Control system and control method of BUCK type PFC (Power Factor Correction) circuit

Abstract

The invention provides a control system and a control method of a BUCK type PFC (Power Factor Correction) circuit. In the control system, alternating current voltage is input to one side of a rectifying unit, and the other side of the rectifying unit is coupled with one side of a first filtering unit; the other side of the first filtering unit is coupled with one side of the BUCK type PFC circuit; the other side of the BUCK type PFC circuit is coupled with one side of the composite filtering unit; the other side of the composite filtering unit is used for being coupled with a load end; the control unit is used for collecting the output voltage and the output current of the rectification unit and the output voltage of the composite filtering unit; and the control unit is also used for outputting a PWM control signal to the BUCK type PFC circuit through a feedforward and nonlinear control algorithm according to the output voltage and the output current of the rectification unit and the output voltage of the composite filtering unit, and the PWM control signal is used for controlling the on-off of a switching tube in the BUCK type PFC circuit. By means of the control system, the problem that in the control mode of the BUCK type PFC circuit, it is difficult to enable the circuit to reach a high power factor while the low-current THD of the circuit is guaranteed is solved.

Description

Technical Field

[0001] The present invention relates to the technical field of circuit control, and in particular to a control system and a control method of a BUCK type PFC circuit. Background Art

[0002] The typical characteristics of the BUCK PFC circuit are that it has a step-down characteristic and the voltage stress on the device is low, which is particularly suitable for high-voltage input and low-voltage output power supply. With the increasing demand for low-voltage power supply loads, Buck PFC technology is receiving more and more attention. In a single-phase circuit, when the instantaneous value of the input voltage is lower than the output voltage, the BUCK PFC circuit has an inherent input current dead zone problem, which greatly increases the current total harmonic distortion (THD). In order to solve the current dead zone problem, many methods have emerged, such as constant on-time soft switching method, harmonic current compensation method, LC filter-based BUCK PFC, and Buck-Boost mode.

[0003] However, in the related art, for the control method of the single-phase input BUCK type PFC circuit, it is difficult to ensure a low current THD of the circuit while making the circuit achieve a higher power factor. Summary of the invention

[0004] The present invention provides a control system and a control method for a BUCK type PFC circuit, which are used to solve the problem in the related art that it is difficult to achieve a higher power factor while ensuring a low current THD of the circuit for the control method of the single-phase input BUCK type PFC circuit.

[0005] The present invention provides a control system of a BUCK type PFC circuit, comprising: a rectifier unit, a first filter unit, a BUCK type PFC circuit, a composite filter unit and a control unit; One side of the rectifying unit is input with an AC voltage, and the other side is coupled with one side of the first filtering unit; The other side of the first filter unit is coupled to one side of the BUCK type PFC circuit; The other side of the BUCK type PFC circuit is coupled to one side of the composite filter unit; The other side of the composite filter unit is used to couple with the load end; The control unit is used to collect the output voltage and output current of the rectifier unit and the output voltage of the composite filter unit; and is also used to output a PWM control signal to the BUCK type PFC circuit according to the output voltage and output current of the rectifier unit and the output voltage of the composite filter unit, wherein the PWM control signal is used to control the on and off of the switch tube in the BUCK type PFC circuit.

[0006] According to the control system of the BUCK type PFC circuit provided by the present invention, the first filtering unit is a CLC filter.

[0007] The control system of the BUCK type PFC circuit provided according to the present invention further includes a capacitor, one side of the capacitor is coupled to one side of the BUCK type PFC circuit, and the other side is grounded; the capacitor is connected in parallel with the BUCK type PFC circuit to form a second filtering unit.

[0008] According to the control system of the BUCK type PFC circuit provided by the present invention, the rectifying unit is composed of a plurality of rectifying diodes.

[0009] According to any one of the control systems of the BUCK type PFC circuit provided by the present invention, the CLC filter is used to filter the higher harmonics in the BUCK type PFC circuit.

[0010] The present invention further provides a control method for a BUCK type PFC circuit, which is applied to any control system of the BUCK type PFC circuit, and comprises: Collecting the output voltage and output current of the rectifying unit and the output voltage of the composite filtering unit; According to the output voltage and output current of the rectifier unit and the output voltage of the composite filter unit, a PWM control signal is output to the BUCK type PFC circuit, and the PWM control signal is used to control the shutdown of the BUCK type PFC circuit.

[0011] According to the control method of the BUCK type PFC circuit provided by the present invention, the outputting of the PWM control signal to the BUCK type PFC circuit according to the output voltage and output current of the rectifier unit and the output voltage of the composite filter unit comprises: Performing proportional transformation on the reference voltage and the output voltage of the composite filter unit respectively, and comparing the proportional transformation results to obtain a first compensation deviation; performing an outer loop PI operation on the first compensation deviation to obtain a first compensation output; After the output voltage of the rectifier unit is proportionally transformed once, the output voltage is input into a multiplier with the first compensation output to obtain a first current reference item; and after the output voltage of the rectifier unit is proportionally transformed once, the output voltage is proportionally transformed again to obtain a current reference feedforward item; Obtaining a reference current according to the first current reference term and the current reference feedforward term; The output current of the rectifying unit is proportionally converted and compared with the reference current to obtain a second compensation deviation; An inner loop PI operation is performed on the second compensation deviation to obtain a compensation signal; and the compensation signal is modulated to output a PWM control signal to the BUCK type PFC circuit.

[0012] The present invention also provides an electronic device, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor implements any of the above-described control methods for the BUCK-type PFC circuit when executing the computer program.

[0013] The present invention also provides a non-transitory computer-readable storage medium on which a computer program is stored. When the computer program is executed by a processor, the control method of the BUCK type PFC circuit as described in any one of the above is implemented.

[0014] The present invention also provides a computer program product, comprising a computer program, wherein when the computer program is executed by a processor, the control method of the BUCK type PFC circuit as described above is implemented.

[0015] The control system and control method of the BUCK type PFC circuit provided by the present invention combine multiple filtering modes; collect the output voltage and output current of the rectifier unit and the output voltage of the composite filtering unit to perform PWM control on the BUCK type PFC circuit, perform a proportional transformation on the output voltage of the rectifier unit, and then perform a proportional transformation again to obtain a current reference feedforward item; and in the subsequent PI calculation process, the current reference feedforward item is applied to the reference current, so that the circuit can achieve a high power factor while also having the purpose of low current THD. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the technical solutions in the present invention or the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0017] Figure 1This is one of the structural schematic diagrams of the control system of the BUCK type PFC circuit provided by the present invention.

[0018] Figure 2 This is the second structural schematic diagram of the control system of the BUCK type PFC circuit provided by the present invention.

[0019] Figure 3 This is one of the flow charts of the control method of the BUCK type PFC circuit provided by the present invention.

[0020] Figure 4 This is the second flow chart of the control method of the BUCK type PFC circuit provided by the present invention.

[0021] Figure 5 It is a schematic diagram of the principle of a process of obtaining a PWM control signal provided by the present invention.

[0022] Figure 6 This is one of the principle schematic diagrams of a simulation result provided by the present invention.

[0023] Figure 7 This is the second principle schematic diagram of a simulation result provided by the present invention.

[0024] Figure 8 It is a structural schematic diagram of the electronic device provided by the present invention. DETAILED DESCRIPTION

[0025] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention will be clearly and completely described below in conjunction with the drawings of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0026] The terms "first", "second", etc. in the specification and claims of the present application and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the descriptions used in this way can be interchanged where appropriate, so that the embodiments can be implemented in a sequence other than that illustrated or described in the present application. In addition, the terms "including" and "having" and any of their variations are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device that includes a series of steps or modules is not necessarily limited to those steps or modules that are clearly listed, but may include other steps or modules that are not clearly listed or inherent to these processes, methods, products or devices. The naming or numbering of the steps that appear in the present application does not mean that the steps in the method flow must be executed in the time / logical sequence indicated by the naming or numbering. The process steps that have been named or numbered can change the execution order according to the technical purpose to be achieved, as long as the same or similar technical effects can be achieved. The division of modules in this application is a logical division. There may be other division methods when it is implemented in actual applications. For example, multiple modules can be combined or integrated into another system, or some features can be ignored or not executed. In addition, the mutual coupling or direct coupling or communication connection shown or discussed can be through some interfaces, and the indirect coupling or communication connection between units can be electrical or other similar forms, which are not limited in this application. In addition, the modules or submodules described as separate components may or may not be physically separated, may or may not be physical units, or may be distributed in multiple circuit units, and some or all of the units may be selected according to actual needs to achieve the purpose of the present application.

[0027] The typical characteristics of the BUCK PFC circuit are that it has a step-down characteristic and the voltage stress on the device is low. It is particularly suitable for high-voltage input and low-voltage output power supply. With the increasing demand for low-voltage power supply loads, Buck PFC technology is receiving more and more attention. In a single-phase circuit, when the instantaneous value of the input voltage is lower than the output voltage, the BUCK PFC circuit has an inherent input current dead zone problem, which greatly increases the harmonic current content. To solve the above problem, many methods have emerged, such as (1) constant on-time soft switching method: based on constant on-time control, the inductor current is made to work in critical mode to achieve soft switching, but the input current harmonics of this method are still difficult to meet the standard requirements. (2) Harmonic current compensation method: by introducing a harmonic current compensation signal, the harmonic current is reduced, but the control is more complicated and the design is more difficult. The above two schemes still have the inherent dead zone problem of the input current of the BUCK PFC circuit, and as the input voltage decreases, the harmonic content increases. (3) Buck-type PFC circuit based on LC filter: The buck-type PFC circuit uses an LC filter on the input side, which makes the capacitor voltage of the input filter work in discontinuous mode, eliminating the input current dead zone; but the voltage stress of the switch tube is relatively large.

[0028] In summary, in the related art, for the control method of the single-phase input BUCK type PFC circuit, it is impossible to ensure the low current THD of the circuit while making the circuit achieve a higher power factor. The present invention aims to improve the BUCK type PFC circuit and combine it with a feedforward control method to make the single-phase input BUCK type PFC circuit achieve a higher power factor while having a low current THD.

[0029] Combine the following Figure 1-Figure 8 The specific contents of the present invention are described.

[0030] Figure 1 FIG. 1 is one of the structural diagrams of the control system of the BUCK type PFC circuit provided by the present invention, such as Figure 1 As shown, the control system includes the following: a rectifying unit, a first filtering unit, a BUCK type PFC circuit, a composite filtering unit and a control unit.

[0031] like Figure 1As shown, one side of the rectifier unit inputs an AC voltage, and the other side is coupled to one side of the first filter unit; the other side of the first filter unit is coupled to one side of the BUCK type PFC circuit; the other side of the BUCK type PFC circuit is coupled to one side of the composite filter unit; the other side of the composite filter unit is used to couple to the load end; the control unit is used to collect the output voltage and output current of the rectifier unit and the output voltage of the composite filter unit; and is also used to output a PWM control signal to the BUCK type PFC circuit according to the output voltage and output current of the rectifier unit and the output voltage of the composite filter unit, and the PWM control signal is used to control the on and off of the switch tube in the BUCK type PFC circuit.

[0032] In a possible implementation manner, the first filtering unit is a CLC filter.

[0033] In a possible implementation manner, a capacitor is further included, one side of the capacitor is coupled to one side of the BUCK-type PFC circuit, and the other side of the capacitor is grounded; the capacitor is connected in parallel with the BUCK-type PFC circuit to form a second filtering unit.

[0034] In a possible implementation, the rectifying unit is formed by a plurality of rectifying diodes.

[0035] In a possible implementation, a CLC filter is used to filter high-order harmonics in a BUCK-type PFC circuit.

[0036] In the embodiment of the present invention, the specific structure of the control system of the BUCK type PFC circuit is as follows: Figure 2 shown.

[0037] In the embodiment of the present invention, the rectifying unit includes diodes D1 , D2 , D3 and D4 , which form a rectifying bridge to rectify the AC input voltage.

[0038] In an embodiment of the present invention, the first filtering unit is a CLC filter, including a capacitor C1, a capacitor C2 and an inductor L1. The CLC filter suppresses the AC harmonic signal in the system and retains the DC signal through the combination of the capacitor C1, the capacitor C2 and the inductor L1, thereby improving the stability of the output DC voltage.

[0039] In an embodiment of the present invention, the BUCK type PFC circuit includes a capacitor C4 and an inductor L2. The system further includes a capacitor C3, one side of the capacitor C3 is coupled to one side of the BUCK type PFC circuit, and the other side is grounded; the capacitor C3 is connected in parallel with the BUCK type PFC circuit to form a second filtering unit.

[0040] In the embodiment of the present invention, the AC voltage is 220V AC voltage input. is the output voltage of the rectifier module, is the output current of the rectifier module, is the output voltage of the composite filter unit, that is, the voltage at the load end.

[0041] In the embodiment of the present invention, the composite filter unit includes a capacitor C5, an inductor L3 and an inductor L4, which form a composite filter circuit to smooth the output fluctuation of the BUCK type PFC circuit.

[0042] Specifically, the control unit consists of two parts: PWM drive and PI operation control.

[0043] sampling ,Will and reference voltage Together they serve as the input of the voltage outer loop controller in the PI operation control, and are sent to the current inner loop controller after PI operation.

[0044] sampling , , and is sent to the inner loop control link together with the input of the voltage outer loop controller link, and after the PI operation of the current inner loop controller, the output control quantity of the current inner loop controller is formed.

[0045] The control quantity generated by the current inner loop controller forms the control signal of the BUCK type PFC circuit after PWM drive to control the output voltage Tracking reference voltage , and together with the first filtering unit and the composite filtering unit, the purpose of improving the power factor in the circuit and reducing the current THD is achieved.

[0046] In the embodiment of the present invention, the specific control mode of the control unit refers to the embodiment of the method side described below. The control method of the BUCK type PFC circuit in the embodiment of the present invention is applied to any control system of the BUCK type PFC circuit provided by the present invention.

[0047] Figure 3 A flowchart of a control method for a BUCK type PFC circuit provided by an embodiment of the present invention includes steps S301-S302.

[0048] Step S301 , collecting the output voltage and output current of the rectifying unit and the output voltage of the composite filtering unit.

[0049] Step S302: outputting a PWM control signal to the BUCK type PFC circuit according to the output voltage and output current of the rectifier unit and the output voltage of the composite filter unit. The PWM control signal is used to control the on and off of the switch tube in the BUCK type PFC circuit.

[0050] In a possible implementation, in step S302, a PWM control signal is output to a BUCK type PFC circuit according to the output voltage and output current of the rectifier unit and the output voltage of the composite filter unit, such as Figure 4 As shown, steps S401-S405 are included.

[0051] Step S401, respectively performing proportional transformation on the reference voltage and the output voltage of the composite filter unit, and comparing the proportional transformation results to obtain a first compensation deviation; performing an outer loop PI operation on the first compensation deviation to obtain a first compensation output.

[0052] Step S402, after the output voltage of the rectifier unit is proportionally transformed once, it is input into a multiplier with the first compensation output to obtain a first current reference item; and after the output voltage of the rectifier unit is proportionally transformed once, it is proportionally transformed again to obtain a current reference feedforward item.

[0053] Step S403, obtaining a reference current according to the first current reference item and the current reference feedforward item; Step S404, performing proportional conversion on the output current of the rectifying unit and comparing the proportional conversion with the reference current to obtain a second compensation deviation.

[0054] Step S405 , performing an inner loop PI operation on the second compensation deviation to obtain a compensation signal; and modulating the compensation signal to output a PWM control signal to the BUCK type PFC circuit.

[0055] like Figure 5 As shown, it is a schematic diagram of the principle of outputting a PWM control signal provided by the present invention.

[0056] Combine the following Figure 5 , steps S401-S405 in the embodiment of the present invention are described.

[0057] Specifically, during the PI operation control process, the double closed-loop controller completes the output of the compensation signal.

[0058] In step S401, the reference voltage The output voltage is measured by the voltage sensor. After proportional transformation, the first compensation deviation is obtained by comparison. , the first compensation deviation After PI operation, the output of the voltage outer loop controller is obtained.

[0059] Specifically, the system needs to first sample the instantaneous output voltage And compensate it, the role of compensation is to provide more adjustment margin for the system. Calculate the given reference voltage The instantaneous output voltage The first compensation deviation , the formula is as follows:

[0060] As the input of the voltage outer loop controller, the output of the voltage outer loop controller is calculated as follows:

[0061] in, is the outer ring proportional coefficient, is the outer loop integral coefficient, and the calculated first compensation output As one of the inputs for subsequent calculations.

[0062] In step S402, the output voltage of the rectifier unit is After a proportional conversion, the first compensation output The first current reference term is input into the multiplier together, and the formula of the first current reference term is as follows:

[0063] Then, the output voltage of the rectifier unit After performing a proportional transformation, perform a proportional transformation again to obtain the current reference feedforward term .

[0064] In step S403, the reference input of the current inner loop controller includes two parts: a first current reference term and a current reference feedforward term. The specific formula is as follows:

[0065] In the formula is the reference input of the current inner loop controller, i.e. the reference current, That is the feedforward term designed by the present invention. By introducing the feedforward term, a new regulating variable is introduced for regulating the system current THD, further improving the system's ability to suppress current THD.

[0066] In step S404, the output current of the rectifier unit is sampled. And compensate it, the role of compensation is to provide more regulation margin for the system; the output current of the rectifier unit After proportional conversion, it is compared with the reference current Compare and get the second compensation deviation , the formula is as follows:

[0067] In step S405, As the input of the current inner loop controller, the output of the current inner loop controller is calculated according to the following formula to obtain the compensation signal .

[0068]

[0069] In the formula, is the inner ring proportional coefficient, is the inner loop integral coefficient, the calculated signal As the input of PWM modulation, it forms PWM through the modulation link, and then is amplified by PWM drive and sent to the BUCK type PFC circuit.

[0070] The following is a description of an embodiment of a simulation process of a control method for a BUCK type PFC circuit in the present invention.

[0071] For single-phase AC220V input, the output voltage of the BUCK type PFC circuit is set to DC 90V, the power factor is required to be above 0.98, and the current THD is required to be below 8%.

[0072] The parameters of the Buck PFC device voltage outer loop PI regulation law are designed as follows: Outer loop proportional coefficient , the outer loop integral coefficient .

[0073] The parameters of the inner loop PI regulation law of the Buck PFC device are designed as follows: Inner loop proportional coefficient , the inner loop integral coefficient .

[0074] Other compensation parameters of Buck PFC device are designed as follows: Adjustment speed coefficient , , , and .

[0075] The load setting of the Buck PFC device is .

[0076] The control system of the BUCK type PFC circuit is examined when the single-phase AC220V input is input, the system's input voltage and current waveforms, the output voltage waveform, and the waveform of the output current after rectification.

[0077] Figure 6This is a curve diagram of the voltage and current of the AC input in the control system of the BUCK type PFC circuit. The light-colored curve is the AC voltage curve, which is reduced by 10 times for the convenience of phase comparison with the current curve. The dark-colored curve is the current waveform curve. It can be clearly seen from the figure that the phase of the AC current waveform tracks the phase waveform of the AC voltage very well, and the current waveform has no obvious distortion. The power factor is 0.985 and the current THD is 6.6%, achieving the purpose of high power factor and low current THD.

[0078] like Figure 7 As shown, the control system of the BUCK type PFC circuit provided by the present invention, the curve diagram of the output current after rectification, from Figure 7 It can be seen that the current waveform has no distortion, which fully demonstrates the effectiveness of the combined filtering method proposed in the present invention.

[0079] In the embodiment of the present invention, a control system of a BUCK type PFC circuit provided by the present invention is compared with a common BUCK type PFC circuit.

[0080] The power factor of the BUCK type PFC circuit provided by the present invention is 0.985, and the current THD is 6.6%, achieving the purpose of high power factor and low current THD. Under the same other conditions, the power factor of the ordinary BUCK type PFC circuit is 0.97, and the current THD is 10.1%.

[0081] Figure 8 An example of a physical structure diagram of an electronic device is shown in FIG. Figure 8 As shown, the electronic device may include: a processor 810, a communication interface 820, a memory 830 and a communication bus 840, wherein the processor 810, the communication interface 820 and the memory 830 communicate with each other through the communication bus 840. The processor 810 may call the logic instructions in the memory 830 to execute the control method of the BUCK type PFC circuit, including the following steps: The output voltage and output current of the rectifier unit and the output voltage of the composite filter unit are collected.

[0082] According to the output voltage and output current of the rectifier unit and the output voltage of the composite filter unit, a PWM control signal is output to the BUCK type PFC circuit, and the PWM control signal is used to control the shutdown of the BUCK type PFC circuit.

[0083] In addition, the logic instructions in the above-mentioned memory 830 can be implemented in the form of a software functional unit and can be stored in a computer-readable storage medium when it is sold or used as an independent product. Based on this understanding, the technical solution of the present invention is essentially or the part that contributes to the prior art or the part of the technical solution can be embodied in the form of a software product, and the computer software product is stored in a storage medium, including a number of instructions to enable a computer device (which can be a personal computer, a server, or a network device, etc.) to perform all or part of the steps of the method described in each embodiment of the present invention. The aforementioned storage medium includes: U disk, mobile hard disk, read-only memory (ROM, Read-Only Memory), random access memory (RAM, Random Access Memory), disk or optical disk and other media that can store program codes.

[0084] On the other hand, the present invention further provides a computer program product, the computer program product comprising a computer program, the computer program can be stored in a non-transitory computer-readable storage medium, and when the computer program is executed by a processor, the computer can execute the control method of the BUCK type PFC circuit provided by the above methods, including the following steps: The output voltage and output current of the rectifier unit and the output voltage of the composite filter unit are collected.

[0085] According to the output voltage and output current of the rectifier unit and the output voltage of the composite filter unit, a PWM control signal is output to the BUCK type PFC circuit. The PWM control signal is used to control the on and off of the switch tube in the BUCK type PFC circuit.

[0086] In another aspect, the present invention further provides a non-transitory computer-readable storage medium having a computer program stored thereon, and when the computer program is executed by a processor, the control method of the BUCK type PFC circuit provided by the above methods is implemented, comprising the following steps: The output voltage and output current of the rectifier unit and the output voltage of the composite filter unit are collected.

[0087] According to the output voltage and output current of the rectifier unit and the output voltage of the composite filter unit, a PWM control signal is output to the BUCK type PFC circuit. The PWM control signal is used to control the on and off of the switch tube in the BUCK type PFC circuit.

[0088] The device embodiments described above are merely illustrative, wherein the units described as separate components may or may not be physically separated, and the components displayed as units may or may not be physical units, that is, they may be located in one place, or they may be distributed on multiple network units. Some or all of the modules may be selected according to actual needs to achieve the purpose of the scheme of this embodiment. Those of ordinary skill in the art may understand and implement it without creative effort.

[0089] Through the description of the above implementation methods, those skilled in the art can clearly understand that each implementation method can be implemented by means of software plus a necessary general hardware platform, and of course, can also be implemented by hardware. Based on this understanding, the above technical solution is essentially or the part that contributes to the prior art can be embodied in the form of a software product, and the computer software product can be stored in a computer-readable storage medium, such as ROM / RAM, a disk, an optical disk, etc., including a number of instructions for a computer device (which can be a personal computer, a server, or a network device, etc.) to execute the methods described in each embodiment or some parts of the embodiments.

[0090] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A control system for a BUCK type PFC circuit, characterized in that: include: A rectifier unit, a first filter unit, a BUCK type PFC circuit, a composite filter unit and a control unit; One side of the rectifying unit is input with an AC voltage, and the other side is coupled with one side of the first filtering unit; The other side of the first filter unit is coupled to one side of the BUCK type PFC circuit; The other side of the BUCK type PFC circuit is coupled to one side of the composite filter unit; The other side of the composite filter unit is used to couple with the load end; The control unit is used to collect the output voltage and output current of the rectifier unit and the output voltage of the composite filter unit; and is also used to output a PWM control signal to the BUCK type PFC circuit according to the output voltage and output current of the rectifier unit and the output voltage of the composite filter unit, wherein the PWM control signal is used to control the on and off of the switch tube in the BUCK type PFC circuit.

2. The control system of the BUCK type PFC circuit according to claim 1, characterized in that: The first filtering unit is a CLC filter.

3. The control system of the BUCK type PFC circuit according to claim 1, characterized in that: Also includes a capacitor, one side of the capacitor is coupled to one side of the BUCK type PFC circuit, and the other side of the capacitor is grounded; The capacitor is connected in parallel with the BUCK type PFC circuit to form a second filtering unit.

4. The control system of the BUCK type PFC circuit according to claim 1, characterized in that: The rectifying unit is composed of a plurality of rectifying diodes.

5. The control system of the BUCK type PFC circuit according to any one of claims 1 to 4, characterized in that: The CLC filter is used to filter the higher harmonics in the BUCK type PFC circuit.

6. A control method for a BUCK type PFC circuit, characterized in that: A control system for a BUCK type PFC circuit as claimed in any one of claims 1 to 5, comprising: Collecting the output voltage and output current of the rectifying unit and the output voltage of the composite filtering unit; According to the output voltage and output current of the rectifier unit and the output voltage of the composite filter unit, a PWM control signal is output to the BUCK type PFC circuit, and the PWM control signal is used to control the on and off of the switch tube in the BUCK type PFC circuit.

7. The control method of the BUCK type PFC circuit according to claim 1, characterized in that: The step of outputting a PWM control signal to the BUCK type PFC circuit according to the output voltage and output current of the rectifier unit and the output voltage of the composite filter unit comprises: Performing proportional transformation on the reference voltage and the output voltage of the composite filter unit respectively, and comparing the proportional transformation results to obtain a first compensation deviation; performing an outer loop PI operation on the first compensation deviation to obtain a first compensation output; After the output voltage of the rectifier unit is proportionally transformed once, the output voltage is input into a multiplier with the first compensation output to obtain a first current reference item; and after the output voltage of the rectifier unit is proportionally transformed once, the output voltage is proportionally transformed again to obtain a current reference feedforward item; Obtaining a reference current according to the first current reference term and the current reference feedforward term; The output current of the rectifying unit is proportionally converted and compared with the reference current to obtain a second compensation deviation; An inner loop PI operation is performed on the second compensation deviation to obtain a compensation signal; and the compensation signal is modulated to output a PWM control signal to the BUCK type PFC circuit.

8. An electronic device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein: When the processor executes the computer program, the control method of the BUCK type PFC circuit according to any one of claims 6 to 7 is implemented.

9. A non-transitory computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the control method of the BUCK type PFC circuit according to any one of claims 6 to 7 is implemented.

10. A computer program product, comprising a computer program, characterized in that When the computer program is executed by a processor, the control method of the BUCK type PFC circuit according to any one of claims 6 to 7 is implemented.

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