Dual-zone speed control method for an inverted motor

The aim of the study involved the development of a dual-zone speed control method for a permanent magnet inverted motor applied as a drive for various machines and mechanisms of cyclic action or positional type. In the study, modelling methods were applied based on the contemporary theory of electric drives (using Gorev-Park equations) accompanied by methods derived from classic control theory. As a result, the dual-zone speed control method for an inverted motor was developed based on a previously tested single-circuit control system applicable for speed values below synchronous with full compensation of the stator current along the d longitudinal axis. A method is described for controlling the speed of the value of the stator current superior to synchronous due to incomplete compensation (specified by the coefficient) along the longitudinal axis. A nonlinear model of an inverted motor (based on the Gorev-Park equations) was developed to support a study of its functioning modes at speeds both higher and lower than synchronous. For an engine with specified parameters, the modelling included starting and braking modes, smooth transitions from one speed to another (by selecting the setpoint changing speed), as well as abrupt drops and increases in the load. For the control, a single-circuit control system with a proportional integral differential controller was used. The developed model ensures the selection of the necessary pattern for voltage change along the q transverse axis of the studied motor stator, thus preventing the current overload of the frequency converter during the motor operation both above and below the synchronous speed. Dynamic modes of the "frequency converter - inverted motor" closed-loop system were investigated in the Simulink environment of the Matlab package. The obtained equations of static modes support a determination of the restrictions on speed and torque for two versions of the drive. Thus, the developed inverted motor control system is simpler than the classic dual-circuit system that lacks frequency converter disconnection during overloads.

inverted motor, incomplete compensation of stator current along longitudinal axis, dual-zone speed control, frequency converter, drive