Compound control method for fast and accurate tracking control of maximum power point of photovoltaic power generation system

Abstract

The invention relates to a compound control method for the fast and accurate tracking control of the maximum power of a photovoltaic power generation system The photovoltaic power generation system samples the output voltage upv, the current ipv and the working temperature T of the current time of a photovoltaic battery array in real time; photovoltaic output power Ppv (k) is calculated on line and compared with the power Ppv (k-1) of previous time; and if power deviation is larger than a set error range e, a controller fast regulates the output voltage upv by adopting a constant voltage improvement control method till the output power deviation is smaller than the set error range e and then carries out the further accurate tracking control of the maximum power by adopting an admittance incremental method till power error is approximately equal to zero, therefore the purpose of the fast tracking control is achieved. The compound control method can be applied to a photovoltaic power generation MPPT (Maximum Power Point Tracking) control system controlled by adopting an MCU (Microprogrammed Control Unit) or DSP (Digital Signal Processor) chip and has the characteristics of fast response and accurate control.

Description

technical field [0001] The invention relates to a control system for solar photovoltaic power generation, in particular to a compound control method for quickly and accurately tracking the maximum power point of a photovoltaic power generation system. Background technique [0002] In recent years, solar photovoltaic power generation technology has developed rapidly. Due to the obvious nonlinear output characteristics of photovoltaic cells, the maximum power can only be output at a certain voltage. In order to improve the energy conversion efficiency of the system, an appropriate maximum power point tracking algorithm (MPPT) must be used to control the photovoltaic power generation converter to ensure that the system Always operate at the maximum power point of the PV array. At present, the common maximum power point tracking control methods include constant voltage control method, disturbance observation method and admittance increment method, etc., but different methods ha...

AI Technical Summary

Problems solved by technology

At present, the common maximum power point tracking control methods include constant voltage control method, disturbance observation method and admittance increment method, etc., but different methods have different advantages and disadvantages in actual use.

The constant voltage control method is a simplified maximum power point tracking method. Its advantage is that the control is simple and easy to implement. However, this tracking method ignores the influence of temperature on the output voltage of the photovoltaic array and cannot completely track the PV array in all temperature environments. Maximum power, MPPT control accuracy and control adaptability are poor

The incremental admittance method realizes maximum power tracking by comparing the instantaneous conductance and conductance variation of the photovoltaic array. It has the advantages of good control effect and high control stability, but its control algorithm is complex and requires high control system. Poor real-time performance

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