Using current-fed parallel-resonant inverters for electrodischarge applications: a case of study

In this paper the current-fed parallel-resonant inverter for low-medium power electrodischarge applications is investigated. The behavior of the inverter when operating with constant input current or variable input current is studied as a solution for controlling the output power by using switching frequency as control parameter. The goal of this study is to prove that cost can be reduced by avoiding the use of an additional input stage. The different commutation modes that take place when varying the switching frequency around resonance are also reviewed and analyzed. The effect of leakage inductance in commutations is also considered. As conclusion, the operation below resonance using an overvoltage snubber is preferred in order to increase efficiency. Finally, the application of the proposed converter to ozone generation systems is presented. Experimental results are also included in order to validate the theoretical study.