Showing papers presented at "International Conference on Power Electronics Systems and Applications in 2020"

Generalized Circuit Averaging Technique for Two Switch DC- DC Converters

Abstract: Cuk and SEPIC are some of the important DC-DC converters used for charging batteries. In this paper, a generalized circuit averaging technique is employed for Cuk and SEPIC converters. The derived equations are used to obtain the frequency response of open loop transfer function. The ratio of perturbed output voltage to duty cycle (C vd ) is simulated using LTSpice software package. The derived averaged models of the converters aids in faster and simpler simulation. The behavior of the converters in CCM and DCM was also simulated. The derived expressions can be generalized to power converters with two switches.

A New 7-Level Inverter for Active and Reactive Power Compensation Using PEV in Grid-Connected Applications

Abstract: Typically, conventional multilevel inverters (MLI) have the disadvantage of being unable to step up the input voltage. Therefore, one type of three phase MLI with boost capacity is proposed. The proposed three-phase inverter is capable of generating seven levels (0, 1V dc, 2V dc, 3V dc, −1 V dc, −2V dc, −3V dc), while only one DC source and five capacitors are required for the three phase configuration. To facilitate analysis, a phase position pulse-width-modulation (PD-PWM) strategy is applied to control switches. And suitable switching modes are also selected to balance the voltage of capacitors. In order to verify and validate the proper operation of the proposed circuit configuration and the ability using plug-in electric vehicle (PVE) battery into grid, the system is simulated in PLECS. The results of simulation are provided to validate the feasibility of the proposed inverter.

Comparative Studies on the Primary-Side Frequency and Phase Shift Control for Series-Series Compensated Inductive Power Transfer

Abstract: Since the Society of Automobile Engineers (SAE) launched the guideline J2954 for wireless battery charging of electric vehicles (EVs), research activities on inductive power transfer (IPT) or wireless power transfer (WPT) in EVs are intensified over the last few years. The guideline J2954 calls for an operating frequency around 85 kHz and power at four levels. In this paper, both frequency and phase shift control, are designed by controlling the front-end inverters to achieve constant current (CC) and constant voltage (CV) control of Li-ion battery loads in a power-scaled-down (i.e., 200 W) IPT system. Simulation results using PSIM9.0 have verified the effectiveness of both control strategies.

The Duality of Inductive Power Transfer and Capacitive Power Transfer

Abstract: Both inductive and capacitive wireless power transfer can be used for the charging of electric vehicles theoretically. In this paper, the mutual-capacitance coupling model of capacitive power transfer is proposed by analogy with the mutual-inductance coupling model of inductive power transfer. In single input single output (SISO), multiple input single output (MISO), and single input multiple output (SIMO) wireless power transfer systems, it shows that inductive power transfer and capacitive power transfer have duality in circuit topology and circuit equation.

Design and Optimization of a Bilayer Quadrature Double-D Coil for Electric Vehicle Wireless Charging System

Abstract: This paper proposes a wireless power transfer (WPT) system with dual transmitting coils and dual receiving coils based on a pair of bilayer quadrature double-D (BQDD) coil for wireless charging of an electric vehicle (EV). And presents a parameter design method of the system. The magnetic coupler composed of a pair of BQDD coil has the following characteristics: 1) Mutual decoupling between transmitting coils and receiving coils; 2) It can be applied to a WPT system with dual transmitting coils and dual receiving coils to improve power capacity; 3) High power density. Firstly, the circuit model of the WPT system with dual transmitters and dual receivers is established based on the double-sided LCC compensation network, and the expression of the output power is derived. Then, according to the specific requirements, the parameters of the magnetic coupler and the circuit are analyzed and optimized. Then, with the help of Simulink and COMSOL simulation, the effectiveness of the parameter design method is verified. Finally, the comparison with the conventional magnetic coupler verifies that the BQDD coupler has a higher power density.

Energy Storage, Fuel Cell and Electric Vehicle Technology

Abstract: The energy storage components include the Li-ion battery and super-capacitors are the common energy storage for electric vehicles. Fuel cells are emerging technology for electric vehicles that has promising high traveling distance per charge. Also, other new electric vehicle parts and components such as in-wheel motor, active suspension, and braking are emerging recently to upgrade the vehicles' performance. In this tutorial, the above topics are discussed and an outlook on future vehicles is highlighted. The tutorial paper is suitable for researchers or engineers with a deep knowledge of electric vehicles and is also suitable for someone new to the field.

Communication Infrastructure for E-Mobility Charging Stations V2G Applications

Abstract: This paper main goal is to analyze the ISO 15118 standard used for E-Mobility charging applications, identifying advantages and disadvantages from the infrastructure used in the market and to propose a new strategy aiming to adapt metering infrastructures for vehicle-to-grid energy trading platforms. The idea of exchanging energy with the grid is raising awareness among end-users. While consumers start to produce their own energy and decentralized generation is emerging as a new paradigm for the electricity market, flexible-loads such as e-mobility charging platforms are also on the rise, which may cause a negative impact in the long term, considering the big increase in the demanded amount of energy. Therefore, not only new algorithms and strategies need to be taken into account in order to mitigate the drawbacks e-mobility may have in the near future, but also fast and reliable communication protocols need to be addressed, since they form the key infrastructure for real-time data to be transported, stored and analyzed. The unfolding considers a pure-theoretical approach on charging stations infrastructure, with a clear emphasis on communication protocols used nowadays. Followed by a innovative proposal of using sub-l (GHz) radio signals building a distributed mesh-network for data acquisition in noisy environments, aiming to propose a bi-directional communication framework between vehicles, users and the grid. Conclusions are drawn, emphasising in the advantages and disadvantages of both proposals, as well as analyzing the main requirements for ensuring a feasible communication infrastructure for vehicle-to-grid integration.

A Distributed Transaction Mechanism for Electricity Market with Electric Vehicles and Blockchain

Abstract: As distributed transactions become more and more mature, such as peer-to-peer (P2P), the widespread application of distributed transactions not only requires fair and open transaction process, but also has as little impact on the main network as possible. This paper considers an energy matching model, which includes two parts. The first part is a kind of new auction, in which participants can clearly aware of competitive pressures because of current or historical data in blockchain. The second part is an interaction between charging station operator and unmatched participants in the first part. Cases have been studied to demonstrate the effectiveness of this distributed transaction.

Key Technologies and New Developments of Stationary/Dynamic Wireless Power Transfer

Abstract: In the last few decades, wireless power transfer (WPT) is widely used in various applications due to its safety and reliability, and has become the trend of power supply in the future. However, there are still some challenges and problems to be solved in practical applications, such as large current stress with single phase-shift control, multiple outputs for driving multi-string LEDs, power pulsation phenomenon or power null phenomenon in dynamic WPT (DWPT) system. This tutorial will introduce these problems and present the corresponding solutions in detail.

Study and Development of Mixed Repurposing EV Battery System for Stationary Energy Storage Applications

Abstract: This paper presents a case study of developing a stationary battery energy storage system (ESS) with a combination of used batteries from different electric vehicles (EVs), The batteries having nonidentical specifications, dismantled from two models of retired EVs with varied conditions, have been characterized. The state of health and the expected electrical performance of these repurposed batteries from EVs are analyzed and compared. A modular battery ESS with dual feed configuration is developed to strike a balance between reliability, performance and the cost of implementation. The modular approach allows flexibility in capacity and voltage level manipulation, as well as mitigates the efforts of battery replacement. The construction and key components in the systems are illustrated and explained. A simulation study has been performed which explores the effects of varied battery profiles and combinations to system performance. This work provides insights on designing and operating sustainable stationary ESS with mixed repurposed cells.

New Modelling and Control Techniques for Wireless Power Transfer (WPT) Systems

Abstract: The operating conditions of WPT systems commonly result in coil misalignment and, thus reduce mutual inductance (M), between transmitting and receiving coils. As a consequence, the coil inductances and load impedance reflected to the primary side will be changed, detuning the resonant WPT system and limiting its power transfer capability, which in turn leads to excessive apparent power draw and low system efficiency. This paper presents the concepts of a new technique for modelling WPT systems that can be simply modified to investigate different types of compensation circuits. The concepts of an optimal control strategy are also presented that allows for regulated power transfer with impedance matching for maximum efficiency, regardless of large variations in M and load. The new modelling technique is used to investigate the performance of WPT systems implemented with two basic types of compensation circuit and an optimal control strategy. The results for a bi-directional WPT system demonstrate applicability of the proposed modelling and optimal control techniques.

Solar Electric Boat Development Programme

Abstract: Solar boat for entertainment and short distance traveling is examined in this paper. The maximum power point tracking, battery management system, solar power charging, and overall system design are proposed. The boat is designed for low power and cost side water travelling and no wave and tidal issues. The boat is then based on low power and low cost design. The boat has been verified by practical test and the performance is highly satisfactory. The project is to promote green transportation and green entertainment and is a good education program development.

A Cascaded Flying Capacitor Multilevel Inverter with Double-Boost Voltage Gain and reduced capacitor count for solar PV systems

Abstract: Fed by a mass of photovoltaic (PV) panels in series, the traditional buck-type flying-capacitor (FC) multilevel inverter has poor operational reliability in grid-connection application. In order to obtain a step-up output voltage, a novel five-level voltage source inverter is proposed by cascading two FC cells. The proposed inverter reduces the number of capacitors compared to the traditional buck-type topology with the same number of voltage levels. Moreover, the voltages of the capacitors can be self-balanced without using any other active-balancing strategies. Descriptions and theoretical analyses of the proposed inverter are given, followed by simulation results verifying its feasibility.

Optimization of Electric Bus Charging Station Considering Energy Storage System

Abstract: Electric buses have become an ideal alternative to diesel buses due to their economic and environmental benefits. Based on the optimization problem of electric bus charging station with energy storage system, this paper establishes a daily operation model of charging station to minimize the charging and discharging cost and the battery loss cost. Then, the day ahead charging and discharging strategy of the charging station is analyzed by particle swarm optimization algorithm (PSO) while meeting the travel needs of the electric bus. In addition, the simulation results show the feasibility and superiority of the strategy, and the sensitivity analysis of energy storage system with different charge-discharge powers is shown by the case study.

Generalized Hamiltonian Energy Modeling Method for Wireless Power Transfer System

Abstract: Wireless power transfer (WPT) system is a typical multi-mode, nonlinear, uncertain, high-dimensional system, and system modeling is relatively difficult. This paper proposed an energy modeling method based on Hamilton realization to overcome the limitations of traditional modeling and analysis methods due to system complexity. In this paper, a generalized Hamilton energy realization model of a capacitive power transfer (CPT) system based on double-sided LC-compensated network is established to study the property of the model specification characteristics. From the energy analysis of CPT systems, explaining the dynamic energy changing principle of the electromagnetic conversion process and revealing the principle of wireless power transmission. The simulation results show relations between the energy invariance of the stored energy, and verifies the accuracy of the Hamilton energy model.

Torque Ripple Minimization of IPMSM Drives With Current Injection Derived from Torque Error

Abstract: In this paper, a method of harmonic current injection used to minimize the torque ripple of interior permanent magnet synchronous machine (IPMSM) is proposed. Different from the existing schemes of generating compensating current which use torque sensor or look up table, the scheme proposed to get the compensating current by a high-fidelity torque model. A smoother torque will be obtained by adding this compensating current to current loop, if the current loop has enough bandwidth to achieve accurate tracking. In order to achieve better current following effect and realize the dynamic operation of the motor, this paper choses the angle-based repetitive controller, which memory the torque according the rotor position and the memory doesn't need to resized even if the speed change. The simulation results show that the method can achieve better torque ripple suppression effect when the speed and torque command change.

Analysis of NARXNN for State of Charge Estimation for Li-ion Batteries on various Drive Cycles

Abstract: Electric Vehicles (EVs) are rapidly increasing in popularity as they are environment friendly. Lithium Ion batteries are at the heart of EV technology and contribute to most of the weight and cost of an EV. State of Charge (SOC) is a very important metric which helps to predict the range of an EV. There is a need to accurately estimate available battery capacity in a battery pack such that the available range in a vehicle can be determined. There are various techniques available to estimate SOC. In this paper, a data driven approach is selected and a Nonlinear Autoregressive Network with Exogenous Inputs Neural Network (NARXNN) is explored to accurately estimate SOC. NARXNN has been shown to be superior to conventional Machine Learning techniques available in the literature. The NARXNN model is developed and tested on various EV Drive Cycles like LA92, US06, UDDS and HWFET to test its performance on realworld scenarios. The model is shown to outperform conventional statistical machine learning methods and achieve a Mean Squared Error (MSE) in the 10 −5 range.

An Investigation of Compensation Networks for Three-coil Wireless Power Transfer

Abstract: Wireless power transfer (WPT) can power loads over large air gaps with relatively high efficiency, offering an innovative and convenient charging way. Especially, three-coil WPT shows the superiority, namely, the extended transmission distance with high efficiency. However, compensation networks in three-coil WPT still necessitate investigation. In this paper, three compensation topologies including S-S-S, S-S-P and N -S-S are investigated. Some important characteristics including load-independent constant voltage (CV), load-independent constant current (CC) and zero voltage switching (ZVS) are concluded and compared among different topologies. Detailed design procedures of compensation networks based on three-coil couplers are demonstrated. The fundamental analysis, coil design, compensation topologies and experimental verification are all presented and discussed in this paper.

Modeling and Analysis of the Flux-Weakening Range of Interior Permanent Magnet Synchronous Machines with Segmented Permanent Magnets

Abstract: To improve the flux-weakening characteristics, Interior Permanent Magnet Synchronous Machines with Segmented Permanent Magnets (Segmented IPMSM) are investigated in this paper. At first, an improved magnetic circuit analysis model is deduced to explain the flux-weakening mechanism of Segmented IPMSM. Then, four different rotor topologies are obtained through designing the number of segmented permanent magnets and the shape and placement of the segmented permanent magnets in rotor. The detailed comparisons of characteristics such as d-axis inductance and flux-weakening speed-expansion are presented by Finite Element Method. The results illustrate flux-weakening capability is improved by magnet segmentation with iron bridges.

Adaptive Control of Quadrotor UAV Based on Arduino

Abstract: This paper mainly studies the control of the sensors of the quadcopter unmanned aerial vehicle (UAV) based on the serial-stage PID controller. Firstly, by modeling the dynamic model of the drones, the control method of the quadcopter unmanned aerial vehicle is illustrated. After that, the design requirements for the parameters and precision of the sensors and executors needed in this design are put forward, and the device comparison is carried out. Finally, a system design scheme with four brushless DC motor speed control is given, and the scheme is tested.

State-of-Charge Estimation of Lithium-ion Batteries Using the Nesterov Accelerated Gradient Algorithm Based Bi-GRU

Abstract: Electric vehicles have been developing rapidly in recent years, the State-of-Charge (SOC) of lithium-ion batteries can related to the safety and reliability of electric vehicles. With the development of the field of machine learning, data-driven methods often use machine learning platforms to obtain the relationship between battery measurement signals and SOC from them to achieve accurate estimation of SOC. To further explore the potential of machine learning platforms in SOC estimation, an improved model using the Nesterov Accelerated Gradient (NAG) algorithm based Bidirectional Gated Recurrent Unit (Bi-GRU) network is put forward in this paper. Furthermore, a well-recognized lithium-ion battery dataset from University of Maryland is applied to evaluate the validity and quality of the established NAG based Bi-GRU model. Finally, the results demonstrate that the established NAG based Bi-GRU model have a preferable precision of the SOC estimation at various ambient temperature, compared to state-of-the-art data-driven estimation methods.

A Dynamic Model Based Method for Evaluating the Operation State of Provincial Power Grid Company

Abstract: With the reform of the electric power system, the rural power supply enterprises, which were previously independent, have been merged into provincial power supply enterprises, which will affect the investment and planning in the operation and management of the provincial power grid companies. The writers studied the policies about rural power supply enterprise merger, built a mathematical model for assessing the provincial power grid companies operation. Combine the influence with income and supervision, the authors propose a dynamic evaluation method based on system dynamics to evaluate the operation status of rural power supply enterprises after they are merged into provincial power grid companies. The authors set the method as a period of three years, the relationship between the combined operation and investment capacity of rural power enterprises is further quantified by the multi-time model. The method is verified by case simulation and sensitivity analysis.

Research on Grouped Optimization Control Strategy for Large DFIG Based Wind Farm

Abstract: This paper proposes a grouped reactive power optimization control strategy to maximize the output active power of large doubly fed induction generator (DFIG) based wind farm (WF). The wind turbines (WTs) in the WF are grouped to relieve computation burden. The reactive power requirements of power grid are distributed among groups by the particle swarm optimization (PSO) algorithm, and reactive requirements in each group are distributed by the proportional control strategy. The simulation of WF case studies presented, based on various wind powers and reactive power dispatching instructions (RPDIs) of power grid, demonstrate that the proposed grouped technique allows for a larger the output active power of WF while tracking the RPDI of the power grid, by distributing the reactive power among WTs rapidly.

Research on Constant Voltage Output Optimization Method for EV Dynamic Wireless Charging System

Abstract: In the dynamic wireless charging system for EVs, the cascaded multi-stage transmitting rail is widely used due to its unique advantages. Combined with the LCC-S constant voltage output compensation topology, the system control method is also simplified. However, the primary side structure of this method is pretty complicated and the number of components is large. The cost is very expensive in long-distance applications. In response to this problem, this paper proposes a method of adding a relay coil to the secondary coil. By setting the transmitting, relay and receiving coils as series compensation, the primary side structure is simplified while maintaining the dynamic constant voltage output of the system and saving the cost of components. Theoretical analysis and simulation results verify the feasibility and superiority of this method.

Electric Antilock Braking Systems for Electric Vehicles

Abstract: Electrohydraulic antilock braking system (ABS) is one of important components in current commercial road vehicles. It provides safe protection and minimizes braking distance. This study focuses on the electric or electromechanical antilock braking system for electric vehicles, which mainly includes the electromechanical brakes (EMBs) and the ABS methods. Taking into account the EMB topologies, the electromechanical brakes are classified into four types. The status of the research on four EMB topologies is surveyed. Furthermore, four EMB topologies are evaluated according to the performance and practicability. The ABS methodologies are classified into four types. The status of the research on four ABS methodologies is investigated. In addition, the performance and practicability of ABS methods are defined as the evaluation indices, to evaluate the cited ABS methods. The challenging issues in research on EMBs and ABS methods are also addressed.

A Cross Double-D Coil for Electric Vehicles Dynamic Wireless Transfer System to Reduce Output Power Pulsation

Abstract: This paper proposes a cross double-D (CDD) coil for an electric vehicles dynamic wireless power transfer (EV-DWPT) system, which can achieve steady output power and reduce magnetic leakage. This magnetic coupler consists of a cross snakelike Double-D (DD) coil-like sinusoidal variation in the part of the transmitter and a conventional DD coil in the part of the receiver. The working principle of the cross DD coil is analyzed in this paper. Meanwhile, the whole magnetic coupler parameters and circuit parameters are presented. The simulation results have been obtained by establishing the finite element analysis (FEA) model and circuit topology, which validate this structure can reduce output power pulsation.

Design and evaluation of a phase-shift full-bridge converter for electrical vehicle

Abstract: A high frequency converter with maximum 150A/2.5kW output is designed and evaluated in this paper. This converter consists of three parallel PSFB modules. The main components for each module are designed. Small signal model for single module is established and a digital peak current mode control is designed and implemented. Finally, a 2.5kW prototype with up to 150A output current is built. The experimental results demonstrate well performance of the prototype and confirm of the validity the design.

A Simple Approach to Improve the Switching Performance of Cascode GaNFETs

Abstract: This paper analyses the switching performance of the cascode GaNFETs on Silicon substrates in three different PCBs using a double pulse test (DPT). A significant Vgs ringing is found during experiment. The source side parasitic inductance of cascade GaN with TO-247 package has been evaluated to cause significant gate voltage high frequency ringing. Moreover, reduction in Vgs high frequency ringing allows further reduction in input capacitance of the cascode structure. Which indicates a LV Si MOSFET with smaller input capacitance can be used in cascode GaNFETs. This enables faster switching transients and boosts the maximum switching frequency operation of cascode GaN devices, and thereby making use of the advantages that Gallium Nitride (GaN) brings. Method to reduce Vgs high frequency ringing is introduced in this paper. This enables stable switching transients and enhance the switching performance of cascode GaN devices, and thereby making use of the advantages that Gallium Nitride (GaN) brings. Simulation based on spice model is conducted for verification purpose.

Nano Bubble Technology for Future Water and Farm Applications Using Solar Power

Abstract: Nanobubble has a number of applications. It can convert the air bubble into Nano size so that it can provide a number of new applications. One of the good applications is the cleaning and also fish farming. The nano oxygen bubble enables a much better growth index for the fish farm. Experiment results have found that the growth rate of the nanobubble technology is substantial. The proposed development is to build an all-electric and green technology for the nano bubble generator. That is power by the photovoltaic system. A battery energy storage is used to make the system 100% renewable and external AC power is needed.

Modeling and Analysis of Fiber-reinforced Soft Bending Actuators

Abstract: Soft bending actuators can provide larger contact forces and bending angles if designed with fiber-reinforced structure. The research of fiber-reinforced soft bending actuators mainly focuses on experimental evaluations. However, theoretical analysis and modeling of the deformation and contact force are limited. In this paper, the deformation and the contact force of fiber-reinforced soft bending actuators are studied. The relationship between the number of winded coils as well as their pitch and the actuator's bending are analyzed. A nonlinear mathematical model of the soft bending angle driven by pressurized air, and the theoretical model of its contact force are proposed. To verify these theories, the finite element analysis (FEA) and experiments are conducted. The results prove that the fiber-reinforced structure significantly improve the bending behavior and the contact force of soft bending actuators.