Design And Realization Of A Single Phase Impedance Measuring Device Based On DSP

This thesis first introduces the state of arts of the single-phase impedance measuring technology as well as the problems in the exist apparatuses. Then, different impedance measuring principles and their realization methods are introduced. The vector voltage/current measuring method virtues and the reasons for using voltage/current method to design are also mentioned.Secondly, according to the characteristics of the vector voltage/current method and present demand of impedance measuring apparatus, the thesis put forwards the whole framework, including realized function, hardware design scheme and partial software design idea.For hardware design, the development bases on DSP system. Considering the different requirements in diversity using occasion, the design adopts the module development. The impedance is devided into two module, which are signal acquisition module and data processing module. These two module can not only use together but also use independly.The DSP TMS320F2812 is chosen as the microprocessor unit in the design and the DSP algorithm is selected to separate the noise and useful vector signal. The high speed operation ability and abundant internal and external resources of DSP provide the equipment with advantages of high measuring speed and wide measuring range. The design provides the RS232/485 and CAN bus interface circuit for the extend ability of measuring apparatus. For using the vector voltage/current method to measure impedance, we design the signal generating electro circuits and voltage/current sampling circuits. The signal generating circuit can produce sin wave signal within 0～2kHz for the impedance measuring in the different exciting signal source simulation using voltage/current method and for the frequency sweep signal mode. The voltage/current sampling module which adopting the high precise transformers can measure respond signal in the measured impedance exactly. Introduces Unitary method for designing low pass filter without using transfer function method and adopts PLL circuit and measuring frequency by hardware which reduce errors made by frequency spectrum leakage. Realizes the real time trace of the exciting signal frequency for the precise verifying the exciting signal.About software design, this thesis gives the design of the data acquisition program,...