Torque ripple reduction of multiple harmonic components

摘要

An electric motor system includes a motor configured to produce a torque signal in response to a torque command. The torque signal has a fundamental frequency component, a first ripple harmonic and a second ripple harmonic. The first ripple harmonic is an integer multiple of the fundamental frequency component. The second ripple harmonic is an integer multiple of the first ripple harmonic. A system and method is provided to generate a ripple reduction signal in response to the torque command that simultaneously cancels the first and the second ripple harmonic in the torque signal. The second ripple harmonic may be canceled with the first ripple harmonic by being projected onto the first ripple harmonic through a transformation matrix.

主权项

1. An electric motor system comprising:
a motor configured to produce a torque signal in response to a torque command, the torque signal having a fundamental frequency component, a first ripple harmonic and a second ripple harmonic; wherein the first ripple harmonic is an integer multiple of the fundamental frequency component and the second ripple harmonic is an integer multiple of the first ripple harmonic; a controller operatively connected to the motor and configured to generate a first and a second cancellation command to cancel the first and the second ripple harmonic, respectively; wherein the controller is configured to project the second cancellation command onto the first cancellation command through a transformation matrix to thereby generate a combined cancellation command to simultaneously cancel the first and the second ripple harmonic in the torque signal; wherein the transformation matrix is dependent on a first harmonic angle (θ6), the first harmonic angle (θ6) defining an orientation of a first harmonic synchronous reference frame relative to a fundamental synchronous reference frame; wherein the transformation matrix is an inverse matrix of a first matrix (TH6); the first matrix (TH6) being defined as:TH⁢⁢6=[1-2⁢sin2⁢θ6-2⁢⁢sin⁢⁢θ6⁢cos⁢⁢θ62⁢⁢sin⁢⁢θ6⁢cos⁢⁢θ61-2⁢sin2⁢θ6];and
wherein the controller is configured to generate a ripple reduction signal in response to the torque command, the ripple reduction signal being dependent upon the combined cancellation command and predetermined characteristics of the motor.