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A novel fuzzy sliding-mode structure has been proposed for the model reference adaptive system(MRAS) based sensorless control of an induction motor in this paper. The design includes a hybrid MRAS from measured stator terminal voltages and currents. The estimated speed is used as feedback in an indirect vector control system achieving the speed control without using shaft mounted transducers. Fuzzy sliding-mode structure includes two nonlinear controllers, one of which is sliding mode type and the other is PI-fuzzy logic based controller, the latter define a new control structure. Both controllers are combined by means of an expert system based on Takagi-Sugeno fuzzy reasoning. The sliding mode controller acts in the steady state. The new structure has two advantages: sliding-mode controller increasing system stability and PI-like fuzzy logic based controller reducing the chattering in permanent state. The scheme has been implemented and experimentally validated.

A novel fuzzy sliding-mode structure have been proposed for the model reference adaptive system(MRAS) based sensor-less control of an induction motor in this paper. The design includes a hybrid MRAS from measured stator terminal voltages and currents. The estimated speed is used as feedback in an indirect vector control system achieving the speed control without the use of shaft mounted transducers. Fuzzy Sliding-Mode Structure include two nonlinear controllers, one of sliding mode type and the other PI-fuzzy logic based, define a new control structure. Both controllers are combined by means of an expert system based on Takagi-Sugeno fuzzy reasoning. The sliding mode controller acts in the steady state. The new structure embodies the advantages that both nonlinear controllers offer sliding mode controllers increasing system stability limits and PI-like fuzzy logic based controllers reducing the chattering in permanent state. The scheme has been implemented and experimentally validated.

A novel scheme of low power communication power supply with high power factor and soft-switching is presented, a power factor corrector and dc/dc converter of passive lossless soft-switching is based on a ML4803 IC control. DC/DC converter introduces a novel two-transistor forward soft-switching technique, which realizes zero-voltage turn-on and turn-off, with no additional switches. a communication power supply module is developed in this paper. It has the characteristics of rapid dynamic response, high power factor, high efficiency and small bulk ect.

A novel hybrid clamped dual-PWM three-level converter topology is proposed for induction motor drives in this paper. The switching states of hybrid clamp three-level converters increase to sixty-four from twenty-seven switching states of diode clamp three-level converters. In order to realize optimization of its redundant voltage space vectors by detecting voltage of clamp capacitor and difference of capacitor voltage in DC side, Generating an optimized switching pattern, The hybrid clamped three-level converter increases the voltage levels number, reducing the harmonics associated to the commutation frequency and limiting the dv/dt by all the switches. It can quickly balance the DC voltage, Realized system of 4-Quardant Running. the control circuit and main circuit was designed with DSP and CPLD, experimentation results proved it is very effective and practicability.

A novel algorithm for the naturally sampled SVPWM in overmodulation region is proposed in this paper, the comparison between naturally sampled SVPWM and conventional SVPWM in overmodulation region is carried out. It was proved that naturally sampled SVPWM could be used not only in under modulation but also in overmodulation region by the results of analysis and simulation. The work was done by this paper shows a promising use of the naturally sampled SVPWM. The obviously advantage is that it could be implemented by using DSP with only simplified computation and short time of on line calculation, or just by using analog circuits without the help of microprocessor at all. All the work did by this paper provide a platform for the implementation of naturally sampled SVPWM operating in under modulation and over modulation region.