Wound-Rotor Synchronous Machine Sensorless Position and Speed Estimation
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Solution Overview
Problem
Existing methods for determining the position and speed of a synchronous electric machine with a wound rotor rely on mechanical sensors, which are expensive, bulky, and sensitive to environmental factors, or sensorless control methods that remain dependent on machine parameters, lacking robustness and adaptability.
Innovation Solution
A method that measures three-phase currents and injects a high-frequency voltage signal to estimate rotor position and speed independently of stator inductance values, using a demodulation step and adaptive gain calculations to refine estimates, thereby reducing dependency on machine parameters and improving robustness and simplicity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If mechanical position and speed sensors are installed on the mechanical shaft, then position and speed measurement accuracy is improved, but device complexity, cost, and sensitivity to environmental factors increase
Solution Approach 1:
The patent replaces mechanical position and speed sensors with a software-based estimation algorithm that calculates rotor position and speed from electrical current measurements. This substitution eliminates mechanical sensors entirely, reducing device complexity while maintaining measurement accuracy through mathematical modeling of the machine's electrical characteristics.
Solution Approach 2:
The patent introduces an intermediary estimation algorithm that acts as a mediator between current measurements and position/speed determination. Instead of directly measuring position and speed with sensors, the algorithm uses current signals as intermediaries to infer rotor state, avoiding the need for mechanical sensors and their associated complexity.
2Device complexity
If sensorless control methods using closed-loop estimation algorithms are used, then device complexity is reduced, but dependency on machine parameters increases
Solution Approach 1:
The patent changes the approach from using fixed machine parameters to using adaptive parameter estimation. The algorithm dynamically adjusts its internal model parameters based on real-time current measurements, allowing it to adapt to different machine configurations without requiring precise prior knowledge of inductance values or other machine-specific parameters.
Solution Approach 2:
The patent creates a universal estimation algorithm that can be applied to different wound rotor synchronous machines regardless of their specific parameters. By designing the algorithm to be parameter-independent, it achieves multi-functionality and can be used across various machine types without reconfiguration, enhancing adaptability.
3Reliability
If high-frequency signal injection methods are used, then position detection robustness is improved, but dependency on injected signal characteristics and machine parameters remains
Solution Approach 1:
The patent extracts only the essential information needed for position and speed estimation from the current signals, rather than implementing complex demodulation of high-frequency injected signals. By taking out only the necessary components and ignoring the rest, the system achieves robust position detection without the complexity of full signal demodulation and without dependency on injected signal characteristics.
Data Source
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AI summary
The invention relates to a method for estimating the speed and position of a rotor of a wound-rotor synchronous machine powered by a three-phase inverter, comprising a step of estimating the position of the rotor (Θ) according to a position gain parameter (Ke) and the sign (0'') of the calculated error (ε) and independently of the parameters of the electric machine, such as stator inductance values of the electric machine; and a step of estimating the rotor speed (œ) according to a speed gain parameter (K(J) and the sign (0'') of the calculated error (ε) and independently of the parameters of the electric machine, such as stator inductance values of the electric machine.