Segmented DC Bus Rectifier Layout for Stable Microgrid Voltage
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Solution Overview
Problem
Existing electrical power supply systems in microgrids, such as those on ships, face challenges in maintaining a constant DC link voltage at varying diesel engine speeds, particularly at partial loads, which affects operational efficiency and reliability.
Innovation Solution
The system employs a segmented DC bus with a diode rectifier and a switchable rectifier, utilizing diode power semiconductors and IGBTs or thyristors, allowing for flexible power distribution and segmentation, enabling efficient operation by isolating segments and selecting feeds based on load demands, and integrating external power sources for optimal energy usage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a single rectifier is used to supply the DC bus, then the system structure is simple, but it cannot maintain constant DC link voltage at varying diesel engine speeds
Solution Approach 1:
The DC bus is divided into multiple segments with independent rectifiers. Each rectifier can be independently controlled to maintain constant DC link voltage at its segment, even when diesel engine speed varies. This segmentation allows the system to preserve voltage stability without requiring a complex unified control system.
Solution Approach 2:
The rectifiers are designed to perform multiple functions: they can operate independently to maintain local voltage stability, work in parallel to share load, and be selectively connected or disconnected based on operational requirements. This multi-functionality resolves the contradiction by providing both simplicity and reliability.
2Ease of operation
If the entire DC bus is de-energized for repairs or maintenance, then safety is ensured, but operational continuity is lost
Solution Approach 1:
The DC bus is segmented into electrically isolated sections with switching devices. This allows maintenance personnel to de-energize and work on one segment while other segments remain operational, maintaining productivity while ensuring safety through electrical isolation.
Solution Approach 2:
Switching devices act as intermediaries between maintenance requirements and operational continuity. These switches can isolate specific segments for maintenance while allowing other segments to continue operating, thus mediating between the need for safe maintenance access and the need to maintain productivity.
3Adaptability or versatility
If a switchable rectifier is used, then flexibility and technical application possibilities increase, but manufacturing cost increases
Solution Approach 1:
The system uses multiple rectifiers of different types (diode and switchable) distributed across segments. This allows the expensive switchable rectifiers to be used only where flexibility is needed, while simpler diode rectifiers handle standard applications, reducing overall manufacturing cost while maintaining necessary adaptability.
Solution Approach 2:
Different rectifier types are deployed based on local requirements within the system. Switchable rectifiers with higher flexibility are placed in segments requiring adaptability, while diode rectifiers are used in segments with stable, predictable loads. This local differentiation optimizes the balance between manufacturing cost and system flexibility.
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
This configuration ensures reliable and efficient power supply, reduces manufacturing and operational costs, and allows for environmentally friendly energy sources to be utilized, enhancing the system's flexibility and adaptability to different operating states and load distributions.
Implementation Method 1
The first rectifier is a diode rectifier and the second rectifier is a switchable rectifier, i.e. comprises switchable power semiconductors. The diode rectifier has diode power semiconductors.
Implementation Method 2
The first rectifier is a diode rectifier and the second rectifier is a switchable rectifier, i.e. comprises switchable power semiconductors. Switchable power semiconductors are IGBTs or thyristors, for example.
Implementation Method 3
at least one diesel (diesel engine) and/or gas turbine is provided which can be used to drive an electrical generator
Data Source
AI summary
An electrical power supply system, in particular for a microgrid, includes a DC bus, and a first rectifier and a second rectifier, with the first and second rectifiers each supplying power to the DC bus. The first rectifier is a diode rectifier and the second rectifier has switchable power semiconductors. The electrical power supply system further includes a generator supplying power to both rectifiers. The rectifiers can be connected at different times according to a load.