Pre-chargeable DCDC Circuit Integrating Pre-charging Module
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing DCDC conversion circuits for electric vehicles have defects such as large volume, high cost, and complex control due to a separate pre-charging branch that is not integrated with the DCDC converter, leading to unsafe charging conditions and energy inefficiencies.
Innovation Solution
A pre-chargeable DCDC conversion circuit is designed with a pre-charging module connected in series in the direct-current bus of the low-voltage side conversion module, sharing most power devices and loops with the original DCDC converter, reducing volume and cost, and featuring a controller that manages pre-charging through PWM signals to efficiently charge capacitors during startup.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a separate pre-charging branch is connected in parallel next to the main relay, then pre-charging function is achieved, but device complexity and volume increase
Solution Approach 1:
The pre-charging module is merged with the DCDC converter by connecting the pre-charging inductor in series with the low-voltage side conversion module's direct-current bus. This integration allows the pre-charging function to share power devices and loops with the DCDC converter, eliminating the need for a separate parallel pre-charging branch while maintaining pre-charging safety functionality.
Solution Approach 2:
The DCDC converter is designed to perform multiple functions: during pre-charging, it charges the capacitor through the pre-charging inductor; during normal operation, it performs voltage conversion. The controller switches between pre-charging mode and normal conversion mode, allowing the same circuit to serve dual purposes and reducing overall device complexity.
2Reliability
If a separate pre-charging branch is used, then pre-charging function is achieved, but manufacturing cost increases
Solution Approach 1:
The pre-charging module shares power devices and loops with the DCDC converter, reducing the total component count. The controller manages both pre-charging and normal conversion functions, eliminating the need for separate control circuits and reducing manufacturing costs while maintaining pre-charging safety.
Solution Approach 2:
The DCDC converter performs dual functions as both a pre-charging device and a voltage converter. By reusing existing components for multiple purposes, the manufacturing cost is reduced compared to having separate dedicated pre-charging and conversion circuits.
3Reliability
If a separate pre-charging branch is connected in parallel, then pre-charging function is achieved, but control complexity increases
Solution Approach 1:
The controller manages both pre-charging and normal voltage conversion functions through a unified control mechanism. During pre-charging, the controller activates the pre-charging inductor and monitors capacitor voltage; after pre-charging completes, it switches to normal DCDC conversion mode, simplifying control compared to managing separate pre-charging and conversion 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 solution integrates pre-charging functionality into the DCDC converter, reducing volume and cost, simplifying control, and ensuring safe and efficient charging by reusing existing components, thereby addressing the inefficiencies and safety concerns of prior art.
Implementation Method 1
a primary winding of the secondary transformer is connected in series in the direct-current bus of the low-voltage side conversion module; one end of the secondary winding of the secondary transformer is connected to an anode of a ninth diode D9
Implementation Method 2
one end of the secondary winding of the secondary transformer is connected to an anode of a ninth diode D9, and the other end of the secondary winding of the secondary transformer is connected to a negative bus of the high-voltage side conversion module and one end of a fifth capacitor C5; and a cathode of the ninth diode is connected to the other end of the fifth capacitor and a positive bus of the high-voltage side conversion module
Implementation Method 3
one end of the secondary winding of the secondary transformer is connected to a negative bus of the high-voltage side conversion module and one end of a fifth capacitor C5; and a cathode of the ninth diode is connected to the other end of the fifth capacitor and a positive bus of the high-voltage side conversion module
Data Source
AI summary
A pre-chargeable DCDC conversion circuit includes a high-voltage side conversion module connected to a primary winding of a main transformer T1, a low-voltage side conversion module connected to a secondary winding of the main transformer, and a controller used for controlling the high-voltage side conversion module and the low-voltage side conversion module. A pre-charging module is connected in series in a direct-current bus of the low-voltage side conversion module, and the pre-charging module is used for pre-charging a capacitor of electric equipment connected to a direct-current bus of the high-voltage side conversion module when the complete machine is powered on. The pre-charging module and a forward DCDC share most of power devices and power loops, and only a small number of devices are added, such that the volume and cost are reduced compared with an independent pre-charging branch, and the control mode is simple.