An Active Power Filter Using a Sensorless Muticell Inverter

Unlike traditional inverters, multicell inverters have the following advantages: lower switching frequency, high number of output levels and less voltage constraints on the IGBT´s. Significant performances are provided with this structure which is constituted with flying capacitors. This paper deals with a predictive and direct control applied to the multicell inverter. To perform the capabilities of multicell active filter, a voltage control method of flying capacitor, based on the use of a switching table, is added. Flying capacitor voltages are kept on a fixed interval and precise voltage sensors are not necessary. The association of predictive control and voltage balancing increases considerably the bandwidth of active filter.