Asynchronous motor load torque observation method for low-precision encoder occasion

Abstract

The invention provides an asynchronous motor load torque observation method for a low-precision encoder occasion. The method comprises the steps: enabling a voltage type inverter to drive an asynchronous motor to work normally, carrying out the sampling of a current sensor in a controller, obtaining the three-phase current information of a stator, and obtaining the position information of a rotor through a low-precision encoder; performing coordinate transformation on the stator three-phase current information to obtain current data under each coordinate system; establishing a model of the electromagnetic torque of the asynchronous motor under the synchronous rotating coordinate system, and calculating the electromagnetic torque by using mechanical parameters and operating parameters of the motor; establishing a rotor position interpolation model related to a control period when the rotor position is updated every time, and inputting interpolated rotor position reference information into a sliding mode observer; feeding back rotor position information output by the sliding mode observer to a flux linkage observer for flux linkage observation; and forward feeding load torque information output by the sliding mode observer to a current loop for compensating load disturbance.

Description

technical field [0001] The invention relates to the field of motor control, in particular to an asynchronous motor load torque observation method used in the case of a low-precision encoder. Background technique [0002] In the vector control system of a three-phase asynchronous motor using a low-precision encoder, since the speed information is updated at a specific rotor position, the precise speed information at the current moment cannot be accurately obtained at low speeds, which brings great challenges to motor control. difficulty. In addition, due to the influence of operating conditions, the load changes greatly. For example, when the traction motor is working, the traction rope suddenly breaks, resulting in a sudden drop in load torque. Since the frequency bandwidth of the preset speed loop is relatively small, it cannot respond to sudden load changes in time, resulting in large fluctuations in the speed and then causing the current loop to oscillate, and in severe ...

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Problems solved by technology

[0004] The invention provides a method for observing the load torque of an asynchronous motor used in the case of a low-precision encoder, and its purpose is to solve the problem of poor speed control performance caused by a sudden change in load under the condition of a low-precision encoder

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