Rotary Electric Machine Controller Temperature Estimation
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Solution Overview
Problem
Existing controllers for AC rotary electric machines face challenges in accurately estimating transitional temperatures due to the complex interplay of copper loss, iron loss, and heat radiation, which complicates the calculation of temperature changes and can lead to delayed detection of overheating issues.
Innovation Solution
A controller that uses temperature prediction data to estimate the temperature of AC rotary electric machines by referencing the relationship between rotational speed, torque, and temperature at a reference time point, allowing for successive calculations of temperature values without requiring complex simulation calculations, thereby accurately estimating both steady and transitional temperatures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If temperature sensor is used to detect stator coil temperature, then overheat protection is provided, but detection delay occurs when heating amount is large and temperature rise is steep
Solution Approach 1:
The patent performs preliminary calculations of saturation temperature based on rotational speed and torque before actual overheating occurs. By pre-calculating temperature predictions using stored data from multiple reference speeds and torques, the system prepares temperature estimates in advance, allowing immediate detection when temperature exceeds thresholds without waiting for sensor signals.
Solution Approach 2:
The patent introduces an intermediate calculation model that uses rotational speed and torque as mediators to estimate temperature. Instead of directly measuring temperature with sensors, the system uses the relationship between speed, torque, and saturation temperature to indirectly determine temperature status, bypassing the delay inherent in physical sensor response.
2Measurement precision
If simulation calculation is used to estimate transitional temperature considering heating amount, heat radiation amount, and heat capacity, then accurate temperature estimation is achieved, but complicated calculation and high arithmetic load are required
Solution Approach 1:
The patent segments the temperature estimation problem by dividing it into discrete reference rotational speeds and torque combinations. Instead of performing continuous complex simulations, the system pre-calculates and stores saturation temperatures for specific segmented operating points. During operation, the controller selects the appropriate segment based on current speed and torque, significantly reducing computational load while maintaining accuracy.
Solution Approach 2:
The patent performs preliminary calculation and storage of saturation temperature data for multiple reference rotational speeds and torque values before actual operation. This pre-computation allows the controller to quickly retrieve and use stored data during runtime without performing complex real-time simulations, achieving both accuracy and efficiency.
3Measurement precision
If contour line map of saturation temperature is used for temperature estimation, then temperature can be estimated without temperature sensor, but transitional temperature change cannot be estimated with good accuracy
Solution Approach 1:
The patent makes the temperature estimation dynamic by incorporating multiple reference rotational speeds and their corresponding saturation temperature characteristics. Instead of using a static contour line map, the system dynamically selects and combines data from multiple speed references based on the current operating point, allowing accurate tracking of transitional temperature changes as operating conditions vary.
Solution Approach 2:
The patent changes the estimation parameters by using multiple reference rotational speeds and their associated saturation temperature data instead of a single static map. The controller adjusts which reference data to use based on the relationship between current speed, torque, and the stored reference data, enabling accurate estimation of transitional behavior as parameters change.
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 approach enables accurate estimation of temperatures with reduced arithmetic load, allowing for timely detection of temperature changes and prevention of overheating, thus enhancing the reliability of AC rotary electric machines.
Implementation Method 1
the stator coil, the stator core, the rotor core and the like generate heat due to the copper loss
Implementation Method 2
the stator coil, the stator core, the rotor core and the like generate heat due to the copper loss, the iron loss
Implementation Method 3
When the temperature of the permanent magnet provided in the rotor rises, performance degradation, such as heat demagnetization, may occur
Data Source
AI summary
A controller for a rotary electric machine may include: at least one memory that stores a temperature prediction data in which a relationship among a rotational speed of a rotary electric machine, a torque information of the rotary electric machine, a temperature of the rotary electric machine at a reference time point, and a temperature of the rotary electric machine after an estimation calculation period elapses from the reference time point, and at least one processor that, at every estimation calculation period, sets the last calculation time before the estimation calculation period as the reference time point, and, by referring to the temperature prediction data, calculates an estimation value of temperature of the rotary electric machine after the estimation calculation period elapses from the last calculation time.