Protection circuit for adding resettable fuse to IGBT circuit of frequency conversion controller for household electrical appliance

Abstract

The utility model discloses a protection circuit with a self-recovery fuse added to an IGBT circuit of a frequency conversion controller for household appliances. The protection circuit comprises a microprocessor MCU, a rectifier bridge BG1, a boost circuit, a self-recovery protection loop and a differential comparison amplification circuit. Two alternating current access ends of the rectifier bridge BG1 are used for connecting an external 220V alternating current power supply; the booster circuit comprises an inductor L1, a capacitor C1, a resistor R1, a diode D1 and an IGBT tube IG1; the self-recovery protection loop comprises a fuse FUSE1; the differential comparison amplification circuit comprises an operational amplifier IC1, resistors R2 to R9 (which means that the eight resistors are all included, so described), and capacitors C2 to C4; one end of the resistor R6 is connected with the operational amplifier IC1, and the other end of the resistor R6 is connected with the microprocessor MCU. According to the frequency conversion controller IGBT circuit for the household electrical appliance, the protection circuit of the resettable fuse is added, and the IGBT circuit has the advantages of being capable of automatically disconnecting the circuit when the IGBT pin of the driving board is short-circuited, simple in structure, low in cost, high in safety and the like.

Description

Technical Field

[0001] This utility model relates to a protection circuit, and more particularly to a protection circuit for an IGBT circuit of a frequency converter controller for household appliances with an added self-resetting fuse. Background Technology

[0002] The application of frequency conversion technology in home appliances is becoming increasingly widespread. However, problems such as arcing and fires have arisen in the frequency conversion drive boards used in refrigerators, air conditioners, and washing machines.

[0003] When the equipment is not in operation, foreign objects such as insects can enter the electrical appliance, causing short circuits in the IGBT (Insulated-Gate Bipolar Transistor) pins. When the circuit malfunctions or malfunctions, the current will continuously increase, potentially damaging some important electronic components in the circuit, burning out the circuit, or even causing a fire.

[0004] like Figure 3 The existing control circuits do not have protection circuits. In many air conditioners on the market, insects such as flying insects and geckos enter the air conditioner, causing IGBT arcing and overcurrent damage, which in turn leads to rectifier bridge breakdown, and in severe cases, air conditioner fire, causing accidents that endanger the personal safety and property of customers.

[0005] Therefore, there is an urgent need to design a protection circuit that can solve the problem of short circuits in IGBT pins. Utility Model Content

[0006] This invention aims to overcome the shortcomings of the existing technology by providing a protection circuit for the IGBT circuit of a frequency converter controller for home appliances, which adds a self-resetting fuse to solve the problem that short circuits in the IGBT pins of the driver board can easily cause fires.

[0007] The present invention adopts the following technical solution to solve the technical problem.

[0008] This utility model provides a protection circuit for an IGBT circuit of a frequency converter controller for home appliances with an added self-resetting fuse, including a microprocessor MCU, a rectifier bridge BG1, a boost circuit, a self-resetting protection circuit, and a differential comparator amplifier circuit.

[0009] The two AC input terminals of the rectifier bridge BG1 are used to connect to an external 220V AC power supply, and a capacitor C5 is connected between the two output terminals of the rectifier bridge BG1.

[0010] The boost circuit includes an inductor L1, a capacitor C1, a resistor R1, a diode D1, and an IGBT transistor IG1.

[0011] The self-resetting protection circuit includes fuse FUSE1;

[0012] The differential comparison amplification circuit comprises an operational amplifier IC1, resistors R2-R9 and capacitors C2-C4; one end of the resistor R6 is connected to the operational amplifier IC1, and the other end of the resistor R6 is connected to the microprocessor MCU.

[0013] The structure of the protection circuit with the self-recovery fuse added to the frequency converter controller IGBT circuit for household appliances also has the following characteristics:

[0014] Further, the microprocessor MCU is R5F524T.

[0015] Further, the operational amplifier IC1 is LM331.

[0016] Further, the diode D1 is MUR40FU60DCT.

[0017] Compared with the prior art, the utility model has the beneficial effects that:

[0018] The utility model discloses a kind of protection circuit with the self-recovery fuse added to frequency converter controller IGBT circuit for household appliances, including microprocessor MCU, rectifier bridge BG1, boost circuit, self-recovery protection loop and differential comparison amplification circuit;Two AC access ends of rectifier bridge BG1 are used to connect external 220V AC power supply;Boost circuit includes inductor L1, capacitor C1, resistor R1, diode D1 and IGBT tube IG1;Self-recovery protection loop includes fuse FUSE1, resistor R2-resistor R3, resistor R7-resistor R8 and diode D1;Differential comparison amplification circuit includes operational amplifier IC1, resistor R4-resistor R6, resistor R9, capacitor C2-capacitor C4;One end of the resistor R4 is connected to the operational amplifier IC1, and the other end of the resistor R4 is connected to the microprocessor MCU.

[0019] The utility model discloses a kind of protection circuit with the self-recovery fuse added to frequency converter controller IGBT circuit for household appliances, with the advantages of automatically disconnecting circuit when being able to drive board IGBT pin short circuit, simple structure, low cost, high safety and the like. DRAWINGS

[0020] Figure 1 It is the structure block diagram of the utility model's a kind of protection circuit with the self-recovery fuse added to frequency converter controller IGBT circuit for household appliances.

[0021] Figure 2 It is the circuit diagram of the utility model's a kind of protection circuit with the self-recovery fuse added to frequency converter controller IGBT circuit for household appliances.

[0022] Figure 3 It is the structure block diagram of prior art's frequency converter controller IGBT circuit for household appliances.

[0023] The utility model is further described below by specific implementation and in connection with the drawings. Specific Implementation

[0024] Reference Figures 1-2 The utility model discloses a kind of frequency converter controller IGBT circuits of home appliance increasing self-restoration fuse protection circuit, including microprocessor MCU, rectifier bridge BG1, boost circuit, self-restoration protection circuit and differential comparison amplification circuit;

[0025] Two AC access ends of the rectifier bridge BG1 are used to connect external 220V AC power supply, and the capacitor C5 is connected between the two output ends of the rectifier bridge BG1.

[0026] The boost circuit includes inductor L1, capacitor C1, resistor R1, diode D1 and IGBT tube IG1.

[0027] The working principle of the boost circuit is that when IG1 is turned on, the voltage is stored by inductor L1. When IG1 is disconnected, inductor L1 discharges the subsequent circuit, and at this time the output voltage of rectifier bridge BG1 is superimposed, the voltages are added, and the overall output voltage is improved. The on-time of IG1 is adjusted by MCU sending PWM waveform, and the longer the on-time is, the higher the voltage is. Diode D1 acts as reverse blocking to prevent reverse flow of voltage. The structure of diode D1 includes two diodes in parallel connection to improve the overcurrent capacity of diode D1.

[0028] The self-restoration protection circuit includes fuse FUSE1.

[0029] The differential comparison amplification circuit includes operational amplifier IC1, resistors R2-R9 and capacitors C2-C4. One end of resistor R6 is connected to operational amplifier IC1, and the other end of resistor R6 is connected to microprocessor MCU.

[0030] As Figure 1 The utility model discloses a kind of frequency converter controller IGBT circuits of home appliance increasing self-restoration fuse protection circuit, it is applicable to refrigerator, air conditioner, washing machine with frequency converter controller. By increasing self-restoration protection circuit and differential amplification circuit protection IGBT will not overcurrent damage, and will not cause circuit overcurrent fire burn machine etc. when failure occurs. Can solve the IGBT spark overcurrent damage caused by flying insects, geckos, etc. insects in air conditioner, in turn lead to rectifier bridge breakdown, serious air conditioner fire, cause fire, cause customer personal property safety problem. In the utility model, a self-restoration protection circuit with fuse is added at IGBT. Increase this circuit device structure in circuit, relatively low cost.

[0031] In specific implementation, the microprocessor MCU is R5F524T.

[0032] The R5F524T microcontroller has a built-in FPU, which makes it easy to program complex inverter control algorithms suitable for applications that require high-precision floating-point operations. The R5F524T performs well in terms of processing speed and efficiency, meeting the high requirements of real-time control and data processing.

[0033] In specific implementation, the operational amplifier IC1 is LM331.

[0034] LM331 is an integrated chip produced by NS Company in the United States, which has high performance and price ratio. It can be used as a precision frequency voltage converter, A / D converter, linear frequency modulation demodulation, long-time integrator and other related devices. LM331 uses a new temperature compensation energy gap reference circuit, which has high precision in the entire working temperature range and low to 4.0V power supply voltage. LM331 has a wide dynamic range, up to 100dB; good linearity, maximum nonlinear distortion less than 0.01%, good linearity when working frequency is as low as 0.1Hz; high conversion accuracy, digital resolution up to 12 bits; simple external circuit, only a few external components can be easily connected to form V / F or F / V conversion circuit, and the conversion accuracy can be easily guaranteed.

[0035] In specific implementation, the diode D1 is MUR40FU60DCT.

[0036] MUR40FU60DCT is a fast recovery diode packaged in TO247, with parameters of 40A / 600V, and has ultra-fast recovery time, which performs well in high-frequency applications, and is commonly used in inverters, electric welders and other equipment. MUR40 diode has high voltage resistance, can withstand high voltage, suitable for circuits that require high voltage resistance, can withstand large forward current, suitable for circuits that require large current processing. MUR40 diode, small size, easy to install, and due to its fast recovery characteristics and small junction capacitance, MUR40 diode can reduce energy loss during operation and improve the overall system efficiency.

[0037] The circuit diagram of the protection circuit of the utility model is shown in Figure 2 The connection relationship between each component is shown in Figure 2In the specific work, the voltage of one end of the fuse FUSE1 is divided by the sampling resistors R2, R3 and R5, and then enters the first pin of the operational amplifier IC1. The voltage of the other end of the fuse FUSE1 is divided by the sampling resistors R7, R8 and R9, and then enters the third pin of the operational amplifier IC1. The IC1 compares the voltage of the first pin and the third pin, and outputs the result to the fourth pin (the voltage value is 5V or 0V). Then, the voltage is sent to the OV_P terminal of the MCU.

[0038] The gate of the IGBT tube IG1 is connected to the PWM wave input end PWM_IN through the diode D2 and the resistor R10 in sequence, and the gate of the IGBT tube IG1 is also connected to the PWM wave input end PWM_IN through the resistor R12. One end of the resistors RS1-RS4 connected in parallel is connected to the rectifier bridge BG1, and the other end of the resistors RS1-RS4 connected in parallel is connected to the collector of the IGBT tube IG1. The collector of the IGBT tube IG1 is also connected to the emitter of the IGBT tube IG1 through the resistor R11 and the capacitor C6 in sequence.

[0039] The emitter of the IGBT tube IG1 is connected to one end of the fuse FUSE1.

[0040] When there is no abnormal large current through the IGBT, the fuse FUSE1 is turned on, the voltages of the first pin and the third pin of the operational amplifier IC1 are equal, at this time, the operational amplifier IC1 outputs a high level to the MCU, and when the MCU detects the high level, no error warning is reported, and the household appliance frequency conversion controller works normally.

[0041] When there is an abnormal large current through the IGBT, the fuse FUSE1 is disconnected, the voltages of the first pin and the third pin of the operational amplifier IC1 are not equal, the negative input voltage of the first pin is high, and the positive input voltage of the third pin is zero. At this time, the operational amplifier IC1 outputs a low level to the MCU, and when the MCU detects the low level, an error warning is reported. The household appliance frequency conversion controller cannot work. The MCU detects the abnormality and sends an error prompt, and the maintenance personnel can judge that there is an abnormality in the IGBT and process it through the prompt.

[0042] The household appliance frequency conversion controller IGBT circuit of the utility model adds the protection circuit of the self-restoring fuse, when there is no abnormal large current through the IGBT, the voltages collected by the two input ends of the differential comparison amplification circuit operational amplifier IC1 are normal, the operational amplifier IC1 outputs a high level, which is input to the OV_P terminal of the MCU through the resistor R6, and the MCU detects the normal work.

[0043] When there is an abnormal large current through the IGBT, the fuse of the self-recovery protection circuit will be self-fused to cut off the current when the current abnormally rises to a certain height and heat, thereby playing a role in protecting the safe operation of the circuit. When the fuse is disconnected, the voltage collected by the two input terminals of the operational amplifier IC1 is abnormal, the operational amplifier IC1 outputs a low level, and the low level is input to the OV_P terminal of the MCU through the resistance R6, so that the MCU detects the abnormality and issues an error prompt, and the maintenance personnel can determine that there is an abnormality in the IGBT and process it according to the prompt.

[0044] When there is no abnormal large current through the IGBT, the voltage collected by the two input terminals of the operational amplifier IC1 is normal, the operational amplifier IC1 outputs a high level, and the MCU detects normal operation.

[0045] The utility model discloses a kind of frequency converter controller IGBT circuits for household appliance increase self-recovery fuse protection circuit, increase self-recovery protection circuit with fuse in IGBT working loop, differential comparison amplification circuit detects IGBT loop current size in real time, when IGBT short circuit caused by insects and other foreign matters in circuit, self-recovery fuse disconnects IGBT in protection circuit instantaneously, and IGBT loop current size is detected in real time by differential comparison amplification circuit. When IGBT short circuit caused by insects and other foreign matters in circuit, fuse disconnects IGBT in protection circuit instantaneously, prevent IGBT from being damaged by overcurrent.

[0046] After maintenance personnel troubleshoots problem and cleans up fault, self-recovery fuse restores normal and is reused repeatedly, and equipment is continued to be operated after power-on.

[0047] For those skilled in the art, it is obvious that the utility model is not limited to the details of the above exemplary embodiments, and can be realized in other specific forms without departing from the spirit or basic characteristics of the utility model. Therefore, from any point of view, the embodiments should be regarded as exemplary and non-limiting, and the scope of the utility model is defined by the appended claims rather than the above description, so as to include all changes within the meaning and scope of the equivalent elements of the claims in the utility model. Any reference signs in the claims should not be regarded as limiting the claims involved.

[0048] In addition, it should be understood that, although the present specification is described in terms of embodiments, not every embodiment contains only one independent technical solution, and the description manner of the specification is only for the sake of clarity, and those skilled in the art should regard the specification as a whole, and the technical solutions in each embodiment can also be properly combined to form other embodiments that those skilled in the art can understand.

Claims

1. A protection circuit for an IGBT circuit in a household appliance frequency converter, characterized by adding a self-resetting fuse, wherein... The microprocessor MCU, the rectifier bridge BG1, the voltage boosting circuit, the self-recovery protection circuit and the differential comparison amplification circuit are included. Two AC input ends of the rectifier bridge BG1 are used for connecting an external 220V AC power supply, and a capacitor C5 is connected between two output ends of the rectifier bridge BG1. The voltage boosting circuit includes an inductor L1, a capacitor C1, a resistor R1, a diode D1 and an IGBT tube IG1. The self-recovery protection circuit includes a fuse FUSE1. The differential comparison amplification circuit includes an operational amplifier IC1, resistors R2-R9 and capacitors C2-C4; one end of the resistor R6 is connected to the operational amplifier IC1, and the other end of the resistor R6 is connected to the microprocessor MCU.

2. The protection circuit for an IGBT circuit of a frequency converter controller for home appliances with an added self-resetting fuse according to claim 1, characterized in that, The microprocessor MCU is R5F524T.

3. The protection circuit for an IGBT circuit of a frequency converter controller for home appliances with an added self-resetting fuse according to claim 1, characterized in that, The operational amplifier IC1 is LM331.

4. The protection circuit for an IGBT circuit of a frequency converter controller for home appliances with an added self-resetting fuse according to claim 1, characterized in that, The diode D1 is MUR40FU60DCT.

Images