Single‐phase small capacitor motor drive system with high‐efficiency buck active power decoupling converter

Abstract

This paper proposes a novel active power decoupling circuit (APDC) based on modified Buck converter to reduce the DC‐link voltage ripple of small capacitor motor drive systems. The APDC is placed between the Boost PFC circuit and the DC‐link, and has two energy flow paths, and the sum of the power decoupling capacitor and the DC‐link capacitor voltage equals to the output voltage of the Boost converter. With these configurations, the voltage of the decoupling capacitor can be precisely controlled to be the same as the AC component of the output voltage of the Boost converter, thereby effectively reducing the DC‐link voltage ripple. Another unique feature of the proposed APDC is that the inductor works in discontinuous current mode and only work for half of the time, which not only reduces the current stress of power switches, but also further improves the efficiency of the proposed APDC. Then, an instantaneous voltage control method is investigated to reduce the DC‐link voltage drop, which significantly improve the dynamic performance of the motor. The design guideline of key components is given in detail. The feasibility of the small capacitor motor drive system based on the proposed APDC is verified by experimental results.

An online capacitance estimation method based on DC component applied in PFC converter with split-capacitor

“…APDCs with small film capacitors can replace electrolytic capacitors, which extend the life of PFC converters [3,4,5,6]. Some control strategies are applied in the APDCs to suppress the ripple voltage on the DC-Link due to the significant reduction in decoupling capacitors.…”

Model Predictive Current Control for DC-Link Ripple Voltage Suppression in Electrolytic Capacitor-Less Drive System

“…However, there is a larger DC-link ripple voltage due to the significant reduction of the decoupling capacitor. This ripple voltage degrades the performance of ECL drive systems [9][10][11][12]. Therefore, it has become an interesting and challenging topic for APDCs to achieve small DC-link ripple voltage under various operation conditions.…”