Showing papers in "IEEE Transactions on Industrial Electronics and Control Instrumentation in 1976"
TL;DR: In this paper, a converter philosophy for controlled transfer and transformation of electric energy through internal series resonant circuits at high internal power frequencies in excess of 10 kHz is presented, which is suited for construction of failsafe and highly efficient, low cost, submegawatt, single module converters with currently available components.
Abstract: Presented is a converter philosophy for controlled transfer and transformation of electric energy through internal series resonant circuits at high internal power frequencies in excess of 10 kHz. Control of the continuously oscillating high Q series resonant circuit is attained by adjustment of the phase angle ? r between the exciting voltage and the resonant current. Only a very small fraction of the energy transferred to the load is absorbed by the resonant circuits to replace the power dissipated therein. Moderate and unconditionally predictable voltage and current stresses on components result from definite control of static and dynamic behavior of the system. This system is suited for construction of failsafe and highly efficient, low cost, submegawatt, single module converters with currently available components.
195 citations
TL;DR: In this article, the relationship between attenuation and phase shift of electromagnetic waves passing through a wet substance and weights of water and dry substances have been used for calculation of the real value of moisture content of the substance.
Abstract: Relations between attenuation and phase shift of electromagnetic waves passing through a wet substance and weights of water and dry substance have been used for calculation of the real value of moisture content of the substance. The result appears to be independent of the denity of the substance, its layer thickness and flatness of its surface. Measuring set-up for continuous measurement requires some extensions when compared with a single-parameter measuring set-up, but it is still supplied by a oscillator working at one constant frequency and it consists of only one sensor.
119 citations
TL;DR: In this article, a closed-loop control system to reduce the reactive power required by electronic converters is proposed, where the instantaneous reactive power which consists of both displacement of fundamental current and harmonic distortion current is measured and compensated by a reactive power source connected parallel between the power lines and the converter.
Abstract: A closed-loop control system to reduce the reactive power required by electronic converters is proposed. The instantaneous reactive power which consists of both displacement of fundamental current and harmonic distortion current is measured and compensated by a reactive power source connected parallel between the power lines and the converter. A combination of a dc choke and a forced-commutated inverter is used for the reactive power source.
65 citations
TL;DR: In this paper, a dc converter for sub-megawatt applications is described and illustrated with the characteristics of a small scale 10 kW model, which is characterized by the behavior of a true current source with inherent short circuit capability of its output terminals.
Abstract: A type of industrial size dc converter for submegawatt applications is described and illustrated with the characteristics of a small scale 10 kW model. High conversion efficiency near 97 percent is maintained at full power and with an internal frequency of operation near 10 kHz. The system is characterized by the behavior of a true current source with inherent short circuit capability of its output terminals. All power is processed via a firmly controlled high Q series resonant circuit. Feasibility of power densities in excess of 1 kW/kg component weight is demonstrated. This high power density reflects itself in low quantities of material needed for construction of these systems. Operation of the dc converter as part of a rectifier-filter converter system, powered from a three-phase supply line is described. Test data demonstrate a high power factor PF?0.95 for all conditions of converter loading. Data obtained from a thyristor bridge-filter system are presented and subjected to comparative analysis.
47 citations
TL;DR: In this article, an optical transducer is described which provides a pulse rate and the pulse period is measured and the division of time is achieved by either a general purpose or a special purpose processor.
Abstract: A new approach to digital measurements of angular velocity for control applications is discussed. An optical transducer is described which provides a pulse rate. The pulse period is measured and the division of time is achieved by either a general purpose or a special purpose processor. Since sampling intervals are small, measurements are available in digital form almost immediately. Other advantages include the capability to measure transient angular velocity characteristics and the accurate measurement of angular velocity near zero. With modifications the system can be transformed into an accelerometer.
40 citations
TL;DR: In this article, a nonlinear control system is approximated about desired equilibrium points in state space as linear control systems using a Taylor series expansion, and the techniques of the linear regulator problem are then used to calculate the linear state variable feedback gains needed to keep the system at the desired equilibrium point.
Abstract: Using a Taylor series expansion, nonlinear control systems are approximated about desired equilibrium points in state space as linear control systems. The techniques of the linear regulator problem are then used to calculate the linear state variable feedback gains needed to keep the system at the desired equilibrium point. Liapunov's second method is the basis for determining stable regions of operation about the equilibrium points. When driving the system from one equilibrium point to another, the piecewise linearization method is also used but with intermediate equilibrium points successively utilized. Enough equilibrium points are used so that the system is stable throughout the region of interest. Thus, a nonlinear system is controlled using linear state variable feedback. A small digital computer is required to implement this strategy.
32 citations
TL;DR: In this article, a motor speed controller is presented using digital techniques to measure, compare, and correct motor speed, and it is shown how a direct extension of this design concept can easily bring steady-state error to well below 0.1% of maximum speed.
Abstract: A motor speed controller is presented using digital techniques to measure, compare, and correct motor speed. In the prototype model, the range of speed control is approximately 200 rpm to 3000 rpm. The digital approach eliminates measurement nonlinearity and makes the speed setting exactly reproducible. The prototype's steady-state error is less that 0.2% of maximum speed, and it is shown how a direct extension of this design concept can easily bring steady-state error to well below 0.1% of maximum speed.
28 citations
TL;DR: In this article, the use of pulse width-modulated amplifiers for dc servo systems, in order to reduce the power dissipation in the output stage is proposed, where the amplifier transistors can be switched in different sequences, and the amplifier will operate accordingly in three possible modes, namely the bipolar, the unipolar and the limited unipolar modes.
Abstract: The use of pulse width-modulated amplifiers for dc servo systems, in order to reduce the power dissipation in the output stage is proposed. The amplifier transistors can be switched in different sequences, and the amplifier will operate accordingly in three possible modes, namely the bipolar, the unipolar, and the limited unipolar modes. The principle of operation and the mathematical model for each case are described along with the special features of this amplifier which include the power dissipation in the motor and the selection of the switching frequency.
17 citations
TL;DR: The main problem in the analysis of chopper-fed dc series is due to the interdependence of armature induced voltage and the armature current and the fact that the relation between the two is nonlinear as mentioned in this paper.
Abstract: The main problem in the analysis of chopper-fed dc series is due to the interdependence of armature induced voltage and the armature current and the fact that the relation between the two is nonlinear. The different aspects of analysis such as performance equations, methods of their solution, and the representation of nonlinear magnetization characteristics of the dc series motor are described. The calculated performance has been compared with the measured results.
16 citations
TL;DR: In this paper, a practical implementation of the use of phase-locked loop for the ontrol of a dc servomotor is described, and the results show that it is possible to get good performance while using cheap commercially available components, including integrated-circuit chips.
Abstract: A practical implementation is described of the use of phase-locked loop for the ontrol of a dc servomotor. Test results show that it is possible to get good performance while using cheap commercially available components, including integrated-circuit chips. Complete details of the design are given.
16 citations
TL;DR: In this article, the mixed method of Shieh and Wei is extended to the z domain to simplify z domain-transfer function matrices with various dimensions, and the reduced model is always stable and the dominant performance of the original system is retained.
Abstract: The mixed method of Shieh and Wei which utilizes the dominant-eigenvalue concept and the continued fraction approach is extended to the z domain to simplify z domain-transfer-function matrices with various dimensions. The reduced model is always stable and the dominant performance of the original system is retained.
TL;DR: In this article, two control schemes are proposed and investigated for solid-state dc series motor drive, and performance characteristics such as torque speed, input harmonic content, power factor variation, and peak motor current are obtained for both control schemes.
Abstract: In this paper, two control schemes are proposed and investigated for solid-state dc series motor drive. Performance characteristics such as torque speed, input harmonic content, power factor variation, and peak motor current are obtained for both control schemes and compared with the commonly used phase-angle control scheme under identical operating conditions. The input power factor is always lagging in the phase and symmetrical angle control schemes, while it is leading in extinction angle control scheme over a wide range of speed and power. Each control scheme appears to have certain merits over the other schemes. Experimental results verify the basic principles of operation and demonstrate the feasibility of these control schemes.
TL;DR: In this article, the effect of forced-commutation on the ac phase controller with a series resistance-inductance load has been investigated, and it has been shown that the total circuit power factor can exceed that of the load to sinusoidal current, with selected firing angles.
Abstract: The effect of forced-commutation on the ac phase controller with a series resistance-inductance load has been investigated. It has been shown that the total circuit power factor can exceed that of the load to sinusoidal current, with selected firing angles. Two modes of switching are introduced in which one maintains the fundamental power factor to near unity despite the load being largely inductive. In the second the fundamental power factor is kept to its most leading value and a relative improvement in distortion factor is achieved.
TL;DR: In this paper, a variable frequency, variable amplitude three-phase low frequency sine wave reference generator is discussed. The frequency and amplitude are independently capable of being varied by means of two independent dc control voltages.
Abstract: A variable frequency, variable amplitude three-phase low frequency sine wave reference generator is discussed in this paper. The frequency and amplitude are independently capable of being varied by means of two independent dc control voltages. This reference generator is well suited for closed loop control applications such as constant frequency power supplies, constant amplitude power supplies, induction motor control requiring a finite ratio between amplitude and frequency, etc. The reversal of polarity of the dc voltage controlling the frequency reverses the phase sequence. The reference generator has been very satisfactorily used in the control of a three-phase ``subharmonic'' pulse width modulated inverter. The reference generator is also suitable for cycloconverter control.
Journal Article•
TL;DR: A novel scheme using the operational amplifier to obtain voltage controlled time delay for triggering SCR's is discussed, which has wide application in solid-state power control.
Abstract: A novel scheme using the operational amplifier to obtain voltage controlled time delay for triggering SCR's is discussed. The variation of the delay with voltage is smooth and undistrurbed by stray pulses. The circuit is flexible and any desired relationship between control voltage and time delay can be obtained. This has wide application in solid-state power control.
TL;DR: In this article, the authors describe a closed-loop system for the speed control of a separately excited d.c. motor fed from a dual converter, which makes possible regenerative braking and reversal of direction of rotation.
Abstract: The paper describes the design, construction and testing of a closed-loop system for the speed control of a separately excited d.c. motor fed from a dual converter. The dual converter makes possible regenerative braking and reversal of direction of rotation. There is only one firing unit and the firing pulses are diverted to the appropriate converter by a master controller. There are three control loops: one for armature current control, one for adjusting the firing angle of the oncoming converter, and one for speed control.
TL;DR: In this article, two methods for steady-state analysis of SCR controlled three-phase induction motors are described, one using the dynamic model of the motor arranged in state space form, and the other using the steady state harmonic equivalent circuits.
Abstract: Two methods for steady-state analysis of SCR controlled three-phase induction motor are described in the paper. The first method uses the dynamic model of the motor arranged in state space form. The second method uses the steady-state harmonic equivalent circuits of the motor. The results obtained by these methods are compared.
TL;DR: A set of dynamic filtering and prediction equations for use on a large scale gas pipe-line network are obtained on the basis of a simplified model and an algorithmic approach enables the filter to be structured and initialised automatically to particular applications on the input of commonly available network parameters.
Abstract: A set of dynamic filtering and prediction equations for use on a large scale gas pipe-line network are obtained on the basis of a simplified model. An algorithmic approach enables the filter to be structured and initialised automatically to particular applications on the input of commonly available network parameters. The proposed algorithm has relatively modest computational requirements. The response of the simplified dynamic network equations to a standard demand flow profile compares favourably with that previously obtained using a more complicated model. Simulation results illustrating filter performance to be satisfactory are also given.
TL;DR: In this article, an automatic phase control system adapted for the modulated subcarrier method of the microwave signal attenuation measurements is described, which is based on the same approach as the one described in this paper.
Abstract: An automatic phase control system adapted for the modulated subcarrier method of the microwave signal attenuation measurements is described.
TL;DR: In this article, preliminary tests on small quantities of sand with varying moisture content using a capacitive probe yielded reliable data as to the percentage of moisture in the sand and indicated that the design of the monitoring system is feasible, provided that further tests are carried out and that an actual full-scale system be evaluated.
Abstract: Preliminary tests on small quantities of sand with varying moisture content using a capacitive probe yielded reliable data as to the percentage of moisture. These tests indicate that the design of the monitoring system is feasible, provided that further tests are carried out and that an actual full-scale system be evaluated.
TL;DR: The Consolidated Edison Co. of New York was forced to purchase some 100 gas turbine generators with a total capacity of about 2700MW to meet its load demands for the early 1970 period.
Abstract: As a result of protracted delays encountered to obtain approval for the construction of nuclear and fossil units, and the long lead time to construct these, (approximately 10 years) the Consolidated Edison Co. of New York was compelled to purchase some 100 gas turbine generators with a total capacity of about 2700MW to meet our load demands for the early 1970 period. Within a 3-year period, we were thus able to add approximately 30% additional generation capacity to our system. While these gas turbines were designed primarily to meet peak demands, our system load requirements from 1971 to 1974 were at a level which necessitated continuous operation of these during the major portion of the day.
TL;DR: The techniques described in this paper can be inexpensively implemented to provide a statistical description of many laboratory or production processes with a minimum of operator intervention.
Abstract: This paper describes a microprocessor-based subsystem which was developed to provide a statistical description of the diameter of an arbitrary length of wire during the drawina or insulation process. The instrument, built around a 4-bit Intel microprocessor, computes the mean and standard deviation of 1000 data samples over a length of wire determined by the setting on a Binary-Coded Decimal (BCD) thumbwheel switch. The sample period may be varied from 2 milliseconds to 10 seconds. The statistical quantities are output on analog channels as well as digital displays. In addition to the statistical computation, the instrument has the option of playing back the data at arbitrary speeds and generatinq histograms of the data samples. The techniques described in this paper can be inexpensively implemented to provide a statistical description of many laboratory or production processes with a minimum of operator intervention.
TL;DR: In this paper, signal perturbation theory is used to enhance the quality of pictures formed on film by arrays of light emitting diodes, and models are presented for linear arrays and used to determine energy distributions on film for arbitrary boundary locations.
Abstract: A method is presented whereby signal perturbation theory is used to enhance the quality of pictures formed on film by arrays of light emitting diodes. Models are presented for linear arrays and used to determine energy distributions on film for arbitrary boundary locations.
TL;DR: In this paper, the expressions for the commutating capacitor voltage and current during the commutation period of the main and auxiliary thyristor in a chopper for a dc motor control system were deduced.
Abstract: This paper deduces the expressions for the commutating capacitor voltage and current during the commutation period of the main and auxiliary thyristor in a chopper for a dc motor control system. After a successful commutation, a certain amount of energy is ``stored'' in the circuit components, and for best component utilization this stored energy has to be minimized. The procedure of minimum stored energy in the commutation circuit has resulted in the selection of optimum values of commutating capacitors and inductors, and the values so obtained are more precisely defined than those indicated by early workers.
TL;DR: In this article, a high power PIN diode driver with built-in protecting network based on a self-timing mode is described, which is suitable in systems where a plurality of such drivers may be used or in testing instrumentation.
Abstract: In high power diode switching applications where overdrive is necessary, it is difficult to incorporate a short circuit feature in the driving circuitry. In this paper, a high power PIN diode driver with built-in protecting network based on a self-timing mode is described. The self-timing network is monitoring the output voltage and if a short exists, after a reverse-bias switching is completed, it acts to deviate the base current from the output driving device and reduces the load current by a few orders of magnitude. During every forward-bias to reverse-bias transition, the timing network introduces a delay to avoid interference with the normal operation of the circuit. The described driving circuit is suitable in systems where a plurality of such drivers may be used or in testing instrumentation.
TL;DR: In this article, an original time-optimal system of a stepping motor is discussed, where the proper switching moment for each phase of the motor is dependent on the normalized mechanical velocity wM, the normalized electromagnetic time constant Te and the normalized internal damping ration.
Abstract: An original time-optimal system of a stepping motor is discussed. The proper switching moment for each phase of the motor is dependent on the normalized mechanical velocity wM, the normalized electromagnetic time constant Te and the normalized internal damping ration.
TL;DR: This is a semi-tutorial paper whose main objective is to examine some aspects of implementing digital filters using microprocessors.
Abstract: This is a semi-tutorial paper whose main objective is to examine some aspects of implementing digital filters using microprocessors. Simulation results pertaining to the implementation of a first-order recursive filter via a microprocessor system are included.
TL;DR: In this paper, an alternator with rectifier excitation system on a micro alternator using a novel scheme of control with power transistor amplifiers is described, the theory of simulation is explained and salient features of the scheme are outlined.
Abstract: This paper describes the modeling of an alternator with rectifier excitation system on a micro alternator using a novel scheme of control with power transistor amplifiers. The theory of simulation is explained and the salient features of the scheme are outlined. Tests performed on the system have shown the accuracy and reliability of the scheme.
TL;DR: This paper describes a microcomputer programming facility, using an ``in-house'' minicomputer system which is capable of programning PROMs automatically from microprocessor source code.
Abstract: This paper describes a microcomputer programming facility, using an ``in-house'' minicomputer system which is capable of programning PROMs automatically from microprocessor source code. A programming system is described which contains cross-assemblers for Intel microcomputers and 1702A PROMs.