Potential of AC drives with semi-closed control

Control systems are considered for synchronous and asynchronous AC drives that combine advantages of open-loop and closed-loop systems. They operate as open-loop systems for quick processes and as closed-loop ones for slow processes. Application field covers mainly high-power MV controlled drives. In this field known methods don´t provide desired results because of specifics of high-power frequency converters. These are: low and sometimes unlimitedly low frequency of system closing, resonant stator circuits. Considered systems are composed on the base of methods of non-linear multi-connected subordinate control systems those are supplemented by principle of semi-closed control. These provide high quick-responsibility and high accuracy of control, type dynamics. As an example the synchronous drive Is considered on the base of PWM CSI. Simulation showed that results are suitable for most of high-power controlled drives including most dynamical ones.