Motor Rotation Angle Measurement Using Compensating Pulses
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Solution Overview
Problem
Current methods for measuring the rotation angle of synchronous electric machines face challenges such as high cost, low accuracy, and reliability issues, particularly due to electromagnetic interference and limited resolution in non-contact methods, and the need for mechanical structures in contact methods.
Innovation Solution
A non-contact electric machine rotation angle measurement device that uses a signal conditioning circuit to generate square wave signals from three-phase output voltages and a processor to generate compensating pulses based on the time interval between six-fold frequency pulses, allowing for accurate calculation of the rotation angle without requiring mechanical structures or special modems.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If contact type measurement devices (photoelectric rotary encoders, resolvers, potentiometers) are used to measure rotation angle, then measurement accuracy can be improved, but measurement cost increases and system reliability decreases
Solution Approach 1:
The patent replaces mechanical contact type measurement devices with a non-contact measurement method. The measurement device does not require mechanical coupling or contact with the rotating part, thereby eliminating mechanical wear and improving system reliability while maintaining measurement accuracy through electromagnetic field-based detection.
Solution Approach 2:
The patent introduces a magnetic field as an intermediary between the rotating part and the measurement device. By detecting changes in the magnetic field caused by the rotation, the system can measure rotation angle without direct mechanical contact, thus improving both reliability and accuracy.
2Reliability
If Hall sensing chip is used to sense magnet rotation angle, then non-contact measurement is achieved, but electromagnetic interference generates heavy burred measurement data
Solution Approach 1:
The patent converts the harmful electromagnetic interference into a useful measurement signal. Instead of trying to shield against the electromagnetic field generated by the synchronous electric machine, the invention uses this field directly for measurement, thereby eliminating the need for shielding and improving measurement quality.
Solution Approach 2:
The measurement system uses the electromagnetic field naturally generated by the synchronous electric machine itself for measurement purposes. The machine's own operating field serves the dual purpose of driving the machine and enabling angle measurement, eliminating the need for separate excitation fields or shielding mechanisms.
3Ease of manufacture
If tooth profile disc or mechanical feature detection points are used for non-contact measurement, then cost is reduced and application is easier, but measurement resolution and update speed are limited
Solution Approach 1:
The patent changes the measurement parameter from mechanical position detection to electromagnetic field detection. By measuring the phase and frequency of the electromagnetic field signals, the system achieves high-resolution angle measurement and fast update speed without requiring mechanical features like tooth profile discs.
Solution Approach 2:
The patent transitions from one-dimensional mechanical position detection to multi-dimensional electromagnetic field analysis. By analyzing multiple parameters of the electromagnetic field (phase, frequency, amplitude), the system achieves superior measurement resolution and speed compared to simple mechanical feature detection.
Data Source
AI summary
Provided are a motor rotation angle measurement device and method. The device may comprise: a signal conditioning circuit, configured to receive a three-phase output voltage of a motor and separately generate three square-wave signals; and a processor, configured to generate a six-multiplying frequency pulse whenever jumping of any one of the three square-wave signals, is detected in a rotation period of a motor, generate compensation pulses between the current six-multiplying frequency pulse and a next six-multiplying frequency pulse based on a time interval between the current six-multiplying frequency pulse and a previous six-multiplying frequency pulse and a preset compensation subdivision coefficient k, and accumulate the number of the compensation pulses, wherein the number of the compensation pulses is related to the rotation angle of the motor.