Vehicle DC-DC Converter Burst Mode Current Limiting
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Solution Overview
Problem
Conventional low-voltage DC-to-DC converters for vehicles do not effectively limit discharge current during burst mode operations, leading to excessive discharge current and potential battery deterioration, which shortens the lifespan of auxiliary batteries.
Innovation Solution
An apparatus and method that include a signal selector for choosing between charging and burst mode voltage commands, a battery charge/discharge current limiter to generate compensation values for limiting currents, and a controller to adjust output voltage, ensuring appropriate current limiting in both charge and discharge states.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the LDC operates in burst mode to provide power to electric loads, then the power supply capability is improved, but excessive discharge current flows causing battery deterioration
Solution Approach 1:
The control apparatus monitors the discharge current in real-time and compares it with a predetermined threshold value. When the discharge current exceeds the threshold, the control apparatus adjusts the LDC operation to limit the current, creating a closed-loop feedback system that prevents battery deterioration while maintaining power supply capability.
Solution Approach 2:
The system dynamically changes the voltage command parameter based on the discharge current level. When excessive discharge current is detected, the control apparatus modifies the voltage command to reduce the discharge current to within acceptable limits, thereby protecting the battery while allowing burst mode operation to continue.
2Loss of energy
If the LDC outputs minimum voltage in burst mode, then the power conversion efficiency is improved, but uncontrolled discharge current damages the auxiliary battery
Solution Approach 1:
The control apparatus dynamically adjusts the voltage command based on real-time discharge current conditions. Instead of maintaining a fixed minimum voltage, the system adaptively modifies the voltage output to balance conversion efficiency with battery protection, allowing the voltage to vary within a controlled range during burst mode operation.
Solution Approach 2:
The control apparatus acts as an intermediary between the LDC and the auxiliary battery, inserting a control layer that regulates the discharge current. This intermediary function allows the system to maintain efficient power conversion while preventing harmful discharge currents from reaching the battery through active current monitoring and voltage adjustment.
Data Source
AI summary
An apparatus for controlling a low-voltage DC-to-DC converter of a vehicle for converting high-voltage power into low-voltage power may include a signal selector for selecting and outputting one of a charging-oriented voltage command for charging the battery or a preset burst mode voltage command for operation of the low-voltage DC-to-DC converter in a burst mode in which the battery cannot be charged, a battery charge/discharge current limiter for generating a voltage command compensation value for limiting charge current of the battery when the signal selector outputs the charging-oriented voltage command and limiting discharge current of the battery when the signal selector outputs the burst mode voltage command, and a controller for controlling an output voltage of the low-voltage DC-to-DC converter to follow a compensated voltage command generated by applying the voltage command compensation value to the voltage command output by the signal selector.