Abstract: In voltage-source inverters, capacitors are added to the DC link to filter the output of the rectifier circuit. Theoretically, the larger the capacitor value, the smaller the voltage ripple. However, this is not feasible from the perspective of space and cost. This paper discusses in detail the calculation method of filter capacitors for three-phase input and single-phase input inverters, providing a theoretical basis for selecting filter capacitors required for loads of different power in voltage-source inverters. Finally, experiments prove that the algorithm is feasible and reliable, which not only ensures product performance but also saves costs. Keywords : rectifier circuit; voltage-source inverter; ripple [b][align=center]Computing Method of the Filter Capacitors of DC-link in Voltage Source Inverters WANG Qing-song (College of Electrical Engineering, Zhejiang University, Hangzhou, Zhejiang 310027, China)[/align][/b] However, taking space and current into account, it is not reliable to add many capacitors. The calculation method of the filter capacitors of three-phase inverters and single-phase ones is illustrated. Based on this method, the proper capacitors can be easily selected for different power loads. The method has been proven useful and reliable by experimental results. Using this method, the product performance is improved and the cost is also reduced. Keywords: rectifier circuits; voltage source inverters; tips 0 Introduction Although AC power can be converted into DC power using rectifier circuits, in three-phase circuits, this DC voltage or current contains voltage or current ripple with a frequency six times the power supply frequency. In addition, the inverter circuit of the frequency converter will also generate ripple voltage or current due to output and carrier frequency, which in turn affects the quality of DC voltage or current. Therefore, in order to ensure that the inverter circuit and control circuit can obtain high-quality DC voltage or current, the DC voltage or current must be filtered to reduce voltage or current ripple. [b][align=center]For details, please click: A Calculation Method for DC Link Filter Capacitors in Voltage-Type Frequency Inverters[/align][/b]