18/03/2025
Solar Power System.
Advantages, Disadvantages and Performance Comparison of High-frequency Inverter and Power Frequency Inverter
Inverter is a device that converts DC into AC to meet the needs of AC load. Inverters can be divided into high-frequency inverter and power frequency inverter. So what are the characteristics of power frequency inverter and high-frequency inverter?
1. High-frequency inverter
High-frequency inverter uses high-frequency DC/AC conversion technology to convert low-voltage DC into high-frequency low-voltage AC, and then after high-frequency transformer boost, it is rectified into high-voltage DC usually above 300V through high-frequency rectifier filter circuit, and finally 220V power frequency AC is obtained through power frequency inverter circuit for load use.
Advantages and Disadvantages of High-frequency Inverter: High-frequency inverter uses small and light high-frequency magnetic core materials, which greatly improves the power density of the circuit, makes the no-load loss of the inverter power supply very small, and improves the inverter efficiency. Usually the peak conversion efficiency of high-frequency inverter reaches more than 90%. However, it also has significant disadvantages. High-frequency inverters cannot be connected to fully loaded inductive loads, and their overload capacity is poor.
2. Power frequency inverter
The power frequency inverter is a DC/AC converter designed with high-frequency pulse width modulation technology and microcomputer control technology to convert the DC power supply of the battery pack into an AC power supply with stable output voltage and frequency.
Advantages and disadvantages of power frequency inverters: Its characteristics are that the structure is relatively simple, and the protection functions can be realized in a relatively low voltage. Because there is a power frequency transformer between the inverter power supply and the load, the power frequency inverter runs smoothly and reliably, has strong overload capacity and impact resistance, and can suppress high-order harmonic components in the waveform. However, the power frequency transformer is also relatively heavy and expensive, and its efficiency is relatively low. At this stage, the load efficiency of small power frequency inverters on the market is usually not higher than 90%. In addition, because the iron loss of the power frequency transformer is basically unchanged when running under full load and light load, the no-load loss is large when running under light load, and the efficiency is also low.
3. Performance comparison between power frequency inverter and high frequency inverter
1. In terms of reliability, power frequency inverter is better than high frequency inverter
Power frequency inverter uses thyristor (SCR) rectifier. After more than half a century of development and innovation, this technology has become very mature and has strong current impact resistance. Since SCR is a semi-controlled device, there will be no faults such as direct-through and false triggering. In comparison, although the IGBT high-frequency rectifier used in high-frequency inverter has a higher switching frequency, IGBT has a strict voltage and current working area when working, and its impact resistance is low. Therefore, in terms of overall reliability, IGBT rectifier is lower than SCR rectifier.
2. In terms of environmental adaptability, high frequency inverter is better than power frequency inverter
High frequency inverter uses microprocessor as processing control center, burns complex hardware simulation circuits into microprocessor, and controls the operation of UPS in the form of 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 that do not require too much reliability.
3. In terms of the load's requirements for neutral voltage, the industrial frequency inverter is better than the high-frequency inverter
The neutral 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 busbars. This structure will inevitably cause the high-frequency harmonics of the rectifier and the inverter to couple on the neutral line, raising the neutral voltage, causing the load-side neutral voltage to rise, which is difficult to meet the site requirements of server manufacturers such as IBM and HP for a neutral voltage less than 1V. In addition, when switching between the mains and the generator, the high-frequency inverter often has to switch to bypass operation due to the lack of the neutral line, which may cause a major fault of load flashing under certain working conditions.
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