Transformer Current Balancing in Full Bridge Converters
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Solution Overview
Problem
Full bridge converters experience transformer saturation and circuit failure due to unbalanced current flow, leading to the accumulation of DC flux, which is not effectively addressed by existing technologies.
Innovation Solution
A method and circuit that balance current flow in a transformer by using a processor-controlled AC source and current sensors to monitor and adjust the duty cycles of the AC signal driving the transformer, ensuring equal current flow in both directions to prevent DC current accumulation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If PWM signal duty cycle is adjusted to control output voltage, then accurate voltage adjustment is achieved, but unbalanced current flow causes DC flux accumulation
Solution Approach 1:
The patent implements a feedback mechanism where the controller monitors the state of switches and adjusts the duty cycles of PWM signals dynamically. The current balancing network provides feedback through the inductor currents, allowing the controller to maintain balanced current flow in both directions while preserving accurate output voltage control.
Solution Approach 2:
The patent uses dynamic adjustment of duty cycles for different switches based on real-time current conditions. The controller dynamically modifies the PWM duty cycles to ensure that the current through the transformer primary is balanced in both directions, preventing DC flux accumulation while maintaining voltage control accuracy.
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 solution effectively balances the magnetic flux in the transformer, preventing transformer saturation and reducing the risk of circuit failure, while maintaining power efficiency and component reliability.
Implementation Method 1
The switching circuit generates an AC signal based on the DC voltage to drive the primary side of a transformer... The transformer may step the voltage up or down
Data Source
AI summary
Methods and circuits for balancing current in a transformer are disclosed herein. An embodiment of the method includes sensing the magnitude and direction of current flow through the primary side of the transformer. The magnitude of current flowing in a first direction is compared to the magnitude of current flowing in a second direction through the primary side of the transformer. An AC signal driving the primary side of the transformer is adjusted so that the current flow in the first direction is substantially the same as current flow in the second direction.