Search Results

The new wireless rotor electrical machine has all the coils placed on the stator. The laminated wireless rotor serves as a magnetic field switcher. A wireless rotor is cold, and it facilitates machine cooling. The model of the wireless rotor machine includes electrical and mechanical components. The wireless rotor machines can find an application in practice because they have advantages over existing devices. In modeling, we use a new approach. We consider a motor as a natural control system with torque feedback. Such an approach simplifies analyses and adjustment of the operation of an electrical machine. First, we analyze an open-loop control system without torque feedback. In this case, by changing the rotor speed under external torque, we can receive the torque-speed motor characteristics. After some adjustments to the open-loop system, we can consider the close loop control system with torque feedback. We use a space vector representation for sinusoidal electric components.

The development of the economy and the associated growth in trade both within the country and international transport, the associated construction and development of transport routes using elements of intelligent transport systems constantly require increasing the efficiency of trunk transportation. In addition, the development of new economic regions with an undeveloped road network is impossible without high-capacity motor vehicles and cross-country ability. To achieve these goals, the creation of active road trains, including multi-link ones, based on non-traditional technical solutions, is required. The idea of using multi-link trains in the system of intercity and international transportation is not new. However, at the present stage of development of automotive technology requires rethinking and use of new achievements of science and technology.

The article solves the problem of increasing the energy efficiency of the traction electric drive in the low load conditions. The set objective is achieved by analogy with internal combustion engines by decreasing the consumed energy using the amplitude control of the three-phase voltage of the induction machine. The basis of the amplitude control is laid by the constancy criterion of the overload capacity with respect to the electromagnetic torque, which provides a reliable reserve from a "breakdown" of the induction machine mode in a wide range of speeds and loads. The control system of the traction electric drive contains a reference model of electromechanical energy conversion represented by the generalized equations of the instantaneous balance of the active and reactive power and the mechanical load. The induction machine is controlled by two adaptive variables: the electromagnetic torque and the voltage amplitude.

Currently, in order to effectively use the engine's energy resources and implement the required indicators of the traction, speed and fuel-economic properties of a vehicle, designers and manufacturers are trying to realize some certain properties to the transmission design that will ensure the most complete coordination of their joint work. However, even the optimal constructive solution cannot be universal, i.e. what is good for some operating conditions is not effective for other conditions. Therefore, today it is economically expedient to create vehicles intended for a certain, relatively narrow range of operating conditions. A wide range of modern continuously variable transmissions (CVT), as well as automatic control systems make it possible to radically change the approach to the design of vehicle transmissions. It remains only to determine the algorithms for changing the gear ratio of the CVT.

Dynamics of acceleration, mobility, fuel efficiency of wheeled vehicles are largely determined by the drive circuit to the driving wheels and bridges, as well as devices used in drive link nodes to distribute power among the driving wheels. This is especially important for multi-axle wheeled vehicles. In this paper, the object of the study is a multiaxial wheeled vehicle with an electric transmission consisting of an internal combustion engine with a power of 720 kW, one common generator and twelve traction motors mounted directly on the driving wheels. In connection with the change in load on the driving wheels due to the variability of soil properties, driving conditions (acceleration, braking, uniform motion), terrain topography, it is necessary to provide external regulation of electric machines working in the transmission of the vehicle.

Regular induction motors operate at a constant value of voltage. They operate from zero external load to rated value. At low loads, motors works with reserve of the power. At low loads, motor can work with lower voltage, with lower current (lower power losses) and higher power factor (cos φ). In the paper, we consider theoretical basics of reduction of idle current and increase power factor in idle mode operation. We consider speed controller by changing value of motor voltage. With this controller, we can reduce idle current and increase its power factor. In addition, we consider current controller for limiting starting current by decreasing voltage during motor start, and reduction idle current with improved power factor in idle steady state conditions. Voltage change includes controlled (thyristor) rectifier or pulse width modulated converter of voltage. Controllers can include speed or current feedbacks. We consider digital model of induction motor with different controllers.

The problem of increasing the accuracy of determining the torque and the load angle of the permanent magnet synchronous motor of an electric traction drive to the predicted level (2.5...3)% of the full-scale error is solved by an indirect method. We considered the algorithms for calculating the generalized current and voltage of the electric motor, the total power, the instantaneous values of the power factor, and the sine of the phase angle between the first harmonics of voltages and currents. We determined the requirements for the accuracy of determining these values at the level of 1% of the full-scale error. We considered the algorithms for determining the total instantaneous power losses by the indirect method at the predicted level (15...20)% of the full-scale error with the efficiency of the motor (90...95)%.

With the development of the market of electric vehicles, the issue of efficient battery charging becomes even more urgent. Thanks to the continuous increase in the level of development of electronics, new opportunities appear to create power electrical equipment with previously unattainable characteristics. For these purposes, a universal algorithm for fast charging of LiFePO4 batteries been developed. It assumes the fastest charging of the battery without damage due to overheating or overcharging. The algorithm includes several main parts: the algorithm of initial temperature testing, the algorithm of initial trickle charging, the main current charging algorithm, the algorithm of permanent temperature testing, the main voltage charging algorithm, algorithm of permanent temperature testing, the algorithm for final trickle charging. The efficiency of the fast battery-charging algorithm studied by mathematical modeling. Computer modeling carried out using open source software.

The inertial continuously variable transmissions are transmissions of mechanical type. They have a number of advantages in comparison with other types of transmissions. For example, they have a big value of the coefficient of efficiency, since the principle of their action does not imply the need to convert energy from one type to another one. These transmissions have a compact design, a wide range of torque transformation. They can operate in direct mode, smoothing the torsional vibrations in the system. At the moment when the output shaft is stopped, the input transmission shaft continues to rotate, that prevents the engine from overloading. There are other advantages. But despite these advantages, the inertial transmissions are not widely used in the automotive industry. The main reason for this is the inadequate durability of the freewheel mechanisms involved in the designs of the inertial transmissions.

The inertial continuously variable transmissions are mechanical transmissions that are based on the principle of inertia. These transmissions have a lot of advantages. Usually, the design of the inertial continuously variable transmissions consists of inertia pulsed mechanism with unbalanced inertial elements and two overrunning clutches. Dynamics of the transmissions is described by systems of substantial nonlinear differential equations. In general, precise methods of solution for such equations do not exist. Therefore, in practice, approximate analytical and numerical methods must be employed. The main analytical methods employ successive approximation, a small parameter, or power series expansion. Each approach has its advantages and disadvantages. Therefore, we need to compare them in order to select the best method for dynamic study of such kind of transmissions.

The inertial continuously variable transmission is a mechanical transmission which is based on the principle of inertia. This transmission has a lot of advantages, namely: compactness, minimum friction losses and high efficiency as a result of the relatively small number of rotating components, a wide range of transformation of the torque. It does not need any conventional friction clutches. This transmission protects the engine from overload when the output shaft is braked. This drive guarantees optimum conditions of work for the engine regardless of the changing of load, and smoothly changes output speed according to the load. Mostly, design of this transmission consists of a pulsed mechanism with unbalanced inertial units and two overrunning clutches. The objects of the investigation are structural dynamic analysis of the continuously variable transmission. The physical and mathematical models of this transmission are developed.

The inertial continuously variable transmissions are mechanical transmissions that are based on the principle of inertia. These transmissions have a lot of advantages. Usually, the design of the inertial continuously variable transmissions consists of inertia pulsed mechanism with unbalanced inertial elements and two overrunning clutches. Dynamics of the transmissions is described by systems of substantial nonlinear differential equations. In general, precise methods of solution for such equations do not exist. Therefore, in practice, approximate analytical and numerical methods must be employed. The main analytical methods employ successive approximation, a small parameter, or power series expansion. Each approach has its advantages and disadvantages. Therefore, we need to compare them in order to select the best method for dynamic study of such kind of transmissions.

In this paper, we consider a new design of synchronous motor with salient poles rotor and all coils placed on the stator. This design, uses a laminated silicon steel rotor, which is not so expensive as a rotor with super strong permanent magnets. This design of machine eliminates copper rings on the rotor and brushes which is used in regular synchronous motors, and eliminates disadvantages involved with these arrangements. In an earlier publication, authors considered the opportunity realization of synchronous mode operation in the machine with salient pole rotor and DC stator excitation. Now, we consider the new synchronous mode operation with individual DC excitation of each the alternative current (AC) windings for realization the first, second and third phase synchronous machines. In theoretical basics of analyses and design of synchronous motors we pay more attention to the single-phase motor because it is the basis for design polyphase synchronous machines.

Overrunning clutches are devices for transmitting rotary motion in one direction only. These mechanisms are widely used in automotive industry, for example, in torque converters, impulse stepless transmissions, inertial continuously variable transmissions, starter engine starting system, and in other similar devices, where torque transmission is performed only in one direction. There are many different designs of the overrunning clutches, for example, ball, roller, cam, ratchet, spring ones, etc. But despite such a variety of designs and great efforts to establish reliable overrunning clutches, these mechanisms are still the weakest parts of many drive systems. Therefore, creation of reliable overrunning clutches is an urgent problem of mechanical engineering. Unfortunately, existing designs of the overrunning clutches have insufficient reliability and durability, which in many cases limits reliability of drive as a whole.

The main indicators for mobility of a multipurpose wheeled vehicle are the maximum and average technical velocity (it is defined as the distance traveled divided by the time elapsed), and they are mainly determined by power-to-weight ratio and the parameters of the suspension. As our analysis shows, with the increase of the power-to-weight ratio of the vehicle and its weight, the growth rate of the velocity is reduced, and after reaching a certain value, the velocity remains almost constant. This is due to the fact that for operating conditions of the multi-purpose wheeled vehicle, movement on roads with different degrees of uneven distribution of the rolling resistance and adhesion, in both transverse and longitudinal directions, is typical.

The main indicators for mobility of a multipurpose wheeled vehicle are the maximum and average technical velocity (it is defined as the distance traveled divided by the time elapsed), and they are mainly determined by power-to-weight ratio and the parameters of the suspension. As our analysis shows, with the increase of the power-toweight ratio of the vehicle and its weight, the growth rate of the velocity is reduced, and after reaching a certain value, the velocity remains almost constant. This is due to the fact that for operating conditions of the multi-purpose wheeled vehicle, movement on roads with different degrees of uneven distribution of the rolling resistance and adhesion, in both transverse and longitudinal directions, is typical.

DC motors are the most controllable electrical machines but more complicated for fabrication, in comparison with induction motors having simplified design but more complicated for control. Regular DC motor contain excitation (field) coil on the stator and armature coil on the rotor. Armature coil connected with external voltage source by a mechanical commutator with brushes. This arrangement complicates fabrication of DC machine, increases its cost, lowered reliability, and demands regular maintenance. Electromagnets inside of the stator increase dimensions of DC motor. In DC motor with salient pole rotor, there are no coils on the rotor, and mechanical commutator with brushes is eliminated, and eliminated all disadvantages connected with this arrangement. In this paper, we consider the new version of DC machine with DC stator excitation in compare with presented earlier. The difference is in using individual coil excitation for each armature coil, placed on the stator.

In this paper, we consider the hybrid power train for transportation of long pipes with big diameter. It is includes diesel engine for main towing vehicle and auxiliary electric drive for the active trailer The trains with active trailers are necessary at the building of oil and natural gas pipelines in no road conditions and marshlands. Due to the electric drive, the trailer's off-road capability on marshland conditions is sharply increased and its control is facilitated. The specified attractive qualities are appeared, if wheels of the trailer are executed as drivable, and the kinematic circuit of a drive is fulfilled as one-stage. At this, it is taken in attention that power of the electric drive will take 20 - 25 % from rated power of the basic traction drive, with the expanded range of torque control (till 1:10 and more). Such overloads are provided by the electric drive with synchronous reluctance machine of independent excitation developed by authors.

The main indicators for mobility of a multipurpose wheeled vehicle are the maximum and average technical velocity, and they are mainly determined by power-to-weight ratio and the parameters of the suspension. As our analysis shows, with the increase of the power-to-weight ratio of the vehicle and its weight, the growth rate of the velocity is reduced, and after reaching a certain value, the velocity remains almost constant. This is due to the fact that for operating conditions of the multi-purpose wheeled vehicle, movement on roads with different degrees of uneven distribution of the rolling resistance and adhesion, in both transverse and longitudinal directions, is typical. In this investigation we evaluate the effectiveness of the main methods of power distribution among drive wheels of the multi-purpose wheeled vehicles.

Free-wheel mechanisms transmit rotary motion in only one direction. They are widely used, for example, in hydraulic transformers, pulsed continuous transmissions, inertial automatic torque transformers, electrical starters for motors, and metal- and wood-working drives. Unfortunately, existing free-wheel mechanisms are insufficiently reliable and durable and in many cases limit the reliability of the drive as a whole. Thus, the insufficient life of free-wheel mechanisms delays the use of inertial automatic continuous transmissions, which have many benefits over existing transmissions. In most known free-wheel mechanism, the whole torque is transmitted through locking elements such as balls, rollers, eccentric wheels, pawls, slide blocks, and wedges, whose operation at large loads may limit the life of the mechanism.