Hiroyuki Takagi

Megahertz operation of voltage-fed inverter for HID lamps using distributed constant line

A novel type of solid-state ballast, which operates on the MHz-range frequency, is presented in this paper. A circuit composed of a voltage-fed half-bridge inverter, a distributed constant line, and a parallel LC resonant circuit have been developed for this purpose. The HID (high intensity discharge) lamp is connected to the output terminal of the inverter through the distributed constant line. Here, since the length of the line is adjusted to 1/4 of the propagation wavelength /spl lambda/, the output voltage of the voltage-fed inverter can be converted to a current source in the load side. From experimental results, it was found that the ballast can supply not only high voltage but also constant current for starting the discharge of an HID lamp. Experimental results from a prototype system are used to verify the theoretical procedure.

A high-frequency electronic ballast for HID lamps based on a /spl lambda//4-long distributed constant line

A novel type of solid-state ballast, which operates in the megahertz-range frequency, is presented in this paper. A circuit composed of a voltage-source half-bridge inverter, a distributed constant line and a parallel LC resonant circuit has been developed for this purpose. The high-intensity discharge (HID) lamp is connected to the output terminal of the inverter through the distributed constant line. Here, since the length of the line is adjusted to 1/4 of the propagation wavelength /spl lambda/ (/spl lambda//4 condition), the output voltage of the voltage-source inverter can be converted to a current source on the load side. Therefore, the ballast can supply not only high voltage to the HID lamp for initiating discharge, but also stable current to it during discharge condition. The modification of the proposed circuit is also proposed in order to expand the operating frequency without increasing the undesirable harmonic current. The experimental results from a prototype system verify the theoretical procedure.

High frequency electronic ballast for HID lamps based on /spl lambda//4-long distributed constant line with buck-boost AC-DC converter suitable for half bridge inverter

A novel type of solid-state ballast, which operates in the MHz-range frequency, is presented in this paper. A circuit composed of a buck-boost type AC-DC power converter (rectifier), a voltage-source half-bridge inverter, a distributed constant line and a parallel LC resonant circuit has been developed for use in this new ballast. The HID (high intensity discharge) lamp is connected to the output terminal of the inverter through the distributed constant line. Here, since the length of the line is adjusted to 1/4 of the propagation wavelength /spl lambda/ (/spl lambda//4 condition), the output voltage of the voltage-source inverter can be converted to a current source at the load side. Therefore, the ballast can not only supply the HID lamp with high voltage to initiate discharge, but can also supply with stable current during lamp running condition. Further, the proposed ballast enables the HID lamps to control luminous intensity with the novel buck-boost AC-DC power converter and the discharge current feedback control. The experimental results from a prototype system verify the theory underlying this research.