Sensorless Rotor Angle Control via Test Signal Correlation
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Solution Overview
Problem
Conventional synchronous machines require position sensors for optimal torque control, increasing complexity, cost, and reducing reliability, while also needing additional installation space and being prone to sensor errors.
Innovation Solution
A method for sensorless control of separately excited synchronous machines using a test signal, such as a PRBS signal, to determine and adapt the rotor angle based on error signals measured in coordinate systems like dq or αβ, eliminating the need for position sensors and reducing dependency on motor parameters.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a position sensor is used to detect rotor angle, then control precision is improved, but device complexity increases and reliability decreases
Solution Approach 1:
The patent extracts and eliminates the position sensor from the system by replacing it with a sensorless control method. The rotor position is determined mathematically using motor model parameters and measured currents/voltages, rather than through physical sensing. This removes the sensor component entirely, reducing device complexity while maintaining control precision through computational methods.
Solution Approach 2:
The patent replaces the mechanical/electrical sensor system with a computational/mathematical system. Instead of using physical sensors to detect rotor position, the system uses mathematical models and signal processing to calculate position from electrical measurements. This substitution eliminates mechanical wear and sensor failures while maintaining detection accuracy.
2Measurement precision
If a position sensor is installed in the rotor, then rotor angle detection is improved, but installation space requirements increase and costs increase
Solution Approach 1:
The patent removes the position sensor from the rotor assembly, eliminating the need for additional installation space within the motor structure. The sensorless method determines rotor angle using existing electrical measurements and mathematical computation, requiring no physical space for sensor installation in the rotor or stator.
3Productivity
If conventional sensor-based control is used, then torque control accuracy is improved, but system reliability decreases due to sensor failures
Solution Approach 1:
The patent replaces the vulnerable sensor-based detection system with a robust computational approach. By using mathematical models and signal processing to determine rotor position from electrical measurements, the system eliminates sensor failure modes while maintaining torque control accuracy through continuous calculation and adaptation.
Solution Approach 2:
The patent implements continuous feedback through mathematical modeling, where the system constantly monitors electrical currents and voltages, compares them with expected values from the motor model, and adjusts the control accordingly. This feedback mechanism maintains accurate torque control without relying on physical sensors that can fail.
4Measurement precision
If sensor signals are compensated and sensor errors are diagnosed, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The patent extracts and eliminates the need for sensor signal compensation and error diagnosis by removing the sensor entirely. Instead of processing and correcting sensor signals, the system directly calculates rotor position from electrical measurements using mathematical models, avoiding all sensor-related complexity and error sources.
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 efficient torque production without sensors, saving costs and space, with high accuracy and reduced computational complexity, ensuring optimal performance even at low speeds and varying conditions.
Implementation Method 1
determining an error signal by correlating the measured characteristic variable of the electrical current driving the rotor with a temporally delayed test signal which is determined from the test signal which has been fed in
Data Source
AI summary
A method for sensorless control of a separately excited synchronous machine having a rotor includes the following steps: feeding a test signal on a parameter of an electrical current driving the rotor; measuring the parameter of the electrical current driving the rotor on an axis of the coordinate system describing the synchronous machine; determining an error signal by correlating the measured parameter of the electrical current driving the rotor with a temporally delayed test signal which is determined from the fed test signal; and adjusting a rotor angle as a reaction to the error signal if the error signal has a value not equal to zero.