Alternator Control Device Thermal Management
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Solution Overview
Problem
High-power motor vehicle alternators face thermal imbalance issues due to increased current and voltage, leading to excessive losses and potential machine destruction when operating at overspeed, as existing solutions fail to effectively manage thermal stability.
Innovation Solution
A control device that integrates a servo loop for voltage regulation and a temperature servo loop to manage excitation current and temperature, using sensors to monitor component temperatures and adjust excitation percentage to maintain temperatures below a maximum threshold, thereby preventing thermal overload.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the excitation current is increased to boost alternator output performance, then the power delivery capability is improved, but the thermal losses (Joule losses and iron losses) increase correlatively
Solution Approach 1:
The patent implements a temperature feedback control system where temperature sensors continuously monitor the alternator's temperature, and the control unit adjusts the excitation current accordingly. When temperature reaches a predetermined threshold, the control unit reduces or stops increasing the excitation current, preventing excessive thermal losses while maintaining optimal power output.
Solution Approach 2:
The patent dynamically changes the excitation current parameter based on temperature conditions. By adjusting this electrical parameter in response to thermal feedback, the system optimizes the balance between power output and thermal losses, preventing energy waste while maintaining alternator performance within safe thermal limits.
2Power
If the excitation current is increased to temporarily boost alternator throughput, then the power delivery is improved, but the alternator temperature exceeds the maximum admissible temperature
Solution Approach 1:
The control system uses temperature feedback from sensors positioned at critical locations within the alternator. When the measured temperature approaches the maximum admissible temperature, the control unit automatically adjusts the excitation current to prevent overheating, thereby maintaining power delivery within safe thermal boundaries.
Solution Approach 2:
The patent employs dynamic control of the excitation current based on real-time temperature conditions. Rather than using a fixed excitation level, the system continuously adapts the excitation current parameter according to the alternator's thermal state, enabling temporary power boosts when cool and preventing overheating when temperature rises.
3Power
If the nominal network voltage is increased to 42 V to provide higher power, then the power delivery capability is improved, but the thermal balance of the machine deteriorates
Solution Approach 1:
The patent implements dynamic adjustment of multiple operating parameters including excitation current and voltage levels based on temperature feedback. When operating at elevated voltages such as 42 V, the control system monitors temperature and adjusts the excitation current to maintain thermal balance, preventing the deterioration of thermal conditions that would otherwise occur at higher power levels.
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 control device effectively maintains alternator component temperatures within safe limits, preventing thermal damage and ensuring reliable operation by adjusting excitation current based on real-time temperature feedback, thus enhancing thermal stability and extending alternator lifespan.
Implementation Method 1
at least one temperature sensor providing at least one current component temperature
Implementation Method 2
a semiconductor switch driven by the pulse width modulated signal controlling the intensity of the excitation current
Implementation Method 3
slaving a DC voltage generated by this alternator to a predetermined voltage setpoint
Implementation Method 4
an excitation circuit comprising an excitation winding of a rotor of the alternator
Data Source
Figure 1a~1b
Figure 2
Figure 3a~3b
AI summary
The invention relates to a device for controlling an alternator of the type that controls a DC voltage (B+A) generated by the alternator (11) according to a predetermined set voltage (U0) by monitoring the intensity of an energising current (IEXC) flowing through an energising circuit of the alternator. According to the invention, the device includes a voltage-control loop (7) and a temperature-control loop (17) which comprises a temperature sensor supplying a current temperature (T) of components of the alternator, a subtracter (19) supplying a temperature error (ετ) between the current temperature (T) and a maximum acceptable temperature (Tmax) and a control module (20) supplying a maximum admissible energising percentage (rmax) in accordance with the temperature error according to a predetermined control law.