Hosein Hayati - Department of electrical engineering Islamic azad university of ardabil Ardabil, Iran
Abbas Rahimi - Department of electrical engineering Islamic azad university of Ardabil Ardabil, Iran
Parastoo Khademi - Department of electrical engineering Islamic azad university of Ardabil Ardabil, Iran

Capacitor used in rectifier circuits and filtering capacitors are an essential part in a switch mode converter and power inverter, and play importance role in their reliabilityand quality. Electrolytic capacitors which are widely used in these converters have ESR and ESL. These elements increasevoltage ripple in output and cause resistive loss in capacitorand they are signs of decrement in longevity. This paper uses amethod in which a reference resistor is placed in series with a capacitor, and then a sinusoidal voltage is applied. Using complex impedance method ESR is estimated. Next using square wave form voltage and LMS estimation method capacitance is calculated. High accuracy of proposed method is proved by simulation results.

phase difference; equivalent series resistance (ESR); least mean square (LMS); complex impedance;equivalent series inductance (ESL)