Current-voltage and power-voltage characteristics of large photovoltaic (PV) arrays under partially shaded conditions are characterized by multiple steps and peaks. This makes the tracking of the actual maximum power point (MPP) [global peak (GP)] a difficult task. In addition, most of the existing schemes are unable to extract maximum power from the PV array under these conditions. This paper proposes a novel algorithm to track the global power peak under partially shaded conditions. The formulation of the algorithm is based on several critical observations made out of an extensive study of the PV characteristics and the behavior of the global and local peaks under partially shaded conditions. The proposed algorithm works in conjunction with a DC-DC converter to track the GP. In order to accelerate the tracking speed, a feedforward control scheme for operating the DC-DC converter is also proposed, which uses the reference voltage information from the tracking algorithm to shift the operation toward the MPP. The tracking time with this controller is about one-tenth as compared to a conventional controller. All the observations and conclusions, including simulation and experimental results, are presented.

Maximum Power Point Tracking Scheme for PV Systems Operating Under Partially Shaded Conditions

This paper proposes an improved maximum power point tracking (MPPT) method for the photovoltaic (PV) system using a modified particle swarm optimization (PSO) algorithm. The main advantage of the method is the reduction of the steady- state oscillation (to practically zero) once the maximum power point (MPP) is located. Furthermore, the proposed method has the ability to track the MPP for the extreme environmental condition, e.g., large fluctuations of insolation and partial shading condition. The algorithm is simple and can be computed very rapidly; thus, its implementation using a low-cost microcontroller is possible. To evaluate the effectiveness of the proposed method, MATLAB simulations are carried out under very challenging conditions, namely step changes in irradiance, step changes in load, and partial shading of the PV array. Its performance is compared with the conventional Hill Climbing (HC) method. Finally, an experimental rig that comprises of a buck-boost converter fed by a custom-designed solar array simulator is set up to emulate the simulation. The soft- ware development is carried out in the Dspace 1104 environment using a TMS320F240 digital signal processor. The superiority of the proposed method over the HC in terms of tracking speed and steady-state oscillations is highlighted by simulation and experimental results.

An Improved Particle Swarm Optimization (PSO)–Based MPPT for PV With Reduced Steady-State Oscillation

Solar power generation by PV (photovoltaic) technology: A review

Public awareness of the need to reduce global warming and the significant increase in the prices of conventional energy sources have encouraged many countries to provide new energy policies that promote the renewable energy applications. Such renewable energy sources like wind, solar, hydro based energies, etc. are environment friendly and have potential to be more widely used. Combining these renewable energy sources with back-up units to form a hybrid system can provide a more economic, environment friendly and reliable supply of electricity in all load demand conditions compared to single-use of such systems. One of the most important issues in this type of hybrid system is to optimally size the hybrid system components as sufficient enough to meet all load requirements with possible minimum investment and operating costs. There are many studies about the optimization and sizing of hybrid renewable energy systems since the recent popular utilization of renewable energy sources. In this concept, this paper provides a detailed analysis of such optimum sizing approaches in the literature that can make significant contributions to wider renewable energy penetration by enhancing the system applicability in terms of economy.

Optimum design of hybrid renewable energy systems: Overview of different approaches

It has become imperative for the power and energy engineers to look out for the renewable energy sources such as sun, wind, geothermal, ocean and biomass as sustainable, cost-effective and environment friendly alternatives for conventional energy sources. However, the non-availability of these renewable energy resources all the time throughout the year has led to research in the area of hybrid renewable energy systems. In the past few years, a lot of research has taken place in the design, optimization, operation and control of the renewable hybrid energy systems. It is indeed evident that this area is still emerging and vast in scope. The main aim of this paper is to review the research on the unit sizing, optimization, energy management and modeling of the hybrid renewable energy system components. Developments in research on modeling of hybrid energy resources (PV systems), backup energy systems (Fuel Cell, Battery, Ultra-capacitor, Diesel Generator), power conditioning units (MPPT converters, Buck/Boost converters, Battery chargers) and techniques for energy flow management have been discussed in detail. In this paper, an attempt has been made to present a comprehensive review of the research in this area in the past one decade.

Hybrid renewable energy systems for power generation in stand-alone applications: A review

Permanent magnet synchronous motor (PMSM) as a railway traction system has begun to be introduced in some commuter lines. In comparison with the common induction motor (IM), PMSM has different loss characteristics. Namely, during coasting, the production of iron loss still exists due to the rotating permanent magnet which increases energy consumption. Conventionally, no traction energy is consumed during coasting and thus, coasting is often exploited to configure optimal train speed profile. However, this feature might not be applied in PMSM. In this paper, the optimal train speed profile for PMSM is configured with dynamic programming (DP). To include the effect of coasting, the train energy consumption is modeled using the Maximum Torque Per Ampere (MTPA) control method. The result shows that the energy is consumed during coasting due to d-axis current flowing to the motor to suppress the back-emf. Moreover, the regenerative braking can achieve an efficiency of more than 88%. In addition, the optimal train speed profile for PMSM utilizes less coasting, and during braking, maximum deceleration is utilized more compared to the conventional model.

Design of Optimal Train Speed Profile for PMSM Railway Traction System Using Dynamic Programming with MTPA Control Method

1A11 METHODS OF MODELING AND CALCULATION OF A FEEDING CIRCUIT FOR EVALUATING ENERGY EFFICIENCY AND OPERATIONAL ROBUSTNESS BY TRAIN TRAFFIC SIMULATION Masafumi Miyatake (Sophia University, Japan) 1A12 RADIO COMMUNICATION NETWORK SIMULATOR TO EVALUATE STABILITY OF RADIO COMMUNICATION BASED TRAIN CONTROL SYSTEMS Kunihiro Kawasaki (Railway Technical Research Institute, Japan) 1A13 DEVELOPMENT OF SECURE RADIO SYSTEM Hisashi Kimura (East Japan Railway Company, Japan) 1A14 DEVELOPMENT OF A SYSTEM TO UTILIZE TABLETS FOR IMPROVED RESPONSE TO ABNORMAL SITUATIONS Hideto Murakami (East Japan Railway Company, Japan) 1A15 EFFECT OF PROTOTYPING OF ONLINE LOADING SYSTEM AT THE STAGE OF EXAMINING SPECIFICATIONS Sei Takahashi (Nihon University, Japan)

1A11 Methods of modeling and calculation of a feeding circuit for evaluating energy efficiency and operational robustness by train traffic simulation(Electrical-Power)

3E24 Rational placement of charging-station for Lithium-ion battery onboard of rail vehicles(Electrical-Vehicle)

This paper presents a novel system topology and control scheme of a selective dual mode pulse modulated high efficiency single-phase sinewave power conditioner for new energy generation and storage applications. This power conversion system is composed of a time-sharing sinewave absolute value tracking soft switching boost chopper with a bypass diode and sinewave PWM full-bridge (FB) inverter in the second power stage without electrolytic capacitor DC link operated by a dual mode selective time-sharing pulse pattern signal processing control approach. The circuit configuration and the unique operating principle of the proposed power conditioner are described and discussed with a design example and the power conditioner is evaluated through experimental and simulation results.

http://ieeexplore.ieee.org/iel5/4123465/4123466/04123596.pdf

A Stand-Alone One-Stage Power Conditioner Using Time-Sharing Sinewave Tracking Bypass Diode Assisted- Boost Soft Switching Chopper and PWM Inverter

This paper examines the implications of changing of operating mode or duration of contract of independent power producers in power sector planning in Indonesia. In particular, an approach is developed to assess the contributions of supply- and demand-side effects to the changes in CO2, SO2 and NOx emissions from the power sector due to changing of operating mode or duration of contract of independent power producers. The results show that the supply side effect would increase the CO2, SO2 and NOx mitigations, however, the demand side effect would act in the opposite direction. The results also show that the CO2, SO2 and NOx emission mitigations would increase if the operating mode or duration of contract is increased from 60 to 80% or from 5 to 15 years respectively.

Masafumi Miyatake

Papers

Design of Optimal Train Speed Profile for PMSM Railway Traction System Using Dynamic Programming with MTPA Control Method

1A11 Methods of modeling and calculation of a feeding circuit for evaluating energy efficiency and operational robustness by train traffic simulation(Electrical-Power)

3E24 Rational placement of charging-station for Lithium-ion battery onboard of rail vehicles(Electrical-Vehicle)

A Stand-Alone One-Stage Power Conditioner Using Time-Sharing Sinewave Tracking Bypass Diode Assisted- Boost Soft Switching Chopper and PWM Inverter

Supply- and Demand- Side Effects of Power Sector Planning with Independent Power Producers: A Case of Indonesia