What is the difference between string inverter and central inverter?

The PV inverter is a converter device that converts DC electrical energy into AC electrical energy. Photovoltaic inverters are used in solar photovoltaic power generation systems. They are an important component of photovoltaic systems. The photovoltaic inverter is composed of a boost circuit and an inverter bridge circuit. The boost circuit boosts the DC voltage to the DC voltage required at the output of the inverter, and the inverter bridge circuit converts the boosted DC voltage into fixed frequency AC voltage.

Types of photovoltaic inverters:

According to the working principle, photovoltaic inverters can be divided into centralized inverters, string inverters and micro inverters.

The centralized inverter:

The centralized inverter is to connect parallel photovoltaic groups in series to the DC input of the same centralized inverter, and after tracking the maximum power peak value, it is connected to the grid through the inverter. The unit capacity is usually above 500kW, which is mainly suitable for large-scale photovoltaic power stations on the ground with uniform illumination, etc.

The string inverter:

The string inverter is to track the maximum power peak of 1-4 sets of photovoltaic strings individually, and merge them into the AC grid after being inverted. The unit capacity is generally below 100kW, which is mainly suitable for distributed power generation systems;

The string inverter adopts modular design, which can realize the optimization of distributed MPPT. A power station system using string inverters usually converts the DC current generated by the components through the inverter for DC to AC conversion, and then merges into the AC grid after converging, step-up transformation, and AC power distribution. Compared with the centralized inverter, the string inverter adopts a modular design and has multiple MPPT; the number of photovoltaic string inputs connected to each MPPT is less, usually 2-6 groups, which can be distributed MPPT optimization. Due to the small number of access points, when a single component fails, it will only affect the power generation of the corresponding module of the string, which ensures the power generation efficiency of the overall photovoltaic system and solves the problem of mismatch in centralized photovoltaic power plants.

String MPPT has a wide voltage range, which can increase the power generation time and output of the system. The MPPT voltage range of string inverters is relatively wide, usually 200V-1000V, with good adjustability. In the case of insufficient sunlight or the weather is not conducive to power generation, the overall voltage of photovoltaic modules will be low, and the wider MPPT voltage range can achieve low input voltage coverage, thereby ensuring the power generation time of the system and increasing the overall power generation.

The following are string inverters from IEETek Company:

Micro inverter:

The micro inverter can track the maximum power peak value of each photovoltaic module individually, and merge it into the AC grid after being inverted. The unit capacity is generally below 1kW, which is mainly suitable for distributed households and small and medium-sized industrial and home rooftop power stations.

The micro-inverter can perform MPPT control on a single component, and the power generation efficiency and power generation level are high. Different from other inverters, the micro-inverter is integrated with each photovoltaic module and can perform Maximum Power Peak Tracking (MPPT) control for a single module, thereby greatly improving the overall power generation efficiency and output of the system. At the same time, the micro-inverter has the characteristics of small size and light weight. No additional place is needed, which greatly enhances the convenience of installation, and is mainly suitable for small and medium-sized power station projects such as households.

The input port voltage for micro inverter is low, it is a safe voltage, and it is not easy to draw an arc, which is safer for wooden houses.

The following are IEETek Company’s micro inverters:

What is the difference between a portable power station and a generator?

The main function of the portable power station and generator is to solve the emergency power supply for outdoor electricity demand and indoor power outage usage.

Generators and portable power stations can solve the outdoor electricity demand of equipment and instruments. You may ask, what is the difference between a portable power station and a generator?

IEETek Company has a lot of professional experience in portable power stations and inverters. We will introduce their differences:

For Principles:

The generator is powered by gas or other fuel. It is a mechanical device that converts other forms of energy into electrical energy. It converts the energy produced by the combustion of gasoline or diesel into mechanical energy and transmits it to the generator, which then converts it into electrical energy.

The portable power station is a multifunctional portable energy storage power supply with the built-in lithium-ion battery, which can store electric energy and has an AC output. The product is light weight, high capacity, high power. It is easy to carry, and it can be used indoors or outdoors. You can choose city grid charging or solar charging according to different usage conditions.

For portability:

Generators need to be used with gas or other fuel. It is not suitable for outdoor travel. The generator emits exhaust gas during operation, which is very bad for the environment. It consumes some fuel and produces relatively loud noise.

The portable power station has the characteristics of light weight, high capacity and high power, and it is easy to carry. The portable UPS can be used as a DC or AC power supply when used in mountainous areas, pastoral areas, field surveys, traveling and leisure without electricity, or in cars or ships.

IEE Singo series are 1008Wh and 672Wh. It is with large capacity options. Backup power products are suitable for indoor power outages, picnics, and emergency situations.

The charging method can be charged by solar photovoltaic panels, car cigarette lighter, or select grid charging.

IEE Singo products have built-in AC fast charging technology and apply the core technology of the inverter. The charging efficiency is as high as 800W, and the battery can be fully charged in 1.5 hours. This saves you charging time. Most products in the market are built-in adapters, and the charging efficiency is slow and bulky.

The IEE Singo series portable power station uses LiFePO4 Cells batteries. It is safer. When in use, the noise is less than 30db. It could be your good choice.

By Team

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