Pulse Sensor Rotor Position Monitoring for Electric Motor Control
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Solution Overview
Problem
Existing rotational position monitoring systems for electric machines, such as resolvers, face challenges in accurately determining the rotational position and speed of rotors in multi-phase electric machines, particularly in mobile systems, where precise control is necessary for efficient torque and energy transformation.
Innovation Solution
A method employing a pulse-type rotational position sensor that monitors signal outputs and reference signals to determine the rotor position based on nominal positions, speeds, and time intervals, using the M/T method to calculate rotational speed and position, enabling precise control of electric motors through PWM signals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a resolver is used for rotational position monitoring, then the system can provide position feedback for speed and torque control, but the measurement precision and reliability are insufficient under certain operating conditions
Solution Approach 1:
The patent replaces the traditional resolver (an electromagnetic induction-based sensor) with a pulse-type sensor system that generates digital pulses. This substitution uses a different physical principle (magnetic field detection by a pulse sensor) to achieve more reliable and precise rotational position monitoring, particularly eliminating the ambiguities and errors associated with resolver signal interpretation
Solution Approach 2:
The patent introduces a pulse generator as an intermediary component between the rotor and the control system. This pulse generator produces standardized digital pulses that serve as a reliable mediator for transmitting rotational position information, replacing the direct resolver output and enabling more accurate speed and position calculation through pulse counting and timing
2Ease of manufacture
If traditional rotational position monitoring methods are used, then the system structure is relatively simple, but the torque control accuracy and energy transformation efficiency are insufficient
Solution Approach 1:
The patent implements a feedback control mechanism where pulse signals from the pulse generator are continuously monitored and used to calculate real-time rotational speed and position. This feedback information is then used by the control system to optimize motor operation, improving energy transformation efficiency and torque control accuracy while maintaining a relatively simple system structure
Solution Approach 2:
The patent changes the measurement parameters from continuous analog signals (resolver) to discrete digital pulses. This parameter change enables more precise counting and timing operations, improving the accuracy of speed and position determination, which directly enhances energy transformation efficiency and torque control
Data Source
AI summary
A method for monitoring an electric motor employing a pulse-type rotational position sensor includes monitoring a signal output from the pulse-type rotational position sensor and a reference signal associated with a control signal for the electric motor. A position of a rotor of the electric motor coincident with the reference signal is determined based upon a nominal rotor position, a nominal rotational speed of the rotor and a time between the reference signal and a falling edge of the signal output from the pulse-type rotational position sensor. The electric motor is controlled based upon the position of the rotor.