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PRESENTED BY

R. RADHIKA

B. USHA RANI

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ABSTRACT

Permanent magnet synchronous motor (PMSM) has been widely used in high performance drive applications for its advantages such as compactness, high efficiency, reliability and suitability to environment. Due to its high power density and smaller size, PMSM has evolved as the preferred solution for speed and position control drives on machine tools and robots. A Permanent Magnet Synchronous Motor (PMSM) is a motor that uses permanent magnets to produce the air gap magnetic field rather than using electromagnets. These motors have significant advantages, attracting the interest of researchers and industry for use in many applications. Permanent magnet synchronous motors are widely used in low and mid power applications such as computer peripheral equipments, robotics, adjustable speed drives and electric vehicles.

In order to overcome the inherent coupling effect and the sluggish response of scalar control the vector control is employed. By using the vector control, the performance of the AC machine can be made similar to that of a DC machine. In this work to achieve high performance the vector control of the Permanent magnet synchronous motors drive is employed. The simulation of PMSM is developed using SIMULINK. The effectiveness of the proposed control method is verified by simulation based on MATLAB. The simulation results along with the case study is presented and explained in detail.

1 INTRODUCTION

1.1 INTRODUCTION

With the advent of switching power transistor and silicon controlled rectifier devices in later part of 1950’s, and the replacement of the mechanical commutator with an electronic commutator in the form of an inverter was achieved. These two developments have contributed to the development of the PM synchronous and brushless DC machines. A Permanent Magnet Synchronous Motor (PMSM) is a motor that uses permanent magnets to produce the air gap magnetic field rather than using electromagnets. These motors have significant advantages, attracting the interest of researchers and industry for use in many applications.

Permanent magnet synchronous motors are widely used in low and mid power applications such as computer peripheral equipments, robotics, adjustable speed drives and electric vehicles.

The growth in the market of PMSM motor drives has demanded the need of simulation tool capable of handling motor drive simulations. Simulations have helped the process of developing new systems including motor drives, by reducing cost and time. Simulation tools have the capabilities of performing dynamic simulations of motor drives in a visual environment so as to facilitate the development of new systems.

In this work, the simulation of PMSM is developed using SIMULINK. The vector control is one of the high performance control strategies for ac machine. The aim of the project is to study the implementation of the vector control in Permanent Magnet Synchronous Motor (PMSM).

1.2 OBJECTIVES

The objectives of the project are

i) To stimulate the vector control of permanent magnet synchronous motor.

ii) To analyze the simulation results.

1.3 RESEARCH METHODOLOGY

The research work is undertaken in the following stages:

i) Studied the application of MATLAB/SIMULINK.

ii) Studied the theoretical basis of the vector control for permanent magnet synchronous motor drives.

iii) Simulation of vector control of permanent magnet synchronous motor is performed using SIMULINK.

iv) Analyzed the simulation results.

1.4 SCOPE OF PROJECT

The scope of work for this project

i) PMSM with saliency is considered.

ii) Simulation is performed using MATLAB/SIMULINK.

iii) The performance of vector control of PMSM is discussed based on the simulation results.

CHAPTER-II

LITERATURE SURVEY AND PROBLEM DEFINITION

2 LITERATURE SURVEY AND PROBLEM DEFINITION

2.1 INTRODUCTION

A literature survey forms the basis on which a project can be built or developed. It forms the core to which ideas can be added and developed into a comprehensive system, which will be able to cover the deficiencies of some of the existing systems.

This chapter deals with the data and information accumulated after referring to many books, articles and technical papers written by well-known authors and the problem definition of the project.

2.2 LITERATURE SURVEY

[1] T. Sebastian, G. Slemon, and M. Rahman, "Modeling of permanent magnet

synchronous motors," Magnetics, IEEE Transactions on, vol. 22, pp. 1069-1071,

1986.

[2] T. M. Jahns, G. B.Kliman, and T. W. Neumann, "Interior Permanent-Magnet

Synchronous Motors for Adjustable-Speed Drives," Industrial Applications, IEEE

Transactions on, vol. IA-22, pp. 738-746, 1986.

[3] P. Pillay and R. Krishnan, "Modeling of permanent magnet motor drives," Industrial Electronics, IEEE Transactions on, vol. 35, pp. 537-541, 1988.

[4] P. Pillay and R. Krishnan, "Modeling, simulation, and analysis of permanent-magnet motor drives. I. The permanent-magnet synchronous motor drive," Industry

Applications, IEEE Transactions on, vol. 25, pp. 265-273, 1989.

[5] B. K. Bose, Modern power electronics and AC drives: Prentice Hall, 2002

[6] A. H. Wijenayake and P. B. Schmidt, "Modeling and analysis of permanent magnet synchronous motor by taking saturation and core loss into account," 1997.

[7] K. Jang-Mok and S. Seung-Ki, "Speed control of interior permanent magnet

synchronous motor drive for the flux weakening operation," Industry Applications,

IEEE Transactions on, vol. 33, pp. 43-48, 1997.

[8] Weera Kaewjind and Mongkol Konghirun “Vector Control Drive of Permanent Magnet Synchronous Motor Using Resolver Sensor” ECTI transactions on electrical eng., electronics, and communications vol.5, no.1 february 2007.

PM motor drives have been a topic of interest for the last twenty years. Different authors have carried out modeling and simulation of such drives. Some of them have been discussed in detail.

[1] T. Sebastian, G. Slemon, and M. Rahman, "Modeling of permanent magnet

synchronous motors"

In 1986 Sebastian, T., Slemon, G. R. and Rahman, M. A. [1] reviewed permanent magnet synchronous motor advancements and presented equivalent electric circuit models for such motors and compared computed parameters with measured parameters. Experimental results on laboratory motors were also given.

[2] T. M. Jahns, G. B.Kliman, and T. W. Neumann, "Interior Permanent-Magnet Synchronous Motors for Adjustable-Speed Drives,"

In 1986 Jahns, T.M., Kliman, G.B. and Neumann, T.W. [2] discussed that interior permanent magnet (IPM) synchronous motors possessed special features for adjustable speed operation which distinguished them from other classes of ac machines. They were robust high power density machines capable of operating at high motor and inverter efficiencies over wide speed ranges, including considerable range of constant power operation. The magnet cost was minimized by the low magnet weight requirements of the IPM design. The impact of the buried magnet configuration on the motor’s electromagnetic characteristics was discussed. The rotor magnetic saliency preferentially increased the quadrature-axis inductance and introduced a reluctance torque term into the IPM motor’s torque equation. The electrical excitation requirements for the IPM synchronous motor were also discussed. The control of the sinusoidal phase currents in magnitude and phase angle with respect to the rotor orientation provided a means for achieving smooth responsive torque control. A basic feed forward algorithm for executing this type of current vector torque control was discussed, including the implications of current regulator saturation at high speeds. The key results were illustrated using a combination of simulation and prototype IPM drive measurements.

[3] “Modeling, Simulation, And Analysis of Permanent-Magnet Synchronous Motor Drive” by P. Pillay and R. krishnan

In 1988 Pillay and Krishnan, R.[3] presented PM motor drives and classified them into two types such as permanent magnet synchronous motor drives (PMSM) and brushless DC motor (BDCM) drives. The PMSM has a sinusoidal back EMF and requires sinusoidal stator currents to produce constant torque while the BDCM has a trapezoidal back EMF and requires rectangular stator currents to produce constant torque. The PMSM is very similar to the wound rotor synchronous machine except that the PMSM that is used for servo applications tends not to have any damper windings and excitation is provided by a permanent magnet instead of a field winding. Hence the d, q model of the PMSM can be derived from the well known model of the synchronous machine with the equations of the damper windings and field current dynamics removed. Equations of the PMSM are derived in rotor reference frame and the equivalent circuit is presented without dampers. The damper windings are not considered because the motor is designed to operate in a drive system with field-oriented control. Because of the non-sinusoidal variation of the mutual inductances between the stator and rotor in the BDCM, it is also shown in this paper that no particular advantage exists in transforming the abc equations of the BCDM to the d, q frame. As an extension of his previous work, Pillay, P. and Krishnan, R. in 1989 presented the permanent magnet synchronous motor (PMSM) which was one of several types of permanent magnet ac motor drives available in the drives industry. The motor had a sinusoidal flux distribution. The application of vector control as well as complete modeling, simulation, and analysis of the drive system were given. State space models of the motor and speed controller and real time models of the inverter switches and vector controller were included. The machine model was derived for the PMSM from the wound rotor synchronous motor. All the equations were derived in rotor reference frame and the equivalent circuit was presented without dampers. The damper windings were not considered because the motor was designed to operate in a drive system with field-oriented control. Performance differences due to the use of pulse width modulation (PWM) and hysteresis current controllers were examined. Particular attention was paid to the motor torque pulsations and speed response and experimental verification of the drive performance were given.

[4] P. Pillay and R. Krishnan, "Modeling, Simulation, And Analysis Of Permanent-Magnet Motor Drives".

As an extension of his previous work, Pillay, P. and Krishnan, R. in 1989 [4] presented the permanent magnet synchronous motor (PMSM) which was one of several types of permanent magnet ac motor drives available in the drives industry. The motor had a sinusoidal flux distribution. The application of vector control as well as complete modeling, simulation, and analysis of the drive system were given. State space models of the motor and speed controller and real time models of the inverter switches and vector controller were included. The machine model was derived for the PMSM from the wound rotor synchronous motor. All the equations were derived in rotor reference frame and the equivalent circuit was presented without dampers. The damper windings were not considered because the motor was designed to operate in a drive system with field-oriented control. Performance differences due to the use of pulse width modulation (PWM) and hysteresis current controllers were examined. Particular attention was paid to the motor torque pulsations and speed response and experimental verification of the drive performance were given.

[5] “Modern Power Electronics And Ac Drives” by B. K. Bose

Bose, B. K., in 2001 [5], presented different types of synchronous motors and compared them to induction motors. The modeling of PM motor was derived from the model of salient pole synchronous motor. All the equations were derived in synchronously rotating reference frame and was presented in the matrix form. The equivalent circuit was presented with damper windings and the permanent magnet was represented as a constant current source. Some discussions on vector control using voltage fed inverter were given.

[6] “Modeling And Analysis Of Pmsm” by Wijenayake, A.H. and Schmidt, P.B.

The paper in 1997 by Wijenayake, A.H. and Schmidt, P.B. [6], described the development of a two-axis circuit model for permanent magnet synchronous motor (PMSM) by taking machine magnetic parameter variations and core loss into account. The circuit model was applied to both surface mounted magnet and interior permanent magnet rotor configurations. A method for on-line parameter identification scheme based on no-load parameters and saturation level, to improve the model, was discussed in detail. Test schemes to measure the equivalent circuit parameters, and to calculate saturation constants which govern the parameter variations were also presented.

[7] K. Jang-Mok and S. Seung-Ki, "Speed control of interior permanent magnet

synchronous motor drive for the flux weakening operation,"

In 1997 Jang-Mok, K. and Seung-Ki, S. [7], proposed a novel flux-weakening

scheme for an Interior Permanent Magnet Synchronous Motor (IPMSM). It was implemented based on the output of the synchronous PI current regulator reference voltage to PWM inverter. The on-set of flux weakening and the level of the flux were adjusted inherently by the outer voltage regulation loop to prevent the saturation of the current regulator. Attractive features of this flux weakening scheme included no dependency on the machine parameters, the guarantee of current regulation at any operating condition, and smooth and fast transition into and out of the flux weakening mode. Experimental results at various operating conditions including the case of detuned parameters were presented to verify the feasibility

of the proposed control scheme.

[8] Weera Kaewjind and Mongkol Konghirun “Vector Control Drive of Permanent Magnet Synchronous Motor Using Resolver Sensor”

The rotor position is necessary to achieve the vector control drive system of Permanent Magnet Synchronous Motor (PMSM). In this paper, the resolver sensor detecting the rotor position of PMSM is fo- cused. The outstanding features of this sensor are its robust structure and noise insensitivity. The resolver algorithm is proposed and implemented in the vector control drive system of PMSM. The pro posed scheme has been verified by both simulation and experiment using MATLAB/Simulink and the TMS320F2812 based digital controller, respectively. The proposed resolver algorithm has been verified in the current controlled drive system of PMSM. Both simulation and experimental results are presented. According to these results, the re-solver algorithm can force the angle error to zero. Thus, the computed angle can eventually match with the actual rotor angle. Then, the correct rotor speed computation is guaranteed. In the future works, this algorithm will be extensively tested in the speed controlled drive system of PMSM.