| Abstract |
This paper presents a new mathematical model and a PWM switching technique for a three-phase grid-tie bidirectional DC-AC converter. The converter topology is designed based on linking an H-bridge to a three-to-single-phase matrix converter through a single-phase high-frequency transformer. The proposed mathematical model uses the trapezoidal waveform approximation for the high-frequency current waveform in order to obtain the accurate duty cycles of all matrix converter switches. The system performance based on trapezoidal approximation is compared with square-wave approximation. Also, the proposed PWM switching technique regulates battery DC current and injects a sinusoidal three-phase current to grid at unity power factor. Therefore, the grid injected current has low total harmonic distortion (THD), and the system overall efficiency is high. The system validity has been verified experimentally using a 200 V/1.8 kW laboratory prototype. |
