Research Paper on the Current Status of Photovoltaic Inverters

How intelligent is a PV inverter system?

Although various intelligent technologies have been used in a PV inverter system, the intelligence of the whole system is still at a rather low level. The intelligent methods are mainly utilized together with the traditional controllers to improve the system control speed and reliability.

What is the control performance of PV inverters?

The control performance of PV inverters determines the system’s stability and reliability. Conventional control is the foundation for intelligent optimization of grid-connected PV systems. Therefore, a brief overview of these typical controls should be given to lay the theoretical foundation of further contents.

What is the power rating of a PV inverter?

Another important requirement of the inverter is to protect against overload conditions. Therefore, when designing a system, the power rating of the inverter should normally be greater than 90% of the maximum power of the PV module , .

Are PV inverters voltage regulated?

In the modern day, the PV inverters are being developed under the interconnection standards such as IEEE 1547, which do not allow for voltage regulations . However, a majority of manufacturers of PV inverters tend to enhance their products with reactive power absorbing or injecting capabilities without exceeding their voltage ratings.

How do PV inverters control stability?

The control performance and stability of inverters severely affect the PV system, and lots of works have explored how to analyze and improve PV inverters’ control stability . In general, PV inverters’ control can be typically divided into constant power control, constant voltage and frequency control, droop control, etc. .

Why do solar PV inverters use a lower capacitance value?

Since capacitor value directly depends on the maximum power, most of the inverters use electrolytic capacitors parallel to the PV module. This element reduces the lifetime and increases the cost of the photovoltaic system , . Thus, the solar PV inverter desires to use reduced capacitance value.