Resonant Buck Circuit for High Step-Down With Lower Switching Loss
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Solution Overview
Problem
Existing buck circuits face challenges in achieving a large proportion of buck transformation efficiently, leading to increased cost and reduced energy conversion efficiency when using multi-stage transformations.
Innovation Solution
A buck circuit design incorporating resonant elements and auxiliary switching elements in parallel with a main switching element and inductor, allowing for zero-voltage switching and adjusted duty cycles to enhance buck transformation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If multi-stage transformations are used to achieve large proportion of buck transformation, then the buck transformation ratio is improved, but the device complexity and cost increase
Solution Approach 1:
The circuit segments the buck transformation process into two distinct phases: a first phase where the main switching element operates alone, and a second phase where the auxiliary switching element operates in conjunction with resonant elements. This segmentation allows each component to perform specialized functions, achieving high transformation ratio without requiring multiple complete buck stages.
Solution Approach 2:
The circuit dynamically switches between different operating modes by controlling the main and auxiliary switching elements with opposite duty cycles. The main switching element operates with duty cycle D1 while the auxiliary switching element operates with duty cycle D2, where D1 + D2 = 1. This dynamic operation enables flexible adjustment of the overall buck transformation ratio.
2Power
If multi-stage transformations are used to achieve large proportion of buck transformation, then the buck transformation ratio is improved, but the energy conversion efficiency decreases
Solution Approach 1:
The circuit employs resonant oscillation involving resonant inductors and resonant capacitors during the second phase operation. This resonance enables zero-voltage switching for the auxiliary switching element, eliminating switching losses and significantly improving energy conversion efficiency while maintaining high buck transformation ratio.
Solution Approach 2:
The circuit changes the operating parameters of switching elements by controlling their duty cycles oppositely. The main switching element uses duty cycle D1 and the auxiliary switching element uses duty cycle D2, where D1 + D2 = 1. This parameter adjustment optimizes the transformation ratio while minimizing energy losses through efficient switching timing.
3Power
If the main switching element duty cycle is increased to achieve larger buck effect, then the buck transformation ratio is improved, but the switching losses increase
Solution Approach 1:
Instead of simply increasing the main switching element duty cycle, the circuit inverts the approach by introducing an auxiliary switching element that operates with an opposite duty cycle. When the main switching element has duty cycle D1, the auxiliary switching element has duty cycle D2 where D1 + D2 = 1. This inversion allows the system to achieve high transformation ratio while the auxiliary element operates under resonant conditions that minimize switching losses.
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 design achieves a larger proportion of buck transformation with reduced switching losses and improved energy conversion efficiency, particularly suitable for low voltage and high current output applications.
Implementation Method 1
controlling, at a second time, the auxiliary switching element to be in an on state and the main switching element to be in an off state, so that a resonant capacitor and a resonant inductor in a resonant element generate resonance
Data Source
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AI summary
Embodiments of the present application provide a buck circuit, a buck circuit control method, device and system. The buck circuit comprises: a main switching element and an inductor that are connected at a voltage input end and a voltage output end, wherein resonant elements are disposed in series between the main switching element and the inductor, the resonant elements and the inductor are further provided with auxiliary switching elements in parallel, the inductor is provided in parallel with a switching tube, one end of the switching tube is grounded, and the other end of the switching tube is connected between the resonant element and the inductor, wherein an on-off state of the auxiliary switching element is opposite to that of the main switching element. The present application can achieve a larger proportion of buck effect.