Step-up AC Voltage Regulators with High-Frequency Link

A circuit configuration and a circuit topological family of step-up ac voltage regulators with high-frequency link are proposed. This kind of circuit topology is composed of input LC filter, energy-storage inductor, input cycloconverter, high-frequency transformer, output cycloconverter and output filtering capacitor. The regulators can convert an unstable sinusoidal voltage with high THD to a stable sinusoidal voltage with the same frequency and low distortion. Operating principle, normalized output characteristics, phase-shifting control strategy, methods to suppress magnetic saturation of the energy-storage inductor at start-up, and voltage spike caused by the high-frequency HF transformer leakage inductance are proposed and fully investigated. The results from theoretical analysis and principle experiment indicate that the proposed regulators have advantages of high-frequency galvanic isolation, simple topology, two-stage power conversions, bidirectional power flow, high conversion efficiency, and high reliability during short-circuit conditions of the load.