Vehicle Control Device for Auxiliary Load Reliability
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Solution Overview
Problem
The existing power supply device for vehicles does not consider the timing of driving the DC-to-DC converter and the auxiliary load, leading to potential failure in driving the auxiliary load when the auxiliary battery is in a state that cannot supply the required electric power, especially when the start switch is off and a user is presumed to be in the vehicle.
Innovation Solution
A vehicle control device that includes a processor to determine the state of the start switch and the boarding state, acquiring the voltage of the secondary battery, and controlling the order in which the DC-to-DC converter and the auxiliary load are driven based on the battery's state of charge and internal resistance, ensuring reliable operation of the auxiliary load by prioritizing the DC-to-DC converter's operation when the battery's state is insufficient.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the auxiliary load is driven before the DC-to-DC converter when the auxiliary battery cannot supply required power, then the auxiliary load operation is delayed or failed, but the system complexity and control logic remain simple
Solution Approach 1:
The control device determines the state of charge of the auxiliary battery in advance before the auxiliary load starts operating. Based on this preliminary assessment, the control device pre-determines the optimal driving sequence, either driving the auxiliary load first or first driving the DC-to-DC converter to charge the auxiliary battery. This preliminary action ensures that the auxiliary load can reliably operate without interruption while maintaining relatively simple control logic.
Solution Approach 2:
The control device continuously monitors the state of charge of the auxiliary battery and uses this feedback information to dynamically adjust the driving sequence of the auxiliary load and DC-to-DC converter. When the state of charge is insufficient, the system feedback triggers a sequence where the DC-to-DC converter is driven first to charge the battery, then the auxiliary load operates. This feedback mechanism ensures reliable auxiliary load operation while keeping the control logic adaptive rather than overly complex.
2Reliability
If the DC-to-DC converter is driven first to charge the auxiliary battery, then the auxiliary load can operate reliably, but the response time for auxiliary load activation is increased
Solution Approach 1:
The control device performs a preliminary determination of the auxiliary battery's state of charge before the auxiliary load activation request is fully processed. This preliminary assessment allows the system to pre-plan the optimal driving sequence, minimizing the actual activation time while ensuring reliability. If the battery has sufficient charge, the auxiliary load starts immediately; if not, the system has already prepared the DC-to-DC converter sequencing.
Solution Approach 2:
The control device dynamically adjusts the driving sequence based on real-time battery state conditions rather than following a fixed sequence. When the auxiliary battery's state of charge is sufficient, the system dynamically switches to a sequence where the auxiliary load is driven first. When the state of charge is insufficient, it dynamically switches to a sequence where the DC-to-DC converter is driven first. This dynamic adaptation optimizes the balance between reliability and activation time.
3Loss of energy
If the auxiliary battery supplies power directly to the auxiliary load without DC-to-DC converter intervention, then the system operates efficiently with minimal energy conversion losses, but the auxiliary load may not operate when battery state of charge is insufficient
Solution Approach 1:
The control device performs a preliminary check of the auxiliary battery's state of charge before allowing direct power supply to the auxiliary load. This preliminary assessment ensures that when direct power supply is permitted, the battery has sufficient charge, thus maintaining energy efficiency while preventing operation failures. The system only intervenes with the DC-to-DC converter when the preliminary check indicates insufficient charge.
Solution Approach 2:
The control device continuously monitors the auxiliary battery's state of charge and uses this feedback to dynamically switch between two operating modes: direct power supply mode (when battery charge is sufficient, minimizing energy conversion losses) and DC-to-DC converter charging mode (when battery charge is insufficient, ensuring reliability). This feedback-based mode switching optimizes the trade-off between energy efficiency and operational 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 vehicle control device ensures reliable operation of the auxiliary load by prioritizing the DC-to-DC converter's operation when the auxiliary battery's state is insufficient, providing electric power from the high-voltage battery via the DC-to-DC converter, thus ensuring the auxiliary load can be driven consistently when the user is on board and the ignition is off.
Implementation Method 1
a DC-to-DC converter configured to supply electric power from the first battery to either or both of the second battery and the auxiliary load
Data Source
AI summary
A vehicle control device for a vehicle includes a processor. The vehicle includes a first battery, a second battery, an auxiliary load powered by the second battery, and a DC-to-DC converter configured to supply electric power from the first battery to either the second battery or the auxiliary load, or to both of the second battery or the auxiliary load. The processor is configured to: determine the state of a start switch and the boarding state of the vehicle; acquire the voltage of the second battery; and when the processor determines that the vehicle is in a non-started on-board state, determine based on the voltage of the second battery an order in which the DC-to-DC converter and the auxiliary load are driven. The non-started on-board state is a state in which the start switch is off and a user is presumed to be in the vehicle.