Intelligent bypass system for high-voltage frequency converter

Abstract

The invention discloses an intelligent bypass system for a high-voltage frequency converter. The intelligent bypass system comprises a high-voltage solid soft starter, a first switch, a second switch, a first contactor, a second contactor, a third contactor and a three-phase resistor, wherein the first switch, the first contactor, the high-voltage solid soft starter and the second switch are in series connected in turn; the other end of the first switch is connected with the input end of the high-voltage frequency converter; the other end of the second switch is connected with the output end of the high-voltage frequency converter; the second contactor is in parallel connected with the two ends of the high-voltage frequency converter; the three-phase resistor is in short-circuit connection by one end; the other end of the three-phase resistor is connected with one end of the third contactor; and the other end of the third contactor is connected with one end at which the second switch is connected with the high-voltage solid soft starter, When a bypass circuit is processed, after the third contactor is closed to demagnetize a motor, the third contactor is disconnected and the first contactor is closed; and after the high-voltage solid soft starter is started and the motor is restarted, the second contactor is closed and the first contactor is disconnected. By using the intelligent bypass system for the high-voltage frequency converter, the motor can be switched to a power frequency voltage to operate stably and reliably, so that the problem that an impact current is overhigh when the bypass circuit is processed is solved.

Description

technical field [0001] The invention relates to the technical field of motor control, in particular to an intelligent bypass system of a high-voltage frequency converter. Background technique [0002] The high-voltage frequency conversion speed regulation system has been widely used in the energy-saving transformation of motors because of its superior speed regulation performance and energy-saving effect. High-voltage frequency converter usually includes two circuits of frequency conversion and power frequency. Under normal circumstances, the grid voltage is transformed through the frequency conversion circuit according to the system V / F curve and the frequency value given by the user, and then added to the motor stator side to control the speed of the motor; in the case of a fault in the frequency converter, The system adopts manual bypass or automatic bypass technology to switch to industrial frequency bypass operation. [0003] When the high-voltage inverter fails, rega...

AI Technical Summary

Problems solved by technology

[0004] Excessive inrush current will have the following negative effects: first, it will cause the stator winding of the motor to heat up, causing damage to the motor; second, it will pollute the power supply grid, causing the bus voltage to drop, affecting the normal operation of other equipment, and even the motor itself It cannot be restarted; thirdly, it may cause the system protection equipment to operate and affect the power supply reliability of the entire busbar

At present, there is no good solution to this problem

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