Motor Vehicle Charging System Using Segmented Single-Pole Contactors
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Solution Overview
Problem
Existing motor vehicle charging systems require complex and costly multi-pole charging contactors for safe and efficient high-voltage charging, which occupy significant space and complicate cabling.
Innovation Solution
A motor vehicle charging system utilizing a single-phase charging contactor in conjunction with a DC-DC converter that permanently connects the DC voltage charging connection to one input, allowing for potential equalization and electrical isolation of the energy store, reducing installation space and complexity by using a DC-DC converter with switches and storage capacitance to manage pole separation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a multi-pole charging contactor is used to disconnect both poles of the energy storage device, then safety is improved, but device complexity and installation space increase
Solution Approach 1:
The patent divides the electrical connection into three separate circuits: a first circuit for the first pole through the first contactor, a second circuit for the second pole through the second contactor, and a third circuit for the common connection through the third contactor. This segmentation allows each contactor to be simpler (single-pole) while collectively achieving the safety function of isolating both poles, thereby reducing individual contactor complexity while maintaining overall system safety.
Solution Approach 2:
The patent introduces a common connection circuit with a third contactor as an intermediary element that mediates between the two poles and the charging port. This intermediary structure enables independent control of each pole's connection while providing a centralized safety mechanism, reducing the complexity of individual contactors from multi-pole to single-pole designs.
2Reliability
If a multi-pole charging contactor is used, then safety is improved, but installation space and cabling complexity increase
Solution Approach 1:
The patent segments the charging connection into three separate single-pole circuits instead of using a single multi-pole contactor. This segmentation reduces the physical size and installation space required, as three small single-pole contactors occupy less space than one large multi-pole contactor, while also simplifying the cabling structure.
Solution Approach 2:
The patent reorganizes the electrical connection topology by introducing a common connection dimension. Instead of connecting each pole independently to the charging port, the system uses a common connection point that both poles can reference, thereby reducing the complexity of wiring and installation space requirements while maintaining safety through the third contactor's control.
3Reliability
If potential equalization is performed before closing the charging contactor, then safety is improved, but charging time increases
Solution Approach 1:
The patent performs potential equalization between the energy storage device and the charging port before closing the charging contactor to establish safe electrical connection. This preliminary action prevents dangerous potential differences and ensures safety, though it does extend the total charging time by adding this preparatory step.
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 enables compact, cost-effective, and safe high-voltage charging with reduced installation space and simpler cabling, while maintaining high flexibility and safety through bidirectional energy transfer and equipotential bonding.
Implementation Method 1
after connecting the external energy source and before closing the charging contactor, potential equalization between the external energy source and the motor vehicle is carried out by means of the DC-DC converter by operating the DC-DC converter in a pulsed manner
Implementation Method 2
the DC charging connection has a protective conductor connection which is electrically connected via at least one capacitor to the second output connection of the DC-DC converter and via at least one further capacitor to a negative terminal of the energy source
Data Source
AI summary
The invention relates to a motor vehicle (1) comprising an energy store (2) for the intermediate storage of electrical energy, wherein a first electrical pole (9) and a second electrical pole (10) of the energy store (2) are electrically connected to a DC charging connection (5) of the motor vehicle (1) via a DC converter (11), via which DC charging connection the energy store (2) can be electrically connected to an external energy source (3) for charging. In addition, the DC converter (11) is configured in such a way that, in at least one switch position of the DC converter (11), one of the electrical poles (9, 10) is electrically separated from the DC charging connection (5), and the respective other electrical pole (9, 10) can be electrically separated from the DC charging connection (5) by means of a charging contactor (12) that is electrically connected between the DC converter (11) and the DC charging connection (5). The invention also relates to a method for operating a motor vehicle (1).