CHOKE WITH CURRENT SENSOR
First Claim
1. A motor drive system, comprising:
- converter circuitry configured to receive input three-phase alternating current (AC) power from an AC power source and convert the three-phase AC power into direct current (DC) power;
a DC bus configured to receive the DC power from the converter circuitry;
inverter circuitry configured to receive the DC power from the DC bus and convert it into controlled frequency output AC power for use by a three-phase motor; and
a common mode choke having a plurality of sets of primary windings and a set of secondary windings separate from the plurality of sets of primary windings, each set of primary windings directly connected to a phase of AC power, wherein the set of secondary windings are not directly connected to a phase of AC power, and wherein the set of secondary windings terminate with a burden resistor.
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Accused Products
Abstract
The present invention relates generally to systems and methods for detecting ground faults (i.e., line-to-ground faults) in motor drive systems. In particular, the embodiments described herein include a common mode choke of a motor drive system having additional (i.e., secondary) turns wound around a core of the common mode choke. These secondary turns are in addition to and separate from a plurality of sets of primary turns wound around the core of the common mode choke, each set of primary turns corresponding to a phase of AC power to which the common mode choke is directly coupled. The secondary turns terminate in series with a burden resistor. Ground faults may be detected by monitoring the voltage across the burden resistor. More specifically, the embodiments described herein include a controller including program instructions for receiving signals indicative of the voltage across the burden resistor, and for monitoring the voltage across the burden resistor to determine when ground faults occur in the motor drive system.
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Citations
20 Claims
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1. A motor drive system, comprising:
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converter circuitry configured to receive input three-phase alternating current (AC) power from an AC power source and convert the three-phase AC power into direct current (DC) power; a DC bus configured to receive the DC power from the converter circuitry; inverter circuitry configured to receive the DC power from the DC bus and convert it into controlled frequency output AC power for use by a three-phase motor; and a common mode choke having a plurality of sets of primary windings and a set of secondary windings separate from the plurality of sets of primary windings, each set of primary windings directly connected to a phase of AC power, wherein the set of secondary windings are not directly connected to a phase of AC power, and wherein the set of secondary windings terminate with a burden resistor. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A method, comprising:
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monitoring signals indicative of a voltage across a burden resistor in series with a set of secondary turns wound around a core of a common mode choke of a motor drive system; and determining whether a ground fault has occurred in the motor drive system based on changes in the voltage across the burden resistor over time. - View Dependent Claims (10, 11, 12, 13, 14, 15, 16)
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17. A common mode choke system, comprising:
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a plurality of sets of primary windings, wherein each set of primary windings is directly connected to a phase of alternating current (AC) power; and a set of secondary windings separate from the sets of primary windings, wherein the set of secondary windings are not directly connected to a phase of AC power, and wherein the set of secondary windings terminate with a burden resistor. - View Dependent Claims (18, 19, 20)
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Specification