Battery Filter Design for Wind Energy Storage Voltage Control
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Solution Overview
Problem
Power generation systems employing battery energy storage face challenges in minimizing common mode and normal mode voltages applied to energy storage batteries, which can be detrimental and require large, costly filters to mitigate these issues.
Innovation Solution
An optimized filter configuration is introduced, where the DC link is directly connected to the common mode filter, and the normal mode inductor is placed only on the IGBT PWM leg output from the converter, minimizing common mode voltage applied to the battery and reducing the size and cost of the common mode inductor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If traditional filter configuration is used with bi-directional DC-DC switching power supply, then common mode and normal mode voltages are filtered, but the filter size and cost increase significantly
Solution Approach 1:
The patent divides the filter into separate common mode and normal mode filter sections with independent inductors and capacitors. The common mode inductor is placed on the DC link, while normal mode inductors are placed on the IGBT PWM legs, allowing each filter to address specific voltage modes without requiring oversized components for both modes simultaneously.
Solution Approach 2:
The patent introduces a common mode inductor as an intermediary component on the DC link between the bi-directional DC-DC switching power supply and the battery. This intermediary component specifically targets common mode voltages before they reach the battery, reducing the burden on other filter components and enabling smaller overall filter size.
2Object-affected harmful factors
If common mode inductor is placed on DC link, then common mode voltage is minimized at battery, but normal mode current interference with common mode filter increases
Solution Approach 1:
The patent segments the filtering function by placing normal mode inductors specifically on the IGBT PWM legs rather than using a single large common mode inductor. This segmentation allows normal mode current to be filtered locally at the source without requiring the common mode inductor on the DC link to handle both common mode and normal mode currents, eliminating the interference problem.
Solution Approach 2:
The patent applies local quality by placing normal mode inductors specifically on the IGBT PWM legs where normal mode currents are generated. This localized filtering approach addresses normal mode interference at its source without affecting the common mode filtering performance on the DC link, allowing each filter to operate optimally for its specific function.
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 effectively isolates normal mode current from the common mode filter, reducing the size and cost of the common mode inductor while minimizing voltage applied to the battery, thus enhancing the protection and efficiency of the battery energy storage system.
Implementation Method 1
An optimized filter configuration is introduced, where the DC link is directly connected to the common mode filter, and the normal mode inductor is placed only on the IGBT PWM leg output from the converter, minimizing common mode voltage applied to the battery
Data Source
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AI summary
A system for operating a power generation system 100 within a battery storage/discharge mode includes a power convertor 162 having a DC link 126, 136, a switching module 142 coupled to the DC link, a storage device 144, and a filter coupled between the storage device 144 and power converter 162. The filter may correspond to a normal mode filter configured to limit normal mode voltage from being applied to the storage device 144. A common mode filter may be associated with the storage device 144. The storage device 144 may correspond to one or more batteries 143 while the power generation system 100 may correspond to a wind-driven generator 120.