Active Compensation Control Strategy Research Of Vibration And Noise Suppression In PMSM

There are teeth and slots on the stator of permanent magnet synchronous motor, and teeth and slots have different magnetic properties for poles of permanent magnet. The different magnetic properties of the teeth and the slots make poles on the rotor have diverse magnetic field lines at different locations. When the pole is aligned with the teeth of stator, the ferromagnetic attracted force is reduced; when the pole is aligned with the slots of stator, the ferromagnetic attracted force is increased. That will pull and shrink the stator core, and deformation of the stator structure lead to vibration and noise of the motor. Thus, pole cogging is caused by interaction on poles and slots of permanent magnet without load and radial electromagnetic force wave can cause vibration and noise of the motor. Therefore, this thesis proposes a method of active compensation to suppress vibration and noise of the motor by current active compensation on d-axis and q-axis.Firstly, under the premise of ignoring air gap saturation, analytical expressions of radial electromagnetic force wave of permanent magnet synchronous motor is derived by magnetic circuit method and principal component of no-load electromagnetic force wave is analyzed. Meanwhile, the result is validated by simulation of using finite element analysis, and the result of analytical method and finite element is identical.Secondly, co-simulation model of MATLAB/simulink and Simplorer is established. Current fitting function of three phase is added to the actual motor model in Ansoft by current fitting method. Radial magnetic density and radial electromagnetic force wave are researched by motor model in Ansoft, and vibration and noise is analyzed under SPWM modulation strategy.Thirdly, mechanism of quadruple frequency and sextuple frequency force wave is analyzed, and the thesis raised an active compensation method to suppress quadruple frequency and sextuple frequency force wave. That is realized by injecting the fifth and the seventh harmonic currents into armature winding of motor to restrain quadruple frequency and sextuple frequency force wave and vibration and noise. The active compensation control strategy is achieved by injecting the sixth harmonic currents on d-axis and q-axis.Finally, radial electromagnetic exciting force and acceleration of vibration are calculated to verify that the active compensation control strategy is surefire by the finite element method.