Design of energy control method for three-phase buck-type rectifier with very demanding load steps

Abstract

Conventional three-phase rectifiers are controlled to achieve good power factor and low THD in the input. In the case of pulsating power loads, the fast dynamic response implies that the load pulses are reflected in the generator. These pulsating loads affect the life time operation of the generator, especially when it is not oversized (that is the case in aircraft applications). In order to smooth the power demanded from the generator, it is preferable to reduce the bandwidth of the controller to the rectifier but it affects its stability due to the fact that the right half plane pole given by the negative impedance of a constant power load requires high bandwidth control loop to compensate it. In this paper, an energy control method is proposed to employ the energy stored in the output capacitor of the rectifier to control the amount of power demanded through the rectifier. In such a way the bandwidth restriction for stability is eliminated and the bandwidth of the loop can be set slow enough to ensure smooth power demanded from the generator.