Verification tests of 3.3 kV SiC (Silicon Carbide) hybrid IGBT inverter for Nishi-Nippon Railroad Co., Ltd 3000 series

Compared to a Si (Silicon) power device, an SiC (Silicon Carbide) power device is regarded as an indispensable power device for realizing the next generation power converter, because of its low switching loss, higher speed, and capability to operate at high temperatures. Toshiba developed an SiC hybrid IGBT (Insulated gate type bipolar transistor) with a withstand voltage of 3.3 kV for 1,500 V DC catenary systems [1] [2]. This is applied to the traction inverter of Nishi-Nippon Railroad Co., Ltd.´s 3000 Series train cars. By utilizing the reduced switching loss characteristic of SiC hybrid IGBT, improvements in the inverter output current and carrier frequency of PWM control are now possible while retaining the performance of a conventional inverter cooler. With the purpose of conserving energy, this paper introduces the development and verification test results of the traction control focusing on: (1) Enhancing regenerative brake force in high speed region (2) Reducing motor harmonics loss by multi-pulsing of PWM control.