Sensorless Rotor Positioning in Synchronous Reluctance Motors
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Solution Overview
Problem
Existing methods for safely operating synchronous reluctance motors without sensors are limited in accurately determining rotor position and speed, especially at low speeds and standstill, which hinders reliable sensorless control and position monitoring.
Innovation Solution
A method involving the use of test signals to determine state variables such as rotor speed and position through measuring response signals, allowing for safe operation without sensors by evaluating these variables in multiple channels, enabling robust and cost-effective positioning and monitoring.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If encoder sensors are used for safe operation of synchronous machine, then reliability of safety functions is improved, but device complexity and cost increase
Solution Approach 1:
The synchronous reluctance motor determines its own rotor position and speed using test signals injected into its stator windings and evaluating the resulting current responses. This self-measurement capability eliminates the need for external encoder sensors while maintaining reliable safety functions through sensorless control.
Solution Approach 2:
The patent replaces mechanical/optical encoder sensors with an electrical measurement system that injects test signals into the motor windings and processes the electrical current responses. This substitution eliminates moving parts and optical components, reducing device complexity while maintaining measurement reliability.
2Measurement precision
If encoder sensors are used for safe operation of synchronous machine, then measurement precision of rotor position and speed is improved, but cost increases
Solution Approach 1:
The motor system performs self-measurement by injecting test signals and evaluating its own electrical responses, eliminating the need for external measurement devices while maintaining precise rotor position and speed determination through mathematical processing of current signals.
Solution Approach 2:
The patent creates an electrical model of the motor's magnetic circuit that replicates the physical rotor position information through measured current responses. This virtual copy of position data, obtained through mathematical evaluation of test signal responses, provides precise measurement without physical sensors.
3Device complexity
If sensorless control method is used to reduce device complexity, then device complexity is reduced, but measurement precision of rotor position and speed deteriorates
Solution Approach 1:
The system continuously injects periodic test signals at specific frequencies into the motor windings and processes the resulting current responses through mathematical evaluation. This periodic measurement approach maintains high measurement precision by continuously updating rotor position and speed estimates without requiring physical sensors.
Solution Approach 2:
The patent changes the operating parameters of the motor by injecting test signals at specific frequencies and amplitudes that optimize the magnetic circuit's response for measurement purposes. By controlling the d-axis and q-axis current components separately, the system achieves precise rotor position determination through electrical parameter manipulation rather than mechanical measurement.
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
Enables reliable sensorless control and safe positioning of synchronous reluctance motors by accurately determining rotor position and speed, even at zero speed, without the need for encoder sensors, enhancing reliability and reducing costs.
Implementation Method 1
A first test signal is fed into the electrical machine (1)... A first response signal is measured... with a first state variable (4) for a rotor (5) of the electrical machine (1) being determined as a function of the first test signal (2)
Implementation Method 2
The electrical machine (1) has a rotor (5)... The synchronous reluctance machine is designed in particular in such a way that its rotor has no permanent magnets, ie is free of permanent magnets
Data Source
AI summary
In a method for operating an electric machine (1), a first test signal (2) is fed into the electric machine (1), wherein a first response signal (3) is measured, wherein a first status variable (4) for the rotor (5) of the electric machine (1) is determined according to the first test signal (2), wherein a second status variable (6) is determined for the rotor (5) of the electric machine (1), wherein the first status variable (4) and the second status variable (6) are evaluated together. For this purpose, a drive system (8) is provided, which has at least one converter (7) for driving an electric machine (1), wherein the converter (7) is provided for introducing a first test signal (2) into the electric machine (1).