Dual-Battery Power Supply Isolation for Unintended Discharge
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In electric vehicle power supply systems with two electrical storage devices, unintended discharge occurs from a low-voltage second electrical storage device to a high-voltage first electrical storage device during high power requests, leading to voltage differences and potential electrical current imbalances.
Innovation Solution
A power supply system that includes a first and second power circuit connected by a voltage converter, with a power control unit that isolates the second electrical storage device from the power line when a voltage difference threshold is met, and operates the voltage converter to limit the second electrical storage device's output power, ensuring the first storage device covers the requested power and preventing unintended discharge.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the first electrical storage device supplies great power during acceleration, then the drive motor can achieve high performance, but the closed circuit voltage of the first electrical storage device becomes lower than the static voltage of the second electrical storage device, causing unintended discharge from the second electrical storage device
Solution Approach 1:
The voltage converter acts as an intermediary device between the first and second electrical storage devices. It monitors the voltage difference between the two storage devices and controls the passing current to prevent unintended discharge. When the closed circuit voltage of the first storage device drops below the static voltage of the second storage device, the voltage converter blocks reverse current flow, thereby preventing the second storage device from discharging unintentionally while allowing the first storage device to supply great power to the drive motor.
2Productivity
If the second electrical storage device is connected to the power circuit via a voltage converter, then power can be combined from both storage devices, but unintended electrical current may flow through the voltage converter from the second electrical storage device side to the first electrical storage device side when voltage difference occurs
Solution Approach 1:
The control device continuously monitors the voltage levels of both electrical storage devices and adjusts the passing current through the voltage converter accordingly. When the closed circuit voltage of the first storage device becomes lower than the static voltage of the second storage device, the control device detects this voltage difference and modifies the switching control of the voltage converter to prevent reverse current flow. This feedback mechanism allows power combination from both storage devices under normal conditions while preventing harmful unintended current flow when voltage imbalance occurs.
Data Source
AI summary
A power supply system includes: a first power circuit having a first battery and a first power line; a second power circuit having a second battery and a second power line; a voltage converter; a power converter; a first voltage acquisition unit which acquires a first closed circuit voltage lower limit CCVmin1 of the first battery; a second voltage acquisition unit which acquires a second closed circuit voltage lower limit CCVmin2 of the second battery; and a power control unit which operates the second power circuit based on a requested power, in which the power control unit isolates the second battery from the second power lines, in a case of a voltage difference between the first closed circuit voltage lower limit CCVmin1 and the second closed circuit voltage lower limit CCVmin2 becoming less than a first voltage threshold value A while output limitation of the second battery is being requested.