A high step-up DC-DC converter with active switched LC-network is proposed in this paper, which can be used in the photovoltaic (PV) system as the front-end stage to generate the required dc bus voltage. Based on the transformerless DC-DC converter with an active switched inductor (ASL) network, this proposed converter introduces an active switched capacitor (ASC) network, only one capacitor and one diode are added, while the voltage gain is efficiently increased by a compound of ASL and ASC network. The structure of the proposed converter is simple and voltage stresses on the additional diode and capacitor are low. In addition, unlike other voltage-boosting structures that utilized switched capacitor, the proposed converter avoids the extreme instantaneous currents of capacitor. The detailed analysis of the proposed converter and performance comparison with recently published ASL network-based converters are presented. Finally, a 100 W, 20/200 V prototype circuit is operated to verify its performance.

This paper proposes a new topology for an enhanced-boost quasi-Z-source inverter with an active switched Z-network. Compared to enhanced-boost quasi-Z-source inverters (EB-QZSI) with two switched impedance networks, this proposed inverter has the same high boost factor while using two fewer LC pairs and one fewer diode and only adds one switching device. In addition, current stress across switches is reduced by half, which leads to significant reduction in the conduction loss of switches and improves efficiency of the overall inverter. Moreover, the proposed inverter also draws continuous input current and maintains common ground between the source and the inverter bridge. Operation principles and comparisons with EB-QZSI are presented. Both simulation and experimental results validate theoretical analysis of the proposed inverter.