{
  "$type": "site.standard.document",
  "description": "A method of estimating a quantity dependent on a capacitance (Cf) of an electrical filter (14) connected to an AC side (16) of an electrical converter (12) comprises: injecting a plurality of frequency components (42) into a voltage reference (34, 34') of the electrical converter (12), wherein the…",
  "path": "/patents/1393008",
  "publishedAt": "2024-12-11T00:00:00.000Z",
  "site": "at://did:plc:oql6ds5vnff4ugar6rruliwd/site.standard.publication/3mn3ohu7oxx5w",
  "tags": [
    "G01R27/2605",
    "ABB SCHWEIZ AG [CH]"
  ],
  "textContent": "A method of estimating a quantity dependent on a capacitance (Cf) of an electrical filter (14) connected to an AC side (16) of an electrical converter (12) comprises: injecting a plurality of frequency components (42) into a voltage reference (34, 34') of the electrical converter (12), wherein the frequency components (42) have frequencies in a frequency range, where at least one of a resonance frequency (54) and an anti-resonance frequency (52) of the electrical filter (14) is expected; operating the electrical converter (12) with the voltage reference (34, 34') by determining switching commands (28) from the voltage reference (34, 34') and applying the switching commands (28) to the electrical converter (12); determining an AC side voltage (uc) and an AC side current (ic) in the AC side (16) of the electrical converter (12) and determining therefrom a filter admittance (50) and/or filter impedance; determining at least one of a resonance frequency (54) and an anti-resonance frequency (52) of the electrical filter (14) by determining a frequency, where a phase angle of the filter admittance (50) and/or filter impedance switches between a negative value and a positive value; and determining the quantity dependent on the capacitance (Cf) of the electrical filter (14) from the resonance frequency (54) and/or the anti-resonance frequency (52).",
  "title": "FILTER CAPACITANCE ESTIMATION BY RESONANCE FREQUENCY DETERMINATION"
}