A pfc rectifier and uninterruptible power supply

Abstract

The invention provides a PFC rectifier and an uninterrupted power source and aims to solve a problem of electromagnetic interference caused by high frequency jump of the potential of an electrode of a DC power source connected with a first rectification tube generated between the potential of a zero wire of an AC power source and the potential of a bus output end when a UPS of a single cell set in the prior art working in a cell mode carries out energy storage for a first bus capacitor. The PFC rectifier comprises a PFC rectification circuit and a first switch circuit, a connection point of two bus capacitors of the PFC rectification circuit is connected with a connection point of two switch tubes in the PFC rectification circuit through the first switch circuit, when the PFC rectifier working in the cell mode carries out energy storage for the first bus capacitor in the PFC rectification circuit, the first switch circuit is switched off in a PFC inductance energy storage process in the PFC rectification circuit, and the first switch circuit is switched on in a PFC inductance energy release process in the PFC rectification circuit.

Description

technical field [0001] The invention relates to the technical field of power electronics, in particular to a PFC rectifier and an uninterruptible power supply. Background technique [0002] The power factor correction (PFC, Power Factor Correction) rectification circuit in the online uninterruptible power supply (UPS, Uninterruptible Power Supply) is designed to share some components with the AC / DC converter and the DC / DC converter as much as possible, so as to reduce cost purposes. The single-inductor front-end solution, that is, the solution of adding a PFC inductor at the input end of the DC / DC converter can reduce the cost as much as possible, but most of the uninterruptible power supply topologies using the single-inductor front-end solution have the problem of electromagnetic interference . [0003] Figure 1a In the shown single-phase PFC rectifier circuit using a single battery pack, in the battery mode, the switch K1 is connected to the positive pole of the batter...

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Problems solved by technology

[0008] That is to say, Figure 1b When the single-phase PFC rectifier circuit using a single-battery pack is in operation, the potential of the positive pole of the battery pack DC will jump at high frequency between the potential of the neutral line N of the AC power supply AC and the potential of the positive bus BUS+. Capacitor C3 (the ground capacitance of the negative pole of the battery pack DC) and capacitor C4 (the ground capacitance of the positive pole of the battery pack DC) form a strong high-frequency common-mode current, which forms electromagnetic interference

[0009] In summary, the existing PFC rectifier circuit using a single battery pack operates in battery mode, and stores energy in the bus capacitor connected to the freewheeling tube connected to one electrode of the DC power supply (i.e. Figure 1a in the negative bus capacitor C2 or Figure 1b When the positive bus capacitor C1) in the DC power supply, the potential of the electrode of the DC power supply jumps at a high frequency between the potential of the neutral line of the AC power supply and the potential of the bus connected to the freewheeling tube connected to the electrode of the DC power supply, this A strong high-frequency common-mode current will be formed on the positive-to-ground capacitance of the DC power supply and the negative-to-ground capacitance of the battery pack, thereby forming electromagnetic interference

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