Electric Equivalent Model for Induction Electrodeless Fluorescent Lamps

IEEE TRANSACTIONS ON POWER ELECTRONICS, VOL. 28, NO. 7, JULY 2013

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Electric Equivalent Model for Induction Electrodeless Fluorescent Lamps M. F. da Silva, N. B. Chagas, M. E. Schlittler, J. Fraytag, T. B. Marchesan, Member, IEEE, F. E. Bisogno, J. Marcos Alonso, Senior Member, IEEE, and R. N. do Prado, Member, IEEE

Abstract—This paper presents an electric equivalent model applied to induction electrodeless fluorescent lamps. The model is based on passive components and takes into account the real and reactive lamp power. The presented model and its obtention methodology will be an important tool for ballast designers. One of the most important features of the proposed methodology is the concern regarding core losses and lamp reactive characteristics, because nowadays there are no electric models including these characteristics. In order to obtain and validate the electrodeless lamp model, a series–parallel resonant half-bridge inverter is used as ballast. Plasma and lamp windings are modeled as resistances and reactances depending on the lamp power. Simulations employing the proposed model are also presented, showing an excellent agreement with experimental results. Index Terms—Electrodeless fluorescent lamps, equivalent model, high frequency.

I. INTRODUCTION HE electrical discharge without electrodes was discovered by J. W. Hittorf in 1884, and the first electrodeless lamp was exhibited by N. Tesla in New York in 1891 [1]. The induction lamp principles were patented in 1907 by P. C. Hewitt [1]. The induction electrodeless fluorescent lamp (IEFL) differs from the traditional fluorescent lamp (FL) mainly by the electrodes absence. Typically, the IEFL operating frequency goes from hundreds of kilohertz to tens of megahertz [2]. Therefore, high frequency electronic ballasts must be employed for driving these lamps. In this context, electrodeless lamp modeling is an essential tool for electronic ballast designers. Thus, the energy transfer from the coil windings to the plasma has been the subject of several studies in the recent literature [3], [4]. When the high-frequency electric current flows through the lamp coil windings, a magnetic field is created. The magnetic

T

Manuscript received May 21, 2012; revised August 27, 2012; accepted October 23, 2012. Date of current version December 24, 2012. Recommended for publication by Associate Editor M. Ponce-Silva. M. F. da Silva, N. B. Chagas, M. E. Schlittler, J. Fraytag, T. B. Marchesan, F. E. Bisogno, and R. N. do Prado are with the Federal University of Santa Maria, Santa Maria-RS 97105-900, Brazil (e-mail: marcelo@gedre. ufsm.br; [email protected]; [email protected]; [email protected]; [email protected]; [email protected]). J. M. Alonso is with the Department of Electrical Engineering, Universidad de Oviedo, Gijón 33203, Spain (e-mail: [email protected]). Color versions of one or more of the figures in this paper are available online at http://ieeexplore.ieee.org. Digital Object Identifier 10.1109/TPEL.2012.2227501

Fig. 1. IEFLs models. (a) ICETRON/ENDURA, from OSRAM Sylvania, 250 kHz. (b) GENURA from GE 2.5 MHz.

field induces an electric current through the plasma that accounts for the light generation. The main difficulty for modeling the IEFL is to determine its equivalent electrical parameters, resistances, and reactances that represent the lamp discharge behavior. Contributions on this subject have been done in [5] and [6], but the lamp was modeled by a purely resistive characteristic and the cores losses were neglected. In this paper, the lamp and the cores losses parameters are considered to determine the complete lamp electrical model. Thus, the IEFL can be simulated by means of its equivalent impedance, making the ballast design more straightforward and allowing for the determination of the electrical characteristics of the entire system. The possibility to simulate the whole system (ballast and lamp) with an accurate lamp model, provides useful information for the system optimization and, consequently, for reducing design costs. The model has been developed by using experimental data and verified throughout simulations. Although the industry may provide several types of IEFLs, the lamp used in this paper is manufactured by OSRAM (ENDURA 100 W) as shown in Fig. 1(a). The lamp operating frequency (f ) is 250 kHz and the principle of energy transfer from the coils to the discharge is the same as in a transformer. The coils in parallel, with N turns each, act as the transformer primary winding [7] and the plasma created inside the lamp acts as a one-turn secondary winding. The main features of commercial IEFLs are good luminous efficiency, the possibility of obtaining higher power ratings than FLs owing to electrode absence, and most importantly very long lifetime. Commercial datasheets indicate lifetime up to 100 000 h [8]. Owing to the characteristic of long lifetime, these lamps are suitable for street lighting, in places with difficult access in which the lamp replacement has a high maintenance cost. Moreover, the IEFL dimming is also possible and recommended

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the complete circuit for simulation is presented. Section V presents a comparative analysis between the model simulation results and experimental tests. Finally, Section VI provides the conclusion of this paper. II. IEFL EQUIVALENT ELECTRICAL CIRCUIT

Fig. 2.

V −I curve of the IEFL ENDURA – 100 W.

in many applications [9], [10]. Some IEFLs present an external coil, as shown in Fig. 1(a), others use a spherical discharge volume with the coil inside the bulb, as shown in Fig. 1(b). The IEFLs negative impedance characteristic points to the necessity of a ballast to limit its current. Fig. 2 shows the lamp voltage V1 versus the lamp current I1 at its rated power (100 W) and also at a reduced power (30 W), where the negative impedance behavior can be observed. In IEFL discharge, it can be assumed that the voltages and the currents are nearly sinusoidal, because at the operating frequency the discharge relaxation time (around 400 μs) is much longer than the driving period (4 μs). Thus, the lamp may be considered as a quasi-linear load having constant impedance over the driving period [11]. This allows for the lamp to be modeled as a set of equivalent impedances. However, under dimming operation the lamp equivalent impedance changes at different lamp power and a model capable of emulating the IEFL behavior during this process is required. Some factors can influence the IEFL electrical equivalent feature, such as: plasma conductivity, core equivalent resistance, mutual inductance, lamp temperature, and coupling coefficient between coils and lamp. Several previous works have dealt with lamp modeling under dimming operation, mainly for FLs. For example, the FL physical parameters are studied and modeled in [12], [13]. The literature also shows FL models to represent the variable electrical parameters as a function of the lamp power. Among them the tangential model [14], the Mader–Horn model [15] and the polynomial model [16] have been proposed. However, these models usually represent only variable resistors, which is not sufficient for a complete IEFL modeling. In this paper, the proposed model employs variable resistances and reactances to represent the lamp behavior and uses polynomial regression to emulate the parameters variation. Thus, three parameter variations are considered in the proposed model: equivalent core losses resistance, equivalent plasma resistance, and equivalent lamp reactance. All of them are approximated by polynomial functions depending on the IEFL total real power. This paper is organized as follows: Section II presents the IEFL equivalent circuit. Section III shows the IEFL model development and the experimental data acquirement. In Section IV,

In order to determine the IEFL equivalent circuit, considering dimming feature, it is necessary to analyze the IEFL taking into account its constructive characteristics. As stated before, the lamp and external coils may be analyzed as a transformer. The electronic ballast provides power to the primary winding and the lamp is the load of the transformer secondary side [11]–[17]. During the IEFL starting process there is a capacitive discharge, in which the required ignition voltage depends on the lamp constructive details, such as number of turns N , but it is independent on the driving frequency [18]. In IEFL ENDURA the number of turns used is N = 18. The ignition takes place when the azimuthal electric field, induced by the coil, is sufficiently high to maintain the discharge. The study of discharge transitions within the IEFL is out of the scope of this paper. Interesting analysis on this aspect has been carried out in [19] and [20]. The electrical circuit that can be used to model the IEFL behavior is illustrated in Fig. 3. The lamp, without its cores, is represented by the plasma resistance Rlam p2 and an equivalent parallel reactance Xlam p2 , as shown in Fig. 3(a). These values can be reflected to the transformer primary side, considering a unitary transformer coupling coefficient [21], as illustrated in Fig. 3(b). As it will be demonstrated later, the lamp reactance can be represented by a parallel capacitance, as shown in Fig. 3(c). This capacitive characteristic was observed during the laboratory experiments. Similar behavior was observed in [18] for an IEFL operating at higher frequency. In [11], where a similar IEFL is used, the lamp also presented the same capacitive characteristic. The capacitive characteristic observed on the lamp model is related to two factors: lamp geometry (capacitance between plasma and the lamp wall) and coil capacitance [18]–[22]. However, owing to the effect of the primary magnetizing inductance Lcore , the complete lamp electrical circuit presents an inductive behavior that can be represented by a total equivalent inductance Leq , as shown in Fig. 3(d). In order to separate the different physical effects that are present in the lamp, this paper proposes an electrical model that considers the lamp by both its capacitive and resistive components. A variable resistor Rlam p represents the plasma real power and a variable capacitance Clam p represents the lamp reactance Xlam p . Both of them will vary according to the lamp power. The core losses are modeled by another lamp-power-dependent resistor Rcore , while the magnetizing inductance Lcore is assumed independent of the lamp power. On the other hand, leakage inductance and winding resistance can be neglected, because the IEFL coupling factor is nearly unit [21] and windings ohmic losses are negligible compared to cores losses Pcore [11]. Thus, the IEFL equivalent circuit referenced to the primary side of transformer model is shown in Fig. 3(c). Fig. 4 shows the IEFL voltage and current phasor diagram, referenced to the primary side of the transformer. In

DA SILVA et al.: ELECTRIC EQUIVALENT MODEL FOR INDUCTION ELECTRODELESS FLUORESCENT LAMPS

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Fig. 3. (a) IEFL equivalent electrical model. (b) Model with the lamp parameters referenced to the primary. (c) IEFL simplified model considering the lamp and the cores parameters. (d) IEFL simplified model.

Fig. 5. Fig. 4.

Prototype for the experimental data acquirement.

IEFL phasor diagram.

Figs. 3 and 4, I0 represents the addition of the magnetizing current IL core and the core losses current IR core . I2 represents the total bulb lamp current, which is given by the addition of the IC lam p capacitive current and the IR lam p plasma current. These magnitudes represent RMS values, and the same magnitudes with apostrophe represent peak values. The angle Ø1 represents the phase angle between lamp input voltage and current. III. DEVELOPMENT OF THE IEFL ELECTRIC MODEL A. Experimental Data Acquirement and Model Equations The main idea of the proposed model is to consider the IEFL equivalent circuit (coils and lamp tube) and define the lamp parameters values based on available electrical measurements. Thus, in order to develop the model it becomes necessary experimental data acquirement. This means that each lamp type has its own parameters that shall be obtained through experimental results. Experimental data for the IEFL modeling were obtained by using a half-bridge inverter, along with a series–parallel resonant filter (LCC), fed by a dc-voltage source (VBUS ). The LCC filter components were calculated based on [23]. The experimental data were obtained by the following procedure: the IEFL was maintained at rated power until the discharge

reached its steady state. Then, the dc voltage applied to the halfbridge inverter was reduced in 10 V steps. A 15-min interval was considered between each step for data acquisition, allowing the lamp to reach steady state. This procedure was repeated until the input voltage was not high enough to maintain the discharge and the lamp turned OFF. With regard to the effect of the ambient temperature on the lamp parameters it has been reported in [18] that stabilized values of the maintaining coil current and voltage in the lamp operated with the amalgam did not vary significantly with the ambient temperature in the range –10 ◦ C to 40 ◦ C. Therefore, it is expected that the developed model will be useful in a wide range of ambient temperature. Fig. 5 shows the employed topology for the experimental data acquisition. The operating frequency (f ) is 250 kHz. The voltage applied to the lamp V1 was acquired using a voltage probe from TEKTRONIX model P5200 and current I1 was measured using a current probe from TEKTRONIX model TCPA300. The oscilloscope used was a TEKTRONIX model DPO2014. The VBUS voltage was supplied by a dc-voltage source from SUPLLIER model FCC 400-50i. Through the measurement of lamp input voltage V1 and current I1 , the following lamp parameters may be obtained: real power P , apparent power S, reactive power Q, and phase angle Ø1 .

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1) Calculation of the IEFL Equivalent Impedance: The experimental data makes it possible to calculate the IEFL impedance. The IEFL equivalent resistance [Fig. 3(d)] referenced to the primary side (Req ) is calculated by using

TABLE I EXPERIMENTAL DATA

V12 . (1) P The IEFL equivalent reactance XL eq is given by means of Req =

XL eq =

V12 . Q

(2)

The IEFL equivalent inductance Leq is calculated by using Leq =

XL eq . 2·π·f

(3)

2) Calculation of the IEFL Core Parameters: The values of real power consumed by the two cores were also obtained experimentally. In order to obtain Rcore , an additional experiment was conducted, where the core losses were obtained in only one of the cores as function of the RMS voltage applied to it. However, Pcore is the equivalent power in two cores. The electronic circuit employed is the same used before to obtain the lamp impedance characteristics (see Fig. 5). The entire lamp was replaced by the core and a parallel equivalent resistance. The core was taken from the lamp and an external resistor of approximately 410 Ω was placed in parallel with the coil so that the lamp voltage for each lamp power operation point can be attained. This external resistance has the same value of IEFL resistance Req at the nominal operating point. This makes possible to measure the core losses at each voltage level. All the losses measured were attributed to the core because as explained before the winding resistance may be neglected. Then, by using (4), the core resistance Rcore , for the IEFL model, may be determined Rcore =

V12 . Pcore

(4)

The coil magnetizing inductance Lcore was measured using an LCR Meter, obtaining 1000 μH for each core. A similar value was also obtained in [11] and [24]. 3) Calculation of the IEFL Lamp Electrical Parameters Referenced to the Primary Side: Using the values obtained from (1) and (4) it is possible to obtain the plasma resistance Rlam p through Rlam p =

Rcore · Req . Rcore − Req

(5)

In addition, using Lcore and IEFL equivalent reactance measurements (XL eq ) it is possible to obtain the lamp reactance from XL core · XL eq . (6) XClam p = XL core − XL eq Experimental results, as explained before, point to a lamp capacitive component that is calculated by Clam p =

1 . 2 · π · f · XClam p

(7)

B. Obtained Experimental Data The obtained experimental results are presented in Table I. The measured parameters variation according to the converter bus voltage can be better observed in Figs. 6–9. Fig. 6 presents the real and reactive power variation; Fig. 7 shows the IEFL RMS voltage and current; Fig. 8 shows the IEFL impedance and phase angle Ø1 ; and Fig. 9 shows the IEFL plasma resistance and lamp capacitance. The core real power as function of its RMS voltage is shown in Fig. 10. Fig. 8 shows that, decreasing the IEFL power, the impedance angle is increased, making the operation even more inductive. It ensures the maintenance of the system ZVS operation. Using the experimental data and calculated values, a polynomial regression function has been employed to determine the equations that represent the IEFL parameters variation as function of its real power. The coils characteristics were considered to be inside the IEFL lamp model. Equation (8) shows the polynomial function for Rlam p (P ). The values of the different coefficients are presented in Table II Rlam p (P ) = A4 · P 4 + A3 · P 3 + A2 · P 2 + A1 · P + A0 . (8) Fig. 11 shows the plasma resistance variation referenced to the primary side as function of the IEFL real power. It can be observed that when decreasing the IEFL real power, there is a nonlinear increase in Rlam p (P ). In this case, Rlam p (P ) may be approximated by a fourth order polynomial equation. The polynomial function for Rcore (P ) is presented in (9). The calculated coefficients are presented in Table II Rcore (P ) = B4 · P 4 + B3 · P 3 + B2 · P 2 + B1 · P + B0 . (9)


Fig. 6.

IEFL real and reactive power as a function of V B U S variation.

Fig. 7.

IEFL RMS voltage and current as a function of V B U S variation.

Fig. 9.

Fig. 10.

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R la m p and C la m p as function of V B U S variation.

P c o re as function of lamp RMS voltage.

Experimental results for the same lamp operating in 200 and 300 kHz were also performed, i.e., 50 kHz below and above the IEFL nominal frequency. It was found that the IEFL parameters behaviors show the expected variations with frequency as might be observed in Figs. 14 and 15. Fig. 16 shows the inductance Leq given by Lcore and Clam p . IV. ORCAD/PSPICE MODEL Fig. 8.

IEFL impedance and total phase angle as a function of V B U S variation.

Fig. 12 shows the core equivalent resistance variation as a function of the IEFL real power. Decreasing the lamp power increases the RMS lamp voltage and consequently the core losses increase. As can be observed in Fig. 12, this is represented by a decrease in Rcore . Equation (10) presents the polynomial regression for Clam p (P ). The calculated coefficients are presented in Table III. Fig. 13 shows the lamp capacitance variation (reflected to the primary side) as function of the IEFL real power. An increase in Clam p can be observed with the IEFL power decrease. This result was as expected because when decreasing the IEFL power, the plasma carrier density is lower, thus reducing the equivalent distance between the plasma and the lamp wall and increasing its capacitive component [22] Clam p (P ) = C4 · P 4 + C3 · P 3 + C2 · P 2 + C1 · P + C0 . (10)

This section presents an example of the implementation of the ENDURA 100 W lamp model, obtained by the methodology explained before. Although the model is implemented in Orcad/PSpice it is not limited to this software. Fig. 17 presents the circuit used for model simulation. It consists of the electronic circuit (ballast) and several function blocks to represent the lamp parameters variation. Each block will be explained in detail. A. Calculation of the IEFL Real Power (P ) The circuit used for the IEFL real power simulation is shown in Fig. 17. The equations are represented as follows: 1) V (1)—is the IEFL voltage; 2) I(V )—is the current sensor; 3) V (1,2)—is the plasma current, reflected to the primary. IEFL parameters are modeled as a function of the real power, which is the average value of the instantaneous power. In Fig. 17(a) the current source (G1 ), emulates the magnitude of

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TABLE II R la m p (P) AND R c o re (P ) CALCULATED DATA

Fig. 11.

R la m p as function of IEFL real power variation.

Fig. 13.

C la m p as function of IEFL real power variation.

Fig. 12.

R c o re as function of IEFL real power variation.

Fig. 14.

IEFL R e q for different frequencies.

TABLE III C la m p (P ) CALCULATED DATA

power P G1 = V (1) · I(V ).

(11)

The values of capacitor C1 and resistor R1 are defined so that the RC filter’s cutoff frequency is substantially below the IEFL operating frequency. The cutoff frequency of 2 kHz was adopted for the low-pass filter employed in this model. B. Plasma Resistance Model Reflected to the Primary Side

the lamp instantaneous power, as defined in (11). This current source is applied to a parallel RC circuit (R1 and C1 ) that represents a low-pass filter with time constant defined by R1 C1 , causing the voltage at node 4 [V(4)] to represent the IEFL real

The plasma resistance model reflected to the primary side (Rlam p ) is shown in Fig. 17(b). It is given in terms of the IEFL real power. The voltage at node 3 is numerically equivalent to Rlam p . The voltage source E1 models the plasma resistance, reflected to the primary side, which is mathematically calculated using expression (8). The voltage source E1 is responsible for


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TABLE IV LAMP POWER, VOLTAGE, AND CURRENT COMPARISON

Fig. 15.

IEFL C la m p for different frequencies.

TABLE V CORE AND PLASMA REAL POWER COMPARISON

Fig. 16.

IEFL L e q for different frequencies.

Fig. 17. IEFL simulation model. (a) Real Power (P ). (b) Plasma Resistance (R la m p ). (c) Cores Equivalent Resistance (R c o re ). (d) Lamp Equivalent Capacitance (C la m p ).

emulating the resistance value corresponding to the lamp power, which is represented by the voltage at node 4. The voltage generated by E3 numerically represents the lamp resistance multiplied by the current flowing through it, as shown in (12). In order to compensate the effect of the sensing resistor R, its voltage drop is subtracted from the voltage generated by E3 E3 = V (3) · V (1, 2) − V (1, 2).

(12)

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Fig. 18. IEFL voltage and current experimental and simulation results for different bus voltages. Voltage Scales: 250 V/div. Current Scales: 1 A/div. Time Scales: 2 μs/div. (a) 300 V Experimental. (b) 300 V Simulated. (c) 220 V Experimental. (d) 220 V Simulated. (e) 140 V Experimental. (f) 140 V Simulated.

C. Cores Equivalent Resistance Model The core equivalent resistance (Rcore ) is implemented as shown in Fig. 17(c) as a function of the IEFL real power. The node 8 voltage [V(8)] represents numerically the value of Rcore , and it is generated by the voltage source E4 expressed as in (9) and it is responsible for emulating the cores resistance value as a function of the lamp power. Therefore, node 8 voltage has a magnitude equal to the core resistance. The current source G4 is responsible for emulating the current through the Rcore as shown in V (1) . (13) G4 = V (8) D. Lamp Capacitance Model Referenced to the Primary Side The lamp capacitance model reflected to the primary side (Clam p ) is presented in Fig. 17(d). Node 6 voltage [V(6)] represents numerically the value of Clam p , and the voltage source E2 is equal to the lamp capacitance model, mathematically calculated in (10). This voltage source is responsible for emulating the capacitance value for each real lamp power. Therefore, the node 6 voltage presents a magnitude equal to the lamp capacitance.

The current source G2 is responsible for emulating the current with an amplitude equal to the IEFL voltage, as in (14). Since G2 current flows through the inductance L and the inductance voltage corresponds to the Clam p voltage time derivative. Thus, voltage in node 5 represents the IEFL voltage. The current source G3 is responsible for emulating the lamp reactive current, as in (15) G2 = V (1)

(14)

G3 = V (5) × V (6).

(15)

The value of R (see Fig. 17), employed in the auxiliary circuits with dependent voltage sources, does not influence the model results and can be selected to solve simulation convergence problems. V. COMPARATIVE ANALYSIS BETWEEN SIMULATION AND EXPERIMENTAL RESULTS In order to validate the model and its obtaining methodology, simulations were performed for each bus voltage used in experimental data acquisitions.


Fig. 19.

IEFL real and apparent power errors.

Fig. 20.

IEFL RMS voltage and current errors.

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Fig. 22.

Plasma and cores real power errors.

Fig. 23.

Real power errors for the proposed and the constant reactance model.

VI. CONCLUSION

Fig. 21.

Phase angles Ø 1 errors.

Table IV presents the experimental and simulated values for real (P ) and apparent (S) power, RMS voltage (V1 ), and current (I1 ). Table V presents the experimental and simulated values of the plasma real power Pplasm a , core real power Pcore , and the IEFL total phase angle Ø1 . The Fig. 18 shows the experimental and simulation results for different bus voltages. The simulation results are in agreement with the acquired experimental results for the IEFL in the steadystate operation. Phase angles and amplitudes are very similar to those obtained in the experimental results. The power magnitude errors are shown in Fig. 19. The average error for the real and reactive power was 1.66% and 1.94%, respectively. The average errors for the RMS voltage and current in the IEFL (see Fig. 20) and the phase angle (see Fig. 21) are less than 2.5%. The Pplasm a and Pcore magnitude errors are shown in Fig. 22, where average errors of 1.08% and 5.39% were calculated, respectively. The largest errors usually occur in the lower bus voltages because in this situation, the discharge is close to extinguishing. At this point, few watts in absolute error represent higher percentage errors. The errors presented by the proposed model are lower than observed in previous papers [5], [6]. This is mainly due to the consideration of the lamp reactance variation performed in present model. Fig. 23 shows the comparison between the real power errors presented by the proposed model and another one that considers only the variation of the IEFL equivalent resistance, maintaining constant the reactance.

This paper has proposed a methodology to develop an IEFL equivalent electrical model. Initially, important IEFL features were presented along with the differences of the proposed model with those already available in the literature. Obtained results in Section V show that the simulation model is extremely valid for predicting the operation behavior of the IEFL in steady state. The proposed model does not represent the lamp dynamic behavior. This accuracy is obtained because the model does not consider only the plasma resistance variation, but also the lamp reactive component variation, as well as core losses. The voltage and current waveforms shape and phase angles between them showed similar characteristics in simulation and experimental results. The proposed methodology is applicable to the IEFL model considering coupling coefficient near unity and may also be used to different IEFL working frequencies. Despite the implementation of the model being in the simulation software OrCAD/PSpice, it can easily be extended to other simulation programs. REFERENCES [1] D. O. Wharmby, “Electrodeless lamps for lighting: A review,” IEE Proc. A, Sci., Meas. Technol., vol. 140, no. 6, pp. 465–473, Nov. 1993. [2] J. W. Shaffer, “The development of low frequency, high output electrodeless fluorescent lamps,” J. Illum. Eng. Soc., vol. 28, no. 1, pp. 142–148, 1999. [3] R. B. Piejak, V. A. Godyak, and B. M. Alexandrovich, “A simple analysis of an inductive RF discharge,” Plasma Sources Sci. Technol., vol. 1, no. 3, pp. 179–186, Jul. 1992. [4] V. A. Godyak, “Bright idea, radio-frequency light sources,” IEEE Ind. Appl. Mag., vol. 8, no. 3, pp. 42–49, May/Jun. 2002. [5] Yuming Chen and Dahua Chen, “Simulation the impedance of electrodeless fluorescent lamp,” in Proc. 41st IAS Annu. Meeting Ind. Appl. Conf., Oct. 8–12, 2006, vol. 1, pp. 242–245. [6] S. Ben-Yaakov, M. Shvartsas, and J. Lester, “A behavioral SPICE compatible model of an electrodeless fluorescent lamp,” in Proc. 17th Annu. IEEE Appl. Power Electron. Conf. Expo., 2002, vol. 2, pp. 948–954. [7] J. N. Lester and B. M. Alexandrovich, “Ballasting electrodeless fluorescent lamps,” J. Illum. Eng. Soc., Beverly, MA, vol. 28, pp. 1–11, Jan. 6, 1999.

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[8] M. F. da Silva, J. de P Lopes, N. B. Chagas, A. R. Seidel, M. A. D. Costa, and R. N. do Prado, “High power factor dimmable lighting system for electrodeless fluorescent lamp,” in Proc. Int. Symp.Power Electron. Electr. Drives Autom. Motion, Jun. 14–16, 2010, pp. 379–384. [9] Haiyan Wang, A. V. Stankovic, L. Nerone, and D. Kachmarik, “A novel discrete dimming ballast for linear fluorescent lamps,” IEEE Trans. Power Electron., vol. 24, no. 6, pp. 1453–1462, Jun. 2009. [10] Nan Chen and H. S. Chung, “A dimming module for controlling power supplying to a fluorescent lamp ballasted by a nondimmable electronic ballast,” IEEE Trans. Power Electron., vol. 25, no. 10, pp. 2541–2551, Oct. 2010. [11] E. Stanic and V. Tanach, “A new approach to the evaluation of the discharge parameters of the electrodeless fluorescent lamps,” Plasma Sources Sci. Technol., vol. 13, no. 3, pp. 515–521, Jul. 2004. [12] A. J. Holloway, R. C. Tozer, and D. A. Stone, “A physically based fluorescent lamp model for a SPICE or a simulink environment,” IEEE Trans. Power Electron., vol. 24, no. 9, pp. 2101–2110, Sep. 2009. [13] G. Zissis and D. Buso, “Using full physical model for fluorescent lamps in ballast engineering,” in Proc. 38th IEEE Ind. Appl. Soc. Annu. Meeting, Oct. 2003, vol. 2, pp. 537–541. [14] M. Cervi, A. R. Seidel, F. E. Bisogno, and R. N. do Prado, “Fluorescent lamp model employing tangent approximation,” in Proc. IEEE 33rd Annu. Power Electron. Spec. Conf., 2002, vol. 1, pp. 187–191. [15] U. Mader and P. Horn, “A dynamic model for the electrical characteristics of fluorescent lamps,” in Proc. IEEE Ind. Appl. Soc. Annu. Meeting, Conf. Rec., Oct. 1992, vol. 2, pp. 1928–1934. [16] N. Onishi, T. Shiomi, A. Okude, and T. Yamauchi, “A fluorescent lamp model for high frequency wide range dimming electronic ballast simulation,” in Proc. 14th Annu. Appl. Power Electron. Conf. Exposition, Mar. 1999, vol. 2, pp. 1001–1005. [17] T.-E. Jang, H.-J. Kim, and H. Kim, “Dimming control characteristics of electrodeless fluorescent lamps,” IEEE Trans. Ind. Electron., vol. 56, no. 1, pp. 93–100, Jan. 2009. [18] O. Popov and J. Maya, “Characteristics of electrodeless ferrite-free fluorescent lamp operated at frequencies of 1-15 MHz,” Plasma Sources Sci. Technol., vol. 9, no. 2, pp. 227–237, 2000. [19] M. Abdur Razzak, Kenji Kondo, Yoshihiko Uesugi, Noriyasu Ohno, and Shuichi Takamura, “Transition from electrostatic-to-electromagnetic mode in a radio-frequency Ar inductively coupled plasma in atmospheric pressure,” J. Appl. Phys., vol. 95, no. 2, pp. 427–433, Jan. 2004. [20] N. S. Yoon, B. C. Kim, J. G. Yang, and S. M. Hwang, “A theoretical formula of E-H discharge transition power in a transformer-coupled discharge,” IEEE Trans. Plasma Sci., vol. 26, no. 2, pp. 190–197, Apr. 1998. [21] E. Stanic and V. Tanach, “Investigation of the electrical discharge parameters in electrodeless inductive lamps with a re-entrant coupler and magnetic core,” Plasma Sources Sci. Technol., vol. 15, pp. 465–473, 2006. [22] J. J. Gonzalez and A. Shabalin, “Electrical characteristics of plasma sheaths in transformer-coupled toroidal discharges,” Plasma Sources Sci. Technol., vol. 12, no. 3, pp. 317–323, 2003. [23] J. C. W. Lam and P. K. Jain, “A novel high-power-factor single-switch electronic ballast,” IEEE Trans. Ind. Appl., vol. 46, no. 6, pp. 2202–2211, Nov./Dec. 2010. [24] S.-B. Han, S. Park, E. Song, H.-G. Jeong, and B.-M. Jung, “Analysis of effects of inductance component in electrodeless lamp on ballast performances,” in Proc. 7th Int. Conf. Power Electron., Oct. 2007, pp. 330–333.

M. F. da Silva was born in São Paulo, Brazil, in 1970. He received the B.S. and M.Sc. degrees in electrical engineering from the Federal University of Santa Maria, Santa Maria, Brazil, in 1995 and 2000, respectively. He is currently working toward the Ph.D. degree in power electronic applied to lighting systems. Since 1993, he has been with the Federal University of Santa Maria, where he is currently a Professor in the Industrial Technical School. He has been with the Electronic Ballast Research Group, Federal University of Santa Maria, as a Researcher. His research interests include electronic ballasts, lamps, dimming systems, power factor correction, fluorescent lamps, and LEDs. Prof. da Silva also serves as a Reviewer for IEEE journals and conferences in the field of power electronics


N. B. Chagas was born in Chapecó, Brazil, in 1990. She received the B.S. degree in electrical engineering from the Federal University of Santa Maria, Santa Maria, Brazil, in 2012. Since 2008, she has been a Researcher in the Electronic Ballast Research Group, Federal University of Santa Maria. Her research interests include the following: intelligent lighting, dc/dc converters, power factor corrections stages, dimming systems, fluorescent lamps, and resonant converters.

M. E. Schlittler was born in Santa Cruz do Sul, Brazil, in 1990. He is currently working toward the Graduation degree in electrical engineering from the Federal University of Santa Maria, Santa Maria, Brazil. He has been with the Electronic Ballast Research Group (GEDRE), the Federal University of Santa Maria, since 2009. His research interests include dc/dc converters, power factor correction stages, dimming systems, high-frequency electronic ballasts, and integration of converters. J. Fraytag was born in Coronel Bicaco, Brazil, in 1990. He is currently working toward the B.S. degree in electrical engineering at the Federal University of Santa Maria, Santa Maria, Brazil, since 2009. He is a Researcher with the Electronic Ballast Research Group (GEDRE), the Federal University of Santa Maria. His research interests include the following: intelligent lighting, dc/dc converters, power factor corrections stages, dimming systems, fluorescent lamps, light-emitting-diode systems, and resonant converters. Mr. Fraytag is a Student Member of the Brazilian Power Electronics Society. T. B. Marchesan (S’03–M’08) was born in Santa Maria, Brazil, in 1980. He received the B.S. (with first class Hons.) and Ph.D. degrees from the Federal University of Santa Maria, Santa Maria, Brazil, in 2003 and 2008, respectively, both in electrical engineering. Since 2000, he has been a Researcher in the Electronic Ballast Research Group, Federal University of Santa Maria. He was an Associate Professor in the Department of Technology, Regional University of the Northwest, Rio Grande do Sul, Brazil, in 2008. From 2009 to 2011, he was a Research and Development Engineer in the Power Transformer Group, WEG Electric Corporation and a Professor at Sinos River valley University, Rio Grande do Sul. Since 2011, he has been a Full Professor at the Federal University of Santa Maria. His research interests include electronic ballasts, high intensity discharge lamps, LEDs, dimming systems, modeling, and simulation of power converters. F. E. Bisogno was born in Santa Maria, Brazil, in 1973. He received the B.S. and M.S. degrees in electrical engineering, in 1999 and 2001, respectively, from the Federal University of Santa Maria, Santa Maria, Brazil, and Dr.-Ing. degree in electrical engineering from Technische Universität Chemnitz, Chemnitz, Germany, in 2006. From 2003 to 2009, he was a Researcher Engineer at Fraunhofer Institute Autonomous Intelligent Systems, Institute for Autonomous Intelligent Systems, and Institute for Reliability and Microintegration. Since 2009 he has been a Professor in the Department of Electric Energy Process, Federal University of Santa Maria. His research interests include resonant converters, electronic ballast, self-oscillating systems, power supply miniaturization, piezoelectric transformers, sensitivity analysis, lighting systems, fluorescent lamp model, and LED lighting systems.


J. Marcos Alonso (S’94–M’98–SM’03) received the M.Sc. and Ph.D. degrees both in electrical engineering from the University of Oviedo, Oviedo, Spain, in 1990 and 1994, respectively. In 2007, he joined the Department of Electrical Engineering, University of Oviedo, where he is a Full Professor. He is a coauthor of more than 300 journal and conference publications. His research interests include electronic ballasts, LED power supplies, power factor correction, and switching converters in general. He was a Supervisor of seven Ph.D. thesis and he is the holder of seven Spanish patents. Dr. Alonso has been awarded with the Early Career Award of the IEEE Industrial Electronics Society in 2006. He also holds three IEEE paper awards. Since October 2002, he has been serving as an Associate Editor of the IEEE TRANSACTIONS ON POWER ELECTRONICS. He has been a Co-Guest Editor of two special issues in lighting applications published in the IEEE TRANSACTIONS ON POWER ELECTRONICS (2007) and IEEE TRANSACTIONS ON INDUSTRIAL ELECTRONICS (2012) and has co-organized several conference special sessions. He is also a member of the European Power Electronics Association and he belongs to the International Steering Committee of the European Conference on Power Electronics and Applications

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R. N. do Prado (M’00) was born in Itapiranga, Brazil, in 1961. He received the B.Sc. degree from the Federal University of Santa Maria, Santa Maria, Brazil, in 1984, and the M.Sc. and Ph.D. degrees from the Federal University of Santa Catarina, Santa Catarina, Brazil, in 1987 and 1993, respectively, all in electrical engineering. From 1987 to 1992, he was with Federal University of Minas Gerais, Minas Gerais, Brazil. Since 1993, he has been with the Federal University of Santa Maria, where he is currently an Associate Professor in the Department of Electrical Energy Processing. In 1997, he founded the Electronic Ballast Research Group. From 2005 to 2006, he was with the Fraunhofer Institute, Germany, as a Postdoctoral Research Scholar. He has authored more than 200 technical papers published in conference proceedings and magazines. His research directions include high frequency, fluorescent and high-pressure lamps, dimming systems, luminous efficiency, electronic ballasts, LED as a source light and power-factor correction. Dr. Prado is a founding member of the Brazilian Power Electronics Society, member of the Brazilian Automatic Control Society, and several IEEE societies. He is a Reviewer of the Brazilian Power Electronics Society, Brazilian Automatic Control Society, and several IEEE societies.