A Multi-Harmonic Method for Real Time Capacitor Condition Monitoring in Adjustable Speed Drive Systems for Industry 4.0
Capacitor age monitoring is essential in power electronics since the age of the capacitor significantly affects the performance of the overall system. The life of a capacitor is measured using the ESR resistance associated with the capacitor. The capacitor needs to be replaced once the ESR resistor’s resistance doubles. Now typical Adjustable Speed Drives have capacitors in the DC link. Commonly ASD failures are attributed to wear and tear of the DC link capacitors. The proposed multi-harmonic method estimates the ESR resistance of the DC-link capacitor and its capacitance value using DC-link voltage and current measurements as obtained from the ASD. This implies that no additional sensors or signals are required for capacitor condition monitoring. This method has shown to be operational in both balanced and unbalanced voltage operating conditions and we envision its deployment as a cloud based algorithm to help monitor several ASD systems in an industrial setting leading to the Industry 4.0 standard.