Coupled Two-Stage Inductor Power Converter for High Step-Down Ratio
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Solution Overview
Problem
Single-stage power converter systems with high step-down ratios suffer from poor accuracy, stability, and noise susceptibility, leading to decreased efficiency and increased costs due to expensive control units.
Innovation Solution
A power converter system utilizing a common switch to operate two power converting units in-phase and synchronously, integrating a coupled two-stage inductor to enhance step-down ratio and efficiency while reducing costs and volume.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single-stage power converter system with high step-down ratio is used, then the circuit structure is simple, but the duty ratio of switch decreases leading to poor accuracy and stability
Solution Approach 1:
The single-stage power converter is segmented into two cascaded stages: a first power converting unit and a second power converting unit. Each stage operates with its own switch (SW1 and SW2) and controlling unit, allowing independent optimization of duty ratios. This segmentation resolves the contradiction by maintaining circuit simplicity while improving accuracy and stability through multi-stage conversion with optimized duty cycles for each stage.
2Device complexity
If a single-stage power converter system with high step-down ratio is used, then the circuit structure is simple, but the system is susceptible to noise interference decreasing power conversion efficiency
Solution Approach 1:
The power conversion process is divided into two stages with intermediate energy storage capacitors (C1 and C2). Each stage operates at optimized duty ratios, reducing current ripple and electromagnetic interference. The intermediate capacitors act as noise filters between stages, improving overall power conversion efficiency while maintaining relatively simple circuit structure.
3Reliability
If a dual-stage power converter system is used to improve accuracy and stability, then the conversion efficiency improves, but the cost and volume increase
Solution Approach 1:
The first and second power converting units share common components including input capacitor Cin, output capacitor Cout, and diodes D1 and D2. The inductors L1 and L2 are integrated into a coupled two-stage inductor structure. This merging of components achieves dual-stage conversion functionality while reducing overall component count, cost, and volume compared to completely separate dual-stage systems.
Solution Approach 2:
The controlling units are designed to simultaneously control both switches SW1 and SW2, enabling coordinated operation of both power converting units. The shared capacitors and diodes serve multiple functions across both stages. This multi-functionality approach maintains improved accuracy and stability while reducing system complexity, cost, and volume.
4Loss of energy
If multiple switches are used in dual-stage power converter, then the power conversion efficiency improves, but the cost increases
Solution Approach 1:
The first and second power converting units share common diodes D1 and D2, reducing the total number of active components. The coupled two-stage inductor integrates L1 and L2 into a single magnetic structure. These merging strategies reduce component count and cost while maintaining the efficiency benefits of dual-stage conversion with optimized duty ratios for each stage.
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 solution significantly increases the step-down ratio, improves conversion efficiency by over 10%, and reduces costs and volume by more than 30% and 40% respectively, compared to existing dual-stage systems.
Implementation Method 1
The first coil is winded on the first cylinder and the fourth cylinder. The second coil is winded on the second cylinder and the fifth cylinder.
Data Source
Figure 1
Figure 2A~2B
Figure 2C~2D
AI summary
A power converter system and a coupled two-stage inductor are provided. The power converter system includes a first power converting unit, a second power converting unit and a common switch. The first power converting unit includes a first inductor and a first capacitor. The first inductor is electrically connected to the first capacitor. The second power converting unit includes a second inductor and a second capacitor. The second inductor is electrically connected to the second capacitor. The common switch is electrically connected to the first power converting unit and the second power converting unit. The first power converting unit and the second power converting unit are both operated with the common switch. When the common switch is conducted, the first power converting unit and the second power converting unit perform a two-stage power converting procedure with in-phase and same time sequence.