DC-DC Converter Input Filter Feedback for Oscillation Damping
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Solution Overview
Problem
Oscillations occur in DC-to-DC converters due to mismatched impedances between the input filter and power conversion circuit, leading to undesirable ripple voltage, which existing solutions either compromise performance or increase cost and size.
Innovation Solution
Utilize an auxiliary winding of the input filter's inductor to transfer feedback signals across the galvanic isolation barrier, allowing the voltage control loop to adjust the output voltage based on input filter output voltage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If additional damping components are added at the output of the input filter to reduce output impedance at resonant frequency, then oscillations are prevented, but cost and size of the converter increase
Solution Approach 1:
The auxiliary winding serves multiple functions: it provides feedback signaling across the galvanic isolation barrier and simultaneously acts as a damping mechanism by enabling the voltage control loop to reduce output impedance at resonant frequency. This eliminates the need for separate damping components.
Solution Approach 2:
The voltage control loop uses the feedback from the auxiliary winding to automatically adjust and reduce the output impedance at resonant frequency, making the system self-regulating without requiring external damping components. The system serves its own stabilization needs through intelligent control.
2Stability of the object's composition
If the voltage at the output of the input filter is used as feedback in the voltage control loop, then converter stability is improved, but signal transfer across galvanic isolation barrier becomes problematic
Solution Approach 1:
The auxiliary winding acts as an intermediary that enables signal transfer across the galvanic isolation barrier. It magnetically couples the input filter output voltage to the voltage control loop, allowing feedback without direct electrical connection and thus maintaining galvanic isolation while enabling stable control.
3Stability of the object's composition
If input filter components are carefully selected and converter response is tuned to avoid impedance mismatch, then oscillations are avoided, but performance of the converter is compromised
Solution Approach 1:
Instead of static component selection and fixed tuning, the system dynamically adjusts the output impedance at resonant frequency through the voltage control loop. The auxiliary winding provides real-time feedback that enables the converter to adapt its response characteristics, maintaining both stability and performance across varying operating conditions.
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
Stabilizes the converter by damping oscillations without increasing cost or size, maintaining performance by using the auxiliary winding to manage impedance mismatch.
Implementation Method 1
The present disclosure is directed to using an auxiliary winding of an inductor of the input filter to transfer the required signal across the galvanic isolation barrier
Data Source
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AI summary
In one embodiment, the present disclosure is directed to a DC-to-DC converter that includes an input filter. The inductor of the input filter has an auxiliary winding wound around the core element and not coupled to the input terminal. A voltage control circuit is configured to receive a first signal from the auxiliary winding of the inductor of the input filter, the first signal being indicative of an output voltage of the input filter. The voltage control circuit adjusts the desired output voltage level based on the first signal. An output terminal provides the adjusted desired output voltage level.