Method and apparatus for operating an inverter consisting of two sub-inverters
AssigneeSiemens Aktiengesellschaft
InventorKonrad Heintze
Life of this patent
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Abstract
An improved method and apparatus for operating an inverter comprising two sub-inverters having their outputs connected with each other through a choke with a center tap in which the outputs are controlled such that two AC output voltages displaced in phase with respect to each other are applied to the choke. According to the present invention in order to minimize the voltage-time area at the choke, the two AC voltages are reversed in polarity within the range of the control angle at least once with reversals in the two voltages always taking place at the same time and in opposite directions.
Claims17
A method of operating an inverter comprising two sub-inverters whose inputs are connected to a DC voltage source and whose outputs are connected together through a choke having a center tap where the AC output voltages of the sub-inverters shifted relative to each other by an adjustable control angle are combined through the choke to form a resultant voltage which is available at the center tap, comprising the steps of:
- a. reversing the two AC output voltages within a reversal portion defined as the range of the control angle during which the two voltages have opposite polarity;
- and
- b. carrying out said reversal at least once at each reversal portion in such a manner that both voltage are reversed simultaneously and in opposite directions.
In an inverter consisting of two sub-inverters whose inputs are connected to a DC voltage and whose outputs are connected with each other through a choke having a center tap such that the AC output voltages of the sub-inverters shifted relative to each other by an adjustable control angle are combined using the choke to form a resultant voltage at the center tap, apparatus for reversing, within the range of the control angle, the two AC output voltages at least once and simultaneously in opposite directions comprising:
- a. a frequency generator furnishing first and second modified triangular voltages having the same frequency and amplitude but phase shifted relative to each other by one-half their period;
- b. first and second comparator means each made up of a plurality of comparators having as first inputs said two modified triangular voltages respectively;
- c. means for providing as further inputs to both said first and second comparator means a plurality of voltages, the difference in voltages between each two voltages being equal, said means comprising a voltage divider provided with a common control voltage used for determining the control angle;
- d. first and second modulation means having the outputs of said respective first and second comparator means as inputs and providing outputs to control the sub-inverters in the range of the control angle such that a reversal takes place each time a comparator in one of said comparator means switches over.
Dependencies are inferred from the claim text.