Method of restarting high-voltage inverter after instantaneous power failure

Abstract

The invention discloses a restarting method for a high-voltage frequency converter in momentary interruption, and relates to the field of control of the high-voltage frequency converter. The restarting method comprises the following steps of maintaining continuous normal operation of a controller of the high-voltage frequency converter after the high-voltage frequency converter is halted when a high-voltage power grid is in momentary interruption; after the power supply of the high-voltage power grid is recovered, judging whether a high-voltage motor is in a static state or not, if so, switching the controller from a restarting state to a normal starting state and starting the high-voltage motor, and if not, enabling the controller to adopt a V / F (voltage / frequency) control way to scan an operating frequency of the high-voltage motor by taking a frequency of the high-voltage frequency converter in a machine halt state as an initial searching frequency; and determining a real-time frequency of the high-voltage motor, after the real-time frequency is determined, switching the controller from the restarting state into the normal starting state, and starting the high-voltage motor by taking the real-time frequency as a restarting initial output frequency of the high-voltage frequency converter. By adoption of the restarting method, non-impact starting in high-voltage power supply recovery can be realized, and the starting is safe and steady.

Description

technical field [0001] The invention relates to the control field of high-voltage frequency converters, in particular to a method for restarting high-voltage frequency converters after momentary power failure. Background technique [0002] With the rapid development of modern industrial technology, high-power high-voltage motors are more and more used in various power transmission systems, especially large loads such as fans and pumps in metallurgy, chemical, petroleum and other industries. There are higher requirements for the starting and speed regulation of the motor. [0003] At present, the high-voltage frequency converter has been able to meet the start-up and speed regulation requirements of high-power high-voltage motors. But for loads with a large moment of inertia like a large fan, the stop time in the free stop mode is quite long. When the power grid fails for a short time during operation, and then the power supply is restored, the rotor of the motor is still i...

AI Technical Summary

Problems solved by technology

But for loads with a large moment of inertia like a large fan, the shutdown time in the free stop mode is quite long

When the power grid fails for a short time during operation, and then the power supply is restored, the rotor of the motor is still in the rotating state. At this time, if the inverter is directly put into operation, a large inrush current will be generated, which will cause certain damage to the inverter and the motor. damage, so it is necessary to wait for the motor to come to a complete standstill before starting it again

[0004] However, the long restart waiting time not only affects the production efficiency, but also cannot meet some production processes that have high requirements on the production process, which requires the high-voltage inverter to have the function of restarting after the instantaneous power failure of the power grid

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