Insulated-gate bipolar transistors (IGBTs) always operate in parallel for a large output current in modern high-power converter design. Suppressing dynamic current imbalance of the paralleled IGBTs is crucial for stable operation of converters. Though dynamic current imbalance could be suppressed by the symmetrical power loop design and consistent control signal, there is an inherent parameter difference in the power loop or gate circuit caused by the practical factors such as materials, physical dimensions and installation methods. The inherent difference could be compensated with gate delay control in a certain degree. The voltage and current in the key dynamic phases of IGBT are analyzed to obtain the delay compensation in gate delay control. An asynchronous gate signal driving method based on reference signal selections is proposed to suppress dynamic imbalance of collector current from parallel connected IGBTs, and the implementation of the asynchronous drive is described in brief. By using simulation software, the delay settings and dynamic current imbalance under different parameters discrepancy of drive circuit are obtained. The delay difference from key dynamic phases is calculated as the compensation for balanced dynamic current sharing under two selections of reference signals. Furthermore, the dynamic current distribution in the turn-on and turn-off phases is compensated by the asynchronous drive control. The optimization of asynchronous drive method on dynamic current sharing of paralleled IGBTs is verified by comparing dynamic current imbalance between the system with compensation and the system without compensation.

The electrical parameters of insulated gate bipolar transistor (IGBT) module change over the service life. By detecting the values of these parameters, the aging state of IGBT module can be identified. Bond wire damage is the main characteristic of IGBT module degradation, and the impedance change of bond wire can directly affect the IGBT short-circuit current. In this paper, an IGBT condition monitoring drive circuit based on self-excited short-circuit current is designed. The drive circuit is directly connected to the IGBT module, which can obtain IGBT data from the lowest level and determine the aging state of IGBT most quickly. Firstly, the relationship between IGBT short-circuits current and aging state is analyzed. Through the model establishment and mathematical calculation, it is concluded that the short-circuit current decreases after bond wire damage. Secondly, the self-excited short circuit condition is introduced. By setting the gate voltage and collector-emitter voltage, IGBT condition monitoring can be realized with a small short-circuit current. Considering the influence of junction temperature on short-circuit current, a junction temperature monitoring circuit is designed to ensure that the temperature is basically consistent during condition monitoring. Finally, the IGBT bond wire damage experiment is carried out by using the IGBT condition monitoring drive circuit, which verifies the feasibility of the proposed method.

Compared with the conducting and blocking steady-state processes, the voltage and current stress of IGBT become very higher in the turning-on and turning-off transient processes, and the instantaneous power loss increases significantly. The switching transient conditions greatly affect the reliability and stability of IGBT device and power converter. During the IGBT turning on process, the reverse recovery of the symmetrical bridge arm anti paralleled diode can cause additional turn-on loss and current peak overshoot. The gate voltage active control technology can effectively suppress current spike and reduce turn-on loss in the period from the initial opening time to Miller platform. The multilevel synthesis technology can adjust the gate voltage waveform and produce depression or bulge in the normal driving voltage waveform for a certain time. In this paper, the sensitive parameters of gate voltage active control, which affect the current overshoot, and turn-on loss of IGBT are studied based on the theoretical calculation and mathematical model. A multi-level synthesis gate voltage active control technology is proposed according to the principle of gate voltage active control. The relationship among the acting voltage amplitude, execution time, current peak and switching loss is studied. Considering the actual application conditions, the optimized active control scheme of gate voltage is designed. Finally, the switching characteristics test is carried out, the results verify that the proposed control technology can effectively reduce the current overshoot and turn-on loss in comparison with the conventional schemes.

In high voltage and high capacity applications such as offshore wind power, high-speed trains, direct current transmission, and ship-integrated power supply, insulated gate bipolar transistor (IGBT) is the core component of power conversion equipment. Its gate drive circuits are critical to improving switching performance, reliability, and efficiency. Compared with medium and low power drive circuits, the high power IGBT driver has the characteristics of higher isolating voltage, large driving power, large switching spike stress, and comprehensive fault detection and protection. In this article, the driver technology of 3.3 kV–6.5 kV voltage level IGBT modules is investigated and analyzed, such as the power supply of the drive circuit, the electrical isolation of the drive circuit, the overshoot suppression of the switch, and the short-circuit detection protection and the driving protection technical characteristics of the high-voltage and high-power IGBT are summarized. Then, the driver-level IGBT condition monitoring technology that focuses on the working state of the single module is discussed, and the development direction of the monitoring technology is prospected. Finally, some suggestions are put forward for the research direction of high voltage and high capacity IGBT drive technology, and more useful and practical solutions are provided for the design of high-voltage and high-power IGBT drive circuits.

Insulated gate bipolar transistors (IGBT) short‐circuit (SC) protection is one of the most important protection methods for IGBT converter equipment. The fast detection and protection response time could reduce the permanent damage of devices, and extend their use life cycle. At present, the collector emitter voltage v _ce desaturation method is widely used in the commercial IGBT drive circuit, which has blanking time of fault detection and protection. In this paper, an improved adaptive v _ce SC detection and protection is proposed to realize the blanking time adjustment under different SC conditions. By the determination of the d i /d t characteristics of the current variation on the parasitic inductance between the power emitter and the Kelvin emitter of IGBT modules, the execution time of the two detection methods can be set. According to the switch process and the SC type, the corresponding logic processing will be carried out to realize the fast detection of different SC conditions. The circuit scheme without blanking time detection and protection is designed, and the circuit is modelled and simulated by Pspice. The IGBT driving circuit SC test without blanking time detection and soft turn‐off protection has been carried out. Simulation and test results can verify the feasibility of the proposed circuit.

The bonding wires and busbars in IGBT modules may have open points and breaks during long-term use, causing changes in short-circuit current. The health status of the IGBT module can be analyzed by detecting and judging the short-circuit current. The self-excited short circuit monitoring technology controls the gate voltage to cause small current short circuits in the IGBT. By detecting the magnitude of the self-excited short circuit current, the damage to the IGBT module bonding wire is determined. The accuracy of the monitoring results of this method is affected by changes in device junction temperature. Based on the application scenario of urban rail traction inverters, this article proposes an improved temperature criterion for the self-excited short-circuit monitoring method. The multidimensional relationship between IGBT module short circuit current, health level, and temperature changes is analyzed. The temperature ranges for self-excited short circuit detection based on the actual operating conditions of urban rail inverter is studied, and the driving module status judgment is set to only determine the health status of effective data points within the temperature range. This method can suppress the influence of IGBT working temperature on short-circuit condition detection and improve the accuracy of the criterion. At last, a current detection experiment was conducted to simulate the fracture of bonding wires, verifying the effectiveness of the proposed method.