Variable Step-Down Converter for EV Charging Stations
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Solution Overview
Problem
High-power variable step-down converters for electric vehicle charging stations experience significant energy losses, leading to increased costs due to high power loss dissipation, especially as input voltage increases.
Innovation Solution
A variable step-down converter design that cascades non-controllable and controllable voltage converters, utilizing a transformer to divide the input voltage into partial voltages and employing pulse width modulation to minimize losses, with the option to combine controllers into a single unit for efficient operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If high voltage mains power is converted to lower voltage charging current using conventional step-down converters, then voltage conversion is achieved, but energy losses increase in proportion to the input voltage
Solution Approach 1:
The patent divides the voltage conversion process into multiple stages by cascading several step-down converters. Each converter handles a portion of the total voltage reduction, so that no single converter experiences the full input voltage stress. This segmentation reduces the energy losses in each individual converter and overall system efficiency is improved.
Solution Approach 2:
The patent introduces intermediate voltage levels between the high voltage mains power and the final charging voltage. Multiple step-down converters are connected in cascade, with each converter producing an intermediate voltage that serves as input to the next converter. This intermediary approach allows progressive voltage reduction with minimized energy losses at each stage.
2Productivity
If high-power variable step-down converters are used for electric vehicle charging, then charging capability is achieved, but power loss dissipation costs increase
Solution Approach 1:
The high-power charging capability is achieved by cascading multiple step-down converters, where each converter operates at a manageable voltage level. This segmentation allows the system to deliver high charging capacity while avoiding the excessive power losses that would occur in a single high-voltage converter, thereby reducing operational costs.
Solution Approach 2:
The patent changes the operating parameters of the converters by operating them at different voltage levels in cascade. Each converter is optimized for its specific voltage range, allowing the system to achieve high charging capacity while maintaining efficient operation and minimizing power loss dissipation costs.
3Adaptability or versatility
If standardized voltage converters are cascaded to achieve high voltage conversion, then voltage regulation is achieved, but device complexity increases
Solution Approach 1:
The voltage regulation capability is achieved by cascading standardized step-down converters, with each converter providing a portion of the total voltage reduction. While this segmentation does increase the number of components, it allows the use of standardized, off-the-shelf modules rather than requiring a single complex custom-designed converter.
Solution Approach 2:
The patent uses identical or standardized step-down converter modules in cascade, where each module is multi-functional and can operate independently. This universality allows for easier maintenance, replacement, and scaling, offsetting the increased device complexity through modular standardization.
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 design reduces power losses and costs by utilizing lower dielectric strength switches and non-controllable converters, achieving efficient voltage regulation with minimal feedback and reduced manufacturing and operational expenses.
Implementation Method 1
a transformer (11) dividing an input voltage into a plurality of partial voltages
Implementation Method 2
a controller (6) with a pulse width modulator regulating the output voltage to different values
Data Source
Figure 1~2
Figure 3
Figure 4
AI summary
Variable step-down converter comprising a voltage output (4), at least one first adjustable voltage converter (1) with a first voltage input (21) and a first switch (31), at least one first secondary winding connected to the first voltage input (21), a first control (6) of the adjustable voltage converter (1) for detecting an actual voltage and current at the voltage output (4) of the variable step-down converter, querying a target voltage and outputting a first control signal (61) to the switch (31) of the adjustable voltage converter (1) to adjust the actual voltage to the target voltage, n second voltage converters in the form of non-adjustable voltage converters (5, 5') each with a second voltage input (22, 22') and each with a second switch (32, 32'), where n is an integer greater than or equal to 1, at least one second secondary winding (10),wherein each second secondary winding (10) is connected to one of the second voltage inputs (22), a cascade of the first and second voltage transformers (1, 5, 5') and a second controller (7) for outputting the set voltage to the first controller (6) and for outputting a set of n second control signals with one control signal for each of the second switches (32, 32'), wherein the set of n second control signals defines how many of the n second voltage transformers (5, 5') are connected in series with the at least one adjustable voltage transformer (1) when cascaded in series with the voltage output (4) of the variable buck converter.