Rotor Angular Position Estimation Using Counter Signals
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Solution Overview
Problem
Traditional motor control systems for electric vehicles rely on high-resolution sensors to accurately estimate angular position and velocity of the rotor, which increases costs; low-resolution sensors introduce substantial errors, degrading control performance and torque accuracy.
Innovation Solution
A method for estimating angular position and velocity using counter output signals to compute and adjust angular position and velocity signals, allowing for the use of low-resolution sensors by processing differences in pulse counts and time durations between control periods.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If high-resolution sensors are used to accurately estimate angular position and velocity, then measurement precision is improved, but device cost and complexity increase
Solution Approach 1:
The patent replaces the mechanical sensor system with a signal processing system. Instead of using high-resolution physical sensors to directly measure rotor position and velocity, the system uses a low-resolution sensor in combination with counter output signals and computational algorithms (including pulse counting, time duration measurement, and signal processing) to estimate angular position and velocity. This substitution of mechanical measurement with computational estimation resolves the contradiction by achieving high measurement precision through software processing rather than hardware complexity.
2Device complexity
If low-resolution sensors are used to reduce device cost, then device complexity is reduced, but measurement precision deteriorates due to substantial errors in angular position and velocity estimation
Solution Approach 1:
The patent introduces counter output signals as an intermediary between the low-resolution sensor and the control system. The counter signals provide additional information about rotor position and velocity that, when processed through computational algorithms, compensate for the limitations of the low-resolution sensor. This intermediary mechanism enables the system to achieve accurate angular position and velocity estimation despite using cost-effective low-resolution sensors.
Solution Approach 2:
The system implements feedback through the use of counter output signals that continuously provide information about rotor position and velocity. By processing these feedback signals through computational algorithms (including pulse counting and time duration measurement), the system can accurately estimate angular position and velocity and use this information to improve control performance, thereby overcoming the limitations of low-resolution sensors.
3Device complexity
If low-resolution sensors are used to decrease system cost, then device cost is reduced, but control performance and torque accuracy deteriorate due to estimation errors
Solution Approach 1:
The patent replaces reliance on high-resolution physical sensors with a computational estimation system that processes counter output signals. This substitution maintains control performance and torque accuracy by using algorithms that compute angular position and velocity from the counter signals, thereby achieving reliable control without the cost of high-resolution sensors.
Solution Approach 2:
The counter output signals serve as an intermediary that bridges the gap between low-resolution sensors and the control system. These signals contain encoded information about rotor position and velocity that, when processed through computational algorithms, provide accurate estimates for control purposes. This intermediary mechanism preserves control performance and torque accuracy while enabling the use of cost-effective low-resolution sensors.
Data Source
AI summary
Embodiments of the present disclosure relate to methods, systems and apparatus for estimating angular position and/or angular velocity of a rotor of an electric machine.