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For the three-phase squirrel cage asynchronous motor sensorless fast Fourier transformation (FFT) speed measurement method, the number of rotor slots needs to be known in advance, and the test accuracy is easily affected by factors such as noise and acquisition time. Therefore, a sensorless high-precision speed detection method based on singular value decomposition ( SVD ) and the Prony algorithm is proposed. Based on the study of the mechanism of rotor slot harmonic speed measurement, the calculation method of integer multiple rotor slot number is given. The SVD method based on the singular value growth rate curve is used to filter the stator current and the Prony algorithm is used to identify the rotor slot harmonics to calculate the motor speed. By using finite element and numerical simulation methods, the adaptability of the proposed algorithm and analog-to-digital ( A/D ) acquisition is analyzed and studied under different operating conditions of the motor. The physical test platform is constructed and the YE90S-2 motor is measured. Simulation and experiment results show that under the same acquisition condition, the absolute error of the proposed method is only a fraction or even one tenth of the FFT speed measurement, and the test accuracy is greatly improved, which proves the correctness and accuracy of the proposed method. [ABSTRACT FROM AUTHOR]

A method of opening T-slots at the q-axis of the rotor was proposed aiming at the eddy current loss in permanent magnet AC servo motor and the difficulty in fixing surface-mounted permanent magnet. Taking 10 poles 12 slots surface-mounted permanent magnet servo motor as the research object, a prototype motor (200W,3 000r/min) with constant thickness tiled magnets was designed. By analyzing the relationship between motor rated torque, permanent magnet eddy current loss and polar arc coefficient of permanent magnet, it is pointed out that the closer the magnet is to the q-axis, the smaller the torque contribution and the greater the eddy current loss, which provides an evidence for reducing the thickness of magnets near the q-axis and slotting in the q-axis of the rotor. On this basis, the finite element simulation of the rotor slotted motor is carried out. The results show that opening the T-shaped slot on the q-axis of the rotor can weaken the harmonic magnetic field of the motor, thereby reducing the eddy current loss of the magnet, and can expand the slotting space compared with the straight slot. The T-slot structure is used to solve the fixation problem of the surface-mounted permanent magnet while reducing the eddy current loss of the magnet through the optimized design of the motor structure. [ABSTRACT FROM AUTHOR]

This document is a correction notice for an article titled "The Stressing State Features of a Bottom Frame Structure Revealed from the Shaking Table Strain Data" by Zhang et al. The correction addresses mistakes in Figures 1 and 2, as well as Table 3, which were published incorrectly due to the authors' negligence. The corrected figures and table are provided in the document. The authors state that these mistakes do not affect the scientific conclusions of the article. The original publication has been updated accordingly. [Extracted from the article]