Single-Stage DC-DC Converter Four-Quadrant Operation
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Solution Overview
Problem
Existing series compensating electric power transmission systems are limited to operating in only one direction due to a two-stage configuration of flyback converters and H-Bridge circuits, leading to decreased conversion efficiency and increased size, and can only transmit power when the primary DC voltage is lower than the secondary DC voltage.
Innovation Solution
A single-stage insulated type DC-DC converter is implemented, utilizing a first power conversion unit, a second power conversion unit, and an isolation transformer, with bidirectional switches and unidirectional switching elements connected in series and parallel configurations, allowing operation in all four quadrants regardless of voltage levels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a two-stage configuration of flyback converters and H-Bridge circuits is used, then power transmission is enabled when primary DC voltage is lower than secondary DC voltage, but conversion efficiency decreases and system size increases
Solution Approach 1:
The patent merges the flyback converter and H-Bridge circuit into a single integrated DC-DC converter stage. The converter includes a primary winding connected to the primary DC voltage source, a secondary winding connected to the secondary DC voltage source, and switching elements that enable bidirectional power flow in a unified circuit topology, eliminating the need for separate conversion stages.
Solution Approach 2:
The DC-DC converter is designed with universal functionality to operate in all four quadrants, enabling power transmission regardless of whether the primary DC voltage is higher or lower than the secondary DC voltage. The converter achieves this through bidirectional switches and a configuration that allows energy transfer in both directions without requiring additional circuitry.
2Adaptability or versatility
If a two-stage configuration of flyback converters and H-Bridge circuits is used, then power transmission is enabled when primary DC voltage is lower than secondary DC voltage, but device complexity increases
Solution Approach 1:
The patent combines multiple functional stages into a single DC-DC converter with integrated magnetic components and switching elements. The primary winding, secondary winding, and bidirectional switches are configured in one unified structure that performs both voltage transformation and bidirectional power flow control simultaneously.
Solution Approach 2:
The converter achieves four-quadrant operation capability through a universal circuit topology that handles all operating conditions (power flow directions and voltage relationships) within a single device structure, eliminating the need for multiple specialized stages.
3Adaptability or versatility
If bidirectional switches with unidirectional switching elements connected in series and parallel are used, then bidirectional power transmission in all four quadrants is enabled, but switching control complexity increases
Solution Approach 1:
The converter employs bidirectional switches that can dynamically change their conduction direction based on the operating quadrant. The switching elements are configured to automatically adapt their behavior according to the instantaneous voltage and current directions, enabling seamless transition between all four quadrants of operation.
Solution Approach 2:
The switching control is divided into distinct modes corresponding to each operating quadrant, with each mode utilizing specific switching element combinations. This segmentation allows the control system to manage complexity by handling one quadrant at a time while maintaining overall four-quadrant capability.
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 enables bidirectional power transmission in all four quadrants, improving efficiency and reducing system size by eliminating the need for a two-stage configuration, and allowing power transmission regardless of the voltage levels between the primary and secondary DC sources.
Implementation Method 1
an isolation transformer having a primary winding and a secondary winding, the primary winding being connected to the pair of first alternating current input and output terminals, the secondary winding being connected to the pair of second alternating current input and output terminals
Data Source
AI summary
A series compensating electric power transmission system has an insulated type DC-DC converter that operates in the first through fourth quadrants, first and second DC voltage sources, and first and second power converters. In the converter, a first I/O positive terminal is connected to a first voltage source positive terminal. A first I/O negative terminal is connected to a first voltage source negative terminal. One of second I/O positive and negative terminals is connected to the first voltage source positive terminal. The other of the second I/O positive and negative terminals is connected to a second voltage source positive terminal. The first power converter converts power between the first I/O positive and negative terminals and first AC I/O terminals. The second power converter converts power between the second I/O positive and negative terminals and second AC I/O terminals. The second power converter is configured with a plurality of bidirectional switches.