LDC Voltage Control for Hybrid Vehicle Battery Durability
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Solution Overview
Problem
The existing voltage control methods for Low Voltage Direct Current (LDC) converters in hybrid vehicles frequently change output voltage based on driving modes without considering the charged status of the auxiliary battery, leading to decreased lifespan, durability, and inefficient fuel consumption.
Innovation Solution
The method involves determining LDC output voltage control modes for primary three driving modes (EV, engine charge, and regenerative braking) and separating high electric loads into groups, using Intelligent Battery Sensor (IBS) information to generate a voltage order table based on battery state of charge (SOC) and temperature, prioritizing voltage for high and low loads to minimize energy consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the LDC voltage control mode is determined for seven different driving conditions, then the voltage control adapts to various driving scenarios, but the frequent changes of LDC output voltage order occur as the driving mode changes, decreasing the lifespan and durability of the LDC
Solution Approach 1:
The patent segments the seven driving conditions into three main driving modes (EV mode, engine charge mode, and regenerative braking mode). This segmentation reduces the frequency of voltage control mode changes while maintaining adaptability to different driving scenarios, thereby resolving the contradiction between voltage control adaptability and LDC durability.
2Ease of operation
If the LDC output voltage is frequently adjusted based on driving mode changes, then the voltage control responds to driving conditions, but the LDC power consumption increases and fuel efficiency deteriorates
Solution Approach 1:
The patent implements dynamic voltage adjustment within each driving mode based on the charge status of the auxiliary battery. The LDC output voltage is adjusted dynamically according to battery SOC (State of Charge) levels, allowing responsive voltage control while minimizing unnecessary frequency changes, thus reducing LDC power consumption and improving fuel efficiency.
3Device complexity
If the voltage control does not consider the charge status of the auxiliary battery, then the control logic is simpler, but the charge efficiency of the auxiliary battery decreases and fuel efficiency improvement becomes difficult
Solution Approach 1:
The patent introduces feedback control by continuously monitoring the charge status (SOC) of the auxiliary battery and adjusting the LDC output voltage accordingly. This feedback mechanism ensures optimal charging efficiency while maintaining manageable control logic through the structured three-mode framework, resolving the contradiction between control simplicity and charging efficiency.
Data Source
AI summary
A method and system are provided for variably adjusted voltage of the LDC applied with an IBS (Intelligent Battery Sensor). The LDC output voltage control mode is determined in each of three driving modes, and the high electric loads are separated into two or more groups. The LDC output voltage value and the order priority are differentiated based on the durability of the auxiliary battery. Additionally, an LDC output voltage order table is generated according to the driving mode and the SOC state based on the auxiliary battery SOC information obtained from an IBS. Thus, consumed energy of the LDC and an energy consumption amount of the auxiliary battery are minimized, thus improving fuel efficiency.