A Design Procedure for Optimizing the LLC Resonant Converter as a Wide Output Range Voltage Source

• Published in: IEEE transactions on power electronics 2012-08, Vol.27 (8), p.3749-3763
• Main Authors: Beiranvand, Reza, Rashidian, Bizhan, Zolghadri, Mohammad Reza, Alavi, Seyed Mohammad Hossein
• Format: Article
• Language: English
• Subjects: Applied sciences; Circuit properties; Dielectric, amorphous and glass solid devices; Electric currents; Electric, optical and optoelectronic circuits; Electrical engineering. Electrical power engineering; Electronic circuits; Electronic equipment and fabrication. Passive components, printed wiring boards, connectics; Electronics; Energy efficiency; Exact sciences and technology; Frequency conversion; Harmonic analysis; Impedance; LLC resonant converter; Power electronics, power supplies; Power supply; Prototypes; Resonant frequency; Semiconductor electronics. Microelectronics. Optoelectronics. Solid state devices; Signal convertors; switched-mode power supply (SMPS); Switching frequency; Voltage control; wide output range; zero current switching (ZCS); Zero voltage switching; zero voltage switching (ZVS)
• ISSN: 0885-8993; 1941-0107
• DOI: 10.1109/TPEL.2012.2187801

LLC resonant converter is one of the most suitable circuit topologies that have been introduced for designing constant output voltage switched-mode power supplies. In this paper, a design procedure is introduced for using this converter as a wide output range voltage source. Unlike constant output voltage applications which need small converter inductance ratio and narrow switching frequency variations, for wide output range applications, large values of these parameters are needed simultaneously and should be optimized. Instead of minimizing the components stresses, leading to a great value of the inductance ratio, proper choice of the converter parameters resulting in a smaller inductance ratio has been done. Maximum value of the capacitor in parallel with the power MOSFETs drain-sources has been derived to realize the zero voltage switching operation in the converter inductive region. Soft switching is achieved for all power devices under all operating conditions. A prototype of the converter has been tested for different regulated output voltages (35-165 V dc ) under different loads (0-3 A dc ) and input voltages (320-370 V dc ) for using an ion implanter arc power supply, with maximum efficiency value of 94.7%. Experimental results confirm the high performance of the wide output range LLC resonant converter even under the worst case conditions.