1. What is a solar inverter
Unlike energy storage inverter, the photovoltaic inverter is one of the important system balances (BOS) in the photovoltaic array system, which can be used with general AC power supply equipment. Solar inverters have special functions with photovoltaic arrays, such as maximum power point tracking and island protection.
It is a device that converts the direct current generated by solar modules into alternating current available to residents. Home solar inverter can convert the variable DC voltage generated by photovoltaic solar panels into mains frequency AC inverters.
It can be fed back into commercial transmission systems or used by off-grid grids. Therefore, the efficiency of power generation conversion is a priority issue for purchasing home solar inverters.
2. How to choose the most suitable home solar inverter
As photovoltaics enter more homes, more and more home users will have a question before installing photovoltaics. What kind of home solar inverter should be selected? To install home photovoltaics, the following 5 aspects are the aspects you should consider:
● Maximize revenue
At present, the use of high-power and high-current components in Chinese households has become a mainstream trend, so household users should first consider inverters adapted to high-current components, which have higher conversion efficiency and lower cost. In addition, there are several important indicator parameters to compare:
- Inverter efficiency
The maximum efficiency and MPPT efficiency of home solar inverters are important indicators to consider inverter power generation, the higher the efficiency, the stronger the power generation.
- DC operating voltage range
The wider the DC operating voltage range, the earlier the start and stop, the longer the power generation time, the higher the power generation.
- MPPT tracking technology accuracy
MPPT tracking technology should have high accuracy, fast dynamic response speed, can adapt to sharp changes in light, and improve power generation efficiency.
● Flexible adaptation
The environment of household power stations is relatively complex, and problems such as the end of rural power grids and power consumption will cause alarms such as AC overvoltage and undervoltage of home solar inverters.
Home solar inverters need to have weak grid support, a wide range of grid voltage adaptation, overvoltage reduction, reactive power compensation and other functions to reduce fault alarms. The number of MPPTs is also an important indicator to consider. Multichannel MPPT configuration can be flexibly configured for different orientations, different roofs, different specifications of components and other factors.
● Simple installation
The small, lightweight model is easier to install. At the same time, you should choose a home solar inverter that is set up in advance before leaving the factory. After installing it in the user's home, it can be used when it is powered on, saving debugging time and making it more convenient.
● Safe and stable
Since many home solar inverters are installed outdoors, IP waterproof and dustproof rating is a non-negligible protection indicator. It can effectively protect the inverter in the adverse climate environment to avoid harmful effects, and the inverter with IP65 and above should be selected to ensure the normal operation of the inverter in our home energy storage.
In terms of protection functions, in addition to DC switching, input overvoltage protection, AC short circuit protection, AC output overcurrent protection, insulation impedance protection and other necessary functions, there are also 3 functions that are very important:
- DC arc pulling intelligent detection
It can accurately distinguish the arc pull signal, quickly shut down, avoid fire, and protect the safety of users.
- Fault recording function
Observe and record voltage and current waveforms on the AC side of the inverter in real time to quickly locate problems.
- Intelligent scanning and diagnostics
It can accurately locate string faults and proactively find problems. Multiple guarantees, stable operation of the power station, users can truly rest assured.
● Intelligent management
In today's digital era, intelligent devices can provide users with more convenience. Home solar inverter brands equipped with intelligent management platforms can bring great convenience to users in power station management:
- You can monitor the power station with your smartphone, and you can view the operation data of the power station anytime and anywhere, and keep abreast of the status of the power station.
- Sellers can find problems and analyze the cause of faults through remote diagnosis. Provide solutions to solve problems remotely in a timely manner.
3. Common installation methods of home solar inverter
● Photovoltaic bracket
The installation scheme of distributed common ground projects can be installed under a string of nearby components, and the equipment can be directly fixed to the column by fixed bracket installation or hoop installation. This scheme requires attention to the strength of the bracket and the height of the home solar inverter from the ground to prevent placing the equipment too low on rainy days.
This form of installation is mainly used in large industrial and commercial plants. Due to the empty roof, there is nowhere to hang the home solar inverter. Considering the cost of reducing cable costs, home solar inverters generally require self-made mounting brackets.
The PV inverter is suspended on a self-made bracket, which needs to consider the load-bearing and fixed form of the inverter and the ability to resist typhoons in coastal areas. As we all know, the ambient temperature rises, and the life of electronic devices is halved.
For this installation form of inverter long-term exposure to the scorching sun, the internal temperature of the home solar inverter will be greatly increased, seriously affecting the life of the key components of the inverter.
In order to protect the internal components of the inverter, the inverter will run derating, and even if the temperature is too high to cause the inverter temperature to fail, it is recommended that the photovoltaic inverter add a sunshade to avoid scorching sun exposure.
Home solar inverters are installed vertically on flat roofs to create shadows and usually with lithium battery. Therefore, when the equipment is installed, the components should be installed outside the shadow range of the inverter as much as possible to avoid shadow obscuration of the components.
● Wall (wall mounted)
Common home distributed project rooftop power station installation form. With this form of installation, the home solar inverter is exposed to as little sun as possible. Specific installation requirements are as follows:
- The installation of the machine should have a suitable height from the ground in order to observe and read the LED display.
- When installed outdoors, the photovoltaic inverter should be equipped with a rainproof sunscreen canopy to avoid direct sunlight and rain immersion.
- The inverter should not be exposed directly to the sun or other heat sources.
- Leave enough space for it to be installed with the mobile inverter.
- There must be enough load-bearing, which is more than 1.5 times the weight of a home solar inverter.
- The heat dissipation duct of the photovoltaic inverter is the lower air inlet, the upper air outlet, the inverter should be installed vertically, and it is strictly forbidden to install horizontally or upside down.
- Home solar inverters must be placed in a space with air circulation.
- The inverter is divided into forced air cooling and natural heat dissipation, the inverter itself is a heating source.
- All heat must be dissipated on time and can not be placed in a closed space, otherwise the temperature will rise higher and higher.
4. Installation precautions for home solar inverter
First check whether the home solar inverter has been damaged during transportation. When choosing a photovoltaic inverter installation site, it should be ensured that there is no interference from other power electronic equipment around.
Before making an electrical connection, be sure to cover the photovoltaic panels with opaque materials or disconnect the DC side circuit breaker. If exposed to sunlight, PV inverter arrays will generate dangerous voltages. All installation operations must be done by professional technicians only.
Cables used in photovoltaic power generation systems must be firmly connected, well insulated and of suitable specifications. All electrical installation steps must meet local and national electrical standards. The PV inverter can only be connected to the grid after obtaining local permission and having all electrical connections completed by professional technicians.
Before carrying out any PV inverter repair work, the electrical connection between the inverter and the grid should be disconnected. Then disconnect the DC side electrical connection. Wait at least 5 minutes until the internal components are discharged before repair. Any fault that will affect the safety performance of the PV inverter must be eliminated immediately before the inverter can be turned on again.
The capacity of home solar inverters is generally about 5~10KW. Therefore, when choosing a home solar inverter, the price difference of the inverter is small, and the overall price will also be different.
However, the power generation income over the entire life cycle varies greatly, so from the perspective of long-term income and system stability, it is recommended to use a home solar inverter model with high conversion efficiency. The stability of the internal components of the inverter will directly affect the quality and operating efficiency. Choosing high-quality components will greatly reduce the maintenance cost of home PV inverters.