PFC circuit and control method thereof, storage medium, electrical equipment and air conditioner

Abstract

The invention discloses a PFC circuit and a control method thereof, a storage medium, electrical equipment and an air conditioner, the PFC circuit comprises a plurality of switch tubes in a parallel state, and the method comprises the following steps: obtaining an operation parameter of each switch tube in the plurality of switch tubes; determining whether a switch tube with abnormal temperature exists in the plurality of switch tubes according to the operation parameters; and adjusting the switching frequency of the switch tube with the abnormal temperature when the switch tube with the abnormal temperature exists in the plurality of switch tubes, so as to carry out temperature equalization on the plurality of switch tubes. Therefore, according to the method, the switch tube with the abnormal temperature is determined according to the operation parameter of each switch tube, and the switching frequency of the switch tube with the abnormal temperature is adjusted, so that the temperature of the switch tube is adjusted, the effect of balancing the temperature of the parallel switch tubes is achieved, the service life of the switch tube is prolonged, and the operation reliability of the PFC circuit is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of electrical equipment, and in particular to a control method of a PFC circuit, a computer-readable storage medium, a PFC circuit, an electrical equipment and an air conditioner. Background Art

[0002] When the PFC circuit uses multiple switching devices working in parallel, the temperature rise of the parallel switching tubes will be different during normal operation due to factors such as the different positions of the switching tubes in the PCB and differences in the switching tube production process. Long-term accumulation will easily cause the performance of the switching tubes with large temperature rise to degrade or even be damaged, thereby reducing the reliability of the product. Summary of the invention

[0003] The present invention aims to solve one of the technical problems in the related art to at least a certain extent. To this end, the first object of the present invention is to provide a control method for a PFC circuit, which determines the switch tube with abnormal temperature according to the operating parameters of each switch tube, and adjusts the switching frequency of the switch tube with abnormal temperature, thereby realizing temperature regulation of the switch tube, so as to achieve the effect of temperature balancing of the parallel switch tubes, improve the service life of the switch tube and the operating reliability of the PFC circuit.

[0004] A second object of the present invention is to provide a computer-readable storage medium.

[0005] The third objective of the present invention is to provide a PFC circuit.

[0006] A fourth objective of the present invention is to provide an electrical device.

[0007] A fifth object of the present invention is to provide an air conditioner.

[0008] To achieve the above-mentioned purpose, a first aspect of an embodiment of the present invention proposes a control method for a PFC circuit, wherein the PFC circuit includes a plurality of switch tubes in a parallel state, and the method includes: obtaining operating parameters of each of the plurality of switch tubes; determining whether there is a switch tube with abnormal temperature among the plurality of switch tubes according to the operating parameters; when there is a switch tube with abnormal temperature among the plurality of switch tubes, adjusting the switching frequency of the switch tube with abnormal temperature to balance the temperature of the plurality of switch tubes.

[0009] The PFC circuit according to the embodiment of the present invention includes a plurality of switch tubes in a parallel state. The control method of the PFC circuit first obtains the operating parameters of each of the plurality of switch tubes, and determines whether there is a switch tube with abnormal temperature among the plurality of switch tubes according to the operating parameters. When there is a switch tube with abnormal temperature among the plurality of switch tubes, the switching frequency of the switch tube with abnormal temperature is adjusted to balance the temperature of the plurality of switch tubes. Thus, the method determines the switch tube with abnormal temperature according to the operating parameters of each switch tube, and adjusts the switching frequency of the switch tube with abnormal temperature, thereby achieving temperature regulation of the switch tube, so as to achieve the effect of temperature balancing of the parallel switch tubes, and improve the service life of the switch tube and the operating reliability of the PFC circuit.

[0010] In addition, the control method of the PFC circuit according to the above embodiment of the present invention may also have the following additional technical features:

[0011] According to one embodiment of the present invention, determining whether there is a switch tube with temperature abnormality among multiple switch tubes based on operating parameters includes: when the difference between the operating parameters of any switch tube among the multiple switch tubes and the operating parameters of at least one other switch tube is greater than a preset difference, and the change rate of the operating parameters of any switch tube is less than or equal to the preset change rate, determining that there is a primary temperature abnormality in any switch tube; wherein the other switch tubes are switch tubes other than any switch tube among the multiple switch tubes; when the difference between the operating parameters of any switch tube and the operating parameters of at least one other switch tube is greater than a preset difference, and the change rate of the operating parameters of any switch tube is greater than the preset change rate, determining that there is a secondary temperature abnormality in any switch tube.

[0012] According to one embodiment of the present invention, the temperature abnormality includes primary temperature abnormality and secondary temperature abnormality, and the switching frequency of the switch tube with the temperature abnormality is adjusted to balance the temperature of multiple switch tubes, including: when the switch tube with the temperature abnormality is in the primary temperature abnormality, the switching frequency of the switch tube with the temperature abnormality is reduced and the switching frequency after the reduction is greater than zero; when the switch tube with the temperature abnormality is in the secondary temperature abnormality, the switching frequency of the switch tube with the temperature abnormality is reduced and the switching frequency after the reduction is zero.

[0013] According to one embodiment of the present invention, reducing the switching frequency of a switch tube with abnormal temperature includes: sealing a control signal of the switch tube with abnormal temperature at a preset time interval, wherein the preset time interval is an integer multiple of the switching period of the switch tube with abnormal temperature.

[0014] According to one embodiment of the present invention, when adjusting the switching frequency of a switch tube with abnormal temperature to balance the temperature of multiple switch tubes, the control method of the PFC circuit also includes: obtaining the working modes of the multiple switch tubes; and adjusting the switching frequency of the switch tube with normal temperature according to the working mode to keep the switching frequency of the PFC circuit unchanged.

[0015] According to one embodiment of the present invention, the switching frequency of the switch tube with normal temperature is adjusted according to the working mode, including: when the working mode is the synchronous on-off mode, the switching frequency of the switch tube with normal temperature is kept unchanged; when the working mode is the alternating on-off mode, at least one switch tube with normal temperature is controlled to be turned on when the control signal of the switch tube with abnormal temperature is sealed.

[0016] According to one embodiment of the present invention, when the switching frequency of a switch tube with abnormal temperature is adjusted to balance the temperature of multiple switch tubes, the control method of the PFC circuit also includes: when the operating parameter of any switch tube among the multiple switch tubes is greater than a preset protection parameter, controlling any switch tube to stop working to perform over-temperature protection on any switch tube, and controlling the switch tube without over-temperature protection to continue working.

[0017] According to an embodiment of the present invention, the operating parameter includes the temperature of the switch tube or the current flowing through the switch tube.

[0018] According to one embodiment of the present invention, after controlling any switch tube to stop working to perform over-temperature protection on any switch tube, the control method of the PFC circuit also includes: if the operating parameter of any switch tube is less than a preset recovery parameter, controlling any switch tube to work again, wherein the preset recovery parameter is less than the preset protection parameter.

[0019] According to one embodiment of the present invention, the control method of the PFC circuit also includes: in the process of controlling any switch tube to resume working, or before the operating parameter of any switch tube is less than a preset recovery parameter, if the operating parameter of the switch tube without over-temperature protection is greater than the preset protection parameter, then the switch tube without over-temperature protection is controlled to stop working.

[0020] To achieve the above object, a second aspect of the present invention provides a computer-readable storage medium on which a control program of a PFC circuit is stored. When the control program of the PFC circuit is executed by a processor, the control method of the PFC circuit is implemented.

[0021] According to the computer-readable storage medium of an embodiment of the present invention, the control method of the PFC circuit described above is implemented when the control program of the PFC circuit is executed by the processor. Based on the control method of the PFC circuit described above, the switch tube with abnormal temperature is determined according to the operating parameters of each switch tube, and the switching frequency of the switch tube with abnormal temperature is adjusted, thereby realizing temperature regulation of the switch tube, so as to achieve the effect of temperature balancing of the parallel switch tubes, and improve the service life of the switch tube and the operating reliability of the PFC circuit.

[0022] To achieve the above-mentioned purpose, a third aspect of the present invention proposes a PFC circuit, comprising: a plurality of switch tubes in a parallel state; an acquisition unit, used to acquire the operating parameters of each of the plurality of switch tubes; a determination unit, used to determine whether there is a switch tube with abnormal temperature among the plurality of switch tubes according to the operating parameters; and a control unit, used to adjust the switching frequency of the switch tube with abnormal temperature when there is a switch tube with abnormal temperature among the plurality of switch tubes, so as to balance the temperature of the plurality of switch tubes.

[0023] According to the PFC circuit of the embodiment of the present invention, the acquisition unit acquires the operating parameters of each of the multiple switch tubes, and the determination unit determines whether there is a switch tube with abnormal temperature among the multiple switch tubes according to the operating parameters. When there is a switch tube with abnormal temperature among the multiple switch tubes, the control unit adjusts the switching frequency of the switch tube with abnormal temperature to balance the temperature of the multiple switch tubes. Thus, the PFC circuit can determine the switch tube with abnormal temperature according to the operating parameters of each switch tube, and adjust the switching frequency of the switch tube with abnormal temperature, thereby realizing temperature regulation of the switch tube, so as to achieve the effect of temperature balance of the parallel switch tubes, and improve the service life of the switch tube and the operating reliability of the PFC circuit.

[0024] To achieve the above-mentioned object, a fourth aspect of the present invention provides an electrical device, including the above-mentioned PFC circuit.

[0025] The electrical equipment according to the embodiment of the present invention improves the operating reliability of the electrical equipment based on the above-mentioned PFC circuit.

[0026] To achieve the above-mentioned purpose, a fifth aspect of the present invention proposes an air conditioner, comprising a memory, a processor, and a control program for a PFC circuit stored in the memory and executable on the processor. When the processor executes the control program for the PFC circuit, the above-mentioned control method for the PFC circuit is implemented.

[0027] In the air conditioner according to the embodiment of the present invention, when the processor executes the control program of the PFC circuit, the control method of the PFC circuit is implemented. Based on the control method of the PFC circuit, the switch tube with abnormal temperature can be determined according to the operating parameters of each switch tube, and the switching frequency of the switch tube with abnormal temperature can be adjusted, thereby realizing temperature regulation of the switch tube, so as to achieve the effect of temperature balancing of the parallel switch tubes, and improve the service life of the switch tube and the operating reliability of the PFC circuit.

[0028] Additional aspects and advantages of the present invention will be given in part in the following description and in part will be obvious from the following description, or will be learned through practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 is a flow chart of a control method of a PFC circuit according to an embodiment of the present invention;

[0030] Figure 2 is a circuit diagram of a PFC circuit according to an embodiment of the present invention;

[0031] Figure 3 A schematic diagram of temperature monitoring of a switch tube according to an embodiment of the present invention;

[0032] Figure 4 The waveform of the switch tube in the synchronous on-off mode according to one embodiment of the present invention is shown in FIG. Figure 1 ;

[0033] Figure 5 The waveform of the switch tube in the synchronous on-off mode according to one embodiment of the present invention is shown in FIG. Figure 2 ;

[0034] Figure 6 The waveform of the switch tube in the synchronous on-off mode according to one embodiment of the present invention is shown in FIG. Figure 3 ;

[0035] Figure 7 The waveform of the switch tube in the alternating on-off mode according to one embodiment of the present invention is shown in FIG. Figure 1 ;

[0036] Figure 8 The waveform of the switch tube in the alternating on-off mode according to one embodiment of the present invention is shown in FIG. Figure 2 ;

[0037] Fig. 9 The waveform of the switch tube in the alternating on-off mode according to one embodiment of the present invention is shown in FIG. Figure 3 ;

[0038] Fig.10 is a flow chart of a control method of a PFC circuit according to a specific embodiment of the present invention;

[0039] Fig.11 is a flow chart of a control method of a PFC circuit according to another specific embodiment of the present invention;

[0040] Fig.12 is a block diagram of a PFC circuit according to an embodiment of the present invention;

[0041] Fig.13 is a block diagram of an electrical device according to an embodiment of the present invention;

[0042] Fig.14 FIG. 1 is a block diagram of an air conditioner according to an embodiment of the present invention. DETAILED DESCRIPTION

[0043] Embodiments of the present invention are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present invention, and should not be construed as limiting the present invention.

[0044] The following describes a control method for a PFC circuit, a computer-readable storage medium, a PFC circuit, an electrical device, and an air conditioner provided in embodiments of the present invention with reference to the accompanying drawings.

[0045] Figure 1 FIG. 4 is a flow chart of a control method of a PFC circuit according to an embodiment of the present invention.

[0046] In one embodiment of the present invention, the PFC circuit includes a plurality of switch tubes in parallel.

[0047] Specifically, the PFC circuit composed of multiple switch tubes in parallel may include a single-phase output PFC circuit and a multi-phase output PFC circuit. In the multi-phase output PFC circuit, the switch tubes arranged in parallel correspond to different output ports. Figure 2 For example, multiple switch tubes are set in parallel, corresponding to one output port. Figure 2 and Figure 3 , the working process of the PFC circuit is explained with examples.

[0048] The PFC circuit 10 includes an inductor L1, a diode D5, a first switch tube S1 and a second switch tube S2. The control ends of the first switch tube S1 and the second switch tube S2 are respectively connected to the first output end Vout1 and the second output end Vout2 of the controller 50. The controller 50 outputs a PWM (Pulse Width Modulation) driving signal through the first output end Vout1 and the second output end Vout2 to drive the switch tube to perform a corresponding switching action, that is, the first PWM driving signal output from the first output end Vout1 controls the conduction and disconnection of the first switch tube S1, and the second PWM driving signal output from the second output end Vout2 controls the conduction and disconnection of the second switch tube S2.

[0049] The controller 50 can control the first switch tube S1 and the second switch tube S2 to operate alternately at a preset frequency. For example, it can control multiple switch tubes in the PFC circuit to not be turned on at the same time, or control adjacent switch tubes in the PFC circuit to achieve partial overlap of the on-time. For example, the first PWM drive signal and the second PWM drive signal can be PWM waveforms with the same frequency, the same duty cycle, and different phases. Controlling the first switch tube S1 and the second switch tube S2 to work alternately can be: after the first switch tube S1 is switched to the off state, the second switch tube S2 is controlled to be turned on, and after the second switch tube S2 is switched from the on state to the off state, the first switch tube S1 is controlled to be turned on, and so on, to achieve the alternating on and off operation of the first switch tube S1 and the second switch tube S2. In this control method, the first switch tube S1 and the second switch tube S2 are controlled to work alternately at the same time. The switch tubes S2 do not conduct at the same time; or, after the first switch tube S1 is in the on state for t1 time, the second switch tube S2 is controlled to conduct, and after t2 time, the second switch tube S1 is switched to the off state, the second switch tube is continuously on for t3 time and then turned off, after the second switch tube is turned off for t4 time, the first switch tube S1 is controlled to switch to the on state, and so on, to achieve the alternating on and off operation of the first switch tube S1 and the second switch tube S2. In this control strategy, the first switch tube S1 and the second switch tube S2 are simultaneously turned on for t2 time. The above is only an example of the control method of alternating operation, which can be specifically limited according to actual conditions. In addition, the controller 50 can also control the first switch tube S1 and the second switch tube S2 to be turned on and off synchronously.

[0050] The control signals of the first switch tube S1 and the second switch tube S2 can be specifically set with corresponding parameters such as frequency and duty cycle according to actual requirements such as the power requirement of the PFC circuit and the operating parameter restrictions of the switch tube, and no limitation is made here.

[0051] In addition, Figure 2In the embodiment, the first switch tube S1 and the second switch tube S2 adopt NMOS (N-Metal-Oxide-Semiconductor, N-type metal-oxide-semiconductor) tubes, and the control terminals of the first switch tube S1 and the second switch tube S2 are gates g of the NMOS tubes, the gate g of the first switch tube S1 is connected to the first output terminal Vout1 of the controller 50, and the gate g of the second switch tube S2 is connected to the second output terminal Vout2 of the controller 50. After the drain d of the first switch tube S1 and the drain d of the second switch tube S2 are connected, they are connected to one end of the inductor L1 and the anode of the diode D5, and the source s of the first switch tube S1 and the source s of the second switch tube S2 are connected. When a high level is input to the control terminals of the first switch tube S1 and the second switch tube S2, the switch tubes are turned on, and when a low level is input to the control terminals of the first switch tube S1 and the second switch tube S2, the switch tubes are turned off.

[0052] Furthermore, Figure 2 A specific application scenario of the PFC circuit 10 is given. Specifically, the AC signal provided by the AC source AC is rectified and outputted through the rectifier bridge 20. The PFC circuit 10 performs power factor correction on the DC signal outputted by the rectifier bridge 20, and filters it through the bus electrolytic capacitor C1 to output a stable DC power to the inverter circuit 30, and outputs three-phase power through the inverter circuit 30 to drive the motor 40 to operate.

[0053] When multiple switch tubes work in parallel, each switch tube is subject to turn-on loss and turn-off loss, which easily generates heat accumulation, thereby causing overheating loss of the switch tube, resulting in abnormal operation of the PFC circuit, thereby reducing the operating reliability of the circuit. In order to solve the above technical problems, this application proposes a control method for a PFC circuit. Figure 2 Taking as an example, the PFC control method proposed in this application is described in detail.

[0054] See also Figure 1 As shown, the control method of the PFC circuit in the embodiment of the present invention may include:

[0055] S1, obtaining an operating parameter of each switch tube among a plurality of switch tubes;

[0056] S2, determining whether there is a switch tube with abnormal temperature among the multiple switch tubes according to the operating parameters;

[0057] S3, when there is a switch tube with abnormal temperature among the multiple switch tubes, adjusting the switching frequency of the switch tube with abnormal temperature to balance the temperatures of the multiple switch tubes.

[0058] The operating parameters of the switch tube are used to determine the temperature state of the switch tube. For example, the operating parameters can be directly the temperature of the switch tube. Since the current flowing through the switch tube and the temperature of the switch tube also have a corresponding relationship, that is, the current flowing through the switch tube increases and the temperature of the switch tube rises, the operating parameters can also be the current flowing through the switch tube, which is not limited here. Among them, the temperature of the switch tube can be obtained through the temperature sampling circuit arranged corresponding to the switch tube, and the current flowing through the switch tube can be detected by the current sampling circuit on the parallel branch where the switch tube is located. It can be understood that when the switch tube is turned on, the current sampling circuit performs current acquisition work.

[0059] The control method of the present application is described in detail below by taking the operating parameter of the switch tube as the temperature of the switch tube as an example.

[0060] Specifically, Figure 2 and Figure 3 For example, a PFC circuit includes two parallel first switch tubes S1 and second switch tubes S2, and a temperature sampling circuit 1 and a temperature sampling circuit 2 are respectively set corresponding to the first switch tube S1 and the second switch tube S2. The real-time temperature of the first switch tube S1 is obtained through the temperature sampling circuit 1 to realize the temperature monitoring of the first switch tube S1; the real-time temperature of the second switch tube S2 is obtained through the temperature sampling circuit 2 to realize the temperature monitoring of the second switch tube S2. For example, the temperature sampling circuit can be constructed based on a thermistor, and the temperature of the corresponding switch tube is obtained through a thermistor set close to the switch tube. Since the resistance of the thermistor changes with the temperature of the switch tube, the temperature sampling circuit can output a voltage signal that changes accordingly. Specifically, the temperature sampling circuit can be composed of a thermistor and a voltage divider resistor connected in series, wherein the thermistor is set close to the corresponding switch tube. When the temperature of the switch tube changes, the resistance of the thermistor changes, so that the voltage signal output by the over-temperature protection circuit also changes. The output end of the over-temperature protection circuit is connected to the AD (Analogue-to-Digital) port of the controller 50. The controller 50 determines the current temperature of the corresponding switch tube according to the voltage value of the voltage signal received by the AD port, and further determines whether the switch tube has a temperature abnormality.

[0061] like Figure 3As shown, the thermistor NTC1 in the temperature sampling circuit 1 is arranged close to the first switch tube S1 to monitor the temperature of the first switch tube S1; the thermistor NTC2 in the temperature sampling circuit 2 is arranged close to the second switch tube S2 to monitor the temperature of the second switch tube S2, thereby realizing the separate monitoring output of the temperature of each switch tube. The output end of the temperature sampling circuit 1 is connected to the input end Vin1 of the controller 50, and the output end of the temperature sampling circuit 2 is connected to the input end Vin2 of the controller 50. The controller 50 determines the temperature of the first switch tube S1 and the second switch tube S2 according to the voltage signal received at the input end, and further determines whether there is a switch tube with abnormal temperature according to the temperature of the first switch tube S1 and the second switch tube S2. Assuming that it is determined that the first switch tube S has abnormal temperature, the first PWM drive signal is parameter adjusted according to the temperature of the first switch tube S1, and the adjusted first PWM drive signal is output through the output end Vout1 to control the first switch tube S1. Specifically, the switching frequency of the first switch tube S1 can be adjusted by adjusting the carrier frequency corresponding to the first switch tube S1.

[0062] In addition, for the switch tube without temperature abnormality, that is, the second switch tube S2, the controller 50 can continue to control the second switch tube S2 according to the original second PWM drive signal, or adjust the parameters of the second PWM drive signal according to the working requirements of the PFC circuit, for example, keep the carrier frequency in the second PWM drive signal unchanged, adjust the signal duty cycle, etc., to meet different application scenarios, which are not limited here.

[0063] It should be noted that, in addition to adjusting the PWM drive signal according to the temperature of the switch tube, the controller 50 can also adjust the parameters of the two PWM drive signals according to working requirements, so as to ensure the working performance of the PFC circuit while meeting the temperature protection.

[0064] Furthermore, whether the temperature is abnormal can be determined by setting a preset temperature threshold. For example, the temperature of the first switch tube S1 is compared with the temperature of the second switch tube S2. If the temperature of the first switch tube S1 is greater than the temperature of the second switch tube S2, and the temperature difference exceeds the preset temperature threshold, it is determined that the temperature difference between the two switch tubes is too large, and the first switch tube S1 with a high temperature has a temperature abnormality. At this time, the switching frequency of the first switch tube S1 can be reduced to reduce the heat generated during the operation of the first switch tube S1, thereby achieving a cooling effect. The above embodiment determines whether the temperature is abnormal based on the difference between the two switch tubes. In addition, a temperature standard value can be set to determine whether the temperature of the switch tube is abnormal by the temperature difference between the temperature of each switch tube and the preset temperature standard value. Specifically, the acquired temperature of the first switch tube S1 and the temperature of the second switch tube S2 are compared with the preset temperature standard value respectively. If the temperature difference between the temperature of the switch tube and the preset temperature standard value is too large, the temperature of the switch tube is determined to be abnormal, and the switching frequency of the switch tube with abnormal temperature is further adjusted according to the difference between the temperature of the switch tube with abnormal temperature and the preset temperature standard value, so that the temperatures of multiple parallel switch tubes fluctuate around the preset temperature standard value, ensuring the temperature balance of multiple switch tubes. For example, when the temperature of the switch tube with abnormal temperature is less than the preset temperature standard value, the switching frequency of the switch tube with abnormal temperature is increased to increase the heat generated by the switch tube with abnormal temperature during operation, thereby achieving temperature rise.

[0065] Therefore, the control method determines whether the temperature of the switch tube is abnormal according to the operating parameters of each switch tube, and achieves the temperature balance control effect by adjusting the switching frequency of the switch tube with abnormal temperature, thereby ensuring the reliable operation of the PFC circuit.

[0066] In one embodiment of the present invention, determining whether there is a switch tube with temperature abnormality among multiple switch tubes according to operating parameters includes: when the difference between the operating parameters of any switch tube among the multiple switch tubes and the operating parameters of at least one other switch tube is greater than a preset difference, and the change rate of the operating parameters of any switch tube is less than or equal to the preset change rate, determining that any switch tube has a primary temperature abnormality; wherein the other switch tubes are switch tubes other than any switch tube among the multiple switch tubes; when the difference between the operating parameters of any switch tube and the operating parameters of at least one other switch tube is greater than a preset difference, and the change rate of the operating parameters of any switch tube is greater than the preset change rate, determining that any switch tube has a secondary temperature abnormality.

[0067] Among them, the preset difference and the preset change rate can be set according to actual conditions. The preset difference is used to determine whether the temperature difference between the switch tubes is too large. For example, when the temperature difference between the two switch tubes exceeds the preset difference, it is considered that the temperature difference between the two switch tubes is too large and temperature balancing is required; if the temperature difference between the two switch tubes does not have a preset difference, it is considered that the temperature difference between the two switch tubes is small, which meets the temperature balancing requirements of the switch tubes of the PFC circuit. The preset change rate is used to determine the temperature change rate of the switch tube, wherein the positive and negative values ​​of the preset change rate can be used to indicate the direction of temperature change, for example, when the preset change rate is positive, it is used to determine the temperature rise rate of the switch tube, and when the preset change rate is negative, it is used to determine the temperature drop rate of the switch tube. For example, when the preset change rate is positive, if the change rate of the operating parameters of the switch tube exceeds the preset change rate, it is considered that the temperature rise slope of the switch tube is large and the temperature rise rate is fast; if the change rate of the operating parameters of the switch tube does not exceed the preset change rate, it is considered that the temperature rise slope of the switch tube is small and the temperature rise rate of the switch tube is slow.

[0068] Specifically, continue to take the case where the multiple parallel switch tubes are the first switch tube S1 and the second switch tube S2, and the operating parameter is temperature as an example, assuming that the temperature of the first switch tube S1 is higher than the temperature of the second switch tube S2, when the temperature difference between the first switch tube S1 and the second switch tube S2 exceeds the preset difference, and the temperature change rate of the first switch tube S1 is less than or equal to the preset change rate, it is considered that the temperature of the first switch tube S1 is too high and the temperature rise slope is not large, and it is determined that the first switch tube S1 has a primary temperature anomaly. When the temperature difference between the first switch tube S1 and the second switch tube S2 exceeds the preset difference, and the temperature change rate of the first switch tube S1 is greater than the preset change rate, it is considered that the temperature of the first switch tube S1 is too high and the temperature rise slope is large, and it is determined that the first switch tube S1 has a secondary temperature anomaly.

[0069] This embodiment divides the temperature anomalies, and the abnormality level of the secondary temperature anomaly is higher than the urgency of the primary temperature anomaly. Therefore, different temperature balance control strategies can be adopted based on the different types of temperature anomalies existing in the switch tube to improve the temperature control effect.

[0070] In one embodiment of the present invention, the temperature abnormality includes primary temperature abnormality and secondary temperature abnormality, and the switching frequency of the switch tube with the temperature abnormality is adjusted to balance the temperature of multiple switch tubes, including: when the switch tube with the temperature abnormality is in the primary temperature abnormality, the switching frequency of the switch tube with the temperature abnormality is reduced and the switching frequency after the reduction is greater than zero; when the switch tube with the temperature abnormality is in the secondary temperature abnormality, the switching frequency of the switch tube with the temperature abnormality is reduced and the switching frequency after the reduction is zero.

[0071] The first-level temperature anomaly and the second-level temperature anomaly can be distinguished by setting different judgment conditions, which are not limited here. Among them, the abnormality level of the second-level temperature anomaly is higher than the abnormality level of the first-level temperature anomaly.

[0072] Continue with Figure 2 Taking the case where the temperature of the first switch tube S1 is higher than the temperature of the second switch tube S2 as an example, when the temperature difference between the first switch tube S1 and the second switch tube S2 exceeds the preset difference, and the temperature rise rate of the first switch tube S1 is less than or equal to the preset change rate, it is determined that the first switch tube S1 is in the first level of temperature abnormality, and the switching frequency of the first switch tube S1 is reduced to keep the first switch tube S1 working at a lower switching frequency, thereby improving the service life of the switch tube and the product reliability to reduce the heat generated by the first switch tube S1 during operation, thereby achieving temperature balance control.

[0073] When the temperature difference between the first switch tube S1 and the second switch tube S2 exceeds the preset difference, and the temperature rise rate of the first switch tube S1 is greater than the preset change rate, it is determined that the first switch tube S1 is in the secondary temperature abnormality, and the switching frequency of the first switch tube S1 is reduced to zero, that is, the switching action of the first switch tube S1 is stopped. At this time, the stopped first switch tube S1 will no longer continue to generate heat, and the cooling of the first switch tube S1 is accelerated, so as to achieve temperature balance control, that is, the switch tube with a large temperature rise rate is subjected to wave-by-wave current limiting control, so as to reduce heat and achieve the effect of temperature balance control, and at the same time, it also prevents the first switch tube S1 from continuing to work and being damaged by overheating.

[0074] In one embodiment of the present invention, reducing the switching frequency of a switch tube with abnormal temperature includes: sealing a control signal of the switch tube with abnormal temperature at a preset time interval, wherein the preset time interval is an integer multiple of the switching period of the switch tube with abnormal temperature.

[0075] The wave blocking process is to block the drive of the switch tube, that is, to stop the output of the drive signal corresponding to the switch tube. At this time, the control end of the switch tube will not receive the drive voltage, so that the switch tube is in the off state.

[0076] This embodiment uses the integer multiple of the switching cycle of the switch tube with abnormal temperature as the preset time interval for wave sealing processing, which reduces the difficulty of implementation. For example, Figure 4 S1 in Figure 2 The first PWM driving signal corresponding to the first switch tube S1 in the embodiment of the present invention is as follows: when the first switch tube S1 is subjected to the wave-sealing process, the preset time interval is twice the switching cycle of the first switch tube S1, and the waveform of S1 after the wave-sealing process is as follows: Figure 5 shown.

[0077] In one embodiment of the present invention, when adjusting the switching frequency of a switch tube with abnormal temperature to balance the temperature of multiple switch tubes, the control method of the PFC circuit also includes: obtaining the working modes of the multiple switch tubes; and adjusting the switching frequency of the switch tube with normal temperature according to the working mode to keep the switching frequency of the PFC circuit unchanged.

[0078] The working modes of multiple switch tubes include synchronous on-off mode and alternating on-off mode. Figures 2 to 9 A control method for adjusting the switching frequency of a switch tube with normal temperature according to the working mode is described in detail. Wherein, PWM_S1 is a first PWM driving signal for driving the first switch tube S1, PWM_S2 is a first PWM driving signal for driving the second switch tube S2, PWM_S is the switching frequency of the PFC circuit, and Vds is the voltage between the drain d and the source s of the switch tube.

[0079] In the synchronous on-off mode, the conduction of the first switch tube S1 and the second switch tube S2 in the normal state is as follows: Figure 4 As shown, that is, the switching frequency of the PFC circuit is consistent with the switching frequency of the first switch tube S1 and the second switch tube S2. At this time, when one of the switch tubes is not turned on in a certain switching cycle, it will not affect the switching frequency of the PFC circuit.

[0080] In the alternating on-off mode, the conduction of the first switch tube S1 and the second switch tube S2 in the normal state is as follows: Figure 7 As shown, the first switch tube S1 and the second switch tube S2 are alternately turned on and off, and the switching frequency of the PFC circuit is the sum of the switching frequencies of the first switch tube S1 and the second switch tube S2. At this time, when one of the switch tubes is not turned on in a certain switching cycle, it will affect the switching frequency of the PFC circuit. Therefore, it is necessary to control the conduction of the other switch tube to fill the switching cycle of the wave sealing process to ensure that the switching frequency of the PFC circuit remains unchanged, further ensuring the stability of the output voltage of the PFC circuit and ensuring the working stability of the PFC circuit.

[0081] In one embodiment of the present invention, the switching frequency of the switch tube with normal temperature is adjusted according to the working mode, including: when the working mode is the synchronous on-off mode, the switching frequency of the switch tube with normal temperature is kept unchanged; when the working mode is the alternating on-off mode, at least one switch tube with normal temperature is controlled to be turned on when the control signal of the switch tube with abnormal temperature is sealed.

[0082] Specifically, when the first switch tube S1 and the second switch tube S2 are in the synchronous on-off mode, when the temperatures of the first switch tube S1 and the second switch tube S2 are both normal, such as Figure 4When it is determined that the first switch tube S1 has a first-level temperature abnormality and the temperature of the second switch tube S2 is normal, the first switch tube S1 is subjected to wave sealing processing according to a double switching cycle, such as Figure 5 As shown, that is, the wave blocking process is performed in the switching cycle of t1-t3, the switching cycle of t3-t4 maintains normal control, the wave blocking process is performed in the switching cycle of t4-t5, and so on, and the switching frequency of the second switch tube S2 remains unchanged. When it is determined that the first switch tube S1 has a secondary temperature abnormality and the temperature of the second switch tube S2 is normal, the first switch tube S1 is controlled to stop switching, such as Figure 6 As shown, the switching frequency of the first switch tube S2 remains unchanged.

[0083] When the first switch tube S1 and the second switch tube S2 are in the alternating on-off mode, when the temperatures of the first switch tube S1 and the second switch tube S2 are both normal, such as Figure 7 When it is determined that the first switch tube S1 has a first-level temperature abnormality and the temperature of the second switch tube S2 is normal, the first switch tube S1 is subjected to wave sealing processing according to a double switching cycle, such as Figure 8 As shown, t1-t5 is a switching cycle of the first switch tube S1, that is, the wave sealing process is performed in the switching cycle of t1-t5, and the switching cycle of t5-t9 maintains normal control, and so on. At the same time, the second switch tube S2 is controlled to be turned on in the switching cycle of the wave sealing process to fill the original turn-on time of the first switch tube S1 to ensure that the switching frequency of the PFC circuit remains unchanged. Taking the t1-t5 cycle of the wave sealing process as an example, the second switch tube S2 is controlled to be turned on within the original turn-on time t1-t2 of the first switch tube S1. When it is determined that the first switch tube S1 has a secondary temperature anomaly and the temperature of the second switch tube S2 is normal, the first switch tube S1 is controlled to stop the switching action, and the second switch tube S2 is turned on to fill the position of the first switch tube S1, as shown in the figure. Fig. 9 shown.

[0084] Therefore, this embodiment reduces the switching loss of a single switch tube by controlling the conduction timing of the parallel switch tubes. The control method is simple, effectively reduces the switching loss of the switch tube, reduces heat, realizes temperature balance control in the multi-tube parallel mode, and improves the operation reliability of the circuit.

[0085] Furthermore, after the switching frequency of the switch tube with abnormal temperature is reduced, the temperature of the switch tube with abnormal temperature is continuously monitored until its temperature drops to the allowable threshold and then the original switching frequency is restored to continue operation, thereby achieving temperature balance control. The allowable threshold may be a temperature allowable threshold or a temperature difference allowable threshold, which is not limited here.

[0086] Continuing to take the example of multiple parallel switch tubes including a first switch tube and a second switch tube, wherein the first switch tube has a temperature anomaly and performs frequency reduction control, when the allowable threshold is the temperature allowable threshold, the temperature of the first switch tube is compared with the temperature allowable threshold, and if it is determined that the temperature of the first switch tube drops to the temperature allowable threshold, it is considered that temperature balancing is completed, and the first switch tube is controlled to be restored to the original switching frequency, and the second switch tube can be restored to the original switching frequency based on the control strategy. When the allowable threshold is the temperature difference allowable threshold, the temperature difference between the first switch tube and the second switch tube is compared with the temperature difference allowable threshold, and if it is determined that the temperature difference between the first switch tube and the second switch tube drops to the temperature difference allowable threshold, it is considered that the purpose of temperature balancing is achieved, and the first switch tube is controlled to be restored to the original switching frequency, and the second switch tube can be restored to the original switching frequency based on the control strategy.

[0087] In one embodiment of the present invention, when adjusting the switching frequency of a switch tube with abnormal temperature to balance the temperature of multiple switch tubes, the control method of the PFC circuit further includes: when the operating parameter of any switch tube among the multiple switch tubes is greater than a preset protection parameter, controlling any switch tube to stop working to protect any switch tube from over-temperature, and controlling the switch tube without over-temperature protection to continue working. The operating parameter includes the temperature of the switch tube or the current flowing through the switch tube.

[0088] Next, the operating parameter is temperature, the preset protection parameter is the preset protection temperature threshold, and the PFC circuit used in the control method is: Figure 2 Taking the circuit shown as an example, the over-temperature protection control method is explained in detail.

[0089] Specifically, after obtaining the temperatures of the first switch tube S1 and the second switch tube S2, the temperatures of the first switch tube S1 and the second switch tube S2 are respectively compared with the preset protection temperature thresholds. Assuming that the temperature of the first switch tube S1 is greater than the preset protection temperature threshold and the temperature of the second switch tube S2 is less than the preset protection temperature threshold, it is considered that the temperature of the first switch tube S1 is too high and there is a risk of overheating and damage, and the first switch tube S1 is controlled to stop working to protect the first switch tube S1 from over-temperature. If it is considered that the temperature of the second switch tube S2 is normal and does not need over-temperature protection, the second switch tube S2 is controlled to continue working.

[0090] In addition, after determining that a switch tube in the PFC circuit needs over-temperature protection and controlling the switch tube that needs over-temperature protection to be disconnected, the switch tube that does not need over-temperature protection can continue to be driven according to the original drive signal, or the parameters of the drive signal can be adjusted according to actual working requirements. For example, by controlling the conduction of the switch tube that does not need over-temperature protection, the switching frequency of the PFC circuit can be ensured to remain unchanged.

[0091] It should be noted that the preset temperature protection threshold is determined based on the characteristics of the switch tube itself, which is the upper limit of the allowable operating temperature of the switch tube. In addition, the preset temperature protection threshold can also be determined in combination with the circuit characteristics of the PFC circuit to avoid the adverse effects of excessively high temperature of the switch tube on the normal operation of the PFC circuit. The specific setting can be made according to actual conditions.

[0092] Furthermore, the preset protection temperature threshold can be the minimum value of the upper limit of the allowable operating temperature of all the switch tubes in the PFC circuit, and the obtained switch tube temperature is compared with the preset protection threshold to determine whether the switch tube needs over-temperature protection. The preset protection temperature threshold can also be set in a one-to-one correspondence with the switch tube, and the obtained switch tube temperature is compared with the corresponding preset protection temperature threshold to determine whether the switch tube needs over-temperature protection, which is conducive to the normal use of the switch tube and the optimal working performance.

[0093] In one embodiment of the present invention, after controlling any switch tube to stop working to perform over-temperature protection on any switch tube, the control method of the PFC circuit also includes: if the operating parameter of any switch tube is less than a preset recovery parameter, controlling any switch tube to work again, wherein the preset recovery parameter is less than the preset protection parameter.

[0094] Next, taking the operating parameter as temperature and the preset protection parameter as the preset protection temperature threshold as an example, the preset recovery parameter is the preset recovery temperature threshold, wherein the preset recovery temperature threshold is less than the preset protection temperature threshold.

[0095] After confirming that the first switch tube S1 needs over-temperature protection and controlling the first switch tube S1 to stop working, the temperature of the first switch tube S1 is continuously monitored, and the acquired temperature of the first switch tube S1 is compared with the preset recovery temperature threshold. When it is determined that the temperature of the first switch tube S1 is less than or equal to the preset recovery temperature threshold, the first switch tube S1 is controlled to work again at the preset frequency, and the specific operating parameters can be set according to the actual situation. If it is determined that the temperature of the first switch tube S1 is still greater than the preset recovery temperature threshold, the first switch tube S1 is continuously controlled to stop working until the temperature of the first switch tube S1 drops to the preset recovery temperature threshold. Among them, the preset recovery temperature threshold can be set according to the parameters of the switch tube, and can also be set based on the preset protection temperature threshold.

[0096] In addition, after the first switch tube S1 is controlled to stop working, only the second switch tube S2 continues to work to maintain the output of the PFC circuit. During this process, the temperature of the first switch tube S1 gradually decreases, and the temperature of the second switch tube S2 rises more rapidly. Therefore, it is also necessary to judge the temperature of the second switch tube S2 that continues to work.

[0097] In one embodiment of the present invention, the control method of the PFC circuit also includes: in the process of controlling any switch tube to resume working, or before the operating parameter of any switch tube is less than the preset recovery parameter, if the operating parameter of the switch tube without over-temperature protection is greater than the preset protection parameter, then the switch tube without over-temperature protection is controlled to stop working.

[0098] Specifically, continue with Figure 2 For example, the first switch tube S1 performs temperature protection, the second switch tube S2 continues to work, the operating parameter is temperature, the preset protection parameter is the preset protection temperature threshold, and the preset recovery parameter is the preset recovery temperature threshold.

[0099] When the temperature of the first switch tube S1 drops to the preset recovery temperature threshold, if the temperature of the second switch tube S2 is still lower than the preset protection temperature threshold, the first switch tube S1 and the second switch tube S2 are controlled to work according to the preset working mode. For example, an alternating on-off mode can be adopted, and the alternating on-off operation of multiple switch tubes can improve the current resistance of the switch tube, ensure the service life of the switch tube, and easily improve the working performance of the PFC circuit.

[0100] When the temperature of the first switch tube S1 drops to a preset recovery temperature threshold, if the temperature of the second switch tube S2 that is continuously working reaches a preset protection temperature threshold, the second switch tube S2 is controlled to stop working to perform over-temperature protection on the second switch tube S2, and the first switch tube S1 is controlled to resume working at a preset frequency to ensure the normal operation of the PFC circuit.

[0101] Before the temperature of the first switch tube S1 that has stopped working drops to the preset recovery temperature threshold, if it is determined that the temperature of the second switch tube S2 that continues to work has reached the preset protection temperature threshold and over-temperature protection is required, the second switch tube S2 is controlled to stop working and the PFC circuit stops running until the temperature of at least one switch tube drops to the preset recovery temperature threshold, and then the PFC circuit is restarted.

[0102] The control method enables each switch tube in the PFC circuit to be fully utilized, and the application of the PFC circuit is not affected by the temperature of a single switch tube, thereby improving the working performance of the PFC circuit.

[0103] As a specific embodiment of the present application, a PFC circuit is used as Figure 2 Taking the circuit diagram shown as an example, the operating parameter is temperature, the preset protection parameter is a preset protection temperature threshold, and the preset recovery parameter is a preset recovery temperature threshold. The control method of the PFC circuit includes temperature balance control and over-temperature protection control.

[0104] The control method of the PFC circuit based on temperature balance control is as follows Fig.10 As shown, the following steps may be included:

[0105] S301, controlling the first switch tube and the second switch tube to operate according to a preset frequency.

[0106] S302, obtaining the temperature t1 of the first switch tube and the temperature t2 of the second switch tube.

[0107] S303, determine whether the temperature t1 of the first switch tube is greater than the temperature t2 of the second switch tube. If yes, execute step S304; if not, execute step S312.

[0108] S304, determining whether the temperature difference between the first switch tube and the second switch tube is greater than a preset difference a. If yes, executing step S305; if not, executing step S302.

[0109] S305, determining whether the temperature change rate k1 of the first switch tube is less than or equal to a preset change rate K. If so, executing step S306; if not, executing step S308.

[0110] S306, determining that the first switch tube is in a level one temperature abnormality and the temperature of the second switch tube is normal.

[0111] S307, reducing the switching frequency of the switch tube with abnormal temperature and making the reduced switching frequency greater than zero, and adjusting the switching frequency of the switch tube with normal temperature according to the working mode of the switch tube, so that the switching frequency of the PFC circuit remains unchanged. Execute step S310.

[0112] S308, determining that the first switch tube is in a level 2 temperature abnormality and the temperature of the second switch tube is normal.

[0113] S309, reducing the switching frequency of the switch tube with abnormal temperature to zero, and adjusting the switching frequency of the switch tube with normal temperature according to the working mode of the switch tube, so that the switching frequency of the PFC circuit remains unchanged. Execute step S310.

[0114] S310, obtaining the temperature t3 of the switch tube with abnormal temperature.

[0115] S311, determine whether the temperature t3 of the switch tube with abnormal temperature is less than or equal to the preset temperature allowable threshold b. If yes, execute step S301; if not, execute step S310.

[0116] S312, determining whether the temperature difference between the second switch tube and the first switch tube is greater than a preset difference a. If yes, executing step S313; if not, executing step S302.

[0117] S313, determining whether the temperature change rate k2 of the second switch tube is less than or equal to a preset change rate K. If so, executing step S314; if not, executing step S315.

[0118] S314, determining that the second switch tube is in a level 1 temperature abnormality and the temperature of the first switch tube is normal. Execute step S307.

[0119] S315, determining that the second switch tube is in the second-level temperature abnormality and the temperature of the first switch tube is normal. Execute step S309.

[0120] The control method of the PFC circuit based on over-temperature protection control is as follows Fig.11 As shown, the following steps are included:

[0121] S401, controlling the first switch tube and the second switch tube to operate.

[0122] S402, respectively obtaining the temperature t1 of the first switch tube and the temperature t2 of the second switch tube.

[0123] S403, determining whether the temperature t1 of the first switch tube and the temperature t2 of the second switch tube are both greater than or equal to a preset protection temperature threshold T1. If so, executing step S404; if not, executing step S408.

[0124] S404, controlling the first switch tube and the second switch tube to stop working.

[0125] S405, obtaining the temperature t1 of the first switch tube and the temperature t2 of the second switch tube when the operation is stopped, and determining whether the temperature t1 of the first switch tube and the temperature t2 of the second switch tube are both less than or equal to the preset recovery temperature threshold T2. If so, execute step S401; if not, execute step S406.

[0126] S406, determining whether one of the temperature t1 of the first switch tube and the temperature t2 of the second switch tube is less than or equal to a preset recovery temperature threshold T2. If so, executing step S407; if not, executing step S404.

[0127] S407, control the switch tubes whose temperature drops to the preset recovery threshold value T2 to resume operation, and control the switch tubes whose temperature does not drop to the preset recovery threshold value T2 to stop operation. Execute step S410.

[0128] S408, determining whether the temperature t1 of the first switch tube and the temperature t2 of the second switch tube are both lower than the preset protection temperature threshold T1. If so, executing step S401; if not, executing step S409.

[0129] S409, controlling the switch tube whose temperature is greater than or equal to the preset protection temperature threshold T1 to stop working, and controlling the other switch tube to continue working.

[0130] S410, determining whether the temperature of the switch tube that continues to work is greater than or equal to a preset protection temperature threshold T1. If so, executing step S411; if not, executing step S413.

[0131] S411, determine whether the temperature of the stopped switch tube is less than or equal to a preset recovery temperature threshold T2. If so, execute step S412; if not, execute step S404.

[0132] S412, control the switch tube that stopped working to resume working, and control the switch tube that continued to work to stop working. Execute step S410.

[0133] S413, determining whether the temperature of the stopped switch tube is less than or equal to a preset recovery temperature threshold T2. If so, executing step S401; if not, executing step S414.

[0134] S414, control the switch tube that continues to work to continue working, and control the switch tube that stops working to stop working. Execute step S410.

[0135] In summary, the PFC circuit according to the embodiment of the present invention includes a plurality of switch tubes in a parallel state. The control method of the PFC circuit first obtains the operating parameters of each of the plurality of switch tubes, and determines whether there is a switch tube with abnormal temperature among the plurality of switch tubes according to the operating parameters. When there is a switch tube with abnormal temperature among the plurality of switch tubes, the switching frequency of the switch tube with abnormal temperature is adjusted to balance the temperature of the plurality of switch tubes. Thus, the method determines the switch tube with abnormal temperature according to the operating parameters of each switch tube, and adjusts the switching frequency of the switch tube with abnormal temperature, thereby achieving temperature regulation of the switch tube, so as to achieve the effect of temperature balancing of the parallel switch tubes, and improve the service life of the switch tube and the operating reliability of the PFC circuit.

[0136] Corresponding to the above embodiment, the present invention also proposes a computer-readable storage medium.

[0137] The computer-readable storage medium of the embodiment of the present invention stores a control program of a PFC circuit, and the control program of the PFC circuit implements the above-mentioned control method of the PFC circuit when executed by a processor.

[0138] According to the computer-readable storage medium of an embodiment of the present invention, the control method of the PFC circuit described above is implemented when the control program of the PFC circuit is executed by the processor. Based on the control method of the PFC circuit described above, the switch tube with abnormal temperature is determined according to the operating parameters of each switch tube, and the switching frequency of the switch tube with abnormal temperature is adjusted, thereby realizing temperature regulation of the switch tube, so as to achieve the effect of temperature balancing of the parallel switch tubes, and improve the service life of the switch tube and the operating reliability of the PFC circuit.

[0139] Corresponding to the above embodiment, the present invention further proposes a PFC circuit.

[0140] like Fig.12 As shown, the PFC circuit of the embodiment of the present invention includes: a plurality of switch tubes 11 in parallel, an acquisition unit 12, a determination unit 13 and a control unit 14.

[0141] The acquisition unit 12 is used to acquire the operating parameters of each switch tube 11 in the multiple switch tubes 11. The determination unit 13 is used to determine whether there is a switch tube with abnormal temperature in the multiple switch tubes 11 according to the operating parameters. The control unit 14 is used to adjust the switching frequency of the switch tube with abnormal temperature when there is a switch tube with abnormal temperature in the multiple switch tubes 11, so as to balance the temperature of the multiple switch tubes 11.

[0142] According to one embodiment of the present invention, the determination unit 13 determines whether there is a switch tube with temperature abnormality among the multiple switch tubes 11 based on the operating parameters, and is specifically used to: when the difference between the operating parameters of any switch tube among the multiple switch tubes 11 and the operating parameters of at least one other switch tube is greater than a preset difference, and the change rate of the operating parameters of any switch tube is less than or equal to the preset change rate, determine that any switch tube has a first-level temperature abnormality; wherein the other switch tubes are switch tubes other than any switch tube among the multiple switch tubes; when the difference between the operating parameters of any switch tube and the operating parameters of at least one other switch tube is greater than the preset difference, and the change rate of the operating parameters of any switch tube is greater than the preset change rate, determine that any switch tube has a second-level temperature abnormality.

[0143] According to one embodiment of the present invention, the temperature abnormality includes a primary temperature abnormality and a secondary temperature abnormality. The control unit 14 adjusts the switching frequency of the switch tube with the temperature abnormality to balance the temperature of multiple switch tubes, specifically for: when the switch tube with the temperature abnormality is in the primary temperature abnormality, the switching frequency of the switch tube with the temperature abnormality is reduced and the switching frequency after the reduction is greater than zero; when the switch tube with the temperature abnormality is in the secondary temperature abnormality, the switching frequency of the switch tube with the temperature abnormality is reduced and the switching frequency after the reduction is zero.

[0144] According to one embodiment of the present invention, the control unit 14 reduces the switching frequency of the switch tube with abnormal temperature, and is specifically used to: perform wave sealing processing on the control signal of the switch tube with abnormal temperature according to a preset time interval, wherein the preset time interval is an integer multiple of the switching period of the switch tube with abnormal temperature.

[0145] According to one embodiment of the present invention, when adjusting the switching frequency of a switch tube with abnormal temperature to balance the temperature of multiple switch tubes, the acquisition unit 12 is also used to: obtain the working modes of the multiple switch tubes; the control unit 14 is also used to adjust the switching frequency of the switch tube with normal temperature according to the working mode to keep the switching frequency of the PFC circuit unchanged.

[0146] According to one embodiment of the present invention, the control unit 14 adjusts the switching frequency of the switch tube with normal temperature according to the working mode, and is specifically used to: when the working mode is the synchronous on-off mode, keep the switching frequency of the switch tube with normal temperature unchanged; when the working mode is the alternating on-off mode, control at least one switch tube with normal temperature to be turned on when the control signal of the switch tube with abnormal temperature is sealed.

[0147] According to one embodiment of the present invention, when the switching frequency of a switch tube with abnormal temperature is adjusted to balance the temperature of multiple switch tubes, the control unit 14 is also used to: when the operating parameter of any switch tube among the multiple switch tubes is greater than a preset protection parameter, control any switch tube to stop working to perform over-temperature protection on any switch tube, and control the switch tube without over-temperature protection to continue working.

[0148] According to an embodiment of the present invention, the operating parameter includes the temperature of the switch tube or the current flowing through the switch tube.

[0149] According to one embodiment of the present invention, after controlling any switch tube to stop working to perform over-temperature protection on any switch tube, the control unit is also used to: if the operating parameter of any switch tube is less than a preset recovery parameter, control any switch tube to restart working, wherein the preset recovery parameter is less than the preset protection parameter.

[0150] According to one embodiment of the present invention, the control unit 14 is also used to: in the process of controlling any switch tube to resume working, or before the operating parameter of any switch tube is less than the preset recovery parameter, if the operating parameter of the switch tube without over-temperature protection is greater than the preset protection parameter, then the switch tube without over-temperature protection is controlled to stop working.

[0151] It should be noted that for details not disclosed in the PFC circuit of the embodiment of the present invention, please refer to the details disclosed in the control method of the PFC circuit of the above embodiment of the present invention, and the details will not be repeated here.

[0152] In summary, according to the PFC circuit of the embodiment of the present invention, the acquisition unit acquires the operating parameters of each of the multiple switch tubes, and the determination unit determines whether there is a switch tube with abnormal temperature among the multiple switch tubes according to the operating parameters. When there is a switch tube with abnormal temperature among the multiple switch tubes, the control unit adjusts the switching frequency of the switch tube with abnormal temperature to balance the temperature of the multiple switch tubes. Thus, the PFC circuit can determine the switch tube with abnormal temperature according to the operating parameters of each switch tube, and adjust the switching frequency of the switch tube with abnormal temperature, thereby realizing temperature regulation of the switch tube, so as to achieve the effect of temperature balancing of the parallel switch tubes, and improve the service life of the switch tube and the operating reliability of the PFC circuit.

[0153] Corresponding to the above embodiment, the present invention also proposes an electrical device.

[0154] like Fig.13 As shown, the electrical device 100 of the embodiment of the present invention includes the above-mentioned PFC circuit 10. The electrical device 100 uses a product in which multiple switches work in parallel, such as air conditioners, washing machines, refrigerators, UPS (Uninterruptible Power Supply), photovoltaic equipment, etc.

[0155] The electrical equipment according to the embodiment of the present invention improves the operating reliability of the electrical equipment based on the above-mentioned PFC circuit.

[0156] Corresponding to the above embodiment, the present invention also proposes an air conditioner.

[0157] like Fig.14 As shown, the air conditioner 200 of the embodiment of the present invention includes a memory 210, a processor 220, and a control program of the PFC circuit stored in the memory 210 and executable on the processor 220. When the processor 220 executes the control program of the PFC circuit, the above-mentioned control method of the PFC circuit is implemented.

[0158] In the air conditioner according to the embodiment of the present invention, when the processor executes the control program of the PFC circuit, the control method of the PFC circuit is implemented. Based on the control method of the PFC circuit, the switch tube with abnormal temperature can be determined according to the operating parameters of each switch tube, and the switching frequency of the switch tube with abnormal temperature can be adjusted, thereby realizing temperature regulation of the switch tube, so as to achieve the effect of temperature balancing of the parallel switch tubes, and improve the service life of the switch tube and the operating reliability of the PFC circuit.

[0159] It should be noted that the logic and / or steps represented in the flowchart or otherwise described herein, for example, can be considered as a sequenced list of executable instructions for implementing logical functions, and can be specifically implemented in any computer-readable medium for use by an instruction execution system, device or apparatus (such as a computer-based system, a system including a processor, or other system that can fetch instructions from an instruction execution system, device or apparatus and execute instructions), or in combination with these instruction execution systems, devices or apparatuses. For the purposes of this specification, "computer-readable medium" can be any device that can contain, store, communicate, propagate or transmit a program for use by an instruction execution system, device or apparatus, or in combination with these instruction execution systems, devices or apparatuses. More specific examples of computer-readable media (a non-exhaustive list) include the following: an electrical connection portion with one or more wirings (electronic device), a portable computer disk box (magnetic device), a random access memory (RAM), a read-only memory (ROM), an erasable and programmable read-only memory (EPROM or flash memory), an optical fiber device, and a portable compact disk read-only memory (CDROM). In addition, the computer-readable medium may even be paper or other suitable medium on which the program is printed, since the program may be obtained electronically, for example, by optically scanning the paper or other medium and then editing, interpreting or processing in other suitable ways if necessary, and then stored in a computer memory.

[0160] It should be understood that the various parts of the present invention can be implemented by hardware, software, firmware or a combination thereof. In the above-mentioned embodiments, a plurality of steps or methods can be implemented by software or firmware stored in a memory and executed by a suitable instruction execution system. For example, if implemented by hardware, as in another embodiment, it can be implemented by any one of the following technologies known in the art or their combination: a discrete logic circuit having a logic gate circuit for implementing a logic function for a data signal, a dedicated integrated circuit having a suitable combination of logic gate circuits, a programmable gate array (PGA), a field programmable gate array (FPGA), etc.

[0161] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "examples", "specific examples", or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner.

[0162] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In the description of the present invention, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0163] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0164] Although the embodiments of the present invention have been shown and described above, it is to be understood that the above embodiments are exemplary and are not to be construed as limitations of the present invention. A person skilled in the art may change, modify, replace and vary the above embodiments within the scope of the present invention.

Claims

1. A control method for a PFC circuit, characterized in that: The PFC circuit includes a plurality of switch tubes in parallel, and the method includes: Acquire an operating parameter of each of the plurality of switch tubes; Determine whether there is a switch tube with abnormal temperature among the plurality of switch tubes according to the operating parameters; When a switch tube with abnormal temperature exists among the plurality of switch tubes, the switching frequency of the switch tube with abnormal temperature is adjusted to balance the temperatures of the plurality of switch tubes.

2. The method according to claim 1, characterized in that The determining, according to the operating parameters, whether there is a switch tube with abnormal temperature among the plurality of switch tubes includes: When the difference between the operating parameter of any switch tube among the plurality of switch tubes and the operating parameter of at least one other switch tube is greater than a preset difference, and the change rate of the operating parameter of the arbitrary switch tube is less than or equal to the preset change rate, it is determined that the arbitrary switch tube has a first-level temperature anomaly; wherein the other switch tube is a switch tube among the plurality of switch tubes except the arbitrary switch tube; When the difference between the operating parameter of the arbitrary switching tube and the operating parameter of at least one of the other switching tubes is greater than the preset difference, and the change rate of the operating parameter of the arbitrary switching tube is greater than the preset change rate, it is determined that the arbitrary switching tube has a secondary temperature anomaly.

3. The method according to claim 1, characterized in that The temperature anomaly includes primary temperature anomaly and secondary temperature anomaly, and the switching frequency of the switch tube with temperature anomaly is adjusted to balance the temperature of the plurality of switch tubes, including: When the switch tube with temperature abnormality is in the first level of temperature abnormality, reducing the switching frequency of the switch tube with temperature abnormality and the switching frequency after reduction is greater than zero; When the switch tube with temperature abnormality is in the second-level temperature abnormality, the switching frequency of the switch tube with temperature abnormality is reduced and the reduced switching frequency is zero.

4. The method according to any one of claims 1 to 3, characterized in that: Reducing the switching frequency of the switch tube with abnormal temperature includes: The control signal of the switch tube with abnormal temperature is subjected to wave sealing processing at a preset time interval, wherein the preset time interval is an integer multiple of the switching period of the switch tube with abnormal temperature.

5. The method according to claim 4, characterized in that When adjusting the switching frequency of the switch tube with abnormal temperature to balance the temperature of the plurality of switch tubes, the method further includes: Acquire the working modes of the plurality of switch tubes; According to the working mode, the switching frequency of the switch tube with normal temperature is adjusted to keep the switching frequency of the PFC circuit unchanged.

6. The method according to claim 5, characterized in that The step of adjusting the switching frequency of the switch tube with normal temperature according to the working mode includes: When the working mode is the synchronous on-off mode, the switching frequency of the switch tube with normal temperature is kept unchanged; When the working mode is the alternating on-off mode, at least one of the switch tubes with normal temperature is controlled to be turned on when the control signal of the switch tube with abnormal temperature is sealed.

7. The method according to claim 1, characterized in that When adjusting the switching frequency of the switch tube with abnormal temperature to balance the temperature of the plurality of switch tubes, the method further includes: When the operating parameter of any switch tube among the multiple switch tubes is greater than the preset protection parameter, the arbitrary switch tube is controlled to stop working to perform over-temperature protection on the arbitrary switch tube, and the switch tube without over-temperature protection is controlled to continue working.

8. The method according to claim 7, characterized in that The operating parameters include the temperature of the switch tube or the current flowing through the switch tube.

9. The method according to claim 7, characterized in that: After controlling the arbitrary switch tube to stop working so as to perform over-temperature protection on the arbitrary switch tube, the method further includes: If the operating parameter of any switch tube is less than a preset recovery parameter, the any switch tube is controlled to work again, wherein the preset recovery parameter is less than the preset protection parameter.

10. The method according to claim 9, characterized in that The method further comprises: In the process of controlling any of the switch tubes to resume working, or before the operating parameters of any of the switch tubes are less than the preset recovery parameters, if the operating parameters of the switch tube without over-temperature protection are greater than the preset protection parameters, the switch tube without over-temperature protection is controlled to stop working.

11. A computer-readable storage medium, characterized in that: A control program of a PFC circuit is stored thereon, and when the control program of the PFC circuit is executed by a processor, a control method of a PFC circuit according to any one of claims 1 to 10 is implemented.

12. A PFC circuit, characterized in that: include: Multiple switching tubes in parallel; An acquisition unit, used for acquiring an operating parameter of each of the plurality of switch tubes; a determination unit, configured to determine whether there is a switch tube with abnormal temperature among the plurality of switch tubes according to the operating parameters; The control unit is used to adjust the switching frequency of the switch tube with abnormal temperature when there is a switch tube with abnormal temperature among the multiple switch tubes, so as to balance the temperature of the multiple switch tubes.

13. An electrical device, characterized in that: Comprising the PFC circuit according to claim 12.

14. An air conditioner, characterized in that: The invention comprises a memory, a processor and a control program of a PFC circuit which is stored in the memory and can be run on the processor. When the processor executes the control program of the PFC circuit, the control method of the PFC circuit according to any one of claims 1 to 10 is implemented.

Images