Electric Motor Torque Ripple Cancellation via Harmonic Projection
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Electric motor systems with interior permanent magnet motors experience undesirable torque ripple, leading to unwanted vibration and noise due to alternating magnetic poles and windings, which existing technologies have not effectively addressed.
Innovation Solution
A controller-generated ripple reduction signal is created by projecting a second cancellation command for the second ripple harmonic onto a first cancellation command for the first ripple harmonic through a transformation matrix, effectively canceling both harmonics in the torque signal, thereby reducing torque ripple.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If traditional motor control is used, then the motor produces torque, but torque ripple causes vibration and noise
Solution Approach 1:
The torque ripple cancellation is segmented into multiple harmonic components (first ripple harmonic and second ripple harmonic). Each harmonic is independently identified and canceled through separate transformation matrices, allowing systematic reduction of vibration and noise without overwhelming system complexity
Solution Approach 2:
A controller acts as an intermediary between the motor's torque production and the final output. The controller generates ripple reduction signals by transforming and canceling harmonic components before they manifest as vibration and noise, effectively mediating the harmful effects while preserving useful torque
2Manufacturing precision
If multiple ripple harmonics are canceled simultaneously, then torque ripple is reduced, but control complexity increases
Solution Approach 1:
The control algorithm segments the torque ripple into distinct harmonic components (first and second ripple harmonics). Each component is processed separately through its own transformation matrix, enabling precise cancellation while maintaining manageable algorithmic complexity through modular processing
Solution Approach 2:
The control approach transforms the torque ripple cancellation problem from the time domain to the frequency domain using harmonic analysis. By working with transformation matrices in the frequency domain, the system achieves precise multi-harmonic cancellation that would be extremely complex to implement in the time domain
Data Source
AI summary
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.