A current mode control for a single phase full bridge Power Factor Compensator

Abstract

In this paper is presented a model based current controller for a Single Phase Power Factor Compensator (PFC). The proposed controller is based a description of the average model of the system. This control scheme is designed in two loops, namely the inner control loop or current loop and the outer loop or voltage loop. The first loop is aimed at compensating reactive power and current harmonic distortion in a single phase system, i.e. at guaranteeing a power factor close to unity. An adaptation scheme is introduced to cope with harmonic uncertainties in the system signals and system parameters. Additionally, an estimate of the series resistance is proposed to cope with the series resistor of the filter. The adaptation schemes proposed in the control law are reduced to a bank of resonant filters. These filters are tuned at the frequencies of the harmonics under compensation, which provides precise selective harmonic compensation. The second loop is designed to regulate the voltage load and it consists of a well known Integral plus Proportional controller (PI). Given that the output of the PI controller is a modulating signal which is used to construct the current reference, it has to include a Low Pass Filter (LPF) to restrict the bandwidth of the controller and avoid the harmonic pollution in a current reference which is produced by the rectification process. The topology selected for the PFC consists of a single phase full-bridge Voltage Source Inverter (VSI). The proposed control scheme and the power converter has been simulated and the results are presented here.