A Quasi-Online Monitoring Method of Output Capacitor and Boost Inductor for DCM Boost Converter

As inductor and output capacitor are the key components of a power converter, it is very important to identify their electrical parameters. This paper proposes a non-invasive quasi-online monitoring method of output capacitor's equivalent series resistance (ESR) and boost inductance (L) for a boost converter working in discontinuous conduction mode (DCM). The calculation formulas for ESR and L are derived based on the ac component of the output voltage at a particular time and other circuit parameters. The pulse-width modulation (PWM) wave shaping circuit and the isolation and amplification circuit are designed to obtain the parameters required in calculation. The proposed method needs no current sensor and does not influence the regular work of the converter. A prototype is established in the lab and the experimental results demonstrate the feasibility of the proposed scheme.