Comprehensive Controller Implementation for Wind-PV-Diesel Based Standalone Microgrid

 ABSTRACT:

  In this paper, a comprehensive controller of a standalone microgrid is implemented, which has three dispersed generation units based on a wind, solar photovoltaic array and a diesel generator. The power ratio variable step perturb and observe method is applied to achieve maximum power point tacking of a solar photovoltaic array and a variable speed wind turbine coupled a permanent magnet brushless DC generator without rotor/wind speed sensors. Moreover, to ensure perfect synchronization of a diesel generator to the point of common coupling (PCC), a control algorithm is developed, which is based on in-phase and quadrature units. An active power control based on proportional-integral controller with anti-windup, is used for voltage and frequency regulation. The LCL filter based on virtual resistor, is used for power quality improvement at PCC. Simulation and test results are presented for the validation of proposed system using a prototype of 2 kW in the laboratory.

KEYWORDS:

1.      Standalone microgrid

2.      Solar photovoltaic array

3.      Wind turbine

4.      Diesel generator

5.      Active damping

6.      LCL filter based virtual resistor

7.      PCC voltage regulation

8.      power quality improvement and PI controller with anti-windup

SOFTWARE: MATLAB/SIMULINK

CONCLUSION:

The proposed microgrid for an isolated water treatment station based on three dispersed generation units; fixed speed DG, variable speed wind turbine and solar photovoltaic array, has been found to operate safely at sever conditions while supplying the load demand continuously at regulated voltage. The power ratio variable step P&O method for MPPT, has easily been implemented in a prototype to achieve high level of performance from wind turbine and solar photovoltaic array without any wind/speed sensors and without oscillations around MPP. The developed active power control based on AWPI controller with virtual resistor based active-damping for voltage regulation at PCC, has been implemented effectively and obtained results have demonstrated desired performance without saturation issue during transitions. The BES is protected from overcharging with utilization of excess power for space heating system as a DC dump load. DG has been used only as a backup energy source and its synchronization with PCC has been achieved safely without destabilizing the system operation. Switching harmonics are perfectly attenuated without losses using LCL filter based virtual resistor. Therefore, it is concluded that the comprehensive control proposed in this work for wind-solar diesel based standalone microgrid, is expected to be an effective alternative for uninterrupted supply in remote and isolated areas.

 REFERENCES:

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