Voltage Sag Ride-Through Capabilities of Electrolytic Capacitor-less Adjustable Speed Drive System During Power Interruptions

Due to thin film capacitor's enhanced reliability and improved input current harmonic performance, adjustable speed drives (ASDs) without using electrolytic dc-link capacitors have been researched extensively in recent years. However, because of thin film capacitor's smaller capacitance per volume, its voltage sag ride-through capabilities are called into question. In this paper, the maximum time duration for an electrolytic capacitor-less ASD system during a power blackout is quantified based on theoretical analysis. An effective voltage sag ride-through method which can achieve maximum hold-up time duration is presented. Experiments are further conducted on a 2.2kW, 380V, 50Hz ASD setup with thin film dc-link capacitor to validate the theoretical analysis.