In this paper, a classic proportional–integral (PI) control strategy as an energy management strategy (EMS) and a microgrid stand-alone power system configuration are proposed to work independently out of grid. The proposed system combines photovoltaics (PVs), fuel cells (FCs), batteries, and supercapacitors (SCs). The system supplies a dump load with its demand power. The system includes DC/DC and DC/AC converters, as well as a maximum power point tracking (MPPT) to maximize the harvested energy from PV array. The system advantages are represented to overcome the problem of each source when used individually and to optimize the hydrogen consumption. The classic PI control strategy is used to control the main system parameters like FC current and the state-of-charge (SOC) for the battery and SC. In order to analyze and monitor the system, it was implemented in the MATLAB/Simulink. The simulation done for fuzzy logic and high frequency decoupling and state machine control strategies to validate the PI classic control strategy. The obtained results confirmed that the system works efficiently as a microgrid system. The results show that the SOC for the battery is kept between 56 and 65.4%, which is considered a proper value for such types of batteries. The DC bus voltage (VDC) is kept within the acceptable level. Moreover, the H₂ fuel consumption is 12.1 gm, as the FCs are used as supported sources working with the PV. A big area for improvement is available for cost saving, which suggests the need for further research through system optimization and employing different control strategies.

Direct torque control (DTC) is considered as one of the most efficient techniques for speed and/or position tracking control of induction motor drives. However, this control scheme has several drawbacks: the switching frequency may exceed the maximum allowable switching frequency of the inverters, and the ripples in current and torque, especially at low speed tracking, may be too large. In this brief, we propose a new approach that overcomes these problems. The suggested controller is a model predictive controller, which directly controls the inverter switches. It is easy to implement in real time and it outperforms all previous approaches. Simulation results show that the new approach has as good tracking properties as any other scheme, and that it reduces the average inverter switching frequency about 95% as compared to classical DTC.

Droop control is the widespread method for source converters parallel running in DC microgrids, however, this technique has some constraints. The difference in lines resistance is considered one of the main reasons of circulating current, poor of load sharing, and deteriorating voltage regulation. proper load sharing among converters must be ensured by the main control system of DC microgrids, minimum circulating current among sources and minimum voltage deviation. In this work, simple adaptive droop controller is proposed to cover the problems of classical droop control. The introduced algorithm is characterized by low voltage regulation with enhanced load sharing performance of the DC microgrids. The efficiency of the introduced methodology is tested under various operating situations. Simulation consequences show, the proposed technique performance is compared to classical droop control performance.

In this paper, performance of a high gain quasi Y-source impedance network converter is analyzed. This converter has a high voltage gain while using a small duty ratio. Compared to other impedance source converters, Y-source converter operates with lower shoot-through duty cycle for the same boosting gain. To achieve that, a three windings transformer with very low leakage inductance is employed. In turn, the switching losses and heating are low at the same boosting gain. Moreover, in this type of converter, the boosting gain depends on number of variables, and hence more degrees of freedom for meeting design constraints. The voltage and current of the switching elements are analyzed during shoot and non-shoot through. The analysis shows that, for high boosting gain, some components has high voltage stress compared to conventional converters. Moreover, fast switching diodes are required to achieve high boosting gain. The performance of the proposed converter is analyzed using numerical simulation and experimental testing.

Enumerative nonlinear model predictive control for speed tracking problem of linear induction motors has been presented in [1], where the authors show that this control scheme has better performance as compared to direct torque control. In this paper, the authors show that using a load observer for integral action, the performance can be further improved. Specifically simulation results show that a load observer results in better tracking properties and offers more robust control.