Panasonic Corporation

Panasonic Intellectual Property Management Co., Ltd.

Go Yamada

Syunsuke Ono

Masahiro Yamamoto

Minoru Ozasa

Keiji Akamatsu

Fumito Kusama

Takaaki Norisada

Tsuyoshi Ichibakase

Masaru Ikeda

Makoto Ozone

Yutaka Kamon

A control unit controls an inverter circuit such that a positive voltage and a negative voltage are alternately applied to a primary winding. The control unit controls a cycloconverter so as to allow no power to be transmitted between the cycloconverter and the inverter circuit in a first period including an inversion period during which a voltage of the primary winding has its polarity inverted. The control unit also controls the cycloconverter so as to allow power to be transmitted either in a first direction from the cycloconverter toward the inverter circuit, or in a second direction opposite from the first direction, in a second period different from the first period.

Regenerative power conversion system with inverter and converter

A power conversion device includes first and second terminals connected to a DC power source, third and fourth terminals connected to a commercial power system or a load, a transformer including a primary winding having seventh and eighth terminals and a secondary winding having fifth and sixth terminals, an inverter circuit connected between the first and second terminals and the seventh and eighth terminals, a converter circuit connected between the fifth and sixth terminals and the third and fourth terminals, a diode bridge including first and second AC input terminals connected to the fifth and sixth terminals, respectively, and first and second DC output terminals, a first capacitor connected between the first and second DC output terminals, and a first resistor connected in parallel with the first capacitor between the first and second DC output terminals.

Power conversion device including primary inverter, transformer, secondary converter

A power converter includes first to fourth terminals, a transformer including primary and secondary windings, an inverter connected between the first and second terminals and the primary winding, a converter connected between fifth and sixth terminals, and a controller. The converter includes first to eighth switch circuits each including a diode and a switch connected in parallel. When a voltage between the fifth and sixth terminals has first polarity, the controller controls the first switch circuit to be in on-state during a first on-period and controls the fifth switch circuit to be in on-state during a second on-period completely including the first on-period. When the voltage between the fifth and sixth terminals has second polarity, the controller controls the second switch circuit to be in on-state during a third on-period and controls the sixth switch circuit to be in on-state during a fourth on-period completely including the third on-period.

Power conversion device including primary inverter, transformer, secondary converter, and controller

A projection-type image display apparatus includes a high pressure discharge lamp, which utilizes the halogen cycle, and a lamp lighting apparatus that controls lighting of the high pressure discharge lamp. The lamp lighting apparatus performs lamp refresh processing to improve a lamp property. The lamp refresh processing involves performing low power lighting of the high pressure discharge lamp by changing the lighting power of the high pressure discharge lamp to a value that is lower than the rated power, and thereafter performing high power lighting of the high pressure discharge lamp by changing the lighting power to a value that is higher than the lighting power during the low power lighting.

Projection-type image display apparatus, lighting apparatus and lighting method realizing an extended lifetime

Constant current control is performed after the completion of starting operation of a high-pressure mercury-vapor lampand then lighting is shifted to constant power lighting. Except during a modulation forbidden period as a certain period from the completion of the starting operation, the frequency of an alternating current is subjected to frequency modulation control for being modulated to at least a first frequency and a second frequency having higher audibility than the first frequency. During the modulation forbidden period defined as a period from the completion of the starting operation until a predetermined time before lighting is shifted to constant power lighting, from the completion of the starting operation until lighting is shifted to constant power lighting, or from the completion of the starting operation until a predetermined time after lighting has been shifted to constant power lighting, the frequency modulation control is not performed and an alternating current with a third frequency lower than the second frequency is supplied. The quietness can be increased without adversely affecting the frequency modulation control on an alternating current for properly growing and maintaining protrusions of electrodes.

High-pressure discharge lamp lighting device with current control, high-pressure discharge lamp device using same, projector using said high-pressure discharge lamp device, and high-pressure discharge lamp lighting method with current control

A high-pressure discharge lamp system has a high-pressure mercury lampand a lighting circuitthat operates the lamp. The lampincludes an envelope having a light emitting parthaving a first and a second electrodearranged therein and a first and a second sealing partoppositely extending from the light emitting part, and a conductorelectrically connected to the second electrode. Particularly a portion of the conductoris at least in contact with or in closest proximity to the outer surface of the first sealing partsubstantially at a single point in an area corresponding to a first metal foilconnected to the first electrode. The circuitactivates the lampby placing high-frequency voltage at a predetermined frequency within a range of 10 [kHz]-10 [MHz], inclusive, between the electrodes

High-pressure discharge lamp system and projector using the same

After startup, a lighting method for a high-pressure discharge lamp is to light the lamp at a rated frequency without switching the frequency for 120 seconds (S, S), and thereafter to switch from the rated frequency to a more audible frequency in accordance with a change in voltage value (Sto S).

Lighting method for a high-pressure discharge lamp, lighting circuit for a high-pressure discharge lamp, high-pressure discharge lamp apparatus, and projector-type image display apparatus

An object of the present invention is to provide a lighting method and the like that can prevent a lamp temperature of each individual high-pressure mercury lamp from being beyond a proper temperature range of a halogen cycle. The lighting method maintains a discharge of the high-pressure mercury lamp that has a function of the halogen cycle. The control is performed as follows. From when the high-pressure mercury lamp is lighted up to when a lamp voltage Vla reaches a first voltage value V, a constant current control is performed. When the lamp voltage Vla reaches the first voltage value V, the constant current control is switched to a constant power control which is performed at a first power value W. While the discharge of the lamp is maintained, when the lamp voltage Vla reaches a voltage value (second voltage value V) at which a state of the halogen cycle deviates from a proper state, the constant power control is performed by reducing the first power value Wto a second power value W

Method of lighting high pressure mercury lamp, lighting device for the same, lamp system and projection display unit

Provided is a method for lighting a high pressure discharge lamp capable of increasing the life thereof. The lighting method is as follows. When the time elapse after lighting up the discharge lamp is within a predetermined condition (e.g. 5 minutes or less), constant current control is performed if the lamp voltage is lower than switching voltage (here, a first voltage value V) and constant power control is performed to maintain the lamp power at a power value Wif the lamp voltage is equal to or above the switching voltage. After the predetermined condition (5 minutes) is exceeded, the constant power control is performed by lowering the value of the switching voltage from the first voltage value Vto the second voltage value V. If the lamp voltage is equal to or above the switching voltage lowered, the lamp power is maintained at power value W

Growing community of inventors

Osaka, Japan

Go Yamada