Active filter for power distribution system with selectable harmonic elimination
First Claim
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1. A power distribution system comprising:
- an ac power source;
a power bus connected to the ac power source;
a capacitor bank shunt-connected to the power bus; and
an active filter shunt-connected to the power bus, the active filter including an inverter, an inverter control and current sensors, each current sensor sensing current flowing through a corresponding capacitor of the capacitor bank, the inverter control, in response to the current sensors, controlling the inverter to inject harmonic currents into the power bus.
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Abstract
A power distribution system includes an ac power source; a power bus connected to the ac power source; a capacitor bank shunt-connected to the power bus; and an active filter shunt-connected to the power bus. The active filter includes current sensors, an inverter and an inverter control. Each current sensor senses current flowing through a corresponding capacitor of the capacitor bank. The inverter control, in response to the current sensors, controls the inverter to inject harmonic currents into the power bus.
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Citations
27 Claims
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1. A power distribution system comprising:
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an ac power source;
a power bus connected to the ac power source;
a capacitor bank shunt-connected to the power bus; and
an active filter shunt-connected to the power bus, the active filter including an inverter, an inverter control and current sensors, each current sensor sensing current flowing through a corresponding capacitor of the capacitor bank, the inverter control, in response to the current sensors, controlling the inverter to inject harmonic currents into the power bus. - View Dependent Claims (2, 3, 4, 5, 14, 15, 16, 17)
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6. A power distribution system comprising:
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an ac power source;
a power bus connected to the ac power source;
a capacitor bank shunt-connected to the power bus;
an active filter shunt-connected to the power bus, wherein the active filter includes an inverter, an inverter control and current sensors, each current sensor sensing current flowing through a corresponding capacitor of the capacitor bank, the inverter control, in response to the current sensors controlling the inverter to inject harmonic currents into the power bus; and
wherein the active filter further includes a plurality of contol loops, each control loop causing the filter to inject a different harmonic current into the power bus, wherein each control loop generates a voltage command corresponding to a characteristic harmonic, and wherein the active filter further includes means for summing the voltage command with a command corresponding to inverter voltage, and vector modulation logic, responsive to an output of the summing means, for controlling the inverter. - View Dependent Claims (7, 8, 9, 10, 11, 12, 13)
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18. An active filter for a power distribution system, the system including a power bus, the filter comprising:
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an inverter;
means for generating a plurality of different voltage commands wherein the voltage commands are in response to a voltage of a capacitor bank, each voltage command corresponding to a different harmonic current;
means for summing the different voltage commands with a voltage command representing inverter voltage; and
means, responsive to the summing means, for controlling the inverter to function as a current controlled-current source that injects harmonic currents into the power bus such that the voltage on the power bus contains only a fundamental component.
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19. An active filter for a power distribution system, the system including a power bus and a capacitor bank shunt-connected to the power bus, the filter comprising:
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an inverter; and
a plurality of control loops, each control loop corresponding to a different multiple of capacitor bank Park Vector angle, each control loop causing the inverter to inject a different harmonic current into the power bus.
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20. An active filter for a power distribution system, the system including a power bus and a capacitor bank shunt-connected to the power bus, the filter comprising:
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an inverter;
a plurality of control loops, each control loop corresponding to a different multiple of capacitor bank Park Vector angle, each control loop causing the inverter to inject a different harmonic current into the power bus; and
an inverter overcurrent regulator for changing gain of the control loops in inverse proportion to an increase in overcurrent. - View Dependent Claims (21, 22, 23, 24, 25)
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26. A method of using an inverter to filter harmonic currents on a power bus of a power distribution system, a capacitor bank being shunt-connected across the power bus, the method comprising:
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measuring currents flowing through the capacitors of the capacitor bank; and
controlling the inverter to inject harmonic currents into the power bus in response to the measured currents so that the inverter supplies harmonic current demands of non linear loads on the power bus. - View Dependent Claims (27)
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Specification