Research On The Photovoltaic Grid-connected Power Conditioner System With The Function Of Power Quality Control

The photovoltaic grid-connected power conditioner(PVPC) combines the using ofgreen energy source and power quality improving. It could generate power, improve thepower quality and reduce dissipation with integration of the control of photovoltaic powergeneration, reactive power compensation and active power filter. The research on thePVPC system was getting more and more attention with the application expending. Thestudy on this area of started later in our country, so the effect was not ideal. This paper isdedicated to the study of the PVPC system, especially the control part.In this paper, the topologies and the control principle of the photovoltaicgrid-connected inverters and active power filter(APF) was analyzed. It can be found thatthe feature was similar with each other. So the PVPC system integrated the photovoltaicpower generation and APF was introduced here. Two staged control is adopted in the frontstage of the system, which can realize Maximum Power Point Tracking(MPPT) of DCphotovoltaic cell and voltage got raised to meet the need of backward stage. In thebackward stage of the system, two method of harmonic compensation are introduced here.The system can generate photovoltaic power and improve the power quality of the grid.The ip-iqmethod based on the instantaneous reactive power theory was employed todetect the harmonic current in the condition of detection can be easy applied. And theactive current was obtained according to the active power of photovoltaic powergeneration. The system can be control by the command current which is the sum ofharmonic current and active current. If the harmonic source was far from the converter, theip-iqmethod cannot be executed. The harmonic attenuation scheme base on the PCCvoltage should be applied. And the harmonic voltage that caused by the harmonic currentand distributed impedance would be detected. With the principle the harmonic wastransferred to the command current to control the system. Traditional PI control cannotastatic control the system in the synchronous rotational coordinates. So a current controlbase PI and resonant regulators(PIR) is proposed to smoothing with specific harmonic. Itcould be used in the PVPC to control the current. In this paper the simulation model of the PVPC was established with Matlab on thefoundation of the control principle and the mathematical model. The performance and thefeasibility of control system were simulated and analyzed through the way of parameteradjustment. To further verify the validity of the system, the experimental platform wasdesigned and constructed with the control core of TMS320F2812. The system wascontrolled by the program. The results of experiment proved that the PVPC system couldwork stably and effective with both of the control scheme. It could achieve the function ofphotovoltaic power generation, reactive power compensation and harmonic attenuation atthe same time.