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US 4,060,757 AGranted
Inverters having a transformer-coupled commutating circuit
AssigneeGeneral Electric Company
InventorWilliam McMurray
Life of this patent
Estimating the term…
Abstract
In force-commutated single phase and polyphase thyristor inverters, a single commutating pulse generator produces commutating impulses for all the commutating thyristors which are individually transformer-coupled to the power circuit to turn off a selected load thyristor. Coasting thyristors to provide zero output voltage levels are also commutated without additional components. The basic commutating pulse generator has one capacitor with provision for recovering trapped energy, and pulse waveshaping and two-level overcurrent capability can be added economically.
Claims28
An inverter circuit comprising
- at least one half-bridge inverter unit including first and second main thyristors connected in series between a pair of input unidirectional voltage supply terminals for alternate conduction of current selectively through the primary winding means of coupling transformer means to provide alternating-current output voltage at an output terminal, and feedback rectifier means in parallel with each main thyristor,
- said coupling transformer means shaving inductively coupled secondary winding means and functioning as a spanning reactor and to couple commutating current pulses to said main thyristors that are produced by a single commutating pulse generator,
- said commutating pulse generator including a main commutating capacitor and at least one series-connected auxiliary thyristor for initiating discharge of said main commutating capacitor selectively through said secondary winding means, rebound circuit means comprising a rebound rectifier and rebound inductor in series across said main commutating capacitor to recover trapped energy, and a recharge thyristor effectively connected in series with said main commutating capacitor and rebound inductor between a pair of auxiliary supply input terminals for independently recharging said main commutating capacitor to an initial voltage with the same polarity which, upon transformation into the primary winding means, is high enough to assure return of excess commutating pulse energy to the input terminals, and
- control means for rendering said thyristors conductive in a prescribed sequence.
1 more element
An inverter circuit comprising
- at least one inverter unit having a pair of input unidirectional voltage terminals and including an output transformer having a center-tapped primary winding and an inductively coupled secondary winding with a pair of output terminals, first and second main thyristors respectively connected between one input terminal and either end of said output transformer primary winding for conduction alternately to provide alternating-current output voltage between said output terminals, a coupling transformer having a primary winding connected between the other input terminal and the center tap of said output transformer primary winding, and feedback rectifier means in parallel with each main thyristor,
- said coupling transformer having an inductively coupled secondary winding and functioning effectively as an input terminal spanning reactor and to couple commutating current pulses to said main thyristors that are produced by a single commutating pulse generator,
- said commutating pulse generator including a main commutating capacitor and a series-connected auxiliary thyristor for initiating discharge of said main commutating capacitor through said secondary winding, rebound circuit means comprising a rebound rectifier and rebound inductor in series across said main commutating capacitor to recover trapped energy, and a recharge thyristor effectively connected in series with said main commutating capacitor for independently recharging said main commutating capacitor to an initial voltage which, upon transformation into said primary winding, is higher than the input voltage with the same polarity, and
- control means for rendering said thyristors conductive in a prescribed sequence.
1 more element
An inverter circuit comprising
- a plurality of half-bridge inverter units respectively connected between a pair of input unidirectional voltage supply terminals,
- each half-bridge inverter unit including first and second main thyristors connected in series with the primary winding of a respective coupling transformer for alternate conduction to provide alternating-current output voltage at an output terminal coupled to the center tap of said primary winding, and feedback rectifier means in parallel with each main thyristor,
- the respective coupling transformers each having an inductively coupled secondary winding and functioning as an input terminal spanning reactor and to couple commutating current pulses to the corresponding main thyristors that are produced by a single commutating pulse generator,
- said commutating pulse generator including a main commutating capacitor and a plurality of auxiliary thyristors for individually coupling the respective secondary windings across said main commutating capacitor and initiating discharge thereof, rebound circuit means for recovering trapped energy, and recharge means for independently recharging said main commutating capacitor to an initial voltage which, upon transformation into the respective primary windings, is higher than the input voltage with the same polarity, and
- control means for rendering said thyristors conductive in a prescribed sequence.
2 more elements
An inverter circuit comprising
- a plurality of half-bridge inverter units respectively connected between a pair of input unidirectional voltage supply terminals,
- each half-bridge inverter unit including first and second main thyristors connected in series with the primary windings of a pair of coupling transformers for alternate conduction to provide alternating-current output voltage at an output terminal effectively coupled to the junction of said primary windings, and feedback rectifier means in parallel with each main thyristor,
- each pair of coupling transformers respectively having separate inductively coupled secondary windings and functioning as spanning reactors and to couple commutating current pulses selectively to the respective main thyristors that are produced by a single commutating pulse generator,
- said commutating pulse generator including a main commutating capacitor and a plurality of auxiliary thyristors for individually coupling all the secondary windings across said main commutating capacitor and initiating discharge thereof, rebound circuit means for recovering trapped energy, and recharge means for independently recharging said main commutating capacitor to an initial voltage which, upon transformation into the associated primary winding, is higher than one-half the input voltage and has the same polarity, and
- control means for rendering said thyristors conductive in a prescribed sequence.
2 more elements
Dependencies are inferred from the claim text.