15-01-2013, 03:39 PM
VECTOR CONTROL DRIVES OF PERMANENT MAGNET SYNCHRONOUS MOTOR
VECTOR CONTROL.pptx (Size: 388.01 KB / Downloads: 35)
OBJECTIVE
Nowadays, PMSM is designed not only to be more powerful but also with lower mass and lower moment of inertia.
Due to its high power density and smaller size, PMSM has in recent years evolved as the preferred solution for speed and position control drives on machine tools and robots.
In vector control drive, the highly accurate position from position sensor is required to transform the abc variables to the dq variable in the synchronously rotating reference frame aligned with the rotor flux linkage vector.
It deals with the selection of the simulation tool for dynamic simulation of motor drives.
INTRODUCTION
This feature is important to gain the maximum starting torque in such drive system.
Description of the Drive System
This deals with the description of the different components such as permanent magnet motors, position sensors, inverters and current controllers of the drive system..
Permanent Magnet Synchronous Motor Drive System: The motor drive consists of four main components, the PM motor, inverter, control unit and the position sensor.
Permanent Magnet Synchronous Motor: 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.
Position Sensor: Operation of permanent magnet synchronous motors requires position sensors in the rotor shaft when operated without damper winding. The need of knowing the rotor position requires the development of devices for position measurement. There are four main devices for the measurement of position, the potentiometer, linear variable differential transformer, optical encoder and revolvers. Depending on the application and performance desired by the motor a position sensor with the required accuracy can be selected
MODELING OF PM DRIVE SYSTEM
This deals with the detailed modeling of a permanent magnet synchronous motor. Field oriented control of the motor in constant torque and flux-weakening regions are discussed.
Detailed Modeling of PMSM: Detailed modeling of PM motor drive system is required for proper simulation of the system. The d-q model has been developed on rotor reference frame. At any time t, the rotating rotor d-axis makes and angle θr with the fixed stator phase axis and rotating stator mmf makes an angle α with the rotor d-axis. Stator mmf rotates at the same speed as that of the rotor.
The model of PMSM without damper winding has been developed on rotor reference frame using the following assumptions:
1) Saturation is neglected.
2) The induced EMF is sinusoidal.
3) Eddy currents and hysteresis losses are negligible.
4) There are no field current dynamics.
ADVANTAGES
The PMSM also has advantages when compared to an AC induction motor.
PMSM generate the rotor magnetic flux with rotor magnets, so achieve higher efficiency.
Compared with a DC motor, the PMSM misses a
commutator and so it is more reliable than the DC motor
APPLICATIONS
PMSMs are very popular in a wide array of applications.
Therefore PMSM are used in
Electric and Hybrid vehicles,
Refrigerators,
Washing machines,
Dishwashers,
High-end pumps,
Fans and in other appliances, which require high reliability and efficiency.
CONCULSION
In this paper, the proposed resolver algorithm has been verified in the current controlled drive system of PMSM. Both simulation and experimental results are presented. According to thus results, the resolver 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.