What are the important technical parameters of off-grid inverters

System Voltage

It is the voltage of the battery pack, the input voltage of the off-grid inverter and the output voltage of the controller are consistent.

Output Power

There are two expressions of the output power of the off-grid inverter, one is in the power representation, the unit is VA, which refers to the UPS mark, and the actual output active power needs to be multiplied by the power factor, such as a 500VA off-grid inverter , the power factor is 0.8, and the actual output active power is 400W, that is to say, it can drive 400W resistive loads, such as lamps, induction cookers, etc. The second is active power representation, the unit is W, such as 5000W off-grid inverter, the actual output active power is 5000W.

Peak Power

In the photovoltaic off-grid system, components, batteries, inverters, and loads constitute the electrical system. The output power of the inverter is determined by the load. For some inductive loads, such as air conditioners and water pumps, the starting power of the motor inside is 3-5 times the rated power, so the off-grid inverter has special requirements for overload. The peak power is the overload capacity of the off-grid inverter.

The inverter provides the load with starting energy, part of which comes from the battery or photovoltaic modules, and the excess part is provided by the energy storage elements inside the inverter—capacitors and inductors. Capacitors and inductors are both energy storage components. The difference is that capacitors store electrical energy in the form of an electric field. The larger the capacity of the capacitor, the more electricity it stores. An inductor stores energy in the form of a magnetic field. The greater the permeability of the inductor core, the greater the inductance, and the more energy it can store.

Conversion Efficiency

The conversion efficiency of the off-grid system includes two aspects. One is the efficiency of the machine itself. The circuit of the off-grid inverter is complex and needs to undergo multi-level conversion, so the overall efficiency is slightly lower than that of the grid-connected inverter, generally between 80-90%. , The higher the power of the inverter, the higher the efficiency, the higher the efficiency of high frequency isolation than the power frequency isolation, the higher the system voltage is, the higher the efficiency is. The second is the charging and discharging efficiency of the battery. This is related to the type of the battery. When the photovoltaic power generation is synchronized with the load power consumption, the photovoltaic power can be directly supplied to the load without battery conversion.

Switching Time

The off-grid system has loads and has three modes: photovoltaic, battery, and mains. When the battery energy is insufficient and switches to the mains mode, there is a switching time. Some off-grid inverters use electronic switches to switch, and the time is within 10 milliseconds , the desktop computer will not shut down, and the lights will not flicker. Some off-grid inverters use relay switching, the time may exceed 20 milliseconds, and the desktop computer may shut down or restart.