Design and Analysis of a Conductance Compensator for Keeping Constant Bandwidth and Output Impedance in Average Current Mode Control

Abstract

Take the case of parallel modules in battery discharging regulator of power conditioning unit, which is based on Weinberg topology, a conductance compensator used in average current mode control is proposed in this paper, which could ensure constant loop bandwidth and output impedance when the number of operating parallel modules changes. The design principle of conductance compensator is shown as that the total conductance coefficient keeps constant when the number of operating parallel modules changes. Besides, a circuit of the conductance compensator, and the timing between the regulation of conductance compensator and ON/OFF of parallel modules, as well as the frequency-domain constraints of each function part in outer voltage control loop, are also illustrated. Additionally, measurements of the loop characteristic and output impedance of regulated power bus with different numbers of operating parallel modules, as well as the voltage ripple and current waveforms at the ON/OFF moment of parallel modules (four parallel modules in total), have been carried out, validating the design purpose of the proposed conductance compensator.