Analysis and Simplified Representations of Rectifier - Inverter Reluctance-Synchronous Motor Drives

Methods of analyzing six-step and pulse-width- modulated (PWM) types of rectifier-inverter reluctance-synchronous motor drive systems are set forth. In this development the harmonic components due to the switching of the rectifier are neglected, and the operation of the inverter is expressed in a reference frame rotating in synchronism with the fundamental frequency of the inverter output voltages. In the case of the PWM inverter, the Fourier series expansion of a pulse train is used to express the operation of this type of inverter in the synchronously rotating reference frame. Simplified representations are obtained by neglecting the harmonics due to the inverter switching. These simplified representations are verified by comparing the results obtained from a computer study using these representations to those obtained using a detailed simulation of the system. The analysis set forth and the simplified representations that are developed can be used to determine small-displacement system stability, as well as provide a simple and direct technique of predicting the dynamic and steadystate performance of these involved systems. Moreover, the equations established for the PWM inverter can also be used in conjunction with an induction motor drive.