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

Abstract

The invention discloses a conversion circuit, refrigeration equipment and a control method of a PFC (Power Factor Correction) circuit of the refrigeration equipment, and the conversion circuit comprises a bridge circuit which comprises a plurality of switching tubes which are connected into a bridge shape and are provided with an input end and an output end; an inductor; the capacitor is connected to the output end and is suitable for carrying out voltage stabilization processing on the output voltage of the bridge circuit so as to provide a direct-current power supply; and the controller is configured to obtain the torque of the motor and control the plurality of switching tubes according to the torque of the motor so as to switch the working modes of the conversion circuit, and the working modes of the conversion circuit comprise a synchronous rectification mode and a high-frequency PFC mode. According to the conversion circuit, rapid and accurate switching work between the synchronous rectification mode and the high-frequency PFC mode is achieved based on the torque of the motor, the real-time performance is high, switching is accurate, unnecessary power loss is avoided, and the purposes of high efficiency and energy saving are achieved while reliable and stable operation of the motor is guaranteed.

Description

Technical Field

[0001] The present invention relates to the technical field of household appliances, and in particular to a conversion circuit, an electrical device, a control method for a PFC (Power Factor Correction) circuit in a refrigeration device, a computer-readable storage medium, a controller and a refrigeration device. Background Art

[0002] With the development of power electronics technology, active PFC technology has been widely used with its advantages of high power factor, small harmonic current, stable output voltage, etc. At present, the BOOST type PFC is commonly used. This type of PFC has a simple structure and is easy to control, but its efficiency is relatively low. Therefore, in some occasions with high efficiency requirements, a bridgeless totem pole PFC circuit is used. This circuit reduces the number of devices in the loop and improves efficiency.

[0003] In existing electrical equipment, the PFC circuit can have the functions of synchronous rectification and high-frequency PFC at the same time. Since the high-frequency PFC mode will cause greater circuit loss, the PFC circuit needs to switch between synchronous rectification and high-frequency PFC. In related technologies, the switching between synchronous rectification and high-frequency PFC is basically done by judging the size of the input current. However, the input current is usually sampled by AD and the corresponding current value is calculated, which often has a large delay and is prone to large deviations. It is impossible to effectively control power loss and the energy saving efficiency is not high. Summary of the invention

[0004] The present invention aims to solve at least one of the technical problems in the related art to a certain extent. To this end, the first object of the present invention is to provide a conversion circuit that can quickly and accurately switch between a synchronous rectification mode and a high-frequency PFC mode based on the actual torque of the motor during the process of converting an input AC power supply into a DC power supply to power a motor load, and has higher real-time performance and accuracy, so as to achieve the purpose of high efficiency and energy saving.

[0005] The second object of the present invention is to provide an electrical device.

[0006] The third object of the present invention is to provide a control method for a PFC circuit in a refrigeration device.

[0007] A fourth object of the present invention is to provide a computer-readable storage medium.

[0008] A fifth object of the present invention is to provide a controller.

[0009] A sixth objective of the present invention is to provide a refrigeration device.

[0010] To achieve the above-mentioned purpose, the first aspect of the present invention 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 switch tubes, and the plurality of switch tubes are connected in a bridge shape and are configured 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 switch tubes according to the torque of the motor to switch the working mode of the conversion circuit, wherein the working modes of the conversion circuit include a synchronous rectification mode and a high-frequency PFC mode.

[0011] 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, rapid and accurate switching between the synchronous rectification mode and the high-frequency PFC mode is achieved. The real-time performance is high, the switching is precise, and unnecessary power loss is avoided. While ensuring the reliable and stable operation of the motor, the purpose of high efficiency and energy saving is achieved.

[0012] In addition, the conversion circuit according to the above embodiment of the present invention may also have the following additional technical features:

[0013] 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.

[0014] 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.

[0015] Optionally, in some embodiments, the switching element in the fast tube is a silicon carbide MOSFET or a gallium nitride MOSFET.

[0016] 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.

[0017] 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.

[0018] 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 turned on or off alternately based on a set frequency.

[0019] 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.

[0020] 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.

[0021] 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.

[0022] 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; when the torque is less than the first preset value, control the conversion circuit to switch to the synchronous rectification mode to operate.

[0023] Optionally, in some embodiments, the controller is further configured to obtain the speed of the motor, 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.

[0024] The second aspect of the present invention provides an electrical device, which includes: a motor; a conversion circuit according to 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.

[0025] According to the electrical equipment of the embodiment of the present invention, 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, with high real-time performance and precise switching, avoiding unnecessary power loss, and achieving the goals of high efficiency and energy saving while ensuring the reliable and stable operation of the motor.

[0026] An embodiment of the second aspect of the present invention proposes a control method for a PFC circuit in a refrigeration device, the PFC circuit including a synchronous rectification mode and a high-frequency PFC mode, the method comprising: determining the torque of a compressor in the refrigeration device; controlling the PFC circuit to switch between the synchronous rectification mode and the high-frequency PFC mode according to the torque of the compressor.

[0027] According to the control method of the PFC circuit in the refrigeration equipment of the embodiment of the present invention, 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 the reliable and stable operation of the motor, it achieves the purpose of high efficiency and energy saving.

[0028] In addition, the control method of the PFC circuit in the refrigeration equipment according to the above embodiment of the present invention may also have the following additional technical features:

[0029] According to one embodiment of the present invention, 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.

[0030] According to one embodiment of the present invention, determining the torque of the compressor in the refrigeration device includes: acquiring the rotational speed of the compressor; and determining the torque of the compressor according to a rotational speed difference between the rotational speed of the compressor and a target rotational speed.

[0031] According to another embodiment of the present invention, 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 rotational speed and the 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.

[0032] According to one embodiment of the present invention, 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, when 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 first bridge arm, the upper bridge switch tube and the lower bridge switch 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 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.

[0033] According to one embodiment of the present invention, 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.

[0034] According to an embodiment of the present invention, acquiring the rotation speed of the compressor includes: detecting the rotation speed of the compressor by a rotation speed sensor.

[0035] According to another embodiment of the present invention, obtaining the rotation speed of the compressor includes: observing the rotor position of the compressor by a flux observer to obtain the rotation speed of the compressor.

[0036] To achieve the above objectives, a fourth aspect of the present invention 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.

[0037] According to the computer-readable storage medium of the embodiment of the present invention, by executing the control method of the PFC circuit in the refrigeration equipment of the above embodiment, 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 the reliable and stable operation of the motor, the purpose of high efficiency and energy saving is achieved.

[0038] To achieve the above-mentioned purpose, a fifth aspect of the present invention proposes 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. When the processor executes the program, the control method for the PFC circuit in the refrigeration device is implemented.

[0039] According to the controller of the embodiment of the present invention, the control program of the PFC circuit in the refrigeration equipment stored in the memory is executed by the processor to implement the 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 the reliable and stable operation of the motor, the purpose of high efficiency and energy saving is achieved.

[0040] To achieve the above-mentioned purpose, the sixth aspect of the present invention proposes a refrigeration device, including: a PFC circuit, the PFC circuit including a synchronous rectification mode and a high-frequency PFC mode; a compressor; a controller, 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.

[0041] According to the refrigeration equipment of the embodiment of the present invention, 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 the reliable and stable operation of the motor, the purpose of high efficiency and energy saving is achieved.

[0042] 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

[0043] Figure 1 A hardware topology diagram of a conversion circuit according to an embodiment of the present invention;

[0044] Figure 2 A timing diagram of controlling a switch tube in a synchronous rectification mode according to an embodiment of the present invention;

[0045] Figure 3 According to one embodiment of the present invention Figure 2 A schematic diagram of the current flow direction of the positive half cycle of the AC power supply in the corresponding synchronous rectification mode;

[0046] Figure 4 According to one embodiment of the present invention Figure 2 A schematic diagram of the current flow direction of the negative half cycle of the AC power supply in the corresponding synchronous rectification mode;

[0047] Figure 5 is a timing diagram of controlling a switch tube in a synchronous rectification mode according to another embodiment of the present invention;

[0048] Figure 6 According to one embodiment of the present invention Figure 5 A schematic diagram of the current flow direction of the positive half cycle of the AC power supply in the corresponding synchronous rectification mode;

[0049] Figure 7 According to one embodiment of the present invention Figure 5 A schematic diagram of the current flow direction of the negative half cycle of the AC power supply in the corresponding synchronous rectification mode;

[0050] Figure 8 A timing diagram of controlling a switch tube in a high frequency PFC mode according to an embodiment of the present invention;

[0051] Fig. 9 According to one embodiment of the present invention Figure 8 Schematic diagram of the current flow in the positive half cycle of the AC power supply in the corresponding high-frequency PFC mode;

[0052] Fig.10 According to one embodiment of the present invention Figure 8 Schematic diagram of the current flow in the positive half cycle of the AC power supply in the corresponding high-frequency PFC mode;

[0053] Fig.11 is a flow chart of determining torque according to one embodiment of the present invention;

[0054] Fig.12 is a block diagram of an electrical device according to an embodiment of the present invention;

[0055] Fig.13is a flow chart of a method for controlling a PFC circuit in a refrigeration device according to an embodiment of the present invention;

[0056] Fig.14 is a block diagram of a controller according to an embodiment of the present invention;

[0057] Fig.15 FIG. 4 is a block diagram of a refrigeration device according to an embodiment of the present invention. DETAILED DESCRIPTION

[0058] 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.

[0059] 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 invention with reference to the accompanying drawings.

[0060] Figure 1 FIG. 4 is a hardware topology diagram of a conversion circuit according to an embodiment of the present invention.

[0061] like Figure 1 As shown, the conversion circuit 300 of the embodiment of the present invention is suitable for converting the input AC power supply into a DC power supply to power the motor. The conversion circuit 300 includes: a bridge circuit 310, an inductor L1, a capacitor C1 and a controller 320.

[0062] The bridge circuit 310 includes a plurality of switch tubes connected to form a bridge shape and having an input end and an output end.

[0063] It should be noted that the circuit in which multiple switch 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.

[0064] The inductor L1 is connected between the alternating current power source AC and the input end of the bridge circuit 310 . The inductor L1 can store the electric power supplied from the alternating current power source AC as energy and release the energy to increase the voltage and improve the power factor.

[0065] 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.

[0066] The controller 320 is configured to obtain the torque of the motor and control multiple switch 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.

[0067] Specifically, the electric energy provided by the AC power source AC is input into the bridge circuit 310 through the inductor L1 for conversion, and the capacitor C1 can smooth the voltage output from the bridge circuit 310 to become a DC voltage to power the motor. During the operation of the motor, the controller 320 can obtain the torque of the motor in real time, and control multiple switch tubes according to the torque of the motor to control whether the conversion circuit 300 is operated in a synchronous rectification mode or a high-frequency PFC mode. For example, when the motor is started, the torque of the motor is large, and the controller 320 can control the conversion circuit 300 to operate directly in a high-frequency PFC mode; when the motor is in a stable operation stage, the torque of the motor is small, and the controller 320 can control the conversion circuit 300 to operate in a synchronous rectification mode. It should be understood that when the conversion circuit 300 operates in a high-frequency PFC mode, since the switch tube is in a high-frequency operation mode, it will cause a large switching loss; when the conversion circuit 300 operates in a synchronous rectification mode, the switch tube is in a low-frequency operation mode, so the switching loss is small.

[0068] Therefore, the conversion circuit 300 of the embodiment of the present invention, in the process of converting the input AC power supply AC into a 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 goals of high efficiency and energy saving while ensuring reliable and stable operation of the motor.

[0069] According to one embodiment of the present invention, Figure 1 As shown, multiple switch tubes are configured to form a first bridge arm 311 and a second bridge arm 312 connected in parallel, the midpoint of the first bridge arm 311 and the midpoint of the second bridge arm 312 serve as input ends, and both ends of the first bridge arm 311 or the second bridge arm 312 serve as output ends, and the midpoint of the first bridge arm 311 is connected to the AC power supply AC through the inductor L1.

[0070] Specifically, if Figure 1As shown, the first bridge arm 311 includes an upper bridge switch tube Q1 and a lower bridge switch tube Q2 connected in series, and the second bridge arm 312 includes an upper bridge switch tube Q3 and a lower bridge switch tube Q4 connected in series. The upper bridge switch tube Q1 and the lower bridge switch tube Q2 in the first bridge arm 311, and the upper bridge switch tube Q3 and the lower bridge switch tube Q4 in the second bridge arm 312 form a bridge circuit 310, and the upper bridge switch tube Q1 and the lower bridge switch tube Q2 in the first bridge arm 311, and the upper bridge switch tube Q3 and the lower bridge switch tube Q4 in the second bridge arm 312 all have parasitic diodes, which can be used for freewheeling. One end of the inductor L1 is connected to one end of the AC power supply AC, and the other end of the inductor L1 is connected to the connection point of the upper bridge switch tube Q1 and the lower bridge switch tube Q2 in the first bridge arm 311. The positive electrode of the capacitor C1 is connected to the drain of the upper bridge switch tube Q1 in the first bridge arm 311 and the upper bridge switch tube Q3 in the second bridge arm 312, and the negative electrode is connected to the source of the lower bridge switch tube Q2 in the first bridge arm 311 and the lower bridge switch tube Q4 in the second bridge arm 312. The controller 320 is connected to the control end of each switch tube respectively. The controller 320 can also collect the voltage V of the input AC power supply AC AC , the current I flowing through the inductor L1 AC , and collect the bus voltage V DC .

[0071] According to an embodiment of the present invention, the upper bridge switch tube Q1 and the lower bridge switch tube Q2 in the first bridge arm 311 are configured as fast tubes, and the upper bridge switch tube Q3 and the lower bridge switch tube Q4 in the second bridge arm 312 are configured as slow tubes. Therefore, the reverse recovery time of the upper bridge switch tube Q1 and the lower bridge switch tube Q2 in the first bridge arm 311 is faster than the reverse recovery time of the upper bridge switch tube Q3 and the lower bridge switch tube Q4 in the second bridge arm 312, which can meet the requirement that in the high-frequency PFC mode, the controller 320 controls the upper bridge switch tube Q1 and the lower bridge switch tube Q2 in the first bridge arm 311 to perform high-frequency switching or shutting.

[0072] Optionally, in some embodiments, the switching element in the fast tube is a silicon carbide MOSFET or a gallium nitride MOSFET.

[0073] According to one embodiment of the present invention, 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 source 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.

[0074] Specifically, when the conversion circuit 300 operates in the 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 source 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, wherein the timing of controlling the switch tubes in the synchronous rectification mode is as follows: Figure 2 As shown, the voltage of the AC power supply is V AC , the current of inductor L1 is I AC Please refer to Figure 1 and Figure 2 In 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, and 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 I AC When crossing zero, the controller 320 controls the lower bridge switch Q4 in the second bridge arm 312 to turn on, and 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, and the current I AC The flow direction is Figure 3 As shown by the dotted line in , the parasitic diode of the lower bridge switch Q4 in the second bridge arm 312 can be prevented from being burned out, and the turn-on loss can be reduced. Similarly, in 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, and 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 I AC When the current I AC The flow direction is Figure 4 As shown by the dotted line in FIG, the AC power source AC, the upper bridge switch tube Q3 in the second bridge arm 312, the capacitor C1, the lower bridge switch tube Q2 in the first bridge arm 311, the inductor L1 and the AC power source AC form a loop, and a current I flows through AC , thereby preventing the parasitic diode of the upper bridge switch tube Q3 in the second bridge arm 312 from being burned out and reducing the turn-on loss.

[0075] According to another embodiment of the present invention, when the conversion circuit 300 operates in 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 AC 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.

[0076] Specifically, when the conversion circuit 300 operates in the 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 turn on or off according to the polarity of the AC power source AC, and 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 magnitude and polarity of the current flowing through the inductor L1, wherein the timing of controlling the switch tubes in the synchronous rectification mode is as follows: Figure 5 As shown, the voltage of the AC power supply is V AC , the current of inductor L1 is I AC Please refer to Figure 1 and Figure 5 In 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, and 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 I AC When crossing zero, the controller 320 controls the lower bridge switch Q2 in the first bridge arm 311 to turn on, and 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, and the current I AC The flow direction is Figure 6 As shown by the dotted line in the figure, the parasitic diode of the lower bridge switch Q2 in the first bridge arm 311 can be prevented from being burned out and the turn-on loss can be reduced. Similarly, in 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 I AC When the current I AC The flow direction is Figure 7As shown by the dotted line in FIG, the AC power source AC, the lower bridge switch tube Q4 in the second bridge arm 312, the capacitor C1, the upper bridge switch tube Q1 in the first bridge arm 311, the inductor L1 and the AC power source AC form a loop, and a current I flows through AC , thereby preventing the parasitic diode of the upper bridge switch tube Q1 in the first bridge arm 311 from being burned out and reducing the turn-on loss.

[0077] According to one embodiment of the present invention, when the conversion circuit 300 operates in a high-frequency PFC mode, the upper bridge switch tube Q3 and the lower bridge switch tube Q4 in the second bridge arm 312 are turned on or off based on the polarity of the AC power supply AC, and the upper bridge switch tube Q1 and the lower bridge switch tube Q2 in the first bridge arm 311 are alternately turned on or off based on a set frequency.

[0078] 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 source 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, wherein the timing of controlling the switch tubes in the high-frequency PFC mode is as follows: Figure 8 Please refer to Figure 1 and Figure 8 In the positive 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, 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 source 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 source AC form a loop, and the current I AC The flow direction is Fig. 9 As shown by the dotted line in , the AC power source AC charges the inductor L1; then the upper bridge switch tube Q1 in the first bridge arm 311 is controlled to be turned on and the lower bridge switch tube Q2 is turned off, and the AC power source AC, the inductor L1, the upper bridge switch tube Q1 in the first bridge arm 311, the capacitor C1, the lower bridge switch tube Q4 in the second bridge arm 312, and the AC power source AC form a loop, and the current I AC The flow direction is Fig.10 As shown by the dotted line in , the electricity 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 tube Q1 and the lower bridge switch tube Q2 in the first bridge arm 311 to turn on or off alternately based on the set frequency.

[0079] In the negative 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, 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 source 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 source AC form a loop, and the AC power source AC has an effect on the inductor L1. The controller 320 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 in the figure, 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 electricity 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 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 turn on or off alternately based on the set frequency.

[0080] According to one embodiment of the present invention, 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.

[0081] 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 be turned on or off at the zero-crossing point.

[0082] According to one embodiment of the present invention, 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 AC power supply AC, the first bridge arm 311 is used as a zero-voltage turned-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 AC power supply AC, the second bridge arm 312 is used as a zero-voltage turned-on bridge arm.

[0083] That is, when the conversion circuit 300 operates in synchronous rectification mode, when the upper bridge switch and the lower bridge switch in one bridge arm are turned on or off based on the polarity of the AC power source AC, the bridge arm is a zero voltage turned-on bridge arm.

[0084] According to one embodiment of the present invention, 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 working time of the first bridge arm 311 and the total working time of the second bridge arm 312 .

[0085] Specifically, by Figure 2 and Figure 5 It can be seen that when the conversion circuit 300 works in the synchronous rectification mode, the working time of the zero voltage opening bridge arm is longer than the working time of the non-zero voltage opening bridge arm. The controller 320 can count the total working time of the two bridge arms, and compare the total working time of the two bridge arms, and control the bridge arm with the longer total working time as the zero voltage opening bridge arm. In this way, the working time of the two bridge arms can be balanced, so that the working time of the switch tubes in the bridge arms tends to be consistent, and the service life of the conversion circuit 300 is improved.

[0086] According to another embodiment of the present invention, the controller 320 is further configured to determine the zero voltage turn-on bridge arm when operating in the synchronous rectification mode this time according to the zero voltage turn-on bridge arm when the conversion circuit 300 last operated in the synchronous rectification mode.

[0087] According to an embodiment of the present invention, the controller 320 is further configured to control the conversion circuit 300 to switch to the high-frequency PFC mode for operation when the torque is greater than or equal to the first preset value; and to control the conversion circuit 300 to switch to the synchronous rectification mode for operation when the torque is less than the first preset value. The first preset value can be calibrated according to actual conditions and is not limited here.

[0088] 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.

[0089] According to another embodiment of the present invention, the controller 320 is further configured to obtain the speed of the motor, determine the torque according to 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 the second preset value, the control conversion circuit 300 is switched to the high-frequency PFC mode for operation; when the product value is less than the second preset value, the control conversion circuit 300 is switched to the synchronous rectification mode for operation. The second preset value can be calibrated according to actual conditions, and is not limited here.

[0090] Specifically, if Fig.11As shown, 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 and torque of the compressor, 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.

[0091] In some embodiments of the present invention, the Te value can also be obtained by 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 electromotive force, Ld is the motor D-axis inductance value, Lq is the motor Q-axis inductance value, Id is the motor D-axis control current value, and Iq is the motor Q-axis control current value. Among them, the controller can obtain the number of motor pole pairs P, the motor back electromotive force Ke, the motor D-axis inductance value Ld, the motor Q-axis inductance value Lq, the motor D-axis control current value Id, and the motor Q-axis control current value Iq, and substitute them into the above formula for calculation to obtain the torque of the motor.

[0092] In summary, according to the conversion circuit of the embodiment of the present invention, in the process of converting the input AC power supply into a 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. The real-time performance is high, the switching is precise, and unnecessary power loss is avoided. While ensuring the reliable and stable operation of the motor, the purpose of high efficiency and energy saving is achieved.

[0093] Corresponding to the above embodiment, the present invention also proposes an electrical device.

[0094] Fig.12 FIG. 4 is a block diagram of an electrical device according to an embodiment of the present invention.

[0095] like Fig.12 As shown, the electrical device 400 of the embodiment of the present invention includes: a motor 410; and a conversion circuit 300 described in the above embodiment, the conversion circuit is suitable for converting the input AC power into a DC power to power the motor.

[0096] According to the electrical equipment of the embodiment of the present invention, 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, with high real-time performance and precise switching, avoiding unnecessary power loss, and achieving the goals of high efficiency and energy saving while ensuring the reliable and stable operation of the motor.

[0097] Corresponding to the above embodiment, the present invention further proposes a control method for a PFC circuit in a refrigeration device.

[0098] Fig.13 The figure is a flow chart of a method for controlling a PFC circuit in a refrigeration device according to an embodiment of the present invention.

[0099] In some embodiments of the present invention, the refrigeration device can adjust the power factor of the refrigeration device through the PFC circuit and can increase the DC bus voltage, which mainly provides power to the compressor and the fan motor. The PFC circuit includes a synchronous rectification mode and a high-frequency PFC mode.

[0100] When the refrigeration equipment is started, the input power is large, and the high-frequency PFC mode is directly turned on. In some states where the input power is not large, the high-frequency PFC mode does not need to be turned on. Switching the high-frequency PFC mode to the synchronous rectification mode can meet the requirements for adjusting the power factor of the refrigeration equipment. Among them, when the PFC circuit is running in the high-frequency PFC mode, since the control tube is in the high-frequency operation mode, it will cause a large switching loss; when the PFC circuit is running in the synchronous rectification mode, the control tube is in the low-frequency operation mode, so the switching loss is small.

[0101] like Fig.13 As shown, the control method of the PFC circuit in the refrigeration equipment according to the embodiment of the present invention may include the following steps:

[0102] S1, determine the torque of the compressor in the refrigeration equipment.

[0103] 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.

[0104] The control method of the PFC circuit in the refrigeration equipment of the embodiment of the present invention 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. The method 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.

[0105] According to an embodiment of the present invention, 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 work; when the torque is less than the first preset value, controlling the PFC circuit to switch to the synchronous rectification mode to work. The first preset value can be set according to specific parameters of the refrigeration equipment, and is not limited here.

[0106] According to one embodiment of the present invention, determining the torque of a compressor in a refrigeration device includes: acquiring a rotation speed of the compressor; and determining the torque of the compressor according to a rotation speed difference between the rotation speed of the compressor and a target rotation speed.

[0107] According to an embodiment of the present invention, obtaining the rotation speed of the compressor includes: obtaining the rotation speed of the compressor through a rotation speed sensor.

[0108] 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. The rotation speed sensor can be a Hall sensor.

[0109] According to another embodiment of the present invention, obtaining the rotation speed of the compressor includes: observing the rotor position of the compressor through a flux observer to obtain the rotation speed of the compressor.

[0110] Specifically, the stator flux angle and flux size can be identified through the flux observer, and the rotor position can be obtained, thereby inferring the motor rotor speed of the compressor, thereby obtaining the speed of the compressor. Furthermore, after obtaining the speed of the compressor, the controller can make a difference between the speed and the target speed, and then perform PI control on the speed difference of the compressor to obtain the torque of the compressor. The controller compares the torque with the first preset value. When the torque is greater than or equal to the first preset value, the controller 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 controls the PFC circuit to switch to the synchronous rectification mode for operation.

[0111] In some embodiments of the present invention, the Te value can also be obtained by 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 electromotive force, Ld is the motor D-axis inductance value, Lq is the motor Q-axis inductance value, Id is the motor D-axis control current value, and Iq is the motor Q-axis control current value. Among them, the controller can obtain the number of pole pairs P, back electromotive force Ke, D-axis inductance value Ld, Q-axis inductance value Lq, D-axis control current value Id, and Q-axis control current value Iq of the compressor, and substitute them into the above formula for calculation, and the torque of the compressor can be obtained.

[0112] According to another embodiment of the present invention, 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 the product value between the speed and the 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 work; when the product value is less than the second preset value, controlling the PFC circuit to switch to the synchronous rectification mode to work. The second preset value can be set according to the specific parameters of the refrigeration equipment, which is not limited here.

[0113] 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 the 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.

[0114] According to one embodiment of the present invention, a 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, when 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 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.

[0115] According to one embodiment of the present invention, 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.

[0116] 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 invention, 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 invention, and will not be repeated here.

[0117] In summary, according to the control method of the PFC circuit in the refrigeration equipment according to the embodiment of the present invention, 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 the reliable and stable operation of the motor, it achieves the purpose of high efficiency and energy saving.

[0118] Corresponding to the above embodiment, the present invention also proposes a computer-readable storage medium.

[0119] The computer-readable storage medium of the embodiment of the present invention stores a control program of the PFC circuit in the refrigeration device, and the program implements the control method of the PFC circuit in the refrigeration device when executed by the processor.

[0120] According to the computer-readable storage medium of the embodiment of the present invention, by executing the control method of the PFC circuit in the refrigeration equipment of the above embodiment, 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 the reliable and stable operation of the motor, the purpose of high efficiency and energy saving is achieved.

[0121] Corresponding to the above embodiment, the present invention also proposes a controller.

[0122] Fig.14 is a block diagram of a controller according to an embodiment of the present invention.

[0123] like Fig.14 As shown, the controller 200 of the embodiment of the present invention includes: a memory 210, a processor 220, and a control program for the PFC circuit in the refrigeration device 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 device described above is implemented.

[0124] According to the controller of the embodiment of the present invention, the control program of the PFC circuit in the refrigeration equipment stored in the memory is executed by the processor to implement the 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 the reliable and stable operation of the motor, the purpose of high efficiency and energy saving is achieved.

[0125] Corresponding to the above embodiment, the present invention also proposes a refrigeration device.

[0126] Fig.15 FIG. 4 is a block diagram of a refrigeration device according to an embodiment of the present invention.

[0127] like Fig.15 As shown, the refrigeration device 100 according to the embodiment of the present invention may include: a PFC circuit 110 , a compressor 120 and a controller 130 .

[0128] The PFC circuit 110 includes a synchronous rectification mode and a high-frequency PFC mode. The controller 130 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.

[0129] According to one embodiment of the present invention, 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 control the PFC circuit to switch to the high-frequency PFC mode for operation when the torque is greater than or equal to a first preset value; and to control the PFC circuit to switch to the synchronous rectification mode for operation when the torque is less than the first preset value.

[0130] According to an embodiment of the present invention, the controller 130 determines the torque of the compressor in the refrigeration equipment, specifically, to obtain the rotation speed of the compressor; and determines the torque of the compressor according to the rotation speed difference between the rotation speed of the compressor and the target rotation speed.

[0131] According to another embodiment of the present invention, 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.

[0132] According to one embodiment of the present invention, a 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, when 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 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.

[0133] According to one embodiment of the present invention, 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.

[0134] According to an embodiment of the present invention, the controller 130 acquires the rotation speed of the compressor, specifically, detects the rotation speed of the compressor through a rotation speed sensor.

[0135] According to another embodiment of the present invention, the controller 130 obtains the speed of the compressor, specifically, observes the rotor position of the compressor through a flux observer to obtain the speed of the compressor. It should be noted that for details not disclosed in the refrigeration device of the embodiment of the present invention, please refer to the details disclosed in the control method of the PFC circuit in the refrigeration device of the embodiment of the present invention, and the details will not be repeated here.

[0136] According to the refrigeration equipment of the embodiment of the present invention, 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 the reliable and stable operation of the motor, the purpose of high efficiency and energy saving is achieved.

[0137] 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.

[0138] 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.

[0139] 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.

[0140] 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.

[0141] 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.

[0142] 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 conversion circuit, characterized in that: Suitable for converting input AC power into DC power to power the motor, the conversion circuit includes: 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 and adapted to stabilize 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, characterized in that: 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, characterized in that: 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, characterized in that: The switch element in the fast tube is a silicon carbide MOSFET or a gallium nitride MOSFET.

5. The conversion circuit according to claim 2, characterized in that: 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 claim 2, characterized in that: 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 claim 3, characterized in that: 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 claim 2, characterized in that: 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, characterized in that: 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, characterized in that: 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, characterized in that: 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 10, characterized in that: 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. An electrical device, characterized in that: include: 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, characterized in that: 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, characterized in that 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, characterized in that 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, characterized in that 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, characterized in that: 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, characterized in that 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, characterized in that 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, characterized in that 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, characterized in that: A control program for a PFC circuit in a refrigeration device is stored thereon, and when the program is executed by a processor, a control method for a PFC circuit in a refrigeration device according to any one of claims 14-21 is implemented.

23. A controller, characterized in that: include: 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. A refrigeration device, characterized in that: include: 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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