Application of hybrid system theory to switching control of a three-phase inverter

A novel discrete event based current controller for three-phase load driven by power inverter is proposed. Main design specifications are robustness to load electrical parameters, fast dynamic response, reduced switching frequency and simple hardware implementation. To meet previous specifications a switching two types of controllers are developed: hysteresis type and Lyapunov type. The voltage source inverter (VSI) is represented as event driven system with 2³ modes of operation. The switching among these modes is governed by the supervisory control approach. The overall stability of the system is shown using Lyapunov technique. The Lyapunov functions used contain a term penalizing incremental energy of control error, torque and stator currents, enhancing the stability. The regulation with the proposed control law provides good transient response of the brushless BLDC motor control. A new logical FPGA torque controller based on Lyapunov stability theory are developed, analyzed and experimentally verified.