Multi-Bridge AC Power Converter for Voltage Regulation
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Solution Overview
Problem
Existing power converter systems for AC mains power supply face challenges in efficiently addressing voltage regulation, voltage sag, and surge correction, particularly in large power loads, due to the need for significant magnetic components and semiconductors, which can be economically and energetically inefficient.
Innovation Solution
A multi-bridge power converter system utilizing passive or active rectifiers with novel switching algorithms and energy storage elements, which reduces the size of magnetic components and semiconductors by maintaining a DC bus voltage at half that of prior art, while employing thyristors and active rectifiers for enhanced efficiency and flexibility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional power converter systems are used for AC mains power supply, then voltage regulation and surge correction can be achieved, but the system requires significant magnetic components and semiconductors, increasing size, cost, and energy loss
Solution Approach 1:
The patent divides the conventional single-bridge power converter into multiple smaller bridge circuits (first bridge circuit, second bridge circuit, third bridge circuit, fourth bridge circuit) connected in parallel. Each bridge handles a portion of the total power load, allowing the magnetic components and semiconductors in each bridge to be significantly smaller than those required in a conventional single-bridge system handling the same total power. This segmentation directly resolves the contradiction by maintaining voltage regulation capability while reducing component size.
Solution Approach 2:
The patent combines multiple bridge circuits with identical or similar functionality into a unified parallel configuration, all operating under a common control scheme. The bridges share common DC bus connections and are coordinated by a central controller that monitors and regulates the combined output. This merging approach maintains the reliability and voltage regulation of conventional systems while distributing the power handling across smaller components, thereby reducing overall component size and energy losses.
2Power
If conventional power converter systems are used for AC mains power supply, then power conversion can be achieved, but the system incurs significant energy losses due to large magnetic components and semiconductors
Solution Approach 1:
By segmenting the power conversion function across multiple parallel bridge circuits, each operating at a lower power level, the system reduces energy losses in each individual component. Smaller magnetic components have lower core and copper losses, and smaller semiconductors have lower conduction and switching losses. The cumulative effect across all bridges achieves the required total power conversion with significantly lower overall energy losses compared to a single large-bridge system.
Solution Approach 2:
The patent changes the operating parameters of the power converter system by using multiple bridges operating in parallel, which alters the current distribution and voltage stress characteristics. Each bridge operates at optimized current levels that reduce resistive losses, and the parallel configuration allows for better thermal management and reduced magnetic core losses. This parameter change approach directly improves energy efficiency while maintaining the required power conversion capability.
3Reliability
If conventional power converter systems are used for AC mains power supply, then voltage surge correction can be achieved, but the system requires large magnetic components, increasing cost and size
Solution Approach 1:
The patent segments the surge correction function across multiple parallel bridge circuits, each capable of handling voltage surges independently. When a voltage surge occurs, the control system distributes the correction action across all active bridges, allowing each bridge's magnetic components to be sized for smaller surge handling capacity. The cumulative surge correction capability of all bridges together matches or exceeds that of conventional systems, while individual component sizes are reduced.
Solution Approach 2:
The control system implements beforehand cushioning by continuously monitoring the operating state of all bridge circuits and pre-positioning them to handle potential voltage surges. The controller adjusts the operating points of each bridge in advance to optimize their surge absorption and correction capabilities. This proactive control allows the system to respond to voltage surges more effectively with smaller magnetic components, as the bridges are pre-configured to share the surge stress rather than relying on oversized components for passive protection.
Data Source
AI summary
An AC power converter converts power from an AC power source to an AC load. A DC power holding source is coupled to an input half-bridge switch, a common half-bridge switch and an output half-bridge switch. A controller is coupled to at least two of the input half-bridge switch, the common half-bridge switch, and an output half-bridge switch. The controller switches the input half bridge at the first switching frequency in boost mode and at the line frequency in buck mode. The controller also switches the output half bridge switch at the first switching frequency in buck mode and at the line frequency in boost mode. Input and output low pass filters can eliminate switching frequency energy from entering the AC source and load. The converter maintains a DC power holding source voltage slightly above peak AC input voltage and significantly less than twice the peak AC input voltage.