A phase synchronization control scheme for LCL-T type high-frequency current source in parallel connection

Considering the applications of high voltage gate driving system and contactless power transmission, a current-based power distribution is adopted as a kind of replacement of voltage based high-frequency Alternating Current (AC) power distribution system. In order to implement high-frequency current source, an LCL-T resonant inverter is examined with constant current characteristic and high conversion efficiency. First, the resonant topology is studied as a high-frequency power source, including circuit principle, operational cycle analysis, and AC analysis. The effective control and high conversion efficiency are both achieved by LCL-T resonant inverter. Second, the phase angle control scheme is explored to improve the synchronization performance in parallel system formed by multiple of LCL-T resonant inverters. Lastly, a prototype of parallel system is evaluated by simulation and experiment results, both of which are constructed by two resonant inverters with rated peak current of 2 A, rated output frequency of 30 kHz, and rated output power of 100 W. The experimental results in accordance with simulation prove that the better phase synchronization of output currents is achieved by the phase angle control. Hence, the high-frequency resonant topology and phase control scheme are a feasible realization of current source that can be used to feed current-based high-frequency power distribution system.