Control method, control device, storage medium, computer program product and refrigeration equipment of pfc circuit

Abstract

This invention discloses a control method, control device, storage medium, computer program product, and refrigeration equipment for a PFC circuit, relating to the field of refrigeration equipment technology. First, the phase of the input voltage at the power input terminal is obtained; the rate of change of the input current is determined based on the correspondence between the input voltage phase and the input current phase at the power input terminal; then, based on the phase of the input voltage and the rate of change of the input current, the differential compensation gain value required to compensate the input current is determined; a PWM control signal is generated and output to the PFC switching device based on the differential compensation gain value to adjust the input current of the PFC circuit. The differential compensation gain value is used in PFC current detection. The detected PFC current and PFC voltage control loop generate a PWM wave through a specific software algorithm to control the switching of the IBGT device in the PFC circuit, so that the PFC input current waveform follows the input voltage waveform. This invention aims to improve the accuracy of PFC current detection, reduce harmonics and device heating during refrigeration equipment operation, and improve operating efficiency.

Description

Technical Field

[0001] This invention relates to the field of refrigeration equipment technology, and in particular to a control method, control device, storage medium, computer program product, and refrigeration equipment for a PFC circuit. Background Technology

[0002] In variable frequency air conditioner outdoor units, the PFC (Power Factor Correction) circuit is a key component for improving system efficiency and reducing harmonic distortion. To ensure that the input current and input voltage remain in phase, PFC current detection and control are essential. However, in practical applications, PFC current detection faces several challenges. For example, noise interference generated during the switching process of the compressor's IPM module, the fan's IPM module, and the switching power supply module affects the accuracy of PFC current detection. To reduce this noise interference, PFC current detection typically employs hardware and software low-pass filtering. However, low-pass filtering causes current phase lag, resulting in a time delay between the detected current signal and the actual current signal, thus affecting the accuracy of PFC current control. Therefore, PFC current detection typically uses differential compensation technology, compensating for the differential term of the current signal to reduce phase lag. Existing differential compensation schemes have a differential compensation gain that is proportional to the PFC current magnitude. That is, the compensation gain is maximum when the current change is minimal, which easily causes resonance, increases current harmonics, and reduces equipment operating efficiency. Summary of the Invention

[0003] The main objective of this invention is to propose a control method, control device, storage medium, computer program product, and refrigeration equipment for a PFC circuit, aiming to improve the accuracy of PFC current detection, reduce harmonics and device heating during the operation of the refrigeration equipment, and improve operating efficiency.

[0004] To achieve the above objectives, this invention proposes a control method for a PFC circuit, wherein the PFC circuit includes a power input terminal and a PFC switching device, and the control method for the PFC circuit includes:

[0005] Obtain the phase of the input voltage at the power input terminal;

[0006] The rate of change of the input current is determined based on the correspondence between the phase of the input voltage and the phase of the input current at the power input terminal;

[0007] Based on the phase of the input voltage and the rate of change of the input current, determine the differential compensation gain value required to compensate for the input current;

[0008] The PFC switching device generates and outputs a corresponding PWM control signal based on the differential compensation gain value to adjust the input current of the PFC circuit.

[0009] In one embodiment, determining the differential compensation gain value required to compensate the input current based on the phase of the input voltage and the rate of change of the input current specifically includes:

[0010] Based on the preset correspondence between the differential compensation phase interval and the differential compensation gain value, the phase of the input voltage is sequentially matched with multiple differential compensation phase intervals;

[0011] When the phase of the input voltage successfully matches one of the plurality of differential compensation phase intervals, the differential compensation gain value corresponding to the phase of the input voltage is determined.

[0012] In one embodiment, prior to the step of acquiring the phase of the input voltage at the power input terminal, the control method of the PFC circuit further includes:

[0013] Once the PFC circuit meets the activation conditions, control the PFC circuit to start working.

[0014] In one embodiment, the activation condition specifically includes:

[0015] The input current reaches a preset current threshold.

[0016] In one embodiment, generating and outputting a corresponding PWM control signal to the PFC switching device based on the differential compensation gain value specifically includes:

[0017] Calculate the differential compensation value of the input current based on the phase of the input voltage and the differential compensation gain value;

[0018] A corresponding PWM control signal is generated based on the input current value and the differential compensation value, and output to the PFC switching device.

[0019] In one embodiment, the control method for the PFC circuit further includes:

[0020] Obtain the bus voltage of the power supply circuit;

[0021] The PWM control signal is adjusted according to the relationship between the bus voltage and the preset voltage range to control the PFC switching device to turn on / off, so as to keep the bus voltage within the preset voltage range.

[0022] The present invention also proposes a control device comprising: a memory, a processor, and a computer program stored in the memory and executable on the processor, the computer program being configured to implement the steps of the control method for the PFC circuit as described in any of the preceding claims.

[0023] The present invention also proposes a storage medium, which is a computer-readable storage medium, on which a computer program is stored, and when the computer program is executed by a processor, it implements the steps of the control method of the PFC circuit as described in any of the preceding claims.

[0024] The present invention also proposes a computer program product comprising a computer program that, when executed by a processor, implements the steps of the control method for the PFC circuit as described in any of the preceding claims.

[0025] The present invention also proposes a refrigeration device, which includes the control device described above.

[0026] This invention proposes a control method for a PFC circuit. The PFC circuit includes a power input terminal and a PFC switching device. In the control method, the phase of the input voltage at the power input terminal is first obtained; then, the rate of change of the input current is determined according to the correspondence between the phase of the input voltage and the phase of the input current at the power input terminal; next, the differential compensation gain value required to compensate the input current is determined according to the phase of the input voltage and the rate of change of the input current; finally, a corresponding PWM control signal is generated and output to the PFC switching device according to the differential compensation gain value to adjust the input current of the PFC circuit.

[0027] In practical applications, the rate of change of input current can be determined based on the phase of the input voltage, and the differential compensation gain can be adjusted in real time according to the rate of change of input current. This effectively improves the problem in existing solutions where the PFC current change is minimized, but the differential compensation gain is maximized, meaning that the smallest current change uses the largest differential compensation gain, amplifying noise. This improves the accuracy of PFC current detection, reduces harmonics and device heating during the operation of the cooling equipment without increasing the cost of the outdoor unit, and improves operating efficiency. Attached Figure Description

[0028] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art 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 the structures shown in these drawings without creative effort.

[0029] Figure 1 This is a flowchart of an embodiment of the control method for the PFC circuit of the present invention;

[0030] Figure 2 This is a flowchart of another embodiment of the control method for the PFC circuit of the present invention;

[0031] Figure 3 This is a flowchart of another embodiment of the control method for the PFC circuit of the present invention;

[0032] Figure 4 This is a flowchart of another embodiment of the control method for the PFC circuit of the present invention;

[0033] Figure 5 This is a specific circuit diagram of an embodiment of a prior art power supply circuit;

[0034] Figure 6 This is a detailed circuit diagram of an embodiment of the power supply circuit of the present invention;

[0035] Figure 7 This is a flowchart of an embodiment of the control method for the PFC circuit of the present invention;

[0036] Figure 8 This is a waveform diagram of the input voltage and input current.

[0037] The realization of the objective, functional features and advantages of the present invention will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0038] 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 a part of the embodiments of the present invention, and not all of the 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 the present invention.

[0039] It should be noted that step designations such as S100 and S200 are used in this document for the purpose of more clearly and concisely describing the corresponding content, and do not constitute a substantial limitation on the order. In specific implementation, those skilled in the art may execute S200 first and then S100, etc., but these should all be within the protection scope of this application.

[0040] In variable frequency air conditioner outdoor units, the PFC (Power Factor Correction) circuit is a key component for improving system efficiency and reducing harmonic distortion. To ensure that the input current and input voltage remain in phase, PFC current detection and control are essential. However, in practical applications, PFC current detection faces multiple challenges, particularly interference from various noise sources and phase lag caused by low-pass filtering. For example, the compressor's IPM module, the fan's IPM module, and the switching power supply module generate noise interference during switching, affecting the accuracy of PFC current detection. To reduce this noise interference, PFC current detection typically employs hardware and software low-pass filtering. However, low-pass filtering causes current phase lag, resulting in a time delay between the detected current signal and the actual current signal, thus affecting the accuracy of PFC current control. Therefore, PFC current detection typically uses differential compensation technology, compensating for the differential term of the current signal to reduce phase lag. Existing differential compensation schemes have a differential compensation gain proportional to the PFC current. However, when the current change is minimal, the compensation gain is at its maximum, which can easily cause resonance and increase harmonic distortion.

[0041] refer to Figure 5 , Figure 5 This describes the power supply circuit of a refrigeration device in the prior art. BD is a rectifier circuit, used to rectify the AC power output to the power input terminal of the PFC circuit. The PFC circuit ensures that the input current and input voltage remain in phase, improving the power factor, reducing harmonic distortion, and providing a stable DC bus voltage for the downstream inverter. IPM is the intelligent power module for the fan or compressor of the refrigeration device. The current sampling circuit collects the input current of the PFC circuit and outputs the current sampling signal to the MCU. The MCU then applies the differentially compensated signal to the PFC current detection, generating a PWM wave to control the switching state of the IGBT devices, thereby adjusting the bus voltage and PFC input current. The overcurrent protection circuit outputs a corresponding overcurrent protection signal to the MCU when the input current of the PFC circuit exceeds a preset safe current threshold, allowing the MCU to control the switching devices to the off state based on the overcurrent detection signal. However, currently, the differential compensation gain of the PFC current detection is proportional to the PFC input current. When the input current is at its maximum, the PFC current change rate (di / dt) is zero, but the differential compensation gain is at its maximum. This amplifies noise, easily causes resonance, and increases harmonics. In actual operation, a high level of harmonics in the outdoor unit of the air conditioner leads to increased heating of the electrical components and decreased efficiency. Furthermore, the differential compensation gain in existing solutions is determined as a compromise empirical value based on experimental data. This reduces the effectiveness of differential compensation during PFC current detection, affecting the accuracy of current detection.

[0042] Therefore, this invention proposes a control method for a PFC circuit, referring to... Figure 1 The PFC circuit includes a power input terminal and a PFC switching device, and the control method of the PFC circuit includes:

[0043] Step S100: Obtain the phase of the input voltage at the power input terminal;

[0044] Step S200: Determine the rate of change of the input current based on the correspondence between the phase of the input voltage and the phase of the input current at the power input terminal;

[0045] Step S300: Determine the differential compensation gain value required to compensate for the input current based on the phase of the input voltage and the rate of change of the input current;

[0046] Step S400: Generate and output a corresponding PWM control signal to the PFC switching device according to the differential compensation gain value, so as to adjust the input current of the PFC circuit.

[0047] In this embodiment, the control method of the PFC circuit of the present invention can be applied to the control device of a refrigeration equipment. For example, the control device integrates a memory for storing the control program of the PFC circuit of the present invention, and a processor for executing the control program of the PFC circuit of the present invention. The control device can be implemented using a main controller, such as an MCU, DSP (Digital Signal Processor), FPGA (Field Programmable Gate Array), PLC, or SOC (System on Chip). Refrigeration equipment includes refrigerators, air conditioners, freezers, etc.

[0048] In this embodiment, the control device includes a main controller, a voltage sampling circuit, and a phase circuit. The voltage sampling circuit can be implemented using a voltage transformer, a Hall effect sensor, etc. The phase circuit can be implemented using a phase-locked loop (PLL) circuit, a phase-locked amplifier, etc. The voltage sampling circuit acquires the input voltage at the power input terminal and outputs it to the phase circuit. For example, it calculates the real-time phase of the input voltage at the power input terminal using a software PPL algorithm to obtain the input voltage phase at the power input terminal and outputs it to the main controller. The main controller determines the rate of change of the input current based on the correspondence between the input voltage phase and the input current phase at the power input terminal. It is understood that the main function of the PFC (Power Factor Correction) circuit is to make the phase of the input current and the input voltage as consistent as possible, thereby reducing reactive power waste and improving energy efficiency. Therefore, when the PFC circuit is working, the power factor can reach approximately 0.99 (close to 1), which means that after the PFC circuit is turned on, the phase difference between the input current and the input voltage is very small, almost in phase. Figure 8In this scenario, the waveform of the input current is very close to that of the input voltage, almost identical sine waves. It can be approximated that the phase of the input voltage corresponds one-to-one with the phase of the input current at the power input terminal. Therefore, the rate of change of the input current can be determined by monitoring the phase of the input voltage. Then, based on the phase of the input voltage and the rate of change of the input current, the differential compensation gain value required to compensate for the input current is determined. For example, researchers can create a lookup table of input current change rate and differential compensation gain value based on extensive experimental data and store it in the main controller's built-in memory. Thus, after determining the rate of change of the input current based on the input voltage phase, the main controller looks up the lookup table to determine the corresponding differential compensation gain value required to compensate for the input current. Finally, it generates and outputs the corresponding PWM control signal to the PFC switching device based on the differential compensation gain value to adjust the input current of the PFC circuit. For example, the differential compensation gain value and the phase of the input voltage are input to a multiplier to obtain the differential compensation value. The compensated input current value is then calculated based on the differential compensation value and the sampled input current value. Finally, based on the compensated input current value and the PFC voltage control loop, a corresponding PWM control signal is generated according to a preset software control algorithm to control the on / off state of the PFC switching devices (including IGBTs), thereby adjusting the input current of the PFC circuit. For example, the control device integrates a voltage detection circuit. This circuit detects the bus voltage and outputs a corresponding voltage detection signal to the main controller. The main controller determines the magnitude of the DC bus voltage based on the voltage detection signal. The control device generates a corresponding PWM control signal based on the input voltage, the compensated input current, and the DC bus voltage. That is, after obtaining the compensated input current value, the main controller combines the input voltage and the DC bus voltage according to a preset control algorithm to generate a corresponding PWM control signal for the PFC switching devices and calculates the duty cycle of the switching transistors. The duty cycle determines the proportion of the PFC switching transistors' on-time, thereby controlling the input current of the PFC circuit. In this way, the rate of change of the input current is determined by the phase of the input voltage, and the PWM control signal is adjusted in advance so that the input current follows the change of the input voltage more quickly, thereby improving the dynamic response and stability of the PFC circuit.

[0049] In practical applications, the rate of change of the input current can be determined based on the phase of the input voltage, and the differential compensation gain can be adjusted in real time according to the rate of change of the input current. This differential compensation gain value is then used in PFC current detection. Finally, the detected PFC current and PFC voltage control loop generate a PWM wave through a specific software algorithm to control the switching of the IBGT device in the PFC circuit, making the PFC input current waveform follow the input voltage waveform. This effectively improves upon the problem in related solutions where the PFC current change is minimized, but the differential compensation gain is maximized (i.e., the smallest current change uses the largest differential compensation gain, amplifying noise). Thus, the accuracy of PFC current detection is improved, and harmonics and heat generation during the operation of the refrigeration equipment are reduced without increasing the cost of the outdoor unit, thereby improving operating efficiency.

[0050] In one embodiment, reference Figure 2 Step S300 specifically includes:

[0051] Step S310: According to the preset correspondence between the differential compensation phase interval and the differential compensation gain value, the phase of the input voltage is matched with multiple differential compensation phase intervals in sequence;

[0052] Step S320: When the phase of the input voltage successfully matches one of the plurality of differential compensation phase intervals, determine the differential compensation gain value corresponding to the phase of the input voltage.

[0053] Based on the above embodiments, the control device can determine the input current change rate based on the phase of the input voltage at the power input terminal, and then determine the differential compensation gain value based on the phase of the input voltage and the input current change rate. This generates a corresponding PWM control signal to the PFC switching device (including IGBTs) to perform differential compensation on the input current of the PFC circuit, improving the accuracy of PFC current detection. Specifically, researchers can obtain the differential compensation gain value required for different input current change rates based on a large amount of experimental data, forming an input current change rate-differential compensation gain value lookup table, which is then stored in advance in the integrated memory within the control device. For example, different input voltage phases can be used as differential compensation phase intervals. Since the power factor can reach approximately 0.99 after the PFC circuit starts working, the input current and input voltage are essentially in phase. Therefore, the input current change rate can be determined based on the input voltage phase. Different differential compensation phase intervals correspond to different input current change rates, and each differential compensation phase interval corresponds to a differential compensation gain value. In this way, the control device can sequentially match the phase of the input voltage with multiple differential compensation phase intervals based on the preset correspondence between the differential compensation phase intervals and the differential compensation gain values. (Reference) Figure 7Assuming the differential compensation phase intervals include interval 1 (0° to 90°), interval 2 (90° to 180°), interval 3 (180° to 270°), and interval 4 (270° to 360°), it should be noted that the phase difference of each differential compensation phase interval can be set by the R&D personnel. Interval 1 corresponds to differential compensation gain H1, interval 2 to differential compensation gain H2, interval 3 to differential compensation gain H3, and interval 4 to differential compensation gain H4. The control device sequentially matches the phase of the input voltage at the power input terminal with multiple preset differential compensation phase intervals. When the phase of the input voltage successfully matches one of the multiple differential compensation phase intervals, the differential compensation gain value is determined. For example, when the phase of the input voltage is 45°, the differential compensation gain value is determined to be H1. When the phase of the input voltage is 275°, the control device will match the phase of the input voltage with intervals 1 to 4 in sequence, determine the differential compensation gain value H4, and then generate and output the corresponding PWM control signal to the PFC switching device to adjust the input current of the PFC circuit.

[0054] In practical applications, this invention can determine the slope of current change based on voltage phase. The differential compensation gain value is decreased when the current change rate is small and increased synchronously when the current change rate is large. That is, different differential compensation gain values ​​are used for different current change rates, and the corrected differential compensation value is applied to PFC current detection. Compared to existing technologies that use an empirical compromise value as the differential compensation gain value, and where the differential compensation gain value is proportional to the input current, leading to the use of the largest differential compensation gain for the smallest current change, causing resonance and increasing harmonics, the control method of this invention's PFC circuit can match the differential compensation gain value to the phase of the input voltage, improving the accuracy of PFC current detection and control.

[0055] In another embodiment of the present invention, before the step of obtaining the phase of the input voltage at the power input terminal, the control method of the PFC circuit further includes:

[0056] Once the PFC circuit meets the activation conditions, control the PFC circuit to start working.

[0057] The specific conditions for activation include:

[0058] The input current reaches a preset current threshold.

[0059] In this embodiment, the control device further includes a current sampling circuit for acquiring the input current of the PFC circuit and outputting it to the main controller. The current sampling circuit can be implemented using a shunt, current transformer, or the like.

[0060] Based on the above embodiments, the main function of the PFC circuit is to improve the power factor, ensuring that the input current and input voltage are in phase, thus reducing harmonic distortion. After the PFC circuit is operational, the power factor can typically reach around 0.99, meaning that the input current and input voltage are almost perfectly in phase. When the input current and input voltage are in phase, the rate of change of the input current can be accurately determined. That is, when the power factor is close to 1, the rate of change of the input current can be directly determined from the phase of the input voltage, thereby reducing errors.

[0061] In this embodiment, the refrigeration equipment includes an air conditioner. After the outdoor unit of the inverter air conditioner is powered on, the control device performs initialization operations, such as reset and parameter configuration. The IPM (Intelligent Power Module) of the compressor and fan starts working, starting the compressor and fan. The compressor and fan typically start operating at a low frequency to reduce the inrush current during startup. The control device gradually increases the operating frequency of the compressor based on the indoor temperature and set parameters. As the compressor operating frequency increases, the compressor load gradually increases, and the required current also gradually increases. The fan speed increases with the increase in compressor frequency, and the required current also increases accordingly. When the outdoor unit current reaches the activation condition of the PFC circuit, the PFC circuit is controlled to operate. It should be noted that the activation condition of the PFC circuit is set by the R&D personnel according to actual needs to ensure that the PFC circuit is activated at the appropriate time to improve the power factor and efficiency of the system. In this embodiment, the activation condition of the PFC circuit is set to: the input current reaches a preset current threshold.

[0062] Specifically, when the main controller MCU in the control device determines that the input current has reached the preset current threshold based on the current sampling signal output by the current sampling circuit, it determines that the PFC circuit meets the activation conditions and immediately starts the PFC circuit. The voltage sampling circuit collects the input voltage in real time and outputs the real-time phase of the voltage through a software algorithm phase-locked loop (PLL circuit). The main controller sequentially matches the input voltage phase with multiple differential compensation phase intervals. Since the power factor can reach about 0.99 after the PFC function is enabled, the input current and input voltage are basically in phase. At this time, the current change rate can be judged based on the voltage phase to determine the differential compensation gain value corresponding to the phase of the input voltage. When the current change rate is small, the differential compensation gain value is reduced; when the current change rate is large, the differential compensation gain value is increased synchronously. Finally, the compensated PFC current and PFC voltage control loop work together to generate the corresponding PWM control signal to the PFC switching device to adjust the PFC input current. For example, the differential compensation gain value and the phase of the input voltage are input to a multiplier to obtain the differential compensation value. The compensated input current value is calculated based on the differential compensation value and the sampled input current value. Then, based on the compensated input current value and the PFC voltage control loop, a corresponding PWM control signal is generated to control the conduction / disconnection of PFC switching devices (including IGBTs), thereby realizing the adjustment of the input current of the PFC circuit.

[0063] By determining whether the PFC circuit meets the activation conditions before acquiring the input voltage phase at the power input terminal, and activating the PFC circuit when the conditions are met, it is possible to ensure that the PFC circuit starts at the appropriate time, thereby improving the power factor and efficiency of the refrigeration system. After the PFC circuit is activated, the power factor can reach approximately 0.99, and the input current and input voltage are almost perfectly in phase. The rate of change of the input current can be accurately determined based on the phase of the input voltage, reducing errors. This enhances the stability and control precision of the refrigeration system.

[0064] In another embodiment, reference Figure 3 Step S400 specifically includes:

[0065] Step S410: Calculate the differential compensation value of the input current based on the phase of the input voltage and the differential compensation gain value;

[0066] Step S410: Generate a corresponding PWM control signal based on the input current value and the differential compensation value, and output it to the PFC switching device.

[0067] Based on the above embodiments, after the outdoor unit of the inverter air conditioner is powered on, the compressor and fan start. As the compressor's operating frequency increases, the outdoor unit current increases, reaching the PFC activation condition, and the PFC circuit operates. (Reference) Figure 6The diagram below shows the specific circuit diagram of the power supply circuit of this invention, which includes a PFC circuit. A voltage sampling circuit continuously monitors the input voltage of the PFC circuit. The main controller receives the voltage sampling signal output from the voltage sampling circuit, calculates the phase of the input voltage using a phase-locked loop algorithm, and then sequentially matches the phase of the input voltage with multiple differential compensation phase intervals to determine the differential compensation gain value H corresponding to the phase of the input voltage. Based on the phase of the input voltage and the differential compensation gain value, the differential compensation value of the input current is calculated. Finally, based on the input current value (current sampling value) corresponding to the current sampling signal output from the current sampling circuit and the differential compensation value, a corresponding PWM control signal is generated and output to the PFC switching device.

[0068] refer to Figure 7 The phase and differential compensation gain values ​​of the input voltage are output to the multiplier, respectively. After multiplication, the corresponding differential compensation value is output. Then, the current value corresponding to the current sampling signal output by the current sampling circuit is calculated with the differential compensation value according to a preset calculation formula to obtain the actual current value, and a corresponding PWM control signal is generated to the PFC switching device. The preset calculation rules are set in advance by the R&D personnel. In this embodiment, the preset calculation formula is:

[0069] I2 = I1 * (1 + β);

[0070] Where I2 is the actual current value, I1 is the current sample value, and β is the differential compensation value.

[0071] In practical applications, differential compensation improves the accuracy of PFC current detection, making the detected current waveform closer to the actual current waveform. More accurate current detection means the PFC current loop can more precisely control the input current, keeping it consistent with the input voltage, improving the power factor, and reducing harmonics. This improves the accuracy of PFC current detection and control, reducing harmonics and heat generation during refrigeration equipment operation without increasing outdoor unit costs, thus improving operating efficiency.

[0072] In refrigeration equipment, especially inverter air conditioner outdoor units, bus voltage control is a crucial factor in ensuring the stable and efficient operation of the refrigeration system. Through voltage and current detection, control algorithms, and protection mechanisms, bus voltage can be effectively controlled, improving the stability and efficiency of the refrigeration system, optimizing dynamic response, meeting regulatory requirements, and ensuring the product's market competitiveness.

[0073] In one embodiment of the present invention, reference is made to... Figure 4 The control method for the PFC circuit further includes:

[0074] Step S500: Obtain the bus voltage of the power supply circuit;

[0075] Step S600: Adjust the PWM control signal according to the relationship between the bus voltage and the preset voltage range, and control the PFC switching device to turn on / off, so as to control the bus voltage within the preset voltage range.

[0076] In this embodiment, the control device integrates a voltage detection circuit. This circuit detects the bus voltage and outputs a corresponding voltage detection signal to the main controller. The main controller determines the bus voltage based on the voltage detection signal and outputs a corresponding PWM control signal to the PFC switching device. This controls the PFC switching device to turn on / off with the duty cycle corresponding to the PWM control signal, ensuring the bus voltage remains within a preset voltage range. The voltage detection circuit can be implemented using a Hall sensor, a capacitive voltage sensor, or a resistive voltage divider. The preset voltage range is pre-set by the developers. For example, when the bus voltage is less than the preset range, the main controller increases the duty cycle of the PWM control signal, increasing the on-time of the PFC switching device, thereby increasing the input current and raising the bus voltage. The main controller MCU continuously monitors the bus voltage until it returns to the preset voltage range. Conversely, when the bus voltage is greater than the preset range, the main controller decreases the duty cycle of the PWM control signal, reducing the on-time of the PFC switching device, thereby reducing the input current and lowering the bus voltage until it falls back to the preset voltage range. When the bus voltage is within the preset voltage range, the duty cycle of the PWM control signal remains unchanged to maintain the stability of the bus voltage.

[0077] Based on the above embodiments, the control method of the PFC circuit of the present invention determines the rate of change of the input current based on the phase of the input voltage, takes different differential compensation gain values ​​for different current change rates, and applies the corrected differential compensation values ​​to the PFC current detection, thereby adjusting the input current of the PFC circuit and improving the accuracy of PFC current detection and control. Changes in the input current affect the stability of the bus voltage. If the input current control is inaccurate, the bus voltage may fluctuate. It is understood that the PFC current loop and voltage control loop cooperate with each other. The PFC current loop ensures that the input current and input voltage are in phase by precisely controlling the input current, thereby reducing bus voltage fluctuations. The voltage control loop (including the detection circuit) adjusts the switching state of the PWM device according to the detected bus voltage, further stabilizing the bus voltage. In other words, differential compensation improves the accuracy of current detection, enabling the PFC circuit's current loop to control the input current more accurately. Precise current control reduces input current fluctuations, which in turn reduces bus voltage fluctuations.

[0078] In practical applications, after differential compensation of the PFC current detection using the control method of the PFC circuit of this invention, the voltage loop and voltage control loop of the PFC circuit will work together to apply to the PWM control signal. That is, the main controller outputs the corresponding PWM control signal based on the actual current value calculated by the current loop according to the input current value and the differential compensation value, and the bus voltage output by the voltage detection circuit, to control the IGBT switch and ensure the stability of the input current and the bus voltage.

[0079] The present invention also proposes a control device, the control device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, the computer program being configured to implement the steps of the control method for the PFC circuit described in any of the preceding claims.

[0080] It is worth noting that since the control device of the present invention is based on the control method of the PFC circuit described above, the embodiments of the control device of the present invention include all the technical solutions of all embodiments of the control method of the PFC circuit described above, and the technical effects achieved are exactly the same, so they will not be repeated here.

[0081] The present invention also proposes a storage medium, which is a computer-readable storage medium, on which a computer program is stored, and when the computer program is executed by a processor, it implements the steps of the control method of the PFC circuit described in any of the above claims.

[0082] It is worth noting that since the storage medium of the present invention is based on the control method of the PFC circuit described above, the embodiments of the storage medium of the present invention include all the technical solutions of all embodiments of the control method of the PFC circuit described above, and the technical effects achieved are exactly the same, so they will not be repeated here.

[0083] The present invention also proposes a computer program product, which includes a computer program that, when executed by a processor, implements the steps of the control method for the PFC circuit described in any of the above claims.

[0084] It is worth noting that since the computer program product of the present invention is based on the control method of the PFC circuit described above, the embodiments of the computer program product of the present invention include all the technical solutions of all embodiments of the control method of the PFC circuit described above, and the technical effects achieved are exactly the same, so they will not be repeated here.

[0085] The present invention also proposes a refrigeration device, which includes the control device described above.

[0086] It is worth noting that since the refrigeration equipment of the present invention includes the above-mentioned control device, the embodiments of the refrigeration equipment of the present invention include all the technical solutions of all the embodiments of the above-mentioned control device, and the technical effects achieved are exactly the same, so they will not be repeated here.

[0087] The above description is merely an optional embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent structural transformations made using the contents of the present invention's specification and drawings under the inventive concept of the present invention, or direct / indirect applications in other related technical fields, are included within the patent protection scope of the present invention.

Claims

1. A control method for a PFC circuit, characterized in that, The PFC circuit includes a power input terminal and a PFC switching device. The control method of the PFC circuit includes: Obtain the phase of the input voltage at the power input terminal; The rate of change of the input current is determined based on the correspondence between the phase of the input voltage and the phase of the input current at the power input terminal; Based on the phase of the input voltage and the rate of change of the input current, determine the differential compensation gain value required to compensate for the input current; The PFC switching device generates and outputs a corresponding PWM control signal based on the differential compensation gain value to adjust the input current of the PFC circuit.

2. The control method for the PFC circuit as described in claim 1, characterized in that, The step of determining the differential compensation gain value required to compensate for the input current based on the phase of the input voltage and the rate of change of the input current specifically includes: Based on the preset correspondence between the differential compensation phase interval and the differential compensation gain value, the phase of the input voltage is sequentially matched with multiple differential compensation phase intervals; When the phase of the input voltage successfully matches one of the plurality of differential compensation phase intervals, the differential compensation gain value corresponding to the phase of the input voltage is determined.

3. The control method for the PFC circuit as described in claim 1, characterized in that, Prior to the step of acquiring the phase of the input voltage at the power input terminal, the control method of the PFC circuit further includes: Once the PFC circuit meets the activation conditions, control the PFC circuit to start working.

4. The control method for the PFC circuit as described in claim 3, characterized in that, The specific activation conditions include: The input current reaches a preset current threshold.

5. The control method for the PFC circuit as described in claim 1, characterized in that, The step of generating and outputting a corresponding PWM control signal to the PFC switching device based on the differential compensation gain value specifically includes: Calculate the differential compensation value of the input current based on the phase of the input voltage and the differential compensation gain value; A corresponding PWM control signal is generated based on the input current value and the differential compensation value, and output to the PFC switching device.

6. The control method for the PFC circuit as described in claim 1, characterized in that, The control method for the PFC circuit also includes: Obtain the bus voltage of the power supply circuit; The PWM control signal is adjusted according to the relationship between the bus voltage and the preset voltage range to control the PFC switching device to turn on / off, so as to keep the bus voltage within the preset voltage range.

7. A control device, characterized in that, The control device includes: a memory, a processor, and a computer program stored in the memory and executable on the processor, the computer program being configured to implement the steps of the control method for the PFC circuit as described in any one of claims 1 to 6.

8. A storage medium, characterized in that, The storage medium is a computer-readable storage medium, on which a computer program is stored, and when the computer program is executed by a processor, it implements the steps of the control method for the PFC circuit as described in any one of claims 1 to 6.

9. A computer program product, characterized in that, The computer program product includes a computer program that, when executed by a processor, implements the steps of the control method for the PFC circuit as described in any one of claims 1 to 6.

10. A refrigeration device, characterized in that, The refrigeration equipment includes the control device as described in claim 7.

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