Improved incremental-conductance MPPT algorithm for the photovoltaic system

The surrounding illumination and temperature conditions of photovoltaic (PV) systems are often non-constant. To achieve a higher power output, it is essential to employ Maximum Power Point Tracking (MPPT) methods, which allow the system to adjust promptly in response to changes in illumination and temperature. Among all MPPT methods, the Incremental Conductance (INC) technique is extensively adopted because of its ease of understanding and implementation. However, the traditional INC MPPT method relies on a fixed duty cycle step size, which restricts the tracking speed and often leads to large oscillations around the MPP. In this article, an improved INC (IMINC) method is put forward to solve these problems. On the P-V characteristic curve of PV modules, by comparing the slope value corresponding to this point and a slope threshold F, this technique automatically determines the next step size according to the actual circuit voltage and current, thus overcoming the limitations of fixed step sizes and enabling faster system tracking. Moreover, the proposed approach uses the steady-state judgment threshold J to expand the range of the MPP, facilitating the system to achieve a higher power output, a faster response time, and an enhanced stability. Subsequently, simulations comparing the performance of the traditional INC and the proposed IMINC methods are conducted, and the results validate the superiority of IMINC.