Abstract: The method: determines, within the switching cycle, when current is not provided to the DC-bus capacitor, determines, for each switching cycle, the sector of a reference vector, active vectors durations and null voltage vectors durations, determines from the determined durations, sampling instants, samples the currents through the three phases and the DC-bus voltage at the determined sampling instants, determines, from the phase currents sampled at the determined sampling instants, the current flowing through the DC-bus capacitor during the active vectors, estimates the capacitance value and/or the equivalent series resistance value of the DC-bus capacitor, compares the capacitance value and/or the equivalent series resistance value to a threshold and determines if the DC-bus capacitor reaches its end of life according to the comparison result.

Abstract: The method: determines, within the switching cycle, when current is not provided to the DC-bus capacitor, determines, for each switching cycle, the sector of a reference vector, active vectors durations and null voltage vectors durations, determines from the determined durations, sampling instants, samples the currents through the three phases and the DC-bus voltage at the determined sampling instants, determines, from the phase currents sampled at the determined sampling instants, the current flowing through the DC-bus capacitor during the active vectors, estimates the capacitance value and/or the equivalent series resistance value of the DC-bus capacitor, compares the capacitance value and/or the equivalent series resistance value to a threshold and determines if the DC-bus capacitor reaches its end of life according to the comparison result.

Abstract: A method for on-line monitoring an electrolytic capacitor condition comprising: measuring a voltage ripple across the electrolytic capacitor and the current ripple flowing through the electrolytic capacitor; measuring the temperature of the electrolytic capacitor; emulating the monitored electrolytic capacitor using a capacitor model comprising a capacitor and a solid state adjustable resistor, applying one of the measured ripple to the capacitor model, adjusting the solid state adjustable resistor to minimize the error between an estimated ripple provided by the capacitor model and the other measured ripple not applied to the capacitor model, and estimating an equivalent series resistance of the monitored electrolytic capacitor using value of the solid state adjustable resistor.

Abstract: A method for on-line monitoring an electrolytic capacitor condition comprising: measuring a voltage ripple across the electrolytic capacitor and the current ripple flowing through the electrolytic capacitor; measuring the temperature of the electrolytic capacitor; emulating the monitored electrolytic capacitor using a capacitor model comprising a capacitor and a solid state adjustable resistor, applying one of the measured ripple to the capacitor model, adjusting the solid state adjustable resistor to minimize the error between an estimated ripple provided by the capacitor model and the other measured ripple not applied to the capacitor model, and estimating an equivalent series resistance of the monitored electrolytic capacitor using value of the solid state adjustable resistor.

Abstract: The present invention concerns a method for discharging the capacitors of a boost converter composed of a number n of bridge devices connected in series, the boost converter is connected to electric direct current providing means, each bridge device is composed of plural switches and a capacitor. The method comprises the steps of setting the switches of the bridge devices in n?1 different configurations in order to discharge the capacitors of n?1 different bridge devices within n?1 consecutive periods of time.