Controllable Coupling Units for Energy Store Charging
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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 hazards and system breakdowns.
Innovation Solution
The system employs controllable coupling units with full-bridge switching elements to rectify AC voltage from charging transformers, eliminating the need for a separate rectifier unit and allowing for controlled charging current through charging inductances, while also providing isolation and mechanical blocking mechanisms to prevent short circuits and undesired torques.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a separate rectifier unit is used to rectify AC voltage from charging transformers, then reliable voltage conversion is achieved, but device complexity and installation space increase
Solution Approach 1:
The patent combines the rectifier function with the existing full-bridge coupling units that connect battery modules to the inverter. The full-bridge switching elements perform dual functions: enabling battery module disconnection/bypassing and rectifying AC charging voltage. This integration eliminates the need for a separate rectifier unit, reducing device complexity while maintaining reliable voltage conversion.
Solution Approach 2:
The full-bridge coupling units are designed to serve multiple purposes: they provide isolation between battery modules and the inverter, enable bypassing of failed battery cells, and simultaneously function as rectifiers for AC charging voltage. This multi-functionality reduces the overall number of components needed in the charging system.
2Power
If battery cells are connected in series to achieve high voltage, then power requirements are met, but system reliability decreases due to single point of failure
Solution Approach 1:
The battery system is divided into multiple independently controllable battery modules, each with its own full-bridge coupling unit. This segmentation allows individual modules to be isolated or bypassed without affecting the entire battery system, maintaining reliability while achieving high voltage through series connection of modules.
Solution Approach 2:
The system dynamically reconfigures battery module connections through controllable full-bridge switching elements. When a battery cell fails, the system can dynamically bypass that cell or isolate the affected module, adapting the circuit configuration to maintain system operation and reliability while preserving the high-voltage series architecture.
3Power
If additional battery cells are connected in parallel to increase maximum current, then current capacity increases, but device complexity and cost increase
Solution Approach 1:
Instead of using a large number of parallel battery cells to increase current capacity, the system segments the battery into multiple modules with series connection, achieving high voltage. The full-bridge coupling units enable current management and module isolation, allowing the system to meet power requirements through voltage rather than excessive parallel connections, thereby reducing battery 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
This solution enhances system reliability by ensuring constant charging current across phases, reduces costs and installation space, and prevents system failures by isolating the electrical machine during charging, thus ensuring safe and efficient energy storage and transfer.
Implementation Method 1
In a current build-up phase, the voltage in the energy supply branches is lower in terms of amount than on the secondary side of the charging transformer, so that energy is supplied to the charging inductances and stored there
Implementation Method 2
the AC voltage present on the secondary side (secondary winding) of a charging transformer must first be rectified. The invention is based on the basic idea of using the switching elements of the coupling units designed as full bridges to rectify the secondary-side AC voltage of the charging transformers
Data Source
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 each energy supply branch (3-1, 3-2, 3-3) can be connected to and separated from a secondary side (9-1'; 9-1''; 9-2'; 9-2''; 9-3'; 9-3'') of a charging transformer (10'; 10-1''; 10-2''; 10-3'') by a respective controllable switching element (21-1; 21-2; 21-3), an additional charging inductor (20-1; 20-2; 20-3) being arranged in each connecting line between the energy supply branches (3-1, 3-2, 3-3) and the secondary sides (9-1'; 9-1''; 9-2'; 9-2''; 9-3'; 9-3'') of the charging transformer (10'; 10-1''; 10-2''; 10-3'').