Rail Vehicle Power Supply Assembly Active Filtering
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Solution Overview
Problem
Existing electrical energy supply arrangements for rail vehicles are heavy and cumbersome due to the need for large input transformers and inductances, especially when operating on AC voltage networks at 16.7 Hz or 50 Hz, and require additional components for DC voltage networks to manage interference and voltage fluctuations.
Innovation Solution
An electrical energy supply arrangement that operates a rectifier arrangement as an active filter, converting DC voltage to AC voltage at a higher frequency (8-20 kHz) for transformer operation, allowing for smaller, lighter transformers and reduced weight by using the rectifier arrangement to compensate for interference currents on both AC and DC voltage networks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If a large input transformer is used for AC voltage networks at low frequencies (16.7 Hz or 50 Hz), then the transformation of high voltage to lower voltage is achieved, but the weight and size of the system increase significantly
Solution Approach 1:
The patent changes the operating frequency parameter from low frequency (16.7 Hz or 50 Hz) to high frequency (8-20 kHz). This parameter change allows the use of a much smaller transformer while achieving the same power transformation capability, directly resolving the contradiction between power transformation and transformer weight
Solution Approach 2:
The patent replaces the traditional low-frequency mechanical/electromagnetic transformation system with a high-frequency switching system. By using pulse-width modulation (PWM) and high-frequency switching, the system achieves voltage transformation without requiring a large low-frequency transformer
2Reliability
If a large input inductance is used for DC voltage networks to filter interference and manage voltage fluctuations, then interference compensation is achieved, but the weight and size of the system increase significantly
Solution Approach 1:
The patent replaces the passive inductance-based filtering system with an active filtering system using power electronic switches. The active filter dynamically compensates for interference currents and voltage fluctuations without requiring large passive inductors, thus reducing weight while maintaining reliability
Solution Approach 2:
The patent introduces dynamic control through switching elements that actively adjust to compensate for interference. Instead of relying on fixed passive components, the system uses dynamic switching to achieve interference filtering, allowing for much smaller component sizes
3Reliability
If additional active filter components are added to DC voltage networks to compensate for interference currents, then interference compensation is improved, but the device complexity and weight increase
Solution Approach 1:
The patent designs a universal power electronic system that performs multiple functions: voltage transformation, interference filtering, and voltage fluctuation management. By making the system multi-functional, additional dedicated filter components are eliminated, reducing overall device complexity while maintaining interference compensation capability
Solution Approach 2:
The patent merges the functions of voltage transformation and interference filtering into a single integrated power electronic system. Instead of having separate transformers and filters, the high-frequency switching system performs both functions simultaneously, reducing component count and system complexity
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 significantly reduces the weight and size of the energy supply system by eliminating the need for large transformers at low frequencies and minimizing the weight of input inductances, while effectively compensating for interference currents, leading to improved efficiency and reduced losses.
Implementation Method 1
the secondary AC voltage present on the secondary side of the transformer is rectified by a second rectifier
Implementation Method 2
Active filters have already been proposed for operation on DC voltage supply networks, which generate AC voltages and thus AC currents, which compensate for the interference currents generated during operation of the traction inverter
Data Source
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AI summary
The invention relates to an electrical power supply assembly for drive units of rail vehicles, wherein the power supply assembly has a first electrical terminal (10) for making contact between the assembly and an electrical power supply network and a second electrical terminal (21, 22) for making contact between the assembly and an intermediate direct current voltage circuit (ZK). A rectifier assembly (M1, M2, M3, M4) for operating the rail vehicle on an alternating current voltage network is connected via a first filter (2) to the first electrical terminal (1) and has at least one module (M), in which a first rectifier (15) is connected via an inverter (16) and a transformer (17) to a second rectifier (18), wherein the first rectifier (15) is connected on the alternating current voltage side via the first filter (2) to the first electrical terminal (1), wherein the second rectifier (18) is connected on the direct current voltage side to the second electric terminal (21, 22), and wherein in the event of a plurality of the modules (M) the alternating current voltage terminals (19, 20) of the first rectifiers (15) are connected in series, but the direct current voltage terminals (21, 22) of the second rectifiers are connected in parallel. An electrical connection (5) for operating the rail vehicle on a direct current voltage network has a second filter (3) and the electrical connection (5) connects the first electrical terminal (1) to the second electrical terminal (21). A control device (37) for controlling the operation of the first rectifier (15) or the first rectifiers (15) while the rail vehicle is operated on a direct current voltage network is equipped such that an alternating current voltage is generated at the first electrical terminal (1) by controlling switching times of semiconductor switches (G) of the first rectifier (15) or first rectifiers (15), wherein said alternating current voltage compensates for or reduces to an acceptable level an electrical alternating current which is a parasitic current flowing through the electrical connection (5) because of the operation of the drive unit of the rail vehicle by the intermediate direct current voltage circuit (ZK).