Mehdi Abolhassani

Integrated Doubly Fed Electric Alternator/Active Filter (IDEA), a Viable Power Quality Solution, for Wind Energy Conversion Systems

In response to electric energy crisis and power quality concerns, a simple and low-cost variable speed integrated doubly fed electric alternator/active filter (IDEA) for wind energy conversion systems is proposed. The proposed IDEA is capable of simultaneously capturing maximum power of wind energy with fluctuating wind speed and improving power quality, which are achieved by canceling the most significant and troublesome harmonics of the utility grid. Power factor correction and reactive power control are the other two significant features of the proposed technology. The back-to-back current-regulated power converters are employed to excite the rotor of IDEA. The control strategy of rotor side power converter is based on position sensorless field oriented control method with higher power density. A laboratory prototype has been fabricated and tested, and a TMS3202407 DSP-based controller has been used to control the back-to-back power converters. Analysis and experimental results are presented to demonstrate the effectiveness of the proposed integrated IDEA.

A novel multiphase fault tolerant high torque density permanent magnet motor drive for traction application

This paper presents a novel five-phase fault tolerant permanent magnet motor drive with higher performance and reliability for use in safety-critical applications. A new machine design is developed for fault tolerant operation without severely comprising the drive performance. Fault tolerance is achieved by employing a new fractional-slot concentrated windings configuration PM motor drive, with each phase electrically, magnetically, thermally and physically independent of all others. The proposed motor drive system poses with higher torque density, negligible cogging torque, and less than plusmn0.5% torque ripple. Power converter requirement are discussed and control strategies to minimize the impact of a machine or converter fault are developed. Beside, all the requirement of a fault tolerant operation, including high phase inductance and negligible mutual coupling between phases are met. Analytical and finite element analysis and comparison case studies are presented

A sensorless integrated doubly-fed electric alternator/active filter (IDEA) for variable speed wind energy system

In response to energy concerns and power quality issues, a viable, simple and low cost sensorless integrated doubly-fed electric alternator/active filter (IDEA) for variable wind energy conversion system (WECS) is proposed. The proposed IDEA is capable of simultaneous generation of optimized green power and improving power quality, which are achieved by canceling the most significant and troublesome harmonics of the utility lines. Power factor correction and reactive power control are the other two significant features of the proposed technology. A sensorless field oriented method to control the IDEA with higher power density is also part of this development. Analysis and simulation as well as experimental results are presented to demonstrate the effectiveness of the proposed IDEA. The overall algorithm has been implemented using the TI DSP controller, TMS320LF2407.

Fault tolerant permanent magnet motor drives for electric vehicles

This paper presents a novel five-phase fault tolerant interior permanent magnet (IPM) motor drive with higher performance and reliability for electric vehicles applications. A new machine design along with efficient control strategy is developed for fault tolerant operation of electric drive without severely compromising the drive performance. Fault tolerance is achieved by employing a five phase fractional-slot concentrated windings configuration IPM motor drive, with each phase electrically, magnetically, thermally and physically independent of all the others. The proposed electric drive system presents higher torque density, negligible cogging torque, and about ±0.5% torque ripple. Power converter requirements are discussed and control strategies to minimize the impact of machine or converter fault are developed. Besides, all the requirement of a fault tolerant operation, including high phase inductance and negligible mutual coupling between phases are met. Analytical and finite element analysis and comparison case studies are presented.

Modular Multipulse Rectifier Transformers in Symmetrical Cascaded H-Bridge Medium Voltage Drives

A new approach to improve the power quality of high-power medium voltage multilevel drives is presented. A modular transformers strategy in conjunction with modular power electronics cubes is developed. By applying this technology, the input current harmonics decreases to well below the requirement of IEEE 519-1992 while the amount of capacitance installed in the drive is significantly reduced. In addition, by employing modular transformers technology and efficient cooling, power density of the drive is increased by 15%. The input power factor of drive is also improved. This paper details the new approach, analyses, and test results.

Stator flux oriented control of an integrated alternator/active filter for wind power applications

In response to electric energy concerns and power quality issues, a novel, simple and low cost variable speed alternator/active filter for wind power applications is proposed. The proposed integrated alternator/active filter (WAF) is capable of simultaneous generation of optimized green power and improving power quality, which are achieved by canceling the most significant and troublesome harmonics of the utility lines. Power factor correction and reactive power control are the other two significant features of the proposed technology. The novel field oriented method to control this alternator/active filter with higher power density under vector controlled condition is also part of this development. Analysis and simulation as well as experimental results are presented to demonstrate the effectiveness of the proposed integrated alternator/active filter method. The overall complete algorithm has been implemented using the TI DSP controller, TMS320LF2407.

An electromechanical active harmonic filter

In this paper, a new electromechanical active harmonic filter is proposed. The proposed electromechanical harmonic filter is essentially a rotating synchronous machine with suitable modification to its field excitation circuit. It is shown that by injecting: 2/sup nd/, 4/sup th/ and 6/sup th/ harmonics currents into the field winding, 5/sup th/ and 7/sup th/ harmonic currents are generated in the stator winding. By proper control of the field excitation, the proposed electromechanical harmonic filter can compensate for the 5/sup th/ and 7/sup th/ harmonic currents in the electric power distribution system. Simulation and experimental results are presented to demonstrate the effectiveness of the proposed harmonic compensation method. This method is cost effective since it can be applied to existing standby generators in commercial and industrial plants with minimal modification to the excitation circuit.

A New Concentrated Windings Surface Mounted Permanent Magnet Synchronous Machine for Wind Energy Application

The concentrated windings designs are often used in small BLDC motors as well as in AC servomotors due to their shorter end windings and smaller packing size. They are not yet frequently used in larger electrical machines due to concerns about torque density. For example, for a design with slot/ pole ratio of 1.5, the winding factor decreases to 0.866 which the penalty of smaller packaging size is translated to approximately 33.3% more copper losses as compared with a reference machine with winding factor of unity. In this paper, a new concentrated windings surface mounted permanent magnet machine for wind energy application with higher power density is proposed. The proposed machine utilizes 48 poles and 45 slots. The analysis shows while the proposed machine enjoys the privilege of shorter end windings and smaller packaging size, higher torque density is achieved through the winding factor of 0.952. This design with its novel pole and slot configuration, poses zero cogging torque and negligible torque ripple which these features make it a promising technology for wind energy applications. The mathematical model of the proposed machine is developed and is verified with finite element analysis

Harmonic compensation using advanced electric machines

In this paper, a new electromechanical active harmonic filter is proposed. The proposed electromechanical harmonic filter is essentially a rotating asymmetric air gap concentrated winding synchronous machine (AACWSM) with AC and DC excitation field. It is shown that the AACWSM with its unique design can be used to cancel the most dominant current harmonics of the adjacent nonlinear load. The filter is connected in a shunt manner between a nonlinear load and utility. This new AACWSM with its nonlinear current waveform can generate the nonlinear load required harmonics current. By proper control of the field excitation, the proposed electromechanical harmonic filter can compensate for the 5/sup th/ and 7/sup th/ harmonic currents in the electric power distribution system. In addition, 11/sup th/ and 13/sup th/ harmonics magnitudes are also significantly reduced. Analysis and simulation are presented to demonstrate the effectiveness of the proposed harmonic compensation method.

A Novel Multiphase Fault Tolerant Permanent Magnet Motor Drive for Fuel cell Powered Vehicles

This paper presents a novel five-phase fault tolerant interior permanent magnet motor drive with higher performance and reliability for use in fuel cell powered vehicles. A new machine design along with efficient control strategy is developed for fault tolerant operation of electric drive without severely comprising the drive performance. Fault tolerance is achieved by employing a five phase fractional-slot concentrated windings configuration IPM motor drive, with each phase electrically, magnetically, thermally and physically independent of all others. The proposed electric drive system poses with higher torque density, negligible cogging torque, and about plusmn0.5% torque ripple. Power converter requirement are discussed and control strategies to minimize the impact of a machine or converter fault are developed. Beside, all the requirement of a fault tolerant operation, including high phase inductance and negligible mutual coupling between phases are met. Analytical and finite element analysis and comparison case studies are presented.