METHOD OF SUPPLY VOLTAGE REGULATION OF MULTILEVEL SELF-COMMUTATED VOLTAGE INVERTER Russian patent published in 2008 - IPC H02M5/451 

FIELD: electricity.

SUBSTANCE: method can be realised in frequency converter containing two or more output-uncoupled three-phase thyristor bridge rectifiers, two or more DC links containing capacitors; two or more self-commutated voltage inverter stages and control system. To achieve technical result that is voltage ripple minimisation on DC links capacitors within intervals without power consumption with one or another stage, control angle of relative rectifier increases from current value α_rated to maximum α_max=90 electrical degrees for inductive loading and α_max=120 electrical degrees for resistive loading. As a result of voltage ripple caused by capacitor recharge without power consumption of energy is neutralised.

EFFECT: method does not require instant converter currents and voltages tracing and is effective for low and extremely low frequency operation.

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