Conventional switched boost inverters (SBIs) employ a single LC-pair in the impedance network to boost the input voltage by setting a shoot-through interval in the inverter bridge switches. This study extends the concept of SBIs to the transformer-based switched boost inverters (trans-SBIs). By changing the turn ratio of the transformer, the proposed trans-SBIs can produce a strong voltage gain. Compared with a tapped-inductor Z-source inverter with the same voltage gain at the same transformer turn ratio, the proposed trans-SBIs have only one extra active switch but significantly fewer passive components. Compared with trans-ZSI, the proposed trans-SBIs use a transformer with a lower turn ratio to achieve a higher boost factor. The required current rating of the switches in the proposed trans-SBI is lower than for the alternative ZSIs. The operating principles and the analyses and comparisons with the conventional transformer-based ZSIs are presented. To verify the high boost capability of the proposed inverters, a laboratory prototype was built for both the single-phase and three-phase trans-SBIs.

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Abstract:The maximum boost control method for a single-phase switched-boost inverter (SBI) and single-phase Z-source inverter (ZSI) is proposed in this paper. In the proposed method, the low frequency voltage is added to the constant voltage for generating the variable shoot-through time intervals. For improving the AC output quality of the inverter, an active power switch is used to replace one of the diodes in the single-phase SBI. The operating principles and circuit analysis using the proposed maximum boost control method for single-phase inverters are presented. Laboratory prototypes are built to verify the operation of the proposed pulse-width modulation (PWM) control method for both single-phase quasi-ZSI and single-phase quasi-SBI.

Abstract:A non-isolated high boost DC-DC converter topology based on a switched-capacitor (SC) structure is introduced in this paper. By controlling the duty cycle in each period, the voltage gain of the converter is adjusted. The main features of the proposed SC converter are the continuous input current, achieving high voltage gain with low voltage and current stress on the power components, no use of a high-frequency transformer, and easy to increase the voltage by adding the SC cell.

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