Patent ID: 8867247

Claim:
A semiconductor power converter comprising: a power converter including arms constituting three-phase bridge connections having AC-side terminals which are connected with a three-phase AC system via an inductance, said arms having self-extinguishing semiconductor devices connected thereto, said self-extinguishing semiconductor devices being IGBTs or combinations of MOSFETs and free-wheeling diodes; a voltage-measuring device for measuring an AC voltage developed across the three-phase AC system; a current-measuring device for measuring an AC current flowing through the power converter; a phase detector for detecting phase θ of the AC voltage; an AC current adjuster for outputting commanded pulses to the power converter based on a commanded active current value I qref and a commanded reactive current value I dref along two axes and on an output from the AC current-measuring device; a two-phase voltage vector calculator for receiving a measured value of voltage developed across the three-phase AC system and calculating a positive-sequence voltage vector V p and a negative-sequence voltage vector V n ; and a phase calculator for calculating and outputting a positive-sequence voltage phase θ p from a reference phase θ for the two-phase voltage vector calculator and from the positive-sequence voltage vector V p ; wherein said AC current adjuster calculates a commanded positive-sequence current vector I pref from the commanded two-axis current values I qref and I dref , calculates a commanded negative-sequence current vector I nref using the relationship, I nref =−(V n /V p )×I pref , calculates commanded three-phase current vectors I aref , I bref , and I cref from the commanded positive-sequence current vector I pref and from the commanded negative-sequence current vector I nef , calculates commanded three-phase current values from the commanded three-phase current vectors and from the positive-sequence voltage phase θ p , and outputs commanded pulses to bring the commanded three-phase current values into agreement with the measured values of AC current.