CASCADE FREQUENCY CONVERTER WITH INCREASED NUMBER OF OUTPUT VOLTAGE LEVELS Russian patent published in 2022 - IPC H02M5/458 H02P27/06 

FIELD: electricity.

SUBSTANCE: present invention relates to electric frequency converters of powerful electric drives with high quality of output voltage and can be used as a device for controlling the moment, speed or power on the shaft of the actuating electric motor of almost any AC electric drive. Such a frequency converter will make it possible to significantly increase the service life of the electric machine, since the windings are supplied with almost sinusoidal voltage, which considerably prolongs the service life of the insulation. At the same time currents consumed by the electric machine will be almost sinusoidal, which will positively affect the value of pulsation of the electromagnetic moment, and consequently, vibration-noise characteristics of the electric machine and the service life of its bearings. Delivered technical result is achieved by the fact that the cascade frequency converter contains a power matching multi-winding transformer, the secondary windings of which are connected by a star and contain a zero-point output, and as level elementary cells single-phase frequency converters are used, which are made using three-level voltage inverters.

EFFECT: increase in the number of levels of instantaneously synthesized voltage and frequency of the modulated voltage at the output of the cascade frequency converter, as a result, the quality of the voltage at the load is increased, the dispersion of voltage and current is significantly reduced, and also the rate of increase of voltage (dU/dt) on the load is reduced, which helps to avoid resonances of electromagnetic processes.

6 cl, 8 dwg