Development of combined vector and Direct Torque Control methods for independent two induction motor drives

Abstract

Many applications use two or more motors operating in parallel configuration by using one variable speed drive. This system is able to control these multiple motors at the same desired motor speed operation which provide advantages in terms of components and cost reduction. However, the system is not able to control each motor separately if it is desired to operate at different speeds and it also cannot withstand the load disturbance. To address this problem, the design of combined Vector Control-Direct Torque Control (DTC) methods is proposed and their performance is investigated for the case of independent controlled two induction motors fed by single Five Leg Inverter (FLI) method. Double Zero Sequence (DZS) Injection Method Space Vector Pulse Width Modulation (SVPWM) scheme is used for the FLI. Simulation results fromthe Simulink/Matlab that verify the validity of the method are also included. The results show the ability of the proposed method to control motor speed independently under forwardreverse step speed command and load disturbance condition.

A Combined Control Scheme of Direct Torque Control and Field-Oriented Control Algorithms for Three-Phase Induction Motor: Experimental Validation

“…To verify the feasibility and the effectiveness of the proposed algorithm, its performance is compared with previous and up-to-date related approaches in the literature review, which are specified in the following work reference [24][25][26][27][28][29][30][31][32][33][34][35][36]. Table 3 represents seven work references deemed to be worthy of comparison with the proposed control scheme.…”

“…Table 3 represents seven work references deemed to be worthy of comparison with the proposed control scheme. The most relatable case studies towards the proposed control scheme are in [24,31], while the rest of the articles clearly perform worse than the proposed algorithm because they all operate at a variable switching frequency, as well as are unable to generate a large torque beyond the critical torque. Study [24] contained four optional gains, which created difficulty in the synthesis process with the changing operating conditions as well as the need for orientation over the whole range of the operation.…”

“…In addition, the lack of simplicity in terms of orientation within the transient state and nominal torque range. Study [31] showed that the system suffers from a slow torque transient, the switching frequency is not always constant, and its incapacity to generate torque above the critical torque. The comparison pointed out that the proposed method has provided valuable results compared to the corresponding literature in terms of low flux and torque ripples, high torque production, constant switching frequency, and simplicity.…”

“…To solve this problem, the method in [30] was proposed to employ an artificial neural network instead of the switching table and the hysteresis comparators, which could provide the appropriate logic outputs for the inverter. The design of combined VC-DTC methods was proposed and investigated for two independently controlled induction motors fed by a single Five Leg Inverter (FLI) [31]. However, the difficulty of manually tuning six PI controllers evolved rather than the shared leg of the inverter for two motors, which is the main drawback of this technique.…”