耐压泄漏安全测试及关键技术的研究

【作者】 董文军；

【导师】 汪仁煌；

【作者基本信息】 广东工业大学 ， 检测技术与自动化装置， 2004， 硕士

【摘要】 中国的家用电器发展迅速，需要大量相关的测试仪器，其中电器安全性测试是家用电器质量的一项重要指标，研制一台高可靠，高精度的电器安全测试仪对于安全用电和国民经济的发展具有重要的现实意义。 本文分析了目前在测试仪器开发过程中存在着效率低，重复劳动多的问题。提出了使用结构化的模块设计方法来设计仪器，将仪器中常用的功能进行电路的模块化设计，不同仪器的硬件差异都通过对电路的模块化设计进行封装，同时使用硬件的接口规范。软件开发使用结构化C语言，其可读性好，具有很好的可移植性，有利于今后的维护与升级。还具体介绍了耐压泄漏测试仪的工作原理及具体设计方案，采用了软硬件模块化的设计方法，加快了仪器的开发进度，对其中主要电路：有效值测试、AD转换和硬件保护电路进行了介绍。 本文进一步对此测试仪中的关键技术测试高压交流电源进行了研究，目前市面上同类仪器均采用笨重的自耦变压器加工频升压变压器的方法来实现，不符合当前电子产品向轻巧，小型化发展的方向。本文设计了基于SPWM调制方式的开关式高压正弦波逆变器来替代原有的高压装置。逆变器采用双CPU结构，使用SPI进行连接，主CPU完成输入、输出和SPWM波形数据的计算，从CPU接收到SPWM数据后使用查表方法输出SPWM波形，使用硬件电路生成死区时间防止桥臂直通，对输出功率模块进行了过流、短路、过压、过热保护。此设计方案具有结构简单可靠，可以根据需要随时改变SPWM的调制参数，输出的波形质量好，具有灵活和较高的性价比。为了减少开关电源的EMI，还设计了非连续导电模式的PFC功率因素校正电路，不但减少了因高频开关斩波对电网不良影响，还降低了对仪器本身的干扰。 整个设计也采用了规范的设计方法，在选定SPWM调制方案之后使用数学模型并用数学软件工具matlab对SPWM调制方案进行了数学上的验证，证明由牛顿迭代法生成的SPWM数据其谱分布与理论上的证明是一致，再使用protel99SE的物理电路模型仿真功能，对实际的电路模型进行仿真，也证明此方法可行，最后使用物理电路实现了SPWM正弦波输出。更多还原

【Abstract】 A great deal of test instruments will be demanded with home electronic appliances developing in China. The safe test is related to the quality of home electronic appliances directly. So developing a stable and high accurate safe-test instrument is important.The paper analyses the inefficiency in developing instruments and adopts the module method to develop the instrument, which can improve the efficiency. For hardware, the often used parts will be designed in the module board with the standard interface defined. For software, C that is readable and can masks the differents between the different hardware is adopted. The paper also introduces the design of the high-voltage test and leak test instruments and the key unit circuit such as RMS measure, AD conversion, Hardware protect.The paper explores the high-voltage AC power further. The high voltage part of the same kind products in market is composed of bulking transformer which isn’t according to the trend to minitype. A switch high-voltage sine out inverter based on SPWM is designed instead of the old transformer. This inverter adopts the double CPU which are communicated with SPI. Master CPU works with user interface and SPWM calculation. Slave CPU receives the SPWM data and output the SPWM wave by query the SPWM table. The dead time is generated by hardware to prevent the H bridge arm from short directly. The power out module is protected for over current, over voltage and over heat. This design is simple and flexible, the parameters of spwm are adjustable, and the sine output is quality. In order to reduce EMI, PFC is designed which eliminate the disturb to power net and itself.The design adopts the normative procedure. First, the SPWM is validated by math tool matlab, which prove the data of SPWM is consistent with the theory. Second, the SPICE circuit model is simulated by protel99SE which is also proved. Finally, the sine in SPWM is output by actual physical circuit. The math is important to the success of the design.更多还原