Capacitor-Switched AC-AC Converter for Transformerless Voltage Step-Down
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing AC-AC voltage transformation systems rely on traditional transformers, which are costly and inefficient, and switching converters are complex and expensive.
Innovation Solution
An AC-AC converter circuit utilizing capacitors and high-frequency switches, such as thyristors, to step down voltage without transformers, employing principles of DC-DC converters to achieve efficient and stable voltage regulation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If traditional transformers are used for AC-AC voltage transformation, then voltage transformation is achieved, but cost and efficiency are reduced
Solution Approach 1:
The patent replaces the traditional electromagnetic transformer system with a switching converter system that uses electronic components (switches, capacitors, inductors) to achieve voltage transformation. This substitution of mechanical/electromagnetic system with electronic system improves efficiency and reduces cost while maintaining the voltage transformation function.
Solution Approach 2:
The patent changes the operating parameters by using high-frequency switching (e.g., 100 kHz) instead of traditional power frequency (50/60 Hz) operation. This parameter change enables the use of smaller magnetic components and reduces losses, thereby improving efficiency and reducing the size and cost of the transformation system.
2Productivity
If switching converters are used for voltage conversion, then voltage transformation is achieved, but device complexity and cost increase
Solution Approach 1:
The patent divides the switching converter into modular sections with standardized components (input capacitor, switching stage with thyristors, output inductor, output capacitor). This segmentation allows for easier design, manufacturing, and maintenance while reducing overall complexity through modularity.
Solution Approach 2:
The patent designs the switching converter with universal components that can handle both step-down and step-up voltage conversion by changing the switching duty cycle. The same basic circuit topology serves multiple functions, reducing the need for separate circuits for different conversion modes and thereby reducing overall complexity.
3Reliability
If traditional transformers are used, then galvanic isolation is provided, but cost and efficiency are reduced
Solution Approach 1:
The patent uses capacitors and inductors as intermediary energy storage elements that provide galvanic isolation between input and output circuits while allowing efficient energy transfer. The capacitive and inductive coupling acts as an intermediary that maintains isolation without the losses associated with traditional transformer magnetic coupling.
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 circuit provides cost-effective and efficient voltage transformation by eliminating the need for traditional transformers, improving voltage regulation and reducing costs compared to existing systems.
Implementation Method 1
The circuit also includes a first and a second capacitor in parallel with the input and output
Implementation Method 2
The circuit also includes a first and a second inductor in series with the input and the output
Data Source
AI summary
A circuit for stepping down an alternating current (AC) voltage from an input voltage to an output voltage. The circuit includes an input configured to couple to a voltage source for providing the input voltage as an AC signal to the circuit. The circuit also includes a first and a second capacitor in parallel with the input and an output. The circuit further includes a first and a second inductor in series with the input and the output. Additionally, the circuit includes a first switch in series with the input and the output and a second switch, wherein the output voltage of the circuit provided to the output is an AC signal that is less than or equal to the input AC signal based on a duty cycle of the first switch.