Parallel power active filter new control technique based on modified p-q-r power theory

Abstract

The paper presents the main advantages of using the instantaneous p-q-r power theory to construct high-speed control system for power active filters. It allows to realize both quasi-static and dynamic modes of operation of electric energy consumers with active filter-compensating devices powered by a three-phase four-wire utility grid. At the same time, it has been shown that the use of p-q-r coordinate’s transformations is due to the large number of mathematical calculations performed by the microcontroller in real time and require a high degree of performance of the hardware part of the control system. A new technique for controlling parallel power active filter combining the universal p-q-r power theory with cross-vector theory is proposed. The proposed technique should be used in control systems of power active filters operating for three-phase four-wire electrical systems with electrical load of any type, as well as in hybrid systems, when the power part of the converter can be used not only as a filter-compensating device, but as a voltage inverter. It is shown that the use of the proposed technique can significantly reduce the number of mathematical calculations performed by the control system microcontroller for the implementation of control signals by power transistor modules. The Matlab model of a real power supply system with a parallel power active filter to test the efficiency of the algorithm is synthesized. Comparing the simulation results for the three power active filter control technique allowed to evaluate the quality of the proposed algorithm and to confirm not only its efficiency but also the equivalence of the received power characteristics to the characteristics that were obtained when using the universal p-q-r instantaneous power theory.