Study And Development Of Iron Loss Tester Based On STM32

Electrical steel is a FeSi soft magnetic alloy of very low carbon content. It isindispensable soft magnetic materials of electricity, electronics and military industry.It is primarily used in manufacture of electric motors, generators, transformers coreand a variety of telecommunications equipment. Electrical sheet steel in the alternatingmagnetic field consumed invalid electrical energy, known as the iron loss.The iron losschanges into heat, and causes rising of the temperature of motors and transformersand other equipment, also causes a lot of power loss. Therefore, the iron loss is one ofthe most important indicators of the magnetic properties of electrical steel products.To measure the iron loss for electrical steel sheet is a primary method to judge thequality of electrical steel sheet, which brings the producers of motors and transformersmore convenience.The method of Epstein square electrical sheet steel test is widely used as an im-portant method of iron loss test and become a country's national standards. However,there are much weaknesses in this method,such as complicated sample preparationand loading, the need for stress relieving, and wasting large amounts of sample ma-terial, and so on. The requirements of electrical steel sheet iron loss on-site testingis not suitable for small and medium enterprises in Zhejiang Province. As a result,a portable application on-site inspection of the iron loss tester based on the nationalstandard GB/T 13789 is proposed. And the research project is supported by Scienceand Technology Department Fund of Zhejiang Province (2007C21088).In this paper, on the basis of the full study of traditional and widely used ironloss tester, the research and development of single sheet tester based on STM32 is pro-posed. STM32 is the latest ARM-based Cortex-M3 CPU microprocessor. Cortex-M3is the first based on ARMv7-M architecture of 32-bit standard processors with lowpower consumption, low gate count, short interrupt latency, low-cost advantages ofdebugging. The prototype of iron loss tester based on STM32F103RC microcontrolleris produced. DAC integrated in the microcontroller of the test instrument producessignal which is used as excitation power. Then, the intensity of magnetic inductionis automatically adjusted by digital feedback technology to maintain waveform and amplitude stability. This iron loss tester can accurately measure iron loss of electri-cal sheet steel in di?erent magnetic induction intensity on the di?erent thickness ofdi?erent densities. In addition, the tester also has automatic identification test probeposition function. When the test probe to leave the test sample, the system will auto-matically stop working, thus avoiding work long hours. The project's research resultshave applied for 3 national invention patents, and has received the admissible of theState Intellectual Property O?ce.The results show that, the errors of the ?ux density and waveform factor areboth e?ectively ensured within 0.1% by the single sheet tester based STM32 with dig-ital feedback waveform control technology. The waveform of ?ux density can meetthe requirement of sinusoidal. So that the testing speed is more quickly, more accu-rately(comparing with the National Institute of Metrology test results) for users ofelectrical steel sheet to meet the testing needs of iron loss.