Sensorless Vector Control Method for Low Power Permanent Magnet Synchronous Motor

Abstract

The invention relates to a low-power permanent magnet synchronous motor sensorless vector control method. The method comprises the following steps of: (1) applying a voltage vector on an initial angle, generating a magnetic field in the corresponding direction, determining the initial position of a rotor, and starting the motor; (2) estimating the position of the rotor at a low speed; (3) dividing the rotating speed into different intervals, and estimating the position of the rotor in the switching from the low speed to the high speed according to the different intervals; (4) estimating the position of the rotor at a middle and high speed through an observer and a phase-locked loop structure. By adopting method, the low-speed estimating algorithm is simplified, the chip resource is occupied less, and the starting time is shortened; the observer and the phase-locked loop structure are combined to estimated the position of the rotor at the middle and high speed, so that the deflection is eliminated; and the switching from the low-speed estimating algorithm to the middle and high speed estimating algorithm leads to oscillation and downtime of the system, a fusion algorithm is adopted to realize the smooth transition of the two kinds of algorithms, and the application range is wide.

Description

technical field [0001] The invention relates to the technical field of motor control, in particular to the technical field of low-power permanent magnet synchronous motor control, in particular to a position sensorless vector control method for low-power permanent magnet synchronous motors. Background technique [0002] In the process of controlling the operation of the permanent magnet synchronous motor, it is necessary to detect the position of the rotor through the sensor and continuously send the position information to the controller, so higher precision is required. Especially in the occasions where the operation requirements of the motor are high, the accuracy of the rotor position is required to be higher. At present, common sensors include photoelectric encoders and resolvers. Although these sensors can detect the position of the rotor more accurately, they also bring many problems: [0003] 1) The price of the sensor is expensive, which greatly increases the cost ...

AI Technical Summary

Problems solved by technology

[0003] 1) The price of the sensor is expensive, which greatly increases the cost of the entire motor control system. In mass production, the benefits brought by reducing the use of one sensor for each product are amazing;

[0004] 2) The installation of sensors will increase the difficulty of the motor manufacturing process, resulting in an increase in the cost of the motor itself and the difficulty of maintenance;

[0005] 3) The use of sensors has certain requirements on the environment, which limits the scope of use of the motor

Such as high temperature, dust, humidity and other harsh environments will cause the performance of the sensor to be unstable, which will have a great impact on the accuracy of the sensor. At the same time, the maintenance difficulty and cost of the sensor in these places will also be greatly increased;

[0006] 4) After installing the sensor, the volume of the overall equipment will increase. For some places where the space is relatively small, the difficulty of installing the sensor will increase, such as automobile water pumps, oil pumps, etc.;

[0007] 5) It has some influence on the overall stability of the motor. After adding sensors, it is necessary to add some devices on the hardware control board, and at the same time add 4 to 6 connecting wires, etc., which increases the complexity of the structure and reduces the stability.

When the arc tangent is around 90°, the calculated rotor position will have a deviation. At the same time, the arc tangent is more sensitive to noise, but in practice, noise is inevitable, so many glitches will appear in the angle result of the solution.

[0013] Finally, when the low-speed estimation algorithm is switched to the medium-high speed estimation algorithm, it is usually switched directly or when the deviation between the two is within a certain range. Motor out of step to stall

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