Overvoltage protection circuit
First Claim
Patent Images
1. An overvoltage protection circuit, comprising:
- a plurality of series connected thyristor means having an overvoltage protection function;
a plurality of impedance means, each being connected in parallel with one of said thyristor means, respectively; and
said plurality of impedance means including at least a first impedance means and at least a second impedance means, wherein said first impedance means comprising a first impedance circuit having a first impedance value and said second impedance means comprising a second impedance circuit.
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Accused Products
Abstract
An overvoltage protection circuit including a plurality of series connected thyristors having an overvoltage protection function and a plurality of impedance circuits. Each of the impedance circuits is connected in parallel with one of the thyristors, respectively. The impedance circuits include at least a first impedance circuit having a first impedance value and a second impedance circuit having a second impedance value which is different from the first impedance value.
25 Citations
13 Claims
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1. An overvoltage protection circuit, comprising:
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a plurality of series connected thyristor means having an overvoltage protection function; a plurality of impedance means, each being connected in parallel with one of said thyristor means, respectively; and said plurality of impedance means including at least a first impedance means and at least a second impedance means, wherein said first impedance means comprising a first impedance circuit having a first impedance value and said second impedance means comprising a second impedance circuit. - View Dependent Claims (2, 3, 4, 5)
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6. An overvoltage protection equipment for protecting an electric equipment from overvoltage, comprising;
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three overvoltage protection circuits connected between respective two phases of said electric equipment; each of said three overvoltage protection circuit, including a plurality of series connected thyristor means having an overvoltage protection function, and a plurality of impedance means, each being connected in parallel with one of said thyristor means, respectively, and said plurality of impedance means comprising at least a first impedance means and at least a second impedance means, wherein said first impedance means comprising a first impedance circuit having a first impedance value and said second impedance means comprising a second impedance circuit having a second impedance value, said first impedance value being different from said second impedance value; wherein the turn-on voltage of said overvoltage protection circuit is finely adjusted based upon the values of said plurality of impedance means. - View Dependent Claims (7)
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8. An overvoltage protection equipment for protecting a synchronous motor and a rectifier for supplying DC power to a field circuit of said synchronous motor from overvoltage, comprising:
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an overvoltage protection circuit connected between said synchronous motor and said rectifier; said overvoltage protection circuit including a plurality of series connected thyristor means having an overvoltage protection function, and a plurality of impedance means, each being connected in parallel with one of said thyristor means, respectively, and said plurality of impedance means comprising at least a first impedance means and at least a second impedance means, wherein said first impedance means comprising a first impedance circuit having a first impedance value and said second impedance means comprising a second impedance circuit having a second impedance value, said first impedance value being different from said second impedance value; wherein the turn-on voltage of said overvoltage protection circuit is finely adjusted based upon the values of said plurality of impedance means. - View Dependent Claims (9)
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10. A power converter, comprising:
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a plurality of bridge connected arm circuits; each of said arm circuits including a series circuit of a reactor and an overvoltage protection circuit; said overvoltage protection circuit including a plurality of series connected thyristor means having an overvoltage protection function, and a plurality of impedance means, each being connected in parallel with one of said thyristor means, respectively, and said plurality of impedance means comprising at least a first impedance means and at least a second impedance means, wherein said first impedance means comprising a first impedance circuit having a first impedance value and said second impedance means comprising a second impedance circuit having a second impedance value, said first impedance value being different from said second impedance value; wherein the turn-on voltage of said overvoltage protection circuit is finely adjusted based upon the values of said plurality of impedance means. - View Dependent Claims (11)
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12. A static var compensator, comprising:
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delta connected three arm circuits connected between respective two phases of a power system; each of said arm circuits including a series circuit of a reactor and an overvoltage protection circuit; said overvoltage protection circuit including a plurality of series connected thyristor means having an overvoltage protection function, and a plurality of impedance means, each being connected in parallel with one of said thyristor means, respectively, and said plurality of impedance means comprising at least a first impedance means and at least a second impedance means, wherein said first impedance means comprising a first impedance circuit having a first impedance value and said second impedance means comprising a second impedance circuit having a second impedance value, said first impedance value being different from said second impedance value;
wherein the turn-on voltage of said overvoltage protection circuit is finely adjusted based upon the values of said plurality of impedance means. - View Dependent Claims (13)
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Specification