Converter circuit, refrigeration equipment, and control method for its PFC circuit

Abstract

A control method for a converter circuit (300), a refrigeration system (100), and its PFC circuit (110), wherein the converter circuit (300) includes a plurality of switch transistors, the plurality of switch transistors are connected in a bridge configuration, and a bridge circuit (310) is formed with an input terminal and an output terminal; an inductor (L1); a capacitor (C1) connected to the output terminal and suitable for stabilizing the output voltage of the bridge circuit (310) and providing a DC power supply; and a controller (320) configured to acquire the torque of a motor (410), control the plurality of switch transistors based on the torque of the motor (410), and switch the operating mode of the converter circuit (300), the operating mode of the converter circuit (300) includes a synchronous rectification mode and a high-frequency PFC mode.

Description

Technical Field

[0001] The present disclosure claims the priority of the Chinese patent application filed with the China National Intellectual Property Administration on August 31, 2023, with the application number 202311124828.3 and the title of invention "Converter circuit, refrigeration equipment and control method for PFC circuit thereof", the entire content of which is incorporated into the present disclosure by reference.

[0002] The present disclosure relates to the field of household electrical appliance technology, and in particular to a converter circuit, a refrigeration equipment, and a control method for a PFC circuit thereof.

Background Art

[0003] With the development of power electronic technology, active PFC (Power Factor Correction) technology has been widely applied due to its advantages of high power factor, low harmonic current, and stable output voltage. Currently, BOOST-type PFC is commonly used. Such a PFC has a simple structure and is easy to control, but has low efficiency. Therefore, when high requirements are imposed on efficiency, a bridgeless totem-pole PFC circuit is employed. Such a circuit can reduce the number of components on the circuit and improve efficiency.

[0004] In conventional electrical devices, the PFC circuit has the functions of synchronous rectification and high-frequency PFC at the same time. In the high-frequency PFC mode, large loss occurs in the circuit, so the PFC circuit needs to be switched between synchronous rectification and high-frequency PFC. In the related art, switching between synchronous rectification and high-frequency PFC is basically performed by judging the magnitude of the input current. However, since the input current usually adopts a method of calculating the corresponding current value by AD sampling, large delay tends to occur, errors tend to be large, power loss cannot be effectively suppressed, and the energy saving efficiency is not high.

Summary of Invention

Problem to be Solved by the Invention

[0005] This disclosure aims to solve, at least to a certain extent, one of the technical problems in related technologies. Therefore, the first object of this disclosure is to provide a converter circuit that can quickly and accurately switch between synchronous rectification mode and high-frequency PFC mode based on the actual torque of the motor in the process of converting an input AC power supply to a DC power supply and supplying power to the motor load, thereby achieving higher real-time performance and accuracy, and realizing the objective of efficient energy saving. [Means for solving the problem]

[0006] A second object of this disclosure is to provide electrical equipment.

[0007] A third object of this disclosure is to provide a method for controlling a PFC circuit in a refrigeration system.

[0008] A fourth object of this disclosure is to provide a computer-readable storage medium.

[0009] The fifth object of this disclosure is to provide a controller.

[0010] The sixth object of this disclosure is to provide refrigeration equipment.

[0011] To achieve the above objective, an embodiment of a first aspect of the present disclosure provides a converter circuit suitable for converting an input AC power supply into a DC power supply and supplying power to a motor, the converter circuit comprising a plurality of switch transistors, the plurality of switch transistors connected in a bridge configuration and comprising an input terminal and an output terminal, an inductor connected between the AC power supply and the input terminal, a capacitor connected to the output terminal and suitable for stabilizing the output voltage of the bridge circuit and providing the DC power supply, and a controller configured to acquire the torque of the motor, control the plurality of switch transistors based on the torque of the motor, and switch the operating modes of the converter circuit, including a synchronous rectification mode and a high-frequency PFC mode.

[0012] The converter circuit according to the embodiment of this disclosure converts the input AC power supply to a DC power supply and supplies power to the motor. In the process, it acquires the actual torque of the motor, thereby achieving rapid and accurate switching between synchronous rectification mode and high-frequency PFC mode based on the motor torque. This results in high real-time performance, accurate switching, avoidance of unnecessary power loss, and high efficiency and energy saving while ensuring motor reliability and stable operation.

[0013] Furthermore, the converter circuit according to the above embodiment of this disclosure may have the following additional technical features.

[0014] In some embodiments, the plurality of switch transistors constitute a first bridge arm and a second bridge arm connected in parallel, with the midpoint of the first bridge arm and the midpoint of the second bridge arm serving as the input terminals, and both ends of the first bridge arm or the second bridge arm serving as the output terminals, and the midpoint of the first bridge arm connected to the AC power supply via the inductor.

[0015] Furthermore, the upper and lower bridge switch transistors in the first bridge arm are configured as high-speed transistors, while the upper and lower bridge switch transistors in the second bridge arm are configured as low-speed transistors.

[0016] In some embodiments, the switching element in the high-speed transistor is optionally a silicon carbide MOSFET or a gallium nitride MOSFET.

[0017] In some embodiments, as selectable, when the converter circuit operates in the synchronous rectification mode, the upper and lower bridge switch transistors in the first bridge arm conduct or disconnect based on the polarity of the AC power supply, and the upper and lower bridge switch transistors in the second bridge arm conduct or disconnect based on the magnitude and polarity of the current flowing through the inductor.

[0018] In some embodiments, as selectable, when the converter circuit operates in the synchronous rectification mode, the upper and lower bridge switch transistors in the second bridge arm conduct or disconnect based on the polarity of the AC power supply, and the upper and lower bridge switch transistors in the first bridge arm conduct or disconnect based on the magnitude and polarity of the current flowing through the inductor.

[0019] In some embodiments, as selectable, when the converter circuit operates in the high-frequency PFC mode, the upper and lower bridge switch transistors in the second bridge arm conduct or disconnect based on the polarity of the AC power supply, and the upper and lower bridge switch transistors in the first bridge arm conduct or disconnect alternately based on a predetermined frequency.

[0020] In some embodiments, the converter circuit operates in the synchronous rectification mode, and the first bridge arm becomes a zero-voltage conducting bridge arm when the upper and lower bridge switch transistors in the first bridge arm conduct or disconnect based on the polarity of the AC power supply, and the second bridge arm becomes a zero-voltage conducting bridge arm when the upper and lower bridge switch transistors in the second bridge arm conduct or disconnect based on the polarity of the AC power supply.

[0021] In some embodiments, the controller is further configured to determine which of the first and second bridge arms is the zero-voltage conducting bridge arm based on the total operating time of the first and second bridge arms.

[0022] In some embodiments, the controller is further configured to determine the zero-voltage conduction bridge arm for the current operation in the synchronous rectification mode based on the zero-voltage conduction bridge arm from the previous operation of the converter circuit in the synchronous rectification mode.

[0023] In some embodiments, the controller is optionally configured to further control the converter circuit to switch to the high-frequency PFC mode when the torque is greater than or equal to a first predetermined value, and to control the converter circuit to switch to the synchronous rectification mode when the torque is less than the first predetermined value.

[0024] In some embodiments, the controller is configured to further acquire the rotational speed of the motor, determine the torque based on the rotational speed difference between the motor's rotational speed and a target rotational speed, determine the product of the motor's rotational speed and the torque, control the converter circuit to switch to the high-frequency PFC mode if the product is greater than or equal to a second predetermined value, and control the converter circuit to switch to the synchronous rectification mode if the product is less than the second predetermined value.

[0025] An embodiment of a second aspect of the present disclosure proposes an electrical device comprising a motor and a converter circuit as described in the above embodiment, which is suitable for converting an input AC power source into a DC power source and supplying power to the motor.

[0026] An electrical device according to an embodiment of the present disclosure is based on the converter circuit described in the above embodiments, converts an input alternating current power supply into a direct current power supply, and in the process of supplying power to a motor, can implement a rapid and accurate switching operation between a synchronous rectification mode and a high-frequency PFC mode based on the torque of the motor, which has high real-time performance and accurate switching, avoids unnecessary power loss, and achieves the objectives of high efficiency and energy saving while ensuring the reliability and stable operation of the motor.

[0027] An embodiment according to the second aspect of the present disclosure proposes a control method for a PFC circuit in refrigeration equipment, wherein the PFC circuit includes a synchronous rectification mode and a high-frequency PFC mode, and the method comprises the steps of: determining the torque of a compressor in the refrigeration equipment; and controlling the PFC circuit to switch between the synchronous rectification mode and the high-frequency PFC mode based on the torque of the compressor.

[0028] The control method for a PFC circuit in refrigeration equipment according to an 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, since the switching point between the synchronous rectification mode and the high-frequency PFC mode of the PFC circuit is determined by the torque of the compressor, the method has higher real-time performance and accuracy, ensures accurate switching, can avoid unnecessary power loss, and achieves the objectives of high efficiency and energy saving while ensuring the reliability and stable operation of the motor.

[0029] In addition, the control method for a PFC circuit in refrigeration equipment according to the above embodiments of the present disclosure may have the following additional technical features.

[0030] According to an embodiment of the present disclosure, the step of controlling the PFC circuit to switch between the synchronous rectification mode and the high-frequency PFC mode based on the torque of the compressor comprises: when the torque is greater than or equal to a first predetermined value, controlling the PFC circuit to switch to the high-frequency PFC mode for operation; and when the torque is less than the first predetermined value, controlling the PFC circuit to switch to the synchronous rectification mode for operation.

[0031] According to one embodiment of the present disclosure, the step of determining the torque of a compressor in the refrigeration equipment includes the steps of obtaining the rotational speed of the compressor and determining the torque of the compressor based on the rotational speed difference between the rotational speed of the compressor and a target rotational speed.

[0032] According to other embodiments of the present disclosure, the step of controlling a PFC circuit to switch between a synchronous rectification mode and a high-frequency PFC mode based on the torque of a compressor includes the steps of determining the product of the compressor speed and torque, controlling the PFC circuit to switch to and operate in high-frequency PFC mode if the product is greater than or equal to a second predetermined value, and controlling the PFC circuit to switch to and operate in synchronous rectification mode if the product is less than the second predetermined value.

[0033] According to one embodiment of the present disclosure, the PFC circuit comprises an inductor and a bridge circuit, the bridge circuit comprises a plurality of switch transistors, the plurality of switch transistors constitute 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, the upper bridge switch transistor and the lower bridge switch transistor in the first bridge arm conduct or disconnect based on the polarity of the input AC power supply, and the upper bridge switch transistor and the lower bridge switch transistor in the second bridge arm conduct or disconnect based on the magnitude and polarity of the current flowing through the inductor, the PFC circuit operates in the synchronous rectification mode, or the second bridge arm When the upper and lower bridge switch transistors are connected or disconnected based on the polarity of the input AC power supply, and the upper and lower bridge switch transistors in the first bridge arm are connected or disconnected 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 and lower bridge switch transistors in the bridge arm connected to the inductor are connected or disconnected alternately based on a predetermined frequency, and the upper and lower bridge switch transistors in the bridge arm not connected to the inductor are connected or disconnected based on the polarity of the input AC power supply, the PFC circuit operates in the high-frequency PFC mode.

[0034] According to one embodiment of the present disclosure, the upper bridge switch transistor and the lower bridge switch transistor in the first bridge arm or the second bridge arm are connected or disconnected based on the polarity of the input AC power supply, which includes the steps of determining the zero-crossing point of the input AC power supply and controlling the connection or disconnection of the upper bridge switch transistor and the lower bridge switch transistor at the zero-crossing point.

[0035] According to one embodiment of the present disclosure, the step of obtaining the rotational speed of the compressor includes the step of detecting the rotational speed of the compressor using a rotational speed sensor.

[0036] According to other embodiments of the present disclosure, the step of obtaining the rotational speed of the compressor includes observing the rotor position of the compressor using a magnetic flux observer and obtaining the rotational speed of the compressor.

[0037] To achieve the above objective, an embodiment of a fourth aspect of this disclosure proposes a computer-readable storage medium on which a control program for a PFC circuit in a refrigeration system is stored, and when the program is executed by a processor, the control method for a PFC circuit in a refrigeration system described above is realized.

[0038] The computer-readable storage medium according to the embodiments of this disclosure can be controlled to switch between synchronous rectification mode and high-frequency PFC mode by determining the torque of the compressor in the refrigeration equipment by performing the control method for the PFC circuit in the above embodiment. In this way, the switching point between the synchronous rectification mode and high-frequency PFC mode of the PFC circuit is determined by the torque of the compressor, resulting in higher real-time performance and accuracy, precise switching, avoidance of unnecessary power loss, and achieving high efficiency and energy saving while ensuring motor reliability and stable operation.

[0039] To achieve the above objective, an embodiment of a fifth aspect of this disclosure proposes a controller comprising a memory, a processor, and a control program for a PFC circuit in a refrigeration system that is stored in the memory and operable by the processor, and when the processor executes the program, a method for controlling the PFC circuit in the refrigeration system is realized.

[0040] The controller according to the embodiment of this disclosure realizes the control method for the PFC circuit in the refrigeration equipment by having the processor execute a control program for the PFC circuit in the refrigeration equipment stored in memory. This allows the PFC circuit to be controlled to switch between synchronous rectification mode and high-frequency PFC mode by determining the torque of the compressor in the refrigeration equipment. In this way, since the switching point between the synchronous rectification mode and high-frequency PFC mode of the PFC circuit is determined by the torque of the compressor, it has higher real-time performance and accuracy, the switching is precise, unnecessary power loss can be avoided, and the objectives of high efficiency and energy saving can be achieved while ensuring the reliability and stable operation of the motor.

[0041] To achieve the above objectives, an embodiment of a sixth aspect of the present disclosure proposes a refrigeration system comprising: a 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 based on the torque of the compressor.

[0042] The refrigeration equipment according to the embodiments of this disclosure controls the PFC circuit to switch between synchronous rectification mode and high-frequency PFC mode based on the compressor torque. Thus, because the switching point between synchronous rectification mode and high-frequency PFC mode of the PFC circuit is determined by the compressor torque, it has higher real-time performance and accuracy, the switching is precise, unnecessary power loss can be avoided, and high efficiency and energy saving objectives can be achieved while ensuring motor reliability and stable operation.

[0043] Additional aspects and benefits of this disclosure are partially shown in the following description, partially revealed in the following description, or can be understood through the practice of this disclosure. [Brief explanation of the drawing]

[0044] [Figure 1] This is a hardware topology diagram of a converter circuit according to an embodiment of the present disclosure. [Figure 2] This is a time-series diagram showing the control of a switch transistor in synchronous rectification mode according to one embodiment of the present disclosure. [Figure 3] This is a schematic diagram showing the current flow of an AC power supply during the positive half-cycle in a synchronous rectification mode corresponding to Figure 2 in one embodiment of the present disclosure. [Figure 4] This is a schematic diagram showing the current flow during the negative half-cycle of an AC power supply in a synchronous rectification mode corresponding to Figure 2 according to one embodiment of the present disclosure. [Figure 5] This is a time-series diagram showing the control of a switch transistor in synchronous rectification mode according to another embodiment of the present disclosure. [Figure 6] This is a schematic diagram showing the current flow of an AC power supply during the positive half-cycle in a synchronous rectification mode corresponding to Figure 5 in one embodiment of the present disclosure. [Figure 7] This is a schematic diagram showing the current flow during the negative half-cycle of an AC power supply in a synchronous rectification mode corresponding to Figure 5 in one embodiment of the present disclosure. [Figure 8] This is a time-series diagram showing the control of a switch transistor in high-frequency PFC mode according to one embodiment of the present disclosure. [Figure 9] A schematic diagram showing the current flow of an AC power supply during the positive half-cycle in the high-frequency PFC mode corresponding to Figure 8 in one embodiment of the present disclosure. [Figure 10] A schematic diagram showing the current flow of an AC power supply during the positive half-cycle in the high-frequency PFC mode corresponding to Figure 8 in one embodiment of the present disclosure. [Figure 11] This is a flowchart for determining torque according to one embodiment of the present disclosure. [Figure 12] This is a schematic block diagram of an electrical device according to an embodiment of the present disclosure. [Figure 13] This is a flowchart showing a method for controlling a PFC circuit in a refrigeration system according to an embodiment of the present disclosure. [Figure 14] This is a schematic block diagram of a controller according to an embodiment of the present disclosure. [Figure 15] This is a schematic block diagram of a refrigeration system according to an embodiment of the present disclosure. [Modes for carrying out the invention]

[0045] The embodiments of this disclosure will be described in detail below. Examples relating to the embodiments are shown in the drawings, and the same or similar reference numerals consistently indicate the same or similar elements or elements having the same or similar function. The embodiments described below with reference to the drawings are illustrative and intended to illustrate the disclosure, and shall not be construed as limiting the disclosure.

[0046] Hereinafter, with reference to the drawings, a converter circuit, electrical equipment, a control method for a PFC circuit in a refrigeration system, a computer-readable storage medium, a controller, and a refrigeration system according to embodiments of the present disclosure will be described.

[0047] Figure 1 is a hardware topology diagram of a converter circuit according to one embodiment of the present disclosure.

[0048] As shown in Figure 1, the converter circuit 300 according to the embodiment of this disclosure is suitable for converting an input AC power supply into a DC power supply and supplying power to a motor. The converter circuit 300 comprises a bridge circuit 310, an inductor L1, a capacitor C1, and a controller 320.

[0049] The bridge circuit 310 comprises multiple switch transistors, which are connected in a bridge configuration, forming an input terminal and an output terminal.

[0050] It is important to explain that a circuit in which multiple switch transistors are connected in a bridge configuration may be a half-bridge circuit, an H-bridge circuit, a three-phase bridge circuit, etc., and is not specifically limited to these.

[0051] Inductor L1 is connected between the AC power supply and the input terminal of the bridge circuit 310. Inductor L1 can store the power supplied from the AC power supply as energy and release this energy to boost the voltage and improve the power factor.

[0052] Capacitor C1 is connected to the output terminal of the bridge circuit 310 and is suitable for stabilizing the output voltage of the bridge circuit 310 and providing a DC power supply.

[0053] The controller 320 is configured to acquire the motor torque, control multiple switch transistors based on the motor torque, and switch the operating mode of the converter circuit 300, the operating modes of the converter circuit 300 include synchronous rectification mode and high-frequency PFC mode.

[0054] Specifically, electrical energy supplied from the AC power supply is input to the bridge circuit 310 via inductor L1 and converted. Capacitor C1 smooths the voltage output from the bridge circuit 310 to a DC voltage, which can then power the motor. During motor operation, the controller 320 acquires the motor torque in real time and controls multiple switch transistors based on the motor torque to control whether the converter circuit 300 operates in synchronous rectification mode or in high-frequency PFC mode. For example, when the motor starts up and is operating, the motor torque is high, and the controller 320 can control the converter circuit 300 to operate directly in high-frequency PFC mode. When the motor is in a stable operating stage, the motor torque is low, and the controller 320 can control the converter circuit 300 to operate in synchronous rectification mode. It is important to understand that when the converter circuit 300 operates in high-frequency PFC mode, the switch transistors are in high-frequency operation mode, resulting in large switching losses. When the converter circuit 300 operates in synchronous rectification mode, the switch transistors are in low-frequency operation mode, resulting in smaller switching losses.

[0055] As a result, the converter circuit 300 according to the embodiment of this disclosure, in the process of converting the input AC power supply to a DC power supply and supplying power to the motor, acquires the actual torque of the motor and achieves a rapid and accurate switching operation between synchronous rectification mode and high-frequency PFC mode based on the motor torque, achieving high efficiency and energy saving objectives while ensuring high real-time performance, accurate switching, avoiding unnecessary power loss, and ensuring the reliability and stable operation of the motor.

[0056] According to one embodiment of the present disclosure, as shown in Figure 1, a plurality of switch transistors constitute 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 terminals, and both ends of the first bridge arm 311 or the second bridge arm 312 serving as output terminals, with the midpoint of the first bridge arm 311 connected to an AC power supply AC via an inductor L1.

[0057] Specifically, as shown in Figure 1, the first bridge arm 311 includes an upper bridge switch transistor Q1 and a lower bridge switch transistor Q2 connected in series with each other, and the second bridge arm 312 includes an upper bridge switch transistor Q3 and a lower bridge switch transistor Q4 connected in series with each other. The upper bridge switch transistor Q1 and lower bridge switch transistor Q2 in the first bridge arm 311 and the upper bridge switch transistor Q3 and lower bridge switch transistor Q4 in the second bridge arm 312 constitute a bridge circuit 310, and the upper bridge switch transistor Q1 and lower bridge switch transistor Q2 in the first bridge arm 311 and the upper bridge switch transistor Q3 and lower bridge switch transistor Q4 in the second bridge arm 312 all have parasitic diodes that allow 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 transistor Q1 and the lower bridge switch transistor Q2 in the first bridge arm 311. The positive terminal of capacitor C1 is connected to the drain of the upper bridge switch transistor Q1 in the first bridge arm 311 and the drain of the upper bridge switch transistor Q3 in the second bridge arm 312, while the negative terminal is connected to the source of the lower bridge switch transistor Q2 in the first bridge arm 311 and the drain of the lower bridge switch transistor Q4 in the second bridge arm 312. The controller 320 is connected to the control terminals of each switch transistor. The controller 320 can also collect the voltage VAC of the input AC power supply, the current IAC flowing through the inductor L1, and the bus voltage VDC.

[0058] According to one embodiment of the present disclosure, the upper bridge switch transistor Q1 and the lower bridge switch transistor Q2 in the first bridge arm 311 are configured as high-speed transistors, and the upper bridge switch transistor Q3 and the lower bridge switch transistor Q4 in the second bridge arm 312 are configured as low-speed transistors. As a result, the reverse recovery time of the upper bridge switch transistor Q1 and the lower bridge switch transistor Q2 in the first bridge arm 311 is faster than the reverse recovery time of the upper bridge switch transistor Q3 and the lower bridge switch transistor Q4 in the second bridge arm 312, and in high-frequency PFC mode, the controller 320 can control the high-frequency conduction or disconnection of the upper bridge switch transistor Q1 and the lower bridge switch transistor Q2 in the first bridge arm 311.

[0059] In some embodiments, the switching element in the high-speed transistor is either a silicon carbide MOSFET or a gallium nitride MOSFET, as can be selected.

[0060] According to one embodiment of the present disclosure, when the converter circuit 300 operates in synchronous rectification mode, the upper bridge switch transistor Q1 and the lower bridge switch transistor Q2 in the first bridge arm 311 are connected or disconnected based on the polarity of the AC power supply, and the upper bridge switch transistor Q3 and the lower bridge switch transistor Q4 in the second bridge arm 312 are connected or disconnected based on the magnitude and polarity of the current flowing through the inductor L1.

[0061] Specifically, when the converter circuit 300 operates in synchronous rectification mode, the controller 320 can control the conduction or disconnection of the upper bridge switch transistor Q1 and the lower bridge switch transistor Q2 in the first bridge arm 311 based on the polarity of the AC power supply AC, and can control the conduction or disconnection of the upper bridge switch transistor Q3 and the lower bridge switch transistor Q4 in the second bridge arm 312 based on the magnitude and polarity of the current flowing through the inductor L1. In the time series for controlling the switch transistors in synchronous rectification mode, as shown in Figure 2, the voltage of the AC power supply AC is VAC and the current through the inductor L1 is IAC. Referring to Figures 1 and 2, during the positive half-cycle of the AC power supply, the controller 320 controls the conduction of the upper bridge switch transistor Q1 in the first bridge arm 311 and the disconnection of the lower bridge switch transistor Q2 in the first bridge arm 311. The AC power supply, inductor L1, the parasitic diode of the upper bridge switch transistor Q1 in the first bridge arm 311, capacitor C1, the parasitic diode of the lower bridge switch transistor Q4 in the second bridge arm 312, and the AC power supply form a circuit, and when the current IAC crosses zero, the controller 32 O controls the conduction of the lower bridge switch transistor Q4 in the second bridge arm 312. The AC power supply AC, inductor L1, upper bridge switch transistor Q1 in the first bridge arm 311, capacitor C1, lower bridge switch transistor Q4 in the second bridge arm 312, and AC power supply AC form a circuit. The flow of current IAC is as shown by the dashed line in Figure 3. This prevents the parasitic diode of the lower bridge switch transistor Q4 in the second bridge arm 312 from burning out and reduces conduction loss.Similarly, during the negative half-cycle of the AC power supply, the controller 320 controls the conduction of the lower bridge switch transistor Q2 in the first bridge arm 311 and the disconnection of the upper bridge switch transistor Q1 in the first bridge arm 311. The AC power supply, the parasitic diode of the upper bridge switch transistor Q3 in the second bridge arm 312, capacitor C1, the lower bridge switch transistor Q2 in the first bridge arm 311, inductor L1, and AC power supply form a circuit, and when the current IAC crosses zero, the controller 320 controls the second bridge switch. The conduction of the upper bridge switch transistor Q3 in the second bridge arm 312 is controlled, and the flow of current IAC is as shown by the dashed line in Figure 4. The AC power supply AC, the upper bridge switch transistor Q3 in the second bridge arm 312, capacitor C1, the lower bridge switch transistor Q2 in the first bridge arm 311, inductor L1, and AC power supply AC form a circuit and current IAC flows. This prevents the parasitic diode of the upper bridge switch transistor Q3 in the second bridge arm 312 from burning out and reduces conduction loss.

[0062] According to other embodiments of the present disclosure, when the converter circuit 300 operates in synchronous rectification mode, the upper bridge switch transistor Q3 and the lower bridge switch transistor Q4 in the second bridge arm 312 conduct or disconnect based on the polarity of the AC power supply, and the upper bridge switch transistor Q1 and the lower bridge switch transistor Q2 in the first bridge arm 311 conduct or disconnect based on the magnitude and polarity of the current flowing through the inductor L1.

[0063] Specifically, when the converter circuit 300 operates in synchronous rectification mode, the controller 320 can control the conduction or disconnection of the upper bridge switch transistor Q3 and the lower bridge switch transistor Q4 in the second bridge arm 312 based on the polarity of the AC power supply AC, and can control the conduction or disconnection of the upper bridge switch transistor Q1 and the lower bridge switch transistor Q2 in the first bridge arm 311 based on the magnitude and polarity of the current flowing through the inductor L1. As shown in Figure 5, the time series for controlling the switch transistors in synchronous rectification mode is such that the voltage of the AC power supply AC is VAC and the current through the inductor L1 is IAC. Referring to Figures 1 and 5, during the positive half-cycle of the AC power supply, the controller 320 controls the conduction of the upper bridge switch transistor Q3 in the second bridge arm 312 and the disconnection of the lower bridge switch transistor Q4 in the second bridge arm 312. The AC power supply, inductor L1, parasitic diode of the lower bridge switch transistor Q2 in the first bridge arm 311, capacitor C1, upper bridge switch transistor Q3 in the second bridge arm 312, and AC power supply form a circuit. When the current IAC crosses zero, the controller 320 controls the conduction of the lower bridge switch transistor Q2 in the first bridge arm 311. The AC power supply, inductor L1, lower bridge switch transistor Q2 in the first bridge arm 311, capacitor C1, upper bridge switch transistor Q3 in the second bridge arm 312, and AC power supply form a circuit. The flow of current IAC, as shown by the dashed line in Figure 6, prevents the parasitic diode of the lower bridge switch transistor Q2 in the first bridge arm 311 from burning out and reduces conduction loss.Similarly, during the negative half-cycle of the AC power supply, the controller 320 controls the conduction of the lower bridge switch transistor Q4 in the second bridge arm 312 and the disconnection of the upper bridge switch transistor Q3 in the second bridge arm 312. The AC power supply, the lower bridge switch transistor Q4 in the second bridge arm 312, capacitor C1, the parasitic diode of the upper bridge switch transistor Q1 in the first bridge arm 311, inductor L1, and AC power supply form a circuit, and when the current IAC crosses zero, the controller 320 controls the first The conduction of the upper bridge switch transistor Q1 in the bridge arm 311 is controlled, and the flow of current IAC is as shown by the dashed line in Figure 7. The AC power supply AC, the lower bridge switch transistor Q4 in the second bridge arm 312, capacitor C1, the upper bridge switch transistor Q1 in the first bridge arm 311, inductor L1, and AC power supply AC form a circuit and current IAC flows, preventing the parasitic diode of the upper bridge switch transistor Q1 in the first bridge arm 311 from burning out and reducing conduction loss.

[0064] According to one embodiment of the present disclosure, when the converter circuit 300 operates in high-frequency PFC mode, the upper bridge switch transistor Q3 and the lower bridge switch transistor Q4 in the second bridge arm 312 are connected or disconnected based on the polarity of the AC power supply, and the upper bridge switch transistor Q1 and the lower bridge switch transistor Q2 in the first bridge arm 311 are connected or disconnected alternately based on a predetermined frequency.

[0065] Specifically, when the converter circuit 300 operates in high-frequency PFC mode, the controller 320 controls the conduction or disconnection of the upper bridge switch transistor Q3 and the lower bridge switch transistor Q4 in the second bridge arm 312 based on the polarity of the AC power supply, and also controls the conduction or disconnection of the upper bridge switch transistor Q3 and the lower bridge switch transistor Q4 in the second bridge arm 312 based on the magnitude and polarity of the current flowing through the inductor L1. The time series for controlling the switch transistors in high-frequency PFC mode is shown in Figure 8. Referring to Figures 1 and 8, during the positive half-cycle of the AC power supply, the controller 320 controls the conduction of the lower bridge switch transistor Q4 in the second bridge arm 312 and the disconnection of the upper bridge switch transistor Q3 in the second bridge arm 312, and also controls the conduction of the lower bridge switch transistor Q2 in the first bridge arm 311 and the disconnection of the upper bridge switch transistor Q1. At this time, the AC power supply, inductor L1, lower bridge switch transistor Q2 in the first bridge arm 311, lower bridge switch transistor Q4 in the second bridge arm 312, and AC power supply form a circuit, and the flow of current IAC is as shown in Figure 9. As shown by the line, the AC power supply charges the inductor L1, then controls the conduction of the upper bridge switch transistor Q1 and the disconnection of the lower bridge switch transistor Q2 in the first bridge arm 311. The AC power supply, inductor L1, upper bridge switch transistor Q1 in the first bridge arm 311, capacitor C1, lower bridge switch transistor Q4 in the second bridge arm 312, and AC power supply form a circuit. The flow of current IAC, as shown by the dashed line in Figure 10, releases the power stored in the inductor L1, which is superimposed with the voltage of the AC power supply, thereby boosting and charging capacitor C1, thereby achieving voltage boosting and power factor correction. After repeating this cycle, the controller 320 controls the upper bridge switch transistor Q1 and lower bridge switch transistor Q2 in the first bridge arm 311 to alternately conduct or disconnect based on a predetermined frequency.

[0066] During the negative half-cycle of the AC power supply, the controller 320 controls the conduction of the upper bridge switch transistor Q3 in the second bridge arm 312 and the disconnection of the lower bridge switch transistor Q4 in the second bridge arm 312, and first controls the conduction of the upper bridge switch transistor Q1 in the first bridge arm 311 and the disconnection of the lower bridge switch transistor Q2 (not shown in the diagram). At this time, the AC power supply, the upper bridge switch transistor Q3 in the second bridge arm 312, the upper bridge switch transistor Q1 in the first bridge arm 311, the inductor L1, and the AC power supply AC cycle A circuit is formed, the AC power supply charges the inductor L1, and then controls the conduction of the lower bridge switch transistor Q2 in the first bridge arm 311 and the disconnection of the upper bridge switch transistor Q1. Although not shown, the AC power supply, the upper bridge switch transistor Q3 in the second bridge arm 312, capacitor C1, the lower bridge switch transistor Q2 in the first bridge arm 311, inductor L1, and AC power supply form a circuit, the power stored in inductor L1 is released and superimposed on the voltage of the AC power supply, thereby boosting and charging capacitor C1, thereby achieving voltage boosting and power factor correction. After repeating this cycle, the controller 320 controls the upper bridge switch transistor Q1 and the lower bridge switch transistor Q2 in the first bridge arm 311 to alternately conduct or disconnect based on a predetermined frequency.

[0067] According to one embodiment of the present disclosure, the step of conducting or disconnecting the upper bridge switch transistor and the lower bridge switch transistor in the first bridge arm 311 or the second bridge arm 312 based on the polarity of the input AC power supply includes the step of determining the zero-crossing point of the input AC power supply and controlling the conduction or disconnection of the upper bridge switch transistor and the lower bridge switch transistor at the zero-crossing point.

[0068] Specifically, the controller 320 detects the voltage of the AC power supply in real time to determine the zero-crossing point of the AC power supply, and the controller 320 controls the conduction or disconnection of the upper bridge switch transistor and the lower bridge switch transistor at the zero-crossing point.

[0069] According to one embodiment of the present disclosure, when the converter circuit 300 operates in synchronous rectification mode, the upper bridge switch transistor Q1 and the lower bridge switch transistor Q2 in the first bridge arm 311 conduct or disconnect based on the polarity of the AC power supply, thereby making the first bridge arm 311 a zero-voltage conducting bridge arm, and the upper bridge switch transistor Q3 and the lower bridge switch transistor Q4 in the second bridge arm 312 conduct or disconnect based on the polarity of the AC power supply, thereby making the second bridge arm 312 a zero-voltage conducting bridge arm.

[0070] In other words, when the converter circuit 300 operates in synchronous rectification mode, the upper and lower bridge switch transistors in one bridge arm conduct or disconnect based on the polarity of the AC power supply, making the bridge arm a zero-voltage conducting bridge arm.

[0071] According to one 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 a zero-voltage conducting bridge arm based on the total operating time of the first bridge arm 311 and the total operating time of the second bridge arm 312.

[0072] Specifically, as can be seen from Figures 2 and 5, when the converter circuit 300 operates in synchronous rectification mode, the operating time of the zero-voltage conduction bridge arm is longer than that of the non-zero-voltage conduction bridge arm. The controller 320 statistically analyzes the total operating time of the two bridge arms, compares their total operating times, and controls the bridge arm with the longer total operating time to become the zero-voltage conduction bridge arm. By balancing the operating times of the two bridge arms, the operating time of the switch transistors in the bridge arms can be made more uniform, thereby extending the service life of the converter circuit 300.

[0073] According to other embodiments of the present disclosure, the controller 320 is further configured to determine the zero-voltage conduction bridge arm when the converter circuit 300 is currently operating in synchronous rectification mode based on the zero-voltage conduction bridge arm when the converter circuit 300 was previously operating in synchronous rectification mode.

[0074] According to one embodiment of the present disclosure, the controller 320 is further configured to control the converter circuit 300 to switch to high-frequency PFC mode when the torque is greater than or equal to a first predetermined value, and to switch to synchronous rectification mode when the torque is less than the first predetermined value. The first predetermined value can be defined according to the actual situation and is not limited thereto.

[0075] Specifically, after acquiring the motor torque, the controller 320 can compare the torque with a first predetermined value. If the torque is greater than or equal to the first predetermined value, the controller 320 controls the converter circuit 300 to switch to high-frequency PFC mode. If the torque is less than the first predetermined value, the controller 320 controls the converter circuit 300 to switch to synchronous rectification mode.

[0076] According to other embodiments of the present disclosure, the controller 320 further acquires the motor speed, determines the torque based on the speed difference between the motor speed and the target speed, and determines the product of the motor speed and the torque. Herein, if the product is greater than or equal to a second predetermined value, the controller 320 controls the converter circuit 300 to switch to high-frequency PFC mode and operate; and if the product is less than the second predetermined value, the controller 320 controls the converter circuit 300 to switch to synchronous rectification mode and operate. The second predetermined value can be defined according to the actual situation and is not limited thereto.

[0077] Specifically, as shown in Figure 11, the controller 320 obtains the motor speed, calculates the difference between the speed and the target speed, then performs PI control on the motor speed difference to obtain the motor torque, multiplies the compressor speed and torque, compares the product with a second predetermined value, and if the product is greater than or equal to the second predetermined value, the controller 320 controls the converter circuit 300 to switch to high-frequency PFC mode and operate; if the product is less than the second predetermined value, the controller 320 controls the converter circuit 300 to switch to synchronous rectification mode and operate.

[0078] In some embodiments of this disclosure, the value of Te can be calculated using the formula Te = 3 / 2 * P [Ke * Iq + (Ld - Lq) Id * Iq], where P is the number of pole pairs of the motor, Ke is the back electromotive force of the motor, Ld is the D-axis inductance value of the motor, Lq is the Q-axis inductance value of the motor, Id is the D-axis control current value of the motor, and Iq is the Q-axis control current value of the motor. The controller can obtain the motor torque by acquiring the number of pole pairs P of the motor, the back electromotive force Ke of the motor, the D-axis inductance value Ld of the motor, the Q-axis inductance value Lq of the motor, the D-axis control current value Id of the motor, and the Q-axis control current value Iq of the motor, and substituting these values ​​into the above formula.

[0079] As described above, the converter circuit according to the embodiment of this disclosure, in the process of converting the input AC power supply into a DC power supply and supplying power to the motor, acquires the actual torque of the motor and achieves a rapid and accurate switching operation between synchronous rectification mode and high-frequency PFC mode based on the motor torque. This achieves high efficiency and energy saving objectives while ensuring real-time performance, accurate switching, avoiding unnecessary power loss, and ensuring the reliability and stable operation of the motor.

[0080] In accordance with the above embodiments, this disclosure further proposes electrical equipment.

[0081] Figure 12 is a schematic block diagram of an electrical device according to an embodiment of the present disclosure.

[0082] As shown in Figure 12, the electrical equipment 400 according to the embodiment of the present disclosure comprises a motor 410 and a converter circuit 300 described in the above embodiment, which is suitable for the converter circuit to convert the input AC power supply into a DC power supply and supply power to the motor.

[0083] The electrical equipment according to the embodiments of this disclosure, based on the converter circuit described in the above embodiments, converts the input AC power supply to a DC power supply and supplies power to the motor. In this process, it can achieve rapid and accurate switching between synchronous rectification mode and high-frequency PFC mode based on the motor torque, resulting in high real-time performance, accurate switching, avoidance of unnecessary power loss, and achieving high efficiency and energy saving while ensuring motor reliability and stable operation.

[0084] In accordance with the above embodiments, this disclosure further provides a method for controlling a PFC circuit in a refrigeration system.

[0085] Figure 13 is a flowchart of a control method for a PFC circuit in a refrigeration system according to an embodiment of the present disclosure.

[0086] In some embodiments of this disclosure, the refrigeration equipment can adjust its power factor and increase the DC bus voltage by a PFC circuit, which mainly provides power to the compressor and fan motor. The PFC circuit includes a synchronous rectification mode and a high-frequency PFC mode.

[0087] When refrigeration equipment starts up and begins operation, the input power is high, and the high-frequency PFC mode is activated directly. However, when the input power is not high, there is no need to activate the high-frequency PFC mode, and the requirement to adjust the power factor of the refrigeration equipment can be met by switching from the high-frequency PFC mode to the synchronous rectification mode. When the PFC circuit operates in high-frequency PFC mode, the control transistor is in high-frequency operation mode, resulting in large switching losses. When the PFC circuit operates in synchronous rectification mode, the control transistor is in low-frequency operation mode, resulting in small switching losses.

[0088] As shown in Figure 13, the control method for the PFC circuit in a refrigeration system according to an embodiment of the present disclosure is as follows: S1 determines the torque of the compressor in the refrigeration equipment, This may include S2, which controls the PFC circuit to switch between synchronous rectification mode and high-frequency PFC mode based on the compressor torque.

[0089] The control method for a PFC circuit in a refrigeration system according to the embodiments of this disclosure controls the PFC circuit to switch between synchronous rectification mode and high-frequency PFC mode by determining the torque of the compressor in the refrigeration system. Thus, because the switching point between the synchronous rectification mode and high-frequency PFC mode of the PFC circuit is determined by the torque of the compressor, it has higher real-time performance and accuracy, the switching is precise, unnecessary power loss can be avoided, and the objectives of high efficiency and energy saving can be achieved while ensuring motor reliability and stable operation.

[0090] According to one embodiment of the present disclosure, the step of controlling a PFC circuit to switch between a synchronous rectification mode and a high-frequency PFC mode based on the torque of a compressor includes the steps of controlling the PFC circuit to operate in high-frequency PFC mode when the torque is greater than or equal to a first predetermined value, and controlling the PFC circuit to operate in synchronous rectification mode when the torque is less than the first predetermined value. The first predetermined value can be set according to the specific parameters of the refrigeration equipment and is not limited thereto.

[0091] According to one embodiment of the present disclosure, the step of determining the torque of a compressor in a refrigeration system includes the steps of obtaining the rotational speed of the compressor and determining the torque of the compressor based on the rotational speed difference between the rotational speed of the compressor and the target rotational speed.

[0092] According to one embodiment of the present disclosure, the step of obtaining the rotational speed of the compressor includes the step of obtaining the rotational speed of the compressor using a rotational speed sensor.

[0093] In other words, by detecting the compressor with a rotation speed sensor, the compressor's rotation speed can be obtained in real time. The rotation speed sensor may also be a Hall sensor.

[0094] According to other embodiments of the present disclosure, the step of obtaining the compressor speed includes observing the rotor position of the compressor using a magnetic flux observer and obtaining the compressor speed.

[0095] Specifically, the stator flux angle and magnitude of the flux are recognized by the magnetic flux observer, and the rotor position can be obtained. This allows the compressor motor rotor speed to be estimated, and the compressor rotational speed is obtained. Furthermore, after obtaining the compressor rotational speed, the controller calculates the difference between the rotational speed and the target rotational speed, and then performs PI control on the difference in compressor rotational speed to obtain the compressor torque. The controller compares the torque with a first predetermined value, and if the torque is greater than or equal to the first predetermined value, the controller controls the PFC circuit to switch to high-frequency PFC mode. If the torque is less than the first predetermined value, the controller controls the PFC circuit to switch to synchronous rectification mode.

[0096] In some embodiments of this disclosure, the value of Te can be obtained by the formula Te = 3 / 2 * P [Ke * Iq + (Ld - Lq) Id * Iq], where P is the number of pole pairs of the motor, Ke is the back electromotive force of the motor, Ld is the D-axis inductance value of the motor, Lq is the Q-axis inductance value of the motor, Id is the D-axis control current value of the motor, and Iq is the Q-axis control current value of the motor. The controller can obtain the number of pole pairs P of the compressor, the back electromotive force Ke, the D-axis inductance value Ld, the Q-axis inductance value Lq, the D-axis control current value Id, and the Q-axis control current value Iq, substitute them into the above formula, and calculate to obtain the torque of the compressor.

[0097] According to other embodiments of the present disclosure, the step of controlling a PFC circuit to switch between a synchronous rectification mode and a high-frequency PFC mode based on the torque of a compressor includes the steps of: determining the product of the compressor speed and torque; controlling the PFC circuit to switch to and operate in high-frequency PFC mode if the product is greater than or equal to a second predetermined value; and controlling the PFC circuit to switch to and operate in synchronous rectification mode if the product is less than the second predetermined value. The second predetermined value can be set according to the specific parameters of the refrigeration equipment and is not limited thereto.

[0098] Specifically, after the controller obtains the compressor's rotational speed, it calculates the difference between the rotational speed and the target rotational speed. Next, it obtains the compressor's torque by applying PI control to the difference in the compressor's rotational speed. At the same time, it multiplies the actual compressor's rotational speed and torque, compares the product with a second predetermined value, and if the product is greater than or equal to the second predetermined value, the controller controls the PFC circuit to switch to high-frequency PFC mode. If the product is less than the second predetermined value, the controller controls the PFC circuit to switch to synchronous rectification mode.

[0099] According to one embodiment of the present disclosure, the PFC circuit comprises an inductor and a bridge circuit, the bridge circuit includes a plurality of switch transistors, the plurality of switch transistors constituting a first bridge arm and a second bridge arm connected in parallel, one of the first and second bridge arms being connected to an inductor, the upper bridge switch transistor and lower bridge switch transistor in the first bridge arm conduct or disconnect based on the polarity of the input AC power supply, and the upper bridge switch transistor and lower bridge switch transistor in the second bridge arm conduct or disconnect based on the magnitude and polarity of the current flowing through the inductor, in which case the PFC circuit operates in synchronous rectification mode, or the upper bridge switch transistor in the second bridge arm The PFC circuit operates in synchronous rectification mode when the ridge switch transistor and lower bridge switch transistor conduct or disconnect based on the polarity of the input AC power supply, and the upper bridge switch transistor and lower bridge switch transistor in the first bridge arm conduct or disconnect based on the magnitude and polarity of the current flowing through the inductor. The PFC circuit operates in high-frequency PFC mode when the upper bridge switch transistor and lower bridge switch transistor in the bridge arm connected to the inductor conduct or disconnect alternately based on a predetermined frequency, and the upper bridge switch transistor and lower bridge switch transistor in the bridge arm not connected to the inductor conduct or disconnect based on the polarity of the input AC power supply.

[0100] According to one embodiment of the present disclosure, the upper bridge switch transistor and the lower bridge switch transistor in a first bridge arm or a second bridge arm are connected or disconnected based on the polarity of an input AC power supply, which includes the steps of determining a zero-crossing point of the input AC power supply and controlling the connection or disconnection of the upper bridge switch transistor and the lower bridge switch transistor at the zero-crossing point.

[0101] It is necessary to explain that the above-mentioned PFC circuit corresponds to the converter circuit described in the embodiment of the first aspect of this disclosure, the above-mentioned compressor corresponds to the motor, and for the specific operating principle of the PFC circuit, refer to the specific description of the converter circuit described in the embodiment of the first aspect of this disclosure, which will not be repeated here.

[0102] As described above, the control method for a PFC circuit in a refrigeration system according to the embodiments of this disclosure controls the PFC circuit to switch between synchronous rectification mode and high-frequency PFC mode by determining the torque of the compressor in the refrigeration system. In this way, because the switching point between the synchronous rectification mode and high-frequency PFC mode of the PFC circuit is determined by the torque of the compressor, it has higher real-time performance and accuracy, the switching is precise, unnecessary power loss can be avoided, and the objectives of high efficiency and energy saving are achieved while ensuring motor reliability and stable operation.

[0103] In accordance with the above embodiments, the present disclosure further proposes a computer-readable storage medium.

[0104] The computer-readable storage medium in the embodiments of this disclosure stores a control program for the PFC circuit in the refrigeration equipment, and when the program is executed by the processor, it executes the control method for the PFC circuit in the refrigeration equipment described above.

[0105] The computer-readable storage medium according to the embodiments of this disclosure controls the PFC circuit to switch between synchronous rectification mode and high-frequency PFC mode by determining the torque of the compressor in the refrigeration equipment by performing the control method for the PFC circuit in the above embodiments. Thus, because the switching point between the synchronous rectification mode and high-frequency PFC mode of the PFC circuit is determined by the torque of the compressor, it has higher real-time performance and accuracy, the switching is precise, unnecessary power loss can be avoided, and the objectives of high efficiency and energy saving can be achieved while ensuring motor reliability and stable operation.

[0106] In response to the above embodiments, this disclosure further proposes a controller.

[0107] Figure 14 is a schematic block diagram of a controller according to an embodiment of the present disclosure.

[0108] As shown in Figure 14, the controller 200 according to the embodiment of the present disclosure includes a memory 210, a processor 220, and a control program for a PFC circuit in a refrigeration system that is stored in the memory 210 and can be operated by the processor 220. When the processor 220 executes the program, it implements the control method for the PFC circuit in the refrigeration system.

[0109] The controller according to the embodiment of this disclosure implements the above-described method for controlling the PFC circuit in the refrigeration equipment by executing a control program for the PFC circuit in the refrigeration equipment stored in memory by a processor. This controls the PFC circuit to switch between synchronous rectification mode and high-frequency PFC mode by determining the torque of the compressor in the refrigeration equipment. Thus, because the switching point between the synchronous rectification mode and high-frequency PFC mode of the PFC circuit is determined by the torque of the compressor, it has higher real-time performance and accuracy, the switching is precise, unnecessary power loss can be avoided, and the objectives of high efficiency and energy saving can be achieved while ensuring motor reliability and stable operation.

[0110] In accordance with the above embodiments, the present disclosure further provides refrigeration equipment.

[0111] Figure 15 is a schematic block diagram of a refrigeration system according to an embodiment of the present disclosure.

[0112] As shown in Figure 15, the refrigeration equipment 100 according to the embodiment of this disclosure may include a PFC circuit 110, a compressor 120, and a controller 130.

[0113] The PFC circuit 110 includes a synchronous rectification mode and a high-frequency PFC mode. The controller 130 is used to determine the compressor torque and to control the PFC circuit to switch between the synchronous rectification mode and the high-frequency PFC mode based on the compressor torque.

[0114] According to one embodiment of the present disclosure, the controller 130 controls the PFC circuit to switch between a synchronous rectification mode and a high-frequency PFC mode based on the torque of the compressor. Specifically, it is used to control the PFC circuit to switch to the high-frequency PFC mode and operate when the torque is greater than or equal to a first predetermined value, and to control the PFC circuit to switch to the synchronous rectification mode and operate when the torque is less than the first predetermined value.

[0115] According to one embodiment of the present disclosure, the controller 130 is used to determine the torque of a compressor in a refrigeration system, specifically to obtain the rotational speed of the compressor and to determine the torque of the compressor based on the rotational speed difference between the compressor's rotational speed and a target rotational speed.

[0116] According to other embodiments of the present disclosure, the controller 130 controls the PFC circuit to switch between a synchronous rectification mode and a high-frequency PFC mode based on the compressor torque, and is used specifically to determine the product of the compressor speed and torque, to control the PFC circuit to switch to and operate in high-frequency PFC mode if the product is greater than or equal to a second predetermined value, and to control the PFC circuit to switch to and operate in synchronous rectification mode if the product is less than the second predetermined value.

[0117] 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 switch transistors, the plurality of switch transistors forming a first bridge arm and a second bridge arm connected in parallel, one of the first and second bridge arms is connected to an inductor, the upper bridge switch transistor and lower bridge switch transistor in the first bridge arm conduct or disconnect based on the polarity of the input AC power supply, and the upper bridge switch transistor and lower bridge switch transistor in the second bridge arm conduct or disconnect based on the magnitude and polarity of the current flowing through the inductor, the PFC circuit operates in synchronous rectification mode, or the upper bridge switch transistor in the second bridge arm conducts or disconnects based on the magnitude and polarity of the current flowing through the inductor. The PFC circuit operates in synchronous rectification mode when the ridge switch transistor and lower bridge switch transistor conduct or disconnect based on the polarity of the input AC power supply, and the upper bridge switch transistor and lower bridge switch transistor in the first bridge arm conduct or disconnect based on the magnitude and polarity of the current flowing through the inductor. The PFC circuit operates in high-frequency PFC mode when the upper bridge switch transistor and lower bridge switch transistor in the bridge arm connected to the inductor conduct or disconnect alternately based on a predetermined frequency, and the upper bridge switch transistor and lower bridge switch transistor in the bridge arm not connected to the inductor conduct or disconnect based on the polarity of the input AC power supply.

[0118] According to one embodiment of the present disclosure, the upper bridge switch transistor and the lower bridge switch transistor in a first bridge arm or a second bridge arm are connected or disconnected based on the polarity of an input AC power supply, which includes the steps of determining a zero-crossing point of the input AC power supply and controlling the connection or disconnection of the upper bridge switch transistor and the lower bridge switch transistor at the zero-crossing point.

[0119] According to one embodiment of the present disclosure, the controller 130 is used to acquire the rotational speed of the compressor, specifically by detecting the rotational speed of the compressor using a rotational speed sensor.

[0120] In other embodiments of the present disclosure, the controller 130 acquires the compressor speed, specifically by observing the compressor rotor position using a magnetic flux observer and acquiring the compressor speed. Details not disclosed in the refrigeration equipment of the embodiments of the present disclosure are referred to in the details disclosed in the method for controlling the PFC circuit in the refrigeration equipment of the embodiments of the present disclosure and are not specifically repeated here.

[0121] The refrigeration equipment according to the embodiments of this disclosure controls the PFC circuit to switch between synchronous rectification mode and high-frequency PFC mode based on the compressor torque. Thus, because the switching point between synchronous rectification mode and high-frequency PFC mode of the PFC circuit is determined by the compressor torque, it has higher real-time performance and accuracy, the switching is precise, unnecessary power loss can be avoided, and high efficiency and energy saving objectives can be achieved while ensuring motor reliability and stable operation.

[0122] It is necessary to explain that the logic and / or steps shown in the flowchart or otherwise described herein can be thought of, for example, as an ordered list of executable instructions for realizing a logical function, which can be specifically realized on any computer-readable medium and used in or in combination with instruction execution systems, devices or equipment (for example, computer-based systems, which include a processor or a system that reads instructions from an instruction execution system, device or equipment and executes those instructions). For the purposes of this specification, “computer-readable medium” may be any device that stores, communicates, propagates or transmits a program, which can be used in combination with an instruction execution system, device or equipment or such instruction execution systems, devices or equipment. More specific examples of computer-readable mediums (a non-exclusive list) include electrical connections having one or more wires (electronic devices), portable computer disk cartridges (disk drives), random access memory (RAM), read-only memory (ROM), erasable and editable read-only memory (EPROM or flash memory), optical fiber devices, and portable disk read-only memory (CDROM). Furthermore, the computer-readable medium may also be paper or other suitable medium on which the program is printed. For example, the program may be acquired electronically by optically scanning paper or other suitable medium, and then editing, interpreting, or processing it in any other suitable manner, and then stored in computer memory.

[0123] It should be understood that each part of this disclosure can be implemented in hardware, software, firmware, or a combination thereof. In the embodiments described above, multiple steps or methods can be implemented in software or firmware stored in memory and executed by an appropriate instruction execution system. When implemented in hardware, as in other embodiments, it can be implemented in any or a combination of technologies known in the art, such as discrete logic circuits having logic gate circuits for implementing logic functions for data signals, dedicated integrated circuits having appropriate combinational logic gate circuits, programmable gate arrays (PGAs), and field-programmable gate arrays (FPGAs).

[0124] In this specification, reference terms such as “one embodiment,” “several embodiments,” “example,” “specific example,” or “several examples” refer to specific features, structures, materials, or characteristics described in combination with such embodiments or examples, which are included in at least one embodiment or example of the present invention. In this specification, illustrative descriptions of the above terms do not necessarily apply to the same embodiment or example. Furthermore, specific features, structures, materials, or characteristics described can be combined in an appropriate manner in any or more embodiments or examples.

[0125] Furthermore, the terms “first” and “second” are used solely for descriptive purposes and should not be understood as indicating the number of technical features of relative importance, whether explicitly or implicitly stated or shown. Therefore, features limited by “first” and “second” may explicitly or implicitly include at least one such feature. In this description, “multiple” means at least two, for example, two, three, etc., unless otherwise specified.

[0126] In this disclosure, terms such as “attachment,” “connection,” “connection,” and “fixing” should be understood broadly unless otherwise specified and limited, and may include, for example, being fixedly connected, detachably connected, integrated, mechanically connected, electrically connected, directly connected, indirectly connected via an intermediate medium, or internal communication or interaction relationship between two elements. Those skilled in the art will understand the specific concepts of the aforementioned technical terms in this invention depending on the specific circumstances.

[0127] Although examples have been shown and described in this disclosure, these examples are illustrative and should not be understood as limiting this disclosure. Those skilled in the art will understand that various changes, modifications, substitutions, and variations are possible in the examples within the scope of this disclosure.

Claims

1. A converter circuit suitable for converting an input AC power supply into a DC power supply and supplying power to a motor, A bridge circuit comprising multiple switch transistors, wherein the multiple switch transistors are connected in a bridge configuration and the input terminal and output terminal are formed, An inductor connected between the AC power supply and the input terminal, A capacitor connected to the output terminal, suitable for stabilizing the output voltage of the bridge circuit and providing the DC power supply, A converter circuit comprising: a controller configured to acquire the torque of the motor, control the plurality of switch transistors based on the torque of the motor, and switch the operating mode of the converter circuit, including a synchronous rectification mode and a high-frequency PFC mode.

2. The converter circuit according to claim 1, wherein the plurality of switch transistors constitute 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 are the input terminals, both ends of the first bridge arm or the second bridge arm are the output terminals, and the midpoint of the first bridge arm is connected to the AC power supply via the inductor.

3. The converter circuit according to claim 2, wherein the upper bridge switch transistor and the lower bridge switch transistor in the first bridge arm are configured as high-speed transistors, and the upper bridge switch transistor and the lower bridge switch transistor in the second bridge arm are configured as low-speed transistors.

4. The converter circuit according to claim 3, wherein the switching element in the high-speed transistor is a silicon carbide MOSFET or a gallium nitride MOSFET.

5. The converter circuit according to any one of claims 2 to 4, wherein when the converter circuit operates in the synchronous rectification mode, the upper bridge switch transistor and the lower bridge switch transistor in the first bridge arm conduct or disconnect based on the polarity of the AC power supply, and the upper bridge switch transistor and the lower bridge switch transistor in the second bridge arm conduct or disconnect based on the magnitude and polarity of the current flowing through the inductor.

6. The converter circuit according to any one of claims 2 to 4, wherein when the converter circuit operates in the synchronous rectification mode, the upper bridge switch transistor and the lower bridge switch transistor in the second bridge arm conduct or disconnect based on the polarity of the AC power supply, and the upper bridge switch transistor and the lower bridge switch transistor in the first bridge arm conduct or disconnect based on the magnitude and polarity of the current flowing through the inductor.

7. The converter circuit according to any one of claims 3 to 6, wherein when the converter circuit operates in the high-frequency PFC mode, the upper bridge switch transistor and the lower bridge switch transistor in the second bridge arm are connected or disconnected based on the polarity of the AC power supply, and the upper bridge switch transistor and the lower bridge switch transistor in the first bridge arm are connected or disconnected alternately based on a predetermined frequency.

8. When the converter circuit operates in the synchronous rectification mode, When the upper bridge switch transistor and the lower bridge switch transistor in the first bridge arm conduct or disconnect based on the polarity of the AC power supply, the first bridge arm becomes a zero-voltage conducting bridge arm. The converter circuit according to any one of claims 2 to 7, wherein the upper bridge switch transistor and the lower bridge switch transistor in the second bridge arm conduct or disconnect based on the polarity of the AC power supply, thereby making the second bridge arm a zero-voltage conducting bridge arm.

9. The converter 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 conducting bridge arm based on the total operating time of the first bridge arm and the total operating time of the second bridge arm.

10. The converter circuit according to claim 8, further configured such that the controller determines the zero-voltage conduction bridge arm when the converter circuit operates in the synchronous rectification mode in the current operation, based on the zero-voltage conduction bridge arm when the converter circuit previously operated in the synchronous rectification mode.

11. The controller further, If the torque is greater than or equal to a first predetermined value, the converter circuit is controlled to switch to the high-frequency PFC mode and operate accordingly. The converter circuit according to any one of claims 1 to 10, configured to control the converter circuit to switch to the synchronous rectification mode and operate when the torque is less than a first predetermined value.

12. The controller further acquires the rotational speed of the motor, determines the torque based on the rotational speed difference between the motor's rotational speed and the target rotational speed, and determines the product of the motor's rotational speed and the torque. If the product is greater than or equal to a second predetermined value, the converter circuit is controlled to switch to the high-frequency PFC mode and operate accordingly. The converter circuit according to any one of claims 1 to 11, configured to control the converter circuit to switch to the synchronous rectification mode and operate when the product is smaller than a second predetermined value.

13. Motor and, An electrical device comprising a converter circuit according to any one of claims 1 to 12, which is suitable for converting an input AC power supply into a DC power supply and supplying power to the motor.

14. A control method for a PFC circuit in a refrigeration system, wherein the PFC circuit includes a synchronous rectification mode and a high-frequency PFC mode, and the control method is The steps include determining the torque of the compressor in the aforementioned refrigeration equipment, A method for controlling a PFC circuit in a refrigeration system, comprising the step of controlling the PFC circuit to switch between the synchronous rectification mode and the high-frequency PFC mode based on the torque of the compressor.

15. The step of controlling the PFC circuit to switch between the synchronous rectification mode and the high-frequency PFC mode based on the torque of the compressor is: The steps include controlling the PFC circuit to switch to the high-frequency PFC mode and operate when the torque is greater than or equal to a first predetermined value, The control method according to claim 14, comprising the step of controlling the PFC circuit to switch to the synchronous rectification mode and operate when the torque is less than a first predetermined value.

16. The step of determining the torque of the compressor in the aforementioned refrigeration equipment is: The steps include obtaining the rotational speed of the compressor, The control method according to claim 14 or 15, comprising the step of determining the torque of the compressor based on the rotational speed difference between the rotational speed of the compressor and a target rotational speed.

17. The step of controlling the PFC circuit to switch between the synchronous rectification mode and the high-frequency PFC mode based on the torque of the compressor is: The steps include determining the product of the compressor's rotational speed and torque, If the product is greater than or equal to a second predetermined value, the PFC circuit is controlled to switch to the high-frequency PFC mode and operate accordingly. The control method according to claim 16, further comprising the step of controlling the PFC circuit to switch to the synchronous rectification mode and operate if the product is smaller than a second predetermined value.

18. The PFC circuit includes an inductor and a bridge circuit, the bridge circuit includes a plurality of switch transistors, the plurality of switch transistors constitute a first bridge arm and a second bridge arm connected in parallel, and one of the first bridge arm and the second bridge arm is connected to the inductor. If the upper and lower bridge switch transistors in the first bridge arm are connected or disconnected based on the polarity of the input AC power supply, and the upper and lower bridge switch transistors in the second bridge arm are connected or disconnected based on the magnitude and polarity of the current flowing through the inductor, the PFC circuit operates in the synchronous rectification mode, or if the upper and lower bridge switch transistors in the second bridge arm are connected or disconnected based on the polarity of the input AC power supply, and the upper and lower bridge switch transistors in the first bridge arm are connected or disconnected based on the magnitude and polarity of the current flowing through the inductor, the PFC circuit operates in the synchronous rectification mode. The control method according to any one of claims 14 to 17, wherein the PFC circuit operates in the high-frequency PFC mode when the upper bridge switch transistor and the lower bridge switch transistor in a bridge arm connected to the inductor are alternately conducted or disconnected based on a predetermined frequency, and the upper bridge switch transistor and the lower bridge switch transistor in a bridge arm not connected to the inductor are conducted or disconnected based on the polarity of the input AC power supply.

19. The upper bridge switch transistor and the lower bridge switch transistor in the first bridge arm or the second bridge arm are connected or disconnected based on the polarity of the input AC power supply. The steps include determining the zero-crossing point of the input AC power supply, The control method according to claim 18, comprising the step of controlling the conduction or disconnection of the upper bridge switch transistor and the lower bridge switch transistor at the zero-crossing point.

20. The step of obtaining the rotational speed of the compressor is: The control method according to claim 16 or 17, further comprising the step of detecting the rotational speed of the compressor using a rotational speed sensor.

21. The step of obtaining the rotational speed of the compressor is: The control method according to claim 16 or 17, further comprising the steps of observing the rotor position of the compressor using a magnetic flux observer and obtaining the rotational speed of the compressor.

22. A computer-readable storage medium that stores a control program for a PFC circuit in a refrigeration system, and when the program is executed by a processor, enables the control method for a PFC circuit in a refrigeration system according to any one of claims 14 to 21.

23. A controller comprising memory, a processor, and a control program for a PFC circuit in a refrigeration system stored in the memory and operable by the processor, wherein when the processor executes the program, a controller realizes the control method for a PFC circuit in a refrigeration system according to any one of claims 14 to 21.

24. A PFC circuit including synchronous rectification mode and high-frequency PFC mode, Compressor and A refrigeration system comprising: 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 based on the torque of the compressor.

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