Sharif Digital Repository

Plug-In hybrid electric vehicles could be connected to the electrical grid to be recharged. To ease the charging process, one solution could use an on-board charger to charge the electric vehicle battery. This charger should be able to be connected to a conventional outlet for convenience reasons and moreover, it should be a grid friendly charger in order not to pollute the electrical network. Since most of the electric vehicle related projects are at their initial phases, keeping up with the pace and developing new technologies and proposing innovations and concepts will help growing the industry. In this regard, a new integrated bidirectional isolated soft-switched plug-in hybrid electric... 

The LLC resonant converter, as a promising solution for battery charger applications, has the ability to adjust its output voltage during Constant Current and Constant Voltage modes in the charging profile. However, its operation mode changes as switching frequency changes. Therefore, for efficiency-oriented optimizations in battery charger applications, the one-pointed efficiency is not an appropriate objective. To this end, in this paper, a multi-pointed averaged efficiency is considered for optimization along with the transformer volume. Another factor of a proper design for a wide output range LLC is the converter peak voltage gain that is calculated based on an accurate method. The... 

In this paper a novel structure of a zero- voltage transition PWM boost converter is proposed. The main switch and diode of the converter are turned on and off under zero voltage transition. In addition the auxiliary switch and both diodes operate in ZCT condition. The auxiliary circuit consists of a transformer, a snubber capacitor and two diodes. Without imposing much current stress, the switching loss reduces significantly. So a higher efficiency converter is achieved. The simple structure and a wide range of operating current are the advantages of the proposed converter, which make it useful for solar battery chargers etc. The operation principles of the proposed converter are explained... 

An analog circuit for maximum power point tracking of a PV battery charger with minimum number of elements is proposed which works in a full range condition with a fixed switching frequency. In conventional MPPT algorithms which provide PV current or voltage reference value as output, fast climate changes may cause system instability. Here, a new variable is defined to eliminate the problem and improve the stability of the system. In order to compare the presented circuit with a conventional system, perturb and observe (P&O) MPPT algorithm which is well-known in PV systems is implemented on the same system. Simulation results (Conventional P&O algorithm and proposed structure) are presented... 

Battery chargers are fundamental components for successful deployment of plug-in hybrid electric vehicles (PHEVs) into future smart grid. Recently, an integrated isolated bidirectional battery charger has been proposed for PHEV applications. The proposed charger eliminates the conventional bulky dc-link capacitor by feeding a dual-bridge resonant tank directly from the three-phase grid. The disadvantages associated with the presented charger are the high number of semiconductor switches which contribute to high cost and switching losses of converter as well as complicated control circuitry. In this paper, the previous structure is modified to address the aforementioned drawbacks and is... 

Battery and plug-in hybrid vehicles equipped with bidirectional battery chargers are capable of supplying power to the electric grid according to power system demand. This technology is called 'vehicle to grid' or V2G. A bidirectional on-board charger can be used to improve the charge availability. An on-board charger should have small size and light weight. On the other hand, the charger must minimize power quality impact, draw current at high power factor to maximize power from an outlet. In this paper, a new three-phase integrated bidirectional isolated soft-switched battery charger is proposed which is appropriate for vehicle to grid technology. The charger utilizes a 4-switch...