1. Introduction
Photovoltaic power generation is a technology that uses solar energy to convert light energy into electricity. In the photovoltaic power generation system, in order to obtain the maximum power generation power, it is necessary to track the change of solar radiation intensity in real time, and adjust the working state of the photovoltaic module to keep near the maximum power point. This paper introduces the principle and application of the maximum power point tracking algorithm for photovoltaic power generation.
2. Principle of maximum power point tracking algorithm
In a photovoltaic power generation system, the output power of the photovoltaic module is related to its operating point. The operating point is determined by the voltage and current of the component. Therefore, by adjusting the working state of the component so that it works near the maximum power point, the maximum power generation efficiency can be achieved.
The maximum power point tracking algorithm is realized by monitoring the solar radiation intensity in real time and adjusting the working state of the module according to the monitoring result. Commonly used maximum power point tracking algorithms are as follows:
2.1 Perturb and Observe (P&O) algorithm
P&O algorithm is a simple and widely used maximum power point tracking algorithm. The principle is to determine the maximum power point by continuously disturbing the working state of the component and then observing the change in power.
The specific steps are as follows:
1. Initialize the working state, including voltage and current.
2. Measure the current power.
3. Increase or decrease the value of voltage or current and measure the new power.
4. Compare the old and new power, if the new power is greater than the old power, continue to increase or decrease the value of voltage or current; If the new power is less than the old power, change the direction and reduce the step size.
5. Repeat Steps 3 and 4 until the maximum power point is reached.
P&O algorithm is simple and easy to implement, but because it is based on local search method, it is easy to be disturbed by noise and shadow.
2.2 Incremental Conductance (INC) algorithm
INC algorithm is a maximum power point tracking algorithm based on differential method. The principle is to achieve maximum power point tracking by adjusting the working state according to the admittance characteristics of the component.
The specific steps are as follows:
1. Initialize the working state, including voltage and current.
2. Measure the current output power and admittance.
3. Adjust the working state according to the comparison between the current admittance and the previous admittance:
- If admittance increases, the value of voltage or current is increased;
- If the admittance is reduced, the value of the voltage or current is reduced;
- If the admittance is unchanged, keep the current working state.
4. Repeat Steps 2 and 3 until the maximum power point is reached.
Compared with P&O algorithm, INC algorithm has faster response speed and better stability, but it also has certain computational complexity.
3. Application of maximum power point tracking algorithm
Maximum power point tracking algorithm is widely used in photovoltaic power generation system to improve power generation efficiency and reduce energy loss. The following are some examples of the maximum power point tracking algorithm in practical applications:
3.1 Photovoltaic Power Station
Photovoltaic power stations are the most common photovoltaic power generation system. In photovoltaic power stations, by using the maximum power point tracking algorithm, the working state of the component can be adjusted in real time so that it always works near the maximum power point. This not only improves power generation efficiency, but also extends component life.
3.2 Photovoltaic Street Lights
Photovoltaic street lamp is a kind of equipment that uses solar energy for lighting. By using the maximum power point tracking algorithm, it is possible to ensure that photovoltaic street lights always work at maximum power in the case of changes in solar radiation intensity, thus providing longer lighting time.
3.3 Photovoltaic battery charger
A photovoltaic battery charger is a device that uses solar energy to charge batteries. By using the maximum power point tracking algorithm, the working state of the charger can be adjusted in real time to make it always work at maximum power, thus improving the charging efficiency.
4. Conclusion
Maximum power point tracking algorithm of photovoltaic power generation is an important technology, which plays a key role in photovoltaic power generation system. This paper introduces two common maximum power point tracking algorithms: P&O algorithm and INC algorithm, and introduces their applications in different application scenarios.
With the advancement of technology and the increasing demand for renewable energy, the maximum power point tracking algorithm will be further improved and optimized. By continuously improving the accuracy and stability of the algorithm, the efficiency and reliability of the photovoltaic power generation system can be further improved.
