Electric Traction Motor Research Articles

Hybrid electric system based on fuel cell and battery and integrating a single dc/dc converter for a tramway

This paper presents a hybrid electric power system for a real surface tramway. The hybrid system consists of two electrical energy sources integrating a single dc/dc converter to provide the power demanded by the tramway loads (four electric traction motors and auxiliary services): (1) a Polymer Electrolyte Membrane (PEM) fuel cell (FC) as the primary and (2) a rechargeable Ni–MH battery as electrical energy storage to supplement the FC over the driving cycle. According to the requirements of the real driving cycle of the tramway, it was considered a 200 kW PEM FC system with two FCs connected in parallel and a 34 Ah Ni–MH battery. The PEM FC and Ni–MH battery models were designed from commercially available components. The power conditioning system provides the appropriate power for the tramway. It is composed of: (1) a unique dc/dc boot converter which adapts the FC output voltage to the 750 V traction standard dc bus; (2) three phase inverters to drive properly each electric motors; and (3) a braking chopper to dissipate excess of regenerative braking energy. Suitable state machine control architecture is presented for the hybrid system, its objective being to provide demanded power by the driving cycle, optimizing the energy generated. Following this objective, a new state machine control strategy based on eight states decides the operating point of each component of the system and a cascade control structure allows achieving the operating points determined by the strategy. Simulation results of the real driving cycle of the tramway check the adequacy of the hybrid electric power system.

Rational control laws asynchronous electric traction

The paper considers the optimal control laws for asynchronous traction electric motors to minimize various types of losses, minimize consumption of active and reactive power, maximum overload capacity. The authors established that the joint management of the maximum torque and minimum total losses in the motor is most efficient traction control law for asynchronous traction electric motors.

Capacitors vs. Batteries in a Serial Hybrid Electric Bus

Serial hybrid electric vehicles are propelled by electric traction motors, where electric power is delivered by an engine-generator set and an energy storage system. This paper compares the use of electric double layer capacitors (EDLCs) to that of NiMH-batteries in a 24 m long bi-articulated serial hybrid electric bus for public transportation in terms of fuel economy of the two systems. In order to analyze the influence of buffer size, the buffer-power ratio (ratio of maximum power of buffer and generator) is varied, while the overall power-to-weight ratio of the vehicle is held constant. As a reference, a diesel engine powered bus is simulated on the same driving mission. The vehicle designs are compared based on their optimal fuel economy, which is evaluated using dynamic programming. The results show that EDLCs outperform batteries for buffer-power ratios above 40%. This indicates that for the serial configuration, high buffer efficiency and specific power are more important than high energy density. In order to achieve better fuel economy than conventional, the hybrid is required to have a minimum buffer-power ratio, which is about 20% for urban driving, and 30% for mixed driving. The maximum fuel saving potential compared to conventional is about 16% for urban, and 8% for mixed driving.

Improvement of drivability and fuel economy with a hybrid antiskid braking system in hybrid electric vehicles

When braking on wet roads, Antilock Braking System (ABS) control can be triggered because the available brake torque is not sufficient. When the ABS system is active, for a hybrid electric vehicle, the regenerative brake is switched off to safeguard the normal ABS function. When the ABS control is terminated, it would be favorable to reactivate the regenerative brake. However, recurring cycles from ABS to motor regenerative braking could occur. This condition is felt to be unpleasant by the driver and has adverse effects on driving stability. In this paper, a novel hybrid antiskid braking system using fuzzy logic is proposed for a hybrid electric vehicle that has a regenerative braking system operatively connected to an electric traction motor and a separate hydraulic braking system. This control strategy and the method for coordination between regenerative and hydraulic braking are developed. The motor regenerative braking controller is designed. Control of regenerative and hydraulic braking force distribution is investigated. The simulation and experimental results show that vehicle braking performance and fuel economy can be improved and the proposed control strategy and method are effective and robust.

THE DETERMINATION OF THE EQUIVALENT CURRENT LOAD WHILE TESTING THE TRACTION MOTORS ON THE HEAT WITHOUT VENTILATION

The theoretical determination procedure of an equivalent loading current in tests of traction electric motors on heating without ventilation is offered. The results of calculation of an equivalent current for traction engine ED-118A are presented, as well as the method accuracy is experimentally confirmed.

UNIFICATION OF BOOSTERS DEVICES STANDS FOR TESTING OF TRACTION MOTORS OF ELECTRIC LOCOMOTIVES DC

The methods of determination of the optimal parametric series of boosters for the test desks for traction electric motors of direct current electric locomotives are offered in the article.

Determining parameters of equivalent circuit of frame insulation in traction motors

The determination of a set of parameters that characterize a mathematical insulation model and its equivalent circuit according to the processes that take place in insulation, particularly according to the self-discharge voltage, is considered. A three-layered equivalent circuit is shown to be most suitable for analyzing processes that take place in the frame insulation of traction electric motors.

Ways to calculate electric fields in traction electric motor insulation by equivalent charge method

A procedure permitting one to calculate the electric fields in multilayer insulation based on the equivalent charge method is presented. Consideration of the new algorithm shows its fast response and proper accuracy.

Automatic Control of Hybrid Transmission of an All-Wheel Drive Vehicle

The present article describes the bases of automatic control by an internal combustion engine and reversible hybrid drive under work in mode of traction electric motor and generator of the all-wheel drive, multi-purpose car with parallel hybrid drive on an example of a UAZ 3153 car equipped with hybrid power instalation.

Modeling of overheat process control of electric motor

Modeling of overheat process control of electric motorThe paper presents the research of heating electric traction motor, the temperature dependence of the load current and control impact. The process of heat in heating electric traction motor is given.

Comprehensive Efficiency Modeling of Electric Traction Motor Drives for Hybrid Electric Vehicle Propulsion Applications

Extensive research done in the recent past has proven that power electronic converters and electric propulsion motors are extremely critical components for modern hybrid electric vehicle (HEV) propulsion applications. Therefore, it is essential that both the traction motor and the associated drive operate at their optimal efficiencies throughout the driving schedule. In typical HEV propulsion applications, the traction motor and the drive are used over the entire torque/speed operational range. In view of this fact, this paper aims at modeling the inverter and motor losses/efficiencies over typical city and highway driving schedules. The noteworthy losses within a typical three-phase dc/ac traction inverter, such as the switching and conduction losses for both the insulated-gate bipolar transistors and the antiparallel diodes, are modeled and simulated over the city and highway driving patterns. An induction motor (IM) is used for a medium-sized sport utility vehicle, which was modeled in the advanced vehicle simulator (ADVISOR) software. The significant IM losses that were considered in the study include the stator copper losses, rotor copper losses, and core losses. Thus, the average efficiencies of both the inverter drive and the induction traction motor are evaluated and summarized under city as well as highway driving conditions. Finally, based on the individual-model-based efficiency analysis, the overall traction motor drive system efficiency is estimated.

IGBT Device Application Aspects for 50-kW Zero-Current-Transition Inverters

The operational conditions and behaviors of semiconductor devices in soft-switching inverters are quite different from those in conventional hard-switching inverters; this has significant impact on the design optimization. This paper addresses two application aspects of insulated gate bipolar transistor (IGBT) devices for two different types of three-phase zero-current-transition (ZCT) soft-switching inverters, which are built with 50-kW power rating for electric vehicles traction motor drives. One aspect is the characterization of main IGBTs under different ZCT conditions, for which switching loss reductions are quantified, and variations of soft-switching behaviors and mechanisms under different resonant tank designs are investigated and compared. The other is the selection and characterization of auxiliary switches. From the analysis on the unique nonconventional operation conditions of the auxiliary switches, it is concluded that the current ratings specified for commercial IGBTs cannot meet the requirements for the auxiliary switches. Accordingly, methods to select and characterize suitable auxiliary switches are proposed, and IGBTs from different manufacturers are tested and compared using the proposed methods. Hardware implementation and experimental results of the 50-kW prototypes are provided.

Hybrid electric vehicles: year 2000 status

In the year 2000, the automotive manufacturers turned their attention to Hybrid Electric Vehicles (HEV). This re-direction of Electric Vehicle (EV) development effort was highlighted at the North American International Auto Show (NAIAS 2000), where, the World's major automobile manufacturers displayed twenty three HEVs. Thirteen HEV were configured with an internal combustion piston engine and electric traction motor, while, ten additional HEV were configured as fuel cell and battery pack hybrid vehicles (FCHV). Furthermore, the FCHV were fueled with hydrogen (H/sub 2/) from H/sub 2/ absorption metal hydride fuel tanks, or, from liquified hydrogen cryogenic fuel tanks. One conclusion for HEV was that the preferred configuration includes a compression ignition engine paired with an electric motor, and, four speed manual transmission with automatic shift. A second conclusion for FCHV was that the fuel of choice is H/sub 2/, and furthermore, these H/sub 2/ fueled FCHV were the precursor vehicles foreshadowing deployment of a hydrogen fuel infrastructure within the first quarter of the 21/sup st/ Century.

95/03673 Investigation of the commutator quality of electric traction motors by means of the transformation method

95/03673 Investigation of the commutator quality of electric traction motors by means of the transformation method

Investigation of the commutator quality of electric traction motors by means of the transformation method

The reliability of contemporary traction motors and the factors which have an effect on them are studied in this paper. The centre of interest of the article is the description of the transformation method of determining the quality of a commutator, the substance of which consists in picking up the current between brushes of the same polarity with the simultaneous gradual rotation of the armature through 360° while feeding the main poles with alternating voltage.

Electric railway traction. Part 1: Electric traction and DC traction motor drives

This series of tutorial articles explains the electrical and control engineering background in electric railways. The articles cover traction drives with DC and AC traction motors, electrification systems, and railway signalling and control systems. This first article covers the nature of the traction load, the requirements of the traction duty cycle and power electronic controlled traction drives using DC machines.

Integrated microprocessor control of a hybrid i.c. engine/battery-electric automotive power train

This paper describes the development of a fully integrated microprocessor control system for a hybrid i. c. -enginelbattery-electric automotive power train. Torque control systems for the internal-combustion engine and the electric-traction motor are designed using digital transfer functions and indirect methods of torque measurement. Root-locus methods are used in all designs to provide fast, critically damped closed-loop response. In all cases simple proportional-plus-integral control proved sufficient to achieve this. An overall cycle speed controller allows the laboratory test system to be exercised over any test driving cycle and offers the ability to carry out sophisticated power sharing and transmission shifting strategies.

Identification and performance simulation of a hybrid i.c.-engine/battery electric automotive power train. Part 2: The electric traction system

This paper, and its companion, describe the identification, modelling and simulation of the drive-train components in a hybrid i.c.-enginelbattery electric car. This paper concentrates on the electric traction system and describes the identification of discrete transfer functions that relate motor current and motor shaft torque to the input demand to the power electronic controller. All the traction system transfer functions identified are related to a theoretical unalysis of the DC traction system and both full- and reduced-order models are derived. In the identification procedure the non-linear gains are identified separately to the system dynamics which leads to system transfer functions that are ideally suited for controller design. It is shown thut the power electronic controller has three distinct operating modes, and transfer functions are identified for each mode. Simulated results are compared with test data and the identified transfer functions shown to describe the behaviour of the electric traction system accurately. A method to predict motor torque by measuring armature current and field current is also presented. With the identified system transfer functions it is possible to design a control unit which will control the torque from the electric traction motor in a smooth manner.

Identification and performance simulation of a hybrid i.c.-engine/battery electric automotive power train. Part 1: The i.c. engine

This paper, and its companion Part II, describes the modelling and simulation of the drivetrain components in a hybrid i. c. -enginelbattery electric car. In this part particular attention is paid to describing the hybrid drive system and the identification procedure used to obtain discrete z-transfer functions of the system components. A full physical analysis of the i.c. engine is described and used, along with the identification procedure, to identify discrete transfer functions relating engine torque and speed to accelerator demand. A comparison of experimental and simulated data confirms the validity of the identified transfer functions. With these transfer functions, and those produced in the companion paper for the electric traction system, it is possible to design a main hybrid vehicle control unit which can both schedule, and control, the torque from either, or both, the i. c. engine and the electric traction motor in a smooth manner.

DYNAMIC PROCESSES IN THE DRIVE SYSTEM OF ELECTRIC TRACTION VEHICLES

SUMMARY The drive system of electric railway traction vehicles is basically influenced by two main exciting effects. On the one hand, the exciting effect of electric traction motors may be of considerable importance, whilst on the other hand, the vertical and pitching vibrations of the vehicle due to the always present track uneven-nesses are transferred to the wheel-rail tangential force, and, in turn, they give rise to excited dynamic processes. In this study, the complex dynamic analysis of the drive system of a 25 kV, 50 Hz electric traction unit with two identically built power-bogies is dealt with.