M. Tariq Iqbal

A permanent magnet generator with PCB stator for low speed marine current applications

This paper introduces the design and development of a novel axial-flux permanent magnet generator (PMG) using a printed circuit board (PCB) stator winding. This design has the mechanical rigidity, high efficiency and zero cogging torque required for a low speed water current turbine. The PCB stator has simplified the design and construction and avoids any slip rings. The flexible PCB winding represents an ultra thin electromagnetic exciting source where coils are wound in a wedge shape. The proposed multi-poles generator can be used for various low speed applications especially in small marine current energy conversion systems.

Grid connected energy storage system to profit from net-metering and variable rate electricity

This article analyses an application of a grid connected battery-based storage system to profit from net-metering and variable rate electricity available in some Canadian provinces. It is possible for customers to manage their energy consumption in response to energy prices variation over a day by integrating an energy storage system in a home. In the present analysis a prototype of the battery based energy storage system has been designed and implemented. A control algorithm has been proposed to investigate the impacts of different charging and discharging scenarios. The proposed control algorithm is able to control the battery energy system as required in a typical home. Sizing and cost calculations indicate that such a system can profit from variable rate electricity. The outcome of this case study can be extended and used by residents who are interested to generate profit from variable rate electricity.

Performance evaluation of a hybrid wind-diesel-compressed air energy storage system

One of the main concerns of hybrid power system is the fluctuation of voltage and frequency of the system due to variation in the load and renewable power. A number of different types of energy storage techniques, which are theoretically and operationally available, have been proposed to remedy such fluctuations. One long-term storage option is compressed air. In this paper, the effects of the working pressure and system design of a typical compressed air storage system on the overall performance of a hybrid system is investigated. The model of a hybrid wind-diesel-compressed air generating system is developed and simulated using MATLAB. It is shown that the energy storage system and the proper sizing of the same play a vital role in increasing the renewable energy penetration.

An embedded DSP-based Frequency Response Analyzer for Fuel Cells Monitoring and Characterization

This paper presents an embedded frequency response analyzer (EFRA) for Fuel Cells (FC) based on a low-cost digital signal processor (DSP). Frequency response analysis technique provides valuable information of different electrochemical processes that occur inside the FC. The small size and low power consumption allows this special device to be embedded into the FC controller or the power conditioning stage. The system is capable of measuring automatically the frequency response of the FC at different operating points, even when the FC is operating with load. These measurements can be used to characterize the FC at design stage and to perform on-line monitoring of the FC state during continuous operation. The proposed instrument uses the lock-in amplification technique, which allows very accurate and precise measurements even in the presence of high noise levels. The proposed hardware and signal processing technique are described in this paper including experimental result of a 1.2kW proton Exchange Membrane Fuel Cell (PEMFC) system.

A new approach to minimize the cogging torque of axial flux pmg for under water applications

The rotor of a typical water current turbine rotates below 100 rpm. In conventional hydro installation the generator is coupled to the turbine via a gear box, so that it can typically rotate at a speed of 1500 or 1800 rpm. The water current turbine can be simplified by eliminating the gear box and by using a low-speed generator, the rotor of which rotates at the same speed as the rotor of the turbine. The main design challenge for a direct driven Permanent Magnet Generator (PMG) is to minimize the cogging torque. Cogging torque is an inherent characteristic of PMGs and is caused by the geometry of the generator. In this paper a new approach to minimize the PMG cogging torque is proposed. Basic design of a low cogging torque generator is also provided.

Grid Impact of a 5.25 MW Wind Farm near St.Anthony, Newfoundland

St. Anthony is a town on the northern peninsula of Newfoundland. This region is connected to the Newfoundland island grid through a 248 km transmission line and has one of the best wind resources in Canada. In this paper, the wind speed data of the region as well as the sizing of a grid connected wind farm at Cape Norman near St. Anthony are presented. The dynamic model of the system, wind farm and the long transmission line are included in the paper. The dynamic model is simulated using Matlab/Simulink to determine system voltage and frequency variations. The study indicates that a 5.25 MW wind farm in this region will lead to a local voltage variation of about 7% and frequency variation of 0.7 Hz for a typical wind speed variation in that region. Such variations in a remote location like St. Anthony are considered acceptable.

Solar Water Pumping System Control Using a Low Cost ESP32 Microcontroller

This paper presents a low cost automated solar water pumping system for irrigation in developing countries. The programmed sensor module detects the temperature, humidity, soil moisture level and sends the information to ESP32 microcontroller. A water level sensor also observes the water level and sends the data to the microcontroller unit. Based on the information and boundary conditions, the micro controller decides either to start or to stop the pump motor. This paper also describes how to decide soil moisture limits for a particular type of soil. The ESP32 microcontroller also sends results to the web server so that the user can see that. The user can operate the irrigation system far from the field by a simple click on a cellphone. A manual ON/OFF system is also incorporated into the proposed design.

Dynamic Modelling of a Solar Water Pumping System with Energy Storage

This paper describes the dynamic modelling of a system used for extraction of groundwater for irrigation using an alternative source of energy. The system is designed based on data of an existing project in Lalmonirhat, Bangladesh. The system comprises a 38.4 kWp solar photovoltaic array, inverter, AC motor, and pump set, which can discharge a maximum of 1,930 m3 of water per day. MATLAB simulation is performed with two types of energy storage system: (i) electric energy using a battery bank and (ii) stored water in a large water tank. A large battery bank and a transformer are needed in the former one, which turns out as a costly solution. The latter one requires a boost converter and a large water tank to store around 2,000 m3 of water, which is also a costly solution. A combination of both systems yields an efficient and economical solution. The effectiveness of these three systems is compared with conventional diesel engine system.

Dynamic Modeling and Simulation of an Isolated Hybrid Power System in a Rural Area of China

In some rural areas in the northwest of China, people are suffering from not only the voltage drop due to long distance transmission but also the power outages due to remoteness and poorly maintained grid. In recent few years, the price of solar energy has been reduced drastically every year in China due to the government policy on renewable energy. In the near future, isolated hybrid power systems for home use could be affordable and used by residences in these rural areas. Thus, it is necessary to design a hybrid power system based on local load and weather condition to check system feasibility and expected performance. It includes load simulation, system sizing, and dynamic system modeling and simulation. This paper firstly introduces current development of renewable energy in China and then goes through the sizing, modeling, and simulation of the system design for a typical remote home in China and finally discusses the system’s availability based on the simulation results. In this paper, the NASA website is the source for weather data, and BEopt is used to generate load data. During system modeling, the MPPT algorithm is much simpler designed than the complex incremental method. A soft starter is adopted with the diesel generator for stability. The charge controller of the battery storage provides external command to the MPPT and diesel PID controller to prevent the battery storage from overcharging. The rms value of the fundamental load voltage is used in the voltage control loop of the inverter.

Modified Droop Method Based on Master Current Control for Parallel-Connected DC-DC Boost Converters

Load current sharing between parallel-connected DC-DC boost converters is very important for system reliability. This paper proposes a modified droop method based on master current control for parallel-connected DC-DC boost converters. The modified droop method uses an algorithm for parallel-connected DC-DC boost converters to adaptively adjust the reference voltage for each converter according to the load regulation characteristics of the droop method. Unlike the conventional droop method, the current feedback signal (master current) for one of the parallel-connected converters is used in the inner loop controller for all converters to avoid any differences in the time delay of the control loops for the parallel-connected converters. The algorithm ensures that the load current sharing is identical to the load regulation characteristics of the droop method. The proposed algorithm is tested with a mismatch in the parameters of the parallel converters. The effectiveness of the proposed algorithm is verified using Matlab/Simulink simulation.