Non-delay dynamic tracking APF current inner loop control system and control method

Abstract

The embodiment of the invention provides a delay-free dynamic tracking APF current inner loop control system and 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, an amplitude limiting module, a time delay module and a PWM generation module; according to the technical scheme, the current value and the voltage value of the network side at the current moment are collected, the current value and the voltage value are used for prediction to obtain the prediction signal, the voltage control signal is obtained according to the prediction signal and the compensation current instruction, the APF controls the output voltage according to the voltage control signal, the APF inverter acts on an actual circuit, and therefore the current compensation effect is achieved. Therefore, 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.

Description

Technical Field

[0001] The embodiments of the present invention relate to the technical field of active power filtering, and in particular to an APF current inner loop control system and a control method for dynamic tracking without delay. Background Art

[0002] In new power systems, the penetration rate of power conversion equipment of power electronics is increasing, and higher-order harmonics are increasing accordingly. Although the traditional APF current control method is qualified in suppressing low-order harmonics of the power grid, the tracking and compensation of high-order harmonics requires the current control loop to have extremely high bandwidth and extremely small delay. The traditional APF current control method is difficult to achieve.

[0003] To this end, this patent discloses an APF control method with dynamic tracking without delay. The method first collects the APF output current and grid-side voltage signals of the current cycle; then expands the discrete control model of the APF to the next control cycle, and uses the model to predict the output current value of the next cycle; again, the expanded discrete control model is combined to obtain the equivalent output voltage value to be output in the next cycle; accordingly, the PWM modulation technology is used to generate the drive control signal of the power switch device of the APF. This solution can realize dynamic tracking of current instructions without delay and is easy to implement. Summary of the invention

[0004] The present invention provides an APF current inner loop control system and control method with non-delay dynamic tracking. The current value and voltage value on the grid side are collected at the current moment, and predictions are made using the current current value and voltage value respectively to obtain a prediction signal. A voltage control signal is obtained according to the prediction signal and a compensation current instruction. The APF controls the output voltage according to the voltage control signal and acts on the actual circuit to generate a compensation current. This greatly improves the dynamic performance of the existing APF current control algorithm, reduces the delay of the current control response, and realizes non-delay dynamic tracking of the current instruction.

[0005] In the first aspect, an embodiment of the present invention provides an APF current inner loop control system with dynamic tracking without delay, comprising 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 limit 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 to the grid side;

[0006] The input end of the voltage acquisition module is connected to the common coupling point of the actual circuit, and the output end of the voltage acquisition module is respectively connected to the input end of the voltage prediction module and the input end of the current prediction module; the current acquisition module acquires the current signal in the actual circuit and outputs it to the current prediction module; the input end of the current prediction module also includes the output of the delay module, and the output end of the current prediction module is connected to the input end of the voltage generation module; the input end of the voltage generation module also includes a compensation current instruction input end for receiving an external compensation current instruction; the output of the voltage generation module is added to the output of the voltage prediction module and used as the input of the limiting module; the output end of the limiting module is connected to the input end of the delay module; the output end of the delay module is connected to the input end of the PWM generation module, and the output end of the PWM generation module is connected to the APF inverter in the actual circuit as the output end of the control module;

[0007] The voltage acquisition module is used to acquire the voltage value of the common coupling point of the actual circuit, obtain a voltage sampling signal, and transmit the voltage sampling signal to the voltage prediction module;

[0008] The voltage prediction module is used to obtain a voltage prediction signal according to the voltage sampling signal at the current moment;

[0009] The current acquisition module is used to collect 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;

[0010] The current prediction module is used to obtain a current prediction signal according to 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;

[0011] The voltage generating module is used to obtain the output signal of the voltage generating module according to the current prediction signal and the compensation current instruction, and obtain the voltage control signal after adding it to the output of the voltage prediction module. The voltage control signal is output to the PWM generating module through the limiting module and the delay module; the PWM generating module is used to convert 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] Among them, Ts is the preset sampling period, ω0 is the 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 time k, and uq(k) is the q-axis component of the voltage control signal in the synchronous rotating coordinate system at time k; udpcc(k) is the d-axis component of the voltage sampling signal in the synchronous rotating coordinate system at time k, and uqpcc(k) is the q-axis component of the voltage sampling signal in the synchronous rotating coordinate system at time k; iLd(k) is the d-axis component of the current sampling signal in the synchronous rotating coordinate system at time k, and iLq(k) is the q-axis component of the current sampling signal in the synchronous rotating coordinate system at time k; iLd(k+1) is the d-axis component of the current sampling signal in the synchronous rotating coordinate system at time k+1, and iLq(k+1) is the q-axis component of the current sampling signal in the synchronous rotating coordinate system at time k+1.

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

[0015]

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

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

[0018]

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

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

[0021]

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

[0023] In a second aspect, the present invention further provides an APF inverter current inner loop control method with dynamic tracking without delay, which is applied to any of the APF inverter current inner loop control systems with dynamic tracking without delay as described in the first aspect of the present invention, comprising:

[0024] Using the voltage acquisition module to acquire the voltage value of the common coupling point of the actual circuit to obtain a voltage sampling signal, and transmitting the voltage sampling signal to the voltage prediction module;

[0025] Using the voltage prediction module to obtain a voltage prediction signal according to the voltage sampling signal at the current moment;

[0026] Using the current acquisition module to acquire 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;

[0027] Using the current prediction module to obtain a current prediction signal according to the current sampling signal, the voltage sampling signal and the output of the delay module at the current moment, and outputting the current prediction signal to the voltage generation module;

[0028] 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 instruction, and the output signal of the voltage generation module is added to 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 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 value of the common coupling point of the actual circuit is collected by the voltage collection module to obtain a voltage sampling signal, before the voltage sampling signal is transmitted to the voltage prediction module, the method further includes:

[0031] Based on the formula Convert the three-phase output voltage of the common coupling point into a voltage on a 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;

[0032] After the current value of the filter inductor of the actual circuit is collected by the current collection module to obtain a current sampling signal, before the current sampling signal is transmitted to the current prediction module, it also includes:

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

[0034] Optionally, obtaining a current prediction signal by using the current prediction module according to the current sampling signal, the voltage sampling signal and the output signal of the delay module at the current moment includes:

[0035] 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 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, using the voltage prediction module to obtain a voltage prediction signal according to the voltage sampling signal at the current moment includes:

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

[0038] Optionally, 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 signal to the output of the voltage prediction module to obtain the voltage control signal, including:

[0039] Using the voltage generation module, based on the formula According to the current prediction signal, the voltage prediction signal and the compensation current instruction, 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] An embodiment of the present invention provides an APF current inner loop control system and control method for dynamic tracking without delay, the system comprising a control module and an actual circuit; the control module comprising 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 to the grid side; the input end of the voltage acquisition module is connected to the common coupling point of the actual circuit, and the output end of the voltage acquisition module is respectively connected to the input end of the voltage prediction module and the input end of the current prediction module; the current acquisition module acquires the current signal in the actual circuit and outputs it to the current prediction module; the input end of the current prediction module also includes the output of the delay module, and the output end of the current prediction module is connected to the input end of the voltage generation module; the input end of the voltage generation module also includes a compensation current instruction input end for receiving an external compensation current instruction; the output of the voltage generation module is added to the output of the voltage prediction module as the input of the limiting module; the output end of the limiting module is connected to the input end of the delay module; the delay module The output end of the block is connected to the input end of the PWM generation module, and the output end of the PWM generation module is connected to the APF inverter in the actual circuit as the output end of the control module; the voltage acquisition module is used to collect 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 to obtain a voltage prediction signal according to the voltage sampling signal at the current moment; the current acquisition module is used to collect 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 according to 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 instruction, and obtain the voltage control signal after adding it to the output of the voltage prediction module, 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. The above technical solution collects the current value and voltage value on the grid side at the current moment, and uses the current current value and voltage value for prediction to obtain a prediction signal. A voltage control signal is obtained according to the prediction signal and the compensation current instruction. The APF controls the output voltage according to the voltage control signal, acts on the inverter in the actual circuit, and generates a compensation current, which greatly improves the dynamic performance of the existing APF current control algorithm, reduces the delay of the current control response, and realizes delay-free dynamic tracking of the current instruction. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Figure 1It is a structural schematic diagram of an APF current inner loop control system with dynamic tracking without delay provided by an embodiment of the present invention;

[0042] Figure 2 is a topological structure diagram of an actual circuit provided by an embodiment of the present invention;

[0043] Figure 3 It is a flow chart of an APF current inner loop control method with dynamic tracking without delay provided by an embodiment of the present invention;

[0044] Figure 4 It is a rendering of an APF current inner loop control method with dynamic tracking without delay provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0045] The present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments. It is to be understood that the specific embodiments described herein are only used to explain the present invention, rather than to limit the present invention. It should also be noted that, for ease of description, only parts related to the present invention, rather than all structures, are shown in the accompanying drawings.

[0046] The terms used in the embodiments of the present invention are only for the purpose of describing specific embodiments, and are not intended to limit the present invention. It should be noted that the directional words such as "upper", "lower", "left", "right" and the like described in the embodiments of the present invention are described at the angles shown in the accompanying drawings and should not be understood as limitations on the embodiments of the present invention. In addition, in the context, it is also necessary to understand that when it is mentioned that an element is 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", etc. are only used for descriptive purposes and do not represent any order, quantity or importance, but are only used to distinguish different components. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0047] The term “including” and its variations used in the present invention are open inclusions, that is, “including but not limited to.” The term “based on” means “based at least in part on.” The term “one embodiment” means “at least one embodiment.”

[0048] It should be noted that the concepts such as "first" and "second" mentioned in the present invention are only used to distinguish the corresponding contents, and are not used to limit the order or interdependence.

[0049] It should be noted that the modifications of "one" and "plurality" mentioned in the present invention are illustrative rather than restrictive, and those skilled in the art should understand that, unless otherwise clearly indicated in the context, it should be understood as "one or more".

[0050] Figure 1 1 is a schematic diagram of the structure of an APF current inner loop control system with dynamic tracking without delay provided by an embodiment of the present invention. Figure 2 is a topological structure diagram of an actual circuit provided by an embodiment of the present invention, refer 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 limit module 80, a delay module 90 and a PWM generation module 60; the actual circuit 70 includes an APF inverter 71 and a filter inductor 72, and the APF inverter 71 and the filter inductor 72 are connected in series in sequence and then connected to the 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 to the common coupling point of the actual circuit 70, and the output end of the voltage acquisition module 10 is respectively connected to the input end of the voltage prediction module 30 and the input end of the current prediction module 40; the current acquisition module 20 acquires the current signal in the actual circuit 70 and outputs it to the current prediction module 40; the input end of the current prediction module 40 also includes the output of the delay module 90, and the output end of the current prediction module 40 is connected to 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 an external compensation current instruction; the output of the voltage generation module 50 is added to the output of the voltage prediction module 30 and used as the input of the limiter module 80; the output end of the limiter module 80 is connected to the input end of the delay module 90; the output end of the delay module 90 is connected to the input end of the PWM generation module 60, and the output end of the PWM generation module 60 is connected to the APF inverter 71 in the actual circuit 70 as the output end of the control module; the voltage acquisition module 10 is used to collect the actual voltage The voltage value of the common coupling point of the circuit 70 is obtained to obtain a voltage sampling signal, and the voltage sampling signal is transmitted to the voltage prediction module 30; the voltage prediction module 30 is used to obtain a voltage prediction signal according to the voltage sampling signal at the current moment; the current acquisition module 20 is used to collect the current value of the filter inductor 72 of the actual circuit 70 to obtain a current sampling signal, and transmit the current sampling signal to the current prediction module 40; the current prediction module 40 is used to obtain a current prediction signal according to the current sampling signal, the voltage sampling signal and the output of the delay module 90 at the current moment, and output the current prediction signal to the voltage generation module 50; the voltage generation module 50 is used to obtain the output signal of the voltage generation module 50 according to the current prediction signal and the compensation current instruction, and obtain the voltage control signal after adding it to the output of the voltage prediction module 30, and 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 to convert the voltage control signal into a PWM wave signal to drive the APF inverter 71.

[0052] Figure 3 This is a flow chart of a non-delay dynamic tracking APF current inner loop control method provided by an embodiment of the present invention, and the following reference Figure 1-Figure 3 For an introduction to this method, see Figure 3 , the method comprising:

[0053] S110 , using a voltage acquisition module to acquire a voltage value of a common coupling point of an actual circuit, obtaining a voltage sampling signal, and transmitting the voltage sampling signal to a voltage prediction module.

[0054] Specifically, refer to Figure 1, the grid side will fluctuate, and when APF is applied to the grid, it is necessary to provide compensation current to the grid according to the fluctuation; illustratively, after determining the current size that needs to be compensated, APF needs to output a compensation current of corresponding size to compensate the grid side, and the grid side fluctuation is continuous and changing, so the compensation current also needs to change, so it is necessary to ensure that the current output by the actual circuit 70 can change in time, so it is necessary to first collect the voltage value of the grid side of the actual circuit 70 at a preset sampling period, and transmit the voltage value of the grid side to the voltage prediction module, so as to predict the voltage value that will change on the grid side at the next moment, so as to adjust the current output by the actual circuit according to the changed voltage.

[0055] S111 . Obtain a voltage prediction signal according to a voltage sampling signal at a current moment by using a voltage prediction module.

[0056] Specifically, after obtaining the voltage value of the grid side at the current moment, the voltage prediction module 30 predicts the predicted voltage value of the common coupling point PCC at the next acquisition moment using the voltage value of the common coupling point PCC at the current moment, and outputs it to the voltage generation module 50 .

[0057] S112, using the current acquisition module to acquire 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.

[0058] S113, using the current prediction module to obtain a current prediction signal according to 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.

[0059] Specifically, in order to make the current outputted to the grid side by the actual circuit 70 at the next moment more accurate, it is also necessary to use the current acquisition module 20 to collect the current value of the filter inductor 72 of the actual circuit to obtain a current sampling signal, and use the current sampling signal and the voltage sampling signal including the voltage value of the common coupling point PCC at the current moment, and the signal outputted by the delay module 90 to obtain a current prediction signal for the grid side current value at the next acquisition moment, and output the current prediction signal 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 it to 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 through the limiting module and the delay module.

[0061] Specifically, after the current prediction signal is output to the voltage generating module 50, the voltage generating module 50 obtains an output signal according to the current prediction signal and the compensation current instruction, and obtains a voltage control signal after adding it to the output of the voltage prediction module, and outputs it to the PWM generating module 60 to generate a PWM signal, thereby controlling the inverter 71 in the actual circuit 70 to output the current value corresponding to the compensation current instruction to the grid side under the drive of the PWM signal, thereby compensating the grid side current.

[0062] S115. Use the PWM generation module to convert the voltage control signal into a PWM wave signal 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 converted into a PWM wave signal by the PWM generation module 60 and then output to the actual circuit 70. The APF inverter 71 in the actual circuit 70 generates the current value at the next acquisition moment corresponding to the compensation current instruction according to the voltage control signal to the grid side, thereby compensating the grid side current, that is, the compensation current value required for the fluctuation at the next moment can be predicted and output.

[0064] Figure 4 This is a rendering of an APF current inner loop control method for dynamic tracking without delay provided by an embodiment of the present invention, referring to Figure 4 , A1 is the variation curve of the compensation current instruction corresponding to the compensation current that needs to be output to the power grid, A2 is the variation curve of the current output to the grid side of the actual circuit controlled according to the compensation current instruction under the APF current inner loop control method without delay dynamic tracking, and A3 is the variation curve of the current output to the grid side of the actual circuit controlled according to the compensation current instruction in the prior art. Figure 4 It can be seen that the dynamic response capability of the APF current inner loop control method with dynamic tracking without delay provided by the embodiment of the present invention is much higher than that of the prior art.

[0065] An embodiment of the present invention provides an APF current inner loop control system and control method for dynamic tracking without delay, the system comprising a control module and an actual circuit; the control module comprising 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 to the grid side; the input end of the voltage acquisition module is connected to the common coupling point of the actual circuit, and the output end of the voltage acquisition module is respectively connected to the input end of the voltage prediction module and the input end of the current prediction module; the current acquisition module acquires the current signal in the actual circuit and outputs it to the current prediction module; the input end of the current prediction module also includes the output of the delay module, and the output end of the current prediction module is connected to the input end of the voltage generation module; the input end of the voltage generation module also includes a compensation current instruction input end for receiving an external compensation current instruction; the output of the voltage generation module is added to the output of the voltage prediction module as the input of the limiting module; the output end of the limiting module is connected to the input end of the delay module; the delay module The output end of the block is connected to the input end of the PWM generation module, and the output end of the PWM generation module is connected to the APF inverter in the actual circuit as the output end of the control module; the voltage acquisition module is used to collect 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 to obtain a voltage prediction signal according to the voltage sampling signal at the current moment; the current acquisition module is used to collect 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 according to 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 instruction, and obtain the voltage control signal after adding it to the output of the voltage prediction module, 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. The above technical solution collects the current value and voltage value on the grid side at the current moment, and uses the current current value and voltage value for prediction to obtain a prediction signal. A voltage control signal is obtained according to the prediction signal and the compensation current instruction. The APF controls the output voltage according to the voltage control signal, acts on the inverter in the actual circuit, and generates a compensation current, which greatly improves the dynamic performance of the existing APF current control algorithm, reduces the delay of the current control response, and realizes delay-free dynamic tracking of the current instruction.

[0066] Optionally, in the above step S110, after the voltage sampling signal is obtained by using the voltage sampling module to collect the voltage value of the common coupling point of the actual circuit at a preset sampling period, before the voltage sampling signal is transmitted to the voltage prediction module, the following further comprises:

[0067] The three-phase output voltage at the common coupling point is converted into the voltage on the synchronous rotating coordinate system.

[0068] For example, based on the formula The three-phase output voltage at the common coupling point is converted into the voltage on 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] In the above step S112, after the current value of the filter inductor of the actual circuit is collected by the current collection module to obtain the current sampling signal, before the current sampling signal is transmitted to the current prediction module, it also includes:

[0070] The three-phase output current of the filter inductor is converted into the 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 the 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: Among them, udpcc_p(k+1) is the d-axis component of the voltage prediction signal in the synchronous rotating coordinate system at time k+1, uqpcc_p(k+1) is the q-axis component of the voltage prediction signal in the synchronous rotating coordinate system at time k+1, udpcc(k) is the d-axis component of the voltage sampling signal in the synchronous rotating coordinate system at time k, uqpcc(k) is the q-axis component of the voltage sampling signal in the synchronous rotating coordinate system at time k, udpcc(k-1) is the d-axis component of the voltage sampling signal in the synchronous rotating coordinate system of k-1 period, and uqpcc(k-1) is the q-axis component of the voltage sampling signal in the synchronous rotating coordinate system of k-1 period.

[0073] The above step S111, using the voltage prediction module to obtain a voltage prediction signal according to the voltage sampling signal at the current moment, includes:

[0074] Using the voltage prediction module, according to the voltage sampling signal at the current moment, based on the formula A voltage prediction signal is obtained.

[0075] Specifically, the voltage sampling signal reflects the voltage value of the common coupling point PCC at the current moment. 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 common coupling point PCC at the current acquisition moment, based on According to the d-axis component udpcc(k) and the q-axis component uqpcc(k) of the voltage value of the common coupling point PCC at the current acquisition moment, and the d-axis component udpcc(k-1) and the q-axis component uqpcc(k-1) of the voltage of the common coupling point PCC at the previous acquisition moment, 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 moment are obtained.

[0076] Optionally, the above step, using the current prediction module to obtain the current prediction signal according to the current sampling signal, the voltage sampling signal and the output signal of the delay module at the current moment, includes:

[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 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; wherein Ts is the preset sampling period, ω0 represents the rated angular frequency, k is the current acquisition moment, k+1 is the next acquisition moment, 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 to the output end of the delay module 90, and receives the d-axis component ud(k) and 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 to the output ends of the current acquisition module 20 and the voltage acquisition module 10, and receives the d-axis component id(k) and q-axis component iq(k) of the current sampling signal of the filter inductor 72 acquired by the current acquisition module 20 and the d-axis component udpcc(k) and q-axis component uqpcc(k) of the voltage value of the common coupling point PCC at the current acquisition time acquired by the voltage acquisition module 10, thereby 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 moment and the q-axis component iqp(k+1) of the current prediction signal in the synchronous rotating coordinate system at the next acquisition moment are obtained to predict the current of the actual circuit change at the next acquisition moment.

[0079] Optionally, 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 instruction, and the output signal of the voltage generation module is added to the output of the voltage prediction module to obtain the voltage control signal, including:

[0080] Using the voltage generation module, after obtaining the output signal of the voltage generation module according to the current prediction signal and the compensation current instruction, 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) of the voltage control signal at the next acquisition moment and the q-axis component u*q(k+1) of the voltage control signal at the next acquisition moment; wherein, idref(k) represents the d-axis component of the compensation current command at the current acquisition moment, iqref(k) represents the q-axis component of the compensation current command at the current acquisition moment, Ap represents the parameter estimation value of A, Bp represents the parameter estimation value of B, and Bp-1 represents the inverse of Bp; idp(k+1) represents the d-axis component of the current prediction signal at the next acquisition moment, iqp(k+1) represents the q-axis component of the current prediction signal at the next acquisition moment; udpcc_p(k+1) and uqpcc_p(k+1) are the d-axis component and q-axis component of the voltage prediction signal of the output voltage prediction module.

[0081] Specifically, the current prediction module 40 is used to predict 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 moment, and 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 instruction, and the voltage prediction module 30 is used to predict the d-axis component udpcc_p(k+1) and q-axis component iqp(k+1) of the voltage signal of the common coupling point at the next acquisition moment. 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) of the voltage control signal at the next acquisition moment and the q-axis component u*q(k+1) of the voltage control signal at the next acquisition moment, so that the inverter 71 in the actual circuit 70 outputs the corresponding current value to the grid side at the next acquisition moment according to the signal.

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

[0083] Wherein, Ts is the preset sampling period, ω0 is the 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 time k, and uq(k) is the q-axis component of the voltage control signal in the synchronous rotating coordinate system at time k; udpcc(k) is the d-axis component of the voltage sampling signal in the synchronous rotating coordinate system at time k, and uqpcc(k) is the q-axis component of the voltage sampling signal in the synchronous rotating coordinate system at time k; iLd(k) is the d-axis component of the current sampling signal in the synchronous rotating coordinate system at time k, and iLq(k) is the q-axis component of the current sampling signal in the synchronous rotating coordinate system at time k; iLd(k+1) is the d-axis component of the current sampling signal in the synchronous rotating coordinate system at time k+1, and iLq(k+1) is the q-axis component of the current sampling signal in the synchronous rotating coordinate system at time k+1.

[0084] Specifically, since the equivalent model of the actual circuit is In order to control the actual circuit, it needs to be converted into a discrete control model. The model reflects that the current value output by the actual circuit in the next cycle is related to the current value, voltage value and voltage control signal of the current cycle, so the current value can be predicted by the above parameters.

[0085] Note that the above are only preferred embodiments of the present invention and the technical principles used. Those skilled in the art will understand that the present invention is not limited to the specific embodiments described herein, and that various obvious changes, readjustments, combinations and substitutions can be made by those skilled in the art without departing from the scope of protection of the present invention. Therefore, although the present invention has been described in more detail through the above embodiments, the present invention is not limited to the above embodiments, and may include more other equivalent embodiments without departing from the concept of the present invention, and the scope of the present invention is determined by the scope of the appended claims.

Claims

1. A non-delay 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 limit module, a delay module and a PWM generation module; the actual circuit includes an APF inverter and a filter inductor, and the APF inverter and the filter inductor are connected in series and then connected to the grid side; The input end of the voltage acquisition module is connected to the common coupling point of the actual circuit, and the output end of the voltage acquisition module is respectively connected to the input end of the voltage prediction module and the input end of the current prediction module; the current acquisition module acquires the current signal in the actual circuit and outputs it to the current prediction module; the input end of the current prediction module also includes the output of the delay module, and the output end of the current prediction module is connected to the input end of the voltage generation module; the input end of the voltage generation module also includes a compensation current instruction input end for receiving an external compensation current instruction; the output of the voltage generation module is added to the output of the voltage prediction module and used as the input of the limiting module; the output end of the limiting module is connected to the input end of the delay module; the output end of the delay module is connected to the input end of the PWM generation module, and the output end of the PWM generation module is connected to the APF inverter in the actual circuit as the output end of the control module; The voltage acquisition module is used to acquire the voltage value of 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 according to the voltage sampling signal at the current moment; The current acquisition module is used to collect 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 according to 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 instruction, and obtain the voltage control signal after adding the output signal of the voltage prediction module, 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.

2. The control system according to claim 1, characterized in that: The discrete control model of the actual circuit is: Among them, Ts is the preset sampling period, ω0 is the 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 time k, and uq(k) is the q-axis component of the voltage control signal in the synchronous rotating coordinate system at time k; udpcc(k) is the d-axis component of the voltage sampling signal in the synchronous rotating coordinate system at time k, and uqpcc(k) is the q-axis component of the voltage sampling signal in the synchronous rotating coordinate system at time k; iLd(k) is the d-axis component of the current sampling signal in the synchronous rotating coordinate system at time k, and iLq(k) is the q-axis component of the current sampling signal in the synchronous rotating coordinate system at time k; iLd(k+1) is the d-axis component of the current sampling signal in the synchronous rotating coordinate system at time k+1, and iLq(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 according to claim 1, characterized in that: The core control equation of the voltage prediction module is: Among them, udpcc_p(k+1) is the d-axis component of the voltage prediction signal in the synchronous rotating coordinate system at time k+1, uqpcc_p(k+1) is the q-axis component of the voltage prediction signal in the synchronous rotating coordinate system at time k+1, udpcc(k) is the d-axis component of the voltage sampling signal in the synchronous rotating coordinate system at time k, uqpcc(k) is the q-axis component of the voltage sampling signal in the synchronous rotating coordinate system at time k, udpcc(k-1) is the d-axis component of the voltage sampling signal in the synchronous rotating coordinate system with a k-1 period, and uqpcc(k-1) is the q-axis component of the voltage sampling signal in the synchronous rotating coordinate system with a k-1 period.

4. The control system according to claim 1, characterized in that: The core control equation of the current prediction module is: Among them, idp(k+1) is the d-axis component of the current prediction signal in the synchronous rotating coordinate system at time k+1, iqp(k+1) is the q-axis component of the current prediction signal in the synchronous rotating coordinate system at time k+1, Ap is the parameter estimation value of A, Bp is the parameter estimation value of B, and Bp-1 is the reciprocal of Bp.

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

6. A non-delay dynamic tracking APF inverter current inner loop control method, applied to the non-delay dynamic tracking APF inverter current inner loop control system according to any one of claims 1 to 5, characterized in that: include: Using the voltage acquisition module to acquire the voltage value of the common coupling point of the actual circuit to obtain a voltage sampling signal, and transmitting the voltage sampling signal to the voltage prediction module; Using the voltage prediction module to obtain a voltage prediction signal according to the voltage sampling signal at the current moment; Using the current acquisition module to acquire 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; Using the current prediction module to obtain a current prediction signal according to the current sampling signal, the voltage sampling signal and the output of the delay module at the current moment, and outputting 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 instruction, and the output signal of the voltage generation module is added to 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 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 in that: After the voltage value of the common coupling point of the actual circuit is collected by the voltage collection module to obtain a voltage sampling signal, before the voltage sampling signal is transmitted to the voltage prediction module, the method further includes: Based on the formula Convert the three-phase output voltage of the common coupling point into a voltage on a 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; After the current value of the filter inductor of the actual circuit is collected by the current collection module to obtain a current sampling signal, before the current sampling signal is transmitted to the current prediction module, it also includes: Based on the formula The three-phase output current of the filter inductor is converted into a current on a synchronous rotating coordinate system; wherein iLd and iLq respectively represent the d-axis and q-axis components of the three-phase output current in the synchronous rotating coordinate system, and iLa, iLb and iLc represent the three-phase output current.

8. The control method according to claim 6, characterized in that: The current prediction module is used to obtain a current prediction signal according to the current sampling signal, the voltage sampling signal and the output signal of the delay module at the current moment, including: 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 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.

9. The control method according to claim 7, characterized in that: The voltage prediction module is used to obtain a voltage prediction signal according to the voltage sampling signal at the current moment, including: Using the voltage prediction module, according to the voltage sampling signal at the current moment, based on the formula A voltage prediction signal is obtained.

10. The control method according to claim 9, characterized in that: 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 instruction, and the output signal of the voltage generation module is added to the output of the voltage prediction module to obtain a voltage control signal, including: Using the voltage generation module, based on the formula According to the current prediction signal, the voltage prediction signal and the compensation current instruction, 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.

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