Jakub Talla

Position-Based T-S Fuzzy Power Management for Tram With Energy Storage System

Energy storage systems (ESSs) play a significant role in performance improvement of future electric traction systems. This paper investigates an ESS based on supercapacitors for trams as a reliable technical solution with considerable energy saving potential. Operating the ESS onboard a tram brings the following benefits: reduction of peak power demands, decrease of power consumption, improvement of performance, and efficiency. Whereas the commonly used ESS power management (PM) has been dealing only with PM without vehicle position knowledge, the main emphasis of the presented research is put on position-based Takagi-Sugeno fuzzy (T-S fuzzy) PM for human-driven trams with an ESS. The tram position, located by, e.g., a Global Positioning System module, is used to predict future energy demands and power flows. This information is used in the preparation of the supercapacitor energy level and its power flow control. The optimal ESS power flow with respect to the tram position is a very complex problem. Therefore, soft computing techniques are used in this paper. The main part of the proposed ESS PM is the T-S fuzzy controller. The T-S fuzzy reduces problem dimensionality using expert knowledge represented by the rules. The output membership functions were optimized by differential evolution. The designed ESS PM was verified on real traffic data.

Current reference generator for single-phase shunt active power filters based on MGP-FIR

This paper describes three implementation alternatives of a multiplicative general parameter finite impulse response filter (MGP-FIR) used as a precise current reference generator for shunt-type active power filters. Compared to the traditional techniques that use fixed digital or analogue filters, the MGP-FIR is an adaptive and predictive algorithm for tracking typical frequency variations and thus avoiding the harmful phase shift of the fundamental sinusoid. This characteristic is essential for maximizing the harmonics reduction ability of the active power filter. The fixed subfilters of the MGP-FIR are pre-optimized by the use of a genetic algorithm. The harmonics reduction ability was verified by extensive simulations. Moreover, a laboratory prototype was developed and experimentally tested under typical non-linear loads. Compared to the previously presented articles on MGP-FIR-based current reference generators, this is the first time when real-valued or fixed-point coefficients are used with the MGP-FIR. In addition, we also improved the originally proposed amplitude detector. The results are compared with those presented earlier.

Elimination of dead-time effect causing current distortion of single-phase power converters

This paper describes constraints created by dead-times in single-phase voltage-source inverters working with medium and high switching frequencies (over thousands of Hertz). The dead-times cause distortion of a current at a converter ac side which is not acceptable especially in applications requiring high-precision current control. The control of voltage-source converter presented in this paper uses vector control in Cartesian coordinates which is offers very good dynamic properties. However, it is not able to naturally compensate the dead-time effects. Therefore, we complete this control by dead-time compensation block mitigating the unwanted distortion of converter ac current caused by dead-time effects using a nonlinear function generator. The behaviour of inverter control with proposed dead-time compensation and without compensation is reported in this paper.

Stochastic tram model based on real traffic data for energy storage system designing

This paper describes the stochastic tram model development on a real traffic data. The trams traffic data are measured on the tram without energy storage system in Pilsen (Czech Republic). The model can reliable simulate power flow, line losses and energy storage system efficiency for trams with supercapacitors.

Advanced Control Strategy for Single–Phase Voltage–Source Active Rectifier with Low Harmonic Emission

Abstract This paper introduces the advanced control of single-phase voltage-source active rectifier. This control provide direct control of trolley-wire current and active damping of low-frequency disturbances at the converter ac side. Our proposed control strategy combines PR controller with feed-forward model and low-frequency harmonic compensator based on resonant controllers. Achieved experimental results show excellent converter behavior, where converter is fed by strongly distorted supply voltage.

Fuzzy energy management strategy for tram with supercapacitors

Energy storage systems (ESS) have large impact on efficiency and reliability of modern electric traction systems. This paper investigates the fuzzy energy management strategy for ESS based on supercapacitors (SC) for human driven trams. Operating the SC on board of a tram brings the following benefits: reduction of peak power demands, decrease of power consumption, improvement of performance and efficiency. Whereas the commonly used ESS Energy management strategies (EMSs) have been dealing without knowledge of vehicle position, the main interest of the presented research is put on the algorithm using the Global Positioning System (GPS). The tram position, located by a GPS module, is used to predict future energy demands and power flows. This information is used in the preparation of the supercapacitor energy level and its power flow control. The optimal ESS power flow with the respect to the tram position is a very complex problem. For this reason, soft computing techniques are used in this paper. The main part of the proposed ESS EMS is the Takagi-Sugeno Fuzzy controller (T-S Fuzzy). The T-S Fuzzy reduces problem dimensionality using the expert knowledge represented by the rules. The output membership functions were finaly optimized by the Differential Evolution (DE).

Current Source Based on H-Bridge Inverter with Output LCL Filter

Abstract The paper deals with a control of current source with an LCL output filter. The controlled current source is realized as a single-phase inverter and output LCL filter provides low ripple of output current. However, systems incorporating LCL filters require more complex control strategies and there are several interesting approaches to the control of this type of converter. This paper presents the inverter control algorithm, which combines model based control with a direct current control based on resonant controllers and single-phase vector control. The primary goal is to reduce the current ripple and distortion under required limits and provides fast and precise control of output current. The proposed control technique is verified by measurements on the laboratory model.

Control of single-phase AC/DC converter based on SOGI-PLL voltage synchronization

This paper introduces the advanced control designed for the single-phase AC/DC traction converter. This type of control provides direct current control and sufficient control of output voltage. The proposed control strategy is based on second order general integrator phase locked loop (SOGI-PLL), which is used for trolley voltage synchronization. In this case SOGI-PLL evaluates voltage position, amplitude and frequency. These data are used for precise and robust current control, which uses PR controller. The behavior of designed control and SOGI-PLL synchronization is analyzed by both simulations and experiments made on developed 1.5 kW laboratory prototype.

Genetic algorithm based optimization of MGP-FIR current reference generator for active power filters

This paper describes genetic algorithm (GA) based optimization of multiplicative general parameter finite impulse response filter (MGP-FIR) current reference signal generator for shunt-type active power filters. The MGP-FIR consists of two fixed subfilters with GA’s preoptimized fixed-point coefficients sharing one common delay line and two general adaptive multiplicative parameters to avoid harmful phase shift during fundamental frequency fluctuations. Presented theoretical conclusions are verified by simulation results and experiments performed on a designed laboratory prototype of the single-phase active power filter.

Control of a Single-Phase Cascaded H-Bridge Active Rectifier Under Unbalanced Load

Cascaded H-bridge (CHB) converter technology is actually the most popular solution for grid-connected converters in both medium- and high-voltage applications. This paper introduces a new control of a single-phase CHB active rectifier. The control uses a direct grid current control based on adaptive resonant controllers. The resonant controllers are adapting to slow fluctuation of ac grid frequency. The challenging problem of CHB converters is dc-link capacitor voltage balancing especially under unbalanced load conditions. This paper presents a reliable voltage-balancing technique utilizing energy estimation of particular dc-link capacitor banks and simple prediction of the changes of their energies. A nonlinear behavior of the converter caused by power semiconductors voltage drops and dead-time effects is minimized by auxiliary adaptive resonant controllers. The resulting control has very good performance, including the operation under unbalanced load conditions, and achieves low total harmonic distortion of converter grid current. The theoretical results were verified by experiments made on the developed CHB active rectifier prototype with three power cells in cascade.