جستجوی مقالات مرتبط با کلیدواژه « Perturb » در نشریات گروه « مواد و متالورژی »

In this research, a single-phase multilevel inverter with a reduced number of switches and driver circuits is introduced for analysis in photovoltaic systems. The proposed multilevel inverter consists of two parts, basic circuit, and H-bridge, which are responsible for generating voltage levels and symmetry of voltage levels (positive and negative), respectively. The proposed basic circuit in this paper consists of six unidirectional switches and three input sources and doesn’t use any capacitors or diodes, which reduces the volume and complexity of the control system. In this paper, the seven-level proposed structure is simulated in the MATLAB/Simulink software and the utilized modulation to generate the output voltage levels is level shifted pulse width modulation. Moreover, photovoltaic systems are exploited to supply the proposed inverter’s input sources, which work with perturb and observe algorithm at the maximum power point. In the simulation section, the voltage, current, power waveforms of the photovoltaic system, and the voltage of the proposed inverter input sources are demonstrated, and the voltage and current waveforms of the inverter for different conditions such as radiation and modulation index change are given. Finally, to show the merits and features of the proposed topology, the inverter is compared with some recent symmetrical structures in terms of the number of components and the rated voltage of the switches.

Maximum Power Point (MPP) tracker has an important role in the performance of fuel cell (FC) systems improvement. Tow parameters which have effect on the Fuel cell output power are temperature and membrane water. So contents make the MPP change by with variations in each parameter. In this paper, a new maximum power point tracking (MPPT) method for Proton Exchange Membrane (PEM) fuel cell is proposed. This method is based on water cycle algorithm (WCA). In order to show the performance and the accuracy of the proposed method, a system consisting of one Proton Exchange Membrane (PEM) fuel cell, one boost converter, one WCA based MPP tracker and one load is considered. WCA determines voltage corresponding to the maximum power of FC then one PID controller tunes the duty cycle of the boost converter. The performance of the proposed method is compared with three other MPPT methods (Perturb and Observe, Voltage-based MPPT and current-based MPPT). The results show that the proposed MPPT method has a high accuracy and a fast response, they also indicate that the proposed method has the better performance in comparison with the other studied methods.