This paper being an adaptive proportional resonant (PR) controller for single phase grid connected inverter that modify its control parameters to grid impedance change. Forth order band bass filter is method and then combine with the adaptive system for on-line detection of any variations in the resonance frequency. The estimated frequency is then prepared by mathematical signal processing operation to identify the variations in the grid impedance. For the on–line tuning of the PR parameters, a look-up table technique is apply and its parameters are linked with the measure impedance values. Simulation results based on MATLAB environment clearly verify the effectiveness of the proposed control scheme for 2 kW grid connected inverter system.
Fig. 1. Block diagram of the proposed adaptive PR controller.
EXPECTED SIMULATION RESULTS:
Fig. 2. Simulation result of emulated grid voltage.
Fig.3. FFT analysis of grid current. (a) APR controller. (b).PR controller.
Fig. 4. Online adaptation of the APR control parameters.
Fig. 5. Grid voltage and current waveforms under changeable grid
impedance with the proposed control strategy.
A new control strategy based on an adaptive proportional resonant (APR) controller has been grown and successfully proved on a simulated 2 kW single phase grid tide PV inverter. A fourth order Sallen-Key band pass filter tailored to the system to taking the harmonic components around the resonant frequency has been execute. data signal processing method was employed in order to provide the controller with signals compare to the variable grid impedance. A large low level of current total harmonic distortion (THD) is reach in comparison with conventional PR controller and submission with IEEE929-Standard has been show.
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