Patent ID: 9634580
Date: 2017-04-25
CPC Classifications: G01R,H02M,H02P

Claim:
1. A power converter controller for controlling a power converter every predetermined cycle, said power converter applying three-phase voltage to an inductive load to supply three-phase current to said inductive load, said power converter including three current paths each having a node and a pair of switches connected in series via said node between a pair of DC buses, said three-phase current being output from said three nodes according to conducting/non-conducting states of said three pairs of switches, said conducting/non-conducting states being based on a plurality of switching patterns, voltage vectors corresponding to said switching patterns being classified into a pair of zero voltage vectors and six non-zero voltage vectors other than said zero voltage vectors, a first one of said zero voltage vectors corresponding to a switching pattern in which said inductive load is connected to only a first one of said DC buses, a second one of said zero voltage vectors corresponding to a switching pattern in which said inductive load is connected to only a second one of said DC buses, said non-zero voltage vectors being shown with said zero voltage vectors as initial points to be located every angle of π/3 in a complex plane, each two of said non-zero voltage vectors that are located to form an angle of 2π/3 in said complex plane corresponding to said switching patterns that are common in one of said current paths and different in the other two of said current paths, each two of said non-zero voltage vectors that are located to form an angle of π in said complex plane corresponding to said switching patterns that are different in said three current paths, said power converter controller comprising: a difference command generator that generates a difference command equivalent to a time integral of said three-phase voltage applied to said inductive load in one of said predetermined cycles in said complex plane; a vector command generator that generates a plurality of vector commands that are respectively time integrals of said voltage vectors and compose said difference command; a switching signal generator that generates switching signals for controlling said conducting/non-conducting states of said three pairs of switches on the basis of said vector commands; and a phase-current computing unit that detects current flowing through said DC buses to obtain an estimated value for said three-phase current on the basis of said current and said vector commands, wherein at least two of said vector commands that are time integrals of different ones of said non-zero voltage vectors have magnitudes greater than or equal to a predetermined value that corresponds to a minimum required amount of time to maintain said switching patterns in order for said phase-current computing unit to detect said current.