Auxiliary Soft Switch Circuit for High-Frequency Power Supplies
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Solution Overview
Problem
Existing soft switch circuits are not adaptable to both isolated and non-isolated switching power supplies, leading to inefficiencies in switching loss reduction and increased switching frequency.
Innovation Solution
A soft switch circuit design that includes a switching voltage terminal, a main inductor, and an auxiliary module, which is connected in series between the switching voltage terminal and a first voltage terminal. The auxiliary module is configured to charge and discharge based on different level signals, reducing current flow through the switching voltage terminal and enabling 'soft' switching in both isolated and non-isolated power supplies.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a conventional soft switch circuit is used, then switching loss is reduced in either isolated or non-isolated power supplies, but the circuit cannot be adapted to both types of power supplies
Solution Approach 1:
The soft switch circuit is designed with a universal auxiliary module that can function in both isolated and non-isolated power supply configurations. The auxiliary module includes components (auxiliary inductor, switching tube, diode, capacitor) that can be connected in different configurations depending on whether the power supply is isolated or non-isolated, allowing the same basic circuit structure to achieve soft switching in both types of power supplies.
2Productivity
If switching frequency is increased, then power supply efficiency is improved, but switching loss increases
Solution Approach 1:
The auxiliary module performs preliminary action by pre-charging or pre-discharging the main switching tube's parasitic capacitor before the main switching event. This prepares the switching tube for soft switching, allowing high-frequency operation without proportionally increasing switching losses. The auxiliary circuit activates just before the main switch to ensure optimal switching conditions.
Solution Approach 2:
The auxiliary module acts as an intermediary between the input voltage and the main switching tube. It includes intermediate energy storage elements (auxiliary inductor, capacitor) that mediate the energy transfer process, enabling the main switch to operate at high frequencies while the auxiliary components handle the energy buffering and softening of switching transitions.
3Loss of energy
If an auxiliary module is added to reduce current through the switching voltage terminal, then switching loss is reduced, but device complexity increases
Solution Approach 1:
The auxiliary module is merged with the main switching circuit in a compact configuration. The auxiliary inductor can be wound on the same core as the main inductor, and the auxiliary switching tube shares the same voltage terminal connection points as the main switch. This merging reduces the overall space and component count while still achieving the current reduction and soft switching effects.
Solution Approach 2:
The auxiliary circuit components are nested within or around the main circuit components. For example, the auxiliary inductor is nested on the same magnetic core as the main inductor, and the auxiliary switching elements are positioned to share connection nodes with the main switching tube, creating a nested structure that minimizes additional complexity.
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 soft switch circuit effectively reduces switching losses and increases switching frequency, making it applicable to both isolated and non-isolated switching power supplies, thereby enhancing the efficiency and versatility of power supply systems.
Implementation Method 1
the auxiliary module is configured to be charged with a first voltage input from the first voltage terminal when the switching voltage terminal receives a first level signal
Implementation Method 2
a main inductor, and the auxiliary module is connected in series between the switching voltage terminal and the first voltage terminal
Data Source
AI summary
A soft switch circuit, comprising switch voltage end A, main inductor L and second voltage end B. Switch voltage end A is electrically connected to first end of main inductor L; and second voltage end B is electrically connected to second end of main inductor L. Soft switch circuit further comprises auxiliary module (100) and first voltage end C, wherein first end of auxiliary module (100) is electrically connected to switch voltage end A; and second end of the auxiliary module (100) is electrically connected to first voltage end C. Auxiliary module (100) is used for charging auxiliary module (100) by using first voltage input by means of first voltage end C; and auxiliary module is further used for performing discharging to the switch voltage end A. Further provided are a power source assembly comprising a soft switch circuit, and a method for controlling a soft switch circuit.