Tri-Active Bridge Converter Control for Core Saturation and Losses
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Solution Overview
Problem
High-power applications of power converter circuits face challenges such as ripple currents, high voltage differentials, and magnetic core saturation, which are not effectively addressed in smaller converters.
Innovation Solution
A multi-level switching power converter system with a tri-active bridge module and a transformer assembly that includes a magnetic element to divert magnetic flux, using a switch controller to adjust switching signals for frequency and phase to mitigate saturation and reduce switching losses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If conventional power converter circuits are used in high-power applications, then voltage and current conversion is achieved, but magnetic core saturation occurs and switching losses increase
Solution Approach 1:
The patent divides the single power converter circuit into multiple parallel power converter circuits, each handling a portion of the total power. This segmentation prevents any single magnetic core from experiencing saturation by distributing the magnetic flux load across multiple cores, while maintaining the required high power conversion capability.
Solution Approach 2:
The patent introduces a controller as an intermediary that coordinates the operation of multiple power converter circuits. The controller adjusts switching signals to balance the load distribution among parallel circuits, preventing magnetic core saturation while achieving the desired power conversion.
2Power
If conventional power converter circuits are used in high-power applications, then voltage and current conversion is achieved, but switching losses increase
Solution Approach 1:
The patent segments the power conversion function across multiple parallel circuits, which reduces the switching burden on each individual circuit. This segmentation allows for optimized switching patterns that minimize switching losses while maintaining the required high power conversion capability.
Solution Approach 2:
The patent employs periodic switching patterns in the parallel power converter circuits, where switching events are distributed over time rather than concentrated. This periodic action reduces peak switching losses and improves overall efficiency in high-power applications.
3Device complexity
If single power converter circuit is used, then circuit simplicity is maintained, but ripple currents and voltage differentials become problematic
Solution Approach 1:
The patent divides the power conversion function into multiple parallel circuits, which naturally distributes and reduces ripple currents through the transformer. Each circuit handles a portion of the total current, preventing excessive ripple and voltage differentials that would occur in a single high-power circuit.
Solution Approach 2:
The patent combines multiple parallel power converter circuits to achieve the desired power handling capability. By merging the outputs of multiple circuits with reduced individual ripple currents, the system achieves low total ripple current while maintaining relatively simple circuit configurations.
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 system efficiently manages high voltages and currents, minimizing transformer saturation and switching losses, and eliminates the need for bulky resonant components, enhancing efficiency and reducing component size.
Implementation Method 1
a magnetic element coupled to the magnetic core and formed from a second material different from the first material of the magnetic core. The magnetic element can be configured to divert a portion of magnetic flux from the magnetic core of the transformer
Implementation Method 2
a sense coil magnetically coupled to the magnetic element and configured to provide a feedback signal that is indicative of saturation of the magnetic core of the transformer
Implementation Method 3
A first switching stage includes a first set of switches arranged as a first H-bridge and controlled by a first set of switching signals to convert between an AC voltage and a first DC voltage
Data Source
AI summary
One example includes a TAB switching converter that includes a transformer, a first switching stage, a second switching, and a third switching stage to convert between a DC voltage and an AC voltage. Switching nodes of the second and third switching stages can be directly coupled to respective first and second windings of the transformer. The system further includes a switch controller configured to generate switching signals at a variable frequency that varies as a function of a power metric associated with a frequency of the AC voltage, and to provide a variable phase shift between the respective switching signals that control one switch in each of pairs of switches in at least one of the second and third switching stages relative to another one switch in each of the pairs of the respective at least one of the second and third switching stages.