Parallel operation of voltage source inverters with minimal intermodule reactors

Realization of large horsepower motor drives using parallel-connected voltage source inverters rated at smaller power levels would be highly desirable. A robust technique for such a realization would result in several benefits including modularity, ease of maintenance, n+1 redundancy, reliability, etc. Techniques for parallel operation of voltage source inverters with relatively large load inductance have been well established in the field of UPS systems. This paper presents an approach to such realization using minimal passive components along with an active current balancing strategy for motor drive systems. Analytical models, computer simulations and experimental results are presented.