Bus Selection in Multibus DC Microgrids

Abstract

DC power systems can be made more reliable by using multiple buses for redundancy. Multiple buses provide multiple configuration options for supplying power to the load. Diode OR'ing with auctioneering diodes is perhaps the most common method to connect a load to multiple buses. Although the diode action is automatic and fault-tolerant, it results in ill-defined bus currents when the bus voltages are similar and the potential for uncontrolled switching in a faulted high-impedance system-operating scenarios not often included in a discussion on auctioneering diodes. Active switching and bus converters with auctioneering diodes are control techniques that overcome these limitations by providing full control over the bus selection process. Using local information in the form of the bus voltage, these techniques do not rely on a centralized controller, which improves system reliability. Dwell time is proposed as a technique to stabilize the state-dependent switching in the bus selector.