Series-Connected DC Distribution With Solid-State Transformers
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Solution Overview
Problem
Existing power distribution systems face inefficiencies and complexity in managing AC and DC power distribution, particularly in handling varying current requirements across multiple load legs, which can lead to inefficiencies and the need for additional circuitry like PFC and harmonic filters.
Innovation Solution
A DC-power distribution system utilizing series-connected load legs with solid-state transformers, where each leg is rated for a fraction of the total voltage, and secondary converters enable independent current control and sharing, allowing for flexible and efficient power management.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If AC power distribution is used with multiple load legs, then power can be delivered to multiple devices, but additional circuitry like PFC and harmonic filters is required, increasing device complexity
Solution Approach 1:
The system divides the power distribution into separate DC bus segments (first DC bus and second DC bus) that can be independently managed. Each segment serves specific load legs, allowing independent control and reducing the need for complex filtering circuitry across the entire system. The segmentation enables modular expansion without proportionally increasing complexity.
Solution Approach 2:
The patent replaces traditional AC power distribution mechanics with a DC power distribution system. By converting AC to DC at the source and distributing DC power through solid-state transformers and DC-DC converters, the system eliminates the need for PFC circuits and harmonic filters that are mandatory in AC systems, thereby reducing device complexity while maintaining power delivery capability.
2Device complexity
If series-connected load legs are used, then voltage control is simplified and circuitry needs are reduced, but independent current control across legs becomes challenging
Solution Approach 1:
The patent introduces secondary converters as intermediary devices between the series-connected load legs and the DC buses. These converters act as mediators that enable independent current control for each load leg while maintaining the series connection topology. The secondary converters translate the simplified voltage control at the primary level into flexible current control at the load level.
Solution Approach 2:
The system dynamically changes operating parameters by controlling the duty cycles and switching frequencies of the solid-state transformers and secondary converters. This allows independent adjustment of current levels for each load leg connected in series, providing operational flexibility without requiring complex circuitry modifications to the series topology.
3Productivity
If solid state transformers are used, then power distribution efficiency is improved and circuitry is reduced, but the system requires DC power sources and conversion infrastructure
Solution Approach 1:
The patent merges the AC-to-DC conversion function with the power distribution function by integrating solid-state transformers that perform both voltage transformation and rectification. The solid-state transformers combine multiple functions (rectification, isolation, voltage regulation) into single devices, reducing the need for separate conversion infrastructure while maintaining high efficiency.
Solution Approach 2:
The solid-state transformers in the system are designed with multi-functionality, serving as both AC-to-DC converters and voltage regulators simultaneously. They can operate in different modes (buck, boost, or isolated) depending on the application requirements, reducing the need for specialized conversion equipment and simplifying the overall infrastructure.
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 efficient power distribution with reduced circuitry needs, simplified voltage control, and the ability to handle varying current demands across multiple load legs, enhancing scalability and redundancy.
Implementation Method 1
solid state transformer
Data Source
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AI summary
Examples of the disclosure include a power system comprising a plurality of converters configured to receive DC power, the plurality of converters including a plurality of primary windings and a plurality of secondary windings, wherein each primary winding of the plurality of primary windings is coupled in series, and each secondary winding of the plurality of secondary windings is configured to be coupled to at least one load.