Dual Alternator System LIN Bus Control Strategy
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Solution Overview
Problem
In dual alternator systems, existing control strategies can introduce instability due to competing control loops from separate voltage regulators operating at different rates, which can affect the smooth operation and efficiency of alternators with different current ratings.
Innovation Solution
A control strategy that uses a LIN bus to manage a secondary alternator with a LIN-controlled voltage regulator, employing a maximum excitation current limit (MECL) setpoint and voltage setpoints above nominal system voltage to stabilize the system, allowing the main alternator to operate under conventional voltage regulation while the secondary alternator provides additional current as needed, thereby preventing instability and optimizing load modes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If separate voltage regulators control each alternator independently, then each alternator can be regulated individually, but system instability occurs due to competing control loops operating at different rates
Solution Approach 1:
The patent merges the control of both alternators under a single master voltage regulator that coordinates their operation. The master regulator monitors system voltage and controls the primary alternator, while the secondary alternator is controlled only when additional current is needed, eliminating competing control loops and achieving both individual regulation capability and system stability.
Solution Approach 2:
The patent introduces a control strategy that acts as an intermediary between the two alternators. The master voltage regulator serves as the mediator that decides when the secondary alternator should engage based on system conditions, preventing direct competition between regulators while maintaining individual control capability.
2Quantity of substance
If a dual alternator system is implemented to provide high current output, then battery life and state of charge are preserved, but control complexity increases due to coordinating two alternators with different current ratings
Solution Approach 1:
The patent segments the control function into two levels: a master voltage regulator that handles overall system voltage control and alternator engagement decisions, and a secondary alternator controller that executes specific control actions only when needed. This segmentation reduces control complexity by dividing responsibilities based on the different current ratings of the alternators.
Solution Approach 2:
The patent changes the operational parameters of the secondary alternator dynamically - it remains inactive during normal operation and engages only when system current demand exceeds the primary alternator's capacity. This parameter-based control approach simplifies the overall control strategy by using clear threshold-based decision-making.
3Stability of the object's composition
If the secondary alternator is controlled with a voltage setpoint above nominal system voltage, then system stability is improved by preventing control loop competition, but the risk of overvoltage conditions increases
Solution Approach 1:
The patent implements feedback control where the master voltage regulator continuously monitors system voltage and only engages the secondary alternator when additional current is genuinely needed. The secondary alternator's voltage setpoint is managed through feedback from the master regulator, ensuring that overvoltage conditions are prevented while maintaining stability by coordinating the high-voltage setpoint with actual system demands.
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 approach ensures stable operation of dual alternators by preventing competition between control loops, allowing for efficient current provision and minimizing system instability, while also enabling easy integration with existing alternator architectures.
Implementation Method 1
the external voltage regulator outputs a pulse width modulated drive signal to the field winding of the alternator and varies field voltage of the alternator to regulate the output voltage of the alternator by varying the duty cycle of the pulse width modulated signal
Implementation Method 2
A voltage regulator is used to regulate the output voltage of the alternator. Typically, the voltage regulator varies the voltage of the field of the alternator to regulate the output voltage of the alternator.
Data Source
AI summary
A dual alternator system includes a main alternator controlled by an electronic voltage regulator, a secondary alternator system having a secondary alternator controlled by a LIN controlled alternator voltage regulator and an electronic control unit (“ECU”) coupled to the LIN controller alternator voltage regulator by a LIN bus that that determines whether the secondary alternator should be off or operated to generate current. The ECU when it determines that the secondary alternator should be off sends a voltage setpoint signal to the LIN controlled alternator voltage regulator having a low value that is well below nominal system voltage. The ECU when it determines that the secondary alternator should be operated to provide current sends a voltage setpoint to the LIN controlled alternator voltage regulator having a high value that is well above a nominal system voltage and a MECL setpoint value.