Open phase detection circuit for multi-pulse rectifier circuit

Abstract

The invention discloses an open phase detection circuit for a multi-pulse rectifier circuit, which comprises a voltage screening module, an optocoupler module and an open phase detection module, wherein the voltage screening module comprises a line voltage input terminal and a transient suppression diode; the optocoupler module comprises a two-way optical coupler; the open phase detection module comprises an auxiliary power supply, a capacitor and an open phase detection terminal; the line voltage input terminal is correspondingly connected with the two-way optical coupler through the transient suppression diode; the two-way optical coupler and the auxiliary power supply are correspondingly connected with the capacitor; and the capacitor is correspondingly connected with the open phase detection terminal. The circuit form is simple; the open phase detection accuracy is high; and through adjusting the breakdown voltage of the transient suppression diode, screening on a line voltage peakvalue is realized, and the circuit is applicable to open phase detection for a general circuit (open phase in a suspended state) and particularly applicable to open phase detection for a multi-pulserectifier circuit (coupling of line voltage by open phase and other phases) with an autotransformer.

Description

technical field [0001] The invention relates to phase loss detection, in particular to a phase loss detection circuit of a multi-pulse rectifier circuit. Background technique [0002] Airborne AC electrical equipment often adopts a three-phase three-wire system for power supply. When there is a phase loss in the three-phase input, in order to ensure a balanced power supply, the electrical equipment should have a phase loss detection function and be able to take corresponding protective measures. The current lack of phase detection technology for three-phase three-wire power supply is based on the fact that the lack of a phase presents a floating characteristic and utilizes the principle that a loop cannot be formed between it and the other two phases. When the electrical equipment adopts a multi-pulse rectifier circuit with an autotransformer, the missing phase will no longer show the characteristics of being suspended, but will couple a higher line voltage between the trans...

AI Technical Summary

Problems solved by technology

For example, under the airborne 115V AC power supply, the peak value of the normal line voltage is 280V. When a multi-pulse rectifier circuit with a certain type of autotransformer is used, when a certain phase input is missing, the line coupled between it and the other two phases The peak voltage can reach 200V. In this case, the existing phase loss detection technology cannot accurately detect the phase loss state

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