Dual-Switch Forward Converter for Three-Phase Power Conversion
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Solution Overview
Problem
Conventional three-phase converters are costly due to the high expense of electronic switches, especially in systems requiring multiple converters for large-scale applications like wastewater disinfection using UV radiation, and existing flyback converter designs are inefficient for high-energy applications.
Innovation Solution
A forward converter design utilizing three transformers with two electronic switches and a diode-switch configuration to generate a galvanically isolated output voltage, minimizing components and optimizing efficiency, size, and cost, capable of powering multiple UV emitters or ozone generators effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional six-switch converters are used for three-phase conversion, then reliable power conversion is achieved, but cost increases significantly due to expensive electronic switches
Solution Approach 1:
The converter is divided into three independent single-phase conversion circuits, each handling one phase independently. This segmentation allows each circuit to use fewer switches (2 per phase instead of 6 total), reducing overall component count and cost while maintaining reliable conversion through distributed processing of the three-phase input
Solution Approach 2:
The three single-phase conversion circuits share common DC link capacitors and control infrastructure, allowing them to function as a unified three-phase converter system. This multi-functionality enables the simplified circuits to collectively achieve reliable three-phase to single-phase conversion without requiring dedicated components for each phase
2Device complexity
If flyback converter design with two power transistors is used, then component count is reduced, but efficiency becomes unfavorably low for high energy requirements
Solution Approach 1:
The converter operates by periodically switching the two electronic switches in synchronization with the three-phase input voltage cycles. This periodic switching enables continuous energy transfer from the input to output through the transformers and capacitors, maintaining high efficiency while using fewer components through rhythmic energy storage and release cycles
Solution Approach 2:
Transformers are introduced as intermediary energy transfer elements between the electronic switches and the load. These transformers provide galvanic isolation and enable efficient energy transfer with minimal losses, allowing the system to achieve high efficiency with reduced component count by using magnetic coupling instead of direct electrical connection
3Productivity
If multiple converters are deployed for large-scale UV disinfection systems, then adequate power coverage is achieved, but total cost increases due to repeated use of expensive electronic switches
Solution Approach 1:
Multiple single-phase conversion circuits are merged into a unified three-phase converter system that processes all three phases simultaneously. This combining approach provides adequate power coverage for large-scale applications while reducing total system cost by eliminating redundant switches that would be required if separate converters were used for each phase
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 significant cost advantages and improved efficiency for powering low-pressure lamps and ozone generators, reducing electrical losses and converter costs compared to conventional systems.
Implementation Method 1
The primary side of the converter is connected to a three-phase input voltage U1, U2 and U3. The secondary area, which is galvanically decoupled via transformers T1, T2 and T3
Data Source
Figure 1
Figure 2~3
Figure 4
AI summary
The invention relates to a current converter of the forward converter type for converting a three-phase primary voltage (U1, U2, U3) into a plurality of secondary voltages (ud1... udn), having a magnetic intermediate circuit that comprises at least three transformer secondary windings (7, 8, 9), wherein the current converter, on the primary side thereof, has at least three transformers (T1, T2, T3), each having two primary windings (1,2; 3,4; 5,6;) which are wound in opposite directions and at least one secondary winding (7, 8, 9), and two electronic switches (S1, S2) are provided, wherein the first switch (S1) in each case controls a primary winding (1, 3, 5) of the three transformers (T1, T2, T3) via a set of diodes (D1. 1... D1.6), and wherein the second switch (S2) in each case controls another primary winding (2, 4, 6) of the three transformers (T1, T2, T3) via a second set of diodes (D2.1... D2.6).