Arrangement for injecting electric power into an AC network by means of an asynchronous machine, and method for operating the asynchronous machine

1. A configuration, comprising:

an asynchronous machine which, in generator operation, is configured to inject electric power into an AC network; and

a modular multi-stage converter, wherein said asynchronous machine is operated in a double-feed arrangement by said modular multi-stage converter in a matrix configuration, said multi-stage converter having a plurality of converter arms, each of said converter arms having a series-connected configuration of two-pole switching modules, each of said switching modules having interruptible power semiconductors and an energy store, each of said converter arms having a bridging switch and at least one charging resistor for being bridged by said bridging switch, said at least one charging resistor for pre-charging said energy store.

2. The configuration according to claim 1 , wherein said asynchronous machine has a rotor and said modular multi-stage converter is connected to said rotor of said asynchronous machine.

3. The configuration according to claim 1 , wherein said multi-stage converter has an n-phase first AC voltage terminal, which is connected to said asynchronous machine, and an m-phase second AC voltage terminal, which is connected to the AC network, wherein each of n phases of said first AC voltage terminal is connected to each of m phases of said second AC voltage terminal by means of exactly one of said converter arms.

4. The configuration according to claim 1 , wherein said interruptible power semiconductors and said energy store of said switching modules are respectively mutually connected in a full-bridge circuit.

5. The configuration according to claim 1 , further comprising a transformer, said modular multi-stage converter is connected to the AC network via said transformer.

6. The configuration according to claim 1 , further comprising a turbine of a conventional energy system, said asynchronous machine is connected, on an input side, to said turbine.

7. The configuration according to claim 6 , wherein said turbine is operated at a turbine frequency, wherein the turbine frequency and a frequency of the AC network are different.

8. The configuration according to claim 1 , further comprising a control apparatus, by means of said control apparatus reactive power on said asynchronous machine and in the AC network is controllable.

9. A method for operating an asynchronous machine, in a generator operation, for injecting electrical energy into an AC network, which comprises the steps of:

operating the asynchronous machine in a double-feed configuration, by an employment of a modular multi-stage converter in a matrix configuration having a plurality of converter arms, each of the converter arms having a series-connected configuration of two-pole switching modules, each of the switching modules having interruptible power semiconductors and an energy store, each of the converter arms having a bridging switch and at least one charging resistor for being bridged by the bridging switch; and

pre-charging the at least one charging resistor for the energy store.