Multi-Stage Buck Converter for High Power Density With Lower Switching Loss
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Solution Overview
Problem
Conventional buck converters face challenges in increasing power density while minimizing switching loss and heat generation, as higher switching frequencies lead to resonance issues and component burnout due to parasitic characteristics.
Innovation Solution
A multi-stage buck converter design featuring a capacitor string and power switch module with N power switch groups, where the working frequency of the power conversion module is N times the switching frequency of each power switch group, allowing for efficient charging and discharging of an energy storage element, reducing switching loss, and enhancing power density.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the switching frequency of the power switch is increased to increase power density, then the power density is improved, but the switching loss and heat generation increase
Solution Approach 1:
The patent divides the power conversion process into multiple stages with N power switch groups operating in sequence. Each power switch group operates at a lower switching frequency, but the cumulative effect of N stages achieves the desired power density. This segmentation allows the system to benefit from high power density while avoiding the switching loss penalties of a single high-frequency switch.
2Power
If the switching frequency of the power switch is increased to increase power density, then the power density is improved, but the heat generation increases (limited power supply capacity)
Solution Approach 1:
By segmenting the power conversion into N stages with multiple power switch groups, each operating at a lower frequency, the patent distributes the heat generation across multiple components rather than concentrating it in a single high-frequency switch. This enables better thermal management and maintains higher power supply capacity.
3Power
If the switching frequency is increased to increase power density, then the power density is improved, but high-frequency signals resonate with parasitic characteristics causing component burnout and system instability
Solution Approach 1:
The patent changes the operating parameters by using N power switch groups each operating at a lower switching frequency, such that the working frequency of the power conversion module is N times the switching frequency of each power switch group. This parameter transformation allows the system to achieve high power density equivalent to a single high-frequency switch while operating in a mid-low frequency range that avoids resonance with parasitic characteristics, thereby improving reliability and system stability.
Data Source
AI summary
A multi-stage buck converter is provided. The multi-stage buck converter includes a capacitor string, a power switch module and a power conversion module. The capacitor string includes N capacitors connected in series. The power switch module is coupled to the capacitor string and includes N power switch groups. The power conversion module is coupled to the power switch module and includes an energy storage element. Wherein a working frequency of the power conversion module is equal to N times of the switching frequency of each of the N power switch groups, and N is a positive integer greater than or equal to 2. Wherein the working frequency is the number of times of the energy storage element that completes charging and discharging in a unit time.