Javier Gallardo-Lozano

Hall-Effect Based Semi-Fast AC On-Board Charging Equipment for Electric Vehicles

The expected increase in the penetration of electric vehicles (EV) and plug-in hybrid electric vehicles (PHEV) will produce unbalanced conditions, reactive power consumption and current harmonics drawn by the battery charging equipment, causing a great impact on the power quality of the future smart grid. A single-phase semi-fast electric vehicle battery charger is proposed in this paper. This ac on-board charging equipment can operate in grid-to-vehicle (G2V) mode, and also in vehicle-to-grid (V2G) mode, transferring the battery energy to the grid when the vehicle is parked. The charger is controlled with a Perfect Harmonic Cancellation (PHC) strategy, contributing to improve the grid power quality, since the current demanded or injected has no harmonic content and a high power factor. Hall-effect current and voltage transducers have been used in the sensor stage to carry out this control strategy. Experimental results with a laboratory prototype are presented.

Three-phase bidirectional battery charger for smart electric vehicles

A three-phase battery charger for electric vehicles is proposed in this paper. The charger is bidirectional, allowing the Charging and Vehicle to Grid operation modes. A novel Balanced Sinusoidal Source Current control strategy is proposed so that the charger demands or injects into the grid a perfect sinusoidal and balanced source current in phase with the positive sequence fundamental component of the phase-to-neutral grid voltage, achieving a unity displacement power factor. In this way, the charger turns the car into a smart vehicle, reducing the existing problem of harmonic current demand by electric and hybrid vehicles and improving the power quality of the electric power system. The topology and control stage of the charger are shown. Simulation tests are conducted to validate the proper operation of the charger under sinusoidal, distorted and unbalanced source voltages.

Grid reactive power compensation by using electric vehicles

Along this paper, it will be presented how the Electric Vehicle (EV) bidirectional chargers can help the Distribution Grid. In addition to the battery charge and the Vehicle-to-Grid functions (V2G), the reactive power can be compensated according to an established reactive power reference. A three-phase bidirectional inverter connected with a DC link to a DC/DC bidirectional converter is utilized in the topology. The different modifications that are needed in the control algorithm and in the power stage are determined. Simulation results are shown, which prove how the reactive power is being compensated and the saturation of the reactive current is used to keep the power under predefined limits.

Active Battery Balancing for Battery Packs

Abstract In electric vehicle applications, it is necessary to use series strings of batteries since the required voltage is higher than the one that can be obtained from a single battery. Due to several factors, imbalance of batteries in these battery systems is usual and an important factor that has to be taken into account. Many balancing methods have been developed with a lot of different advantages, but all of them also have a lot of disadvantages such as complexity and/or high cost, which are the common problems that can be found in most of these equalization methods. In the present work, a low cost and very simple equalization method is proposed, in which a novel control is applied to a shunting transistor topology. It allows the transistors to regulate the amount of current that goes through each battery cell in the string depending on their State of Charge (SOC), during the charging process. This control ensures that the least charged cells to be charged faster, and the most charged ones to be charged more slowly. Design criteria are discussed and simulation results are carried out in a generic battery low power application which proves the control method. Fast equalization with a low complexity and cost is obtained

Optimized energy consumption management for residential applications controlled by a Local Energy Management Unit

Distribution Grid is evolving into the Smart Grid and users are playing a key role more and more. An efficient network is the aim and Energy Management Systems are being utilized in residential areas in order to contribute to reach this final mentioned goal. The Local Energy Management Unit is presented in this paper, which allows an optimized constant power demand to the Grid, demanding sinusoidal currents to the Grid which are in phase with the Grid voltage. Communications by using TCP and X10 protocols are used to control the whole system and a prototype, which is presented in this paper together with the obtained experimental results, is built to demonstrate the presented efficient energy management conclusions.

Electric vehicle multiport fast charger based on the concept of active power electronic transformer

This paper describes a new multiport fast charger for an electric vehicle based on the concept of the active power electronic transformer. Energy sources, chargeable batteries and storages are connected together via a common multi-winding transformer and simple full-bridge inverters. The theoretical control principles and the proposed topology are verified by computer simulations.

Battery Equalization Control Based on the Shunt Transistor Method

Abstract Electric Vehicle (EV) researches are currently becoming of special importance and the EV battery system is particularly relevant in the EV design. In these applications, series connected batteries are necessary since a single battery cannot achieve the voltage requirements. Internal and external sources lead the batteries string to become unbalanced, which is an important factor to be taken into account, as premature cells degradation, safety hazards, and reduced capacity will occur for unbalanced systems. The different balancing methods are presented and compared in this paper, and finally the switch capacitor and the double-tiered switching capacitor are considered the best option. However, their speed depends on the voltage difference between the batteries in the string, and when their voltage difference is low, the equalization speed decreases significantly, leading the battery pack to be unbalanced for longer. A novel equalization method is presented, that improves the aforementioned methods performance by applying a new control to a shunt transistor method. Low cost, size, and complexity, together with higher speed and efficiency are obtained. A prototype has been built, and experimental results are presented.

Optimization of Losses in Permanent Magnet Synchronous Motors for Electric Vehicle Application

The aim of this paper is to analyze the influence of some parameters related with the permanent magnet motor control, which are being considered as an attractive alternative for electrical vehicle application where it is important to minimize the losses to increase the vehicle autonomy. In this paper, the attention is focused on the selection of the speed controller parameters and its impact both in mechanical losses as in the corresponding torque-speed trajectories. Moreover, the dependency of the switching frequency over the total losses in the motor-converter device is shown. The analysis determines the optimum value for the switching frequency and the results are compared with commercial servos.

A battery cell balancing method with linear mode bypass current control

A study of a novel control method for a battery cell equaliser, based on the shunting transistor method is presented. The method allows cell balancing in both battery operating modes, recharging and driving modes. To verify the applicability of the method, computer simulation was conducted analysing how the system balances during a driving period, by following a real current profile measured from a real REVAi driving. The obtained results show how at the end of the driving period the system is already balanced, allowing a subsequent high speed charge and avoiding a later equalisation stage. Finally, the integration of the balancing system into a higher level system, based on a multiport converter topology is discussed.