Hall Sensor Positioning for Accurate Brushless Motor Adjustment
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Solution Overview
Problem
The brushless motor control device described in WO 2018/79052 A is unable to calculate the electrical angle offset with high accuracy, resulting in inaccurate motor adjustments.
Innovation Solution
A motor adjustment method that includes a control device with an inverter circuit, current detection unit, and control unit to adjust the Hall sensor setting position by analyzing forward and reverse rotation information or polynomial approximations to determine the optimal sensor position, thereby enhancing accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the electrical angle offset is calculated based on the variation of power supply current value, then the motor adjustment can be performed, but the calculation accuracy is insufficient
Solution Approach 1:
Instead of calculating the electrical angle offset by analyzing power supply current variation (forward approach), the patent inverts the approach by injecting a known test voltage and measuring the resulting current to directly determine the offset. This inversion transforms an indirect estimation into a direct measurement, significantly improving calculation accuracy.
Solution Approach 2:
The patent introduces a test voltage injection mechanism as an intermediary to facilitate accurate offset calculation. By injecting a known voltage signal and measuring the resulting current through the inverter circuit, the system creates a controlled intermediate state that enables precise determination of the electrical angle offset without relying on noisy power supply current variations.
2Device complexity
If polynomial approximation is used to determine Hall sensor position, then calculation complexity is reduced, but measurement precision may be affected
Solution Approach 1:
The patent applies polynomial approximation as a partial solution - using it to establish the relationship between injection voltage and current for determining the electrical angle offset. This mathematical approach provides sufficient precision for the adjustment task while keeping calculations manageable, representing a balanced partial action rather than requiring full-exact complex calculations.
Data Source
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AI summary
A motor adjustment method adjusts a motor (M) driven by a control device (100). The motor adjustment method includes: acquiring forward rotation information indicating a change in a value of a current flowing through a drive unit (110) at the time of a rotor (310) rotating in a forward direction when a Hall sensor setting position is changed; acquiring reverse rotation information indicating a change in a value of a current flowing through the drive unit (110) at the time of the rotor (310) rotating in a reverse direction when the Hall sensor setting position is changed; and determining a Hall sensor adjustment position on the basis of the forward rotation information and the reverse rotation information. The Hall sensor adjustment position indicates a position obtained by adding a correction amount to the Hall sensor setting position.