DC Converter Pre-Charge Control with Switched Resistance Branches
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Solution Overview
Problem
The control of direct current (DC) converters in electric vehicles is not flexible enough, affecting the pre-charge efficiency, particularly during the process of inverting low-voltage to high-voltage power supplies.
Innovation Solution
A DC converter system with a pre-charge control unit and controller that adjusts the resistance between a diode and a load resistor to manage current flow, allowing flexible control of the pre-charge process using multiple resistors and switches to optimize current levels based on vehicle states and commands.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the DC converter uses constant current pre-charge control, then the pre-charge process is simple to implement, but the pre-charge efficiency is low and the control is not flexible enough
Solution Approach 1:
The patent implements dynamic pre-charge control by switching between different resistance values (first resistance and second resistance) based on the pre-charge state. The controller dynamically adjusts the pre-charge current by controlling the switching unit to connect different resistance values in the pre-charge control unit, transforming the static constant current control into dynamic adaptive control that improves pre-charge efficiency while maintaining operational simplicity.
2Device complexity
If the DC converter uses a single resistance value for pre-charge, then the circuit structure is simple, but the current control flexibility is insufficient
Solution Approach 1:
The patent segments the pre-charge control by dividing it into multiple branches with different resistance values (first pre-charge branch with first resistance, second pre-charge branch with second resistance). This segmentation allows the system to select appropriate resistance values for different pre-charge stages, providing current control flexibility while keeping each individual branch relatively simple in structure.
Solution Approach 2:
The pre-charge control unit is designed with multi-functionality by incorporating multiple resistance values and switching units that can connect different resistance values to different terminals. This universal design allows the same pre-charge control unit to provide both constant current control and variable current control functions, adapting to different pre-charge requirements without requiring separate control circuits.
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 enhances pre-charge efficiency by dynamically controlling current flow, reducing pre-charge time and improving the overall performance of the DC converter.
Implementation Method 1
a switching unit, wherein a first terminal of the switching unit is connected with a negative electrode of the low-voltage power supply, and a second terminal of the switching unit is connected with a first terminal of the first inductor; and a control terminal of the switching unit is connected with an output terminal of the controller; the controller is configured for controlling the switching unit to be turned on or turned off
Implementation Method 2
a first terminal of the first inductor is connected with a positive electrode of the diode, and a negative electrode of the diode is connected with a first terminal of the pre-charge control unit
Implementation Method 3
a first inductor, wherein a first terminal of the first inductor is connected with a positive electrode of the diode, and a second terminal of the first inductor is connected with a positive electrode of the low-voltage power supply
Implementation Method 4
a first capacitor, wherein the first capacitor is connected in parallel with the load resistor
Implementation Method 5
the controller is configured to control a resistor connected between the negative electrode of the diode and the first terminal of the load resistor in the pre-charge control unit when the switching unit is turned off
Data Source
AI summary
A DC converter, a controlling method, and a vehicle are provided. The DC converter includes: a first inductor, a switching unit, a diode, a first capacitor, a load resistor, a pre-charge control unit and a controller. The output terminal of the controller is connected with the control terminal of the switching unit and the control terminal of the pre-charge control unit. The controller is configured to control the switching unit to be turned on or turned off, and to control the resistor connected between the negative electrode of the diode and the first end of the load resistance in the pre-charge control unit when the switching unit is turned off, such that the direct current converter is pre-charged by the low-voltage power supply.