Overview of Multilevel Inverter Topologies and Modulation Methods.- NP voltage control strategy based on 6th harmonic injection for three-level converter.- Research on IGBT Condition Monitoring Based on On-state Voltage Drop.- Hysteresis Optimization and Power Converter Research of Direct Instantaneous Torque Control for SRM.- Simulation strategy of capacitor voltage fluctuation for railway power conditioner based on MMC-RPC topology.- Research on Hydrogen Power Station Accessing to Traction Power Supply System.