Vehicle AC Generator Magnetic-Field Current Control
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Solution Overview
Problem
Conventional vehicle AC generator control apparatuses struggle to accurately control rotation torque, leading to instability in internal combustion engine control and inefficient regenerative braking due to difficulties in instantaneous calculation of numerous parameters and limitations in output voltage control during regenerative braking.
Innovation Solution
A vehicle AC generator control apparatus with a magnetic-field current control system that controls the magnetic-field current based on a command value, allowing the rotation torque to depend solely on rotation speed, and includes a conversion unit to manage external commands and voltage control for stable operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional voltage control methods are used, then the control system is simple, but the rotation torque cannot be accurately controlled leading to engine instability
Solution Approach 1:
The patent changes the control parameter from output voltage to magnetic-field current. By controlling the magnetic-field current directly, the rotation torque of the AC generator can be accurately controlled, which stabilizes the internal combustion engine operation. This parameter change enables precise torque control without requiring complex multi-parameter calculations.
Solution Approach 2:
The patent replaces the conventional voltage-based electrical control system with a current-based control system. By using magnetic-field current control instead of voltage control, the system achieves more direct and accurate torque control, improving engine stability while maintaining reasonable system complexity.
2Measurement precision
If multiple parameters are calculated instantaneously, then accurate torque control is achieved, but the calculation burden becomes too high for real-time control
Solution Approach 1:
The patent extracts and controls only the essential parameter - magnetic-field current - that directly determines rotation torque. By focusing control on this single critical parameter rather than calculating multiple parameters simultaneously, the system achieves accurate torque control with reduced computational burden, enabling real-time control.
3Reliability
If output voltage is limited during regenerative braking, then battery protection is ensured, but regenerative braking efficiency is reduced
Solution Approach 1:
The patent changes the control approach from voltage limitation to current control during regenerative braking. By controlling the magnetic-field current, the system can optimize the balance between battery protection and energy recovery efficiency, allowing more effective regenerative braking while still protecting the battery from excessive voltage.
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 solution stabilizes internal combustion engine control, improves gasoline mileage, and enables effective regenerative braking by accurately managing rotation torque and output voltage, preventing engine stalling and ensuring stable power supply.
Implementation Method 1
a magnetic-field current control system which can control a value of a magnetic-field current flowing in a magnetic-field winding (3) of the vehicle AC generator (1)
Implementation Method 2
A rectifier 14 converts AC output power induced across an armature winding 13 into DC power and then supplies the DC power to a magnetic-field winding 3 and a high-capacitance capacitor 20
Data Source
Figure 1
Figure 2
Figure 3
AI summary
A vehicle AC generator control apparatus, the rotor of an vehicle AC generator 1 of which is coupled through a torque transfer member with the output axle of an internal combustion engine mounted in a vehicle, is provided with a magnetic-field current control system that can control the value c of a magnetic-field current flowing in a magnetic-field winding 3 of the vehicle AC generator 1 so that the magnetic-field current value c coincides with a magnetic-field current command value b; it is made possible to make the rotation torque of the vehicle AC generator 1 depend only on the rotation speed and to stabilize control of the internal combustion engine.