Voltage-sharing of series connected IGBTs based on active voltage control and passive RCD technique

Owing to its limited voltage withstanding capability, a single insulated gate bipolar transistor (IGBT) cannot meet the requirements of high-voltage and high-power applications, such as energy saving and power quality improvement, flexible HVDC , high-voltage frequency converter, static synchronous compensator (STATCOM), active power filter(APF), and so on. For these applications, series connected IGBTs are a good solution, but a series of comprehensive issues need to be addressed. A comprehensive solution to the voltage-sharing of series connected IGBTs is proposed with respect to the gate driving module, referenced voltage waveform, over-current protection module, insulated power supply to gate driving unit and so on, and by combining the two techniques of active voltage control (AVC) and passive resistance-capacitor- diode (RCD) voltage-sharing. On this basis, a valve arm of four series connected IGBTs is developed, and the pulse test is done. The voltage-sharing of the four series connected IGBTs is stable during the pulse discharge test, and the voltage overshoot of each IGBT is suppressed to less than 5%. A prototype of three-phase voltage source converter (VSC) rated as 3 kV and 600 kVA is also developed, and rectifying as well as inverting operations at the rated power are stably carried out to verify the effectiveness and applicability of the series connected technique of the IGBT module. © 2013 State Grid Electric Power Research Institute Press.