Method and apparatus for detecting shortcircuit in arm of GTO inverter
AssigneeHitachi, Ltd.
InventorsYasuo Matsuda, Kazuo Honda, Takeo Maeda
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Abstract
Shortcircuit in an arm including a series connection of GTO's and reactors of an inverter is detected by sensing a voltage across the reactor. In one method, the shortcircuit in the arm is detected when voltages are coincidently applied to a P-line arm reactor and an N-line arm reactor for a predetermined time period. In another method, it is detected when an integrated value of a voltage across at least one of the reactors exceeds a predetermined level.
Claims6
A method for detecting a shortcircuit in an arm of a GTO inverter provided with at least one pair of arms, each arm being composed of a series connection of a single gate turn-off thyristor and a single reactor, said method comprising the steps of:
- sensing the voltage across each of said reactors of said paired arms;
- detecting if said sensed voltages across said reactors last coincidentally for longer than a predetermined time period;
- and
- determining the shortcircuit in one of said paired arms when said voltages last coincidentally for longer than said predetermined time period.
An apparatus for detecting a shortcircuit in an arm of a GTO inverter provided with at least one pair of arms, each arm being composed of a series connection of a single gate turn-off thyristor and a single reactor, said apparatus comprising:
- (i) first means connected across one of the reactors of said paired arms for sensing a voltage thereacross;
- (ii) second means connected across the other of said reactors for sensing a voltage thereacross;
- (iii) third means connected to said first and second means for ANDing the outputs thereof;
- and
- (iv) fourth means connected to the output of said third means for detecting if said third means produces an output for longer than a predetermined time period.
Dependencies are inferred from the claim text.