NON-INTRUSIVE ESR/C ESTIMATION METHOD FOR DC BUS CAPACITOR AGEING DETECTION IN POWER CONVERTERS

摘要

A method of performing monitoring of parameters of a DC bus capacitor bank (2) composed of at least one capacitor in a power converter with a front-end (1), an output stage (3) and PWM control (7) of gates of switches of the output stage, said power converter having current sensing means (5, 6) on output phases of the output stage and a voltage sensing means (8) on the DC-bus, said voltage sensing means comprising a conditioning circuit (81) to extract and scale HF ripple of the DC-bus voltage, wherein said method comprises the steps of calculating a HF part of the phase current through current measurements sensed by said current sensor within selected transitions between switching states of the output stage and calculating a HF part of the DC-bus voltage through voltage measurements sensed by said voltage sensing means within selected switching states.