A Single-Phase Low Frequency Ac Transmission Method

This paper presents a single-phase low frequency AC transmission method for power cable transmission based on modular multilevel matrix converter (M3C-SLFAC). The SLFAC needs only two power cables as HVDC, and possess merits as lower charging current and power losses, larger transmissible capacity and transmission distance compared with HVAC. The SLFAC can also solve the problems in HVDC as space charge accumulation in power cable and the DC circuit breaker. In this paper, a quasi-square waveform is proposed as the voltage waveform of low frequency side to reduce the power ripple and to eliminate the voltage and current surge of transmission cable in low frequency side. Power balance strategy is proposed to keep power balance between power frequency side and low frequency side and to prevent the power ripple of the low frequency side from affecting power-frequency side. The comprehensive control strategy is proposed based on power analysis of M3C. The simulation results verify the effectiveness of the proposed method in PSCAD/EMTDC.