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A control method, host, slave, and system for parallel inverters

A control method and inverter technology, which is applied in photovoltaic power generation, AC network circuits, electrical components, etc., can solve problems such as the large influence of parallel systems, and achieve the effect of small power disturbance and favorable system stability

Active Publication Date: 2017-01-18
SUNGROW POWER SUPPLY CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] However, for multiple parallel inverters in the master-slave mode, when the master fails due to failures and other reasons, other slaves will not be able to work smoothly, which will have a greater impact on the parallel system

Method used

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  • A control method, host, slave, and system for parallel inverters
  • A control method, host, slave, and system for parallel inverters
  • A control method, host, slave, and system for parallel inverters

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Embodiment 1

[0045] see figure 1 , which is a flow chart of Embodiment 1 of the control method for parallel inverters provided by the present invention.

[0046] The control method for parallel inverters provided in this embodiment is applicable to a system in which at least two inverters are connected in parallel. The DC side and the AC side of all inverters are also connected in parallel. The inverter is used as a slave; for details, please refer to figure 2 The photovoltaic power generation system with inverters connected in parallel is shown. figure 2The output end of the inverter is connected in parallel to the AC bus through a filter circuit. The inverter adopts LCL filter (or other types of filters such as LC), L1~Ln are bridge arm side filter inductors, C1~Cn are filter capacitors, Lg1~Lgn are grid side filter inductors; Lg is grid equivalent Impedance; T is a double-winding step-up transformer.

[0047] The method includes the following steps:

[0048] S101: All slaves rece...

Embodiment 2

[0057] see Figure 5 , which is a flow chart of Embodiment 2 of the control method for parallel inverters provided by the present invention.

[0058] S501: The host uses the maximum power point tracking algorithm to perform MPPT to obtain the voltage value corresponding to the maximum power point;

[0059] S502: The host controls the DC voltage loop according to the voltage value to obtain a current value;

[0060] S503: The master obtains an evenly divided reference current signal according to the current value and the number of inverters, and sends the reference current signal to all slaves; and all or part of the variables, parameters and DC All or part of the variables and parameters of the voltage loop control algorithm are sent to all slave machines.

[0061] S504: Backup the variables and parameters sent by the host, and perform current loop control according to the reference current signal.

[0062] S505: After judging that the master is invalid, all slaves that mee...

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Abstract

The invention provides a parallel inverter control method and system. The parallel inverter control method includes the steps that all slave machines receive all or part of variables and parameters of a maximum power point tracking algorithm, all or part of variables and parameters of a direct current voltage loop control algorithm and evenly-divided benchmark current signals, all or part of variables and parameters of a maximum power point tracking algorithm, all or part of variables and parameters of a direct current voltage loop control algorithm and evenly-divided benchmark current signals are sent by a host, and all the slave machines back up the variables and parameters of the maximum power point tracking algorithm and the variables and parameters of the direct current voltage loop control algorithm; When the slave machines judge that the host fails, one of the slave machines becomes a new host, the backup of the variables and parameters of the maximum power point tracking algorithm and the variables and parameters of the direct current voltage loop control algorithm are utilized for initializing the variables and parameters of maximum power point tracking and a direct current voltage loop, controlling and the even division of new benchmark current signals are carried out, and the evenly divided benchmark current signals are sent to the other slave machines. The parallel inverter control method has the advantages that the other slave machines can continue to work normally and power grid after the host fails, and no generated energy is wasted.

Description

technical field [0001] The invention relates to the technical field of photovoltaic inverters, in particular to a control method, a master, a slave and a system for a parallel inverter. Background technique [0002] With the continuous expansion of the capacity of new energy power stations, in order to realize the optimal allocation of grid-connected inverter capacity and realize the single-machine WM-level solution, the parallel connection of inverters has become a trend of technological development. Parallel inverters have the advantages of convenient expansion, reduced system cost, and improved system efficiency, but increase the complexity of control. [0003] At present, most of the control of parallel inverters adopts the master-slave mode, that is, one of the inverters acts as the master to complete MPPT tracking and voltage loop control, and its output distributes current commands to other parallel inverters through the current sharing link. . The master-slave mode...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H02J3/38
CPCH02J3/383H02J3/385Y02E10/56
Inventor 程林潘年安王志成陶磊
Owner SUNGROW POWER SUPPLY CO LTD
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