According to the reduced order model of induction motor,a model reference adaptive speed identification algorithm was obtained from the equations of motor stator voltages and currents. An improved MRAS model was built with variable parameters. The detailed simulation researches were tested on the speed-sensorless vector control.

For above purpose, we must synchronously and constantly acquire several signals, such as stator voltages, stator currents, rotor speed of asynchronous motor and so on, and synchronously save, dynamically display, fully analyze and process the acquired signals.

The paper describes a model -- reference adaptive system (MRAS) for the identification of induction motor speed ho measured motor stator voltages and currents.

According to the reduced order model of induction motor, a model reference adaptive speed identification algorithm is obtained from measured motor stator voltages and currents.

Just using the stator currents, stator voltages, and velocity, the method proposed in the paper makes real time identification of induction motor parameters based on the least squares identification algorithm. The method doesn't use the rotor flux signal, avoiding the coupling between the rotor flux observation and the parameter identification.

The paper describes a model reference adaptive system for the identification of induction motor speed from measured motor stator voltages and currents.

Base on the stator currents and stator voltages,take the rotor speed as a state variable of the system,this paper presents a Extended Kalman Filter to estimate the rotor speed.

Based on the stator currents and stator voltages,taking the rotor speed as a state variable of the system,to estimate the rotor speed,the Extended Kalman Filter to be optimized by choosing the proper initial value,the experiment results of estimation speed value with high veracity,the system with a strong robustness to be insensitive to the machine parameter variations were presented in this paper.

By introducing directly triphase parameters and considering stator current as control variable, the state equations of induction motor have been derived in this paper. Since the actual phase parameters are introduced directly, this kind of state equations is favourable for applying it in association with the current-controlled type inverter. Besides the derivation of such fundamental equations expressing the transient process of current-controlled . induction motor, the steady state initial values of the...

By introducing directly triphase parameters and considering stator current as control variable, the state equations of induction motor have been derived in this paper. Since the actual phase parameters are introduced directly, this kind of state equations is favourable for applying it in association with the current-controlled type inverter. Besides the derivation of such fundamental equations expressing the transient process of current-controlled . induction motor, the steady state initial values of the transformed rotor flux links ψ2A and ψ2c are also discussed.Summary. Triphase physical quantities of rotor can be transformed into those in stator system by the following matrix:is applicable to the biphase transformation so as to express the fundamental equations in terms of actual values of stator. To obtain the steady state in simulation, initial values of flux links ψ2A and ψ2B can be assigned ar-bitralily, e.g. the null initial value (cf. Fig. 2) , but it is time-consuming. Two possible methods of estimating the initial values of flux links are thus suggested based on assumptions that the resultant flux link field of rotor is rotation field or the stator current is of sinusoid. Initial values of ψ2A and ψ2B can be assigned in either way.Fig.1 A 3-phase induction motor fed by current-controlled inverter Fig.2 Time responses ψ2A(t) and ψ2B(t) as ψ2A0 = ψ2B0 =0Fig.3 Time responses ψ2A(t) and ψ2B(t) as ψ2A0= -0.0425887 (a) and0.2 (6)Fig.4 Two cases of assigning initial values to stator current Fig.5 Steady-state equivalent circuit: (a) in form of complex vector,(b) correspondent to stator voltage equation.

This paper features a comprehensive survey of all the plans, which are applicable to crane hoists, of the speed control of wound motor rotor thyristor. With the development of power semi-conductors, these plans will find their wide application and perfection. The paper believes that the speed control by the rotor thyristor is simpler than and superior to that by a.c. stator voltage regulation. In order to solve large overloading required by low speed and long operation, the paper analyses the constitution...

This paper features a comprehensive survey of all the plans, which are applicable to crane hoists, of the speed control of wound motor rotor thyristor. With the development of power semi-conductors, these plans will find their wide application and perfection. The paper believes that the speed control by the rotor thyristor is simpler than and superior to that by a.c. stator voltage regulation. In order to solve large overloading required by low speed and long operation, the paper analyses the constitution and performance of the speed control of a.c. motors both by pulse modulation and resistance regulation. As a result, this paper provides the cases in which all the plans can be applied.

This paper introduces an approach to calculate startting damper cuurent and temperature distributions in salient pol synchronous motors. D-Q equivalent circuit analysis and finite element solution of electromagnetic field are combined in this method. The comparison of calculated damper temperature rises with tested results on a 2200KW synchronous motor shows that the presented computation method has a good engineering accuracy. The influences of stator voltage and attached resistance to the field winding...

This paper introduces an approach to calculate startting damper cuurent and temperature distributions in salient pol synchronous motors. D-Q equivalent circuit analysis and finite element solution of electromagnetic field are combined in this method. The comparison of calculated damper temperature rises with tested results on a 2200KW synchronous motor shows that the presented computation method has a good engineering accuracy. The influences of stator voltage and attached resistance to the field winding on the startting damper cuurents and temperature rises are also discussed in the paper.