METHOD FOR CONTROL OF CONNECTED IN PARALLEL INVERTERS Russian patent published in 2009 - IPC H02M7/493 

FIELD: electricity.

SUBSTANCE: invention refers to converter technique and can be used in devices and systems of alternating current uninterrupted power supply systems and in automatic devices and instrumentation. Method for connected in parallel inverter control consists in the following: output currents of the first channel and the second pulse channel of electric energy conversion connected in parallel are added on common load; control signal is fed to the input of the first channel; output current of the first channel is measured and used to control the second pulse channel with the help of which pulses of positive or negative polarity filtered using reactor coil are switched into load. The novelty of suggested control method consists in using voltage inverter with pulse-width modulation which output voltage is filtered using for example L-shaped filter as the first converter. The carrier frequency of pulse-width conversion of the second inverter electric energy is selected less than for the first inverter; output current of the second inverter is measured and part of negative feedback signal, proportional to this current, is subtracted from control signal thus presetting transfer ratio for current of the second inverter. In parallel to the first and the second inverter, the third, the fourth inverter and so on, output voltages of which are filtered using corresponding reactor coils. To control the third, the fourth and so forth inverters the signal of first inverter output current is also used. Carrier frequencies of the third, the fourth and so forth inverters are selected less than for the first inverter. Inverter current transfer ratios are set using corresponding depth of negative current feedback. Carrier frequencies of pulse-width modulation for the second, the third, the fourth and so forth inverters referred to as driven are generated identical, and pulse phases are set with offset sufficient for excluding simultaneous operation of their switches. When load currents are less than sensitivity threshold of driven inverters, their pulses are blocked, and when load current increases the invertors are activated again.

EFFECT: increase in efficiency factor, reliability of connected in parallel inverters in uninterrupted power supply systems with alternating current output.

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