Modular Power Converter Circuit for Electric Vehicle Traction Drives
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Solution Overview
Problem
The existing modular high-frequency converter circuits for vehicle drives are limited in their ability to store electrical energy, particularly during regenerative braking, due to small capacity intermediate circuit capacitors and lack the capability to connect external power sources.
Innovation Solution
The power converter circuit includes additional supply modules with energy storage devices like supercapacitors or batteries, and the option to connect external power sources, such as photovoltaic units or fuel cells, to enhance energy storage and provide peak power requirements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of moving object
If intermediate circuit capacitors with small capacity are used in submodules, then the converter circuit remains compact and lightweight, but the ability to store electrical energy temporarily is severely limited
Solution Approach 1:
The converter circuit is divided into multiple independent submodules, each with its own intermediate circuit capacitor. This segmentation allows the system to maintain compactness at the submodule level while the aggregate energy storage capacity across all submodules provides sufficient temporary energy storage for regenerative braking and peak power requirements.
2Quantity of substance
If conventional intermediate circuit converters are used, then energy storage capacity is sufficient, but the converter circuit becomes larger and more complex
Solution Approach 1:
The submodules are designed with multi-functionality, serving both as voltage conversion units and as energy storage elements. Each submodule's intermediate circuit capacitor contributes to both the operational voltage regulation and the aggregate energy storage capacity, eliminating the need for separate dedicated energy storage components and reducing overall system complexity.
3Weight of stationary object
If the converter circuit is designed for compactness with small components, then weight and size are reduced, but the capability to handle peak power demands is compromised
Solution Approach 1:
The intermediate circuit capacitors in the submodules continuously maintain charged state during normal operation, storing energy in advance. During peak power demands or regenerative braking events, this pre-stored energy is immediately available, allowing the compact converter circuit to rapidly respond to power fluctuations without requiring larger heavy-duty components.
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 configuration allows for effective temporary storage of recuperated energy and quick supply of power during peak loads, improving the efficiency and compactness of the converter circuit.
Implementation Method 1
The submodules (11), and thus the converter circuit (4) itself, draw electrical power via an inductance (10) from a power source (5) which emits a DC voltage
Implementation Method 2
an intermediate circuit capacitor (22) connected in parallel with the half bridge (20) and the full bridge (21) in the intermediate circuit (25)
Implementation Method 3
additional supply modules (50a, 50b), which serve to store or supply electrical energy
Data Source
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AI summary
The invention relates to an improved power converter circuit (4) for the traction drive of an electric vehicle, comprising at least two submodules (11) connected in series, wherein the power converter circuit (4) extracts electrical power from a DC voltage (Ub)-emitting power source (5) via an inductance (10). Each submodule (11) has at its input side a single-phase half bridge (20) and at its load side a single-phase full bridge (21), wherein the half bridge (20) and the full bridge (21) are on the DC voltage side connected in parallel in conjunction with an intermediate circuit capacitor (22) in an intermediate circuit (25). In order to store or supply electrical energy, the power converter circuit (4) comprises in a first variant, in addition to the submodules (11), at least one supply module (50a, 50b), which has on the input side a single-phase half bridge (20), to which an intermediate circuit capacitor (11) and a further power converter (40, 51) are connected in parallel on the DC voltage side via an intermediate circuit (25), wherein an additional electric power source (46, 52) is or can be connected to the further power converter (40, 51). In a second variant of the power converter circuit (4), at least one of the submodules (11) comprises an additional power converter (40) which is connected in parallel to the full bridge (21) in the intermediate circuit (25) and to which an additional electrical power source (46) is or can be connected.