Device for removing current wave distortion in AC magnetic field under start and stop

Abstract

The invention discloses a device for removing current wave distortion in an AC magnetic field under start and stop. The device comprises a distribution network power supply, a self-coupling transformer, a two-way silicon controlled, a current riser and a sensing coil which are sequentially connected; a phase acquiring module is connected to the output end of the self-coupling transformer; a voltage acquiring module is connected to the output end of the self-coupling transformer; the phase acquiring module and the voltage acquiring module are connected in parallel; the output ends of the phase acquiring module and the voltage acquiring module are connected to a logic control module; an external control module for receiving an external instruction is connected to the logic control module; a silicon controlled driving module for amplifying a silicon controlled control signal is arranged between the logic control module and a control pole of the two-way silicon controlled; an auxiliary power supply is connected to the silicon controlled driving module. According to the device, the silicon controlled for connecting and disconnecting output current can connect and disconnect AC sinusoidal wave current in the range from 0 to 180 degrees; the waveform of the current is started and stopped in 0 or 180 degrees, so that the current is avoided large variable during connecting and disconnecting.

Description

technical field [0001] The invention relates to the technical field of power frequency magnetic field immunity test, in particular to a device for eliminating current wave distortion in an AC magnetic field when starting and stopping. Background technique [0002] The existing power frequency magnetic field generating device conforming to IEC61000-4-8 and GB / T 17626.8 is random in phase when the AC current injected into the induction coil is turned on and off. If it is not turned on and off near 0 degrees and 180 degrees, and the load induction coil impedance of the current source is very small, there will be the following problems: [0003] 1. A large di / dt change rate, which is much higher than the di / dt change rate under power frequency, the strength of the power frequency magnetic field interference test depends on this change rate, which is equivalent to the beginning and end of the test An additional magnetic field strength much larger than the normal test is generate...

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Problems solved by technology

[0005] 3. Because of the inductive load of the inductive coil, the sharp rise and fall of current changes will cause overshoot / undershoot, which will cause waveform distortion and increase the severity of the test.

[0006] 4. Due to the existence of small parasitic capacitance, it will cause high-frequency oscillation of the current waveform under transient excitation

[0007] 5. If a mechanical switch is used to control on-off, electric sparks and electric arcs will be generated, resulting in instantaneous and instantaneous strong electromagnetic field radiation, which increases additional interference sources that are not related to the test, and the life of the mechanical switch is reduced due to electric sparks and electric arcs. short

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