Low-Voltage DC/DC Converter Control for EV Battery
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Solution Overview
Problem
Existing low-voltage DC/DC converter control systems for electric vehicles inefficiently manage battery charge, leading to reduced mileage and battery durability due to continuous high-voltage output and lack of consideration for battery state, resulting in unnecessary power consumption, dark current discharge, and overcharge/gassing phenomena.
Innovation Solution
Implementing a feedback control system that utilizes information from a low-voltage battery sensor to adjust the charge time and target voltage values of the low-voltage DC/DC converter based on State of Charge (SOC) and liquid temperature, using predefined tables to optimize charging and prevent overcharge and gassing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the low-voltage DC/DC converter operates with fixed high-voltage output (about 14.3V) continuously, then the voltage supply to electric devices is maintained, but unnecessary power is consumed and mileage is reduced
Solution Approach 1:
The patent implements dynamic voltage control where the DC/DC converter adjusts its output voltage based on real-time battery state feedback. Instead of maintaining a fixed 14.3V output, the system dynamically modifies voltage levels according to battery charge state, thereby reducing unnecessary power consumption while ensuring adequate voltage supply when needed.
Solution Approach 2:
The system incorporates a feedback control mechanism that continuously monitors battery state (charge level, temperature) and uses this information to regulate DC/DC converter output. The controller receives battery state information and adjusts the converter's duty cycle accordingly, creating a closed-loop control system that optimizes power delivery and minimizes energy waste.
2Reliability
If the low-voltage DC/DC converter supplies charge power continuously regardless of battery state, then the battery is kept charged, but overcharge and gassing phenomena occur reducing battery life
Solution Approach 1:
The control system uses feedback from battery state sensors to regulate charging. When the battery reaches full charge or optimal voltage levels, the system automatically reduces or stops charging current through duty cycle adjustment, preventing overcharge conditions that cause gassing and extend battery lifespan.
Solution Approach 2:
The system changes operating parameters (voltage, current, duty cycle) based on battery state. By dynamically adjusting these parameters according to charge level and temperature, the system prevents parameter ranges that cause gassing and overcharge, thereby protecting battery life while maintaining charge availability.
3Device complexity
If the low-voltage DC/DC converter operates without utilizing low-voltage battery information, then the control system is simple, but mileage is reduced due to unnecessary power consumption
Solution Approach 1:
The system incorporates feedback control by monitoring battery state through sensors and using this information to regulate DC/DC converter operation. This feedback mechanism enables intelligent power management that reduces unnecessary consumption while maintaining adequate voltage supply, achieving energy efficiency without excessive system complexity.
Solution Approach 2:
The control system performs self-regulation by automatically adjusting converter output based on battery state feedback. The system serves itself by making real-time decisions about power delivery without requiring complex external control, thereby reducing energy waste while maintaining simple architecture.
4Power
If the low-voltage DC/DC converter maintains continuous high-voltage output, then electric devices receive adequate power, but the battery undergoes dark current discharge during idle periods
Solution Approach 1:
The system implements periodic monitoring and control adjustments based on vehicle operation state. During idle periods, the controller reduces or suspends DC/DC converter operation to minimize discharge, while during active operation, it restores full power delivery capability. This periodic action pattern reduces unnecessary energy loss during idle while maintaining power availability when needed.
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 electric vehicle mileage per charge and enhances battery durability by dynamically controlling the low-voltage DC/DC converter based on battery state, reducing unnecessary power consumption and preventing discharge and overcharge-related issues.
Implementation Method 1
a DC/DC converter which generates a direct current by rectifying power of a high-voltage battery
Implementation Method 2
switches a high-voltage DC to generate an AC (alternating current), transforms the AC using a coil, a transformer, or a capacitance, and then rectifies the AC again
Data Source
AI summary
A system and method of controlling a low-voltage DC/DC converter for an electric vehicle that include a battery sensor that senses information regarding a low-voltage battery during a stop of the electric vehicle for each first period when the electric vehicle stops and a controller that operates a low-voltage DC/DC converter to charge the low-voltage battery for a predefined time when an error occurs in the battery sensor. In addition, the controller determines a charge time of the low-voltage battery based on first SOC values of the information regarding the low-voltage battery sensed for each first period when no error in the battery sensor is detected and operates the low-voltage DC/DC converter for the determined charge time to charge the low-voltage battery.