STUDY ON EFFICIENCY DETERIORATION DUE TO MAGNETIC SATURATION AND EFFICIENCY IMPROVEMENT OF RELUCTANCE MOTOR

点击翻译按钮获取中文摘要

During the financial support by this research project, grant-in-aid for scientific research, efficiency deterioration due to magnetic saturation and its improvement strategy of a synchronous reluctance motor are studied and the following results were obtained :(1)Stator winding resistance, d-axis inductance and q-axis inductance were accurately measured with a 1-kW synchronous reluctance motor, and it was confirmed that the both inductances can approximately be expressed as logarithmic functions with respect to each axis current.(2)Operation algorithm to maximize the efficiency of the motor was discussed for both cases with only copper loss and with copper and iron losses, using the above magnetic saturation mathematical model. The optimum magnetizing current characteristic was mathematically derived as a function of a torque current. The feasibility study was done through computer analysis by using parameter data measured the above tests.(3)An experimental system was set up with 2 syn … More chronous reluctance motors with identical ratings. Also, a fully digital controller was set up by using a standard computer, A/D and D/A converter boards real-time OS(RT-Linux) and controlled simultaneously the test machine and the load machine.(4)Experimental comparison has been conducted to evaluate feasibility of the proposed method, compared the proposed method with two conventional methods. As a result, motor efficiency was improved by 6.4 points, compared the proposed method with the constant magnetizing current method. Also, compared with the conventional maximum-efficiency operation method, i.e.id=iq, the proposed method surpasses the conventional method with 5.4 point efficiency improvement.(5)The true maximum-efficiency operating points were experimentally searched by changing the magnetizing current under constant speed and constant load conditions. The sought operating points were confirmed to be slightly less than the theoretically derived operating points to achieve the maximum efficiency, while both of the operating characteristic curves are quite similar non-linear functions of the torque current. This fact proved that the proposed magnetizing current condition was effective to improve the motor efficiency further. Less