Optimum machine parameters and design of inverter-driven synchronous motors for wide constant power operation

The synchronous motors driven by the current regulated voltage-source PWM inverter can be modeled by the same d-q reference frame circuit and generally analyzed where the machine parameters depend on the rotor configuration. The effects of machine parameters and the operating characteristics with respect to several types of synchronous motors, including synchronous reluctance motors, surface permanent magnet synchronous motors and interior permanent magnet synchronous motors, are examined in this paper. The optimum current vector producing the maximum output power at any operating speed is derived, and it is shown that the output power versus speed characteristics depend only on the value of E₀-X_d in per unit form. The selection of machine parameters and design are discussed in order to obtain the desired output characteristics