Power Loss Analysis of a Multiport DC – DC Converter for DC Grid Applications

Abstract

In this paper, power losses of a multiport DC -DC converter are analysed. The converter has four bidirectional ports and consists of a triple active bridge and four half bridge converters. As a result, sixteen different operating modes, defined by all combinations of power flow direction, are possible. The converter power losses and resulting efficiencies vary widely with operating conditions. This paper presents methods to accurately calculate the efficiency of the four-port converter in each operating mode using component datasheet information, taking into account losses in the transformer of the triple active bridge converter, passive components and semiconductors. A 200 W converter prototype is used to experimentally validate the loss model for one specific operating mode.

Decentralized Voltage Control for Efficient Power Exchange in Interconnected DC Clusters

“…Advantages of using the FPC include reduced installation space requirements, and reduced cabling costs. The high frequency transformer (HFT) in the FPC also helps to provide different voltage levels and galvanic isolation between the homes [11].…”

“…The FBCs are phase shift,  controlled while the HBCs are duty cycle, d controlled [11]. The PV is operated in MPPT mode by controlling the HBC3 as shown in Fig.…”

“…The FBC1 is taken as a reference FBC and is not controlled. The FBC2 and FBC3 are phase shift controlled and maintains a constant 38 V across C2 and 152 V across C3 respectively [11]. A generic control law of FBC2 and FBC3 is shown in Fig.…”

“…It is minimum (vi=Vmin) when the BESS is fully discharged during overloads. The voltage, vDC on the DC bus can be expressed in terms of vi as follows 11 1…”

“…Furthermore, to reduce cabling costs and for galvanic isolation, each home in the clusters shown in Fig. 1 uses a four port DC-DC converter (FPC) [11] to manage the power flow on the distribution line, the BESS, the appliances, and/or the PV modules. To control the power flow on the distribution line, the FPC adjusts the distribution voltage local to a home based on the power requirements of that home [12].…”