Closed loop control of excitation parameters for high speed switched-reluctance generators

Abstract

This paper presents a new approach to the automatic control of excitation parameters for the switched-reluctance generator (SRG) where the SRG system operates at sufficiently high speed that it operates in the single pulse mode. The turn-on and turn-off angles are the two parameters through which we can control the electric power generation. The objective of the work is to develop an easily implementable control algorithm that automatically maintains the most efficient excitation angles in producing the required amount of electric power. The work is focused on finding the most efficient excitation angles and characterizing them for easy implementation under closed loop control. Through modeling of an experimental SRG and extensive simulation, it can be seen that the optimal-efficiency turn-off angles can be characterized as a function of power and speed level. Within the closed-loop power controller, the optimal-efficiency turn-off angle is determined from an analytic curve fit. The turn-on angle is then used as the degree of freedom necessary to regulate the power produced by the SRG. Given that the turn-off angle is associated with optimal-efficiency at each speed and power point, overall operation is achieved at optimal-efficiency. The SRG, inverter and control system are modeled in Simulink to demonstrate the operation of the system when implemented within a voltage regulation system. The control technique is then applied to an experimental SRG system. Experimental operation documents that the technique provides for efficient operation of the SRG system through tuning the controller at only four operating points.