Modelling and reduction of current harmonics in permanent magnet synchronous machines during active noise cancellation

A nonlinear model of the permanent magnet synchronous motor (PMSM) to represent current harmonics when using Active Noise Cancellation (ANC) with electrical drives is proposed. Furthermore, a scheme to compensate for these harmonics is presented. These measures reduce the problem of unwanted harmonics when injecting a sinusoidal signal into a PMSM in standstill to cancel a narrowband disturbance with ANC. The parameters for the stated model are identified with the help of high frequency signal injection. A proportional resonant controller is used together with an input/output linearisation of the model in order to reduce the harmonics. Experiments show a good reduction especially of the dominating third harmonic for two injected frequencies.