US3825813A — Multi-phase thyristor inverter circuit

Claim 1

Independent Claim 261 words

Multi-phase thyristor inverter circuit to supply multi-phase a-c output at output terminals (R, S. T) from a d-c supply (11, 12) comprising a first group of thyristors (50, 60, 70); a second group of thyristors (53, 63, 73), each group having one thyristor terminal connected to a respective terminal of the d-c supply and the other terminals, each, being connected to the phase output terminals (R, S. T) of the inverter circuit; common quenching circuits (A, A'') for all the thyristors of a group; a positive return feed line (101); a negative return feed line (102); a diode (103, 104), each, connecting the respective positive return feed line (101) to the positive terminal (11) of the d-c supply and, respectively, the negative return feed line (102) to the negative terminal (12) of the d-c supply; a first group of return feed thyristors (56, 66, 76); a second groUp of return feed thyristors (55, 65, 75); the return feed thyristors of each group being connected between the ouput phase terminals (R, S, T) and the positive, and negative return feed lines respectively; and a set of two serially connected inductances (58a, 58b; 68a, 68b; 78a, 78b), the junction between the serially connected inductances being connected to the phase output terminals (R, S, T); one of the serially connected inductances, each, of the set being connected to the cathodes of the first group of thyristors (50, 60, 70), and the other terminal of the other inductance (58b, 68b, 78b) being connected to the anodes of the second group of thyristors (53, 63, 73).

Claim 2

Dependent Claim 261 words

Multi-phase thyristor inverter circuit to supply multi-phase a-c output at output terminals (R, S. T) from a d-c supply (11, 12) comprising a first group of thyristors (50, 60, 70); a second group of thyristors (53, 63, 73), each group having one thyristor terminal connected to a respective terminal of the d-c supply and the other terminals, each, being connected to the phase output terminals (R, S. T) of the inverter circuit; common quenching circuits (A, A'') for all the thyristors of a group; a positive return feed line (101); a negative return feed line (102); a diode (103, 104), each, connecting the respective positive return feed line (101) to the positive terminal (11) of the d-c supply and, respectively, the negative return feed line (102) to the negative terminal (12) of the d-c supply; a first group of return feed thyristors (56, 66, 76); a second groUp of return feed thyristors (55, 65, 75); the return feed thyristors of each group being connected between the ouput phase terminals (R, S, T) and the positive, and negative return feed lines respectively; and a set of two serially connected inductances (58a, 58b; 68a, 68b; 78a, 78b), the junction between the serially connected inductances being connected to the phase output terminals (R, S, T); one of the serially connected inductances, each, of the set being connected to the cathodes of the first group of thyristors (50, 60, 70), and the other terminal of the other inductance (58b, 68b, 78b) being connected to the anodes of the second group of thyristors (53, 63, 73).

Claim 3

Dependent Claim 60 words

Inverter circuit according to claim 1 wherein the inductances (58a, 68a, 78a) connected to the cathodes of the first group of thyristors (50, 60, 70) are wound on a common core (103a); and the inductances (58b, 68b, 78b) connected to the anodes of the thyristors of the second group (53, 63, 73) are wound on a common iron core (103b).

Claim 4

Dependent Claim 18 words

Inverter circuit according to claim 2 wherein the common cores (103a, 103b) are the legs of a U-core.

Claim 5

Dependent Claim 107 words

Inverter circuit according to claim 1 wherein the quenching circuits (A, A'') comprise a first quenching bridge including four quenching thyristors (30, 31, 32, 33) and a commutating capacitor (34) connected across the bridge, the other diagonal of the bridge being connected between the positive d-c supply terminal (11) and the negative return feed line (102); and a second quenching bridge including four further quenching thyristors (40, 41, 42, 43) and a commutating capacitor (44) connected across a diagonal of the bridge, the other diagonal of the second bridge being connected between the negative terminal (12) of the d-c supply and the positive return feed line (101).

Claim 6

Dependent Claim 109 words

Inverter circuit according to claim 1 wherein the quenching circuits comprise a first quenching circuit for the first group of thyristors connected between the positive terminal of the d-c supply (11) and the negative return feed line (102), and a second group of quenching circuits (A'') connected between the negative terminal of the d-c supply (12) and the positive return feed line (101); and said quenching circuits include energy storage means storing energy with a polarity counter the polarity of conduction of the thyristors which are to be quenched, and trigger means to discharge the energy storage means and apply a counter potential to the thyristor to be quenched.

Claim 7

Dependent Claim 37 words

Inverter circuit according to claim 1 wherein two quenching circuits (A, A'') are provided, one each being connected between a respective terminal of the d-c supply (11, 12) and the oppositely poled return feed line (102, 101).

Claim 8

Dependent Claim 43 words

Inverter circuit according to claim 6 further comprising a series circuit of a diode (110), two inductance means (107, 108) and a second diode (111) connected between the positive and negative return feed lines (101, 102) said diodes being poled in blocking direction.

Claim 9

Dependent Claim 57 words

Inverter circuit according to claim 7 further comprising two capacitors (105, 106) connected, in series, between the positive and negative terminals of the d-c supply, (11, 12), the common junction of said capacitors forming an artificial center for the battery supply; and means connecting the junction of said two serially connected inductance means to said artificial center.

Claim 10

Dependent Claim 43 words

Inverter circuit according to claim 7 wherein the d-c supply is a three terminal supply having a center connection between the positive and negative terminal; and wherein the junction (104) between said two inductance means (107, 108) is connected to said center terminal.

Claim 11

Dependent Claim 18 words

Inverter circuit according to claim 7 wherein said inductance means (107, 108) are wound on a common core.

Claim 12

Dependent Claim 43 words

Inverter circuit according to claim 1 in combination with an asynchronouS dynamo electric machine, the phase terminals of the armature windings (80, 81, 82) of the dynamo electric machine being connected to the phase output terminals (R, S, T) of said inverter circuit.

Claim 13

Dependent Claim 42 words

Inverter circuit and dynamo electric machine combination as claimed in claim 11, wherein the inverter circuit converts d-c to three-phase a-c, and the dynamo electric machine is a three-phase asynchronous motor capable of operating in motor, or dynamic braking, or generation mode.

Annuity Stage	Window Opens	Payment Deadline	Surcharge Period Until	Estimated Fee	Status
3.5 Years (Year 4)	1977-07-22	1978-01-21	1978-07-23	$2000.00	Window Closed / Lapsed
7.5 Years (Year 8)	1981-07-22	1982-01-21	1982-07-23	$3760.00	Window Closed / Lapsed
11.5 Years (Year 12)	1985-07-22	1986-01-21	1986-07-23	$7700.00	Window Closed / Lapsed

Multi-phase thyristor inverter circuit

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