Integrated Transformer PCB Infinity Winding for LLC Converter Losses
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Solution Overview
Problem
Magnetic losses, particularly core loss and winding loss, limit the efficiency of LLC resonant converters at high-switching frequencies, hindering the reduction of magnetic component sizes and increasing switching-related losses.
Innovation Solution
The use of integrated magnetic circuits with field-effect transistors (FETs) like GaN FETs and synchronous rectifier (SR) FETs, along with an infinity winding structure, reduces magnetic losses and minimizes transformer size by integrating windings and capacitors on a printed circuit board (PCB) to enhance thermal efficiency and reduce parasitic effects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If traditional magnetic components are used in LLC resonant converters, then the converter can provide isolation and voltage transformation, but core loss and winding loss increase at high-switching frequencies, limiting efficiency
Solution Approach 1:
The patent replaces traditional magnetic transformers with an integrated transformer circuit implemented on a PCB using conductive traces. This substitution eliminates magnetic core losses and winding losses associated with conventional magnetic components, enabling high-switching frequency operation with improved efficiency. The transformer functionality is achieved through planar spiral inductors and capacitive coupling structures fabricated on the PCB substrate.
Solution Approach 2:
The patent changes the operating parameters by designing the integrated transformer to operate optimally at high switching frequencies (above 100 kHz). The PCB-based implementation allows for precise control of parasitic parameters and enables operation in a frequency range where traditional magnetic components would suffer excessive losses, thereby improving overall converter efficiency.
2Power
If traditional magnetic components are used, then voltage transformation and isolation are achieved, but the magnetic component size limits power density
Solution Approach 1:
The patent replaces bulky magnetic transformers with a compact integrated transformer circuit fabricated on a PCB. The planar spiral inductors and capacitive coupling structures occupy minimal space compared to traditional magnetic components, enabling significant reduction in overall converter size and improvement in power density while maintaining voltage transformation and isolation functionality.
Solution Approach 2:
The patent transitions from three-dimensional magnetic core structures to two-dimensional planar PCB-based transformer structures. This dimensional change allows for more efficient space utilization and enables the integration of additional circuit functions within the same footprint, thereby increasing power density.
3Volume of stationary object
If higher switching frequencies are used to reduce component size, then power density increases, but switching-related losses increase
Solution Approach 1:
The patent replaces magnetic transformers with an integrated PCB-based transformer circuit that has minimal parasitic inductance and capacitance. This substitution reduces switching-related losses by eliminating magnetic core losses, eddy current losses, and winding resistance losses, allowing the converter to operate efficiently at high switching frequencies with reduced component sizes.
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 approach enables higher switching frequencies, reduces magnetic component sizes, and achieves high efficiency and power density in LLC resonant converters, suitable for high-performance applications like servers and telecommunications.
Implementation Method 1
a transformer secondary provides voltage to a secondary circuit
Data Source
AI summary
Apparatus providing an integrated transformer are disclosed. An example apparatus includes a power conversion system including a switching circuit including a first primary side transistor coupled between a first input node and a switching node, and a second primary side transistor coupled between the switching node and a second input node, a series circuit including a transformer primary winding, a capacitor, and an inductor coupled in series between the switching node and the second input node, a transformer secondary circuit including a first transformer secondary winding and a second transformer secondary winding, the first and the second transformer secondary windings electrically between a first converter output and a second converter output, the transformer primary winding and the transformer secondary windings wound around at least a portion of a corresponding one of a transformer core in an infinity winding arrangement.