Martin Pittermann

New Configuration of Traction Converter With Medium-Frequency Transformer Using Matrix Converters

This paper presents a new configuration of a main traction converter with a medium-frequency transformer (MFT) using matrix converters intended for locomotives and particularly for suburban units supplied by a 25-kV/50-Hz and/or 15-kV/16.7-Hz ac electrification system. Single-phase matrix converters are employed in the primary medium-voltage converter which is directly connected to the ac trolley line. The output of the primary ac/ac converter supplies the primary side of the MFT. The proposed MFT-based topology of the traction converter replaces the bulky main line transformer found on board railway vehicles. Particularly in countries with a catenary of 15 kV/16.7 Hz, very low catenary frequency results in huge and heavy traction transformers. The developed topology is a power electronics solution that considerably reduces weight and losses in a traction propulsion system. The proposed converter configuration with cascaded matrix converters on the primary side of the MFT presents a new research direction in the field of traction converters with MFTs. This paper describes in detail the proposed power circuit and the control of the traction converter. The behavior of the traction converter configuration has been analyzed using simulations and experimental tests carried out on a developed low-voltage laboratory prototype of a traction converter with a rated power of 4 kVA. Based on extensive simulation and experimental study, this paper reviews the benefits, drawbacks, and constraints of the developed traction converter configuration.

Novel primary high voltage traction converter topology for multi-system locomotives

This paper presents research motivated by industrial demand for special traction drive topology devoted to minimization of traction transformer weight against topology with classical 50Hz traction transformer. The main attention has been given to the special traction drive topology for AC power systems: input high voltage trolley converter (single phase) —middle frequency transformer (single phase) — output converter (single phase voltage-source active rectifier + three phase voltage-source inverter) - traction motor. The proposed converter control algorithm of innovative traction topology with middle-frequency transformer has been described in detail. The theoretical conclusions and simulation results are compared with experimental measurements on laboratory model with rated power of 4kVA.

The traction drive topology using the matrix converter with middle-frequency transformer

This paper presents research motivated by industrial demand for special traction drive topology devoted to minimization of traction transformer weight against topology with classical 50 Hz traction transformer. The main attention has been given to the special traction drive topology for AC power systems: input high voltage trolley converter (single phase matrix converter) - middle frequency transformer - output converter (single phase voltage-source active rectifier + three phase voltage-source inverter) - traction motor. The control algorithm (Inserting of NULL vector of matrix converter, Two-value control of secondary active rectifier, PWM and etc.) of innovative traction topology with middle-frequency transformer has been described.

The study of using the traction drive topology with the middle-frequency transformer

This paper presents research motivated by industrial demand for special traction drive topology devoted to minimization of traction transformer weight of traction vehicles. The main attention has been given to the special traction drive topology for AC power systems: input high voltage trolley converter (single phase) - middle frequency transformer (single phase) - output converter (single phase voltage-source active rectifier + three phase voltage-source inverter) - traction motor. This configuration can minimize traction transformer weight against topology with classical 50 Hz traction transformer. Several variants of innovative topologies of the traction vehicles fulfill the weight reduce requirements have been presented.

High voltage matrix converter topology for multi-system locomotives

This paper presents research motivated by industrial demand for special novel high voltage traction drive topology devoted to minimization of traction transformer weight against classical locomotives operates on both trolley voltages of 25kV/50Hz and 15kV/16⅔Hz. The main attention has been given to the special traction drive topology for AC power systems: input high voltage trolley line converter (single phase matrix converter) - middle frequency transformer - middle voltage output traction converter (1f active rectifier+3f VSI) - traction motor. This contribution describes in detail proposed new control strategy of novel high voltage traction drive topology with single-phase matrix converter using controller of the phase shift angle between the trolley wire voltage and current. Input high voltage converter consists of several matrix converters to spread input high trolley voltage to each matrix converter. The theoretical conclusions and simulation results of serial matrix converters connection are compared with extensive series of experimental measurements on laboratory model with rated power of 4kVA.

Control algorithms of additional converter for reducing the impact of voltage sags to typical electric drive

This paper deals with problems of line voltage sags and its impact on typical electric drive with induction motor supplied from the indirect frequency converter. It describes one of possible modifications of the power circuit to eliminate the impact of line voltage sags. The article also discusses different options of control circuits and their impact on the system behavior. There are also presented the measurement results of real laboratory system and shows some waveforms of selected transient phenomena.

Primary traction converter for multi-system locomotives

This paper presents research motivated by industrial demand for special traction drive topology devoted to minimization of traction transformer weight against topology with classical 50 Hz traction transformer. The main attention has been given to the special traction drive topology for AC power systems: input high voltage trolley converter (single phase) - middle frequency transformer (single phase) - output converter (single phase voltage-source active rectifier + three phase voltage-source inverter) - traction motor. The proposed converter control algorithm of innovative traction topology with middle-frequency transformer has been described in detail. The theoretical conclusions and simulation results are compared with experimental measurements on laboratory model with rated power of 4 kVA.

Single phase high-voltage matrix converter for traction drive with medium frequency transformer

This paper describes the realization variants of the new traction drive for AC-power system with high-voltage matrix converter and medium frequency transformer (i.e. MFT). These topologies allow minimizing the weight of the traction transformer in railroad vehicles. Special attention is given to serial connection of input single-phase high voltage matrix converters fed MFT transformers. The control method involving the reduction of MFT magnetic saturation has been discussed.

Traction Drive with MFT - Novel Control Strategy Based on Zero Vectors Insertion

Abstract This paper presents research motivated by industrial demand for special novel high voltage traction drive topology devoted to minimization of traction transformer weight against classical locomotives operates on both 25kV/50Hz and 15kV/16⅔Hz trolley voltages. The traction converter topology consists of: two single phase matrix converter + medium frequency transformer (MFT) + single phase voltage-source active rectifier. Measured results of steady state and selected transient states verifying of proper function of control algorithms. The new control strategy of traction converter based on zero vectors insertion has been proposed to smoothing taken trolley current.

The comparison of different variants of new traction drives with medium frequency transformer

This paper describes different variants of realization of new traction drive for AC- power system based on medium frequency transformer MFT. These topologies enable to minimize weight of traction transformer. Basic variants of input high voltage converter realization (using modular multilevel converter MMLC, indirect frequency converter with VSI, matrix converter or other direct frequency converter) have been compared. For these basic variants the modifications are solved (with different power circuits and with different control algorithms). Special attention is given to single-phase high voltage matrix converter with input filter used serial connection of capacitances (realized in laboratory).