Optimum current reference generation algorithm for four quadrant operation of PMSMS drive system without regenerative unit

This paper proposes an algorithm to generate the optimum d- and q-axes current references for PMSMS (permanent magnet synchronous motor with sinusoidal excitation) drive system for wide speed range that is fed by frequency converter that has no regenerative unit. The algorithm offers optimum torque capability for PMSMS despite significant changes in the dc link voltage and machine parameters and it can be used in field oriented control of PMSMS with or without mechanical sensors, but also in the scalar control algorithm (without motor current measurement sensors) with good results. The algorithm uses the maximum torque-per-ampere (MTPA) control method, in the constant-torque region, to generate the d- and q-axes current references and it identifies also when the machine enters the field weakening region and determines the optimum d- and q-axes current references depending on the field-weakening region (region I, and II). Experimental steady-state performance results and dynamic performance results are examined by several drive tests with a PMSMS.