Active cancellation of capacitor ESR and ESL effects for improving converter transient and steady-state response

Abstract

An active cancellator that can reduce the capacitor equivalent series resistance (ESR) and equivalent series inductance (ESL) effects and provide capacitor current information is presented. The concept is based on connecting a linear voltage source in series with the capacitor to counteract the voltage drops caused by the ESR and ESL. Due to a reduction in the effective ESR and ESL, the damped resonant frequency of the "modified" capacitor is increased. The performance of the cancellator has been evaluated on an aluminum electrolytic capacitor. The effective values of the ESR and ESL are reduced by 1850 and 6.5 times, respectively, with the cancellator. The "modified" capacitor has been applied to a practical buck regulator. The capacitor current information provided by the cancellator is used to give an extra phase boost in the feedback loop of the regulator. Experimental results show that the proposed technique can help reduce the duration of ESL spike and magnitude of the ESR step appeared in the load transient, and steady-state output voltage ripple.

An Investigation of Size‐Reduction Effects in High Power Density Boost Converters with a Magnetic Coupling

“…Since actual capacitors involve the ESR as shown in Fig. 10 [20][21][22], the effect of ESR on current ripple need to be taken into account. Voltage drop due to ESR can be expressed with Δi c according to Ohm's law:…”

Impact of active resistance on dynamic power responses in a CERTS microgrid

“…The purpose of this paper is to present the concept of active resistance as a control technique for improving the steadystate and dynamic response of microgrids based on frequency droop-based power balancing controllers. Active resistance, or artificial resistance, is a control technique that has been successfully applied in other power electronics applications ranging from motor drives [4] to dc-to-dc converters [5]. Active modification of line impedance has been introduced in the context of inverter controllers for networks with low X/R ratios to correct for power and reactive power cross-coupling [3].…”

Efficient method to investigate the equivalent series resistance of a capacitor in low frequency range

“…The ESR leads to energy loss and causes a voltage ripple owing to the time-varying current, which deteriorates the performance of the capacitor. Moreover, the increased temperature caused by the large current resulting from the ESR will reduce the service life of the capacitor and affect the reliability of the electric circuit [4][5][6]. Thus, the ESR of a capacitor is an important performance parameter.…”