Electrical Angle Calculation Using Embedded Hall Sensors
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Solution Overview
Problem
Existing methods for calculating the electrical angle of a brushless direct-current motor (BLDC) using external rotary encoders are not advantageous in terms of size and cost reduction.
Innovation Solution
An electrical angle calculation device and method that extracts and calculates the electrical angle using output signal values from Hall sensors embedded in the motor, involving signal value extraction, normalization, phase index identification, and calculation sections to determine the angle without an external encoder.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If an external rotary encoder is used to acquire the electrical angle, then the measurement precision of the electrical angle is improved, but the device size and cost increase
Solution Approach 1:
The patent extracts the electrical angle measurement function from the external rotary encoder and implements it using the existing Hall sensors embedded in the motor. By processing the output signals from these Hall sensors through signal value extraction and electrical angle calculation sections, the system achieves electrical angle measurement without requiring an external encoder, thereby reducing device size and cost while maintaining measurement capability
Solution Approach 2:
The motor's own embedded Hall sensors are utilized to perform the electrical angle measurement function that would otherwise require an external encoder. The Hall sensors, which are already part of the motor structure, are made to serve the dual purpose of their original function and electrical angle detection, eliminating the need for additional external components
2Device complexity
If Hall sensor outputs are used to calculate electrical angle, then the device size and cost are reduced, but the measurement precision may deteriorate
Solution Approach 1:
The patent applies preliminary signal processing actions to the Hall sensor outputs before electrical angle calculation. The signal value extraction section pre-processes the Hall sensor signals by extracting specific signal values that monotonously increase or decrease with electrical angle, and the signal normalization section performs normalization to improve signal quality. These preliminary actions enhance the measurement precision of the electrical angle calculation while using only the embedded Hall sensors
Solution Approach 2:
The patent transforms the raw Hall sensor signals into improved measurement parameters through signal normalization and selective extraction. By changing the parameter representation from raw Hall sensor outputs to normalized and selectively extracted signal values, the system achieves higher measurement precision for electrical angle calculation using the same embedded sensors
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enables accurate calculation of the electrical angle using Hall sensors, reducing device size and cost while maintaining practical accuracy, with an error of approximately 5° maximum and linear correlation observed.
Implementation Method 1
output signal values of a plurality of Hall sensors embedded in a stator of the motor
Data Source
AI summary
Disclosed herein is an electrical angle calculation device including a signal value extraction section that extracts a signal value that monotonously increases or monotonously decreases with respect to an electrical angle of a motor from output signal values of a plurality of Hall sensors embedded in a stator of the motor, and an electrical angle calculation section that calculates the electrical angle from the extracted signal value.