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US 4,308,578 AGranted
Inverter device
AssigneeMitsubishi Denki Kabushiki Kaisha
InventorsYoshimoto Tamura, Hidehiko Sugimoto
Life of this patent
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Abstract
An inverter device for converting DC to AC by using thyristors as switching elements comprises a commutation circuit for turn-off of the thyristors which is formed by a serial connection of an auxiliary power source, a gate control thyristor and a thyristor which is commonly used and connected to a thyristor used as the switching element which is turned off by applying a reverse voltage by turning on the gate control thyristor and the thyristor of the commutation circuit.
Claims7
An inverter device which comprises a first DC power source;
- a serial connection of thyristors connected in parallel in forward direction between the positive and negative terminals of said first DC power source;
- a load whose terminal are respectively connected to middle parts of said serial connection of thyristors;
- a controller for feeding signals in a predetermined order for predetermined periods to said thyristors of said serial connection of thyristors, so that the output of said serial connection of thyristors to said load approximates an AC power source;
- rectifier elements which are respectively connected between said first DC power source and middle terminals of said thyristors of said serial connection of thyristors to shunt induced electromotive force resulted by said load;
- a second DC power source which is controlled by said controller to output for a predetermined period by synchronizing to a signal for forming the AC power, when said signal is fed by said controller;
- a group of thyristors which are connected to both terminals of said second DC power source and which are controlled by said controller to connect in reverse polarity to thyristors which are switched from ON state to OFF state of the thyristors of said serial connection of thyristors;
- and
- a third DC power source which is connected in reverse polarity directly to one terminal of each thyristor of said group of thyristors.
5 more elements
Dependencies are inferred from the claim text.