MODELLING AND TESTING OF SYNCHRONOUS MOTORS WITH PERMANENT MAGNETS

Abstract

Permanent magnet synchronous motors (PMSM) have been known for a long time. In Ukraine, this type of motors is not used widely enough. Synchronous motors require less energy to provide sufficient performance than the well-known induction motor. It shows what PMSM require control equipment to ensure smooth rotor start, motion and stop. 
Starting methods such as the use of pony motors, starting with external drives, or the use of specialized starting equipment such  as synchronous motor starters or static frequency converters are used to overcome these problems.
In the case of a permanent magnet synchronous motor, one of the fundamental problems is starting from an unknown position. 
Starting movement from an unknown position can lead to a temporary reverse movement of the rotor until the fields of the rotor and stator are aligned. Three schemes like Volt-Frequency (VF), Sensorless Vector Control (SVC) and Vector Control (VC) to control motors are currently  known. But only the control of the encoder at VC control type ensures an adequate start of the synchronous motor. PMSM allow you to  archive a constant increase in speed, a quick response to the rotor load. The output torque of the PMSM is automatically regulated by the supply voltage and current with stable rotations. 
The article shows results of comparing existing PMSM motor with an encoder with use of Vector Control Driver and virtual model  of PMSM with a variable load. The high-speed response of the frequency converter together with the control system ensures a constant rate  of increase in the motor speed regardless of load changes. Thus, the synchronous motor maintains stable mechanical characteristics  regardless of changes in load and rotation frequency. At the same time, the motor voltage and current are dynamically adjusted to ensure 
the desired output performance