Effects of parasitics on the control of voltage source inverters

Advancements in ac industrial drives have been propelled through improvements in power electronics and control hardware. Improvements in insulated gate bipolar transistors (IGBTs) allowed faster switching speeds, which provides lower thermal losses. Digital signal processors and improved control algorithms allow ac drives to address applications previously handled by dc drives. Capacitive coupling between the IGBT, power structure, and control platform components influence drive dynamics and contributes to signal and waveform distortion. This differential and common mode capacitance is often disregarded as 'parasitics' and not considered in designing the control. This paper decouples the major contributors to motor waveform distortion, analyzes them, quantifies them, and presents a correction strategy. Simulations validate the analysis and experimental results demonstrate the strategy's benefits. Index Terms--Capacitive coupling long cables, dead time compensation, IGBT, parasitics, power device drop, power device dynamics, voltage distribution.