PMSM servo drive with resolver

Abstract

Electric motors are found in many applications, may it be in domestic or industrial environments. To operate such motors in a controlled manner, closed loop operation through some control algorithm and feedback is required. This feedback may be in the form of the rotor position or speed, as one may be used to calculate the other. One common type of control applied to Alternating Current (AC) machines is Field-Oriented Control (FOC), also known as vector control. The aim of this dissertation is to interface a Permanent Magnet Synchronous Motor (PMSM), containing a built-in resolver, with a programmable inverter for the implementation of a servo drive. A resolver is a system containing a rotary transformer used to read the angular position of a motor's rotor. Since a resolver is an analogue device, the angular position information it supplies must be digitised such that the micro controller of the inverter can process it. An interface board between the resolver and the inverter was designed for this dissertation. Furthermore, for the implementation of the servo drive, vector control and cascaded control loops were used. The aim of the servo drive is to provide position, speed and current/torque control in either clockwise and anti-clockwise directions. The process of establishing this servo drive and an evaluation of its performance are laid out in this dissertation.