Photovoltaic grid-connected and electric energy quality management unified control strategy

Abstract

The invention discloses a photovoltaic grid-connected and electric energy quality management unified control strategy comprising the following steps that 1) photovoltaic component output is detected in real time, and the operation mode of a photovoltaic grid-connected system is adjusted; when the active grid-connected conditions are not met, the photovoltaic grid-connected system operates in an electric energy quality management mode, and when the active grid-connected conditions are met, the photovoltaic grid-connected system operates in an active grid-connected and electric energy quality management unified mode; and 2) when the photovoltaic grid-connected system operates in the active grid-connected and electric energy quality management unified mode, the photovoltaic grid-connected system allocates residual capacity of the photovoltaic grid-connected system according to priority of reactive power and harmonic compensation firstly and then integrates command current based on the instantaneous power theory. Compared with conventional methods, the photovoltaic grid-connected system is enabled to have a function of actively participating in power gird electric energy quality management on the basis of maintaining the original functions so that utilization rate of an inverter is enhanced, use of an electric energy quality management device is reduced and cost is saved.

Description

technical field [0001] The invention relates to a unified control strategy for photovoltaic grid connection and power quality management, which belongs to the research field of power electronics technology and power quality management. Background technique [0002] With the urgent demand for new energy from social development and the increasingly mature photovoltaic power generation technology, photovoltaic power generation has entered the stage of large-scale promotion. However, due to the randomness and intermittent nature of illumination, there are problems such as low utilization of photovoltaic inverters and poor economic benefits of the system. On the other hand, with the emergence of a large number of nonlinear and impact loads in the power grid, the pollution of the generated harmonics and reactive currents to the public power grid is also becoming more and more serious, requiring a large number of compensation devices to improve power quality, but additional compens...

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Problems solved by technology

The basic strategy of the above research is to use the remaining capacity of active grid connection for power quality control, but it does not consider the compensation strategy when the remaining capacity cannot meet the full compensation of reactive power harmonics; and does not conduct in-depth research on the system operation mode; the above Most of the research is theoretical research and simulation verification, and no complete system implementation has been seen

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