Fluorescent lamps have a special V-I characteristic. Their incremental impedance is defined and studied in the frequency domain. It is found that the negative incremental impedance of a fluorescent lamp can be characterized by a right half plane zero. The existence of such a result is explained by the modified Francis equation. Two ballasting approaches, series impedance and close-loop operation, are proposed to stabilize lamp operation. Stability criteria based on the Nyquist criterion are developed for both approaches.

Negative incremental impedance and stability of fluorescent lamps

A general package for harmonic-domain computation is described. It consists of a set of routines which can be used by developers of programs for power system harmonic applications. The most basic routines have been listed. The package represents nonlinear characteristics by fitting the characteristic with a polynomial, for which special harmonic domain processing via convolutions has been developed, or by directly applying a fast Fourier transform. A model in the form of a differential equation is derived for the electric arc. It is based on simple energy balance considerations and therefore is expected to be generally valid. The computational results compare well with existing measurements. The arc model can be used for discharge lamps or for arc furnaces. >

A harmonic domain computational package for nonlinear problems and its application to electric arcs

A new PSpice dynamic fluorescent lamp model based on high-frequency lamp characteristics is presented. The new model avoids the convergence problems found when using the Mader-Horn lamp model. A systematic approach is developed to derive the lamp model parameters from experimental data. Simulations are shown to agree closely with experimental data.

PSpice High-Frequency Dynamic Fluorescent Lamp Model

A new PSpice dynamic fluorescent lamp model based on high-frequency lamp characteristics is presented. The new model avoids convergence problems found when using the Mader-Horn lamp model. A systematic approach is developed to derive the lamp model parameters from experimental data. Simulations are shown to agree closely with experimental data.

http://ieeexplore.ieee.org/iel3/3567/10676/00500508.pdf

PSpice high frequency dynamic fluorescent lamp model

A probe for use on a coordinate positioning machine has a stylus supporting assembly (15), which supports a stylus (14) for three dimensional movement relative to the probe housing (10). The stylus supporting assembly (15) comprises a first member (16) mounted on the housing (10) and having a first plane surface (18). A second member (20) has a second plane surface (22) which is retained against the first plane surface (18) by magnets (24). The second member (20) may move in all directions in the XY plane relative to the first member (16) on an air bearing (26), and rotation of the second member (20) relative to the first member (16) is prevented by a spring bellows (30). The stylus (14) is fixedly connected to a third member (42) having plane surfaces (52A,B), which are retained against corresponding surfaces (50A,B) provided on the second member (20) by magnets (56), and for movement relative to the second member (20) in the Z direction on air bearings (48). The second and third members (20,42) may be provided in a light but stiff structure to lower the inertia of the stylus supporting assembly (15) and such a structure may for example be a honeycomb material. Movement of the stylus (14) in each of the X,Y,Z, directions is transduced by a series of transducers (62A,B;64A,B;66A,B).

Position sensing probe

A nonlinear dynamic model of the terminal voltagecurrent (V-I) characteristics of a mercury arc lamp operating at various power levels which can be used in the computer design of lamp ballast circuits is described. An experimental and efficient computational procedure is developed which determines the values for six model constants that cause the model to duplicate actual lamp behavior. This model is shown to be accurate within five percent in simulating lamp voltage and current waveforms when operated at frequencies from dc to 30 kHz. An example of a computer design of a high frequency ballast circuit is presented using the lamp model as the dynamic load in the ballast circuit.

A Model of a Mercury Arc Lamp's Terminal V-I Behavior

A coordinate measuring machine probe of the type including an arrangement for detecting contact with a surface, in which a light source and a plurality of photocells are arranged to generate an electrical signal upon probe pivoting motion by detection changes in light intensity sensed by the photodetectors. A summing circuit measures the total incident illumination of the photocells and controls the light source to maintain the total illumination of the photocells to be constant.

Contact sensing probe for a measuring apparatus

A MERCURYarclampbehaves asanonlinear time-varying powerresistor whenoperated inseries withasinusoidal powersource andacontrolling ballast device. Theinstantaneous value ofthelampresistance isinfluenced bythe source voltage variation, theballast circuit characteristics, and theinternal physical processes within thearcdischarge itself. Since future lamp-ballast systems whichoffer moreefficient light generation will depend uponsolid-state circuits toconvertandcontrol powerdelivered tothelamp, itisbecoming moreimportant toaccurately characterize thedynamic resistance ofthelampsothateffective system design canbe

Edward L. Laskowski

Papers

A Model of a Mercury Arc Lamp's Terminal V-I Behavior

Contact sensing probe for a measuring apparatus

A Modelofa Mercury ArcLamp'sTerminal V-IBehavior