Parameter Design of Multi-frequency Triple-port Modular Multilevel Converter

The rapid development of low frequency AC transmission system brings the power system a third frequency. A new multi-frequency triple-port modular multilevel converter is proposed to realize power conversion among the three systems. The equivalent circuit of the converter is analyzed. Number of submodules and modulation ratio is designed according to the equivalent circuit. The design method of branch inductance considers power constraint, output quality, circulating current resonance and fault current rising rate. Submodule capacitance is designed by voltage ripple on each capacitor.