Inverters for photovoltaic systems (PV) from specialist wholesalers

A grid-connected inverter is the core of a photovoltaic system. This is also called a photovoltaic system (PV) and produces direct current. However, alternating current is needed to feed it into the public grid and to operate most electrical appliances. The inverter converts the solar power of the photovoltaic system into alternating current.

For grid-connected photovoltaic systems we have PV inverters from the following brand manufacturers in our range: KOSTAL, Fronius, SMA, RCT, SOFAR and FOX ESS. All the devices we offer have maximum efficiency for long-term high yields. This applies to both the single-phase and three-phase inverters, with and without transformers.

Inverter 1
Inverter 2
Kostal
Fronius
Sma Center
Inverter 3

The function of the inverter

The DC voltage of the solar current is characterised by a constant strength and direction. AC voltage, however, is sinusoidal. To convert the DC voltage of the photovoltaic system into AC voltage, a process called "pulse width modulation" is used. In this process, the DC voltage is "chopped" and partially rotated in its direction. The pulses created by the chopping are then averaged and filtered. This is done with the help of complex electronic circuits. The result is an alternating voltage with a frequency of 50 Hz.

What tasks does the unit perform?

The PV inverter is not only used to produce alternating current from solar power. Another important component of the device is the so-called MPP tracking. MPP is the abbreviation for Maximum Power Point. The electrical properties of a photovoltaic system change with the strength and direction of the solar radiation and the temperature. MPP tracking now ensures that the solar system always operates in the optimal range. This is essential for the efficiency of the PV system. The solar energy is never converted 100 % into electricity. A good, common value for efficiency today is 98 % to 99 %.

What types of inverters are there?

There are the following classifications for the units:

  • Single-phase inverter:

    In single-phase devices, the solar energy converted into electricity is transported via a line. Single-phase devices therefore usually have a lower output. On the other hand, fewer components are required, which makes the devices cheaper.

  • Three-phase inverter:

    With three-phase units, the current is transported via three lines. For units with higher power ratings, high-quality, correspondingly expensive power electronics would have to be installed for a single-phase solution. This would be more expensive than the three-phase solution. Therefore, units with power ratings above 5 kW are usually three-phase.

  • Module inverter:

    Here, each module of the PV system has its own solar inverter. Although this is comparatively expensive, it offers advantages. Each module of the PV system can be controlled individually. This is useful in the event of a fault, for example. Since module inverters generally do not produce reactive power, they are only approved for systems with a limited output.

  • String inverter:

    A string is the series connection of several solar modules. String inverters are used for larger photovoltaic systems. They can feed in the power in one or three phases, as they produce both active and reactive power.

  • Central inverter:

    These are units for large commercial photovoltaic systems. More than 12 strings can be switched via them.

  • Hybrid inverter:

    A combination of a PV inverter and a battery inverter. This results in greater power supply security.

  • Battery inverter:

    These inverters are preferably installed in AC coupled systems to be able to charge batteries.

What must be considered when choosing an inverter?

If possible, a photovoltaic system should face south at an inclination of 35°. This gives the best yield of solar electricity. However, the choice of the right solar inverter is also decisive for the performance of the system. The rated power of the solar system can be up to 10 % higher than the rated power of the solar inverter. If it is even higher, part of the solar energy cannot be converted and is therefore lost. It is also important that the maximum DC voltage of the PV system never exceeds the permissible input voltage of the solar rectifier.