Shipboard MVDC power systems need to support pulsed loads, which have destabilizing ef-fects on the MVDC power transmission bus voltage. Despite the reference shipboard MVDC architecture having energy storage to buffer the large power swings of pulsed loads, a large constant power still needs to be delivered to maintain the energy storage state of charge. This recharging constant power itself introduces small signal instability to the MVDC bus voltage. This thesis investigates the advantages of adding a dynamically tuneable virtual capacitor and resistor in parallel to the pulsed load for maintaining small signal stability. The stabi-lizer is implemented in a negative load configuration in the existing reference architecture hardware, where the stabilizer negatively impacts the power quality of the downstream load. To address this, a dual use is added to existing hardware by having the energy storage also cancel out the newly introduced noise. A controller was designed to control a MVDC power converter module for providing these stability services. In addition, the controller manages its internal energy storage and stabilizes its internal DC bus that powers its downstream pulsed load. / Future ships will have a special shipboard power grid and power converters to power future electronics. Most of these power converters will have an internal battery device that provides power when the generators do not provide enough power. Generators are very slow to change their power output. Some shipboard electronics may consume very large amounts of power at very quickly changing rates, causing instability to the power system. The batteries can accomodate the instability caused by these electronics. However, the batteries need to be quickly recharged, which is also unstable to the special power grid. This thesis modifies the recharging behavior so that it does not cause this instability. Also, it is preferable that the batteries will only draw power from the power grid in one direction and send power to the power consuming electronics. This setup is called negative load. This setup is preferable, because sending power back to the power grid will require extra hardware. Ships can only carry so much equipment due to constraints in weight or room, so additonal hardware is undesireable. There already exists similar research to provide this stabilizing service, but they are not designed for a shipboard power grid supporting these quick high power electronics. This thesis also makes a controls system that manages the battery and other requirements of the power system.
| Identifer | oai:union.ndltd.org:VTETD/oai:vtechworks.lib.vt.edu:10919/94129 |
| Date | 26 September 2019 |
| Creators | Yang, Robin S. |
| Contributors | Computer Engineering, Odendaal, Willem G., Ravindran, Binoy, Brown, Alan J. |
| Publisher | Virginia Tech |
| Source Sets | Virginia Tech Theses and Dissertation |
| Language | en_US |
| Detected Language | English |
| Type | Thesis |
| Format | ETD, application/pdf |
| Rights | In Copyright, http://rightsstatements.org/vocab/InC/1.0/ |
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