## 4 PV Systems--Implementation and Remote-Control Methods
### Remote-Control Methods for PV Systems  
Modern solar systems use modern devices in their implementation and operation which have intelligent functions, such as artificial intelligence algorithms and remote control. Usually, the control system is integrated with a monitoring system, as in [26]. Based on the data collected in real-time by the monitoring system, the control system can quickly detect faults, especially anomalies occurring in the DC and AC outputs [22]. One of the smarter components is the inverter, which can manage the voltage and current during the PV system's operation and can be connected to the Internet by offering remote-control functions, as in Figure 7. For on-grid cases, the voltage, amplitude, and invertor's frequencies are synchronized with each other when the PV system is connected to the grid [36]. Control from a distance can be applied to other components, such as the battery packs, if they have a smart BMS connected, and the charge controller; also, these devices offer functions to modify the PV system's parameters during the solar system's operation: the modification can be done manually by people, or dynamically using AI algorithms which take decisions in real-time based on the data collected in real-time from the PV system [35]. This can be done by using transmission protocols such as the Bluetooth, Wi-Fi, ZigBee, and GSM protocols [9]. The PV panels and systems are integrated successfully in IoT applications, from where other IoT components can have a specific behavior or make a decision based on the data collected from the PV panels [24]. The control system requires intervention only in the case of error or anormal behavior, such in [37], where the control function is activated when the temperature value is greater than 40 \({}^{\circ}\)C, then the system is cooled; the control function is also activated when the water's temperature is greater than 70 \({}^{\circ}\)C, and in this case the hot water is exchanged with cold water. In Table 1 are presented different types of PV systems with control from distance. \begin{table}
\begin{tabular}{c c c c} \hline
**Ref.** & **Communication** & **Description** & **Comments** \\ \hline \multirow{3}{*}{[38]} & \multirow{3}{*}{Wi-Fi} & The proposed solution is based on open-access software and & \\  & & cloud services, and the data acquisition function collects & The system’s remote control is \\  & & data in real-time. The control of system consists in On–Off & limited to On/Off actions. \\ \hline \multirow{6}{*}{[39]} & \multirow{3}{*}{Satellite} & A remote performance check including an automated & \\  & & failure-detection routine for PV systems has been developed & \\  & & within the PVSAT-2 project. The solution detects and & \\ \cline{1-1}  & & control remotely the failure of devices such as the inverter, & \\ \cline{1-1}  & & but also failures regarding degradation, module defects, & \\ \cline{1-1}  & & grid outages, power limitations, hot inverter, high & \\ \cline{1-1}  & & temperature, and maximum power point tracking. & \\ \hline \end{tabular}
\end{table} 
Table 1: PV system—remote-control implementations. Figure 7: The logical scheme of remote control for an inverter. The automation in solar systems is obtained by the integration of intelligent controllers through the replication of biological intelligence. The intelligent controllers do not require the systems' mathematical modeling and have the ability to approximate non-linearities. There are considered to be three types of intelligent controllers: repetitive controllers (improves the system output waveform), neural network controllers (based on the human nervous system and a connection of many artificial neurons), and fuzzy logic controllers (used to control the system dynamics) [16]. Energy production depends on the environmental irradiance and temperature parameters, which causes PV panels to have nonlinear characteristics. In uniform conditions, there is only one maximum point, called the maximum power point (MPP), which causes a PV system to operate at maximum efficiency.