Inverter provided with an overvoltage clamping circuit
First Claim
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1. An overvoltage suppressing apparatus, comprising:
- a voltage source inverter having switching transistors, recirculating diodes connected across current paths of the switching transistors, and an output terminal;
at least one reactor having an input terminal connected to the output terminal of said voltage source inverter and an output terminal to be connected to the primary side of a boosting transformer;
a clamping circuit including a diode for clamping an output voltage at the output terminal of said reactor to a first predetermined potential so that a potential on said output terminal of said reactor does not exceed said first predetermined potential; and
at least one capacitor having one end connected to the output terminal of said reactor and another end coupled to a second predetermined potential, said capacitor and said reactor forming a resonant circuit which limits changes in potential between said first and second predetermined potentials on said output terminal to a resonance curve defined by said resonant circuit.
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Abstract
Three-phase outputs of a voltage source inverter are supplied to AC input terminals of a diode bridge through reactors, respectively, and its DC outputs are clamped by a voltage of a first DC power source. The AC input terminals of the diode bridge are further connected to AC input terminals of a second diode bridge through capacitors, and its DC outputs are clamped by a second DC power source.
56 Citations
14 Claims
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1. An overvoltage suppressing apparatus, comprising:
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a voltage source inverter having switching transistors, recirculating diodes connected across current paths of the switching transistors, and an output terminal; at least one reactor having an input terminal connected to the output terminal of said voltage source inverter and an output terminal to be connected to the primary side of a boosting transformer; a clamping circuit including a diode for clamping an output voltage at the output terminal of said reactor to a first predetermined potential so that a potential on said output terminal of said reactor does not exceed said first predetermined potential; and at least one capacitor having one end connected to the output terminal of said reactor and another end coupled to a second predetermined potential, said capacitor and said reactor forming a resonant circuit which limits changes in potential between said first and second predetermined potentials on said output terminal to a resonance curve defined by said resonant circuit. - View Dependent Claims (2)
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3. An overvoltage suppressing apparatus, comprising:
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a DC power source; a three-phase voltage source inverter having DC power input terminals connected to the DC power source and having three output terminals; three reactors having input terminals connected to respective of the output terminals of the voltage source inverter and taps provided as output terminals for connection to the primary side of a boosting transformer; a clamping circuit including three diodes for clamping the three output terminals of said reactors to a first predetermined potential so that the respective potentials on said output terminals of said reactors do not exceed said first predetermined potential; and three capacitors each having one end connected to one of the output terminals of said reactors and another end coupled to a second predetermined potential, said capacitors and said reactors forming resonant circuits which limit changes in potential between said first and second predetermined potentials of said output terminals to a resonance curve defined by said resonant circuits. - View Dependent Claims (4, 5, 6, 7, 8, 9)
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10. An overvoltage suppressing apparatus, comprising:
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a first DC power source; a three-phase voltage source inverter having DC power input terminals connected to the first DC power source and having three output terminals; three reactors having input terminals connected to respective of the output terminals of the voltage source inverter and output terminals for connection to the primary side of a boosting transformer; a clamping circuit including three diodes for clamping the three output terminals of said reactors to a predetermined potential so that the respective potentials on said output terminals of said reactors do not exceed said predetermined potential; and three capacitors having one end connected to respective of the output terminals of said reactors and another end commonly interconnected to each other, said capacitors and said reactors forming resonant circuits which limit potential changes at the reactor output terminals to a resonance curve defined by said resonant circuits. - View Dependent Claims (11, 12, 13, 14)
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Specification