Seyyedmilad Ebrahimi

Integrated bidirectional isolated soft-switched battery charger for vehicle-to-grid technology using 4-Switch 3Φ-rectifier

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 3Φ-rectifier as the front-end AC/DC converter and a phase-shift controlled dual bridge series resonant as the rear-end DC/DC converter. The performance of the proposed charger is investigated by simulation results.

Output voltage quality intensification of diode clamped multilevel inverters using FM PWM technique

Improvement in switching techniques is one of the effective methods for increasing the voltage quality in Multilevel Inverters. In this paper, a novel switching technique using frequency modulation is proposed to achieve high quality output voltage of multilevel inverters. This method is employed to different configurations of multilevel inverters consist of Diode Clamped (or Neutral Point Clamped), Flying Capacitor and Cascaded H-bridge. Each multilevel inverter which utilizes this technique is modeled and simulated to investigate the performance of this method by the help of MATLAB/Simulink software. The Results show that this innovative method considerably reduces total harmonic distortion (THD) of output voltage for diode clamped multilevel inverters in different kinds of loads and can solve the problem of transferring the active power in this type of inverters.

A single-phase integrated bidirectional plug-in hybrid electric vehicle battery charger

Plug-In hybrid electric vehicles could be connected to the electrical grid to be recharged. To ease the charging process, one can use an on-board charger to charge the electric vehicle battery. The on-board charger should have small size and light weight. On the other hand, the charger should draw current at high power factor to maximize power from an outlet. Most of the existing battery chargers are unidirectional which cannot be used in smart grid for vehicle-to-grid (V2G) purpose. In this paper, a new bidirectional isolated soft-switched battery charger is proposed which is appropriate for vehicle to grid technology. This proposed structure shares the same hardware components which are used in motor-inverter for traction mode, therefore there is no additional components used and inverter/charger systems are integrated. Hence, the size of the whole charger/inverter will be decreased. This charger utilizes a phase-shift controlled dual bridge series resonant DC/DC converter which benefits isolation which is vital in terms of safety issues as well as soft-switching operation for its semiconductor switches. The appropriate performance of the proposed charger is investigated by simulation and experimental results.

An Isolated Bidirectional Integrated Plug-in Hybrid Electric Vehicle Battery Charger with Resonant Converters

Abstract Plug-in hybrid electric vehicles draw electricity from the electrical grid and store energy in their batteries. To increase charge availability for plug-in hybrid electric vehicles, on-board chargers can be used, which should be small in size and lightweight. In this article, an on-board bidirectional soft-switched battery charger is proposed that utilizes a phase-shift-controlled dual-bridge series resonant converter with isolation. The bidirectional characteristic of proposed charger makes it suitable for vehicle-to-grid operation (i.e., injecting power from the vehicle to the grid) in smart grids. A switching control scheme is also proposed to provide soft-switching operation for all semiconductor switches, resulting in high efficiency for the charger. In this structure, the conventional bulky capacitor of the DC link is eliminated. In addition, the proposed charger can integrate the hardware of the traction system; hence, the size of the whole charger–inverter system will be drastically decreased. The appropriate performance of the proposed charger is verified by simulation and experimental results.

Performance comparison between brushless PM and induction motors for hybrid electric vehicle applications

Hybrid electric vehicles are becoming more popular due to environmental consciousness. Hybrid electric vehicles consist of a combustion and an electric motor. In practice, the effect of selecting appropriate electric motor is observable on all the main indices of vehicle performance such as maximum speed, gradeability, pollutant emission, fuel consumption, etc. Different studies have been done to compare various electric machines operating as motors or generators. However, investigating the performance of electric motors as electric traction systems in hybrid electric vehicles has not been emphasized in literature. In this paper, the performance of two induction and PM motors have been investigated in hybrid vehicle application through simulation results, benefiting ADVISOR software.

Reactive compensation investigation of TSC systems based on different power factor definitions

Accurate power factor definitions are of great importance for industries due to the fact that they affect the billing strategy. They also considerably affect the generation and distribution losses of the power system. At the moment, there are some ambiguities in power definitions to be used for this purpose. In recent years, because of a rapid growth in industry and the use of variable loads such as electrical furnaces and variable speed motors, there is a need for fast compensators that are capable of tracking load changes. One of these facilities is TSC, a capacitor bank that is controlled by static switches (thyristors). In this paper, the performance of these compensators in power factor correction for asymmetrical and variable loads in terms of PF-control capability, system losses and the THD of the input current based on various power factor definitions has been investigated, and a PF definition compatible with a commonly used control algorithm is proposed. Simulations have been carried out in PSCAD/EMTDC software environment.

Plug-in hybrid electric vehicle battery charger with soft-switched dual-bridge resonant converter for smart grid applications

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 controlled by a modified switching algorithms. The new proposed PHEV battery charger is verified mathematically and by simulation results to provide higher power density with lower switching stress and losses.

Performance improvement of steady-state and transient operation of offshore wind farm HVDC power transmission

Wind power generation is increasing fast as a clean renewable energy resource. Offshore wind farms are popular due to advantages such as higher and smoother wind speeds, less farm site limitations, etc. High capacitive currents and need to expensive compensations, make use of high-voltage-direct-current (HVDC) power transmission indispensable for longdistance wind farm power generations. Steady-state and transient performance improvements of HVDC systems have always been an interesting industrial and academic research area. In this paper, a novel control method is proposed to improve the steady-state operation of HVDC system. Moreover, a new fault detection scheme is proposed to improve the fault-ride-through capability of the system. The effectiveness of the proposed methods are verified against conventional control methods using simulation results.

A ZVS-resonant bifilar drive circuit for SRM with a reduction in stress voltage of switches

Switched Reluctance Motors (SRMs) are widely used in high-speed and low voltage applications because of their attractive features such as robustness and simplicity. No winding on the rotor of this type of motors allows reaching high speed which is desired for many applications. Drive circuits of SRMs also play an important role in their performance and operation. In this paper, a new bifilar drive circuit for this type of motors has been proposed. This novel configuration has been tested and investigated by PSIM software. Results show that the new bifilar drive circuit highly reduces the voltage stresses on semiconductor switches, and also considerably reduces the switching losses which are very important in low voltage applications. Finally, a comparison between this new drive circuit and some other common configurations is presented.