Position Sensor Self-Calibration for Motor Alignment
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Solution Overview
Problem
Existing position sensors for electric commutated motors, such as BLDC and PMSM, require complex zero angle programming and alignment processes, which are system-specific and labor-intensive, often necessitating additional hardware and current sources for calibration.
Innovation Solution
A position sensor system comprising a magneto-sensitive element, signal evaluation unit, output stimulation unit, and interface unit, integrated on a semiconductor body, which allows for both measurement and calibration modes of operation, enabling self-calibration and direct feedback to the motor controller without additional equipment, using a multiplexer, SPI interface, and memory for storing calibration data.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If traditional position sensors are used for electric commutated motors, then position detection function is achieved, but complex zero angle programming and alignment processes are required
Solution Approach 1:
The patent combines the position sensor with an integrated circuit that includes both a measurement signal generator and a test signal generator on a single semiconductor substrate. This merging eliminates the need for separate calibration hardware and simplifies the zero angle alignment process by providing all necessary functions in one integrated device.
Solution Approach 2:
The interface unit in the integrated circuit is designed to output both measurement signals from the magneto-sensitive element and test signals from the test signal generator through the same output terminals. This multi-functionality allows the single device to perform both position detection and self-calibration operations without requiring additional specialized hardware.
2Measurement precision
If additional calibration equipment is used for zero angle programming, then calibration accuracy is improved, but hardware requirements and system complexity increase
Solution Approach 1:
The position sensor performs its own calibration by using an internal test signal generator that produces test signals through the same magneto-sensitive elements used for measurement. This self-service capability eliminates the need for external calibration equipment while maintaining calibration accuracy, as the sensor calibrates itself using its own resources.
Solution Approach 2:
The interface unit acts as an intermediary that manages both measurement and test signal outputs through shared terminals. It coordinates the switching between measurement mode and calibration mode, enabling the system to perform accurate calibration without requiring separate dedicated hardware paths for test signals.
3Adaptability or versatility
If separate calibration hardware is implemented, then calibration function is achieved, but device complexity and manufacturing cost increase
Solution Approach 1:
The patent merges the calibration functionality into the main sensor integrated circuit by implementing both measurement and test signal generators on the same semiconductor substrate. This consolidation simplifies manufacturing by reducing the number of discrete components and assembly steps required, while maintaining full calibration capability.
4Ease of operation
If in-line calibration is implemented, then alignment process is simplified, but signal interference may occur
Solution Approach 1:
The system operates in periodic cycles, switching between measurement mode and calibration mode through the interface unit. During calibration mode, test signals are generated and output, then the system switches back to measurement mode for normal operation. This periodic switching prevents continuous signal interference while enabling regular calibration, as the magneto-sensitive elements are exposed to test fields only during designated calibration intervals.
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
Simplifies the zero angle alignment process by allowing in-line calibration and direct motor control, reducing noise and hardware requirements, while providing accurate position feedback through incremental or absolute sensor outputs.
Implementation Method 1
A position sensor (10) comprises at least one magneto-sensitive element (11-14), a signal evaluation unit (16), an output stimulation unit (17) and an interface unit (18)
Data Source
AI summary
A position sensor (10) comprise at least a magneto sensitive element (11-14), a signal evaluation unit (16) that is coupled to the at least one magneto sensitive element (11-14) and is configured to generate an measurement signal (SM), an output stimulation unit (17) configured to generate a set signal (ST) and an interface unit (18) that is coupled at its input side to the signal evaluation unit (16) and the output stimulation unit (17). The interface unit (18) is configured to provide a sensor output signal (SOUT) depending on the measurement signal (SM) in a measurement mode of operation and depending on the set signal (ST) in a calibration mode of operation.