Alternator-Starter Torque Control for Voltage Drop Mitigation
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Solution Overview
Problem
High currents required by alternate starters in motor vehicles during startup lead to significant voltage drops, affecting the power supply to essential equipment like headlamps, radios, airbags, and power steering, compromising user comfort and safety.
Innovation Solution
A method and system for controlling an alternator-starter in motor vehicles that involves an inverter powered by an edge electrical network, where the inverter is controlled based on a motor torque setpoint, with voltage monitoring and comparison to predetermined thresholds, and torque reduction strategies to mitigate voltage drops, including pulse width modulation and excitation current management.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If high current is supplied to the alternator-starter to achieve required boot torque, then the motor torque is improved, but the voltage drop at the battery increases
Solution Approach 1:
The patent implements dynamic control of the alternator-starter by continuously monitoring battery voltage and adjusting the motor torque setpoint in real-time. The control module modifies operational parameters based on voltage conditions, transitioning from static high-torque operation to dynamic adaptive operation that maintains performance while preventing excessive voltage drops.
Solution Approach 2:
The patent changes operational parameters by adjusting the motor torque setpoint based on battery voltage levels. When voltage drops below thresholds, the system reduces torque demand and modifies inverter control parameters. This parameter adaptation allows the system to operate efficiently across varying battery conditions without compromising safety or performance.
2Power
If high current is supplied to the alternator-starter during startup, then the boot torque is improved, but the power supply to other equipment is compromised
Solution Approach 1:
The patent employs feedback control by continuously monitoring battery voltage and using this information to adjust alternator-starter operation. The control module receives voltage feedback, compares it to predefined thresholds, and automatically adjusts torque setpoints and inverter parameters to maintain voltage within acceptable ranges, ensuring reliable power supply to critical equipment during startup.
Solution Approach 2:
The system dynamically adjusts its operation based on real-time voltage conditions, transitioning from fixed high-torque startup to adaptive operation that prioritizes both motor performance and electrical system stability. This dynamic behavior ensures critical equipment receives adequate power while still achieving necessary boot torque.
3Use of energy by moving object
If the engine is restarted while the vehicle is running to reduce energy consumption, then fuel efficiency is improved, but voltage drops can lead to insufficient power supply of safety equipment
Solution Approach 1:
During engine restart operations, the system continuously monitors battery voltage and adjusts alternator-starter torque output based on real-time voltage feedback. This feedback control ensures that restart operations do not cause voltage drops that would compromise safety equipment, while still achieving the energy-saving benefits of stop-start operation.
Solution Approach 2:
The patent applies preliminary anti-action by proactively reducing alternator-starter torque demand when voltage thresholds are approached, before critical voltage drops occur. This preventive approach ensures safety equipment remains properly powered by anticipating and counteracting potential voltage insufficiencies before they affect system reliability.
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 limits voltage drops during startup, ensuring reliable power supply to critical safety and comfort systems, thereby enhancing user safety and comfort by dynamically adjusting torque setpoints based on voltage conditions.
Implementation Method 1
an inverter powered by an onboard electrical network for operation in starter mode
Implementation Method 2
the rotor electromagnets are controlled by an excitation current to produce a rotor field
Implementation Method 3
the voltage at the terminals of the inverter being calculated taking into account the resistance of the cables
Data Source
Figure 1~2
Figure 3~4
AI summary
The present invention relates to a method of controlling an alternator-starter (1) of a motor vehicle in starter mode, said alternator-starter (1) comprising an inverter (3) powered by an on-board electrical network (7), said method comprising the following steps: - the inverter (3) is controlled according to a motor torque setpoint, - the voltage across the inverter (3) is determined, - the voltage across the inverter (3) is compared to a predetermined voltage threshold, if the voltage across the inverter (3) is less than the predetermined voltage threshold, - the motor torque setpoint is reduced.