DC-LINK


In a variable frequency drive, power conversion schemes are used which incorporate an intermediate stage where energy is processed at DC. A ‘DC-link’ capacitor is fitted at this point to provide a low impedance path for high frequency switching currents and to provide energy storage.


DC-link capacitors • Aluminium electrolytic capacitors


• DC film capacitors • PEC film capacitors


Inrush current limiters / discharge resistors • Housed PTC ICL thermistors


• Leaded PTC ICL thermistors


CONVERSION


At the conversion stage, the DC voltage is converted into an AC voltage at a given but variable voltage and frequency to drive the motor. The conversion circuit typically consists of IGBTs as a full bridge made of discrete semiconductors or supplied in a semiconductor module. Here, snubber capacitors are needed to reduce the overshoots when conducting semiconductors are switched off. Gate-drive transformers are used to switch the IGBT on and off and current-sense transformers are used to measure the current.


Snubber capacitors • MKP film capacitors • MKP snubber capacitors • CeraLink™ capacitors


Temperature measurement • NTC thermistors


EMI suppression chokes • Power chokes for DC BUS


EMI suppression capacitors • Y capacitors


Visit avnet-abacus.eu/inverters for full product information and to view the interactive tool


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