Multiport Solid-State Transformer for Isolated DC Ports
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Solution Overview
Problem
Existing power electronic topologies for generating multiple isolated low-voltage DC ports are inefficient due to multiple isolated DC-DC conversion stages, which reduce efficiency and increase costs, and also face challenges with reliability and power density due to high switch counts and bulkier capacitor sizing.
Innovation Solution
A Multiport Solid-State Transformer (MP-SST) system using multi-winding high-frequency transformers with phase angle control, where AC-DC-HFAC modules generate HFAC voltages and HFAC-DC modules produce isolated DC load ports, optimizing power transmission and balancing load demands across multiple isolated DC ports.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple isolated DC-DC conversion stages are used to generate multiple isolated LVDC ports, then isolation between ports is achieved, but system efficiency decreases and device complexity increases
Solution Approach 1:
The patent combines multiple DC-DC conversion functions into a single integrated converter stage that directly generates multiple isolated LVDC ports from MVAC input. This eliminates the need for separate DC-DC conversion stages for each port, reducing energy losses while maintaining port isolation through the transformer architecture.
Solution Approach 2:
The converter system performs multiple functions simultaneously: it provides MVAC to LVDC conversion, generates multiple isolated DC ports, and enables inter-port power transfer all in a single integrated stage. This multi-functional approach reduces the number of isolation stages required while maintaining all necessary isolation capabilities.
2Reliability
If multiple isolated DC-DC conversion stages are used to generate multiple isolated LVDC ports, then port isolation is achieved, but device complexity and cost increase
Solution Approach 1:
The patent merges multiple DC-DC conversion functions into one integrated converter stage with multi-winding transformers. This single stage performs what would otherwise require multiple separate conversion stages, reducing device complexity and component count while maintaining isolation between ports through the transformer's winding structure.
3Power
If MV semiconductor devices are utilized in MVAC-MVDC converter, then power conversion capability is achieved, but reliability and EMI performance deteriorate
Solution Approach 1:
The patent changes the operating voltage parameters by directly converting MVAC to LVDC in a single stage, avoiding the intermediate MVDC level that requires high-voltage semiconductor devices. This parameter change enables the use of lower-voltage, more reliable semiconductor devices while maintaining full power conversion capability.
4Adaptability or versatility
If intermediate MVDC bus is utilized, then power distribution flexibility is improved, but switch count and power electronic stack costs increase
Solution Approach 1:
The patent extracts and eliminates the intermediate MVDC bus from the power conversion architecture. By directly generating multiple isolated LVDC ports from MVAC in a single conversion stage, the system removes the MVDC bus and associated high-voltage switches, reducing device complexity while maintaining the ability to serve multiple DC loads.
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 MP-SST system enhances efficiency and power density by reducing the number of isolation stages, improving reliability, and achieving seamless power balance between load ports, while being scalable and cost-effective.
Implementation Method 1
a plurality of multi-winding high frequency transformers (HFTs) adapted to receive the HFAC voltages from the plurality of AC-DC-HFAC modules
Implementation Method 2
one or more HFAC-DC modules, each of the one or more HFAC-DC modules being coupled to a corresponding secondary winding of the plurality of multi-winding HFTs, thereby generating isolated DC load ports
Data Source
AI summary
A power converter system includes a plurality of AC-DC-HFAC modules configured to generate HFAC voltages from the AC voltage received from a power source. The power converter system further includes a plurality of multi-winding high frequency transformers (HFTs) including primary windings and secondary windings. Each secondary winding of the plurality of multi-winding HFTs coupled to the plurality of AC-DC-HFAC modules generates an HFAC voltage port. Further, the power converter system includes one or more HFAC-DC modules coupled to a corresponding secondary winding of the plurality of multi-winding HFTs, thereby generating isolated DC load ports. The plurality of multi-winding HFTs is operated based on a phase angle control technique for enabling power transmission between the primary windings to each of the secondary windings based on the load demand, thereby providing DC power supply to loads.