Vehicle Voltage Control System Dynamic Load Management
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Solution Overview
Problem
The high energy consumption of low-voltage electrical systems in electrified vehicles, particularly due to inefficient voltage management, leads to significant fuel consumption and potential offset of fuel economy improvements in high-voltage powertrains, with unnecessary voltage increases degrading fuel economy and causing variability in dynamometer test results.
Innovation Solution
A vehicle voltage control system that includes a power converter and a controller to manage the output voltage of the low-voltage bus, setting it to a maximum of target voltages for active electrical loads, a charging voltage when the auxiliary battery needs charging, and a float voltage to minimize energy consumption and prevent micro-cycling, thereby optimizing energy use and reducing fuel consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the output voltage of the power converter is continuously increased to meet the demands of all possible electrical loads, then the voltage availability for electrical loads is improved, but the fuel consumption increases and energy efficiency deteriorates
Solution Approach 1:
The patent implements dynamic voltage control by continuously monitoring the activation states of electrical loads and adjusting the power converter output voltage in real-time. The controller dynamically selects from multiple voltage levels (e.g., 14V, 13V, 12V) based on current system demands, rather than maintaining a fixed high voltage. This dynamic adaptation resolves the contradiction by providing voltage availability only when and where needed, eliminating continuous energy waste.
Solution Approach 2:
The system changes the voltage parameter of the power converter output based on operational conditions. By implementing multiple discrete voltage levels and selecting the appropriate level according to load requirements and battery state of charge, the system optimizes energy efficiency while maintaining adequate voltage supply. This parameter adjustment resolves the contradiction between voltage availability and fuel consumption.
2Power
If the output voltage is increased to ensure adequate power supply to electrical loads, then the power delivery capability is improved, but the energy consumption of the low-voltage system increases
Solution Approach 1:
The system dynamically adjusts voltage levels based on actual power demands of activated loads. By monitoring which electrical loads are active and calculating the minimum required voltage to satisfy their power requirements, the controller delivers adequate power only at the necessary voltage level, minimizing energy losses in the low-voltage system.
Solution Approach 2:
The system applies partial action by providing voltage increases only to the extent necessary to meet current load demands, rather than continuously maintaining maximum voltage. The controller calculates the minimum voltage required and applies only that level, avoiding excessive voltage application that would cause unnecessary energy consumption and heat losses.
3Quantity of substance
If the auxiliary battery is continuously charged at high voltage, then the battery state of charge is improved, but the battery lifespan decreases due to increased charging cycles
Solution Approach 1:
The system implements periodic charging actions rather than continuous charging. The controller monitors battery state of charge and only activates charging when the battery falls below a threshold level. This periodic charging approach maintains adequate battery charge levels while minimizing the number of charging cycles, thereby extending battery lifespan.
Solution Approach 2:
The system changes the charging voltage parameter based on battery state of charge and operational conditions. By adjusting the charging voltage level and duration according to actual battery needs rather than continuously applying high voltage charging, the system maintains battery health while ensuring adequate charge levels are achieved.
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 system effectively reduces fuel consumption by optimizing low-voltage electrical system energy use, maintaining consistent performance of voltage-sensitive loads, and extending battery life by minimizing unnecessary charging and discharging cycles.
Implementation Method 1
a power converter electrically coupled to an auxiliary battery and an electrical load
Data Source
AI summary
A vehicle includes a power converter electrically coupled to an auxiliary battery and an electrical load. A vehicle voltage control system includes a controller programmed command an output voltage of the power converter to a voltage that is a maximum of target voltages associated with electrical loads that are electrically coupled to the auxiliary battery and activated, a battery charging voltage when a demand for auxiliary battery charging is present, and a float voltage associated with the auxiliary battery.