**1. Introduction**

Romania, as a signatory country of the Paris Agreement [1], has committed to reducing greenhouse gas emissions by 43% by 2030 compared to 2005 and to participate in the European Union's efforts to reduce greenhouse gas emissions by 30% by 2030.

In Reference [2], the authors depicted that the charging time is one of the main challenges that the electrical vehicle (EV) industry is facing. Generally, the EV charging levels are classified according to their power charging rates [3]. Overnight charging takes place in level I, as the EVs are plugged to a convenient power outlet (120 V) for slow charging (1.5–2.5 kW) over long hours. The main concern of level-I is the long charging time, which renders this charging level unsuitable for long driving cycles when more than one charging operation is needed. Moreover, from the electrical grid operation point of view, the long charging hours at night overloads the distribution transformers as they are not allowed to rest in a grid system with a high number of connected EVs [4]. Level-II charging requires a 240 V outlet; thus, it is characteristically used as the prime charging means for public and private facilities. This charging level is capable of supplying power in the range of 4–6.6 kW over a period of 3–6 h in order to restock the depleted EV batteries. The time required is still the main drawback in this charging level. Additionally, voltage sags and high-power losses in an electrical grid system with a high penetration of level II charging are some of the facing challenges for its widespread. Control and coordination in level II would reduce the negative impacts of level-II charging [5]; however, this requires an extensive communication system to be adopted. In general, both levels I and II require single-phase power sources with onboard vehicle chargers. On the contrary, three-phase power systems are used with off-board chargers for level III fast charging rates (50–75 kW). The use of fast charging stations significantly reduces the EV charging time for a complete charging cycle. Additionally, widespread deployment of fast EV charging stations across the urban and the residential areas would eliminate the EV range anxiety concern [6,7]. However, the high-power charging rates are essential over a short interval of time for level-III charging which imposes a very high demand on the utility grid [8,9]. The current grid infrastructure is not capable of supporting the desired high charging rates of level-III. Thus, accomplishing fast charging rates while solely depending on the electrical grid does require not only the improvement of the charging system but also the improvement of the electrical grid capacity. Additionally, drawing large amounts of current from the electrical grid will increase the utility charges, especially at the peak hours and, consequently, will increase the system cost. The impact of an EV charging station load on the electric grid systems is thoroughly discussed in Reference [10].

Romania, according to European Commission (EC) Directives 2016/30 November 2016 [11–13], has as strategic objective the clean energy [14,15]. Recently, the interest in producing electrical energy by using renewable sources is growing up. As conventional power generation sources, the wind energy is now a real competitive alternative [16]. If the renewable energy is used for charging electrical vehicles (EVs), then we can consider these vehicles with zero emissions [17]. In this context, as the number of electrical vehicles (EVs) will increase, it will also be necessary to increase the number of the charging stations which will have a negative impact on the power quality of the power network (Overvoltage, Voltage Sag) [18–22]. But, with the increase in the number of charging stations installed, the problem will be to carry out their maintenance. In this paper, a proposed EV simulator and a complete solution for charging stations (also called EVSE—electric vehicle supply equipment), that can be located in the office or mall parking area, are presented. The EV simulator can be a useful tool for those who do maintenance at the charging stations, as it can simulate all the cases in which an EV can be found, thus verifying the good functioning of the EVSE. The solution proposed in this paper can be implemented in the office or mall parking area, where the customers have the benefit of being able to charge their EVs for free. It is necessary to implement an efficient solution by which the customers are offered the certainty that their EV will not be disconnected from the charging station by an unauthorized person.

The originality of this paper is based on the specialized literature according to State of The Art, the originality of the research presented in the article consists in the development of an EV simulator for charging stations in mode 3, which helps the companies dedicated to the maintenance of the charging stations [22–24]. The innovation is given by the fact that the programmable logic controller (PLC) and human-machine interface (HMI) charging station control solution allows users to load EVs without the need for an radio-frequency identification (RFID) card, using a unique user-selected code that provides security during charging.

The unidirectional communication is achieved using the PWM (Pulse Width Modulation) signal with 1 KHz values [25,26]. The duty cycle of the PWM signal is closely related to the consumption of predefined current, which should not be exceeded. By modelling the PWM signal, the maximum current consumed by the EV can become restricted [17–19]. Knowing the number of phases used, the maximum permissible power can be calculated. Thus, using the PWM signal the load power can be controlled.

In the European Union and other countries that accept the standard International Electrotechnical Commission (IEC) 61851-1, it is used for charging stations. The standard is intended for defining general requirements for charging stations [20–22], used together with other standards (Ex. IEC 61851-22). The purpose of IEC 61851-1 is to cover EV charging equipment by providing AC power. This standard defines the input voltage limit at 1000 V.

This research tries to present a series of optimal solutions regarding the use and maintenance of charging stations. The present research represents an intermediate phase that is part of a complex research project [13]. The main objectives are the implementation of advanced theoretical and technological solutions to ensure some charging stations, fixed and mobile, for electric vehicles (EV) and hybrid electric vehicles plug-in (PHEV). In this context, this work represents a starting point for the development of fixed charging station in mode 3, according IEC 61851-1 Standard [24–26].
