System for adjusting and commutating current in the windings of an AC machine from a constant-voltage DC supply

Claim 2

A circuit for commutating current in the windings of an nphase electrical machine, wherein said current is derived from a constant current supply having DC output terminals, said circuit comprising: a. a current chopper having one end connected to one of said DC supply output terminals for obtaining from said supply a DC current of an adjustable given value, b. an inductor having one end connected to the other one of said DC supply output terminals for smoothing the adjusted current obtained from said current chopper, c. a 2 n-arm thyristorized routing bridge having an input side and an output side with n center points, said n center points connected to the n-phase electrical machine, one side of said routing bridge connected to the other side of said current chopper, the other side of said routing bridge connected to the other side of said smoothing inductance, d. a 2 n-arm semiconductor bridge having an input side and an output side with n center points, said n center points connected to the n-phase electrical machine, e. turn-off circuit means connected between each side of said semiconductor bridge and a corresponding side of said routing bridge for turning off the routing thyristors of said routing bridge, f. switching circuit means connected between each side of said semiconductor bridge and a corresponding side of said routing bridge for progressively transferring current from the semiconductor bridge to the routing bridge, and g. discharge circuit means for discharging excess charge stored in the switching circuit means.

Claim 3

A circuit for commutating current in the windings of an n-phase electrical machine, wherein said current is derived from a constant current supply having DC output terminals, said circuit comprising: a. a current chopper having one end connected to one of said DC supply output terminals for obtaining from said supply a DC current of an adjustable given value, b. an inductor having one end connected to the other one of said DC supply output terminals for smoothing the adjusted current obtained from said current chopper, c. a 2 n-arm thyristorized routing bridge having an input side and an output side with n center points, said n center points connected to the n-phase electrical machine, one side of said routing bridge connected to the other side of said current chopper, the other side of said routing bridge connected to the other side of said smoothing inductance, d. a 2 n-arm semiconductor bridge having an input side and an output side with n center points, said n center points connected to the n-phase electrical machine, e. turn-off circuit means connected between each side of said semiconductor bridge and a corresponding side of said routing bridge for turning off the routing thyristors of said routing bridge, f. switching circuit means connected between each side of said semiconductor bridge and a corresponding side of said routing bridge for progressively transferring current from the semiconductor bridge to the routing bridge, and g. discharge circuit means for discharging excess charge stored in the switching circuit means.

Claim 4

A circuit for commutating current in the windings of an n-phase electrical machine, wherein said current is derived from a constant current supply having DC output terminals, said circuit comprising: a. a current chopper having one end connected to one of said DC supply output terminals for obtaining from said supply a DC current of an adjustable given value, b. an inductor having one end connected to the other one of said DC supply output terminals for smoothing the adjusted current obtained from said current chopper, c. a 2 n-arm thyristorized routing bridge having an input side and an output side with n center points, said n center points connected to the n-phase electrical machine, one side of said routing bridge connected to the other side of said current chopper, the other side of said routing bridge connected to the other side of said smoothing inductance, d. a 2 n-arm semiconductor bridge having an input side and an output side with n center points, said n center points connected to the n-phase electrical machine, e. turn-off circuit means connected between each side of said semiconductor bridge and a corresponding side of said routing bridge for turning off the routing thyristors of said routing bridge, f. switching circuit means connected between each side of said semiconductor bridge and a corresponding side of said routing bridge for progressively transferring current from the semiconductor bridge to the routing bridge, and g. discharge circuit means for discharging excess charge stored in the switching circuit means.

Claim 5

A circuit according to claim 1 wherein the semiconductors of the semiconductor bridge are thyristors.

Claim 6

A circuit according to claim 2 wherein the turn-off circuit means includes two turn-off circuits associated respectively with each side of said routing bridge and said semiconductor bridge and wherein each turn-off circuit comprises a capacitor in series with a thyristor, the capacitor being common to the two turn-off circuits.

Claim 7

A circuit according to claim 3 wherein the switching circuit means includes two switching circuits associated respectively with each side of said routing bridge and said semiconductor bridge and wherein each switching circuit comprises a capacitor in series with a diode.

Claim 8

A circuit according to claim 4 wherein the discharge circuit means includes two discharge circuits associated with each switching circuit, for returning stored energy to the electrical machine.

Claim 9

A circuit according to claim 5 wherein the capacitor of the switching circuit associated with the side of the routing bridge connected to the current chopper returns its stored energy to the electrical machine via a thyristor; and wherein the capacitor of the switching circuit associates with the side of the routing bridge connected to the smoothing inductor is connected in series between said smoothing inductor and another inductor, said Capacitor returning its stored energy to the electrical machine via the smoothing inductor and said other inductor.

Claim 10

A system according to claim 3, comprising a single switching circuit for both sides of the routing bridge and the semiconductor bridge, said single switching circuit comprising a capacitor connected across a diode bridge, said diode bridge being connected in parallel across the turn-off capacitor.

Claim 11

A circuit according to claim 7 wherein the capacitor of the switching circuit restores its stored energy to the electrical machine via one of two circuits, each of said circuits comprising at least one thyristor on either side of the capacitor, one of said circuits enabling the machine to operate as a motor, the other of said circuits enabling the machine to operate as a generator.

Claim 12

A circuit according to claim 1 wherein the semiconductors of the semiconductor bridge are diodes.

Claim 13

A circuit according to claim 9 wherein the turn-off circuit means includes two turn-off circuits associated respectively with each side of said routing bridge circuit, and wherein each turn-off circuit comprises a capacitor in series between two thyristors, the capacitor being common to the two turn-off circuits.

Claim 14

A circuit according to claim 10 wherein the switching circuit means includes two switching circuits associated respectively with each side of said routing bridge and said semiconductor bridge and wherein each switching circuit comprises a capacitor in series with a diode.

Claim 15

A circuit according to claim 11 wherein the discharge circuit means includes two discharge circuits associated with each switching circuit, for returning stored energy to the electrical machine.