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This paper demonstrates the functionality of a power electronics based energy management system (EMS). The EMS includes batteries and a digitally controlled single phase voltage source inverter (VSI) which can be controlled as a current source or a voltage source depending on the status of the AC grid and the user's preference. The EMS guarantees that the critical loads are powered when the AC grid fails; in which case the VSI is controlled as a voltage source. It also accomplishes peak power control by supplying battery power to the local loads while they are powered by the AC grid if the loads get large. The electricity cost savings accomplished by peak shaving are estimated. The EMS functionality is demonstrated by experimental measurements on a laboratory prototype. The control architecture and logic embedded in the EMS are discussed in detail.

The present paper deals with the development of a detailed model of a three-phase induction motor useful to evaluate separately common mode and differential mode currents. The proposed approach simplifies the decoupling of the common mode and differential mode current spectra, using the dqO stationary reference frame transformation, and allowing a separate analysis of the phenomena, which is useful for EM1 filter design. The proposed model can also be used to evaluate new inverter modulation techniques in terms of current harmonic generation.impedance stabilization, network (LISN), and this results in frequency spectra containing both common and differential mode components. While in a two wire system these components can be decoupled with additional equipment [l], in a three phase system this is usually not possible. The present paper will show that a qd0 stationary referenceframe transformation, allows common mode and differential mode currents components to be separately identified. A sinall signal circuit is all that is needed to achieve the transformation niaking the measurements simple and inexpensive.