Satellite Ni-mh Battery Charge Control System

Nowadays, the space technology is stepping into an era of large scale development of terrestrial space, the design of satellites which are applied in both commercial and defense applications trends toward high performance, multiple purposes and long service life. Among the sub-systems of a satellite, the performance of power source defines the performance and service life of the whole satellite. In this thesis, the theory, methods and techniques of pressure controlled charging for Ni-H₂ batteries are discussed in terms of in-orbit charging management. Currently electronic coulometer, V-T chart, digital T-V, pressure control and temperature control is adopted in foreign applications but in China's applications the electronic coulometer and V-T chart are normally used, the methods of digital T-V control, pressure control and temperature control are not yet adopted as a master controlling method.In this thesis, the control system of Ni-H2 battery is studied. First of all, the current status and the trend of the development of satellite power sources is analyzed and introduced emphasizing on the structure and working principle of the Ni-H2 which we are focused on. Secondly, the key issues in the charging control system of Ni-H2 batteries are discussed by the analysis in theory and the tests by experiments concerning the relations between the charging control method, the pressure of a Ni-H2 battery and the capacity and temperature of the battery, and a pressure controlled charging criterion is designed based on the relations discussed. Thirdly, a charging control system is designed based on the pressure controlled charging criterion and the modules of the system are tested.In this thesis, we performed the following original works on the basis of recent international research results in this field:a. We performed the first application of a constant current power source to power the pressure sensor in the Ni-H2 battery in China, and the nonlinear error of the system is removed.b. We implemented that the charge current is regulated by the pressure of the Ni-H2 battery with the introduction of temperature signals as a compensation of pressure control.c. We adopted the intermittent charging at a relatively small current instead of the long-term charging at a small constant current that was widely used before.This thesis studies the relative technologies from the angles of the implementation of pressure control charging technologies. The hardware circuit design, adjustment and software design and development are also accomplished. The result of this study may be referred by the future engineering of charging control for Ni-H2 battery and the potential economical and social benefit will also achieve progressively.