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

Inaccurate capacitance significantly increases the DC-Link rip-ple voltage of active power decoupling circuit (APDC). To solve this prob-lem, a high-precision online capacitance estimation method is proposed. This method converts the AC components of decoupling capacitor into the sum of DC component and AC component with 8 times grid frequency, which is beneficial to the extraction of DC component. This DC component replaces the AC component to effectively eliminate the periodic capacitance mutation, and accurately estimate the capacitance. Based on the capaci-tance, the DC-Link ripple is controlled with the set scope. Experimental results verify the effectiveness of the proposed method.