Flying-Capacitor DC-DC Converter for High-Voltage High-Power Scaling
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Solution Overview
Problem
Conventional DC-DC resonant converters struggle to simultaneously meet the demands of high input voltage and high-power applications.
Innovation Solution
The DC-DC converter employs pairs of flying capacitors and subcircuits, allowing for the adjustment of switching frequency to control the DC output voltage, suitable for high input voltage and high-power applications.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If conventional DC-DC resonant converter topology is used, then the structure is simple and efficiency is high, but it cannot simultaneously meet high input voltage and high-power application requirements
Solution Approach 1:
The converter is divided into multiple modular units, each containing a half-bridge circuit, flying capacitor, and resonant tank. These modular units can be stacked in series to achieve different voltage and power levels, allowing the system to scale for high-power applications while maintaining a standardized simple structure that can be replicated.
Solution Approach 2:
The patent introduces a vertical stacking dimension by connecting multiple converter modules in series, where each module contributes to the overall output voltage. This dimensional approach allows the system to achieve high voltage and power capabilities without fundamentally changing the basic converter topology, thus maintaining structural simplicity while enhancing adaptability.
2Stress or pressure
If the number of switching devices is increased to handle high input voltage, then the voltage handling capability is improved, but the device complexity and control difficulty increase
Solution Approach 1:
The voltage handling is segmented across multiple series-connected switching devices in each half-bridge module. Each switch only needs to withstand a portion of the total input voltage, reducing individual device stress. The modular architecture allows voltage scaling by simply adding more modules in series without complicating the switching configuration within each module.
3Stability of the object's composition
If flying capacitors are used to improve voltage distribution, then the voltage balance is improved, but the device complexity increases
Solution Approach 1:
The flying capacitors are merged with the resonant tanks to form integrated resonant-capacitive units. This combination allows the capacitors to serve dual purposes: voltage balancing across the series-connected modules and resonant energy storage. By merging these functions, the patent avoids adding separate voltage-balancing circuitry, thus improving voltage distribution stability without proportionally increasing device complexity.
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 converter effectively handles high input voltage and high-power applications by optimizing the connection of flying capacitors and subcircuits, enhancing its suitability for such demanding conditions.
Implementation Method 1
The resonant converter includes a resonant-tank circuit for shaping the switch voltage and/or the current waveform to minimize switching losses and allow high-frequency operation
Implementation Method 2
A n-th pair of the N pairs of flying capacitors is coupled between a common node between the n-th and (n+1)-th upper switches and a common node between the n-th and (n+1)-th lower switches
Data Source
Figure 1A
Figure 1B
Figure 2A
AI summary
A DC-DC converter (1, 1a, 1b, 1c, 1d, 1e, 1f) includes N upper switches (Sa1, Sa2, Sa3, ..., SaN), N lower switches (Sb1, Sb2, Sb3, ..., SbN), N pairs of flying capacitors (Ca1, ..., CaN, Cb1, ..., CbN) and N subcircuits (21, 22, 23, 24, ...). The N lower switches (Sb1, Sb2, Sb3, ..., SbN) are electrically connected between the N upper switches (Sa1, Sa2, Sa3, ..., SaN) and the second terminal of the voltage source (11). A n-th pair of flying capacitors (Ca1, ..., CaN, Cb1, ..., CbN) is coupled between a common node between the n-th and (n+1)-th upper switches (Sa1, Sa2, Sa3, ..., SaN) and a common node between the n-th and (n+1)-th lower switches (Sb1, Sb2, Sb3, ..., SbN). A N-th pair of flying capacitors (Ca1, ..., CaN, Cb1, ..., CbN) is coupled with the N-th upper switch (Sa1, Sa2, Sa3, ..., SaN) and the N-th lower switch (Sb1, Sb2, Sb3, ..., SbN). A first subcircuit (21) is coupled between a common node between the first upper switch (Sa1) and the first lower switch (Sb1) and a middle node of a first pair of flying capacitors (Ca1, Cb1). A i-th subcircuit (22, 23, 24, ...) is coupled between a middle node of a (i-1)-th pair of flying capacitors (Ca1, ..., CaN, Cb1, ..., CbN) and a middle node of a i-th pair of flying capacitors (Ca1, ..., CaN, Cb1, ..., CbN).