# The essence of maximum power point tracking

Since the PV characteristic of photovoltaic modules is a single-peak nonlinear curve, the maximum power point of the photovoltaic array composed of its series and parallel connections will also be affected by the light intensity and the surface temperature of the photovoltaic array. Therefore, how to track the maximum power point of the photovoltaic array is important for improving The overall efficiency of the system is extremely important.
⑴ The essence of maximum power point tracking
Under different light intensity and temperature, the photovoltaic array has a corresponding maximum power point. The external environmental factors are usually unable to be changed artificially. Temperature and light intensity always change throughout the day, so the output characteristics of the photovoltaic array also change accordingly. If the photovoltaic array can always output the maximum power, it must be controlled in time.

⑵ Maximum power point tracking method
There are many methods to achieve the maximum power point tracking of photovoltaic arrays, which can be roughly divided into two categories: one is the indirect maximum power point tracking method, which is called the quasi maximum power point tracking method; the other is the direct maximum power point tracking method. The tracking method is called the true maximum power point tracking method. This chapter uses the general circuit diagram in Figure 2 as an example to explain and analyze two types of methods. Among them, Vo And Io It is the output voltage and current of the DC/DC converter.

① Quasi-maximum power point tracking method
Ⅰ. Curve fitting method
Ⅱ. Look-up table method
Ⅲ. Constant voltage method
Ⅳ. Open circuit voltage proportional coefficient method
Ⅴ. Short-circuit current proportional coefficient method
Ⅵ. Finite period current perturbation method
②True maximum power point tracking method
Ⅰ. Disturbance observation method
Ⅱ. Incremental conductance method
Ⅲ. Intermittent variable step size search method
Ⅳ. Power step method
Ⅴ. Fuzzy control method
Ⅵ. Neural network control method

⑶MPPT method comparison
Table compares the MPPT methods in terms of detecting physical quantities, tracking speed, tracking power fluctuations in steady state, adaptability to environmental changes, and difficulty in execution. Throughout the various methods, each has its own advantages and disadvantages. Therefore, only the organic combination of several methods, complementing the short and long, can obtain the best maximum power point tracking effect.