Modelling Photovoltaic Systems using PSpice

Transcription

1 Modelling Photovoltaic Systems using PSpice Luis Castaner and Santiago Silvestre Universidad Politecnica de Cataluna, Barcelona, Spain JOHN WILEY & SONS, LTD

2 Contents Foreword Preface Acknowledgements xiii xv xvii 1 Introduction to Photovoltaic Systems and PSpice 1 Summary The photovoltaic system Important definitions: irradiance and solar radiation Learning some of PSpice basics Using PSpice subcircuits to simplify portability PSpice piecewise linear (PWL) sources and controlled voltage sources Standard AM1.5G spectrum of the sun Standard AMO spectrum and comparison to black body radiation Energy input to the PV system: solar radiation availability Problems References 18 2 Spectral Response and Short-Circuit Current 19 Summary Introduction Absorption coefficient a(x) Reflectance R(X) Analytical solar cell model Short-circuit spectral current density Spectral photon flux Total short-circuit spectral current density and units PSpice model for the short-circuit spectral current density Absorption coefficient subcircuit Short-circuit current subcircuit model Short-circuit current 29

3 2.5 Quantum efficiency (QE) Spectral response (SR) Dark current density Effects of solar cell material Superposition DC sweep plots and I(V) solar cell characteristics Failing to fit to the ideal circuit model: series and shunt resistances and recombination terms Problems References 39 Electrical Characteristics of the Solar Cell 41 Summary Ideal equivalent circuit PSpice model of the ideal solar cell Open circuit voltage Maximum power point Fill factor (FF) and power conversion efficiency (rj) Generalized model of a solar cell Generalized PSpice model of a solar cell Effects of the series resistance on the short-circuit current and the open-circuit voltage Effect of the series resistance on the fill factor Effects of the shunt resistance Effects of the recombination diode Temperature effects Effects of space radiation Behavioural solar cell model Use of the behavioural model and PWL sources to simulate the response to a time series of irradiance and temperature Time units Variable units Problems References 75 Solar Cell Arrays, PV Modules and PV Generators 77 Summary Introduction Series connection of solar cells Association of identical solar cells Association of identical solar cells with different irradiance levels: hot spot problem Bypass diode in series strings of solar cells Shunt connection of solar cells Shadow effects The terrestrial PV module Conversion of the PV module standard characteristics to arbitrary irradiance and temperature values Transformation based in normalized variables (ISPRA method) Behavioural PSpice model for a PV module 91

4 ix 4.7 Hot spot problem in a PV module and safe operation area (SOA) Photovoltaic arrays Scaling up photovoltaic generators and PV plants Problems References 101 Interfacing PV Modules to Loads and Battery Modelling 103 Summary DC loads directly connected to PV modules Photovoltaic pump systems DC series motor PSpice circuit Centrifugal pump PSpice model Parameter extraction PSpice simulation of a PV array-series DC motor-centrifugal pump system PV modules connected to a battery and load Lead-acid battery characteristics Lead-Acid battery PSpice model Adjusting the PSpice model to commercial batteries Battery model behaviour under realistic PV system conditions Simplified PSpice battery model Problems References 132 Power Conditioning and Inverter Modelling 133 Summary Introduction Blocking diodes Charge regulation Parallel regulation Series regulation Maximum power point trackers (MPPTs) MPPT based on a DC-DC buck converter MPPT based on a DC-DC boost converter Behavioural MPPT PSpice model Inverters Inverter topological PSpice model Behavioural PSpice inverter model for direct PV generator-inverter connection Behavioural PSpice inverter model for battery-inverter connection Problems References 177 Standalone PV Systems 179 Summary Standalone photovoltaic systems The concept of the equivalent peak solar hours (PSH) Energy balance in a PV system: simplified PV array sizing procedure Daily energy balance in a PV system Instantaneous power mismatch 188

5 7.4.2 Night-time load Day-time load Seasonal energy balance in a PV system Simplified sizing procedure for the battery in a Standalone PV system Stochastic radiation time series Loss of load probability (LLP) Comparison of PSpice simulation and monitoring results Long-term PSpice simulation of standalone PV systems: a case study Long-term PSpice simulation of a water pumping PV system Problems References Grid-connected PV Systems 215 Summary Introduction General system description Technical considerations Islanding protection Voltage disturbances Frequency disturbances Disconnection Reconnection after grid failure DC injection into the grid Grounding EMI Power factor PSpice modelling of inverters for grid-connected PV systems AC modules PSpice model Sizing and energy balance of grid-connected PV systems Problems References 242 Small Photovoltaics 245 Summary Introduction Small photovoltaic system constraints Radiometric and photometric quantities Luminous flux and illuminance Distance square law Relationship between luminance flux and illuminance Solar cell short circuit current density produced by an artificial light Effect of the illuminance ' Effect of the quantum efficiency I(V) Characteristics under artificial light Illuminance equivalent of AM1.5G spectrum Random Monte Carlo analysis Case study: solar pocket calculator Lighting using LEDs 260

6 xi 9.11 Case study: Light alarm PSpice generated random time series of radiation Long-term simulation of a flash light system Case study: a street lighting system Problems References 272 Annex 1 PSpice Files Used in Chapter Annex 2 PSpice Files Used in Chapter Annex 3 PSpice Files Used in Chapter Annex 4 PSpice Files Used in Chapter Annex 5 PSpice Files Used in Chapter Annex 6 PSpice Files Used in Chapter Annex 7 PSpice Files Used in Chapter Annex 8 PSpice Files Used in Chapter Annex 9 PSpice Files Used in Chapter Annex 10 Summary of Solar Cell Basic Theory 333 Annex 11 Estimation of the Radiation in an Arbitrarily Oriented Surface 339 Index 353