Showing papers presented at "International Conference on Power Electronics Systems and Applications in 2009"

Electric Vehicle development: The past, present & future

Abstract: A vehicle is consider Green when it more environmentally friendly than the traditional petroleum combustion engine, in which includes any nontraditional vehicle like, HEV, Plug In, EV, Fuel Cell, Bio fuel etc. that improves fuel economy. The development of electric vehicle has been over a hundred years but failure to gain the public acceptance in various stages due to various reasons which explained. While EV was never mass produced, Hybrid electric vehicle gains the momentum in recent years. Ford has launched its second generation of HEV and GM also announced the debut of the Volt in 2010. Comparing to the regular HEV, Plug in is the new trend in hybrid auto development due to extend travel range in electrical mode and a possibility of a zero emission as long as travel distance is less than charging threshold. However, more recently, an electrification trend in automotive industry has been evolved and will revolutionize the industry. With the correct policy and government help and advancement of electric vehicle technology, the prospect of Electric Vehicle will be bright and the focus point of future development.

A novel outer-rotor permanent-magnet flux-switching machine for urban electric vehicle propulsion

Abstract: A novel twelve-stator-pole, twenty-two-rotor-pole (12/22) outer-rotor permanent-magnet flux-switching (PMFS) machine for electric propulsion in a lightweight electric vehicle is presented. Analytical equations are derived for the dimensioning of a 3-phase 5kW in-wheel motor. Optimisation techniques are employed to maximise the performance of the machine. The validity of the analytical equations is verified by finite element analysis (FEA). The results show that the PMFS machine combines the key advantages of the PM machines and the switched reluctance machine, and thus demonstrate the viability of the proposed machine as a suitable candidate for in-wheel electric propulsion.

The topologies of white LED lamps' power drivers

Abstract: This paper demonstrates power electronic drivers for white LED lamps. Due to some obvious features such as high luminous efficiency, low-loss energy, long life, safety, green, and so on, it's expected to replace conventional lamps including incandescent, halogen and fluorescent lamps at least in some general illumination application within the near future. It's always used in automotive fields. Innovative design in driver circuits of white LED lamps with respect of functionality, efficiency, cost, size and reliability enables the successful introduction of new LED based lighting products. First of all, it describes LED's characteristics briefly which include electrical character, driver requirement, luminous characteristic, thermal performance and package structure. In the second part, a series connection of single LED cells is presented in detail. For efficiency reasons, white LED lamps can not be droved via series resistor, but need PWM models with current control. In the third part, different standard DC-DC converter topologies are discussed which can be adapted to feed a constant current into a LED load. Hence, roughly, it consists of two general types which named non-isolated driver and isolated driver separately. This paper will introduce more detailed classifications. It's convenient to choose proper driver circuit and suited components through the comparison between the topologies of this paper. In addition, PFC(Power Factor Correction) circuit is also involved in high power factor. Finally, some hot spots in white LED lamps fields are focused on.

Recent development on electric vehicles

Abstract: This paper provide an overview of the recent work of electric vehicle in the region. The paper describes the development and the comparison of different part of components. The major components in battery technology, charger design, motor, steering and braking are examined. The paper finally shows some electric vehicle prototype as a conclusion of the papers.

Battery management system and control strategy for hybrid and electric vehicle

Abstract: Battery management system (BMS) is an integral part of any electrical vehicle, which ensures that the batteries are not subjected to conditions outside their specified safe operating conditions. Thus the safety of the battery as well as of the passengers depend on the design of the BMS. In the present work a preliminary work is carried out to simulate a typical BMS for hybrid electrical vehicle. The various functional blocks of the BMS are implemented in SIMULINK toolbox of MATLAB. The BMS proposed is equipped with a battery model in which SOC is used as one of the states to overcome the limitation of stand-alone coulomb counting method for SOC estimation. The parameters of the battery are extracted from experimental results and incorporated in the model. The simulation results are validated by experimental results.

Construction, operation and control of a laboratory-scale Microgrid

Abstract: To provide a test facility for possible demonstrations of advanced distributed generation system integration strategies, a single-phase laboratory-scale Microgrid system is set up. Two distributed generators are included in this Microgrid, a photovoltaic simulator and a wind turbine simulator. Both of them are connected to the AC grid via flexible power electronic interface respectively. For stable collaborative operation, a battery energy storage interfaced with a bi-directional inverter is necessary in this Microgrid. In the grid-connected mode, both the distributed generators converters and the bi-directional inverter are the grid-following unit. While switching from grid-connected mode to islanded mode, the bi-directional inverter is setting the voltage and frequency of the Microgrid through absorbing or releasing energy. The operation experimental results show that the laboratory-scale Microgrid system can operate in grid-connected or islanded mode, with a seamless transfer from one mode to the other, and hence increase the reliability of energy supplies.

Experimental investigation of in-wheel switched reluctance motor driving system for future electric vehicles

Abstract: This paper presents an experimental direct driving system with in-wheel switched reluctance motor (SRM) for electrical vehicle (EV). The integrated EV direct driving system includes three main parts: the SRM model, driving circuit and control unit. The proposed 8/6 SRM is a novel motor with high performance; the specified external rotor type fits the requirement of in-wheel EV for saving space. The driving module consists of four independent drivers, is controlled by the micro-controller, DSP. The detailed hardware installment is presented to realize the EV direct driving system, with the block diagram to show the design of the driving system. Control flow of the specified system is introduced to describe the control procedure; various control methods are proposed and studied to verify the performance of SRM and the driving system. Speed control and constant torque/constant power control are implemented with PI control and hysteresis loop control, to test the speed response and reliability of the direct driving system. An experimental direct driving system is developed; the experimental results are obtained to verify the performances of the EV driving system.

Fuzzy PID controller used in yaw system of Wind Turbine

Abstract: Yaw system plays an important role in wind turbine generator because of the direction and intensity of wind is time-varying. Because the model of yaw system is difficult to be set up and some parameters of controller are uncertain. General PID controller is not suit for all operation scope. This paper presents a fuzzy PID controller to deal with the control of yaw system with disturbances and uncertain factors. To provide a better tracking effect for system, an approach of fuzzy PID rule is adopted, which PID parameter is adjusted by fuzzy rule when Wind Turbine Generator is operating. Simulation results show that using the present scheme combining conventional PID with fuzzy control, the yaw system can posses better tracking characteristics than PID controller does.

Review on the configurations of hybrid electric vehicles

Abstract: This paper presents an introduction to hybrid electric vehicles, the commonly used configurations of the driving chains, the comparisons among these configurations, and then finally the possible developments of hybrid electric vehicles in the near further. Plug-in hybrid electric vehicles are also included in the discussion.

Towards a Brain-Computer Interface based control for next generation electric wheelchairs

Abstract: This paper presents an idea of building a Brain-Computer Interface (BCI) based control for next generation electric wheelchairs. The aim is to explore the area of research on BCI based control to potentially develop a next generation of electric wheelchair which is able to benefit to paralyzed patients. This EEG interfacing development controls a wheel chair through a skid steering method. The mechanical part including the conventional steering can be eliminated. It also uses differential speed that controls the propulsion and turning. The system is neat, low cost and high dynamic performance; it can be used for stoke patent or disabled patents.

The realization of control subsystem in the energy management of wind/solar hybrid power system

Abstract: In this paper, the hardware realization of the energy management and control subsystem of a grid-connected wind/solar hybrid power system has been introduced. The hybrid power system is based on multi-agents theory, so the control subsystem is regarded as an agent. It is composed of programmable logic controller(PLC), human-machine interface (HMI), grid-connected control module, AC multi-function electric power meters, DC electric power meters, RS485/TCP converter etc., to control and manage the operation of multi-source, such as power grid, wind turbine generation, solar photovoltaic, storage batteries and loads, also to acquire data and communicate with others. In this paper we put the emphases on its hardware, communication and how to meet its requests and functions. Experiments show that this system is competent for both grid-connected mode and stand-alone mode.

A rotary-linear switched reluctance motor

Abstract: This paper aims to investigate, develop and fabricate a direct-drive, rotary-linear motor based on switched reluctance (SR) principle. The proposed system has the advantages of mechanically robust, simple structure and operation under hostile working environment. The finite element analysis (FEA) provides an intuitive and precise analysis of the proposed motor. The proposed machine is expected to find applications in high-precision manufacture field.

The performance research of large scale wind farm connected to external power grid

Abstract: At present, the wind power generators widely used in China are the squirrel cage induction generators(SCIG). With the rapid increase in penetration of wind power in power systems, the dynamic influence of a large wind farm on power systems is becoming an important issue for integration and operation of wind farms. So grid codes require that all new installed WTGs should have the capability of Fault Ride Through (FRT) or Low Voltage Ride Through (LVRT). This capability means that wind generation should have the ability to remain connected during faults (outside their protection zone) and voltage dip conditions within certain limits. Based on the appropriate wind farm models, the dynamic performance of wind farm during faults and the effect of FRT with Static Var compensation(SVC) equiped is researched. Furthermore, the effect of FRT when doubly-fed induction generators(DFIG) connected in wind farm was researched. These models of wind farm were developed and compared by simulation studies in the PSCAD/EMTDC environment under different wind fluctuation conditions as well as gird fault conditions, which took Nanao wind farm connected to the Shantou power grid of Guangdong Province, China as an example. The simulation results showed that SVC can provide fast dynamic reactive power support, DFIG be able to provide reactive power support according to the requirement reactive power value of FSIG terminal very well.

FPGA-based DPWM for digitally controlled high-frequency DC-DC SMPS

Abstract: Digital pulse-width modulator (DPWM) is known as the critical module in digital controller application for high-frequency switching mode power supply (SMPS). This paper presents a new Hybrid DPWM architecture operating at high frequency with high resolution. The proposed DPWM takes advantage of the phase-shift function of Digital Clock Manager (DCM) in FPGA, and combines a counter-comparator with a digital dither block. To verify the proposed DPWM, an 11-bit prototype DPWM is implemented on a FPGA-based digitally controlled high-frequency buck converter. Experimental results with constant switching frequency up to 2MHz validate the functionality of the proposed DPWM. This hybrid architecture can operate at high switching frequency while reduce clock frequency so as to save power consumption.

Study of motoring operation of in-wheel switched reluctance motor drives for electric vehicles

Abstract: Based on the requirements of electric vehicles on electric motor drives, this paper presents three criteria to evaluate motoring operation of in-wheel switched reluctance motor drives for electric vehicles. They are the average torque, the average torque per rms current, and torque smoothness factor. They indicate the motoring torque, copper loss and torque ripple, respectively. The model of motoring operation under the current hysteresis control is developed to investigate the effects of the turn-on angle, the turn-off angle, and the current reference on these criteria. The simulated and measured current waveforms verify the proposed model. The simulated results show that the turn-on angle and the turn-off angles have considerable effects on motoring operation of switched reluctance drives. The optimal turn-on angle and the optimal turn-off angle can be optimized in order to maximum the average torque, the average torque per rms current, or the torque smoothness factor. In addition, the larger current reference results in the larger average torque, average torque per rms current and torque smoothness factor. Thus, this study is helpful for developing new control method to implement the best motoring operation of in-wheel switched reluctance motor drives in electric vehicles.

Cooperative reinforcement learning algorithm to distributed power system based on Multi-Agent

Abstract: With the development of renewable energy technology, the distributed wind-PV power system has a wider application. This paper proposes a distributed wind- PV power system based on Multi-Agent, whose main character is energy management, and describes the multi-agent cooperative reinforcement learning process using the joint action learning pattern as the cooperative strategy. The experiment of a distributed wind-PV power system shows the efficiency.

Efficient cooling of power electronics

Abstract: Power electronics devices are generating heat losses up to several hundreds of Watt/cm2. Chip shrinking causes a steady increase of heat to be dissipated. Intelligent solutions must be developed for better heat conduction from the chip to the ambient. The reduction of the thermal resistance of power modules is one of the challenges for the future. Decreasing the thermal resistance of the ceramic by use of thinner ceramics for the isolation substrates or ceramics with higher thermal conductivity is one alternative. Another possibility is direct liquid cooling of the isolation substrates either by using direct integration in a copper cooler system with micro-channels or by conventional soldering of the substrates to a liquid cooler with micro-channels. These solutions allow cooling with water temperatures up to 80°C so as not to exceed a chip temperature of 125°C. The usage of micro-channel copper structures improves the thermal resistance by 60% compared with a power module mounted onto a cold plate. Similar structured coolers are also used for cooling power laser diodes and processors.

Study and simulation of one bi-directional DC/DC converter in hybrid electric vehicle

Abstract: The paper first introduces the basic drive system of a kind of hybrid electric vehicle. It demands high power bidirectional flow capability, with wide input voltage range, and output voltage of energy storage devices such as super capacitors or batteries vary with the change in load. Then the selection and design of aforementioned converter is proposed in this paper. The converter which is like a half bridge topology, has high power flow capability and minimum device stresses that can suitably interface a super capacitor with the drive train of a hybrid electric vehicle. Furthermore, by comparing of the main characteristics and applications with some typical isolated bidirectional DC/DC converter, the proposed converter has low device rating and can be controlled by duty cycle and phase shift. At last, the most important characteristics of this converter is that it uses the transformer leakage inductance as the primary energy transfer element and control parameters, Simulation waveforms based on SIMetrix are given to demonstrate the goodness of this novel topology, and this converter is also suitable for high power application, in particular for controlling the charge-discharge of super capacitors or batteries that can be used in hybrid electric vehicle.

Heating performance improvement and field study of the induction cooker

Abstract: Magnetic induction heating is a common technique exploiting high frequency eddy current losses on metallic objects. In the past one to two decades, induction heating has been extended to the catering industry as induction cooker. Currently, the induction cooker draws more and more attentions as one of the popular kitchen appliances. This paper mainly investigates the magnetic field of induction cooker for improving its heating performance. Firstly, the magnetic field and heating performance of conventional induction cooker are analyzed. Furthermore, the problems associated with conventional induction cooker are identified. In order to overcome those disadvantages of traditional induction cooker, a novel coil format is proposed. Meanwhile, Finite Element Method is used to simulate and further analyze the behavior of the induction cooker. Finally, a prototype of the proposed induction cooker is built. The experimental results of conventional and the novel induction cooker are presented and compared. Both the simulation and experimental results indicate that the proposed solution can efficaciously improve the heating performance of conventional induction cooker.

Control technologies in distributed generation system based on renewable energy

Abstract: Greats efforts have been done to distributed renewable energy (RE) power system in latest years. This paper summarizes the research achievements of New Energy Research Center (a research center in Electric Power College, South China University of Technology) in distributed RE power system. The paper is mainly divided into three parts, including wind energy generation, photovoltaic generation and energy management system. Firstly, the wind energy generation control technologies is presented in variable speed constant frequency, maximum wind power capture, power decoupled control, pitch control, low voltage ride through, and grid synchronization. Secondly, the photovoltaic generation control technologies is introduced including photovoltaic maximum power point tracing, configuration and optimization of photovoltaic array and grid-connected converter. Lastly, the energy management system is proposed as the super manage layer to hybrid REs, which including wind speed forecast, integrative evaluate to power quality, power quality analytical instrument and the construction of energy management system based on multi-agent technology.

Prediction of wind power generation based on time series wavelet transform for large Wind Farm

Abstract: The development of wind generation has rapidly progressed over the last decade, the most important application for wind power prediction is to reduce the need for balancing energy and reserve power, which are needed to integrate wind power into the balancing of supply and demand in the electricity supply system. This paper presents a new method of wind power prediction in short-term with Artificial Neural Network (ANN) prediction model based on wavelet transform of chaotic time series. The data from the wind farm located in the Fujin Wind Farm of China are used for this study. The results reported in this paper show that the new method based on wavelet neural networks has better prediction properties than its similar back-propagation networks for prediction of wind power generation.

Position control of induction motor using indirect adaptive fuzzy sliding mode control

Abstract: This paper presents the design of an indirect adaptive fuzzy sliding mode controller for a vector controlled induction motor position servo drive. The proposed adaptive controller takes advantage of sliding mode control (SMC) and proportional integral (PI) control. The chattering effect is attenuated and robust performance can be ensured. Moreover, the upper bound of the discontinuous control term is assumed to be unknown and adaptive algorithm is applied to estimate it. The stability analysis for the adaptive control scheme is provided. Simulation example is presented to verify the effectiveness of the proposed method.

Research on control strategy for Three-Phase PWM Voltage Source Rectifier

Abstract: This paper first introduces the topology of Three-Phase PWM Voltage Source Rectifier (VSR). Then the mathematical models in three-phase static and two-phase rotary coordinate system are built. Based on that theory and the voltage-oriented vector control's idea, the paper introduces a dual-channel closed-loop control strategy with current-inner-loop and voltage-outer-loop. Active power channel is aim to make DC side voltage remain steady, and reactive power channel can regulate power factor by set current q-axis component reference. In order to prove that voltage-outer-loop is necessary, the paper builds a comparative model without a voltage loop. According to change current q-axis component reference value, illuminate reactive power channel's effect. In MATLAB/SIMULINK, the paper sets up simulation models for above cases. The simulation results show that the voltage-outer-loop is essential, and prove that current q-axis component can regulate power factor. The Three-Phase PWM Voltage Source Rectifier dual-channel double-closed-loop control strategy is effect.

The research on application of variable universe fuzzy control to maximum power point tracking system

Abstract: Solar energy is considered to be the world's most promising new energy technologies. How to find the best control strategy to maximize the advantages of photovoltaic system will greatly promote the development of photovoltaic technology. The variable universe fuzzy control is applied to the maximum power point tracking (MPPT) control in this paper. The variable universe fuzzy control is different from the conventional fuzzy control. It has a superior feature over the latter. In order to increase the precision of control, we must significantly increase the number of fuzzy partition, thereby increasing the conventional fuzzy control rule that have a greater impact on the output of fuzzy controller. However, an increase in the number of fuzzy subset will increase the difficulty of the controller design. While variable universe fuzzy control can make use of the domain of contraction so as to achieve the same control as to increase the fuzzy subset. The error and error rate of change are selected as a variable universe fuzzy control of the two input variables and the duty cycle for the output variable. The photovoltaic power output error and error rate of change are detected in real-time, and then the two variables are entered to regulate their own input domain, and the contraction factor of the input domain and output domain are calculated. It can control the duty cycle superiorly. After the test of simulation, the variable universe fuzzy control can achieve higher level control precision, better speed tracking performance. The variable universe fuzzy control is proved one of the best control strategies.

Novel Cuk circuit and Its application in photovoltaic system

Abstract: This paper designs a isolated resonance Cuk circuit based on the theoretical analysis of Cuk circuit, and do experiment of this circuit, also research the circuit's working principle and transmission efficiency under different load; Combining with the PV arrays working characteristics, this circuit was applied in photovoltaic(PV) generating control system to realize the maximum power point tracking of PV arrays and reduce the electromagnetic interference to external environment. The experimental results show that this novel isolated Cuk circuit has higher transmission efficiency, and can realize the control of the PV cells better.

Analysis and comparison of three implementation methodologies for high-resolution DPWM

Abstract: Digital pulse-width modulator (DPWM) is a crucial module for digitally controlled switching mode power supply (SMPS). High-resolution DPWM must be implemented under a reasonable clock frequency in order to satisfy the precision of output voltage and avoid limit cycles. Three methodologies which are the Delay-Line method, the Delta-Sigma (Δ-Σ) method and the Hybrid method are respectively used to realize an 11-bit resolution DPWM on FPGA with a 32MHz hardware clock frequency in this paper. This paper introduces the basic principle of the three methodologies and analyzes the advantage and disadvantage of them. Finally, it gives the experimental results of a digitally controlled SMPS system consisting of a synchronous buck converter and above DPWM, and compares the effects of the three methodologies on steady-state and dynamic performance.

Power dispatching of distributed wind-Solar power generation hybrid system based on genetic algorithm

Abstract: This paper aims at seeking reasonable power dispatching scheme for distributed wind-Solar power generation hybrid system, to satisfy some basic requirements, such as dispersed electric power demand, electric power quality and reducing generation cost and so on. Firstly we represented some elements of the main parts in the hybrid system; and then made basic dispatching strategies according to different situations; then pointed out four improving measures to improve basic genetic algorithm, such as, (1). Modify the producing way of selection probability, (2). Improve the way of crossover, (3). Protect excellent chromosomes, (4). Change mutation range and so on. In the end, we try to solve the units commitment for dispatching plan problem based on the improved genetic algorithm, and the application seem proved it reasonable.

Research on energy management for Wind/PV Hybrid power system

Abstract: In this paper, we discuss the universal issues about energy management for wind/pv hybrid power system in order to improve energy efficiency. On this basis, we developed a digital controller of street lamp lighting system based on the AVR MCU. It adopts a Duble-BUCK circuit to realize the coordination control between wind and solar energy. On the other hand, it can also track the maximal power point of solar battery and optimize the charge curve of Lead-acid battery. Experiments suggest that it can realize energy management and control effectively for Wind/PV Hybrid power system.

Design and analysis of a dSPACE-based position control system for a linear switched reluctance motor

Abstract: This paper presents a high-precision position control system for a linear switched reluctance motor (LSRM) based on dSPACE real-time control platform. The LSRM has a very simple structure and it can be manufactured easily, and there is no need for magnets. The control system utilizes dSPACE development platform as the controller and generates the real-time code for the control algorithm and motor model, tuning the control parameters online and PD algorithm is implemented. The experiment results indicate that with the control method presented in the paper, the position error is less than 0.04 mm. Also compared with traditional research and development method, using dSPACE real-time control platform is able to quickly complete research and development for this kind of position control system, and the advantages are not only to shorten the entire system development cycle but also ensure system reliability and reduce costs.

Simulation of the integrated controller of the anti-lock braking system

Abstract: This paper presents simulation of integrated controller of vehicle anti-lock braking system, which consists of the traditional continuous PID and finite state machine theory. Based on the integrated controller, slip ratio and deceleration are selected as the main control parameters to optimize ABS. Vehicle speed, wheel speed, braking distance, pressure state and slip ratio are investigate to reveal the performance of anti-lock braking system. Single-wheel system is studied in this paper to prove that the controller can effectively reduce braking distance and time and also can improve the stability of anti-lock braking system, which can provide a guideline to the design of anti-lock braking system.