Design of Intrinsically Safe Soft Switching Buck Converter: A Two Time Scale Method

Decreasing the output inductance and capacitance of Buck converter is an efficient way to improve the intrinsic safety of switching power supply working under flammable and explosive conditions. However, the output voltage ripple (OVR) will become large for small output inductor and capacitor. To reduce OVR, the switching frequency of Buck converter needs to be highly increased. Thus causes problems such as high switching losses and high electro magnetic interference (EMI). ZVS PWM Buck converter, which works in soft switching ZVS PWM Buck ng mode, can effectively reduce the switching losses and EMI. This paper investigates the design of converter to meet both the intrinsic safety and OVR requirements. Method based on the two time scale system theory is proposed in this paper to design intrinsically safe ZVS PWM Buck converter for the purpose of intrinsic safety and low switching energy cost. The simulation experiments show the effectiveness of design. The method proposed in this paper can be used in the design of intrinsically safe switching power supply.