Motor Controller Voltage Correction for High-Frequency Torque Ripple
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Solution Overview
Problem
Existing motor control systems fail to effectively reduce high-frequency torque ripple due to response delays and amplification of noise and vibration, limiting the estimation and correction of interlinkage flux and output torque at high frequencies.
Innovation Solution
A motor controller comprising a basic voltage command calculation unit, current detection unit, magnetic flux estimation unit, torque estimation unit, pulsation extraction unit, pulsation control unit, and voltage application unit, which estimates interlinkage flux and output torque based on current and voltage, extracts pulsation components, and calculates voltage command corrections to directly correct the voltage command, thereby reducing torque ripple at high frequencies without amplifying noise and vibration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the correction value is fed back to the current command to suppress torque pulsation, then the torque pulsation can be reduced at low frequencies, but the response delay prevents correction up to sufficiently high frequency and amplifies noise and vibration
Solution Approach 1:
The patent introduces a voltage command as an intermediary to bypass the slow current feedback loop. By estimating the interlinkage flux and torque ripple, then directly correcting the voltage command, the system achieves high-frequency response without the delay inherent in current-based feedback, while avoiding amplification of noise and vibration.
2Object-affected harmful factors
If the induced voltage is estimated by differentiating current to reduce high frequency components, then noise can be reduced, but the high frequency component is lost and torque ripple cannot be reduced
Solution Approach 1:
Instead of differentiating current to estimate induced voltage (which filters out high frequencies), the patent inverts the approach by integrating voltage to estimate interlinkage flux. This inversion preserves high-frequency components while still reducing noise, enabling effective torque ripple suppression at high frequencies.
3Manufacturing precision
If the torque ripple component is fed back to the torque command, then torque pulsation can be reduced, but the response delay prevents correction up to sufficiently high frequency
Solution Approach 1:
The patent performs preliminary action by estimating the torque ripple and calculating the voltage correction in advance, before the slow feedback loop would introduce delay. By directly adjusting the voltage command based on real-time torque ripple estimation, the system eliminates the time loss associated with traditional torque command feedback.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution enables accurate estimation and correction of interlinkage flux and output torque up to high frequencies, effectively reducing torque ripple and noise amplification, allowing for precise voltage control and improved motor performance.
Implementation Method 1
a magnetic flux estimation unit that estimates an interlinkage flux interlinked to the winding, based on an applied voltage applied to the winding and a detection value of the current
Implementation Method 2
a torque estimation unit that estimates an output torque of the motor, based on the detection value of the current and an estimation value of the interlinkage flux
Data Source
AI summary
To provide a controller for motor which can reduce a torque ripple up to high frequency, without amplifying unnecessary noise and vibration. A controller for motor estimates an interlinkage flux based on the applied voltage and the detection value of current; estimates an output torque based on the detection value of current and the estimation value of interlinkage flux; extracts a pulsation component from the estimation value of output torque; calculates a voltage command correction value based on the extraction value of pulsation component; calculates a voltage command after superimposing by superimposing the voltage command correction value on the voltage command basic value; and applies voltage to winding based on the voltage command after superimposing.