Field Winding Rotary Machine Current Integration Control
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Solution Overview
Problem
Existing rotary electric machines for vehicles face temperature-related damage due to high operating temperatures, particularly during continuous operation, and existing solutions that rely on temperature sensors are costly and ineffective when the initial temperature condition is unknown, such as at startup.
Innovation Solution
A field winding type rotary electric machine with a controller that integrates excessive field current and limits it to prevent excessive temperature rise, eliminating the need for a temperature sensor by using a field current integration and limiting mechanism, along with a controller power supply connection switch to maintain power feeding during limiting processing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a temperature sensor is incorporated to protect the AC generator against temperature rise, then the reliability of temperature monitoring is improved, but the cost and structural complexity increase
Solution Approach 1:
The system uses the field current information already available in the control apparatus to self-diagnose temperature conditions. The field current integration portion calculates an integral value that correlates with temperature rise, eliminating the need for external temperature sensors while maintaining monitoring capability through existing system resources
Solution Approach 2:
The patent introduces an integral value as an intermediary parameter that mediates between field current and temperature. This integral value serves as a proxy indicator of temperature conditions, allowing the system to infer temperature status without direct measurement, thus avoiding the need for temperature sensors
2Temperature
If field current is limited based on temperature sensor detection, then temperature rise is prevented, but the response is delayed when initial temperature is unknown at startup
Solution Approach 1:
The system performs preliminary assessment of temperature conditions by calculating the integral value of field current from startup. This preliminary calculation continues in the background even before field current limiting is activated, so when temperature conditions require intervention, the system already has accumulated data to make immediate decisions without delay
Solution Approach 2:
The system continuously calculates the integral value of field current and uses this feedback to determine when field current limiting should be activated. This continuous feedback mechanism ensures the system responds immediately when temperature conditions exceed thresholds, eliminating the response delay present in sensor-based systems that wait for startup completion
3Ease of manufacture
If field current limiting is implemented without temperature sensor, then cost is reduced, but the ability to detect actual temperature conditions is weakened
Solution Approach 1:
The system creates a computational copy of temperature information by calculating the integral value of field current. This integral value replicates the temperature indication function without requiring physical temperature sensors, thereby reducing manufacturing cost while maintaining the capability to detect and respond to temperature conditions through mathematical modeling of the thermal behavior
Data Source
AI summary
A field winding type rotary electric machine includes: a controller; a field current integration portion provided in the controller to calculate an integral value by integrating an excessive field current exceeding a field current threshold; a field current limiting portion provided in the controller and carrying out limiting processing to limit a field current to or below a predetermined value when the integral value reaches an integral value threshold defined as a reference value at or above which the field current is limited; a controller power supply connection switch switched ON and OFF for power feeding to the controller; a controller power supply connection determination portion switching ON and OFF the controller power supply connection switch; and a power feeding ON state maintaining portion maintaining an ON state of the power feeding to the controller from start to end of the limiting processing by the field current limiting portion.