Alternating Current Electric Generator Machine Inverters in a Parallel Power Sharing Connection

This paper covers the theoretical background as well as chosen selected experimental results obtained for two AC current generators connected to voltage source inverters working in parallel. Inverters were connected in parallel via their intermediate direct current circuits by means of auctioneering diodes which select higher voltage source, and then directly to a DC power network. The selected real-time control algorithm for a digital signal processor and a field programmable gate array was used to achieve the proper excitation of two different types of alternators: a squirrel-cage generator denoted as and a self-excited synchronous generator. Another task for the excitation system was to maintain the proper level of direct current link voltage and stable power distribution between both generators rotating at changing speeds. The windings of alternators were fed with the use of so-called machine side inverters. The asynchronous generator was a voltage source inverter driven with the use of a sensorless multiscalar algorithm based on the current machine model, whereas the self-excited synchronous generator worked on the field oriented control principle. To prove the robustness of the chosen algorithm, different types of load were applied while during the parallel work of the generators and inverters.