Conversion circuit, refrigeration device, and control method for PFC circuit in refrigeration device

Abstract

Provided are a conversion circuit (300), a refrigeration device (100), and a control method for a PFC circuit (110) in the refrigeration device. The conversion circuit (300) comprises: a bridge circuit (310), wherein the bridge circuit (310) comprises a plurality of switch transistors, the plurality of switch transistors are connected to form a bridge configuration, and the bridge circuit is provided with an input end and an output end; an inductor (L1); a capacitor (C1), wherein the capacitor (C1) is connected to the output end and is adapted to perform voltage stabilization processing on an output voltage of the bridge circuit (310) so as to provide a direct-current power supply; and a controller (320), configured to acquire a torque of a motor (410) and control the plurality of switch transistors on the basis of the torque of the motor (410) so as to switch the working mode of the conversion circuit (300), wherein the working mode of the conversion circuit (300) comprises a synchronous rectification mode and a high-frequency PFC mode.

Description

Conversion circuit, refrigeration equipment and control method of PFC circuit thereof

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This disclosure claims priority to Chinese patent application number 202311124828.3, filed on August 31, 2023, entitled “Conversion circuit, refrigeration equipment and control method of its PFC circuit,” the entire contents of which are incorporated by reference into this disclosure. Technical Field

[0003] The present disclosure relates to the technical field of household appliances, and in particular to a conversion circuit, a refrigeration device, and a control method for a PFC circuit thereof. Background Art

[0004] With the development of power electronics technology, active PFC (Power Factor Correction) technology has gained widespread application due to its advantages such as high power factor, low harmonic current, and stable output voltage. Currently, the most commonly used type of PFC is boost-type PFC, which has a simple structure and is easy to control, but suffers from relatively low efficiency. Therefore, in applications where high efficiency is required, a bridgeless totem-pole PFC circuit is used. This circuit reduces the number of components in the circuit and improves efficiency.

[0005] In existing electrical devices, PFC circuits can simultaneously perform synchronous rectification and high-frequency PFC functions. Since high-frequency PFC mode results in significant circuit losses, the PFC circuit needs to switch between synchronous rectification and high-frequency PFC. In related technologies, switching between synchronous rectification and high-frequency PFC is typically done by determining the input current. However, the input current is typically sampled and calculated using analog-to-digital converters (ADCs), which often results in significant delays and deviations, making it difficult to effectively control power losses and resulting in low energy efficiency.

[0006] Public content

[0007] The present disclosure aims to address, at least to some extent, one of the technical problems in the related art. To this end, a first object of the present disclosure is to provide a conversion circuit that, when converting an input AC power source into a DC power source to power a motor load, can quickly and accurately switch between a synchronous rectification mode and a high-frequency PFC mode based on the actual torque of the motor, achieving enhanced real-time performance and accuracy, thereby achieving high efficiency and energy saving.

[0008] The second objective of the present disclosure is to provide an electrical device.

[0009] A third objective of the present disclosure is to provide a method for controlling a PFC circuit in a refrigeration device.

[0010] A fourth object of the present disclosure is to provide a computer-readable storage medium.

[0011] The fifth objective of the present disclosure is to provide a controller.

[0012] A sixth objective of the present disclosure is to provide a refrigeration device.

[0013] To achieve the above-mentioned purpose, the first aspect embodiment of the present disclosure proposes a conversion circuit, which is suitable for converting an input AC power supply into a DC power supply to power a motor. The conversion circuit includes: a bridge circuit, which includes a plurality of switching tubes, and the plurality of switching tubes are connected in a bridge shape and are constructed with an input end and an output end; an inductor, which is connected between the AC power supply and the input end; a capacitor, which is connected to the output end and is suitable for stabilizing the output voltage of the bridge circuit to provide the DC power supply; a controller, which is configured to obtain the torque of the motor and control the plurality of switching tubes according to the torque of the motor to switch the working mode of the conversion circuit, wherein the working mode of the conversion circuit includes a synchronous rectification mode and a high-frequency PFC mode.

[0014] According to the conversion circuit of the embodiment of the present disclosure, in the process of converting the input AC power supply into DC power supply to power the motor, the actual torque of the motor is obtained, and based on the torque of the motor, rapid and accurate switching between the synchronous rectification mode and the high-frequency PFC mode is achieved. It has high real-time performance and precise switching, avoids unnecessary power loss, and achieves the goals of high efficiency and energy saving while ensuring reliable and stable operation of the motor.

[0015] In addition, the conversion circuit according to the above embodiment of the present disclosure may also have the following additional technical features:

[0016] Optionally, in some embodiments, the multiple switching tubes are configured as a first bridge arm and a second bridge arm connected in parallel, the midpoint of the first bridge arm and the midpoint of the second bridge arm serve as the input end, the two ends of the first bridge arm or the second bridge arm serve as the output end, and the midpoint of the first bridge arm is connected to the AC power supply through the inductor.

[0017] Furthermore, the upper bridge switch tube and the lower bridge switch tube in the first bridge arm are configured as fast tubes, and the upper bridge switch tube and the lower bridge switch tube in the second bridge arm are configured as slow tubes.

[0018] Optionally, in some embodiments, the switching element in the fast tube is a silicon carbide MOSFET or a gallium nitride MOSFET.

[0019] Optionally, in some embodiments, when the conversion circuit operates in the synchronous rectification mode, the upper bridge switch tube and the lower bridge switch tube in the first bridge arm are turned on or off based on the polarity of the AC power supply, and the upper bridge switch tube and the lower bridge switch tube in the second bridge arm are turned on or off based on the magnitude and polarity of the current flowing through the inductor.

[0020] Optionally, in some embodiments, when the conversion circuit operates in the synchronous rectification mode, the upper bridge switch tube and the lower bridge switch tube in the second bridge arm are turned on or off based on the polarity of the AC power supply, and the upper bridge switch tube and the lower bridge switch tube in the first bridge arm are turned on or off based on the magnitude and polarity of the current flowing through the inductor.

[0021] Optionally, in some embodiments, when the conversion circuit operates in the high-frequency PFC mode, the upper bridge switch tube and the lower bridge switch tube in the second bridge arm are turned on or off based on the polarity of the AC power supply, and the upper bridge switch tube and the lower bridge switch tube in the first bridge arm are alternately turned on or off based on the set frequency.

[0022] Optionally, in some embodiments, when the conversion circuit operates in the synchronous rectification mode, if the upper bridge switch tube and the lower bridge switch tube in the first bridge arm are turned on or off based on the polarity of the AC power supply, the first bridge arm is used as a zero-voltage turned-on bridge arm; if the upper bridge switch tube and the lower bridge switch tube in the second bridge arm are turned on or off based on the polarity of the AC power supply, the second bridge arm is used as a zero-voltage turned-on bridge arm.

[0023] Optionally, in some embodiments, the controller is further configured to determine one of the first bridge arm and the second bridge arm as the zero voltage turn-on bridge arm according to the total working time of the first bridge arm and the total working time of the second bridge arm.

[0024] Optionally, in some embodiments, the controller is further configured to determine the zero-voltage turn-on bridge arm when operating in the synchronous rectification mode this time based on the zero-voltage turn-on bridge arm when the conversion circuit last operated in the synchronous rectification mode.

[0025] Optionally, in some embodiments, the controller is further configured to, when the torque is greater than or equal to a first preset value, control the conversion circuit to switch to the high-frequency PFC mode to operate; and when the torque is less than the first preset value, control the conversion circuit to switch to the synchronous rectification mode to operate.

[0026] Optionally, in some embodiments, the controller is further configured to obtain the speed of the motor, and determine the torque based on the speed difference between the speed of the motor and the target speed, and determine the product value between the speed of the motor and the torque, wherein, when the product value is greater than or equal to a second preset value, the conversion circuit is controlled to switch to the high-frequency PFC mode for operation; when the product value is less than the second preset value, the conversion circuit is controlled to switch to the synchronous rectification mode for operation.

[0027] The second embodiment of the present disclosure proposes an electrical device, which includes: a motor; and a conversion circuit described in the above embodiment, wherein the conversion circuit is suitable for converting an input AC power supply into a DC power supply to power the motor.

[0028] According to the electrical equipment of the embodiment of the present disclosure, based on the conversion circuit described in the above embodiment, in the process of converting the input AC power supply into DC power supply to power the motor, it is possible to quickly and accurately switch between the synchronous rectification mode and the high-frequency PFC mode based on the torque of the motor. It has high real-time performance and precise switching, avoids unnecessary power loss, and achieves the goals of high efficiency and energy saving while ensuring reliable and stable operation of the motor.

[0029] An embodiment of a second aspect of the present disclosure provides a method for controlling a PFC circuit in a refrigeration device, wherein the PFC circuit includes a synchronous rectification mode and a high-frequency PFC mode. The method includes: determining the torque of a compressor in the refrigeration device; and controlling the PFC circuit to switch between the synchronous rectification mode and the high-frequency PFC mode according to the torque of the compressor.

[0030] According to the control method of the PFC circuit in the refrigeration equipment of the embodiment of the present disclosure, the torque of the compressor in the refrigeration equipment is determined to control the PFC circuit to switch between the synchronous rectification mode and the high-frequency PFC mode. In this way, the switching point of the PFC circuit between the synchronous rectification mode and the high-frequency PFC mode is determined by the torque of the compressor. This method has higher real-time performance and accuracy, precise switching, and can avoid unnecessary power loss. While ensuring reliable and stable operation of the motor, it achieves the goals of high efficiency and energy saving.

[0031] In addition, the control method of the PFC circuit in the refrigeration equipment according to the above embodiment of the present disclosure may also have the following additional technical features:

[0032] According to one embodiment of the present disclosure, a PFC circuit is controlled to switch between a synchronous rectification mode and a high-frequency PFC mode according to the torque of the compressor, including: when the torque is greater than or equal to a first preset value, controlling the PFC circuit to switch to the high-frequency PFC mode to operate; when the torque is less than the first preset value, controlling the PFC circuit to switch to the synchronous rectification mode to operate.

[0033] According to one embodiment of the present disclosure, determining the torque of the compressor in the refrigeration equipment includes: acquiring the rotational speed of the compressor; and determining the torque of the compressor based on a rotational speed difference between the rotational speed of the compressor and a target rotational speed.

[0034] According to another embodiment of the present disclosure, a PFC circuit is controlled to switch between a synchronous rectification mode and a high-frequency PFC mode according to the torque of the compressor, including: determining a product value between the speed and torque of the compressor; when the product value is greater than or equal to a second preset value, controlling the PFC circuit to switch to the high-frequency PFC mode for operation; when the product value is less than the second preset value, controlling the PFC circuit to switch to the synchronous rectification mode for operation.

[0035] According to one embodiment of the present disclosure, the PFC circuit includes an inductor and a bridge circuit, the bridge circuit includes a plurality of switching tubes, the plurality of switching tubes being configured to form a first bridge arm and a second bridge arm connected in parallel, one of the first bridge arm and the second bridge arm being connected to the inductor, wherein the upper bridge switching tube and the lower bridge switching tube in the first bridge arm are turned on or off based on the polarity of the input AC power supply, and the upper bridge switching tube and the lower bridge switching tube in the second bridge arm are turned on or off based on the magnitude and polarity of the current flowing through the inductor, the PFC circuit operates in the synchronous rectification mode; or, in the first bridge arm, the upper bridge switching tube and the lower bridge switching tube are turned on or off based on the magnitude and polarity of the current flowing through the inductor. When the upper bridge switch tube and the lower bridge switch tube in the second bridge arm are turned on or off based on the polarity of the input AC power supply, and the upper bridge switch tube and the lower bridge switch tube in the first bridge arm are turned on or off based on the magnitude and polarity of the current flowing through the inductor, the PFC circuit operates in the synchronous rectification mode; when the upper bridge switch tube and the lower bridge switch tube in the bridge arm connected to the inductor are alternately turned on or off based on a set frequency, and the upper bridge switch tube and the lower bridge switch tube in the bridge arm not connected to the inductor are turned on or off based on the polarity of the input AC power supply, the PFC circuit operates in the high-frequency PFC mode.

[0036] According to one embodiment of the present disclosure, the upper bridge switch tube and the lower bridge switch tube in the first bridge arm or the second bridge arm are turned on or off based on the polarity of the input AC power supply, including: determining the zero-crossing point of the input AC power supply; at the zero-crossing point, controlling the upper bridge switch tube and the lower bridge switch tube to be turned on or off.

[0037] According to one embodiment of the present disclosure, obtaining the rotational speed of the compressor includes: detecting the rotational speed of the compressor by a rotational speed sensor.

[0038] According to another embodiment of the present disclosure, obtaining the rotational speed of the compressor includes: observing the rotor position of the compressor through a flux observer to obtain the rotational speed of the compressor.

[0039] To achieve the above objectives, a fourth embodiment of the present disclosure provides a computer-readable storage medium on which a control program for a PFC circuit in a refrigeration device is stored. When the program is executed by a processor, the control method for a PFC circuit in a refrigeration device is implemented.

[0040] According to the computer-readable storage medium of the embodiment of the present disclosure, by executing the control method of the PFC circuit in the refrigeration equipment of the above embodiment, it is possible to control the PFC circuit to switch between the synchronous rectification mode and the high-frequency PFC mode by determining the torque of the compressor in the refrigeration equipment. In this way, the switching point of the PFC circuit between the synchronous rectification mode and the high-frequency PFC mode is determined by the torque of the compressor, which has higher real-time performance and accuracy, precise switching, and can avoid unnecessary power loss. While ensuring reliable and stable operation of the motor, it achieves the goals of high efficiency and energy saving.

[0041] To achieve the above objectives, the fifth embodiment of the present disclosure proposes a controller, including: a memory, a processor, and a control program for a PFC circuit in a refrigeration device stored in the memory and executable on the processor. When the processor executes the program, the control method for the PFC circuit in the refrigeration device is implemented.

[0042] According to the controller of the embodiment of the present disclosure, the control program of the PFC circuit in the refrigeration equipment stored in the memory is executed by the processor to implement the above-mentioned control method of the PFC circuit in the refrigeration equipment, so that the PFC circuit can be controlled to switch between the synchronous rectification mode and the high-frequency PFC mode by determining the torque of the compressor in the refrigeration equipment. In this way, the switching point of the PFC circuit between the synchronous rectification mode and the high-frequency PFC mode is determined by the torque of the compressor, which has higher real-time performance and accuracy, precise switching, and can avoid unnecessary power loss. While ensuring reliable and stable operation of the motor, it achieves the goals of high efficiency and energy saving.

[0043] To achieve the above-mentioned objectives, an embodiment of the sixth aspect of the present disclosure proposes a refrigeration device, including: a PFC circuit, the PFC circuit including a synchronous rectification mode and a high-frequency PFC mode; a compressor; and a controller for determining the torque of the compressor and controlling the PFC circuit to switch between the synchronous rectification mode and the high-frequency PFC mode according to the torque of the compressor.

[0044] According to the refrigeration equipment of the embodiment of the present disclosure, the PFC circuit is controlled to switch between the synchronous rectification mode and the high-frequency PFC mode based on the torque of the compressor. In this way, the switching point of the PFC circuit between the synchronous rectification mode and the high-frequency PFC mode is determined by the torque of the compressor, which has higher real-time performance and accuracy, precise switching, and can avoid unnecessary power loss. While ensuring reliable and stable operation of the motor, it achieves the goals of high efficiency and energy saving.

[0045] Additional aspects and advantages of the present disclosure 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 disclosure. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] FIG1 is a hardware topology diagram of a conversion circuit according to an embodiment of the present disclosure;

[0047] FIG2 is a timing diagram of controlling a switch tube in a synchronous rectification mode according to an embodiment of the present disclosure;

[0048] FIG3 is a schematic diagram of current flow in a positive half cycle of an AC power supply in a synchronous rectification mode corresponding to FIG2 according to an embodiment of the present disclosure;

[0049] FIG4 is a schematic diagram of current flow in the negative half cycle of an AC power supply in the synchronous rectification mode corresponding to FIG2 according to an embodiment of the present disclosure;

[0050] FIG5 is a timing diagram of controlling a switch tube in a synchronous rectification mode according to another embodiment of the present disclosure;

[0051] FIG6 is a schematic diagram of current flow in a positive half cycle of an AC power supply in the synchronous rectification mode corresponding to FIG5 according to an embodiment of the present disclosure;

[0052] FIG7 is a schematic diagram of current flow in the negative half cycle of an AC power supply in the synchronous rectification mode corresponding to FIG5 according to one embodiment of the present disclosure;

[0053] FIG8 is a timing diagram of controlling the switch tube in the high-frequency PFC mode according to an embodiment of the present disclosure;

[0054] FIG9 is a schematic diagram of current flow in a positive half cycle of an AC power supply in a high-frequency PFC mode corresponding to FIG8 according to an embodiment of the present disclosure;

[0055] FIG10 is a schematic diagram of current flow in a positive half cycle of an AC power supply in a high-frequency PFC mode corresponding to FIG8 according to an embodiment of the present disclosure;

[0056] FIG11 is a flowchart of determining torque according to one embodiment of the present disclosure;

[0057] FIG12 is a block diagram of an electrical device according to an embodiment of the present disclosure;

[0058] FIG13 is a flow chart of a method for controlling a PFC circuit in a refrigeration device according to an embodiment of the present disclosure;

[0059] FIG14 is a block diagram of a controller according to an embodiment of the present disclosure;

[0060] FIG15 is a block diagram of a refrigeration device according to an embodiment of the present disclosure. DETAILED DESCRIPTION

[0061] The following describes in detail embodiments of the present disclosure, 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 disclosure, and should not be construed as limiting the present disclosure.

[0062] The following describes a conversion circuit, an electrical device, a control method for a PFC circuit in a refrigeration device, a computer-readable storage medium, a controller, and a refrigeration device proposed in embodiments of the present disclosure with reference to the accompanying drawings.

[0063] FIG1 is a hardware topology diagram of a conversion circuit according to an embodiment of the present disclosure.

[0064] As shown in FIG1 , the conversion circuit 300 of the embodiment of the present disclosure is suitable for converting input AC power into DC power to power a motor. The conversion circuit 300 includes: a bridge circuit 310 , an inductor L1 , a capacitor C1 , and a controller 320 .

[0065] The bridge circuit 310 includes a plurality of switch tubes connected in a bridge shape and having an input end and an output end.

[0066] It should be noted that the circuit in which multiple switching tubes are connected in a bridge shape can be a half-bridge circuit, an H-bridge circuit, a three-phase bridge circuit, etc., and there is no specific limitation on this.

[0067] The inductor L1 is connected between the AC power source AC and the input terminal of the bridge circuit 310 . The inductor L1 can store the power supplied from the AC power source AC as energy and release the energy to boost the voltage and improve the power factor.

[0068] The capacitor C1 is connected to the output end of the bridge circuit 310 and is suitable for stabilizing the output voltage of the bridge circuit 310 to provide a DC power supply.

[0069] The controller 320 is configured to obtain the torque of the motor and control multiple switching tubes according to the torque of the motor to switch the working mode of the conversion circuit 300, wherein the working mode of the conversion circuit 300 includes a synchronous rectification mode and a high-frequency PFC mode.

[0070] Specifically, the power provided by the AC power source (AC) is input into the bridge circuit 310 through the inductor L1 for conversion. The capacitor C1 smoothes the voltage output from the bridge circuit 310 into a DC voltage to power the motor. During motor operation, the controller 320 can obtain the motor torque in real time and control the multiple switches based on the motor torque to determine whether the conversion circuit 300 operates in synchronous rectification mode or high-frequency PFC mode. For example, during motor startup, when the motor torque is high, the controller 320 can control the conversion circuit 300 to operate directly in high-frequency PFC mode. During stable operation, when the motor torque is low, the controller 320 can control the conversion circuit 300 to operate in synchronous rectification mode. It should be understood that when the conversion circuit 300 operates in high-frequency PFC mode, the switches are in high-frequency operation, resulting in significant switching losses. When the conversion circuit 300 operates in synchronous rectification mode, the switches are in low-frequency operation, resulting in lower switching losses.

[0071] Therefore, the conversion circuit 300 of the embodiment of the present disclosure, in the process of converting the input AC power supply AC into DC power supply to power the motor, obtains the actual torque of the motor and realizes rapid and accurate switching between the synchronous rectification mode and the high-frequency PFC mode based on the torque of the motor. It has high real-time performance and precise switching, avoids unnecessary power loss, and achieves the purpose of high efficiency and energy saving while ensuring reliable and stable operation of the motor.

[0072] According to one embodiment of the present disclosure, as shown in FIG1 , a plurality of switching tubes are configured to form a first bridge arm 311 and a second bridge arm 312 connected in parallel, with the midpoint of the first bridge arm 311 and the midpoint of the second bridge arm 312 serving as input ends, and both ends of the first bridge arm 311 or the second bridge arm 312 serving as output ends, and the midpoint of the first bridge arm 311 is connected to the AC power supply AC through an inductor L1.

[0073] Specifically, as shown in FIG1 , the first bridge arm 311 includes an upper bridge switch Q1 and a lower bridge switch Q2 connected in series, and the second bridge arm 312 includes an upper bridge switch Q3 and a lower bridge switch Q4 connected in series. The upper bridge switch Q1 and the lower bridge switch Q2 in the first bridge arm 311, and the upper bridge switch Q3 and the lower bridge switch Q4 in the second bridge arm 312 form a bridge circuit 310. The upper bridge switch Q1 and the lower bridge switch Q2 in the first bridge arm 311, and the upper bridge switch Q3 and the lower bridge switch Q4 in the second bridge arm 312 all have parasitic diodes that enable freewheeling. One end of an inductor L1 is connected to one end of an AC power source AC, and the other end of the inductor L1 is connected to the connection point between the upper bridge switch Q1 and the lower bridge switch Q2 in the first bridge arm 311. The positive electrode of capacitor C1 is connected to the drain of the upper bridge switch Q1 in the first bridge arm 311 and the drain of the upper bridge switch Q3 in the second bridge arm 312, and the negative electrode is connected to the source of the lower bridge switch Q2 in the first bridge arm 311 and the source of the lower bridge switch Q4 in the second bridge arm 312. Controller 320 is connected to the control terminal of each switch. Controller 320 can also collect the voltage VAC of the input AC power supply AC, the current IAC flowing through inductor L1, and the bus voltage VDC.

[0074] According to one embodiment of the present disclosure, the upper bridge switch Q1 and the lower bridge switch Q2 in the first bridge arm 311 are configured as fast switches, while the upper bridge switch Q3 and the lower bridge switch Q4 in the second bridge arm 312 are configured as slow switches. As a result, the reverse recovery time of the upper bridge switch Q1 and the lower bridge switch Q2 in the first bridge arm 311 is faster than the reverse recovery time of the upper bridge switch Q3 and the lower bridge switch Q4 in the second bridge arm 312. This allows the controller 320 to control the upper bridge switch Q1 and the lower bridge switch Q2 in the first bridge arm 311 to perform high-frequency switching in the high-frequency PFC mode.

[0075] Optionally, in some embodiments, the switching element in the fast tube is a silicon carbide MOSFET or a gallium nitride MOSFET.

[0076] According to one embodiment of the present disclosure, when the conversion circuit 300 operates in a synchronous rectification mode, the upper bridge switch Q1 and the lower bridge switch Q2 in the first bridge arm 311 are turned on or off based on the polarity of the alternating current power supply AC, and the upper bridge switch Q3 and the lower bridge switch Q4 in the second bridge arm 312 are turned on or off based on the magnitude and polarity of the current flowing through the inductor L1.

[0077] Specifically, when the conversion circuit 300 operates in synchronous rectification mode, the controller 320 can control the upper bridge switch Q1 and the lower bridge switch Q2 in the first bridge arm 311 to turn on or off according to the polarity of the AC power supply AC, and can control the upper bridge switch Q3 and the lower bridge switch Q4 in the second bridge arm 312 to turn on or off according to the magnitude and polarity of the current flowing through the inductor L1. The timing of controlling the switch tubes in the synchronous rectification mode is shown in Figure 2, where the voltage of the AC power supply AC is VAC and the current of the inductor L1 is IAC. 1 and 2 , during the positive half-cycle of the AC power source AC, the controller 320 controls the upper bridge switch Q1 in the first bridge arm 311 to turn on and the lower bridge switch Q2 in the first bridge arm 311 to turn off. Thus, the AC power source AC, the inductor L1, the upper bridge switch Q1 in the first bridge arm 311, the capacitor C1, the parasitic diode of the lower bridge switch Q4 in the second bridge arm 312, and the AC power source AC form a loop. When the current IAC crosses zero, the controller 320 controls the lower bridge switch Q4 in the second bridge arm 312 to turn on. Thus, the AC power source AC, the inductor L1, the upper bridge switch Q1 in the first bridge arm 311, the capacitor C1, the lower bridge switch Q4 in the second bridge arm 312, and the AC power source AC form a loop. The flow direction of the current IAC is shown by the dotted line in FIG3 . This prevents the parasitic diode of the lower bridge switch Q4 in the second bridge arm 312 from burning out and reduces turn-on loss. Similarly, during the negative half-cycle of the AC power source AC, the controller 320 controls the lower bridge switch Q2 in the first bridge arm 311 to turn on and the upper bridge switch Q1 in the first bridge arm 311 to turn off. The AC power source AC, the parasitic diode of the upper bridge switch Q3 in the second bridge arm 312, the capacitor C1, the lower bridge switch Q2 in the first bridge arm 311, the inductor L1, and the AC power source AC form a loop. When the current IAC passes through zero, the controller 320 controls the upper bridge switch Q3 in the second bridge arm 312 to turn on. The flow direction of the current IAC is shown by the dotted line in FIG4 . The AC power source AC, the upper bridge switch Q3 in the second bridge arm 312, the capacitor C1, the lower bridge switch Q2 in the first bridge arm 311, the inductor L1, and the AC power source AC form a loop, and the current IAC flows through the loop. This prevents the parasitic diode of the upper bridge switch Q3 in the second bridge arm 312 from burning out and reduces turn-on loss.

[0078] According to another embodiment of the present disclosure, when the conversion circuit 300 operates in a synchronous rectification mode, the upper bridge switch Q3 and the lower bridge switch Q4 in the second bridge arm 312 are turned on or off based on the polarity of the alternating current power supply AC, and the upper bridge switch Q1 and the lower bridge switch Q2 in the first bridge arm 311 are turned on or off based on the magnitude and polarity of the current flowing through the inductor L1.

[0079] Specifically, when the conversion circuit 300 operates in synchronous rectification mode, the controller 320 can control the upper bridge switch Q3 and the lower bridge switch Q4 in the second bridge arm 312 to be turned on or off according to the polarity of the AC power supply AC, and can control the upper bridge switch Q1 and the lower bridge switch Q2 in the first bridge arm 311 to be turned on or off according to the magnitude and polarity of the current flowing through the inductor L1. The timing of controlling the switch tubes in the synchronous rectification mode is shown in Figure 5, where the voltage of the AC power supply AC is VAC and the current of the inductor L1 is IAC. 1 and 5 , during the positive half-cycle of the AC power source AC, the controller 320 controls the upper bridge switch Q3 in the second bridge arm 312 to turn on and the lower bridge switch Q4 in the second bridge arm 312 to turn off. Thus, the AC power source AC, the inductor L1, the parasitic diode of the lower bridge switch Q2 in the first bridge arm 311, the capacitor C1, the upper bridge switch Q3 in the second bridge arm 312, and the AC power source AC form a loop. When the current IAC crosses zero, the controller 320 controls the lower bridge switch Q2 in the first bridge arm 311 to turn on. Thus, the AC power source AC, the inductor L1, the lower bridge switch Q2 in the first bridge arm 311, the capacitor C1, the upper bridge switch Q3 in the second bridge arm 312, and the AC power source AC form a loop. The flow direction of the current IAC is shown by the dotted line in FIG6 . This prevents the parasitic diode of the lower bridge switch Q2 in the first bridge arm 311 from burning out and reduces turn-on losses. Similarly, during the negative half-cycle of the AC power source AC, the controller 320 controls the lower bridge switch Q4 in the second bridge arm 312 to turn on and the upper bridge switch Q3 in the second bridge arm 312 to turn off. The AC power source AC, the lower bridge switch Q4 in the second bridge arm 312, the capacitor C1, the parasitic diode of the upper bridge switch Q1 in the first bridge arm 311, the inductor L1, and the AC power source AC form a loop. When the current IAC passes through zero, the controller 320 controls the upper bridge switch Q1 in the first bridge arm 311 to turn on. The flow direction of the current IAC is shown by the dotted line in FIG7 . The AC power source AC, the lower bridge switch Q4 in the second bridge arm 312, the capacitor C1, the upper bridge switch Q1 in the first bridge arm 311, the inductor L1, and the AC power source AC form a loop, and the current IAC flows through the loop. This prevents the parasitic diode of the upper bridge switch Q1 in the first bridge arm 311 from burning out and reduces turn-on loss.

[0080] According to one embodiment of the present disclosure, when the conversion circuit 300 operates in a high-frequency PFC mode, the upper bridge switch Q3 and the lower bridge switch Q4 in the second bridge arm 312 are turned on or off based on the polarity of the alternating current power supply AC, and the upper bridge switch Q1 and the lower bridge switch Q2 in the first bridge arm 311 are alternately turned on or off based on a set frequency.

[0081] Specifically, when the conversion circuit 300 operates in the high-frequency PFC mode, the controller 320 can control the upper bridge switch Q3 and the lower bridge switch Q4 in the second bridge arm 312 to turn on or off according to the polarity of the AC power supply AC, and can control the upper bridge switch Q3 and the lower bridge switch Q4 in the second bridge arm 312 to turn on or off according to the magnitude and polarity of the current flowing through the inductor L1. The timing of controlling the switch tubes in the high-frequency PFC mode is shown in Figure 8. 1 and 8 , during the positive half cycle of the AC power supply AC, the controller 320 controls the lower bridge switch Q4 in the second bridge arm 312 to turn on and the upper bridge switch Q3 in the second bridge arm 312 to turn off, and first controls the lower bridge switch Q2 in the first bridge arm 311 to turn on and the upper bridge switch Q1 to turn off. At this time, the AC power supply AC, the inductor L1, the lower bridge switch Q2 in the first bridge arm 311, the lower bridge switch Q4 in the second bridge arm 312, and the AC power supply AC form a loop. The flow direction of the current IAC is shown by the dotted line in FIG9 . The AC power supply A C charges inductor L1; then controls the upper bridge switch Q1 in first arm 311 to turn on and the lower bridge switch Q2 to turn off. The AC power source AC, inductor L1, upper bridge switch Q1 in first arm 311, capacitor C1, lower bridge switch Q4 in second arm 312, and AC power source AC form a loop. The flow of current IAC is shown by the dotted line in Figure 10. The charge stored in inductor L1 is released and superimposed with the voltage of AC power source AC to boost and charge capacitor C1, thereby boosting the voltage and improving the power factor. In this cycle, controller 320 controls the upper bridge switch Q1 and lower bridge switch Q2 in first arm 311 to alternately turn on and off based on the set frequency.

[0082] During the negative half cycle of the AC power supply AC, the controller 320 controls the upper bridge switch Q3 in the second bridge arm 312 to turn on and the lower bridge switch Q4 in the second bridge arm 312 to turn off, and first controls the upper bridge switch Q1 in the first bridge arm 311 to turn on and the lower bridge switch Q2 to turn off. Although not shown in the figure, at this time, the AC power supply AC, the upper bridge switch Q3 in the second bridge arm 312, the upper bridge switch Q1 in the first bridge arm 311, the inductor L1 and the AC power supply AC form a loop, and the AC power supply AC has an effect on the inductor L1. The controller 320 then controls the lower bridge switch Q2 in the first bridge arm 311 to turn on and the upper bridge switch Q1 to turn off. Although not shown, the AC power source AC, the upper bridge switch Q3 in the second bridge arm 312, the capacitor C1, the lower bridge switch Q2 in the first bridge arm 311, the inductor L1, and the AC power source AC form a loop. The energy stored in the inductor L1 is released and superimposed with the voltage of the AC power source AC to boost and charge the capacitor C1, thereby boosting the voltage and improving the power factor. In this cycle, the controller 320 controls the upper bridge switch Q1 and the lower bridge switch Q2 in the first bridge arm 311 to alternately turn on and off based on the set frequency.

[0083] According to one embodiment of the present disclosure, the upper bridge switch tube and the lower bridge switch tube in the first bridge arm 311 or the second bridge arm 312 are turned on or off based on the polarity of the input AC power supply AC, including: determining the zero crossing point of the input AC power supply AC; at the zero crossing point, controlling the upper bridge switch tube and the lower bridge switch tube to be turned on or off.

[0084] Specifically, the controller 320 can detect the voltage of the AC power source AC in real time to determine the zero-crossing point of the AC power source AC. The controller 320 controls the upper bridge switch tube and the lower bridge switch tube to turn on or off at the zero-crossing point.

[0085] According to one embodiment of the present disclosure, when the conversion circuit 300 operates in a synchronous rectification mode, if the upper bridge switch Q1 and the lower bridge switch Q2 in the first bridge arm 311 are turned on or off based on the polarity of the alternating current power supply AC, the first bridge arm 311 is used as a zero-voltage turn-on bridge arm; if the upper bridge switch Q3 and the lower bridge switch Q4 in the second bridge arm 312 are turned on or off based on the polarity of the alternating current power supply AC, the second bridge arm 312 is used as a zero-voltage turn-on bridge arm.

[0086] That is, when the conversion circuit 300 operates in synchronous rectification mode, when the upper bridge switch and the lower bridge switch in a bridge arm are turned on or off based on the polarity of the AC power supply AC, the bridge arm is a zero voltage turn-on bridge arm.

[0087] According to an embodiment of the present disclosure, the controller 320 is further configured to determine one of the first bridge arm 311 and the second bridge arm 312 as the zero voltage turn-on bridge arm according to the total operating time of the first bridge arm 311 and the total operating time of the second bridge arm 312 .

[0088] Specifically, as shown in Figures 2 and 5, when the conversion circuit 300 operates in synchronous rectification mode, the operating time of the zero-voltage-on bridge arm is longer than the operating time of the non-zero-voltage-on bridge arm. The controller 320 can count the total operating time of the two bridge arms, compare the total operating time of the two bridge arms, and control the bridge arm with the longer total operating time as the zero-voltage-on bridge arm. This balances the operating time of the two bridge arms, making the operating time of the switches in the bridge arms more consistent, thereby increasing the service life of the conversion circuit 300.

[0089] According to another embodiment of the present disclosure, the controller 320 is further configured to determine the zero voltage turn-on bridge arm when operating in the synchronous rectification mode this time based on the zero voltage turn-on bridge arm when the conversion circuit 300 last operated in the synchronous rectification mode.

[0090] According to one embodiment of the present disclosure, the controller 320 is further configured to control the conversion circuit 300 to switch to a high-frequency PFC mode when the torque is greater than or equal to a first preset value; and to control the conversion circuit 300 to switch to a synchronous rectification mode when the torque is less than the first preset value. The first preset value can be calibrated based on actual conditions and is not limited here.

[0091] Specifically, after obtaining the torque of the motor, the controller 320 can compare the torque with a first preset value. When the torque is greater than or equal to the first preset value, the controller 320 controls the conversion circuit 300 to switch to a high-frequency PFC mode for operation; when the torque is less than the first preset value, the controller 320 controls the conversion circuit 300 to switch to a synchronous rectification mode for operation.

[0092] According to another embodiment of the present disclosure, the controller 320 is further configured to obtain the motor speed, determine the torque based on the speed difference between the motor speed and the target speed, and determine the product value between the motor speed and the torque. When the product value is greater than or equal to a second preset value, the controller 320 controls the conversion circuit 300 to switch to the high-frequency PFC mode for operation; when the product value is less than the second preset value, the controller 320 controls the conversion circuit 300 to switch to the synchronous rectification mode for operation. The second preset value can be calibrated according to actual conditions and is not limited here.

[0093] Specifically, as shown in Figure 11, after obtaining the speed of the motor, the controller 320 can subtract the speed from the target speed, and then perform PI control on the speed difference of the motor to obtain the torque of the motor, and multiply the speed of the compressor by the torque, and compare the product value with the second preset value. When the product value is greater than or equal to the second preset value, the controller 320 controls the conversion circuit 300 to switch to the high-frequency PFC mode for operation; when the product value is less than the second preset value, the controller 320 controls the conversion circuit 300 to switch to the synchronous rectification mode for operation.

[0094] In some embodiments of the present disclosure, the Te value can also be calculated using the formula Te = 3 / 2*P[Ke*Iq+(Ld-Lq)Id*Iq], where P is the number of motor pole pairs, Ke is the motor back EMF, Ld is the motor D-axis inductance, Lq is the motor Q-axis inductance, Id is the motor D-axis control current, and Iq is the motor Q-axis control current. The controller can obtain the motor's pole pair number P, motor back EMF Ke, motor D-axis inductance Ld, motor Q-axis inductance Lq, motor D-axis control current Id, and motor Q-axis control current Iq, and substitute these into the above formula for calculation to obtain the motor's torque.

[0095] To sum up, according to the conversion circuit of the embodiment of the present invention, in the process of converting the input AC power supply into DC power supply to power the motor, the actual torque of the motor is obtained, and based on the torque of the motor, fast and accurate switching between the synchronous rectification mode and the high-frequency PFC mode is achieved. It has high real-time performance and precise switching, avoids unnecessary power loss, and achieves the purpose of high efficiency and energy saving while ensuring reliable and stable operation of the motor.

[0096] Corresponding to the above embodiments, the present disclosure also proposes an electrical device.

[0097] FIG12 is a block diagram of an electrical device according to an embodiment of the present disclosure.

[0098] As shown in FIG12 , the electrical device 400 according to the embodiment of the present disclosure includes: a motor 410 ; and a conversion circuit 300 according to the above embodiment, the conversion circuit being suitable for converting an input AC power supply into a DC power supply to power the motor.

[0099] According to the electrical equipment of the embodiment of the present disclosure, based on the conversion circuit described in the above embodiment, in the process of converting the input AC power supply into DC power supply to power the motor, it is possible to quickly and accurately switch between the synchronous rectification mode and the high-frequency PFC mode based on the torque of the motor. It has high real-time performance and precise switching, avoids unnecessary power loss, and achieves the goals of high efficiency and energy saving while ensuring reliable and stable operation of the motor.

[0100] Corresponding to the above embodiment, the present disclosure further proposes a method for controlling a PFC circuit in a refrigeration device.

[0101] FIG13 is a flow chart of a method for controlling a PFC circuit in a refrigeration device according to an embodiment of the present disclosure.

[0102] In some embodiments of the present disclosure, a PFC circuit can adjust the power factor of a refrigeration device and increase the DC bus voltage, which primarily powers the compressor and fan motor. The PFC circuit includes a synchronous rectification mode and a high-frequency PFC mode.

[0103] When the refrigeration equipment starts up, the input power is high, so the high-frequency PFC mode is directly activated. However, in some low-power states, the high-frequency PFC mode is not required. Switching from the high-frequency PFC mode to the synchronous rectification mode can meet the power factor adjustment requirements of the refrigeration equipment. When the PFC circuit operates in high-frequency PFC mode, the control tube operates in high-frequency mode, resulting in large switching losses. When the PFC circuit operates in synchronous rectification mode, the control tube operates in low-frequency mode, resulting in smaller switching losses.

[0104] As shown in FIG13 , a method for controlling a PFC circuit in a refrigeration device according to an embodiment of the present disclosure may include the following steps:

[0105] S1, determine the torque of the compressor in the refrigeration equipment.

[0106] S2, controlling the PFC circuit to switch between a synchronous rectification mode and a high-frequency PFC mode according to the torque of the compressor.

[0107] The control method of the PFC circuit in the refrigeration equipment of the embodiment of the present disclosure controls the PFC circuit to switch between the synchronous rectification mode and the high-frequency PFC mode by determining the torque of the compressor in the refrigeration equipment. In this way, the switching point of the PFC circuit between the synchronous rectification mode and the high-frequency PFC mode is determined by the torque of the compressor. This method has higher real-time performance and accuracy, precise switching, and can avoid unnecessary power loss. While ensuring reliable and stable operation of the motor, it achieves the goals of high efficiency and energy saving.

[0108] According to one embodiment of the present disclosure, controlling a PFC circuit to switch between a synchronous rectification mode and a high-frequency PFC mode based on compressor torque includes: controlling the PFC circuit to switch to the high-frequency PFC mode when the torque is greater than or equal to a first preset value; and controlling the PFC circuit to switch to the synchronous rectification mode when the torque is less than the first preset value. The first preset value can be set based on specific parameters of the refrigeration equipment and is not limited here.

[0109] According to one embodiment of the present disclosure, determining the torque of a compressor in a refrigeration device includes: acquiring a rotational speed of the compressor; and determining the torque of the compressor based on a rotational speed difference between the rotational speed of the compressor and a target rotational speed.

[0110] According to one embodiment of the present disclosure, obtaining the rotational speed of the compressor includes: obtaining the rotational speed of the compressor through a rotational speed sensor.

[0111] That is to say, by detecting the compressor through the rotation speed sensor, the rotation speed of the compressor can be obtained in real time. Wherein, the rotation speed sensor can be a Hall sensor.

[0112] According to another embodiment of the present disclosure, obtaining the rotational speed of the compressor includes: observing the rotor position of the compressor through a flux observer to obtain the rotational speed of the compressor.

[0113] Specifically, the flux observer can identify the stator flux angle and magnitude, determine the rotor position, and thus infer the compressor motor rotor speed, thereby obtaining the compressor speed. Furthermore, after obtaining the compressor speed, the controller can subtract the speed from the target speed and then perform PI control on the compressor speed difference to obtain the compressor torque. The controller compares the torque with a first preset value. When the torque is greater than or equal to the first preset value, the controller switches the PFC circuit to high-frequency PFC mode. When the torque is less than the first preset value, the controller switches the PFC circuit to synchronous rectification mode.

[0114] In some embodiments of the present disclosure, the Te value can also be calculated using the formula Te = 3 / 2*P[Ke*Iq+(Ld-Lq)Id*Iq], where P is the number of motor pole pairs, Ke is the motor back EMF, Ld is the motor D-axis inductance, Lq is the motor Q-axis inductance, Id is the motor D-axis control current, and Iq is the motor Q-axis control current. The controller can obtain the compressor's pole pair number P, back EMF Ke, D-axis inductance Ld, Q-axis inductance Lq, D-axis control current Id, and Q-axis control current Iq, and substitute these into the above formula to calculate the compressor's torque.

[0115] According to another embodiment of the present disclosure, controlling a PFC circuit to switch between a synchronous rectification mode and a high-frequency PFC mode based on compressor torque includes: determining a product value between the compressor speed and torque; controlling the PFC circuit to switch to the high-frequency PFC mode when the product value is greater than or equal to a second preset value; and controlling the PFC circuit to switch to the synchronous rectification mode when the product value is less than the second preset value. The second preset value can be set based on specific parameters of the refrigeration equipment and is not limited herein.

[0116] Specifically, after obtaining the speed of the compressor, the controller can subtract the speed from the target speed, and then perform PI control on the speed difference of the compressor to obtain the torque of the compressor, and multiply the actual speed of the compressor by the torque, and compare the product value with a second preset value. When the product value is greater than or equal to the second preset value, the controller controls the PFC circuit to switch to the high-frequency PFC mode for operation; when the product value is less than the second preset value, the controller controls the PFC circuit to switch to the synchronous rectification mode for operation.

[0117] According to one embodiment of the present disclosure, a PFC circuit includes an inductor and a bridge circuit, the bridge circuit includes a plurality of switching tubes, the plurality of switching tubes being configured to form a first bridge arm and a second bridge arm connected in parallel, one of the first bridge arm and the second bridge arm being connected to the inductor, wherein the upper bridge switching tube and the lower bridge switching tube in the first bridge arm are turned on or off based on the polarity of the input AC power supply, and the upper bridge switching tube and the lower bridge switching tube in the second bridge arm are turned on or off based on the magnitude and polarity of the current flowing through the inductor, the PFC circuit operates in a synchronous rectification mode; or, in the second bridge arm, The PFC circuit operates in a synchronous rectification mode when the upper bridge switch tube and the lower bridge switch tube are turned on or off based on the polarity of the input AC power supply, and the upper bridge switch tube and the lower bridge switch tube in the first bridge arm are turned on or off based on the magnitude and polarity of the current flowing through the inductor; the PFC circuit operates in a high-frequency PFC mode when the upper bridge switch tube and the lower bridge switch tube in the bridge arm connected to the inductor are alternately turned on or off based on a set frequency, and the upper bridge switch tube and the lower bridge switch tube in the bridge arm not connected to the inductor are turned on or off based on the polarity of the input AC power supply.

[0118] According to one embodiment of the present disclosure, the upper bridge switch tube and the lower bridge switch tube in the first bridge arm or the second bridge arm are turned on or off based on the polarity of the input AC power supply, including: determining the zero-crossing point of the input AC power supply; at the zero-crossing point, controlling the upper bridge switch tube and the lower bridge switch tube to be turned on or off.

[0119] It should be noted that the above-mentioned PFC circuit is equivalent to the conversion circuit of the embodiment of the first aspect of the present disclosure, and the above-mentioned compressor is equivalent to the motor. The specific working principle of the PFC circuit can refer to the specific description of the conversion circuit of the embodiment of the first aspect of the present disclosure, and will not be repeated here.

[0120] In summary, according to the control method of the PFC circuit in the refrigeration equipment of the embodiment of the present disclosure, the torque of the compressor in the refrigeration equipment is determined to control the PFC circuit to switch between the synchronous rectification mode and the high-frequency PFC mode. In this way, the switching point of the PFC circuit between the synchronous rectification mode and the high-frequency PFC mode is determined by the torque of the compressor, which has higher real-time performance and accuracy, precise switching, and can avoid unnecessary power loss. While ensuring the reliable and stable operation of the motor, it achieves the purpose of high efficiency and energy saving.

[0121] Corresponding to the above embodiments, the present disclosure also proposes a computer-readable storage medium.

[0122] The computer-readable storage medium of the embodiment of the present disclosure stores a control program for a PFC circuit in a refrigeration device. When the program is executed by a processor, the control method for a PFC circuit in a refrigeration device is implemented.

[0123] According to the computer-readable storage medium of the embodiment of the present disclosure, by executing the control method of the PFC circuit in the refrigeration equipment of the above embodiment, it is possible to control the PFC circuit to switch between the synchronous rectification mode and the high-frequency PFC mode by determining the torque of the compressor in the refrigeration equipment. In this way, the switching point of the PFC circuit between the synchronous rectification mode and the high-frequency PFC mode is determined by the torque of the compressor, which has higher real-time performance and accuracy, precise switching, and can avoid unnecessary power loss. While ensuring reliable and stable operation of the motor, it achieves the goals of high efficiency and energy saving.

[0124] Corresponding to the above embodiments, the present disclosure also proposes a controller.

[0125] FIG14 is a block diagram of a controller according to an embodiment of the present disclosure.

[0126] As shown in FIG14 , the controller 200 of the embodiment of the present disclosure includes: a memory 210, a processor 220, and a control program for the PFC circuit in the refrigeration equipment stored in the memory 210 and executable on the processor 220. When the processor 220 executes the program, the control method for the PFC circuit in the refrigeration equipment described above is implemented.

[0127] According to the controller of the embodiment of the present disclosure, the control program of the PFC circuit in the refrigeration equipment stored in the memory is executed by the processor to implement the above-mentioned control method of the PFC circuit in the refrigeration equipment, so that the PFC circuit can be controlled to switch between the synchronous rectification mode and the high-frequency PFC mode by determining the torque of the compressor in the refrigeration equipment. In this way, the switching point of the PFC circuit between the synchronous rectification mode and the high-frequency PFC mode is determined by the torque of the compressor, which has higher real-time performance and accuracy, precise switching, and can avoid unnecessary power loss. While ensuring reliable and stable operation of the motor, it achieves the goals of high efficiency and energy saving.

[0128] Corresponding to the above embodiment, the present disclosure also proposes a refrigeration device.

[0129] FIG15 is a block diagram of a refrigeration device according to an embodiment of the present disclosure.

[0130] As shown in FIG. 15 , the refrigeration device 100 according to the embodiment of the present disclosure may include: a PFC circuit 110 , a compressor 120 , and a controller 130 .

[0131] The PFC circuit 110 includes a synchronous rectification mode and a high-frequency PFC mode. The controller 130 is configured to determine the torque of the compressor and control the PFC circuit to switch between the synchronous rectification mode and the high-frequency PFC mode according to the torque of the compressor.

[0132] According to one embodiment of the present disclosure, the controller 130 controls the PFC circuit to switch between the synchronous rectification mode and the high-frequency PFC mode according to the torque of the compressor. Specifically, when the torque is greater than or equal to a first preset value, the controller 130 controls the PFC circuit to switch to the high-frequency PFC mode for operation; when the torque is less than the first preset value, the controller 130 controls the PFC circuit to switch to the synchronous rectification mode for operation.

[0133] According to an embodiment of the present disclosure, the controller 130 determines the torque of the compressor in the refrigeration equipment, specifically for obtaining the speed of the compressor; and determining the torque of the compressor according to the speed difference between the speed of the compressor and the target speed.

[0134] According to another embodiment of the present disclosure, the controller 130 controls the PFC circuit to switch between the synchronous rectification mode and the high-frequency PFC mode according to the torque of the compressor, and is specifically used to determine the product value between the speed and torque of the compressor; when the product value is greater than or equal to a second preset value, the PFC circuit is controlled to switch to the high-frequency PFC mode for operation; when the product value is less than the second preset value, the PFC circuit is controlled to switch to the synchronous rectification mode for operation.

[0135] According to one embodiment of the present disclosure, a PFC circuit includes an inductor and a bridge circuit, the bridge circuit includes a plurality of switching tubes, the plurality of switching tubes being configured to form a first bridge arm and a second bridge arm connected in parallel, one of the first bridge arm and the second bridge arm being connected to the inductor, wherein the upper bridge switching tube and the lower bridge switching tube in the first bridge arm are turned on or off based on the polarity of the input AC power supply, and the upper bridge switching tube and the lower bridge switching tube in the second bridge arm are turned on or off based on the magnitude and polarity of the current flowing through the inductor, the PFC circuit operates in a synchronous rectification mode; or, in the second bridge arm, The PFC circuit operates in a synchronous rectification mode when the upper bridge switch tube and the lower bridge switch tube are turned on or off based on the polarity of the input AC power supply, and the upper bridge switch tube and the lower bridge switch tube in the first bridge arm are turned on or off based on the magnitude and polarity of the current flowing through the inductor; the PFC circuit operates in a high-frequency PFC mode when the upper bridge switch tube and the lower bridge switch tube in the bridge arm connected to the inductor are alternately turned on or off based on a set frequency, and the upper bridge switch tube and the lower bridge switch tube in the bridge arm not connected to the inductor are turned on or off based on the polarity of the input AC power supply.

[0136] According to one embodiment of the present disclosure, the upper bridge switch tube and the lower bridge switch tube in the first bridge arm or the second bridge arm are turned on or off based on the polarity of the input AC power supply, including: determining the zero-crossing point of the input AC power supply; at the zero-crossing point, controlling the upper bridge switch tube and the lower bridge switch tube to be turned on or off.

[0137] According to an embodiment of the present disclosure, the controller 130 obtains the rotation speed of the compressor, specifically, detects the rotation speed of the compressor through a rotation speed sensor.

[0138] According to another embodiment of the present disclosure, controller 130 obtains the compressor speed. Specifically, it is configured to observe the compressor rotor position using a flux observer to obtain the compressor speed. It should be noted that for details not disclosed in the refrigeration device of the present embodiment, please refer to the details disclosed in the control method of the PFC circuit in the refrigeration device of the present embodiment, and the details are not repeated here.

[0139] According to the refrigeration equipment of the embodiment of the present disclosure, the PFC circuit is controlled to switch between the synchronous rectification mode and the high-frequency PFC mode based on the torque of the compressor. In this way, the switching point of the PFC circuit between the synchronous rectification mode and the high-frequency PFC mode is determined by the torque of the compressor, which has higher real-time performance and accuracy, precise switching, and can avoid unnecessary power loss. While ensuring reliable and stable operation of the motor, it achieves the goals of high efficiency and energy saving.

[0140] It should be noted that the logic and / or steps represented in the flowcharts or otherwise described herein, for example, can be considered as a sequenced list of executable instructions for implementing the logical functions, and can be embodied in any computer-readable medium for use by, or in conjunction with, an instruction execution system, apparatus, or device (e.g., a computer-based system, a system including a processor, or other system that can fetch and execute instructions from an instruction execution system, apparatus, or device). For purposes of this specification, a "computer-readable medium" can be any device that can contain, store, communicate, propagate, or transport a program for use by, or in conjunction with, an instruction execution system, apparatus, or device. More specific examples (non-exhaustive list) of computer-readable media include the following: an electrical connection with one or more wires (electronic device), a portable computer disk cartridge (magnetic device), random access memory (RAM), read-only memory (ROM), erasable and programmable read-only memory (EPROM or flash memory), fiber optic devices, and portable compact disc read-only memory (CDROM). Furthermore, 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 it in another suitable manner if necessary, and then storing it in a computer memory.

[0141] It should be understood that various parts of the present disclosure can be implemented using hardware, software, firmware, or a combination thereof. In the above embodiments, multiple steps or methods can be implemented using software or firmware stored in a memory and executed by a suitable instruction execution system. For example, if implemented using hardware, as in another embodiment, any one of the following technologies known in the art or a combination thereof can be used to implement: a discrete logic circuit having a logic gate circuit for implementing a logic function on a data signal, an application-specific integrated circuit having a suitable combination of logic gate circuits, a programmable gate array (PGA), a field programmable gate array (FPGA), etc.

[0142] Throughout this specification, reference to terms such as "one embodiment," "some embodiments," "examples," "specific examples," or "some examples" means that a specific feature, structure, material, or characteristic described in conjunction with that embodiment or example is included in at least one embodiment or example of the present disclosure. In this specification, schematic representations of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

[0143] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features being referred to. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one such feature. Throughout the present disclosure, "plurality" means at least two, such as two, three, etc., unless otherwise specifically defined.

[0144] In this disclosure, unless otherwise expressly specified or limited, terms such as "installed," "connected," "connect," and "fixed" should be understood in a broad sense. For example, they may refer to fixed connections, detachable connections, or integration; mechanical connections or electrical connections; direct connections or indirect connections through an intermediate medium; and internal communication between two components or interaction between two components, unless otherwise expressly limited. Those skilled in the art will understand the specific meanings of the above terms in this disclosure based on specific circumstances.

[0145] Although the embodiments of the present disclosure have been shown and described above, it is understood that the above embodiments are illustrative and are not to be construed as limitations on the present disclosure. A person skilled in the art may change, modify, replace and vary the above embodiments within the scope of the present disclosure.

Claims

1. A conversion circuit, adapted to convert an input AC power supply into a DC power supply to power the motor, the conversion circuit comprising: A bridge circuit, the bridge circuit comprising a plurality of switch tubes, the plurality of switch tubes being connected in a bridge shape and having an input end and an output end; an inductor connected between the AC power source and the input terminal; A capacitor, connected to the output end, suitable for stabilizing the output voltage of the bridge circuit to provide the DC power supply; The controller is configured to obtain the torque of the motor and control the multiple switch tubes according to the torque of the motor to switch the working mode of the conversion circuit, wherein the working mode of the conversion circuit includes a synchronous rectification mode and a high-frequency PFC mode.

2. The conversion circuit according to claim 1, wherein: The multiple switching tubes are configured to form a first bridge arm and a second bridge arm connected in parallel, the midpoint of the first bridge arm and the midpoint of the second bridge arm serve as the input end, the two ends of the first bridge arm or the second bridge arm serve as the output end, and the midpoint of the first bridge arm is connected to the AC power supply through the inductor.

3. The conversion circuit according to claim 2, wherein: The upper bridge switch tube and the lower bridge switch tube in the first bridge arm are configured as fast tubes, and the upper bridge switch tube and the lower bridge switch tube in the second bridge arm are configured as slow tubes.

4. The conversion circuit according to claim 3, wherein: The switch element in the fast tube is a silicon carbide MOSFET or a gallium nitride MOSFET.

5. The conversion circuit according to any one of claims 2 to 4, wherein: When the conversion circuit operates in the synchronous rectification mode, the upper bridge switch tube and the lower bridge switch tube in the first bridge arm are turned on or off based on the polarity of the AC power supply, and the upper bridge switch tube and the lower bridge switch tube in the second bridge arm are turned on or off based on the magnitude and polarity of the current flowing through the inductor.

6. The conversion circuit according to any one of claims 2 to 4, wherein: When the conversion circuit operates in the synchronous rectification mode, the upper bridge switch tube and the lower bridge switch tube in the second bridge arm are turned on or off based on the polarity of the AC power supply, and the upper bridge switch tube and the lower bridge switch tube in the first bridge arm are turned on or off based on the magnitude and polarity of the current flowing through the inductor.

7. The conversion circuit according to any one of claims 3 to 6, wherein: When the conversion circuit operates in the high-frequency PFC mode, the upper bridge switch tube and the lower bridge switch tube in the second bridge arm are turned on or off based on the polarity of the AC power supply, and the upper bridge switch tube and the lower bridge switch tube in the first bridge arm are turned on or off alternately based on the set frequency.

8. The conversion circuit according to any one of claims 2 to 7, wherein: When the conversion circuit operates in the synchronous rectification mode, If the upper bridge switch tube and the lower bridge switch tube in the first bridge arm are turned on or off based on the polarity of the AC power supply, the first bridge arm is used as a zero voltage turned-on bridge arm; If the upper bridge switch tube and the lower bridge switch tube in the second bridge arm are turned on or off based on the polarity of the AC power supply, the second bridge arm is used as a zero-voltage turned-on bridge arm.

9. The conversion circuit according to claim 8, wherein: The controller is further configured to determine one of the first bridge arm and the second bridge arm as the zero voltage turn-on bridge arm according to a total working time of the first bridge arm and a total working time of the second bridge arm.

10. The conversion circuit according to claim 8, wherein: The controller is further configured to determine the zero voltage turn-on bridge arm when the conversion circuit operates in the synchronous rectification mode this time according to the zero voltage turn-on bridge arm when the conversion circuit operates in the synchronous rectification mode last time.

11. The conversion circuit according to any one of claims 1 to 10, wherein: The controller is further configured to: When the torque is greater than or equal to a first preset value, controlling the conversion circuit to switch to the high-frequency PFC mode to operate; When the torque is less than a first preset value, the conversion circuit is controlled to switch to the synchronous rectification mode to operate.

12. The conversion circuit according to any one of claims 1 to 11, wherein: The controller is further configured to obtain the rotation speed of the motor, determine the torque according to the rotation speed difference between the rotation speed of the motor and the target rotation speed, and determine the product value between the rotation speed of the motor and the torque, wherein: When the product value is greater than or equal to a second preset value, controlling the conversion circuit to switch to the high-frequency PFC mode to operate; When the product value is less than a second preset value, the conversion circuit is controlled to switch to the synchronous rectification mode to operate.

13. Electrical equipment, including: Motor; According to any one of claims 1-12, the conversion circuit is suitable for converting an input AC power supply into a DC power supply to power the motor.

14. A method for controlling a PFC circuit in a refrigeration device, wherein: The PFC circuit includes a synchronous rectification mode and a high-frequency PFC mode, and the method includes: determining a torque of a compressor in the refrigeration device; The PFC circuit is controlled to switch between the synchronous rectification mode and the high frequency PFC mode according to the torque of the compressor.

15. The method according to claim 14, wherein: Controlling the PFC circuit to switch between the synchronous rectification mode and the high-frequency PFC mode according to the torque of the compressor includes: When the torque is greater than or equal to a first preset value, controlling the PFC circuit to switch to the high-frequency PFC mode to operate; When the torque is less than a first preset value, the PFC circuit is controlled to switch to the synchronous rectification mode to operate.

16. The method according to claim 14 or 15, wherein: Determining the torque of a compressor in the refrigeration device includes: Obtaining the rotation speed of the compressor; The torque of the compressor is determined according to a speed difference between the speed of the compressor and a target speed.

17. The method according to claim 16, wherein: Controlling the PFC circuit to switch between the synchronous rectification mode and the high-frequency PFC mode according to the torque of the compressor includes: Determining a product value between a rotational speed and a torque of the compressor; When the product value is greater than or equal to a second preset value, controlling the PFC circuit to switch to the high-frequency PFC mode to operate; When the product value is less than a second preset value, the PFC circuit is controlled to switch to the synchronous rectification mode to operate.

18. The method according to any one of claims 14 to 17, wherein: The PFC circuit includes an inductor and a bridge circuit, the bridge circuit includes a plurality of switch tubes, the plurality of switch tubes are configured to form a first bridge arm and a second bridge arm connected in parallel, one of the first bridge arm and the second bridge arm is connected to the inductor, wherein: In the case where the upper bridge switch tube and the lower bridge switch tube in the first bridge arm are turned on or off based on the polarity of the input AC power supply, and the upper bridge switch tube and the lower bridge switch tube in the second bridge arm are turned on or off based on the magnitude and polarity of the current flowing through the inductor, the PFC circuit operates in the synchronous rectification mode; or, in the case where the upper bridge switch tube and the lower bridge switch tube in the second bridge arm are turned on or off based on the polarity of the input AC power supply, and the upper bridge switch tube and the lower bridge switch tube in the first bridge arm are turned on or off based on the magnitude and polarity of the current flowing through the inductor, the PFC circuit operates in the synchronous rectification mode; When the upper bridge switch tube and the lower bridge switch tube in the bridge arm connected to the inductor are alternately turned on or off based on the set frequency, and the upper bridge switch tube and the lower bridge switch tube in the bridge arm not connected to the inductor are turned on or off based on the polarity of the input AC power supply, the PFC circuit operates in the high-frequency PFC mode.

19. The method according to claim 18, wherein: The upper bridge switch tube and the lower bridge switch tube in the first bridge arm or the second bridge arm are turned on or off based on the polarity of the input AC power supply, including: Determine the zero-crossing point of the input AC power; At the zero-crossing point, the upper bridge switch tube and the lower bridge switch tube are controlled to be turned on or off.

20. The method according to claim 16 or 17, wherein: Obtaining the rotation speed of the compressor, including: The rotation speed of the compressor is detected by a rotation speed sensor.

21. The method according to claim 16 or 17, wherein: Obtaining the rotation speed of the compressor, including: The rotor position of the compressor is observed by a flux observer to obtain the rotation speed of the compressor.

22. A computer-readable storage medium storing a control program of a PFC circuit in a refrigeration device, wherein the control program is executed by a processor to implement the control method of the PFC circuit in a refrigeration device according to any one of claims 14 to 21.

23. A controller, comprising: A memory, a processor, and a control program for a PFC circuit in a refrigeration device stored in the memory and executable on the processor, wherein when the processor executes the program, a control method for a PFC circuit in a refrigeration device according to any one of claims 14 to 21 is implemented.

24. Refrigeration equipment, including: A PFC circuit, wherein the PFC circuit includes a synchronous rectification mode and a high-frequency PFC mode; compressor; The controller is used to determine the torque of the compressor and control the PFC circuit to switch between the synchronous rectification mode and the high-frequency PFC mode according to the torque of the compressor.

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