PERFORMANCE ANALYSIS OF HIGH SPEED PERMANENT MAGNET SYNCHRONOUS MOTOR DRIVE

Abstract

The application demand of electric motors is increasing rapidly with increasing technological advancement. According to the technological progress adjustable speed drives are preferred over constant speed drives because of several reasons energy saving, velocity or position control for good transient response etc. The present thesis based on i) design of interior permanent magnet synchronous motor (IPMSM), ii) implementation of Vector control in terms of a) zero direct-axis current control strategy (ZDAC) and b) maximum torque per ampere control (MTPA), iii) simulation of drives and control with constant torque and flux weakening region. Permanent Magnet Synchronous Motors (PMSM) are widely used with current-controlled voltage source inverters for industrial and traction applications, because of their high power density, relatively small rotor inertia and high efficiency. In industrial applications, especially servo drives a constant torque operation is desired; while in case of traction applications, both constant torque and constant power operations are necessary. With the emergence of new permanent magnet material, modem PMSM has been developed to the direction with high power and speed. Constant torque and power operation can be achieved with flux weakening control. An analytical software (SPEED PC-BDC 6.5) is used to design geometrical dimension of machine and to simulate the machine static and dynamic behavior. The rotor configuration considered in this study is interior permanent magnet type. A new current regulation control algorithm proposed that provides drives to operate in constant torque and flux weakening region with optimum current control. The control adjusts q and d-axis current command based on commanded torque considering speed and dc link voltage. As a first step wtowards the objective of this thesis, a PMSM motor, its characteristics and its behavior when fed form a voltage source inverter with current control has been studied. The control is performed by regulating the flow of current through the stator of the motor. Hysteresis current controller has been implemented to generate gate signals for the inverter. Vector controller has been designed in terms of i) zero direct-axis current control strategy (ZDAC) and ii) maximum torque per ampere (MTPA). The drives performance also has been analyzed with PI controller for both control strategy (ZDAC and MTPA).The simulation study have been carried out for the drives in below base speed operation, above base speed operation with load variation.