Integrated Point Field Detectors for Electric Machine Sensing
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Solution Overview
Problem
Existing propulsion systems for vehicles rely on costly and bulky sensors like Hall Effect sensors and resolvers for current and rotor position detection, which impede power density targets and are susceptible to environmental exposure, necessitating a more efficient and robust solution for motor control and diagnostics.
Innovation Solution
The integration of point field detectors (PFDs) within the motor housing to detect leakage flux, utilizing low-cost, lightweight magnetoresistive and Hall Effect sensing hardware, which extracts information from existing electromagnetic fields to determine multiple electric machine parameters, including current levels, rotor position, temperature, and magnetization state, thereby replacing or backing up traditional sensors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional Hall Effect sensors and resolvers are used for current and rotor position detection, then measurement precision is improved, but device complexity and weight increase
Solution Approach 1:
The patent combines multiple sensing functions into a single integrated sensor system. The sensor array includes multiple sensor elements that simultaneously detect both current information and rotor position information from the back-EMF signal, eliminating the need for separate Hall Effect sensors and resolvers. This merging reduces device complexity while maintaining measurement precision.
Solution Approach 2:
The sensor system performs multiple functions using a single detection mechanism. The same sensor array and signal processing system extract both current information and rotor position information from the back-EMF signal, making the system universal and multi-functional rather than requiring dedicated sensors for each measurement type.
2Measurement precision
If traditional Hall Effect sensors and resolvers are used for sensing, then measurement precision is improved, but weight of the propulsion system increases
Solution Approach 1:
By merging multiple sensing functions into a single integrated sensor system, the overall weight of the sensor assembly is reduced. The sensor array with shared signal processing weighs less than the combined weight of separate Hall Effect sensors and resolvers, directly addressing the weight reduction goal while maintaining measurement precision.
3Difficulty of detecting and measuring
If traditional sensors are exposed to the motor environment, then detection capability is improved, but reliability decreases due to environmental exposure
Solution Approach 1:
The patent uses the back-EMF signal as an intermediary carrier that conveys both current and rotor position information without requiring physical exposure to harsh motor environments. The sensor array detects this electromagnetic signal from a protected position, and the information is extracted through signal processing, shielding the sensors from direct environmental exposure while maintaining detection capability.
4Measurement precision
If multiple separate sensors are used for different parameters, then measurement precision for each parameter is improved, but device complexity and cost increase
Solution Approach 1:
The patent merges multiple measurement functions into a single integrated system. The sensor array detects a unified back-EMF signal that contains both current and rotor position information, and a single signal processing system extracts both parameters through mathematical operations, reducing the number of sensors and processing systems while maintaining precision for each parameter.
Solution Approach 2:
The sensor system is designed with universal multi-functionality to extract multiple parameters from a single signal source. The same hardware infrastructure processes both current information and rotor position information, making the system efficient and cost-effective while maintaining measurement precision for all parameters.
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 provides a cost-effective, compact, and reliable sensing system that enhances motor control, diagnostics, and prognostics, eliminating the need for bulky sensors and reducing exposure to harsh environments, while maintaining accurate torque and power output control.
Implementation Method 1
utilizing low-cost, lightweight magnetoresistive and Hall Effect sensing hardware
Implementation Method 2
utilizing low-cost, lightweight magnetoresistive and Hall Effect sensing hardware
Implementation Method 3
The rotor is connected to and rotating a shaft based on a magnetic field generated by the stator
Data Source
AI summary
An electric machine disposed within a housing includes a stator, a rotor, and one or more point field detectors. The stator receives current from an inverter. The rotor is connected to and rotating a shaft based on a magnetic field generated by the stator. The one or more point field detectors are configured to detect leakage flux within the housing. The stator, the rotor and the one or more point field detectors are disposed within the housing.