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String Inverter vs Central Inverter: What’s The Best?

When we talk about types of inverters for solar PV systems, we often hear about central inverters and string inverters. String Inverter vs Central Inverter: What’s The Best? Firstly, Let’s take a look at how they work.

What is a string inverter

String inverters is a device that converts the DC power generated by solar panels into the AC power we use. It has an intelligent modular design where each PV string is connected to the DC input of a designated inverter. These inverters are modularly grouped together and the AC outputs of all the inverters are connected in parallel to convert the DC power to AC power.

String-Inverters

What is a solar central inverter

In this technique, several PV strings are connected in parallel to the DC input of the same inverter. For high power systems, three-phase IGBT power modules are typically used, while field effect transistors are used for lower power systems. The solar central inverter utilizes a DSP converter controller to improve the quality of the output power so that it is close to a sinusoidal current. Solar central inverter is mainly used in large-scale PV power systems, usually with a power of 10 kw or more.

Central-Inverters

So, which is better, solar central inverter or string inverters? Next, let’s analyze the advantages and disadvantages of each of them.

Advantages of string inverters

  • Modularized design, not affected by the difference between PV strings and shadow.
  • Wide MPPT voltage range, can generate power even in bad weather.
  • Small size and light weight, easy to install, no need for specialized equipment.
  • Low power consumption, small fault impact, easy replacement and maintenance.

Disadvantages of string inverters

  • More electronic components, slightly lower reliability.
  • Not suitable for high altitude areas and outdoor installation.
  • Slightly poorer electrical safety.
  • The number of inverters is large, the total failure rate will increase, and the system monitoring is difficult.
  • If more than 40 inverters are in parallel, the total harmonics will be superimposed, and it is difficult to suppress.
  • when multiple machines are in parallel, the zero voltage crossing function, reactive power regulation, active power regulation and other functions are difficult to achieve.

Advantages of solar central inverter

  • Small number of inverters, easy to manage;
  • Small number of inverter components, high reliability;
  • Less harmonic content, less DC component, high power quality;
  • Inverter high integration, high power density, low cost;
  • The inverter has complete protection functions and high safety of the power station;
  • Power factor adjustment function and low voltage crossing function, good grid adjustability.

Disadvantages of solar central inverter

  • Narrow MPPT voltage range, short generation time.
  • Installation requires a dedicated machine room and equipment.
  • Affects the whole system when the failure rate is high.

Different applications

  • Solar central inverter are usually used for large power systems such as large plants, desert power stations and ground power stations.
  • String inverters are mainly used for small and medium-sized rooftop PV power generation systems and small ground power stations.
application of solar central inverter
home solar system_application of string inverters

The above is the advantages and disadvantages of solar central inverter and string inverters comparison, string inverter scompared to solar central inverter, whether in the failure rate, system security or operation and maintenance costs are more dominant, the system reliability is better, can ensure the long-term safety of the power station, reliable operation, which is the buyers of large-scale photovoltaic system more and more prefer string PV inverter rather than centralized PV This is also the reason why buyers of large-scale PV systems increasingly prefer string inverters to solar central inverter.

When it comes to reliable solar string inverters, look no further than Guangdong Techfine Electronic Co.,Ltd, one of the leading solar string inverter manufacturers. With a reputation for quality and innovation, we provide cutting-edge solutions tailored to meet your specific needs. Trust Guangdong Techfine Electronic Co.,Ltd for exceptional performance and durability in your solar energy projects.

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