High-efficiency design and control of zeta inverter for single-phase grid-connected applications

The conventional zeta inverter has been used for single-phase grid-connected applications. However, it has high switching losses to operate at high switching frequency in the continuous conduction mode (CCM). To address this drawback, this paper suggests a high-efficiency zeta inverter using active clamp and synchronous rectification techniques. The proposed inverter utilizes the active clamp circuit for reducing switching losses. The non-complementary switching scheme is adopted for not only clamping the switch voltage stresses, but also alleviating the circulating energy. In addition, the synchronous rectification is implemented for reducing the body diode conduction of power switches. By using the silicon carbide (SiC) metal oxide semiconductor field effect transistors (MOSFETs), the switching performance of the proposed inverter is improved. Its operation principle and control strategy are presented. A 220-W prototype has been designed and tested to evaluate the performance of the proposed inverter.