Reduce the Waveform Distortion Using High-Order Harmonical Driving Current for a Vibrator

A method to reduce waveform distortion is proposed and experimentally verified for vibrators driven by voice coil motors. In this method, a current including high-order harmonics is synthesized to drive the vibrator. The amplitudes and phases of the high-order harmonics are calculated based on the measured parameters which are correlated with the distortion. These parameters include the displacement dependence of the vibrator stiffness and that of the magnetic force per unit current. The calculation model is built on the nonlinear vibrator dynamic equation. By minimizing the lower order harmonics of the output acceleration, a series solution is obtained to synthesize the driving current. The feasibility has been demonstrated by Simulink simulation. Applying this strategy to a home-made vibrator, the waveform distortion of vibration acceleration has been reduced from 9.60% to 1.22%. The proposed method provides an alternative technology to reduce the distortion. This technology is especially useful in case that it is difficult to reduce the nonlinearity of the vibrator.