Hybrid-Frequency Modulation for PWM-Integrated Resonant Converters

• Published in: IEEE transactions on power electronics Vol. 28; no. 2; pp. 985 - 994
• Main Authors: York, B., Wensong Yu, Jih-Sheng Lai
• Format: Journal Article
• Language: English
• Published: New York, NY IEEE 01.02.2013; Institute of Electrical and Electronics Engineers; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Applied sciences; Circuit properties; Convertors; DC-DC modulation; Electric currents; Electric, optical and optoelectronic circuits; Electrical engineering. Electrical power engineering; Electrical machines; Electronic circuits; Electronics; Exact sciences and technology; Frequency modulation; Inductors; integrated boost resonant (IBR) converter; Power electronics, power supplies; Power supply; Prototypes; Pulse width modulation; Regulation and control; Signal convertors; Switches; Switching frequency; Transformers; Zero current switching; Electric transformer; State feedback; Power converter; Voltage dependence; Frequency modulation; PWM power convertors; Control circuit; Up converter; Diode; Conversion rate; Hybrid control; Resonant circuit; Power electronics; DC―DC modulation; Zero current switching; Frequency control; Switching loss; High efficiency; Electric loss; Resonant power convertors; Feedforward; Pulse duration modulation; integrated boost resonant (IBR) converter; On off effect
• ISSN: 0885-8993; 1941-0107
• DOI: 10.1109/TPEL.2012.2201960

This paper presents a unique modulation method for extending the input range of pulse-width modulation (PWM)-integrated resonant converters, such as the isolated boost resonant converter, while maintaining high conversion efficiency. The technique includes primarily the hybridizing of constant-on, constant-off, and fixed-frequency control depending only on the required duty cycle. The modulation scheme reduces core loss and conduction loss dramatically by decreasing the applied volt-seconds at the transformer and improving the switching period utilization. With hybrid-frequency control, the circuit also maintains zero current switching for the output diodes, minimizes switching loss, and eliminates circulating energy at the transformer across the entire operating range. It also allows for a predictable voltage gain, dependent only on duty cycle and transformer turns ratio. A detailed loss analysis is provided and verified against a 180 W experimental prototype, with an input range of 12-48 V and a switching frequency range of 30-70 kHz. Implementation issues are also handled with a variety of solutions for realizing the modulation scheme. Experimental results show greater than 4% weighted efficiency improvement in the prototype using the proposed method.