Direct Current Control of Active Power Filter without Filter Current Measurement

The paper presents a three-phase parallel active power filter without filter current measurement. Only supply grid voltage sensors, filter capacitor voltage sensor and supply line current sensors are used to provide filter’ proper operation, aiming to reduce reactive power and line current distortion, caused by a non-linear load. Due to filter’s inverter-like topology with known parameters in filter branch, the predictive direct current control (DCC) method has been successfully applied, thus obtaining good dynamic response, reducing the commutation frequency of the active power filter’s switches and consequently decreasing the filter branch losses.