IGBT junction temperature calibration system

Abstract

The embodiment of the present invention provides an IGBT junction temperature calibration system, which relates to the technical field of IGBT junction temperature calibration. The system includes: a main control module, a temperature acquisition module, an IGBT drive module, a power sampling module and a current detection control module; the main control module is electrically connected to the temperature acquisition module, the IGBT drive module, the power sampling module and the current detection control module respectively, the power sampling module is electrically connected to the current detection control module, and the IGBT drive module and the power sampling module are connected to the IGBT respectively; the present invention controls the working state of the IGBT to switch between working in a linear region and working in a saturation region, and collects different junction temperature calibration parameters when controlling the IGBT to work in different working states, thereby realizing automatic control of the entire process of the IGBT junction temperature calibration test, which is conducive to standardizing the measurement of the IGBT junction temperature calibration, and at the same time makes the test results more accurate and the test efficiency higher.

Description

Technical Field

[0001] The invention relates to the technical field of IGBT junction temperature calibration, and in particular to an IGBT junction temperature calibration system. Background Art

[0002] In power electronics applications, IGBTs mainly work in a switching state and periodically experience various static and dynamic states, which will cause energy loss, heat generation of power loss devices, and fluctuations in the IGBT junction temperature. Due to the material and packaging of the IGBT chip, its junction temperature is not allowed to exceed the maximum allowable range. In practical applications, it is necessary to accurately obtain the IGBT junction temperature to ensure the normal operation of the controller.

[0003] The existing junction temperature detection methods mainly include the temperature-sensitive parameter method. Using the temperature-sensitive parameter method, it can be known that when the IGBT conducts a small current Im=100mA, there is a good linear relationship between the saturation voltage drop and the junction temperature. However, the current of the IGBT chip during actual operation is much greater than 100mA. Therefore, it is difficult to measure the IGBT junction temperature through the saturation voltage drop in actual work, and adding a 100mA constant current source in actual work has great design difficulties, and will increase the cost and reduce the safety of the system. Therefore, how to provide an IGBT junction temperature calibration system that can calibrate the working junction temperature of the IGBT to improve the accuracy and efficiency of the IGBT junction temperature calibration is a major technical problem that needs to be solved urgently by those skilled in the art. Summary of the invention

[0004] The purpose of the embodiments of the present invention is to provide an IGBT junction temperature calibration system to solve the current problem of low accuracy and efficiency of IGBT junction temperature calibration.

[0005] In order to achieve the above object, the present invention provides an IGBT junction temperature calibration system, which is used to calibrate the junction temperature of the IGBT, comprising:

[0006] A main control module, a temperature acquisition module, an IGBT driving module, a power sampling module and a current detection control module; the main control module is connected to the temperature acquisition module, the IGBT driving module, the power sampling module and the current detection control module respectively; the IGBT driving module, the power sampling module and the current detection control module are connected to the IGBT respectively;

[0007] The power sampling module is used to collect a first on-current value and a first on-voltage value between the collector and the emitter of the IGBT when the IGBT operates in a linear region, and to collect a second on-voltage value between the collector and the emitter of the IGBT when the IGBT operates in a saturation region;

[0008] The temperature acquisition module is used to acquire the temperature value of the IGBT;

[0009] The main control module is used for:

[0010] Control the current detection control module to apply a conduction current to the IGBT, control the IGBT driving module to apply a first driving voltage to the IGBT to control the IGBT to operate in a linear region, and control the IGBT driving module to apply a second driving voltage to the IGBT to control the IGBT to operate in a saturation region; and

[0011] The power loss of the IGBT is calculated according to the first on-current value and the first on-voltage value, and the corresponding relationship between the power loss of the IGBT and the temperature value of the IGBT is calibrated according to the second on-voltage value, the temperature value of the IGBT and the power loss of the IGBT.

[0012] Optionally, the main control module includes a central processing unit and a core logic control unit;

[0013] The power sampling module includes a current sampling unit, a voltage sampling unit, a first ADC unit and a second ADC unit;

[0014] The current detection control module includes a current control unit, a current power unit and a DAC unit;

[0015] The central processing unit is connected to the core logic control unit, the first ADC unit, the second ADC unit, the DAC unit and the temperature acquisition module respectively; the first ADC unit is connected to the current sampling unit, the second ADC unit is connected to the voltage sampling unit, the DAC unit is connected to the current control unit, the core logic control unit is connected to the IGBT driving module, the current control unit and the voltage sampling unit respectively; the current sampling unit and the current control unit are connected to the current power unit respectively; the current power unit and the voltage sampling unit are connected to the IGBT respectively.

[0016] Optionally, the temperature acquisition module includes: a first temperature acquisition submodule, a second temperature acquisition submodule and a third ADC unit;

[0017] The first temperature acquisition submodule and the second temperature acquisition submodule are respectively connected to the third ADC unit, and the third ADC unit is connected to the central processing unit;

[0018] The first temperature acquisition submodule is used to acquire the temperature value of the temperature acquisition thermocouple arranged on the IGBT as the temperature value of the IGBT, and the second temperature acquisition submodule is used to acquire the temperature value of the thermistor inside the IGBT as the temperature value of the IGBT;

[0019] The first temperature acquisition submodule includes: a temperature sensor, a first amplification unit and a first digital isolation unit;

[0020] The output end of the temperature sensor is connected to the input end of the first amplifying unit, the output end of the first amplifying unit is connected to the input end of the third ADC unit, the output end of the third ADC unit is connected to the input end of the first digital isolation unit, and the output end of the first digital isolation unit is connected to the input end of the central processing unit;

[0021] The temperature sensor is used to collect the temperature value of the temperature collection thermocouple;

[0022] The second temperature acquisition submodule includes: a second amplification unit and a second digital isolation unit;

[0023] The input end of the second amplifying unit is connected to the thermistor to collect the voltage value of the thermistor, the output end of the second amplifying unit is connected to the input end of the third ADC unit, the output end of the third ADC unit is connected to the input end of the second digital isolation unit, and the output end of the second digital isolation unit is connected to the input end of the central processing unit.

[0024] Optionally, the core logic control unit includes a trigger circuit, and the trigger circuit includes:

[0025] A first delay trigger circuit, a second delay trigger circuit and a third delay trigger circuit;

[0026] The input end of the first delay trigger circuit is connected to the output end of the central processing unit, and the output end of the first delay trigger circuit is connected to the input end of the second delay trigger circuit and the input end of the current control unit;

[0027] The output end of the second delay trigger circuit is connected to the input end of the third delay trigger circuit and the input end of the IGBT driving module;

[0028] The output end of the third delay trigger circuit is connected to the input end of the voltage sampling unit;

[0029] The output end of the central processing unit outputs a fixed-frequency PWM control signal to trigger the first delay trigger circuit to generate a first control signal, trigger the second delay trigger circuit to generate a second control signal, and trigger the third delay trigger circuit to generate a third control signal, so as to control the current control unit to apply a conduction current to the IGBT, control the IGBT drive module to apply the second drive voltage to the IGBT, and control the voltage sampling unit to collect the second conduction voltage value according to a set timing.

[0030] Optionally, the first delay trigger circuit includes a first monostable multivibrator, the second delay trigger circuit includes a second monostable multivibrator, and the third delay trigger circuit includes a third monostable multivibrator;

[0031] The first falling edge trigger end of the first monostable multivibrator is connected to the output end of the central processing unit, the first forward output end of the first monostable multivibrator is connected to the input end of the current control unit and the first rising edge trigger end of the second monostable multivibrator, the first forward output end of the second monostable multivibrator is connected to the second falling edge trigger end of the second monostable multivibrator, the second forward output end of the second monostable multivibrator is connected to the input end of the IGBT driving module and the first rising edge trigger end of the third monostable multivibrator, the first forward output end of the third monostable multivibrator is connected to the second falling edge trigger end of the third monostable multivibrator, and the second forward output end of the third monostable multivibrator is connected to the input end of the voltage sampling unit.

[0032] Optionally, the current power unit includes a current sampling resistor and a power MOS tube, and the current sampling resistor and the power MOS tube are connected in series on a bus;

[0033] The current control unit comprises:

[0034] A first selection switch, a voltage follower circuit and a push-pull circuit, wherein the output end of the DAC unit is connected to the channel selection end of the first selection switch, the input end of the first selection switch is connected to the output end of the first delay trigger circuit, the output end of the first selection switch is connected to the input end of the voltage follower circuit, the output end of the voltage follower circuit is connected to the input end of the push-pull circuit, and the output end of the push-pull circuit is connected to the gate of the power MOS tube;

[0035] The first selection switch is used to select the channel selection end of the first selection switch and the output end of the first selection switch after receiving the first control signal, the voltage follower circuit is used to input the voltage output by the output end of the DAC unit into the push-pull circuit, and the push-pull circuit is used to apply the input voltage to the gate of the power MOS tube after voltage regulation to generate a constant current flowing through the bus, and apply the generated constant current between the emitter and collector of the IGBT through the bus.

[0036] Optionally, the current control unit further includes a voltage feedback circuit;

[0037] The input end of the voltage feedback circuit is connected to the two ends of the current sampling resistor, and the output end of the voltage feedback circuit is connected to the input end of the voltage follower circuit. The voltage feedback circuit is used to feed back the voltage across the current sampling resistor to the voltage follower circuit so that the voltage follower circuit adjusts the output of the voltage follower circuit according to the voltage fed back by the voltage feedback circuit until a stable state is reached.

[0038] Optionally, the IGBT driving module includes:

[0039] A second selection switch and a voltage switching circuit;

[0040] The input end of the second gate switch is connected to the output end of the second delay trigger circuit, the first channel selection end of the second gate switch is grounded, the second channel selection end of the second gate switch is in contact with the voltage, the output end of the second gate switch is connected to the voltage switching circuit, and the gate of the IGBT is connected to the first voltage source and the second voltage source through the voltage switching circuit;

[0041] The second gating switch is used to gating the first channel selection end of the second gating switch and the output end of the second gating switch before receiving the second control signal, and gating the second channel selection end of the second gating switch and the output end of the second gating switch after receiving the second control signal;

[0042] The voltage switching circuit is used for switching the first voltage source to apply the first driving voltage to the gate of the IGBT after the first channel selection terminal of the second selection switch and the output terminal of the second selection switch are selected, and for triggering the voltage switching circuit to switch the second voltage source to apply the second driving voltage to the gate of the IGBT after the second channel selection terminal of the second selection switch and the output terminal of the second selection switch are selected.

[0043] Optionally, the voltage switching circuit includes: an amplifying subcircuit and a switching subcircuit;

[0044] The input end of the amplifier subcircuit is connected to the output end of the second gate switch, the output end of the amplifier subcircuit is connected to the control end of the switch subcircuit, the gate of the IGBT is connected to the second voltage source through the switch subcircuit, and the gate of the IGBT is connected to the first voltage source through the switch subcircuit;

[0045] The amplifying sub-circuit is used for controlling the switching sub-circuit to switch the first voltage source to apply the first driving voltage to the gate of the IGBT after the first channel selection terminal of the second gating switch and the output terminal of the second gating switch are gated; and

[0046] After the second channel selection terminal of the second gate switch and the output terminal of the second gate switch are gated, the trigger voltage is amplified to control the switch subcircuit to switch the second voltage source to apply the second driving voltage to the gate of the IGBT.

[0047] Optionally, the voltage sampling unit includes: a voltage storage circuit, a third selection switch, a voltage holding circuit and a voltage acquisition circuit;

[0048] The output ends of the voltage acquisition circuit and the voltage storage circuit are respectively connected to the input end of the second ADC unit, the input end of the voltage storage circuit is connected to the output end of the third gating switch, the first channel selection end of the third gating switch is suspended, the second channel selection end of the third gating switch is connected to the output end of the voltage holding circuit, and the input end of the voltage holding circuit is connected to the output end of the voltage acquisition circuit;

[0049] The voltage acquisition circuit is used to acquire the on-voltage value of the IGBT, and the third selection switch is used to select the output end of the third selection switch and the second channel selection end of the third selection switch after receiving the third control signal, so that the voltage holding circuit can store the collected on-voltage value of the IGBT in the form of equivalent electrical energy to the voltage storage circuit.

[0050] The above technical solution of the present invention controls the working state of the IGBT to switch between working in the linear region and working in the saturation region, and collects different junction temperature calibration parameters when controlling the IGBT to work in different working states, thereby realizing automatic control of the entire process of the IGBT junction temperature calibration test, which is beneficial to standardizing the measurement of the IGBT junction temperature calibration, and at the same time makes the test results more accurate and the test efficiency higher.

[0051] Other features and advantages of the embodiments of the present invention will be described in detail in the following detailed description. BRIEF DESCRIPTION OF THE DRAWINGS

[0052] The accompanying drawings are used to provide a further understanding of the embodiments of the present invention and constitute a part of the specification. Together with the following specific embodiments, they are used to explain the embodiments of the present invention, but do not constitute a limitation on the embodiments of the present invention. In the accompanying drawings:

[0053] Figure 1 It is a schematic diagram of the system structure of an IGBT junction temperature calibration system provided by a preferred embodiment of the present invention;

[0054] Figure 2 It is a schematic diagram of the structure of a temperature acquisition module provided in a preferred embodiment of the present invention;

[0055] Figure 3a to Figure 3c It is a circuit diagram of a core logic control unit provided by a preferred embodiment of the present invention;

[0056] Figure 4a to Figure 4c is a circuit diagram of a current control unit provided in a preferred embodiment of the present invention;

[0057] Figure 5a to Figure 5c is a circuit diagram of an IGBT driving module provided in a preferred embodiment of the present invention;

[0058] Figure 6a to Figure 6c It is a circuit diagram of a voltage sampling unit provided in a preferred embodiment of the present invention. DETAILED DESCRIPTION

[0059] The specific implementation of the present invention is described in detail below in conjunction with the accompanying drawings. It should be understood that the specific implementation described here is only used to illustrate and explain the present invention, and is not used to limit the present invention.

[0060] like Figure 1 As shown, this embodiment provides an IGBT junction temperature calibration system, which is used to calibrate the junction temperature of the IGBT, including:

[0061] Main control module, temperature acquisition module, IGBT drive module, power sampling module and current detection control module; the main control module is connected with the temperature acquisition module, IGBT drive module, power sampling module and current detection control module respectively; the IGBT drive module, power sampling module and current detection control module are connected with the IGBT respectively;

[0062] The power sampling module is used to collect a first on-current value and a first on-voltage value between the collector and the emitter of the IGBT when the IGBT works in a linear region, and to collect a second on-voltage value between the collector and the emitter of the IGBT when the IGBT works in a saturation region;

[0063] The temperature acquisition module is used to collect the temperature value of IGBT;

[0064] The main control module is used to:

[0065] Control the current detection control module to apply a conduction current to the IGBT, control the IGBT driving module to apply a first driving voltage to the IGBT to control the IGBT to operate in a linear region, and control the IGBT driving module to apply a second driving voltage to the IGBT to control the IGBT to operate in a saturation region; and

[0066] The power loss of the IGBT is calculated according to the first on-current value and the first on-voltage value, and the corresponding relationship between the power loss of the IGBT and the temperature value of the IGBT is calibrated according to the second on-voltage value, the temperature value of the IGBT and the power loss of the IGBT.

[0067] In this way, the junction temperature calibration system provided in this embodiment can control the working state of the IGBT to switch between working in the linear region and working in the saturation region, and collect different junction temperature calibration parameters when controlling the IGBT to work in different working states, thereby realizing automatic control of the entire process of IGBT junction temperature calibration test, which is conducive to standardizing the measurement of IGBT junction temperature calibration, while making the test results more accurate and the test efficiency higher.

[0068] Specifically, the main control module communicates with the IGBT driver module, the power sampling module and the temperature acquisition module through the SPI communication module. At the same time, the main control module is also connected to the host computer through the UART module to communicate with the host computer for data exchange. Among them, the main control module, the temperature acquisition module, the IGBT driver module, the power sampling module and the current detection control module can be integrated on the same circuit board or can be set separately. The IGBT driver module accepts the control of the main control module to switch the driving voltage applied to the IGBT gate to control the IGBT to work in the linear region or the saturation region. When the IGBT driver module does not control the gate voltage of the IGBT, the IGBT works in the linear region. When the IGBT driver module switches to apply a voltage of 15V to the gate of the IGBT, the IGBT works in the saturation region, so that the IGBT can be controlled to work in different working areas, and the junction temperature calibration parameters such as saturation voltage drop, IGBT temperature and other parameters under different working states of the IGBT can be collected, and then the main control module can automatically calibrate the junction temperature of the IGBT according to the collected junction temperature calibration parameters. In order to further solve the problem that the existing IGBT junction temperature calibration has certain difficulties in measuring the IGBT junction temperature through the saturation voltage drop in actual work, resulting in inaccurate IGBT junction temperature calibration, this embodiment calculates the power loss of the IGBT when the IGBT controls the IGBT to work in the linear region, and switches the IGBT to work in the saturation region after obtaining the power loss of the IGBT and collects the temperature value and on-voltage value of the IGBT, and then calibrates the relationship between the power loss of the IGBT and the saturation voltage drop and the relationship between the saturation voltage drop of the IGBT and the temperature. The relationship between the power loss of the IGBT and the temperature can be calibrated. Therefore, in actual applications, it is only necessary to detect the power loss of the IGBT to obtain the corresponding junction temperature, without adding additional detection circuits in the control system, thereby reducing the cost of the control system and effectively solving the problem of low junction temperature calibration accuracy due to the inability to accurately obtain the IGBT saturation voltage drop in actual applications.

[0069] The main control module includes a central processing unit and a core logic control unit; the power sampling module includes a current sampling unit, a voltage sampling unit, a first ADC unit and a second ADC unit; the current detection control module includes a current control unit, a current power unit and a DAC unit;

[0070] The central processing unit is respectively connected to the core logic control unit, the first ADC unit, the second ADC unit, the DAC unit and the temperature acquisition module, the first ADC unit is connected to the current sampling unit, the second ADC unit is connected to the voltage sampling unit, the DAC unit is connected to the current control unit, the core logic control unit is respectively connected to the IGBT drive module, the current control unit and the voltage sampling unit, the current sampling unit and the current control unit are respectively connected to the current power unit, and the current power unit and the voltage sampling unit are respectively connected to the IGBT. Among them, the central processing unit is an MCU, and in this embodiment, an MCU of model PIC32MZ1024EFE064-IPT is used as the central processing unit of this system.

[0071] In this embodiment, a complete working process of the junction temperature calibration system includes: in the first stage, the junction temperature calibration system operates in a steady state at a relatively high power; in the second stage, current and voltage are switched to perform IGBT saturation conduction voltage drop sampling.

[0072] The first stage: provide the IGBT with an appropriate bus voltage, and the MCU controls the IGBT driver module to switch the bus voltage through the core logic control unit to provide the first driving voltage for the gate of the IGBT so that the IGBT works in the linear region; the MCU communicates with the current control unit through SPI via the DAC unit to control the current output by the current power unit, and at the same time, the current sampling unit collects the current flowing through the IGBT and feeds the collected current value back to the MCU through the first ADC unit through SPI communication to control the output current sharing; the MCU collects the first on-current value flowing between the emitter and collector of the IGBT through the current sampling unit and collects the first on-voltage value between the emitter and collector of the IGBT through the voltage sampling unit, and the current power loss of the IGBT can be calculated through the first on-current value and the first on-voltage value.

[0073] The second stage: the MCU provides a PWM control signal with a fixed frequency and duty cycle to the core logic control unit. In this embodiment, the frequency of the PWM control signal is 10 Hz. At each rising edge of the PWM control signal, the core logic control unit first triggers the control current control unit to adjust the output current to 100 mA, thereby applying a 100 mA conduction current to the IGBT. After a preset small delay, the core logic control unit triggers the control IGBT drive module to switch the drive voltage applied to the IGBT gate to a second drive voltage of +15 V, so that the IGBT is in a saturated conduction state. After a preset small delay, the core logic control unit triggers the control voltage sampling unit to sample the voltage of the IGBT, and obtains the second conduction voltage value of the IGBT, that is, the saturation voltage drop of the IGBT, and then transmits the second conduction voltage value to the MCU through the second ADC unit via SPI communication, so as to obtain the saturation voltage drop under the current power loss of the IGBT. At the same time, the MCU collects the temperature value of the IGBT through the temperature acquisition module to obtain the junction temperature corresponding to the current saturation voltage drop of the IGBT, thereby obtaining the junction temperature corresponding to the current power loss of the IGBT.

[0074] By collecting and calculating the power loss, saturation voltage drop and junction temperature of the IGBT under different ambient temperatures through the above control process, the automatic calibration of the corresponding relationship between the power loss and junction temperature of the IGBT can be achieved.

[0075] In this embodiment, the temperature acquisition of the IGBT includes acquiring the temperature of the IGBT by a thermocouple disposed on the IGBT substrate and acquiring the voltage value of the NTC thermistor integrated inside the IGBT to acquire the temperature of the IGBT. Therefore, the temperature acquisition module includes:

[0076] The first temperature acquisition submodule, the second temperature acquisition submodule and the third ADC unit; the first temperature acquisition submodule and the second temperature acquisition submodule are respectively connected to the third ADC unit, and the third ADC unit is connected to the central processing unit; the first temperature acquisition submodule is used to acquire the temperature value of the temperature acquisition thermocouple set on the IGBT as the temperature value of the IGBT, and the second temperature acquisition submodule is used to acquire the temperature value of the thermistor inside the IGBT as the temperature value of the IGBT.

[0077] like Figure 2As shown, the first temperature acquisition submodule includes: a temperature sensor, a first amplifying unit and a first digital isolation unit; the output end of the temperature sensor is connected to the input end of the first amplifying unit, the output end of the first amplifying unit is connected to the input end of the third ADC unit, the output end of the third ADC unit is connected to the input end of the first digital isolation unit, and the output end of the first digital isolation unit is connected to the input end through SPI communication; the temperature sensor is used to collect the temperature value of the temperature collection thermocouple, and the temperature sensor collects the electrical signal at the corresponding temperature of the temperature collection thermocouple through the connector.

[0078] The second temperature acquisition submodule includes: a second amplifying unit and a second digital isolation unit; the input end of the second amplifying unit is connected to the thermistor through a connector to collect the voltage value of the thermistor, and at the same time, the thermistor is sampled and powered by a high-precision reference power supply, the output end of the second amplifying unit is connected to the input end of the third ADC unit, the output end of the third ADC unit is connected to the input end of the second digital isolation unit, the output end of the second digital isolation unit is connected to the input end of the MCU through SPI communication, and the third ADC unit converts the collected analog quantity representing the temperature value of the temperature acquisition thermocouple and the analog quantity representing the temperature value of the thermistor into digital quantity and sends it to the MCU through SPI communication.

[0079] Among them, the first amplification unit and the second amplification unit are operational amplifiers of model LT1221CS8, the temperature sensor is AD8495CRMZ, the third ADC unit is ADS8330IBPW, the first digital isolation unit is ADuM140E1BRZ, and the second digital isolation unit is ADuM225N0BRIZ. The first digital isolation unit and the second digital isolation unit are used to isolate the MCU side from the temperature acquisition side to protect the MCU. In this way, the junction temperature calibration system of this embodiment can realize the acquisition of the temperature of the IGBT through the temperature acquisition thermocouple or the NTC thermistor inside the IGBT, and can accurately acquire the temperature of IGBTs of different models.

[0080] The core logic control unit includes a trigger circuit, and the trigger circuit includes:

[0081] A first delay trigger circuit, a second delay trigger circuit and a third delay trigger circuit; the input end of the first delay trigger circuit is connected to the output end of the central processing unit, the output end of the first delay trigger circuit is connected to the input end of the second delay trigger circuit and the input end of the current control unit; the output end of the second delay trigger circuit is connected to the input end of the third delay trigger circuit and the input end of the IGBT driving module; the output end of the third delay trigger circuit is connected to the input end of the voltage sampling unit;

[0082] The output end of the central processing unit outputs a fixed-frequency PWM control signal Trigger source to trigger the first delay trigger circuit to generate a first control signal cur source ctr, trigger the second delay trigger circuit to generate a second control signal gate drive ctr, and trigger the third delay trigger circuit to generate a third control signal vce sample ctr, so as to control the current control unit to apply a conduction current to the IGBT, control the IGBT drive module to apply a second drive voltage to the IGBT, and control the voltage sampling unit to collect the second conduction voltage value according to the set timing, and then at the rising edge of the PWM control signal, the first delay trigger circuit generates a first control signal to trigger the control current control unit to adjust the output current to 100mA, after a preset delay, the first delay trigger circuit triggers the second delay trigger circuit to generate a second control signal to trigger the control IGBT drive module to switch the drive voltage applied to the gate of the IGBT to a second drive voltage of +15V, so that the IGBT is in a saturated conduction state, and after a preset delay, the second delay trigger circuit triggers the third delay trigger circuit to generate a third control signal to trigger the control voltage sampling unit to sample the voltage of the IGBT.

[0083] like Figure 3a to Figure 3c As shown, in this embodiment, the core logic control unit also includes:

[0084] A first switch JP1000, a second switch JP1001 and a control signal generating circuit; the output end of the central processing unit is connected to the input end of the first delay trigger circuit through the first switch JP1000, and the output end of the control signal generating circuit is connected to the input end of the first delay trigger circuit through the second switch JP1001; the output end of the control signal generating circuit outputs a PWM control signal with the same fixed frequency as the output of the central processing unit to trigger the first delay trigger circuit to generate a first control signal, trigger the second delay trigger circuit to generate a second control signal and trigger the third delay trigger circuit to generate a third control signal, so as to control the current control unit to apply a conduction current to the IGBT, control the IGBT driving module to apply a second driving voltage to the IGBT and control the voltage sampling unit to collect the second conduction voltage value according to the set timing; the first switch JP1000 and the second switch JP1001 act asynchronously, and then in actual applications, the first switch JP1000 and the second switch JP1001 can be used to switch whether the PWM control signal is output by the MCU or the control signal generating circuit. Among them, the control signal generating circuit is composed of a single Schmitt trigger U1002 and peripheral resistors AR1000, R1000 and capacitors C1000, C1001.

[0085] The first delay trigger circuit includes a first monostable multivibrator U1006, the second delay trigger circuit includes a second monostable multivibrator U1009, and the third delay trigger circuit includes a third monostable multivibrator U1017; the first falling edge trigger terminal 1 of the first monostable multivibrator U1006 The first switch JP1000 is connected to the output end of the central processing unit, the first positive output end 1Q of the first monostable multivibrator U1006 is connected to the input end of the current control unit and the first rising edge trigger end 1B of the second monostable multivibrator U1009, and the first positive output end 1Q of the second monostable multivibrator U1009 is connected to the second falling edge trigger end 1B of the second monostable multivibrator U1009.

[0086] 2 The second positive output terminal of the second monostable multivibrator U1009 is connected to the input terminal of the IGBT drive module and the first rising edge trigger terminal 1B of the third monostable multivibrator U1017, and the first positive output terminal 1Q of the third monostable multivibrator U1017 is connected to the second falling edge trigger terminal 2 The second positive output terminal of the third monostable multivibrator U1017 is connected to the input terminal of the voltage sampling unit. Among them, the first monostable multivibrator U1006, the second monostable multivibrator U1009 and the third monostable multivibrator U1017 adopt a monostable multivibrator of model SN74LV123ATPWRQ1, and the delay working time is adjusted by matching the external capacitor and resistor of the monostable multivibrator. The specific circuit of the delay control is a typical application of SN74LV123ATPWRQ1, which will not be repeated here.

[0087] When calculating the power loss and collecting the saturation voltage drop of the IGBT, the current control unit needs to control the output current to be constant current. Therefore, the current power unit includes a current sampling resistor and a power MOS tube. The current sampling resistor and the power MOS tube are connected in series on the bus. Figure 4a to Figure 4c As shown, the current control unit includes:

[0088] The first selection switch U2007, the voltage follower circuit and the push-pull circuit, the output end of the DAC unit U2004 is connected to the channel selection end of the first selection switch U2007, the input end IN of the first selection switch U2007 is connected to the output end of the first delay trigger circuit, that is, the first positive output end 1Q of the first monostable multivibrator U1006, the output end D of the first selection switch U2007 is connected to the input end of the voltage follower circuit, the output end of the voltage follower circuit is connected to the input end of the push-pull circuit, and the output end of the push-pull circuit is connected to the gate of the power MOS tube through the connector CN2001; the first selection switch U2007 is used to receive the first After a control signal is generated, the channel selection end of the first selection switch U2007 and the output end of the first selection switch U2007 are selected. The voltage follower circuit is used to input the voltage output by the output end of the DAC unit U2004 into the push-pull circuit. The push-pull circuit is used to apply the input voltage to the gate of the power MOS tube after voltage regulation to generate a constant current flowing through the bus through the current sampling resistor. In this way, the power MOS tube, the current sampling resistor and the current control unit constitute a constant current source with optional output, and the constant current output by the source is applied between the emitter and the collector of the IGBT through the bus. The circuit structure of the push-pull circuit is a prior art and will not be repeated here.

[0089] In order to ensure that the current output by the current control unit and the current power unit is constant, the current control unit also includes a voltage feedback circuit, the input end of the voltage feedback circuit is connected to the two ends of the current sampling resistor, and the output end of the voltage feedback circuit is connected to the input end of the voltage follower circuit. The voltage feedback circuit is used to feed back the voltage across the current sampling resistor to the voltage follower circuit so that the voltage follower circuit adjusts the output of the voltage follower circuit according to the voltage feedback circuit until a stable state is reached.

[0090] In this embodiment, the first output terminal VOUTA of the DAC unit U2004 is connected to the first channel selection terminal SA of the first selection switch U2007, and the second output terminal VOUTB of the DAC unit U2004 is connected to the second channel selection terminal SB of the first selection switch U2007, wherein the first output terminal VOUTA and the second output terminal VOUTB of the DAC unit U2004 output different voltages respectively, so that when the first selection switch U2007 selects its first channel selection terminal SA, the current control unit outputs a large current, and when the first selection switch U2007 selects its second channel selection terminal SB, the current control unit outputs a small current of 100mA.

[0091] Among them, the voltage follower circuit includes a first operational amplifier U2011A and a second operational amplifier U2013A, and the voltage feedback circuit includes a third operational amplifier U2018A. Among them, the first operational amplifier U2011A and the second operational amplifier U2013A and their corresponding peripheral circuits constitute a voltage follower circuit. The specific structure of the voltage follower circuit of this embodiment can be implemented using the existing voltage follower circuit structure, which will not be repeated here. The output terminal D of the first selection switch U2007 is connected to the positive input terminal of the first operational amplifier U2011A, the reverse input terminal of the first operational amplifier U2011A is connected to the output terminal of the first operational amplifier U2011 and is connected to the positive input terminal of the second operational amplifier U2013A through the resistor R2005, the output terminal of the second operational amplifier U2013A is connected to the reverse input terminal of the second operational amplifier U2013A through the peripheral circuit and is connected to the output terminal of the third operational amplifier U2018A, the output terminal of the third operational amplifier U2018A is connected to the reverse output terminal of the third operational amplifier U2018A through the peripheral circuit and is connected to the first terminal of the current sampling resistor through the connector CN2001, and the positive input terminal of the third operational amplifier U2018A is connected to the second terminal of the current sampling resistor through the connector CN2001.

[0092] When the input end of the first selection switch U2007 is at a low level, the first channel selection end SA and the output end D are selected, and when the input end of the first selection switch U2007 is at a high level, the second channel selection end SB and the output end D are selected. In this embodiment, when the IGBT is controlled to work in the linear region, the first selection switch U2007 selects the first channel selection end SA and the output end D. When the IGBT is controlled to work in the saturation region, that is, after the input end of the first selection switch U2007 receives the first control signal, the input end of the first selection switch U2007 is at a high level, and at this time, it selects the second channel selection end SB and the output end D. In this way, the first selection switch U2007 can be used to select the current output by the current control unit through the current power unit to be a large current or an output voltage corresponding to the sampling current of 100mA, and the voltage output by the DAC unit U2004 is input to the push-pull circuit through the first operational amplifier U2011A and the second operational amplifier U2013A. The push-pull circuit adjusts the voltage and applies it to the gate of the power MOS tube. The current flowing through the power MOS tube increases, and then the current flowing through the current sampling resistor increases. The voltage across the current sampling resistor increases, resulting in an increase in the voltage of the positive input terminal and the reverse input terminal of the third operational amplifier U2018A, thereby increasing the output terminal voltage of the third operational amplifier U2018A, and then causing the reverse input terminal voltage of the second operational amplifier U2013A to increase. According to the virtual short principle, the positive input terminal and the reverse input terminal of the second operational amplifier U2013A form an equipotential, and then the constant current source circuit composed of the DAC unit, the current control unit and the current power unit forms a steady state, and the circuit works in a steady state and outputs a constant current.

[0093] The IGBT driver module is used to switch the drive voltage applied to the IGBT gate. Figure 5a to Figure 5cAs shown, the IGBT driving module includes: a second selection switch U3016 and a voltage switching circuit; the input terminal IN of the second selection switch U3016 is connected to the output terminal of the second delay trigger circuit through the digital isolator U3011, the first channel selection terminal SA of the second selection switch U3016 is grounded, the second channel selection terminal SB of the second selection switch U3016 contacts the trigger voltage source UH_REF, and the trigger voltage source UH_REF outputs a reference voltage as a trigger voltage; the output terminal D of the second selection switch U3016 is connected to the voltage switching circuit, and the gate of the IGBT is connected to the first voltage source and the second voltage source through the voltage switching circuit; the second selection switch U3016 is used to select the second selection before receiving the second control signal. The first channel selection terminal SA of the second selection switch U3016 and the output terminal of the second selection switch U3016, and the second channel selection terminal SB of the second selection switch U3016 and the output terminal of the second selection switch U3016 are selected after receiving the second control signal; the voltage switching circuit is used to switch the first voltage source to apply the first driving voltage to the gate of the IGBT after the first channel selection terminal SA of the second selection switch U3016 and the output terminal D of the second selection switch U3016 are selected, and to switch the second voltage source to apply the second driving voltage to the gate of the IGBT through the trigger voltage triggering voltage switching circuit after the second channel selection terminal SB of the second selection switch U3016 and the output terminal D of the second selection switch U3016 are selected.

[0094] Among them, the voltage switching circuit includes: an amplifying sub-circuit and a switching sub-circuit; the amplifying sub-circuit includes a fourth operational amplifier U3015A and a first diode D3005, and the switching sub-circuit includes a second diode D3006, a first resistor R3017, a second resistor R3021, a third resistor R3022, a fourth resistor R3024, a fifth resistor R3025, a sixth resistor R3027, a seventh resistor R3028, a first capacitor C3057, a first transistor Q3000 and a second transistor Q3001, wherein the first transistor Q3000 is an NPN transistor, and the second transistor Q3001 is a PNP transistor.

[0095] The output terminal D of the second selection switch U3016 is connected to the positive input terminal of the fourth operational amplifier U3015A, the output terminal D of the fourth operational amplifier U3015A is connected to the first end of the second resistor R3021, the second end of the second resistor R3021 is connected to the base of the first transistor Q3000, the collector of the first transistor Q3000 is connected to the base of the second transistor Q3001 and connected to the second end of the fourth resistor R3024, the first end of the fourth resistor R3024 is connected to the second voltage source 30P, the first end of the fifth resistor R3025 is connected to the emitter of the first transistor Q3000, and the second end of the fifth resistor R3025 is grounded; the emitter of the second transistor Q3001 is connected to the second voltage source 30P, the second end of the first capacitor C3057 is connected to the second end of the third resistor R3022 and connected to the collector of the second transistor Q3001, the first capacitor C30 The first end of 57 is connected to the first end of the third resistor R3022 and connected to the anode of the first diode D3005, the anode of the first diode D3005 is connected to the negative input terminal of the fourth operational amplifier U3015A, the cathode of the first diode D3005 is connected to the output terminal of the fourth operational amplifier U3015A and connected to the first end of the second resistor R3021, the negative input terminal of the fourth operational amplifier U3015A is connected to the first resistor R3017 and grounded; the collector of the second transistor Q3001 is connected to the second end of the sixth resistor R3027 and the first end of the seventh resistor R3028 and connected to the gate of the IGBT, the first end of the sixth resistor R3027 is connected to the cathode of the second diode D3006, the anode of the second diode D3006 is connected to the collector of the IGBT, the second end of the seventh resistor R3028 is grounded, and the collector and emitter of the IGBT are connected to the first voltage source. In order to maintain the gate voltage of the IGBT at a fixed level, the gate of the IGBT is also connected to the cathode of the Zener diode D3007, and the anode of the Zener diode D3007 is grounded.

[0096] When the IGBT works in the linear region, the first channel selection terminal SA and the output terminal D of the second selection switch U3016 are selected. At this time, the gate voltage of the IGBT is controlled by the first voltage source. The voltage output by the first voltage source, that is, the bus voltage, is divided by the second diode D3006, the sixth resistor R3027 and the seventh resistor R3028 to provide a first driving voltage for the gate of the IGBT, so that the IGBT works in the linear region. At the same time, the gate voltage of the IGBT acts on the inverting resistor of the fourth operational amplifier U3015A through the third resistor R3022, the first capacitor C3057 and the first resistor R3017. To the input end, and since the first channel selection terminal SA of the second selection switch U3016 is grounded, the output of the fourth operational amplifier U3015A is low. In this embodiment, due to the action of the first diode D3005, the output of the fourth operational amplifier U3015A is maintained at -0.7V, so that the first transistor Q3000 and the second transistor Q3001 are cut off, ensuring that the gate voltage of the IGBT is only controlled by the first voltage source at this time. At the same time, it can effectively ensure that the circuit output can quickly switch to a steady state after switching the driving voltage applied to the gate of the IGBT, thereby reducing the loop response time.

[0097] When the input terminal IN of the second selection switch U3016 receives the second control signal, the second channel selection terminal SB and the output terminal D of the second selection switch U3016 are selected, and the positive input terminal of the fourth operational amplifier U3015A is turned on with the trigger voltage source UH_REF. The trigger voltage source UH_REF applies a fixed voltage of 1.5V to the positive input terminal of the fourth operational amplifier U3015A. At this time, the voltage of the positive input terminal of the fourth operational amplifier U3015A is greater than the voltage of the reverse input terminal. The output terminal of the fourth operational amplifier U3015A outputs a high level to turn on the first transistor Q3000. At this time, the base of the second transistor Q3001 is at a low level, then the second transistor Q3001 is turned on, and the gate of the IGBT is turned on with the second voltage source 30P. The second voltage source 30P outputs a 24V voltage which, after voltage division, provides a second driving voltage of 15V for the gate of the IGBT. According to the virtual short principle, the voltage at the forward input terminal and the voltage at the reverse input terminal of the fourth operational amplifier U3015A will eventually form an equal potential, and the gate voltage feedback of the IGBT acts on the reverse input terminal of the fourth operational amplifier U3015A through the third resistor R3022 and the first resistor R3017 and is maintained at 1.5V. The voltage at the gate of the IGBT is maintained at +15V. At the same time, during the rising process of the gate voltage of the IGBT, the second diode D3006 will be cut off at a certain moment, so that the first voltage source no longer acts on the gate of the IGBT. In this way, by controlling the different channels of the second selection switch U3016, the voltage source acting on the gate of the IGBT is switched to the first voltage source or the second voltage source.

[0098] In order to accurately sample the saturation voltage drop of the IGBT, the voltage sampling unit of this embodiment includes: a voltage storage circuit, a third selection switch U3022, a voltage holding circuit and a voltage acquisition circuit; the output ends of the voltage acquisition circuit and the voltage storage circuit are respectively connected to the input end of the second ADC unit U3018, the input end of the voltage storage circuit is connected to the output end of the third selection switch U3022, the first channel selection end SA of the third selection switch U3022 is suspended, the second channel selection end SB of the third selection switch U3022 is connected to the output end of the voltage holding circuit, and the input end of the voltage holding circuit is connected to the output end of the voltage acquisition circuit; the voltage acquisition circuit is used to collect the on-voltage value of the IGBT, and the third selection switch U3022 is used to select the output end D of the third selection switch U3022 and the second channel selection end SB of the third selection switch U3022 after receiving the third control signal, so that the voltage holding circuit stores the collected on-voltage value of the IGBT in the form of equivalent electrical energy to the voltage storage circuit.

[0099] like Figure 6a to Figure 6c As shown, the voltage storage circuit includes a second capacitor C3055 and a fifth operational amplifier U3021A, the second capacitor C3055 is connected in series between the output terminal and the reverse input terminal of the fifth operational amplifier U3021A, and the output terminal of the fifth operational amplifier U3021A is connected to the first input terminal IN1 of the second ADC unit U3018, the positive input terminal of the fifth operational amplifier U3021A is grounded, the reverse input terminal of the fifth operational amplifier U3021A is connected to the output terminal D of the third selection switch U3022, and the input terminal IN of the third selection switch U3022 is connected to the second positive output terminal of the third monostable multivibrator U1017.

[0100] The voltage holding circuit includes a sixth operational amplifier U3020A, a seventh operational amplifier U3017A, an eighth resistor R3026 and a ninth resistor R3029; the voltage acquisition circuit includes a tenth resistor R3034 and an eleventh resistor R3035. The first end of the tenth resistor R3034 is connected to the collector c of the IGBT and the reverse input terminal of the seventh operational amplifier U3017A, the second end of the tenth resistor R3034 is connected to the first end of the eleventh resistor R3035 and is connected to the second input terminal IN0 of the second ADC unit U3018, the second end of the eleventh resistor R3035 is connected to the emitter e of the IGBT and the forward input terminal of the seventh operational amplifier U3017A, the output terminal of the seventh operational amplifier U3017A is connected to the second end of the ninth resistor R3029, the first end of the ninth resistor R3029 is connected to the forward input terminal of the sixth operational amplifier U3020A, the reverse input terminal of the sixth operational amplifier U3020A is connected to its output terminal and its output terminal is connected to the second channel selection terminal SB of the third selection switch U3022, and the eighth resistor R3026 is connected in series between the first end of the ninth resistor R3029 and the first end of the second capacitor C3055.

[0101] When the IGBT is controlled to work in the linear region, the voltage between the collector and the emitter of the IGBT is relatively large, and is sampled by voltage division through the eighth resistor R3026 and the ninth resistor R3029, and the collected voltage is transmitted to the MCU via the second input terminal IN0 of the second ADC unit U3018. At the same time, the collected voltage is transmitted to the output terminal of the fifth operational amplifier U3021A via the seventh operational amplifier U3017A, the eighth resistor R3026 and the ninth resistor R3029 and applied to both ends of the second capacitor C3055.

[0102] Since the enable terminal EN of the third selection switch U3022 is grounded, when the third selection switch U3022 does not receive the third control signal, the first channel selection terminal SA of the third selection switch U3022 and the output terminal D of the third selection switch U3022 are selected. When the input terminal IN of the third selection switch U3022 receives the third control signal, the second channel selection terminal SB of the third selection switch U3022 and the output terminal D of the third selection switch U3022 are selected, and the collected voltage is applied to both ends of the second capacitor C3055. In this embodiment, the resistance values ​​of the eighth resistor R3026 and the ninth resistor R3029 are 1:1, so the voltage applied to both ends of the second capacitor C3055 is the voltage between the emitter and the collector of the IGBT. During this period, since the second capacitor C3055 has no discharge circuit, the voltage of the second capacitor C3055 is maintained. Since it has entered saturation conduction for a period of time, the voltage applied across the second capacitor C3055 is the saturation voltage drop between the emitter and collector of the IGBT for MCU to read.

[0103] In summary, this embodiment controls the IGBT to operate in the saturation region to calibrate the corresponding relationship between the saturation voltage drop and the junction temperature of the IGBT, controls the IGBT to operate in the linear region to obtain the power loss of the IGBT, and after obtaining the power loss of the IGBT, switches to collecting the saturation voltage drop of the IGBT under the same conditions as those for calibrating the corresponding relationship between the saturation voltage drop and the junction temperature of the IGBT, thereby calibrating the corresponding relationship between the power loss and the saturation voltage drop of the IGBT, and then converting the corresponding relationship between the power loss and the saturation voltage drop of the IGBT. Therefore, in actual applications, it is only necessary to detect the power loss of the IGBT to obtain the corresponding junction temperature, without adding an additional detection circuit in the control system, thereby reducing the cost of the control system.

[0104] The optional embodiments of the present invention are described in detail above in conjunction with the accompanying drawings. However, the embodiments of the present invention are not limited to the specific details in the above embodiments. Within the technical concept of the embodiments of the present invention, various simple modifications can be made to the technical solutions of the embodiments of the present invention, and these simple modifications all belong to the protection scope of the embodiments of the present invention.

[0105] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. To avoid unnecessary repetition, the embodiments of the present invention will not further describe various possible combinations.

[0106] In addition, various embodiments of the present invention may be arbitrarily combined, and as long as they do not violate the concept of the embodiments of the present invention, they should also be regarded as the contents disclosed in the embodiments of the present invention.

Claims

1. An IGBT junction temperature calibration system, used for calibrating the junction temperature of an IGBT, characterized in that: include: A main control module, a temperature acquisition module, an IGBT driving module, a power sampling module and a current detection control module; the main control module is connected to the temperature acquisition module, the IGBT driving module, the power sampling module and the current detection control module respectively; the IGBT driving module, the power sampling module and the current detection control module are connected to the IGBT respectively; The power sampling module is used to collect a first on-current value and a first on-voltage value between the collector and the emitter of the IGBT when the IGBT operates in a linear region, and to collect a second on-voltage value between the collector and the emitter of the IGBT when the IGBT operates in a saturation region; The temperature acquisition module is used to acquire the temperature value of the IGBT; The main control module is used for: Control the current detection control module to apply a conduction current to the IGBT, control the IGBT driving module to apply a first driving voltage to the IGBT to control the IGBT to operate in a linear region, and control the IGBT driving module to apply a second driving voltage to the IGBT to control the IGBT to operate in a saturation region; as well as The power loss of the IGBT is calculated according to the first on-current value and the first on-voltage value, and the corresponding relationship between the power loss of the IGBT and the temperature value of the IGBT is calibrated according to the second on-voltage value, the temperature value of the IGBT and the power loss of the IGBT.

2. The IGBT junction temperature calibration system according to claim 1, characterized in that: The main control module includes a central processing unit and a core logic control unit; The power sampling module includes a current sampling unit, a voltage sampling unit, a first ADC unit and a second ADC unit; The current detection control module includes a current control unit, a current power unit and a DAC unit; The central processing unit is connected to the core logic control unit, the first ADC unit, the second ADC unit, the DAC unit and the temperature acquisition module respectively; the first ADC unit is connected to the current sampling unit, the second ADC unit is connected to the voltage sampling unit, the DAC unit is connected to the current control unit, the core logic control unit is connected to the IGBT driving module, the current control unit and the voltage sampling unit respectively; the current sampling unit and the current control unit are connected to the current power unit respectively; the current power unit and the voltage sampling unit are connected to the IGBT respectively.

3. The IGBT junction temperature calibration system according to claim 2, characterized in that: The temperature acquisition module includes: a first temperature acquisition submodule, a second temperature acquisition submodule and a third ADC unit; The first temperature acquisition submodule and the second temperature acquisition submodule are respectively connected to the third ADC unit, and the third ADC unit is connected to the central processing unit; The first temperature acquisition submodule is used to acquire the temperature value of the temperature acquisition thermocouple arranged on the IGBT as the temperature value of the IGBT, and the second temperature acquisition submodule is used to acquire the temperature value of the thermistor inside the IGBT as the temperature value of the IGBT; The first temperature acquisition submodule includes: a temperature sensor, a first amplification unit and a first digital isolation unit; The output end of the temperature sensor is connected to the input end of the first amplifying unit, the output end of the first amplifying unit is connected to the input end of the third ADC unit, the output end of the third ADC unit is connected to the input end of the first digital isolation unit, and the output end of the first digital isolation unit is connected to the input end of the central processing unit; The temperature sensor is used to collect the temperature value of the temperature collection thermocouple; The second temperature acquisition submodule includes: a second amplification unit and a second digital isolation unit; The input end of the second amplifying unit is connected to the thermistor to collect the voltage value of the thermistor, the output end of the second amplifying unit is connected to the input end of the third ADC unit, the output end of the third ADC unit is connected to the input end of the second digital isolation unit, and the output end of the second digital isolation unit is connected to the input end of the central processing unit.

4. The IGBT junction temperature calibration system according to claim 2, characterized in that: The core logic control unit includes a trigger circuit, and the trigger circuit includes: A first delay trigger circuit, a second delay trigger circuit and a third delay trigger circuit; The input end of the first delay trigger circuit is connected to the output end of the central processing unit, and the output end of the first delay trigger circuit is connected to the input end of the second delay trigger circuit and the input end of the current control unit; The output end of the second delay trigger circuit is connected to the input end of the third delay trigger circuit and the input end of the IGBT driving module; The output end of the third delay trigger circuit is connected to the input end of the voltage sampling unit; The output end of the central processing unit outputs a fixed-frequency PWM control signal to trigger the first delay trigger circuit to generate a first control signal, trigger the second delay trigger circuit to generate a second control signal, and trigger the third delay trigger circuit to generate a third control signal, so as to control the current control unit to apply a conduction current to the IGBT, control the IGBT drive module to apply the second drive voltage to the IGBT, and control the voltage sampling unit to collect the second conduction voltage value according to a set timing.

5. The IGBT junction temperature calibration system according to claim 4, characterized in that: The first delay trigger circuit includes a first monostable multivibrator, the second delay trigger circuit includes a second monostable multivibrator, and the third delay trigger circuit includes a third monostable multivibrator; The first falling edge trigger end of the first monostable multivibrator is connected to the output end of the central processing unit, the first forward output end of the first monostable multivibrator is connected to the input end of the current control unit and the first rising edge trigger end of the second monostable multivibrator, the first forward output end of the second monostable multivibrator is connected to the second falling edge trigger end of the second monostable multivibrator, the second forward output end of the second monostable multivibrator is connected to the input end of the IGBT driving module and the first rising edge trigger end of the third monostable multivibrator, the first forward output end of the third monostable multivibrator is connected to the second falling edge trigger end of the third monostable multivibrator, and the second forward output end of the third monostable multivibrator is connected to the input end of the voltage sampling unit.

6. The IGBT junction temperature calibration system according to claim 4, characterized in that: The current power unit comprises a current sampling resistor and a power MOS tube, and the current sampling resistor and the power MOS tube are connected in series on a bus; The current control unit comprises: A first selection switch, a voltage follower circuit and a push-pull circuit, wherein the output end of the DAC unit is connected to the channel selection end of the first selection switch, the input end of the first selection switch is connected to the output end of the first delay trigger circuit, the output end of the first selection switch is connected to the input end of the voltage follower circuit, the output end of the voltage follower circuit is connected to the input end of the push-pull circuit, and the output end of the push-pull circuit is connected to the gate of the power MOS tube; The first selection switch is used to select the channel selection end of the first selection switch and the output end of the first selection switch after receiving the first control signal, the voltage follower circuit is used to input the voltage output by the output end of the DAC unit into the push-pull circuit, and the push-pull circuit is used to apply the input voltage to the gate of the power MOS tube after voltage regulation to generate a constant current flowing through the bus, and apply the generated constant current between the emitter and collector of the IGBT through the bus.

7. The IGBT junction temperature calibration system according to claim 6, characterized in that: The current control unit also includes a voltage feedback circuit; The input end of the voltage feedback circuit is connected to the two ends of the current sampling resistor, and the output end of the voltage feedback circuit is connected to the input end of the voltage follower circuit. The voltage feedback circuit is used to feed back the voltage across the current sampling resistor to the voltage follower circuit so that the voltage follower circuit adjusts the output of the voltage follower circuit according to the voltage fed back by the voltage feedback circuit until a stable state is reached.

8. The IGBT junction temperature calibration system according to claim 4, characterized in that: The IGBT driving module comprises: A second selection switch and a voltage switching circuit; The input end of the second gate switch is connected to the output end of the second delay trigger circuit, the first channel selection end of the second gate switch is grounded, the second channel selection end of the second gate switch is in contact with the voltage, the output end of the second gate switch is connected to the voltage switching circuit, and the gate of the IGBT is connected to the first voltage source and the second voltage source through the voltage switching circuit; The second gating switch is used to gating the first channel selection end of the second gating switch and the output end of the second gating switch before receiving the second control signal, and gating the second channel selection end of the second gating switch and the output end of the second gating switch after receiving the second control signal; The voltage switching circuit is used for switching the first voltage source to apply the first driving voltage to the gate of the IGBT after the first channel selection terminal of the second selection switch and the output terminal of the second selection switch are selected, and for triggering the voltage switching circuit to switch the second voltage source to apply the second driving voltage to the gate of the IGBT after the second channel selection terminal of the second selection switch and the output terminal of the second selection switch are selected.

9. The IGBT junction temperature calibration system according to claim 8, characterized in that: The voltage switching circuit comprises: an amplifying subcircuit and a switching subcircuit; The input end of the amplifier subcircuit is connected to the output end of the second gate switch, the output end of the amplifier subcircuit is connected to the control end of the switch subcircuit, the gate of the IGBT is connected to the second voltage source through the switch subcircuit, and the gate of the IGBT is connected to the first voltage source through the switch subcircuit; The amplifying sub-circuit is used for controlling the switching sub-circuit to switch the first voltage source to apply the first driving voltage to the gate of the IGBT after the first channel selection terminal of the second gating switch and the output terminal of the second gating switch are gated; and After the second channel selection terminal of the second gate switch and the output terminal of the second gate switch are gated, the trigger voltage is amplified to control the switch subcircuit to switch the second voltage source to apply the second driving voltage to the gate of the IGBT.

10. The IGBT junction temperature calibration system according to claim 4, characterized in that: The voltage sampling unit includes: a voltage storage circuit, a third selection switch, a voltage holding circuit and a voltage acquisition circuit; The output ends of the voltage acquisition circuit and the voltage storage circuit are respectively connected to the input end of the second ADC unit, the input end of the voltage storage circuit is connected to the output end of the third gating switch, the first channel selection end of the third gating switch is suspended, the second channel selection end of the third gating switch is connected to the output end of the voltage holding circuit, and the input end of the voltage holding circuit is connected to the output end of the voltage acquisition circuit; The voltage acquisition circuit is used to acquire the on-voltage value of the IGBT, and the third selection switch is used to select the output end of the third selection switch and the second channel selection end of the third selection switch after receiving the third control signal, so that the voltage holding circuit can store the collected on-voltage value of the IGBT in the form of equivalent electrical energy to the voltage storage circuit.

Images