HVDC Converter Damping Unit for EMC Noise Suppression
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Solution Overview
Problem
High-voltage direct current (HVDC) converters based on voltage source converters generate significant high-frequency electromagnetic noise, leading to electromagnetic compatibility (EMC) issues and requiring bulky, expensive filtering components that are challenging to design and maintain, especially for long-term operation in varying environments.
Innovation Solution
A high-voltage converter arrangement incorporating a damping unit configured as an RC-damper with a series connection of capacitors and resistors, strategically placed between switching cells to suppress electromagnetic noise, featuring low inductance and high-frequency effectiveness, and housed in an insulating enclosure for outdoor compatibility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If electromagnetic noise filtering is implemented using traditional filter circuits or damping devices in main current paths, then electromagnetic compatibility requirements are met, but the device becomes bulky, heavy, expensive, and requires additional space
Solution Approach 1:
The patent extracts the damping function from the main current path and places it locally at specific switching cells. By taking out the damping device from the main current path, the solution eliminates the need for bulky magnetic cores while maintaining noise filtering effectiveness. The damping unit is positioned only where needed (at switching cells with high di/dt) rather than throughout the entire current path.
Solution Approach 2:
The patent applies damping devices locally at specific switching cells rather than uniformly across the entire converter. The damping units are strategically placed at switching cells that exhibit high di/dt characteristics, providing targeted noise suppression where it is most needed while avoiding unnecessary weight and cost in other areas of the converter.
2Object-affected harmful factors
If traditional damping devices are placed in main current paths, then high frequency noise is filtered, but the device requires large magnetic cores to avoid saturation under full current load
Solution Approach 1:
The damping function is extracted from the main current path and implemented using non-magnetic components (resistors and capacitors) located at specific switching cells. This extraction eliminates the need for large magnetic cores that would be required if damping devices were placed in the main current path to handle full load currents.
Solution Approach 2:
The patent uses simple resistor-capacitor networks instead of expensive, large magnetic core devices. The RC-based damping units are compact, inexpensive components that provide effective high-frequency noise filtering without the saturation issues and large volumes associated with magnetic cores.
3Object-affected harmful factors
If filtering components are specially designed to comply with EMC requirements, then electromagnetic compatibility is achieved, but material and engineering costs become significant
Solution Approach 1:
The patent segments the damping function into individual, standardized RC units that can be independently implemented at specific switching cells. This segmentation allows for modular design and assembly, reducing engineering complexity and manufacturing costs compared to custom-designed full-system filters.
Solution Approach 2:
The damping units use standard, off-the-shelf resistor and capacitor components that can be purchased from regular suppliers rather than requiring specially designed EMC components. These universal components perform multiple functions (noise filtering, voltage division, protection) and can be used across different switching cells and converter designs.
4Object-affected harmful factors
If damping devices are designed to carry full low frequency current, then high frequency filtering is provided, but the device requires careful design and large magnetic cores to avoid saturation
Solution Approach 1:
The damping function is extracted from the main current path where it would need to handle full low-frequency current. By placing RC-based damping units locally at switching cells, the solution provides high-frequency filtering without requiring the damping device to carry full load current, thereby eliminating saturation concerns and complex magnetic core design.
Solution Approach 2:
The patent replaces magnetic core-based damping devices with electronic RC circuits. This substitution eliminates the mechanical/magnetic saturation issues and complex core design requirements, using simple resistor-capacitor networks that are easier to design, manufacture, and maintain.
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 efficiently reduces high-frequency noise, minimizes space and cost requirements, and ensures reliable operation for over 30 years in both indoor and outdoor environments, addressing EMC challenges while preventing costly design adaptations.
Implementation Method 1
A high-voltage converter arrangement incorporating a damping unit configured as an RC-damper with a series connection of capacitors and resistors, strategically placed between switching cells to suppress electromagnetic noise
Data Source
Figure 1
Figure 2A
Figure 2B
AI summary
A High-Voltage converter arrangement (1) comprises a plurality of switching cells (10a, ..., 10x), and at least one damping unit (50) being configured to dampen electromagnetic noise caused by a switching operation within the switching cells (10a, ..., 10x). The switching cells (10a, ..., 10x) are interconnected in series by a galvanic connection (20). The at least one damping unit (50) is arranged between a cell potential of a first of the switching cells (10a, 10j) and a cell potential of a second of the switching cells (101, 10v), and at least another one of the switching cells (10a, ..., 10x) is arranged between the first switching cell (10a, 10j) and second switching cell (101, 10v).