How to boost productivity of solar systems? German innovative ShadeFix solutions in Armenia

Inverters are one of the most important elements of solar installations, and their quality is directly proportional to the performance and safety of the solar installation.

As a leading technical company in solar energy, OHM ENERGY constantly follows the development of solar technologies in the world and tries to bring the already polished international experience of many years to Armenia. Such as, for example, the use of the proprietary SMA ShadeFix feature from world market leader SMA Solar Technology, a German heavy-duty inverter manufacturer, in this area, which provides the highest possible performance even when parts of entire panels are shaded.

The use of this function has been implemented in Armenia by OHM ENERGY since late 2020, and many companies and individuals have already purchased this type of solar converters.

The inverters are the single and central node of the electronics in the solar system. If we had to describe the operation of the entire solar system, we would see that the solar panels are responsible for obtaining electricity from the sun's rays, while the inverters convert the direct current (DC) produced by the panels into alternating current (AC).

Moreover, the electricity coming from the grid inverters directly feeds the internal consumers of the house or facility (refrigerator, TV, pumps, etc.), after which the excess part of the generated electricity is sent to the distribution networks. So choosing a quality inverter will not only lead to high performance, but will also ensure long-term uninterrupted operation of your electrical equipment, keeping losses to a minimum.

When installing solar installations, the efficiency of the entire system and important safety guarantees also depend on the right choice of inverters. The problems caused by poor-quality inverters are manifold. One of the most common problems is that inverters output a modified sinusoidal current instead of a pure sinusoidal current (Fig. 1).

(Fig.1) The difference between pure sinusoidal current and modified sinusoidal current at the output of inverters.

The presence of modified sinusoidal current at the output of an inverter can disable devices powered by this source.

The key examples of problems that arise are:

• the creation of excessive noise in electrical equipment,
• excessive heating of motors and transformers, which leads to power loss,
• the violation of the digital clock and synchronization circuits, up to two times,
• damage to power supplies of sensitive electronic equipment, etc.
  
  

Another important component of inverter operation is the MPP (Maximum Power Point) seeker.  The operation of modern inverters is based on this technology. The essence of the MPP finder is to find the maximum power point of the solar plant at which the solar system will have the highest performance.

However, not all inverters have the level of development of the MPP detector, which can provide maximum power generation due to environmental influences. The most frequent problems are possible shadows falling on the solar panels, in which case the performance of the entire system can be significantly reduced. Typically, photovoltaic systems are placed where they can convert the greatest amount of sunlight into electricity. However, it is not always possible to prevent poles, chimneys, trees and other obstructions that can cast shadows on the solar panels. This reduces energy efficiency and increases the payback period of the system.

To understand the depth of the question, let's look at two examples: the performance of the MPP tracker in shadowless and shadowed conditions.

To discuss the first example, let's look at the process of finding the maximum power point in shadowless conditions.

We will see the relationship between power and voltage (Fig. 2), which are the main parameters for measuring solar systems. These units of measurement construct the power curve of the solar system (Fig. 2). In each solar inverter, the MPP finder determines the optimum power point at which the solar system operates at maximum power. The maximum point on the power curve is called the maximum power point or MPP, and the corresponding voltage is called the MPP voltage.

(Fig. 2) Solar power curve in the absence of shadow.

Under shadow conditions, the solar power curve changes (Fig. 3).  In this case, the solar plant has several maxima, but conventional MPP detectors cannot find all these points because they only scan the closest range of the current point. Therefore, because of the shadows, the performance of the solar plant can be much lower than it could actually produce.

(Fig. 3) Power curve of the solar system in the presence of shade.

This does not limit the functionality of inverters, but for a complete general understanding it is enough to add that quality inverters must contain electrical safety features. OHM Energy succeeded in becoming the official partner of the German SMA Solar Technology in Armenia, producing solar inverters. Solar inverter manufacturer SMA has revolutionized the world of inverters by combining a unique design with an installation method that significantly reduces installation time and covers all target groups, ensuring a minimal payback period. With over 1600 patents, SMA has been able to anticipate the future and find ways to develop solar PV installations over its 40-year history.

With its exclusive ShadeFix system, SMA, a renewable energy enthusiast, is the only company in the world to produce an inverter that neutralizes the reduced efficiency of the entire installation due to shading.

Fig 4.  Patented SMA Shadefix System

A) standard inverter operation,

Fig 4. B) applying SMA Shadefix system when one panel is shaded

Unlike circuit standard inverters, SMA ShadeFix provides maximum performance by allowing unshaded panels to operate at maximum power even when one panel is shaded, while with standard inverters even one panel is shaded, the optimal voltage of the entire circuit drops.

The speed and accuracy of the SMA search algorithm is unparalleled, which manages to keep power loss to an absolute minimum.  Thanks to the patented SMA algorithm, Shadefix is the only MPP search solution that consistently delivers the best possible performance for solar systems. The features described above make inverters very important in solar systems. To all this, it is only worth adding what types of solar inverters exist, the differences in which, however, do not change the approaches to quality assessment. As for the types of solar inverters, they are network, stand-alone and hybrid, which in turn can be single-phase or three-phase (depending on the type of electrical network).

To summarize, inverters are one of the most important elements of solar installations, and their quality is directly proportional to the performance and safety of the solar installation.