Design And Research On Portable Calibrator Of Capacitance

The capacitance used for reactive power compensation equipment is an important instrument indispensably in the power grid, and it cannot be neglected in transmission-line system of electric power running. Consequently, the research of portable capacitance calibrator, which used for field calibration, is useful and even significant.This thesis mainly deals with the research of a kind of portable on-line calibrator of capacitance based on MSP430, and which is a kind of ultra low-power mixed signal micro-controller. This calibrator is characterized by high accuracy, low power consumption, and convenient for manipulate. The whole thesis expounds the design principle and implementation in detail from hardware and software portion.In the hardware portion, the thesis introduces the whole hardware system briefly at first, which includes MSP430F149 microcontroller, LCD module, power management module, infrared communication module, keystoke module and signal regulation module. Functions of the signal regulation module, function and actualization of infrared communication specifically were introduced. A new power management module of the battery was discussed at last, and charge & discharge circuit, battery gas gauge circuit, and the DC/DC transform circuit in the module was introduced, the ultra-low power consumption of the device was emphasized in this module.In the software fraction, this thesis discussed how to make use of infrared communication module and keystoke module to suits working in sereval different circumstances. And the design of multifunctional matrix keys was introduced, as the hardware resource was saved and the management efficiency rose by this design. The calculation method of the digital signal was deduced later. Then the thesis provided the technique of inspecting the capacity of battery in the power management module.At last, the thesis explains the means of LCD module's manipulation, the effect practicality was introduced simultaneity.Some experiment results were showed, and error sources were analysis based on the results ultimately. Forming the result the conclusion could be made that the measurement accuracy level of curren and voltage from spur track of capacitance reaches 0.5%, the capacitance's measurement accuracy leve reaches 1%.Finally, by experimentation validating, this device accords with technique target, achieves anticipated function. The hardware of the device can reliable and stable run lastingly; the software is high efficiency. The whole calibrator device has reached the demand of portable, ultra-low power consumption, easy handling and high accuracy.