Hall Sensor Motor Speed Computation Using Lookup Tables
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Solution Overview
Problem
Existing methods for computing motor speed and rotor position using hall sensors suffer from errors due to time discrepancies, leading to unstable motor control, reduced efficiency, and increased computational load, especially at high speeds, and are not cost-effective compared to resolver sensors.
Innovation Solution
A method that involves determining the time of signal change in a hall sensor using an internal clock counter, calculating motor speed and rotor position based on precise time measurements, and recording these values in a microcomputer to improve accuracy and reduce errors, while utilizing an inexpensive hall sensor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the time interval Tc for confirming the hall sensor signal is decreased to reduce computation errors, then the measurement precision of motor speed and rotor position is improved, but the computation load of the CPU increases
Solution Approach 1:
The patent applies preliminary action by pre-calculating and storing lookup tables for motor speed and rotor position computations. The CPU pre-processes the relationship between hall sensor signals and motor parameters, storing the results in memory for direct retrieval during operation. This eliminates the need for real-time complex calculations, thereby maintaining high measurement precision while significantly reducing the computation load during actual motor control operations.
2Ease of manufacture
If the hall sensor is used instead of the resolver sensor to reduce cost, then the manufacturing cost is reduced, but the measurement precision of motor speed and rotor position deteriorates
Solution Approach 1:
The patent applies parameter changes by modifying the computational parameters and algorithms used to process hall sensor signals. Instead of directly using the raw hall sensor signals, the system applies specific calculation methods including lookup tables and interpolation techniques that transform the hall sensor data into accurate motor speed and rotor position values. This allows the system to achieve measurement precision comparable to resolver sensors while maintaining the cost advantage of using hall sensors.
3Device complexity
If the typical method for computing motor speed using hall sensor is used, then the device complexity is reduced, but the measurement precision of motor speed and rotor position deteriorates due to time errors
Solution Approach 1:
The patent applies feedback by continuously monitoring the hall sensor signals and using the computed motor speed and rotor position to refine subsequent measurements. The system incorporates feedback mechanisms where the calculated parameters are used to adjust and improve the accuracy of ongoing measurements, compensating for time errors and other inaccuracies. This feedback loop maintains high measurement precision without significantly increasing device complexity.
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
This approach allows for more accurate computation of motor speed and rotor position at high speeds, enhancing control efficiency and reducing costs by using a cost-effective hall sensor, thereby improving motor control and fuel efficiency in vehicles.
Implementation Method 1
a hall sensor for detecting revolutions per minute (RPM) of each motor to more precisely control driving of the motors
Data Source
AI summary
A method and system for computing a motor speed and a rotor position using a hall sensor are provided. The method improves precision for computing the speed of the motor rotating at a high speed and the rotor position using the hall sensor based on configurations, such as the hall sensor mounted in the motor as a position sensor, a motor controller configured to receive a signal of the hall sensor to operate the motor, and a microcomputer configured to store a time when the motor controller senses the timing of a change in the signal of the hall sensor.