Hairpin Stator Neutral Bar Temperature Sensing for EV Motors
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Solution Overview
Problem
Existing electric machines in hybrid and electric vehicles lack effective temperature sensing and control mechanisms, leading to potential overheating and reduced performance or safety issues.
Innovation Solution
Incorporating a thermistor or temperature sensor within the electric machine, specifically secured to the neutral bar or hairpin windings, to monitor and communicate temperature data to a controller, which adjusts the power output accordingly to prevent overheating.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If no temperature sensing mechanism is installed in the electric machine, then the device complexity is reduced, but the reliability and safety deteriorate due to potential overheating
Solution Approach 1:
The temperature sensing function is merged with the existing neutral bar structure by placing the thermistor inside an orifice of the neutral bar. This integration approach adds temperature monitoring capability without requiring separate sensing components or additional structural elements, thus improving reliability while minimizing device complexity
Solution Approach 2:
The neutral bar serves dual purposes: it provides electrical connection for the hairpin windings and simultaneously houses the temperature sensor. This self-service approach allows the existing structure to fulfill multiple functions, avoiding additional complexity from dedicated sensing mechanisms
2Reliability
If a temperature sensor is added to monitor electric machine temperature, then the reliability improves, but the device complexity increases
Solution Approach 1:
The thermistor provides continuous temperature feedback to the controller, enabling real-time monitoring and control adjustments. The feedback mechanism uses simple resistance-based temperature sensing that communicates with the existing controller, improving reliability through continuous monitoring without adding complex control systems
Solution Approach 2:
The neutral bar acts as an intermediary structure that houses the thermistor and provides thermal coupling between the hairpin windings and the sensor. This intermediary approach enables temperature monitoring while using existing structural components, avoiding direct addition of complex sensing apparatus
3Measurement precision
If the thermistor is placed inside the orifice of the neutral bar, then the temperature sensing accuracy improves, but the manufacturing precision requirements increase
Solution Approach 1:
The thermistor is nested within the orifice of the neutral bar, creating a compact integrated sensing arrangement. This nesting approach ensures close thermal coupling for accurate temperature measurement while the orifice dimensions and positioning can be standardized during manufacturing, balancing measurement precision with manufacturability
Solution Approach 2:
The orifice in the neutral bar is specifically designed with particular dimensional characteristics to optimize thermistor placement and thermal contact. This localized structural feature provides precise temperature sensing at the critical neutral bar location without requiring high precision throughout the entire manufacturing process
4Ease of operation
If the clip is designed to secure the thermistor to the hairpin windings, then the ease of operation improves, but the device complexity increases
Solution Approach 1:
The securing function is extracted as a separate clip component that can be independently designed and manufactured. This clip mechanically attaches the thermistor to the hairpin windings, providing easy installation and removal while keeping the main electric machine structure simple and avoiding integrated complexity
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 enables real-time temperature monitoring and control, enhancing the electric machine's performance, reliability, and safety by preventing overheating and optimizing power output based on temperature conditions.
Implementation Method 1
The thermistor is disposed within the orifice and is configured to sense a temperature of the electric machine
Implementation Method 2
The sensor is configured to sense a temperature of the electric machine and communicate the temperature to a controller
Implementation Method 3
The stator is configured to generate a magnetic field that interacts with the rotor to generate rotational motion
Data Source
AI summary
A vehicle includes a battery, an electric machine, a thermistor, and a controller. The electric machine is configured to draw electrical power from the battery to propel the vehicle. The electric machine has a rotor and a stator. The stator has a core, interconnected hairpins, and a neutral bar. The core defines slots. The interconnected hairpin windings are arranged within the slots and are arranged to form a plurality of electrical phases. The neutral bar is connected to each of the electrical phases and defines an orifice. The thermistor is disposed within the orifice and is configured to sense a temperature of the electric machine. The controller is programmed to control a power output of the electric machine based on the temperature of the electric machine.