High-Efficiency Design and Control of Zeta Inverter for Single-Phase Grid-Connected Applications

Abstract

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.

Bidirectional Operation Scheme of Grid-Tied Zeta Inverter for Energy Storage Systems

“…Up to now, various single-phase isolated grid-tied inverters have been developed with renewable energy sources [1][2][3][4][5][6][7][8][9][10]. Among them, the grid-tied zeta inverter has been recently developed for high-efficiency inverter designs [7][8][9][10]. It has been gaining high attention due to its circuit count reduction design [9,10].…”

“…Among them, the grid-tied zeta inverter has been recently developed for high-efficiency inverter designs [7][8][9][10]. It has been gaining high attention due to its circuit count reduction design [9,10]. As the state-of-the art techniques, the grid-tied flyback inverter [1][2][3] and the grid-tied Cuk inverter [4][5][6] necessarily use a bidirectional switch along with the unfolding switching circuit at the grid side.…”

“…It needs the additional gate driving circuit, which causes drawbacks for increasing the manufacturing cost and decreasing the power density for industrial uses. On the other hand, the grid-tied zeta inverter can solve the drawbacks of the current state-of-the art inverters because it does not use the bidirectional switch at the grid side [9,10]. It can reduce the circuit components and improve the power density.…”

Soft-Switching Bidirectional Three-Level DC–DC Converter with Simple Auxiliary Circuit

“…Aside from energy storage systems [4], the bidirectional three-level DC-DC converter has been utilized for ultra-capacitor applications [5] and various electric vehicle charging applications [6,7]. However, it still has switching power losses as it operates under a hard switching condition [8]. Particularly, in the case of using metal oxide semiconductor field effect transistors (MOSFETs), the turn-on switching losses are highly increased as the converter operates at high frequency and high output load condition [9].…”

“…In order to reduce switching power losses, the converter should operate under a soft switching condition [8]. The quasi-resonant switching technique can be adopted for reducing switching power losses [10][11][12][13].…”