CN218822802U

CN218822802U - Power module temperature inspection system

Info

Publication number: CN218822802U
Application number: CN202223208758.3U
Authority: CN
Inventors: 王青龙; 祁招; 石鹏; 左广杰; 王琼; 王志伟; 宋豪; 陈柯旭; 常子明
Original assignee: Henan Xuji Power Electronics Co ltd
Current assignee: Henan Xuji Power Electronics Co ltd
Priority date: 2022-11-30
Filing date: 2022-11-30
Publication date: 2023-04-07
Anticipated expiration: 2032-11-30

Abstract

The utility model belongs to the power electronics field, concretely relates to power module temperature system of patrolling and examining, a voltage acquisition module for setting up at power module inside, patrol and examine circuit module, pressure conversion module and control module frequently, can realize the real-time detection to the inside temperature of a plurality of power module IGBT in the system, circuit structure is simple, the precision is high, and is with low costs, gather multichannel temperature sensor's temperature in a flexible way, easily realize detecting and protecting a plurality of power module's temperature, and keep apart the former secondary limit of frequency signal through the opto-coupler isolation module, prevent to receive the interference that arouses because of electric connection.

Description

Power module temperature inspection system

Technical Field

The utility model belongs to the power electronics field, concretely relates to power module temperature system of patrolling and examining.

Background

With the development of semiconductor technology, IGBT (insulated gate bipolar transistor) power devices are widely used in the power electronics industry and play an irreplaceable role in national economy. For a high-power IGBT device, the device usually works under a high-voltage and high-current state, a semiconductor device is very sensitive to temperature, the temperature of the device can be increased along with the temperature when the heat dissipation power is lost, and if the temperature of the IGBT exceeds a set value, the device must be operated in a derating mode or stopped to operate so as to ensure the safety of the device.

At present, over-temperature protection is not designed on most of commercially available IGBT driving boards, and IGBT damage caused by over-temperature accounts for a large proportion. The main modes for detecting the temperature of the IGBT are as follows: the temperature of a certain point on the radiator close to the IGBT is measured by using the temperature switch, the temperature of the certain point has a certain functional relation with the temperature of the IGBT, but the product is high in price, large in error and complex in structure, and only whether the temperature of the IGBT exceeds a certain value can be detected, and real-time detection cannot be achieved. The prior art provides a real-time temperature detection circuit formed based on an NTC resistor inside an IGBT, but the scheme can only detect the temperature of the IGBT of one power module, and a plurality of detection circuits are needed for a system with a plurality of power modules, so that the complexity and the cost of the system are increased.

SUMMERY OF THE UTILITY MODEL

An object of the utility model is to provide a power module temperature system of patrolling and examining for solve the technical problem that power module temperature can not real-time detection.

In order to solve the technical problem, the utility model provides a power module temperature inspection system, which comprises a voltage acquisition module, an inspection circuit module, a voltage-frequency conversion module and a control module; the voltage acquisition module comprises a plurality of voltage sampling circuits, and each voltage sampling circuit is used for acquiring the temperatures of different power modules and outputting a voltage value corresponding to the temperature; the inspection circuit module comprises a plurality of inspection circuits which are in one-to-one correspondence with the voltage sampling circuits, each inspection circuit comprises an operational amplifier and a diode, the homodromous input end of the operational amplifier is connected with the output end of the corresponding voltage sampling circuit, the diode is connected with the output end of the operational amplifier in series, the cathode of the diode is connected with the output end of the operational amplifier, and the reverse input end of the operational amplifier is connected with the anode of the diode; the anodes of all the diodes are connected with the voltage-frequency conversion module so as to output the minimum voltage value in the voltage values output by each voltage acquisition module to the voltage-frequency conversion module, the voltage-frequency conversion module is used for performing voltage-frequency conversion, and the voltage-frequency conversion module is connected with the control module and is used for transmitting the converted frequency signals to the control module.

The beneficial effects are as follows: the utility model discloses a be used for setting up at the inside voltage acquisition module of power module, patrol and examine circuit module, voltage conversion module and control module frequently. The voltage acquisition module comprises a thermistor, a divider resistor and a filter capacitor which are connected in series, and is used for outputting a voltage division signal of the thermistor; the inspection circuit module comprises a hardware comparison circuit consisting of an operational amplifier and a diode and is used for outputting a minimum voltage sampling value in the three-phase voltage acquisition circuit; the voltage-frequency conversion module comprises a voltage-frequency converter and is used for receiving the signal output by the inspection circuit module and converting the voltage signal into a frequency signal; the control module is used for processing the frequency signal and realizing the temperature detection of the temperature sensor. The temperature inspection method has the advantages of simple circuit, high precision, low cost, flexibility and easy realization.

Furthermore, the voltage sampling circuit comprises a thermistor and a divider resistor which are arranged in series, and the voltage dividing point of the thermistor and the divider resistor is the output end of the voltage sampling circuit.

The beneficial effects are as follows: the thermistor and the voltage dividing resistor are used for outputting voltage dividing signals of the thermistor, so that the precision is improved.

Furthermore, the voltage sampling circuit also comprises a filter capacitor, and the filter capacitor is connected in parallel at two ends of the thermistor.

The beneficial effects are as follows: the filter capacitor is used for filtering out clutter and improving detection accuracy.

Further, the voltage-frequency conversion module comprises a voltage-frequency converter; the input end of the voltage-frequency converter is connected with the output end of the voltage acquisition module through the first RC filter circuit, and the frequency output end of the voltage-frequency converter is connected with the control module.

The beneficial effects are as follows: the voltage-frequency conversion module is used for receiving the signal output by the inspection circuit module and converting the voltage signal into a frequency signal, so that the control module can process the signal conveniently.

Furthermore, the power module temperature inspection system also comprises an optical coupling isolation module, and the voltage-frequency conversion module is connected with the control module through the optical coupling isolation module; the optical coupler isolation module comprises an optical coupler, one end of the primary side of the optical coupler is connected with a first power supply through a first pull-up resistor, and the other end of the primary side of the optical coupler is connected with the output end of the voltage-frequency conversion module; one end of the optical coupler secondary side is connected with a second power supply, the other end of the optical coupler secondary side is connected with the control module, and the optical coupler secondary side is further connected with the second power supply through a second pull-up resistor.

The beneficial effects are as follows: the optical coupling isolation module is used for isolating the received frequency signals, and detection accuracy is improved.

Furthermore, the power module temperature inspection system further comprises a filtering module, the filtering module is a second RC filtering circuit, and the other end of the optical coupler secondary side is connected with the control module through the second RC filtering circuit.

The beneficial effects are as follows: the filtering module is used for filtering out clutter and further improving the detection accuracy.

Further, the control module is an FPGA.

The beneficial effects are as follows: the control module is an FPGA, so that the overall performance of the system is improved.

Further, the thermistor is an NTC resistor, PT100 or thermocouple.

The beneficial effects are as follows: the temperature is detected by the thermistor, so that the detection precision is improved.

Drawings

Fig. 1 is the utility model discloses a circuit diagram is patrolled and examined to IGBT temperature.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more clear, the present invention is further described in detail with reference to the accompanying drawings and embodiments.

The power module temperature inspection system comprises:

the utility model discloses a power module (this embodiment adopts IGBT) temperature system of patrolling and examining, including the voltage acquisition module that is used for setting up inside the IGBT, namely voltage acquisition module (NTC bleeder circuit), patrol and examine circuit module, pressure frequency conversion module LM231, opto-coupler isolation module, filtering module and FPGA control module; wherein first voltage acquisition circuit of voltage acquisition module includes: a first path of voltage sampling circuit consisting of an NTC thermistor NTC-1, a divider resistor R1 and a filter capacitor C1 in the first power module IGBT, wherein one end of the thermistor NTC-1 is connected with the input end of the inspection circuit and is also connected with a first power supply VCC through the divider resistor R1; the other end of the thermistor R1 is grounded, and the two ends of the thermistor R1 are also connected with a filter capacitor C1 in parallel.

The second temperature sampling circuit composed of the NTC resistor NTC-2 inside the second power module IGBT, the divider resistor R2 and the filter capacitor C2, and the voltage sampling circuit composed of the NTC resistor NTC-n inside the nth power module IGBT, the divider resistor Rn and the filter capacitor Cn are respectively used as the input of the inspection circuit module (the connection mode of the second to nth voltage sampling circuits is the same as that of the first voltage sampling circuit).

The inspection circuit module comprises An inspection circuit consisting of operational amplifiers A1, A2, 8230A, an and diodes D1, D2, 8230A, 8230Dn, wherein the operational amplifiers A1 and the diodes D1 are taken as examples:

the homodromous input end of the operational amplifier A1 is connected with the output end of the voltage acquisition circuit, and the output end of the operational amplifier A1 is connected with the cathode of the corresponding diode D1; the reverse input end of the operational amplifier A1 is connected with the anode of the diode D1; the anode of the diode D1 is connected with the voltage-frequency conversion module (the connection mode of other operational amplifiers and diodes is the same as the above).

The inspection circuit module outputs the minimum voltage value in the multi-path sampling values as the voltage input of the voltage-frequency conversion module; wherein R4, R5, R6, R7, C4, C5, C6 and U1 form a voltage-frequency conversion circuit to realize the conversion between voltage and frequency; the voltage-to-frequency conversion circuit includes: a voltage-to-frequency converter U1 (LM 231); the input end of the voltage-frequency converter U1 is connected with the output end of the voltage acquisition module, and the output end of the voltage-frequency converter U1 is also provided with a first filter circuit consisting of a filter resistor R4 and a filter capacitor C4; the frequency output end is connected with the control module and used for realizing the conversion between voltage and frequency.

The optical coupler isolation module comprises an optical coupler U2, one end of the primary side of the optical coupler U2 is connected with a first power supply VCC through a first pull-up resistor R8, and the other end of the primary side of the optical coupler U2 is connected with the output end of the voltage-frequency conversion module; one end of the secondary side of the optocoupler U2 is connected with the control module and is also connected with a second power supply VCC _5V through a second pull-up resistor R9; the other end of the secondary side of the optocoupler U2 is connected with the control module, is also connected with a second power supply VCC _5V through a second pull-up resistor R9, and is also connected with the control module through a second RC filter circuit; the filtering module comprises a second filtering circuit consisting of a filtering resistor R10 and a filtering capacitor C7 and is arranged at one end of the secondary side of the optocoupler U2.

The FPGA computing circuit implements processing of the frequency signal, as shown in fig. 1.

The specific detection process is as follows: the power supply voltage VCC obtains a stable NTC resistance voltage division value UNTC-2 through the resistor R2 and the IGBT internal NTC resistance NTC-2, and the NTC resistance NTC-n inside the IGBT of the nth power module, the voltage division value Rn and the filter capacitor Cn form an nth voltage sampling circuit, and the power supply voltage VCC is connected with the NTC resistance NTC-n inside the IGBT of the nth power module, the voltage division value Rn and the filter capacitor Cn form the nth voltage sampling circuitThe over-resistance Rn and the NTC resistance NTC-n inside the IGBT obtain stable NTC resistance partial pressure values UNTC-n, UNTC-1, UNTC-2 and UNTC-n which are used as the input of the inspection circuit, the inspection circuit comprises operational amplifiers A1, A2, 8230, an and diodes D1, D2, 8230, 8230and Dn, and if U is the principle of 'virtual short' and 'virtual break', the operational amplifier operates according to the operating principle of the operational amplifier _NTC-1 Minimum, according to the 'virtual short' principle, the voltages Vp and Vn at the two ends of the A1 operational amplifier input are equal and are U _NTC-1 (ii) a Operational amplifiers A1, A2, \8230 `, the negative input terminals of An are all clamped to U by voltage _NTC-1 Because the A2, \ 8230 \ 8230An operational amplifier works in a non-linear region, the output end of the operational amplifier is Vcc-Vf, the output end is connected with the diode D2, \ 8230 \ 8230, the voltage of a Dn cathode is greater than the voltage of An anode, so that D1 is conducted, D2, \\ 8230 \ 8230and Dn is cut off, the voltage acquisition module outputs a first path of voltage sampling value, namely n paths of voltage sampling minimum values, corresponding to NTC resistors in a module with the highest temperature, the output of the inspection circuit module is used as the voltage input of the voltage-frequency conversion circuit, the UNTC voltage value passes through a resistor R4 to the input end U1 of the voltage-frequency conversion circuit, the voltage-frequency conversion circuit comprises R4, R5, R6, R7, C4, C5, C6 and U1 to realize the conversion between voltage and frequency, wherein the C5 and the R5 form a resonant network of the voltage-frequency conversion circuit, and the R7 resistor forms a parameter adjusting resistor of the voltage-frequency conversion circuit, R6 and C6 form a frequency adjusting parameter and are connected with a power supply VCC, F-OUT outputs frequency to An optical coupling isolation and filter circuit, the optical coupling isolation and filter circuit comprises R8, R9, R10, C7 and U2 and is used for realizing the isolation of a primary side signal and a secondary side signal and the isolation of a frequency signal, the output end F-OUT of a voltage-frequency conversion circuit is connected with the optical coupling isolation and filter circuit, R8 is connected with the power supply VCC to form An optical coupling primary side circuit, R9 is connected with VCC _5V to form An optical coupling secondary side circuit, R10 and C7 form a first-order low-pass filter circuit, the signal is filtered and then sent to An FPGA controller, the FPGA controller processes the signal, the NTC temperature real-time detection is realized, the over-temperature protection effect of the IGBT is achieved, and the detection circuit is simple, flexible, high in sampling precision and wide in application range.

In the above embodiment, the NTC thermistor is used for detecting the internal temperature of the IGBT, and as another embodiment, a PT100 thermistor or thermocouple may be used.

The utility model provides a pair of power module temperature system of patrolling and examining can realize the real-time detection to the inside temperature of a plurality of power module IGBT in the system, and circuit structure is simple, the precision is high, with low costs, nimble temperature of gathering multichannel temperature sensor, easily realizes detecting and protecting a plurality of power module's temperature. And the primary side and the secondary side of the frequency signal are isolated through the optical coupling isolation module, so that the interference caused by the electric connection is prevented.

The specific embodiments are given above, but the present invention is not limited to the described embodiments. The basic idea of the utility model lies in the above basic scheme, to the ordinary technical personnel in this field, according to the utility model discloses a teaching, design model, formula, the parameter of various deformations and do not need the creative work of cost. Variations, modifications, substitutions and alterations of the embodiments may be made without departing from the principles and spirit of the invention.

Claims

1. A power module temperature inspection system is characterized by comprising a voltage acquisition module, an inspection circuit module, a voltage-frequency conversion module and a control module; the voltage acquisition module comprises a plurality of voltage sampling circuits, and each voltage sampling circuit is respectively used for acquiring the temperatures of different power modules and outputting a voltage value corresponding to the temperature; the inspection circuit module comprises a plurality of inspection circuits which are in one-to-one correspondence with the voltage sampling circuits, each inspection circuit comprises an operational amplifier and a diode, the homodromous input end of the operational amplifier is connected with the output end of the corresponding voltage sampling circuit, the diode is connected in series with the output end of the operational amplifier, the cathode of the diode is connected with the output end of the operational amplifier, and the reverse input end of the operational amplifier is connected with the anode of the diode; the anodes of all the diodes are connected with the voltage-frequency conversion module so as to output the minimum voltage value in the voltage values output by each voltage acquisition module to the voltage-frequency conversion module, the voltage-frequency conversion module is used for performing voltage-frequency conversion, and the voltage-frequency conversion module is connected with the control module and is used for transmitting the converted frequency signals to the control module.

2. The power module temperature inspection system according to claim 1, wherein the voltage sampling circuit includes a thermistor and a voltage divider resistor arranged in series, and the voltage divider point of the thermistor and the voltage divider resistor is the output end of the voltage sampling circuit.

3. The power module temperature inspection system according to claim 2, wherein the voltage sampling circuit further includes a filter capacitor connected in parallel across the thermistor.

4. The power module temperature inspection system according to claim 1, wherein the voltage to frequency conversion module includes a voltage to frequency converter; the input end of the voltage-frequency converter is connected with the output end of the voltage acquisition module through the first RC filter circuit, and the frequency output end of the voltage-frequency converter is connected with the control module.

5. The power module temperature inspection system according to claim 1, further comprising an opto-isolator module, wherein the voltage-to-frequency conversion module is connected to the control module through the opto-isolator module; the optical coupler isolation module comprises an optical coupler, one end of the primary side of the optical coupler is connected with a first power supply through a first pull-up resistor, and the other end of the primary side of the optical coupler is connected with the output end of the voltage-frequency conversion module; one end of the optical coupler secondary side is connected with a second power supply, the other end of the optical coupler secondary side is connected with the control module, and the optical coupler secondary side is further connected with the second power supply through a second pull-up resistor.

6. The power module temperature inspection system according to claim 5, further comprising a filter module, wherein the filter module is a second RC filter circuit, and the other end of the secondary side of the optical coupler is connected with the control module through the second RC filter circuit.

7. The power module temperature inspection system according to any one of claims 1-6, wherein the control module is an FPGA.

8. The power module temperature inspection system according to claim 2, wherein the thermistor is an NTC resistor, PT100, or thermocouple.