Energy Store Charging via Machine Star Point
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Solution Overview
Problem
Conventional energy storage systems in electric vehicles and wind turbines face reliability issues due to the series connection of battery cells, where a single cell failure can cause the entire system to fail, leading to potential safety threats and system downtime.
Innovation Solution
A charging system that electrically connects energy storage cells to an external energy source without additional charge components, allowing simultaneous charging across all energy supply branches with individually set charging currents, using a current source or a voltage source with step-up converters and motor inductances to ensure reliable charging.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stress or pressure
If battery cells are connected in series to achieve high overall voltage, then the voltage requirement is met, but the system reliability deteriorates because a single cell failure causes the entire energy store to fail
Solution Approach 1:
The energy store is segmented into multiple independent energy supply branches, each capable of operating autonomously. This segmentation allows the system to maintain functionality even when individual branches fail, thus improving reliability while maintaining the required voltage levels through series connection within each branch.
Solution Approach 2:
Each energy supply branch is equipped with individual coupling units that can independently control and bypass specific battery cells. This local control capability ensures that failures in one branch do not propagate to other branches, maintaining system reliability while achieving high voltage through series connection of cells within each branch.
2Power
If additional battery cells are connected in parallel to increase maximum current, then the current capacity is improved, but the device complexity increases
Solution Approach 1:
The system segments the energy store into multiple energy supply branches with series-connected cells, eliminating the need for parallel connections to achieve high current. Each branch can be independently controlled to provide the required current capacity, reducing overall system complexity while maintaining power output.
Solution Approach 2:
The coupling units dynamically control the connection and disconnection of battery cells in each energy supply branch, enabling flexible current distribution without requiring permanent parallel connections. This dynamic control achieves the required maximum current while simplifying the overall device structure.
3Ease of operation
If conventional charging systems are used with additional charge components, then the charging function is provided, but the device complexity and cost increase
Solution Approach 1:
The coupling units perform multiple functions: they control individual battery cells, enable bypassing of failed cells, and facilitate charging operations. This multi-functionality eliminates the need for separate charge components, reducing device complexity while maintaining ease of operation for charging.
Solution Approach 2:
The charging function is merged with the existing coupling units and energy supply branches. The coupling units that already control battery cell connections are also used to manage charging current distribution, eliminating the need for additional dedicated charging components and reducing overall system complexity.
4Object-affected harmful factors
If the entire energy store is interrupted due to a single cell failure, then the system safety is maintained, but the productivity and availability deteriorate
Solution Approach 1:
The energy store is divided into independent energy supply branches, each with its own coupling units. When a cell failure occurs in one branch, only that branch is interrupted while other branches continue to operate, maintaining system availability and productivity while ensuring safety through isolated failure containment.
Solution Approach 2:
Instead of interrupting the entire energy store when a cell fails, the system inverts the approach by maintaining operation of healthy branches and isolating only the failed branch. This inversion of the conventional approach preserves productivity and availability while maintaining safety through selective interruption.
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 reliability of energy storage systems by enabling simultaneous charging of all energy storage cells, reducing the risk of system failure and ensuring continuous operation, even in critical applications like wind turbines and electric vehicles.
Implementation Method 1
an external energy source (10, 10') which can be connected to the star point of the electrical machine (1)
Implementation Method 2
a voltage source (10'') whose voltage value is below the voltages of the energy supply branches (3-1 to 3-3). However, since the charging current is not automatically limited by the voltage source, this cannot easily be connected in parallel with the controllable energy store acting as a voltage source. However, this problem is solved in that the coupling units can be operated as step-up converters in conjunction with motor inductances of the electrical machine (1).
Data Source
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AI summary
The invention relates to a system for charging at least one energy storing cell (5) in a controllable energy store (2) that is used to control and supply electric energy to an n-phase electric machine (1), wherein n > 1. The controllable energy store (2) has n parallel energy supply branches (3-1, 3-2, 3-3), each of which has at least two serially connected energy storing modules (4), each said energy storing module comprising at least one electric energy storing cell (5) with a corresponding controllable coupling unit (6). The energy supply branches (3-1, 3-2, 3-3) can be connected to a reference bus (T-), and each energy supply branch can be connected to a phase (U, V, W) of the electric machine (1). The coupling units (6) bridge the respective corresponding energy storing cells (5) or connect same into the respective energy supply branch (3-1, 3-2; 3-3) dependent on control signals. The aim of the invention is to allow at least one energy storing cell (5) to be charged. This is achieved in that an external energy source (10) can be connected to a neutral point (S) of the electric machine (1) and to the reference bus (T-).