Motor Control Device Slope Estimation Sampling
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Solution Overview
Problem
Motor control devices face increased power consumption and heat generation due to high sampling frequencies required for accurate Hall signal conversion, leading to sampling errors that result in motor vibration and noise.
Innovation Solution
A motor control device estimates the slope of the Hall signal and determines intersection timings to obtain the rotation cycle without using high-speed AD converters, reducing sampling errors and power consumption by generating a cycle signal from multiple intersection timings, and adjusts sampling frequency based on estimated slope thresholds.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a high-speed AD converter is used to increase sampling frequency for accurate Hall signal conversion, then measurement precision is improved, but power consumption and heat generation increase
Solution Approach 1:
The patent applies dynamics by making the sampling frequency adjustable rather than fixed. The control unit dynamically changes the sampling frequency based on motor operating conditions (speed and load), using higher frequencies when needed for accuracy and lower frequencies when sufficient, thereby resolving the contradiction between measurement precision and power consumption
Solution Approach 2:
The patent changes the parameter of sampling frequency based on motor speed and load conditions. By monitoring motor operating parameters and adjusting sampling frequency accordingly, the system achieves accurate measurement only when necessary, reducing overall power consumption while maintaining measurement precision when required
2Measurement precision
If a high-speed AD converter is used to increase sampling frequency for accurate Hall signal conversion, then measurement precision is improved, but heat generation increases
Solution Approach 1:
The system dynamically adjusts sampling frequency based on actual motor conditions, avoiding continuous high-frequency sampling that generates excessive heat. The control unit activates high-speed conversion only when measurement accuracy is critically needed, thereby reducing overall heat generation while maintaining measurement precision when required
3Measurement precision
If sampling frequency is increased to reduce sampling error, then measurement precision is improved, but power consumption increases
Solution Approach 1:
The patent changes sampling frequency parameters based on motor operating conditions. By using higher sampling frequencies only when motor speed or load requires accurate position detection, and using lower frequencies during stable operation, the system reduces sampling errors when needed while minimizing overall power consumption
Data Source
AI summary
According to one embodiment, there is provided a motor control device including an acquisition unit, an AD conversion unit, a calculation unit and a drive control unit. The acquisition unit acquires an analog signal indicating a rotational position of a motor. The AD conversion unit AD-converts the analog signal to generate a digital value. The calculation unit estimates a slope of a waveform of the analog signal by using a plurality of the digital values and obtains an intersection timing at which a straight line corresponding to the estimated slope intersects with a threshold. The drive control unit controls driving of the motor according to a rotation cycle obtained from a plurality of the intersection timings.