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The analytical program of a voltage source inverter (VSI)-fed permanent magnet synchronous motor (PMSM) with a half-controlled bridge converter and an LC filter is developed. The input voltage of the inverter, that is the capacitor voltage, has a ripple of double frequency of the source due to the phase control of the thyristor. The performance of the motor is significantly influenced by the ripple in the capacitor voltage. This influence can be evaluated by the analytical program.

A generalized analytical model is presented for thyristor- controlled variable inductors. The proposed model can represent the performance of various types of thyristor phase-controlled variable inductors (VI's), e. g., conventional, UM-concept, magnetically coupled reactor, and asymmetrically firing control types, by introducing two parameters: m and ?By means of numerical computation using this model, the characteristics of variable inductors can be clarified, and their characteristics can be compared with ease. This analytical model is very useful for deciding circuit configuration and design.

In the previous paper, the authors treated “Discharge Lamp Operation by Means of a Step-up Voltage Circuit by Back to Back Thyristor Pair.” The advantages of the new lamp operating system are based on the performance characteristics of this step-up voltage circuit, which depends delicately on the constants of the circuit and the phase control angle of thyristors. The obscurity of this dependability is an obstacle to the design calculation, together with the nonlinearity of the discharge lamp's own resistance.Thus, in this paper, with a view to investigate the step-up circuit, the analysis of the discharge lamp operating circuit has been carried out, assumed that both discharge lamp and L-ballast are replaced by a lumped, linearized equivalent load, that is, R-L load. The calculated results have revealed quantitatively the whole mechanism of the lamp operating circuit and provided the characteristics about output, power factor and efficiency that are the foundamental informations to design, and then given the prospects of the practical circuit design method.

Recently, electronics has been playing an important part in the development of new technology in the field of illuminating engineering. A new discharge lamp operating circuit described in this paper also belongs in the category.Authors have found that the performance characteristics of a step-up voltage circuit controlled by back to back thyristor pair, developed by them, would be naturally congenial to those of disch a rge lamp loads. This circuit, containing R, L and C in series, has the following unique features; that is, the direct or transless step-up voltage characteristics, the drooping characteristics of voltage-current relations when a consumer is loaded across terminals of C, L or L-C, and the flexibillity of these characteristics under control of the phase retard angle or thyristors.Experimental results have successfully demonstrated the anticipated advantages as follows.(1) Free from source voltage; supplying a lower source voltage, 30V, for example, the lamp of 100V ratings can be operated without a transformer.(2) Verstility; it is possible to adapt this citcuit to various kinds of types and capacities or discharge lamps.(3) Substitution of ballast; a the conventional ballast can be eliminated or replaced by a smaller one.(4) Controllability; the circuit is fit for optimal adjustment of atarting period, accurate lamp power regulation, more sensible dimming control, automatic dusk/dawn control, etc.

In the previous paper, the authors treated “Discharge Lamp Operation by Means of a Thyristor Inverter Type of Step-up Voltage Circuit”. The advantages of the new lamp operating system are based on the step-up function, the current limit function and controllability of a thyristor inverter type of step-up circuit. These characteristics, however, are realized only when the specified conditions, that is, circuit constant and driving frequency, are satisfied. So, before the design for practical use of the system is begun a detailed analysis of the circuit is required.Though the analysis of a single phase thyristor inverter circuit itself has been already reported in many literatures, there is nothing directly available for the purpose to make clear a series of the operations of the thyristor inverter type of step-up circuit for the discharge lamp operation.Thus, the authors have analized the circuit in the frequency domain (400 Hz-) in which the lamp load can be assumed to be an equivalent constant resistance when the fluorescent lamp is used as the discharge lamp. The results have revealed quentitatively the whole mechanism of the lamp operating circuit and given the prospects of the practical circuit design method.

Catering for the variety of the requests of modern illuminating technology, the various type of discharge arc lamps, such as fluorescent, mercury, sodium, etc., are utilized according to each merit respectively, and therefore the lamp operating circuits for them have to be provided with various configurations and capacities. However, it seems that the common requirements for these circuitperformances are sufficient ignition and reignition voltage, efficient ballastting function and adaptability to operating conditions, for example, line voltage fluctuation, surrounding temperature variation, etc.Recently, some new lamp operating circuits and/or systems by means of semiconductor devices have been developed to satisfy the above requirements in smaller size, lighter weight and higher efficiency. A new discharge lamp operating circuit described in this paper also belongs in the category, and the experimental results have successfully demonstrated the advantages as follows.(1) By supplying a lower d. c. source voltage, d. c. 12 V, for example, the lamp of a. c. 100 V ratings can be operated without a transformer.(2) Sufficient ignition and reignition voltage can be always secured.(3) It is also possible to adapt this circuit to various kinds of types and ratings of discharge lamps by frequency control.(4) The drooping characteristics of voltage-ampere relationship of this circuit and also capability of higher frequency operation results in the elimination or reduction of ballast loss and the rise of lamp efficiency. Thus, consequently the overall efficiency can be significantly improved.(5) The circuit is fit for lamp power regulation, constant current control, automatic dusk, dawn control, etc.

Most of the existing papers have dealt with the torque pulsation of an inverter-fed AC motor caused by the behaviour of the inverter. In industrial applications the DC source is achieved by rectifying the AC supply. Therefore the behaviour of this rectifier also influences the torque pulsation. This paper describes analytically the influences of not only the behaviour of the inverter but also the behaviour of the rectifier on the motor torque. The torque pulsation is estimated by using three estimation methods. The selection of filter constants is also discussed.