Robust Direct Current Control of Single-Phase PWM Rectifiers Based on a Mixed H2/H∞ Controller

: Robustness for single-phase pulse-width modulation (PWM) rectifiers which are employed for electric locomotives is essential since a train works in a dynamic environment where faults such as parameter perturbations and measurement errors often occur. These faults may lead to a subsequent failure and damage of costly components; thus, robust control is highly recommended. Apart from the robustness of a rectifier, its dynamic performance should also be considered. This paper presents the implementation of a direct current control (DCC)-based mixed H 2 /H ∞ controller for single-phase PWM rectifiers with the purpose of achieving robustness and a decent dynamic response in the presence of inductance variation, where settling time and percentage overshoot can be addressed by means of the pole placement method. In addition, the v-gap metric has been used as a tool for estimating robust stability. The proposed controller is compared with the direct current control-based H ∞ mixed sensitivity controller (DCC-H ∞ MS controller). The experiment results demonstrate that the proposed controller has a good dynamic performance against parametric uncertainties.