CN215415729U

CN215415729U - IGBT drive circuit

Info

Publication number: CN215415729U
Application number: CN202120635353.4U
Authority: CN
Inventors: 史胜利; 杜松贺; 王振达; 王伟
Original assignee: Baoding R&D Branch of Honeycomb Transmission System Jiangsu Co Ltd; Honeycomb Drive System Jiangsu Co Ltd
Current assignee: Baoding R&D Branch of Honeycomb Transmission System Jiangsu Co Ltd; Honeycomb Drive System Jiangsu Co Ltd
Priority date: 2020-10-29
Filing date: 2020-10-29
Publication date: 2022-01-04
Anticipated expiration: 2030-10-29
Also published as: CN213813851U

Abstract

The embodiment of the utility model provides an IGBT driving circuit, and relates to the technical field of IGBT driving control. The IGBT drive circuit includes: a gate switch and a voltage switching circuit; the input end of the gating switch is used for receiving an enabling control signal, the output end of the gating switch is connected with the input end of the voltage switching circuit, the first channel selection end of the gating switch is grounded, the second channel selection end of the gating switch is connected with a reference voltage source, and the gate pole of the IGBT is connected with the first voltage source and the second voltage source through the voltage switching circuit. The utility model can control and switch the voltage applied to the IGBT gate pole through the enable control signal, realizes the isolation driving of the IGBT through the discrete device, has stable system and more flexible driving mode, and has wider power range and larger driving capability compared with an integrated circuit.

Description

IGBT drive circuit

The application is a divisional application of a utility model patent with the application number of 202022456469.X and the application date of 2020.10.29, named as an IGBT junction temperature calibration system.

Technical Field

The utility model relates to the technical field of IGBT drive control, in particular to an IGBT drive circuit.

Background

In power electronics applications, IGBTs operate primarily in a switching state and periodically experience various static and dynamic conditions that cause energy losses, resulting in heating of the power loss device and causing IGBT junction temperature fluctuations. Because of the material and the package of the IGBT chip, the junction temperature of the IGBT chip is not allowed to exceed the maximum allowable range, and in practical application, the junction temperature of the IGBT chip needs to be accurately obtained to ensure that the controller works normally.

The existing junction temperature detection method mainly comprises a temperature-sensitive parameter method, and the temperature-sensitive parameter method is used for knowing that when an IGBT conducts a small current Im equal to 100mA, a good linear relation exists between saturation voltage drop and junction temperature, but the current of the IGBT chip in actual work is far more than 100mA, so that the measurement of the junction temperature of the IGBT through the saturation voltage drop in the actual work has certain difficulty. At present, a relatively perfect IGBT junction temperature test calibration system does not exist, IGBT driving circuits matched with the system are rare, the cost of using an integrated driving chip is higher than that of a discrete device, functions of partial chips are not needed, function waste is caused, and better matching requirements are difficult.

SUMMERY OF THE UTILITY MODEL

The embodiment of the utility model aims to provide an IGBT driving circuit, so as to solve the problem that the IGBT driving circuit for an IGBT junction temperature test calibration system is not complete at present.

In order to achieve the above object, the present invention provides an IGBT driving circuit including:

a gate switch U3016 and a voltage switching circuit;

the input end of the gating switch U3016 is used for receiving an enable control signal, the output end of the gating switch U3016 is connected with the input end of the voltage switching circuit, the first channel selection end of the gating switch U3016 is grounded, the second channel selection end of the gating switch U3016 is connected with a reference voltage source, and the gate pole of the IGBT is connected with the first voltage source and the second voltage source through the voltage switching circuit;

the gating switch U3016 is configured to gate a first channel selection terminal of the gating switch U3016 and an output terminal of the gating switch U3016 before receiving the enable control signal, and gate a second channel selection terminal of the gating switch U3016 and an output terminal of the gating switch U3016 after receiving the enable control signal;

the voltage switching circuit is used for controlling the first voltage source to apply a first driving voltage to the gate of the IGBT after the first channel selection end of the gating switch U3016 and the output end of the gating switch U3016 are gated, and switching the second voltage source to apply a second driving voltage to the gate of the IGBT after the second channel selection end of the gating switch U3016 and the output end of the gating switch U3016 are gated.

Optionally, the IGBT driving circuit further includes:

the output end of the digital isolator U3011 is connected with the input end of the gating switch U3016;

the digital isolator U3011 is configured to receive the enable control signal and send the enable control signal to the gating switch U3016.

Optionally, the voltage switching circuit comprises:

an amplifying sub-circuit and a switching sub-circuit;

the input end of the amplifying sub-circuit is connected with the output end of the gating switch U3016, the output end of the amplifying sub-circuit is connected with the control end of the switching sub-circuit, and the gate pole of the IGBT is respectively connected with the first voltage source and the second voltage source through the switching sub-circuit.

Optionally, the amplifying sub-circuit includes an operational amplifier U3015A and a diode D3005, a forward input terminal of the operational amplifier U3015A is connected to an output terminal of the gating switch U3016, an anode of the diode D3005 is connected to an inverting input terminal of the operational amplifier U3015A, and a cathode of the diode D3005 is connected to an output terminal of the operational amplifier U3015A.

Optionally, the switch sub-circuit comprises:

the circuit comprises a triode Q3000, a triode Q3001, a resistor R3024 and a resistor R3025, wherein the triode Q3000 is an NPN triode, and the triode Q3001 is a PNP triode;

the base of the triode Q3000 is connected with the output end of the operational amplifier U3015A, the collector of the triode Q3000 is connected with the base of the triode Q3001 and the second end of the resistor R3024 in parallel, and the first end of the resistor R3024 and the collector of the triode Q3001 are connected with the second voltage source;

the emitter of the triode Q3000 is connected with the first end of the resistor R3025, the second end of the resistor R3025 is grounded, and the collector of the triode Q3001 is connected with the gate of the IGBT.

Optionally, the amplifying sub-circuit further comprises:

a resistor R3017, a resistor R3022 and a capacitor C3057;

a first end of the resistor R3017 is connected with an inverting input end of the operational amplifier U3015A, and a second end of the resistor R3017 is grounded;

a first end of the resistor R3022 is connected to the inverting input terminal of the operational amplifier U3015A, and a second end of the resistor R3022 is connected to the collector of the transistor Q3001;

the capacitor C3057 is connected in parallel with the resistor R3022.

Optionally, the switch sub-circuit further comprises:

a diode D3006, a resistor R3027, and a resistor R3028;

the anode of the diode D3006 is connected to the collector of the IGBT, the cathode of the diode D3006 is connected to the first end of the resistor R3027, the second end of the resistor R3027 is connected to the first end of the resistor R3028 and connected to the gate of the IGBT, and the second end of the resistor R3028 is grounded.

Optionally, the switch sub-circuit further comprises:

and a cathode of the diode D3007 is connected to the second end of the resistor R3027 and the first end of the resistor R3028, and is connected to the gate of the IGBT, and an anode of the diode D3007 is grounded.

According to the technical scheme, the voltage applied to the IGBT gate pole can be controlled and switched through the enabling control signal, the switching of the working state of the IGBT between the linear region or the saturation region can be effectively controlled, the automatic control of the whole process of IGBT junction temperature calibration test and the measurement of the IGBT junction temperature calibration are facilitated, the test result is more accurate, and the test efficiency is higher. Meanwhile, the isolated driving of the IGBT is realized through discrete devices, the system is stable, the driving mode is more flexible, and compared with an integrated circuit, the power range is wider and the driving capability is larger.

Additional features and advantages of embodiments of the utility model will be set forth in the detailed description which follows.

Drawings

The accompanying drawings, which are included to provide a further understanding of the embodiments of the utility model and are incorporated in and constitute a part of this specification, illustrate embodiments of the utility model and together with the description serve to explain the embodiments of the utility model without limiting the embodiments of the utility model. In the drawings:

fig. 1 is a schematic structural diagram of a system of an IGBT junction temperature calibration system according to a preferred embodiment of the present invention;

FIG. 2 is a schematic structural diagram of a temperature acquisition module provided in the preferred embodiment of the present invention;

FIGS. 3 a-3 c are circuit diagrams of a core logic control unit according to a preferred embodiment of the present invention;

fig. 4a to 4c are circuit diagrams of a current control unit according to a preferred embodiment of the present invention;

fig. 5a to 5c are circuit diagrams of an IGBT driving circuit according to a preferred embodiment of the present invention;

fig. 6a to 6c are circuit diagrams of a voltage sampling unit according to a preferred embodiment of the present invention.

Detailed Description

The following detailed description of embodiments of the utility model refers to the accompanying drawings. It should be understood that the detailed description and specific examples, while indicating the present invention, are given by way of illustration and explanation only, not limitation.

As shown in fig. 1, the present embodiment provides an IGBT driving circuit, which is applied to an IGBT junction temperature calibration system for performing junction temperature calibration on an IGBT, where the IGBT junction temperature calibration system includes:

the device comprises a main control module, a temperature acquisition module, an IGBT (insulated gate bipolar transistor) driving module, a power sampling module and a current detection control module; the main control module is respectively connected with the temperature acquisition module, the IGBT driving module, the power sampling module and the current detection control module; the IGBT driving module, the power sampling module and the current detection control module are respectively connected with the IGBT;

the power sampling module is used for collecting a first conduction current value when the IGBT works in a linear region and a first conduction voltage value between a collector electrode and an emitter electrode of the IGBT, and collecting a second conduction voltage value between the collector electrode and the emitter electrode of the IGBT when the IGBT works in a saturation region;

the temperature acquisition module is used for acquiring the temperature value of the IGBT;

the main control module is used for:

the control current detection control module is used for applying conduction current to the IGBT, controlling the IGBT driving module to apply first driving voltage to the IGBT to control the IGBT to work in a linear region, and controlling the IGBT driving module to apply second driving voltage to the IGBT to control the IGBT to work in a saturation region; and

and calculating the power loss of the IGBT according to the first conduction current value and the first conduction voltage value, and calibrating the corresponding relation between the power loss of the IGBT and the temperature value of the IGBT according to the second conduction voltage value, the temperature value of the IGBT and the power loss of the IGBT.

The junction temperature calibration system provided by the embodiment can switch between a linear region or a saturation region by controlling the working state of the IGBT, and collect different junction temperature calibration parameters when controlling the IGBT to work in different working states, so that the full-process automatic control of the junction temperature calibration test of the IGBT is realized, the measurement of the junction temperature calibration of the IGBT is facilitated to be standardized, the test result is more accurate, and the test efficiency is higher.

Specifically, main control module communicates with IGBT drive module, power sampling module and temperature acquisition module through SPI communication module, and simultaneously, main control module still carries out data interaction through UART module and host computer communication connection in order to carry out with the host computer. The main control module, the temperature acquisition module, the IGBT driving module, the power sampling module and the current detection control module can be integrated on the same circuit board or can be arranged independently. The IGBT driving module receives the control of the main control module to switch the driving voltage applied to the gate pole of the IGBT so as to control the IGBT to work in a linear region or a saturation region, when the IGBT driving module does not control the gate pole voltage of the IGBT, the IGBT works in the linear region, when the IGBT driving module switches to apply 15V voltage to the gate pole of the IGBT, the IGBT works in the saturation region, so that the junction temperature calibration parameters of the IGBT in different working states, such as saturation voltage drop, IGBT temperature and the like, can be acquired by controlling the IGBT to work in different working regions, and further the main control module can perform automatic junction temperature calibration on the IGBT according to the acquired junction temperature calibration parameters. In order to further solve the problem that the junction temperature of the IGBT is measured through saturation voltage drop in the actual work of the prior IGBT junction temperature calibration, so that the junction temperature calibration of the IGBT is inaccurate, the power loss of the IGBT is calculated by controlling the IGBT to work in a linear zone, and switching the IGBT to work in a saturation region after the power loss of the IGBT is obtained, collecting the temperature value and the conduction voltage value of the IGBT, further, the relation between the power loss and the temperature of the IGBT can be calibrated by calibrating the relation between the power loss and the saturation voltage drop of the IGBT and calibrating the relation between the saturation voltage drop and the temperature of the IGBT, therefore, in practical application, the corresponding junction temperature can be obtained only by detecting the power loss of the IGBT without additionally adding a detection circuit in a control system, the cost of the control system is reduced, meanwhile, the problem that junction temperature calibration accuracy is low due to the fact that IGBT saturation voltage drop cannot be accurately obtained in practical application is effectively solved.

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

the central processing unit is respectively connected with 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 with the current sampling unit, the second ADC unit is connected with the voltage sampling unit, the DAC unit is connected with the current control unit, the core logic control unit is respectively connected with the IGBT driving module, the current control unit and the voltage sampling unit, the current sampling unit and the current control unit are respectively connected with the current power unit, and the current power unit and the voltage sampling unit are respectively connected with the IGBT. The central processing unit is an MCU, and the MCU with the model number of PIC32MZ1024EFE064-IPT is adopted as the central processing unit of the system in the embodiment.

In this embodiment, a complete working process of the junction temperature calibration system includes: in the first stage, a junction temperature calibration system runs in a steady state under high power; and in the second stage, switching the current and the voltage, and sampling the saturated conduction voltage drop of the IGBT.

The first stage is as follows: the MCU controls the IGBT driving module to switch the bus voltage through the core logic control unit to provide a first driving voltage for a gate pole of the IGBT so as to enable the IGBT to work in a linear region; the MCU is in SPI communication with the current control unit through the DAC unit so as to control the current output by the current power unit, and meanwhile, 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 so as to control the current equalization of the output current; the MCU acquires a first conduction current value flowing between the emitter and the collector of the IGBT through the current sampling unit and acquires a first conduction voltage value between the emitter and the collector of the IGBT through the voltage sampling unit, and the current power loss of the IGBT can be calculated through the first conduction current value and the first conduction voltage value.

And a second stage: the MCU provides a PWM control signal with fixed frequency and duty ratio for the core logic control unit, and the frequency of the PWM control signal in the embodiment is 10 Hz; at each rising edge of the PWM control signal, the core logic control unit firstly triggers the control current control unit to regulate the output current to 100mA, so that 100mA conduction current is applied to the IGBT; after a preset small time delay, the core logic control unit triggers and controls the IGBT driving module to switch the driving voltage applied to the gate pole of the IGBT into a second driving voltage of +15V, so that the IGBT is in a saturated conduction state; after a preset small delay, the core logic control unit triggers and controls the voltage sampling unit to sample the voltage of the IGBT to obtain a second breakover voltage value of the IGBT, namely the saturation voltage drop of the IGBT, and then the second breakover voltage value is transmitted to the MCU through the second ADC unit through SPI communication, so that the saturation voltage drop under the current power loss of the IGBT can be obtained, meanwhile, the MCU acquires 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, and therefore the junction temperature corresponding to the current power loss of the IGBT is obtained.

The power loss, the saturation voltage drop and the junction temperature of the IGBT under different environmental temperatures are acquired and calculated through the control process, and the automatic calibration of the corresponding relation between the power loss and the junction temperature of the IGBT can be realized.

In this embodiment, the temperature collection of the IGBT includes collecting the temperature of the IGBT by a thermocouple disposed on an IGBT substrate and collecting the voltage value of an NTC thermistor integrated inside the IGBT to collect the temperature of the IGBT, and therefore, the temperature collection module includes:

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 with a third ADC unit, and the third ADC unit is connected with the central processing unit; the first temperature acquisition submodule is used for acquiring a temperature value of a temperature acquisition thermocouple arranged on the IGBT as a temperature value of the IGBT, and the second temperature acquisition submodule is used for acquiring a temperature value of a thermistor inside the IGBT as a temperature value of the IGBT.

As shown in fig. 2, the first temperature acquisition submodule includes: the temperature sensor, the first amplifying unit and the first digital isolation unit; the output end of the temperature sensor is connected with the input end of the first amplification unit, the output end of the first amplification unit is connected with the input end of the third ADC unit, the output end of the third ADC unit is connected with the input end of the first digital isolation unit, and the output end and the input end of the first digital isolation unit are in communication connection through the SPI; the temperature sensor is used for collecting temperature values of the temperature collection thermocouples, and the temperature sensor collects electric signals of the temperature collection thermocouples at the corresponding temperatures through the connectors.

The second temperature acquisition submodule comprises: a second amplifying unit and a second digital isolation unit; the input of second amplifying unit passes through the connector and is connected the voltage value in order to gather thermistor with thermistor, and simultaneously, supply power for thermistor sampling through high accuracy reference power supply, the output of second amplifying unit is connected with the input of third ADC unit, the output of third ADC unit is connected with the input of second digital isolation unit, the output of second digital isolation unit passes through SPI communication connection with MCU's input, the analog quantity that represents the temperature value of temperature collection thermocouple and the analog quantity that represents thermistor's temperature value that third ADC unit will gather are sent for MCU through SPI communication after being converted into the digital quantity.

The first amplification unit and the second amplification unit are operational amplifiers with the model number being 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 ADuM225N0 BRIZ. The first digital isolation unit and the second digital isolation unit are used for isolating the MCU side from the temperature acquisition side so as to protect the MCU. Therefore, the junction temperature calibration system of the embodiment can realize the temperature acquisition of the IGBT by the temperature acquisition thermocouple or the NTC thermistor inside the IGBT, and can accurately acquire the temperature of different types of IGBTs.

Wherein, the core logic control unit includes trigger circuit, and trigger circuit includes:

the circuit comprises 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 with the output end of the central processing unit, and the output end of the first delay trigger circuit is connected with 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 with 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 with the input end of the voltage sampling unit;

the output end of the central processing unit outputs a PWM control signal Trigger source with fixed frequency to Trigger the first time delay Trigger circuit to generate a first control signal cur source ctr, Trigger the second time delay Trigger circuit to generate a second control signal gate driver and Trigger the third time delay Trigger circuit to generate a third control signal vce sample ctr, so as to control the current control unit to apply a conducting 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 a second conducting voltage value according to a set time sequence, further when the rising edge of the PWM control signal is generated, the first time delay Trigger circuit generates a first control signal to Trigger the control current control unit to adjust the output current to 100mA, after the preset time delay, the first time delay Trigger circuit triggers the second time delay Trigger circuit to generate a second control signal to Trigger the IGBT driving module to switch the driving voltage applied to the gate of the IGBT into a second driving voltage of +15V, and after a preset time delay, the second time delay trigger circuit triggers the third time delay trigger circuit to generate a third control signal so as to trigger the control voltage sampling unit to sample the voltage of the IGBT.

As shown in fig. 3a to 3c, in the present embodiment, the core logic control unit further includes:

a first switch JP1000, a second switch JP1001, and a control signal generating circuit; the output end of the central processing unit is connected with the input end of the first delay trigger circuit through a first switch JP1000, and the output end of the control signal generating circuit is connected with the input end of the first delay trigger circuit through a second switch JP 1001; the output end of the control signal generating circuit outputs a PWM control signal with the same fixed frequency as that output by the central processing unit so as 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 that the current control unit is controlled to apply a conduction current to the IGBT, the IGBT driving module is controlled to apply a second driving voltage to the IGBT and the voltage sampling unit is controlled to collect a second conduction voltage value according to a set time sequence; the first switch JP1000 and the second switch JP1001 operate asynchronously, and further in practical application, whether the PWM control signal is output by the MCU or the control signal generating circuit can be switched by the first switch JP1000 and the second switch JP 1001. The control signal generating circuit is composed of a one-way Schmitt trigger U1002, peripheral resistors AR1000 and R1000, and capacitors C1000 and C1001.

The first delay trigger circuit comprises a first monostable multivibrator U1006, the second delay trigger circuit comprises a second monostable multivibrator U1009, and the third delay trigger circuit comprises a third monostable multivibrator U1017; first falling edge trigger terminal 1 of first monostable multivibrator U1006

The first switch JP1000 is connected to the output of the central processing unit, the first forward output terminal 1Q of the first monostable multivibrator U1006 is connected to the input of the current control unit and the first rising edge trigger terminal 1B of the second monostable multivibrator U1009, the first forward output terminal 1Q of the second monostable multivibrator U1009 is connected to the second falling edge trigger terminal 2 of the second monostable multivibrator U1009

Connected, second monostable stateA second forward output end of the multivibrator U1009 is connected with an input end of the IGBT driving module and a first rising edge trigger end 1B of the third monostable multivibrator U1017, and a first forward output end 1Q of the third monostable multivibrator U1017 and a second falling edge trigger end of the third monostable multivibrator U1017

And the second positive output end of the third monostable multivibrator U1017 is connected with the input end of the voltage sampling unit. The first monostable multivibrator U1006, the second monostable multivibrator U1009 and the third monostable multivibrator U1017 adopt monostable multivibrators with the model number SN74LV123ATPWRQ1, the delay working time is adjusted through the proportion of external capacitors and resistors of the monostable multivibrators, and a specific circuit for delay control is a typical application of the SN74LV123ATPWRQ1, which is not described herein again.

When power loss calculation and saturation voltage drop acquisition are performed on the IGBT, the current control unit is required to control the current output by the IGBT to be a constant current, and therefore, the current power unit includes a current sampling resistor and a power MOS transistor, which are connected in series to a bus, as shown in fig. 4a to 4c, the current control unit includes:

the output end of the DAC unit U2004 is connected with a channel selection end of the first gating switch U2007, an input end IN of the first gating switch U2007 is connected with an output end of the first delay trigger circuit, namely a first positive output end 1Q of the first monostable multivibrator U1006, an output end D of the first gating switch U2007 is connected with an input end of the voltage follower circuit, an output end of the voltage follower circuit is connected with an input end of the push-pull circuit, and an output end of the push-pull circuit is connected with a gate pole of the power MOS tube through a plug connector CN 2001; the first gating switch U2007 is configured to gate a channel selection end of the first gating switch U2007 and an output end of the first gating switch U2007 after receiving the first control signal, the voltage follower circuit is configured to input a voltage output by the output end of the DAC unit U2004 into the push-pull circuit, and the push-pull circuit is configured to apply the voltage regulated input voltage to a gate of the power MOS transistor, so as to generate a constant current flowing through the bus through the current sampling resistor, so that the power MOS transistor, the current sampling resistor, and the current control unit form a constant current source with an optional output, and the output constant current is applied between an emitter and a collector of the IGBT through the bus.

In order to ensure that the currents output by the current control unit and the current power unit are constant, the current control unit further comprises a voltage feedback circuit, the input end of the voltage feedback circuit is connected with the two ends of the current sampling resistor, the output end of the voltage feedback circuit is connected with the input end of the voltage follower circuit, and the voltage feedback circuit is used for feeding the voltages at the two ends of the current sampling resistor back to the voltage follower circuit so that the voltage follower circuit adjusts the output of the voltage follower circuit until the voltage follower circuit reaches a stable state according to the voltage fed back by the voltage feedback circuit.

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 gate 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 gate 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 the current control unit outputs a large current after the first gate switch U2007 gates the first channel selection terminal SA thereof, and outputs a small current of 100mA after the first gate switch U2007 gates the second channel selection terminal SB thereof.

The voltage follower circuit comprises a first operational amplifier U2011A and a second operational amplifier U2013A, the voltage feedback circuit comprises a third operational amplifier U2018A, wherein the first operational amplifier U2011A, the second operational amplifier U2013A and corresponding peripheral circuits form the voltage follower circuit, the specific structure of the voltage follower circuit of the embodiment can be realized by adopting the existing voltage follower circuit structure, and the details are not repeated here. An output end D of the first gating switch U2007 is connected with a forward input end of a first operational amplifier U2011A, a reverse input end of the first operational amplifier U2011A is connected with an output end of the first operational amplifier U2011 and is connected with a forward input end of a second operational amplifier U2013A through a resistor R2005, an output end of the second operational amplifier U2013A is connected with a reverse input end of the second operational amplifier U2013A through a peripheral circuit and is connected with an output end of a third operational amplifier U2018A, an output end of the third operational amplifier U2018A is connected with a reverse output end of a third operational amplifier U2018A through the peripheral circuit and is connected with a first end of a current sampling resistor through a plug connector CN2001, and a forward input end of the third operational amplifier U2018A is connected with a second end of the current sampling resistor through the plug connector CN 2001.

When the input terminal of the first gating switch U2007 is at a low level, the first channel selection terminal SA and the output terminal D are gated, and when the input terminal of the first gating switch U2007 is at a high level, the second channel selection terminal SB and the output terminal D are gated. In this embodiment, when the IGBT is controlled to operate in the linear region, the first gate switch U2007 gates the first channel selection terminal SA and the output terminal D, and when the IGBT is controlled to operate in the saturation region, that is, after the input terminal of the first gate switch U2007 receives the first control signal, the input terminal of the first gate switch U2007 is at a high level, and at this time, the input terminal of the first gate switch U2007 gates the second channel selection terminal SB and the output terminal D, so that the first gate switch U2007 can select the output voltage corresponding to the current outputted by the current control unit through the current power unit as a large current or a sampling current of 100mA, the voltage outputted by the DAC unit U2004 is inputted to the push-pull circuit through the first operational amplifier U2011A and the second operational amplifier U2013A, and the voltage is adjusted by the push-pull circuit and then applied to the gate of the power MOS transistor, the current flowing through the power MOS transistor is increased, and the current flowing through the current sampling resistor is increased, and the voltage increase at both ends of the current sampling resistor causes the forward input terminal and the reverse input terminal of the third operational amplifier U2018A The voltage of the end is increased, so that the voltage of the output end of the third operational amplifier U2018A is increased, the voltage of the reverse input end of the second operational amplifier U2013A is further increased, according to the virtual short principle, the forward input end and the reverse input end of the second operational amplifier U2013A form equipotential, and then a constant current source circuit formed by a DAC unit, a current control unit and a current power unit forms a stable state, the circuit works in a stable state, and constant current is output.

The IGBT driving module includes an IGBT driving circuit for switching a driving voltage applied to a gate of the IGBT, as shown in fig. 5a to 5c, the IGBT driving circuit includes: a second gate switch U3016 and a voltage switching circuit; an input end IN of the second gating switch U3016 is connected with an output end of the second delay trigger circuit through the digital isolator U3011, a first channel selection end SA of the second gating switch U3016 is grounded, a second channel selection end SB of the second gating switch U3016 is connected with a reference voltage source UH _ REF, and the reference voltage source UH _ REF outputs a reference voltage as a trigger voltage; the output end D of the second gating switch U3016 is connected with the voltage switching circuit, and the gate pole of the IGBT is connected with the first voltage source and the second voltage source through the voltage switching circuit; the second gating switch U3016 is configured to gate the first channel selection terminal SA of the second gating switch U3016 and the output terminal of the second gating switch U3016 before receiving the second control signal, and gate the second channel selection terminal SB of the second gating switch U3016 and the output terminal of the second gating switch U3016 after receiving the second control signal; the voltage switching circuit is used for switching a first voltage source to apply a first driving voltage to a gate electrode of the IGBT after a first channel selection end SA of the second gating switch U3016 and an output end D of the second gating switch U3016 are gated, and switching a second voltage source to apply a second driving voltage to the gate electrode of the IGBT through the trigger voltage control voltage switching circuit after a second channel selection end SB of the second gating switch U3016 and the output end D of the second gating switch U3016 are gated.

Wherein, the voltage switching circuit includes: an amplifying sub-circuit and a switching sub-circuit; the amplifying sub-circuit comprises a fourth operational amplifier U3015A and a first diode D3005, and the switching sub-circuit comprises 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 triode Q3000, and a second triode Q3001, wherein the first triode Q3000 is an NPN-type triode, and the second triode Q3001 is a PNP-type triode.

An output end D of the second gating switch U3016 is connected to a positive input end of a fourth operational amplifier U3015A, an output end D of the fourth operational amplifier U3015A is connected to a first end of a second resistor R3021, a second end of the second resistor R3021 is connected to a base of a first triode Q3000, a collector of the first triode Q3000 is connected to a base of the second triode Q3001 and connected to a second end of a fourth resistor R3024, a first end of the fourth resistor R3024 is connected to a second voltage source 30P, a first end of the fifth resistor R3025 is connected to an emitter of the first triode Q3000, and a second end of the fifth resistor R3025 is grounded; an emitter of the second triode Q3001 is connected with a second voltage source 30P, a second end of a first capacitor C3057 is connected with a second end of a third resistor R3022 and is connected with a collector of the second triode Q3001 in parallel, a first end of the first capacitor C3057 is connected with a first end of the third resistor R3022 and is connected with a positive electrode of a first diode D3005, a positive electrode of the first diode D3005 is connected with a negative input end of a fourth operational amplifier U3015A, a negative electrode of the first diode D3005 is connected with an output end of the fourth operational amplifier U3015A and is connected with a first end of the second resistor R3021 in parallel, and a negative input end of the fourth operational amplifier U3015A is connected with the first resistor R3017 and is grounded; the collector of the second triode Q3001 is connected with the second end of the sixth resistor R3027 and the first end of the seventh resistor R3028 and is connected with the gate of the IGBT in parallel, the first end of the sixth resistor R3027 is connected with the negative electrode of the second diode D3006, the positive electrode of the second diode D3006 is connected with the collector of the IGBT, the second end of the seventh resistor R3028 is grounded, and the collector and the emitter of the IGBT are connected with 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.

When the IGBT operates in the linear region, the first channel selection terminal SA of the second gate switch U3016 and the output terminal D thereof are gated, at this time, the gate voltage of the IGBT is controlled by the first voltage source, the bus voltage, which is the voltage output by the first voltage source, is divided by the second diode D3006, the sixth resistor R3027 and the seventh resistor R3028 to provide the first driving voltage for the gate of the IGBT, so that the IGBT operates in the linear region, and at the same time, the gate voltage of the IGBT acts on the inverting input terminal of the fourth operational amplifier U3015A through the third resistor R3022, the first capacitor C3057 and the first resistor R3017, and since the first channel selection terminal SA of the second gate switch U3016 is grounded, the output of the fourth operational amplifier U3015A is low, in this embodiment, the output of the fourth operational amplifier U3015A is maintained at-0.7V due to the action of the first diode D3005, so that the first transistor Q3001 and the second transistor Q3001 are turned off 3000, the gate voltage of the IGBT is controlled by the first voltage source, and meanwhile, the circuit output can be effectively ensured to be rapidly switched to a stable state after the driving voltage applied to the gate of the IGBT is switched, and the loop response time is shortened.

When the input terminal IN of the second gating switch U3016 receives the second control signal, the second channel selection terminal SB of the second gating switch U3016 and the output terminal D thereof are gated, the forward input terminal of the fourth operational amplifier U3015A is connected to the reference voltage source UH _ REF, the reference voltage source UH _ REF applies a fixed voltage of 1.5V to the forward input terminal of the fourth operational amplifier U3015A, at this time, the forward input terminal voltage of the fourth operational amplifier U3015A is greater than the reverse input terminal voltage, the output terminal of the fourth operational amplifier U3015 30184 outputs a high level to turn on the first triode Q3000, at this time, the base of the second triode Q3001 is a low level, the second triode Q3001 is connected, the gate of the IGBT is connected to the second voltage source 30P, and the second voltage source 30P outputs a 24V voltage which is divided by a voltage 3535 3015A to provide a second driving voltage of 15V to the gate of the IGBT. According to the virtual short principle, the voltage of the forward input end and the voltage of the reverse input end of the fourth operational amplifier U3015A will eventually form an equipotential, the gate voltage feedback of the IGBT is divided by the third resistor R3022 and the first resistor R3017 to act on the reverse input end of the fourth operational amplifier U3015A and maintain 1.5V, the voltage of the gate of the IGBT is maintained at +15V, and meanwhile, in the process of the gate voltage rising of the IGBT, the second diode D3006 will be cut off at a certain time, so that the first voltage source no longer acts on the gate of the IGBT. In this way, different channels of the second gating switch U3016 are controlled to be gated, so that the voltage source acting on the gate of the IGBT is switched to be the first voltage source or the second voltage source.

In order to accurately sample the saturation voltage drop of the IGBT, the voltage sampling unit of the present embodiment includes: the voltage storage circuit, the third gating switch U3022, the voltage holding circuit and the voltage acquisition circuit; the output ends of the voltage acquisition circuit and the voltage storage circuit are respectively connected with the input end of the second ADC unit U3018, the input end of the voltage storage circuit is connected with the output end of the third gating switch U3022, a first channel selection end SA of the third gating switch U3022 is suspended, a second channel selection end SB of the third gating switch U3022 is connected with the output end of the voltage holding circuit, and the input end of the voltage holding circuit is connected with the output end of the voltage acquisition circuit; the voltage acquisition circuit is used for acquiring the turn-on voltage value of the IGBT, and the third gating switch U3022 is used for gating the output terminal D of the third gating switch U3022 and the second channel selection terminal SB of the third gating switch U3022 after receiving the third control signal, so that the voltage holding circuit stores the acquired turn-on voltage value of the IGBT to the voltage storage circuit in the form of equivalent electric energy.

As shown IN fig. 6a to 6C, 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 inverting input terminal of the fifth operational amplifier U3021A, the output terminal of the fifth operational amplifier U3021A is connected to the first input terminal IN1 of the second ADC unit U3018, the forward input terminal of the fifth operational amplifier U3021A is grounded, the inverting input terminal of the fifth operational amplifier U3021A is connected to the output terminal D of the third gate switch U3022, and the input terminal IN of the third gate switch U3022 is connected to the second forward output terminal of the third monostable multivibrator U1017.

The voltage holding circuit comprises a sixth operational amplifier U3020A, a seventh operational amplifier U3017A, an eighth resistor R3026 and a ninth resistor R3029; the voltage acquisition circuit comprises a tenth resistor R3034 and an eleventh resistor R3035. A first end of a tenth resistor R3034 is connected to the collector C of the IGBT and the inverting input terminal of the seventh operational amplifier U3017A, a second end of the tenth resistor R3034 is connected to a first end of an eleventh resistor R3035 and is connected to the second input terminal IN0 of the second ADC unit U3018, a 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, an output end of the seventh operational amplifier U3017A is connected to a second end of the ninth resistor R3029, a first end of the ninth resistor R3029 is connected to the forward input terminal of the sixth operational amplifier U3020A, an inverting input terminal of the sixth operational amplifier U3020A is connected to the output terminal thereof and the output terminal thereof is connected to the second channel selection terminal SB of the third gate switch U3022, and an 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.

When the IGBT is controlled to operate IN a linear region, the voltage between the collector and the emitter of the IGBT is large, the voltage is divided and sampled by the eighth resistor R3026 and the ninth resistor R3029, the collected voltage is transmitted to the MCU through the second input terminal IN0 of the second ADC unit U3018, and the collected voltage is transmitted to the output terminal of the fifth operational amplifier U3021A through the seventh operational amplifier U3017A, the eighth resistor R3026, and the ninth resistor R3029 and is applied to both ends of the second capacitor C3055.

Since the enable terminal EN of the third gating switch U3022 is grounded, the first channel selection terminal SA of the third gating switch U3022 and the output terminal D of the third gating switch U3022 are gated when the third gating switch U3022 does not receive the third control signal. When the input terminal IN of the third gating switch U3022 receives the third control signal, the second channel selection terminal SB of the third gating switch U3022 and the output terminal D of the third gating switch U3022 are gated, 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 that 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 loop, the voltage of the second capacitor C3055 is maintained, and since saturation conduction has been entered for a certain period of time, the voltage applied across the second capacitor C3055 at this time, i.e. the saturation voltage drop between the emitter and the collector of the IGBT, is supplied to the MCU for reading.

In summary, the IGBT driving circuit according to the embodiment can effectively control the operating state of the IGBT to switch between the linear region and the saturation region according to the control signal, so as to calibrate the corresponding relationship between the saturation voltage drop and the junction temperature of the IGBT by controlling the IGBT to operate in the saturation region, obtain the power loss of the IGBT by controlling the IGBT to operate in the linear region, acquire the saturation voltage drop of the IGBT by switching to the same condition as the corresponding relationship between the saturation voltage drop and the junction temperature of the calibrated IGBT after obtaining the power loss of the IGBT, calibrate the corresponding relationship between the power loss and the saturation voltage drop of the IGBT, and further convert to obtain the corresponding relationship between the power loss and the saturation voltage drop of the IGBT, so that in practical application, the corresponding junction temperature can be obtained by detecting the power loss of the IGBT, without additionally adding a detection circuit in the control system, thereby reducing the cost of the control system, and facilitating automatic control, calibration and test of the junction temperature of the IGBT The measurement of IGBT junction temperature calibration is standardized, so that the test result is more accurate, and the test efficiency is higher. Meanwhile, the IGBT driving circuit of the embodiment realizes isolation driving of the IGBT through the discrete device, the system is stable, the driving mode is more flexible, and compared with an integrated circuit, the IGBT driving circuit has a wider power range and larger driving capability.

While the embodiments of the present invention have been described in detail with reference to the accompanying drawings, the embodiments of the present invention are not limited to the details of the above embodiments, and various simple modifications can be made to the technical solution of the embodiments of the present invention within the technical idea of the embodiments of the present invention, and the simple modifications are within the scope of the embodiments of the present invention.

It should be noted that the various features described in the above embodiments may be combined in any suitable manner without departing from the scope of the utility model. In order to avoid unnecessary repetition, the embodiments of the present invention will not be described separately for the various possible combinations.

In addition, any combination of the various embodiments of the present invention is also possible, and the same shall be considered as disclosed in the embodiments of the present invention as long as it does not depart from the spirit of the embodiments of the present invention.

Claims

1. An IGBT driving circuit characterized by comprising:

a gate switch U3016 and a voltage switching circuit;

2. The IGBT driver circuit according to claim 1, further comprising:

3. The IGBT driver circuit according to claim 1, wherein the voltage switching circuit comprises:

an amplifying sub-circuit and a switching sub-circuit;

4. The IGBT driving circuit according to claim 3, wherein the amplifying sub-circuit comprises an operational amplifier U3015A and a diode D3005, a forward input terminal of the operational amplifier U3015A is connected to an output terminal of the gating switch U3016, an anode of the diode D3005 is connected to a reverse input terminal of the operational amplifier U3015A, and a cathode of the diode D3005 is connected to an output terminal of the operational amplifier U3015A.

5. The IGBT drive circuit of claim 4, wherein the switch sub-circuit comprises:

6. The IGBT drive circuit of claim 5, wherein the amplification sub-circuit further comprises:

a resistor R3017, a resistor R3022 and a capacitor C3057;

the capacitor C3057 is connected in parallel with the resistor R3022.

7. The IGBT drive circuit of claim 5, wherein the switch sub-circuit further comprises:

a diode D3006, a resistor R3027, and a resistor R3028;

8. The IGBT driver circuit of claim 7, wherein the switch sub-circuit further comprises: