Method and apparatus for circuit monitoring

A non-transitory computer readable medium having instructions stored thereon, the instructions, when executed on at least one processor, cause the at least one processor to perform circuit monitoring operation, comprising:

• detecting a waveform of first voltage at a DC-link capacitor in a power converter, the first voltage being generated by turning on a chopper circuit coupling in parallel to the DC-link;
• determining a phase angle shift of the waveform of first voltage with respect to a waveform of second voltage at a rectifier in the power converter or a power supply for the power converter;
• determining magnitude of the waveform of first voltage;
• and
• determining, based on at least one of the magnitude and the phase angle shift, a parameter indicative of a health condition of the DC-link capacitor.

A computer program product being tangibly stored on a non-transitory computer readable storage medium and comprising instructions which, when executed on at least one processor, cause the at least one processor to perform circuit monitoring operation, comprising:

• detecting a waveform of first voltage at a DC-link capacitor in a power converter, the first voltage being generated by turning on a chopper circuit coupling in parallel to the DC-link;
• determining a phase angle shift of the waveform of first voltage with respect to a waveform of second voltage at a rectifier in the power converter or a power supply for the power converter;
• determining magnitude of the waveform of first voltage;
• and
• determining, based on at least one of the magnitude and the phase angle shift, a parameter indicative of a health condition of the DC-link capacitor.

An apparatus for circuit monitoring, comprising:

• a voltage detector configured to detect a waveform of first voltage at a DC-link capacitor in a power converter, the first voltage being generated by turning on a chopper circuit coupling in parallel to the DC-link;
• a voltage sensor configured to detect a waveform of second voltage at a rectifier;
• and
• a controller configured to:
• determine a phase angle shift of the waveform of first voltage with respect to the waveform of second voltage at the rectifier in the power converter or a power supply for the power converter;
• determine magnitude of the waveform of first voltage;
• and
• determine, based on at least one of the magnitude and the phase angle shift, a parameter indicative of a health condition of the DC-link capacitor.