Active harmonic suppression equipment and control method therefor
First Claim
1. An active harmonic suppression equipment comprising:
- a serially connected capacitor/inductor set consisting of a reactive power compensation ac capacitor and a filter inductor;
while an impedance thereof is in fundamental frequency, the serially connected capacitor/inductor set performs as a capacitor and has fundamental reactive compensating function;
while the impedance thereof is in high frequency, the serially connected capacitor/inductor set performs as an inductor and has filtering function used to filter high frequency switching harmonic current;
the serially connected capacitor/inductor set electrically connected to a power feeder;
a C-R-C filter set connected to the power feeder and used to filter high frequency switching harmonic current;
a dc capacitor bank performing as an energy storage element and providing a dc voltage;
a power converter converting the dc voltage into a compensating voltage which is flowing through the serially connected capacitor/inductor set, and the C-R-C filter set to produce a compensating current which is injected into the power feeder to suppress harmonic currents generated by nonlinear loads, thereby adjusting a utility current to be approximated as a sine-wave; and
a control circuit detecting the load current, the utility current, the output current of the power converter and the voltage of the dc capacitor to calculate a reference voltage of the power converter and signals which are used to drive the power converter.
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Accused Products
Abstract
An active harmonic suppression equipment is consisted of a dc capacitor, a power converter, a serially connected inductor/capacitor set, a C-R-C filter set and a control circuit. The dc capacitor operates as an energy storage device and supplies a dc voltage, and the power converter electrically connected thereto is used to convert the dc voltage into a compensating voltage. The inductor/capacitor set and the C-R-C filter set are commonly converting the compensating voltage into a compensating current injecting into a power feeder in order to suppress harmonic currents generated by nonlinear loads, thereby adjusting an utility current to be approximated as a sine-wave.
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Citations
10 Claims
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1. An active harmonic suppression equipment comprising:
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a serially connected capacitor/inductor set consisting of a reactive power compensation ac capacitor and a filter inductor;
while an impedance thereof is in fundamental frequency, the serially connected capacitor/inductor set performs as a capacitor and has fundamental reactive compensating function;
while the impedance thereof is in high frequency, the serially connected capacitor/inductor set performs as an inductor and has filtering function used to filter high frequency switching harmonic current;
the serially connected capacitor/inductor set electrically connected to a power feeder;
a C-R-C filter set connected to the power feeder and used to filter high frequency switching harmonic current;
a dc capacitor bank performing as an energy storage element and providing a dc voltage;
a power converter converting the dc voltage into a compensating voltage which is flowing through the serially connected capacitor/inductor set, and the C-R-C filter set to produce a compensating current which is injected into the power feeder to suppress harmonic currents generated by nonlinear loads, thereby adjusting a utility current to be approximated as a sine-wave; and
a control circuit detecting the load current, the utility current, the output current of the power converter and the voltage of the dc capacitor to calculate a reference voltage of the power converter and signals which are used to drive the power converter. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. An control method for an active harmonic suppression equipment comprising steps:
a control circuit retrieving a load current, an utility current, an output current of a power converter, and a voltage of a dc capacitor, and thereby calculating an expected voltage as well as a reference signal;
signals modulating from a pulse width modulator used to drive power switching devices of the power converter and convert an dc voltage produced from the dc capacitor into a compensating voltage which is successively passed through a serially connected capacitor/inductor set and a C-R-C filter set to produce a compensating current which is injected into a power feeder to filter harmonic currents generated by nonlinear loads, thereby adjusting the utility current to be approximated a sine-wave.
Specification