Abstract: Nature-inspired metaheuristic algorithms, particularly those founded on swarm intelligence, have attracted much attention over the past decade. Firefly algorithm has appeared in approximately seven years ago, its literature has enlarged considerably with different applications. It is inspired by the behavior of fireflies. The aim of this paper is the application of firefly algorithm for solving a nonlinear algebraic system. This resolution is needed to study the Selective Harmonic Eliminated Pulse Width Modulation strategy (SHEPWM) to eliminate the low order harmonics; results have been applied on multilevel inverters. The final results from simulations indicate the elimination of the low order harmonics as desired. Finally, experimental results are presented to confirm the simulation results and validate the efficaciousness of the proposed approach.
Abstract: Acoustic noise becoming ever more obnoxious radiated by voltage source inverter fed induction motor drive in modern and industrial applications. The drive utilized for industrial and modern applications should use “spread spectrum” innovation known as Random pulse width modulation (PWM) algorithms where acoustic noise emanates through the machine should be critically concerned. This paper illustrates three types of random PWM control algorithms with fixed switching frequency namely 1) Random modulating PWM 2) Random carrier PWM and 3) Random modulating-carrier PWM. The spectrum plots of the motor stator current demonstrate the strength and robustness of the proposed PWM algorithms. To affirm the proposed algorithms, experimental tests have been conducted using dSPACE rt1104 control board on a v/f control three phase induction motor drive fed by DC link cascaded multilevel inverter.
Abstract: This article presents two methods for the
compensation of harmonics generated by a nonlinear load. The first is
the classic method P-Q. The second is the controller by modern
method of artificial intelligence specifically fuzzy logic. Both
methods are applied to a shunt Active Power Filter (sAPF) based on a
three-phase voltage converter at five levels NPC topology. In
calculating the harmonic currents of reference, we use the algorithm
P-Q and pulse generation, we use the intersective PWM. For
flexibility and dynamics, we use fuzzy logic. The results give us clear
that the rate of Harmonic Distortion issued by fuzzy logic is better
than P-Q.
Abstract: A Space Vector based Pulse Width Modulation
control technique for the three-phase PWM converter is proposed in
this paper. The proposed control scheme is based on a synchronous
reference frame model. High performance and efficiency is obtained
with regards to the DC bus voltage and the power factor
considerations of the PWM rectifier thus leading to low losses.
MATLAB/SIMULINK are used as a platform for the simulations and
a SIMULINK model is presented in the paper. The results show that
the proposed model demonstrates better performance and properties
compared to the traditional SPWM method and the method improves
the dynamic performance of the closed loop drastically.
For the Space Vector based Pulse Width Modulation, Sine signal
is the reference waveform and triangle waveform is the carrier
waveform. When the value sine signal is large than triangle signal,
the pulse will start produce to high. And then when the triangular
signals higher than sine signal, the pulse will come to low. SPWM
output will changed by changing the value of the modulation index
and frequency used in this system to produce more pulse width. The
more pulse width produced, the output voltage will have lower
harmonics contents and the resolution increase.
Abstract: Application of neural networks in execution of
programmed pulse width modulation (PPWM) of a voltage source
inverter (VSI) is studied in this paper. Using the proposed method it is
possible to cancel out the desired harmonics in output of VSI in
addition to control the magnitude of fundamental harmonic,
contineously. By checking the non-trained values and a performance
index, the most appropriate neural network is proposed. It is shown
that neural networks may solve the custom difficulties of practical
utilization of PPWM such as large size of memory, complex digital
circuits and controlling the magnitude of output voltage in a discrete
manner.
Abstract: In this paper, we investigated vector control of an induction machine taking into account discretization problems of the command. In the purpose to show how to include in a discrete model of this current control and with rotor time constant update. The results of simulation obtained are very satisfaisant. That was possible thanks to the good choice of the values of the parameters of the regulators used which shows, the founded good of the method used, for the choice of the parameters of the discrete regulators. The simulation results are presented at the end of this paper.
Abstract: Direct Torque Control is a control technique in AC
drive systems to obtain high performance torque control. The
conventional DTC drive contains a pair of hysteresis comparators.
DTC drives utilizing hysteresis comparators suffer from high torque
ripple and variable switching frequency. The most common solution
to those problems is to use the space vector depends on the reference
torque and flux. In this Paper The space vector modulation technique
(SVPWM) is applied to 2 level inverter control in the proposed
DTC-based induction motor drive system, thereby dramatically
reducing the torque ripple. Then the controller based on space vector
modulation is designed to be applied in the control of Induction
Motor (IM) with a three-level Inverter. This type of Inverter has
several advantages over the standard two-level VSI, such as a greater
number of levels in the output voltage waveforms, Lower dV/dt, less
harmonic distortion in voltage and current waveforms and lower
switching frequencies. This paper proposes a general SVPWM
algorithm for three-level based on standard two-level SVPWM. The
proposed scheme is described clearly and simulation results are
reported to demonstrate its effectiveness. The entire control scheme is
implemented with Matlab/Simulink.
Abstract: Multi-level voltage source inverters offer several
advantages such as; derivation of a refined output voltage with
reduced total harmonic distortion (THD), reduction of voltage ratings
of the power semiconductor switching devices and also the reduced
electro-magnetic-interference problems etc. In this paper, new
carrier-overlapped phase-disposition or sub-harmonic sinusoidal
pulse width modulation (CO-PD-SPWM) and also the carrieroverlapped
phase-disposition space vector modulation (CO-PDSVPWM)
schemes for a six-level diode-clamped inverter topology
are proposed. The principle of the proposed PWM schemes is similar
to the conventional PD-PWM with a little deviation from it in the
sense that the triangular carriers are all overlapped. The overlapping
of the triangular carriers on one hand results in an increased number
of switchings, on the other hand this facilitates an improved spectral
performance of the output voltage. It is demonstrated through
simulation studies that the six-level diode-clamped inverter with the
use of CO-PD-SPWM and CO-PD-SVPWM proposed in this paper is
capable of generating multiple levels in its output voltage. The
advantages of the proposed PWM schemes can be derived to benefit,
especially at lower modulation indices of the inverter and hence this
aspect of the proposed PWM schemes can be well exploited in high
power applications requiring low speeds of operation of the drive.
Abstract: Induction motors are being used in greater numbers
throughout a wide variety of industrial and commercial applications
because it provides many benefits and reliable device to convert the
electrical energy into mechanical motion. In some application it-s
desired to control the speed of the induction motor. Because of the
physics of the induction motor the preferred method of controlling its
speed is to vary the frequency of the AC voltage driving the motor. In
recent years, with the microcontroller incorporated into an appliance
it becomes possible to use it to generate the variable frequency AC
voltage to control the speed of the induction motor.
This study investigates the microcontroller based variable
frequency power inverter. the microcontroller is provide the variable
frequency pulse width modulation (PWM) signal that control the
applied voltage on the gate drive, which is provides the required
PWM frequency with less harmonics at the output of the power
inverter.
The fully controlled bridge voltage source inverter has been
implemented with semiconductors power devices isolated gate
bipolar transistor (IGBT), and the PWM technique has been
employed in this inverter to supply the motor with AC voltage.
The proposed drive system for three & single phase power inverter
is simulated using Matlab/Simulink. The Matlab Simulation Results
for the proposed system were achieved with different SPWM. From
the result a stable variable frequency inverter over wide range has
been obtained and a good agreement has been found between the
simulation and hardware of a microcontroller based single phase
inverter.
Abstract: This paper presents a comparative study on two most
popular control strategies for Permanent Magnet Synchronous Motor
(PMSM) drives: field-oriented control (FOC) and direct torque
control (DTC). The comparison is based on various criteria including
basic control characteristics, dynamic performance, and
implementation complexity. The study is done by simulation using
the Simulink Power System Blockset that allows a complete
representation of the power section (inverter and PMSM) and the
control system. The simulation and evaluation of both control
strategies are performed using actual parameters of Permanent
Magnet Synchronous Motor fed by an IGBT PWM inverter.
Abstract: Most high-performance ac drives utilize a current
controller. The controller switches a voltage source inverter (VSI)
such that the motor current follows a set of reference current
waveforms. Fixed-band hysteresis (FBH) current control has been
widely used for the PWM inverter. We want to apply the same
controller for the PWM AC chopper. The aims of the controller is to
optimize the harmonic content at both input and output sides, while
maintaining acceptable losses in the ac chopper and to control in
wide range the fundamental output voltage. Fixed band controller has
been simulated and analyzed for a single-phase AC chopper and are
easily extended to three-phase systems. Simulation confirmed the
advantages and the excellent performance of the modulation method
applied for the AC chopper.
Abstract: This paper proposes a synchronized random switching frequency pulse width modulation (SRSFPWM). In this technique, the clock signal is used to control the random noise frequency which is produced by the feedback voltage of a hysteresis circuit. These make the triangular carrier frequency equaling to the random noise frequency in each switching period with the symmetrical positive and negative slopes of triangular carrier. Therefore, there is no error voltage in PWM signal. The PSpice simulated results shown the proposed technique improved the performance in case of low frequency harmonics of PWM signal comparing with conventional random switching frequency PWM.