No matter what kind of motor controller or frequency converter, there are different degrees of harmonic voltage and current in the process of operation, which make the motor run under non-sinusoidal voltage and current. Harmonic will cause the increase of copper loss of stator, rotor, iron loss and additional loss, which will directly reduce the real efficiency of the motor, and may cause the problem of excessive temperature rise. Therefore, in the design or selection of motor controller, the harmonic content of its output signal is an important index.
Solutions to the Problems of Motor Efficiency and Temperature Rise Caused by Motor Controller
Since the output signal of the motor controller should be analyzed harmonically, a broadband harmonic analyzer must be used. The current practice in the industry is to use multi-channel power analyzer to test the motor test system. As shown in the figure, the electrical and mechanical parameters of motor and driver are collected in real time during the testing process. While analyzing the real-time individual efficiency of motor and controller, the harmonic test results can also be recorded to consider the relationship between the other efficiency.