Sensorless Rotor Angle Detection in Reluctance Machines
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Solution Overview
Problem
Reluctance machines, particularly synchronous reluctance machines without amortisseur, face challenges in determining rotor frequency and angle without rotational speed and position sensors, which is crucial for efficient operation and synchronization with converters, especially in applications like pumps and ventilators.
Innovation Solution
A method involving a temporal sequence of voltage pulses applied to the stator winding of the reluctance machine, where the resulting electric current response is analyzed to determine the rotor frequency and angle using a control device, leveraging the magnetically anisotropic rotor core to produce a distorted current trajectory from which the rotor position and frequency can be extracted.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If rotational speed and position sensors are installed in the reluctance machine, then the rotor frequency and angle can be accurately determined, but the manufacturing cost and device complexity increase
Solution Approach 1:
The system uses the machine's own stator winding and rotor structure to generate measurement signals. By applying voltage pulses to the stator winding and analyzing the resulting current response through the magnetically anisotropic rotor core, the system determines rotor frequency and angle without external sensors, making the system self-measuring and eliminating additional hardware complexity
Solution Approach 2:
The patent replaces mechanical/electrical sensors with a field-based measurement approach. Instead of using physical sensors to detect rotor position and speed, the system uses electromagnetic field interactions between the stator winding and rotor core to indirectly determine rotor parameters through current response analysis
2Reliability
If sensors are installed to measure rotational speed and position, then converter synchronization can be achieved, but the energy efficiency and cost-effectiveness are reduced
Solution Approach 1:
The system achieves converter synchronization by using the machine's own electromagnetic characteristics. The control device analyzes the current response generated by the interaction between the applied voltage pulses and the magnetically anisotropic rotor core to determine rotor frequency and angle, enabling precise converter synchronization without additional energy-consuming sensors
Solution Approach 2:
The system changes the operating parameters by applying specific voltage pulse sequences to the stator winding and analyzing the resulting current response characteristics. By monitoring changes in current magnitude and phase relative to the applied voltage pulses, the system extracts rotor frequency and angle information for converter synchronization
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 operation of reluctance machines by allowing precise synchronization of the converter with the rotor, enhancing energy efficiency and cost-effectiveness by eliminating the need for sensors and ensuring correct rotational speed and phase connection, applicable to drives for pumps and ventilators.
Implementation Method 1
the rotor having a magnetically anisotropic rotor core
Implementation Method 2
determining the resulting temporal response sequence of the electric current flowing in the stator winding, which current arises due to a sequence of a magnetic flux, generated as a result of the voltage pulses, interacting with the magnetically anisotropic rotor core
Data Source
AI summary
A method for determining a rotor frequency and/or a rotor angle of a rotor of a reluctance machine, in particular without an amortisseur, is disclosed. The reluctance machine has a stator with a stator winding and the rotor has a magnetically anisotropic rotor core. The method includes applying a temporal sequence of voltage pulses to the stator winding, determining a sequential pulse response of a current flowing in the stator winding, the current being generated as a result of the voltage pulses and a flux being generated from the voltage pulses as a result of the magnetically anisotropic rotor core, and determining the rotor frequency and/or the rotor angle based on the measured sequential pulse response of the electric current by using an evaluating device.