Coupling induction motors to improve the energy conversion process during balanced and unbalanced operation

• The steady-state performances of cascaded induction motors operating under balanced and unbalanced supply voltages are studied.
• Small sizes induction motors are cascaded instead of one big size induction motor to improve the energy conversion process.
• The coupled machines are analyzed using the method of symmetrical components and MATLAB/Simulink software.
• Coupling of the induction motors with the DC motors to examine the improvement on the electromagnetic torque.
• The results indicated that cascading the electrical machines improves the energy conversion process.

This paper assesses the steady-state performance of cascaded IMs (induction motors) operating under voltage unbalance. Small sizes induction motors are connected in cascade instead of one big size induction motor to improve the electromagnetic system and to make the energy conversion process more efficient during both balanced and unbalanced operation. The two mechanically coupled induction motors could have the same ratings or different ratings. The paper analyzes the coupled machines system using the method of symmetrical components and MATLAB/Simulink software. The definition of the voltage unbalance using CVUF (complex voltage unbalance factor) is used. Coupling of induction motors with DC (direct current) motors is examined to investigate the effect of cascading on the electromagnetic torque of the entire set. A comparison of the effect of the unbalanced voltage on single and cascaded machines is illustrated. The purpose of such comparison is to determine which one has the best performance during the balanced and unbalanced operations. Furthermore, this paper assesses the impact of connecting induction motors in cascade on the energy conversion process.