A Photovoltaic System Model For Matlab /Simulink Simulations

1. A Photovoltaic System Model For Matlab/Simulink Simulations Cemal Keles, B. Baykant Alagoz, Murat Akcin, Asim Kaygusuz, Abdulkerim Karabiber Electrical Electronics Engineering Department Inonu University Malatya, Turkey

2. VL Vm, Im IL Behavioural PV Model Power-limited Electrical Driver Load PhotovoltaicSystem Model • This study aims to developed a general propose Simulink PV module • The proposed model is based on a behavioral cell model and an electrical driver interface: • A behavioral cell model is for solar radiance to electrical parameter conversion. • An electrical driver interface is for implementing electrical characteristic of power limited systems in power simulations PV Simulation Model

3. Behavioral PV Modeling • The overall current, which the PV cell can provide, was formulated by • The voltage of PV cell was formulated by • Vmis the output voltage, and Im is the output current • Nsc and Npc are expressed numbers of series and parallel connected PV cells

4. Behavioral PV Modeling • Simulink schema for behavioral PV model

5. Power-limitedElectricalDriverModeling • There is need for an electrical driver component that exhibits an I-V characteristic complying with the response of PV panels • Power-limited electrical driving of the electrical loads is implemented in the form of modified sigmoid function given by • The parameter φ is used to adjust decline of panel voltage Vg against the increase of load current IL

6. Power-limited Working Region of Electrical Driver PmVmIm MMP Power-limitedElectricalDriverModeling • This function can approximate to limited power I-V characteristic of PV panels for Im=0.5, Vm=1.5, and φ=20 as illustrated in

7. Power-limitedElectricalDriverModeling • Figure shows simulink model of the power limited electrical driver • Ri represents internal resistance between metal contacts of silicon layers and panel output ports • Cirepresents internal capacitance caused from capacitivestructures in the panel • These are used to configure transient response of PV module

8. SimulationExamples • The module parameters were mainly configured according to Solarex MSX60 specifications for solar radiation of 1000 W/m2 and cell temperature of 25oC • Parameter settings are listed in table

9. SimulationExamples • Tests for Constant Resistive Load • Figure shows a Simulink simulation of the proposed PV module connected to a DC resistive load • The load resistor RL was set to 4.5 Ohm for working nearby MPP • A reference radiation (G) of 1000 W/m2 and module temperature (Tc) of 25oC were used • The internal resistor Ri and capacitor Ci were set to 1 Ohm and 10-2 F, respectively

10. (a) (b) (c) SimulationExamples • Tests for Constant Resistive Load • Transient response of PV module, when connected to the resistive load, is illustrated in Figure

11. (b) (a) MMP MMP SimulationExamples • Tests for Constant Resistive Load • Figure demonstrates power injection of PV module for various values of load and load voltages • MMP points indicates power limits of PV modules • This is very useful for testing MPP tracking methods in Matlab/Simulink

12. Discrete , Cur Ts = 5 e - 005 s . Va + powergui V + Va - V - i + - Measurement Current Measurement 25 V + T A T DC V + Ra B Diode 1000 V - G DC V - C G DC / AC Converter PV Model Rb Rc SimulationExamples • Solar Power For Three Phase AC Power Distribution Simulation • Simulink simulation of a PV array supplying three phase AC distribution system is shown in Figure

13. SimulationExamples • Solar Power For Three Phase AC Power Distribution Simulation • The DC/AC converter with PWM three arms IGBT inverter causes DC instability due to periodical switching of PV module current • In order to reduce negative impacts of possible reverse current of DC/AC converter on PV module, a diode is used • Output of PV module is connected to DC/AC converter to supply 1000 Watt resistive loads per phase • In order to draw adequate power from PV module, Nsc=10 and Npc=5 were configured for the PV module

14. SimulationExamples • Solar Power For Three Phase AC Power Distribution Simulation • Figures show average magnitude of the power (PL) drawn from PV module, DC voltage (VP) supplied from PV module,andline to neutral AC voltages measured from resistive loads, respectively • After a transient regime continuing 0.1 second, average power drawn from PV module goes into steady regime and settles roughly at 3000 Watt (c) (a) Transient Regime Steady State Regime (b)

15. Conclusions • This study presents a general purposes PV simulation module and its application examples in Matlab/Simulink simulation environment • This PV model is easy to configure for a desired PV response characteristics • This model directly connects to SimPowerSystems electrical circuits. • The PV module has two main parts: A behavioral model of PV cells and a power–limited electrical driver for circuit connection • The behavioral model estimates voltage and current potential of PV panel for a given solar radiation (G) and module temperature (Tc) conditions • The power–limited electrical driver implements a relevant electrical response on the load

16. Conclusions • The proposed PV module can be employed in transient analysis of power system supplied with PV panels • This model is also useful for testing MPP tracking methods • Nowadays, solar energy integration in microgrids is becoming primary concern of power system industry. Modeling renewable energy sources for a large-scale power system integration simulation is more important today. Because these simulation tools will be a part of optimal design and intelligent management process

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