Applied Mechanics and Materials Vols. 672-674

Abstract: A design scheme of the control system was put forward to solve the performance control problems of the motor in this paper, combining with the composition and working principle of permanent magnet brushless DC motor. Hardware circuit of the control system was designed with digital signal processor (DSP) as the core, which mainly consists of the power drive circuit, the motor position, speed detection circuit and winding current detection circuit. Software flow of the control system was also designed, and software program debugging was achieved on CCS3.3 DSP integrated development environment, and the rationality of the software program was validated.

Abstract: An efficiency optimization model for induction motors with speed-sensorless control is presented in this paper. An mathematical loss model with stator iron loss in DTC(Direct Torque Control) system is used to calculate the motors loss, the loss efficiency and the optimal flux. Additionally, the efficiency optimization control strategy combined with the speed-sensorless model is used to rebuild the simulation modeling. The simulation results with the proposed control strategy show superior effects compared to the traditional control methods. The optimal control strategy can be achieved to improve the motor efficiency.

Abstract: Traditional square current driving method has deficiencies in muting and efficiency when controlling the brushless DC motor. This paper presents a method of space vector pulse width modulation for BLDCM, which is in five-segment type. A mathematical model of BLDCM, which is in d-q coordinate system, was established. Then, the experimental platform was constructed with the STM32F103 for BLDCM of electric vehicle. And the experiment results verify the properties of little torque ripple, smooth operation and low switching losses. Besides, the system dynamic and static performance is greatly improved, and has strong robustness. The method proposed overcomes the shortcomings of square current driving method in control efficiency and motor noise.

Abstract: In this paper, a new technique for diagnosing multiple open switch fault in three phase voltage inverter feeding induction motor is presented. It is based on the so-called the Lissajous curve of an auxiliary winding voltage Park components. For this purpose, expressions of the inserted winding voltage and its Park components are presented. Simulation results curried out for non defected and defected inverter show the effectiveness of the proposed method.

Abstract: This template illustrates the control system of permanent magnet synchronous motor(PMSM) which uses field oriented vector control(field oriented vector control). PMSM is a complex, strong coupling and nonlinear system. And field oriented vector control could provide good performance as well as the PI controller setted with well parameter matching. Whereas limited by the number of voltage vector, the other control method of PMSM, direct torque control, could not satisfy accurate control when the machine running with a low speed. So modulation of the whole system is built here to realize closed-loop field oriented vector control control by keeping id=0 , and the machine model and the transformation among different coordinate system are discussed. The system is verified effective and feasible.

Abstract: When synchronous generator operates steadily, the slip remains essentially unchanged, and the traditional first-order mathematical model can be used to analyze its operating procedures. But when it occurs asynchronously failure, the traditional model of a first-order mathematical operation can no longer be used accurately to analyze its state. This paper establishes time-varying parameter model considering the rotor eddy based on mutual leakage field winding and straight shaft damper windings resistance, and uses simulation analysis and comparison of experimental verification methods to verify the correctness of the model for synchronous generator asynchronous operation, which provides a theoretical basis.

Abstract: In this paper, a new technique for diagnosing faults in three phase voltage inverter feeding induction motor is presented. It is based on the so-called the voltage spectrum of an auxiliary winding. For this purpose, expression of the inserted winding voltage is presented. After that, discrete Fourier transform analyzer is required for converting the voltage signal from the time domain to the frequency domain. Simulation results curried out for non defected and defected inverter show the effectiveness of the proposed method.

Abstract: With the 2407 and VC33 double DSP system as the foundation of hardware, the basic idea is using a modified voltage model, implementation, and equivalent amplitude and phase characteristic of integral operation. Motor steady-state operation, the rotor counter electromotive force signal is a sine wave. And an ideal sinusoidal signal frequency for omega after integral link operation, output phase lag, amplitude to times. Observations can be found from the experiment of flux linkage and rotor counter electromotive force signal on the output phase and phase is obtained by pure integral part still have a little deviation, it will need a further study on the compensation link, how to make the compensation phase completely equivalent to the integral effect. From the point of the results of the experiment of 5 Hz low speed estimation error, verify the theory in this paper. One step closer to the test is more slow speed estimation.

Abstract: The different penetration capacity of various distributed generation (DG) in distribution network has important effect on planning and dispatching scientifically. The dynamic model of a small synchronous generator is established in this paper, and we figure out the maximum acceptable power of distributed generation for each node in distribution network considering reliability of protection electromagnetic transient simulation method, and the limiting factors are also analyzed in it. Finally, some methods are proposed to improve maximum penetration capacity, so it can provide reference for farther research of maximum penetration capacity in next stage.

Abstract: The change of wind power generation, photovoltaic power generation and power load reflects the regularity and randomness at the same time, which leads to a casual fluctuation of power flow in urban power grid with multiple generators. The static and dynamic probabilistic power flow model are compared and analyzed in this paper, the dynamic probabilistic model is adopted for simulating the characteristics of power flow in urban power grid with multiple DGs. The results show that the power flow of urban power grid changes not only regularly but also randomly. These two characteristics of power flow should be considered for power grid dispatching and control.