Sinusoidal Motor Control for Noise Reduction and Position Accuracy
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Solution Overview
Problem
Conventional motor control technologies face challenges with noise from square-wave drive waveforms, poor accuracy in stopping position for stepping motors, and difficulty in adjusting brushless motors after integration, especially due to the need for external power sources and exposure of rotor units.
Innovation Solution
A motor control apparatus using a sinusoidal drive waveform to control the phase of the drive waveform, incorporating a position detection unit to adjust signal output and correct for step-out deviations, allowing the motor to rapidly reach the target position by detecting and adjusting for phase mismatches during movement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If a square-wave drive waveform is used to drive the motor, then high speed and high torque are realized while preventing step-out, but a large amount of noise is generated
Solution Approach 1:
The patent changes the waveform parameter from square-wave to sinusoidal wave, eliminating harmonic components while maintaining effective torque through optimized fundamental frequency control
Solution Approach 2:
The patent removes harmful harmonic components from the drive waveform while preserving and optimizing the beneficial fundamental frequency component, achieving smooth torque delivery without noise
2Power
If a square-wave drive waveform is used to drive the motor, then high speed and high torque are realized while preventing step-out, but the accuracy of the stopping position is poor
Solution Approach 1:
The patent changes the waveform parameter from square-wave to sinusoidal wave, enabling precise position control through smooth torque variation and elimination of abrupt transitions that cause positioning errors
3Measurement precision
If conventional brushless motor adjustment methods are used, then position sensor physical position deviation is detected, but it takes much time to measure motor properties and adjust positions
Solution Approach 1:
The patent performs position detection and phase difference measurement during the initial motor rotation before operation, automatically storing correction values for future use without requiring repeated adjustments
Solution Approach 2:
The motor system automatically detects its own position sensor misalignment during initial operation and self-corrects by storing the measured phase difference for compensation during normal operation
4Measurement precision
If the rotor unit is exposed to the exterior to connect to an external power source for adjustment, then motor properties can be measured, but the adjustment becomes difficult after the motor has been incorporated into equipment
Solution Approach 1:
The motor system uses its own internal power source and control circuitry to perform self-diagnosis and self-adjustment, eliminating the need for external power sources and rotor exposure
Solution Approach 2:
The patent uses the motor's own drive circuit and control unit as intermediaries to perform measurement and adjustment functions that would otherwise require external equipment and rotor access
5Measurement precision
If conventional methods for correcting moving position are used, then positional determination is performed, but the motor must temporarily stop and it takes long time to reach the target position
Solution Approach 1:
The patent continuously detects position and corrects deviations during motor operation without stopping, maintaining continuous motion while achieving accurate positioning through real-time feedback
Solution Approach 2:
The patent uses real-time feedback from the position detection unit to continuously monitor and correct position deviations during operation, eliminating the need for stoppage-based correction
Data Source
AI summary
A motor control apparatus applying a sinusoidal drive waveform to a motor and including a position detection unit outputting a signal according to a motor shaft's position; and a control unit: acquiring a phase value of the motor's drive waveform when a signal is output by the position detection unit, changing a cycle of the drive waveform by measuring time from a previously output signal to a presently output signal, comparing the phases of the drive waveform and the motor shaft, and controlling to change to a cycle at which a phase value of the drive waveform matches a target phase value when a travel time corresponding to a phase value for adjustment has elapsed from a present time when a phase value of the drive waveform presently acquired differs from a target phase value acquired when the motor's drive current and drive voltage are in a designated phase relationship.