Lossless DC Power Conversion via Capacitive Energy Transfer
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Solution Overview
Problem
Existing DC power supplies and converters face issues such as power losses, electromagnetic interference (EMI), larger size, higher mass, and higher cost due to the use of transformers and rectifiers, as well as limitations in input and output voltage ranges and polarities.
Innovation Solution
A method and device for energy transfer between a storage capacitor and an input voltage source using successive energy transfer via coils and capacitors, with zero-current and zero-voltage switching to achieve lossless energy transfer, enabling operation with any polarity input voltage, including AC, and isolating the input voltage source from the storage capacitor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If transformers and rectifiers are used in DC power supplies and converters, then isolation and AC input voltage transformation are achieved, but power losses, electromagnetic interference (EMI), larger size, higher mass, and higher cost occur
Solution Approach 1:
The patent extracts and eliminates the transformer component from the power conversion system. By using direct capacitive energy transfer between input and output capacitors through controlled switching, the invention removes the source of power losses and EMI associated with transformers while maintaining the essential isolation and voltage transformation functions through alternative means.
Solution Approach 2:
The patent introduces controlled switching elements (transistors, diodes, capacitors) as intermediaries to transfer energy directly between input and output without requiring a transformer. The switching network acts as a mediator that enables isolated DC-DC conversion through capacitive coupling and resonant energy transfer, eliminating the need for traditional magnetic isolation components.
2Reliability
If transformers are used in power converters, then voltage transformation and isolation are achieved, but device size and mass increase
Solution Approach 1:
The patent removes the heavy transformer component from the power converter architecture. By implementing isolated DC-DC conversion through capacitive energy transfer and controlled switching, the invention achieves the required isolation capability without the mass penalty of magnetic components, resulting in a significantly lighter device.
3Adaptability or versatility
If rectifiers are used for AC input conversion, then AC to DC conversion is achieved, but systematic power losses occur
Solution Approach 1:
The patent implements continuous energy transfer through resonant oscillating circuits that maintain continuous current flow between input and output capacitors. This eliminates the discontinuous conduction mode and associated losses in traditional rectifier-based converters, achieving efficient AC-to-DC conversion with minimal power loss throughout the conversion process.
4Power
If traditional power conversion methods are used, then voltage conversion is achieved, but electromagnetic interference (EMI) particularly during switching occurs
Solution Approach 1:
The patent utilizes resonant oscillating circuits that operate at predetermined frequencies to transfer energy between capacitors. By designing the switching network to operate at resonant frequencies, the invention minimizes electromagnetic interference during switching transitions while maintaining efficient voltage conversion capability.
5Power
If conventional DC-DC converters are used, then power conversion is achieved, but operational limitations on input source voltage range and type occur
Solution Approach 1:
The patent creates a universal power conversion architecture that can handle multiple input voltage types (AC, DC, polarities) through a single integrated circuit design. The controlled switching network and capacitive energy transfer mechanism provide adaptability to various input conditions while maintaining consistent output performance, eliminating the need for separate converter designs for different input types.
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 eliminates power losses and EMI, reduces size and mass, and allows for flexible input and output voltage management, achieving efficient and cost-effective DC power conversion with minimal energy loss and EMI at resonant frequencies.
Implementation Method 1
complete transfer of the energy from a charged capacitor to a coil and then to a smaller capacitor
Data Source
AI summary
A device and a method for power conversion to DC using zero-current and/or zero-voltage switching. Provides output voltage of any level and polarity. Operates with any input voltage, including DC and AC. Power loss is substantially eliminated. The conversion efficiency is independent of load consumption, from the idle to the maximum power. The EMI level is very low. Provides for input to output isolation without use of transformers.