Vehicle Battery Charging Control System LDC Bypass
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Solution Overview
Problem
The existing vehicle battery charging systems have low efficiency in delivering power to electric devices and low-voltage batteries, which reduces fuel efficiency, as the low-voltage DC-DC converter (LDC) operates continuously and reduces the power delivery efficiency of the on-board battery charger (OBC).
Innovation Solution
A vehicle battery charging control system that connects the low-voltage DC-DC converter (LDC) to an AC power source instead of the high-voltage battery during charging, using a controller to manage switching units and include a power factor corrector (PFC) and DC-DC conversion circuit to optimize power delivery, thereby preventing reduction in OBC efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the LDC continuously operates to supply power to electric devices and low-voltage battery, then the power delivery to electric devices is ensured, but the power delivery efficiency of the OBC is reduced
Solution Approach 1:
The patent segments the power delivery path into two independent channels: (1) OBC → high-voltage battery → LDC → low-voltage battery/electric devices, and (2) OBC → low-voltage battery/electric devices. The controller selectively activates the second channel during charging to bypass the LDC, thereby segmenting the harmful effect of continuous LDC operation from the necessary power delivery function.
Solution Approach 2:
The system dynamically switches between different power delivery configurations based on operating conditions. During charging, the controller opens the switching unit to disconnect the LDC from the high-voltage battery, creating a dynamic reconfiguration that adapts the power path to current needs and maintains high efficiency.
2Power
If the LDC is connected to the high-voltage battery during charging, then the power delivery to electric devices is maintained, but the OBC power delivery efficiency is reduced
Solution Approach 1:
The controller acts as an intermediary that manages the switching unit to control the connection between the LDC and the high-voltage battery. By mediating this connection, the controller enables the system to selectively bypass the LDC during charging operations, thereby protecting the OBC efficiency while still allowing the LDC to function when needed.
3Reliability
If the LDC operates continuously, then the electric devices receive continuous power, but the fuel efficiency is reduced
Solution Approach 1:
The system employs periodic action by alternately using two power delivery modes: (1) continuous LDC operation for power supply reliability, and (2) OBC direct output mode for high efficiency during charging. The controller periodically switches between these modes based on whether the vehicle is charging or operating, thereby achieving both reliability and fuel efficiency through time-based segmentation of operations.
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 increases the efficiency of power delivery to electric devices and low-voltage batteries, improving fuel efficiency and reducing charging time and electricity costs, while also simplifying the system structure by sharing components like EMI filters and relays.
Implementation Method 1
a first charging circuit configured to convert an alternating current (AC) voltage received from an external AC power source into a direct current (DC) voltage
Implementation Method 2
a second charging circuit configured to convert the AC voltage received from the external AC power source into a DC voltage
Implementation Method 3
including a DC-DC conversion circuit configured to output the DC voltage
Data Source
AI summary
Disclosed herein is a vehicle battery charging control system, which is capable of increasing efficiency of power delivered to an electric device and a low-voltage battery to improve fuel efficiency, by connecting a low-voltage DC-DC converter (LDC) to an AC power source instead of a high-voltage battery upon charging a low-voltage battery of a vehicle to prevent power delivery efficiency of an on-board battery charger (OBC) from being reduced.