Showing 7 results for Gain
J. Fallah Ardashir, M. Sabahi, S. H. Hosseini, E. Babaei, G. B. Gharehpetian,
Volume 13, Issue 2 (6-2017)
Abstract
This paper proposes a new single phase transformerless Photovoltaic (PV) inverter for grid connected systems. It consists of six power switches, two diodes, one capacitor and filter at the output stage. The neutral of the grid is directly connected to the negative terminal of the source. This results in constant common mode voltage and zero leakage current. Model Predictive Controller (MPC) technique is used to modulate the converter to reduce the output current ripple and filter requirements. The main advantages of this inverter are compact size, low cost, flexible grounding configuration. Due to brevity, the operating principle and analysis of the proposed circuit are presented in brief. Simulation and experimental results of 200W prototype are shown at the end to validate the proposed topology and concept. The results obtained clearly verifies the performance of the proposed inverter and its practical application for grid connected PV systems.
T. Azadmousavi, H. Faraji Baghtash, E. Najafi Aghdam,
Volume 14, Issue 2 (6-2018)
Abstract
This work introduces a new and simple method for adjusting the gain of current mirror. The major advantage of the proposed architecture is that, unlike the conventional variable gain current mirror, it does not need the change of the biasing current to adjust current gain. Therefore, the power dissipation remains constant in all of the gain settings. In addition, the proposed variable gain current mirror have linear-in-dB gain control characteristic, simple structure, and small occupied area. The gain of the current mirror can be simply varied from 1.3dB to 21dB while the 3-dB bandwidth of the circuit remains around 12.3MHz or 33.6MHz at operation frequency range of 1.9MHz-14.2MHz and 6.6MHz-40.2MHz respectively. The proposed circuit draws negligible power of 6.9µW from 1.8V supply voltage. The simulation results of designed variable gain current mirror in 0.18μm standard CMOS technology confirms the effectiveness of the proposed circuit.
T. Azadmousavi, H. Faraji Baghtash, E. Najafi Aghdam,
Volume 15, Issue 2 (6-2019)
Abstract
A power efficient gain adjustment technique is described to realize programmable gain current mirror. The dissipation power changes over the wide gain range of structure are almost negligible. This property is in fact very interesting from power management perspective, especially in analog designs. The simple structure and constant frequency bandwidth are other ever-interesting merits of proposed structure. The programming gain range of structure is from zero up to 18dB under operating frequency range from 72 kHz to 173 MHz. The maximum power dissipation of designed circuit is only 3.1 µW which is drawn from 0.7 V supply voltage. Simulation results in 0.18 µm CMOS TSMC standard technology demonstrate the high performance of the proposed structure.
S. H. Montazeri, A. Damaki Aliabad, F. Zare, S. Aghaei,
Volume 17, Issue 1 (3-2021)
Abstract
The direct drive permanent magnet synchronous motor (DD-PMSM) is a suitable choice for high-precision position control applications. Among various control methods of this motor, the vector control approaches especially the field oriented control has a high-performance in the industrial drives. In this method, the components of stator current are controlled independently and as a result, the torque and flux are controlled continuously. Since there are some limitations and constraints in the motor, inverter, and control system, a new anti-windup gain scheduling PID controller based on the adaptive control principles is proposed for the position control loop. In the proposed method, different values are assigned to coefficients of the PID controller according to the position error to achieve high precision. Also, a very high-accuracy encoder and an ARM processor are used for measuring the instantaneous position and implementation of the proposed method, respectively. The simulation and experimental results validate the effectiveness, high accuracy, and good dynamic behavior of the proposed control method.
M. Soruri, S. M. Razavi, M. Forouzanfar,
Volume 18, Issue 3 (9-2022)
Abstract
Power amplifier is one of the main components in the RF transmitters. It must provide various stringent features that can lead to complicating the design. In this paper, a new optimizing method based on the inclined planes system optimization algorithm is presented for the design of a discrete power amplifier. It is evaluated in a 2.4-3 GHz power amplifier, which is designed based on “Cree’s CGH40010F GaN HEMT”. The optimization goals are input and output return losses, Power Added Efficiency, and Gain. Large signal simulation of the optimized power amplifier shows a good performance across the bandwidth. In this frequency range, the input and output return losses are about lower than -10 dB, the Power Added Efficiency is greater than 51%, while the Gain is higher than 13.5 dB. A two-tone test with a frequency space of 1 MHz is applied for the linearity evaluation of the designed power amplifier. The obtained result shows that the power amplifier has good linearity with a low memory effect.
M. Ehsani, A. Oraee, B. Abdi, V. Behnamgol, S. M. Hakimi,
Volume 19, Issue 1 (3-2023)
Abstract
A novel nonlinear controller is proposed to track active and reactive power for a Brushless Doubly-Fed Induction Generator (BDFIG) wind turbine. Due to nonlinear dynamics and the presence of parametric uncertainties and perturbations in this system, sliding mode control is employed. To generate a smooth control signal, dynamic sliding mode method is used. Uncertainties bound is not required in the suggested algorithm, since the adaptive gain in the controller relation is used in this study. Convergence of the sliding variable to zero and adaptive gain to the uncertainty bound are verified using Lyapunov stability theorem. The proposed controller is evaluated in a comprehensive simulation on the BDFIG model. Moreover, output performance of the proposed control algorithm is compared to the conventional and second-order sliding mode and proportional-integral-derivative (PID) controllers.
Saeed Hasanzadeh, Seyed Mohsen Salehi, Mohammad Javad Saadatmandfar,
Volume 20, Issue 3 (9-2024)
Abstract
Various forms of distributed generation (DG), such as photovoltaic (PV) systems, play a crucial role in advancing a more sustainable future, driven by economic factors and environmental policies implemented by governments. DC-DC converters are essential for harnessing power from solar cells, as they maintain a constant output voltage despite fluctuations in input voltage. Typically, step-up converters are employed to raise output voltage levels, though they often apply the same voltage to an active switch as the output voltage, which can be limiting. To effectively integrate distributed generation sources with the utility grid, high-voltage gain step-up converters are necessary since these sources typically operate at low voltage levels. This study presents an enhanced design of non-isolated DC-DC converters with high voltage gain tailored for photovoltaic (PV) applications. The proposed architecture achieves a quadratic increase in output voltage gain, which alleviates voltage stress on the active switch. Our converter design features a quadratic boost converter complemented by a voltage-boosting cell, facilitating significant voltage amplification. This topology benefits from employing an active switch while minimizing the number of inductors required, resulting in a more compact circuit design. Furthermore, the proposed architecture shares characteristics with recently published topologies regarding passive component utilization, voltage gain, and other relevant parameters. To validate our findings, we conducted mathematical analyses and simulations, with results corroborated by experimental data from laboratory prototype tests.
