Investigation of Paralleled Inverters With Various-Order LC Resonant Tanks for Possible Surface Treatment Applications

This paper presents an investigation of paralleled inverters with LC, LCC, and LCLC resonant tanks (RTs) to generate plasma sources for possible material surface treatment. Based on the aspects of sensitivity, gain plots, simulation results, and output current total harmonic distortion (THD), the configurations of an LC, LCC, LCLC-A, and
$LCLC-D^{\prime} $
RTs are discussed. The inverters with the three types of RTs and with the phase shift and phase-difference controls are addressed. Unified phase shift and phase difference controls are adopted to achieve identical output currents. Simulated results of two and three module inverter systems with modular discrepancy have demonstrated the analyses and discussions. Hardware measurements of two (10kW) and three (15kW) inverter systems have been also presented to further verify the theoretical analyses and the control schemes. The measured efficiency of the prototype reaches 94% and THD is 1.52%. The significant contributions of this paper are the comparison of the three types of RTs and the selection of the most suitable RT for the application.