# LoRa Enabled Smart Inverters for Microgrid Scenarios with Widespread Elements
## 1 Introduction  
The concept of localizing energy production, in order to minimize the additional and unnecessary transmission and distribution costs and complexities, has gained a lot of attention recently. Distributed generation, based on renewable energies, is the cornerstone of microgrid (MG) technology. In general, a microgrid is a small-scale grid consisting of distributed generators and loads, which are electrically connected and hierarchically controlled. An MG must be able to operate in isolation and, in some cases, in interaction with other grids [1]. The idea of decentralization in MG ideology is not limited to the power lines, but also includes the information exchange networks. Arguably, one of the top priorities of MG research is to limit communication as much as possible. This work proposes a long-range and low-power communication system for smart inverters to be used for MG control and management applications [2]. It should be noted that the type of communication system selected for any application depends on the unique requirements and restrictions of the specific scenario. For instance, the proximity of the communication nodes is one of the factors. The latency tolerance of the application is another consideration. Communication technologies based on the internet of things (IoT) can be effectively used for the application of this study according to their low power and ease of implementation characteristics [3]. There are various types of this machine-to-machine (M2M) communication technology that offer different characteristics [4]. However, as a rough classification, they can be either short-range or long-range [2]. Short-range physical layer protocols, such as IEEE 802.11 (WiFi) or IEEE 802.15.4 (ZigBee-Physicaland data link layers), are mostly used for indoor applications such as home automation systems. Long-range technologies are of two main categories. First, the technologies that operate inside the territory of licensed cellular frequencies, such as narrow-band internet of things protocol (NB-IoT) [5]. NB-IoT and other similar cellular-based technologies have their design-oriented advantages, such as very high quality of service and low latency measurements. However, in the case of rural areas, accessibility can be an issue with cellular networks. Furthermore, the implementation and operational costs of such systems are not always justifiable for all applications, especially when there is a high number of nodes. The other type is low-power wide-area networks (LPWAN). The common characteristics of various technologies that belong to this group are long-range, small energy consumption, cheap, and easy to implement devices that transmit on unlicensed frequency bands [6]. LoRa, which stands for long-range, is a proprietary physical layer technology that can be used to create an LPWAN structure. Apart from its long-range capability, other features such as ease of implementation, security, open access, and the possibility of creating private networks nominate it as one of the best in this category [7; 8]. As a result, in this study, the proposed communication framework is based on LoRa modulation. The main contributions of this paper are explained as follows:  
* Providing justification remarks on the superiority of LoRaWAN in comparison with other LPWAN technologies for being used in MG applications. * A detailed tutorial on chirp spread spectrum (CSS) and LoRa modulation, accompanied by related equations and visual spectral analysis of LoRa frames. * The concept of utilizing LPWAN technologies and specifically LoRaWAN for remote MG management has been introduced and conceptualized. * An experimental testbed is provided to validate the implementation of LoRaWAN communication protocol in the control structure of power converters. Details of the communication and power system are explained so that other researchers can easily replicate the experiments. * It is demonstrated that grid-feeding inverters can follow externally provided power setpoints.