Showing papers by "Yongjian Li published in 2009"

Drive system analysis of a novel plug-in hybrid vehicle

Abstract: With breakthroughs in battery technology, plug-in hybrid electric vehicles (PHEVs), jointly powered by an electric drive and an internal combustion engine are becoming a realistic alternative. In a PHEV, the battery is charged by the grid and the electric machine plays the major role in the vehicle drive so that the engine is only required to provide extra torque when accelerating and to drive the generator and vehicle when the battery level is low. This paper discusses a PHEV drive system with only one electric machine which functions as either a motor or generator and a supercapacitor bank for fast charging and discharging during regenerative braking and fast acceleration. The drive system is modeled using PSAT software. Several performance indexes, such as fuel economy, engine efficiency, range and acceleration are used to compare with a traditional vehicle. The PHEV performance is investigated using three typical driving cycles, i.e., an urban driving schedule, an extra-urban driving cycle and a highway fuel economy driving schedule. These are evaluated in detail.

Improved measurement of three-dimensional magnetic properties of SMC material

Abstract: An improved three-dimensional (3-D) magnetic property measurement system, which can indirectly measure the magnetic field strength H vector in a cubic sample of soft magnetic composite (SMC) material by controlling the three components of the magnetic flux density B vectors, has been developed and calibrated. This paper especially describes the improved structure of the sample with H and B sensing coils, and deals with the magnetic compensation problem. The relationship between the B vector and H vector has been measured under alternating and rotating flux conditions by using the 3-D magnetic measuring system, and the core loss features have been analyzed when the B loci are controlled as circles with increasing magnitudes and ellipses evolving from a straight line to circle in three orthogonal planes.

Performance analysis of electric machine drives for plug-in hybrid electric vehicles

Abstract: Much attention has been paid to electric vehicles recently due to environmental concerns. The plug-in hybrid electric vehicle (PHEV) consisting of both electricity storage and gasoline tank is welcome to electric vehicle market. In the PHEV system, the electric machine drive is one of the key issues. The ideal tendency is to use the drive machine over the entire torque/speed range with high starting torque and wide constant power range. The proposed PHEV drive system in this paper has only one electric machine which functions as either a motor or generator at a time and a supercapacitor bank for fast charging and discharging during the regenerative braking and fast acceleration. The drive machine must be designed for frequent start or stop, high acceleration or deceleration, high torque or power density, and good transient performance at all speed range. This paper analyzes the new PHEV resistance power and the driving traits. The drive system is modeled and analyzed by the powertrain system analysis toolkit (PSAT) encoded in Matlab/Simulink toolbox. It compares the different driving performances between the new PHEV and one traditional vehicle in urban dynamometer driving schedule (UDDS).

Study on a wind-solar complementary power inverter

Abstract: This paper studies a wind-solar complementary single-phase sine wave power inverter, including the hardware structure, operating principle, and method to the charging and discharging design. A dual-level three-state intelligent float charging based on PIC single chip control is brought forward for combining the special characteristics of wind-solar energy system. It helps the automatic transfer between charging and discharging and active protection of the battery. Unattended wind-solar complementary power system is achieved. With the help of reasonable calculation and simulation analysis, the final parameters are determined. A prototype of 500W/220V/50Hz single-phase sine wave power inverter has been fabricated. Through the model experiment the output voltage waveforms are found in conformity at both no-load and full-load, and the THD is very low. Therefore, the workability and validity are proved.

An improved series equivalent circuit of a single-sided linear induction motor

Abstract: The derivation of the equivalent circuit for a single-sided linear induction motor (SLIM) is not straightforward. Especially if it includes longitudinal end effects from the cut-open primary magnetic path, transverse edge effects from the differing widths between the primary lamination and secondary sheet, and half filled primary slots. This paper proposes an improved series equivalent circuit for this machine. The longitudinal end effects are estimated using three different impedances representing the normal, forwards and backwards flux density waves in the air-gap. The transverse edge effects accounted for with a correction coefficient K t and an air-gap flux density correction coefficient K b . Using the series circuit, the performance of the SLIM was assessed in a similar manner to a rotating induction machine. A 4 kW SLIM prototype was tested which validated the simulation technique.

Initial rotor position and magnet polarity identification of PM synchronous machines based on numerical simulation

Abstract: In this paper a comprehensive nonlinear model of surface mounted permanent magnet (PM) synchronous machine (SPMSM) is developed considering both the structural and saturation saliencies. After experimentally identifying all the parameters, a nonlinear mathematic model of SPMSM is built, in which the rotor position and stator current are taken as the variables to calculate the inductances. A pulse injection based scheme is proposed to detect the initial rotor position and magnet polarity. A rotor vibration analysis is carried out to finalize the injected signal. The saturation saliency embedded in the nonlinear model is utilized to identify the rotor polarity, which is essential for starting the SPMSM. Simulations are taken for several different rotor initial positions and the result shows that the proposed method is suitable for the SPMSM drive.

Application of Femap in Electromagnetic Field Simulation

Abstract: A finite element analysis program was compiled by the author by means of Femap Application Programming Interface(API), and Femap became useful in electromagnetic filed simulation. In this paper, a model of current-carrying solenoid is built in Femap, the finite element analysis results are presented, and some key codes in the program are given.

Simulation of sensorless drive for surface mounted PM machine based on comprehensive machine model

Abstract: In this paper a comprehensive mathematical model of surface mounted permanent magnet synchronous machine (SPMSM) is developed, in which the nonlinear inductance is expressed a composite function of the rotor position and the stator current. With all the parameters identified experimentally, the new model incorporates both the structural and the saturation saliencies. A sensorless drive system is proposed and simulated based on the comprehensive mathematical model. High frequency carrier signals are injected to the stator windings to detect the rotor axis position and additional DC voltage pulses are added to identify the rotor magnetic polarity based on the saturation effect in the stator core. With the estimated rotor position information, the SPMSM drive system is developed based on the vector control and simulated by using MATLAB/SIMULINK.