ABSTRACT
The control technology of complicated dynamic objects on the basis of automated electric DC and AC drives with the consecutive correction of characteristics occupies an important place in the modern approach to the optimization of dynamic work modes of machines and installations (Boldea 2006; Khilov 2004; Pivnyak 2005). The characteristic feature of such systems is the presence of a thyristor rectifier for a DC drive and a voltage transistor autonomous inverter with the amplitude-pulse modulation for an AC drive, as well as special transmissions which transmit torque from the engine to the executive device. At the same time, masses and elasticities of separate units of the mechanical system can be lumped and distributed (drilling rigs, excavators, band conveyors, mine winder installations etc (Khilov & Plakhotnik 2004; Pivnyak 2003). Such control objects have low natural frequencies. The DC drive systems, due to the inertia of a thyristor converter and mechanical inertia of motor armature are low frequency filters of good quality having a bandwidth of up to 50 rad/s. The AC drive systems, due to lower mechanical inertia of a
motor and higher switching frequency of a pulseimpulse electrical modulator, have a bandwidth of up to 200 rad/s. Therefore, the modernization of the electric drive with the replacement of a DC system by an AC one, greatly changes the work dynamics of the electromechanical installation (Khilov 2006).
