Power conversion device
First Claim
1. A power conversion device comprising:
- a direct-current main circuit that converts direct-current power into alternating-current power; and
a control unit that controls the direct-current main circuit, whereinthe direct-current main circuit includesa capacitor that constitutes the direct-current main circuit, a detector that detects a voltage of the capacitor, and a first discharge circuit that includes the capacitor and a first resistor, and that discharges electric charge accumulated in the capacitor via the first resistor, andthe control unit includes a detection circuit that compares a transition of a voltage estimated based on an initial voltage detected by the detector at a time of disconnecting the direct-current main circuit from a power supply and on a time constant of the first discharge circuit with a transition of a voltage detected by the detector, and that generates a detection signal indicating a sign that a short circuit fault occurs in the capacitor, and the control unit disconnects the direct-current main circuit from the power supply when the direct-current main circuit is not disconnected from the power supply for a predetermined period of time.
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Accused Products
Abstract
A power conversion device includes a main circuit unit (direct-current main circuit) that converts direct-current power into alternating-current power, and a control unit that controls the direct-current main circuit. The direct-current main circuit includes a voltage detector (detector) that detects a capacitor voltage and a discharge circuit that discharges energy accumulated in a capacitor. The control unit includes a detection circuit that estimates a capacitor voltage during a normal operation based on a voltage transmitted from the voltage detector in a state where the main circuit unit is disconnected from a power supply and that detects a sign that a short circuit fault occurs in the capacitor, and a control circuit that outputs a control signal for controlling the discharge circuit to operate when the control circuit receives a detection signal from the detection circuit.
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Citations
10 Claims
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1. A power conversion device comprising:
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a direct-current main circuit that converts direct-current power into alternating-current power; and a control unit that controls the direct-current main circuit, wherein the direct-current main circuit includes a capacitor that constitutes the direct-current main circuit, a detector that detects a voltage of the capacitor, and a first discharge circuit that includes the capacitor and a first resistor, and that discharges electric charge accumulated in the capacitor via the first resistor, and the control unit includes a detection circuit that compares a transition of a voltage estimated based on an initial voltage detected by the detector at a time of disconnecting the direct-current main circuit from a power supply and on a time constant of the first discharge circuit with a transition of a voltage detected by the detector, and that generates a detection signal indicating a sign that a short circuit fault occurs in the capacitor, and the control unit disconnects the direct-current main circuit from the power supply when the direct-current main circuit is not disconnected from the power supply for a predetermined period of time. - View Dependent Claims (2, 6, 7, 8)
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3. A power conversion device comprising:
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a direct-current main circuit that converts direct-current power into alternating-current power; and a control unit that controls the direct-current main circuit, wherein the direct-current main circuit includes a capacitor that constitutes the direct-current main circuit, a detector that detects a voltage of the capacitor, and a first discharge circuit that includes the capacitor and a first resistor, and that discharges electric charge accumulated in the capacitor via the first resistor, and the control unit includes a detection circuit that generates a detection signal indicating a sign that a short circuit fault occurs in the capacitor based on a gradient of an instant decrease for a period of time since the voltage detected by the detector at a time of disconnecting the direct-current main circuit from a power supply drops from a steady state until the voltage detected by the detector rises again to be closer to the steady state. - View Dependent Claims (4, 5, 9, 10)
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Specification