Navid R. Zargari

Bio: Navid R. Zargari is an academic researcher from Rockwell Automation. The author has contributed to research in topics: Pulse-width modulation & Capacitor. The author has an hindex of 50, co-authored 255 publications receiving 7729 citations. Previous affiliations of Navid R. Zargari include Ryerson University & Concordia University.

Power conversion and control of wind energy systems

Abstract: Preface. List of Symbols. Acronyms and Abbreviations. 1. Introduction. 1.1 Introduction. 1.2 Overview of Wind Energy Conversion Systems. 1.3 Wind Turbine Technology. 1.4 Wind Energy Conversion System Configurations. 1.5 Grid Code. 1.6 Summary. 2. Fundamentals of Wind Energy Conversion System Control. 2.1 Introduction. 2.2 Wind Turbine Components. 2.3 Wind Turbine Aerodynamics. 2.4 Maximum Power Point Tracking (MPPT) Control. 2.5 Summary. 3. Wind Generators and Modeling. 3.1 Introduction. 3.2 Reference Frame Transformation. 3.3 Induction Generator Models. 3.4 Synchronous Generators. 3.5 Summary. 4. Power Converters in Wind Energy Conversion Systems. 4.1 Introduction. 4.2 AC Voltage Controllers (Soft Starters). 4.3 Interleaved Boost Converters. 4.4 Two-Level Voltage Source Converters. 4.5 Three-Level Neutral Point Clamped Converters. 4.6 PWM Current Source Converters. 4.7 Control of Grid-Connected Inverter. 4.8 Summary. 5. Wind Energy System Configurations. 5.1 Introduction. 5.2 Fixed Speed WECS. 5.3 Variable Speed Induction Generator WECS. 5.4 Variable-speed Synchronous Generator WECS. 5.5 Summary. 6. Fixed-Speed Induction Generator WECS. 6.1 Introduction. 6.2 Configuration of Fixed-Speed Wind Energy Systems. 6.3 Operation Principle. 6.4 Grid Connection with Soft Starter. 6.5 Reactive Power Compensation. 6.6 Summary. 7. Variable-Speed Wind Energy Systems with Squirrel Cage Induction Generators. 7.1 Introduction. 7.2 Direct Field Oriented Control. 7.3 Indirect Field Oriented Control. 7.4 Direct Torque Control. 7.5 Control of Current Source Converter Interfaced WECS. 7.6 Summary. 8. Doubly-Fed Induction Generator Based WECS. 8.1 Introduction. 8.2 Super- and Sub-synchronous Operation of DFIG. 8.3 Unity Power Factor Operation of DFIG. 8.4 Leading and Lagging Power Factor Operation. 8.5 A Steady-State Performance of DFIG WECS. 8.6 DFIG WECS Start-up and Experiments. 8.7 Summary. 9. Variable-Speed Wind Energy Systems with Synchronous Generators. 9.1 Introduction. 9.2 System Configuration. 9.3 Control of Synchronous Generators. 9.4 SG Wind Energy System with Back-to-back VSC. 9.5 DC/DC Boost Converter Interfaced SG Wind Energy Systems. 9.6 Reactive Power Control of SG WECS. 9.7 Current Source Converter Based SG Wind Energy Systems. 9.8 Summary. Appendix A. Per Unit System. Appendix B. Generator Parameters. Appendix C. Problems and Answers Manual.

Evolution of Topologies, Modeling, Control Schemes, and Applications of Modular Multilevel Converters

Abstract: Modular multilevel converter (MMC) is one of the most promising topologies for medium to high-voltage high-power applications. The main features of MMC are modularity, voltage and power scalability, fault tolerant and transformer-less operation, and high-quality output waveforms. Over the past few years, several research studies are conducted to address the technical challenges associated with the operation and control of the MMC. This paper presents the development of MMC circuit topologies and their mathematical models over the years. Also, the evolution and technical challenges of the classical and model predictive control methods are discussed. Finally, the MMC applications and their future trends are presented.

A Novel Three-Phase Three-Leg AC/AC Converter Using Nine IGBTs

Abstract: This paper proposes a novel three-phase nine-switch ac/ac converter topology. This converter features sinusoidal inputs and outputs, unity input power factor, and more importantly, low manufacturing cost due to its reduced number of active switches. The operating principle of the converter is elaborated; its modulation schemes are discussed. Simulated semiconductor loss analysis and comparison with the back-to-back two-level voltage source converter are presented. Finally, experimental results from a 5-kVA prototype system are provided to verify the validity of the proposed topology.

Performance investigation of a current-controlled voltage-regulated PWM rectifier in rotating and stationary frames

Abstract: Active front-end rectifiers with reduced input current harmonics and high input power factor will be required in the near future for utility interfaced applications. In order to meet the new and more stringent regulations with force-commutated switches, the voltage source inverter approach is superior to the conventional current source approach, in terms of number of components and control options. However, the straightforward power angle control of the rectifier is characterized by a slow response and potential stability problems. This paper proposes a current-controlled PWM rectifier as an alternative. It provides near sinusoidal input currents with unity power factor and a low output voltage ripple. Moreover, it produces a well-defined input current harmonic spectrum, exhibits fast transient response to load voltage variations, and is capable of regenerative operation. PWM pattern generation is based on a carrier technique and the current controller is implemented in the: (a) stationary (abc) frame; and (b) rotating (dqo) frame. The design and the performance of the two controller options are investigated and compared. >

A Flying-Capacitor Modular Multilevel Converter for Medium-Voltage Motor Drive

Abstract: This paper presents a flying-capacitor modular multilevel converter (FC-MMC) based on series-connected submodules. It is intended for completely improving the performance of a medium-voltage motor drive system in the entire speed range especially at zero/low speed under rated torque condition. The proposed FC-MMC circuit is characterized by the cross connection of upper and lower arm middle taps through a flying capacitor in per phase leg. By properly controlling the ac current flowing through the flying capacitor, the power balance between upper and lower arms is achieved, leading to very small voltage ripples on submodule dc capacitors in the entire speed range from standstill to rated speed even under the rated torque condition. Meanwhile, no common-mode voltage is injected. Simulation results obtained from a 4160-V 1-MW model show that the proposed FC-MMC along with the proposed control method performances satisfactorily in dynamic and static state even when operated at zero/low speed. Experiments on a downscaled prototype also prove the effectiveness of the proposal.

Recent Advances and Industrial Applications of Multilevel Converters

Abstract: Multilevel converters have been under research and development for more than three decades and have found successful industrial application. However, this is still a technology under development, and many new contributions and new commercial topologies have been reported in the last few years. The aim of this paper is to group and review these recent contributions, in order to establish the current state of the art and trends of the technology, to provide readers with a comprehensive and insightful review of where multilevel converter technology stands and is heading. This paper first presents a brief overview of well-established multilevel converters strongly oriented to their current state in industrial applications to then center the discussion on the new converters that have made their way into the industry. In addition, new promising topologies are discussed. Recent advances made in modulation and control of multilevel converters are also addressed. A great part of this paper is devoted to show nontraditional applications powered by multilevel converters and how multilevel converters are becoming an enabling technology in many industrial sectors. Finally, some future trends and challenges in the further development of this technology are discussed to motivate future contributions that address open problems and explore new possibilities.

Multilevel Voltage-Source-Converter Topologies for Industrial Medium-Voltage Drives

Abstract: This paper presents a technology review of voltage-source-converter topologies for industrial medium-voltage drives. In this highly active area, different converter topologies and circuits have found their application in the market. This paper covers the high-power voltage-source inverter and the most used multilevel-inverter topologies, including the neutral-point-clamped, cascaded H-bridge, and flying-capacitor converters. This paper presents the operating principle of each topology and a review of the most relevant modulation methods, focused mainly on those used by industry. In addition, the latest advances and future trends of the technology are discussed. It is concluded that the topology and modulation-method selection are closely related to each particular application, leaving a space on the market for all the different solutions, depending on their unique features and limitations like power or voltage level, dynamic performance, reliability, costs, and other technical specifications.

A Survey on Cascaded Multilevel Inverters

Abstract: Cascaded multilevel inverters synthesize a medium-voltage output based on a series connection of power cells which use standard low-voltage component configurations. This characteristic allows one to achieve high-quality output voltages and input currents and also outstanding availability due to their intrinsic component redundancy. Due to these features, the cascaded multilevel inverter has been recognized as an important alternative in the medium-voltage inverter market. This paper presents a survey of different topologies, control strategies and modulation techniques used by these inverters. Regenerative and advanced topologies are also discussed. Applications where the mentioned features play a key role are shown. Finally, future developments are addressed.

Current control techniques for three-phase voltage-source PWM converters: a survey

Abstract: The aim of this paper is to present a review of current control techniques for three-phase voltage-source pulsewidth modulated converters. Various techniques, different in concept, have been described in two main groups: linear and nonlinear. The first includes proportional integral (stationary and synchronous) and state feedback controllers, and predictive techniques with constant switching frequency. The second comprises bang-bang (hysteresis, delta modulation) controllers and predictive controllers with on-line optimization. New trends in current control-neural networks and fuzzy-logic-based controllers-are discussed, as well. Selected oscillograms accompany the presentation in order to illustrate properties of the described controller groups.

High-Power Converters and AC Drives

Abstract: Preface. Part One Introduction. 1. Introduction. 1.1 Introduction. 1.2 Technical Requirements and Challenges. 1.3 Converter Configurations. 1.4 MV Industrial Drives. 1.5 Summary. References. Appendix. 2. High-Power Semiconductor Devices. 2.1 Introduction. 2.2 High-Power Switching Devices. 2.3 Operation of Series-Connected Devices. 2.4 Summary. References. Part Two Multipulse Diode and SCR Rectifiers. 3. Multipulse Diode Rectifiers. 3.1 Introduction. 3.2 Six-Pulse Diode Rectifier. 3.3 Series-Type Multipulse Diode Rectifiers. 3.4 Separate-Type Multipulse Diode Rectifiers. 3.5 Summary.(c) References. 4. Multipulse SCR Rectifiers. 4.1 Introduction. 4.2 Six-Pulse SCR Rectifier. 4.3 12-Pulse SCR Rectifier. 4.4 18- and 24-Pulse SCR Rectifiers. 4.5 Summary. References. 5. Phase-Shifting Transformers. 5.1 Introduction. 5.2 Y/Z Phase-Shifting Transformers. 5.3 /Z Transformers. 5.4 Harmonic Current Cancellation. 5.5 Summary. Part Three Multilevel Voltage Source Converters. 6. Two-Level Voltage Source Inverter. 6.1 Introduction. 6.2 Sinusoidal PWM. 6.3 Space Vector Modulation. 6.4 Summary. References. 7. Cascaded H-Bridge Multilevel Inverters. 7.1 Introduction. 7.2 H-Bridge Inverter. 7.3 Multilevel Inverter Topologies. 7.4 Carrier Based PWM Schemes. 7.5 Staircase Modulation. 7.6 Summary. References. 8. Diode-Clamped Multilevel Inverters. 8.1 Introduction. 8.2 Three-Level Inverter. 8.3 Space Vector Modulation. 8.4 Neutral-Point Voltage Control. 8.5 Other Space Vector Modulation Algorithms. 8.6 High-Level Diode-Clamped Inverters. 8.7 Summary. References. Appendix. 9. Other Multilevel Voltage Source Inverters. 9.1 Introduction. 9.2 NPC/H-Bridge Inverter. 9.3 Multilevel Flying-Capacitor Inverters. 9.4 Summary. References. Part Four PWM Current Source Converters. 10. PWM Current Source Inverters. 10.1 Introduction. 10.2 PWM Current Source Inverter. 10.3 Space Vector Modulation. 10.4 Parallel Current Source Inverters. 10.5 Load-Commutated Inverter (LCI). 10.6 Summary. References. Appendix. 11. PWM Current Source Rectifiers. 11.1 Introduction. 11.2 Single-Bridge Current Source Rectifier. 11.3 Dual-Bridge Current Source Rectifier. 11.4 Power Factor Control . 11.5 Active Damping Control. 11.6 Summary. References. Appendix. Part Five High-Power AC Drives. 12. Voltage Source Inverter-Fed Drives. 12.1 Introduction. 12.2 Two-Level VBSI-Based MV Drives. 12.3 Neutral-Point Clamped (NPC) Inverter-Fed Drives. 12.4 Multilevel Cascaded H-Bridge (CHB) Inverter-Fed Drives. 12.5 NPC/H-Bridge Inverter-Fed Drives. 12.6 Summary. References. 13. Current Source Inverter-Fed Drives. 13.1 Introduction. 13.2 CSI Drives with PWM Rectifiers. 13.3 Transformerless CSI Drive for Standard AC Motors. 13.4 CSI Drive with Multipulse SCR Rectifier. 13.5 LCI Drives for Synchronous Motors. 13.6 Summary. References. 14. Advanced Drive Control Schemes. 14.1 Introduction. 14.2 Reference Frame Transformation. 14.3 Induction Motor Dynamic Models. 14.4 Principle of Field-Oriented Control (FOC). 14.5 Direct Field-Oriented Control. 14.6 Indirect Field-Oriented Control. 14.7 FOC for CSI-Fed Drives. 14.8 Direct Torque Control. 14.9 Summary. References. Abbreviations. Appendix Projects for Graduate-Level Courses. P. 1 Introduction. P. 2 Sample Project. P. 3 Answers to Sample Project. Index. About the Author.