Temperature of a link capacitor

A method for monitoring and processing of capacitor temperature, comprising:

• determining the capacitor temperature of a link capacitor by:
• modeling the link capacitor as a series interconnection of an equivalent capacitance (CS) and an equivalent series resistance (ESR), wherein a modeled capacitor current (iCm) flows across the equivalent series resistance (ESR);
• calculating a modeled capacitor power loss (PC) from the modeled capacitor current (iCm) and a value of the equivalent series resistance (ESR) by a first relationship PC=f(iCm,ESR);
• and
• determining, from the modeled capacitor power loss, the capacitor temperature via a specified temperature model, wherein the modeled capacitor current (iCm) is modeled by using a measured capacitor voltage (uC) and the equivalent capacitance (CS) via a second relationship of the form iCm=f(uC,CS);
• and
• monitoring and processing the determined capacitor temperature.

A method to determine a temporal progression of a capacitor temperature and to determine a remaining service life of a link capacitor from the temporal progression of the capacitor temperature by a specified relationship, comprising:

• determining the capacitor temperature of a link capacitor by:
• modeling the link capacitor as a series interconnection of an equivalent capacitance (CS) and an equivalent series resistance (ESR), wherein a modeled capacitor current (iCm) flows across the equivalent series resistance (ESR);
• calculating a modeled capacitor power loss (PC) from the modeled capacitor current (iCm) and a value of the equivalent series resistance (ESR) by a first relationship PC=f(iCm,ESR);
• and
• determining, from the modeled capacitor power loss, the capacitor temperature via a specified temperature model, wherein the modeled capacitor current (iCm) is modeled by using a measured capacitor voltage (uC) and the equivalent capacitance (CS) via a second relationship of the form iCm=f(uC,CS);
• determining the temporal progression of the determined capacitor temperature;
• and
• determining the remaining service life of the link capacitor from the determined temporal progression of the capacitor temperature.