Improving the Storage Capability of a Microgrid with a Vehicle-to-Grid Interface

Transcription

1 Improving the Storage Capability of a Microgrid with a Vehicle-to-Grid Interface Vicente Leite, Ângela Ferreira and José Batista Polytechnic Institute of Bragança, Portugal

2 Outline Motivation The IPB microgrid Energy storage capability IPB Eco Buggy V2G and G2V interface Bidirectional power converter topology Control strategies Simulation results Experimental results Conclusions

3 Motivation Energy storage systems enhance the exploitation of Renewable Energy Sources (RES) Minimization of intermittency and variability effects of most RES Balance in system cost Contribution to frequency and voltage stability by providing ancillary services Backup active power, acting as a manageable load and discharging energy back to the grid when necessary Reactive power support Peak-shaving Under a microgrid concept, plug-in electric vehicles (PEV) have an important distributed energy storage capacity Deployment of battery chargers to allow a bidirectional power flow Grid-to-Vehicle (G2V) and Vehicle-to-Grid (V2G) concept

4 IPB Microgrid Infrastructures PV glass facade of the library Photovoltaic systems Wind turbine Pico hydro power plant SB 21TL SB 3 WB 17 WB 12 SB 12 Bi-directional battery inverter for off-grid systems SB 548 Microgrid 23V, 5Hz Loads DC voltage LiFePO4 Battery Biodiesel production unit ECO Buggy IPB Generator Battery bank Microgrid set up in the laboratory

5 Energy storage capability Semi-automatic production unit of biodiesel from used cooking oil and (bio)diesel GenSet (5 kw) Bank of batteries 8 6V, 2A Electric vehicle battery

6 IPB Eco Buggy Motor Axial Flux PMSM High efficiency High torque density 13 kw; 64,87 V; 149,5 A; 6 rpm; 2,7 Nm; 8 poles; 4 Hz Battery LiFePO 4 Low cost of raw materials Long life cycle Safety characteristics 96 V; 7 Ah; 9 Kg

7 V2G/ G2V interface Bidirectional power converter topology

8 V2G/ G2V interface Control strategies V2G (discharge) and G2V (charge) control P * V bat. * I b,v2g I b Current (A) * I b, G2V Voltage (V)

9 V2G/ G2V interface q i d i d vg = vgd = v Voltage Oriented Control of the VSI i q * V dc * Q * i q * i d ' v d ' v q v gd * v d * v q * * v c =v α v v gq = vg = vgd = v

10 Simulation results Vdc sim Vdc ref DC-Link Voltage (V) G2V V2G P 1 W P = 1 W P = W Q = var Q = - 4 var Q = 4 var

11 Simulation results Battery current (A) Battery voltage (V) ib sim ib ref G2V V2G P 1 W P = 1 W P = W Q = var Q = - 4 var Q = 4 var

12 Simulation results d current (A) q current (A) id ref id sim iq sim iq ref G2V V2G P 1 W P = 1 W P = W Q = var Q = - 4 var Q = 4 var

13 Simulation results Grid Voltage (V) and Current (A) Vg/3 Ig Ig amp G2V V2G

14 Simulation results Grid Voltage (V) and Current (A) Vg/3 Ig Ig amp P = 1 W P = W

15 Simulation results Grid Voltage (V) and Current (A) Vg/3 Ig Ig amp Q = var Q = - 4 var

16 Simulation results Grid Voltage (V) and Current (A) Vg/3 Ig Ig amp Q = - 4 var Q = 4 var

17 Experimental results Vg, V pll (V) Grid voltage and PLL output Vg Vpll id and iq (A) id iq Grid current dq components Vg/3 (V), ig and Ig (A) Step in the reactive power reference (-5 var) Vg/3 ig ig amp Vg/3 (V), ig and Ig (A) Vg/3 ig -15 ig amp Step in the active power reference (4 W) Vdc (V), p (W ), q (Var) Vdc p-meas q-meas Step in the active power reference (4 W) V dc (V ), p (W), q (V ar) Vdc p-meas q-meas Step in the reactive power reference (5 var)

18 Conclusions The V2G/G2V interface project will provide an additional energy storage element The vehicle s battery improves the storage capability of the microgrid It acts as a manageable load or generator, smoothing the load diagram The adopted topology and control strategies are able to manage bidirectional active and reactive power flow Allow reactive power support Improve the reliability and quality criteria of the energy supply

19 Muchas gracias Vicente Leite