Motor Control Device Torque Ripple Compensation Phase Correction
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Solution Overview
Problem
Existing motor control systems fail to effectively suppress torque ripple regardless of changes in the carrier frequency of the PWM signal, leading to inadequate control current characteristics and response delays.
Innovation Solution
A motor control device with a torque ripple compensation part that adjusts the PWM signal based on the motor torque command value, rotation state, and carrier frequency, incorporating a phase correction mechanism to maintain effective torque ripple suppression across varying carrier frequencies.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the carrier frequency of PWM signal is modified, then the control current characteristics and response delay change according to motor torque, but the effect of suppressing torque ripple cannot be sufficiently obtained
Solution Approach 1:
The patent applies dynamics by making the torque ripple compensation value variable according to the carrier frequency. The compensation value is dynamically adjusted based on the selected carrier frequency (first or second frequency) and the torque command value, ensuring effective torque ripple suppression regardless of which carrier frequency is used. This resolves the contradiction by adapting the compensation parameters to match the operating conditions.
Solution Approach 2:
The patent changes parameters by establishing different torque ripple compensation values corresponding to different carrier frequencies. When the carrier frequency changes from the first frequency to the second frequency, the compensation value is adjusted accordingly. This parameter change approach ensures that torque ripple suppression effectiveness is maintained across different operating conditions, resolving the technical contradiction.
2Reliability
If a fixed torque ripple compensation value is used, then the torque ripple suppression works for a specific carrier frequency, but it becomes ineffective when the carrier frequency is changed
Solution Approach 1:
The system dynamically selects the appropriate torque ripple compensation value based on the current carrier frequency. The control unit determines whether to apply a first torque ripple compensation value (for first frequency) or a second torque ripple compensation value (for second frequency), making the compensation adaptive to frequency changes rather than fixed.
Solution Approach 2:
The patent implements parameter changes by storing multiple torque ripple compensation values in memory, each corresponding to a specific carrier frequency. The control unit retrieves and applies the appropriate compensation value based on the active carrier frequency, ensuring continuous effective torque ripple suppression across different operating conditions.
3Device complexity
If the torque ripple compensation value is not adjusted according to carrier frequency, then the control system remains simple, but phase deviation occurs and torque ripple suppression becomes ineffective
Solution Approach 1:
The patent applies preliminary action by pre-calculating and storing torque ripple compensation values for different carrier frequencies before actual operation. The control unit simply retrieves the appropriate pre-computed compensation value based on the selected carrier frequency, avoiding complex real-time calculations while maintaining effective torque ripple suppression.
Solution Approach 2:
The control system serves itself by automatically selecting the appropriate torque ripple compensation value based on the carrier frequency without requiring external intervention or complex decision-making. The system self-adjusts the compensation parameters according to its operating state, maintaining simplicity while ensuring effectiveness.
Data Source
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AI summary
A motor control device includes a switching element that controls a motor, a current control part that outputs a PWM signal for driving the switching element, and a setting part that sets a carrier frequency of the PWM signal. Further, a motor control part includes a torque ripple compensation part that sets a torque ripple compensation value based on a motor torque command value, the carrier frequency, and a rotation state of the motor. The current control part outputs the PWM signal based on the motor torque command value and the torque ripple compensation value.