Voltage and Current Limited Maximum Torque Algorithm of SPMSM in Traction Applications

permanent magnet synchronous machines (PMSMs) are widely used in traction applications on account of higher efficiencies, higher torque and power densities. Due to the reluctance torque component, internal PMSMs are commonly found; however, with the evolution of axial-flux PMSMs, machines with surface-mounted magnets are gaining relevancy. This paper developed a wide-speed operation algorithm for surface PMSMs that obtains the maximum mechanical torque possible while respecting the voltage and current constraints of the machine for any speed, named voltage and current limited maximum torque (VCLMT) algorithm, with an adjustable reference that produces a torque that ranges from zero to the maximum possible in all four torque-speed quadrants. The proposed VCLMT is verified and compared through both simulation and experiment.