What are the differences between high frequency inverters and power frequency inverters

An inverter is a device that converts direct current (DC) into alternating current (AC) to meet the power demand of AC loads. According to the topology, inverters can be divided into high frequency inverters and power frequency inverters.

High frequency inverter

The high-frequency inverter first uses high-frequency DC/DC conversion technology to invert low-voltage direct current into high-frequency low-voltage alternating current; then, after being boosted by a high-frequency transformer, it is rectified by a high-frequency rectifier filter circuit to usually above 300V High-voltage direct current, and finally through the power frequency inverter circuit to obtain 220V power frequency alternating current for the load.

Because the high-frequency inverter adopts a small, light-weight high-frequency magnetic core material, the power density of the circuit is greatly improved, so that the no-load loss of the inverter power supply is small, and the inverter efficiency is improved. Generally, high-frequency inverters used in small and medium-sized PVS have a peak conversion efficiency of more than 90%.

Power frequency inverter

The power frequency inverter first inverts the DC power into a power frequency low-voltage AC power, and then boosts it into a 220V, 50Hz AC power for the load through a power frequency transformer.

Its advantage is that the structure is simple, and various protection functions can be realized under lower voltage. Because there is a power frequency transformer between the inverter power supply and the load, the inverter operates stably, reliably, has strong overload capacity and shock resistance, and can suppress high-order harmonic components in the waveform. However, the power frequency transformer also has the problem of being bulky and expensive, and its efficiency is relatively low.

The small power frequency inverter manufactured according to the current level, its rated load efficiency generally does not exceed 90%. At the same time, the iron loss of the power frequency transformer is basically unchanged when the power frequency transformer is running under full load and light load, so it can run under light load. The no-load loss is larger and the efficiency is lower.