Maximum power point tracking on stand-alone solar power system: Three-point-weighting method incorporating mid-point tracking

• Present a three-point-weighting method using mid-point tracking (3PW + MPT) to enhance MPPT performance.
• Verification done on PSIM and hardware tests for a stand-alone solar power system.
• Improving the deficiency of P&O that cannot begin to track from the open-circuit voltage.
• 3PW + MPT tracks better and faster than three-point-weighting method.

This paper proposes a three-point-weighting method that incorporates mid-point tracking to improve the drawback of the perturbation and observation method and to enhance the efficiency of the three-point-weighting method. A design was simulated with PSIM, followed by hardware tests of a stand-alone solar power system using real-time Matlab/Simulink hardware-in-the-loop, for observing the efficiency of the perturbation and observation method, the three-point-weighting method, and the proposed method. It was found that the proposed method tracked better than the three-point-weighting method, and it was capable of improving the deficiency of perturbation and observation method that has difficulty to track from the open-circuit voltage (on the right hand side of the P–V curve) as well as enhancing the precision of the three-point-weighting method in the case of zero-weight.