Rail Vehicle Battery Drive Voltage Regulation
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Solution Overview
Problem
Rail vehicle systems experience poor efficiency and excessive battery usage due to low speed operations, leading to reduced battery lifespan, as existing technologies fail to optimize power conversion and voltage management effectively.
Innovation Solution
A rail vehicle system that includes an intermediate circuit with a rechargeable battery and capacitors, capable of adjusting voltage levels between 750V and 450V to optimize energy usage, using a two-quadrant converter rectifier for dynamic energy management, and switching between line network and battery operation based on speed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the rail vehicle operates in battery mode at low speeds, then the vehicle can run on sections without network, but the system efficiency deteriorates and battery lifespan reduces
Solution Approach 1:
The patent implements dynamic voltage adjustment in the intermediate circuit, switching between a first voltage level (higher) and a second voltage level (lower, matching battery voltage) based on operating conditions. This dynamic adaptation optimizes power conversion efficiency across different speed ranges and operating modes, resolving the contradiction between battery operation capability and system efficiency.
Solution Approach 2:
The patent changes the intermediate circuit voltage parameter according to operating conditions - using a higher first voltage level for improved efficiency during certain operations and a lower second voltage level during battery operation at low speeds. This parameter adjustment optimizes the performance of power converters and reduces energy losses, addressing the efficiency deterioration problem.
2Productivity
If the intermediate circuit voltage is maintained at a high level, then the drive system operates efficiently at higher speeds, but the battery is heavily used and lifespan reduced at low speeds
Solution Approach 1:
The patent dynamically adjusts the intermediate circuit voltage based on the rail vehicle's speed and operating mode. During battery operation at low speeds, the system switches to the second voltage level (matching battery voltage) to reduce battery stress and extend lifespan. During network operation or higher speeds, the system uses the first voltage level to maintain optimal drive system efficiency.
Solution Approach 2:
The patent implements parameter changes in the intermediate circuit voltage between two distinct levels. The second voltage level is specifically selected to match the battery voltage during battery operation, optimizing battery performance and lifespan. The first voltage level is used during network operation to maintain high drive system efficiency, thus resolving the contradiction between productivity and battery duration.
3Adaptability or versatility
If the intermediate circuit voltage is frequently adjusted between voltage levels, then the system adapts to different operating conditions, but the device complexity increases
Solution Approach 1:
The patent implements a dynamic voltage adjustment system that switches between two discrete voltage levels based on operating conditions (battery mode vs. network mode, low speed vs. high speed). This dynamic adaptation enables the system to optimize performance across different scenarios while using a relatively simple switching mechanism rather than continuous complex regulation.
Solution Approach 2:
The patent segments the voltage regulation into two distinct levels - a first voltage level for network operation and high-speed efficiency, and a second voltage level for battery operation and low-speed optimization. This segmentation simplifies the control logic and device complexity compared to continuous voltage adjustment, while still providing effective adaptation to different operating conditions.
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 solution enhances the overall system efficiency and battery lifespan by optimizing voltage levels and energy distribution, reducing battery usage during low-speed operations and maintaining efficiency during higher-speed network operations.
Implementation Method 1
A two-quadrant converter rectifier is used as a means for regulating, in particular for lowering and/or raising the intermediate circuit voltage
Implementation Method 2
The intermediate circuit capacitor is used for energy buffering in the intermediate circuit circuit and for highly dynamic drawing and/or feeding of energy
Implementation Method 3
an energy store, in particular a rechargeable battery and/or one or more capacitors
Data Source
Figure 1
AI summary
The invention relates to a rail vehicle and to a method for operating the rail vehicle which can be battery-operated and which comprises an intermediate circuit voltage and a battery. Said rail vehicle comprises means for providing an intermediate circuit voltage and means for lowering and/or increasing the intermediate circuit voltage between a first and a second voltage level. The second voltage level corresponds to the battery voltage.