AY 2022 23 Test 4 Numerical part with solutions

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ELECTRIC CONVERSION FROM GREEN SOURCES OF ENERGY Prof. Alberto Dolara 1 ©Prof. Alberto Dolara – All rights reserverd Numerical exercise 1 < 26 January 2024 > An Electric Vehicle (EV) charging station consists of: ► 1 PhotoVoltaic (PV) generator; ► 1 Battery Energy Storage System (BESS); ► 4 fast charging points; ► connection to AC three-phase Medium Voltage (MV) grid by means of a transformer and AC/DC static converter; as sketched in the figure on the right. PV generato r and charging points are connected by means of a DC micro grid whose voltage is kept constant at the value of 750 V. Charging points have been designed only to charge EVs batteries. Ratings are reported in the follow: PV generator: ► Maximum power, P PV 500 kW ► Rated voltage, VPV 690 V PV generator converter (DC/DC A): ► Rated power, PDCDC-A 500 kW ► Maximum power point voltage range, VMPP from 280 V to 860 V Battery Energy Storage System (BESS) and DC/DC B converter: ► Rated power, PBESS 300 kW ► Power processor battery side voltage range, VBESS from 500 V to 650 V ► Rated battery voltage, VBESS 600 V ( VOC @SOC = 1) ► Rated capacity, CBESS 1200 Ah Charging points (DC/DC C, each): ► Rated power, PChargingPoint 200 kW ► Battery side voltage, VBatterySide from 300 V to 400 V Transformer nameplate: Rated frequency fn 50 Hz Vector group Dy11 Nominal apparent power SMVn 640 kVA Voltage ratings Nominal voltage MV (line-to-line) VMVn 23 kV Nominal voltage LV (line-to-line) VLVn 400 V Short circuit tests Short circuit voltage vcc 6 % Short circuit power factor cos(ϕcc ) 0.25 Open circuit test Open circuit active power P0 2200 W Open circuit current I0 0.8 % (continued on next page) PV Generator Inverter Trafo LV MV DC/DC B DC/DC A DC/DC C EV k, k=1, …, 4 4x BESS 2 ©Prof. Alberto Dolara – All rights…