With the requirements for reducing emissions and improving fuel economy, automotive companies are developing electric, hybrid electric, and plug-in hybrid electric vehicles. Power electronics is an enabling technology for the development of these environmentally friendlier vehicles and implementing the advanced electrical architectures to meet the demands for increased electric loads. In this paper, a brief review of the current trends and future vehicle strategies and the function of power electronic subsystems are described. The requirements of power electronic components and electric motor drives for the successful development of these vehicles are also presented.

Power Electronics and Motor Drives in Electric, Hybrid Electric, and Plug-In Hybrid Electric Vehicles

This paper presents a review of recently used direct torque and flux control (DTC) techniques for voltage inverter-fed induction and permanent-magnet synchronous motors. A variety of techniques, different in concept, are described as follows: switching-table-based hysteresis DTC, direct self control, constant-switching-frequency DTC with space-vector modulation (DTC-SVM). Also, trends in the DTC-SVM techniques based on neuro-fuzzy logic controllers are presented. Some oscillograms that illustrate properties of the presented techniques are shown.

Direct torque control of PWM inverter-fed AC motors - a survey

Field-oriented control and direct torque control are becoming the industrial standards for induction motors torque control. This paper is aimed at giving a contribution for a detailed comparison between the two control techniques, emphasizing advantages and disadvantages. The performance of the two control schemes is evaluated in terms of torque and current ripple, and transient response to step variations of the torque command. The analysis has been carried out on the basis of the results obtained by numerical simulations, where secondary effects introduced by hardware implementation are not present.

FOC and DTC: two viable schemes for induction motors torque control

This paper presents a new direct power control (DPC) strategy for a doubly fed induction generator (DFIG)-based wind energy generation system. The strategy is based on the direct control of stator active and reactive power by selecting appropriate voltage vectors on the rotor side. It is found that the initial rotor flux has no impact on the changes of the stator active and reactive power. The proposed method only utilizes the estimated stator flux so as to remove the difficulties associated with rotor flux estimation. The principles of this method are described in detail in this paper. The only machine parameter required by the proposed DPC method is the stator resistance whose impact on the system performance is found to be negligible. Simulation results on a 2 MW DFIG system are provided to demonstrate the effectiveness and robustness of the proposed control strategy during variations of active and reactive power, rotor speed, machine parameters, and converter dc link voltage

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Direct active and reactive power control of DFIG for wind energy generation

Medium-voltage (MV) induction motors are widely used in the industry and are essential to industrial processes. The breakdown of these MV motors not only leads to high repair expenses but also causes extraordinary financial losses due to unexpected downtime. To provide reliable condition monitoring and protection for MV motors, this paper presents a comprehensive survey of the existing condition monitoring and protection methods in the following five areas: thermal protection and temperature estimation, stator insulation monitoring and fault detection, bearing fault detection, broken rotor bar/end-ring detection, and air gap eccentricity detection. For each category, the related features of MV motors are discussed; the effectiveness of the existing methods are discussed in terms of their robustness, accuracy, and implementation complexity. Recommendations for the future research in these areas are also presented.

A Survey of Condition Monitoring and Protection Methods for Medium-Voltage Induction Motors

The universal field oriented (UFO) controller operating in the air gap flux reference frame is applied to a current regulated PWM induction motor drive. The air gap flux is measured by the stator third harmonic voltage component. It is shown in the paper that due to motor saturation, a third harmonic flux component is generated in the air gap. Since the third harmonic flux component is a function of the fundamental air gap flux and is always in phase with it for any load condition, it constitutes an accurate way to measure the fundamental air gap flux. This harmonic flux component induces a third harmonic in each one of the motor phase voltages, and the paper shows how this voltage is processed for the measurement of the air gap flux and consequent implementation of the UFO controller. Due to the robustness of the third harmonic sensing method and to the structure of the UFO controller, the resulting drive is not affected by detuning errors in steady state operation. In addition, the UFO drive has excellent dynamic performance even under strongly detuned conditions. To avoid any transition between the indirect universal field orientation (IUFO) (suitable controller structure for low speed) and the direct universal field orientation (DUFO) (suitable controller structure for high speed), a new type of UFO, i.e. a combination of the two methods is presented. >

Universal field oriented controller based on air gap flux sensing via third harmonic stator voltage

Due to the increase of electromagnetic and electromechanical devices supplied by static converters, the classification and evaluation of the energetic behavior of soft magnetic materials, with nonsinusoidal supply, is becoming mandatory. In this paper, the possibility of defining a standard methodology for the specific iron loss measurement (iron losses per mass unity), with static supply, is analyzed. In particular, the paper underlines the main problems which can be found when standard magnetic measurements are carried out with nonsinusoidal sources. Pulsewidth modulation (PWM) inverters can be considered an industrial standard solution as a static supply source. As a consequence, the problems linked to the use of this kind of supply with magnetic material have been analyzed, taking into account the effects due to the PWM inverter characteristics (for example, modulation index, switching frequency, and modulation technique). In addition, in the paper, a basic structure of a standard test bench is proposed, also taking into consideration the required instrumentation.

About the possibility of defining a standard method for iron loss measurement in soft magnetic materials with inverter supply

Energy Consumption of ProTaper Next X1 after Glide Path with PathFiles and ProGlider

In this paper the thermal behavior of two induction motors (2.2 and 4 kW, 4 pole) and two synchronous reluctance motors (transverse laminated) are investigated and compared. Both motor types use the same stator, but have different rotors. Using a lumped parameter simulation program, a thermal analysis has been also carried out and the obtained results have been compared to the experimental ones. A direct comparison of the thermal behavior of the two motor types has been thus made, for constant load and constant average copper temperature conditions. Since the synchronous reluctance motor has negligible rotor losses compared to the induction motor, it is capable of a larger rated torque, from 10% to more than 20%, depending on the relative size of end connections and motor length

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Thermal analysis of induction and synchronous reluctance motors

The extraction of energy from ocean waves has been investigated in Europe since the 1970s. Hundreds of devices have been proposed, many have been tested in some form or other and a few of these have been commercialized. In this paper a gyroscopic wave energy converter is studied and a procedure to design a prototype model to be tested at the wave tank at the University of Edinburgh is outlined. A linearized model of the device is extrapolated and used as a mathematical tool in the design process. The final version of the prototype model is verified using the complete nonlinear model.

Michele Pastorelli

Papers

Universal field oriented controller based on air gap flux sensing via third harmonic stator voltage

About the possibility of defining a standard method for iron loss measurement in soft magnetic materials with inverter supply

Energy Consumption of ProTaper Next X1 after Glide Path with PathFiles and ProGlider

Thermal analysis of induction and synchronous reluctance motors

ISWEC: Design of a prototype model with gyroscope