Flying capacitor resonant pole inverter with direct inductor current feedback

Abstract

Industrial applications, such as semiconductor manufacturing equipment, require power amplifiers that provide high power with high precision and bandwidth. The Flying Capacitor Resonant Pole Inverter (FC RPI) provides a multilevel configuration with high switching frequencies and Zero-Voltage Switching (ZVS) across the entire operating range. However, the charge-based modulation scheme that is applied to ensure ZVS depends heavily on correct measurement of the zero-crossings of the filter inductor current. The delay incorporated in the measurement chain results in significant distortion of the output current, which deteriorates the performance of the end application. This research proposes to apply direct current feedback of the per-period average filter inductor current, measured using a high bandwidth Anisotropic Magneto-Resistive (AMR) sensor, to correct the distortion introduced in the output current. The simulation results of the complete converter and control configuration indicate a significant improvement in performance: 9 dB increase in Spurious Free Dynamic Range (SFDR) and 16 dB decrease in Total Harmonic Distortion (THD).