Angle Sensor Position Determination Using Test Pulses
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Solution Overview
Problem
Existing methods for determining the current angular position of a rotatable magnetic component in electric drives with an odd number of pole pairs are limited by angle sensors that can only measure within a restricted range, leading to ambiguity and requiring additional components or complex calculations.
Innovation Solution
A method and device that convert the angle measurement value from a limited range to an unrestricted range using test pulses and an evaluation unit, determining the direction and sign of the magnetic field to provide a clear current angular position without additional components or complex calculations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If an AMR angle sensor is used to measure rotor angle, then measurement precision is improved within a restricted range, but the measurement range is limited to 0-180 degrees causing ambiguity
Solution Approach 1:
The patent uses test pulses as an intermediary to determine the magnetic field direction. By applying voltage pulses to stator coils and measuring the resulting current pulses, the system obtains information about the magnetic field orientation without requiring additional sensors. This intermediary measurement enables the conversion of the restricted 0-180 degree angle measurement into an unrestricted 0-360 degree position determination.
Solution Approach 2:
The patent changes the measurement parameters by using test pulses with specific voltage magnitudes and durations. By controlling the pulse parameters (voltage U, duration tpulse) and measuring the resulting current characteristics, the system extracts magnetic field direction information. This parameter-based approach allows determination of the magnetic field sign without adding physical components.
2Adaptability or versatility
If additional sensor elements are added to achieve unrestricted angle measurement, then angular measurement range is improved, but device complexity increases
Solution Approach 1:
The patent makes the existing drive control components multi-functional. The voltage generator, which normally generates operating voltages for the synchronous machine, is also used to generate test pulses for angle determination. The current measuring device, which monitors operating currents, is also used to measure test current pulses for magnetic field direction detection. This eliminates the need for separate dedicated test equipment or additional sensor elements.
Solution Approach 2:
The system performs self-diagnosis and self-characterization by using its own components to determine the magnetic field direction. The drive control unit itself generates the test pulses and evaluates the resulting current pulses, enabling the system to characterize its own operating conditions without external assistance or additional specialized components.
3Device complexity
If angle estimation methods using voltage pulses are used, then device complexity is reduced, but measurement precision and noise performance deteriorate
Solution Approach 1:
The patent implements a feedback mechanism where the measured current pulses are used to determine the magnetic field direction, which then feeds back into the angle calculation process. The control unit uses the measured current characteristics to adjust and refine the angle determination, ensuring high precision. This feedback loop allows the system to achieve accurate angle measurement while maintaining simplicity by using existing components.
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 precise determination of the current angular position in an unrestricted range, reducing computational effort and installation space, and is cost-effective due to the use of existing drive control components, suitable for electric drives with odd pole pairs.
Implementation Method 1
A known possibility is the use of a transmitter magnet and an AMR angle sensor, i.e. an angle sensor that uses an anisotropic magnetoresistive effect
Implementation Method 2
The AMR angle sensor can be combined with two Hall sensors to obtain a clear angle signal in the unrestricted angle range from 0 to 360°
Implementation Method 3
the voltage induced in the stator coils of the synchronous machine depends on the rotor angle
Implementation Method 4
the inductances of the stator coils can depend on the rotor angle, depending on the design of the synchronous machine
Data Source
Figure 1~2
Figure 3~5
AI summary
The invention relates to a method for determining the actual angle position of a rotatable magnetic component in an electric drive (10) having an odd number of pole pairs. An actual angle measurement value (fAMR,k) of the rotatable component is measured using an angle sensor (28) which only measures the actual angle measurement value (fAMR,k) within a predefined reduced angular area, and an associated device (20) for determining an actual angle position of a rotatable magnetic component in an electric drive (10). According to the invention, the actual angle measurement value (fAMR,k) measured exclusively for the reduced angular area is converted using the direction and the sign of the magnetic field of the rotatable magnetic component in a clear angular position in non-reduced angular area, the direction and sign of the magnetic field of the rotatable magnetic element (12) being determined by applying first test impulses (Ua, Ub, Uc) to the electric drive (10) and by evaluating the resulting second test impulses (I1, I2, Ia, Ib, Ic) which are produced in the electric drive (10) in reaction with the applied first test impulses (Ua, Ub, Uc).