DC Microgrid Capacitor Charging Paths for Faster Bus Tie Startup
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Solution Overview
Problem
In a limited space such as a ship, the direct current microgrid faces challenges in achieving efficient power interchange due to the presence of bus tie capacitors, which can lead to inappropriate bias states and prolonged charging times.
Innovation Solution
A charging system comprising a first fuse connected to the positive electrode wiring of a bus, a second fuse connected to the negative electrode wiring, and a first capacitor capable of cutting at least one of the fuses, along with a charging circuit that charges the second capacitor when specific switching elements are turned off.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If a large capacity bus tie capacitor is used in the direct current microgrid, then the power interchange capacity is improved, but the charging time of the capacitor is prolonged
Solution Approach 1:
The invention divides the charging function into two independent paths: one for the bus tie capacitor (via bus tie switch and bus tie capacitor charging circuit) and another for power converter capacitors (via power converter switches and their respective capacitor charging circuits). This segmentation allows simultaneous charging of different capacitors through dedicated circuits, resolving the time conflict while maintaining the large capacity bus tie capacitor for adequate power interchange capability.
2Power
If a large capacity bus tie capacitor is used in the direct current microgrid, then the power interchange capacity is improved, but the bias state becomes inappropriate causing operational issues
Solution Approach 1:
The invention implements preliminary charging of the bus tie capacitor and power converter capacitors through dedicated charging circuits before the microgrid enters normal operation. The control device activates these charging circuits during startup or when capacitor voltages fall below threshold levels, ensuring capacitors are properly charged in advance to prevent inappropriate bias states and operational failures.
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 proposed solution improves the charging efficiency of capacitors in direct current microgrids with bus tie capacitors, enabling effective power interchange and operation in limited spaces.
Implementation Method 1
a second capacitor that is provided parallel to an input terminal of the bridge circuit and that smooths the direct current power
Implementation Method 2
a charging circuit that is connected between both terminals of the second capacitor of at least one of the plurality of power converters and that charges the second capacitor when the first switching element and the second switching element are turned off
Data Source
AI summary
This charging system is connected between the two terminals of at least one capacitor in the input of a plurality of power converters and charges the capacitor when a first switching element and a second switching element are turned off.