# Design and Analysis of a Hybrid MPPT Method for PV Systems Under Partial Shading Conditions
## 3 Results and Discussion
### Operating Scenario of the Overall System: Perturb & Observe MPPT Algorithm  
In this section, PV system simulation with the Perturb & Observe Algorithm is performed. The algorithm tracks the MPP and generates the reference voltage value. The generated signal is applied in the PI controller and comparator to produce the PWM signal. A successful MPP tracking is performed by using the right duty cycle. In the simulation results, the voltage, current and power of the PV array are reviewed. In addition, the PV array voltage has been compared with the reference voltage produced in the Perturb & Observe algorithm. It has been seen that the reference voltage has followed the PV array voltage. The advantageous aspects of this method are determined. The PV array output voltage graph and converter output voltage graph of the system using the Perturb & Observe MPPT algorithm under varying irradiance conditions are seen in Figure 9.  
In addition, the PV array output power and converter output power graph containing the real solar irradiance data are shown in Figure 10.  
PV array output voltage and reference voltage graphs for the Perturb & Observe MPPT method under varying irradiance conditions are shown in Figure 11. The green color represents the PV array voltage and the purple color represents the reference voltage generated in the Perturb & Observe algorithm. It is also shown in close perspective with  
Figure 10: PV array output power and converter output power for the P&O MPPT method with real irradiance. Figure 9: PV array output power and converter output power for the P&O MPPT method. varying irradiance phase. In this scenario, the MPP is successfully followed by the MPPT algorithm. Moreover, compared to the case where the MPPT controller is not used, more stable signals are formed during irradiance changes. In addition, a PV array output voltage and reference voltage graph containing the real solar irradiance data is shown in Figure 12.  
Operating Scenario of the Overall System: Kalman Filter and the Perturb & Observe Hybrid MPPT Algorithm  
In this case, a hybrid Perturb & Observe and Kalman Filter algorithm is tested. PWM signal is generated using the reference voltage. The boost converter is operated and the MPP point is tracked successfully. Voltage, current, power and reference signal comparisons are performed for the PV array and DC-DC boost converter. Since the Kalman Filter is only a mathematical process, it is useful to combine it with the Perturb & Observe method in a hybrid structure as a low-cost solution. The graph shown in Figure 13 is the PV array output power graph and converter output power graph for the KF and P&O Hybrid MPPT method under varying irradiance conditions. In addition, PV array output power and converter output power for KF and P&O Hybrid MPPT method graph containing the real solar irradiance data is shown in Figure 14.  
Figure 11: PV array output voltage and reference voltage for the P&O MPPT method. Figure 12: PV array output voltage and reference voltage for the P&O MPPT method with real irradiance. Figure 15 shows the PV array output voltage and reference voltage graphs. The graph also shows that MPP is tracked successfully. The green color represents the PV array voltage, and the blue color represents the reference voltage generated in the MPPT algorithm. Figure 14: PV array output power and converter output power for the KF and P&O Hybrid MPPT method with real irradiance. Figure 10.0 PV array output power and converter output power for the KF and P&O Hybrid MPPT method. Figure 10.1 PV array output voltage and reference voltage graph for the KF and P&O Hybrid MPPT method.