Non-Isolated Resonant DC-DC Control for Low-Loss Wide-Range Conversion
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Solution Overview
Problem
Existing non-isolated DCDC buck-boost converters suffer from high losses due to triangular wave currents, leading to increased conduction and harmonic wave losses.
Innovation Solution
A non-isolated DCDC resonant conversion control circuit with a series connection of an inductor and capacitor, utilizing a sine wave current and phase shift angle adjustment to enable zero voltage switching, combined with frequency adjustment for wide-range power and voltage control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If conventional buck-boost topology with triangular wave current is used, then the circuit can implement basic voltage conversion, but conduction loss and high-order harmonic loss increase significantly
Solution Approach 1:
The patent applies resonant vibration principles by introducing a resonant capacitor to create a series resonant circuit with the inductor. This transforms the triangular wave current into a sinusoidal current waveform, reducing high-order harmonic content and conduction losses while maintaining the buck-boost voltage conversion function.
Solution Approach 2:
The patent changes the current waveform parameter from triangular to sinusoidal by introducing resonant capacitance. This parameter change reduces the waveform coefficient from 1.11 (triangular) to 0.31 (sinusoidal), significantly lowering conduction losses and high-order harmonic losses.
2Loss of energy
If conventional critical continuous mode control is used, then switching transistors can achieve zero voltage switching, but peak current and turn-off current remain relatively large
Solution Approach 1:
The resonant circuit creates sinusoidal current flow that naturally reduces peak current stress compared to triangular waveforms. The resonant oscillation allows for softer current transitions, reducing both peak current and turn-off current while maintaining zero voltage switching capability.
3Loss of energy
If triangular wave current is used, then the circuit structure remains simple, but waveform coefficient is high leading to larger conduction loss
Solution Approach 1:
By introducing a resonant capacitor to create a series resonant circuit, the patent transforms the current waveform from triangular to sinusoidal. This adds only one component while achieving significant reduction in conduction losses through waveform optimization.
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
Significantly reduces conduction losses and enables efficient, wide-range DCDC conversion with zero voltage switching, enhancing efficiency and flexibility.
Implementation Method 1
the inductor and the capacitor that are resonant are connected in series
Data Source
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AI summary
According to a non-isolated DCDC resonant conversion control circuit provided in embodiments of this application, an inductor and a capacitor that are resonant are connected in series, so that a current flowing through the inductor is a sine waveform. A waveform coefficient of the sine wave is small, and a conduction loss is low. Therefore, the circuit provided in embodiments of this application can significantly reduce a circuit loss. According to the non-isolated DCDC resonant conversion control method provided in embodiments of this application, not only a phase shift angle can be adjusted to enable a switching transistor to implement zero voltage switching ZVS on, but switching frequency can also be adjusted. Therefore, ranges in which a voltage and power of an output interface can be adjusted are large, so that non-isolated wide-range DCDC resonant conversion is implemented.