A Voltage Sensorless Control of a Three Phase Grid Connected Inverter Based on Lyapunov Energy Function Under Unbalanced Grid Voltage Condition

2018 ◽  
Author(s):  
Vikram Roy Chowdhury ◽  
Subhajyoti Mukherjee ◽  
Jonathan Kimball
Keyword(s):  
Energy Function ◽  
Sensorless Control ◽  
Grid Voltage ◽  
Three Phase ◽  
Grid Connected Inverter ◽  
Lyapunov Energy Function ◽  
Unbalanced Grid

Modified Power Compensation Control Strategy of Three-Phase Grid-Connected Inverter under Unbalanced Grid Voltage Conditions

2015 ◽  
Vol 740 ◽  
pp. 335-338 ◽  
Author(s):  
Shao Hua Sun ◽  
Hong Qi Ben
Keyword(s):  
Control Strategy ◽  
Reactive Power ◽  
Positive Sequence ◽  
Grid Voltage ◽  
Compensation Control ◽  
Active And Reactive Power ◽  
Three Phase ◽  
Grid Connected Inverter ◽  
Three Phase Inverter ◽  
Unbalanced Grid

Control strategy under unbalanced grid voltage conditions is one of the most important issues for grid-connected inverter. Under unbalanced grid voltage conditions, the 2nd active and reactive power ripples generate, they pollute the grid. To meet the demands of IEEE Std.929-2000, this paper proposed a modified power compensation control strategy; the proposed solution is based on direct power control. To provide accurate compensating power, the power model of three-phase inverter under unbalanced grid voltage conditions is given, using the positive sequence current component and the negative sequence voltage component, the compensating powers are calculated in details. Theoretical analysis and comparative simulation verification are presented to demonstrate the effectiveness of the proposed control strategy.

The Analysis of the Grid-Connected Phase-Locked Loop Technologies Based on the Transformation of Coordinate System

2012 ◽  
Vol 220-223 ◽  
pp. 1175-1180
Author(s):  
Guo Tao Yang ◽  
Zhi Yi Sun ◽  
Li Qun Liu
Keyword(s):  
Simulation Analysis ◽  
Phase Locked Loop ◽  
Phase Voltage ◽  
Grid Voltage ◽  
Advantages And Disadvantages ◽  
Pv Inverter ◽  
Three Phase ◽  
Failure Conditions ◽  
Grid Connected Inverter ◽  
Generating System

In order to gain the same amplitude、frequency and phase between the output voltage of the inverter and the grid voltage, the phase-locked loop (PLL) technology is widely used in grid-connected photovoltaic (PV) generating system, which is normally used to obtain instantaneous phase information to achieve the grid-connected purpose of PV inverter. The detective accuracy of frequency and phase of the grid voltage is directly affected by the PLL. Two software PLL technologies are compared by using the simulation analysis which is based on the d-q transformation. To provide the basis for the design of grid-connected inverter, the advantages and disadvantages of two software PLL technologies are analyzed under different grid failure conditions, such as one phase voltage dropped, two of three phase voltage (TPV) dropped, grid frequency mutated, and grid voltage offset, etc. Particularly, the appropriate PLL technology can effectively improve the grid-connected ability of PV inverter under the grid voltage offset or unbalance conditions.

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