Do solar grid connected need frequency converters?

The inverter is an inverter for wind power and photovoltaics. Otherwise, the solar cell power generation is DC, and the power grid is AC, which requires inverter conversion.

It seems that the "grid-connected" solar power generation does not need a "frequency converter"!

But an "inverter" is needed! Because the output of "photovoltaic power generation" is "direct current", it needs to be inverted into "alternating current" in order to be "connected to the grid"!

The electricity generated by solar energy is direct current, and it must be converted into 220V50Hz alternating current to be connected to the grid. At the same time, the condition of being in the same phase must be satisfied. Two conditions are indispensable.

The output of solar power generation is direct current, which can be stored directly in the battery, or it can be converted into 220 volt alternating current through the inverter for various household appliances or integrated into the national grid.

Before installation, please read the installation instructions on the package, and compare whether the size of the LCD protective film is consistent with the size of the screen;

Try to find a dusty environment when installing, this product is composed of three layers of film, and the layer of "(1) hand-torn label is a peelable protective layer, and a layer without labeling is a protective film; Finally, peel off the film (2).

The side of the BenQ computer screen protector that is in contact with the peelable protective layer is attached to the screen surface during installation;

Before installation, be sure to wipe the surface of the LCD screen clean, do not have obvious dirt, especially do not leave particulate matter, there will be bubbles when there are particles of dust;

Since BenQ computer screen protector adopts negative ion electrostatic adsorption technology, it will absorb small dust in the air after removing the peelable protective layer, so we recommend that the peelable protective layer be removed and installed successfully in a short time;

Do not operate too fast when pasting the liquid crystal protective film, and do not tear too fast when tearing off and repasting to prevent the liquid crystal protective film from deforming;

Small bubbles can be squeezed out with a soft cloth after the liquid crystal film is pasted, or it can disappear naturally;

If you want to tear it off after pasting, you can use transparent glue to stick one corner of the protective film and slowly bring it down.

It depends on whether the grid-connected inverter has the function of independent operation in the absence of a power grid. The general grid-connected inverter is a current type, only responsible for sending current to the grid, and the voltage is maintained by the power grid. In the case of losing the power grid, some grid-connected inverters automatically cut off the connection to the grid, convert to voltage type, and generate 220V or 380V voltage to provide to users, this kind of inverter can supply power to the load without being connected to the grid.

If you need an inverter that is not connected to the grid and can carry loads, you can consider an off-grid PV inverter.

It can be connected directly to the load, but this is too wasteful, and the load has no electricity at night and when the weather is bad.

A control system means that any amount of interest or variable within a machine, mechanism or other device can be maintained and changed in the desired way. At the same time, the control system is implemented to achieve a predetermined ideal state for the controlled object. The control system makes the controlled object tend to a certain desired stable state.

An inverter (also known as converter, reverser, or reverse converter, voltage converter) is an electronic device that uses a high-frequency bridge circuit to convert direct current into alternating current, and its purpose is the opposite of that of a rectifier. It converts 12V or 24V DC to 230V, 50Hz AC or other types of AC. It consists of an inverter bridge, control logic, and filter circuitry.

Friendliness. Precautions for solar photovoltaic grid-connected power generation: power quality problems: photovoltaic grid-connected inverters are prone to harmonics, three-phase current imbalance, and output power uncertainty is easy to cause grid voltage fluctuations and flicker, which need to be judged.

The output force of photovoltaic voltage is random and varies greatly, and it does not have inertia, so it is necessary to increase the rotating reserve capacity of the power grid for adjustment; There are also technical problems in various operation control measures, such as power supply reliability index analysis, voltage and reactive power control, electric energy metering and billing, and information interaction with the grid automation system. For a large number of distributed photovoltaic power sources connected to the distribution network, the original radiation collision distribution network has become a multi-power supply structure, and protection and automation devices need to be installed or replaced; The problem of self-sufficiency caused by photovoltaic power supply is not just like pure and ordinary islands, and it is necessary to install a variety of effective protections.

It is necessary to pay attention to the orientation of the components, which must be to the south, and it is best to have a certain inclination; Pay attention to occlusion, this must be clear enough; Modules of the same matrix need to have similar currents, otherwise the power generation efficiency of the modules will be affected after series connection. In humid areas, modules are prone to PID phenomenon, mainly negative electrodes, which will lead to a gradual decrease in module power. This will affect the power generation effect of the entire matrix (please ignore the household system, which mainly occurs in large-scale ground power stations); It is not possible to build a photovoltaic power station near the airway airport, and the reflected light from the electric panels will affect the take-off and landing of aircraft. If it is a distributed power station, not all roofs are suitable for installing solar power stations, and some roofs are not load-bearing, so it is recommended to conduct an on-site inspection first.

High reliability is required. At present, photovoltaic power generation systems are mainly used in remote areas, and many power stations are unattended and maintained, which requires the inverter to have a reasonable circuit structure, strict component screening, and requires the inverter to have various protection functions, such as input DC polarity reverse protection, rental brother AC output short circuit protection, overheating, overload protection, etc. In medium and large-capacity photovoltaic ridge-bending power generation systems, the output of the inverter power supply should be a sine wave with less distortion.

This is due to the fact that in the medium and large capacity system, if the square wave power supply is adopted, the output will contain more harmonic components, and the higher harmonics will produce additional losses, and the load of many photovoltaic power generation systems is communication or instrumentation equipment, which has higher requirements for the quality of the power grid.

The connection between the power generation system and the power grid can be divided into two categories: independent photovoltaic system and grid-connected photovoltaic system. After years of development, photovoltaic power generation is currently a relatively mature and reliable technology, and has gradually developed from an independent system in the past to a large-scale grid-connected direction. However, the most significant disadvantage of photovoltaic power generation at present is the high cost, which is currently about 20 times that of coal power and about 10 times that of wind power.

According to the development roadmap of the United States, Japan, and Europe, it is expected that with technological advancement, improvement of conversion efficiency, and expansion of market size, the cost of photovoltaic power generation may be close to the current cost of wind power by around 2030. In short, solar photovoltaic power generation is currently costly, but the industrialization foundation is good, and it has the technical, cost and environmental advantages of becoming a strategic energy source around 2030, and can become an important energy source around 2050.