| 摘要 |
A hybrid active power filter having programmed impedance characteristics is presented. In accordance with which, a passive device comprising a capacitor CF is connected in series with an active device which are together connected in shunt with a power source and a load at transmission lines of a power system. Capacitor CF substantially supports the full-line voltage VH of the power source, whereby the active filter is exposed to a substantially lower voltage than the line voltage VH. The active device includes on active filter, i.e., an inverter current regulator with a programmable controller for executing a control algorithm. The controller of the active device receives signals corresponding to a voltage VM, at the low side of filter capacitor CF. Voltage VM is at a substantially lower voltage than the line voltage VH, whereby the cost of sensing voltage VM is significantly less than sensing the high line voltage V. The control algorithm of the present invention is expressed as where IA is the current in the active device and YFAo is an order transfer function of the effective admittance of the active device. YFAo is a continuous function which is defined to provide a low impedance path at desired frequencies. Accordingly, the control algorithm controls the current IA in response to voltage VM sensed at the low side of filter capacitor CF as dictated by the programmed function. The active device may be connected to the passive filter at a junction between two capacitors or at a junction between two inductors.
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