Types of inverters used in photovoltaic systems.
1 - Central Inverters: It is characterized by a low cost that makes it used in stations with large capacities, by means of which we have more than one series of panels from which cables exit to the assembly boxes and then to the central reflector, as a single reflector is used for the entire photovoltaic system
2 - String Inverters: In the photovoltaic system, we have a group of panels connected to each other in chains, each chain of which is connected with a reflector, and it is possible that the group of panels is connected with a power optimizer and then to the inverter. This type is used in systems that contain chains of different directions or when there is shading, which gives flexibility in different radiation conditions.
3 - Microinverters: From their size, they gained their name. Small-sized reflectors are installed on the base directly behind the solar panel, or they may be integrated with the panels, depending on the manufacturer. The outputs from all the inverters are then combined to be consumed in different electrical loads.
The difference between power optimizers and microinverters
The power enhancer is a device that is installed behind the photovoltaic panel, or it may be integrated with it as a micro-inverter, but what is the difference between them?
· The power optimizer adjusts the voltage coming out of the board to maintain a constant value, resulting in a continuous voltage, and needs to be connected with an inverter to be converted into alternating, unlike the microinverter, which produces an alternating voltage directly.
· In the system that uses panels with an energy enhancer, if the inverter goes out of service, the production of electrical energy will stop completely, while if a failure occurs in one of the micro-inverters, this will not affect the rest of the system.
Advantages of using photovoltaic panels with microinverters
· In the event that one of the micro-inverters is damaged, the production of electrical energy remains continuous so that when a malfunction occurs, the capacity of the damaged solar panel is lost without affecting the rest of the system by the damage, unlike the system that uses the chain inverter, as the inverter’s failure to service means that the production of electrical energy stops completely.
Each of these inverters is characterized by the fact that it tracks the maximum power point “MPPT” and that it may contain a monitoring device that can record performance measures and errors for each of them and send that data wirelessly to the manufacturer’s server or store it locally. One of the biggest advantages of microinverters is that they allow for the optimization of solar panel performance. Traditional inverters, which are typically installed at a central location, can only optimize the performance of the entire solar array as a whole. This can lead to problems if some panels are shaded or if there is a problem with a single panel, as it can affect the performance of the entire array. With microinverters, each panel is able to operate independently, allowing for maximum performance and efficiency.
Another benefit of microinverters is that they make it easier to monitor and track the performance of each individual panel. This allows for early detection of any problems, such as shading or malfunctioning panels, and can greatly reduce the time and cost of maintenance.
Microinverters also have the advantage of being more reliable than traditional inverters. They have no moving parts and are less likely to fail, which means they require less maintenance and have a longer lifespan.
While microinverters do tend to be more expensive than traditional inverters, the benefits they offer in terms of performance and efficiency can often make up for the added cost. They also make it easier to expand or add to an existing solar array, as each panel can easily be connected to its own microinverter.
Do microinverters improve safety and security in solar systems?
Microinverters improve safety and security factors in solar photovoltaic systems. This is what made it a prerequisite in many countries around the world for the installation of photovoltaic solar systems on the roofs of schools or hospitals. The high safety and security factors are due to the following reasons:
· High safety and fewer electrical losses: The current in the external cables is alternating current.
· Quick Shutdown: In case of an emergency, the system can be quickly and easily shut down.
· Easy to detect and fix errors: thanks to the monitoring of the performance of each board individually and independently of the rest of the boards.
· The possibility of expanding the system easily since the panels are independent of each other.
Disadvantages of using photovoltaic panels with microinverters
· Exorbitant cost: we need a number of microinverters equal to the number of panels used, in addition to the need for more cables.
· Difficult to maintain, as it is located directly behind the board.
· Effect of atmosphere on electronics and their efficiency.
· The efficiency is lower compared to the string inverter.
Despite the low cost of installing panels with power enhancers compared to the cost of panels with micro-inverters, the use of micro-inverters remains better in terms of safety and security, as there is no continuous high voltage on the surface as is the case with other types of inverters, in addition to flexibility in design and ease of monitoring. The performance of the panels, which allows the identification of problems and troubleshooting, and when any failure occurs, the losses are limited to the faulty equipment, and this does not affect the production of the entire system.