FPGA-based voltage control with PDM inverter for wideband drive system using T-type neutral-point-clamped topology

This paper shows a hardware design of pulse-density-modulation (PDM) inverter for wide band drive system. Broadband drive is one of the requirements for high speed motor drive. Linear power amplifier meets such requirement but also provides large energy consumption. In the paper, a class-D amplifier (switching amplifier) are designed and a broadband voltage control is conducted with FPGA-based PDM. FPGA realizes high speed switching and attains a high over sampling rate. This feature improves PDM performance and signal-to-noise rate (SNR). Furthermore, multi-leveling of inverter topology provides a synergistic enhancement. The paper shows analyses for PDM inverter and designs three level T-type neutral-point-clamped (NPC) inverter. Prototype inverter is shown and a performance validation of designed system is conducted.