Remote numerical control soft starter for AC power supply, and control method thereof

Abstract

The invention discloses a remote numerical control soft starter for an AC power supply. The remote numerical control soft starter comprises a zero crossing detection circuit, a control circuit and a power switch circuit. An input end of the zero crossing detection circuit is connected with an AC power supply phase line input and a null line input, and is used for detecting a zero point position ofan AC sine wave voltage on the AC power supply phase line input, and transmitting the detected zero point position to the control circuit in the form of a zero crossing detection pulse signal. The control circuit is connected with the power switch circuit and is used for starting timing according to a rising edge of the zero crossing detection pulse signal from the zero crossing detection circuitwhen an external enable signal is in an enable state, outputting a silicon controlled starting pulse to the power switch circuit when the timing reaches a timing value, and gradually rising the voltage output by the power switch circuit when the count value is gradually decreased. When the count value is decreased to 0, the control circuit continuously outputs high level signals to the power switch circuit, so that the power switch circuit is in a continuous turned-on state, and the soft start process is completed.

Description

technical field [0001] The invention belongs to the field of single-phase or three-phase AC power supply, and more specifically relates to a remote numerically controlled soft starter for AC power supply and a control method thereof. Background technique [0002] Usually, single-phase or three-phase AC power is connected to the load through the power switch. When the power switch is turned on, the instantaneous current injected into the load is usually much greater than the steady-state operating current, that is, a surge current is generated. The surge current will not only make the Damage to AC switches, fuses, EMI filters, etc. will also cause interference to the grid power supply, triggering the power protection equipment to turn on, resulting in power outages, or interfering with the normal operation of other equipment. At the moment when the power is turned on, the inrush current generated by the load exceeds the normal operating current by dozens of times, and the inr...

AI Technical Summary

Problems solved by technology

[0005] Aiming at the above defects or improvement needs of the prior art, the present invention provides a remote digital control soft starter for AC power supply and its control method. The need for different soft-start times, the need for waiting time when restarting repeatedly, the inability to realize switching through remote input, the use of high-power devices lead to additional power consumption and heat dissipation problems, and the use of relays, transformers and other technical problems with large volume and limited life

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