Self-excitation Push-pull Converter with Partial Magnetic Saturation
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Solution Overview
Problem
Self-excitation push-pull converters face inefficiencies with light loads, difficulty in increasing efficiency at rated loads, challenges with high input voltages, and limitations in increasing working frequency, along with current spikes that reduce converter efficiency.
Innovation Solution
The use of a magnetic core with a partial section that reaches saturation before the main section, allowing for reduced energy consumption and increased efficiency, while maintaining low losses, by employing a transformer with a magnetic ring having a main section and a thin partial section that can be made of the same or different materials, facilitating demoulding and winding processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a magnetic core with uniform cross-section is used in self-excitation push-pull converter, then the transformer can operate with sufficient inductance, but the converter efficiency is low especially with light loads due to excessive energy consumption during magnetic saturation
Solution Approach 1:
The magnetic core is segmented into two distinct sections: a main section with larger cross-sectional area and a partial section with smaller cross-sectional area. This segmentation allows the magnetic saturation to occur locally in the partial section rather than throughout the entire core, reducing the total energy consumption during saturation while maintaining sufficient inductance through the main section.
Solution Approach 2:
Different sections of the magnetic core are given different cross-sectional areas to serve different functions. The main section with larger area provides the necessary inductance and magnetic flux path, while the partial section with smaller area is designed to saturate first to trigger the push-pull oscillation. This local differentiation optimizes both efficiency and functionality.
2Productivity
If the working frequency of the converter is increased to improve power density, then the converter size can be reduced, but the losses increase and efficiency decreases
Solution Approach 1:
The magnetic core structure is designed to dynamically control the saturation process. By having a partial section that saturates first, the system can operate at higher frequencies while maintaining efficiency because the saturation occurs in a controlled manner in the partial section, reducing overall losses even at elevated frequencies.
3Loss of energy
If more turns are added to the transformer coils to increase inductance, then the converter efficiency improves, but the manufacturing complexity and production time increase
Solution Approach 1:
Instead of increasing the number of turns throughout the entire magnetic core, the invention achieves the necessary inductance by concentrating the magnetic path in the main section and allowing saturation in the partial section. This approach provides sufficient inductance with fewer turns, simplifying the winding process and reducing manufacturing complexity while maintaining efficiency.
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 substantially improves efficiency across all load ranges, reduces the number of turns on the transformer coils, allows for higher working frequencies, and minimizes current spikes, enabling efficient operation with higher input voltages and reduced production complexity.
Implementation Method 1
the magnetic core or iron core of the transformer has a partial section; the partial section can reach magnetic saturation before the main section with the same increasing magnetic field excitation
Data Source
AI summary
A self-excitation push-pull type converter with a transformer having a closed magnetic core or iron core, which formed of a main part (52) and a local part (53). The local part reaches magnetic saturation earlier than the main part under the same increasing magnetic field excitation. When the self-excitation push-pull type converter is in a light load state, the efficiency is significantly improved, and further improved in a rated load state. As the number of turns of the coil on the magnetic saturation transformer is reduced, the working frequency of the converter increases while still keeping the loss low. The probability of generating a current peak at the moments of switching on or off is reduced, thereby further improving the efficiency and reducing output ripples.