the current value of the filter inductor 72 of the actual circuit 70 to obtain the current sampling signal and transmit the current sampling signal to the current prediction module 40; the current prediction module 40 is used for obtaining the current prediction signal according to the current sampling signal at the current time, the voltage sampling signal and the output of the delay module 90, and outputting the current prediction signal to the voltage generation module 50; the voltage generation module 50 is used for obtaining the output signal of the voltage generation module 50 according to the current prediction signal and the compensation current instruction, and obtaining the voltage control signal after adding the output of the voltage prediction module 30, the voltage control signal is output to the PWM generation module 60 through the limiting module 80 and the delay module 90; the PWM generation module 60 is used for converting the voltage control signal into the PWM wave signal to drive the APF inverter 71.

[0052] Figure 3 is a flow diagram of an APF current inner loop control method provided by the embodiment of the application, and the following refers to Figures 1-3 introduce the method, and refer to Figure 3 , the method comprises:

[0053] S110, the voltage value of the common coupling point of the actual circuit is acquired by using the voltage acquisition module, the voltage sampling signal is obtained, and the voltage sampling signal is transmitted to the voltage prediction module.

[0054] Specifically, refer to Figure 1, the grid side will fluctuate, and the APF needs to provide compensation current to the grid when applied to the grid; for example, after determining the size of the current that needs to be compensated, the APF needs to output a compensation current of the corresponding size to compensate the grid side, and the grid side fluctuation is continuous and variable, so the compensation current also needs to be variable, so the current output by the actual circuit 70 needs to be changed in time, so first the voltage value of the grid side of the actual circuit 70 needs to be collected at a preset sampling period, and the voltage value of the grid side is transmitted to the voltage prediction module, so as to predict the voltage value of the grid side at the next time, and adjust the current output by the actual circuit according to the changed voltage.

[0055] S111, using the voltage prediction module to obtain a voltage prediction signal according to the voltage sampling signal at the current time.

[0056] Specifically, after the voltage prediction module 30 obtains the voltage value of the grid side at the current time, the voltage value of the common coupling point PCC at the next collection time is predicted using the voltage value of the common coupling point PCC at the current time, and is output to the voltage generation module 50.

[0057] S112, using the current collection module to collect the current value of the filter inductance of the actual circuit to obtain a current sampling signal, and transmitting the current sampling signal to the current prediction module.

[0058] S113, using the current prediction module to obtain a current prediction signal according to the current sampling signal at the current time, the voltage sampling signal and the output of the delay module, and outputting the current prediction signal to the voltage generation module.

[0059] Specifically, in order to make the current output by the actual circuit 70 to the grid side at the next time more accurate, the current value of the filter inductance 72 of the actual circuit needs to be collected by the current collection module 20 to obtain a current sampling signal, and the current sampling signal and the voltage sampling signal including the voltage value of the common coupling point PCC at the current time, and the signal output by the delay module 90, are used to obtain a current prediction signal of the grid side current value at the next collection time, and the current prediction signal is output to the voltage generation module 50.

[0060] S114, using the voltage generation module to obtain the output signal of the voltage generation module according to the current prediction signal and the compensation current instruction, and adding the output of the voltage prediction module to obtain a voltage control signal, and the voltage control signal is output to the PWM generation module after passing through the limiting module and the delay module.

[0061] Specifically, after the current prediction signal is output to the voltage generation module 50, the voltage generation module 50 obtains an output signal according to the current prediction signal and the compensation current instruction, and adds the output signal to the output of the voltage prediction module to obtain a voltage control signal, which is output to the PWM generation module 60 to generate a PWM signal, so that the inverter 71 in the actual circuit 70 is driven by the PWM signal to output a current value corresponding to the compensation current instruction to the grid side, thereby compensating the grid side current.

[0062] S115, converting the voltage control signal into a PWM wave signal by using the PWM generation module to drive the APF inverter.

[0063] Specifically, the voltage control signal obtained according to the current prediction signal, the voltage prediction signal and the compensation current instruction is output to the actual circuit 70 after being converted into a PWM wave signal by the PWM generation module 60, and the APF inverter 71 in the actual circuit 70 generates a current value corresponding to the compensation current instruction to the grid side at the next sampling time according to the voltage control signal, thereby compensating the grid side current, that is, the compensation current value required by the fluctuation at the next time can be predicted and output.

[0064] Figure 4 is an effect diagram of the APF current inner loop control method without delay dynamic tracking provided by the embodiment of the application, referring to Figure 4 , A1 is a change curve of a compensation current instruction corresponding to a compensation current required to be output to the grid, A2 is a change curve of a current output to the grid by the actual circuit according to the compensation current instruction under the APF current inner loop control method without delay dynamic tracking, and A3 is a change curve of a current output to the grid by the actual circuit according to the compensation current instruction in the prior art. Figure 4 It can be known that the dynamic response capability of the APF current inner loop control method without delay dynamic tracking provided by the embodiment of the application is much higher than that of the prior art.

[0065] The embodiment of the application provides an APF current inner loop control system and a control method of non-delay dynamic tracking, 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 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 respectively; the current acquisition module acquires a current signal in the actual circuit and outputs to the current prediction module; the input end of the current prediction module further comprises an output of the delay module, and the output end of the current prediction module is connected with the input end of the voltage generation module; the input end of the voltage generation module further comprises a compensation current instruction input end for receiving an external compensation current instruction; the output of the voltage generation module and the output of the voltage prediction module are added to serve as the input of the limiting module; the output end of the limiting module is connected with the input end of the delay module; the output end of the delay module is connected with the input end of the PWM generation module, and 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 to obtain a voltage sampling signal and transmit the voltage sampling signal to the voltage prediction module; the voltage prediction module is used for obtaining a voltage prediction signal according to the voltage sampling signal at the current moment; the current acquisition module is used for acquiring the current value of the filter inductor of the actual circuit to obtain a current sampling signal and transmit the current sampling signal to the current prediction module; the current prediction module is used for obtaining a current prediction signal according to the current sampling signal at the current moment, the voltage sampling signal and the output of the delay module and outputting the current prediction signal to the voltage generation module; the voltage generation module is used for obtaining the output signal of the voltage generation module according to the current prediction signal and the compensation current instruction, adding the output signal of the voltage generation module and the output of the voltage prediction module 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; and the PWM generation module is used for converting the voltage control signal into a PWM wave signal to drive the APF inverter. Through the above technical scheme, the current value and the voltage value of the grid side at the current moment are acquired, the current value and the voltage value are used for prediction respectively to obtain prediction signals, the voltage control signal is obtained according to the prediction signals and the compensation current instruction, the APF controls the output voltage according to the voltage control signal, the output voltage acts on the inverter in the actual circuit to generate the compensation current, the dynamic performance of the existing APF current control algorithm is greatly improved, the delay of the current control response is reduced, and the non-delay dynamic tracking of the current instruction is realized.

[0066] Optionally, after the voltage value of the actual circuit common coupling point is collected by the voltage collection module in step S110 at a preset sampling period to obtain a voltage sampling signal, before the voltage sampling signal is transmitted to the voltage prediction module, the method further comprises:

[0067] The three-phase output voltage of the common coupling point is converted into voltage in 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 in the synchronous rotating coordinate system; wherein θ represents the rotation angle of the synchronous rotating coordinate system, udpcc and uqpcc represent the d-axis and q-axis components of the common coupling point voltage in the synchronous rotating coordinate system respectively, and upcc_a, upcc_b and upcc_c represent the three-phase output voltage.

[0069] After the current value of the filter inductor of the actual circuit is collected by the current collection module in step S112 to obtain a current sampling signal, before the current sampling signal is transmitted to the current prediction module, the method further comprises:

[0070] The three-phase output current of the filter inductor is converted into current in 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 in the synchronous rotating coordinate system; wherein iLd and iLq represent the d-axis and q-axis components of the three-phase output current in the synchronous rotating coordinate system respectively, and iLa, iLb and iLc represent the three-phase output current.

[0072] Optionally, the core control equation of the voltage prediction module is: Wherein udpcc_p(k+1) is the d-axis component of the voltage prediction signal in the synchronous rotating coordinate system at k+1 time, uqpcc_p(k+1) is the q-axis component of the voltage prediction signal in the synchronous rotating coordinate system at k+1 time, udpcc(k) is the d-axis component of the voltage sampling signal in the synchronous rotating coordinate system at k time, uqpcc(k) is the q-axis component of the voltage sampling signal in the synchronous rotating coordinate system at k time, udpcc(k-1) is the d-axis component of the voltage sampling signal in the synchronous rotating coordinate system at k-1 period, and uqpcc(k-1) is the q-axis component of the voltage sampling signal in the synchronous rotating coordinate system at k-1 period.

[0073] After the voltage prediction signal is obtained by the voltage prediction module according to the voltage sampling signal at the current time in step S111, the method further comprises:

[0074] The voltage prediction signal is obtained by the voltage prediction module according to the voltage sampling signal at the current time based on the formula .

[0075] Specifically, the voltage sampling signal reflects the voltage value of the point of common coupling PCC at the current time, and after the voltage acquisition module 10 acquires the d-axis component udpcc(k) and the q-axis component uqpcc(k) of the voltage value of the point of common coupling PCC at the current acquisition time, based on According to the d-axis component udpcc(k) and the q-axis component uqpcc(k) of the voltage value of the point of common coupling PCC at the current acquisition time, and the d-axis component udpcc(k-1) and the q-axis component uqpcc(k-1) of the voltage of the point of common coupling PCC at the previous acquisition time, the d-axis component udpcc_p(k+1) and the q-axis component uqpcc_p(k+1) of the voltage prediction signal for predicting the voltage value at the next time are obtained.

[0076] Optionally, the above step, using the current prediction module, obtains the current prediction signal according to the current sampling signal, the voltage sampling signal and the output signal of the delay module, comprising:

[0077] Using the current prediction module, based on the formula According to the current sampling signal, the voltage sampling signal and the output signal of the delay module, the d-axis component idp(k+1) of the current prediction signal in the synchronous rotating coordinate system at the next time and the q-axis component iqp(k+1) of the current prediction signal in the synchronous rotating coordinate system at the next time are obtained; wherein Ts is a preset sampling period, ω0 represents a rated angular frequency, k is the current acquisition time, k+1 is the next acquisition time, A and B are both constants, Ap represents the parameter estimation value of A, and Bp represents the parameter estimation value of B.

[0078] Specifically, the input end of the current prediction module 40 is connected with the output end of the delay module 90, and receives the d-axis component ud(k) and the q-axis component uq(k) of the voltage control signal at the current sampling time K output by the delay module 90. The input end of the current prediction module 40 is also connected with the output end of the current acquisition module 20 and the voltage acquisition module 10, and receives the d-axis component id(k) and the q-axis component iq(k) of the current sampling signal of the filter inductance 72 acquired by the current acquisition module 20, and the d-axis component udpcc(k) and the q-axis component uqpcc(k) of the voltage value of the point of common coupling PCC at the current acquisition time acquired by the voltage acquisition module 10, so as to obtain the d-axis component idp(k+1) and the q-axis component iqp(k+1) of the current prediction signal in the synchronous rotating coordinate system at the next acquisition time based on the formula According to the current sampling signal, the voltage sampling signal and the output signal of the delay module, the d-axis component idp(k+1) of the current prediction signal in the synchronous rotating coordinate system at the next acquisition time and the q-axis component iqp(k+1) of the current prediction signal in the synchronous rotating coordinate system at the next acquisition time are obtained, so as to predict the current changed by the actual circuit at the next acquisition time.

[0079] Optionally, the voltage generation module obtains its output signal based on the current prediction signal and the compensation current command, and adds it to the output of the voltage prediction module to obtain a voltage control signal, including:

[0080] Using the voltage generation module, after obtaining the output signal of the voltage generation module based on the current prediction signal and the compensation current command, the formula is then applied. The output signal of the voltage generation module is added to the output signal of the voltage prediction module to obtain the d-axis component u*d(k+1) and the q-axis component u*q(k+1) of the voltage control signal at the next acquisition time. Among them, idref(k) represents the d-axis component of the compensation current command at the current acquisition time, iqref(k) represents the q-axis component of the compensation current command at the current acquisition time, Ap represents the parameter estimate of A, Bp represents the parameter estimate of B, and Bp-1 represents the reciprocal of Bp; idp(k+1) represents the d-axis component of the current prediction signal at the next acquisition time, iqp(k+1) represents the q-axis component of the current prediction signal at the next acquisition time; udpcc_p(k+1) and uqpcc_p(k+1) are the d-axis and q-axis components of the voltage prediction signal of the output voltage prediction module.

[0081] Specifically, the current prediction module 40 predicts the d-axis component idp(k+1) and q-axis component iqp(k+1) of the current signal of the filter inductor in the actual circuit at the next acquisition time. The voltage generation module obtains its output signal based on the current prediction signal and the compensation current command. Then, the voltage prediction module 30 predicts the d-axis component udpcc_p(k+1) and q-axis component iqp(k+1) of the voltage signal at the common coupling point at the next acquisition time. Finally, based on the formula... The output signal of the voltage generation module is added to the output of the voltage prediction module to obtain the d-axis component u*d(k+1) and the q-axis component u*q(k+1) of the voltage control signal at the next acquisition time. This allows the inverter 71 in the actual circuit 70 to output the corresponding current value to the grid side at the next acquisition time based on the signal.

[0082] Optionally, the discrete control model of the actual circuit is as follows:

[0083] Wherein, Ts is a preset sampling period, ω0 is a rated angular frequency, L1 is a filter inductance, R1 is a parasitic resistance in an actual circuit, A and B are constants, ud(k) is a d-axis component of a voltage control signal in a synchronous rotating coordinate system at k moment, uq(k) is a q-axis component of the voltage control signal in the synchronous rotating coordinate system at k moment; udpcc(k) is a d-axis component of a voltage sampling signal in the synchronous rotating coordinate system at k moment, uqpcc(k) is a q-axis component of the voltage sampling signal in the synchronous rotating coordinate system at k moment; iLd(k) is a d-axis component of a current sampling signal in the synchronous rotating coordinate system at k moment, iLq(k) is a q-axis component of the current sampling signal in the synchronous rotating coordinate system at k moment; iLd(k+1) is a d-axis component of the current sampling signal in the synchronous rotating coordinate system at k+1 moment, iLq(k+1) is a q-axis component of the current sampling signal in the synchronous rotating coordinate system at k+1 moment.

[0084] Specifically, since an equivalent model of an actual circuit is In order to control the actual circuit, it is necessary to convert it into a discrete control model, The model reflects that a current value of a next period output of the actual circuit is related to a current value, a voltage value and a voltage control signal of a current period, and thus the current value can be predicted through the above parameters.

[0085] It is to be noted that the above only describes the preferred embodiments of the present application and the applied technical principles. 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 replacements without departing from the protection scope of the present application. Therefore, although the present application has been described in detail through the above embodiments, the present application is not limited to the above embodiments, and more other equivalent embodiments can be included without departing from the concept of the present application, and the scope of the present application is determined by the appended claims.

Claims

1. A time-delay-free dynamic tracking APF current inner loop control system, characterized in that, It includes a control module and an actual circuit; the control module includes 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, and a PWM generation module; the actual circuit includes an APF inverter and a filter inductor, the APF inverter and the filter inductor being connected in series and then connected to the grid side; The input terminal of the voltage acquisition module is connected to the common coupling point of the actual circuit, and the output terminal of the voltage acquisition module is connected to the input terminals of the voltage prediction module and the current prediction module, respectively. The current acquisition module acquires the current signal in the actual circuit and outputs it to the current prediction module. The input terminal of the current prediction module also includes the output of the delay module, and the output terminal of the current prediction module is connected to the input terminal of the voltage generation module. The input terminal of the voltage generation module also includes a compensation current command input terminal for receiving external compensation current commands. The output of the voltage generation module and the output of the voltage prediction module are added together and used as the input of the limiting module. The output terminal of the limiting module is connected to the input terminal of the delay module. The output terminal of the delay module is connected to the input terminal of the PWM generation module, and the output terminal of the PWM generation module is used as the output terminal of the control module and connected to the APF inverter in the actual circuit. The voltage acquisition module is used to acquire the voltage value at the common coupling point of the actual circuit, obtain a voltage sampling signal, and transmit the voltage sampling signal to the voltage prediction module; The voltage prediction module is used to obtain a voltage prediction signal based on the voltage sampling signal at the current moment; 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, and transmit the current sampling signal to the current prediction module. The current prediction module is used to obtain a current prediction signal based on the current sampling signal, the voltage sampling signal and the output of the delay module at the current moment, and output the current prediction signal to the voltage generation module; The voltage generation module is used to obtain the output signal of the voltage generation module according to the current prediction signal and the compensation current command, and add it to the output of the voltage prediction module to obtain the voltage control signal. The voltage control signal is output to the PWM generation module after passing 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.

2. The control system according to claim 1, characterized in that, The discrete control model of the actual circuit is as follows: , Among them, T s The preset sampling period is ω0, the rated angular frequency is L1, the filter inductance is R1, the parasitic resistance in the actual circuit is A and B, and u is a constant. d (k) represents the d-axis component of the voltage control signal in the synchronously rotating coordinate system at time k, u q (k) represents the q-axis component of the voltage control signal in the synchronously rotating coordinate system at time k; u dpcc (k) represents the d-axis component of the voltage sampling signal in the synchronously rotating coordinate system at time k, u qpcc (k) represents the q-axis component of the voltage sampling signal in the synchronously rotating coordinate system at time k; i Ld (k) represents the d-axis component of the current sampling signal in the synchronously rotating coordinate system at time k, i Lq (k) represents the q-axis component of the current sampling signal in the synchronously rotating coordinate system at time k; i Ld (k+1) represents the d-axis component of the current sampling signal in the synchronously rotating coordinate system at time k+1, i Lq (k+1) represents the q-axis component of the current sampling signal in the synchronously rotating coordinate system at time k+1.

3. The control system according to claim 1, characterized in that, The core control equation of the voltage prediction module is: ； Among them, u dpcc_p (k+1) represents the d-axis component of the voltage prediction signal in the synchronously rotating coordinate system at time k+1, u qpcc_p (k+1) represents the q-axis component of the voltage prediction signal in the synchronously rotating coordinate system at time k+1, u dpcc (k) represents the d-axis component of the voltage sampling signal in the synchronously rotating coordinate system at time k, u qpcc (k) represents the q-axis component of the voltage sampling signal in the synchronously rotating coordinate system at time k, u dpcc (k-1) represents the d-axis component of the voltage sampling signal in a k-1 periodically rotating coordinate system, u qpcc (k-1) represents the q-axis component of the voltage sampling signal in the k-1 periodic rotating coordinate system.

4. The control system according to claim 1, characterized in that, The core control equation of the current prediction module is: ； Where, i dp (k+1) represents the d-axis component of the current prediction signal in the synchronously rotating coordinate system at time k+1, i qp (k+1) represents the q-axis component of the current prediction signal in the synchronously rotating coordinate system at time k+1, where A and B are constants. p Here are the parameter estimates for A, and for B... p T represents the parameter estimate of B. s The preset sampling period is ω0, where ω is the rated angular frequency, and i Ld (k) represents the d-axis component of the current sampling signal in the synchronously rotating coordinate system at time k, i Lq (k) represents the q-axis component of the current sampling signal in the synchronously rotating coordinate system at time k, u d (k) represents the d-axis component of the voltage control signal in the synchronously rotating coordinate system at time k, u q (k) represents the q-axis component of the voltage control signal in the synchronously rotating coordinate system at time k, u dpcc (k) represents the d-axis component of the voltage sampling signal in the synchronously rotating coordinate system at time k, u qpcc (k) represents the q-axis component of the voltage sampling signal in the synchronously rotating coordinate system at time k.

5. The control system according to claim 1, characterized in that, The core control equation of the voltage generation module is: ； Among them, u d * (k+1) represents the d-axis component of the voltage control signal in the synchronously rotating coordinate system at time k+1, u q * (k+1) represents the q-axis component of the voltage control signal in the synchronously rotating coordinate system at time k+1, where A and B are constants. p Here are the parameter estimates for A, and for B... p These are the parameter estimates for B, B p -1 T represents the reciprocal of Bp. s The preset sampling period is ω0, where ω is the rated angular frequency, and i dref (k) represents the d-axis component of the compensation current command in the synchronously rotating coordinate system at time k, i qref (k) represents the q-axis component of the compensation current command in the synchronously rotating coordinate system at time k, i dp (k+1) represents the d-axis component of the current prediction signal in the synchronously rotating coordinate system at time k+1, i qp (k+1) represents the q-axis component of the current prediction signal in the synchronously rotating coordinate system at time k+1, u dpcc_p (k+1) represents the d-axis component of the voltage sampling signal in the synchronously rotating coordinate system at time k+1, u qpcc_p (k+1) represents the q-axis component of the voltage sampling signal in the synchronously rotating coordinate system at time k+1.

6. A delay-free dynamic tracking APF inverter current inner loop control method, applied to the delay-free dynamic tracking APF inverter current inner loop control system according to any one of claims 1-5, characterized in that, include: The voltage acquisition module acquires the voltage value at the common coupling point of the actual circuit to obtain a voltage sampling signal, and then transmits the voltage sampling signal to the voltage prediction module. The voltage prediction module uses the voltage sampling signal at the current moment to obtain a voltage prediction signal; 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, and the current sampling signal is transmitted to the current prediction module. The current prediction module uses the current sampling signal, the voltage sampling signal, and the output of the delay module at the current moment to obtain a current prediction signal, and then outputs the current prediction signal to the voltage generation module. The voltage generation module obtains its output signal based on the current prediction signal and the compensation current command, and adds it to the output of the voltage prediction module to obtain a voltage control signal. The voltage control signal is then output to the PWM generation module after passing through the limiting module and the delay module. The voltage control signal is converted into a PWM wave signal using the PWM generation module to drive the APF inverter.

7. The control method according to claim 6, characterized in that, After acquiring the voltage value at the common coupling point of the actual circuit using the voltage acquisition module and obtaining the voltage sampling signal, before transmitting the voltage sampling signal to the voltage prediction module, the method further includes: Based on formula The three-phase output voltage at the common coupling point is converted into a voltage in a synchronous rotating coordinate system; where θ represents the rotation angle of the synchronous rotating coordinate system, and u dpcc and u qpcc Representing the d-axis and q-axis components of the voltage at the common coupling point in the synchronous rotating coordinate system, u pcc_a u pcc_b and u pcc_c This indicates the three-phase output voltage; After acquiring the current value of the filter inductor of the actual circuit using the current acquisition module to obtain a current sampling signal, and before transmitting the current sampling signal to the current prediction module, the method further includes: Based on formula The three-phase output current of the filter inductor is converted into current in a synchronous rotating coordinate system; where i Ld and i Lq Let i represent the d-axis and q-axis components of the three-phase output current in the synchronous rotating coordinate system, respectively. La i Lb and i Lc This indicates the three-phase output current.

8. The control method according to claim 6, characterized in that, The current prediction module uses the current sampling signal, the voltage sampling signal, and the output signal of the delay module at the current moment to obtain a current prediction signal, including: Using the current prediction module, based on the formula Based on the current sampling signal, the voltage sampling signal, and the output signal of the delay module, the d-axis component i of the current prediction signal in the synchronous rotating coordinate system at the next moment is obtained. dp The q-axis component of the current prediction signal in the synchronously rotating coordinate system at (k+1) and the next time step is i qp (k+1); where T s The preset sampling period is ω0, the rated angular frequency is ω0, and A and B are constants. p Here are the parameter estimates for A, and for B... p These are the parameter estimates of B, i Ld (k) represents the d-axis component of the current sampling signal in the synchronously rotating coordinate system at time k, i Lq (k) represents the q-axis component of the current sampling signal in the synchronously rotating coordinate system at time k, u d (k) represents the d-axis component of the voltage control signal in the synchronously rotating coordinate system at time k, u q (k) represents the q-axis component of the voltage control signal in the synchronously rotating coordinate system at time k, u dpcc (k) represents the d-axis component of the voltage sampling signal in the synchronously rotating coordinate system at time k, u qpcc (k) represents the q-axis component of the voltage sampling signal in the synchronously rotating coordinate system at time k.

9. The control method according to claim 7, characterized in that, The voltage prediction module uses the voltage sampling signal at the current moment to obtain a voltage prediction signal, including: Using the voltage prediction module, based on the voltage sampling signal at the current moment, and based on the formula... The voltage prediction signal is obtained; where u dpcc_p (k+1) represents the d-axis component of the voltage sampling signal in the synchronously rotating coordinate system at time k+1, u qpcc_p (k+1) represents the q-axis component of the voltage sampling signal in the synchronously rotating coordinate system at time k+1, u dpcc (k) represents the d-axis component of the voltage sampling signal in the synchronously rotating coordinate system at time k, u qpcc (k) represents the q-axis component of the voltage sampling signal in the synchronously rotating coordinate system at time k, u dpcc (k-1) represents the d-axis component of the voltage sampling signal in the synchronously rotating coordinate system at time k-1, u qpcc (k-1) represents the q-axis component of the voltage sampling signal in the synchronously rotating coordinate system at time k-1.

10. The control method according to claim 9, characterized in that, The voltage generation module generates an output signal based on the current prediction signal and the compensation current command, and adds this output signal to the voltage prediction module to obtain a voltage control signal, including: Using the voltage generation module, based on the formula Based on the current prediction signal, the voltage prediction signal, and the compensation current command, the d-axis component u of the voltage control signal is obtained. d * (k+1) and the q-axis component u of the voltage control signal q * (k+1); where u d * (k+1) represents the d-axis component of the voltage control signal in the synchronously rotating coordinate system at time k+1, u q * (k+1) represents the q-axis component of the voltage control signal in the synchronously rotating coordinate system at time k+1, i dref (k) represents the d-axis component of the compensation current command in the synchronously rotating coordinate system at time k, i qref (k) represents the q-axis component of the compensation current command in the synchronously rotating coordinate system at time k, T s The preset sampling period is ω0, the rated angular frequency is A. p Here are the parameter estimates for A, and for B... p These are the parameter estimates for B, B p -1 i represents the reciprocal of Bp. dp (k+1) represents the d-axis component of the current prediction signal in the synchronously rotating coordinate system at time k+1, i qp (k+1) represents the q-axis component of the current prediction signal in the synchronously rotating coordinate system at time k+1.

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