On the basis of the classical Z-source inverter, this paper presents a developed impedance-type power inverter that is termed the switched inductor (SL) Z-source inverter. To enlarge voltage adjustability, the proposed inverter employs a unique SL impedance network to couple the main circuit and the power source. Compared with the classical Z-source inverter, the proposed inverter increases the voltage boost inversion ability significantly. Only a very short shoot-through zero state is required to obtain high voltage conversion ratios, which is beneficial for improving the output power quality of the main circuit. In addition, the voltage buck inversion ability is also provided in the proposed inverter for those applications that need low ac voltages. Similar to the classical Z-source inverter, the proposed concepts of SL Z-source inverter can be applied to various applications of dc-ac, ac-ac, dc-dc, and ac-dc power conversion. A detailed topology analysis and a generalized discussion are given. Both simulation and experimental results verify the analytical results.

Switched Inductor Z-Source Inverter

A new soft-switching dc/dc converter, which can solve the drawbacks of existing phase-shifted full-bridge converters such as narrow zero-voltage-switching (ZVS) range, large circulating current, large duty-cycle loss, and a large output filter in high-voltage applications, is proposed in this paper. The proposed converter is composed of two symmetric half-bridge inverters that are placed in parallel on the primary side and are driven in a phase-shifting manner to regulate the output voltage. At the rectifier stage, two full-bridge rectifiers sharing two low-current-rating diodes are employed. This structure allows the proposed converter to have the advantages of a full ZVS range, no problems related to duty-cycle loss, no circulating current, and a significantly reduced output filter. In this paper, the circuit configuration, operation principle, and relevant analysis results of the proposed converters are presented. Experimental results on a prototype converter realized with the specification of 80-in plasma display panel sustain power module (320-385 Vdc input, 205 Vdc/5 A output) validate the theoretical analysis.

Soft-Switching DC/DC Converter With a Full ZVS Range and Reduced Output Filter for High-Voltage Applications

A phase-shifted (PS) pulse-width-modulation (PWM) converter that can solve the drawbacks of existing PS full-bridge converters, such as narrow zero-voltage-switching (ZVS) range, large duty-cycle loss, large circulating current, and serious secondary-voltage overshoot and oscillation, is proposed in this paper. The proposed converter is composed of two symmetric half-bridge converters (TSHBCs) that are placed in parallel on the primary side and are driven in a phase-shifting manner. Their transformers are connected in series on the secondary side. At the output, a simple energy-recovery circuit (ERC) is employed. Due to this structure, the proposed converter has the advantages of wide ZVS range, less duty-cycle loss, reduced circulating current, and no secondary-voltage overshoot and oscillation, which results in the reduction of rectifier diodes' voltage stress and EMI. Therefore, the conversion efficiency is higher and the cost of the secondary rectifier is reduced compared to its PS PWM counterparts. In this paper, the circuit configuration, operation principle, and relevant analysis results of the proposed converters are presented. Experimental results on a prototype converter realized with an 80-in plasma display panel sustain power module (320-385 Vdc input, 205 Vdc/5 A output) validate the theoretical analysis.

Phase-Shifted PWM Converter With a Wide ZVS Range and Reduced Circulating Current

This paper presents a new single-stage single-switch (S4) high power factor correction (PFC) ac/dc converter suitable for low-power applications (?150 W) with a universal input voltage range (90-265 Vrms). The proposed topology integrates a buck-boost input current shaper with a quadratic buck converter. As a result, the proposed converter can operate with larger duty cycles compared to the exiting S4 topologies; hence, making them suitable for high-frequency nonisolated applications. Additional features are gained when both the input PFC buck-boost cell and the quadratic buck cell operate in discontinuous conduction mode (DCM). These features include low semiconductor voltage stress, zero-current switch at turn-on, and simple control with a fast well-regulated output voltage. A detailed circuit analysis is performed to derive the design equations. The feasibility of the converter is confirmed with results obtained from a computer simulation and an experimental prototype.

Integrated Buck–Boost–Quadratic Buck PFC Rectifier for Universal Input Applications

A multiple-output dc-dc converter with shared zero-current-switching (ZCS) lagging leg is presented in this paper. In this proposed converter, each output is regulated by the phase shifted between the independent leading legs and the shared lagging leg. The switches in the leading legs process the individual output power and work in zero-voltage switching (ZVS), which are suitable for utilizing the MOSFETs; the switches in the shared lagging leg process the total output power and work in ZCS, which especially suit for using the insulated gate bipolar transistor. The ZVS of the leading legs is easy to achieve and the ZCS of the lagging leg is independent of the loads. Therefore, the proposed converter has compact structure, fully regulation abilities, adapted soft-switching modes, and simple modulation schemes. Moreover, the new outputs can be conveniently obtained by using the uniform algorithm. In this paper, the derivation of the proposed converter is presented; the proposed shared ZCS lagging leg converter with dual output is analyzed, and the analysis is further extended to the general multiple-output situation; the state variation of the proposed converter is also surveyed; finally, a three-output prototype with 200-240 V input, 24 V/5 A, 15 V/15 A, and 12 V/10 A outputs is built, and the analysis is verified by the experimental results.

The Multiple-Output DC–DC Converter With Shared ZCS Lagging Leg

In this paper, an improved current-doubler rectifier with coupled inductors is proposed. The proposed rectifier can extend duty ratio to reduce the peak current through the isolation transformer winding and lower output current ripple as well as voltage stress of the rectifier diodes. In this study, a 500-W prototype with a full-bridge phase-shift converter, the proposed rectifier, with input voltage of 400 V and output voltage of 12 V was built. Theoretical analysis and experimental results have verified that the proposed rectifier is attractive for high step-down voltage and high-power applications.

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Y.-D. Chang

Papers

Analysis and Implementation of an Improved Current-Doubler Rectifier With Coupled Inductors