Brushless Variable Transformer Using Electronic Switching
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Solution Overview
Problem
Conventional variable transformers require maintenance and cleaning due to the use of brushes, which wear out from physical and electrical contact, making them impractical for applications requiring continuous voltage variation without mechanical issues.
Innovation Solution
A brushless variable transformer design utilizing electronic switches and unique circuitry to control voltage output, eliminating the need for brushes by using power switches and microcontrollers to manage current flow through inductive coupling between primary and secondary windings, allowing for continuous voltage adjustment without mechanical contact.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a sliding brush is used to contact winding turns for continuous voltage variation, then smooth voltage control is achieved, but the brush wears out from physical and electrical contact requiring maintenance
Solution Approach 1:
The patent replaces the mechanical sliding brush contact system with an electronic switching system using solid-state devices. Instead of physically sliding a brush over winding turns, the invention uses electronic switches (such as thyristors or transistors) to selectively connect different portions of the winding to the output, achieving continuous voltage control without mechanical wear.
Solution Approach 2:
The patent extracts and removes the brush component from the variable transformer system entirely. By eliminating the sliding brush, the invention removes the source of mechanical wear and maintenance requirements while preserving the core functionality of continuous voltage adjustment through electronic means.
2Ease of manufacture
If discrete taps are used on the winding, then voltage selection is simplified, but only discrete voltage levels are available rather than continuous variation
Solution Approach 1:
The patent transforms the static discrete tap system into a dynamic continuous control system. Instead of fixed connection points, the invention uses electronically controlled switches that can be adjusted continuously along the winding, enabling smooth voltage variation while maintaining the simplicity of a single winding structure.
Solution Approach 2:
The patent changes the control parameter from discrete tap positions to continuous electronic switching positions. By using solid-state switches with continuously adjustable firing angles or duty cycles, the system achieves continuous voltage control while retaining the manufacturing simplicity of a single winding with multiple connection points.
3Device complexity
If an autotransformer with a single winding is used, then device complexity is reduced, but electrical isolation between input and output is lost
Solution Approach 1:
The patent introduces electronic switching devices as intermediaries between the single winding and the output circuit. These solid-state switches provide electrical isolation while allowing control of voltage output, effectively mediating between the simple autotransformer structure and the requirement for electrical isolation.
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 provides a maintenance-free, reliable method for continuous voltage control and regulation, enabling smooth voltage variation from zero to above the input voltage, suitable for various applications, including testing and control systems, without the limitations of discrete taps or worn brushes.
Implementation Method 1
The primary core to which an input voltage is applied, through electromagnetic coupling induces a voltage across the secondary
Data Source
AI summary
A brushless variable transformer. Variable autotransformers, use brushes, and as such, have moving parts requiring maintenance and periodic cleaning of the brushes. A variable transformer without brushes is advantageous in that it eliminates the cleaning and maintenance of brushes.