Firing angle adjustment for switched reluctance motor efficiency increasing based on measured and simulated data

This paper presents a simple turn-on and turn-off angles adjustment method to increase the efficiency of small-size switched reluctance motor (SRM) in wide speed and torque range. The simplicity of the control algorithms allows building a variable speed drive without a high-performance microcontroller and FPGA or ASIC. The firing angles calculation uses a second-order polynomial and look-up table. An increase in efficiency is demonstrated on the finite element analysis (FEA) model of SRM which was verified against measurement on an experimental test bench. Measured efficiency maps have a flat top for the investigated motor. Therefore, the angle jittering due to limited position sensor precision and 50 µs processor cycle time have a small impact on motor efficiency. The evaluation of the angle adjustment method and comparison with measurements identifies which part of the FEA model is crucial for the one-to-one implementation of the angle adjustment formulas obtained from simulation to the motor control algorithm.