Research on On-line Monitoring Technology of Aluminum Electrolytic Capacitor in AC Power Supply

As one of the important power devices to guarantee the stability of AC power supply, the failure rate of aluminum electrolytic capacitor in AC power supply is as high as 60%. Therefore, in view of the problems that aluminum electrolytic capacitor in AC power supply is easy to fail and on-line monitoring is difficult, the on-line monitoring method of DC-Link capacitor in high-power AC power supply is studied. In this paper, the equivalent series resistance (ESR) was selected as the characteristic parameter of the degradation failure of aluminum electrolytic capacitor, and then the online monitoring method of the current state ESR value of aluminum electrolytic capacitor in operation was studied. Then, an online ESR monitoring model is designed to study the loss power of aluminum electrolytic capacitor. Through real-time monitoring of the ripple voltage and ripple current of the busbar capacitance, the ESR value of the current state is obtained. Finally, simulation and online monitoring experiments are used to verify the effectiveness of the scheme, and the relative error of monitoring results is less than 1%, and good monitoring effect is obtained.