Showing 7 results for Matrix Converter
A. Dastfan, F. Behrangi,
Volume 5, Issue 1 (3-2009)
Abstract
A conventional high power DC power supply systems consist of a three-phase
diode rectifier followed by a high frequency converter to supply loads at regulated DC
voltage. These rectifiers draw significant harmonic currents from the utility, resulting in
poor input power factor. In this paper, a DC power supply based on dual-bridge matrix
converter (DBMC) with reduced number of switches is proposed. In the proposed circuit,
three switches convert the low frequency AC input to a DC link. A single-phase bridge
inverter converts the DC-link to a high frequency AC output. The output of the matrix
converter is then processed via a high frequency isolation transformer and rectified to the
regulated DC voltage. In the proposed topology only a simple voltage control loop ensures
that the output voltage is regulated against load changes as well as input supply variations
and the current control loop is not used to correct the input currents. Theory analysis and
simulation are made to investigate performance of the proposed circuit. Simulation results
show that in the proposed power supply with 7-switch, the input currents are of a high
quality under varying load conditions and input voltage.
D. Arab Khaburi,
Volume 8, Issue 2 (6-2012)
Abstract
This paper presents a comparative study on the Predictive Direct Torque Control
method and the Indirect Space Vector Modulation Direct Torque Control method for a
Doubly-Fed Induction Machine (DFIM) which its rotor is fed by an Indirect Matrix
Converter (IMC). In Conventional DTC technique, good transient and steady-state
performances are achieved but it presents a non constant switching frequency behavior and
non desirable torque ripples. However, in this paper by using the proposed methods, a fixed
switching frequency is obtained. In this model Doubly-Fed Induction Machine is connected
to the grid by the stator and the rotor is fed by an Indirect Matrix Converter. Functionally
this converter is very similar to the Direct Matrix Converter, but it has separate line and
load bridges. In the inverter stage, the Predictive method and ISVM method are employed.
In the rectifier stage, in order to reduce losses caused by snubber circuits, the rectifier fourstep
commutation method is employed. A comparative study between the Predictive DTC
and ISVM-DTC is performed by simulating these control systems in
MATLAB/SIMULINK software environments and the obtained results are presented and
verified.
R. Ghazi, A. Khajeh,
Volume 9, Issue 3 (9-2013)
Abstract
Nowadays, the doubly-fed induction generators (DFIGs) based wind turbines (WTs) are the dominant type of WTs connected to grid. Traditionally the back-to-back converters are used to control the DFIGs. In this paper, an Indirect Matrix Converter (IMC) is proposed to control the generator. Compared with back-to-back converters, IMCs have numerous advantages such as: higher level of robustness, reliability, reduced size and weight due to the absence of bulky electrolytic capacitor. According to the recent grid codes it is required that wind turbines remain connected to the grid during grid faults and following voltage dips. This feature is called low voltage ride-through (LVRT) capability. In this paper the linear quadratic regulator (LQR) controller is used for optimal control of the DFIG. The weighting matrices of the LQR are obtained using the genetic algorithm (GA) technique. With the LQR controller the intention is to improve the LVRT capability of the DFIG wind turbines to satisfy the new LVRT requirements. Compared to the PI controller, the superiority of the LQR controller in improving the transient stability and LVRT performance of the DFIG wind turbines is evident. Simulation results confirm the efficiency of the proposed controller.
M. Hosseini Abardeh, R. Ghazi,
Volume 11, Issue 1 (3-2015)
Abstract
The matrix converter instability can cause a substantial distortion in the input currents and voltages which leads to the malfunction of the converter. This paper deals with the effects of input filter type, grid inductance, voltage fed to the modulation algorithm and the synchronous rotating digital filter time constant on the stability and performance of the matrix converter. The studies are carried out using eigenvalues of the linearized system and simulations. Two most common schemes for the input filter (LC and RLC) are analyzed. It is shown that by a proper choice of voltage input to the modulation algorithm, structure of the input filter and its parameters, the need for the digital filter for ensuring the stability can be resolved. Moreover, a detailed model of the system considering the switching effects is simulated and the results are used to validate the analytical outcomes. The agreement between simulation and analytical results implies that the system performance is not deteriorated by neglecting the nonlinear switching behavior of the converter. Hence, the eigenvalue analysis of the linearized system can be a proper indicator of the system stability.
M. Alizadeh Moghadam, R. Noroozian, S. Jalilzadeh,
Volume 11, Issue 3 (9-2015)
Abstract
This paper presents modeling, simulation and control of matrix converter (MC) for variable speed wind turbine (VSWT) system including permanent magnet synchronous generator (PMSG). At a given wind velocity, the power available from a wind turbine is a function of its shaft speed. In order to track maximum power, the MC adjusts the PMSG shaft speed.The proposed control system allowing independent control maximum power point tracking (MPPT) of generator side and regulate reactive power of grid side for the operation of the VSWT system. The MPPT is implemented by a new control system. This control system is based on control of zero d-axis current (ZDC). The ZDC control can be realized by transfer the three-phase stator current in the stationary reference frame into d-and q-axis components in the synchronous reference frame. Also this paper is presented, a novel control strategy to regulate the reactive power supplied by a variable speed wind energy conversion system. This control strategy is based on voltage oriented control (VOC). The simulation results based on Simulink/Matlab software show that the controllers can extract maximum power and regulate reactive power under varying wind velocities.
S. Chikha,
Volume 14, Issue 3 (9-2018)
Abstract
In this paper we propose a new configuration of the wind farm connecting with an electrical grid. The proposed Wind Energy Conversion System (WECS) is based on a two stages six-leg matrix converter using to drive a two Doubly Fed Induction Machines operating at different wind speeds. Each Doubly Fed Induction Generator (DFIG) is controlled through the rotor currents using the Finite Set Model Predictive Model (FS-MBC). The proposed control method selects the optimal switching state of the converter that minimizes the cost function where it represents the desired behavior of the system. The optimal voltage vector is then applied to the output of the power converter. The most advantage of the proposed control is its simplicity in implementation, since the method avoids the use of any linear or nonlinear controllers except for the external speed loop and there is no need for any type of modulator such as in PWM or SVM modulation. A cost function is formulated according to desired performance such as regulation of the stator active and reactive powers of the DFIGs and reactive power in the filter side. The control algorithm selects and applies the optimal voltage vector to the DFIG rotor terminals. The supervision algorithm distributes the active and reactive power references in proportional way for each wind turbines. From a safety point, this algorithm provides each wind turbines still operate far from its limits. The performance of a six leg IMC in WECS chain is evaluated in term of a good tracking performance.
E. Bounadja, Z. Boudjema, A. Djahbar,
Volume 15, Issue 3 (9-2019)
Abstract
This paper proposes a novel wind energy conversion system based on a Five-phase Permanent Magnetic Synchronous Generator (5-PMSG) and a Five to three Matrix Converter (5-3MC). The low cost and volume and also eliminating grid side converter controller are attractive aspects of the proposed topology compared to the conventional with back-to-back converters. The control of active and reactive power injected to the grid from the proposed system is carried out by a Direct Power Control (DPC) combined with a Space Vector Modulation (SVM). An advantage of this control, compared with the Conventional Direct Power Control (C-DPC) method, is that it eliminates the lookup table and lowers grid powers and currents harmonics through the use of a standard PI controller instead of hysteresis comparators. The efficiency of proposed whole system has been simulated by using MATLAB/Simulink environment.
