Conventional energy is non renewable, and modern industrial development requires a large amount of energy. Therefore, new energy has become a key development object. Among many new energy sources, solar energy is highly favored. It not only meets the needs of sustainable development, but also has excellent clean and environmentally friendly performance. To leverage the role of solar energy, it is necessary to leverage the role of natural energy and build new photovoltaic stations to provide people with the electricity they need for production and daily life.
1. Photovoltaic grid connected power generation inverter technology
For the photovoltaic grid connected inverter of solar energy, the photovoltaic inverter is an important component of the series photovoltaic array module and the power grid. Its main function is to control the photovoltaic array module and strengthen the role of the maximum power point in the current of the power grid. Generally speaking, in the process of applying photovoltaic grid connected power generation inverter equipment, it should be divided into three types based on the different application methods and scope: firstly, centralized photovoltaic inverters serving large power stations; Secondly, photovoltaic inverters serving component branches; Finally, the communication module is composed of photovoltaic modules.
For centralized photovoltaic inverters, they are often applied to large photovoltaic power plants and digital signal processors are used to better improve grid connected waveforms. The main reason for applying this photovoltaic inverter is because it has high efficiency and requires less investment. However, sometimes, some photovoltaic modules cannot accept sunlight, resulting in mismatched components and photovoltaic inverters, While affecting the reliability of photovoltaic power stations, it is also not conducive to the normal operation of photovoltaic power stations. However, branch grid connected photovoltaic inverters and component photovoltaic inverters do not encounter these situations and have become the most widely used systems for a time.
2. Photovoltaic grid connection technology
The so-called photovoltaic grid connected photovoltaic inverter technology is actually passive inverter technology, which is mostly independent of the power grid system. With the reduction of energy supply, environmental protection issues are becoming increasingly prominent, and the application range of renewable energy power generation systems is also expanding, especially the application of grid connected power generation systems, which not only reduces cost, but also reduces unnecessary losses, increases the service life of batteries, and gradually improves environmental quality. Usually, photovoltaic power generation systems are often applied in areas with low or insufficient electricity, mainly to provide residents with the electricity they need for daily life. With the development of society, the application of grid connected power generation technology is gradually expanding, which is of great significance for promoting the development of solar photovoltaic power generation.
During the operation of photovoltaic power grid connection, the main components include the output voltage of the photovoltaic inverter, grid voltage, resistance, and series inductance. To ensure consistent feedback power factors, it is necessary to strengthen feedback, ensure consistency between feedback current and phase, and use grid voltage as a basic reference. For photovoltaic grid connected power generation systems, it is necessary to control the phase of the power grid and appropriately reduce its frequency. By doing so, the photovoltaic inverter can be controlled to ensure that the current and voltage remain at the same position in both phase and frequency. This is also the key to achieving synchronous phase locking. This not only reduces the impact on the equipment, but also prolongs the equipment’s service life, Avoid equipment damage. Therefore, in this process, the signal processor produced by TI enterprise should be applied, appropriately reducing its size, reducing power consumption, and improving its reliability. Only in this way can it control the PWM signal well and form a phase-locked loop. In the process of applying the phase-locked loop, the signal and frequency should be determined, the phase should be implemented, the role of the phase-locked loop should be played, and the signal output and control should be completed under the influence of this technology.
In the process of outputting the signal, a frequency multiplier can be used to achieve the integer and fraction of the frequency multiplier, and determine the difference between the two. Especially, the application of loop filters can not only reduce low-pass characteristics, but also reduce the adverse effects of voltage signals and high-frequency signals, and complete the transformation under the influence of voltage and frequency. This has become a very important component of phase locking. If special circumstances arise, it is necessary to properly control the frequency multiplier to ensure the integrity of the output signal and input signal, and obtain necessary phase locking. In general, there are two types of phase locking: one is analog phase locking, and the other is digital phase locking. Among these locked phases, they can be divided into three indicators based on their performance, namely phase locking range, speed, and stability [3]. For traditional analog phase-locked circuits, their circuit structure is relatively complex and often requires parameter adjustment. Temperature also has high fluidity and lacks a certain degree of accuracy. In response to this situation, digital phase-locked circuits need to be applied to compensate for the shortcomings of traditional phase-locked circuits. This not only facilitates control, but also promotes device upgrades. At the same time, online modifications can be completed to improve reliability, It is also beneficial for maintenance and meets the needs of modern technological development.
3. Photovoltaic inverter technology
For photovoltaic power generation systems, the most obvious drawback is that they require a large amount of capital investment in the initial stage and have high cost requirements. Therefore, it is necessary to strengthen photovoltaic performance, reduce cost costs, and lay the foundation for photovoltaic conversion. At the same time, it is also necessary to reduce the losses caused by photovoltaic power generation and enhance operational efficiency. Only in this way can reasonable configuration and selection of appropriate equipment be achieved.
From this, it can be seen that photovoltaic inverters have become the main equipment for achieving photovoltaic grid connected power generation. Therefore, it is necessary to strengthen power generation efficiency and reduce investment costs. For photovoltaic grid connected power generation systems, their main components are array modules, control equipment, and photovoltaic inverters. Among them, photovoltaic inverters are key components that connect the other two together and are the key to strengthening control.
To ensure that the photovoltaic grid connected inverter can be connected to the power grid, it is necessary to prioritize the power quality of the power grid and reduce the pollution caused by the photovoltaic grid connected system. This requires the photovoltaic inverter to be able to display the most authentic sine wave. Generally, the most significant impact on waveform distortion is the number of times the photovoltaic inverter switch is used. Therefore, in this process, High speed DSP processors should be applied to enhance the switching performance of grid connected photovoltaic inverters. At the same time, in the process of designing photovoltaic inverters, it is necessary to minimize their size and improve their reliability, especially for photovoltaic systems applied in households. The photovoltaic inverters should be installed indoors or on walls, which determines that their volume and quality are limited. In addition, to ensure high utilization, the overall reliability of the machine should be appropriately enhanced, and the service life of solar cells should be controlled at least 20 years, In this way, the service life of the supporting equipment can be well controlled, ensuring that it is always in a healthy operating state.
To ensure the safe and stable operation of photovoltaic inverters, SPWM technology can be applied to photovoltaic inverters to control voltage and current well. For SPWM, with PWM control technology, its main function is to adjust the pulse width in order to obtain favorable waveforms. Generally speaking, SPWM can be divided into two types of modulation, one is unipolar and the other is bipolar. The phases of the bipolar waveform are always in a complementary state, which is commonly known as bipolar control. In addition, in the process of designing photovoltaic inverter circuits, it is necessary to strengthen circuit protection, ensure that the output AC power is higher than the grid voltage, and design the maximum wattage of the output current. Once a situation above 6000 W is found, the system should automatically stop working immediately, reducing unnecessary losses in this way to lay the foundation for promoting economic development. This is also the most important work to ensure the safe operation of photovoltaic inverters.
4. Conclusion
The rapid development of the economy has driven technological progress, and people’s demand for electricity is also increasing. Therefore, the number of solar photovoltaic power generation equipment is also constantly increasing. In order to optimize photovoltaic power generation systems and ensure that photovoltaic inverter technology for grid connected power generation can play a practical role, it is necessary to innovate on the basis of existing technology and design suitable photovoltaic inverter methods, Only in this way can we lay the foundation for the further development of photovoltaic inverter technology in photovoltaic power grids.