###### Abstract
An operating point at the steady-state condition of the conventional perturb and observe (P&O), and incremental conductance (INC) MPPT techniques under PSCs revolves around a GMPP or LMPP, and generates low tracking speed, resulting in continuous power oscillations equal to changes in a predetermined perturbation size [11]. Power oscillations can be extreme since the conventional algorithms continue to search for the operating point on the P-V curve at steady-state condition (SSC), although the MPP is tracked earlier [13]. A PI-based P&O algorithm was developed to maintain the output reference voltage of the converter and tracking the MPP of the PV array with reduced power oscillations [14]. A P&O-based voltage regulation loop is designed with a PID controller to increase the tracking speed of the MPP and regulate the output reference voltage faster than the conventional P&O algorithm [15]. A PI-based INC-MPPT algorithm was designed to remove the dilemma of choosing the step size of the converter duty cycle under abruptly changing solar irradiance and temperature [16]. An improved hill-climbing double closed-loop algorithm was deployed nearer to the MPP to reduce steady-state oscillations and a rise time when solar insolation is in dynamic condition [17]. An adaptive PID controller with the P&O MPPT algorithm for a PV system is proposed in [18] to improve tracking time and reduce oscillation around MPP. In [19], PID-integrated P&O MPPT is proposed for a grid-connected PV system. The main constraints of these developed MPPT schemes are in making delays in the tracking of MPP and generating greater power oscillations because their operating points are lost to the local MPPs (LMPPs) under PSCs [20]. By taking into account the drawbacks of the previously developed MPPT techniques, in this present study, a PI-based coordinated MPPT technique is proposed for a grid-tied PV system to improve tracking speed and reduce oscillations in PV output power under PSCs [21]. To make zero steady-state errors of the output voltage and current of the PV system, PI controllers are used whose outputs are sent through an incremental conductance (INC) algorithm to regulate the dc-dc converter duty cycle. The advantage of the proposed PI coordinated MPPT method is it can track the GMPP directly instead of looking for multiple LMPPs on the P-V curve, which results in faster tracking speed and low steady-state power oscillations of the PV system. An H-bridge voltage source inverter (VSI) is deployed between a DC/DC converter and utility grid to inject a sinusoidal grid current of 50 Hz with zero steady-state error (SSE), and least total harmonic distortion (THD). A proportional resonant (PR) controller is used instead of a PI compensator in the inverter control system to eliminate the SSE of the referenced grid current, and voltage [22] and sinusoidal pulse width modulation (SPWM) is used to generate control signals. The performance of the proposed MPPT technique is validated in the MATLAB/Simulink platform for different PSCs and a laboratory setup is developed to experimentally validate the performance of the proposed MPPT algorithm. Finally, to prove the effectiveness of the proposed MPPT technique, its performance is compared with conventional INC and perturb and observe (P&O) methods.