Voltage frequency adjustment method considering photovoltaic maximum power tracking for active power distribution network

Abstract

The invention discloses a voltage frequency adjustment method considering photovoltaic maximum power tracking for an active power distribution network. The voltage frequency adjustment method comprises the following steps of acquiring a reference voltage V<mpp> of a photovoltaic cell in a maximum power running mode; acquiring a DC voltage V<dc> output from the photovoltaic cell; carrying out frequency adjustment on the DC voltage V<dc> to obtain a frequency adjustment quantity Delta Omega; calculating an average value P of active power and an average value Q of reactive power output from a photovoltaic inverter; calculating a droop coefficient of a self-adaptive droop control; obtaining a reference voltage amplitude U<*> and a reference angular frequency Omega' output from an AC side of the photovoltaic inverter after considering the self-adaptive droop control of a circuit impedance factor; obtaining a reference angular frequency Omega' after frequency adjustment; and calculating an input signal U<ref> of a pulse width modulation (PWM) driving circuit of the photovoltaic inverter. By the voltage frequency adjustment method, distributed photovoltaic maximum power can be ensured to be output, and meanwhile, the influence of the circuit impedance is considered; and when a load or an environment changes, active power and reactive power can be accurately allocated to the photovoltaic inverter, and the purpose of improving the reliability of distributed photovoltaic power supply is achieved.

Description

Technical field [0001] The invention relates to a method for adjusting the voltage and frequency of an active power distribution network in consideration of photovoltaic maximum power tracking, and belongs to the technical field of photovoltaic power generation control in an active power distribution network. Background technique [0002] As a clean new energy source, solar energy is increasingly being valued by countries all over the world in the pursuit of a low-carbon society, and it has become one of the effective means to solve environmental problems, energy crises and develop smart grid technology. Distributed photovoltaic access to the active distribution network is the main form of solar power application. Grid-connected inverter is an important device for the interface between photovoltaic power generation and the grid, and its control technology is also one of the research hotspots and difficulties. [0003] Since the output power of distributed photovoltaic power genera...

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Problems solved by technology

[0006] In view of the shortcomings of the existing traditional droop control mentioned in the above background technology, and the problem of DC voltage stability when distributed photovoltaics are connected to the active distribution network, the present invention provides an active distribution network voltage that takes into account the maximum power tracking of photovoltaics. Frequency Adjustment Method

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