Power supply circuit and refrigeration device

Abstract

Provided in the present application are a power supply circuit and a refrigeration device. The power supply circuit comprises a Swiss conversion circuit (10), a first voltage measurement circuit (20), a second voltage measurement circuit (30) and a control circuit (40), wherein the Swiss conversion circuit (10) converts an alternating-current voltage into a direct-current voltage and outputs same to a load; the first voltage measurement circuit (20) measures the alternating-current voltage input to the Swiss conversion circuit (10), and outputs a first voltage measurement signal; the second voltage measurement circuit (30) measures the direct-current voltage output by the Swiss conversion circuit (10), and outputs a second voltage measurement signal; when a voltage value of a switching transistor in the Swiss conversion circuit (10) is within a preset voltage range, on the basis of the first voltage measurement signal and the second voltage measurement signal, the control circuit (40) controls the operation of the switching transistor in the Swiss conversion circuit (10); and when the voltage value of the switching transistor in the Swiss conversion circuit (10) is beyond the preset voltage range, on the basis of the first voltage measurement signal, the control circuit (40) controls the operation of the switching transistor in the Swiss conversion circuit (10).

Description

Power supply circuit and refrigeration equipment

[0001] Related applications

[0002] The present application claims priority to Chinese Patent Application No. 202411364418.0, filed on September 27, 2024, the entire contents of which are incorporated herein by reference.

[0003] TECHNICAL FIELD

[0004] The present application relates to the technical field of refrigeration equipment, in particular to a power supply circuit and a refrigeration equipment. BACKGROUND

[0005] The existing three-phase PFC rectifier has the advantages of large output power, high power factor, small total harmonic distortion, etc., can automatically adjust the input current of the port, thereby realizing current balance, minimizing load current pulse, improving the utilization efficiency of physical load on power, reducing energy waste, and has more extensive application value in large-capacity and high-performance rectification applications. In the air conditioner with three-phase Swiss inverter circuit topology application, when the input voltage is 380V, the voltage stress of the single switch tube in the Swiss inverter middle line injection loop will affect the selection of the device, which will greatly increase the cost of the electric control. The selection of the existing switch tube is a high-voltage IGBT switch tube with a withstand voltage exceeding 800V, which has low device packaging integration and high price, which is not conducive to the miniaturization and cost control of the electric control of the three-phase Swiss PFC air conditioner. At the same time, the three-phase PFC rectifier has the problems of complex main circuit structure and complex control method in actual application. SUMMARY

[0006] The main purpose of the present application is to provide a power supply circuit and a refrigeration equipment, which aims to ensure the reliability and stability of the power supply circuit while improving the efficiency and reducing the cost of the power supply circuit.

[0007] The application provides a power supply circuit, which comprises a Swiss conversion circuit, a first voltage detection circuit, a second voltage detection circuit and a control circuit.

[0008] In an embodiment, the control circuit is specifically configured to obtain the voltage value of the switch tube in the Swiss conversion circuit according to the first voltage detection signal, control the switch tube in the Swiss conversion circuit to be turned on according to the first preset duty ratio when the voltage value of the switch tube in the Swiss conversion circuit is within the preset voltage range, and control the switch tube in the Swiss conversion circuit to be turned on according to the second preset duty ratio and / or be turned off when the voltage value of the switch tube in the Swiss conversion circuit exceeds the preset voltage range.

[0009] In an embodiment, the control circuit comprises a drive circuit, a controller and a control terminal.

[0010] In an embodiment, the Swiss conversion circuit comprises a filter circuit, a rectifier circuit, a switching circuit and an adjusting circuit.

[0011] In an embodiment, the Swiss conversion circuit has a first connection end, a second connection end, and a neutral end for accessing an alternating voltage, the neutral end including a first neutral end, a second neutral end, and a third neutral end; a first input end of the switch circuit is connected to the first connection end, a second input end of the switch circuit is connected to the first neutral end, a third input end of the switch circuit is connected to the second neutral end, a fourth input end of the switch circuit is connected to the third neutral end, and a fifth input end of the switch circuit is connected to the second connection end; a first output end, a second output end, and a third output end of the switch circuit are used to connect a load, and a first controlled end, a second controlled end, a third controlled end, a fourth controlled end, and a fifth controlled end of the switch circuit are connected to a control end of the drive circuit.

[0012] In an embodiment, the switch circuit includes a first high-frequency switch tube, a second high-frequency switch tube, a first switch group, a second switch group, and a third switch group; an input end of the first high-frequency switch tube is a first input end of the switch circuit, an input end of the first switch group is a first neutral end of the switch circuit, an input end of the second switch group is a second neutral end of the switch circuit, an input end of the third switch group is a third neutral end of the switch circuit, and an input end of the second high-frequency switch tube is a fifth input end of the switch circuit; an output end of the first high-frequency switch tube is a first output end of the switch circuit, a common end between an output end of the first switch group, an output end of the second switch group, and an output end of the third switch group is a second output end of the switch circuit, and an output end of the second high-frequency switch tube is a third output end of the switch circuit; a controlled end of the first high-frequency switch tube is a first controlled end of the switch circuit, a controlled end of the first switch group is a second controlled end of the switch circuit, a controlled end of the second switch group is a third controlled end of the switch circuit, a controlled end of the third switch group is a fourth controlled end of the switch circuit, and a controlled end of the second high-frequency switch tube is a fifth controlled end of the switch circuit.

[0013] In an embodiment, the controller is configured to acquire voltage values of the first switch group, the second switch group, and the third switch group according to the first voltage detection signal, and to control the drive circuit to turn off the first switch group, the second switch group, and the third switch group when the voltage value of any one of the first switch group, the second switch group, and the third switch group exceeds a preset voltage range.

[0014] In an embodiment, the adjustment circuit includes a reverse diode connected in series between the switch circuit and the load; the reverse diode is configured to change from a conduction state to an off state when a direction of a current output from the switch circuit to the load changes.

[0015] In an embodiment, the filter circuit includes a bus film capacitor connected in parallel with the neutral end of the Swiss conversion circuit; the film capacitor is configured to perform filtering processing on the alternating voltage of the neutral end.

[0016] In an embodiment, the rectifier circuit comprises: a rectifier diode connected in series between the bus film capacitor and the switching circuit; the rectifier diode is used to rectify the alternating voltage of the bus film capacitor into direct current voltage.

[0017] The application also provides a refrigeration equipment comprising the power supply circuit.

[0018] In an embodiment, the refrigeration equipment is an air conditioner.

[0019] The application provides a power supply circuit and a refrigeration equipment. The power supply circuit comprises a Swiss conversion circuit, a first voltage detection circuit, a second voltage detection circuit and a control circuit. The Swiss conversion circuit converts an alternating voltage into a direct current voltage and outputs the direct current voltage to a load; the voltage detection circuit detects the alternating voltage input to the Swiss conversion circuit and outputs a first voltage detection signal; the second voltage detection circuit detects the direct current voltage output by the Swiss conversion circuit and outputs a second voltage detection signal; when the voltage value of a switch tube in the Swiss conversion circuit is in a preset voltage range, the control circuit drives the switch tube in the Swiss conversion circuit to work according to the first voltage detection signal and the second voltage detection signal; when the voltage value of the switch tube in the Swiss conversion circuit exceeds the preset voltage range, the control circuit drives the switch tube in the Swiss conversion circuit to work according to the first voltage detection signal. The application sets the switch tube in the power supply circuit as a low-voltage switch tube, and when the voltage stress of the low-voltage switch tube reaches its threshold value, the duty ratio and the switching condition of the switch tube are adjusted in time to reduce the burden of the switch tube with excessively high voltage stress, avoid damaging the switch tube and other circuit modules, ensure the reliability and stability of the three-phase Swiss PFC circuit, and improve the efficiency and reduce the cost of the power supply circuit. BRIEF DESCRIPTION OF DRAWINGS

[0020] In order to more clearly illustrate the technical solutions in the embodiments of the application or the related art, the following will briefly introduce the drawings needed to be used in the embodiment or related art description. Obviously, the drawings in the following description are only some embodiments of the application, and for those skilled in the art, other drawings can also be obtained from the structures shown in the drawings without creative labor.

[0021] FIG. 1 is a circuit flow diagram of the power supply circuit of the application;

[0022] FIG. 2 is a circuit structure diagram of the power supply circuit of the application;

[0023] FIG. 3 is a control signal and input / output schematic diagram of a conventional three-phase Swiss PFC circuit;

[0024] FIG. 4 is a control signal and input / output schematic diagram of the Swiss conversion circuit of the application.

[0025] The implementation, functional features and advantages of the present application will be further described with reference to the embodiments and the accompanying drawings. Embodiments of the present application

[0026] The technical solutions in the embodiments of the present application will be clearly and completely described with reference to the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work fall within the scope of protection of the present application.

[0027] It should be noted that all directional indications, such as up, down, left, right, front, back, etc., in the embodiments of the present application are only used to explain the relative position relationship, movement condition, etc. between components in a certain posture (as shown in the drawings), and if the certain posture changes, the directional indications also change accordingly.

[0028] In the present application, unless otherwise explicitly specified and limited, the terms “connection”, “fixation” and the like should be understood in a broad sense, for example, “fixation” can be fixed connection, or detachable connection, or integral; can be mechanical connection, or electrical connection; can be direct connection, or indirect connection through an intermediate medium; can be internal connection of two elements or interaction relationship between two elements, unless otherwise explicitly limited. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0029] In addition, the description such as “first”, “second” and the like in the present application is only for the purpose of description, and cannot be understood as indicating or implying the relative importance of the indicated technical features or implicitly indicating the number of the indicated technical features. Therefore, the features limited by “first”, “second” can explicitly or implicitly include at least one of the features. In addition, the technical solutions of each embodiment can be combined with each other, but it must be based on the fact that the technical solutions can be realized by those skilled in the art, and when the combination of technical solutions appears contradictory or unachievable, it should be considered that the combination of technical solutions does not exist, and is not within the scope of protection claimed by the present application.

[0030] It can be understood that the existing three-phase PFC rectifier has the advantages of large output power, high power factor, small total harmonic distortion, etc., can automatically adjust the input current of the port, thereby realizing current balance, minimizing the load current pulse, improving the utilization efficiency of physical load to power, reducing energy waste, and having more extensive application value in large-capacity and high-performance rectification applications. In the air conditioner with a three-phase Swiss PFC circuit topology, when the input voltage is 380V, the voltage stress of the single switch tube in the middle line injection circuit of the Swiss frequency converter will affect the selection of the device, which will greatly increase the cost of the electric control. The selection of the existing switch tube is a high-voltage IGBT switch tube with a withstand voltage exceeding 800V, which has low device packaging integration and high price, which is not conducive to the miniaturization and cost control of the electric control of the three-phase Swiss PFC air conditioner. At the same time, the three-phase PFC rectifier has problems such as complex main circuit structure and complex control method in actual application.

[0031] In order to ensure the reliability and stability of the power supply circuit while improving the efficiency and reducing the cost of the power supply circuit, the present application provides a power supply circuit, referring to FIG. 1, the power supply circuit comprises:

[0032] The Swiss conversion circuit 10 is used for converting alternating voltage into direct current voltage and outputting to the load;

[0033] The first voltage detection circuit 20 is connected between the Swiss conversion circuit 10, and the first voltage detection circuit 20 is used for detecting the alternating voltage input into the Swiss conversion circuit 10 and outputting a first voltage detection signal;

[0034] The second voltage detection circuit 30 is connected to the output end of the Swiss conversion circuit 10, and the second voltage detection circuit 30 is used for detecting the direct current voltage output by the Swiss conversion circuit 10 and outputting a second voltage detection signal;

[0035] The control circuit 40 is connected with the Swiss conversion circuit 10 and the voltage detection circuit respectively; the control circuit 40 is used for driving the switch tube in the Swiss conversion circuit 10 to work according to the first voltage detection signal and the second voltage detection signal when the voltage value of the switch tube in the Swiss conversion circuit 10 is in the preset voltage range;

[0036] When the voltage value of the switch tube in the Swiss conversion circuit 10 exceeds the preset voltage range, the control circuit 40 is used for driving the switch tube in the Swiss conversion circuit 10 to work according to the first voltage detection signal.

[0037] It can be understood that, with reference to the control signal and input and output schematic diagram of the conventional three-phase Swiss PFC circuit of FIG. 3, the existing three-phase Swiss PFC circuit control usually operates in a double closed-loop mode to ensure stable operation of the bus voltage and current. The maximum voltage stress between each pair of back-to-back switch tubes in the three-phase Swiss PFC circuit occurs at the position where the absolute value of each phase voltage is maximum, and the voltage size is 1.5 times the amplitude of the phase voltage. However, in actual operation, the maximum voltage stress between each pair of back-to-back switch tubes in the three-phase Swiss PFC circuit should also consider the bus voltage fluctuation and the bus inductance glitch when the switch tube is turned on and turned off. In order to further reduce the device cost of the entire three-phase Swiss PFC circuit and improve the reliability of the system, when the voltage stress of the switch tube reaches its threshold value, the present application proposes a power supply circuit, which sets the voltage stress value expected by the technician as the voltage threshold Vset in advance. When the pressure of the switch tube in the Swiss conversion circuit is within the voltage threshold Vset, a double closed-loop mode control is adopted; when the pressure of the switch tube in the Swiss conversion circuit exceeds the voltage threshold Vset, a voltage regulation mode control is adopted to adjust the switching state of each switch tube in the Swiss conversion circuit, greatly reducing the absolute value of the maximum voltage stress that the switch tube can withstand, and at the same time adjusting the switching signal of the bus switch tube to keep the control loop stable.

[0038] It needs to be understood that, compared with low-voltage switch tubes, medium and high-voltage switch tubes can withstand higher voltage. In order to ensure safe and reliable operation, the breakdown voltage of the switch tube must be higher than the maximum working voltage in the application, and usually a certain safety margin is also required. In the air conditioner using the three-phase Swiss PFC circuit topology, 380V belongs to the medium and high voltage range, and the input voltage of 380V may need to select a switch tube with a voltage of 600V or even higher. High-voltage switch tubes usually have larger chip area and more complex structure, resulting in rising price cost. Therefore, when using high-voltage switch tubes with a voltage exceeding 800V, the price is higher than that of switch tubes used in 220V or lower voltage systems. In this way, high-voltage switch tubes not only have low integration, but also have high price, which is not conducive to the miniaturization and cost control of the electric control of the air conditioner. In order to solve the problems of high cost and low integration of switch tubes in the case of high-voltage input, the present application sets the switch tube in the power supply circuit as a low-voltage switch tube, and adjusts the duty ratio and switching condition of the switch tube in time when the voltage stress of the low-voltage switch tube reaches its threshold value, to reduce the burden of the switch tube with excessive voltage stress, avoid damaging the switch tube and other circuit modules, ensure the reliability and stability of the three-phase Swiss PFC circuit, improve the efficiency of the power supply circuit, and reduce the cost of the power supply circuit.

[0039] In addition, the voltage stress of the switch tube is usually the highest during the switching operation, especially at the moment of switching operation, due to the inductance, capacitance and parasitic effects in the power supply circuit, an excessively high voltage stress can be generated, which can cause damage to the switch tube and even damage to other circuit modules, thereby affecting the normal operation of the circuit module. In the embodiment, a voltage threshold Vset is provided, when the voltage stress value of the switch tube in the power supply circuit is within the range of the voltage threshold Vset, the Swiss conversion circuit 10 operates in a double closed loop mode; when the voltage threshold Vset of the switch tube in the power supply circuit, that is, the pressure borne by the switch tube exceeds the voltage threshold Vset, the Swiss conversion circuit 10 operates in a voltage regulation mode to adjust the switching state of each switch tube in the power supply circuit topology, greatly reducing the absolute value of the maximum voltage stress that can be borne by the switch tube, and at the same time the switching signal of the switch tube makes the control loop stable.

[0040] In actual application, when the control circuit 40 detects that the voltage stress of the switch tube in the Swiss conversion circuit 10 is within the range of the voltage threshold Vset, the Swiss conversion circuit 10 operates in a double closed loop mode, which involves a voltage outer loop process and a current inner loop process. In the voltage outer loop process, the second voltage detection circuit 30 outputs the detected direct current voltage to the control circuit 40, the control circuit 40 compares the direct current voltage with the set reference voltage, and obtains an error voltage according to the comparison result, the control circuit 40 performs voltage conversion processing on the error voltage and outputs it as a reference setting value of the current inner loop. In the current inner loop process, the first voltage detection circuit 20 outputs the detected alternating current voltage to the control circuit 40, the control circuit 40 obtains the corresponding actual current after voltage conversion processing of the alternating current voltage, and compares the actual current with the current waveform corresponding to the reference setting value provided by the voltage outer loop, and obtains an error current according to the comparison result. The control circuit 40 outputs a duty cycle for adjusting the switch tube in the Swiss conversion circuit 10 according to the error current, so that the actual current tracks the reference current waveform. For example, when the control circuit 40 determines that the actual current is lower than the reference current according to the error current, the on-time of the switch tube in the Swiss conversion circuit 10 is increased; when the control circuit 40 determines that the actual current is higher than the reference current according to the error current, the on-time of the switch tube in the Swiss conversion circuit 10 is reduced. Thus, the voltage outer loop and the current inner loop jointly act to enable the Swiss conversion circuit 10 to provide stable output voltage while achieving high power factor.

[0041] When the control circuit 40 detects that the voltage stress of the switch tube in the Swiss converter circuit 10 exceeds the voltage threshold Vset range through the first voltage detection circuit 20, the Swiss converter circuit 10 operates in the voltage regulation mode. In the voltage regulation mode, the control circuit 40 can reduce the excessive voltage stress by adjusting the duty cycle of the switch tube of the Swiss converter circuit. For example, the control circuit 40 can increase the duty cycle of other switch tubes to make more current pass through the other switch tubes, thereby reducing the current burden of the switch tube with excessive voltage stress. Thus, by adjusting the duty cycle of the switch tube, the current waveform can be improved to be closer to a sinusoidal wave, and the current harmonic can be reduced. The smoother current waveform helps to reduce the voltage stress of the switch tube during switching. Alternatively, the control circuit 40 can turn off all the switch tubes in the Swiss converter circuit 10 to cap the voltage stress across the switch tube in the Swiss converter circuit 10 at the voltage threshold Vset. Since all the switch tubes are turned off, the current path in the power supply circuit is cut off, and the current flowing through the switch tube is reduced to zero, thereby stopping further voltage stress accumulation and avoiding additional voltage stress due to switching action. For example, taking a three-phase four-wire 380V power supply as an example, theoretically, when the input voltage is below 264V, the maximum voltage that a single pair of switch tubes in the Swiss converter circuit 10 can withstand is 560V. Considering the voltage fluctuation of the bus filter capacitor in the Swiss converter circuit 10, the maximum voltage that the switch tube can withstand may reach 580V. Referring to the control signal and input / output schematic diagram of the Swiss converter circuit in FIG. 4, when the voltage across the switch tube in the Swiss converter circuit 10 reaches the voltage threshold Vset, the control circuit 40 turns off all the switch tubes of the Swiss converter circuit 10 to cap the voltage stress across the switch tube at Vset, thereby ensuring the safe operation of the Swiss converter circuit 10. At the same time, the lower maximum switching stress allows the switch tube of the Swiss converter circuit 10 to select a smaller size when selecting, thereby reducing the cost of the entire power supply circuit topology. Thus, by turning off or limiting the switching action of other switch tubes, further voltage stress increase and potential equipment damage can be prevented.

[0042] The application provides a power supply circuit, which comprises a Swiss conversion circuit 10, a first voltage detection circuit 20, a second voltage detection circuit 30 and a control circuit 40. The input end of the voltage detection circuit is connected between the Swiss conversion circuit 10, the input end of the voltage detection circuit is connected to the output end of the Swiss conversion circuit 10, and the control circuit 40 is connected with the Swiss conversion circuit 10 and the voltage detection circuit respectively. In actual application, the Swiss conversion circuit 10 is used for converting an alternating voltage into a direct voltage and outputting the direct voltage to a load; the voltage detection circuit is used for detecting the alternating voltage input into the Swiss conversion circuit 10 and outputting a first voltage detection signal; the second voltage detection circuit 30 is used for detecting the direct voltage output by the Swiss conversion circuit 10 and outputting a second voltage detection signal; and the control circuit 40 is used for driving the switch tube in the Swiss conversion circuit 10 to work according to the first voltage detection signal and the second voltage detection signal when the voltage value of the switch tube in the Swiss conversion circuit 10 is in a preset voltage range, and driving the switch tube in the Swiss conversion circuit 10 to work according to the first voltage detection signal when the voltage value of the switch tube in the Swiss conversion circuit 10 exceeds the preset voltage range. According to the application, the switch tube in the power supply circuit is set as a low-voltage switch tube, and when the voltage stress of the low-voltage switch tube reaches the threshold value, the duty ratio and the switching condition of the switch tube are adjusted in time, so as to reduce the burden of the switch tube with excessively high voltage stress, avoid damaging the switch tube and other circuit modules, ensure the reliability and stability of the power supply circuit, improve the efficiency of the power supply circuit and reduce the cost of the power supply circuit.

[0043] In an embodiment, referring to FIG. 1, the control circuit 40 is specifically used for acquiring the voltage value of the switch tube in the Swiss conversion circuit 10 according to the first voltage detection signal, controlling the switch tube in the Swiss conversion circuit 10 to be turned on according to a first preset duty ratio when the voltage value of the switch tube in the Swiss conversion circuit 10 is in a preset voltage range, and controlling the switch tube in the Swiss conversion circuit 10 to be turned on according to a second preset duty ratio and / or turned off when the voltage value of the switch tube in the Swiss conversion circuit 10 exceeds the preset voltage range.

[0044] It can be understood that in the embodiment, the preset voltage range is set as the voltage threshold Vset, the control circuit 40 acquires the voltage value of the switch tube in the Swiss conversion circuit 10 through the first voltage detection circuit 20, and detects that the voltage value of the switch tube in the Swiss conversion circuit 10 is in the voltage threshold Vset range, and the control circuit 40 controls the Swiss conversion circuit 10 to operate in the double closed loop mode, so as to control the switch tube in the Swiss conversion circuit 10 to conduct according to the first preset duty ratio through the cooperation of the voltage outer loop and the current inner loop, so that the Swiss conversion circuit 10 can provide stable output voltage while realizing high power factor.

[0045] When the control circuit 40 detects that the voltage value of the switch tube in the Swiss conversion circuit 10 exceeds the voltage threshold Vset range, the control circuit 40 controls the Swiss conversion circuit 10 to operate in the voltage regulation mode, so as to control the driving circuit to drive the switch tube in the Swiss conversion circuit 10 to conduct according to the second preset duty ratio, so as to increase the duty ratio of other switch tubes, so that more current passes through other switch tubes, thereby reducing the current burden of the switch tube with excessively high voltage stress. Or, all the switch tubes in the Swiss conversion circuit 10 are turned off to eliminate the voltage stress of the switch tubes in the Swiss conversion circuit 10 to the voltage threshold Vset, thereby stopping further voltage stress accumulation and avoiding additional voltage stress caused by switching action.

[0046] In an embodiment, with reference to FIG. 2, the control circuit 40 comprises:

[0047] a driving circuit, a control end of the driving circuit being connected with the Swiss conversion circuit 10;

[0048] a controller, a control end of the controller being connected with a controlled end of the driving circuit; the controller is used for controlling the driving circuit to drive the switch tube in the Swiss conversion circuit 10 to work according to the first voltage detection signal and the second voltage detection signal when the voltage value of the switch tube in the Swiss conversion circuit 10 is in the preset voltage range; and the controller is used for controlling the driving circuit to drive the switch tube in the Swiss conversion circuit 10 to work according to the first voltage detection signal when the voltage value of the switch tube in the Swiss conversion circuit 10 exceeds the preset voltage range.

[0049] It can be understood that in the embodiment, the control circuit 40 comprises the driving circuit and the controller. The controller is realized by an MCU, the driving circuit is realized by a PFC driving conversion circuit, the first voltage detection circuit 20 is realized by an alternating voltage detection loop, and the second voltage detection circuit 30 is realized by a direct current voltage detection loop.

[0050] In practical applications, the MCU obtains the voltage value of the switch tube in the Swiss conversion circuit 10 through the alternating voltage detection loop, and detects that the voltage value of the switch tube in the Swiss conversion circuit 10 is in the voltage threshold value Vset range. When the MCU controls the PFC drive conversion circuit to drive the Swiss conversion circuit 10 to operate in a double closed loop mode, the voltage outer loop and the current inner loop jointly act on the Swiss conversion circuit 10 to drive the switch tube in the Swiss conversion circuit 10 to conduct according to the first preset duty ratio, so that the Swiss conversion circuit 10 can provide stable output voltage while realizing high power factor. When the MCU detects that the voltage value of the switch tube in the Swiss conversion circuit 10 exceeds the voltage threshold value Vset range, the MCU controls the PFC drive conversion circuit to drive the Swiss conversion circuit 10 to operate in a voltage regulation mode, so as to control the driving circuit to drive the switch tube in the Swiss conversion circuit 10 to conduct according to the second preset duty ratio, so as to increase the duty ratio of other switch tubes. Let more current pass through other switch tubes, thereby reducing the current burden of the switch tube with too high voltage stress. Alternatively, the PFC drive conversion circuit controls all the switch tubes in the Swiss conversion circuit 10 to be closed, so as to eliminate the voltage stress of the switch tubes in the Swiss conversion circuit 10 at the voltage threshold value Vset, thereby stopping the further accumulation of voltage stress and avoiding the additional voltage stress caused by the switching action.

[0051] In an embodiment, referring to FIG. 2, the Swiss conversion circuit 10 includes a filter circuit 11, a rectifier circuit 12, a switching circuit 13 and a regulation circuit 14.

[0052] The input end of the filter circuit 11 is used to access the alternating voltage, the output end of the filter circuit 11 is connected with the input end of the rectifier circuit 12, the output end of the rectifier circuit 12 is connected with the input end of the switching circuit 13, the output end of the switching circuit 13 is connected with the input end of the regulation circuit 14, and the output end of the regulation circuit 14 is connected with the load.

[0053] It can be understood that in the embodiment, the Swiss conversion circuit 10 is composed of the filter circuit 11, the rectifier circuit 12, the switching circuit 13 and the regulating circuit 14, mainly relying on the switching circuit 13 to improve the power factor of the circuit and reduce the harmonic content of the input current. For example, the filter circuit 11 filters the alternating voltage and outputs it to the rectifier circuit 12, the rectifier circuit 12 rectifies the filtered alternating voltage and outputs a direct current to the switching circuit 13, a high-frequency switch in the switching circuit 13 and the regulating circuit 14 form a Buck structure to realize voltage reduction and rectification. By controlling the switch in the switching circuit 13 through the control algorithm of the control circuit 40, the harmonic current is injected, the power factor of the circuit is greatly improved and the input current harmonic is reduced, and by controlling the high-frequency switch in the switching circuit 13 through the control algorithm of the control circuit 40, the circuit outputs stable and low-ripple voltage.

[0054] In an embodiment, with reference to FIGS. 1 and 2, the Swiss conversion circuit 10 has a first connection end, a second connection end and a neutral end for connecting an alternating voltage, the neutral end including a first neutral end, a second neutral end and a third neutral end;

[0055] The first input end of the switching circuit 13 is connected with the first connection end, the second input end of the switching circuit 13 is connected with the first neutral end, the third input end of the switching circuit 13 is connected with the second neutral end, the fourth input end of the switching circuit 13 is connected with the third neutral end, and the fifth input end of the switching circuit 13 is connected with the second connection end;

[0056] The first output end, the second output end and the third output end of the switching circuit 13 are used to connect a load, and the first controlled end, the second controlled end, the third controlled end, the fourth controlled end and the fifth controlled end of the switching circuit 13 are connected with the control end of the driving circuit.

[0057] It can be understood that in the embodiment, the switching circuit 13 is connected with the alternating voltage through the neutral end of the Swiss conversion circuit 10, the filter circuit 11 is arranged in parallel on the connection path between the switching circuit 13 and the alternating voltage; the rectifier circuit 12 is arranged in series on the connection path between the switching circuit 13 and the alternating voltage through the first connection end and the second connection end of the Swiss conversion circuit 10; and the control circuit 40 is connected with the controlled end of the switching circuit 13.

[0058] In practical application, the filter circuit 11 outputs the filtered AC voltage to the rectifier circuit 12, the rectifier circuit 12 outputs the rectified DC voltage to the switching circuit 13, the control circuit 40 outputs the control signal to adjust the switching state of the switching tube in the switching circuit 13 to improve the power factor of the circuit and reduce the harmonic content of the input current. The switching circuit 13 outputs the DC voltage to the regulating circuit 14, the regulating circuit 14 outputs the stable DC voltage to the load after voltage regulation, thereby realizing the function of converting AC voltage into DC voltage and outputting to the load.

[0059] In an embodiment, referring to FIG. 1 and FIG. 2, the switching circuit 13 includes a first high-frequency switching tube, a second high-frequency switching tube, a first switching group, a second switching group, and a third switching group.

[0060] The input end of the first high-frequency switching tube is the first input end of the switching circuit 13, the input end of the first switching group is the first neutral end of the switching circuit 13, the input end of the second switching group is the second neutral end of the switching circuit 13, the input end of the third switching group is the third neutral end of the switching circuit 13, and the input end of the second high-frequency switching tube is the fifth input end of the switching circuit 13.

[0061] The output end of the first high-frequency switching tube is the first output end of the switching circuit 13, the common end between the output end of the first switching group, the output end of the second switching group, and the output end of the third switching group is the second output end of the switching circuit 13, and the output end of the second high-frequency switching tube is the third output end of the switching circuit 13.

[0062] The controlled end of the first high-frequency switching tube is the first controlled end of the switching circuit 13, the controlled end of the first switching group is the second controlled end of the switching circuit 13, the controlled end of the second switching group is the third controlled end of the switching circuit 13, the controlled end of the third switching group is the fourth controlled end of the switching circuit 13, and the controlled end of the second high-frequency switching tube is the fifth controlled end of the switching circuit 13.

[0063] It can be understood that in the embodiment, the alternating voltage includes three-phase alternating voltage, which is Ua, Ub and Uc respectively; the filter circuit 11 includes three filter capacitors, which are Ca, Cb and Cc respectively; the rectifier circuit 12 includes six rectifier diodes, which are D1, D2, D3, D4, D5 and D6 respectively; the switching circuit 13 includes three groups of switching groups and two high-frequency switching tubes, the three groups of switching groups are S1, S2 and S3 respectively, and the two high-frequency switching tubes are T+ and T- respectively. Among them, each group of switching groups is realized by a pair of back-to-back IGBT (Insulated Gate Bipolar Transistor) switching tubes, which is used to improve the power factor of the circuit and reduce the harmonic content of the input current; the adjusting circuit 14 includes two reverse diodes, which are DF+ and DF- respectively. In addition, the power supply circuit further includes three high-frequency PFC inductors La, Lb and Lc, two DC filter inductors L1, L2 and one bus film capacitor Co. The Buck structure is formed by T+, T-, L1, L2 and Co to realize voltage reduction output and rectification. The switching tubes T+ and T- are controlled by a specific algorithm to output stable and low-ripple voltage. It should be pointed out that the connection point between the negative electrode of D1 and the negative electrode of D3 is the first connection end of the Swiss conversion circuit 10, the connection point between the positive electrode of D4 and the positive electrode of D6 is the second connection end of the Swiss conversion circuit 10; the connection point between La and S1 is the first neutral end of the Swiss conversion circuit 10, the connection point between Lb and S2 is the second neutral end of the Swiss conversion circuit 10, and the connection point between Lc and S3 is the third neutral end of the Swiss conversion circuit 10.

[0064] In an embodiment, referring to FIG. 2, the controller is configured to acquire voltage values of the first switching group, the second switching group and the third switching group according to the first voltage detection signal respectively, and control the driving circuit to turn off the first switching group, the second switching group and the third switching group when the voltage value of any one of the first switching group, the second switching group and the third switching group exceeds the preset voltage range.

[0065] It can be understood that the first voltage detection circuit 20 is configured to detect the three-phase alternating voltage Ua, Ub and Uc, and the second voltage detection circuit 30 is configured to detect the DC voltage Udc flowing through the bus film capacitor Co. In the embodiment, the control circuit 40 acquires the voltage on both sides of S1, S2 and S3 according to Ua, Ub and Uc respectively, controls the driving circuit to turn off all switching groups of the neutral end of the Swiss conversion circuit 10, that is, to turn off S1, S2 and S3, when the voltage on both sides of any one of S1, S2 and S3 exceeds the voltage threshold Vset, thereby preventing further voltage stress increase and potential equipment damage by turning off or limiting the switching action of other switching tubes; controls the switching circuit 13 to operate in a double closed-loop mode when the voltage on both sides of S1, S2 and S3 is within the voltage threshold Vset range.

[0066] In another embodiment, the control circuit 40 obtains the voltage on both sides of S1, S2 and S3 according to Ua, Ub and Uc respectively, and controls the switching circuit 13 to operate in the voltage regulation mode to regulate the switching state and duty cycle of S1, S2, S3, T+ and T- when it is determined that the voltage on both sides of any one of S1, S2 and S3 exceeds the voltage threshold Vset, and controls the switching circuit 13 to operate in the double closed loop mode when it is determined that the voltage on both sides of S1, S2 and S3 is within the voltage threshold Vset.

[0067] In an embodiment, referring to FIG. 2, the adjustment circuit 14 comprises:

[0068] a reverse diode connected in series between the switching circuit 13 and the load; the reverse diode is used to change from the conduction state to the off state when the direction of the current output from the switching circuit 13 to the load changes.

[0069] It can be understood that in the present embodiment, the adjustment circuit 14 comprises two reverse diodes, namely DF+ and DF-, which provide reverse current protection in the power supply circuit. When the direction of the current output from the switching circuit 13 to the load changes, the reverse diode will automatically turn off, thereby protecting other circuits in the power supply circuit from reverse voltage.

[0070] In an embodiment, referring to FIG. 2, the filter circuit 11 comprises:

[0071] a bus film capacitor connected in parallel with the neutral line end of the Swiss conversion circuit 10; the film capacitor is used to filter the alternating voltage of the neutral line end.

[0072] It can be understood that in the present embodiment, the filter circuit 11 comprises three filter capacitors, namely Ca, Cb and Cc, which are all implemented by bus film capacitors. Ca, Cb and Cc are connected in parallel with the first neutral line end, the second neutral line end and the third neutral line end respectively, and the three filter capacitors are used to filter the alternating voltages Ua, Ub and Uc and output them to the rectifier circuit 12 through the first neutral line end, the second neutral line end and the third neutral line end.

[0073] In an embodiment, referring to FIG. 2, the rectifier circuit 12 comprises:

[0074] a rectifier diode connected in series between the bus film capacitor and the switching circuit 13; the rectifier diode is used to rectify the alternating voltage of the bus film capacitor into direct current voltage.

[0075] It can be understood that in the embodiment, the rectifier circuit 12 includes six rectifier diodes, namely D1, D2, D3, D4, D5 and D6. The connection point between the negative electrode of D1 and the negative electrode of D3 is the first connection end of the Swiss conversion circuit 10, the connection point between the positive electrode of D4 and the positive electrode of D6 is the second connection end of the Swiss conversion circuit 10, and the six rectifier diodes are used to rectify the filtered alternating voltages Ua, Ub and Uc and output direct current voltages to S1, S2 and S3, T+ and T-.

[0076] The application also provides a refrigeration equipment, which comprises the power supply circuit of the above embodiment. The specific circuit structure of the refrigeration equipment is referred to the above embodiment. Since the refrigeration equipment adopts all the technical solutions of the above embodiments, it at least has all the beneficial effects brought by the technical solutions of the above embodiments, which will not be repeated here.

[0077] In an embodiment, the refrigeration equipment is an air conditioner.

[0078] It can be understood that when the power supply circuit is applied to an air conditioner, it can solve the problems of high cost and low integration of the switching tube of the air conditioner under high voltage input. Specifically, the power supply circuit sets the switching tube as a low-voltage switching tube, and timely adjusts the duty cycle and switching condition of the switching tube when the voltage stress of the low-voltage switching tube reaches its threshold value, so as to reduce the burden of the switching tube with excessively high voltage stress and avoid damaging the switching tube and other circuit modules. Since the price of the low-voltage switching tube is relatively low compared with the price of the high-voltage switching tube, the embodiment not only ensures the reliability and stability of the air conditioner, but also improves the efficiency and reduces the cost of the air conditioner.

[0079] The above is only an embodiment of the application, and does not limit the patent scope of the application. Any equivalent structural transformation, direct / indirect application in other related technical fields based on the inventive concept of the application and the content of the specification and drawings are included in the patent protection scope of the application.

Claims

1. A power supply circuit, wherein, The power supply circuit comprises: a Swiss conversion circuit for converting an alternating voltage into a direct voltage output to a load; a first voltage detection circuit, an input end of the voltage detection circuit being connected between the Swiss conversion circuits, the voltage detection circuit being configured to detect the alternating voltage input to the Swiss conversion circuit and output a first voltage detection signal; a second voltage detection circuit, an input end of the voltage detection circuit being connected to an output end of the Swiss conversion circuit, the second voltage detection circuit being configured to detect the direct voltage output by the Swiss conversion circuit and output a second voltage detection signal; a control circuit, the control circuit being connected to the Swiss conversion circuit and the voltage detection circuits respectively, the control circuit being configured to drive the switch tube in the Swiss conversion circuit to work according to the first voltage detection signal and the second voltage detection signal when the voltage value of the switch tube in the Swiss conversion circuit is within a preset voltage range; and the control circuit being configured to drive the switch tube in the Swiss conversion circuit to work according to the first voltage detection signal when the voltage value of the switch tube in the Swiss conversion circuit exceeds the preset voltage range. The control circuit is specifically configured to obtain the voltage value of the switch tube in the Swiss conversion circuit according to the first voltage detection signal, control the switch tube in the Swiss conversion circuit to be turned on according to a first preset duty cycle when the voltage value of the switch tube in the Swiss conversion circuit is within the preset voltage range, control the switch tube in the Swiss conversion circuit to be turned on according to a second preset duty cycle when the voltage value of the switch tube in the Swiss conversion circuit exceeds the preset voltage range, and / or turn off the switch tube in the Swiss conversion circuit when the voltage value of the switch tube in the Swiss conversion circuit exceeds the preset voltage range.

2. The power supply circuit of claim 1, wherein, The control circuit comprises:

3. The power supply circuit of claim 1 or 2, wherein, a drive circuit, a control end of the drive circuit being connected to the Swiss conversion circuit; a controller, a control end of the controller being connected to a controlled end of the drive circuit, the controller being configured to control the drive circuit to drive the switch tube in the Swiss conversion circuit to work according to the first voltage detection signal and the second voltage detection signal when the voltage value of the switch tube in the Swiss conversion circuit is within a preset voltage range, and control the drive circuit to drive the switch tube in the Swiss conversion circuit to work according to the first voltage detection signal when the voltage value of the switch tube in the Swiss conversion circuit exceeds the preset voltage range. The Swiss conversion circuit comprises a filter circuit, a rectifier circuit, a switch circuit and a regulating circuit; 4. The power supply circuit of claim 3, wherein, an input end of the filter circuit is configured to access the alternating voltage, an output end of the filter circuit is connected to an input end of the rectifier circuit, an output end of the rectifier circuit is connected to an input end of the switch circuit, an output end of the switch circuit is connected to an input end of the regulating circuit, and an output end of the regulating circuit is connected to the load. ​ 5. The power supply circuit of claim 4, wherein, The Swiss conversion circuit has a first connection end, a second connection end, and a neutral end for accessing the alternating voltage, the neutral end including a first neutral end, a second neutral end, and a third neutral end; The first input end of the switch circuit is connected with the first connection end, the second input end of the switch circuit is connected with the first neutral end, the third input end of the switch circuit is connected with the second neutral end, the fourth input end of the switch circuit is connected with the third neutral end, and the fifth input end of the switch circuit is connected with the second connection end; The first output end, the second output end, and the third output end of the switch circuit are used for connecting the load, and the first controlled end, the second controlled end, the third controlled end, the fourth controlled end, and the fifth controlled end of the switch circuit are connected with the control end of the drive circuit.

6. The power supply circuit of claim 5, wherein, The switch circuit includes a first high-frequency switch tube, a second high-frequency switch tube, a first switch group, a second switch group, and a third switch group; The input end of the first high-frequency switch tube is the first input end of the switch circuit, the input end of the first switch group is the first neutral end of the switch circuit, the input end of the second switch group is the second neutral end of the switch circuit, the input end of the third switch group is the third neutral end of the switch circuit, and the input end of the second high-frequency switch tube is the fifth input end of the switch circuit; The output end of the first high-frequency switch tube is the first output end of the switch circuit, the common end between the output end of the first switch group, the output end of the second switch group, and the output end of the third switch group is the second output end of the switch circuit, and the output end of the second high-frequency switch tube is the third output end of the switch circuit; The controlled end of the first high-frequency switch tube is the first controlled end of the switch circuit, the controlled end of the first switch group is the second controlled end of the switch circuit, the controlled end of the second switch group is the third controlled end of the switch circuit, the controlled end of the third switch group is the fourth controlled end of the switch circuit, and the controlled end of the second high-frequency switch tube is the fifth controlled end of the switch circuit.

7. The power supply circuit of claim 6, wherein, The controller is used for acquiring voltage values of the first switch group, the second switch group, and the third switch group according to the first voltage detection signal respectively, and controlling the drive circuit to close the first switch group, the second switch group, and the third switch group when the voltage value of any one of the first switch group, the second switch group, and the third switch group exceeds a preset voltage range.

8. The power supply circuit of any one of claims 4 to 7, wherein, The adjustment circuit includes: A reverse diode connected in series between the switch circuit and the load, and used for changing from a conduction state to an off state when the direction of the current output from the switch circuit to the load changes.

9. The power supply circuit of any one of claims 5 to 8, wherein, The filter circuit includes: A bus film capacitor connected in parallel with the neutral end of the Swiss conversion circuit, and used for filtering the alternating voltage of the neutral end.

10. The power supply circuit of claim 9, wherein, The rectifier circuit includes: A rectifier diode is connected in series between the busbar film capacitor and the switching circuit; the rectifier diode is used to rectify the alternating voltage of the busbar film capacitor into direct current voltage.

11. A refrigeration appliance, wherein, The refrigeration device comprises the power supply circuit according to any one of claims 1 to 10.

12. The refrigeration appliance of claim 11, wherein, The refrigeration device is an air conditioner.

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