Rotary Electric Machine Control for Relay and Coil Temperature
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Solution Overview
Problem
Existing rotary electric machine control systems face challenges in accurately estimating temperature across multiple systems, leading to excessive current limitation and insufficient motor performance due to large temperature change estimates under varying drive conditions.
Innovation Solution
A rotary electric machine control apparatus that includes temperature detection and estimation sections to accurately estimate temperatures of power supply relays and a choke coil, coupled with current limit calculation and selection sections to dynamically adjust current limiting values based on the operation of multiple systems, thereby avoiding excessive current limitation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If temperature estimation is performed for multiple systems using a single system model, then the device complexity is reduced, but the temperature estimation accuracy deteriorates leading to excessive current limitation
Solution Approach 1:
The patent divides the temperature estimation into separate calculations for each system (first system and second system). The temperature estimation section calculates a first temperature estimation value for the first system and a second temperature estimation value for the second system independently, rather than using a single aggregated model. This segmentation allows each system's temperature to be estimated accurately based on its specific operating conditions, resolving the contradiction between simplicity and accuracy.
2Reliability
If current limitation is applied based on conservative temperature estimates, then the reliability of the system is improved, but the motor performance deteriorates due to excessive current limitation
Solution Approach 1:
The patent implements dynamic current limitation by selecting different current limitation values based on real-time temperature estimation results. The selection section chooses between a first current limitation value and a second current limitation value depending on which system has the higher temperature estimation. This dynamic adjustment allows the system to maintain reliability by limiting current only when necessary while maximizing motor performance when temperature conditions permit.
Solution Approach 2:
The patent changes the current limitation parameter dynamically based on temperature estimation. Instead of using a fixed conservative current limit, the system adjusts the current limitation value according to the estimated temperatures of the power supply relays and choke coils. This parameter change enables the system to achieve both reliability and optimal motor performance by adapting the current limit to actual thermal conditions.
3Measurement precision
If temperature change amount is added to sensor value for temperature estimation, then the temperature estimation accuracy is improved, but the current limitation becomes excessive when multiple systems are operated
Solution Approach 1:
The patent segments the temperature estimation calculation to account for each system's individual temperature change amount. Instead of summing or aggregating temperature changes from multiple systems (which would overestimate the total temperature), the system calculates temperature estimation values separately for each system based on their respective temperature change amounts and sensor readings. This segmentation prevents excessive current limitation while maintaining accurate temperature estimation for each system.
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
Improves temperature estimation accuracy for multiple systems, preventing excessive current limitation and ensuring sufficient motor performance by dynamically adjusting current limiting values based on system operation.
Implementation Method 1
a heatsink that releases heat of the switching elements
Implementation Method 2
a heatsink that releases heat of the switching elements
Implementation Method 3
a temperature detection section that detects a temperature of the substrate, a temperature of the heatsink, or an outside air temperature
Data Source
AI summary
In a rotary electrical machine control apparatus, a selection section selects a relay current limiting value or a coil current limiting value depending on whether a plurality of systems are operated or one or more but not all of the plurality of systems are operated. The system is a combination of a winding set, an inverter, and a power supply relay, which correspond to each other. The relay current limiting value is a current limiting value calculated based on the temperature of the power supply relay. The coil current limiting value is a current limiting value calculated based on the temperature of a choke coil.