Design of Energy Control Method for Three-Phase Buck-Type Rectifier With Very Demanding Load Steps to Achieve Smooth Input Currents

Conventional three-phase rectifiers are controlled to achieve good power factor and low total harmonic distortion 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 lifetime operation of the generator, especially when it is not oversized (as in the case of aircraft applications). In order to smooth the power demanded from the generator, it is preferable to reduce the bandwidth of the output voltage controller for the rectifier but it affects its stability due to the fact that the right-half-plane (RHP) 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 that utilizes the energy stored in the output capacitor of the rectifier to control the output voltage of the rectifier. In such a way, the minimum bandwidth restriction imposed by the RHP pole of the power load is eliminated and the bandwidth of the voltage loop can be defined low enough to demand smooth power from the generator.