EFFICIENCY IMPROVEMENT BY DRIVE COIL NUMBER OPTIMIZATION SYSTEM FOR MULTI-COIL MOTOR

It has been proposed that high-efficiency motor drive system using Multi-Coil Motor. However, when the motor has low output, the switching loss is dominant and the efficiency decreases. It cannot be improved by vector control. Therefore, we proposed the optimization of the number of drive coils and the design of ΔΣ modulator. It can reduce switching loss. We conducted measurements and showed that each of the two methods was effective in improving efficiency. Thus, we proposed a system combining the two methods. It achieved 15.2 % efficiency improvement at 100 RPM and 6.4 % efficiency at 500 RPM