Research On The Motor Loss And Temperature Rise Of Switched Reluctance Motor

The working principle and operating characteristics of Switched reluctance motor(SRM) are different from traditional AC motor because of its doubly salient structure. The core magnetic field of SRM varies intricately and the flux density waveform is closely related to motor structure parameters such as speed, winding connection, control strategy and working condition and so on. Therefore, the calculation of losses for SR motor, iron loss in particular, is very difficult. Loss generated during motor operation eventually would be converted to heat, which causes temperature rise inside the motor. Ultimately, temperature rise affects the reliability and service life of the motor. Thus, analysis of loss and temperature rise for SRM is a key to improving efficiency and optimizing performance. However, research on iron loss and heat analysis for SRM is not in-depth. So this paper will launch a series of analytical studies and experimental verifications on losses and temperature rise for SRM.This paper chooses a three-phase 12/8 SRM as the research object. First of all, finite element simulation model of SRM is established in Ansoft to performe the 2D transient magnetic analysis, and then the flux density waveforms and their variations in different parts of the motor are given. Secondly, based on the the magnetic field datas, this paper combines the double-frequency method with the ellipse method to calculate iron core loss of SRM and analyzes distributions of iron core loss in the different parts of the motor. Again, the thermal analysis model of SRM, who is on the basis of the result of copper loss and iron loss, is built to conduct transient thermal analysis through ANSYS. This section concentrates on the effects of external cooling conditions on the motor temperature rise and temperature distributions of SRM and temperature curves in the different position of the motor.Finally, a Switched Reluctance Starter / Generator System platform whose control system core is TMS320F2812 DSP and CPLD is built. The design and debug of hardware and software are completed to realize the electric operation and generating operation of SRM. The calculation of iron loss is finished indirectly according to the test results of speed, voltage, current, power, torque and so on. Those results verify the feasibility of the selected iron loss calculation method. Temperature in different parts of stator are gotten by using the temperature measurement and display system which consists of T-type thermocouples, MAX31855 thermocouple-to-digital converter, DSP, RS-485, and a touch screen.