A Sliding Mode Control (SMC) with integral surface is employed to control the speed of Three-Phase Induction Motor in this paper. The strategy used is a modified field oriented control to control the IM drive system. The SMC is used to calculate the frequency required for generating three phase voltage of Space vVector Pulse Width Modulation (SVPWM) invertor. When the SMC is used with current controller, the quadratic component of stator current is estimated by the controller. Instead of using current controller, this paper proposed estimating the frequency of stator voltage whereas the slip speed is representing a function of the quadratic current. The simulation results of using the SMC showed that a good dynamic response can be obtained under load disturbances as compared with the classical PI controller; the complete mathematical model of the system is described and simulated in MATLAB/SIMULINK.
In this thesis,surface integrals and the relationship between characteristics of the second class and second class double integral surface integrals, analyzes the application of the law of symmetry integral calculation, even if the integration region derived symmetric integrand is an odd function integral value characteristic is not necessarily zero. And pointed out that the feasibility of the method is definitely second class surface integrals.
The performance of transonic compressors can be characterized aerodynamically and aeroacoustically. In this paper, the DLR SRV2 compressor without vaned diffusers and its redesigned version are studied. The redesign strategy (Zangeneh et al. 2011 [1]) utilized the 3D inverse design and CFD analysis. Both compressors were analyzed in ANSYS CFX 11, and the computational results show that the predicted pressure-ratio and efficiency of the original compressor have good agreement with experimental results. The simulations have also revealed that the redesigned one is superior at both design and off-design points at different rotating speeds.
This work applies a convective FW-H method to further investigate the noise radiation from these two compressors. As the blade tip speed is supersonic, the permeable integral surface scheme must be adopted. The flow quantities needed as the inputs to the FW-H solver were extracted from the CFD solutions. The numerical predictions of the noise SPLs at blade passing frequency and its harmonics match the experimental measurements reasonably well. It is found that the original compressor has significant variations of SPLs as the operating mass flow rate changes whereas the redesigned one has much slighter variations. At peak efficiency the redesigned compressor has a lower noise level.
This study provides insights for the optimal design of a transonic compressor when good aerodynamic and aeroacoustic performance are both required.
Speed Controller of Three Phase Induction Motor Using Sliding Mode Controller