Optimization of Boundary Current Mode Control Strategy for Reducing Zero-crossing Distortion in a H-bridge Inverter

The tendency of the inverter is high-efficiency, high-power density, and low THD. Soft-switching technology reduces the power loss of switches and improves the efficiency of the inverter. Soft-switching is realized in the inverter under boundary current mode (BCM) control. In the traditional unipolar BCM strategy, distortion is caused at the zero-crossing point, which is complicated to implement. Sine hysteresis current mode (SHCM) is used in this paper. SHCM is easy to be realized by software. The power loss of switches and the THD of the SHCM inverter have been analyzed by LTspice. The THD of the inverter operated in SHCM is better than that in constant critical current mode (CBCM). SHCM balances the THD and efficiency. The calculation of software is more simplified. SHCM inverter experiments testify that the SHCM inverter is more efficient than the continuous current mode (CCM) high-frequency inverter realized by software.