SusTEM Special Sessions on Thermal Energy Management Technical Analysis of a Stand-Alone PVWind System with Hybrid Storage for Households Xiaonan Han, Yaodong Wang, Tony Roskilly Sir Joseph Swan Centre for Energy Research Newcastle Institute for Research on Sustainability Newcastle University, UK Contents Introduction Electricity Consumption of Household Design of a Stand-Alone Hybrid Renewable Energy System Modelling of the System Control Strategy Results and Discussion Conclusions Introduction Background Electricity Energy Storage Energy and Pollution Battery, flywheel, supercapacitor and FC • 3 major fossil fuels trend to dry up • • Renewable Energy Serious CO2 emission Global warming and Climate change Hybrid Electricity Energy Storage (HEES) consisting of battery and supercapacitor • • The stand-alone PV system • The stand-alone wind-energy system • The wind-PV hybrid renewable energy system (HRES) • Introduction (2) Background (2) (1)As much as 40% of the population in the whole world is still living in isolated households (without power supply). (2)The electricity consumption in households accounted for 29% of the total energy consumption in the UK. Introduction (2) Background (3) UK solar resource Introduction (2) Background (4) UK wind source Introduction (3) Aims and Objectives Previous 1. Electricity Energy Storage has already been considered in a PV or wind-turbine system. 2. Specific weather conditions without frequency changes are used. 3. Constant load or special load is the base of the simulation. 4. Simulation period is short. This Study 1. To propose a system which is the wind-PV HRES with the battery-supercapacitor HEES. 2. To use real weather data as input. 3. To chose a 24-hour typical load profile in a UK household for the proposed system. 4. To obtain the performance of a whole day under proposed control strategy. A Typical 24-Hour Electricity Consumption of a UK household in Winter Design of a Stand-Alone Hybrid Renewable Energy System for the Household VPV MPPT IPV VDC IAC DC/DC PV Array PWM PMSG Wind turbine VWT IWT AC/DC 240V DC Bus DC/DC DC/AC LOAD MPPT DC/DC DC/DC Battery SOC Super capacitor Energy Management System VDC PPV PWT Pload MPPT – Maximum Power Point Tracking PMSG – Permanent magnet synchronous generator PWM – pulse-width modulation Modelling of the System – Control Strategy (1) Incremental Conductance (INCond) MPPT of PV Array P V I dP dI I V 0 dV dV dI I dV V Modelling of the System – Control Strategy (2) (1) Incremental Conductance (INCond) MPPT of PV Array Start Monitor V(k)and I(k) Y V(k)-V(k-1)>0 N Y Y dI/dV=-I/V I(k)-I(k-1)=0 N N dI/dV>-I/V N Decrease Vref I(k)-I(k-1)>0 Y Increase Vref Return N Decrease Vref Y Increase Vref Modelling of the System – Control Strategy (3) (2) PSF (power signal feedback) MPPT of Wind Turbine Start Initialization L=1; M=1; D0=0.1 Monitor V(k) and I(k) Pb : Reference value of increased power L : Constant M : Step lenghth D0 : Initial duty D : Duty for the DC/DC converter P(k)=V(k)I(k) M=D0[P(k)-P(k-1)]/Pb Y P(k)-P(k-1)=0 N D(k+1)=D(k)+L*M Return Modelling of the System – Control Strategy (4) (3) Control Strategy of Hybrid Electricity Energy Storage (HEES) Pd=PPV+PWT-Pload Monitor SOC of Battery and VDC Monitor Pd and VDC N SOC>20% N Pd>0 Y Y VDC>V*DC -2%<(VDC-V*DC)/V*DC<2% N Constant-Voltage Charging -2%<(VDC-V*DC)/V*DC<2% Y Constant-Current Charging N Constant-Voltage Discharging Y Constant-Current Discharging N Constant-Current Charging Y Constant-Current Discharging Buck/Boost Bi-directional Converter Buck/Boost Bi-directional Converter Battery Supercapacitor Constant-Voltage Discharging Typical Weather Data used for simulation in a Sunny Winter Day Solar Time Irradiation (W/ m2) Ambient Temperature (℃) Wind Speed Solar Time Irradiation (W/ m2) (m/s) Ambient Temperature (℃) Wind Speed (m/s) 00:00 0 6 11 12:00 641 5 19 01:00 0 5 11 13:00 642 5 18 02:00 0 5 12 14:00 440 4 19 03:00 0 5 18 15:00 389 4 18 04:00 0 4 17 16:00 234 4 18 05:00 0 5 16 17:00 15 4 20 06:00 0 5 19 18:00 0 4 18 07:00 4 5 18 19:00 0 3 19 08:00 54 4 15 20:00 0 3 15 09:00 283 4 15 21:00 0 3 14 10:00 451 4 16 22:00 0 2 15 11:00 572 5 17 23:00 0 2 15 Sizing PV Array Determine the Capacity Wind Turbine Supercapacitor Battery Sizing Two WT6000 Wind Turbines Model Manufacturer Cut-in Wind Speed (mph) Rated Wind Speed (mph) Cut-out Wind Speed (mph) Rated Output Power (W) Battery System Available Voltage (V) WT6000 Proven Engineering 6 22 145 6000 48,120,or 240 A 3.3kW PV Roof System Power Type of Cell Number of Cells Cell Efficiency Maximum Voltage at Maximum Power Point (V) Maximum Current at Maximum Power Point (A) Dimensions (mm) Weight (kg) 190W +/-3% Monocristallin 72 17.7% 37.3 5.1 1580×808×40 14.8 Sizing (1) Battery Model Voltage (V) Capacity (Ah) Dimensions (mm) Weight (kg) NPL100-12 12 100 407×172.5×240 39 Model Rated Capacitance (F) Rated Voltage (V) Rated Current (A) Gravimetric Specific Energy (Wh/kg) Volumetric Specific Energy (Wh/l) Dimensions (mm) Weight (kg) EMHSP-0094C0-045R0 94 45 340 (2) Supercapacitor 2.8 3.7 212×193×201 11 Simulation Results and Discussion PV Power output Load Wind turbine Battery Supercapacitor Simulation Results and Discussion (2) (1) Output of the Generation Units Output of the PV System Output of the Wind-Turbine System Simulation Results and Discussion (3) (1) Output of the Generation Units Difference between Supply and Household Load (Pd=PPV+PWT - Pload) Simulation Results and Discussion (4) (2) HEES Implement The state of charge (SOC) of the Battery over the Whole Typical Day Simulation Results and Discussion (5) (3) Voltage of the Junction Point Voltage of DC Link in the Proposed System Voltage of DC Link in the System without Supercapacitor Conclusions A stand-alone wind-PV system with a HEES consisting of a battery and supercapacitor is proposed with an optimised control strategy. Real typical data is used as the base of simulation after analysis. The proposed system can supply sufficient and stable electrical energy to an isolated 00 the correspondingly bad household during weather condition for 24 hours. The output of the PV array and the wind turbine were always retained at the MPP with the fast changing weather conditions due to the use of MPPT. The DC voltage at the junction can be maintained within an acceptable fluctuation range in the whole day. Performance of the proposed system Conclusions (2) … Other Alternative Energy Converter DC/DC Optimal Sizing PV Array PMSG Wind turbine AC/DC DC/DC DC Bus DC/AC DC/DC EES Consider about CCHP Combined with Biofuel Technology Further Research LOAD