Single‐stage buck‐boost off‐grid inverter with feedforward control

Summary Since the output voltage accuracy of the off‐grid inverter is low with the proportional‐integral (PI) control and a two‐stage inverter is often used in the low input voltage application, a single‐stage buck‐boost off‐grid inverter with feedforward control is proposed. The proposed inverter consists of a buck‐boost converter and a full‐bridge inverter. The buck‐boost converter operates at high frequency, while the full‐bridge inverter operates at line frequency. Therefore, the intermediate bus voltage is controlled as the unipolar half‐cycle sinusoidal voltage wave to reduce the voltage stress of semiconductors, and film capacitors can be used as intermediate bus capacitors for high reliability and high power density. The operating principle is illustrated. Design guidelines and example are given. The stability analysis and external characteristic analysis are given. A 500‐W proposed inverter is constructed to verify the theoretical analysis.