Micro inverter product knowledge encyclopedia

In the design of solar photovoltaic grid connection, the role of the inverter is very important. The inverter can convert solar energy into DC power, and then form single-phase AC power suitable for various equipment through inversion.

Inverter Classification

Based on different uses at present, inverters can be divided into two types, one is an independent power supply, and the other is a grid-connected power supply.

And according to the waveform modulation method, it can be divided into square wave inverter, ladder wave inverter, sine wave inverter and combined three-phase inverter.

For inverters used in grid-connected systems, they can be divided into transformer-type inverters and non-transformer-type inverters according to the presence or absence of transformers.

The background of the emergence of the new framework

At present, the most widely used photovoltaic system in the market is the centralized inverter. The so-called centralized inverter is to connect a solar photovoltaic cell in series to achieve a high-voltage direct current, which is then converted into alternating current through the inverter. However, in a photovoltaic power station, solar photovoltaic cell components, local shadows, different inclination angles and orientations, dirt, different aging degrees, small cracks, and different temperatures of different photovoltaic panels can easily cause system mismatch and cause output efficiency to drop. The disadvantages of the inverter lead to a significant reduction in the overall output power, so this has also become a difficult problem for the centralized inverter to solve.

In order to solve this problem, a new architecture called "micro-inverter" and "micro-converter" has emerged in recent years. Each solar cell module is equipped with a micro inverter power supply, and the output power of each module is optimized to maximize the overall output power. Even if some panels are affected by shadows, dust coverage, etc., the inverter power optimizer can still track the best local MPP (Maximum Power Point), recovering more than 57% of lost power generation. At the same time, the power optimizer converts the input voltage/current to a different output voltage/current to maximize the energy transfer in the system.

Microinverter Definition

The micro-inverter technology proposes to directly integrate the inverter with a single photovoltaic module, and equip each photovoltaic module with an inverter module with AC-DC conversion function and maximum power point tracking function to directly convert the electric energy emitted by the photovoltaic module The converted AC energy is used by AC loads or transmitted to the grid.

When one of the battery panels does not work well, only this one will be affected. The other photovoltaic panels will all be running at their best, making the overall system more efficient and producing more electricity. In practical applications, if the string inverter fails, it will cause several kilowatts of battery panels to fail to function, while the impact caused by the failure of the micro-inverter is quite small.

Several advantages of micro-inverter

1. Try to increase the power generation of each inverter module and track the maximum power. Since the maximum power point of a single module is tracked, the power generation of the photovoltaic system can be greatly increased by 25%.

2. Adjust the voltage and current of each row of photoelectric panels until they are all in balance to avoid system mismatch.

3. In addition, each module has a monitoring function, which reduces the maintenance cost of the system and makes the operation more stable and reliable.

4. The configuration is flexible. In the household market, the size of photovoltaic cells can be installed according to the user's financial resources.

5. No high-voltage electricity, safer, simple and faster installation, low maintenance and installation costs, and less dependence on installation service providers, so that the solar power generation system can be DIY by users.

6. The cost is comparable to or even lower than that of centralized inverters.