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The urban trams with a low floor are more convenient for the passengers, and with a high floor - more cheaply and more technologically during manufacturing and operation. The combined advantages those and others in themselves are trams with average height of a floor, but for this purpose it is necessary to lower height of tram carriages, that is reached by application of electric motors with a small stator external diameter. It is offered in this the perspective electric drive on the base of the synchronous motor with independent excitation. The salient rotor poles of the motor do not contain windings. The motors stator is carried out on the base of the stator body of regular AC electric motor. The multiphase winding is located in the stator. A winding section, which conductors settle down above the between rotor poles, carry out a role of the excitation winding, and others, which conductors lay above poles, - a role of the armature winding.

The field regulated reluctance machine is perspective for automotive transport electric drives. In this machine, the switching of a stator current is done in function of a rotor position. The massive salient rotor of the electric machine does not contain windings. The stator is fulfilled in the body and iron of serial ac induction motor. The stator winding sections, which conductors lay above between rotor poles intervals, serve as a excitation winding, and others sections, which conductors lay above rotor poles, the role of a armature winding. In most cases, the optimal winding current waveform is distinct from the sine waveform. For a case of use separate current sources for each phase, the ideal is rectangular waveform. At the rotation of the motor, the each stator section winding pass from a zone of “excitation” to a zone of “armature”. The stator has finite number of phases.

The internal combustion engine gradually concedes the positions of traction unit. The electric drive including the electric motor, electro-generator, and diesel installation, comes on its change. The vector pulse control system of the wound rotor induction motor drive can be one of the perspective variants of such electric drive. The speed control of wound rotor induction motor with thyristor converter, assembled on base of three phase bridge circuit, is considered in report. The entrance circuits of the converter are connected to AC generator through motor stator windings, and converter output circuit (on the side of the dc voltage) connected to a two rotor windings connected in series. The third rotor winding can be connected in parallel or remain free. The stator magneto-motive force is created by switching thyristors. Magneto-motive force is rotating discretely with a step of 60 degrees.

As a rule, the work of electric drives of transport mechanisms arises with variable load and with different control laws of torque and speed. That leads to redistribution of losses components and demands take it in attention. In the report, the character change of the general losses and their components are compared in different type of electric drives under change of the load. In connection with this, it is paid attention to features of redistribution of losses in the perspective for transport mechanisms electric drive with field regulated reluctance machine. This machine is characterized by increased reliability, high specific parameters, simplicity of a design and control, and opportunity work in aggressive conditions. The opportunity realization of control laws in the electric drive with reluctance machine (with independent excitation) the same as in the electric drive of direct current machine makes perspective comparison of losses in these electric drives.

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.

The paper solves the problem of increasing the accuracy of measuring torque and use of an electronic torque meter as a feedback sensor of synchronous and induction machines of an electric traction drive. Relevance of the problem and methods for its solving by indirect means using simulation models of electric machines are considered. The theoretical development of the meter is based on the energy model of electric machines in the form of differential equations for active and reactive power balance. This eliminates the direct influence of instability and nonlinearity of inductive elements and takes into account electrical, magnetic, mechanical, and harmonic losses using the simplest algorithms. Key variables of the model in the form of total active power and angular velocity are measured directly, and the high nominal efficiency of traction machines (95%) provides a wide tolerance range for calculating total losses.