Hybrid active power filter with programmed impedance characteristics

Abstract

Abstract A hybrid active power filter having programmed impedance characteristics is presented. In accordance with which, a passive device comprising a capacitor C F 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 C F substantially supports the full-line voltage V H of the power source, whereby the active filter is exposed to a substantially lower voltage than the line voltage V H . 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 V M , at the low side of filter capacitor C F . Voltage V M is at a substantially lower voltage than the line voltage V H , whereby the cost of sensing voltage V M is significantly less than sensing the high line voltage V.sub.. The control algorithm of the present invention is expressed as ##EQU1## where I A is the current in the active device and Y FAo is an order transfer function of the effective admittance of the active device. Y FAo is a continuous function which is defined to provide a low impedance path at desired frequencies. Accordingly, the control algorithm controls the current I A in response to voltage V M sensed at the low side of filter capacitor C F 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.

Inventors

• 👤 Einar Larsen
• 👤 Robert Delmerico

Bibliographic Details