Electronically tuned matching network using predictor-corrector control system

摘要

The impedance of a generator (10) is matched with an unknown and variable impedance of a load (12) to maximize power transfer to the load by means of an adjustable impedance matching network (18). The magnitude of the reflection coefficient is determined from a measured electrical signal. A controller (34) computes a new optimum impedance adjustment to the impedance of the adjustable impedance device to reduce the magnitude of the reflection coefficient. The controller uses a control equation with parameters selected to ensure rapid convergence on the maximum-power condition, without overshoot or instability, where the magnitude of the reflection coefficient is used as a sealing factor for the impedance adjustment. The invention has application to power supplies for plasma processing in the fabrication of semiconductor circuitry.