Harmonic compensation is a general name for compensating harmonic disturbances to the motor motion. A harmonic disturbance is one that is synchronized to the motor position, at either the same frequency of the motor rotation or a multiple of that frequency. Servotronix customers have benefited from our algorithmic knowledge and our ability and willingness to customize specific product firmware in order to compensate for various harmonic disturbances in their systems.
There are a number of sources of harmonic disturbance. Cogging is a term used to describe non-uniform force or torque that is caused by magnetic interactions between magnets and the rotor slots in Permanent Magnet Brushless DC motors. In general, the cogging disturbance increases as the number of motor poles decrease. However, the motor price increases as the number of poles increase. Magent skewing is used to reduce the effect of the cogging. Compensation in the servo drive via algorithms is not simple, due to the extremely high bandwidths that would be required to do this.
Harmonic disturbances can occur when using sin/cos feedback devices, and this is a result of mismatches between the phase and gain of the sine and cosine signals. Servotronix provides tuning facilities within our products to measure and compensate for these disturbances.
We also compensate for load disturbances and we have developed special algorithm to do this automatically and on the fly. A feedback sensor on the load is a prerequisite for this capability to be implemented.
Please contact us at info@servotronix.com to get information about how we can help with your application.