Hybrid Vehicle LDC Voltage Control for Urban Fuel Efficiency

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Solution Overview

Problem

Conventional methods for controlling the low-voltage DC-DC converter in hybrid vehicles fail to optimize fuel efficiency in urban areas due to high energy consumption, which is influenced by variable driving conditions such as traffic congestion and road gradients, leading to reduced fuel efficiency.

Innovation Solution

A method for controlling the battery state of charge (SOC) of a hybrid vehicle by determining driving load modes and adjusting the low-voltage DC-DC converter output voltage based on calibration values derived from vehicle speed and road inclination, using a differentiated strategy to balance the auxiliary battery SOC, thereby optimizing fuel efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If conventional control method is used to adjust LDC output voltage in variable driving load situations, then the system maintains basic functionality, but fuel efficiency in urban areas is reduced

Engineering Contradiction:

Improvefuel efficiencyVSAvoidLDC energy consumption

Core Design Contradiction:

Use of energy by moving objectVSLoss of energy

Solution Approach 1:

The patent implements dynamic LDC output voltage adjustment based on real-time driving conditions. The controller continuously monitors vehicle speed, acceleration, and driving mode to dynamically modify LDC output voltage, transitioning from fixed conventional control to adaptive dynamic control that optimizes energy conversion efficiency under varying load conditions

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The patent changes the operating parameters of the LDC by adjusting output voltage based on driving load mode. By categorizing driving conditions into different load modes and corresponding voltage ranges, the system modifies electrical parameters to match actual power demands, reducing energy loss during voltage conversion from the high-voltage battery to auxiliary loads

Inventive Principle:

Principle #35Parameter changes

2Power

If LDC output voltage is adjusted for high load mode, then power supply capability is improved, but auxiliary battery SOC balance is disrupted

Engineering Contradiction:

Improvepower supply capabilityVSAvoidauxiliary battery SOC balance

Core Design Contradiction:

PowerVSReliability

Solution Approach 1:

The patent incorporates feedback control by continuously monitoring auxiliary battery SOC levels and using this information to adjust LDC output voltage. When auxiliary battery charge levels are detected, the controller reduces LDC output voltage to prevent overcharging, creating a closed-loop control system that maintains SOC balance while still providing adequate power supply capability

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The system dynamically adjusts LDC output voltage not only based on power demand but also based on auxiliary battery charge state. This dual-dynamic adjustment allows the system to modulate power transfer in real-time, balancing immediate power supply needs with long-term battery health and charge balance

Inventive Principle:

Principle #15Dynamics

3Loss of energy

If LDC output voltage is reduced to save energy, then energy consumption is decreased, but power supply to electric field loads is insufficient

Engineering Contradiction:

ImproveLDC energy consumptionVSAvoidpower supply to electric field loads

Core Design Contradiction:

Loss of energyVSPower

Solution Approach 1:

The patent applies parameter changes by establishing multiple LDC output voltage ranges corresponding to different driving load modes. Rather than uniformly reducing voltage, the system selectively adjusts voltage parameters to match actual load requirements, ensuring sufficient power delivery during high-demand conditions while reducing consumption during low-demand periods

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent segments the driving operation into different load modes (high load mode and low load mode) with distinct voltage control strategies. This segmentation allows the system to apply appropriate voltage levels for each operational context, preventing both energy waste during light loads and power deficiency during heavy loads

Inventive Principle:

Principle #1Segmentation

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 improves fuel efficiency in urban areas by reducing electric field load power consumption, maintaining optimal auxiliary battery SOC levels, and minimizing energy loss, thereby enhancing overall fuel efficiency and commercial value.

Implementation Method 1

a low-voltage direct current-direct current (DC-DC) converter (LDC) installed in a hybrid vehicle is configured to charge an auxiliary battery by converting a high DC voltage output from a main battery into a low DC voltage

Methodology Applied

Scientific EffectElectrical energy conversion: Electromagnetic Induction

Data Source

PatentUS9849804B2Method and system for controlling battery SOC of hybrid vehicle

Publication Date: 2017.12.26 HYUNDAI MOTOR CO LTD

AI summary

A method and system for controlling a battery SOC of a hybrid vehicle are provided to improve fuel efficiency in an urban area with a differentiated strategy for controlling auxiliary battery SOC balance of the hybrid vehicle. The method improves fuel efficiency in urban areas with a differentiated strategy of controlling SOC balance of an auxiliary battery considering that the degree of influence of electric field load consumption on fuel efficiency based on LDC voltage adjustment in the hybrid vehicle varies based on driving mode and road gradient.