Bi-Directional DC-to-DC Converter Capacitor Segmentation
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Solution Overview
Problem
Conventional DC-to-DC converters face issues with uneven voltage sharing among capacitors, leading to over-voltage conditions and increased manufacturing costs due to the need for closely matched or higher voltage-rated capacitors, especially in high DC voltage applications.
Innovation Solution
A DC-to-DC converter design that uses first and second capacitors with lower voltage ratings, coupled with an inductor and switching devices, configured to form specific nodes for bi-directional operation, reducing the susceptibility to capacitor parameter variations and allowing for a higher output voltage rating while minimizing the need for high-voltage capacitors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a plurality of capacitors are implemented in series across voltage Vb to provide higher voltage rating, then the converter may be implemented in systems with high DC voltages, but parameter variations such as unmatched capacitances and leakage resistance result in uneven voltage sharing and over-voltage conditions
Solution Approach 1:
The converter is divided into two independent single-capacitor modules (first converter module and second converter module) instead of using a single multi-capacitor structure. Each module uses only one capacitor (Cb or Cc), eliminating the voltage sharing problem between multiple capacitors while maintaining the ability to handle high DC voltages through modular configuration.
2Reliability
If closely matched capacitors or capacitors with higher voltage ratings are used to limit over-voltage conditions, then the reliability improves, but the manufacturing cost increases
Solution Approach 1:
By segmenting the converter into independent modules each with a single capacitor, the patent eliminates the need for closely matched capacitors. Standard capacitors can be used in each module, significantly reducing manufacturing costs while maintaining reliable operation through the modular architecture that prevents voltage sharing issues.
Solution Approach 2:
The converter design uses universal, off-the-shelf capacitors that can be readily purchased from electronics distributors. The modular single-capacitor architecture allows the same capacitor type to be used across multiple modules, simplifying inventory and procurement while reducing the need for specialized, expensive matched capacitor sets.
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 effectively reduces the risk of over-voltage occurrences and decreases manufacturing costs by utilizing capacitors with lower voltage ratings, while maintaining a higher output voltage rating, thus enhancing the reliability and cost-effectiveness of the converter.
Implementation Method 1
The first switching device is configured to electrically couple the first and second terminals of the first switching device in response to a first control signal. Similarly, the second switching device is configured to electrically couple the first and second terminals of the second switching device in response to a second control signal.
Implementation Method 2
A DC-to-DC converter that transforms a lower input voltage into a higher output voltage (i.e., steps up the voltage) may be referred to as a 'boost' converter. Similarly, a DC-to-DC converter that transforms a higher input voltage into a lower output voltage (i.e., steps down the voltage) may be referred to as a 'buck' converter.
Implementation Method 3
The capacitors Ca and Cb of the conventional converter 10 are filter capacitors and the inductor La is a DC choke.
Data Source
AI summary
A DC-to-DC converter is provided and generally configured for implementation with an electric motor drive system. In at least one embodiment, the DC-to-DC converter includes first and second capacitors, an inductor, and first and second switching devices. The DC-to-DC converter is bi-directional to facilitate voltage transfer therethrough. In at least another embodiment, the electric motor drive system comprises an energy storage device, a drive unit, an electric motor and a bi-directional DC-to-DC converter. The energy storage device includes a positive and a negative terminal. The drive unit includes a first and second terminal. The electric motor is in electrical communication with the drive unit.