This paper presents an analysis of a new application of different direct matrix converter topologies used as power interfaces in AC, DC, and hybrid microgrids, with model predictive current control. Such a combination of a converter and control strategy leads to a high power quality microgrid voltage, even with a low power quality main grid voltage and even during the connection and disconnection of a variety of loads and generation sources to the microgrids. These robust systems are suitable for applications in which sensitive loads are to be supplied and these loads are connected close to distributed-generation sources with inherent intermittent behavior. The authors also propose the use of new direct matrix converter configurations with a reduced number of switches in order to achieve reduced cost, reduced failure rate, and higher reliability, which are very desirable in microgrids. Finally, the authors also introduce new hybrid direct matrix converter topologies that provide interesting options for the islanded operation of the microgrids with the use of a battery system. In other words, the proposed hybrid direct matrix converters result in flexible hybrid microgrid configurations integrating DC and AC devices with high power quality and high power supply reliability.

The influence of current and voltage harmonics in the power quality of electrical facilities is currently an important topic in discussion. Considering that in Voltage Source Converter (VSC) applications it is common to utilize resonant controllers to mitigate characteristic current harmonics, this work proposes a methodology to allow the tuning of resonant controllers through a power quality criterion during the design process, enabling the designer to select between harmonic content and stability. The disturbance rejection model that relates the output harmonic currents with the grid voltage harmonics is utilized as basis for the methodology, also providing an analytical calculation of the resonant controller gain according to the imposed harmonic limitations, both for VSCs with regular L as with LCL output filters. Simulations and experiments validate the proposal.

This paper presents the development of a wind energy conversion system co-simulation based on the Functional Mock-up Interface standard aiming at contributing to the development of co-simulation of large electrical power systems by means of open-source and standardized computational tools. Co-simulation enables the computational burden of a monolithic simulation to be shared among several processing units, significantly reducing processing time. Through the Functional Mock-up Interface standard, developed models are encapsulated into Functional Mock-up Unit, providing an extra means for the protection of intellectual property, a very appealing feature for end users, both in industry and academia. To achieve the decoupling of the subsystems, the Bergeron ideal transmission line model will be used, with travel time equal to the simulation time-step. The computational performance and effectiveness of the proposed co-simulation technique was evaluated with a wind power plant with 50 wind turbines. The system digital models were developed into Modelica language, while co-simulation was implemented in Python.

This paper proposes a technical methodology to decarbonize an isolated low-inertia system with the integration of a Renewable Energy Source (RES) and a Battery Energy Storage System (BESS). The proposal focuses on frequency support during contingencies, especially in terms of Synthetic Inertia (SI), for the Wind Power Plant (WPP), and Fast Frequency Response (FFR), for the BESS, allowing for a consistent decarbonization strategy throughout the operation. In particular, the BESS is analytically designed to provide the desired FFR for a contingency situation, allowing the Rate of Change of Frequency (RoCoF) of the system to be mitigated according to a design criterion that only requires the grid inertia and rated parameters, without relying on complex formulations or optimization methods. It is observed that the established design criterion is conservative and the enhancement in RoCoF values is above the expected. Furthermore, the synthetic inertia of the wind power plant can have an individual limited impact on the system’s RoCoF due to design and power ramping time, while the fast frequency response of the BESS has an additional impact due to the lack of power ramping requirements. Real-time simulation results validate the proposed methodology for an offshore industrial application within the Oil & Gas (O&G) industry.