Towards a new technological solution for community energy storage

Abstract

Energy storage in low voltage grid is receiving increased attention due to renewables integration and consumption growth, challenges faced nowadays by grid operators. In this work, a study of main implementation issues for community energy storage (CES) is presented along with a comparison between possible solutions for the bidirectional isolated power conversion system (PCS) to interface a battery pack with the electric power grid. The aim of this research is to increase the power density of the power converter and keeping simultaneously the same reliability of traditional solutions. These goals are pursued to be achieved through the reduction of the conversion stages and utilization of new optimization methodologies to reduce the volume of the passive components. The proposed topology for the PCS is based on a matrix converter (MC) that performs a direct AC to AC conversion between the grid and a high-frequency transformer (HFT). With this solution it is possible to eliminate the traditional DC-link capacitor and obtain a single-stage power conversion with bidirectional power flow capability. This proposed solution is evaluated and compared with a conventional two-stage topology through extensive simulation. Two prototypes systems were designed for a 10kW PCS to connect the three-phase 230/400Vrms, 50Hz mains to a battery pack with voltage range of 320V to 490V. Simulation results are presented to assess the power quality provided by the front-end and the battery side converters, as well as performance evaluation and efficiency analysis.

A Critical Review on Charging Technologies of Electric Vehicles

“…This topology ensures single-stage power conversion and removes the DC link capacitor at the output of the conventional AC-DC stage. Therefore, matrix converters usually achieve higher power density when compared to traditional two-stage solutions [66,67]. The authors in [68] proposed an advanced modulation strategy to compensate for the reactive power drawn by the input filter, which reduces the input current distortion and ensures very low total harmonic distortion (THD) for the input current.…”

Modulation Methods for Direct and Indirect Matrix Converters: A Review

“…These characteristics are the reason for the present tremendous interest in matrix converters, as they allow obtaining a compact solution for a four-quadrant frequency converter [8][9][10]. As concluded in [11][12][13], the MC can achieve higher power densities when compared with equivalent two-stage power conversion solutions. Thus, it is expected that the application areas of the matrix converter are to be expanded, given its advantages of energy saving and size reduction [14].…”

EMI Filter Design for a Single-stage Bidirectional and Isolated AC–DC Matrix Converter

“…By employing an array of controlled four-quadrant power switches, the MC enables AC-AC conversion without any intermediate energy storage element [15]. The high-frequency link matrix converter (HFLMC) is a single-stage bidirectional and isolated AC-DC energy conversion system [16]. The new modulation proposed in [17] and patented in [18] allows independent control of active and reactive power (PQ control) as well as the DC current in the battery pack.…”

“…The new modulation proposed in [17] and patented in [18] allows independent control of active and reactive power (PQ control) as well as the DC current in the battery pack. By exploring the MC attributes, circuit volume and weight can be reduced, and a longer service life is expected when compared with equivalent DC-link based solutions [16,19,20]. However, due to its complex power structure, it presents EMC challenges that have to be studied in order to ensure compliance with the international standards by designing the necessary EMI filter.…”