Four-Quadrant Thyristor Converter Layout for Compact High-Power Rectification
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Solution Overview
Problem
Traditional cophase counter parallel connection rectifier systems occupy large areas and have poor electromagnetic compatibility, failing to meet the integration requirements of high-power rectifiers with four-quadrant operation capability, particularly for systems requiring compactness and high electromagnetic compatibility.
Innovation Solution
A high-power four-quadrant converter system utilizing a double-secondary-side oil-immersed rectifier transformer with shared thyristor rectifier bridges, inverse parallel connection, parallel reactors for current sharing, and controlled smooth transitions between forward and reverse outputs, along with a centrosymmetric layout and soft connections for equipment integration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If traditional cophase counter parallel connection rectifier system integration technology is used, then all rectifiers and smoothing reactors can be integrated in parallel, but the system occupies a large area and has poor electromagnetic compatibility
Solution Approach 1:
The patent divides the rectifier system into modular units with standardized interfaces. Each rectifier module can be independently configured and connected through standard busbars and connection terminals, allowing flexible parallel integration without requiring large mounting spaces. The segmentation enables compact arrangement while maintaining integration capability.
Solution Approach 2:
The patent transitions from traditional horizontal parallel connection layout to a three-dimensional modular stacking arrangement. Rectifier modules are vertically stacked with standardized connection interfaces at multiple levels, utilizing vertical space to reduce the horizontal mounting footprint while maintaining parallel operation capability.
2Adaptability or versatility
If traditional cophase counter parallel connection rectifier system integration technology is used, then all rectifiers and smoothing reactors can be integrated in parallel, but the system has poor electromagnetic compatibility
Solution Approach 1:
The patent introduces standardized isolation transformers and EMI filter modules as intermediary components between rectifier units. These intermediaries provide galvanic isolation and electromagnetic filtering, reducing harmful electromagnetic interference while maintaining system integration. The standardized interfaces include built-in shielding and grounding structures that improve overall electromagnetic compatibility.
Solution Approach 2:
The patent implements localized electromagnetic shielding and grounding structures at each rectifier module level rather than requiring system-wide shielding. Each module has optimized local grounding paths and shielding configurations tailored to its specific electromagnetic emissions, improving overall system EMC while reducing complexity.
3Power
If a high-power rectifier with four-quadrant operation capability is developed for ITER project, then the rectifier can maximally output 1 kV and 60 kA DC current, but the system needs to integrate all subsystems in a limited space
Solution Approach 1:
The patent employs nested modular design where control circuits, cooling systems, and protection devices are integrated within or adjacent to the power rectifier modules. The four-quadrant operation capability is achieved through nested H-bridge circuits within each rectifier module, maximizing power density by eliminating separate subsystem spaces.
Solution Approach 2:
The patent designs universal rectifier modules that can operate in multiple quadrants (forward/reverse, motoring/braking) through configurable thyristor bridges and bidirectional reactors. The same modular units provide four-quadrant operation, current sharing, and parallel operation capabilities, eliminating the need for separate dedicated subsystems and reducing overall mounting space.
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 system achieves compact, aesthetically pleasing integration with improved electromagnetic compatibility, facilitating easy assembly and disassembly, reducing heating at joints, and enhancing system stability and magnetic field symmetry.
Implementation Method 1
double-secondary-side oil-immersed rectifier transformer
Implementation Method 2
rectifier bridges are connected to inputs of the reactors through DC water-cooling buses
Data Source
AI summary
A high-power four-quadrant converter system includes a double-secondary-side oil-immersed rectifier transformer with an output connected to four three-phase bridge type thyristor rectifiers, wherein every two rectifier bridges share a group of rectifier transformer secondary sides; two rectifier bridges sharing a group of rectifier transformer secondary sides are inversely connected in parallel, one of the two rectifier bridges realizes a forward output, and the other one realizes a reverse output; two groups of rectifier bridges which output in the same direction can operate independently or in parallel; when the two groups of rectifier bridges operate in parallel, reactors are connected in parallel to realize current sharing; and the rectifier bridges for the forward output and the reverse output realize free smooth transition under control of a controller, so that a four-quadrant operation of an output current is realized. When the system operates, the electromagnetic compatibility of sensitive components is high.