How power supply parameters affect the resonant state of oscillatory BLDC drives

Periodic-motion electric machines are used in various electromechanical facilities designed for various purposes; the operating properties of such machines are researched to construct high-performance oscillatory drives generating both linear and angular motion. One specific kind of such drives is gearless electrical drives which generate oscillatory motion by applying different modulations to power the phase voltages of the motor. Based on mathematical model analysis of a valve actuator, we define a procedure for calculating its oscillatory-motion output parameters with due account of control functions, the electric machine parameters, and the load. It is shown that when finding the oscillating electromagnetic torque in a BLDC motor for engineering calculations, it is enough to take into account only the constant terms in its damping component. We have thus formulated an expression for finding the oscillation amplitude of the moving BLDC element, which has enabled us to establish the possibility of controlling the eigen-frequency of the BLDC motor by altering the amplitude of one of the phase voltages. Such oscillatory motion has been simulated by means of MathCAD 2000 with the simulation results being presented here and demonstrating how resonance-state operation can be attained per the algorithm developed. The obtained analytical relations make up the theoretical basis for computing not only output parameters, but also the operating properties of oscillatory electrical drives. They can be recommended for the evaluation of dynamic indexes and energy data for oscillatory motion.