Active power factor correction device

Abstract

The invention relates to an active power factor correction device, in the active power factor correction device, an average current controller and a feed-forward compensation controller are respectively used for obtaining a first duty ratio and a second duty ratio, a duty ratio processor is used for superposing the first duty ratio and the second duty ratio to obtain a total duty ratio, the pulse width modulation controller is used for generating a pulse width modulation signal for controlling the switching device according to the total duty ratio, the second duty ratio is related to the sum of inductive currents sampled for multiple times in a power frequency period, and the sum of the inductive currents changes along with the load power of the main circuit. Therefore, the second duty ratio can reflect the dynamic change of the load power, the total duty ratio is obtained by superposing the first duty ratio and the second duty ratio, the feedback can be enhanced when the load power changes, and compared with the control by only using the average current method, the control capability on the output voltage and the input current is improved, and the control efficiency is improved. And a better power correction effect can be realized.

Description

Technical Field

[0001] The invention relates to the field of circuit technology, and in particular to an active power factor correction device. Background Art

[0002] Power Factor Correction (PFC) is increasingly important for driving industrial motors such as PMSM (permanent magnet synchronous motor). If power factor correction is not performed, the current generated by the control circuit will contain significant harmonic components, which will easily cause current distortion and pollute the power grid. Moreover, due to the high inductive nature of the motor load, the distorted current will add a large amount of reactive power loss to the input system, thereby reducing the efficiency of the entire system. Through power factor correction, the output voltage can be better adjusted and the harmonic content in the current can be reduced. Data shows that compared with no power factor correction, when power factor correction is added without changing the load, the peak value of the current generated by the control circuit is reduced, the distortion of the current is smaller, the pollution to the power grid is reduced, the output voltage can be better adjusted and the harmonic content in the current can be reduced.

[0003] Power factor correction is generally divided into active power factor correction (APFC) and passive power factor correction (PPFC) based on the implementation method. With the development of power electronics technology, active power factor correction has gradually become the mainstream. Active power factor correction mainly controls the switching of power devices to achieve sinusoidal current changes. It has the advantages of small size, light weight, and high power factor.

[0004] At present, active power factor correction technology usually only uses the average current method to correct the distortion of the current waveform to improve the power factor of the switching power supply and stabilize the output voltage. The average current method uses dual-loop control, in which the voltage loop as the outer control loop is used to adjust the output voltage to keep the output voltage stable, and the current loop as the inner control loop is used to control the input current waveform to follow the input voltage waveform. Usually, a PID (proportional-integral-differential) controller is used to form a compensator to perform feedback compensation on the current loop and the voltage loop.

[0005] Theoretically, by adjusting the parameters of the PID controller, the input current can track the input voltage. However, in actual control, since the input voltage changes in real time and the load power may also change dynamically, it is difficult to achieve the ideal effect using only one set of PID parameters, especially when the load is light or near the zero point of the input voltage, the reference current of the current loop is very small, the control of the entire loop is difficult, and the control effect is poor. Although some researchers have proposed the use of segmented PID parameters, on the one hand, there is a lack of theoretical guidance, the number of segments is difficult to determine, and on the other hand, parameter debugging is very complicated. Summary of the invention

[0006] In order to improve the control effect of an active power factor correction circuit on input current and output voltage, the present invention provides an active power factor correction device.

[0007] The active power factor correction device provided by the present invention comprises a main circuit and a control module, wherein the main circuit comprises a rectifier circuit and a converter circuit connected to the rectifier circuit; the control module comprises:

[0008] AD acquisition module, used for sampling the input voltage, output voltage and inductor current of the main circuit;

[0009] An average current controller, used for generating a first duty cycle according to changes in the input voltage, the output voltage and the inductor current sampled by the AD acquisition module;

[0010] A feedforward compensation controller, configured to calculate a second duty cycle according to the input voltage sampled by the AD acquisition module, the output voltage or the output voltage reference value, and the sum of the inductor current sampled multiple times within one power frequency cycle of the input voltage;

[0011] a duty cycle processor, configured to superimpose the first duty cycle and the second duty cycle to obtain a total duty cycle; and

[0012] A pulse width modulation controller is used to generate a pulse width modulation signal for controlling the switching device in the converter circuit to turn on and off according to the total duty cycle.

[0013] Optionally, the feedforward compensation controller obtains the second duty cycle according to equation (1) or equation (2); wherein,

[0014] Equation (1) is D f = k*I all *(1-V ac / V bus_m ), where D f represents the second duty cycle, k represents the correction coefficient, I all represents the sum of the inductor current sampled multiple times within one power frequency cycle of the input voltage, V ac Represents the absolute value of the input voltage, V bus_m represents a sampled value of the output voltage;

[0015] Equation (2) is D f = k*I all *(1-V ac / V bus_ref ), where D f represents the second duty cycle, k represents the correction coefficient, Iall represents the sum of the inductor current sampled multiple times within one power frequency cycle of the input voltage, V ac Represents the absolute value of the input voltage, V bus_ref Represents the output voltage reference value.

[0016] Optionally, the AD acquisition module samples the inductor current n times within half of the power frequency cycle, n=f1 / f2, f1 is the control frequency of power factor correction, f2 is twice the power frequency, and the feedforward compensation controller sums the values ​​of the n inductor currents sampled within half of the power frequency cycle to obtain the sum of the inductor currents and calculate the second duty cycle; or

[0017] The AD acquisition module samples the inductor current n times within one power frequency cycle, where n=f1 / f2, f1 is the control frequency of the power factor correction, and f2 is the power frequency. The feedforward compensation controller sums the values ​​of the n inductor currents sampled within one power frequency cycle to obtain the sum of the inductor currents and calculate the second duty cycle.

[0018] Optionally, within the one power frequency cycle, the AD acquisition module samples the inductor current according to a fixed cycle.

[0019] Optionally, the average current controller comprises:

[0020] a voltage control loop, for comparing the sampled output voltage with the output voltage reference value to generate an output voltage error amplification signal, and performing a PID operation on the output voltage error amplification signal to generate a reference current; and

[0021] A current control loop is used to multiply the reference current and the absolute value of the input voltage to generate a reference current, compare the inductor current and the reference current to generate a current error signal, and perform a PID operation on the current error signal to generate the first duty cycle.

[0022] Optionally, the rectifier circuit includes an AC current source and a rectifier bridge circuit consisting of four diodes.

[0023] Optionally, in addition to the switching device, the converter circuit also includes an inductor, one end of the inductor is connected to the positive output end of the rectifier circuit, and the other end of the inductor is connected to the first end of the switching device; wherein the inductor current is the current collected by the AD acquisition module at the second end of the switching device.

[0024] Optionally, the converter circuit further includes:

[0025] a first resistor, wherein the second end of the switch device is connected to the negative output end of the rectifier circuit through the first resistor;

[0026] A freewheeling diode, an anode end of which is connected to the other end of the inductor;

[0027] an output filter capacitor, a positive electrode of which is connected to the cathode end of the freewheeling diode, and a negative electrode of which is connected to the negative output end of the rectifier circuit; and

[0028] The second resistor and the third resistor are connected in series between the cathode end of the freewheeling diode and the negative output end of the rectifier circuit.

[0029] Optionally, the switch device is a PMOSFET, the first end of the switch device is a drain end of the PMOSFET, and the second end of the switch device is a source end of the PMOSFET.

[0030] Optionally, in the control module, at least one of the AD acquisition module, the average current controller, the feedforward compensation controller, the duty cycle processor and the pulse width modulation controller is implemented using a microprocessor.

[0031] In the active power factor correction device provided by the present invention, the control module includes an AD acquisition module, an average current controller, a feedforward compensation controller, a duty cycle processor and a pulse width modulation controller, wherein the first duty cycle and the second duty cycle can be obtained by using the average current controller and the feedforward compensation controller respectively, and the first duty cycle and the second duty cycle are added together by the duty cycle processor to obtain a total duty cycle, and the pulse width modulation controller can generate a pulse width modulation signal for controlling the switching device in the converter circuit to be turned on and off according to the total duty cycle. The feedforward compensation controller calculates the second duty cycle based on the input voltage sampled by the AD acquisition module, the output voltage or the output voltage reference value, and the sum of the inductor current sampled multiple times within one power frequency cycle of the input voltage. The sum of the inductor current changes with the load power of the main circuit, so that the second duty cycle can reflect the dynamic change of the load power. The total duty cycle is obtained by superimposing the first duty cycle and the second duty cycle, which can enhance feedback when the load power changes. Compared with control using only the average current method, the control ability of the output voltage and input current is improved, and a better power correction effect can be achieved. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 4 is a circuit diagram of an active power factor correction device according to an embodiment of the present invention.

[0033] Figure 2The diagram is a schematic diagram of the input voltage after rectification and the inductor current sampled multiple times in one power frequency cycle of the active power factor correction device according to an embodiment of the present invention.

[0034] Figure 3 3 is a curve showing a change in the input voltage after rectification and the second duty cycle of the active power factor correction device according to an embodiment of the present invention. DETAILED DESCRIPTION

[0035] The active power factor correction device of the present invention is further described in detail below in conjunction with the accompanying drawings and specific embodiments. The advantages and features of the present invention will become clearer according to the following description. It should be noted that the accompanying drawings are all in a very simplified form and are not in precise proportions, and are only used to conveniently and clearly assist in explaining the purpose of the embodiments of the present invention.

[0036] As described in the background technology, only the average current method is used for active power factor correction, and the effect is not ideal, especially when the load is light or near the input voltage zero point, the reference current of the current loop is very small, the control difficulty of the entire loop is large, and the control effect is poor. To this end, an embodiment of the present invention introduces an active power factor correction device, which adds feedforward compensation on the basis of the average current method, which can overcome the disadvantages of the loop system of the average current method when the load is light and the input voltage crosses the zero point, meet the needs of dynamic load changes, and improve the control ability of the output voltage and input current.

[0037] Figure 1 Schematic diagram of the circuit of the active power factor correction device according to the embodiment of the present invention. Figure 1 In the embodiment of the present invention, the active power factor correction device includes a main circuit 10 and a control module 20, wherein the main circuit 10 includes a rectifier circuit 11 and a converter circuit 12 connected to the rectifier circuit 11, and the control module 20 samples the input voltage, output voltage and inductor current I of the main circuit 10. L , and generates a pulse width modulation signal for controlling the switching device Q in the converter circuit 12 to be turned on and off.

[0038] In the main circuit 10, the rectifier circuit 11 is used to convert the AC input voltage V ac Convert to DC voltage. Figure 1As shown, the rectifier circuit includes an AC current source and a rectifier bridge circuit composed of four diodes. Specifically, the four diodes are a first diode D1, a second diode D2, a third diode D3 and a fourth diode D4, wherein one end of the AC current source is connected to the anode end of the first diode D1 and the other end is connected to the anode end of the second diode D2, the cathode end of the third diode D3 is connected to the anode end of the first diode D1, the cathode end of the fourth diode D4 is connected to the anode end of the second diode D2, the cathode ends of the first diode D1 and the second diode D2 are connected as the positive output end of the rectifier circuit 11, and the anode ends of the third diode D3 and the fourth diode D4 are connected as the negative output end of the rectifier circuit 11, and the negative output end is, for example, grounded.

[0039] The converter circuit 12 is connected to the rectifier circuit 11. The converter circuit 12 stores and releases energy in the inductor L by turning on and off the switch device Q, and generates an output voltage. The converter circuit 12 can adopt a boost topology, a buck topology, a buck-boost topology, a forward topology, or a flyback topology. As an example, in this embodiment, the converter circuit 12 adopts a boost topology.

[0040] like Figure 1 As shown, the converter circuit 12 includes an inductor L, a switch device Q, a freewheeling diode D5, an output filter capacitor C, a first resistor R1, a second resistor R2 and a third resistor R3; wherein one end of the inductor L is connected to the positive output end of the rectifier circuit 11, the other end of the inductor L is connected to the first end of the switch device Q, and the second end of the switch device Q is connected to the negative output end of the rectifier circuit 11 through the first resistor R1; the anode end of the freewheeling diode D5 is connected to the other end of the inductor L; the positive electrode of the output filter capacitor C is connected to the cathode end of the freewheeling diode D5, and the negative electrode of the output filter capacitor C is connected to the negative output end of the rectifier circuit 11; the second resistor R2 and the third resistor R3 are connected in series between the cathode end of the freewheeling diode D5 and the negative output end of the rectifier circuit 11. The load 30 of the active power factor correction device is connected between the positive electrode and the negative electrode of the output filter capacitor C. The switch device Q is, for example, a PMOSFET, the first end of the switch device Q is, for example, a drain end of the PMOSFET, and the second end of the switch device Q is, for example, a source end of the PMOSFET.

[0041] The control module 20 includes an AD acquisition module, an average current controller 22, a feedforward compensation controller 23, a duty cycle processor 24, and a pulse width modulation controller 25. The control module 20 can be implemented in the form of a hardware circuit, however, at least a portion of the control circuit 20 can also be implemented in a software manner, for example, in the form of a software program in conjunction with a device or equipment. As an example, at least one of the AD acquisition module, the average current controller 22, the feedforward compensation controller 23, the duty cycle processor 24, and the pulse width modulation controller 25 is implemented using a microprocessor (MCU).

[0042] Specifically, in the control module 20, the AD acquisition module is used to sample the input voltage (AC input voltage V ac Or the rectified input voltage, V ac The AD acquisition module can perform A / D conversion on the sampled input voltage, output voltage and inductor current of the main circuit 10.

[0043] Specifically, Figure 1 As shown, the AD acquisition module may include a first acquisition unit 21a, a second acquisition unit 21b and a third acquisition unit 21c. The first acquisition unit 21a is used to sample the input voltage of the main circuit 10. The input voltage of the main circuit 10 can be obtained by sampling the AC input voltage V ac Or the rectified input voltage is obtained. In this embodiment, the first acquisition unit 21a acquires the AC input voltage V ac As the input voltage (V ac ). The second acquisition unit 21b is used to sample the output voltage (i.e., bus voltage) of the main circuit 10. The change of the output voltage can be reflected from the voltage change of the node between the second resistor R2 and the third resistor R3. Thus, the second acquisition unit 21b of this embodiment obtains the sampled value of the output voltage from the node between the second resistor R2 and the third resistor R3, which is recorded as the sampled output voltage Vbus_m. The third acquisition unit 21c is used to sample the inductor current I of the main circuit 10. L , the inductor current I L For example, it is the current collected by the AD acquisition module at the second end of the switching device Q.

[0044] The average current controller 22 is used to obtain the input voltage (V ac ), the output voltage and the inductor current I L The first duty cycle D is generated by the change of pi The specific structure of the average current controller 22 can be set by using the average current method active power factor correction technology currently available in the art.

[0045] As an example, the average current controller includes a voltage control loop and a current control loop. The voltage control loop is used to compare the sampled output voltage (ie, the sampled output voltage Vbus_m) with an output voltage reference value V bus_ref (Output voltage reference value V bus_ref The output voltage error amplification signal is generated by the output voltage amplification signal, and the output voltage error amplification signal is input into the voltage loop PID (shown as PID1) to perform PID operation on the output voltage error amplification signal to generate a reference current I ref* The reference current I ref* is associated with the output voltage error amplified signal.

[0046] The current control loop is used to make the reference current I ref* and the input voltage (V ac ) to generate the reference current I ref , and compares the inductor current I L and the reference current I ref To generate a current error signal, the current error signal can be further input into the current loop PID (shown as PID2) for calculation. The current control loop is also used to perform PID operation on the current error signal to generate a first duty cycle D pi The first duty cycle D pi is associated with the current error signal.

[0047] By making the reference current I ref* and the input voltage (V ac ) to generate the reference current I ref , the reference current I ref The input voltage (V ac ) are in phase.

[0048] In the control module 20, the feedforward compensation controller 23 is used to generate a voltage according to the input voltage (V ac ), the output voltage sampled by the AD acquisition module (i.e., the sampled output voltage V bus_m ) or output voltage reference value V bus_ref , and at the input voltage (V ac ) is the inductor current I sampled multiple times within one power frequency cycle L The second duty cycle is calculated by summing the values ​​of

[0049] As an example, the feedforward compensation controller 23 may use equation (1) or equation (2) as described below to obtain the second duty cycle.

[0050] Specifically, in one embodiment, the feedforward compensation controller 23 obtains the second duty cycle according to the following equation (1):

[0051] D f = k*I all *(1-V ac / V bus_m ) (1)

[0052] In equation (1), D f represents the second duty cycle, k represents the correction coefficient, I all Indicates the input voltage (V ac ) is the inductor current I sampled multiple times within one power frequency cycle L The sum of V ac Indicates input voltage (V ac ), V bus_m Indicates the sampled output voltage V bus_m (ie the sampled value of the output voltage).

[0053] In another embodiment, the feedforward compensation controller 23 obtains the second duty cycle according to the following equation (2):

[0054] D f = k*I all *(1-V ac / V bus_ref ) (2)

[0055] In equation (2), D f represents the second duty cycle, k represents the correction coefficient, I all Indicates the input voltage (V ac ) is the inductor current I sampled multiple times within one power frequency cycle L The sum of V ac Indicates input voltage (V ac ), V bus_ref Indicates the output voltage reference value.

[0056] In the above equations (1) and (2), when the input voltage (V ac ) is the inductor current I sampled multiple times within one power frequency cycle L The sum of I all Satisfies the following equation (3):

[0057] I all =I L1 +I L2 +I L3 +…I Ln (3)

[0058] In equation (3), IL1 ,I L2 ,I L3 and I Ln The inductor current I obtained by the first sampling, the second sampling, the third sampling and the nth sampling in one power frequency cycle are L Since the rectifier current is set, at the input voltage (V ac ) in one power frequency cycle, the inductor current I L The change of I has gone through two cycles. Therefore, in one embodiment, the AD acquisition module acquires the inductor current I within half of the power frequency cycle. L The sampling is performed n times, where n is the quotient of f1 and f2 (i.e., n=f1 / f2), f1 is the control frequency of the power factor correction, and f2 is twice the power frequency. The feedforward compensation controller 23 samples the n inductor currents I in the half power frequency cycle. L The inductor current I is obtained by summing the values ​​of L The sum of I all , the second duty cycle D can be further calculated using the above equation (1) or equation (2): f The present invention is not limited to this. In another embodiment, the AD acquisition module collects the inductor current I L The sample is taken n times, n=f1 / f2, f1 is the control frequency of the power factor correction, f2 is the power frequency, and the feedforward compensation controller 23 sums the values ​​of the n inductor currents sampled in one power frequency cycle to obtain the inductor current I L The sum of I all , further use the above equation (1) or equation (2) to calculate the second duty cycle D f It is worth noting that the method described here to obtain the inductor current I L The sum of I all The previous embodiment only needs to adjust the inductor current I in half of the power frequency cycle. L Sampling, the required sampling time is shorter, and the latter embodiment samples the inductor current I L Sampling, more sampling times, more accurate calculation, making I all The calculation is more accurate. When calculating the second duty cycle D f When the inductor current I is obtained by using different methods L The sum of I all The two embodiments adopt different correction coefficients k.

[0059] Optionally, the input voltage (V ac ), the AD acquisition module samples the inductor current according to a fixed period.

[0060] According to equation (1) or equation (2), the second duty cycle D f The inductor current I sampled within one power frequency cycle L The sum of I all increases, and the inductor current I L The sum of I all As the load power of the main circuit 10 changes, the second duty cycle D f It can reflect the dynamic change of load power, and according to equations (1) and (2), when the input voltage (V ac ) is smaller, the second duty cycle D f The larger the value, the larger the feedforward value that can be achieved. Compared with controlling only by the average current method when the load is light and the input voltage crosses zero, the control capability of the output voltage and input current is improved, and a better power correction effect can be achieved.

[0061] Figure 2 is the input voltage (V ac ) and the inductor current (I L ) amplitude diagram. Figure 2 , at the input voltage (V ac ) within a power frequency cycle, the inductor current I sampled multiple times L The value of is related to the load power. Since the output voltage of the main circuit 10 is basically unchanged, the inductor current I L The area formed by the envelope of can represent the load power to a certain extent. The greater the load power, the greater the inductor current I L The sum of I all The larger the second duty cycle D f By sampling the inductor current I multiple times in one power frequency cycle L And add them together, the resulting inductor current I L The sum of I all It can reflect the change of load power size. Compared with obtaining the power size change by sampling the output voltage and output current and calculating the power, it can avoid the interference and fluctuation that may exist in the calculation process.

[0062] In the embodiment of the present invention, the feedforward compensation controller 23 is based on the input voltage (V ac ), output voltage (i.e., sampled output voltage V bus_m ) or output voltage reference value V bus_ref , and the input voltage (V ac ) is the inductor current I sampled multiple times within one power frequency cycle L The sum of I allCalculate the second duty cycle D f These signals can be shared with the average current controller 22, and there is no need to add new sampling signals and additional circuit assistance, which will not significantly increase the complexity of the circuit.

[0063] In the control module 20, the duty cycle processor 24 is connected to the output ends of the average current controller 22 and the feedforward compensation controller 23 to obtain the first duty cycle D pi and the second duty cycle D f The duty cycle processor 24 is used to superimpose the first duty cycle D pi and the second duty cycle D f , to obtain the total duty cycle. In the total duty cycle, the second duty cycle D f As the first duty cycle D pi The compensation amount is related to the input voltage (V ac ) and the input voltage (V ac ) is the inductor current I sampled multiple times within one power frequency cycle L The sum of I all According to equation (1) or equation (2), when the input voltage (V ac ) is smaller, the second duty cycle D f The larger it is, the larger the feedforward value can be achieved. Figure 3 shows the input voltage (V ac ) with 10 times the second duty cycle D f The amplitude change curve of Figure 3 As shown, when the input voltage (V ac ) is the largest, the second duty cycle D f is the minimum value, when the input voltage (V ac ) crosses zero, the second duty cycle D f In addition, according to equations (1) and (2), the second duty cycle D can be adjusted by adjusting the correction coefficient k. f The specific value of the second duty cycle D can be adjusted f For the first duty cycle D pi The amount of compensation.

[0064] In the control module 20, the pulse width modulation controller 25 is used to generate a pulse width modulation signal for controlling the switching device Q to turn on and off according to the total duty cycle. The pulse width modulation signal, for example, has a pulse waveform corresponding to the total duty cycle. By controlling the control terminal of the switching device Q with the pulse width modulation signal, the on time and off time of the switching device Q can be controlled. In general, when the inductor current I LWhen the pulse width modulation signal increases, the total duty cycle, i.e., the duty cycle of the pulse width modulation signal, decreases, so that the inductor current I L decreases, on the contrary, when the inductor current I L When the pulse width modulation signal is decreased, the total duty cycle, i.e., the duty cycle of the pulse width modulation signal, increases, so that the inductor current I L increases, causing the inductor current I L Approaching the average current, the input current tracks the input voltage (V ac ) so as to improve the power factor. At the same time, when the output voltage of the main circuit 10 rises, the sampled output voltage V bus_m The output voltage error amplified signal generated by the voltage control loop decreases, and then the reference current I used by the current control loop decreases. ref decreases, making the inductor current I L The output voltage of the converter circuit 12 decreases, thereby achieving the purpose of stabilizing the output voltage.

[0065] In the active power factor correction device described in the above embodiment, the control module 20 includes an AD acquisition module, an average current controller 22, a feedforward compensation controller 23, a duty cycle processor 24 and a pulse width modulation controller 25, wherein the first duty cycle D can be obtained by using the average current controller 22 and the feedforward compensation controller 23 respectively. pi and the second duty cycle D f , using the duty cycle processor 24 to superimpose the first duty cycle D pi and the second duty cycle D f The total duty cycle can be obtained, and the pulse width modulation controller 25 can generate a pulse width modulation signal for controlling the switching device according to the total duty cycle. f The inductor current I sampled multiple times in one power frequency cycle L The sum of I all Regarding the inductor current I L The sum of I all As the load power of the main circuit 10 changes, the second duty cycle D f It can reflect the dynamic change of load power by superimposing the first duty cycle D pi and the second duty cycle D f Obtaining the total duty cycle can enhance feedback when the load power changes. Compared with control using only the average current method, the control capability of the output voltage and input current is improved, and a better power correction effect can be achieved.

[0066] The above description is only a description of the preferred embodiment of the present invention, and is not any limitation on the scope of rights of the present invention. Any technical personnel in this field can make possible changes and modifications to the technical solution of the present invention by using the methods and technical contents disclosed above without departing from the spirit and scope of the present invention. Therefore, any simple modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention shall fall within the protection scope of the technical solution of the present invention.

Claims

1. An active power factor correction device, characterized in that: The invention comprises a main circuit and a control module, wherein the main circuit comprises a rectifier circuit and a converter circuit connected to the rectifier circuit; and the control module comprises: AD acquisition module, used for sampling the input voltage, output voltage and inductor current of the main circuit; An average current controller, used for generating a first duty cycle according to changes in the input voltage, the output voltage and the inductor current sampled by the AD acquisition module; A feedforward compensation controller, configured to calculate a second duty cycle according to the input voltage sampled by the AD acquisition module, the output voltage or the output voltage reference value, and the sum of the inductor current sampled multiple times within one power frequency cycle of the input voltage; a duty cycle processor, configured to superimpose the first duty cycle and the second duty cycle to obtain a total duty cycle; and A pulse width modulation controller is used to generate a pulse width modulation signal for controlling the switching device in the converter circuit to turn on and off according to the total duty cycle.

2. The active power factor correction device according to claim 1, characterized in that: The feedforward compensation controller obtains the second duty cycle according to equation (1) or equation (2); wherein, Equation (1) is D f = k*I all *(1-V ac / V bus_m ), where D f represents the second duty cycle, k represents the correction coefficient, I all represents the sum of the inductor current sampled multiple times within one power frequency cycle of the input voltage, V ac Represents the absolute value of the input voltage, V bus_m represents a sampled value of the output voltage; Equation (2) is D f = k*I all *(1-V ac / V bus_ref ), where D f represents the second duty cycle, k represents the correction coefficient, I all represents the sum of the inductor current sampled multiple times within one power frequency cycle of the input voltage, V ac Represents the absolute value of the input voltage, V bus_ref Represents the output voltage reference value.

3. The active power factor correction device according to claim 1, characterized in that: The AD acquisition module samples the inductor current n times within half of the power frequency cycle, where n=f1 / f2, f1 is the control frequency of the power factor correction, and f2 is twice the power frequency. The feedforward compensation controller sums the values ​​of the n inductor currents sampled within half of the power frequency cycle to obtain the sum of the inductor currents and calculate the second duty cycle; or, The AD acquisition module samples the inductor current n times within one power frequency cycle, where n=f1 / f2, f1 is the control frequency of the power factor correction, and f2 is the power frequency. The feedforward compensation controller sums the values ​​of the n inductor currents sampled within one power frequency cycle to obtain the sum of the inductor currents and calculate the second duty cycle.

4. The active power factor correction device according to claim 1, characterized in that: In the one power frequency cycle, the AD acquisition module samples the inductor current according to a fixed cycle.

5. The active power factor correction device according to claim 1, characterized in that: The average current controller comprises: a voltage control loop, for comparing the sampled output voltage with the output voltage reference value to generate an output voltage error amplification signal, and performing a PID operation on the output voltage error amplification signal to generate a reference current; and A current control loop is used to multiply the reference current and the absolute value of the input voltage to generate a reference current, compare the inductor current and the reference current to generate a current error signal, and perform a PID operation on the current error signal to generate the first duty cycle.

6. The active power factor correction device according to claim 1, characterized in that: The rectifier circuit includes an AC current source and a rectifier bridge circuit composed of four diodes.

7. The active power factor correction device according to claim 1, characterized in that: In addition to the switching device, the converter circuit also includes an inductor, one end of the inductor is connected to the positive output end of the rectifier circuit, and the other end of the inductor is connected to the first end of the switching device; wherein the inductor current is the current collected by the AD acquisition module at the second end of the switching device.

8. The active power factor correction device according to claim 7, characterized in that: The converter circuit further comprises: a first resistor, wherein the second end of the switch device is connected to the negative output end of the rectifier circuit through the first resistor; A freewheeling diode, an anode end of which is connected to the other end of the inductor; an output filter capacitor, a positive electrode of which is connected to the cathode end of the freewheeling diode, and a negative electrode of which is connected to the negative output end of the rectifier circuit; and The second resistor and the third resistor are connected in series between the cathode end of the freewheeling diode and the negative output end of the rectifier circuit.

9. The active power factor correction device according to claim 7, characterized in that: The switch device is a PMOSFET, the first end of the switch device is a drain end of the PMOSFET, and the second end of the switch device is a source end of the PMOSFET.

10. The active power factor correction device according to any one of claims 1 to 9, characterized in that: In the control module, at least one of the AD acquisition module, the average current controller, the feedforward compensation controller, the duty cycle processor and the pulse width modulation controller is implemented by a microprocessor.

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