The core difference between power frequency and high frequency on-line UPS lies in whether there is a built-in power frequency isolation transformer, which directly determines the circuit topology and working frequency of the two, and finally leads to a significant difference in volume, efficiency, anti-interference ability and on-load characteristics.
First, the core structure differences
1. Power frequency online UPS
Core features: It must be equipped with a power frequency isolation transformer (50/60Hz), which is bulky and heavy.
Typical topology:
Mains input → input filter → SCR/IGBT rectifier → DC bus → IGBT inverter → power frequency isolation transformer → output filter → load.
Rectifier: **SCR (silicon controlled rectifier) * * rectifier is used traditionally, and IGBT rectifier is also available.
Inverter: IGBT inverter, working frequency is 50Hz.
Key components: output isolation transformer. Provide electrical isolation, voltage rise and fall, suppress zero ground voltage and enhance impact resistance.
2. High-frequency online UPS
Core features: No power frequency transformer, high frequency switching technology (IGBT+PWM) to achieve voltage conversion.
Typical topology:
Mains input → input filter → IGBT high frequency rectifier (PFC) → DC bus → high frequency inverter → output filter → load.
Rectifier: IGBT high-frequency rectification, built-in **PFC (power factor correction) * * circuit.
Inverter: IGBT high-frequency inverter, the working frequency is usually **>20kHz**.
Key components: high-frequency DC-DC boost circuit and high-frequency filter inductor.
III. Summary of Core Differences
Essential difference: power frequency machine depends on "transformer" and high frequency machine depends on "high frequency switch".
Structural impact: the power frequency machine is reliable, anti-manufacturing, bulky and inefficient because of the transformer; High-frequency machine is efficient, lightweight, energy-saving and weak anti-interference because it has no transformer.
Selection watershed:
Power frequency: industrial environment, high power, inductive load such as motor/water pump, bad power grid, strong isolation and high reliability.
Choose high frequency: data center, computer room, server, office equipment, energy saving, space saving and low cost.
