Vehicle DC/DC Converter Control for Auxiliary Voltage Stability
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In vehicles with high-power driving motors, the auxiliary machine battery's output current changes significantly during startup of high-current consuming devices like electrically controlled brake systems and electrical power steering, leading to unstable voltage supply when multiple devices are used simultaneously, which can decrease the output voltage and affect the operation of auxiliary machines.
Innovation Solution
A power supply system that includes a DC/DC converter with a controller that detects the working state of auxiliary machines like electric power steering and electrically controlled brake systems, adjusts the control gain, and performs voltage or current feedback control to maintain stable output voltage by raising the control gain and switching between voltage and current feedback modes based on the operating state of these machines.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the auxiliary machine battery provides high current to multiple auxiliary machines simultaneously, then the power supply capacity is sufficient, but the output voltage becomes unstable and decreases
Solution Approach 1:
The DC/DC converter acts as an intermediary between the high-voltage battery and the auxiliary machines. It converts high-voltage/low-current output from the high-voltage battery into low-voltage/high-current output required by auxiliary machines, enabling stable power supply during high-current operations without directly drawing large current from the auxiliary machine battery
Solution Approach 2:
The system dynamically adjusts the control gain of the DC/DC converter based on the operating state of auxiliary machines. When auxiliary machines requiring large current are detected to be operating, the control gain is increased to enhance the converter's responsiveness and current supply capability, thereby maintaining voltage stability
2Reliability
If the control gain of the DC/DC converter is increased to improve responsiveness, then the voltage stability improves, but the device complexity increases
Solution Approach 1:
The control gain is made dynamic rather than fixed. The controller adjusts the control gain based on the operating state of auxiliary machines - using higher gain when auxiliary machines requiring large current are operating, and lower gain during normal operations. This dynamic adjustment maintains voltage stability while avoiding unnecessary complexity during normal conditions
Solution Approach 2:
The system implements feedback control by monitoring the operating state of auxiliary machines and adjusting the DC/DC converter's control gain accordingly. The controller receives feedback signals from auxiliary machines and modifies the converter's control parameters to maintain optimal performance without excessive complexity
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 system effectively prevents voltage drops during high-current operations by improving responsiveness and output of the DC/DC converter, ensuring stable power supply to auxiliary machines by dynamically adjusting control strategies based on the working state of the machines.
Implementation Method 1
a DC/DC converter (12) having an input terminal connected with the high-voltage battery (10) and having an output terminal connected with the auxiliary machine battery (20)
Data Source
Figure 1
Figure 2
Figure 3
AI summary
A power supply system for a vehicle includes a high-voltage battery (10) that supplies electric power to an on-vehicle motor, a low-voltage battery (20) that supplies electric power to a plurality of on-vehicle auxiliary machines (22, 24), a DC/DC converter (12) that changes voltage of an output from the high-voltage battery (10) and supplies the resulting output to the low-voltage battery (20), and a controller (14) that detects a working state of at least one of the plurality of on-vehicle auxiliary machines (22, 24), and controls operation of the DC/DC converter in accordance with the detected working state.