A control system for an AC motor

Abstract

The invention discloses a control system of an AC motor, comprising: a power conversion module, an overheating and overcurrent protection switch, a zero-crossing signal detection module, a relay control module, a thyristor control module and a main control module, and the main control module supplies power Turn on the relay control module first at the zero point. Since there is no high voltage at both ends of the relay in the relay control module at this time, there is no ignition phenomenon in the relay, and when the power supply zero point is detected, delay processing is performed, and the thyristor control module is turned on to start the motor. ; If the motor needs to stop working, the main control module first stops the work of the thyristor control module, thus cutting off the live wire circuit of the motor, and then stops the work of the relay control module. There is no ignition phenomenon at the moment, and the motor is controlled to start working through the relay control module and the thyristor control module at the same time, and no false trigger will occur.

Description

technical field [0001] The invention relates to motor control technology, in particular to a control system of an AC motor. Background technique [0002] AC motor is a machine used to convert mechanical energy and AC electrical energy. Currently, AC motors are widely used in the market, and are used in some stirring appliances (such as food processors) and some electric tools. [0003] The control methods of the AC motor include: 1. The power supply circuit of the motor is controlled by a single thyristor, and the voltage supplied to the motor is adjusted and controlled; 2. The power supply circuit of the motor is controlled by a single relay, and the motor current is cut off and supplied. [0004] However, there are some shortcomings in the above-mentioned motor control technology: the first one is single-circuit thyristor control, which is easily affected by the interference of the power grid and causes false triggering, so that the motor malfunctions in an abnormal state ...

AI Technical Summary

Problems solved by technology

[0004] However, there are some shortcomings in the above-mentioned motor control technology: the first one is single-circuit thyristor control, which is easily affected by the interference of the power grid and causes false triggering, so that the motor malfunctions in an abnormal state and causes harm to people; the second one is Single-way relay control, in the process of controlling high-power motors, it is easy to cause "ignition" phenomenon at the moment of starting and closing of electrical appliances, which may cause fire in serious cases, cause economic losses to consumers, and even threaten human safety

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