A full-order sliding mode observation device and method for permanent magnet synchronous motor rotor position

Abstract

The invention provides a full-order sliding mode observation device and method for the rotor position of a permanent magnet synchronous motor. The device of the invention includes a full-order sliding mode observer, a saturation function processing module and a phase-locked loop module. The permanent magnet synchronous motor in the method of the invention The stator voltage u s After passing through the full-order sliding mode observer, the observed value of the stator current and the value of the stator current i can be output s After the difference processing, the current observation error is obtained and the sliding mode function control vector F(S) is output after the saturation function processing module. The sliding mode function control vector F(S) in the saturation function processing module adopts the hyperbolic tangent function with adjustable boundary layer thickness , the boundary layer thickness is adjusted according to the switching gain g r The speed adaptive law is carried out, and F(S) is passed through the sliding mode gain matrix G 1 After the back EMF observation error is passed through the full-order sliding mode observer, the back EMF observation value is output as a state variable and fed back to the full-order sliding mode observer to participate in the update calculation. After being processed by the phase-locked loop module, the permanent magnet synchronous motor rotor position observation value and Speed ​​observation

Description

technical field [0001] The invention belongs to the field of motor control, and in particular relates to a full-order sliding mode observation device and method for the rotor position of a permanent magnet synchronous motor. Background technique [0002] In high-performance applications, mechanical sensors such as incremental photoelectric encoders, magnetic encoders, resolvers, and Hall position sensors are widely used to detect rotor information. These mechanical sensors can detect the rotor position and rotational speed of the rotor's rotating state, but it is difficult to detect the initial position of the rotor or need to be replaced with a more complete and more expensive detection device. In addition, the mechanical sensor requires a large number of leads, which reduces the reliability of the system, thereby limiting the application of permanent magnet synchronous motors in some special occasions. Especially in some harsh environments, such as mechanical sensors unde...

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Problems solved by technology

[0004] The traditional sliding mode observer has the following problems: using the sign function as the switching function causes the system to have high-frequency chattering problems, and the back EMF signal also contains high-frequency harmonic components; the introduction of the low-pass filter will cause phase delay and thus A phase compensation module has to be added; when extracting the rotor position information, the arctangent function is used to calculate, and the look-up table method will occupy a large amount of DSP memory, and it is often difficult to achieve the expected accuracy

In view of the above problems, one of the existing chattering suppression methods is to directly replace the switching function with a conventional saturation function, so that the control between the boundary layers becomes continuous, but the sliding mode gain of this method is a fixed value , which makes the sliding mode gain applicable in the low-speed section unable to meet the gain requirements in the middle and high-speed stages, which greatly reduces the chattering suppression effect of the control system

Introducing the terminal sliding mode surface into the sliding mode observer is another commonly used chattering suppression method. This method can speed up the convergence of the error variable to the required value by introducing the terminal function. However, this method has a large workload for parameter setting. Complicated operations, etc.

In addition, methods such as adding a Kalman filter and a neural network controller to the output of the sliding mode observer are also used to weaken the system chattering and increase the observation accuracy of the rotor position, but these algorithms are relatively complicated compared with the present invention. To a certain extent, it affects its application and promotion in the practice of motor position sensorless control.

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