In this paper, a new online capacitance estimation method for dc-link capacitors in a three-phase ac/dc/ac pulsewidth-modulation converter is proposed. A controlled ac voltage with a lower frequency than the line frequency is injected into the dc-link voltage, which then causes ac power ripples at the dc output side. By extracting the ac power component on the dc output side using digital filters, the capacitance can then be calculated using a support vector regression method. A function that defines the relation between a given capacitor power and its corresponding capacitance is determined using a set of training data. This function is then used to predict the output for the given input which is not included in the training set. The proposed method can be simply implemented with only software and no additional hardware. Experimental results confirm that the estimation error is less than 0.15%.

Intelligent Building technologies have a potential significant impact on sustainability issues (energy efficiency, due diligence, health and safety and indoor environment).It is widely recognized that intelligent building can improve the environmental and economic performance of buildings. Consequently, the promotion of intelligent buildings is regarded as means of fostering sustainability. Intelligent building technology encompasses sophisticated systems targeting various facets of building automation. Developing such an integration system of intelligent buildings technologies can significantly increase the energy efficiency of the building while also providing enhanced occupant comfort and cost effectiveness. Given the developments in information and communication technology and the increasing level of complexity of intelligent building systems, this paper introduces an integration system that facilitates improving the utilization of intelligent building technologies. The proposed system in this paper provides three indispensable sets of criteria by which successful integration of intelligent building technologies can be achieved. These measures are integration criteria for sub-system operation, best practices of sub-system business considerations,and interoperability criteria. Detailed and articulated measures for each set of these criteria are introduced. The paper explores the potential benefits of integrating intelligent building technologies as a useful means for fostering sustainability in buildings.