An APFC control method and system, a PFC control method and system

Abstract

The application discloses an APFC control method and system and a PFC control method and system, and the APFC control method comprises the following steps: acquiring a d-axis current setting value Idref and a d-axis current actual value Idfw; performing PI operation on the difference between the d-axis current setting value Idref and the d-axis current actual value Idfw to obtain a proportional coefficient; calculating the sum of the proportional coefficient and a set voltage modulation coefficient to obtain a correction coefficient; calculating the product of the correction coefficient and an input voltage peak value to obtain a bus voltage demand value Vref; limiting the amplitude of the bus voltage demand value Vref to obtain a bus voltage setting value Vref_out; when the load changes, the input voltage and the input current will change, and the bus voltage setting value Vref_out will also change, and the actual bus voltage will dynamically change along with the bus voltage setting value; the problem that the bus voltage cannot be dynamically adjusted is solved, the loss of a power device can be effectively reduced, and the driving efficiency of a variable frequency module is improved.

Description

Technical Field

[0001] This invention belongs to the field of circuit technology, specifically, it relates to an APFC control method, an APFC control system, a PFC control method, and a PFC control system. Background Technology

[0002] With the continuous improvement of modern permanent magnet material technology, permanent magnet synchronous motors have been widely used in products across various industries. Although permanent magnet synchronous motors are small in size and have high performance, they are complex nonlinear systems that require advanced drive technology.

[0003] Currently, single-phase power supply inverter drives in air conditioners mainly use sensorless FOC vector control algorithm and PFC control algorithm. PFC control circuit can effectively improve the output efficiency of inverter module and increase bus voltage.

[0004] However, the bus voltage raised by the PFC circuit is currently a fixed value and cannot be dynamically adjusted according to the load condition. When the load is small, the bus voltage is still very high. When the bus voltage is high, the switching losses of the power devices will also increase, affecting the output efficiency of the frequency converter module.

[0005] Current PFC control schemes generally follow the principle of activating PFC control based on the input current state, thereby raising the bus voltage to a fixed value. This control strategy is not flexible enough. Under low load conditions, the power device losses are too high. If the PFC circuit is activated too late, the system input power factor will be too low, resulting in even lower module output efficiency. Summary of the Invention

[0006] This invention provides an APFC control method that solves the problem of the inability to dynamically adjust the bus voltage.

[0007] To achieve the above-mentioned technical objectives, the present invention adopts the following technical solution:

[0008] An APFC control method, comprising:

[0009] Obtain the d-axis current setpoint Idref and the actual d-axis current Idfw;

[0010] The difference between the d-axis current setting value Idref and the actual d-axis current value Idfw is used to perform PI calculation to obtain the proportional coefficient, where 0 < proportional coefficient < 1.

[0011] The correction factor is obtained by summing the proportional coefficient and the set voltage modulation coefficient.

[0012] The bus voltage demand value Vref is obtained by multiplying the correction factor by the peak value of the input voltage.

[0013] The bus voltage demand value Vref is limited, and the bus voltage set value Vref_out is obtained after limiting.

[0014] In some embodiments of this application, the d-axis current setting value Idref = motor demagnetizing current × setting percentage.

[0015] In some embodiments of this application, the calculation process for the peak input voltage is as follows:

[0016] Obtain the live wire voltage and the neutral wire voltage;

[0017] Calculate Vac = |live wire voltage - neutral wire voltage| / 2;

[0018] Perform a low-pass filter on Vac to obtain Vac_ave;

[0019] Calculate the peak input voltage Vpeak = Vac_ave × 1.57.

[0020] A PFC control method, comprising:

[0021] The bus voltage setpoint Vref_out is obtained according to the APFC control method described above;

[0022] The difference between the bus voltage setting value Vref_out and the actual bus voltage value Vdc is used for PI calculation to obtain the current setting value;

[0023] The duty cycle is obtained by performing a PI calculation on the difference between the current set value and the actual input current value.

[0024] A square wave signal is generated based on the duty cycle and output to the power transistor of the PFC circuit.

[0025] In some embodiments of this application, the current setting value obtained by PI calculation is multiplied by the current phase of the input voltage to obtain the phase-adjusted current setting value. Then, the difference between the phase-adjusted current setting value and the actual value of the input current is subjected to PI calculation to obtain the duty cycle.

[0026] An APFC control system includes:

[0027] The current acquisition module is used to acquire the d-axis current setpoint Idref and the actual d-axis current value Idfw.

[0028] The first PI controller is used to perform PI calculation on the difference between the d-axis current setpoint Idref and the actual d-axis current value Idfw to obtain the proportional coefficient, where 0 < proportional coefficient < 1.

[0029] The addition module is used to calculate the sum of the proportional coefficient and the set voltage modulation coefficient to obtain the correction coefficient;

[0030] The first multiplication module is used to calculate the product of the correction coefficient and the peak value of the input voltage to obtain the bus voltage demand value Vref;

[0031] The limiting module is used to limit the bus voltage demand value Vref, and the bus voltage setting value Vref_out is obtained after limiting.

[0032] In some embodiments of this application, the current acquisition module includes:

[0033] The d-axis current setpoint calculation unit is used to calculate the d-axis current setpoint Idref = motor demagnetizing current × setpoint percentage;

[0034] The d-axis current actual value calculation unit is used to calculate the actual value of the d-axis current Idfw.

[0035] In some embodiments of this application, the APFC control system further includes an input voltage peak calculation module; the input voltage peak calculation module includes:

[0036] The input voltage sampling unit is used to acquire the live wire voltage and the neutral wire voltage;

[0037] The calculation unit is used to calculate Vac = |live wire voltage - neutral wire voltage| / 2;

[0038] A low-pass filter is used to perform low-pass filtering on Vac to obtain Vac_ave;

[0039] The multiplication unit is used to calculate the peak input voltage Vpeak = Vac_ave × 1.57.

[0040] A PFC control system, comprising:

[0041] The APFC control system is used to calculate the bus voltage setpoint Vref_out;

[0042] The second PI controller is used to perform PI calculation on the difference between the bus voltage setpoint Vref_out and the actual bus voltage Vdc to obtain the current setpoint.

[0043] The third PI controller is used to perform PI calculation on the difference between the current set value and the actual value of the input current to obtain the duty cycle.

[0044] The driving circuit is used to generate a square wave signal according to the duty cycle and output it to the power transistor of the PFC circuit.

[0045] In some embodiments of this application, the PFC control system further includes:

[0046] The second multiplication module is used to multiply the current setting value output by the second PI controller by the current phase of the input voltage to obtain the phase-adjusted current setting value.

[0047] The third PI controller is used to perform PI calculation on the difference between the phase-adjusted current setpoint and the actual input current value to obtain the duty cycle.

[0048] Compared with existing technologies, the advantages and positive effects of this invention are as follows: The APFC control method, APFC control system, PFC control method, and PFC control system of this invention obtain the d-axis current setpoint Idref and the actual d-axis current value Idfw; perform PI calculation on the difference between the d-axis current setpoint Idref and the actual d-axis current value Idfw to obtain the proportional coefficient; calculate the sum of the proportional coefficient and the set voltage modulation coefficient to obtain the correction coefficient; calculate the product of the correction coefficient and the peak value of the input voltage to obtain the bus voltage demand value Vref; limit the bus voltage demand value Vref to obtain the bus voltage setpoint Vref_out; when the load changes, the input voltage and input current will change, the bus voltage setpoint Vref_out will also change, and the actual bus voltage Vdc will dynamically change with the bus voltage setpoint Vref_out; this solves the problem that the bus voltage cannot be dynamically adjusted, effectively reducing the loss of power devices and improving the driving efficiency of the frequency converter module.

[0049] Other features and advantages of the present invention will become clearer after reading the detailed description of the embodiments of the present invention in conjunction with the accompanying drawings. Attached Figure Description

[0050] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0051] Figure 1 This is a flowchart of an embodiment of the APFC control method proposed in this invention;

[0052] Figure 2 This is a circuit block diagram of an embodiment of the APFC control system proposed in this invention;

[0053] Figure 3 This is a flowchart of an embodiment of the PFC control method proposed in this invention;

[0054] Figure 4 This is a circuit block diagram of an embodiment of the PFC control system proposed in this invention. Detailed Implementation

[0055] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this application.

[0056] In the description of this application, it should be understood that the terms "center", "upper", "lower", "front", "rear", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application.

[0057] In the description of this application, it should be understood that the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this application, unless otherwise stated, "multiple" means two or more.

[0058] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection between two components. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0059] To address the current problem of the inability to dynamically adjust bus voltage, this invention proposes an APFC control method, an APFC control system, a PFC control method, and a PFC control system. These solutions resolve the issue of dynamic bus voltage adjustment, effectively reduce power device losses, and improve the drive efficiency of the frequency converter module. The APFC control method, APFC control system, PFC control method, and PFC control system of this invention will be described in detail below with reference to the accompanying drawings.

[0060] Example 1

[0061] This embodiment proposes an APFC control method, which mainly includes the following steps, see below. Figure 1 As shown below. (Combined with...) Figure 1 Flowcharts and Figure 2 The APFC control block diagram is explained in detail.

[0062] Step S11: Obtain the d-axis current setting value Idref and the actual d-axis current value Idfw.

[0063] In some embodiments of this application, the d-axis current setting value Idref = motor demagnetizing current × setting percentage.

[0064] The d-axis current setting value Idref is calculated directly based on the percentage of the motor demagnetizing current. The calculation is relatively simple and can yield a relatively small d-axis current setting value.

[0065] In this embodiment, the percentage is set to 2.5%.

[0066] The three-phase currents Iu, Iv, and Iw of the motor are collected, and after Clark and Park transformations, the actual d-axis current value Idfw can be obtained.

[0067] Step S12: Perform a PI calculation on the difference between the d-axis current setting value Idref and the actual d-axis current value Idfw to obtain the proportional coefficient, where 0 < proportional coefficient < 1.

[0068] The proportional coefficient calculated using PI needs to be subject to high or low limits, ensuring that the proportional coefficient is greater than 0 and less than 1.

[0069] Step S13: Calculate the sum of the proportional coefficient and the set voltage modulation coefficient Radio to obtain the correction coefficient.

[0070] Correction factor = proportional factor + set voltage modulation factor (Radio).

[0071] In this embodiment, the voltage modulation coefficient is typically set to 0.95.

[0072] Step S14: Calculate the product of the correction factor and the peak value of the input voltage to obtain the bus voltage demand value Vref.

[0073] Bus voltage demand value Vref = correction factor × peak input voltage Vpeak.

[0074] In some embodiments of this application, the calculation process for the input voltage peak value Vpeak is as follows:

[0075] (14-1) Obtain the live wire voltage UL and the neutral wire voltage UN.

[0076] Input voltage = live wire voltage UL - neutral wire voltage UN.

[0077] (14-2) Calculate Vac = |live wire voltage - neutral wire voltage| / 2.

[0078] (14-3) Perform a low-pass filter on Vac to obtain Vac_ave.

[0079] (14-4) Calculate the peak input voltage Vpeak = Vac_ave × 1.57.

[0080] Through the calculation process described in (14-1) to (14-4) above, the peak input voltage Vpeak can be calculated quickly and accurately.

[0081] Step S15: Limit the bus voltage demand value Vref, and obtain the bus voltage setpoint Vref_out after limiting.

[0082] The bus voltage demand value Vref is limited by the voltage limit Vref_max, and the bus voltage set value Vref_out obtained after limiting is less than or equal to the voltage limit Vref_max.

[0083] When the bus voltage demand value Vref ≤ the voltage limit value Vref_max, the bus voltage setting value Vref_out = the bus voltage demand value Vref;

[0084] When the bus voltage demand value Vref > the voltage limit value Vref_max, the bus voltage setting value Vref_out = the voltage limit value Vref_max.

[0085] By limiting the bus voltage demand value Vref, the bus voltage setting value Vref_out is obtained, which prevents the bus voltage setting value from being too large and thus avoids the bus voltage from rising without limit.

[0086] Since the d-axis current setting value Idref is very small, basically zero, when not in the field weakening state, the voltage setting value Vref_out calculated by the above method is the minimum voltage value that is just right for not entering the field weakening control.

[0087] When the load changes, the input voltage and input current will change, and the calculated bus voltage setpoint Vref_out will also change, thus realizing the dynamic change of the bus voltage setpoint Vref_out. The actual bus voltage Vdc will dynamically follow the bus voltage setpoint Vref_out, thus realizing the dynamic change of the actual bus voltage Vdc.

[0088] The APFC control method in this embodiment obtains the d-axis current setpoint Idref and the actual d-axis current Idfw; performs a PI calculation on the difference between the d-axis current setpoint Idref and the actual d-axis current Idfw to obtain the proportional coefficient; calculates the sum of the proportional coefficient and the set voltage modulation coefficient to obtain the correction coefficient; calculates the product of the correction coefficient and the peak value of the input voltage to obtain the bus voltage demand value Vref; limits the bus voltage demand value Vref, and obtains the bus voltage setpoint Vref_out after limiting; when the load changes, the input voltage and input current will change, and the bus voltage setpoint Vref_out will also change, and the actual bus voltage Vdc will dynamically change with the bus voltage setpoint Vref_out; thus solving the problem that the bus voltage cannot be dynamically adjusted.

[0089] The APFC control method in this embodiment can dynamically adjust the bus voltage setpoint Vref_out according to the load status, thereby dynamically adjusting the bus voltage, which can effectively reduce the loss of power devices and improve the driving efficiency of the frequency converter module.

[0090] The APFC control method in this embodiment mainly adjusts the bus voltage value dynamically according to the current load status, so that the bus voltage is maintained at the minimum level required by the current load, ensuring that the field weakening control is not entered under medium and low load, reducing the switching loss of power devices and improving the output efficiency of the frequency converter module.

[0091] The APFC control method of this application, such as Figure 1 , Figure 2 As shown, by limiting the magnetic field current and sampling the input voltage, the minimum required bus voltage under the current load is determined, i.e., the bus voltage setpoint Vref_out.

[0092] Example 2

[0093] Based on the APFC control method of Embodiment 1, this Embodiment 2 proposes an APFC control system, including a current acquisition module, a first PI controller, an adder module, a first multiplier module, a limiting module, etc. (See [link to documentation]). Figure 2 As shown.

[0094] The current acquisition module is used to acquire the d-axis current setpoint Idref and the actual d-axis current value Idfw.

[0095] The first PI controller is used to perform PI calculation on the difference between the d-axis current setpoint Idref and the actual d-axis current value Idfw to obtain the proportional coefficient, where 0 < proportional coefficient < 1.

[0096] The addition module is used to calculate the sum of the proportional coefficient and the set voltage modulation coefficient to obtain the correction coefficient.

[0097] The first multiplication module is used to calculate the product of the correction coefficient and the peak value of the input voltage to obtain the bus voltage demand value Vref.

[0098] The limiting module is used to limit the bus voltage demand value Vref, resulting in the bus voltage setpoint Vref_out. The bus voltage demand value Vref is limited by the voltage limit Vref_max, and the resulting bus voltage setpoint Vref_out is less than or equal to the voltage limit Vref_max.

[0099] In some embodiments of this application, the current acquisition module includes a d-axis current setpoint calculation unit and a d-axis current actual value calculation unit.

[0100] The d-axis current setting value calculation unit is used to calculate the d-axis current setting value Idref = motor demagnetizing current × setting percentage.

[0101] The d-axis current actual value calculation unit is used to calculate the actual value of the d-axis current Idfw.

[0102] In some embodiments of this application, the APFC control system further includes an input voltage peak calculation module; the input voltage peak calculation module includes:

[0103] The input voltage sampling unit is used to acquire the live wire voltage and the neutral wire voltage;

[0104] The calculation unit is used to calculate Vac = |live wire voltage - neutral wire voltage| / 2;

[0105] A low-pass filter is used to perform low-pass filtering on Vac to obtain Vac_ave;

[0106] The multiplication unit is used to calculate the peak input voltage Vpeak = Vac_ave × 1.57.

[0107] The specific working process of the APFC control system has been described in detail in the APFC control method of Example 1, and will not be repeated here.

[0108] The APFC control system in this embodiment acquires the d-axis current setpoint Idref and the actual d-axis current Idfw; performs a PI calculation on the difference between the d-axis current setpoint Idref and the actual d-axis current Idfw to obtain the proportional coefficient; calculates the sum of the proportional coefficient and the set voltage modulation coefficient to obtain the correction coefficient; calculates the product of the correction coefficient and the peak input voltage to obtain the bus voltage demand value Vref; limits the bus voltage demand value Vref, and obtains the bus voltage setpoint Vref_out after limiting; when the load changes, the input voltage and input current will change, and the bus voltage setpoint Vref_out will also change, and the actual bus voltage Vdc will dynamically change with the bus voltage setpoint Vref_out; this solves the problem of the bus voltage not being able to be dynamically adjusted; it can effectively reduce the loss of power devices and improve the driving efficiency of the frequency converter module.

[0109] Example 3

[0110] Based on the design of the APFC control method in Embodiment 1, Embodiment 3 proposes a PFC control method, which mainly includes the following steps, see below. Figure 3 , Figure 4 As shown.

[0111] Step S21: Obtain the bus voltage setpoint Vref_out according to the APFC control method in Example 1.

[0112] The APFC control method has been described in detail in Example 1 and will not be repeated here.

[0113] Step S22: Perform a PI calculation on the difference between the bus voltage setting value Vref_out and the actual bus voltage value Vdc to obtain the current setting value.

[0114] Step S23: Perform a PI calculation on the difference between the current set value and the actual input current value to obtain the duty cycle.

[0115] Step S24: Generate a square wave signal according to the duty cycle and output it to the power transistor of the PFC circuit to control the on / off state of the power transistor.

[0116] Figure 4 The upper part is a schematic diagram of the rectifier hardware driven by the frequency converter. By acquiring the input voltage, the required voltage setpoint Vref_out of the bus is obtained through the APFC control method in Example 1. The voltage setpoint Vref_out and the current actual bus voltage value Vdc are used to perform PI calculation to obtain the current setpoint. Then, the current setpoint is used to perform PI calculation with the actual current value to obtain the duty cycle. A square wave signal is generated according to the duty cycle to control the on and off of the power transistor, thereby ensuring that the PFC circuit realizes the power correction function and dynamically adjusts the bus voltage rise value.

[0117] The PFC control method in this embodiment obtains the bus voltage setpoint Vref_out; performs a PI calculation on the difference between the bus voltage setpoint Vref_out and the actual bus voltage Vdc to obtain the current setpoint; performs a PI calculation on the difference between the current setpoint and the actual input current to obtain the duty cycle; generates a square wave signal based on the duty cycle and outputs it to the power transistor of the PFC circuit to control the switching of the power transistor; when the load changes, the input voltage and input current change, and the bus voltage setpoint Vref_out also changes. The actual bus voltage Vdc changes dynamically with the bus voltage setpoint Vref_out, solving the problem of the bus voltage not being able to be dynamically adjusted; it can effectively reduce the loss of power devices and improve the driving efficiency of the frequency converter module.

[0118] In some embodiments of this application, the current setting value obtained by PI calculation is multiplied by the current phase of the input voltage to obtain the phase-adjusted current setting value. Then, the difference between the phase-adjusted current setting value and the actual value of the input current is subjected to PI calculation to obtain the duty cycle.

[0119] That is, after step S22 and before step S23, the current setting value is adjusted using the current phase of the input voltage so that the current phase follows the voltage phase, thereby ensuring the normal operation of the entire PFC circuit.

[0120] The current phase of the input voltage refers to the current phase of the live wire voltage.

[0121] The PFC control method in this embodiment can dynamically adjust the APFC output according to the load status, ensuring that the bus voltage value changes with the load and is maintained at the minimum voltage value that does not enter the field weakening control state.

[0122] The PFC control method in this embodiment calculates the minimum output voltage of APFC control based on the input current and input voltage, combined with the minimum voltage of field weakening control. When the load changes, the input current and voltage also change, thereby changing the minimum output voltage of APFC control and realizing the dynamic change of bus voltage.

[0123] The PFC control method in this embodiment dynamically adjusts the bus voltage according to the load status. By detecting the current load status, the bus voltage is maintained at the minimum value just before entering the field weakening stage. This can effectively solve the problem of excessive power device losses caused by a fixed bus voltage when the load is not large.

[0124] Example 4

[0125] Based on the designs of Embodiments 1, 2, and 3, this Embodiment 4 proposes a PFC control system, including an APFC control system, a second PI controller, a third PI controller, a drive circuit, etc. (See [link to documentation]). Figure 4 As shown.

[0126] The APFC control system, also known as the APFC control system in Example 2, is used to calculate the bus voltage setpoint Vref_out.

[0127] The second PI controller is used to perform PI calculation on the difference between the bus voltage setpoint Vref_out and the actual bus voltage value Vdc to obtain the current setpoint.

[0128] The third PI controller is used to perform PI calculations on the difference between the current setpoint and the actual input current value to obtain the duty cycle.

[0129] The driver circuit generates a square wave signal based on the duty cycle and outputs the square wave signal to the power transistor in the PFC circuit to control the switching of the power transistor. For example, Figure 4 The driver circuit (MOSFET Driver) outputs a square wave signal to the MOSFET to drive its operation.

[0130] Furthermore, the MOSFET Driver driving circuit also generates an OC singel signal to trigger overcurrent protection and prevent overcurrent from damaging the device.

[0131] In some embodiments of this application, the PFC control system further includes a second multiplication module.

[0132] The second multiplication module is used to multiply the current setting value output by the second PI controller by the current phase of the input voltage to obtain the phase-adjusted current setting value.

[0133] The third PI controller is used to perform PI calculations on the difference between the phase-adjusted current setpoint and the actual input current value to obtain the duty cycle.

[0134] The specific working process of the PFC control system has been described in detail in the PFC control method of Example 3, and will not be repeated here.

[0135] The PFC control system in this embodiment obtains the bus voltage setpoint Vref_out; performs a PI calculation on the difference between the bus voltage setpoint Vref_out and the actual bus voltage Vdc to obtain the current setpoint; performs a PI calculation on the difference between the current setpoint and the actual input current to obtain the duty cycle; generates a square wave signal based on the duty cycle and outputs it to the power transistor of the PFC circuit to control the switching of the power transistor; when the load changes, the input voltage and input current change, and the bus voltage setpoint Vref_out also changes. The actual bus voltage Vdc dynamically changes with the bus voltage setpoint Vref_out, solving the problem of the bus voltage not being able to be dynamically adjusted; it can effectively reduce the loss of power devices and improve the driving efficiency of the frequency converter module.

[0136] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. An APFC control method, characterized by: The method comprises the following steps: obtaining a d-axis current setting value Idref and a d-axis current actual value Idfw; performing PI operation on the difference between the d-axis current setting value Idref and the d-axis current actual value Idfw to obtain a proportional coefficient, 0 < proportional coefficient < 1; calculating the sum of the proportional coefficient and a set voltage modulation coefficient to obtain a correction coefficient; calculating the product of the correction coefficient and an input voltage peak value to obtain a bus voltage demand value Vref; limiting the bus voltage demand value Vref to obtain a bus voltage setting value Vref_out.

2. The APFC control method according to claim 1, wherein the d-axis current setting value Idref = motor demagnetization current × set percentage. The calculation process of the input voltage peak value is as follows:

3. The APFC control method according to claim 1, characterized in that: obtaining a live line voltage and a neutral line voltage; calculating Vac = | live line voltage - neutral line voltage | / 2; performing low-pass filtering on Vac to obtain Vac_ave; calculating an input voltage peak value Vpeak = Vac_ave × 1.

57. The method comprises the following steps:

4. A PFC control method characterized by: obtaining a bus voltage setting value Vref_out by the APFC control method according to any one of claims 1 to 3; performing PI operation on the difference between the bus voltage setting value Vref_out and a bus voltage actual value Vdc to obtain a current setting value; performing PI operation on the difference between the current setting value and an input current actual value to obtain a duty cycle; generating a square wave signal according to the duty cycle and outputting the square wave signal to a power tube of a PFC circuit.

5. The PFC control method according to claim 4, wherein the current setting value obtained by PI operation is multiplied by a current phase of an input voltage to obtain a phase-adjusted current setting value, and then PI operation is performed on the difference between the phase-adjusted current setting value and the input current actual value to obtain the duty cycle. The method comprises the following steps: a current obtaining module, configured to obtain a d-axis current setting value Idref and a d-axis current actual value Idfw; 6. An APFC control system characterized by: a first PI controller, configured to perform PI operation on the difference between the d-axis current setting value Idref and the d-axis current actual value Idfw to obtain a proportional coefficient, 0 < proportional coefficient < 1; an addition module, configured to calculate the sum of the proportional coefficient and a set voltage modulation coefficient to obtain a correction coefficient; a first multiplication module, configured to calculate the product of the correction coefficient and an input voltage peak value to obtain a bus voltage demand value Vref; a limiting module, configured to limit the bus voltage demand value Vref to obtain a bus voltage setting value Vref_out. The current obtaining module comprises: a d-axis current setting value calculation unit, configured to calculate a d-axis current setting value Idref = motor demagnetization current × set percentage; 7. The APFC control system of claim 6, wherein: a d-axis current actual value calculation unit, configured to calculate a d-axis current actual value Idfw. The APFC control system further comprises an input voltage peak value calculation module; the input voltage peak value calculation module comprises: an input voltage sampling unit, configured to obtain a live line voltage and a neutral line voltage; 8. The APFC control system of claim 6, wherein: a calculation unit, configured to calculate Vac = | live line voltage - neutral line voltage | / 2; a low-pass filter, configured to perform low-pass filtering on Vac to obtain Vac_ave; ​ ​ A multiplication unit is configured to calculate an input voltage peak value Vpeak=Vac_ave*1.

57.

9. A PFC control system characterized by: The application comprises: The APFC control system according to any one of claims 6-8, configured to calculate a bus voltage setting value Vref_out; A second PI controller is configured to perform PI operation on a difference between the bus voltage setting value Vref_out and an actual bus voltage value Vdc to obtain a current setting value; A third PI controller is configured to perform PI operation on a difference between the current setting value and an actual input current value to obtain a duty cycle; A driving circuit is configured to generate a square wave signal according to the duty cycle and output the square wave signal to a power tube of the PFC circuit.

10. The PFC control system of claim 9, wherein: The PFC control system further comprises: A second multiplication module is configured to multiply the current setting value output by the second PI controller and a current phase of the input voltage to obtain a phase-adjusted current setting value; The third PI controller is configured to perform PI operation on a difference between the phase-adjusted current setting value and the actual input current value to obtain the duty cycle.

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