Wide Voltage Resonant Converter Using a Variable Winding Turns Ratio

Abstract

This paper presents a inductor–inductor–capacitor (LLC) resonant converter with variable winding turns to achieve wide voltage operation (100–400 V) and realize soft switching operation over the entire load range. Resonant converters have been developed for consumer power units in computers, power servers, medical equipment, and adaptors due to the advantages of less switching loss and better circuit efficiency. The main disadvantages of the LLC resonant converter are narrow voltage range operation owing to wide switching frequency variation and limited voltage gain. For computer power supplies with hold-up time function, electric vehicle battery chargers, and for power conversion in solar panels, wide input voltage or wide output voltage operation capability is normally demanded for powered electronics. To meet these requirements, the variable winding turns are used in the presented circuit to achieve high- or low-voltage gain when Vin is at low- or high-voltage, respectively. Therefore, the wide voltage operation capability can be implemented in the presented resonant circuit. The variable winding turns are controlled by an alternating current (AC) power switch with two back-to-back metal-oxide-semiconductor field-effect transistors (MOSFETs). A 500-W prototype is implemented and test results are presented to confirm the converter performance.

Analysis and Verification of a Wide Input Voltage PWM Converter with Variable Windings

“…Lr1 at time t 1 is greater than the capacitor energy 2C oss V 2 in , then C Q2 can be discharged to zero voltage at time t…”

“…The maximum output voltage versus minimum output voltage of the solar panels may be greater than 4:1. Conventional DC converters with wide voltage operation [1][2][3][4][5][6][7] for wind and solar power conversion are based on the circuit topologies of series-parallel connection or multi-stage conversion. However, the multi-stage circuit structure will result in low circuit efficiency and reliability.…”

A Hybrid DC–DC Quadrupler Boost Converter for Photovoltaic Panels Integration into a DC Distribution System

“…Several high-voltage gain DC-DC step-up converters for renewable energy applications can be found in the literature [26][27][28][29][30][31][32]. In this section, the proposed converter is compared only to the converters that have shared ground between the input and the output, and do not have any floating active switch or coupled inductors.…”

Resonant Asymmetrical Half-Bridge Flyback Converter

“…Although the research in [1,2] provides the input voltage range with wide variation range of switching frequency, it also results in efficiency reduction and EMI problems. The multi-level approaches proposed in [3][4][5][6][7][8][9][10][11] make LLC converters extend the operating voltage range, but still have the problems of the number of components, complex structure, and difficult control, so as to make it difficult to balance cost and performance. Based on the reasons above, the flyback-based topologies are still attractive solutions.…”