Search Results (3)

This paper proposed a dual DC bus nanogrid with 380 V and 48 V buses and allows the integration of distributed energy resources on two buses. The proposed system employs an interlink converter to enable power sharing between the buses. The integration of distributed energy resources has been found to enhance the reliability of the low-voltage bus in comparison to those that lack such integration. The integration process requires the introduction of a new V-I curve for the interlink converter within a DC nanogrid controlled by DC bus signaling and droop control. Furthermore, selecting a power electronics converter for the interlink converter is essential. This paper employs a dual active bridge with galvanic isolation as an interlink converter and proposes a control strategy for the converter that relies on DC bus signaling and droop control. Moreover, this control methodology serves the purpose of preventing any detrimental impact of the interlink converter on the DC buses through the reprogramming of the V-I curve. Subsequently, the suggested control methodology underwent simulation testing via MATLAB/Simulink, which included two different test categories. Initially, the DAB was evaluated as an interlink converter, followed by a comprehensive assessment of the interlink converter in a complete dual DC bus nanogrid. The results indicate that the DAB has the potential to function as an interlink converter while the suggested control approach effectively manages the power sharing between the two buses. Full article

DC bus-voltage signaling (DBS) and droop control are often used in DC nano and microgrids with decentralized distributed energy resources (DERs). This technique effectively enforces the appropriate contributions of power sources and energy storage systems (ESSs) in steady-state situations. The usage of super capacitors (SCs) in conjunction with batteries in a hybrid energy storage system (HESS) has recently been shown to reduce the influence of high and fast current changes on the losses and lifetime of the battery units. However, regulating the HESS as a single unit eliminates the SC’s potential contribution in improving power quality in a DC nanogrid due to its high-power capabilities. This work discusses employing a dual-droop coefficient to expand DC bus signaling and droop control by introducing a second droop constant in the range of the ESS’s droop constant. The suggested droop constant allows the SC to participate in power-sharing in the steady state. The voltage regulation will improve by decreasing the DC bus voltage variation with the load or power variation in the DC nanogrid. Furthermore, in the droop zone, the battery’s current variation is less, resulting in a smoother transition in the battery current. In addition to this, the contribution that SCs make to the slow component is variable, which is something that might be accomplished by having a changing threshold voltage in the I vs. V curve. Full article

The use of DC distribution networks has several advantages, especially for energy saving and integration of energy storage system and renewable energies. In this regard, DC nano-grids are a very interesting solution when distributing electrical power in households. In this paper, an analysis about the possible bidirectional capability of this DC nano-grid is presented. The end-user can freely connect either a passive load (demanding power) or an active one (able to sink current to the grid). The analysis is divided into three different parts. First, a discussion about the most promising power architecture is addressed, taking into consideration the loads in a house. Second, a standard for voltage regulation in a bidirectional DC nano-grid is proposed. Finally, a possible bus provider for this particular bidirectional DC nano-grid is also addressed. This power converter is based on a Dual Active Bridge cascaded with five synchronous buck converters. The key design aspects of the proposed topology are analyzed to emphasize the particular constraints imposed by the standard and the power architecture. A 500 W, 380 V to 24 V bidirectional bus provider has been built in order to experimentally validate the standard proposal and the design aspects. Full article