How To Choose Solar Inverter

Time：[2017-3-30]     Views：1899

Solar inverters

Because of the diversity of the building,will inevitably lead to the diversity of solar panels installed,in order to make solar energy conversion efficiency while taking into account the highest architectural appearance,which requires us to diversify the inverter,the best way to achieve a solar conversion.Now the world more prevalent solar inverter way,central inverters,string inverters,multi-string inverters and inverter module,inverter will now be analyzed using several occasions.

Central inverters

Central inverters for general use and large-scale photovoltaic power plants (> 10kW) systems,many parallel PV strings are connected to the same central inverters DC input,the general power of three-phase IGBT power module,the use of smaller power field-effect transistors,while the DSP switch controller to improve the quality of the produced energy,making it very close to the sine wave current.The biggest feature is the system's high power and low cost.But the influence of PV strings match and partial shading,resulting in efficiency and power capacity of the entire PV system.At the same time the entire PV power generation system reliability by the poor state of a photovoltaic cell groups working affected.The latest research is the use of space vector modulation control,as well as the development of new inverter topology connection,to obtain a high efficiency under partial load conditions.

On SolarMax (Shohreh • Mike) central inverter,interface box can be attached to a photovoltaic array,each string of PV windsurfing string monitoring,such as a string which is not working properly,the system will put this information to the remote controller,and can be stopped by a bunch of these remote control,so that will not be a bunch of photovoltaic string of failures and reduce the impact of work and energy output of the entire PV system.

String inverters

String inverters are now on the international market has become the most popular inverter.String inverters are based on each PV string (1kW-5kW) through an inverter,to the DC terminals have a maximum power modular concept based on the peak tracker,the AC side in parallel and network.Many large-scale photovoltaic power plants using string inverters.The advantage is not the difference between the modules and the string affect shaders,while reducing the optimum operating point of PV modules.

In the case of the inverter mismatch,thereby increasing the generation capacity.Technically these advantages not only reduces system cost and increases the reliability of the system.Meanwhile,in the string between the introduction-the concept of "master-slave",so that in the system in a single string of energy can not work a single inverter case,several groups of PV strings together,so that one or several working to produce more power.The latest concept of several inverters to each other to form a "team" instead of "master - slave" concept,making the reliability of the system one step further.Currently,transformerless string inverters accounted for a dominant position.

Multi-string inverters

Multi-string inverters are to take advantage of centralized inverters and string inverters,to avoid its shortcomings,can be applied to several kilowatts of photovoltaic power stations.In the multi-string inverters,and it includes different individual peak power tracking and DC to DC converters,these DC by a common DC to AC inverter into alternating current,grid to grid.PV strings of different ratings(eg:different power ratings,each string a different number of components,the components of different manufacturers,etc),different sizes or different techniques of PV modules,strings in different directions(eg:East,South and West),a different angle or shading,can be attached to a common inverter,while each string are working at their respective maximum peak power on.

At the same time,reduce the length of the DC cable will affect shader string and losses due to differences between the groups between strings caused minimized.

Inverter assembly

Each component of the inverter is connected to a PV inverter,and each component has a separate maximum peak power tracking,so that the components fit better with the inverter.Typically used for 50W to 400W photovoltaic power stations,lower than the overall efficiency of string inverters.Because it is at the parallel exchange,which increases the complexity of the AC side of the connection,and difficult to maintain.Another need to be addressed is how to be more effective with the power grid,the simplest way is through the network directly and ordinary AC outlet so that you can reduce installation costs and equipment,but often safety standards around the grid may not allow To do so,the company may oppose the power generation unit and the average home user is directly connected to an ordinary socket.Another relevant factor is the need for security and the use of isolation transformers(high or low frequency),or allow the use of transformerless inverters.The inverter is the most widely used in glass curtain wall.