An inductance testing method for multi-unit PMSM without any auxiliary equipment

The inductance is a key parameter for electrical machines since it has a significant impact on the performance. If the machine is expected to be controlled more precisely the inductances of the machine should be tested accurately. For inductance measurement, AC standstill test is popular applied since it is easily operated and the test result is accurate enough. However, the rotor position is fixed by auxiliary equipment in the process of testing. It makes the test cumbersome. An inductance testing method for multi-unit PMSM is presented. Inductances can be tested by this method with no need for any auxiliary equipment. It does so by exciting the direct current in one unit motor to fix the rotor position when the inductances of the other unit motor are tested. Saturation and cross-magnetization effects are considered in this method. It can be applied to test not only self and mutual inductances but also the inductances in d and q directions. The tested results are compared to the nominal value of the inductances and the method is validated.