Ana Vladan Stankovic

A New Control Method for Input–Output Harmonic Elimination of the PWM Boost-Type Rectifier Under Extreme Unbalanced Operating Conditions

Under severe fault conditions in the distribution system, not only input voltages but also input impedances must be considered as unbalanced. This paper presents a new control method for input-output harmonic elimination of the pulsewidth-modulation (PWM) boost-type rectifier under conditions of both unbalanced input voltages and unbalanced input impedances. The range of imbalance in both input voltages and input impedances, for which the proposed method is valid, is analyzed in detail. An analytical approach for complete harmonic elimination shows that PWM boost-type rectifier can operate at unity power factor under extremely unbalanced operating conditions resulting in a smooth (constant) power flow from AC to DC side. Based on the analyses in open-loop configuration, a feedforward control method is proposed. Elimination of harmonics at AC and DC side of the converter affects the cost of DC link capacitor and AC side filter. The proposed method is very useful when the PWM boost-type rectifier is subject to extreme imbalance due to severe fault conditions in the power system. In addition, by using the proposed method, the PWM boost-type rectifier can be operated from the single-phase supply in cases where three-phase source is not available. Simulation results show excellent response and stable operation of the PWM boost-type rectifier under the proposed control algorithm. Experimental and simulation results are in excellent agreement.

A generalized control method for input-output harmonic elimination for the PWM boost rectifier under simultaneous unbalanced input voltages and input impedances

Under severe fault conditions in the distribution system, not only input voltages, but also input impedances must be considered as unbalanced. This paper presents a new control method for input-output harmonic elimination of the PWM boost type rectifier under conditions of both unbalanced input voltages and unbalanced input impedances. The range of unbalance in both input voltages and input impedances, for which the proposed method is valid, is analyzed in detail. An analytical approach for complete harmonic elimination shows that PWM boost type rectifier can operate at unity power factor under extreme unbalanced operating conditions resulting in a smooth (constant) power flow from AC to DC side. Based on the analyses in the open loop configuration, a feed-forward control method is proposed. Elimination of harmonics at AC and DC side of the converter affects the cost of DC link capacitor and AC side filter. The proposed method is very useful when PWM boost type rectifier is subject to extreme unbalance due to severe fault conditions in the power system. In addition, by using the proposed method, the PWM boost type rectifier can be operated from the single-phase supply in cases where three-phase source is not available. Simulation results show excellent response and stable operation of the PWM boost type rectifier under the proposed control algorithm.

Modified Synchronous-Buck Converter for a Dimmable HID Electronic Ballast

In this paper, a simple and effective way of increasing the efficiency of a three-stage low-frequency dimmable high-intensity-discharge (HID) electronic ballast is proposed. To increase the efficiency at all dimming levels, a modified synchronous-buck converter operating in a new critical conduction mode is presented. The proposed modified topology of the synchronous-buck converter operates in a soft-switching mode and therefore significantly increases the efficiency of the three-stage low-frequency HID electronic ballast at all dimming levels. Analytical and experimental results for a dimmable 400-W HID lamp are presented.

A novel control method for input output harmonic elimination of the PWM boost type rectifier under unbalanced operating conditions

This paper presents a new control strategy to improve the performance of the PWM boost type rectifier when operating under an unbalanced supply. An analytical solution for harmonic elimination under unbalanced input voltages is obtained resulting in a smooth (constant) power flow from AC to DC side in spite of the unbalanced voltage condition. Based on the analysis of the open loop configuration, a closed loop control solution is proposed. Simulation results show excellent response and stable operation of the new rectifier control algorithm. A laboratory prototype has been designed to verify the discussions and analyses done in this paper. Theoretical and experimental results show excellent agreement. Elimination of the possibility of low order AC and DC side harmonics due to unbalance is expected to materially affect the cost of DC link capacitor and AC side filter. The proposed method will be particularly useful in applications where the large second harmonic at the DC link may have a severe impact on system stability of multiply connected converters on a common link.

Design, Analysis and Optimization of a Universal Power Factor Correction Circuit for Linear Fluorescent Lamps

In this paper the analysis and optimization of a universal high power factor correction circuit for linear fluorescent lamps is presented. The design and analysis criteria for the converter include a universal voltage input, 120 to 277 V AC with power handling capability from no load to 110 watts. In addition a new PSPICE model for universal power factor correction circuit operating in the critical conduction mode has been developed. Simulation and analytical results have been validated against actual laboratory measurements.

Modeling and Design of L-Complementary Self-Oscillating Class D Inverter With Output Voltage Clamping

New mathematical models of L-complementary self-oscillating class D inverter with output voltage clamping in the steady state and during starting are proposed in this paper. The proposed models are very useful for predicting the converter operation and optimizing the circuit design. Experimental results for a 42-W spiral compact fluorescent lamp electronic ballast are presented to validate the analysis.

A universal programmed start dimming ballast platform

In this paper, a novel universal programmed start dimming ballast platform for fluorescent lamps is proposed. The proposed platform consists of an independent PWM type filament heating control circuit for filaments preheat and filament heating in dimming condition. Mathematical analysis of the proposed method is discussed in the paper. Experimental results of T8 32watt and T5 28watt lamps are presented to validate the proposed method.

Modeling and design of L-Complementary self-oscillating class D inverter with output voltage clamping

New mathematical models of L-complementary self-oscillating class D inverter with output voltage clamping in the steady state and during starting are proposed in this paper. The proposed models are very useful for predicting the converter operation and optimizing the circuit design. Experimental results for a 42-W spiral compact fluorescent lamp electronic ballast are presented to validate the analysis.

Modeling and design of L-Complementary Self-Oscillating Class D inverter with output voltage clamping during starting

In this paper, a detailed time domain analysis and accurate time domain model of L-Complementary self-oscillating class D inverter with output voltage clamping during starting is proposed. Experimental results for 42watt spiral CFL electronic ballast are presented to validate the analysis.

New model of L-Complementary self-oscillating class D inverter with output voltage clamping

In this paper, a detailed time domain analysis and accurate time domain model of L-Complementary self-oscillating class D inverter with output voltage clamping in the steady state is proposed. The proposed model is very useful for predicting the converter voltages and currents as well as for optimizing the circuit design. Experimental results for 42watt spiral CFL electronic ballast are presented to validate the analysis.