Ondrej Cerny

FOC and flux weakening for traction drive with permanent magnet synchronous motor

This paper analyses control algorithm for permanent magnet synchronous traction motor (traction PMSM) usable for light rail vehicle. The algorithm is based on field oriented control. The field oriented control and carrier based pulse width modulation allow simply implementation of flux weakening control algorithm. The flux weakening provides wider speed operation of traction drive with PMSM. Simulations and experimental results are given. For experiments we have used a special experimental stand with a prototype of tram traction PMSM. Power of the PMSM is 58 kW. Description of the stand is given in the paper too.

Control Algorithms for Permanent Magnet Synchronous Traction Motor

The paper deals with research of sturdy control algorithm for traction drive with permanent magnet synchronous motor (PMSM). Two design algorithms are described here. First algorithm is control of phase currents which are based on control of instantaneous value of current for all phases of motor. Second algorithm is represented by control of phase currents in d-q frame (Field Oriented Control). The algorithms, which are mentioned above, are compared in this paper. Simulations results of both algorithms and partial results from measurement of traction motor with PMSM are cited in this paper, too. The traction motor with nominal power 58 kW makes use of phase currents control.

Research of harmonic spectrum of currents in traction drive with PMSM

The paper deals with the significant results of the experimental research of the harmonic spectrum of currents and induced voltages at traction drive with permanent magnet synchronous motors (PMSM). The experiments were done in a special workplace with a real traction drive for wheel vehicles. The harmonic spectrums of currents were analyzed by a specialized device on the basis of a central measuring station. The knowledge of marked subharmonic components of stator winding currents is the most significant finding of these experiments. The frequencies of these components are given by multiples of frequency of mechanical speeds. The subharmonic components also pass to the dc current at an input site of the traction inverter. This fact is particularly important from the viewpoint of legislative requirements to electromagnetic compatibility (EMC) of drive with railway interlocking devices.

Processor TI 2812 as control base of permanent magnet synchronous motor

The paper deals with description of two tested control algorithms for permanent magnet synchronous traction motor (PMSM), which uses DSP TI 2812. The first of the algorithm was phase current control algorithm based on sinusoidal commutation of brushless DC motors. The algorithm was improved by induced voltage compensation to reach better transient behavior in higher frequencies. The second algorithm was classical field oriented control. Both algorithms have used carrier based pulse width modulation. That could create problems from EMC point of view. Simulation and experimental results with processor TI 2812 are given.

The effects of faults at the distribution systems on the traction power supply systems

The paper deals with comparing the reliability and continuity of supply to traction power systems and compare it with the level of deliveries to all other customers in the distribution area of ČEZ Distribuce. It examines the causes of the disruption of clarity and also shows to the map. The present electric rail transport is very dependent on the continual electrical energy supply both for transport infrastructure and also for electric vehicles and units. In the case of traction energy supply faults the transport of electric drive vehicles will be stopped and the diesel rail vehicles have to be used for rail transport. This situation is incomparable with road transport due to many aspects. These traction power supply systems are highly dependent on the properties of distribution systems. For this reason, the stricter conditions in comparison with industrial systems are required. The characteristic consumptions and their variabilities during tens of seconds at traction systems, which is given by transport technology and management, are represented completely different sources of interference for other devices and systems.

The behavior of traction system of AC 25 kV during operation

The paper deals with behavior of Czech traction power supply system of AC 25 kV. The main goal of this paper is analysis of transient effects during operation of traction vehicles in various modes which can arise during short-circuits in traction system. The protection settings have to be done for all possible states in traction system including identification of short-circuits in the case of recuperation vehicle and protections on the board of this vehicle, which have to be able to detect these short-circuits and also the large voltage drops at catenary. The time of detection are given by safe touch voltage. At the present this problem is studied only by simulations in the given range with partial verification of results by real measurements due to technical and financial costs. The method of solution including parameters of elements of traction circuit is mentioned in this paper as well.

The sophisticated routing control of the bogie

The paper deals with the problems of improving of vehicle characteristics with the new conception of bogies. The goal of research activities is wear reduction of rail wheels and tracks, wear reduction of traction energy losses and increasing of running comfort. For this purpose the experimental rail vehicle with special construction including control algorithms for routing optimization of bogie powered by traction battery is utilized. This vehicle has a rotary bogie with independent rotating wheels driven by permanent magnets synchronous motors and a solid axle. The designed testing control is implemented to the superset control system of this experimental rail vehicle. The traction requirements and curve track radius have an effect to the control. The wheel forces in bogie are measured by large number of the tensiometric sensors and other various vehicle sensors for evaluation of testing control effect. This control including sophisticated routing is verified and corrected according to individual traction and driving characteristics.

Experimental research at traction PMSMs

The paper deals with the significant results of the experimental research of the harmonic spectrum of currents and induced voltages at traction permanent magnet synchronous motor (PMSM). The experiments were done in a special workplace with a real traction drive for wheel vehicles. The current harmonic spectrums were analyzed by a specialized device on the basis of a central measuring station. The knowledge of marked subharmonic components of stator winding currents is the most significant finding of these experiments. The frequencies of these components are given by frequency multiples of mechanical speeds. The subharmonic components also pass to the DC current at an input site of the traction inverter. This fact is particularly important from the viewpoint of legislative requirements to electromagnetic compatibility (EMC) of drive with railway interlocking devices.

Flux weakening effect of permanent magnet traction motor to its operating characteristics

The paper brings torque, power, efficiency and harmonic analyses of traction drive with permanent magnet synchronous motor (PMSM) during flux weakening operation. There is one way to weak flux of rotor permanent magnets — armature reaction caused by negative flux producing current component. On the other hand, the flux producing current component increases total RMS value of stator current. This effect has influence on losses and efficiency of PMSM. The paper investigates power, efficiency, torque and current characteristics in various operation points of PMSM drive. The analyses are realized on the bases of measurements performed on a special testing stand with PMSM 58 kW.

EMC of converters used at interlocking device

The paper deals with problems of electromagnetic compatibility (EMC) of frequency control drive of electromotive switch actuator of railway switch. The frequency converter with Pulse Width Modulation (PWM) and the output sinus filter are used for feeding of the asynchronous motor of the switch actuator. This drive is operated in isolated system of feeding voltages. The drive is fed by frequency converter with unshielded cable with length up to 1.2 km. The EMC problems occurring at development and operating of drive are analyzed in this paper. The second version of contactless safe switch, which works without PWM, is presented at the end of this paper.