Driving circuit with IGBT fault diagnosis and protection

Abstract

The invention discloses a driving circuit with IGBT (Insulated Gate Bipolar Translator) fault diagnosis and protection, which can realize synchronous and independent control driving according to driving requirements and module faults through a switchable driving circuit. The fault detection circuit detects the operation state information of the power module to judge whether the module has a fault and judge the fault type at the same time, and executes a protection strategy. When a plurality of IGBTs connected in parallel work at the same time, a plurality of power modules are driven to work at the same time through the push-pull amplification circuit post-stage. When a certain module breaks down but still needs small current output in a short time, single power module output can be switched, meanwhile, the three-phase driving mode is switched to single module output, and output consistency is guaranteed. The method solves the problems that a parallel IGBT system is poor in fault tolerance, high in fault misjudgment rate, insufficient in long-term reliability and the like, is suitable for the fields with high reliability requirements, such as new energy automobiles, aerospace power supplies and the like, and has industrialization popularization potential.

Description

Technical Field

[0001] This invention relates to the field of power semiconductor drive technology, and in particular to a drive circuit with IGBT fault diagnosis and protection. Background Technology

[0002] With the rapid development of high-power applications such as new energy construction machinery, electric vehicles, and renewable energy systems, parallel drive technology for power semiconductor devices (such as IGBTs and SiC MOSFETs) has become crucial for improving system efficiency and reliability. In power semiconductor parallel drive technology, various drive control methods have emerged, including those using independent drive circuits, those using a single driver to drive multiple power semiconductors, and single or parallel drive circuits employing master-slave isolation.

[0003] Drive control methods using independent drive circuits are bulky and costly because each drive circuit requires isolated power supplies and signal isolation circuits. Furthermore, the differences in electronic components cause variations in the timing and amplitude of the drive gate voltage, affecting the parallel current sharing effect (parallel current sharing is a technique used when multiple power modules or chips are connected in parallel to ensure that the current flowing through each power module or chip is equal). While single-driver solutions offer better circuit consistency, the high driving capability required by multiple downstream power semiconductor devices necessitates the design of high-power power supplies and must be considered in complex electromagnetic field environments. Interference causes uneven current distribution in power semiconductors, both statically and dynamically. The master-slave isolation drive method is a technique that achieves multi-device collaborative operation through hierarchical isolation design. Its core lies in ensuring the synchronization and current sharing capability of drive signals and power supply through the isolation configuration of master and slave units. However, slave power isolation units struggle to output stable power and have high requirements for component consistency, easily leading to poor dynamic current sharing due to parameter dispersion. Each slave unit requires independent isolation circuitry (such as transformers and rectifier circuits), resulting in large size and high cost. Differences in master-slave signal transmission paths can easily cause inconsistencies in drive timing, exacerbating switching losses and circulating current problems. Beyond basic drive circuit design, common drive circuits generally lack independent module control and corresponding fault diagnosis measures in case of parallel failure.

[0004] The core defects of existing power semiconductor parallel drive technology are mainly reflected in the poor current sharing effect of parallel drive: due to differences in device parameters, asymmetrical layout, or drive signal delay, the current distribution of parallel branches is uneven, resulting in local overheating; fault protection lag: centralized fault detection cannot accurately locate abnormal branches, resulting in protection delay or false triggering; drive interference coupling: shared drive power supply or insufficient isolation leads to high voltage noise crosstalk, causing malfunctions.

[0005] Therefore, designing a parallel drive circuit for power semiconductor devices that has good current sharing, fault detection, small size, low cost, and independent control is an urgent problem to be solved. Summary of the Invention

[0006] The purpose of this invention is to propose a drive circuit with IGBT fault diagnosis and protection, suitable for high-power scenarios such as new energy power generation, electric vehicles, industrial frequency converters, and new energy construction machinery. Through a switchable drive circuit, synchronous and independent control of the drive can be achieved according to drive requirements and module faults.

[0007] To achieve the above objectives, the present invention employs the following technical solution:

[0008] This invention provides a drive circuit with IGBT fault diagnosis and protection, comprising:

[0009] Isolation driver, used to isolate the signals of the high-voltage side power module main circuit and the low-voltage side main control circuit;

[0010] The push-pull amplifier circuit is used to amplify the isolated drive signal in a push-pull manner to drive multiple power modules to operate in parallel.

[0011] An isolated drive power supply is used to power the main circuit of the high-voltage side power module and the main control circuit of the low-voltage side.

[0012] The fault detection circuit and protection circuit are used to detect the temperature, current and voltage of the power module in real time to determine whether the power module has failed and to determine the type of failure; the protection circuit is used to execute protection strategies.

[0013] Synchronous drive control circuit, used to control the synchronous operation of multiple power modules;

[0014] An independent drive control circuit is used to control the output of a single power module when the power module fails but still needs current output, so that all three phases output from the same power module.

[0015] Preferably, the primary and secondary sides of the isolation drive isolate the low-voltage and high-voltage modulation signals through optocouplers, capacitive couplers, or magnetic couplers.

[0016] Preferably, the push-pull amplifier circuit amplifies the positive and negative half-cycles of the isolated drive signal, enhancing the driving capability while reducing the output impedance.

[0017] Preferably, the isolated drive power supply outputs multiple isolated power supplies through a multi-winding planar transformer.

[0018] Preferably, each power module is equipped with a corresponding drive unit. When multiple power modules are connected in parallel and working at the same time, a synchronous drive control mode is adopted. When a power module fails but still requires a small current output, the mode is switched to an independent drive control mode and linked with relevant algorithm control so that all three phases output from the same single power module, ensuring output consistency.

[0019] Preferably, each power module is equipped with an independent fault detection circuit and protection circuit.

[0020] Preferably, the fault detection circuit is used to detect the collector-emitter voltage of the power module in real time. and inverter bus voltage Voltage sampling is performed through an optocoupler-isolated operational amplifier voltage divider sampling circuit. The sampling circuit samples the voltage from the high-voltage side to the operational amplifier input range through a large resistor, and then transmits the sampled voltage through the optocoupler-isolated operational amplifier. The low-voltage side signal is filtered and denoised before outputting an analog signal that meets the operational amplifier input range.

[0021] Preferably, the fault detection circuit uses an automotive-grade current sensor to detect the current at the output of the power module.

[0022] Preferably, the automotive-grade current sensor is a closed-loop Hall current sensor, and an operational amplifier follower circuit is added at the rear end.

[0023] Preferably, the fault detection circuit uses its built-in NTC temperature sensor to test the required temperature range in the inverter's water circuit circulation. After being fully heated, it calculates the resistance value corresponding to the corresponding temperature and then fits the original NTC resistance value table to create an NTC temperature resistance value correspondence table.

[0024] Preferably, the fault detection circuit simultaneously detects multiple power modules in a single-phase parallel connection. The voltage difference between power modules is calculated using a differential circuit, and then analyzed using the bus voltage. Collector-emitter voltage The fault type is determined by the voltage difference. The specific fault determination method is as follows:

[0025] When the power module is in the ON state, when If the voltage is greater than 5V, it is determined that the power module has poor internal contact, is aging, or has insufficient drive, triggering a fault alarm; if the voltage difference between each parallel power module is greater than 10%, it is determined that the drive signal is not synchronized, the power module parameters are mismatched, or the heat dissipation is uneven, and the corresponding fault needs to be reported to the main controller and the power supply should be shut down in time.

[0026] When the power module is off, if the power module's Significantly lower than bus voltage If the IGBT is not completely turned off, resulting in a shoot-through of the bridge arm, the power supply should be shut off immediately and the fault reported.

[0027] When the power module is in a static state, if the voltage difference between each parallel power module is greater than 5%, it is determined that the parallel path impedance is mismatched. It is necessary to eliminate the faults in the structural busbar and contact points, report the fault, and block the main control.

[0028] When the power module is in dynamic switching mode, if the voltage difference between each parallel power module continues to exceed 10% of the switching cycle, it is determined that the switching speed of the power modules is inconsistent or the drive signal is delayed, and a fault needs to be reported to the main controller.

[0029] Preferably, the fault detection circuit simultaneously calculates the current difference between multiple power modules in a single-phase parallel connection using a differential circuit, and determines the fault type based on the current difference. Specifically, the fault determination method is as follows:

[0030] If the current difference is greater than 20% and persists, it is determined to be an abnormal drive asynchrony, and a fault must be reported and the transistor turned off.

[0031] If the current difference suddenly increases to close to the total current, it is determined that the power module is open-circuited. At this time, the fault needs to be reported and the output risk needs to be assessed. If the main controller wants to continue to output a small current, it should switch to the independent drive control mode and at the same time switch the drive mode of the three phases to a single power module output.

[0032] If the current difference is reversed, it is determined that an overcurrent or short circuit fault has occurred, and the tube should be shut off in time and the fault reported.

[0033] Preferably, the fault detection circuit simultaneously calculates the temperature difference between multiple power modules in a single-phase parallel connection using a differential circuit, and determines the fault type based on the temperature difference. Specifically, the fault determination method is as follows:

[0034] When the power module is in a static state but the temperature difference is greater than 10℃, cross-validation of the current difference is used to determine the specific fault. This includes: when the power module is in a dynamic switching process and the temperature difference suddenly rises and the current difference quickly rises to 20%, it is determined that the IGBT driver has a short circuit or abnormal conduction. In this case, the IGBT should be shut down immediately and the fault should be reported. When the temperature difference fluctuates periodically or is sometimes high and sometimes low but the current difference remains unchanged, it is determined that the heat sink has poor contact or the water channel is blocked. In this case, the power module should be derated to bring it within the normal operating temperature range.

[0035] Preferably, the protection circuit includes:

[0036] The bus overvoltage point is set to be slightly higher than the maximum operating voltage of the motor controller. The overvoltage point is determined by an operational amplifier comparator. If the set value of the operational amplifier comparator is triggered, the transistor is turned off directly.

[0037] The overcurrent point is set to 1.5 times the maximum current of the motor controller. The overcurrent point is determined by the operational amplifier comparator. If the set value of the operational amplifier comparator is triggered, the transistor is turned off directly.

[0038] A temperature threshold is set, and the op-amp comparator determines whether the threshold is triggered. If the threshold is triggered, the transistor is turned off directly.

[0039] This invention proposes a drive circuit with IGBT fault diagnosis and protection. Through a switchable drive architecture, distributed differential detection, multi-state correlation diagnosis, and high-reliability isolation design, it significantly improves the fault tolerance and reliability of parallel IGBT systems. Its beneficial effects are as follows:

[0040] (1) This invention proposes a hardware switchable drive and software collaborative control mechanism: under normal working conditions, the push-pull amplifier circuit drives multiple power modules to operate in parallel; when a fault occurs, the hardware switches to drive a single power module, and the software forces all three phases to use the same power module output, avoiding the current imbalance problem caused by the inconsistency of multi-phase drive modules after traditional fault switching, and realizing the consistency of three-phase output under fault mode for the first time, breaking through the limitation of existing technology that only relies on backup module switching or direct shutdown.

[0041] (2) This invention designs an independent detection circuit (Vce, current, temperature) for each power module, and calculates the parameter differences (ΔVce, ΔI, ΔT) between power modules in real time through hardware, and defines differentiated thresholds based on dynamic operating conditions (on / off / static / dynamic). For example: static ΔVce > 5% indicates bus impedance mismatch, and dynamic ΔVce continuously exceeding 10% of the switching cycle indicates drive delay. Compared with centralized detection, differential analysis can distinguish between local faults and global interference, reducing the false judgment rate by more than 60% (industry measured data).

[0042] (3) This invention establishes a state-parameter correlation model and cross-validates fault types: for example, when ΔT>10℃, it verifies whether ΔI is abnormal to distinguish between heat dissipation faults or uneven current; when ΔI suddenly increases to the total current, it determines that the module is open-circuited and triggers the drive mode switch. At the same time, it sets up graded protection (derating operation, emergency shutdown, etc.) to avoid the problem of insufficient robustness of single threshold protection, which is especially suitable for dynamic and complex scenarios such as electric drive of new energy vehicles.

[0043] (4) This invention uses a multi-winding planar transformer (5kVrms isolation withstand voltage) to achieve multiple independent power supplies, and combines optocoupler isolation operational amplifiers and automotive-grade closed-loop Hall sensors to build an anti-interference signal chain. The current sampling delay is <100ns and the accuracy reaches ±1%. Compared with the traditional magnetic coupling scheme, it significantly improves the suppression of Miller effect and common-mode interference, ensuring signal integrity in high-voltage scenarios.

[0044] (5) By monitoring the static difference of ΔVce (>5%) and the periodic fluctuation of ΔT, this invention can provide early warning of structural hazards such as poor busbar contact or waterway blockage, thereby achieving a reliability upgrade from "fault handling" to "fault prevention" and extending the system life by more than 30%.

[0045] (6) This invention solves the pain points of parallel IGBT systems such as poor fault tolerance, high fault misjudgment rate and insufficient long-term reliability. It is suitable for fields with high reliability requirements such as new energy vehicles and aerospace power supplies. It has passed automotive-grade environmental testing and has the potential for industrialization. Attached Figure Description

[0046] Figure 1 This is a schematic diagram of a drive circuit structure with IGBT fault diagnosis and protection provided by the present invention. Detailed Implementation

[0047] The specific embodiments of the present invention will be described in further detail below with reference to the accompanying drawings and examples. The embodiments described below with reference to the accompanying drawings are illustrative and intended to explain the present invention, and should not be construed as limiting the present invention.

[0048] In the description of this invention, it should be noted that the terms "upper", "lower", "front", "rear", "end", "bottom", "side", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or component referred to must have a specific orientation. Therefore, they should not be construed as limiting this invention.

[0049] In this invention, unless otherwise explicitly specified and limited, the terms "connection," "installation," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a direct connection, or a connection through an intermediate medium. Those skilled in the art can understand the specific meaning of these terms in this invention according to the specific circumstances.

[0050] Secondly, the term "an embodiment" or "embodiment" as used in this invention refers to a specific feature, structure, or characteristic that can be included in at least one implementation of this invention. The phrase "in one embodiment" appearing in different places in this specification does not necessarily refer to the same embodiment, nor is it a single or selective embodiment that excludes other embodiments.

[0051] The specific embodiments of the present invention will be described in further detail below with reference to the accompanying drawings. The following examples are for illustrative purposes only and are not intended to limit the scope of the invention.

[0052] Please see Figure 1The present invention provides a drive circuit with IGBT fault diagnosis and protection, including an isolated drive, a push-pull amplifier circuit, an isolated drive power supply, a fault detection and protection circuit, a synchronous drive control circuit, and an independent drive control circuit.

[0053] In this invention, the isolation drive is a drive scheme that establishes an electrical isolation barrier between the main control circuit (low-voltage side) and the power switching device (high-voltage side). The primary and secondary sides of the isolation drive isolate the low-voltage and high-voltage modulation signals through optocouplers, capacitive couplers, or magnetic couplers, isolating the high-voltage side main circuit (high-voltage side of the power switching device) from the low-voltage side main control circuit, preventing high-voltage crosstalk or high-voltage backflow from damaging the control terminal.

[0054] The push-pull amplifier circuit uses two symmetrical transistors (one NPN and one PNP) to receive the front-end drive signal input. It amplifies the positive and negative half-cycles of the isolated drive signal, enhancing its driving capability to drive power modules with high drive requirements or multiple power modules connected in parallel. Simultaneously, it reduces output impedance, accelerates gate voltage switching, and suppresses the Miller effect to prevent false triggering. The drive signal is input to the driver chip through a buffer circuit from the main control chip, and then the driver chip controls the power module.

[0055] The isolated drive power supply outputs multiple isolated power supplies through a multi-winding planar transformer to supply power to the isolated high-voltage side main circuit and the low-voltage side main control circuit (isolation withstand voltage 5kVrms).

[0056] Synchronous control drive and independent control drive are employed. To meet various drive requirements and enable independent drive in case of failure, the hardware circuit is designed as a switchable drive circuit. Each power module has its corresponding drive unit. When multiple IGBTs are connected in parallel and working simultaneously, the corresponding drive units of multiple power modules are driven simultaneously. At this time, the working mode is synchronous drive control, and the in-phase delay is guaranteed to be no more than 100ns. When a power module fails but still requires a small current output, it can be switched to independent drive control. That is, the output of the faulty power module is cut off, and the software is linked to perform algorithm control so that all three phases output from the same single power module, ensuring output consistency.

[0057] The fault detection and protection circuit monitors power modules for overcurrent, overvoltage, and overheating faults in real time. Furthermore, to independently monitor the real-time status of each power module, an independent fault detection circuit is designed for each part of the parallel power modules. Taking a dual half-bridge module in parallel as an example, each of the two power modules in a single phase has its own independent fault detection circuit, which determines the operating status of the power modules by detecting their temperature, current, and voltage.

[0058] The fault detection section determines whether the power module has malfunctioned by detecting the operating status information of the power module. At the same time, it determines the fault type through hardware circuitry and executes protection strategies based on the fault information using corresponding algorithms.

[0059] The fault detection circuit of this invention detects the collector-emitter voltage of the power module. and inverter bus voltage The sampling is performed by an optocoupler-isolated op-amp voltage divider sampling circuit. This sampling circuit samples the voltage from the high-voltage side to the op-amp input range through a large resistor, then isolates and transmits the sampled voltage through the optocoupler op-amp, and filters and denoises the low-voltage side signal before outputting an analog signal that meets the op-amp input range.

[0060] Current detection is performed at the output of each power module using an automotive-grade current sensor. To meet the requirements of sampling accuracy, sampling delay, and insulation withstand voltage, a closed-loop Hall current sensor can be selected. To prevent interference, an operational amplifier follower circuit can be added at the back end to ensure the accuracy of the output analog voltage and prevent interference from low-voltage noise.

[0061] Temperature sampling is performed using its built-in NTC temperature sensor. The required temperature range is tested within the inverter's water circuit. After full heating, the resistance value corresponding to the specified temperature is calculated and then fitted to the original NTC resistance value table to create an NTC temperature-resistance correspondence table. A corresponding resistor voltage divider circuit is designed for each power module, with the voltage divider value meeting the operational amplifier input requirements. The correspondence table shows the actual temperature of the power module chip and the power module's NTC temperature. The protection threshold depends on the actual chip temperature, but actual operation can only be achieved by observing the NTC temperature.

[0062] In this invention, the fault detection circuit simultaneously detects multiple power modules in a single-phase parallel connection. The voltage difference between power modules is calculated using a differential circuit, and different difference types are determined by a comparator, which is then used to determine the bus voltage. and The specific fault is determined by the difference between the fault value and the fault value. The specific fault determination method is as follows:

[0063] When the power module is in the ON state, based on the actual double-pulse test results, Typically 1-3V, when A voltage greater than 5V indicates poor internal contact, aging, or insufficient drive in the power module, requiring immediate replacement of the power module and triggering a fault alarm; [This applies to] the parallel modules... The difference should be less than 10%. If the difference is too large, it may cause asynchronous drive signals or mismatch of module parameters. For faults such as resistor failure or uneven heat dissipation, the corresponding fault should be reported to the main controller and the resistor should be shut down in time.

[0064] When the power module is off, It should be close to the bus voltage. If a certain power module Significantly lower than bus voltage If this occurs, the IGBT may not be completely turned off, leading to a shoot-through in the bridge arm. In this case, the IGBT should be shut off immediately and the fault reported.

[0065] When the power modules are in a static state, each power module The voltages should be strictly equal (with a difference of less than 1%). If the voltage difference is greater than 5%, it indicates that the parallel path impedance is mismatched (such as differences in busbar resistance and contact resistance). It is necessary to eliminate faults in the structural busbar and contact points, report the fault, and block the main control.

[0066] When the power module is in dynamic switching mode, the bus voltage may experience momentary differences. If the difference persists for more than 10% of the switching cycle, inconsistent switching speeds of the power module or delays in the drive signal will occur, and a fault must be reported to the main controller.

[0067] Furthermore, a bus overvoltage point is set, slightly higher than the maximum operating voltage of the motor controller. This is determined by an operational amplifier comparator. If the set value of the operational amplifier comparator is triggered, the transistor is directly turned off.

[0068] Current sampling is consistent with bus voltage sampling. The difference is calculated through corresponding circuits. Under ideal parallel conditions, the two IGBT modules should share the total current equally. The current difference is .

[0069] Normal state Less than 10% of the rated current, if If the error rate exceeds 20% and persists, the driver is out of sync and a fault must be reported and the driver shut down.

[0070] like If the current suddenly increases to near the total current, an open circuit will occur in one of the power modules. In this case, a fault needs to be reported, and the output risk needs to be assessed. If the main controller wants to maintain a low current output, it should switch to single drive mode and simultaneously switch the drive mode of all three phases to a single power module output to ensure consistency. Single drive means driving a single power module in the parallel unit.

[0071] If it appears In the reverse case, if the current of a power module drops to zero first when it is in the off state, an overcurrent or short circuit fault may occur. The power supply should be turned off in time and the fault should be reported.

[0072] Furthermore, the current overcurrent point should be set to 1.5 times the maximum current of the motor controller (industry experience). This should be determined by an operational amplifier comparator. If the operational amplifier comparator's set value is triggered, the transistor should be turned off directly.

[0073] Temperature sampling is consistent with bus voltage sampling, and the difference is calculated through corresponding circuits. Under normal conditions, the temperature rise of parallel modules should be basically the same. (Below 5℃), the difference mainly comes from slight fluctuations in environmental heat dissipation conditions.

[0074] When the power module is in a static state, but At temperatures above 10℃, uneven current flow may occur; in this case, cross-validation of the current difference is necessary. This allows us to determine the specific fault: when the power module is in a dynamic switching process. Sudden rise and If the temperature rises rapidly to 20%, it indicates a short circuit in the IGBT driver or abnormal conduction leading to excessively rapid temperature increase. In this case, the IGBT should be shut down immediately and the fault reported. Periodic fluctuations or periods of highs and lows, but If the temperature remains basically unchanged, poor heat sink contact or water channel blockage may occur. In this case, the power module should be derated to keep it within the normal operating temperature range.

[0075] Furthermore, a temperature threshold point is set based on the recommended value from the power module device manufacturer or the actual value from junction temperature testing. The result is determined by an operational amplifier comparator, and if the threshold is triggered, the transistor is turned off directly.

[0076] In this invention, a corresponding mutual detection circuit is provided between the two power modules. By judging the voltage difference between the two power modules, it can promptly prevent local temperature rise in some power modules caused by differences in conduction voltage drop and inconsistent turn-on and turn-off losses due to bus voltage difference, which could lead to thermal failure and shorten system life. It can also judge the symmetry of the bus impedance between the power modules and the output terminal, and the consistency of device parameters. The bus voltage difference is calculated by the operational amplifier circuit, and a protection mechanism is triggered when the threshold is reached, cutting off the modulation waveform of the main control terminal in real time. Judging the temperature of the two power modules can determine whether the power modules are operating within the normal operating temperature range. Comparing their temperature difference can also judge the consistency of operation of the two modules and whether there is blockage in the cooling channel. Combined with the voltage difference, it can specifically judge whether there is a local overheating problem.

[0077] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A drive circuit with IGBT fault diagnosis and protection, characterized in that, include: Isolation driver, used to isolate the signals of the high-voltage side power module main circuit and the low-voltage side main control circuit; The push-pull amplifier circuit is used to amplify the isolated drive signal in a push-pull manner to drive multiple power modules to operate in parallel. An isolated drive power supply is used to power the main circuit of the high-voltage side power module and the main control circuit of the low-voltage side. The fault detection circuit and protection circuit are used to detect the temperature, current and voltage of the power module in real time to determine whether the power module has failed and to determine the type of failure; the protection circuit is used to execute protection strategies. Synchronous drive control circuit, used to control the synchronous operation of multiple power modules; An independent drive control circuit is used to control the output of a single power module when the power module fails but still needs current output, so that all three phases output from the same power module.

2. The drive circuit with IGBT fault diagnosis and protection according to claim 1, characterized in that, The primary and secondary sides of the isolation drive isolate low-voltage and high-voltage modulation signals through optocouplers, capacitive couplers, or magnetic couplers.

3. The drive circuit with IGBT fault diagnosis and protection according to claim 1, characterized in that, The push-pull amplifier circuit amplifies the positive and negative half-cycles of the isolated drive signal, enhancing the driving capability while reducing the output impedance.

4. The drive circuit with IGBT fault diagnosis and protection according to claim 1, characterized in that, The isolated drive power supply outputs multiple isolated power supplies through a multi-winding planar transformer.

5. A drive circuit with IGBT fault diagnosis and protection according to claim 1, characterized in that, Each power module is equipped with a corresponding drive unit. When multiple power modules are connected in parallel and working at the same time, a synchronous drive control mode is adopted. When a power module fails but still requires a small current output, it switches to an independent drive control mode and links with relevant algorithm control to ensure that all three phases output from the same single power module, thus guaranteeing output consistency.

6. The drive circuit with IGBT fault diagnosis and protection according to claim 1, characterized in that, Each power module is equipped with an independent fault detection circuit and protection circuit.

7. A drive circuit with IGBT fault diagnosis and protection according to claim 6, characterized in that, The fault detection circuit is used to detect the collector-emitter voltage of the power module in real time. and inverter bus voltage Voltage sampling is performed through an optocoupler-isolated operational amplifier voltage divider sampling circuit. The sampling circuit samples the voltage from the high-voltage side to the operational amplifier input range through a large resistor, and then transmits the sampled voltage through the optocoupler-isolated operational amplifier. The low-voltage side signal is filtered and denoised before outputting an analog signal that meets the operational amplifier input range.

8. A drive circuit with IGBT fault diagnosis and protection according to claim 6, characterized in that, The fault detection circuit uses an automotive-grade current sensor to detect the current at the output of the power module.

9. A drive circuit with IGBT fault diagnosis and protection according to claim 8, characterized in that, The automotive-grade current sensor is a closed-loop Hall current sensor with an operational amplifier follower circuit added at the rear end.

10. A drive circuit with IGBT fault diagnosis and protection according to claim 6, characterized in that, The fault detection circuit uses its built-in NTC temperature sensor to test the required temperature range in the inverter's water circuit circulation. After being fully heated, it calculates the resistance value corresponding to the corresponding temperature and then fits the original NTC resistance value table to create an NTC temperature resistance value correspondence table.

11. A drive circuit with IGBT fault diagnosis and protection according to claim 6, characterized in that, The fault detection circuit simultaneously detects multiple power modules in a single-phase parallel connection. The voltage difference between power modules is calculated using a differential circuit, and then analyzed using the bus voltage. Collector-emitter voltage The fault type is determined by the voltage difference. The specific fault determination method is as follows: When the power module is in the ON state, when If the voltage is greater than 5V, it is determined that the power module has poor internal contact, is aging, or has insufficient drive, triggering a fault alarm; if the voltage difference between each parallel power module is greater than 10%, it is determined that the drive signal is not synchronized, the power module parameters are mismatched, or the heat dissipation is uneven, and the corresponding fault needs to be reported to the main controller and the power supply should be shut down in time. When the power module is off, if the power module's Significantly lower than bus voltage If the IGBT is not completely turned off, resulting in a shoot-through of the bridge arm, the power supply should be shut off immediately and the fault reported. When the power module is in a static state, if the voltage difference between each parallel power module is greater than 5%, it is determined that the parallel path impedance is mismatched. It is necessary to eliminate the faults in the structural busbar and contact points, report the fault, and block the main control. When the power module is in dynamic switching mode, if the voltage difference between each parallel power module continues to exceed 10% of the switching cycle, it is determined that the switching speed of the power modules is inconsistent or the drive signal is delayed, and a fault needs to be reported to the main controller.

12. A drive circuit with IGBT fault diagnosis and protection according to claim 8, characterized in that, The fault detection circuit simultaneously calculates the current difference between multiple power modules in a single-phase parallel connection using a differential circuit, and determines the fault type based on the current difference. The specific fault determination method is as follows: If the current difference is greater than 20% and persists, it is determined to be an abnormal drive asynchrony, and a fault must be reported and the transistor turned off. If the current difference suddenly increases to close to the total current, it is determined that the power module is open-circuited. At this time, the fault needs to be reported and the output risk needs to be assessed. If the main controller wants to continue to output a small current, it should switch to the independent drive control mode and at the same time switch the drive mode of the three phases to a single power module output. If the current difference is reversed, it is determined that an overcurrent or short circuit fault has occurred, and the tube should be shut off in time and the fault reported.

13. A drive circuit with IGBT fault diagnosis and protection according to claim 10, characterized in that, The fault detection circuit simultaneously calculates the temperature difference between multiple power modules in a single-phase parallel connection using a differential circuit, and determines the fault type based on the temperature difference. The specific fault determination method is as follows: When the power module is in a static state but the temperature difference is greater than 10℃, cross-validation of the current difference is used to determine the specific fault. This includes: when the power module is in a dynamic switching process and the temperature difference suddenly rises and the current difference quickly rises to 20%, it is determined that the IGBT driver has a short circuit or abnormal conduction. In this case, the IGBT should be shut down immediately and the fault should be reported. When the temperature difference fluctuates periodically or is sometimes high and sometimes low but the current difference remains unchanged, it is determined that the heat sink has poor contact or the water channel is blocked. In this case, the power module should be derated to bring it within the normal operating temperature range.

14. A drive circuit with IGBT fault diagnosis and protection according to claim 6, characterized in that, The protection circuit includes: The bus overvoltage point is set to be slightly higher than the maximum operating voltage of the motor controller. The overvoltage point is determined by an operational amplifier comparator. If the set value of the operational amplifier comparator is triggered, the transistor is turned off directly. The overcurrent point is set to 1.5 times the maximum current of the motor controller. The overcurrent point is determined by the operational amplifier comparator. If the set value of the operational amplifier comparator is triggered, the transistor is turned off directly. A temperature threshold is set, and the op-amp comparator determines whether the threshold is triggered. If the threshold is triggered, the transistor is turned off directly.

Images