Coordinated control device and control method for distributed photovoltaic grid-connected power generation system

Abstract

The invention provides a cooperative control device of a distributed photovoltaic grid-connected generation system. The device is composed of a single centralized grid-connected inverter and the common direct current bus of a number of MPPT combiner boxes. A voltage coding module is added in a centralized grid-connected inverter. The voltage coding module is located on the common direct current bus on the single centralized grid-connected inverter side. One end is connected with the direct current bus, and the other end is connected with a number of MPPT combiner boxes. Each MPPT combiner box is added with a voltage decoding module, and the voltage decoding module is located on the direct current bus on the combiner box side. A number of voltage decoding modules are correspondingly connected with a voltage coding module. The voltage coding module outputs the common direct current bus voltage reference value for adjusting the inverter to the inverter CPU according to the current instruction of the centralized grid-connected inverter. The voltage change of the common direct current bus is controlled, and the adjustment instruction is transmitted to the MPPT combiner boxes in the form of voltage. The voltage decoding modules identify the issued dispatch instruction according to the voltage of the direct current bus of the combiner boxes and output a control instruction, and the combiner boxes execute the control instruction.

Description

technical field [0001] The present invention relates to a control device and a control method for a distributed photovoltaic grid-connected power generation system with a common DC bus, in particular to a coordinated operation between a centralized grid-connected inverter and multiple combiner boxes with maximum power tracking functions A task scheduling control device and control method. Background technique [0002] Compared with the conventional centralized photovoltaic grid-connected power generation system, the existing centralized grid-connected inverter 102 and multiple combiner boxes 101 with the function of Maximum Power Point Tracking (MPPT) Photovoltaic grid-connected power generation system has higher system power generation efficiency and better system economy, and has gradually attracted the attention of the industry. like figure 1 As shown, in this distributed photovoltaic grid-connected power generation system, the DC output terminals of multiple combiner b...

AI Technical Summary

Problems solved by technology

[0003] However, due to the limitation of the physical distance 104 between devices, the coordinated control between the combiner box and the inverter becomes the key to the performance improvement of the distributed photovoltaic grid-connected power generation system, and the rapidity of data transmission cannot be guaranteed by relying on the traditional remote communication line 105

At present, most products and documents of distributed photovoltaic grid-connected power generation systems adopt the collaborative control method based on remote communication. The single information transmission cycle is above 100 milliseconds, and it is difficult to achieve the response speed required for closed-loop control and cannot achieve ideal system control. Strategy

Especially after the public power system issues a dispatch command to limit the active output power to the distributed photovoltaic grid-connected power generation system, it is difficult to achieve the fast and accurate response effect of the traditional centralized grid-connected power generation system

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