Door Drive Motor Winding Temperature Detection via Resistance
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Solution Overview
Problem
Existing methods for determining the temperature of electric motor windings, such as those in electric door drive motors, suffer from latency issues with temperature sensors, leading to power reserve requirements and increased complexity and failure susceptibility, and require additional installation space.
Innovation Solution
Determine the temperature of the motor winding by measuring electrical resistance using a current-sensing resistor, eliminating the need for separate temperature sensors by correlating resistance values with tabulated resistance-temperature pairs obtained during a factory reference measurement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If temperature sensors are used to determine motor winding temperature, then temperature monitoring is achieved, but latency occurs between heating and detection
Solution Approach 1:
The patent uses electrical resistance as an intermediary parameter to indirectly measure temperature. Instead of directly sensing temperature with a sensor that has latency, the system measures resistance (which changes instantaneously with temperature) and correlates it to temperature through resistance-temperature value pairs. This intermediary measurement approach eliminates detection latency while maintaining temperature measurement accuracy.
Solution Approach 2:
The patent replaces the thermal sensing mechanism (temperature sensors that detect heat physically) with an electrical measurement mechanism (resistance measurement). By substituting the mechanical/thermal detection system with an electrical system, the invention achieves instantaneous temperature determination through resistance measurement, eliminating the time delay inherent in thermal sensor response.
2Reliability
If temperature sensors are installed in the motor, then temperature monitoring is enabled, but device complexity and failure susceptibility increase
Solution Approach 1:
The patent makes the existing current-sensing resistor serve multiple functions: it continues to provide current sensing for motor control while simultaneously enabling temperature determination through resistance measurement. By making this component multi-functional, the system achieves temperature monitoring capability without adding separate temperature sensors, thereby reducing device complexity and potential failure points while maintaining protection capability.
Solution Approach 2:
The patent merges the temperature measurement function with the existing current sensing circuitry. Instead of having separate temperature sensors and current sensing components, the system combines these functions by using the current-sensing resistor's resistance measurement to determine both current and temperature, thereby reducing component count and system complexity.
3Measurement precision
If temperature sensors are added to the motor, then temperature detection is achieved, but installation space requirements increase
Solution Approach 1:
The patent extracts the temperature sensing function from separate physical temperature sensors and integrates it into the existing electrical circuit through resistance measurement. By taking out the temperature detection capability from dedicated sensor hardware and embedding it in the electrical measurement system, the invention eliminates the need for additional installation space while maintaining temperature detection precision.
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 accurate and instantaneous temperature determination without latency, allowing the electric motor to operate at its power limit while preventing overheating, reducing complexity and failure risk, and minimizing installation space.
Implementation Method 1
the electrical resistance changes almost instantaneously with the temperature of the motor winding
Implementation Method 2
determining the electrical resistance of the motor winding from the quotient of voltage to current
Data Source
AI summary
The present invention relates to a method for determining the temperature of a motor winding (11a, 11b, 11c) of an electric motor (1), in particular an electric door drive motor. According to the invention, the electrical resistance of the motor winding (11a, 11b, 11c) is determined as a measure of the temperature.