Center Tapped Transformer Winding Segmentation for Loss Reduction
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Solution Overview
Problem
Center tapped transformers in power conversion systems face challenges with high conduction losses and proximity losses due to bridge rectification and winding coupling, especially in converters with low output voltage but high output current, where existing designs fail to minimize these losses effectively.
Innovation Solution
A high frequency, double ended, isolated, push pull, center tapped power transformer is designed with two identical sets of windings where primary and secondary windings are tightly coupled within each set and loosely coupled between sets, using a magnetic field isolating separator to minimize proximity losses, and employing a bobbin-wound construction with subwindings for optimal coupling and leakage inductance adjustment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If bridge rectification is used on the secondary side, then the output voltage can be achieved, but conduction losses increase significantly in converters with low output voltage and high output current
Solution Approach 1:
The secondary winding is divided into two separate windings (Ns1 and Ns2) instead of using a single winding with bridge rectification. Each secondary winding is paired with its own primary winding (Np1 and Np2) to form independent transformer sets. This segmentation allows the use of center-tapped full-wave rectification on each side, reducing conduction losses while maintaining the required output voltage capability.
2Reliability
If the primary and secondary windings are placed abutting each other for tight coupling, then coupling coefficient is maximized, but leakage inductance increases
Solution Approach 1:
Each primary winding (Np1, Np2) is divided into two subwindings, allowing different portions of the winding to serve different functions. The subwindings are arranged to provide tight coupling where needed while managing leakage inductance characteristics locally, optimizing the balance between coupling coefficient and leakage inductance for each transformer set.
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
This design significantly reduces proximity losses and overall power losses, allowing for thicker wire usage and higher efficiency, achieving efficiency improvements of up to 0.5-0.7% over prior art transformers while maintaining low voltage spikes and cost-effectiveness.
Implementation Method 1
a magnetic field isolating separator placed in the space between said sets of windings
Implementation Method 2
The first primary winding is electromagnetically coupled to the first secondary winding. The second primary winding is electromagnetically coupled to the second secondary winding.
Data Source
AI summary
A cost effective solution for construction of high frequency, double ended, isolated, push pull, center tapped power transformers operating in continuous/discontinuous mode with minimized winding proximity losses comprises at least two identical sets of windings with identical coupling coefficients. Each set of windings consists of at least one primary winding and at least one secondary winding tightly coupled to each other. Both the sets of windings are loosely coupled to each other with a magnetic field isolating separator.