Flying Capacitor Resonant Pole Inverter with Direct Inductor Current Feedback

Abstract

Industrial applications, e.g. semiconductor manufacturing equipment, require power amplifiers providing 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 applied charge-based modulation scheme to ensure ZVS depends heavily on the correct measuring 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 introduced distortion of the output current. Simulation results of the complete converter and control configuration indicate a significant improvement in performance: 9 dB increased Spurious Free Dynamic Range (SFDR) and 16 dB decreased Total Harmonic Distortion (THD).