The difference between low frequency and high frequency

The low frequency inverter converts the DC power into low frequency low-voltage AC power firstly, then boosts into 220V 50Hz AC power for the load through the low frequency transformer. Its advantage is that the structure is simple, and various protection functions can be realized at lower voltages. Because there is a low frequency transformer between the inverter and load, the inverter runs stably, reliably, with strong overload capacity and shock resistance, and can suppress the high-order harmonic elements in the waveform. However, low frequency inverter is heavy and expensive, and it efficiency is relatively low. The rated efficiency of the small low frequency inverter produced at the current production level does not exceed 90% generally. At the same time, the iron loss of the low frequency inverter is basically unchanged when it operates under full load and light load, so the no-load loss is large and the efficiency is low in light load working status. 

The high frequency inverter converts low-voltage direct current into high-frequency low-voltage alternating current through high frequency DC/DC conversion technology firstly. After the high-frequency transformer is boosted, it is rectified by the high-frequency rectifier filter circuit to a high-voltage direct current, usually above 300V high-voltage direct current; finally, the 220V low frequency alternating current is obtained for the load through the low frequency inverter circuit. Since the high-frequency inverter power supply adopts the high-frequency magnetic core material with small volume and light weight, the power density of the circuit is greatly improved, so that the no-load loss of the inverter is small, and the inverter efficiency is improved. Usually, the high-frequency inverter power supply for small and medium-sized PVS, its peak conversion efficiency is more than 90%.