By Topic

Current regulator instabilities on parallel voltage-source inverters

Sign In

Cookies must be enabled to login.After enabling cookies , please use refresh or reload or ctrl+f5 on the browser for the login options.

Formats Non-Member Member
$33 $13
Learn how you can qualify for the best price for this item!
Become an IEEE Member or Subscribe to
IEEE Xplore for exclusive pricing!
close button

puzzle piece

IEEE membership options for an individual and IEEE Xplore subscriptions for an organization offer the most affordable access to essential journal articles, conference papers, standards, eBooks, and eLearning courses.

Learn more about:

IEEE membership

IEEE Xplore subscriptions

4 Author(s)
Thunes, J. ; Rockwell Autom.-Allen-Bradley Co., Mequon, WI, USA ; Kerkman, R. ; Schlegel, D. ; Rowan, T.

Parallel inverters are often used to meet system power requirements beyond the capacity of the largest single structure. They have also been used to reduce harmonics, reduce pulsewidth modulation (PWM) switching frequency and increase available output voltage or frequency. The type of parallel structure depends on the construction of the load motor; the most prevalent are dual three-phase machines, split-phase machines, six-phase machines, and a standard three-phase machine with interphase reactors. Operation of parallel structures presents areas for investigation encompassing analysis, simulation, control, and design. This paper reports on the commissioning of a 775 HP dual-winding three-phase motor with parallel inverters. A simple method of paralleling structures with carrier-based PWM current regulators to independently regulate each inverter's current is employed. Experimental results show a loss of current control that is similar to a random event. The instability between the parallel inverters and the common motor can result in large uncontrolled currents. Simulations established that the reduction in controller gain, as the regulator enters the PWM pulse-dropping or overmodulation region, results in a loss of current control. Experimental results show the loss of current control is the result of an interaction between the parallel inverters through the dual-wound three-phase motor. Modifications were made to the modulator and a two-phase discontinuous controller was employed; the gain characteristic of the two-phase modulator in the overmodulation region extends the dynamic range of the motor drive

Published in:

Industry Applications, IEEE Transactions on  (Volume:35 ,  Issue: 1 )