In the photovoltaic grid-connected system, components, inverters and power grids constitute the electrical system.
The output power of the grid-connected inverter has no special requirement for AC overload, because the output power of the inverter will not exceed the module power basically.
In the photovoltaic off-grid system, components, batteries, inverters, loads constitute the electrical system, the output power of the inverter, is determined by the load, some perceptual load, such as air conditioning, water pump, etc., the motor inside, starting power is rated power 3-5 times, so off-grid inverter overloading special requirements.
Both capacitance and inductance are energy storage elements.
The difference is that capacitance stores electric energy in the form of electric field.
The larger the capacitance is, the more electric energy is stored.
Inductance, on the other hand, stores energy in the form of a magnetic field.
The greater the permeability of the core of an inductor, the greater the amount of inductance, and the more energy it can store.
Power frequency isolation transformer refers to the transformer with power frequency (50HZ). Both the primary and secondary transformers have inductors, and the filter inductors in the inverter can store certain electric energy. When the inductance flows through the current, the magnetic field will exist. When the magnetic field of the current passes through the core, the current magnetic field will break the equilibrium state of the "magnetic domain", making the "domain" tend to the direction of the external magnetic field at the same time, thus causing the core to present the external magnetic field at this time. And the core magnetic field from nothing to the process, in fact, is the process of inductive storage of magnetic field.
Photovoltaic off-grid system, the output power is determined by the load.
When the motor and other inductive load start, a very large current is needed in a short time, and this energy, photovoltaic can not provide, the battery can not provide, lithium battery short time if overload output, will cause an explosion.
However, the capacitance, inductance and transformer in the inverter can store energy and can be amplified several times in a short time without damage to the output.