Inverter Switch Leg Control for Lower High-Frequency Switching Loss
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Solution Overview
Problem
Existing power converter designs face inefficiencies due to 'hard' switching methods, which result in significant switching losses, especially at high switching frequencies. These losses reduce energy conversion efficiency and increase power loss peaks in switches.
Innovation Solution
The proposed AC/DC converter circuit incorporates a switching leg configuration with multiple switches connected in series, allowing for dynamic and static voltage blocking. This configuration includes auxiliary switches that help reduce switching losses by shifting them to the auxiliary switches while maintaining the majority of current flow through main switches.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If hard switching method is used in power converter, then the converter can operate at high switching frequency, but switching losses increase significantly causing reduced energy conversion efficiency
Solution Approach 1:
A resonant inductor is introduced as an intermediary element between the power source and load. This inductor creates a resonant circuit that enables the current to continue flowing during switching transitions, thereby softening the switching action and reducing switching losses while maintaining high switching frequency operation
Solution Approach 2:
The switching strategy is made dynamic by continuously monitoring the current flow and adjusting the switching timing accordingly. The system dynamically switches between different operating modes (hard switching and soft switching) based on real-time conditions, optimizing efficiency while maintaining productivity
2Strength
If multiple switches are connected in series to increase voltage blocking capacity, then the voltage handling capability increases, but the device complexity and synchronization difficulty increase
Solution Approach 1:
The high voltage blocking requirement is segmented across multiple switches connected in series. Each switch handles a portion of the total voltage, allowing the use of lower-voltage-rated, more efficient switches while achieving the required overall voltage blocking capacity
Solution Approach 2:
Not all switches in the series connection need to switch simultaneously. The system uses partial switching where only certain switches are activated during specific operating conditions, reducing the synchronization complexity while maintaining adequate voltage blocking capability
Data Source
AI summary
A power system may include a plurality of power sources and an inverter. The inverter may include a controller and a switch leg with one or more switches. The controller may control the inverter to convert direct current (DC) power generated by the plurality of power sources into alternating current (AC) power by variously controlling the switches of the switch leg during first and second time periods of a power cycle.