Three-phase current detection method and circuit

Abstract

The invention relates to the field of circuits, and discloses a three-phase current detection method, and the method comprises the following steps: acquiring bus voltage in a load starting process inreal time; performing fast Fourier transform on the bus voltage, and extracting a plurality of actual signal components with preset frequencies; and judging whether the three-phase current is open-phase or not according to the actual signal component. The invention also discloses a three-phase current detection circuit. The three-phase current detection method and the three-phase current detectioncircuit provided by the embodiment of the invention have the advantages of detecting whether the input power supply is open-phase before the load is started and preventing the load from running underthe open-phase power supply.

Description

technical field [0001] The invention relates to the field of circuits, in particular to a three-phase current detection method and a circuit. Background technique [0002] Three-phase AC power input phase loss or wrong phase may lead to damage or abnormal operation of load electrical equipment. It is generally required to configure a phase sequence relay on the power input side to detect whether the input power is abnormal in real time, so as to shut down in time to ensure the safety of personal equipment. For example, in the elevator control system, the lack of phase operation of the inverter may cause damage to the rectifier bridge of the inverter, large fluctuations in the bus voltage, and abnormal operation of the elevator. In order to avoid these problems, the usual method is to equip the elevator control cabinet with a phase Sequence relays are used to detect whether the input phase is missing, but the use of phase sequence relays not only occupies the space of the con...

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Problems solved by technology

For example, in the elevator control system, the lack of phase operation of the inverter may cause damage to the rectifier bridge of the inverter, large fluctuations in the bus voltage, and abnormal operation of the elevator. In order to avoid these problems, the usual method is to equip the elevator control cabinet with a phase Sequence relays are used to detect whether the input phase is missing, but the use of phase sequence relays not only occupies the space of the control cabinet but also increases the cost. On the other hand, the phase sequence relays may lose their proper functions due to damage during use. Cause the inverter to run under phase loss current

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