PARALLEL STRUCTURE OF THREE-PHASE MULTI-LEVEL PWM CONVERTERS

摘要

The present invention relates to a parallel structure of three-phase multi-level PWM converters which are suitable for distributed power supplies, and systems for grid-connected power generation with renewable energies, charging and discharging and energy storage therefor and the like. Then present invention includes more than two three-phase multi-level PWM converters and control circuit units thereof, a digital signal processor and a three-phase alternating current power supply circuit; and further includes a common unified voltage regulator, the unified voltage regulator consisting of a voltage sampling circuit, a voltage sensor, a third adder and an external loop voltage PI regulator, the voltage sampling circuit being connected in parallel to a load R_L. The advantages of the present invention are as follows: the energy flow direction consistency problem of each three-phase multi-level PWM converter when operating in parallel is solved, the generation of a loop current is avoided, and at the same time the problem of equal current when each three-phase multi-level PWM converter operates in parallel is solved. The present invention is suitable for scenarios in which high power and scaled power electronics conversion is applied.