G. K. Dubey

A General Method of Analysis of Chopper Fed D.C. Separately Excited Motor

A generalised method of analysis of chopper fed d.c. separately excited motor has been presented taking into account the effect of source inductance, chopper commuitation interval, discontinuous conduction and the effect of armature reaction of the motor. The experimental performance agrees very vell with the predicted performance.

DYNAMIC MODEL OF CHOPPER FED DC SEPARATELY EXCITED MOTOR

ABSTRACT This paper describes the transient response of a chopper fed dc separately excited motor using time ratio control. An approximate second order model for predicting the transient behaviour of the motor is developed using perturbation technique. The transient response for small and sudden variations of duty interval and load torque is deduced during discontinuous and continuous current mode operations. The effect of external inductance on the performance of motor in the armature circuit has also been investigated. The results are compared with those obtained from a digital computer by numerically solving the simultaneous differential equations valid for different intervals of chopper cycle and also with the first order model. It is shown that the second order model is more accurate than the first order model and much simpler and efficient than the numerical approach. The theoretical results obtained are also verified with an experimental set up. Experimental results closely agree with theoretical p...

Performance and Analysis of Chopper Fed D. C. Series Motor with Magnetic Saturation, Armature Reaction and Eddy Current Effect

An analysis has been carried out to predict the steady state performances of d.c. series motors controlled by chopper taking into account, the saturation of the magnetic circuit, effect of eddy currents in the field cores, and the armature reaction. The effect of chopper commutation pulse has also been taken into account. It has been shown, that, for the calculation of armature current ripple, incremental inductances have to be used and it has been demonstrated that, eddy currents influence the current ripple. The analytical results agree well with the experimental results.

PERFORMANCE AND ANALYSIS OF CHOPPER FED D.C. SEPARATELY EXCITED MOTOR UNDER REGENERATIVE BRAKING

Abstract A method is presented here to analyse the performance of a separately excited d.c. motor under regenerative braking mode and provides a technique to select the necessary inductance to reduce the ripple in the armature current as well as to eliminate the discontinuous conduction of the armature current and to optimize the regenerative power. The effect of armature reaction and also that of chopper commutation interval have been taken into account. The calculated performance agrees very closely with the experimental results.

TRANSIENT ANALYSIS OF CONVERTER-CONTROLLED DC SEPARATELY EXCITED MOTOR

ABSTRACT Three methods of transient analysis of a de separately excited motor controlled by a phase-controlled converter have been derived. These methods are compared with regard to accuracy, computation time and usefulness.

GENERALIZED METHOD OF ANALYSIS OF CHOPPER-FED DC SEPARATELY EXCITED MOTOR UNDER REGENERATIVE BRAKING

ABSTRACT A generalised method of analysis for predicting performance of d.c. separately excited motor under regenerative braking controlled by load current commutated chopper, has been presented. It has been shown that the source inductance, in the absence of filter capacitor at the source terminals, considerably influences the chopper commutation and machine performance. It has experimentally been shown that the use of a suitable filter capacitance at the source terminal neutralizes the effect of source inductance. Calculated characteristics agree well with the experimental results

A CHOPPER FOR CONTROL OF DC TRACTION MOTOR

Abstract The paper describes a new chopper circuit capable of wide range of output voltage control and high frequency operation. The chopper has been analysed taking line inductance into account and expressions have been presented for the calculation of commutation circuit component parameters. A method has been presented for the calculation of motor performance and ripple in armature current. It takes into account the non-linearity of motor magnetic circuit and the effect of commutation pulse on motor performance.

Comparative performance of two quadrant choppers capable of giving positive current and voltage in either direction

ABSTRACT Three possible control approaches for a two quadrant chopper, capable of providing positive current and voltage in either direction from a fixed d.c. input, are compared in this paper. The comparative study has been carried out for two types of loads -(a) Highly inductive load (ripple free current) and (b) Motor load The performance at the input as well as the load terminals is analysed and the results are presented in terms of normalised values. The boundaries between continuous and discontinuous conduction are also drawn to facilitate an estimation of filter inductance.

ANALYSIS OF CONVERTER CONTROLLED DC SERIES MOTOR. I. STEADY STATE ANALYSIS

ABSTRACT The steady state and transient analysis methods of converter-fed dc series motor reported so far do not take into account the nonlinearity of the magnetic circuit. Furthermore, for transient analysis discontinuous conduction has been neglected and only first order model has been reported though series motor is essentially a second order system. In the present paper steady-state and transient analysis methods have been presented for fully-controlled and half-controlled converter-fed dc series motor taking the nonlinearity and discontinuous conduction into account. The paper has been divided into two parts. Part I presents various approximations for the nonlinearity of the magnetic cir-circuit methods of calculating steady state performance and a method of calculating a suitable value of filter inductance. Theoretical deductions have been verified experimentally Part II of the paper presents the methods of transient analysis

PERFORMANCE AND ANALYSIS OF CHOPPER FED D.C. SERIES MOTOR UNDER REGENERATIVE BRAKING

ABSTRACT The paper presents a method of analysis and performance of chopper fed dc series motor under regenerative braking. The method of analysis takes into account the nonlinearity of the magnetic circuit, armature reaction, effect of commutation pulse and source inductance. Equations have been derived for the calculation of (a) machine speed-torque characteristics (b) regenerative power and efficiency of regeneration, and (c) current ripple and filter inductance value. The method also shows the prediction of stability at low speeds and conditions for failure of regeneration. The effects of chopper operating frequency, source inductance, commutation capacitor and input-filter capacitor on regenerative power and efficiency of regeneration, and stability of braking have been described. Theoretical deductions have been verified experimentally