HIGH-FREQUENCY CURRENT REDUCTION DEVICE
First Claim
1. A high-frequency current reduction device which comprises a noise reduction unit interposed between a first electric device and a second electric device by way of a single connection line between the first electric device and the second electric device, for reducing a high-frequency noise current flowing through the connection line from the first electric device,said noise reduction unit comprising:
- a detection unit that detects a noise current flowing through the connection line as a voltage;
a filter device that extracts a desired high-frequency component from the detected voltage by the detection unit;
a voltage amplifier that amplifies an output from the filter device; and
a current injection portion that includes a capacitor whose first terminal is connected to an injection point that is placed on the connection line and nearer to the second electric device than to the detection unit between the first electric device and the second electric device, and that injects a high-frequency current to the connection line;
wherein the detection unit is configured with a detection transformer that includes a conductive line serially connected to the connection line and a winding for current detection, andthe current injection portion applies to a second terminal of the capacitor, an output voltage from the voltage amplifier to thereby inject the high-frequency current in almost the same direction as the noise current into the connection line.
1 Assignment
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Accused Products
Abstract
In a system line for supplying power from an AC power source to a load through a converter and an inverter, a noise reduction unit is connected to a single connection line between the AC power source and the converter. In the noise reduction unit, a current transformer detects a noise current flowing through the connection line after converting it to a voltage, and the detected voltage V1 is supplied through a filter device to a voltage amplifier followed by being voltage-amplified and applied to a capacitor. The capacitor is connected to an injection point on the connection line, so that a high-frequency current in the same direction as the noise current is supplied to the converter from the connection line, to thereby reduce a high-frequency noise current at the AC power source side.
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Citations
16 Claims
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1. A high-frequency current reduction device which comprises a noise reduction unit interposed between a first electric device and a second electric device by way of a single connection line between the first electric device and the second electric device, for reducing a high-frequency noise current flowing through the connection line from the first electric device,
said noise reduction unit comprising: -
a detection unit that detects a noise current flowing through the connection line as a voltage; a filter device that extracts a desired high-frequency component from the detected voltage by the detection unit; a voltage amplifier that amplifies an output from the filter device; and a current injection portion that includes a capacitor whose first terminal is connected to an injection point that is placed on the connection line and nearer to the second electric device than to the detection unit between the first electric device and the second electric device, and that injects a high-frequency current to the connection line; wherein the detection unit is configured with a detection transformer that includes a conductive line serially connected to the connection line and a winding for current detection, and the current injection portion applies to a second terminal of the capacitor, an output voltage from the voltage amplifier to thereby inject the high-frequency current in almost the same direction as the noise current into the connection line. - View Dependent Claims (2, 3, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16)
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4. (canceled)
Specification