Three-level inverters with direct torque control

Electrical drives with induction motors (IM) and voltage source inverters (VSI), the control of which uses the principle of direct torque control (DTC), ensure accurate and fast torque control with a simple, in principle, control system. Three-level inverters permit the use of double voltage under the same type of switches and reduce IM current and torque distortions. In the paper, the peculiarity of the three-level VSI with DTC and the advantages that can be received in this case are investigated. Algorithms for drive control under high and low frequencies and for middle point voltage control are developed