MKS Instruments, Inc.
Power converter control apparatus and method for high stability and power factor improvement in the presence of high source impedances

Abstract:

A power conversion system includes a feedback controller circuit connected between the output of a boost converter and a duty cycle control input of the boost converter. The feedback controller circuit comprises: a first summing node which generates an error signal indicative of a difference between a voltage of the output of the boost converter and a reference voltage, a compensator circuit receiving the error signal and applying a gain to the error signal to generate an amplified error signal, and a scaling circuit for scaling the amplified error signal to generate a scaled signal, which is applied to a duty cycle control input of the boost converter to alter the duty cycle and/or pulse frequency of the boost converter. The feedback controller circuit provides a frequency-dependent impedance transformation looking into the boost converter from the source such that instability due to line impedance is reduced.