| With the development of technology, electric and electronic devices have been widely used in our daily production and lives. For safety and stability, these devices must have a good insulation. The insulation of a coil is a fundamental factor of the insulation of the whole device. So the insulation of the coil is a necessary test item before leaving the factory. Impulse winding test is a device which can measure the insulation. The best performance in the world can reach 200M sampling rate,5KV high voltage output,1% repetitive error, this is the design target of my thesis.This project comes from the industry-university-research cooperation. Followed is the measuring theory and method:when the coil is connected to a capacitor with initial voltage, they will oscillate if the Q value is suitable. By sampling and analyzing the oscillation wave of the standard coil and the tested coil, the device can determine the fault type of the coil, including damage of the coil surface, short circuit, open circuit, etc.This device consists of these items:high voltage unit, high-speed sampling unit, signal condition unit and software program. In the high voltage unit, inverter and voltage multiplying circuit are used to achieve the set high voltage. In the high-speed sampling unit, FPGA controls the sampling sequence of ADC08200 to sample the oscillation wave, FPGA also realizes 8k-FIFO to store the wave data. In the control unit, ARM core board and the extended base board are used to realize the signal condition and HMI function. Linux OS is used to separate the program level and simplify the software design. Qt is used as the HMI design tool, which provides a more comfort operation experience. In the end, lots of experiments are conducted, lots of statistics analyzed to assess the device performance.This paper can be divided into six chapters.The first chapter describes the application background and research status, make a comparison of the performance between existing devices and analyze the difficulty and development trend of impulse winding tester.The second chapter focuses on the measuring theory. Measuring model is given firstly to describe how this device works, then the following paragraphs introduce what difference the coil faults bring to the oscillation wave, finally some parameters of the wave difference are promoted to determine the faulty types.The third chapter introduces the architecture design of the device. In this chapter, system function and performance specification are analyzed firstly to determine which aspect to focus when designing this system, then solutions of several extremely important items are compared to choose the best one.In the fourth chapter, hardware design is specified in detail. According to the measuring theory, this chapter describes how the chips are chosen and how the circuits work.In the fifth chapter, software design is specified in detail. Software can be divided into three levels:hardware driver level, operation system level and application program level.In the sixth chapter, problems and solutions during the system debugging are given. Some statistics are also shown and analyzed to assess the device performance.The prototype of the device has been finished and are being modified and improved. All the targets of the existing prototype have achieved the requirements. |
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