Isolated Resonant DC-DC Converter Control Below LC Resonance
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Solution Overview
Problem
Current DC-DC converters with galvanic isolation face challenges in efficiency and control due to high switching losses at high frequencies, particularly in integrated coreless transformer designs, which are essential for size reduction and safety in applications like industrial automation and medical equipment.
Innovation Solution
A DC-DC converter architecture that operates below the resonance frequency of the LC tank to maximize the quality factor, utilizing a synchronized rectifier and a regulation loop with a current generator module to control the resonant oscillator, and incorporating a central tap on both transformer windings to optimize magnetic flux and reduce resistive losses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If the converter operates at high frequencies to reduce transformer size, then the transformer area is reduced, but switching losses increase significantly
Solution Approach 1:
The patent changes the operating frequency parameter from high frequency to sub-resonant frequency (below the frequency that maximizes LC tank quality factor). This parameter change reduces switching losses in the analog circuit while maintaining acceptable transformer size through optimized magnetic core design and integrated coreless transformer architecture.
2Loss of energy
If the converter operates at resonance frequency to maximize quality factor, then efficiency is improved, but voltage spikes and dynamic variations increase
Solution Approach 1:
The patent applies preliminary anti-action by operating below the resonant frequency to preemptively avoid the harmful voltage spikes and high dv/dt effects that occur at resonance. The control loop and soft-start mechanism are designed to maintain stable operation in the sub-resonant region, preventing the occurrence of dangerous voltage peaks before they can develop.
3Area of stationary object
If integrated coreless transformer is used to reduce size, then area is reduced, but power losses increase
Solution Approach 1:
The patent changes the operating frequency parameter to sub-resonant frequencies where the integrated coreless transformer exhibits lower losses. The design optimizes the transformer geometry and magnetic material properties to compensate for the inherent losses of integrated coreless architecture, achieving acceptable efficiency despite the compact form factor.
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 approach reduces switching losses, enhances efficiency, and ensures safe energy management by controlling voltage spikes, thereby improving the overall performance and reliability of the converter while maintaining compact size and low power consumption.
Implementation Method 1
said resonant oscillator is configured to operate at a frequency below the resonance frequency of said resonant oscillator which maximizes the quality factor of the oscillator, in particular below the resonance frequency of a LC tank comprised in said resonant oscillator which maximizes the quality factor of said LC tank
Implementation Method 2
a DC-DC converter with galvanic isolation comprising a resonant oscillator coupled to a primary winding of a galvanic isolation transformer, a rectifier being coupled to a secondary winding of said galvanic isolation transformer
Data Source
AI summary
Provided is a DC-DC converter with galvanic isolation comprising a resonant oscillator coupled to a primary winding of a galvanic isolation transformer. A rectifier is coupled to a secondary winding of the transformer to provide an output voltage. The DC-DC converter comprises a regulation loop configured to regulate an output voltage with respect to a reference voltage by controlling a current flowing in the resonant oscillator as a function of a result of a signal indicative of the comparison between the output voltage and the reference voltage. The resonant oscillator is configured to operate at a frequency, in particular tuned at sub-resonant point, in particular sub-harmonic frequency, below a resonance frequency of the resonant oscillator which maximizes a quality factor of the resonant oscillator, in particular below a resonance frequency of a LC tank circuit comprised in the resonant oscillator which maximizes a quality factor of the LC tank circuit.