Design and simulation of feedback system to generate plasma arc in current source mode

Abstract

Plasma arc has drooping characteristics that means that the voltage drops suddenly with an abrupt rise of arc current. In short circuit mode, the load voltage becomes zero while drawing very high load current. This condition restricts the voltage source supply application in generation of plasma arc. The current source supply controls the load current irrespective of the load impedance. In this work, the load current is fed back to the compensator that is particularly designed for plasma arc load conditions and that controls the duty cycle of the full bridge inverter section for controlling the arc current at set value. This is used in conjunction with Switch Model Power Supply (SMPS) topology that reduces the cost and size of the system significantly. With this topology, even the short circuited load can be handled with load current held constant at set value. This type of plasma arc is very useful in various applications such as waste management, heating, high heat flux generation etc. A detailed analysis and simulation of the feedback system is described and the results are presented in this paper.