Photovoltaic Power Generation System Based On Passive Control Mppt Technology Research

There is only one part of the energy conversion in the single-stage photovoltaic (PV)grid-connected system, where the power delivered to the grid changes along with thechange of the output power of photovoltaic array, and which is by the influence of factorssuch as external illumination intensity, temperature and load, etc. Thus, it’s necessary tomake the control of the operating point of photovoltaic array working at a maximum powerpoint continuously and stably, which can improve the whole efficiency of the system inorder to take full advantage of solar energy resources.In the single-stage photovoltaic (PV) grid-connected system, the inverter controlsystem needs to simultaneously realize maximum power point tracking of photovoltaicarray and grid control. In this paper, the inverter adopts passivity power control strategybased on the euler-lagrange model, which can obtain decoupling control of output activepower and reactive power. And in order to realize maximum power point tracking ofphotovoltaic array, considering MPPT algorithm and passivity power control theory needto be combined. Under the precondition of ignoring switch loss and line loss, it is knownthat we can change the working point of photovoltaic array by adjusting the active powerof the inverter output according to the power balance principle between photovoltaic dcside and inverter output side. Thus, we can set the expected active power of the inverteroutput through controlling and changing the output power of MPPT module, so as toachieve the purpose of tracking the maximum power point.Under the support of funding project "power converter and ac motor nonlinear controlresearch"(PHR201007130) for academic human resources development in institutions ofhigher learning under the jurisdiction of Beijing municipality, this paper proposes amaximum power point tracking algorithm based on power control, which directly selectsthe output power of photovoltaic array as a control variable, and with the passivity powercontrol strategy of inverter applied to the single-stage photovoltaic (PV) grid-connectedsystem with the capacity of1.8kVA. Through conducting the simulation and experimentalresearch, the results show that the maximum power point tracking algorithm based onpower control is feasible, which can meet with the requirements of response speed,tracking accuracy and stable dc bus capacitor voltage simultaneously, and has a certaintheoretical and practical significance in improving the energy utilization of photovoltaic array and really realizing the energy "green transformation".