IGBT temperature automatic control system

Abstract

The utility model belongs to the technical field of inverter power supplies, and particularly relates to an IGBT (Insulated Gate Bipolar Translator) temperature automatic control system which comprises an IGBT temperature detection circuit, a singlechip, an RS485 communication circuit, a refrigerator, a water path, a radiator and a connection relation thereof. According to the utility model, the IGBT temperature detection circuit is arranged, so that the temperature of the IGBT can be monitored in real time, the operating temperature of the refrigerator can be adjusted in real time, when the temperature of the IGBT is too high, the temperature of cooling water is reduced, and when the temperature of the IGBT is too low, the refrigerating capacity is reduced, so that the temperature of the cooling water is not too low.

Description

Technical Field

[0001] The utility model relates to the technical field of inverter power supplies, and particularly relates to an IGBT temperature automatic control system. Background Art

[0002] IGBT is the core device of an inverter power supply, and the operating temperature of IGBT is the key factor determining the reliability of IGBT. The IGBT operating temperature is closely related to the temperature of the cooling water. If the cooling water temperature is too high, the IGBT temperature will be too high, which will cause the IGBT to thermally break down and cause permanent damage; if the cooling water temperature is too low, the IGBT temperature will be too low, and condensation will occur, resulting in a decrease in the insulation of the IGBT and triggering a voltage breakdown fault.

[0003] In high-power inverter power supplies, IGBT is usually used as the inverter device. When IGBT operates in a switching mode, it will generate certain losses, generally including on-state losses and switching losses. The on-state losses are related to power. The greater the power and the larger the current, the greater the losses of IGBT; the switching losses refer to the losses generated during the turn-on and turn-off processes of IGBT, which are related to the inverter frequency. The higher the inverter frequency, the greater the losses, and the lower the inverter frequency, the smaller the losses. These losses will ultimately generate heat, causing the temperature of IGBT to rise. To prevent the IGBT temperature from being too high, water cooling is generally used to dissipate heat from the IGBT. The temperature of the cooling water is directly related to the heat dissipation effect of the IGBT. If the cooling water temperature is too high, the radiator temperature will be too high, resulting in too high an IGBT temperature. Once the operating temperature allowed by the IGBT is exceeded, the IGBT will thermally break down and cause permanent damage.

[0004] Usually, a refrigerating machine is used to cool the cooling water to ensure that the cooling water temperature is not too high. During the heating-up process, the required power is relatively large, the losses of IGBT are also relatively large, the temperature rise is relatively high, and the required cooling water temperature needs to be relatively low, otherwise the heat dissipation effect is not ideal. During the heat preservation process, the required power is relatively small, the IGBT losses are also relatively small, the temperature rise is relatively low, and the cooling water temperature does not need to be too low, otherwise condensation may occur. Especially in the vacuum furnace system, when the heating is completed and the inverter power supply stops working, the temperature in the furnace is still very high, and the induction coil, furnace wall, etc. still need to be cooled continuously. The cooling water cannot stop immediately. At this time, the IGBT has stopped working and no longer generates heat, which will cause the temperature of the IGBT and the radiator to be too low, and it is very easy to cause condensation and insulation breakdown faults.

[0005] It should be noted that the information disclosed in the above background art section is only used to enhance the understanding of the background of the present utility model, and thus may include information that does not constitute the prior art known to those of ordinary skill in the art. Summary of the Utility Model

[0006] The object of the present utility model is to solve the technical problems existing in the background art. For this purpose, an IGBT temperature automatic control system is provided, which mainly monitors the IGBT temperature in real time through an improved IGBT temperature detection circuit, thereby adjusting the operating temperature of the refrigerator in real time to meet the requirements for the cooling water temperature when the heat generation of the IGBT is different, ensuring both the heat dissipation effect of the IGBT and preventing condensation.

[0007] In order to achieve the above object, the technical solution adopted by the present utility model is as follows:

[0008] The IGBT temperature automatic control system includes an IGBT temperature detection circuit, a single-chip microcomputer, an RS485 communication circuit, a refrigerator, a water circuit, and a radiator;

[0009] The IGBT temperature detection circuit is electrically connected to the single-chip microcomputer, the single-chip microcomputer is electrically connected to the RS485 communication circuit, and the RS485 communication circuit is communicatively connected to the refrigerator; the water outlet of the refrigerator is connected to the water inlet of the radiator through the water circuit, the water inlet of the refrigerator is connected to the water outlet of the radiator through the water circuit, and the IGBT is installed on the radiator;

[0010] The IGBT temperature detection circuit includes a voltage regulator IC1 and an operational amplifier IC2;

[0011] The anode of the voltage regulator IC1 is grounded, the reference electrode and the cathode of the voltage regulator IC1 are connected and connected to the supply voltage VCC through a resistor R1, the cathode of the voltage regulator IC1 is connected to a resistor R2, and the resistor R2 is connected to a thermistor R inside the IGBT NTC , the thermistor R NTC is connected to a resistor R3;

[0012] A resistor R4 is connected between the thermistor R NTC and the resistor R3, and the resistor R4 is connected to the non-inverting input terminal of the operational amplifier IC2 and a capacitor C1;

[0013] The output terminal of the operational amplifier IC2 is connected to the single-chip microcomputer through a resistor R7.

[0014] The following is a further limited technical solution of the present utility model. The resistors R2, the thermistor R NTC , and the resistor R3 are connected in series, and the other end of the resistor R3 is grounded; the capacitor C1 is grounded.

[0015] The following is a further limited technical solution of the present utility model. The inverting input terminal of the operational amplifier IC2 is connected to a resistor R5, and the resistor R5 is grounded;

[0016] A resistor R6 is connected between the inverting input terminal and the output terminal of the operational amplifier IC2.

[0017] The following is a further limited technical solution of the present utility model. A capacitor C2 is connected between the resistor R7 and the single-chip microcomputer, and the capacitor C2 is grounded.

[0018] Compared with the prior art, the present utility model has the following technical effects:

[0019] By setting the IGBT temperature detection circuit, the present utility model can monitor the IGBT temperature in real time, so as to adjust the operating temperature of the refrigerator in real time. When the IGBT temperature is too high, the cooling water temperature is reduced. When the IGBT temperature is too low, the refrigerating capacity is reduced, so that the cooling water temperature will not be too low.

[0020] The following further describes the present utility model in conjunction with the drawings and embodiments. Description of the Drawings

[0021] In order to more clearly illustrate the technical solutions in the embodiments of the present utility model or the prior art, the following will briefly introduce the drawings required to be used in the embodiments or the prior art. Obviously, the drawings in the following description are only some embodiments of the present utility model. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0022] Figure 1 It is the circuit connection relationship diagram of the IGBT temperature detection circuit in the present utility model;

[0023] Figure 2 It is the circuit connection relationship diagram of the RS485 communication circuit in the present utility model;

[0024] Figure 3 It is the change curve diagram of the internal thermistor of the IGBT in the present utility model, where the abscissa is the temperature and the ordinate is the resistance value;

[0025] Figure 4 It is the system connection relationship diagram of the present utility model. Detailed Embodiments

[0026] In order to make the above-mentioned objects, features and advantages of the present utility model more obvious and understandable, the following detailed description of the specific embodiments of the present utility model is made in conjunction with the drawings. Many specific details are set forth in the following description in order to fully understand the present utility model. However, the present utility model can be implemented in many other ways different from those described herein. Those skilled in the art can make similar improvements without departing from the connotation of the present utility model. Therefore, the present utility model is not limited by the specific embodiments disclosed below.

[0027] Such as Figure 4As shown in the figure, an IGBT temperature automatic control system is provided, which consists of an IGBT temperature detection circuit, a single-chip microcomputer, an RS485 communication circuit, a refrigerator, a water circuit, a radiator, etc. It should be noted that the electrical connection relationship between the single-chip microcomputer and the RS485 communication circuit is an existing technology, and this embodiment will not describe it in detail; the communication connection relationship between the RS485 communication circuit and the refrigerator is an existing technology, and this embodiment will not describe it in detail; the mechanical connection relationship among the refrigerator, the water circuit and the radiator is an existing technology, and this embodiment will not describe it in detail.

[0028] The main improvement of this system lies in the IGBT temperature detection circuit. Through the improved IGBT temperature detection circuit, the IGBT temperature is detected in real time, and then based on the receiving and transmitting technology of the single-chip microcomputer in the existing technology, the operation of the refrigerator is controlled, so as to control the IGBT temperature. It should be noted that the program codes and algorithm flows involved in the control process and data transmission process of this system are not within the protection scope of this utility model, and those skilled in the art can obtain the program codes or algorithm flows involved in the control process and data transmission process through conventional means. Specifically:

[0029] 1. IGBT temperature detection circuit

[0030] There is a thermistor R inside the IGBT NTC , and the variation curve of the thermistor R NTC is as shown in Figure 3 . This resistor is a negative temperature coefficient. When the IGBT temperature is higher, the resistance value is smaller, and when the temperature is lower, the resistance value is larger. By using the method of resistor voltage division, the IGBT temperature can be reflected through the voltage, as shown in Figure 1 .

[0031] As shown in Figure 1 , the voltage regulator IC1 is TL431, which can generate a reference voltage V ref of 2.5V. The resistors R2, R NTC , and R3 form a voltage division circuit. The relationship between the voltage V A at point A and each resistor and V ref is as follows:

[0032]

[0033] V A The voltage is proportional to the IGBT temperature.

[0034] V A After being filtered by R4 and C1 and then amplified by IC2, it becomes a voltage signal of about 1 - 2V and is sent to the single-chip microcomputer for A / D conversion to obtain the current working temperature of the IGBT.

[0035] 2. To resist interference and improve the reliability of RS485 communication, the RS485 communication circuit is isolated. As Figure 2 shown, the dedicated RS485 communication chip ADM2483 is used. This chip is an isolated differential bus transceiver, which has the advantages of low power consumption, strong anti-interference ability, and wide operating voltage range.

[0036] 3. The single-chip microcomputer conducts Modbus RTU communication with the refrigerator through the RS485 communication circuit, and changes the temperature setting value of the refrigerator according to a certain ratio based on the current working temperature of the IGBT. When the output power is large and the IGBT temperature is high, the temperature setting value of the refrigerator is reduced; when the output power is small or the machine is stopped, the temperature setting value of the refrigerator is increased to reduce the refrigeration capacity and ensure that condensation does not occur.

[0037] The above are only the preferred embodiments of the present invention, and do not impose any form of limitation on the present invention. Any person skilled in the art can make many possible changes and modifications to the technical solution of the present invention by using the methods and technical contents disclosed above, or modify it into equivalent embodiments with equivalent changes. Therefore, all equivalent changes made according to the shape, structure and principle of the present invention without departing from the content of the technical solution of the present invention shall be covered by the protection scope of the present invention.

Claims

1. An IGBT temperature automatic control system, characterized in that, It includes an IGBT temperature detection circuit, and the IGBT temperature detection circuit includes a voltage regulator IC1 and an operational amplifier IC2; The anode of the voltage regulator IC1 is grounded. The reference electrode and the cathode of the voltage regulator IC1 are connected and connected to the supply voltage VCC through a resistor R1. The cathode of the voltage regulator IC1 is connected to a resistor R2, and the resistor R2 is connected to a thermistor R inside the IGBT NTC , the thermistor R NTC is connected to a resistor R3; The thermistor R NTC A resistor R4 is connected between the thermistor R and the resistor R3. The resistor R4 is connected to the non-inverting input terminal of the operational amplifier IC2 and a capacitor C1; The output terminal of the operational amplifier IC2 is connected to the single-chip microcomputer through a resistor R7; The single-chip microcomputer conducts Modbus RTU communication with the refrigerator through the RS485 communication circuit, and changes the temperature set value of the refrigerator in proportion according to the current working temperature of the IGBT.

2. The IGBT temperature automatic control system according to claim 1, wherein It also includes an RS485 communication circuit, a refrigerator, a water circuit, and a radiator; The IGBT temperature detection circuit is electrically connected to the single-chip microcomputer, the single-chip microcomputer is electrically connected to the RS485 communication circuit, and the RS485 communication circuit is communicatively connected to the refrigerator; The water outlet of the refrigerator is connected to the water inlet of the radiator through a water circuit, the water inlet of the refrigerator is connected to the water outlet of the radiator through a water circuit, and the IGBT is installed on the radiator.

3. The IGBT temperature automatic control system according to claim 1, characterized in that, The resistor R2, the thermistor R NTC , and the resistor R3 are connected in series, and the other end of the resistor R3 is grounded; the capacitor C1 is grounded.

4. The IGBT temperature automatic control system according to claim 1, characterized in that, A resistor R5 is connected to the inverting input terminal of the operational amplifier IC2, and the resistor R5 is grounded; A resistor R6 is connected between the inverting input terminal and the output terminal of the operational amplifier IC2.

5. The IGBT temperature automatic control system according to claim 1, characterized in that A capacitor C2 is connected between the resistor R7 and the single-chip microcomputer, and the capacitor C2 is grounded.

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