Three-phase inverter arrangement

Claim 2

An inverter arrangement for generating a three-phase AC output voltage of the type having three single-phase inverters, each single-phase inverter being connected at an input to a DC voltage source, and at an output to a transformer arrangement by at least one low-pass filter, the arrangement further comprising: first, second, and third single-phase transformers in the transformer arrangement, each of said single-phase transformers having a converter-side winding connected to the low-pass filter, and a network-side winding, said network-side windings of said first, second, and third single-phase transformers being connected to one another in a Y-circuit configuration having a neutral terminal, said neutral terminal being connected to a reference potential; first, second, and third phase control means for controlling respective ones of the single-phase inverters, each of said first, second, and third phase control means having a vector-oriented control device coupled to an associated pulse control unit, said pulse control unit having at least one output for providing control pulses; vector oscillator means for generating a plurality of reference signals corresponding to a symmetrical three-phase system of reference vectors; and first and second input means in each of said vector-oriented control devices, said first input means being adapted to receive a corresponding one of said reference signals of said vector oscillator means, and said second input means being adapted for receiving a measurement signal corresponding in phase to a predetermined one of the three-phase AC output voltages.

Claim 3

The inverter arrangement of claim 1 wherein there is further provided: vector identifier means for determining angle components of a vector in said measurement signal; vector rotator means for generating a series voltage control signal and a shunt voltage control signal in response to said angle components determined by said vector indentifier and a corresponding one of said reference signals from said vector oscillator means; and vector analyzer means for generating an amplitude control signal and a phase control signal in response to said series voltage control signal and said shunt voltage control signal.

Claim 4

The inverter arrangement of claim 1 wherein said vector-oriented control device is further provided with: vector identifier means for determining angle components of a vector in said measurement signal; vector rotator means for generating DC voltage variables in the form of Cartesian coordinates in response to angle components determined by said vector identifier means and a corresponding one of said reference signals of said vector oscillator means; and vector analyzer means for converting said voltage variables from said Cartesian coordinates into polar coordinates so as to produce an amplitude control signal and a phase control signal.

Claim 5

An inverter arrangement for generating a three-phase AC output voltage of the type having first, second and third single-phase inverters, each single-phase inverter being connected at an input to a DC voltage source, and at an output to a transformer arrangement, the arrangement further comprising: first, second, and third single-phase transformers in the transformer arrangement, and first, second and third low-pass filters, corresponding to the single-phase inverters, each of said single-phase transformers having a converter-side winding connected to the output of the corresponding single-phase inverter, and a network-side winding, said network-side windings of said first, second, and third single-phase transformers being connected to one another in a Y-circuit configuration having a neutral terminal, said neutral terminal being connected to a reference potential; and said first, second and third low-pass filters being arranged on the converter-side winding of said corresponding transformers; first, second, and third phase control means for controlling respective ones of the single-phase inverters, each of said first, second, and third phase control means having a vector-oriented control device coupled to an associated pulse control unit, said pulse control unit having at least one output for providing control pulses; vector oscillator means for generating a plurality of reference signals corresponding to a symmetrical three-phase system of reference vectors; and first and second input means in each of said vector-oriented control devices, said first input means being adapted to receive a corresponding one of said reference signals of said vector oscillator means, and said second input means being adapted for receiving a measurement signal corresponding in phase to a pre-determined one of the three-phase AC output voltages.

Claim 6

An inverter arrangement for generating a three-phase AC output voltage of the type having first, second and third single-phase inverters, each single-phase inverter being connected at an input to a DC voltage source, and at an output to a transformer arrangement, the arrangement further comprising: first, second, and third single-phase transformers in the transformer arrangement, and first, second and third low-pass filters, corresponding to the single-phase inverters, each of said single-phase transformers having a converter-side winding connected to the output of the corresponding single-phase inverter, and a network-side winding, said network-side windings of said first, second, and third single-phase transformers being connected to one another in a Y-circuit configuration having a neutral terminal, said neutral terminal being connected to a reference potential; and said first, second and third low-pass filters being arranged on the converter-side winding of said corresponding transformers; first, second, and third phase control means for controlling respective ones of the single-phase inverters, each of said first, second, and third phase control means having a vector-oriented control device coupled to an associated pulse control unit, said pulse control unit having at least one output for providing control pulses; vector oscillator means for generating a plurality of reference signals corresponding to a symmetrical three-phase system of reference vectors; and first and second input means in each of said vector-oriented control devices, said first input means being adapted to receive a corresponding one of said reference signals of said vector oscillator means, and said second input means being adapted for receiving a measurement signal corresponding in phase to a pre-determined one of the three-phase AC output voltages.