Operating modes of single-phase thyristor converter fed dc drives using Phase Angle Control scheme - A monograph

Abstract

Single-phase thyristor full converter and semi been made in the present paper and all the possible modes of converter fed dc drives with phase angle control scheme have operation and the sub-cases therein have been identified and been analysed under all possible modes of operation of continuous the corresponding expressions for the various performance and discontinuous armature current conduction. For each case, factors derived for both thyristor full converter and semi expressions for the various performance quantities have been v presented comprehensively. All the cases have been simulated converter. using power system block set tool box in MATLAB and the III. MODES OF OPERATION simulation results are found to be same as those obtained from the derived expressions. Results obtained on a 220 V, 5 hp separatelyIn the analysis of these converters, we have duty interval(s) excited dc motor operating under all modes of operation, were in which the ac source is connected to the load through a set of also in agreement with simulated / calculated values. thyristors. Depending on the armature circuit inductance, armature current and speed setting there may be a zero current I. NOMENCLATURE interval also. In addition, in the semi converter there could be a free-wheeling interval in which load current flows only E motor back emf, V through the devices and the source current is zero. Based on io : instantaneous armature current ( load current ), A these, the various modes identified are classified in Table 1. is : instantaneous ac supply current, A fundamental component of rms ac supply current, A I : rms ac supply current, A In any mode of operation, considering one-half cycle i.e., Kb back emf constant, volts/rad/sec starting from the instant of firing of one set of devices to the La motor armature circuit inductance, H instant of firing of the other set of devices, the input and output Ra motor armature circuit resistance, Q voltage and current equations of the converter circuits are: Vm maximum value of the ac supply voltage, V VS : instantaneous ac supply voltage, V Duty interval (is = io) vO : instantaneous converter dc output voltage, V VO = vs = Vm Sin o)t (1) V0 average converter dc output voltage, V Raio +La(dio/dt)+E Vs (2) Z motor impedance, Q oc : firing angle, deg Free-wheeling interval (is = 0): P : extinction angle, deg vO= 0 (3) O instant at which the instantaneous supply voltage is Ra io + La (dio / dt) + E = 0 (4) equal to the motor back emf, deg X : angle at which conduction starts, deg Zero current interval (is = = 0) 0) :rotor speed in rad/sec vO = E (5)

A comparison between the algebraic and the reduced order observer approaches for on‐line load torque estimation in a unit power factor rectifier‐DC motor system

“…i a is the armature current and represents the motor shaft angular velocity. Note that the gain values of K e and K t are equal and denoted by K in (1). This is due to energy conservation (power absorbed by the back emf is converted to mechanical power, e.g.…”

“…The thyristor based AC-DC converter bridge has been, for a long time, the most frequently used device in the control of the DC motor speed [1]. However, it exhibits certain disadvantages, such as low input power factor and generation of harmonics, especially in the low-order range.…”

Identification and analysis of operating modes of single-phase semi-converter fed battery charging circuits using extinction angle control scheme — A monograph

“…Extensive simulated and experimental results are also presented in the succeeding sections thereby validating the identification of the various modes of operation and their analysis. A similar analysis by the present authors, made for the 1-phase thyristor converters with PAC scheme and R-L-E load, had been recently presented as a monograph [8]. In the analysis of these converters, there is a duty interval in which the ac source is connected to the load through a set of power devices.…”

Classification and analysis of operating modes of three-phase semi-converters feeding battery charging loads using Phase Angle Control scheme - A monograph

“…Even in advanced text books and papers dealing with such topics, only one case of discontinuous current [5][6][7][8][9] has 978-1-4799-6805-3/15/$31.00 ©2015 IEEE been described. But, the present authors have earlier analysed the operation of single-phase semi-converters with various firing schemes, identified the various current patterns and derived expressions for the various performance quantities such as average dc voltage, total rms and fundamental rms components of ac supply current for each pattern called as a mode [10][11][12]. Such a rigorous analysis is now made for the three-phase semi-converters, activated with Phase Angle Control scheme (PAC) and supplying batteries.…”