Nonlinear Control of a Boost DC/DC Converter for Photovoltaic MPPT Systems Using a TMS320F28379D Microcontroller

This work presents a nonlinear controller of a boost dc/dc power converter for photovoltaic (PV) maximum power point tracking (MPPT) systems. The scheme of the proposed controller consists of the design of a nonlinear controller for the duty cycle generation. For this purpose, a simple and low- cost voltage-oriented controller is proposed in this study. In fact, this control algorithm is suitable to efficiently track fast irradiance changes. Consequently, the efficiency of the overall MPPT system is improved by avoiding loss of PV power caused by i) oscillatory responses due to varying irradiance conditions and ii) load disturbances. In addition, by assuming passivity properties of the constitutive relationship of the load element, internal stability of the closed-loop system is guaranteed for different load conditions, which are applicable for most PV applications. Besides, the internal stability allows to consider load scenarios affected by bounded disturbances. Finally, the proposed MPPT control system is implemented by using a proportional-integral-derivative controller, thereby providing a low-cost solution, which is programmed in the TMS320F28379D DSC Board. Experimental results by considering several scenarios, i.e., i) irradiance changes, ii) changes of setpoint and iii) load disturbances are illustrated to validate the effectiveness of the proposal.