An Integrated Single-Stage Buck–Boost Asymmetric Inverter Under Wide Input Voltage Range

This article proposes an integrated single-stage buck–boost asymmetric inverter, which improves the circuit performance to cope with input voltage fluctuating over a wide range under a compact design. The proposed inverter integrates a buck–boost converter and a full-bridge inverter, which can achieve higher voltage gain without adding extra switches and has lower switching voltage stress under step-down condition. In order to solve the problem of waveform distortion caused by overmodulation in existing hybrid modulation, a hybrid modulation scheme is proposed. The inverter takes switching frequency and duty cycle as control variables to realize hybrid modulation with greater freedom. Part of the switches works at low frequency to reduce the overall switching loss, while others operate at high frequency to suppress total harmonic distortion (THD). The topological configuration, operating principles, modulation, steady-state analysis, and performance comparison with other step-up inverters are presented. Finally, the theory is verified by a 200-W prototype.