Different types of hybrid electric vehicles (HEVs) are manufactured by some auto manufacturers or developed by some researchers to improve fuel economy and reduce emissions. HEVs reduce the vehicular emissions, however, they are not able to deliver zero local emissions. Plug-in hybrid electric vehicles (PHEVs) are new types of HEVs that have more batteries, more powerful traction motors and the plug-in capability such that they can be operated in all-electric mode for a given distance and the batteries can be charged from the power grid. PHEVs have the potential to further increase the fuel economy and reduce the vehicular emissions of HEVs. This paper evaluates the advanced batteries for HEV and PHEV applications and develops equations to calculate the performance requirements and costs of different subsystems in a vehicle.
This paper presents a new switched-capacitor inverter circuit based on partial charging. A number of switched-capacitor inverter circuits have been developed, but most of them are based on switching of fully charged capacitors in specific sequence to generate staircase ac voltage. In order to reduce the output distortion, the numbers of capacitors and switches should be increased. However, complexity of the circuits will also be increased dramatically. Moreover, the number of capacitors of conventional switched-capacitor inverters should be limited, otherwise, the peak output voltage could exceed stipulated limit. The new switched-capacitor circuit operates in such a manner that the capacitors will be switched to generate an ac output while they are partially charged. Each capacitor can provide multilevel voltages because the state of charge is varied. Theoretically, ac voltage with unlimited steps can be created with a few of capacitors. Experiments and simulations of a thirteen-level inverter that consists of only two capacitors are included in this paper.
In this paper, a new four-quadrant (4Q) soft-switching converter for dc motor drives, namely the 4Q zero-current-transition (4Q-ZCT) converter, with the capabilities of 4Q power flow, and ZCT switching profile for dc motor drives is proposed. It has some definite advantages over their hard-switching counterparts and other soft-switching converters. Both the turn-on and turn-off losses of main switches are significantly reduced, while the auxiliary switches can always operate with zero-current-switching (ZCS). It possesses the advantages of reduced switching stresses, minimum voltage and current stresses as well as minimum circulating energy during both the motoring and regenerating modes. It also offers simple circuit topology, minimum component count and low cost.
Recently, the application of surface-mounted magnet brushless machines to EVs/HEVs is extensively researched. In this paper, the performance of such kind of brushless motor which has a trapezoidal back-emf waveform when operated in BLDC and BLAC modes is evaluated, in both constant torque and flux-weakening regions, assuming (a) the same torque, (b) the same peak current, and (c) the same rms current. It is shown that although the motor has an essentially trapezoidal back-emf waveform, the output power and torque when operated in the BLAC mode in the flux-weakening region are significantly higher than that can be achieved when operated in the BLDC mode due to the influence of the winding inductance and back-emf harmonics.
In recent years, battery-electric vehicles, hybrid-electric vehicles, fuel-cell vehicles or industrial inverters are being mass-produced which use DC high-voltage high-current. Because of this, a highly reliable electric relay, which assures the shutdown of circuits in a situation where the electric current exceeds 500A, has required development as a safety measure. A new type of electric relay for DC high-voltage high-current power is developed by applying a radial component magnetic field to the relay's contact point. Evaluation tests are conducted and the results indicate that the performance of the new relay is significantly higher in comparison to conventional products.
Lead-acid batteries have been used as a starter for tens of millions of cars in the world. They are also used as a cheap way to store energy for electric-powered vehicles, EV's. Life prolongation of these batteries is an important issue for resource conservation and the reduction of environmental contamination caused by discarded batteries. For this purpose, an organic battery activator named ITE (International Technology Exchange) activator has been exploited since 1996. This additive is an organic battery activator. The results of high-precision bench-tests, which are conducted in order to find an optimization of the activator's density, are described in this paper. The test results show that the best life-prolongation is achieved when an activator of 5Wt% with 10cc/cell is added for a starting battery of engine, 28Ah (10hrs).
This paper describes the development and performance of a compact, unmanned, radio-controlled electric vehicle. This vehicle is controlled by radio while it appears that a dog is the driver. The main purpose of this research is to show a dog driving a vehicle in order to conduct traffic safety campaigns, but this paper also describes the diversion of this development of autonomic robots for military purposes and its importance in relation to this research.
The new concept of charger for lithium ion battery assembly with several unit cells has been proposed and tested. The Cockcroft Walton (CW) circuit developed as a high voltage multiplier was applied for the battery charger of lithium ion battery assembly. The some capacitors in CW circuit were substituted with unit cells to design the charger circuit. This charger circuit worked well for the individual unit cell of integrated battery assembly. It is also considered that the wide application is feasible because of its simple circuit.