A low-voltage ride-through control method for distributed photovoltaic power generation systems

A photovoltaic power generation system and low voltage ride-through technology, applied in photovoltaic power generation, information technology support systems, electrical components, etc., can solve the problems of slow recovery rate of active power, unstable working status of intelligent MPPT combiner boxes and inverters, etc. Achieve the effect of reducing complexity, meeting low voltage ride-through requirements, and small lift amplitude

CN106786737BActive Publication Date: 2019-03-08GUODIAN NANJING AUTOMATION
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Patent Information

Authority / Receiving Office
CN · China
Patent Type
Patents(China)
Current Assignee / Owner
Publication Date
2019-03-08

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Abstract

The invention discloses a low-voltage ride-through control method for a distributed photovoltaic power generation system. An inverter of the distributed photovoltaic power generation system is used for detecting the falling depth of network voltage in real time on the basis of a direct-current voltage outer loop and a network voltage feedforward decoupling control current inner loop based on dq conversion, so that a low-voltage ride-through control mode and a low-voltage ride-through recovery mode are carried out; and an intelligent MPPT combiner box of the distributed photovoltaic power generation system is used for judging a direct-current bus voltage overvoltage condition in real time on the basis of respective input voltage outer loop and input current inner loop, so that direct-current bus overvoltage control mode and a direct-current bus overvoltage recovery control mode are carried out. The method solves the problem that active power cannot be recovered quickly after direct-current bus voltage out-of-control and low-voltage ride-through recovery in the low-voltage ride-through process of the distributed power generation system.
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Description

technical field

[0001] The invention relates to a low-voltage ride-through control method for a distributed photovoltaic power generation system, and belongs to the technical field of photovoltaic grid-connected power generation. Background technique

[0002] The distributed photovoltaic power generation system combines the advantages of centralized and string inverters. It not only has the advantages of multi-channel MPPT tracking, increased power generation, but also has the advantages of high power quality, and finally achieves high efficiency, reliability and high profitability.

[0003] Both the distributed photovoltaic power generation system and the string inverter adopt two-stage power conversion. The two-stage power conversion of the string inverter is controlled by the same controller, which is convenient for coordination and simple to control; while in the distributed photovoltaic power generation system, the two-stage power conversion of DC / DC boost and DC / AC inv...

Examples

Embodiment Construction

[0046] The present invention will be further described below. The following examples are only used to illustrate the technical solution of the present invention more clearly, but not to limit the protection scope of the present invention.

[0047] Please refer to figure 1 , a photovoltaic square array in the distributed photovoltaic power generation system is composed of m intelligent MPPT combiner boxes and an inverter. The DC outputs of m smart MPPT combiner boxes are all connected in parallel to the DC bus (DC-link) of the inverter through m DC circuit breakers.

[0048] Each intelligent MPPT combiner box contains n channels of BOOST circuits. The input voltages of the n channels of BOOST circuits are Uin_1, Uin_2,...,Uin_n, the input currents of the n channels are Iin_1, Iin_2,...,Iin_n, the DC bus voltage Udc, and the inverter AC grid voltage Ue.

[0049] 1. Please refer to the inverter control strategy figure 2 . The inverter controls the DC bus voltage, and adopts...