Fast and Reliable Geometric-Based Controller for Three-Phase PWM Rectifiers

Three-Phase Pulse Width Modulated (PWM) converters are used in a large number of applications, such as motor drives, energy storage systems, and wind turbines, among many others. Usually, the control of this type of converter is achieved by dual-loop control structures (inner-current and outer-voltage) implemented with linear-based compensators. As a consequence, the transient response performance of the closed-loop system is limited by the dynamics of the linear compensators, leading to sluggish transient responses. In this paper, a novel geometric-based control approach for the three-phase PWM rectifier is introduced in order to improve the converter dynamics under large transients. A geometric-large signal model of the converter that describes the average natural trajectories for the operating point under different conditions is derived. Based on the natural trajectories of the converter, a closed-loop geometric based controller that computes the path that the operating point must follow to achieve the target point is developed. As a result, during transients, the operating point is able to follow a well-determined trajectory. The characteristic features of the proposed method are fast, reliable and predictable transient responses, as well as low computational cost and low-bandwidth sensing and signal conditioning stages due to the average nature of the model. Simulation and experimental results of the proposed model and control technique are provided to validate the theoretical analysis and implementation of the geometric-based large-signal controller.