Photovoltaic Power System

Modeling, Design, and Control

Weidong Xiao

• Publisher: Wiley
• Year: 2017
• Print ISBN: 9781119280347
• eBook ISBN: 9781119280323
• Edition: 1
• Topic: Physical Sciences
• Subtopic: Energy

Photovoltaic Power System: Modelling, Design and Control is an essential reference with a practical approach to photovoltaic (PV) power system analysis and control. It systematically guides readers through PV system design, modelling, simulation, maximum power point tracking and control techniques making this invaluable resource to students and professionals progressing from different levels in PV power engineering.

The development of this book follows the author's 15-year experience as an electrical engineer in the PV engineering sector and as an educator in academia. It provides the background knowledge of PV power system but will also inform research direction.

Key features:

• Details modern converter topologies and a step-by-step modelling approach to simulate and control a complete PV power system.
• Introduces industrial standards, regulations, and electric codes for safety practice and research direction.
• Covers new classification of PV power systems in terms of the level of maximum power point tracking.
• Contains practical examples in designing grid-tied and standalone PV power systems.
• Matlab codes and Simulink models featured on a Wiley hosted book companion website.

Chapter 1
Introduction

The photovoltaic (PV) effect is the generation of DC electricity from light. Alexandre Edmond Becquerel, a French experimental physicist, discovered the effect in 1839. More recently, scientists have discovered that certain materials, such as silicon, can produce a strong PV effect. In the 1950s, Bell Labs of the USA produced PV cells for space activities. This can be considered as the beginning of the PV power industry. The high cost of PV materials mostly prevented applications elsewhere.

Over the past 20 years, the PV power industry has experienced significant growth. PV power generation has become more and more common. The capacity of PV systems ranges from milliwatts for portable devices such as calculators, to gigawatts for power plants connected to the electricity grid. A grid-connected PV power system can be economically installed, and can be rated as low as just a few hundred watts. The advantages of PV power systems that have led to their rapid growth are:

• green, renewable
• reliability and long lifetime
• advanced manufacturing process
• static, so noise-free operations
• improving efficiency
• decreasing prices
• flexibility of construction
• highly modular nature
• availability of government support and incentives.

Using the latest technologies, the manufacturing of crystalline-based PV cells consumes significant amounts of energy, which prevents further cost reductions. The levelized cost of electricity generated using solar PVs is still high in comparison with conventional generation resources, such as coal, natural gas, and wind, according to a technical report published by the US Department of Energy's National Renewable Energy Laboratory (Stark et al. 2015). The report was based on a study of the USA, Germany, and China. Several large-scale PV power systems were announced in 2016 and projected significantly lower costs, but these must be treated as special cases. The project feasibility and system reliability need to be carefully evaluated until the projects are successfully delivered. It is clear that the price of PV products mostly reflects their quality and reliability. High-quality, certified PV products are usually more expensive than non-certified ones. It is unrealistic to judge a PV power system only on the installation cost since reliable and long-lifetime operations are always expected.

The feed-in tariff (FIT) is the major driver of the boom in PV power all over the world. The regulatory incentives are different from country to country, but all are designed to accelerate investment in PV-related technologies. One FIT example can be found on the website of the Ontario Power Authority, Canada. Parts of the FIT price schedule are shown in Table 1.1, which covers projects under 500 kW in capacity. It shows that the government contributes significant funds for PV system installations since the listed price is higher than the charge for residential consumption. It should be noted that the listed price is based on the 2016 schedule. Like FITs in most other countries, it is always subject to change. Another disadvantage of PV power systems lies in their low power density, which limits their use mainly to static applications rather than vehicles. Motor vehicles are usually considered as one of the major contributors to air pollution.

Table 1.1 Price schedule of feed-in tariffs in Ontario, Canada

Type	System capacity (kW)	Price ($/kWh)^*
Rooftop	10	0.294
	10–100	0.242
	100–500	0.225
Non-rooftop	10	0.214
	10–500	0.209

^* Canadian dollars.

1.1 Cell, Module, Panel, String, Subarray, and Array

A PV cell, also commonly called a solar cell, is the fundamental component of a PV power system. A crystalline-based solar cell features a p-n junction, as shown in Figure 1.1. The manufacturing process includes melting, doping, metallization and texturing. The positive and negative sides of the junction form the DC voltage and supply electricity when a load is connected. However, the voltage of a single p-n junction cell is less than 1 V, which is low for most practical applications. Moreover, it is mechanically fragile, and must be laminated and protected for practical use.

Figure 1.1 Typical crystalline PV cell construction.

To end users, the basic unit is the PV module or solar panel, which can produce higher voltages and more power than a single cell. A PV module consists of cells that are interconnected and laminated together. The old PV panel was usually designed to...

Table of contents

• Cover
• Title Page
• Copyright
• Dedication
• Table of Contents
• Preface
• Acknowledgments
• About the companion website
• Chapter 1: Introduction
• Chapter 2: Classification of Photovoltaic Power Systems
• Chapter 3: Safety Standards, Guidance and Regulation
• Chapter 4: PV Output Characteristics and Mathematical Models
• Chapter 5: Power Conditioning
• Chapter 6: Dynamic Modeling
• Chapter 7: Voltage Regulation
• Chapter 8: Maximum Power Point Tracking
• Chapter 9: Battery Storage and Standalone System Design
• Chapter 10: System Design and Integration of Grid-connected Systems
• Index
• End User License Agreement