Abstract: An inverter device (1), including a first inverter (10), and a second inverter (20) connected in parallel to the first inverter. Both the first and second inverters (10, 20) are three-level inverters. The first and second inverters (10, 20) generate first and second output voltages (V1, V2) using the voltage (Vc) at the connection point between a first capacitor (C1) and a second capacitor (C2) connected in series and evenly allocating a power supply voltage (Vin). A control circuit (40) duty-controls the second inverter at high frequency, when the second inverter (20) switches the level of the second output voltage (V2).

Abstract: An electric power supply apparatus, which enables a driving frequency of a switching circuit connected to a primary side of a transformer constant and output of a secondary side variable, comprises a transformer (5), a series circuit of two first switching elements (Q1, Q2) connected between terminals of a direct current power supply (2), an LC resonant circuit connected between both ends of one of the first switch element (Q2) and a primary winding (Np) of the transformer (5), bidirectional switch elements (Q3, Q4) connected to secondary windings (Ns1, Ns2) of the transformer (5) and having a rectification function and a phase control function, and a control circuit for inputting gate driving signals having a phase difference into the first switch elements (Q1, Q2) and the second switch elements (Q3, Q4).

Abstract: A DC power supply system includes a DC power supply and a secondary battery for backing up the DC power supply. When a voltage of the DC power supply is lower than a voltage of the secondary battery, the DC power system adds an extra voltage to the voltage of the DC power supply to provide an input voltage to the secondary battery higher than the voltage of the secondary battery by using an electric power of the secondary battery, and the secondary battery is charged.

Abstract: A DC/DC converter has DC input terminals to which a DC power is inputted, a transformer, and a bidirectional switching device on the primary side of the transformer.

Abstract: A DC power distribution system is equipped with a storage device having a first storage battery, which discharges to electrical apparatuses only during power failure, and a second storage battery, which discharges to electrical apparatuses when service is not interrupted. The electricity storage device and electrical apparatuses are supplied with DC power from a power generation device which generates electricity using natural energy, and DC power which has been converted from AC power supplied from a commercial power source. When the power supply from the electricity generation device and the commercial power source is interrupted, the first storage battery discharges power to the electrical apparatuses.

Abstract: A physical activity measuring system analyzes analyzing body motions of a user to accurately determine the exercise intensity. The system includes a portable device which is adapted to be carried by the user and is equipped with a body sensor and an indicator for indication of the exercise intensity. The body sensor senses the user's body motions to give corresponding motion strength. The portable device has a processor which constitutes an exercise calculator which has a predetermined relationship between a default standard deviation of the motion strength and an exercise intensity scale. The exercise intensity calculator collects a time series data of the motion strengths within a predetermined first time frame, obtains a standard deviation of thus collected motion strengths, and converting the standard deviation into an instant exercise intensity within the intensity scale in accordance with the predetermined relationship.

Abstract: An activity intensity measurement device comprises an accelerator, a sampling means, a representative value calculation means, a sampling means, a representative value calculation means, and an activity intensity determination means. The sampling means is configured to sample discrete values from the detected acceleration. The representative value calculation means is configured to calculate the representative value from the discrete values of a plurality of the acceleration. The activity intensity determination means is configured to determine the activity intensity on the basis of the calculated representative value. The representative value calculation means is configured to calculate the representative value at intervals of unit period corresponding to the user's particular activity. Consequently, all of the user's particular activity is reflected to the representative value. Therefore, this activity intensity measurement device is configured to calculate exact activity intensity.

Abstract: A physical activity measuring system analyzes analyzing body motions of a user to accurately determine the exercise intensity. The system includes a portable device which is adapted to be carried by the user and is equipped with a body sensor and an indicator for indication of the exercise intensity. The body sensor senses the user's body motions to give corresponding motion strength. The portable device has a processor which constitutes an exercise calculator which has a predetermined relationship between a default standard deviation of the motion strength and an exercise intensity scale. The exercise intensity calculator collects a time series data of the motion strengths within a predetermined first time frame, obtains a standard deviation of thus collected motion strengths, and converting the standard deviation into an instant exercise intensity within the intensity scale in accordance with the predetermined relationship.

Abstract: A ballast for a discharge lamp capable of reliably and successfully detecting the end of the lamp life and ceasing the ballast immediately upon detection of the lamp's life end. The ballast includes a power supply providing from a power source a variable power to the lamp, and a power controller controlling the power supply to apply a high voltage for igniting the lamp and subsequently apply a predetermined power for operating the lamp. A lamp life detector is included in the ballast to detect whether or not the lamp comes to a lamp's life end. Also included in the ballast is a supervisor which issues, upon detection of the lamp's life end, a disable signal prohibiting the power supply from lighting the discharge lamp.

Abstract: A method and a ballast for starting a discharge lamp capable of making a rapid start while restraining the overshoot of the light output. The ballast can separately give the initial start time period of applying a maximum power rating to the lamp and the subsequent curve along which the power decreases to a normal power rating of the lamp. A power is varied along a particular run-up curve so as to apply the maximum power rating and subsequently apply the power decreasing to the normal power rating. The run-up curve is derived from a reference curve having a power level decreasing with time. The reference curve has a maximum value above the maximum power rating, and has an inflection point near the maximum power rating to define first and second reference curves above and below the inflection point, respectively. The first reference curve has a first average slope for a first time period from a point of the maximum value to the inflection point.