With the development of Cell and PV module technology, various technologies such as half cut cell, shingling module, bi-facial module, PERC, etc. are superimposed on each other. The output power and current of a single module have increased significantly. This brings higher requirements to inverters.
1.High-Power Modules requiring Higher Current Adaptability of Inverters
The Imp of PV modules was around 8A in the past, so the maximum input current of the inverter was generally around 9-10A. At present, Imp of 350-400W high-power modules has exceeded 10A that is necessary to select an inverter with a maximum 12A input current or higher to meet high power PV module.
The following table shows the parameters of several kinds of high-power modules which used in the market. We can see that the Imp of the 370W module reaches 10.86A. We must ensure the maximum input current of the inverter to exceed the Imp of the PV module.
2.As the power of a single module increases, the number of input strings of the inverter can be appropriately reduced.
With the increase in the power of PV modules, the power of each string will also increase. Under the same capacity ratio, the number of Input Strings per MPPT will decrease.
The maximum input current of Renac R3 Note Series 4-15K three-phase inverter is 12.5A, which can meet the needs of high-power PV modules.
Taking 370W modules as an example to configure 4kW, 5kW, 6kW, 8kW, 10kW systems respectively. The key parameters of the inverters are as follows:
When we configure a solar system, we can consider DC oversize. DC oversize concept is widely adopted in solar system design. Currently, PV power plants worldwide are already oversized on average between 120% and 150%. One of the main reasons to oversize the DC generator is that the theoretical peak power of the modules is often not achieved in reality. In some areas where with insu fficient irradiance, positive oversizing (increase PV capacity to extend system AC full-load hours) is a good option. A good oversize design could both help the system close to full activation and keep system under healthy condition, which makes your investment worthwhile.
The recommended configuration is as follows:
As long as the maximum open circuit voltage of the string and the maximum DC current are within the tolerance of the machine, the inverter can work connecting with the grid.
1.Maximum DC current of the string is 10.86A, which is less than 12.5A.
2.Maximum open circuit voltage of the string within the inverter’s MPPT range.
Summary
With the continuous improvement of module’s power, inverter manufacturers need to consider the compatibility of inverters and modules. In the near future, the 500W+ PV modules with a higher current are likely to become the mainstream of the market. Renac is achieving progress with innovation and technology and will launch the latest products to match with higher Power PV module.