Power device protection circuit and method, refrigeration equipment and storage medium

Abstract

The invention relates to a power device protection circuit and method, refrigeration equipment and a storage medium, in the power device protection circuit, one end of a resistor R1 is connected with a power supply, the other end of the resistor R1 is sequentially connected with one end of a resistor R2 and one end of a resistor R3 in series, the other end of the resistor R3 is grounded, the first input end of a first comparator is connected with the midpoint of the resistor R1 and the resistor R2, and the second input end of the first comparator is connected with the midpoint of the resistor R2. The second input end of the first comparator is connected with the bus, the output end of the first comparator is connected with the signal output interface, the first input end of the second comparator is connected with the midpoint of the resistor R2 and the resistor R3, the second input end of the second comparator is connected with the bus, and the output end of the second comparator is connected with the signal output interface. The signal output interface is connected with the controller through a diode D1; and the controller is used for controlling the turn-off of the power device according to the signal output by the signal output interface, so that the problem that the power device is not timely protected is solved, and the timeliness of the protection of the power device is improved.

Description

Technical Field

[0001] The present application relates to the field of refrigerators, and in particular to a power device protection circuit, method, refrigeration equipment and storage medium. Background Art

[0002] With the development of frequency conversion technology and the improvement of people's living standards, frequency conversion refrigerators have become the mainstream products on the market due to their energy saving and fast cooling speed. The electric control board of the frequency conversion refrigerator needs to be equipped with relevant hardware protection circuits and software protection strategies to protect the relevant key components and avoid failures caused by various factors.

[0003] Figure 1 is a power device protection circuit diagram of a target variable frequency refrigerator in the existing related technology, such as Figure 1 As shown, the current protection of the power devices of the variable frequency refrigerator is mainly to obtain the bus voltage value by collecting the voltage divider values ​​of the resistors R1, R2, and R3 connected in series in the bus through the DCBUSAD port of the variable frequency MCU. When the bus voltage value exceeds the threshold protection voltage set by the variable frequency MCU, the variable frequency MCU cuts off the variable frequency drive circuit, thereby protecting the power devices in the variable frequency drive circuit.

[0004] However, power devices, whether IPM with built-in IGBT or MOS and high-voltage drive bridge, or IGBT or MOS, all have a key characteristic parameter, collector-to-emitter breakdown voltage (hereinafter referred to as breakdown voltage) Vces. Generally, Vces≤600V. Once the bus voltage exceeds the breakdown voltage of the power device, the power device may open circuit, resulting in the inability of the inverter refrigerator to cool. In severe cases, the power device may short circuit due to excessive instantaneous voltage, causing the inverter refrigerator's electronic control board to catch fire, leading to a safety accident.

[0005] With regard to the problem of untimely protection of power devices in related technologies, no effective solution has been proposed so far. Summary of the invention

[0006] In the present embodiment, a power device protection circuit, method, refrigeration equipment and storage medium are provided to solve the problem of untimely protection of power devices in the related art.

[0007] In a first aspect, a power device protection circuit is provided in this embodiment, including: a resistor R1, a resistor R2, a resistor R3, a first comparator, a second comparator, a signal output interface, a diode D1, and a controller;

[0008] Among them, one end of the resistor R1 is connected to the power supply, the other end of the resistor R1 is connected in series with one end of the resistor R2 and the resistor R3 in sequence, the other end of the resistor R3 is then grounded, the first input end of the first comparator is connected to the midpoint of the resistor R1 and the resistor R2, the second input end of the first comparator is connected to the bus, the output end of the first comparator is connected to the signal output interface, the first input end of the second comparator is connected to the midpoint of the resistor R2 and the resistor R3, the second input end of the second comparator is connected to the bus, the output end of the second comparator is connected to the signal output interface, and the signal output interface is connected to the controller through the diode D1; the controller is used to control the shutdown of the power device according to the signal output interface The signal output interface is connected to the controller.

[0009] In some of the embodiments, the power device protection circuit further includes a resistor R4 and a capacitor C1; the diode D1, the resistor R4, the capacitor C1, the input pin of the controller and the signal output interface form an overvoltage control circuit;

[0010] Among them, the signal output interface is connected to the anode of the diode D1, the cathode of the diode D1 is connected to one end of the resistor R4, the other end of the resistor R4 is connected to one end of the capacitor C1, the other end of the resistor R4 is also connected to the input pin of the controller, and the other end of the capacitor C1 is grounded.

[0011] In some embodiments, the power device protection circuit further includes a resistor R5, a diode D2, a resistor R6, an output pin of a controller, and a resistor R7; the resistor R5, the diode D2, the resistor R6, the resistor R4, an input pin of the controller, and the resistor R7 form an overcurrent control circuit;

[0012] Among them, one end of the resistor R5 is connected to the positive electrode of the diode D2, the negative electrode of the diode D2 is connected to one end of the resistor R6, the other end of the resistor R6 is grounded, the negative electrode of the diode D2 is also connected to one end of the resistor R4, the other end of the resistor R4 is connected to the input pin of the controller, one end of the resistor R7 is connected to the output pin of the controller, the other end of the resistor R7 is grounded, and the other end of the resistor R7 is also connected to the other end of the resistor R5.

[0013] In some of the embodiments, the first comparator and the second comparator are nanoscale voltage comparators.

[0014] In some of the embodiments, the controller is a power device driver chip.

[0015] In a second aspect, a power device protection method is provided in this embodiment, using the power device protection circuit described in the first aspect, including:

[0016] Obtaining a voltage protection range of the bus voltage according to the resistor R1, the resistor R2, the resistor R3, the first comparator, and the second comparator;

[0017] When it is detected that the bus voltage exceeds the voltage protection range, a high level signal is output through the signal output interface;

[0018] A high level signal is input to the controller through the diode D1, so that the controller turns off the power device.

[0019] In some of the embodiments, the power device protection circuit includes an overcurrent control circuit, which detects the current of the power device and determines whether the current is greater than a preset current threshold. If so, the power device is shut down by a controller.

[0020] In a third aspect, a refrigeration device is provided in this embodiment, comprising the power device protection circuit described in the first aspect.

[0021] In a fourth aspect, a variable frequency refrigerator is provided in this embodiment, comprising the power device protection circuit described in the first aspect.

[0022] In a fifth aspect, a storage medium is provided in this embodiment, on which a computer program is stored, and when the program is executed by a processor, the power device protection method described in the second aspect is implemented.

[0023] Compared with the related art, the power device protection circuit provided in this embodiment includes: a resistor R1, a resistor R2, a resistor R3, a first comparator, a second comparator, a signal output interface, a diode D1 and a controller; wherein one end of the resistor R1 is connected to a power supply, the other end of the resistor R1 is connected in series with one end of the resistor R2 and the resistor R3 in sequence, the other end of the resistor R3 is then grounded, the first input end of the first comparator is connected to the midpoint of the resistor R1 and the resistor R2, the second input end of the first comparator is connected to the bus, the output end of the first comparator is connected to the signal output interface, the first input end of the second comparator is connected to the midpoint of the resistor R2 and the resistor R3, the second input end of the second comparator is connected to the bus, the output end of the second comparator is connected to the signal output interface, and the signal output interface is connected to the controller through the diode D1; the controller is used to control the shutdown of the power device according to the signal output interface output signal, solves the problem of untimely protection of the power device, and improves the timeliness of the power device protection.

[0024] Details of one or more embodiments of the present application are set forth in the following drawings and description to make other features, objects, and advantages of the present application more readily apparent. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] The drawings described herein are used to provide a further understanding of the present application and constitute a part of the present application. The illustrative embodiments of the present application and their descriptions are used to explain the present application and do not constitute an improper limitation on the present application. In the drawings:

[0026] Figure 1 It is a power device protection circuit diagram of a target variable frequency refrigerator in the existing related technology.

[0027] Figure 2 It is a hardware structure block diagram of the terminal of the power device protection method of this embodiment.

[0028] Figure 3 4 is a power device protection circuit diagram of this embodiment.

[0029] Figure 4 is a structural diagram of the overvoltage control circuit of the power device protection circuit in this embodiment.

[0030] Figure 5 4 is a structural diagram of an overcurrent control circuit of a power device protection circuit in this embodiment.

[0031] Figure 6 is a flow chart of the power device protection method of this embodiment.

[0032] Figure 7 is a flow chart of another power device protection method of this embodiment. DETAILED DESCRIPTION

[0033] In order to more clearly understand the purpose, technical solutions and advantages of the present application, the present application is described and illustrated below in conjunction with the accompanying drawings and embodiments.

[0034] Unless otherwise defined, the technical terms or scientific terms involved in this application shall have the general meaning understood by people with ordinary skills in the technical field to which this application belongs. The words "one", "a", "a", "the", "these" and the like in this application do not represent quantitative restrictions, and they can be singular or plural. The terms "include", "comprise", "have" and any variants thereof involved in this application are intended to cover non-exclusive inclusions; for example, a process, method and system, product or device comprising a series of steps or modules (units) is not limited to the listed steps or modules (units), but may include unlisted steps or modules (units), or may include other steps or modules (units) inherent to these processes, methods, products or devices. The words "connect", "connected", "coupled" and the like involved in this application are not limited to physical or mechanical connections, but may include electrical connections, whether directly or indirectly. The "multiple" involved in this application refers to two or more. "And / or" describes the association relationship of associated objects, indicating that there can be three relationships. For example, "A and / or B" can mean: A exists alone, A and B exist at the same time, and B exists alone. Usually, the character " / " indicates that the objects associated with each other are in an "or" relationship. The terms "first", "second", "third", etc. involved in this application are only used to distinguish similar objects and do not represent a specific ordering of the objects.

[0035] The method embodiment provided in this embodiment can be executed in a terminal, a computer or a similar computing device. For example, running on a terminal, Figure 2 FIG. 1 is a hardware structure diagram of a terminal of the power device protection method of this embodiment. Figure 2 As shown, the terminal may include one or more ( Figure 2 Only one is shown in the figure) processor 202 and memory 204 for storing data, wherein processor 202 may include but is not limited to a processing device such as a microprocessor MCU or a programmable logic device FPGA. The above terminal may also include a transmission device 206 and an input and output device 208 for communication functions. It can be understood by those skilled in the art that Figure 2 The structure shown is only for illustration and does not limit the structure of the above terminal. Figure 2 More or fewer components as shown, or with Figure 2 Different configurations shown.

[0036] The memory 204 can be used to store computer programs, for example, software programs and modules of application software, such as the computer program corresponding to the power device protection method in this embodiment. The processor 202 executes various functional applications and data processing by running the computer program stored in the memory 204, that is, to implement the above method. The memory 204 may include a high-speed random access memory, and may also include a non-volatile memory, such as one or more magnetic storage devices, flash memory, or other non-volatile solid-state memory. In some examples, the memory 204 may further include a memory remotely arranged relative to the processor 202, and these remote memories may be connected to the terminal via a network. Examples of the above network include, but are not limited to, the Internet, an intranet, a local area network, a mobile communication network, and combinations thereof.

[0037] The transmission device 206 is used to receive or send data via a network. The above network includes a wireless network provided by the communication provider of the terminal. In one example, the transmission device 206 includes a network adapter (Network Interface Controller, referred to as NIC), which can be connected to other network devices through a base station so as to communicate with the Internet. In one example, the transmission device 206 can be a radio frequency (Radio Frequency, referred to as RF) module, which is used to communicate with the Internet wirelessly.

[0038] In this embodiment, a power device protection circuit is provided. Figure 3 : is a power device protection circuit diagram of this embodiment, such as Figure 3 As shown, the power device protection circuit includes: a resistor R1, a resistor R2, a resistor R3, a first comparator A, a second comparator B, a signal output interface 31, a diode D1 and a controller 32, wherein one end of the resistor R1 is connected to a power supply, the other end of the resistor R1 is connected in series with one end of the resistor R2 and the resistor R3 in sequence, the other end of the resistor R3 is then grounded, a first input end 33 of the first comparator A is connected to the midpoint of the resistor R1 and the resistor R2, a second input end 34 of the first comparator A is connected to a bus, an output end 35 of the first comparator A is connected to the signal output interface 31, a first input end 36 of the second comparator B is connected to the midpoint of the resistor R2 and the resistor R3, a second input end 37 of the second comparator B is connected to the bus, an output end 38 of the second comparator B is connected to the signal output interface 31, and the signal output interface 31 is connected to the controller 32 through the diode D1; the controller 32 is used to control the shutdown of the power device according to the signal output from the signal output interface 31.

[0039] Specifically, in the prior art, whether the collected bus voltage exceeds the threshold voltage of the power device protection circuit is analyzed by a software program to determine whether there is an overvoltage. In the process of detecting the voltage by the software program, the conduction process consumes time, and this consumed time often leads to untimely protection of the power device when overvoltage occurs.

[0040] First, the current power device protection solution takes milliseconds. The bus voltage is detected through the AD port of the variable frequency MCU, and the variable frequency MCU sends a signal to shut down the driving power device. However, the time for the variable frequency MCU to collect bus voltage is milliseconds. When the variable frequency MCU collects the voltage protection threshold, it sends a shutdown signal to the power device. This process is also in milliseconds. When the shutdown signal shuts down the power device, if it is shut down through the high-voltage drive bridge, this process will add additional milliseconds. The additional milliseconds will cause the power device to be untimely protected.

[0041] Secondly, in the current power device protection scheme, the power device needs to withstand the sum of two voltages when it is turned off, namely the DC bus voltage Udc and the induced voltage U caused by the stray inductance in the power device circuit. 杂散 The sum of U 杂散 It is not a fixed value. 杂散 =L 杂散 *(di / dt), when the power device is normally turned off, the power device has a short turn-off time (usually below ms), so the current of the power device suddenly drops to 0 in a short time, resulting in a large di / dt value, which in turn causes U 杂散 The value of is also very large, and this value exceeds the breakdown voltage of the power device, causing the power device to fail, and then causing the refrigerator to malfunction. Another situation is when the power device is short-circuited instantly due to circuit abnormality, that is, the current passing through the power device rises from the working current to infinity in a very short time, that is, the current change rate is very large, that is, di / dt is very large and has a larger value than the above situation, resulting in U 杂散 becomes larger, at this time the bus voltage Udc and U 杂散 When this value exceeds the breakdown voltage of the power device, it will cause the power device to fail, thus causing the refrigerator to malfunction. In order to improve the time lost during signal transmission, a hardware comparator is used in this embodiment to collect the bus voltage and output a control signal.

[0042] like Figure 3As shown, resistors R1, R2, and R3 are connected in series in sequence, one end of resistor R1 is connected to the power line, and one end of resistor R3 is grounded, forming a detection circuit for the maximum voltage threshold and the minimum voltage threshold of the comparator. The voltage is collected from the midpoint of resistors R1 and R2 and input to the first input terminal 33 of the first comparator A, that is, the voltage across resistors R2 and R3 is used as the highest voltage threshold, and the voltage is collected from the midpoint of resistors R2 and R3 and input to the first input terminal 36 of the second comparator B, that is, the voltage across resistor R3 is used as the lowest voltage threshold. The second input terminal 34 of the first comparator A is connected to the bus, and the bus voltage is input through the second input terminal 34 of the first comparator A. The bus voltage and the maximum voltage threshold are compared in the first comparator A. If the bus voltage exceeds the maximum voltage threshold, the first comparator A flips the low-level signal into a high-level signal, and transmits the high-level signal to the signal output interface 31 through the output terminal 35 of the first comparator A. The signal output interface 31 then inputs the high-level signal into the controller 32 through the diode D1, and the power device is turned off through the controller 32. When overvoltage occurs, the voltage transmitted to the controller can be reduced according to the voltage drop effect of the forward conduction of the diode D1, thereby protecting the controller and the power device. The second input terminal 37 of the second comparator B is connected to the bus, and the bus voltage is input through the second input terminal 37 of the second comparator B. The bus voltage and the minimum voltage threshold are compared in the second comparator B. If the bus voltage is lower than the minimum voltage threshold, the output terminal 38 of the second comparator B flips the low-level voltage signal into a high-level signal, and transmits the high-level signal to the signal output interface 31 through the output terminal 38 of the second comparator B. The signal output interface 31 then inputs the high-level signal into the controller 32 through the diode D1, and the power device is turned off by the controller 32. Among them, the controller in this embodiment can be an intelligent power module, which combines components such as IGBT, MOS and high-voltage bridge, and directly turns off the power device, or it can also be a power device driver chip, and the power device is turned off by the power device driver chip. Through overvoltage protection of power devices, in the case of overvoltage, a high-level signal is output to shut down the power devices. Diode D1 is set in the protection circuit to reduce the voltage, which can prevent the power devices from being damaged by high voltage breakdown; through undervoltage protection of power devices, power devices can be prevented from being damaged by overheating or overcurrent due to low voltage operation, ensuring the normal operation of power devices.

[0043] In one embodiment, the power device protection circuit further includes a resistor R4 and a capacitor C1; the diode D1, the resistor R4, the capacitor C1, the input pin of the controller and the signal output interface form an overvoltage control circuit;

[0044] Among them, the signal output interface is connected to the anode of the diode D1, the cathode of the diode D1 is connected to one end of the resistor R4, the other end of the resistor R4 is connected to one end of the capacitor C1, the other end of the resistor R4 is also connected to the input pin of the controller, and the other end of the capacitor C1 is grounded.

[0045] Specifically, Figure 4 is a structural diagram of an overvoltage control circuit of a power device protection circuit in this embodiment, such as Figure 4 As shown, the overvoltage control circuit is composed of a signal output interface 31, a diode D1, a resistor R4, a capacitor C1 and an input pin of a controller. The signal output interface 31 is connected to the positive electrode of the diode D1, the negative electrode of the diode D1 is connected to one end of the resistor R4, the other end of the resistor R4 is connected to one end of the capacitor C1, the other end of the resistor R4 is also connected to the input pin 410 of the controller, and the other end of the capacitor C1 is grounded. When the signal output interface 31 outputs a high-level signal, the high-level signal enters the power device driver chip of the controller through the diode D1, the resistor R4, and the input pin 410 of the controller, and the power device is turned off by the power device driver chip. Among them, the resistor R4 and the capacitor C1 form a filter path, which smoothes the rectified DC power supply through the filter path, removes the residual AC component and high-frequency noise, protects the circuit components from the influence of high-frequency interference, improves the quality of the signal, and reduces the malfunction caused by external interference. The unidirectional conduction and voltage reduction effect of diode D1 can reduce the voltage flowing to the overvoltage control circuit to prevent power devices from being damaged by high voltage in overvoltage conditions. It can also prevent the high voltage in the overvoltage control circuit from flowing back in the case of undervoltage of the bus voltage, thereby affecting the normal operation of the power devices.

[0046] In another embodiment, the power device protection circuit further includes a resistor R5, a diode D2, a resistor R6, an output pin of the controller, and a resistor R7; the resistor R5, the diode D2, the resistor R6, the resistor R4, an input pin of the controller, and the resistor R7 form an overcurrent control circuit;

[0047] Among them, one end of the resistor R5 is connected to the positive electrode of the diode D2, the negative electrode of the diode D2 is connected to one end of the resistor R6, the other end of the resistor R6 is grounded, the negative electrode of the diode D2 is also connected to one end of the resistor R4, the other end of the resistor R4 is connected to the input pin of the controller, one end of the resistor R7 is connected to the output pin of the controller, the other end of the resistor R7 is grounded, and the other end of the resistor R7 is also connected to the other end of the resistor R5.

[0048] Specifically, this embodiment also provides an overcurrent protection circuit, which protects the power device by detecting the current on the power device. Figure 4 On the basis of Figure 5 : is a structural diagram of an overcurrent control circuit of a power device protection circuit of this embodiment, such as Figure 5As shown, the overcurrent protection circuit and the overvoltage protection circuit share a channel, one end of the resistor R5 is connected to the positive electrode of the diode D2, the negative electrode of the diode D2 is connected to one end of the resistor R6, the other end of the resistor R6 is grounded, the negative electrode of the diode D2 is also connected to one end of the resistor R4, the other end of the resistor R4 is connected to the input pin 410 of the controller, one end of the resistor R7 is connected to the output pin 51 of the controller, the other end of the resistor R7 is grounded, and the other end of the resistor R7 is also connected to the other end of the resistor R5. By detecting the current on the current control circuit, a comparator is included in the input pin 410 of the controller to compare whether the current on the overcurrent control circuit exceeds a preset current threshold, and when the current threshold is exceeded, the power device is turned off. Among them, the resistor R5 and the resistor R6 are set according to the working current and voltage of the diode D2, and the specific settings are as follows:

[0049] For example, the diode D2 selected in this embodiment is a Schottky diode, model 1SS357. According to the specification of D2, its working range is selected as IF=1mA, VF=0.35V. According to the circuit series principle, the voltage UR5 across the resistor R5 is:

[0050] 0.48V-0.35V=0.13V (1)

[0051] Because IF≤1mA, R5≥0.13V / IF=130Ω. The voltage at the upper end of resistor R6 in the circuit must be equal to the chip's built-in power supply voltage Usc to ensure that the hardware overcurrent protection threshold is consistent with the current solution. Because R5, D2, and R6 are connected in series, the currents passing through the circuit loop devices are equal. According to the chip resistor resistance specification selection table and the resistor R5≥130Ω obtained by the above calculation, R5=150Ω is selected, so:

[0052] Usc / R6=U R5 / R5 (2)

[0053] The calculation results in R6 = 553Ω. Combined with the resistance specification selection table of the chip resistor, R6 is selected as 560Ω. Then R6 is substituted into formula (2) to verify R5 = 151.6Ω. Considering the tolerance of the chip resistor selection and Usc itself, it can be seen that the values ​​of 150Ω and 560Ω for R5 and R6 in this patent solution are appropriate, which is consistent with the hardware overcurrent protection threshold of the current solution and does not affect the overcurrent protection function and protection threshold point of the power device in the current solution.

[0054] The current at the upper end of the collecting resistor R7 is used as the detection current on the current control circuit, and the current collected at this point is input into the input pin 410 of the controller. The comparator in the input pin 410 of the controller compares whether the current is greater than the preset current threshold. If it is greater, the power device is turned off.

[0055] Among them, by setting the diode D2, when overvoltage occurs in the overvoltage control circuit, the high voltage at the diode D1 end is prevented from flowing back to the resistor R5 end, thereby ensuring the normal operation of each component in the overcurrent control circuit. By setting the diode D1 in the overvoltage control circuit, the influence of high voltage or low voltage on the overvoltage control circuit on the overcurrent control circuit can be prevented. Since the diode D1 is set, excessive voltage can be prevented from entering the overcurrent control circuit, and reverse flow can also be prevented when undervoltage occurs, thereby ensuring the normal operation of the components in the current control detection circuit during overvoltage detection.

[0056] In some embodiments, the first comparator and the second comparator are nanometer-scale voltage comparators. The controller is a power device driver chip.

[0057] Specifically, the currently used comparator has a slow transmission speed. In this embodiment, in order to prevent the time loss caused by the transmission process, the first comparator and the second comparator both use nanometer-level voltage comparators to speed up the detection speed and improve the timeliness of power device protection. In addition, in the above embodiments, the controller is a power device driver chip, which receives the signal output from the comparator through the power device driver chip to control the shutdown of the power device. The power device can also be directly encapsulated in the power device driver chip to increase the control speed, further increase the signal processing speed, and improve the efficiency of power device protection.

[0058] In this embodiment, a power device protection method is provided. Figure 6 is a flow chart of the power device protection method of this embodiment, such as Figure 6 As shown, the process includes the following steps:

[0059] Step S601 , obtaining a voltage protection range of the bus voltage according to the resistor R1 , the resistor R2 , the resistor R3 , the first comparator and the second comparator.

[0060] Specifically, through the connection method of the power device protection circuit in the above embodiment, resistors R1, R2, and R3 are connected in series in sequence, one end is connected to the power supply and the other end is grounded, and the maximum voltage threshold and the minimum voltage threshold of the bus voltage are obtained by collecting the first comparator and the second comparator, so as to obtain the voltage protection range, and the bus voltage is detected and judged as overvoltage or undervoltage according to the obtained voltage protection range, wherein the first comparator and the second comparator adopt nanosecond voltage comparators.

[0061] Step S602: when it is detected that the bus voltage exceeds the voltage protection range, a high level signal is output through the signal output interface.

[0062] Specifically, when the detected bus voltage is higher than the maximum voltage threshold or lower than the minimum voltage threshold, the comparator converts the low-level signal into a high-level signal and outputs it through the signal output port.

[0063] Step S603 , inputting a high level signal to the controller through the diode D1 , so that the controller turns off the power device.

[0064] Specifically, when the comparator obtains a high-level signal, the high-level signal is input to the controller through the diode D1, wherein the high-level signal may be caused by overvoltage or undervoltage. The diode D1 can prevent the voltage from flowing back in the overvoltage control circuit, and the diode D1 can also be turned on to reduce the voltage in the case of overvoltage, thereby protecting the power device from breakdown damage. The controller can be a power device driver chip, and when a high-level signal is received, the power device is turned off through the power device driver chip, thereby protecting the power device.

[0065] Through the above steps S601 to S603, the voltage protection range of the bus voltage is obtained according to the resistor R1, the resistor R2, the resistor R3, the first comparator and the second comparator; when the bus voltage is detected to be beyond the voltage protection range, a high level signal is output through the signal output interface; the high level signal is input to the controller through the diode D1, so that the controller turns off the power device. Compared with the prior art that protects the power device by software detection signal, this embodiment detects the collected bus voltage through a nanosecond comparator, converts the software detection signal mode into hardware detection, improves the detection and response speed, and realizes the protection of the power device caused by the bus voltage overvoltage and undervoltage through the power device protection circuit, and realizes more comprehensive protection of the power device. Finally, before the detected high level signal is input to the controller, a diode is set to prevent the voltage reverse flow caused by overvoltage or undervoltage on the basis of realizing the unidirectional conductive characteristics and the forward conduction voltage reduction effect, reduce the voltage size during overvoltage, and improve the timeliness of power device protection.

[0066] In some of the embodiments, the power device protection circuit includes an overcurrent control circuit, which detects the current of the power device and determines whether the current is greater than a preset current threshold. If so, the power device is shut down by a controller.

[0067] Specifically, the present embodiment also includes an overcurrent control circuit, which uses the same controller input pin as the overvoltage control circuit in the above embodiment. By setting a diode D2 on the overcurrent control circuit and a diode D1 on the overvoltage control circuit, it can be ensured that overvoltage and overcurrent detection do not interfere with each other. The overcurrent control circuit can detect the change in the magnitude of the current in the circuit where the power device is located to determine whether the current of the power device exceeds a preset current threshold. When the preset current threshold is exceeded, the power device is shut down by the controller to achieve overcurrent protection for the power device.

[0068] This embodiment also provides a power device protection method. Figure 7 is a flow chart of another power device protection method of this embodiment. Figure 7 As shown, the process includes the following steps:

[0069] Step S701, detecting the bus voltage through the comparator on the overvoltage control circuit, and detecting the power device current through the current control circuit; and executing step S702 and step S705 simultaneously;

[0070] Step S702, determining whether the bus voltage is overvoltage or undervoltage, if so, executing step S703, otherwise executing step S704;

[0071] Step S703, inputting a high level signal to the controller through the diode D1, so that the controller turns off the power device;

[0072] Step S704, inputting a low level signal to the controller through the diode D1, so that the controller controls the power device to operate normally;

[0073] Step S705, determining whether the current is greater than a preset current threshold, if so, executing step S706, otherwise, executing step S707;

[0074] Step S706, shutting down the power device through the controller;

[0075] Step S707, controlling the power device to operate normally through the controller.

[0076] Through the above steps S701 to S707, compared with the method of detecting signals through software in the prior art, this embodiment realizes the protection of bus voltage overvoltage and undervoltage by setting an overvoltage control circuit, and can realize the protection of power device overcurrent by setting an overcurrent control circuit. At the same time, a hardware comparator is used in the overvoltage control circuit to replace the current software signal acquisition method, which improves the speed of signal acquisition and transmission and improves the timeliness of power device protection. In addition, before the overvoltage control circuit collects a high-level signal and inputs it to the controller, a diode is set to prevent the influence of overvoltage and undervoltage on the current control circuit, which also increases the protection of power devices in the case of overvoltage.

[0077] In this embodiment, a refrigeration device is further provided, wherein the power device protection circuit described in any one of the above embodiments is provided, and the power device in the refrigeration device is protected by the power device protection circuit.

[0078] In this embodiment, a variable frequency refrigerator is also provided, wherein the power device protection circuit described in any of the above embodiments is provided, and the power device in the variable frequency refrigerator is protected by the power device protection circuit.

[0079] In addition, in combination with the power device protection method provided in the above embodiments, a storage medium may be provided in this embodiment to implement the power device protection method. The storage medium stores a computer program; when the computer program is executed by a processor, any power device protection method in the above embodiments is implemented.

[0080] It should be understood that the specific embodiments described herein are only used to explain the application, rather than to limit it. Based on the embodiments provided in this application, all other embodiments obtained by ordinary technicians in this field without creative work are within the protection scope of this application.

[0081] It should be noted that the user information (including but not limited to user device information, user personal information, etc.) and data (including but not limited to data used for analysis, stored data, displayed data, etc.) involved in this application are all information and data authorized by the user or fully authorized by all parties.

[0082] Obviously, the drawings are only some examples or embodiments of the present application. For ordinary technicians in the field, the present application can also be applied to other similar situations based on these drawings without creative work. In addition, it is understandable that although the work done in this development process may be complicated and lengthy, for ordinary technicians in the field, certain changes in design, manufacturing or production based on the technical content disclosed in this application are only conventional technical means and should not be regarded as insufficient content disclosed in this application.

[0083] The term "embodiment" in this application refers to a specific feature, structure or characteristic described in conjunction with the embodiment that can be included in at least one embodiment of the present application. The appearance of this phrase in various locations in the specification does not necessarily mean the same embodiment, nor does it mean that it is mutually exclusive with other embodiments and is independent or optional. It is clearly or implicitly understood by those of ordinary skill in the art that the embodiments described in this application can be combined with other embodiments without conflict.

[0084] Those skilled in the art can understand that all or part of the processes in the above-mentioned embodiment methods can be completed by instructing the relevant hardware through a computer program, and the computer program can be stored in a non-volatile computer-readable storage medium. When the computer program is executed, it can include the processes of the embodiments of the above-mentioned methods. Among them, any reference to the memory, database or other medium used in the embodiments provided in the present application can include at least one of non-volatile and volatile memory. Non-volatile memory can include read-only memory (ROM), magnetic tape, floppy disk, flash memory, optical memory, high-density embedded non-volatile memory, resistive random access memory (ReRAM), magnetoresistive random access memory (MRAM), ferroelectric random access memory (FRAM), phase change memory (PCM), graphene memory, etc. Volatile memory can include random access memory (RAM) or external cache memory, etc. As an illustration and not limitation, RAM can be in various forms, such as static random access memory (SRAM) or dynamic random access memory (DRAM). The database involved in each embodiment provided in this application may include at least one of a relational database and a non-relational database. Non-relational databases may include distributed databases based on blockchains, etc., but are not limited to this. The processor involved in each embodiment provided in this application may be a general-purpose processor, a central processing unit, a graphics processor, a digital signal processor, a programmable logic device, a data processing logic device based on quantum computing, etc., but are not limited to this.

[0085] The above-mentioned embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of patent protection. It should be pointed out that, for a person of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present application, and these all belong to the scope of protection of the present application. Therefore, the scope of protection of the present application shall be subject to the attached claims.

Claims

1. A power device protection circuit, characterized in that: include: Resistor R1, resistor R2, resistor R3, a first comparator, a second comparator, a signal output interface, a diode D1 and a controller; Among them, one end of the resistor R1 is connected to a power supply, the other end of the resistor R1 is connected in series with one end of the resistor R2 and the resistor R3 in sequence, the other end of the resistor R3 is then grounded, the first input end of the first comparator is connected to the midpoint of the resistor R1 and the resistor R2, the second input end of the first comparator is connected to the bus, the output end of the first comparator is connected to the signal output interface, the first input end of the second comparator is connected to the midpoint of the resistor R2 and the resistor R3, the second input end of the second comparator is connected to the bus, the output end of the second comparator is connected to the signal output interface, and the signal output interface is connected to the controller through the diode D1; the controller is used to control the shutdown of the power device according to the signal output by the signal output interface.

2. The power device protection circuit according to claim 1, characterized in that: The power device protection circuit further includes a resistor R4 and a capacitor C1; the diode D1, the resistor R4, the capacitor C1, the input pin of the controller and the signal output interface form an overvoltage control circuit; Among them, the signal output interface is connected to the positive electrode of the diode D1, the negative electrode of the diode D1 is connected to one end of the resistor R4, the other end of the resistor R4 is connected to one end of the capacitor C1, the other end of the resistor R4 is also connected to the input pin of the controller, and the other end of the capacitor C1 is grounded.

3. The power device protection circuit according to claim 1 or claim 2, characterized in that: The power device protection circuit further includes a resistor R5, a diode D2, a resistor R6, an output pin of a controller and a resistor R7; the resistor R5, the diode D2, the resistor R6, the resistor R4, an input pin of the controller and the resistor R7 form an overcurrent control circuit; Among them, one end of the resistor R5 is connected to the positive electrode of the diode D2, the negative electrode of the diode D2 is connected to one end of the resistor R6, the other end of the resistor R6 is grounded, the negative electrode of the diode D2 is also connected to one end of the resistor R4, the other end of the resistor R4 is connected to the input pin of the controller, one end of the resistor R7 is connected to the output pin of the controller, the other end of the resistor R7 is grounded, and the other end of the resistor R7 is also connected to the other end of the resistor R5.

4. The power device protection circuit according to claim 1, characterized in that: The first comparator and the second comparator are nanoscale voltage comparators.

5. The power device protection circuit according to claim 1, characterized in that: The controller is a power device driver chip.

6. A power device protection method, using the power device protection circuit described in any one of claims 1 to 5, characterized in that: include: Obtaining a voltage protection range of the bus voltage according to the resistor R1, the resistor R2, the resistor R3, the first comparator, and the second comparator; When it is detected that the bus voltage exceeds the voltage protection range, a high level signal is output through the signal output interface; The high level signal is input to the controller through the diode D1, so that the controller turns off the power device.

7. The power device protection method according to claim 6, characterized in that: The method further comprises: The power device protection circuit includes an overcurrent control circuit, which detects the current of the power device and determines whether the current is greater than a preset current threshold. If so, the power device is turned off by the controller.

8. A refrigeration device, characterized in that: The invention comprises a power device protection circuit as claimed in any one of claims 1 to 5.

9. A variable frequency refrigerator, characterized in that: The invention comprises a power device protection circuit as claimed in any one of claims 1 to 5.

10. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the steps of the power device protection method according to any one of claims 6 to 7 are implemented.

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