Motor Rotor Position Control with Speed-Adaptive Detection
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Solution Overview
Problem
Existing motor control systems face challenges in maintaining high control accuracy and responsiveness due to limitations in detection and estimation of rotor position, particularly at high and low rotation speeds, which are exacerbated by noise interference and increased costs.
Innovation Solution
A motor control apparatus and method that utilizes a first detector for rotor position detection using a resolver and a second detector for estimation using motor current, with a switcher to switch between controls based on rotation speed and noise conditions, ensuring high accuracy and responsiveness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If resolution of rotation position detection is increased in high speed region, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The patent applies dynamics by making the detection method adaptive to rotation speed conditions. The control apparatus dynamically switches between resolver-based detection and current-based estimation depending on whether the motor is in low-speed or high-speed region, optimizing performance for each operating condition without requiring a permanently complex high-resolution detection system across all speeds
Solution Approach 2:
The patent changes the detection parameter based on operating conditions. In low-speed region, it uses resolver signals for accurate position detection, while in high-speed region, it switches to estimating rotation position from motor current characteristics, thereby maintaining adequate detection resolution without increasing device complexity
2Measurement precision
If resolver signal is used for rotation position detection, then measurement precision is improved, but object-affected harmful factors increase
Solution Approach 1:
The patent extracts and eliminates the harmful noise component from the detection system. By identifying that resolver signals contain noise that degrades control accuracy, the invention removes dependence on resolver signals in high-speed regions and instead uses motor current for rotation position estimation, thereby taking out the noise source from the detection path
Solution Approach 2:
The patent introduces motor current as an intermediary medium for rotation position detection. Instead of directly using noisy resolver signals, the system estimates rotation position from motor current characteristics, using the current as an intermediary that provides rotation position information without the noise contamination present in resolver signals
3Device complexity
If current-based estimation is used for rotation position detection, then device complexity is reduced, but measurement precision deteriorates
Solution Approach 1:
The patent makes the detection system dynamic by switching between detection methods based on rotation speed. Current-based estimation is used only in high-speed regions where it provides adequate performance, while resolver-based detection handles low-speed regions requiring higher precision, optimizing the balance between complexity and accuracy for each operating condition
Solution Approach 2:
The patent applies local quality by using different detection methods suited to different operating regions. Instead of using a single high-precision complex system everywhere, it employs current-based estimation locally in high-speed regions where simpler detection suffices, and reserves complex resolver-based detection for low-speed regions where high precision is critically needed
Data Source
AI summary
A motor control apparatus includes first and second detectors, and a switcher. The first detector detects a rotation position of a rotor using a signal from a resolver, and allows resolution of the rotation position to become lower in a region where a rotation speed of the rotor is higher than a first predetermined value, than in a region where the rotation speed is equal to or lower than the first predetermined value. The second detector estimates the rotation position using a current of the motor. The switcher switches between a first control and a second control in the region where the rotation speed is equal to or lower than the first predetermined value. The first control includes controlling the motor using the rotation position detected by the first detector. The second control includes controlling the motor using the rotation position estimated by the second detector.