Design of Boomerang-Type LS-SynRM for Achiving IE4 Efficiency

In induction motors (IMs), rotor copper losses occur due to the induced current generated by the difference between the rotor speed and the input power frequency, accounting for approximately 25% of total losses. In contrast, the Line Start Synchronous Reluctance Motor (LS-SynRM) experiences a significant reduction in rotor copper losses once it reaches synchronous speed, as no induced current from the fundamental component of the load current is generated, making LS-SynRM more advantageous for efficiency compared to IMs. However, the harmonic components of the load current can still induce rotor currents, which may reduce efficiency. This paper focuses on maximizing the efficiency of a 4-pole, 37kW LS-SynRM through the design of its rotor and stator windings, analyzing the causes of rotor copper losses, and exploring methods to reduce them.