Capacitor Stage Voltage Transformation for High Voltage DC
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Solution Overview
Problem
Current technologies for converting high DC voltage to lower DC or AC voltage rely on magnetically-based transformers, which are costly and impractical for small power levels, and lack efficient solutions for high voltage DC transmission due to expensive converter stations and insulation requirements.
Innovation Solution
A method using a series of capacitor stages with switching devices to transfer energy without magnetic transformers, where capacitors are reversely polarized and reconnected to distribute voltage across stages, allowing for efficient DC-to-DC or DC-to-AC conversion by controlling switching frequency based on load demands.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If magnetically-based transformers are used for high voltage DC conversion, then voltage transformation is achieved, but cost and insulation requirements increase significantly
Solution Approach 1:
The patent divides the high voltage DC transformation process into multiple capacitor stages, each operating at a fraction of the total voltage. By segmenting the voltage across series-connected capacitors, the insulation requirements and cost for each individual stage are dramatically reduced compared to a single-stage magnetic transformer approach.
Solution Approach 2:
The patent replaces the magnetic field-based transformation mechanism with an electrostatic capacitor-based system. Instead of using magnetic cores and windings, the invention uses capacitors and switching devices to achieve voltage transformation, eliminating the need for heavy magnetic components and associated insulation.
2Productivity
If converter stations are built for high voltage DC transmission, then efficient long distance power transmission is achieved, but the cost per kilowatt increases for small power levels
Solution Approach 1:
The patent enables segmentation of power transmission needs by allowing intermediate tapping of high voltage DC lines at various power levels. The capacitor-based transformation system can be scaled to match specific load requirements, avoiding the need for full-scale converter stations and reducing cost per kilowatt for smaller power levels.
3Power
If full size bridges are used to convert DC to AC and then to different DC voltage, then voltage conversion is achieved, but device complexity and cost increase
Solution Approach 1:
The patent extracts and eliminates the intermediate AC conversion stage from the traditional DC-AC-DC transformation process. By using capacitors and switches directly to transform high voltage DC to lower voltage DC, the invention removes the complexity of full-size bridges and intermediary transformers, achieving conversion in a single streamlined stage.
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 approach reduces the voltage rating of individual stages, minimizing insulation costs and enabling efficient transformation of high voltage DC to lower voltage DC or AC, making it economically viable for intermediate power levels and reducing the need for expensive converter stations.
Implementation Method 1
a high voltage transformer for transforming electric power from a high voltage direct current source to a lower voltage direct current or to a lower voltage alternating current (ac) without intermediate magnetic transformation comprising a plurality of stages, wherein each stage comprises one or more capacitors
Data Source
AI summary
A high voltage transformer for transforming electric power from a high voltage direct current source to a lower voltage direct current or to a lower voltage alternating current, without intermediate magnetic transformation. The transformer has a number of stages. Each stage includes capacitors and switching devices. There is a controller that controls the switching devices to change the polarity of one or more capacitors.