| 摘要 |
The subject of the invention is a method for monitoring DC link capacitance in power converters which is useful in condition monitoring of electronic equipment. The inventive method comprises the following steps:
measuring current of the phase a, b, c and voltage of the DC link; determining inverter switch states of the inverter and rectifier switch states of the rectifier for each phase a, b, c; generating a trigger signal when the value of the inverter switch states of the inverter for each phase a, b, c have an equal values and determining a triggered time duration for the trigger signal;
determining the rectifier switch states of the rectifier for each phase a, b, c at the triggered time duration and calculation current of the phase a, b, c and voltage of the DC link at the triggered time duration; reconstructing the DC link current at the triggered time duration; calculating an indicator ERS (Equivalent Series Resistance) for the DC link voltage at the triggered time duration; calculating a total DC link capacitance C and comparing it with the initial DC link capacitance. When the initial DC link capacitance is bigger than a threshold value given by user then and triggering an alarm. |
