Research On Power Quality Monitoring System Of Active Power Filter

With the growing load of electric system, especially the usage non-linear power electronics equipment, power quality in the grid is seriously polluted and the safe and stable operation of power equipment and power grid is threatened. These affect the development of national economy directly. Therefore, power quality monitoring and power quality management have important meanings. Active power filter is one of the most effective way to improve power quality, the real-time monitoring of power quality in grid can analyze the system online and detect the governance effect, the two will accelerate each other, and not a single one can be omitted. Around active power filter harmonic control and the effect, this paper carries out the following work.Firstly the paper describes the research background and significance of the subject, briefly introduces the research status of power quality monitoring and active power filter technology, then expounds the key technology of the active filter compensation system, analyzes the principle of power quality parameters detection.The designs of power quality monitoring system based on active power filter include hardware and software parts. The hardware uses double DSP structure, main DSP chip is responsible for realization of signal acquisition, calculation of harmonic current and power quality parameters, communication with upper-computer; the other one completes the generation of compensation current, the output of PWM signals, the control of busbar voltage and so on. In addition to the controller section, the circuit contains sampling circuits and driver circuits, sampling circuit is constructed by signal conditioner and AD sampling, upper-computer is constructed by communication interface circuit and liquid crystal display circuit. According to the hardware design of control system, the paper takes out the software design, including the main flow chart, the program of compensating current, the program of power quality parameter calculation program and the program of double DSP communication.Finally in the practical engineering application, this paper analyzes the harmonic governance effect of active power filter and the results of power quality parameters monitoring, and verifies the feasibility of harmonic detection algorithm, current compensation strategy, direct-current busbar voltage control and monitor of power quality parameters.