Harbin Institute of Technology

Huazhong University of Science and Technology

Dianguo Xu

Ming Yang

Guihua Liu

Wei Wang

Yangyang Chen

Sibao Ding

Gaolin Wang

Wei Sun

Panbao Wang

Yijie Wang

Disclosed is a method for tuning stiffness of a servo system, including: reconstructing a characteristic signal of a servo system; calculating a vibration characteristic covariance coefficient of the servo system according to the characteristic signal; and tuning the stiffness of the servo system according to the calculated vibration characteristic covariance coefficient. By reconstructing the characteristic signal of the servo system, relationships between parameters of the system and the characteristic signal of the system are determined, and then, system stiffness tuning is carried out by calculating the vibration characteristic covariance coefficient of the system. In the process of tuning the stiffness of the servo system, a tuning judgment is made according to the system's own parameters without relying on a special locus, thus increasing the compatibility and intelligence degree of an algorithm.

Method and device for tuning stiffness of servo system and servo system

A virtual voltage injection-based speed sensor-less driving control method for an induction motor is provided. First, a virtual voltage signal is injected into a motor flux linkage and rotating speed observer so that there is a difference between an input of the motor flux linkage and rotating speed observer and a command input of the motor. Then, based on any type of the motor flux linkage and rotating speed observer, a motor flux linkage rotation angle and a motor rotor speed are estimated, and the induction motor is driven to run normally with a certain control strategy (such as vector control). Then, based on a signal designed according to this method and injected only into the motor flux linkage and rotating speed observer, the induction motor driven by a speed sensor-less control system for the induction motor may be ensured to output 150% of a rated torque when running at a motor low synchronous rotating speed and a motor zero synchronous rotating speed, and the stability thereof may be kept for a long time.

Virtual voltage injection-based speed sensor-less driving control method for induction motor

The present disclosure provides a series-connected SiC MOSFET drive circuit based on multi-winding transformer coupling. The drive circuit is mainly composed of a transformer, an energy storage capacitor and a push-pull circuit. The transformer plays a role of constraining a relationship between gate-source voltages of series-connected SiC MOSFETs to ensure that a drive voltage of each SiC MOSET in series is synchronously increased and decreased, and to prevent the problem of a dynamic voltage imbalance at moments of conduction and cutoff due to the desynchrony of the drive voltages. Both the energy storage capacitor and the push-pull structure are used to ensure that the SiC MOSFETs have sufficient drive currents at the moment of conduction to achieve fast conduction of the SiC MOSFETs. Meanwhile, a discharge loop is constructed for the gate-source voltages at the moment of cutoff to ensure that the drive voltages drop in a short period of time.

Series-connected SiC MOSFET drive circuit based on multi-winding transformer coupling

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Hubei, China

Dianguo Xu