Chen Jingwei

Modeling of PM-PM Dual Mechanical Ports Electric Machines

A dual mechanical ports electric machine (DMPM) is presented firstly, which is a special motor with two mechanical ports and two air gaps. The disadvantage of traditional model of DMPM is analyzed without considering the magnet coupling between two air gaps, which will affect the precision greatly. Consequently a new modeling scheme is presented and a model of permanent magnet DMPM is deduced. First, the inductance matrix of the motor is calculated in the natural frame, based on which the model of the special motor is obtained in the synchronous reference frame. Then, the simulations are carried on the new model and traditional model. The results prove that the two models have great difference, so the magnet coupling of two air gaps cannot be neglected

Permanent magnet dual mechanical port machine design for hybrid electric vehicle application

The dual mechanical port (DMP) machine is a new breed machine with two rotors. Because the two rotors can run at different speed, the DMP machine functions as both a pair of motors and an electrical variable transmission system. When it is used in hybrid electric vehicle, it can perform all the functions as Toyota Hybrid System does, but with more compact and integrated structure [1]. In hybrid vehicle application, dasiaratedpsila power and torque have different meanings from those in fans and pumps. In this paper, a new method to define the DMP machine specifications is proposed. The interaction between different flux loops is analyzed by FEA. A DMP machine prototype is developed. Experiments conducted verify the design.

Simulation of an electrical variable transmission based on dual mechanical ports electric machine with clutch

A dual mechanical ports electric machine (DMPM) with clutch is used as an electrical variable transmission (EVT) in hybrid electric vehicle (HEV), as presented in, which can eliminate copper loss and iron loss in the inner motor when clutch is engaged. In this paper, the EVT system simulation model including the models of DMPM, clutch, internal combustion engine (ICE) and controller together, is constructed. The dynamic performance of the system such as the engaging or disengaging process of clutch, the ICEpsilas startup or stop are analyzed under FTP75. Simulation results show that there is an impact torque, which is equal to output torque of ICE, on the outer motor of DMPM at the moment of ICEpsilas startup and the immediate speed increase of ICE in opposite direction due to the sudden decrease of ICEpsilas load when the clutch is disengaging, which should be avoided when the HEV with EVT based on DMPM with clutch is in practical application.

Characterization of the nanosized porous structure of black Si solar cells fabricated via a screen printing process

A silicon (Si) surface with a nanosized porous structure was formed via simple wet chemical etching catalyzed by gold (Au) nanoparticles on p-type Cz-Si (100). The average reflectivity from 300 to 1200 nm was less than 1.5%. Black Si solar cells were then fabricated using a conventional production process. The results reflected the output characteristics of the cells fabricated using different etching depths and emitter dopant profiles. Heavier dopants and shallower etching depths should be adopted to optimize the black Si solar cell output characteristics. The efficiency at the optimized etching time and dopant profile was 12.17%. However, surface passivation and electrode contact due to the nanosized porous surface structure are still obstacles to obtaining high conversion efficiency for the black Si solar cells.

The investigation of ZnO:Al2O3/metal composite back reflectors in amorphous silicon germanium thin film solar cells

Different aluminum-doped ZnO (AZO)/metal composite thin films, including AZO/Ag/Al, AZO/Ag/nickel—chromium alloy (NiCr), and AZO/Ag/NiCr/Al, are utilized as the back reflectors of p—i—n amorphous silicon germanium thin film solar cells. NiCr is used as diffusion barrier layer between Ag and Al to prevent mutual diffusion, which increases the short circuit current density of solar cell. NiCr and NiCr/Al layers are used as protective layers of Ag layer against oxidation and sulfurization, the higher efficiency of solar cell is achieved. The experimental results show that the performance of a-SiGe solar cell with AZO/Ag/NiCr/Al back reflector is best. The initial conversion efficiency is achieved to be 8.05%.