Voltage Sensorless Control of Three-Phase PWM Active Power Filter based on the Active Peak Detector

In this study, we present an active peak detection technique (APD) that predicts the input voltage and DC voltage by detecting the input current of a three-phase active power filter (APF). The output voltage is predicted by APD, and the input voltage is predicted using the input current, switching function, and estimated value of DC voltage. The proposed method can be implemented using easy formulas and circuit methods without the need for difficult and complex sampling formulas like the observer. PSIM simulation is performed to prove the feasibility of this study. The input voltage and DC voltage are predicted under the conditions of a 220V voltage, a load of 25Ω, and the DC voltage of the APF changing rapidly in three stages from 430V, and using this, it is possible to control the unit input power factor of the APF system. For a situation where the load suddenly decreased from 25Ω to 15Ω, the results of the method using the sensor and the proposed method are consistent with each other. Lastly, the input power factor(P.F) of the APF according to load changes is 0.99, and the total harmonic distortion (%THD) of the input current is maintained below 8%.