High-Frequency Operation of a DC/AC/DC System for HVDC Applications

摘要: Voltage ratings for HVdc point-to-point connections are not standardized and tend to depend on the latest available cable technology. DC/DC conversion at HV is required interconnection of such schemes as well interface dc wind farms. Modular multilevel voltage source converters (VSCs), modular converter (MMC) or alternate arm (AAC), have been shown incur significantly lower switching losses than previous two- three-level VSCs. This paper presents a dc/ac/dc system using transformer coupling two In system, capacitors occupy large fraction volume cells but significant reduction in can be achieved by raising ac frequency. Using high frequency also bring benefits other passive components results higher due number waveform steps per second. leads tradeoff between which has explored this study verified simulation with transistor level model 30-MW case study. The outcome shows that 350 Hz provides improvement penalty compared 50 Hz.