Shanghai STEP Electrical Corporation

Shanghai, China

Shanghai STEP Electrical Corporation

Shanghai, China
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Wang F.,Tongji University | Wang F.,Shanghai Step Electrical Corporation | Ma X.,Tongji University | Chen D.,Tongji University
Gongneng Cailiao/Journal of Functional Materials | Year: 2017

Compared with the semi-infinite structure, the slab should consider the multiple scattering of thermal waves about the upper and lower bounds. In this paper, based on the non-Fourier heat conduction equation, the temperature distributions at the surface of functionally graded slab containing a cylindrical defect are investigated by using image method and wave function expansion method. According to the model of thermal wave, a general solution of scattered fields of thermal waves is obtained. The thermal waves are excited on the surface of functionally graded slab by periodically modulated laser. The cylindrical defect is taken as a cavity under thermal insulation condition. The boundary condition of the surface is adiabatic. Boundary conditions of the upper and lower of the functionally graded slab are equal to the environment temperature. The amplitude of the changes in temperature at the frontal surface in the cylindrical defect due to different physical and geometrical parameters is analyzed and presented graphically using the analytical method, and the impact of non-uniform parameters of functionally graded slab on surface temperature is focused on. The results of this paper are expected to provide calculation methods and references data for infrared thermal wave evaluation of functionally graded slab. © 2017, Chongqing Functional Materials Periodical Press Co. Ltd. All right reserved.

Xu L.,University of Jinan | Zhou M.,Shanghai STEP Electrical Corporation | Zhao L.,University of Jinan | Huang S.,University of Jinan | And 2 more authors.
Gongneng Cailiao/Journal of Functional Materials | Year: 2016

The surfactant and plating technology played an important role in the process of electroless nickel plating. The experiment based on PZT-4 ceramic plating in the alkaline solution to obtain Ni-P alloy coating. The influence of OP emulsifier on PZT-4 ceramic surface chemical nickel plating was discussed. Using plating speed, coating corrosion resistance, surface morphology, element composition, electrical conductivity test, and the phase structure of plating technology to study the effects of temperature, acidity and OP emulsifier concentration on the properties of the coating. Results show that when the OP emulsifier concentration in plating solution is 15-25 mg/L, the coating has good performance, the best plating process condition range as follows: 40-45℃ as the plating temperature range, 8.5-9.0 as the pH value range. © 2016, Chongqing Functional Materials Periodical Press Co. Ltd. All right reserved.

Wang G.,Harbin Institute of Technology | Wang Y.,Harbin Institute of Technology | Qi J.,Harbin Institute of Technology | Ni R.,Harbin Institute of Technology | And 2 more authors.
9th International Conference on Power Electronics - ECCE Asia: "Green World with Power Electronics", ICPE 2015-ECCE Asia | Year: 2015

Offline inductance identification of permanent magnet synchronous motor (PMSM) is essential for self-tuning of closed-loop controller and position observer in sensorless vector controlled drives. This paper proposes an enhanced offline identification method fulfilled at standstill with adaptive inverter nonlinearity compensation for general-purpose drive applications. The d-q axis inductances can be obtained at standstill by using a voltage-source-inverter fed drive. Influences of inverter nonlinearities on direct and quadrature inductance identifications exploiting high frequency (HF) voltage injection at different rotor positions are analyzed. Then an adaptive inverter nonlinearity compensation strategy employing a simple self-learning of compensation coefficients is proposed to enhance the accuracy of inductance identification. The feasibility of the proposed adaptive offline inductance identification method is validated on a 22kW interior PMSM. © 2015 Korean Institute of Power Electronics.

Liu H.,Harbin Institute of Technology | Zhu H.,Harbin Institute of Technology | Wu H.,Harbin Institute of Technology | Wang W.,Harbin Institute of Technology | And 2 more authors.
Zhongguo Dianji Gongcheng Xuebao/Proceedings of the Chinese Society of Electrical Engineering | Year: 2015

Droop control is used in PV inverter system, which can achieve seamless switching between grid-connected mode and islanded mode. According to the characteristic impedance of low-voltage electrical wires, a novel voltage-controlled method for grid-connected PV inverter is proposed in this paper. By adding a power loop and a DC-link voltage loop to droop control, the power of inverter cannot be influenced by grid fluctuation, the power control ability of PV inverter is strengthened, PV inverter can output maximum active power into grid and the dc-bus voltage is stable. The validity of the proposed method is verified by experimental results. © 2015 Chinese Society for Electrical Engineering.

Wang G.,Harbin Institute of Technology | Yang R.,Harbin Institute of Technology | Zhang J.,Harbin Institute of Technology | Yu Y.,Harbin Institute of Technology | And 3 more authors.
Diangong Jishu Xuebao/Transactions of China Electrotechnical Society | Year: 2012

Field-oriented controlled induction motor drives may be detuned due to rotor time constant variation. A rotor time constant estimation method based on model reference adaptive system (MRAS) with reactive power model is presented. Convergence of the estimator is proved using the Popov's super-stability theory. Since dead-time effect of inverter may induce reconstruction error of phase voltage and waveform distortion of stator current. A dead-time compensation strategy is presented to improve accuracy of model calculation. The stator current vector angle is obtained in synchronous rotating scheme. Then sensitivity of motor parameters to the model is analyzed. The feasibility of the proposed estimation is verified by experimental results of field-oriented vector controlled 11kW induction motor drive.

Chen W.,Shanghai STEP Electrical Corporation | Jin X.,Shanghai STEP Electrical Corporation | Cai L.,Shanghai STEP Electrical Corporation | Xu D.,Harbin Institute of Technology
Zhongguo Dianji Gongcheng Xuebao/Proceedings of the Chinese Society of Electrical Engineering | Year: 2013

Induction motor V/f open-loop drive system suffer sustained oscillation problem in light load condition. Many methods have been presented to suppress the oscillation. However, a generally accepted theory about the cause of this oscillation problem is not revealed. This paper mainly focuses on the research of the cause of the sustained oscillation problem of IM V/f drive system. Through simulation modeling, the system instability is analyzed in detail based on the simulation results. Then by theoretical derivation, the reasons that result in the instability under light load condition are studied, and the influences on system stability of various parameters are also analyzed. The conclusions derived in this article are consistent with the actual phenomenon very well. In addition, the derived conclusions can be used to predict the oscillation of the IM V/F open-loop control system. © 2014 Chin. Soc. for Elec. Eng.

Du J.,Dalian Maritime University | Zhao J.,Shanghai STEP Electrical Corporation | Wu Y.,Dalian Maritime University | Li G.,Dalian Maritime University
Chinese Control Conference, CCC | Year: 2013

A new adaptive robust approach is proposed for the nonlinear course control problem of ships with parameter uncertainties, completely unknown control gain and unknown bounded environmental disturbances based on backstepping. Nussbaum function is used to deal with the unknown sign of uncertain control gain and avoid the possible controller singularity problem. Dynamic surface control is combined with backstepping technique to overcome the problem of 'explosion of terms'. By means of Lyapunov function and the lemma of Nussbaum function, it is proved theoretically that the designed adaptive nonlinear controller can guarantee the global uniform ultimate boundedness of all signals of the resulting ship course tracking control system and make the course tracking error arbitrarily small by an appropriate choice of the design parameters. The simulations on the mathematical model of the ship are carried out. The simulation results demonstrate the effectiveness of the proposed control scheme. © 2013 TCCT, CAA.

Ji S.,Shandong Jianzhu University | Zhang C.,Shandong University | Hu T.,Shandong University | Wang K.,Shanghai STEP Electrical Corporation
International Journal of Computers, Communications and Control | Year: 2016

Ethernet for Manufacture Automation Control (EtherMAC) is a new kind of real-time Ethernet used in motion control systems. It adopts a line topology with a standard industrial computer based master node and field-programmable-gate-array based slave nodes. EtherMAC employs one slave node to manage cycle communication and clock synchronization, so the real-time demand for its master node can be greatly reduced and dedicated hardware is no longer mandatory. Its distributed clock compensation mechanism can get synchronization accuracy in nanosecond order. The advantages of industrial computer and field programmable-gate-array are combined with EtherMAC, so that high control performance can be achieved. © 2006-2015 by CCC Publications.

Li W.,Tongji University | Chen W.,Shanghai STEP Electrical Corporation
Zhongguo Dianji Gongcheng Xuebao/Proceedings of the Chinese Society of Electrical Engineering | Year: 2014

In order to eliminate the arc in 5 ms, the Thomson coil actuator is adopted as the grounding switch of the arc eliminator. An equivalent circuit method was developed to analyze the dynamic characteristics of the grounding switch, which reduces the calculation time from several hours to several minutes, comparing with the finite element method (FEM). To get a quick response of the arc eliminator, optimal design has been done by using a combination calculation method. At the same time the parameters affecting the performance of the arc eliminator are also analyzed in detail. Both combination calculation and parametric analysis of the arc eliminator are executed based on the adaptive equivalent circuit method. © 2014 Chin. Soc. for Elec. Eng.

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