جستجوی مقالات مرتبط با کلیدواژه "direct torque control" در نشریات گروه "مهندسی دریا"

Direct torque control (DTC) is one of the most effective methods for controlling the induction motor. In direct torque control, motor flux and torque are considered as reference quantities, and are controlled by optimal selection of inverter switching vectors. Using the direct torque control method, you can reduce the field oriented control (FOC) constraints and complexities. The direct torque control has a very fast torque response and is resistant to sudden load variations. In this paper, a complete comparison was made between two methods of classic direct torque control (DTC-CLASSIC) and direct torque control based on space vector pulse width modulation (DTC-SVPWM) using two-level and three-level diode clamp inverters (NPC). Comparison of these methods was carried out using simulation results in MATLAB software. The results of the simulation show that, with respect to the limitation constraint of maximum switching frequency, the DTC-SVPWM applying three-level inverter has less flux and torque ripple and less THD of stator current than the other three.

The direct torque control scheme is a simple configuration structure compared to the Field oriented control. This method is widely used in many applications of motor drive. But the current and torque distortion changes the switching frequency at low speed. The torque ripple causes noise and vibrations and current ripples are in turn responsible for the EMI. The reason of the high current and torque ripple in DTC [4]is the presence of hysteresis comparators together with limited number of available voltage vectors.
In this paper In order to improve the output performances, modified Direct Torque Control scheme is employed with three level inverter. Increasing the number of voltage levels in the inverter without the need for higher nominal rates in individual components, can raise nominal power. voltage source inverters structure, allows them reaches to high voltage with low harmonic without transformer or series and simultaneously switching components. The the harmonic of output voltage waveform significantly reduced if The number of voltage levels go up. The results show that torque and flux ripples are more reduced when three level inverter is employed.