Power Phase Module for Rail Converters with Low Inductance Design
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Solution Overview
Problem
Power converters in rail vehicles face inefficiencies due to high inductance in connections, leading to power losses, especially in modular converters used in electric motors, where long connections result in significant inductance and associated losses.
Innovation Solution
A power phase module for modular converters is designed with a compact structure, featuring a DC terminal pair, a DC capacitor terminal pair connected in parallel, a switching device for voltage conversion, and a cooling device, with the intermediate circuit capacitor module placed close to the switching device to minimize inductance and optimize efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If power converters use long connections to the intermediate circuit, then the converter can be modular and easier to assemble, but the inductance increases and power losses increase
Solution Approach 1:
The converter is divided into modular power phase modules that can be independently assembled and connected to the intermediate circuit. Each module contains its own switching devices and associated components, allowing flexible assembly while maintaining compact connection lengths through proper modular design.
Solution Approach 2:
The intermediate circuit capacitor modules are positioned in the spatial dimension directly adjacent to the switching devices rather than being connected through long conductor paths. This dimensional repositioning reduces the effective length of current loops and minimizes inductance while preserving modular assembly capabilities.
2Loss of energy
If the intermediate circuit capacitor module is placed close to the switching device, then inductance is reduced and efficiency improves, but the device complexity increases
Solution Approach 1:
The intermediate circuit capacitor module is merged with the power phase module as an integrated unit. The capacitor module includes connection elements that directly connect to the switching device terminals, combining multiple functions (intermediate circuit capacitance, voltage filtering, and low-inductance connection) into a single modular component that reduces overall system complexity despite the close placement.
Solution Approach 2:
The intermediate circuit capacitor module serves multiple functions simultaneously: it provides the intermediate circuit capacitance, acts as a voltage buffer, and serves as a low-inductance connection point for the switching device. This multi-functionality justifies the integrated design and reduces the need for separate components, thereby managing device complexity.
3Loss of energy
If conductor loop sizes are minimized, then inductance and power losses are reduced, but the manufacturing precision requirements increase
Solution Approach 1:
The intermediate circuit capacitor module is pre-assembled with the switching device in a predetermined configuration that guarantees minimal conductor loop dimensions. The connection elements are pre-positioned and pre-connected during module assembly, eliminating the need for precise field adjustments and reducing manufacturing precision requirements while maintaining small loop sizes.
Solution Approach 2:
The connection elements of the intermediate circuit capacitor module are designed to create equipotential connections with the switching device terminals. By ensuring that connected points are at the same potential, the design minimizes voltage differences across conductor loops, thereby reducing the impact of minor dimensional variations and lowering manufacturing precision requirements.
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 reduces inductance and power losses by minimizing conductor loop sizes, enhancing the efficiency of power conversion and extending the life of intermediate circuit capacitors, while allowing for modular and space-saving arrangements in converters.
Implementation Method 1
a cooling device to carry heat from the power phase module away, in particular out of the switching device
Implementation Method 2
a cooling device to carry heat from the power phase module away
Data Source
AI summary
A power phase module has at least one first DC terminal pair on a face of the power phase module with respective connection elements for connection to a current bar pair. The power phase module further has a first DC capacitor terminal pair on the face being spaced apart from the first DC terminal pair and connected in parallel with it and having respective connection elements for connection to an intermediate circuit capacitor module associated with the power phase module. The power phase module further has a first AC terminal on another side of the power phase module and a switching device connected with the first AC terminal and the first DC terminal pair for converting a direct voltage. The power phase module further has a cooling device to carry heat out of the power phase module. Further proposed are a converter and a rail vehicle with a converter.