METHOD FOR CONTROLLING PARALLEL RUNNING OF FOUR-QUADRANT CONVERTERS Russian patent published in 2007 - IPC H02M7/77 

FIELD: electrical engineering; controlling input converters of alternating-current consists to improve input-current characteristics.

SUBSTANCE: supply current consumed by parallel-running four-quadrant converters is generated by way of control in which semiconductor power apparatuses are changed over in phase modules of four-quadrant converters basing on relative pulse duration of pulse-width voltage modulation; each converter is controlled with fixed phase shift of modulation. Odd number of parallel-running converters is entered; rated modulated value is introduced for odd number of voltage pulses at input of each converter within carrier half-cycle; length of first and central voltage pulses is found for each half-cycle at input of each converter, and phase shift of each converter is formed so that first converter runs at zero phase shift of input current, and next (even-numbered) converter runs with positive phase shift of input current relative to first converter; next (odd-numbered) converter runs with negative phase shift of input current relative to first converter. Each next odd-numbered converter runs with positive phase shift of input current relative to preceding odd-numbered converter; each next even-numbered converter runs with negative phase shift of input current relative to preceding even-numbered converter. Phase shift is found from formula where t₁ is phase length of first modulating-signal pulse within half-cycle; t_s is phase length of modulating-signal central pulse within half-cycle; ω is cyclic frequency; ε is number of modulating-voltage pulses at input of four-quadrant converter within half-cycle of input voltage; N is number of parallel-running converters.

EFFECT: improved characteristics of input current of consist.

1 cl, 3 dwg