Vehicle AC Generator Control Device for Drive Torque Suppression
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional control devices for vehicle AC generators cannot suppress drive torque in accordance with RPM, leading to inefficiencies in energy use and increased magnetic sound.
Innovation Solution
A control device for a vehicle AC generator that includes a power transistor, an RPM detection section, and a drive duty setting section to adjust the conduction ratio of the field coil based on detected RPM, reducing drive torque and improving energy efficiency while minimizing magnetic sound.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the conduction ratio of the field coil is maintained at high levels to ensure sufficient electric power output, then the generator can meet power demands, but drive torque increases excessively and energy efficiency deteriorates
Solution Approach 1:
The patent applies dynamics by making the field coil conduction ratio variable rather than fixed. The control device dynamically adjusts the conduction ratio based on real-time RPM detection, switching between high conduction ratio at low RPM and reduced conduction ratio at high RPM, thereby optimizing the balance between power output and energy efficiency across different operating conditions
Solution Approach 2:
The patent changes the operational parameters of the field coil by adjusting its conduction ratio according to RPM. At high RPM, the conduction ratio is reduced to decrease drive torque and improve energy efficiency, while at low RPM, the conduction ratio is maintained or increased to ensure sufficient power output, thus using parameter changes to resolve the contradiction
2Power
If the field current is increased to enhance electric power generation, then the power output improves, but magnetic sound increases
Solution Approach 1:
The patent uses dynamic control of field current through the power transistor, adjusting the conduction ratio based on RPM detection. At high RPM where magnetic sound becomes problematic, the system dynamically reduces the field current by lowering the conduction ratio, thereby suppressing magnetic sound while maintaining adequate power generation capability
Solution Approach 2:
The system takes preliminary anti-action by detecting RPM and proactively reducing the field coil conduction ratio before magnetic sound becomes excessive. The control device anticipates the increase in magnetic sound at high RPM and preemptively adjusts the field current to prevent the harmful effect while maintaining power output
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 effectively suppresses drive torque and enhances energy efficiency by controlling the field current based on RPM, reducing excess electric power generation and magnetic noise.
Implementation Method 1
a power transistor (502) for controlling conduction/non-conduction of a field coil (3) in accordance with an output voltage of an AC generator (1)
Implementation Method 2
an RPM detection section (511) for detecting an RPM of the AC generator (1)
Implementation Method 3
a drive duty setting section (510) for determining whether or not the RPM detected by the RPM detection section (511) is equal to or higher than a predetermined threshold, and reducing a conduction ratio of the field coil (3)
Data Source
AI summary
The control device including: a power transistor (502) for controlling conduction/non-conduction of a field coil (3) in accordance with an output voltage of an AC generator (1) mounted on a vehicle; an RPM detection section (511) for detecting an RPM of the AC generator (1); a drive duty setting section (510) for determining whether or not the RPM detected by the RPM detection section (511) is equal to or higher than a predetermined threshold, and reducing a conduction ratio of the field coil (3) when determining that the RPM is equal to or higher than the predetermined threshold; and a driver (504) for driving the power transistor (502) based on the conduction ratio. In this manner, the conduction ratio of the field coil (3) is reduced to suppress the drive torque.