Photovoltaic grid-connected solar power generator rely on solar battery panel pack,with the electronics characteristic of semiconductor material,converting solar power to be electricity power. Photovoltaic grid-connected solar power generation system (PV system) is via photovoltaic array to convert solar radiation power after getting through high frequency direct-current to be high voltage direct-current,to transform high voltage sine alternating current after the operation of power inverter.

Grid-connected power generation system is the grid-connected solar power generation system to connect with ordinary electric grid,to afford this obligation of electricity supply together.When having solar lighting,the power inverter would convert the direct-current which was produced by PV system to be sine alternating current which can be supplied for AC load,then transform the rest power electricity to electric grid,or transform all of power electricity to grid. All of electricity consumption of load would be provided by electric grid when not having solar lighting.

As directly transforming power electricity to electric grid,the storage battery of photovoltaic independent system is completely replaced by the electric grid which is a part of photovoltaic grid-connected system.It can make the most of the electric energy which is generated by PV array because of removing the storage battery to get rid of the process of storing and discharging,which can reduce the loss of energy and the cost of system. But PV system need have special grid-connected power inverter,to guarantee the output electricity power being able to meet this standard of voltage,frequency,and others that the electric grid require.At the same time,power inverter also control the max power pot track(MPPT) of PV system and wave shape and power of grid-connected current,which can balance the power that is transformed by electric grid and the max power electricity that is generated by PV array. Usually,this system can use electric supply parallel with solar PV system as the power source of local alternating current load,which reduce the rate of outage in whole of system.Besides,photovoltaic grid-connected solar power generation system can regulate the public electric grid. It is the only way which must be passed to enter large scale commercial use for grid-connected solar power generator,namely,it is connecting PV system into normal electric grid,to realize connective generator together.

1.To compare the independent photovoltaic grid-connected solar power generator station,connected with electric grid can bring many advantages for PV system as below:
1). It saves the storage battery pack as power energy storage.
2).With the progress of power inverter manufacturing,the stability and reliability of power inverter will be more advanced.
3).PV array can operate at the max power point all the time,electric grid incorporate all of electricity power that solar radiation generate,which improves the efficiency of solar power generator.
4).Electric grid get the power electricity, the distributed allocation PV system can provide power energy for local users,which relieve the transforming and dispatching burden of electric grid. 5).The PV array can perfect match with building,it not only can generate electricity,but also become building and decoration stuff.

2.To compare off-grid solar power generation system,grid-connected solar power generation system have below advantages:
1). To utilize clean and renewable energy,solar radiation power,to generate electricity,not to consume Carbon fossil energy which is non-renewable energy and limited resources,not to discharge greenhouse gases and pollution stuff,to be harmonious with ecological environment,which accords with the strategy of economic and social sustainable development.
2). All of electricity power that PV generates transform into electric grid,to treat electric grid as storage installation.It can easily buy electricity power from urban electricity if the solar power energy is not enough when to use more high load.While the rest power electricity can sell to urban grid if it have surplus electricity when the use is small.This system don’t need storage battery pack under attaching with electric grid,which enlarges the flexibility of application range,to improve the working efficiency of this system and to reduce its cost.
3).The PV battery array can be perfect matched with building,it not only can generate electricity,but also become building and decoration stuff,which makes these material resource be maked the most use and perform its many kinds of function.It not only can reduce the cost of building,but also improve the technology of building,to achieve more “ sales point”.
4).Distributed establishing,generating and to provide electricity power at the near grid, to make it be more flexible to enter or withdraw electric grid.It can enhance the resistance ability of war and disaster,besides,it can improve the load balance of power generator system and reduce the wastage of circuit.

Even if photovoltaic grid-connected solar power generation system have so many advantages,it still don’t have more large development because of huge investment,long establishing time and high scale area covering. With the technology progress,PV system will be popular in near future,because its many advantages are human’s motive to make study.