Power supply circuit and anti-interference method of plc for internal mixer

Abstract

The invention discloses an anti-interference method of a power supply circuit of a PLC (Programmable Logic Controller) of an internal mixer. The anti-interference method comprises the steps of reducing the voltage of the 380 V AC (Alternating Current) into a 220 V AC through a circuit breaker and a transformer in an isolated manner; and rectifying the 220 V AC into a 24V DC through a switching power supply. The anti-interference method is characterized in that a double T-type LC loss-pass filtering circuit is connected between the secondary side of the transformer and the input end of the switching power supply; the double T-type LC loss-pass filtering circuit comprises a C1 connected in parallel with the secondary side of the transformer and a C2 connected in parallel with the input end of the switching power supply; one end of an L1 and an L2 after being connected in series is connected with the C1 while the other end thereof is connected with the C2; one end of an L3 and an L4 after connected in series is connected with the other end of the C1 while the other end thereof is connected with the other end of the C2; a resistor R1 is connected between the connecting end of the L1 and the L2 and the connecting end of the L3 and the L4. As a method of connecting a double T-type LC low-pass filter and a ring-type iron core transformer in series is adopted at the power input end of the PLC, interference from electromagnetic interference and spark interference which are generated by connection and disconnection of high-order harmonics, an electromagnetic valve, a motor and a contactor of a high-voltage frequency converter to the PLC is removed, and good use effect is obtained; and the anti-interference method is applied to a control system of a high-voltage main motor for driving the internal mixer and control systems of engineering and mining equipment in other industries.

Description

technical field [0001] The invention relates to a PLC power circuit, in particular to a PLC power circuit and an anti-jamming method, in particular to a PLC power circuit and an anti-jamming method for an internal mixer. Background technique [0002] As high-voltage frequency converters and other types of frequency converters are widely used in drives such as internal mixers and other industrial and mining equipment, the pollution to the power grid is becoming more and more serious. High-order harmonics of high-voltage frequency converters, solenoid valves, and motors 1. The electromagnetic interference and spark interference generated by the connection and disconnection of the contactor will seriously interfere with the work of the programmable logic controller (PLC) used in the control system, and even cause malfunction. Contents of the invention [0003] The purpose of this invention is to provide a kind of power supply circuit and anti-jamming method of PLC for interna...

AI Technical Summary

Problems solved by technology

[0002] As high-voltage frequency converters and other types of frequency converters are widely used in drives such as internal mixers and other industrial and mining equipment, the pollution to the power grid is becoming more and more serious. High-order harmonics of high-voltage frequency converters, solenoid valves, and motors , The electromagnetic interference and spark interference generated by the connection and disconnection of the contactor will seriously interfere with the work of the programmable logic controller (PLC) used in the control system, and even cause malfunction

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