Most people have heard of solar energy and some solar products, such as solar street lamps, solar water heaters, solar cells, etc., but they do not know what the solar inverter is. In fact, the solar inverter has been widely used in our lives. It is an important component of the solar AC power generation system, and its main function is to convert the DC power generated by the solar panel into the AC power used by household appliances. How to choose solar inverter for household solar energy system? I will introduce it from several aspects.
Data source: China Commercial Industry Research Institute
With LCD display. The solar inverter with LCD display is intuitive and convenient, which is suitable for querying real-time power generation when there is no mobile phone. Mobile phones are used to monitor the operation of power stations, which can be queried at any time, and thousands or even tens of thousands of power stations can be managed uniformly. The two-way monitoring system can provide active services, so that we can find problems, early warning of faults, remote diagnosis and processing of problems.
Low noise. The household solar inverter is installed indoors. If there is noise during operation, it will bring inconvenience to your life. Most of the noise of the inverter comes from fans and inductors, so the inverter should be fan free design, and there is no fan inside or outside, so as to eliminate the noise source as much as possible. Alternatively, the inductor can be filled with glue as a whole and put into an aluminum case separately to reduce the current and vibration sound of the inductor.
It shall have sufficient rated output capacity and load capacity. The total power of the battery panel in the solar power generation system should not exceed 80% of the inverter power, and the total power of the load connected to the inverter should not exceed 80% of the inverter power. The inverter needs to be selected according to the type of load. Therefore, before selecting the inverter, please first determine whether there are inductive loads, such as motors, refrigerators, air conditioners, washing machines, high-power water pumps, etc. When starting, Its instantaneous power may be 5-6 times of its rated power, at this time, the inverter will bear a large transient surge. For such systems, the rated capacity of the inverter shall have sufficient margin to ensure reliable starting of the load. The high-performance inverter can achieve continuous full load starting for many times without damaging power devices.
It has good over-current protection and short-circuit protection functions. During the normal operation of the solar power generation system, it is normal for the power supply system to have over-current or short circuit due to load fault, personnel misoperation and external interference. The inverter is most sensitive to the over-current and short circuit of external circuit, and is the weak link in the solar power generation system. Therefore, when selecting inverter, it is required to have a good self-protection function against overcurrent and short circuit.
Select according to the inverter output waveform. Waveforms of inverters are mainly divided into three categories: square wave inverter, modified wave inverter and pure sine wave inverter. The square wave inverter outputs square wave AC with poor quality, and its positive and negative peaks almost occur at the same time, which will damage the load and the inverter itself. Moreover, the load capacity of square wave inverter is poor, which is only about half of the rated power, and it can not carry inductive load. Modified sine wave inverter uses PWM pulse width modulation to generate modified wave output. Due to about 20% harmonic distortion, it can not carry inductive loads such as air conditioner, but can carry resistive loads such as electric lamps. The modified sine wave inverter adopts non isolated coupling circuit, with simple components and high efficiency. The pure sine wave inverter is designed with isolated coupling circuit. The circuit is complex and the cost is high. It can connect any common electrical equipment (including televisions, liquid crystal displays, especially inductive loads such as refrigerators) without interference, and has little damage to the load and inverter itself. Therefore, although the cost of the pure sine wave inverter is higher than that of the square wave inverter and the modified sine wave inverter, We still suggest to choose pure sine wave inverter as far as possible.
Image source: Baidu Pictures
Easy maintenance. After several years of operation, the solar inverter is prone to failure due to part failure, which is a normal phenomenon. Therefore, in addition to the good after-sales service system, the manufacturer is required to have good maintainability in terms of inverter production process, structure and component selection. For example, the damaged components have sufficient spare parts or are easy to buy, and the components have good interchangeability; In terms of process structure, components are easy to disassemble and replace. In this way, even if the solar inverter fails, it can quickly return to normal.
