Design And Implementation Of Converter-based Data Acquisition System

Data acquisition technology is an important method that computer is able to obtain external physical quantities. With the development of modern electronic technology, data acquisition technology has been more widely used. For most basic unit of electrical equipment, power electronic converters, due to its wide range of applications in areas such as industrial, medical, telemetry, it has an extremely significance to study how to improve the accuracy and instantaneity of the data acquisition unit. At the same time with the acceleration of the switching frequency of power electronic devices, converter system has been introduced amount of electromagnetic interference. EMI not only has a significant impact on the data acquisition unit, but also reduces the rectifier working efficiency. It even affects the work of other electrical equipment, so these put forward higher requirements for the electromagnetic compatibility of data acquisition unit.First, this article elaborates the research background, technology development and basic principles of data acquisition system. Then after test on conducted interference of converter, the value is far higher than the international standard of EN55015, so the converter’s conducted interference principle is described. In order to ensure the accuracy of the data, the stability of the system and the electromagnetic compatibility, a brand new method of designing an EMI filter is proposed. This method uses current noise source establish interference model. It can avoid the tedious steps of noise source estimation method which need to estimate the value of noise source and also avoid corner frequency method caused excessive high-frequency EMI. After simulation, it is verified that EMI meet the demand of electromagnetic compatibility indicators.As FPGA and DSP have their own advantages on signal processing, a combined data acquisition system can maximize their own characteristics, which could lead to flexibility and scalability for the system. Therefore, both DSP and FPGA constitute the core of data acquisition system which can realize data acquisition functions.From the point of hardware, Cyclone series chip EP1C3, from Altera Corporation, is selected for FPGA. TMS320F2812, from TI Corporation, is selected for DSP. High-speed chip AD7656designed by ADI Corporation is selected for Analog-to-digital module. From the point of function, FPGA is used for data collection, timing control, and data cache. DSP is used to achieve the latter data processing. ADC is used to complete the conversion of analog to digital. In addition, peripheral circuits are also designed.After the completion of the system design, simulation of each module is conducted. The final results show that the designed system meets the requirements and the specification.