Michael Gulko

Current-sourcing push-pull parallel-resonance inverter (CS-PPRI): theory and application as a fluorescent lamp driver

A novel topology, current-sourcing push-pull parallel-resonance inverter (CS-PPRI), is investigated theoretically and experimentally. The proposed power stage is built around a current fed push-pull inverter. The main features of the proposed inverter are a load-independent output current and zero voltage switching (ZVS). It is suggested that the proposed CS-PPRI is a viable alternative for realizing electronic ballasts for low and high intensity discharge lamps.<<ETX>>

A MHz electronic ballast for automotive-type HID lamps

The compatibility of the current sourcing push pull resonant inverter (CS-PPRI) with the driving requirements of HID lamps designated for automotive headlight applications was investigated theoretically, by simulation and experimentally. The study reveals that a based ballast (CS-PPRI) complies with the automotive requirement of very fast warm up. The experimental ballast was run under zero voltage switching (ZVS) at a nominal switching frequency of 1.29 MHz while the pre-ignition switching frequency was 124 kHz. Warm up time to 80% after cold ignition was about 10 seconds.

Inductor-controlled current-sourcing resonant inverter and its application as a high pressure discharge lamp driver

The practicality of designing a fixed-frequency resonant inverter that is controlled by a variable inductor was investigated theoretically and experimentally. The proposed approach was studied by considering the design of current source resonant inverter. The theoretical analysis yielded closed form (albeit implicit) relationships between the inductance and the transfer function of the inverter. Excellent agreement was found between model predictions and experimental results. An experimental inverter was designed and tested as an electronic ballast for a discharge lamp (metal halide lamp). The inverter was operated at 200 kHz and included ignition circuitry and dimming capability.<<ETX>>

Current-sourcing push-pull parallel-resonance inverter (CS-PPRI): theory and application as a discharge lamp driver

A novel topology, current-sourcing push-pull parallel-resonance inverter (CS-PPRI) was investigated theoretically and experimentally. The proposed power stage is built around a current fed push-pull inverter. The main features of the proposed inverter are: a load independent output current and zero voltage switching (ZVS). It is suggested that the proposed CS-PPRI is a viable alternative for realizing electronic ballasts for low and high-intensity discharge lamps. >

Design and performance of an electronic ballast for high-pressure sodium (HPS) lamps

Design requirement and performance evaluation were carried out on an experimental electronic ballast for High Pressure Sodium (HPS) lamp. The ballast included a high voltage ignitor and dimming capability. It was used to drive and examine the high frequency characteristics of commercial HPS lamp (NAV-T 150 W (SON-T), OSRAM). The experimental results reveal that for the frequency range of this study (27 to 75 kHz), the lamp is free of the acoustic resonance problem. It was also found that for the present experimental conditions, the lamp is purely resistive and that the resistance is practically independent of the power level and operating frequency. The lamp exhibited stable operation over a very large dimming range, down to about 7% of nominal power. The 2.8 kV ignition pulse was found to be sufficient for both cold and hot start up under the proposed operating conditions.

The simplest electronic ballast for HID lamps

The resonant forward-flyback (RFF) inverter is presented, analyzed theoretically and tested experimentally. It is shown that the inverter can be designed to operate under zero voltage switching (ZVS) conditions and that it acts as a current source, features that are highly compatible with HID lamp ballasting. The design guidelines and the detailed analytical expressions developed in this study were verified by computer simulation and hardware implementation. The experimental results of the study demonstrate that the arc of small 35 W and 70 W metal halide discharge lamps can be stabilized by the proposed RFF ballast when operated in the 300 kHz to 400 kHz switching frequency range and applying about 20% FM modulation. Considering the fact that the proposed ballast includes only one switching device, one magnetic component and one resonant capacitor, the RFF inverter is most likely the simplest ballast topology possible.

A resonant DC-DC transformer

The characteristics of a push-pull parallel resonant converter (PPRC) when operated as a DC-DC transformer were investigated theoretically and experimentally. In the DC-DC transformer region, the voltage transfer ratio of the PPRC was found to be practically constant and independent of the input voltage and load. In this mode, all the switching elements operate in the zero voltage switching (ZVS) condition. Another important feature of the proposed DC-DC transformer is the ability to drive it by an arbitrary switching frequency, provided that the latter is lower than the self-oscillating frequency. This permits the synchronization of the converter to a master clock. The analytical expressions for voltage and current stresses, as well as the other key parameters derived, are applied to develop design guidelines for the DC-DC transformer. The proposed topology was tested experimentally on a 100-W unit which was run in the 200-kHz frequency region. >

Current-fed multi-resonant DC-DC converter

A current-fed multi-resonant DC-DC converter is studied theoretically and experimentally. The main features of the proposed converter are inherent protection against a short circuit at the output, and high voltage gain and zero voltage switching over a large range of output voltage. These characteristics make it a viable choice for the implementation of a high voltage capacitor charger.<<ETX>>

Design and performance of an electronic ballast for high pressure sodium (HPS) lamps

Design requirement and performance evaluation were carried out on an experimental electronic ballast for High Pressure Sodium (HPS) lamp. The ballast included a high voltage ignitor and dimming capability. It was used to drive and examine the high frequency characteristics of commercial HPS lamp (NAV-T 150 W (SON-T), OSRAM). The experimental results reveal that for the frequency range of this study (27 to 75 kHz), the lamp is free of the acoustic resonance problem. It was also found that for the present experimental conditions, the lamp is purely resistive and that the resistance is practically independent of the power level and operating frequency. The lamp exhibited stable operation over a very large dimming range, down to about 7% of nominal power. The 2.8 kV ignition pulse was found to be sufficient for both cold and hot start up under the proposed operating conditions.