Novel current control method for active power filter based on optimal voltage vector

A novel hysteresis current control method for active power filter based on optimal voltage vector is suggested. The method jointly utilizes two sets of phase current difference comparators to determine the locations of the reference voltage vector and the current error vector. When the system reference voltage vector is changing rapidly and randomly which makes it difficult to estimate its location, the new method can fast detect its correct position by a single try-and-error process which is essential to the performance of active power filter. The related concept and formulation are presented. Computer simulation is conducted on a testing system and the results show that the method can fast determine optimal voltage vector, therefore effectively reduce current tracking error, and in the meanwhile apparently reduce switching frequency of voltage source inverter (VSI) and hence improve efficiency of active power filter noticeably.