Abstract: A ballast for a vehicle metal halide lamp is simplified using a DC-AC one-step-boost high frequency ballast system. To satisfy requirements specific to a metal halide lamp, a discharge developing capacitor is installed on a primary side of a transformer in parallel with a DC power supply, ensuring discharge development after a breakdown. To reduce the size and increase the operating voltage of the transformer, a booster circuit and voltage-doubler circuit are installed on the primary side and secondary side of the transformer, respectively. To reduce the size of the transformer and achieve a stable discharge, the ballast frequency is swept within a range between the specified minimum frequency and maximum frequency so that the center frequency is from 80 kHz to 120 kHz, and the same frequency is unsustained for more than 10 msec.

Abstract: A load is connected to a first battery group. The first battery group and a second battery group are connected in series to each other. A bidirectional DC/DC converter for electric power migration between the first battery group and the second battery group is provided.

Abstract: Voltage compensating circuits are connected serially to a power system, including capacitors each having different charging voltages (in relationship of approximately 2k (K=0, 1, 2, . . . ) times the smallest charging voltage value). The voltage compensating circuits convert DC voltages in the capacitors into AC voltages and output the AC voltages, respectively. The voltages of the capacitors are detected as detected values V1 to V3. The detected values V1 to V3 are used as bit signals for a reference value to check a voltage dip amount of the power system with the reference value and to convert the voltage dip amount into a binary signal. A combination is selected from the voltage compensating circuits in accordance with the binary signal so that the sum of output voltages of the selected voltage compensating circuits compensates the voltage dip of the power system.

Abstract: An electric discharge machine in which electric power for working is supplied between an electrode and workpiece by an electric power unit so as to generate electric discharge between the electrode and workpiece and conduct machining on the workpiece, the electric discharge machine having a voltage detector for detecting output voltage V of a DC electric power source of the electric power unit; a current detector for detecting output current I of the DC electric power source of the electric power unit; a calculator for calculating product V·I of V and I; and a controller for controlling output electric power of the electric power unit to be constant on the basis of a difference between a working command signal for giving a predetermined electric power command and V·I. Even when load impedance fluctuates, it is possible to suppress the fluctuation of electric discharge power, so that surface roughness on a machined face of the workpiece can be made uniform.

Abstract: In semiconductor equipment, a switching timing adjuster is provided between insulated gate bipolar transistors and a control signal generator. The switching timing adjuster includes an input decision circuit that decides whether a signal output from the overvoltage protector is a signal that has been output due to a deviation in the switching timing at a turn-off or turn-on time, a signal holding circuit that holds a signal that is output from the input decision circuit, and a pulse formation circuit that forms a corrected switching control signal based on a signal held in the signal holding circuit and a switching control signal from the control signal generator.

Abstract: A power supply apparatus for electric discharge machining is provided with a current loop including a diode, which is supplied with a forward current at the same time a voltage for generating a discharge is output or before it; and a resistor. Supply of forward current to the diode is blocked the moment a discharge is generated. By doing so, a reverse recovery current of the diode is supplied in a gap between an electrode and a workpiece to be machined.

Abstract: Switching elements of self-quenching function are connected in series to constitute a semiconductor switching device. A snubber circuit comprising the first diode, the first capacitor and a non-linear circuit is connected in parallel to the respective semiconductor switching element. In the snubber circuit, the first diode and the first capacitor are connected in series, and the non-linear circuit is connected in parallel to the first capacitor. The non-linear circuit comprises a impedance element, a Zener diode, and a controlling semiconductor element and draws current through the controlling semiconductor element when applied voltage exceeds the Zener voltage of the Zener diode. Said Zener voltage is larger than and has minimum latitude to divided voltage of the semiconductor element under an accident in power system.

Abstract: Self-quenching switching elements are connected in series in a semiconductor switching device. Snubber circuits including a diode, a capacitor, and a non-linear circuit are connected in parallel with the respective semiconductor switching elements. In the snubber circuit, the diode and the capacitor are connected in series, and the non-linear circuit is connected in parallel with the capacitor. The non-linear circuit includes an impedance element, a Zener diode, and a controlling semiconductor element and draws current through the controlling semiconductor element when applied voltage exceeds the Zener voltage of the Zener diode. The Zener voltage is larger than a divided voltage applied to the semiconductor element during a fault in a power system.

Abstract: An electric discharge machining apparatus includes a wire electrode for machining a workpiece, and a first voltage applying unit for applying a voltage pulse. The voltage pulse has a rise time longer than a discharge formative time lag when a rectangular voltage pulse is applied, when a distance between the workpiece and the wire is an average value in machining, and rises to the same voltage as the rectangular voltage pulse.

Abstract: There is provided an electrolysis gas converter, which prevents excessive gas generation and can maintain a constant amount of gas conversion even if outside air conditions such as humidity changes. The converter, which provides DC current to a jointed electrochemical device 8 comprising a solid polymer electrolytic film 3 between an anode 1 and a cathode 2 having a catalytic layer on a base substrate of conductive porous material, comprises means 11 and 17 which provide a fixed current to the jointed electrochemical device 8.

Abstract: Charge accumulated in a capacitor is used to provide a processing current flow between a target and an electrode. When a diode is turned on, a first dc power supply is used to provide the processing current flow between the target and the electrode. In this state, after a lapse of a predetermined time, the current supply using the first dc power supply is stopped, and an induced electromotive voltage, induced by two floating reactors, is used to rapidly drop the processing current flowing between the target and the electrode, while charging the capacitor.

Abstract: In the semiconductor equipment, a switching timing adjuster is provided between each IGBT and the control signal generator. The switching timing adjuster comprise an input decision circuit that decides that a signal output from the overvoltage protector is a signal that has been output due to a deviation in the switching timing at a turn-off or turn-on time, a signal holding circuit that holds a signal that is output from the input decision circuit, and a pulse formation circuit that forms a corrected switching control signal based on a signal held in the signal holding circuit and a switching control signal from the control signal generator.

Abstract: A discharge lamp lighting device comprises a booster circuit 2 for boosting the voltage of a DC power source 1 in response to the ON-OFF operation of a switching element 2c, a startup discharge circuit 9 for performing the startup discharge of a discharge lamp 10 according to the boosted DC voltage, a voltage detection circuit 5 for detecting the boosted DC voltage, a control circuit 7b for outputting the pulse modulated by pulse width modulation to the switching element 2c, and a control circuit 7a for controlling the pulse output from the control circuit 7b to the switching element 2c to intermittently enabling or disabling the passage thereof.

Abstract: A discharge lamp lighting device comprises a booster circuit 2 for boosting the voltage of a DC power source 1 in response to the ON-OFF operation of a switching element 2c, a startup discharge circuit 9 for performing the startup discharge of a discharge lamp 10 according to the boosted DC voltage, a voltage detection circuit 5 for detecting the boosted DC voltage, a control circuit 7b for outputting the pulse modulated by pulse width modulation to the switching element 2c, and a control circuit 7a for controlling the pulse output from the control circuit 7b to the switching element 2c to intermittently enabling or disabling the passage thereof.

Abstract: A plurality of voltage compensation circuits P1-P3, N1-N3 converts DC voltages accumulated in a capacitor 11 having respectively different charging voltages (which is 2K times of the minimum voltage (K=0, 1, 2, . . . )) into AC voltages. The plurality of voltage compensation circuits are connected to the electric power system in series. When the voltage dip occurs in an electric power system, a desired combination is selected from the plurality of voltage compensation circuits P1-P3, N1-N3. The total sum of the output voltage compensates the voltage dipped. At the normal time, the high speed mechanical short circuit switch by-passes the voltage compensation circuits to reduce apparatus loss.

Abstract: A synthetic round pulse generation circuit can output constant currents (i1, i2). By charging a capacitance element (CP) with the constant currents (i1, i2), a ramp pulse (10a) having a rate of voltage change of i1/CP and a ramp pulse (10b) having a rate of voltage change of i2/CP are applied to the capacitance element (CP). A synthetic round pulse (11) consists of the ramp pulse (10a) and the ramp pulse (10b). In the synthetic round pulse (11), the lengths of application time periods (T10a, T10b) are set so that a discharge is started with the ramp pulse (10a). Further, the rate of voltage change (i1/CP) of the ramp pulse (10a) is set to a small value so that the intensity of the discharge at a discharge starting time (t11f) in the application time period (T10a) may be sufficiently weak. When a PDP is driven with the synthetic round pulse, it is thereby possible to reduce an application time of the round waveform.

Abstract: A gas discharge lamp lighting device includes a DC/DC converter for adjusting electric power supplied from a power supply to generate and output a DC voltage, and an FET electrically connected to the DC/DC converter, for converting the DC voltage from the DC/DC converter to an AC voltage to be supplied to a gas discharge lamp. A control unit brings the gas discharge lamp to an electrode heating state in which both electrodes of the gas discharge lamp are heated after supplying the AC voltage to the gas discharge lamp. The control unit controls energy supplied to the gas discharge lamp in the electrode heating state according to a voltage across the gas discharge lamp. The control unit brings the gas discharge lamp to an AC discharging state in which an AC current flows through the gas discharge lamp after the energy has been supplied to the gas discharge lamp.

Abstract: Voltage compensating circuits are connected serially to a power system, including capacitors each having different charging voltages (in relationship of approximately 2k-fold (K=0, 1, 2, . . . ) of the smallest charging voltage value). The voltage compensating circuits convert DC voltages in the capacitors into AC voltages and output the AC voltages respectively. The voltages of the capacitors are detected as detected values V1 to V3. The detected values V1 to V3 are used as bit signals for a reference value to check a voltage dip amount of the power system with the reference value and to A/D convert the voltage dip amount into a binary signal. A desired combination is selected from the voltage compensating circuits in accordance with the binary signal so that the total sum of output voltages of the selected voltage compensating circuits compensates the voltage dip of the power system.

Abstract: It is aimed to perform a gradation display by using a light source array. A pixel having a desired luminance Y can be displayed by changing an emission intensity P of LED light source during one pixel display period C and turning on and off LCD corresponding to the change of the emission intensity P of LED light source.

Abstract: In an electrolytic gas converter for converting atmospheric moisture into ozone gas, oxygen gas or hydrogen gas, the electrolytic gas converter is provided with a unit for making control so that an electric current is supplied to the electrochemical device conjunctive body during a predetermined period of time after the start of the operation of gas conversion, the electric current being larger than that after the predetermined period of time passes. In addition, the control unit controls the current to flow periodically. Further, the electrolytic gas converter is provided with a unit for making control so that a predetermined constant current is supplied to the electrochemical device conjunctive body after the predetermined period of time passes since the operation of gas conversion is started.