Planar Transformer Bridge Control for Secondary Current Balance
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing switching power supply devices face issues with current imbalance due to variations in the coupling coefficients of secondary windings to the primary winding of transformers, leading to inefficiencies and performance degradation.
Innovation Solution
A switching power supply device is designed with a planar transformer configuration, where two secondary windings are symmetrically disposed with respect to the primary winding, and the on-times of the primary side bridge switches are controlled differently to equalize the coupling coefficients, thereby eliminating current imbalance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If two secondary windings are coupled to one primary winding in a transformer, then power supply functionality is achieved, but variations in coupling coefficients occur leading to current imbalance
Solution Approach 1:
The patent applies parameter changes by adjusting the on-times of primary side bridge switches to compensate for variations in coupling coefficients. Specifically, when coupling coefficients between primary and secondary windings vary, the control device changes the on-time parameters of the switching elements to equalize secondary side voltages, thereby maintaining current balance despite manufacturing variations in coupling coefficients.
2Reliability
If additional balancing circuits are added to equalize coupling coefficients, then current imbalance is eliminated, but device complexity increases
Solution Approach 1:
The patent implements self-service by using the existing transformer and switching elements to achieve current balance through control parameter adjustment. The control device utilizes the already-present primary side bridge switches and adjusts their on-times to compensate for coupling variations, eliminating the need for additional balancing circuits or components while maintaining reliable current balance.
3Ease of manufacture
If symmetric winding configuration is used, then manufacturing is simplified, but coupling coefficient variations still occur
Solution Approach 1:
The patent applies asymmetry in the control parameters to compensate for the symmetric winding configuration. While the windings themselves are symmetric for ease of manufacture, the control device introduces asymmetric on-time adjustments for the primary side bridge switches based on detected coupling coefficient variations, thereby achieving precise current balance despite the symmetric physical structure.
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 configuration ensures balanced energy output from the secondary windings, improving efficiency and performance by reducing variations in secondary side inductance and eliminating the need for additional balancing circuits.
Implementation Method 1
a planar transformer... primary winding... secondary windings... coefficients of coupling the plurality of secondary windings to the primary winding
Data Source
AI summary
Provided is a switching power supply device in which coefficients of coupling a plurality of secondary windings to a primary winding of a transformer can be made equal, and current imbalance can be eliminated. The switching power supply device includes a planar type transformer, wherein a bridge, in which a plurality of switch elements are connected in series, and a primary winding is provided on a primary side of the transformer, and the switch elements include the switch elements controlled by a first on time, and the switch elements controlled by a second on time different from the first on time.