External Hall Sensor Phasing for Synchronous Motor-Generator
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Solution Overview
Problem
Existing control systems for permanent-magnet synchronous electric machines used in hybrid vehicles face complexity, reliability issues, and high costs due to the use of multiple Hall probes for determining rotor position, which complicates system installation and operation.
Innovation Solution
An integrated phasing system utilizing a single external Hall sensor positioned near a toothed wheel connected to the motor-generator, which generates a magnetic flux to detect reluctance changes and provide pilot signals for phase switching, simplifying the system and reducing costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If three conventional Hall probes are used inside the rotor to sense magnetic flow direction, then rotor position can be determined with maximum error of 30 electric degrees, but system complexity increases, reliability decreases, and costs increase due to mounting support, wiring harness, and exposure to high temperatures and vibrations
Solution Approach 1:
The invention extracts the position sensing function from the internal Hall probes and relocates it to an external Hall sensor positioned outside the rotor. This extraction eliminates the need for mounting support, wiring harness, and exposure to harsh internal conditions, thereby reducing system complexity while maintaining measurement precision through the use of a single external sensor that detects rotor position via magnetic field changes
Solution Approach 2:
The invention introduces a toothed wheel as an intermediary element between the rotor and the external Hall sensor. The toothed wheel modulates the magnetic field generated by the rotor, creating distinct magnetic signatures that the external Hall sensor can detect to determine rotor position. This intermediary enables accurate position sensing without requiring internal sensors, thus reducing system complexity while maintaining measurement accuracy
2Loss of information
If three conventional Hall probes are positioned inside the rotor, then rotor position information can be obtained for converter control, but installation difficulty increases and reliability decreases due to narrow spaces, high temperatures, and vibrations
Solution Approach 1:
The invention extracts the position sensing function from the harsh internal environment and relocates it to an external Hall sensor positioned outside the rotor. This extraction eliminates exposure to high temperatures and vibrations, thereby improving reliability while maintaining position information availability through external magnetic field detection
Solution Approach 2:
The toothed wheel serves as an intermediary that transmits rotor position information to the external Hall sensor without requiring the sensor to be positioned inside the rotor. This intermediary enables reliable position detection in a benign external environment while maintaining accurate position information for converter control
3Measurement precision
If multiple Hall probes are used for rotor position detection, then position accuracy is maintained, but manufacturing costs increase due to additional components and installation requirements
Solution Approach 1:
The invention extracts the position sensing function from multiple internal Hall probes and consolidates it into a single external Hall sensor. This extraction reduces the number of components from three to one, thereby reducing manufacturing costs while maintaining position detection accuracy through external magnetic field measurement
Solution Approach 2:
The invention merges the position sensing function of multiple Hall probes into a single external Hall sensor combined with a toothed wheel mechanism. This merging reduces component count and manufacturing complexity while maintaining measurement precision through the collaborative operation of the external sensor and toothed wheel
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
This solution allows for precise synchronization of phased events in both motor and generator modes with reduced complexity and cost, enhancing system reliability and ease of installation.
Implementation Method 1
utilizing a single external Hall sensor positioned near a toothed wheel connected to the motor-generator, which generates a magnetic flux to detect reluctance changes
Data Source
Figure 1
Figure 2
Figure 3~5
AI summary
An integrated phasing system for a synchronous electric machine and engine assembly (10, 11) connected by a drive shaft (14). The electric machine (10) is firstly connected by a converter (13) to a battery (12) and used in motor mode, for starting the engine (11), that consequently drives in rotation the same electric machine (10), now running in voltage generator mode for charging the storage battery (12). A first logic control unit (15) is connected to the converter (13) to pilot the electric machine (10) according to a signal sequence supplied by a Hall sensor (18) responsive to reluctance changes caused by a toothed wheel (17) operatively connected to the drive shaft (14); the control signals supplied by the Hall sensor (18) are also used by a second electronic control unit (16) for timing phased events of the engine (11).