改进型ZCT-PWM软斩波器的应用研究

Application research on an Improved ZCT-PWM Chopper

传统的斩波调功式感应加热电源大多采用的是硬斩波方式,开关器件的损耗很大,从而限制了系统容量和频率的提高。介绍一种改进型零电流转换-脉宽调制(ZCT-PWM)直流软斩波器,该软斩波器克服了传统ZCT-PWM中主开关器件不能零电流开通(ZCS)和负载续流二极管不能软关断的缺点,适合以IGBT为开关器件的大容量高频PWM变换器。对该变换器的稳定运行情况进行了详细的分析,并用PSpice9．0软件进行仿真验证,仿真结果表明该ZCT-PWM软斩波器的IG- BT开关频率可以达到100KHz,并实现较大范围的电压和功率调节,非常适合大容量高频感应加热电源场合。

It is difficult to improve the power capacity and frequency of the conventional induction heating power due to the losses made by the hard switching state of the power switches. In this paper, an improved ZCT - PWM （Zero Current Transition -Pulse Width Modulated） DC -DC chopper is proposed. The novel chopper can overcome most of the drawbacks of the conventional ZCT - PWM chopper, in which the main switching element does not turned on in soft switching state of Zero Current Switching （ZCS）, and the main diode turnes off in hard switching state. It is especially suitable for an insulated gate bipolar transistor （IGBT） PWM converter at high power capacity and frequency levels. A detailed steady state analysis and a PSpiee 9.0 simulator are used to show that the ZCT - PWM chopper can realize considerably large scale of regulation of output voltage and power at 100KHz of the switching frequency and the soft chopper is very suitable for application in induction heating power.