Imposed Weighting Factor Optimization Method for Torque Ripple Reduction of IM Fed by Indirect Matrix Converter with Predictive Control Algorithm

Uddin, Muslem,Mekhilef, Saad,Rivera, Marco,Rodriguez, Jose The Korean Institute of Electrical Engineers 2015 Journal of Electrical Engineering & Technology Vol.10 No.1

This paper proposes a weighting factor optimization method in predictive control algorithm for torque ripple reduction in an induction motor fed by an indirect matrix converter (IMC). In this paper, the torque ripple behavior is analyzed to validate the proposed weighting factor optimization method in the predictive control platform and shows the effectiveness of the system. Therefore, an optimization method is adopted here to calculate the optimum weighting factor corresponds to minimum torque ripple and is compared with the results of conventional weighting factor based predictive control algorithm. The predictive control algorithm selects the optimum switching state that minimizes a cost function based on optimized weighting factor to actuate the indirect matrix converter. The conventional and introduced weighting factor optimization method in predictive control algorithm are validated through simulations and experimental validation in DS1104 R&D controller platform and show the potential control, tracking of variables with their respective references and consequently reduces the torque ripple.

Effects of a Static Synchronous Series Compensator (SSSC) Based on a Soft Switching 48-Pulse PWM Inverter on the Power Demand from the Grid

Ustun, Taha Selim,Mekhilef, Saad The Korean Institute of Power Electronics 2010 JOURNAL OF POWER ELECTRONICS Vol.10 No.1

In this paper the effects of a Static Synchronous Series Compensator, which is constructed with a 48-pulse inverter, on the power demand from the grid are studied. Extensive simulation studies were carried out in the MATLAB simulation environment to observe the compensation achieved by the SSSC and its effects on the line voltage, line current, phase angle and real/reactive power. The designed device is simulated in a power system which is comprised of a three phase power source, a transmission line, line inductance and load. The system parameters such as line voltage, line current, reactive power Q and real power P transmissions are observed both when the SSSC is connected to and disconnected from the power system. The motivation for modeling a SSSC from a multi-pulse inverter is to enhance the voltage waveform of the device and this is observed in the total harmonic distortion (THD) analysis performed at the end of the paper. According to the results, the power flow and phase angle can be controlled successfully by the new device through voltage injection. Finally a THD analysis is performed to see the harmonics content. The effect on the quality of the line voltage and current is acceptable according to international standards.

Design and Implementation of a Multi Level Three-Phase Inverter with Less Switches and Low Output Voltage Distortion

Ahmed, Mahrous E.,Mekhilef, Saad The Korean Institute of Power Electronics 2009 JOURNAL OF POWER ELECTRONICS Vol.9 No.4

This paper proposes and describes the design and operational principles of a three-phase three-level nine switch voltage source inverter. The proposed topology consists of three bi-directional switches inserted between the source and the full-bridge power switches of the classical three-phase inverter. As a result, a three-level output voltage waveform and a significant suppression of load harmonics contents are obtained at the inverter output. The harmonics content of the proposed multilevel inverter can be reduced by half compared with two-level inverters. A Fourier analysis of the output waveform is performed and the design is optimized to obtain the minimum total harmonic distortion. The full-bridge power switches of the classical three-phase inverter operate at the line frequency of 50Hz, while the auxiliary circuit switches operate at twice the line frequency. To validate the proposed topology, both simulation and analysis have been performed. In addition, a prototype has been designed, implemented and tested. Selected simulation and experimental results have been provided.

Multistage Inverters Control Using Surface Hysteresis Comparators

Menshawi, Menshawi K.,Mekhilef, Saad The Korean Institute of Power Electronics 2013 JOURNAL OF POWER ELECTRONICS Vol.13 No.1

An alternative technique to control multilevel inverters with vector approximations has been presented. The innovative control method utilizes specially designed two-dimensional hysteresis comparators to simplify the implementation and improve the resultant waveform. The multistage inverter designed with maximum number of levels is operated in such a way to approximate the reference voltage vector by exploiting the large number of multilevel inverter vectors. A three-stage inverter with the main high voltage stage made of three phase, six-switch and singly-fed inverter is considered for application to the proposed design. The proposed control concept is to maintain a higher voltage stage state as long as it can lead to a target vector. High and medium voltage stages controllers are based on surface hysteresis comparators to hold the switching state or to perform the necessary change to achieve its reference voltage with minimal switching losses. The low voltage stage controller is designed to approximate the target reference voltage to the nearest inverter vector using the nearest integer rounding and adjustment comparators. Model simulation and prototype test results show that the proposed control technique clearly outperforms the previous control methods.

Robust Sensorless Sliding Mode Flux Observer for DTC-SVM-based Drive with Inverter Nonlinearity Compensation

Aimad, Ahriche,Madjid, Kidouche,Mekhilef, Saad The Korean Institute of Power Electronics 2014 JOURNAL OF POWER ELECTRONICS Vol.14 No.1

This paper presents a robust and speed-sensorless stator flux estimation for induction motor direct torque control. The proposed observer is based on sliding mode approach. Stator electrical equations are used in the rotor orientation reference frame to eliminate the observer dependence on rotor speed. Lyapunov's concept for systems stability is adopted to confine the observer gain. Furthermore, the sensitivity of the observer to parameter mismatch is recovered with an adaptation technique. The nonlinearities of the pulse width modulation voltage source inverter are estimated and compensated to enhance stability at low speeds. Therefore, a new method based on the model reference adaptive system is proposed. Simulation and experimental results are shown to verify the feasibility and effectiveness of the proposed algorithms.

Multistage Inverters Control Using Surface Hysteresis Comparators

Menshawi K. Menshawi,Saad Mekhilef 전력전자학회 2013 JOURNAL OF POWER ELECTRONICS Vol.13 No.1

An alternative technique to control multilevel inverters with vector approximations has been presented. The innovative control method utilizes specially designed two-dimensional hysteresis comparators to simplify the implementation and improve the resultant waveform. The multistage inverter designed with maximum number of levels is operated in such a way to approximate the reference voltage vector by exploiting the large number of multilevel inverter vectors. A three-stage inverter with the main high voltage stage made of three phase, six-switch and singly-fed inverter is considered for application to the proposed design. The proposed control concept is to maintain a higher voltage stage state as long as it can lead to a target vector. High and medium voltage stages controllers are based on surface hysteresis comparators to hold the switching state or to perform the necessary change to achieve its reference voltage with minimal switching losses. The low voltage stage controller is designed to approximate the target reference voltage to the nearest inverter vector using the nearest integer rounding and adjustment comparators. Model simulation and prototype test results show that the proposed control technique clearly outperforms the previous control methods.

Stability and Performance Investigations of Model Predictive Controlled Active-Front-End (AFE) Rectifiers for Energy Storage Systems

Md. Parvez Akter,Saad Mekhilef,Nadia Mei Lin Tan,Hirofumi Akagi 전력전자학회 2015 JOURNAL OF POWER ELECTRONICS Vol.15 No.1

This paper investigates the stability and performance of model predictive controlled active-front-end (AFE) rectifiers for energy storage systems, which has been increasingly applied in power distribution sectors and in renewable energy sources to ensure an uninterruptable power supply. The model predictive control (MPC) algorithm utilizes the discrete behavior of power converters to determine appropriate switching states by defining a cost function. The stability of the MPC algorithm is analyzed with the discrete z-domain response and the nonlinear simulation model. The results confirms that the control method of the active-front-end (AFE) ectifier is stable, and that is operates with an infinite gain margin and a very fast dynamic response. Moreover, the performance of the MPC controlled AFE rectifier is verified with a 3.0 kW experimental system. This shows that the MPC controlled AFE rectifier operates with a unity power factor, an acceptable THD (4.0 %) level for the input current and a very low DC voltage ripple. Finally, an efficiency comparison is performed between the MPC and the VOC-based PWM controllers for AFE rectifiers. This comparison demonstrates the effectiveness of the MPC controller.

New switched-capacitor-based boost inverter topology with reduced switch count

Siddique, Marif Daula,Mekhilef, Saad,Mohamed Shah, Noraisyah,Mohamed Ali, Jagabar Sathik The Korean Institute of Power Electronics 2020 JOURNAL OF POWER ELECTRONICS Vol.20 No.4

The boosting feature of switched capacitor-based multilevel inverter topologies has been highly recommended for photovoltaic-based applications. However, the main concern with these topologies is the voltage stress across the switches along with the power component count for a higher number of levels. In this paper, a new single-stage boost nine-level boost inverter (9LBI) topology has been proposed with a single floating capacitor unit that pertains to all of the mentioned concern. The proposed topology gives a voltage gain of two, while the voltage stresses across switches have been maintained to be equal to or less than the dc input supply. Phase disposition pulse width modulation (PD-PWM) and nearest level control pulse width modulation (NLC-PWM) techniques have been used for the control of the switches in the proposed topology. A comparative study of different similar topologies in terms of cost, efficiency, voltage stress, and component count sets the standard for the proposed topology. Different simulation and experimental results have been obtained to determine the workability of the proposed topology in different environments and operating conditions.

Design and Implementation of a Multi Level Three-Phase Inverter with Less Switches and Low Output Voltage Distortion

Mahrous E. Ahmed,Saad Mekhilef 전력전자학회 2009 JOURNAL OF POWER ELECTRONICS Vol.9 No.4

This paper proposes and describes the design and operational principles of a three-phase three-level nine switch voltage source inverter. The proposed topology consists of three bi-directional switches inserted between the source and the full-bridge power switches of the classical three-phase inverter. As a result, a three-level output voltage waveform and a significant suppression of load harmonics contents are obtained at the inverter output. The harmonics content of the proposed multilevel inverter can be reduced by half compared with two-level inverters. A Fourier analysis of the output waveform is performed and the design is optimized to obtain the minimum total harmonic distortion. The full-bridge power switches of the classical three-phase inverter operate at the line frequency of 50㎐, while the auxiliary circuit switches operate at twice the line frequency. To validate the proposed topology, both simulation and analysis have been performed. In addition, a prototype has been designed, implemented and tested. Selected simulation and experimental results have been provided.

Compact Wireless IPT System Using a Modified Voltage-fed Multi-resonant Class EF₂ Inverter

Mohammad Kamar Uddin,Saad Mekhilef,Gobbi Ramasamy 전력전자학회 2018 JOURNAL OF POWER ELECTRONICS Vol.18 No.1

Wireless inductive power transfer (IPT) technology is used in many applications today. A compact and high-frequency primary side inverter is one of the most important parts of a WPT system. In this study, a modified class EF-type voltage-fed multi-resonant inverter has been proposed for WPT application at a frequency range of 85–100 kHz. Instead of an infinite input choke inductor, a resonant inductor is used to reduce loss and power density. The peak voltage stress across the MOSFET has been reduced to almost 60% from a class-E inverter using a passive clamping circuit. A simple yet effective design procedure has been presented to calculate the various component values of the proposed inverter. The overall system is simulated using MATLAB/SimPowerSystem to verify the theoretical concepts. A 500-W prototype was built and tested to validate the simulated results. The inverter exhibited 90% efficiency at nearly perfect alignment condition, and efficiency reduced gradually with the misalignment of WPT coils. The proposed inverter maintains zero-voltage switching (ZVS) during considerable load changes and possesses all the inherent advantages of class E-type inverters.