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Microgrid multi-inverter parallel operation control method adopting bus voltage compensation

A multi-inverter, bus voltage technology, applied in the direction of AC network voltage adjustment, multi-phase network asymmetry reduction, AC network to reduce harmonics/ripples, etc. Connecting with three-phase unbalanced load, large amount of program calculation, etc.

Inactive Publication Date: 2015-08-12
国网山东省电力公司聊城供电公司 +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, this patent needs to perform fast Fourier transform on the instantaneous active power and instantaneous reactive power, and detect the power of each characteristic sub-harmonic by frequency division, and then calculate and synthesize the harmonic reference voltage for each characteristic sub-harmonic respectively, specifically The implementation process is too complicated, and the calculation amount of the program is relatively large, which may affect the rapid response speed of the system
In addition, this method is used for single-phase inverter control, mainly used in the occasions where the common bus is connected with non-linear loads, and cannot be applied to occasions with three-phase unbalanced loads
[0011] Chinese patent document CN102437589B discloses a single-phase solar power multi-inverter parallel power sharing control method, which overcomes the shortcomings of PID control for both voltage and current double loops
However, when the microgrid system is connected with a nonlinear load, a large number of harmonics will be generated. This method cannot suppress the harmonics, so this method cannot be applied to the three-phase unbalanced load and nonlinear load connected at the same time. In microgrid system
[0013] In summary, the existing technology does not provide a good solution for the complex operating conditions of the island microgrid system connected with three-phase unbalanced loads and nonlinear loads at the same time

Method used

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  • Microgrid multi-inverter parallel operation control method adopting bus voltage compensation
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  • Microgrid multi-inverter parallel operation control method adopting bus voltage compensation

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Effect test

Embodiment 1

[0107] A micro-grid multi-inverter parallel operation control method using bus voltage compensation, the method operates in an island micro-grid multi-inverter parallel system, and the island micro-grid multi-inverter parallel system includes several distributed power generation units, A common bus, a nonlinear load, a three-phase unbalanced load, and a centralized controller. The distributed power generation units are connected in parallel, and the distributed power generation units are connected to the common bus through feeders. The common bus is equipped with With the nonlinear load, the three-phase unbalanced load and the centralized controller, the distributed power generation unit includes sequentially connected micro-sources, a three-phase full-bridge inverter circuit, a filter inductor L, and a filter capacitor C , feeder, the distributed power generation unit also includes a local controller, a drive protection circuit, and the three-phase full-bridge inverter circuit...

Embodiment 2

[0126] According to the method for controlling the parallel operation of multi-inverters in a microgrid using bus voltage compensation described in Embodiment 1, it is further defined as, in the step (4), respectively extract v oαβ i oαβ The positive sequence component of the fundamental wave, get v oαβ + and i oαβ + , the calculation formula is shown in formula (I):

[0127] v oαβ + = v oα + v oβ + = 1 ...

Embodiment 3

[0130] According to Embodiment 1, a microgrid multi-inverter parallel operation control method using bus voltage compensation is further defined as, in the step (5), the filter capacitor voltage fundamental positive sequence vector v oαβ + and feeder current fundamental wave positive sequence vector i oαβ + Calculate the fundamental positive sequence active power P + and fundamental positive sequence reactive power Q + , the calculation formula is shown in formula (II):

[0131] P + Q + = v oα + v oβ + ...

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Abstract

The invention discloses a microgrid multi-inverter parallel operation control method adopting bus voltage compensation. An integrated controller acquires a common bus voltage and extracts a fundamental negative-sequence component, a characteristic order harmonic positive-sequence component and a characteristic order harmonic negative-sequence component of the common bus voltage, and transmits the common bus voltage components in a dq coordinate system to a local controller of every parallel inverter through low-bandwidth communication. In the local controller, a characteristic order harmonic positive- and negative-sequence compensation voltage vector is calculated and is superposed with a reference voltage vector and a virtual impedance voltage vector to synthesize and correct a voltage regulating reference vector, and imbalance compensation and harmonic suppression of the common bus voltage is carried out through inverter voltage and current control. By applying the method provided by the invention to an island microgrid multi-inverter parallel system in which a common bus is connected with a three-phase imbalance load and a nonlinear load, three-phase voltage balance of the microgrid can be maintained, output voltage distortion of three-phase inverters can be reduced, and output power of the parallel inverters can be accurately allocated.

Description

technical field [0001] The invention relates to a method for controlling the parallel operation of multi-inverters in a microgrid using busbar voltage compensation, and belongs to the technical fields of distributed power generation and smart grids. Background technique [0002] In order to solve the technical problems of connecting distributed power sources to the power grid, scholars related to power systems have proposed the concept of micro-grids. The microgrid is composed of distributed micro-sources, energy conversion devices and local loads interconnected through the network. It is a local power generation system capable of self-control, protection and management, and can operate in two states of islanding and grid-connected. In the microgrid, many distributed micro-sources are connected to the AC bus through the inverter interface, thus forming a multi-inverter parallel operation environment. [0003] In the microgrid composed of three-phase inverters, when the thre...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H02J3/12H02J3/26H02J3/01
CPCY02E40/40Y02E40/50
Inventor 张庆海李洪博刘安华梁甲文王新涛蔡军孔鹏鲍景宽李豹郭峰
Owner 国网山东省电力公司聊城供电公司
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