Modular Switched-Capacitor DC Supply for High Step-Down Conversion
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Solution Overview
Problem
Existing power electronic solutions for medium-voltage direct-current systems face challenges in achieving high step-down ratios with low cost, complex control strategies, high drive and output isolation requirements, and lack of self-powering ability, making them unsuitable for low-power applications.
Innovation Solution
A switched-capacitor type modular direct-current power supply with a high step-down ratio, utilizing standardized submodule circuits in a hierarchical manner, where each submodule includes an independent control module and switch transistors with low voltage stress, enabling asynchronous operation and self-powering without a central controller.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stress or pressure
If semiconductor devices are directly connected in series to achieve medium-voltage operation, then voltage level capability is improved, but gate control complexity and synchronization requirements worsen
Solution Approach 1:
The power supply system is divided into multiple independent submodule circuits connected in series, where each submodule contains its own switch transistors and capacitors. This segmentation allows each module to operate independently with simplified control, while the series connection achieves the required medium-voltage level capability.
Solution Approach 2:
Each submodule circuit is designed to be self-contained with independent control capabilities. The modules can autonomously manage their own switching operations and voltage distribution without requiring complex centralized synchronization control, thereby reducing overall system control complexity.
2Stress or pressure
If modular power supply cascade technologies are used to achieve medium-voltage operation, then voltage level capability is improved, but voltage sharing control complexity worsens
Solution Approach 1:
The system implements voltage sharing control through feedback mechanisms where the operating state of switch transistors in each module is adjusted based on voltage feedback. This ensures automatic voltage distribution across series-connected modules without requiring complex centralized coordination.
Solution Approach 2:
Each submodule circuit independently manages its own voltage sharing through local control based on voltage feedback, eliminating the need for complex inter-module communication and centralized voltage sharing control.
3Power
If input-series output-parallel converter configuration is used, then high step-down ratio is achieved, but input voltage sharing effect deteriorates as modules increase
Solution Approach 1:
The system uses voltage feedback to dynamically adjust the operating state of switch transistors in each module, ensuring effective input voltage sharing even as the number of modules increases. This feedback mechanism compensates for the deterioration effect observed in conventional ISOP converters.
4Power
If conventional modular power supply solutions are used, then voltage transformation capability is improved, but system structure complexity worsens
Solution Approach 1:
The power supply is segmented into standardized submodule circuits that can be independently designed, analyzed, and manufactured. Each submodule contains identical circuit topologies with switch transistors, capacitors, and diodes, simplifying the overall system structure through repetition of proven designs.
Solution Approach 2:
The submodule circuits are designed with universal characteristics where each module can function independently and interchangeably. The standardized design allows modules to be universally applied in series configurations to achieve different voltage levels without requiring module-specific control logic.
5Measurement precision
If centralized control is implemented for voltage sharing, then voltage distribution accuracy is improved, but control system complexity worsens
Solution Approach 1:
The system implements voltage distribution control through decentralized feedback mechanisms where each module independently adjusts its switch transistor operating state based on local voltage feedback, achieving accurate voltage distribution without complex centralized control.
Solution Approach 2:
Control functionality is segmented and distributed to individual modules rather than centralized. Each submodule circuit possesses independent control capabilities, eliminating the need for complex centralized control systems while maintaining accurate voltage distribution through local feedback loops.
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 power supply achieves flexible expansion, low-cost implementation, and efficient voltage sharing between capacitors with soft switching operations, suitable for medium-voltage and high-voltage direct-current inputs, and operates independently without complex central control.
Implementation Method 1
an auxiliary transformer... The auxiliary transformer is used for the control module to obtain power
Data Source
AI summary
A switched-capacitor type modular direct-current power supply with a high step-down ratio includes an upper modular cascade circuit string and/or a lower modular cascade circuit string, a load, and an input source. The upper and lower modular cascade circuit strings respectively include i upper submodule circuits and j lower submodule circuits. All the submodule circuits are non-isolated three-port resonant switched-capacitor circuits including input and output capacitors connected in series. The power supply is formed, by modular cascades, into a high-step-down-ratio direct-current power supply having high voltage direct-current input and low voltage direct-current output. Combination modes of modules include cascading of upper module strings, cascading of lower module strings, and mixed cascading of the upper and lower module strings. Flexible expansion can be performed based on voltage and power class requirements, without involving any voltage or current measurement apparatus.