Linear Transformer Power Supply Saturation Mode
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Solution Overview
Problem
Off-line switching power supplies face challenges in protecting electronics from high voltage transients due to low input impedances, leading to higher fault currents and reduced reliability, especially when peak power requirements exceed typical capacities.
Innovation Solution
A linear transformer power supply design that includes a transformer with a primary and secondary winding, a rectifier, a capacitor, and a switch controlled by a controller to create a quasi-sinusoidal current, storing and releasing energy in the transformer's leakage reactances, optimizing energy transfer and reducing stress on components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If off-line switching power supplies are used to meet peak power requirements, then power delivery capability is improved, but protection from high voltage transients deteriorates due to low input impedances causing higher fault currents
Solution Approach 1:
The patent changes the operating parameters of the power supply by using a linear transformer operating in saturation mode rather than a high-frequency switching transformer. This parameter change allows the system to deliver peak power levels while maintaining high input impedance characteristics that provide inherent protection against voltage transients and reduce fault currents.
Solution Approach 2:
The patent converts the traditionally harmful effect of transformer saturation into a beneficial feature. By deliberately operating the linear transformer in saturation mode, the system achieves peak power delivery capability while the saturation effect itself provides current limiting and protection against voltage transients, turning what is usually considered a failure mode into a protective mechanism.
2Device complexity
If conventional full-wave rectifier power supplies are used, then circuit simplicity is improved, but energy extraction from transformer is worsened because filter capacitors only charge during brief intervals when transformer output voltage exceeds rectified DC voltage
Solution Approach 1:
The patent implements periodic action by using a controlled rectifier that operates in conjunction with the linear transformer's natural AC cycle. The controlled rectifier allows energy to be extracted during specific intervals of the AC cycle, synchronized with the transformer operation, thereby improving energy extraction efficiency while maintaining circuit simplicity.
Solution Approach 2:
The patent employs feedback control through the controlled rectifier to optimize energy extraction. The rectifier is controlled based on the transformer output voltage and load conditions, allowing maximum energy transfer during the intervals when the transformer can deliver power, thereby improving overall energy utilization without complicating the circuit architecture.
3Ease of manufacture
If linear transformers are used in conventional power supplies, then cost reduction and inherent transient protection are improved, but power delivery capability is worsened due to inability to meet peak power requirements above 2 watts
Solution Approach 1:
The patent changes the operating parameters of the linear transformer by operating it in saturation mode at the fundamental frequency rather than using high-frequency switching. This parameter change enables the linear transformer to deliver peak power levels above 2 watts while maintaining the cost advantages and inherent transient protection characteristics of linear transformer designs.
Solution Approach 2:
The patent introduces dynamic control through the controlled rectifier to enable the linear transformer to meet peak power requirements. The controlled rectifier dynamically adjusts the power transfer based on load demands, allowing the system to deliver peak power when needed while maintaining the simplicity and cost-effectiveness of linear transformer architecture.
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 solution effectively manages energy transfer across the entire AC cycle, reduces stress on components, and maintains a stable output voltage, enhancing reliability and efficiency while providing inherent isolation and unity power factor.
Implementation Method 1
causes energy to be stored in the primary and secondary leakage reactances of the transformer, and when in an open position, allows the stored energy in the primary and secondary leakage reactances to pass through the rectifier to the capacitor
Implementation Method 2
a transformer having a primary winding that receives an alternating current (AC) input voltage and a secondary winding which produces an AC output voltage
Data Source
AI summary
A linear transformer power supply is disclosed that extracts a high level of energy from a linear transformer during the full cycle of AC input voltage.