Thyristor power converter with switched impedance
AssigneeMitsubishi Denki Kabushiki Kaisha
InventorToshiaki Ishii
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Abstract
An ac to dc power conversion apparatus employing commutated thyristors has a series circuit comprising a capacitor 8 and an impedance element 9 connected at the input side of a thyristor conversion unit 4. The capacitor reduces notch voltages generated during the commutation of the thyristors, and the impedance element prevents the capacitor from resonating with other inductive reactances in the circuit. A switching device 10 is connected in parallel with the impedance element, and is closed during the commutation of the thyristors to maximize the notch voltage reduction.
Claims6
A thyristor power conversion apparatus for converting ac power to dc power by thyristor commutation, comprising:
- (a) an ac power supply (1) having an internal reactance (2),
- (b) thyristor means (4) for converting ac power to dc power, and having a reactance component (3) on an input side thereof,
- (c) capacitor means (8) connected to said input side of said thyristor means,
- (d) impedance element means (9) connected in series with said capacitor means,
- (e) switching means (10) connected in parallel with said impedance means, and
- (f) firing circuit means (11) for generating;
- (1) firing signals to commutate said thyristor means, and
- (2) switching signals to close said switching means only during the commutation of said thyristor means.
Dependencies are inferred from the claim text.