Automotive Alternator Temperature Detection via Duty Cycle Feedback
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Solution Overview
Problem
Existing control apparatuses for electric generators face challenges in accurately determining the temperature of each component, leading to potential overheating and increased manufacturing costs due to reliance on ambient air temperature and rotational speed, with limitations in handling transient states and accurate determination of driving torque and output current.
Innovation Solution
An integrated electric generator temperature detecting device within the control apparatus, including a temperature detector, rotational speed detector, exciting current detector, and determiner, which uses specific operation parameters to accurately determine static and transient temperatures, and includes a power output limiter to prevent overheating, while reducing manufacturing costs by eliminating the need for additional sensors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the duty of intermittent exciting current supply is used instead of exciting current, then the device complexity is reduced, but the measurement precision of temperature determination deteriorates
Solution Approach 1:
The patent introduces a feedback mechanism where the control apparatus temperature detector continuously monitors the temperature and feeds this information back to the temperature determiner. This allows the system to dynamically adjust the exciting current duty cycle based on real-time temperature conditions, resolving the contradiction by maintaining measurement precision through continuous feedback while using duty cycle control.
Solution Approach 2:
The patent changes the parameter used for temperature determination from direct exciting current measurement to a combination of control apparatus temperature detection and duty cycle calculation. By detecting the control apparatus temperature directly and using the duty cycle as a control parameter rather than a measurement parameter, the system achieves both reduced complexity and maintained precision.
2Measurement precision
If additional sensors are included to accurately detect parameters, then the measurement precision is improved, but the manufacturing cost increases
Solution Approach 1:
The patent makes the control apparatus temperature detector serve multiple functions: it detects the control apparatus temperature directly, provides data for ambient temperature determination, and enables calculation of exciting current parameters. This multi-functionality eliminates the need for separate sensors for each parameter, achieving high measurement precision without increasing manufacturing cost through additional components.
Solution Approach 2:
The control apparatus uses its own temperature detection capability to serve the dual purpose of monitoring its operational state and determining the temperature characteristics of the electric generator. The system essentially uses itself as the sensing element, eliminating the need for external sensors and reducing manufacturing costs while maintaining measurement precision.
3Device complexity
If the control apparatus temperature is used to determine ambient air temperature, then the measurement precision deteriorates during transient states, but the device complexity is reduced
Solution Approach 1:
The patent introduces dynamic response characteristics by incorporating a time constant into the ambient temperature determination process. The temperature determiner uses a dynamic model that accounts for the thermal inertia and time delays between control apparatus temperature changes and actual ambient temperature changes. This dynamic approach maintains measurement precision during transient states while keeping the device complexity low by using a mathematical model rather than additional hardware.
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
The solution enables precise temperature detection and control of electric generator components, preventing overheating and accurately determining driving torque and output current, thereby enhancing the reliability and efficiency of the electric generator while reducing costs.
Implementation Method 1
a control apparatus temperature detector that detects a temperature of a control apparatus
Implementation Method 2
a rotational speed detector that detects a rotational speed of the electric generator
Implementation Method 3
an exciting current detector that detects an exciting current supplied to the exciting winding
Implementation Method 4
determining a temperature of each component of the electric generator based on the control apparatus temperature, the rotational speed, and the exciting current
Data Source
AI summary
A control apparatus for a vehicle generator includes a switch, a regulator, a fault condition detector, and a PWM signal generator. The switch is selectively turned on and off so as to intermittently excite the generator. The regulator controls on/off operation of the switch so as to bring an output of the generator into agreement with a target value. The fault condition detector detects a fault condition of the generator. The PWM signal generator generates and outputs a PWM signal that has a duty determined as a function of a duty of the on/off operation of the switch and a frequency determined based on if the fault condition of the generator is detected by the fault condition detector. Consequently, the control apparatus can inform an external control apparatus of the duty of the on/off operation of the switch and the fault condition of the generator with the single PWM signal.