Should RVs choose power frequency inverters or high frequency inverters?

Consumers are always entangled between the industrial frequency inverter and the high frequency inverter when purchasing the RV inverter. What is the difference between the two?

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.

Features of power frequency inverter:

1. The cost of industrial frequency inverters is higher than that of high frequency inverters at low power.

2. The weight and volume of the industrial frequency inverter are larger than the high frequency inverter of the same power.

3. The efficiency of the power frequency inverter is a little lower than that of the high frequency inverter, and the iron loss is basically unchanged when operating under full load and light load. Therefore, the no-load loss of the power frequency inverter running under light load is relatively large. .

4. The reliability of the power frequency inverter is higher than that of the high frequency inverter, and it is not easy to break.

5. The load capacity of the industrial frequency inverter, especially the impact load capacity, is better than that of the high frequency inverter, and it can suppress the higher harmonic components in the waveform.

6. The structure of the power frequency inverter is relatively simple, and the overload and short circuit protection is easier to manufacture than the 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 and 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.

Features of high frequency inverter:

1. The no-load loss of the high frequency inverter is very small, so the inverter efficiency is high.

2. The high-frequency inverter is small in size and light in weight.

3. The high-frequency inverter has low no-load load, cannot be connected to a full-load inductive load, and has relatively poor overload capacity.

Performance comparison between power frequency inverter and high frequency inverter:

1. In terms of reliability, power frequency inverters are better than high frequency inverters

Power frequency inverters use thyristor (SCR) rectifiers. After more than half a century of development and innovation, this technology has been very mature, and its ability to withstand current shocks is very strong. Since the SCR is a semi-controlled device, there will be no faults such as through and false triggering. In contrast, although the IGBT high-frequency rectifier used in the high-frequency inverter has a higher switching frequency, the IGBT has a strict voltage and current working area when it is working, and its impact resistance is low. Therefore, in terms of overall reliability, IGBT rectifiers are lower than SCR rectifiers.

2. In terms of environmental adaptability, high frequency inverters are better than power frequency inverters

The high-frequency inverter uses the microprocessor as the processing control center, burns the complicated hardware simulation circuit in the microprocessor, and controls the operation of the UPS in the form of a software program. Therefore, the volume and weight are significantly reduced, the noise is also small, and the impact on space and environment is small. Therefore, it is more suitable for office places with less stringent requirements on reliability.

3. In terms of load requirements for zero-ground voltage, industrial frequency inverters are better than high frequency inverters

The zero line of the high-power three-phase high-frequency inverter will introduce the rectifier and serve as the neutral point of the positive and negative buses. This structure inevitably causes the high frequency harmonics of the rectifier and inverter to be coupled on the zero line, raising the zero ground Voltage, causing the zero-ground voltage of the load terminal to rise, it is difficult to meet the requirements of the server manufacturers such as IBM and HP for the zero-ground voltage of less than 1V. In addition, when the mains and generators are switched, high-frequency inverters often have to switch to bypass due to the missing of the neutral line, which may cause major faults such as load flashing under certain operating conditions.