Method of Direct Torque Control for three-level Voltage Inverter

This paper presents a new method of control based on direct torque control (DTC) strategy. This method is designed to be applied in the control of induction motors (IM) fed with a three-level voltage source inverter (VSI). This type of inverter has several advantages in comparison with standard two-level VSI, such as a greater number of levels in the output voltage waveforms, lower dV/dt, less harmonic distortion in voltage and current waveforms and lower switching frequencies. In the new method, torque and stator flux errors are used together with the stator flux angular frequency to generate a reference voltage vector. Further, practical application and operation of designed converters are documented on experimental results.