Efficient voltage regulation of modified hybrid dc-dc converter

Abstract

Switch mode dc-dc converters are attractive for their small size, ease of control and efficient power conversion. Output voltage is regulated by duty cycle control of semiconductor switch of switch mode dc-dc converters. The voltage gain and efficiency of practical switching regulators deviate from ideal values at extreme duty cycles. Also, desired gain /attenuation is not achievable at high/low duty cycles. In applications where high gain or high attenuation of voltage is desired with acceptable energy conversion efficiency, hybrid dc-dc switching converters are used. Hybrid dcdc converters are combination of voltage multiplier/division circuit with appropriate SMPS circuits. By incorporating voltage multiplier/division cell with conventional converters like Buck, Boost, Buck-Boost, Cuk and SEPIC converters, desired voltage gain (either very low or very high) may be achieved at acceptable energy conversion efficiency. In the present work with an aim to attain very high voltage gain by conventional Boost, Buck-Boost, Cuk, and SEPIC topologies, a new voltage multiplier cell consisting of multiple inductors and diodes is proposed. The proposed voltage multiplier cell can be duplicated in multiple number and attached at the input side of Boost, Cuk, and SEPIC converters for hybrid operation to attain very high voltage gain at acceptable energy conversion efficiencies. In the present work, proposed multi-inductor voltage multiplier cell is attached to input side of Boost, Cuk, SEPIC and Buck-Boost converters and the performance of the resulting hybrid converters are studied generically by simulation. The performances of proposed hybrid converters have been compared with the performance of a previously reported two inductor voltage multiplier cell based hybrid dc-dc converters. The performance results were almost similar for both hybrid high gain dc-dc converters. However, it has been shown that the voltage gain can be further enhanced by more than two inductor cell voltage multiplier in the proposed circuits. The inductor numbers are limited to two in previously reported high gain hybrid dc-dc converter. Hence, the investigation of this research has come up with a new proposed multiplier, which when attached to the front end of dc-dc Boost, Cuk and SEPIC converters may provide very high voltage gain at acceptable energy conversion efficiency.