A Three-Level Converter with Output Voltage Control for High-Speed Railway Tractions

A modeling and quantitative controller design of a three-level pulse width modulation (PWM) converter with good input power factor correction for high-speed railway tractions is presented in this paper. First, a three-level converter with neutral-point voltage-balance control (NPVBC) is used to reduce the voltage stress of power switches, voltage harmonics, and electromagnetic interferences (EMI). The circuit operations and switching control strategies of the adopted three-level converter are described in detail. As to output voltage control, a feedback controller is designed to meet the given voltage regulation control specifications. Then, a robust voltage controller is proposed to improve the control performance when the parameter variations caused by system configuration change and operating point shift have occurred. Some simulation results are made to verify the effectiveness of the proposed controller.