What is the difference between a high frequency inverter and a power frequency inverter?

1) In terms of reliability, power frequency machines are better than high frequency machines. Power frequency machines 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 machine 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, the high-frequency machine is better than the industrial frequency machine. The high-frequency machine uses a microprocessor as the processing and control center, and burns the complicated hardware analog circuits into the microprocessor, and uses software programs. To control the operation of the UPS. 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 that have less stringent requirements on reliability. Because of this, many manufacturers of small and medium power UPS have generally introduced high-frequency machines.
(3) In terms of the load's requirements for the zero-ground voltage, the power frequency machine is better than the high-frequency machine. The high-power three-phase high-frequency machine zero line will introduce a rectifier and serve as the neutral point of the positive and negative bus bars. This structure is inevitable The ground causes the high frequency harmonics of the rectifier and inverter to be coupled to the neutral line, which raises the zero-ground voltage, and causes the zero-ground voltage of the load terminal to rise. It is difficult to meet the requirements of IBM, HP and other server manufacturers for the zero-ground voltage of less than 1V. In addition, when the mains and generators are switched, the high-frequency machine often has to switch to the bypass due to the missing zero line, which may cause a major failure of load flashing under certain working conditions. The power frequency machine does not need the neutral line to participate in the work because of the rectifier. When the neutral line is disconnected, the UPS can maintain normal power supply.