Influence of DC-link fluctuations on three-phase induction motor drives

Modern induction machine (IM) drives are subject to a variety of system perturbations, possibly compromising machine performance characteristics such as speed, torque, and load current. This paper presents a three-phase induction motor drive system with an active IGBT rectifier, i.e. an active front end (AFE). The AFE converts the AC line input into a controlled DC-link voltage which is then used as input into a three-phase IM drive, based on an IGBT converter. A reconfigurable IM drive, i.e. the inverter, is controlled by the conventional PWM and space vector PWM based methods. This paper investigates the influences of the DC-link variations on the IM drive under each of these modulation strategies. A simulated drive is verified via an experimental test bed, and is then used to further study more extreme DC-Link fluctuations; specifically, variations 10 percent above and below the experimental value of 670 V. Phase current and voltage THD and spectra will be calculated to evaluate the fluctuations influence on performance characteristics. This system will be verified based on the control system rapid prototyping environment of dSPACE.