1. Introduction In recent years, the novel power switching device IGBT has gradually gained recognition. Compared with previous power electronic devices, IGBTs have the following characteristics: high input impedance, allowing for the use of universal and low-cost drive circuits; high-speed switching characteristics; and low losses in the on-state. IGBTs have significant advantages in overall performance and are widely used in various power conversion devices with operating frequencies of tens of kilohertz and output power ranging from several kilowatts to tens of kilowatts. When designing the drive circuit, the following parameters are mainly considered: IGBT rating, short-circuit current characteristics, turn-off characteristics of inductive loads, maximum gate-emitter voltage, gate input capacitance, and safe operating area characteristics. The input and output of optocoupler-driven devices are both active, and the width of their positive and negative latch-up pulses is unrestricted. Overcurrent and short-circuit protection can be easily achieved by detecting the IGBT's on-state collector voltage, and an overcurrent alarm signal can be sent to the microprocessor. 2. IGBT Lower Arm Driver Device HCPL-316J Key features of HCPL-316J: 16-pin dual in-line package; drives 150 A/1200 V IGBTs; wide power supply voltage range of 15 V to 30 V; maximum switching time of 0.5 μs; dead time of 2 μs; CMOS/TTL level compatible; optical isolation and fault status feedback; IGBT "soft" turn-off; VCE undersaturation detection and hysteresis undervoltage lockout protection; user-configurable automatic reset and automatic shutdown. Minimum common-mode rejection of 15 kV/μs (at VCM=1500 V); overcurrent shutdown and undervoltage lockout functions; automatically locks out all outputs and issues an alarm signal when there is overcurrent or VCC undervoltage; when the high-side floating bias voltage source is undervoltage, it can lock out 3 high-side outputs through its internal undervoltage lockout circuit. HCPL-316J features overcurrent detection and undervoltage lockout output functions. In case of overcurrent, a fault signal is output, and the IGBT is soft-shutdown. The power supply voltage range is 15 V to 30 V. At VCM = 1500 V, the minimum common-mode rejection (CMR) voltage is 15 kV/μs. The user can set positive/negative logic input, automatic reset, and automatic shutdown. Figure 1 shows the internal structure of the HCPL-316J. The optocoupler LED1 forms the input control circuit, with VIN+ and VIN- being the positive/negative logic input terminals, respectively. When a negative logic signal is input, VIN+ is set to high, and VIN- is connected to the input signal; conversely, when a positive logic signal is input, VIN- is set to low, and VIN+ is connected to the input signal. The input signal gate circuit is transmitted by LED1 to the internal driver circuit and converted into the gate drive signal of the IGBT. The fault signal control circuit, composed of optocoupler LED2 and other components, has pin 7 floating and pin 8 grounded. VCC1 and GND1 are the input power supplies, VCC2 and VEE are the output power supplies, and VC is the power supply for the collector of the push-pull output transistor, which can be directly connected to VCC2 or connected in series with a resistor RC to limit the output conduction current. VOUT is the gate drive voltage output terminal. This system can quickly and effectively protect the driven IGBT from overcurrent in the driven power device or from a power supply failure in the gate drive circuit itself. This series of drivers requires only a non-isolated +15V power supply; it features high dv/dt capacity; comprehensive protection functions; fault memory, notifying the control system via a FAULT signal; upper and lower interlocks to prevent two IGBTs on the same bridge arm from turning on simultaneously; and an externally adjustable gate resistor, allowing operation at higher switching frequencies and achieving high conversion efficiency with IGBTs of different power ratings. The fault protection circuit, composed of LED2 and other components, uses DESAT as the overcurrent detection input, connected to the IGBT collector via a series resistor and a clamping diode. Under normal conditions, overcurrent faults cannot be detected. FAULT is low, the RS flip-flop output Q remains low, ensuring the input signal passes through LED1, and the fault signal output FAULT is high. The reset terminal RESET has no effect on the input channel. If DESAT detects an overcurrent signal (DESAT voltage exceeds 7V), FAULT is high. This signal, through internal logic, blocks the driver output and the input signal of LED1, and simultaneously turns on LED2. The RS flip-flop output Q is high, and the fault output FAULT is low, notifying the external microcomputer. When an IGBT experiences overcurrent, the driver output level drops, causing the IGBT to soft-turn off, preventing damage due to overvoltage during sudden turn-off. Furthermore, since the fault output FAULT is open-collector, multiple device FAULTs can be connected in parallel to the microcomputer. After a fault occurs, FAULT remains low until the RESET input resets to a low level. When driving IGBTs larger than 150 A/1200 V using a lower arm driver, an external current buffer can be connected to expand its driving capability. As shown in Figure 2, an overcurrent occurs when the DESAT terminal voltage exceeds 7 V. The driving circuit diagram of the IGBT lower arm is shown in Figure 3. In Figure 3, the power supplies +5 V, VB+, and VB- (both VB+ and VB- are 25 V) provide the operating voltage for the device. The potential symbol IGBTBE, connected to pin 16, is connected to the emitter of the lower arm of the IGBT module. IGBTBG1-3, connected to pin 11, are connected to the gate of the lower arm, controlling the IGBT's turn-on and turn-off. When the voltage at pin 14 (DESAT) exceeds 7 V, an overcurrent signal is detected, or VCC is undervoltage. Pin 6 (FAULT) goes low, and the device automatically latches all outputs to protect the IGBT module, while simultaneously sending an alarm signal to the microprocessor. 3. Upper Arm Driver HCPL-3120 The HCPL-3120 upper arm driver consists of a gallium arsenide phosphide optocoupler and a power output circuit. Its main features include: an 8-pin dual in-line package; a maximum peak output current of 2.0 A; a minimum common-mode rejection ratio of 15 kV/μs; a maximum low level of 0.5 V without gate negative voltage; a maximum supply current of 5 mA; a supply voltage range of 15 V to 30 V; a maximum switching speed of 0.5 μs; and hysteresis undervoltage lockout (UVLO) output. The internal block diagram of the HCPL-3120 is shown in Figure 4. The HCPL-3120 output circuit has a wide operating voltage range, making it easy to provide the drive voltage required by gated devices. It is suitable for IGBTs with a rated capacity of 1200 V/100 A. For higher capacity IGBTs, an external current buffer can be added to extend their drive capability. The schematic diagram of the upper arm IGBT drive circuit is shown in Figure 5. [align=center] [/align] In Figure 5. The voltages VU+ and VU- are 25 V. The output terminal (Vo) IGBTTG1 is connected to one gate of the U term in the upper arm of the IGBT module, and IGBTTE1 is connected to the emitter, thereby controlling the IGBT's turn-on and turn-off. 4 Experimental Results and Analysis Figure 6 shows the results obtained from the oscilloscope during testing. The figure shows that the positive drive voltage is +16.5 V and the negative drive voltage is -7.5 V. This method effectively and quickly turns the IGBT on and off, reducing losses during the turn-on and turn-off processes. 5 Conclusion This system design, while fully utilizing and meeting the characteristics and requirements of the IGBT module, focuses on studying the IGBT's drive and protection characteristics. HCPL-316J and HCPL-3120 driving devices were selected for drive and protection, meeting the dynamic requirements of IGBT turn-on and turn-off, thus ensuring high reliability of the IGBT.