Analysis of a series-resonant converter with ZVS–PWM control

✍ Scribed by Hidekazu Tanaka; Takashi Yamane; Tamotsu Ninomiya; Masahito Shoyama; Toshiyuki Zaitsu

• Publisher: John Wiley and Sons
• Year: 2000
• Tongue: English
• Weight: 220 KB
• Volume: 83
• Category: Article
• ISSN: 8756-663X
• DOI: 10.1002/(sici)1520-6432(200001)83:1<59::aid-ecjb8>3.0.co;2-y

✦ Synopsis

Many resonant converters have been proposed previously, and their soft-switching techniques have yielded prominent features of high efficiency and low noise. However, the variable-frequency control is normally used to control the output voltage, and it results in a few problems such as the lowest switching frequency limiting the size reduction of the output filter and noise filter, and the beat phenomenon. In order to eliminate these limitations, we had previously proposed a novel ZVSPWM controlled current-mode resonant converter with an active-clamp circuit.

The purpose of this paper is to clarify the steady-state characteristics of this converter. First, the steady-state characteristics are analyzed, and then an analytical expression for the output voltage is derived through the concept of an equivalent ac resistance. Second, the zero-voltage-switching (ZVS) region is clarified. Finally, these analytical results are confirmed by experiment. Thus, it is possible to realize both ZVS operation and PWM control at a constant switching frequency.