###### Abstract
However, there is a lack of research in measuring both voltage and current harmonics in EV fast charging. Previous researchers have designed active power filters (APFs) in EV fast charging to decrease the harmonic distortions created by the nonlinear components. AFPs can be classified into two types, namely, shunt active power filter and series active power filter. Shunt APFs are more conventionally used compared to series APFs in the EV fast charging stations. Shunt APFs have several advantages, such as easy installation and capable of improving the power factor by decreasing the reactive power drain on the distribution network [6]. The researchers in [12], developed a fast battery charger with shunt APF to improve the power factor correction and to decrease the THD by imposing the utility to supply the active current. However, the current approaches cannot regulate the charging precisely due to the fact that the interface between the harmonic current and harmonic voltage of the charging station is not considered, and an accurate approach of choosing the safety factor has not been proposed. Recently, multiple control algorithms have been developed in the EV fast charging system in order to reduce the THD in power distribution networks, such as direct power control (DPC) [13], hysteresis control [14; 15], and model predictive control (MPC) [16]. However, one of the main disadvantages of these algorithms is the capability to observe the harmonic distortion limits of specific order harmonic frequencies, (\(10k\pm 1,8k\pm 1\;6k\pm 1,4k\pm 1\); for \(k=1,2,...\)) of the output voltages/currents. In order to address these gaps, this paper proposes a novel technique of designing and developing an EV fast charger with integrated internal model controller (IMC), where the proposed design provides high dynamic operation and low THD of the drawn currents/ voltages. Besides, the developed IMC has superior control performance compared with an existing current control method. In this respect, the developed IMC controller is structurally simple and can be executed by proportional integral (PI) and proportional integral derivative (PID) controllers. The isolation mechanism is provided between the grid and vehicle through a three-phase transformer integrated with the charger system. The proposed controller demonstrates a low THD of the input current with almost unity power factor. Moreover, this EV charger is capable to perform two types of EV charging, where it providesthree-phase AC and DC fast charging, as shown in Figure 1. In this paper, IMC with decoupled controllers are integrated to control three-stage converters of the EV fast charger. The core contributions of this research are as follows:  
1. This work is designed to provide two approaches of fast charging, as it can deliver DC and AC fast charging. 2. The proposed EV fast charger is designed in a significant method that reduces the overall weight and size of the charger. 3. The proposed EV fast charger is more adaptable in different scenarios, specifically where there are restrictions in resources or space. This manuscript is organized as follows. In Section 2, the method of IMC with synchronized decoupled controller is briefly described. Section 3 presents the simulation structure of the proposed EV fast charger by using MATLAB/Simulink 2018a software, and the simulation results are discussed as well. Section 4 describes the prototype setup of the proposed EV fast charger with its experimental results. Outcomes verification and comparison are presented in Section 5. Finally, in Section 6, the conclusion highlights the significant contributions of this research. Figure 1: Overall structure of the proposed electric vehicle (EV) fast charger.