دانلود رایگان مقاله انگلیسی مدل سازی، تحلیل و پیاده سازی بارهای مقاومتی تغذیه مبدل فلای بک کم قدرت ولتاژ بالا - IEEE 2018

Abstract

In High Voltage Flyback converters, the dominant factor that influences a converter operation is the parasitic capacitance. A significant portion of input energy is utilised in charging the parasitic capacitances of the circuit, which is circulated back to the source at the end of every switching cycle. The circulating energy is a function of output voltage, load power and parasitic capacitances and remain significant in High Voltage Low Power (HVLP) applications. This energy transfer phenomena involving parasitic capacitances results in reduced fraction of input energy reaching the load in every cycle, thereby resulting in an apparent deviation in converter operating point compared to ideal flyback in case of resistive loads. An analytical energy based model is derived including the effect of parasitic capacitances, valid for steady state and dynamics of High Voltage Low Power (HVLP) flyback converters feeding resistive loads. The influence of parasitic capacitances on switch voltage of the converter is exploited to achieve Zero Voltage Switching (ZVS) thereby minimising the turn on loss. The proposed analytical model is verified through simulation and experimental results on 1.5 kV / 5 W and 1.5 kV / 200 mW resistive load.

VI. CONCLUSION

A dominant impact of parasitic capacitance is observed in a HVLP flyback converter. Implementing ideal flyback converter model ignores the parasitic capacitance effect hence underestimates the amount of input energy required to reach a desired output voltage. The circuit based mode equations of converter including the parasitic capacitance effect is presented and extended to steady state to derive the steady state voltage gain of a HVLP flyback converter feeding resistive loads. Circuit based equations demand a mathematically intensive procedure to determine the converter operating point. Hence, a simplified energy based model which provides better insight on the parasitic energy is proposed and an expression for steady state peak current required to achieve desired output voltage is derived. A modified dynamic model including the parasitic capacitances of the converter is derived to implement a compensator based control scheme for achieving steady state voltage regulation targeting low power resistive loads. The proposed analytical model is validated through simulation and experimental results. The simulation and experimental results obtained are in good agreement with analytical results.