Modelling of an integrated grid-connected three-phase current source unidirectional buck battery charger for electric traction application

Modelling of an integrated grid-connected three-phase current source unidirectional buck battery charger for electric traction application

Environmental pollution is one of the serious issues in the current era. In diminishing this issue, electric vehicles (EVs) can play one key role. Again, along with the development of modern drive technologies in various electric traction applications, a comprehensive understanding of proper motor selection, is also becoming much important. This paper compares induction motor (IM), brushless DC (BLDC) motor and permanent magnet synchronous motor (PMSM) for EV traction applications. In this study, field-oriented control (FOC) strategy with ANN based controller, is chosen due to its accuracy, fast dynamical response and ease of proper torque and speed control. This comparative study and the model simulation has been carried out in the MATLAB/Simulink environment.

A novel control method based on the proportional resonant differential (PRD) control is proposed for the grid-connected current source inverter (CSI) used in the direct drive permanent magnet synchronous wind generation system. By the optimal design of the parameters of the PRD controller in two-phase stationary frame, the CSI system can realize zero steady-state error control and effectively damp the resonance caused by its output LC filter just by feeding back the grid-connected current. This not only greatly simplifies the controller design but also enhances the stability of the system. Simulation results show grid-connected CSI with this method has fast dynamic response and good steady-state performances.

Drive circuitry of an electric vehicle enabling rapid heating of the battery pack at low temperatures.

Maximum power point tracking (MPPT) controllers are a key element in photovoltaic (PV) energy conversion systems since they allow extracting the maximum power from PV generators. Metaheuristic algorithms such as the particle swarm optimization (PSO) are nowadays widely adopted and have shown their superiority to many other techniques. In this paper, a PSO-based MPPT algorithm is implemented to extract the maximum power from a grid connected current source inverter (CSI)-based PV system. CSIs are, inherently, single-stage boost-type topologies, which allow the injection of high quality sinusoidal AC currents with controllable power factor into the grid with a DC-link voltage level lower than the grid voltage amplitude. Accordingly, a space vector with pulse width modulation (SVPWM) technique is developed to, properly, control the CSI’s power switches and an appropriate proportional integral (PI) DC-link current controller is designed to ensure that the real power injected into the grid is always equal to the maximum power that can be extracted from the PV panel under all conditions. A numerical co-simulation of the overall PV system is realized using Matlab/Simulink and PLECS environments and the obtained results show the effectiveness of the proposed techniques for grid-connected PV applications.

Traditionally DC-AC converters are considered with voltage source inverters (VSI); although less studied and discussed, it has started recently to be used current source inverters (CSI). Another possibility for DC/AC conversion is the multilevel configuration. This paper shows experimental operation and simulation analysis of a grid-connected multilevel current source inverter (MCSI), which includes a circuit for equipment safety reasons due to grid disconnections.

In this paper, a hybrid excitation synchronous machine (HESM) with magnetic shunting rotor is designed for electric vehicle traction applications with consideration of electromagnetic performance and mechanical strength. The HESM with magnetic shunting rotor is a topology of brushless HESM with extended magnetic bridge to embed field windings. The rotor core extends along the axial direction and the increase of rotor length is inevitable, which reduces torque density. In order to improve torque density, the excitation structure is optimized by built-in field windings and the HESM with one-end built-in field windings is presented. To improve the flux regulation capability and decrease the magnet consumption further, the HESM with dual-end built-in field windings is proposed and investigated. The comparative study of the performances of the original HESM and the HESMs with one/dual-end built-in field windings is carried out by three-dimensional finite element method (FEM). An original HESM prototype and a permanent magnet synchronous machine prototype have been developed and the experimental results, which agree well with the FE-predicted results, confirm the advantages of HESM and the validity of FEM used in predictions in this paper.

The eddy current loss in the magnets of permanent magnet (PM) motors in a hybrid electric vehicle (HEV) and plugin HEV is usually not taken into consideration in traditional motor design and analysis. However, due to the high conductivity of the rare-earth magnet, neodymium-iron-boron (NdFeB), and slot/tooth harmonics, there is eddy current loss generated inside the magnets. This loss may not attribute very much to the efficiency of the motor, but the temperature-rise inside the magnets caused by this loss can lead to the unpredictable deterioration of the magnets. In addition, the output voltage of pulse-width-modulated (PWM) inverter contains abundant high frequency harmonics, which induce additional loss in the magnets. This paper presents the modeling and analysis of eddy current loss in surface-mounted-magnets of PM motors operated by PWM inverters for HEV/PHEV and electric vehicle traction applications. In order to evaluate the loss from pure sinusoidal and PWM inverter supply, an analytical method is implemented, in conjunction with time-stepped finite-element analysis (FEA). The simulation results validated the proposed model.

In this paper, a new flux-concentrating rotor with interior permanent magnet (IPM) of double stator and single rotor (DSSR) axial flux permanent magnet (AFPM) motor is proposed for electric vehicle traction application. Compared with the traditional surface-mounted PM rotor and spoke-type IPM rotor, the saliency effect of the proposed IPM rotor can be significantly increased to improve torque performance, as well as reduce rotor losses and increase efficiency. First, the topological structure flux-concentrating principle of the rotor with inserted PMs are introduced and analyzed. The direct-axis or quadrature-axis magnetic path are dissected in depth to explain the contribution rate of reluctance torque. Then, the design and optimization of AFPM motors with traditional surface-mounted rotor, spoke-type IPM rotor and the proposed rotor are carried out to pursue torque density. Finally, the electromagnetic performances of three AFPM motors are compared by finite element analysis (FEA). The results of comparative analysis show that the proposed rotor has some obvious advantages including motor overload capacity, power/torque density and maximum efficiency.

The issues of improving the multifunctional converter with the combination of the function of the active filter for a photoelectric power system with a storage battery for a local object with a connection to the grid are considered. The principles of autonomous operation mode implementation with the use of the current value of the short-circuit current of the photovoltaic battery and the regulation of load power are developed. The control system of the unit with alterable structure of regulators is improved. It contains: internal current control loop of grid inverter, external voltage stabilization loop at the inverter input at work with grid and circuit with regulator of load voltage in autonomous mode. Depending on the power of the photovoltaic battery and the load, the maximum and actual value of the current of the photovoltaic battery, the degree of charge of the storage battery, limiting the current of the grid, the voltage stabilization is provided by regulating the current of the grid or current of a photovoltaic battery or current of a storage battery. This is carried out by one of the three voltage regulators, determined by the control unit. In autonomous operation mode, to maintain the possibility of recharging the storage battery, simultaneous operation of the channels for regulating the current of the photovoltaic battery and the storage battery current is possible while reducing the load voltage within acceptable limits; the maximum power mode of the photovoltaic battery is set according to the measured value of the short-circuit current of it. There is a mode of compelled storage battery charge for multi-zone tariffing. The results of simulation of the system “grid - converter - load” confirm the efficiency of the proposed solutions.

Renewable or Sustainable Energy (SE) sources such as photovoltaic (PV) cells usually generate variable power. Hence power electronic circuits are used to extract maximum power from these sources at all times. Further, Grid-integration demands tight technical standards to be met. Hence novel power electronic converter topologies are used to bring down the level of harmonics while interfacing the SE sources with the utility of fixed grid voltage. These two functions can be performed using two separate power conversion stages. But this would reduce the overall efficiency and reliability of the system. Hence, it is desirable to use a single power electronic conversion stage to perform both the functions. This paper evaluates a single stage power electronic converter topology capable of boosting the variable dc voltage towards the ac mains. The chosen topology, a Current Source Inverter (CSI), is used as an interface between the PV source and the utility. The paper discusses the principle of operation, control and protection strategy used for this topology. Experimental results of the Grid-Connected (GC) Current Source Inverter (CSI) based PV system using real time Digital Signal Processor dSPACE are also presented. Finally three phase sinusoidal currents are injected into the grid at unity power factor (UPF).

The design of Synchronous Reluctance Motor (SynRM) has a lot of variables. There are some difficulties to design proper rotor-flux barrier geometry. It is necessary obtain an optimized geometry to get the satisfactory results of torque ripple, average torque, etc. SynRM is a new motor topology but in electrical railway applications is not working yet. The mature topology in this application is Induction Motor (IM). The main contribution of this paper is to compare both motors and obtain an answer about if we can use SynRM in electrical railway applications replacing IM and whose are advantages and disadvantages of this topology in the application. To compare both topologies we select a traction IM and its performances to design a SynRM that get the same ones. The comparison has been carried out on finite-elements analysis (electromagnetic and thermal analysis) of SynRM.

Due to the high-power density and compact structure, axial-flux permanent magnet (AFPM) machines have gradually received much attention with a view to researching breakthroughs in the next generation electric drive technology for electric vehicles in the recent decades. The AFPM machines with factional slot concentrated winding (FSCW) and yokeless stator, namely yokeless, and segmented armature (YASA) motors, have drawn much attention for its high-power density and potential manufacturability due to the concentrated winding and modular stator core configuration. However, the significant rotor loss resulting from the abundant armature reaction harmonics in FSCW machines imposes a great challenge to the rotor heat dissipation, especially when the pursuit of higher speed has become the trend for electric vehicle applications. On the other hand, distributed winding is widely used in high speed radial flux permanent magnet (PM) machines due to its low armature reaction harmonics. In order to figure out the advantages and disadvantages of various winding arrangement and rotor configuration of AFPM for electric vehicle applications, the comparative study of four AFPM machines with various winding configurations and rotor PM arrangements are comprehensively conducted in this article. First, the design and primary optimization of the four AFPM machines are conducted for the electric vehicle requirement specifications. Then, a comprehensive three-dimensional finite-element analysis (FEA) is employed to compare the electromagnetic performance including torque/power density, efficiency, and flux-weakening capacity. Furthermore, the guideline of winding selection of AFPM machines for electrical vehicle is given. Finally, a yokeless stator AFPM prototype with ISDW configuration is manufactured and tested to verify the validity of the FEA results, as well as confirm the comparison conclusion.

In electric traction application electrical energy used was: 1.direct current and 2.alternating current. In this world already a constant voltage constant frequency single phase and three phase AC readily available. For some applications it is needed to have variable voltage and variable frequency for this conversions need between dc and ac sources, and this conversion can be carried out by power converters. For converting AC-AC cycloconverter are widely used as a converter. The n s of alternating current drives relates with the frequency (f) and number of poles (p) present in the induction motor. It is not feasible by changing the poles of a motor under running processes, so the only one way during running condition the frequency can be varied. In the absence of direct current (DC) link with constant voltage constant frequency alternating current to variable voltage variable frequency alternating current is needed to run the electric traction applications, so the cycloconverter will make this as possible with reliable and economical. This work explains how to control the speed of single phase induction motor and single phase to single phase Cycloconverter using different frequency conversions with R Load was carried out using MATLAB / Simulink.

The paper deals with the following three topics: main drives, supply systems, and auxiliaries on vehicles. After a short review of the evolution typical examples, which represent the actual state of the art, are used to illustrate design and mode of operation of the power electronic systems. In addition it is indicated, in which direction power electronics in electric traction applications could develop in the future. Since the reliability of trains depends strongly on their low power electronic equipment, it is shown, how its mean time between failures has to be improved despite the hostile ambient conditions on a railway vehicle. >