Partial-Resonant 3-Level Buck Converter for Low-Voltage Efficiency
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Solution Overview
Problem
Buck converters face challenges in efficiently managing inductor current when the input voltage is low compared to the output voltage, leading to reduced power conversion efficiency and difficulties in achieving optimal operations due to element deviations.
Innovation Solution
A DC/DC converter with a 3-level buck converter structure utilizes partial resonance to increase the inductor current before a resonant period, incorporates an interleaving technology to counterbalance inductor current ripple, and includes a coupled inductor to optimize inductor current peak and slope.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the switching frequency is increased to reduce inductor size, then the inductor size decreases, but the power conversion efficiency deteriorates
Solution Approach 1:
The patent applies resonance by utilizing the natural oscillation of the LC circuit at a specific frequency. By operating the converter at or near the resonant frequency of the inductor and capacitor combination, the system achieves soft switching conditions that reduce switching losses while maintaining efficient power transfer, thereby avoiding the efficiency deterioration that would normally occur with high-frequency operation
Solution Approach 2:
The patent changes the operating parameters by using variable switching frequencies that adapt to the load conditions and voltage ratios. The controller adjusts the switching frequency dynamically to maintain optimal efficiency across different operating points, allowing the system to achieve both small inductor size and high power conversion efficiency
2Loss of energy
If a 3-level hard switching buck converter is used, then the efficiency is improved, but the switching frequency cannot be increased and inductor size cannot be reduced
Solution Approach 1:
The patent transitions from hard switching to soft switching by utilizing resonance. The LC resonant circuit creates oscillating currents and voltages that enable zero-voltage or zero-current switching, eliminating the hard switching losses while allowing for higher frequency operation and smaller magnetic components
Solution Approach 2:
The patent introduces dynamic control mechanisms where the switching frequency and duty cycle are continuously adjusted based on real-time operating conditions. This dynamic adaptation allows the converter to maintain high efficiency across varying load conditions while operating at frequencies that enable reduced inductor and capacitor sizes
3Volume of moving object
If a 3-level resonant buck converter is used, then the switching frequency can be increased and inductor size reduced, but accurate LC resonance requires specific voltage ratio conditions that may not be met in actual use
Solution Approach 1:
The patent employs dynamic frequency and duty cycle adjustment that adapts to varying voltage ratios and load conditions. The controller continuously monitors operating parameters and modifies the switching strategy to maintain resonance or near-resonance conditions across a wide range of voltage ratios, eliminating the rigid voltage ratio requirements of traditional resonant converters
Solution Approach 2:
The patent segments the switching operation into multiple phases or modes that can be independently controlled. This segmentation allows the converter to handle different voltage ratio scenarios by switching between appropriate operating modes, thereby achieving both resonance benefits and wide adaptability
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 proposed solution enhances power conversion efficiency, allows for higher switching frequencies, and reduces the size of the DC/DC converter by using small inductance and capacitance values, while also decreasing conductive losses.
Implementation Method 1
partial resonance is used to increase the inductor current before a resonant period
Data Source
AI summary
A direct current (DC)/DC converter is provided. The DC/DC converter includes multiple switches, a capacitor, an inductor, and at least one processor, wherein, when the output voltage of the DC/DC converter is less than a first threshold voltage, the at least one processor is configured to control an on/off state of the multiple switches so as to increase the current output from the inductor based on the current, which is output from the inductor, being less than a first threshold current, and control a second switch and a fourth switch to be in an on state or control a first switch and a third switch be in the on state to allow one end or the other end of the capacitor to be connected to one end of the inductor, based on the current, which is output from the inductor, being increased to be greater than or equal to the first threshold current.