| There are a large number of magnetic,temperature,and structural stress field problems in the design,manufacture,and operation of electrical equipment,and multiple physical factors are often coupled together.The fine analysis of large multi-physics coupling problems is very difficult.The reason,It is core problem to obtain the physical parameters of materials and design a measuring device that can obtain the coupling parameters.Electrical steel sheets are widely used in the cores of modern motors and transformers.Their magnetic properties are characterized by hysteresis,eddy current,nonlinearity and anisotropy,and depend on external factors such as temperature and stress.Therefore,It is necessary to consider the influence of these factors on the magnetic properties in solving the multi-physics coupling problem involving electrical steel sheet.This paper mainly solves some key technical problems in the measurement of vector magnetic properties of electrical steel sheets under the coupling of temperature and stress.Firstly,based on the aims of how to improve the magnetic flux density in the measurement specimen and ensure the high magnetic field uniformity of the measurement area,a vertically orthogonal double yoke structure is designed based on the SST.Due to the stress loading,the specimen is cut into a cross shape along the rolling and vertical rolling directions.The temperature is loaded by setting the target temperature through the temperature control table,issuing a PWM control signal,driving the relay,supplying power to the ceramic heater chip,then heating the specimen,and detecting the upper surface of the measurement area of the specimen by using the chip type thermal resistance.The signal is fed back to the temperature controller for real-time feedback.The loading of the stress is first determine the target tension(pressure)force value,and then the linear motor is controlled by the controller.The force sensor is used to detect the horizontal tension(pressure)force value of the specimen to be measured,and the real-time adjustment is made by comparing with the target result.The vector magnetic characteristics of electrical steel sheets are measured by combined vector B-H sensor.The detection of the vector magnetic flux density B adopts the "probe method" to avoid the specimen damage by punch winding of the B-coil method,And simplify the difficulty of specimen preparation.The detection of vector magnetic field strength H adopts "double composite H coil method".H coil coefficient is obtained by specially designed long straight solenoid with measurement software.The effectiveness of the combined vector B-H sensor measurement was verified by comparison with the measurement data of SST that is developed by BROCKHAUS,Germany.The whole measurement system consists of PXIE embedded controller,data acquisition card,low-pass filter,power amplifier,isolation amplifier,and overall measuring device.The Vector magnetic properties measurement software of electrical steel sheets is also written.Finally,In the paper,the magnetic properties of non-oriented electrical steel sheet B50A600 is measured at different magnetization angles,magnetic flux densities and axial ratios under alternating magnetization and rotational magnetization,The temperature range is from room temperature to 200°C.The direction of the tension(pressure)force vector is set to the RD or TD direction,and the range of variation is-20 MPa to +20MPa.According to the measurement results,the evolution law of vector magnetic properties of electrical steel sheets is summarized under temperature and stress coupling dependence... |
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