Excitation Current-Limited Power Generator for Vehicle Alternators
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Power generators, such as alternators in vehicles, experience degraded performance at lower engine speeds and cold temperatures, leading to excessive output and counter-torque, which can damage the generator over time.
Innovation Solution
An excitation current-limited power generator system that includes a digital interface with an engine control unit, a regulator, and a frequency sensor, which limits the excitation current to prevent excessive output and counter-torque by using permanent and communicated limits based on rotation speed thresholds.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the excitation current is increased to maintain power output at lower engine speeds, then the power generation capability is improved, but the counter-torque on the combustion engine increases and may exceed maximum rated output
Solution Approach 1:
The patent applies dynamics by making the excitation current limit adjustable and adaptive rather than fixed. The system dynamically adjusts the excitation current ceiling based on real-time engine speed feedback and operating conditions, allowing optimal power output at each speed point while preventing excessive counter-torque. This is achieved through a control system that continuously monitors engine speed and modifies the maximum permitted excitation current accordingly.
Solution Approach 2:
The patent changes the parameter of excitation current from a fixed value to a variable parameter that depends on engine speed and operating conditions. By establishing a relationship between engine speed and maximum permitted excitation current, the system optimizes power generation across different operating ranges while preventing damage from excessive torque at low speeds.
2Reliability
If the excitation current is limited to prevent excessive output and counter-torque, then the generator is protected from damage, but the power output may be insufficient to meet vehicle electrical demands
Solution Approach 1:
The system dynamically adjusts the excitation current limit based on real-time monitoring of engine speed and electrical system demands. Rather than using a static conservative limit, the control system continuously adapts the maximum permitted excitation current to match actual operating conditions, ensuring both generator protection and adequate power output.
Solution Approach 2:
The patent implements feedback control by monitoring engine speed and electrical system requirements, then using this information to adjust the excitation current limit. The system receives feedback about actual operating conditions and modifies the excitation current ceiling accordingly, balancing protection needs with power delivery requirements.
3Power
If the excitation current is increased to meet electrical demands, then the power output is sufficient, but the generator may exceed maximum rated output and suffer degraded performance
Solution Approach 1:
The patent applies preliminary action by pre-establishing maximum permitted excitation current limits based on engine speed and generator capabilities before excessive output conditions occur. The control system proactively prevents the excitation current from reaching levels that would cause degraded performance or damage, rather than reacting after the problem occurs.
Solution Approach 2:
The system provides beforehand cushioning by implementing a safety margin through the maximum permitted excitation current limit. This pre-established protective barrier prevents the generator from operating in conditions that would lead to degraded performance or damage, cushioning against potential failures before they occur.
4Device complexity
If a fixed excitation current limit is used to simplify control, then the device complexity is reduced, but the system cannot adapt to varying engine speeds and operating conditions
Solution Approach 1:
The patent resolves this contradiction by implementing a dynamic control system that adjusts the excitation current limit based on engine speed and operating conditions. Rather than using a simple fixed limit, the system continuously adapts the maximum permitted excitation current to match actual operating requirements, achieving both adaptability and reasonable complexity through modern electronic control.
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 allows the generator to operate safely in harsh conditions, preventing damage and improving efficiency, reliability, and lifespan of fuel-efficient vehicles by limiting current output and torque production.
Implementation Method 1
Power generators typically include a rotating coil in stator coils. The output current of stator coils may be controlled by changing an excitation current flowing through the rotating coil.
Data Source
AI summary
An excitation current-limited power generator includes a digital interface configured to be coupled to an engine control unit (ECU), a regulator coupled configured to be coupled to an excitation current input of an alternator, the excitation current controlling current generated by the alternator, a frequency sensor configured to measuring rotation speed of the alternator, and memory storing a communicated limit received by the digital interface and a first permanent limit, the regulator configured to limit the excitation current to the lesser of the first permanent limit and the communicated limit.