Single-stage buck–boost inverter with feedforward control

Abstract

The off-grid inverter with the inverter side voltage as the feedback parameter has the advantages of a single voltage loop, simple control parameter design, and low cost. But the output voltage accuracy is not enough. A single-stage off-grid inverter with feedforward control is recommended to improve the output voltage accuracy. It has a higher voltage regulation rate compared to the proportional–integral (PI) control and it can track a given AC signal at any frequency compared to the proportional-resonant (PR) control. Bus capacitors can employ thin-film capacitors for improved reliability and higher power density and the voltage stress on power devices can be decreased by controlling the intermediate bus voltage to a non-constant value. The working principle is explained. The design principles of the parameters are provided and the external characteristics and stability of the system are analyzed. A simulation model was built to verify the control strategy for improving voltage accuracy and decreasing voltage stress.

Keywords

• Voltage accuracy
• Off-grid
• Feedforward control
• Single-stage