Abstract: A power storage system is provided with charge switches, discharge switches, a bidirectional DC/DC converter and a power storage system controller connecting all the battery packs to an external circuit to achieve parallel charge and discharge, and the power storage system starts the charge by setting a rated charge current value per one battery pack to Iset and setting the rated charge current value Iset as an initial value of a charge current command value Iref(1), thereafter monitor the charge current of each of the battery packs after elapse of a predetermined time so as to subtract its maximum value Ibmax(1) from the charge current command value Iref(1), and add the rated charge current value Iset to result of subtraction Ierr (Iref(1)?Ibmax(1)) so as to set as a new charge current command value Iref(2) and carry out pre-charge in such a manner as to carry on the charge.

Abstract: A power storage system is provided with charge switches, discharge switches, a bidirectional DC/DC converter and a power storage system controller connecting all the battery packs to an external circuit to achieve parallel charge and discharge, and the power storage system starts the charge by setting a rated charge current value per one battery pack to Iset and setting the rated charge current value Iset as an initial value of a charge current command value Iref(1), thereafter monitor the charge current of each of the battery packs after elapse of a predetermined time so as to subtract its maximum value Ibmax(1) from the charge current command value Iref(1), and add the rated charge current value Iset to result of subtraction Ierr (Iref(1)?Ibmax(1)) so as to set as a new charge current command value Iref(2) and carry out pre-charge in such a manner as to carry on the charge.

Abstract: Proposed are a power factor correction device and its control method capable of obtaining a stable output as the output of a power supply unit while simplifying and miniaturizing the configuration. In the power factor correction device and the control method thereof including a coil and a switching element, and a control unit for controlling ON/OFF of the switching element, provided are an input voltage detection unit for detecting an input voltage of the power factor correction device, an output voltage detection unit for detecting an output voltage, and a coil current detection unit for detecting a coil current that is generated in the coil pursuant to the ON/OFF operation of the switching element.

Abstract: Proposed are a power factor correction device and its control method capable of obtaining a stable output as the output of a power supply unit while simplifying and miniaturizing the configuration. In the power factor correction device and the control method thereof including a coil and a switching element, and a control unit for controlling ON/OFF of the switching element, provided are an input voltage detection unit for detecting an input voltage of the power factor correction device, an output voltage detection unit for detecting an output voltage, and a coil current detection unit for detecting a coil current that is generated in the coil pursuant to the ON/OFF operation of the switching element.

Abstract: In a digital controlled power supply including a digital controller for generating a PWM signal which is used to turn on and off a switching element to obtain an output voltage for a load based on an input voltage, the digital controller includes an AD converter for receiving an analog output current from the power supply and converting the current into a digital value to produce a digital output current value, an arithmetic processing unit for conducting an arithmetic operation of a pulse width for each period of a sampling frequency of the AD converter or a frequency of carrier wave as a criterion to obtain the PWM signal, and a frequency controller for variably controlling the frequency of carrier wave and the sampling frequency on the basis of the digital output current value from the AD converter.

Abstract: To provide a smaller and more efficient switching power supply, the switching power supply includes: a high frequency transformer; a primary side switching circuit adapted to switch a current flowing through a primary winding of the high frequency transformer to thereby generate predetermined voltages in a secondary winding and an auxiliary winding of the high frequency transformer; a secondary side rectifier adapted to rectify a voltage generated in the secondary winding to supply the rectified voltage to a load; a charging circuit adapted to rectify a current flowing through the auxiliary winding and to switch the rectified current to thereby charge a secondary battery at a constant current; and a switch, provided between the secondary battery and the load, which supplies, when the voltage supplied to the load is interrupted, the voltage of the secondary battery to the load without going through the high frequency transformer.

Abstract: A DC backup power supply system having a plurality of loads to which AC from a commercial power source is supplied, and DC power storage means for supplying DC power to the plurality of the loads at the time of a power outage of the commercial power source, said DC backup power supply system including: a control circuit having a first DC backup output for supplying a power from the DC power storage means to the plurality of the loads, including a specific load, only during the power outage of the commercial power source, and a second DC backup output for continuously supplying a power from the DC power storage means to the specific load regardless of the power outage of the commercial power source or sound operation thereof, the control circuit supplying the respective powers from the same DC power storage means to the first and second DC backup outputs.

Abstract: A bidirectional DC-DC converter 10 has smoothing capacitors Cs1 and Cs2, a smoothing reactor Ls, resonant reactors Lr1 and Lr2, and a resonant capacitor Cr, as well as insulated gate bipolar transistors (IGBTs) Q1, Q2, and Q3 to which buffer capacitors C1, C2, and C3 are connected in parallel and diodes D1, D2, and D3 are connected in a back-to-back configuration. After part of the energy stored in the smoothing reactor Ls and/or resonant reactors Lr1 and Lr2 draws charges in the buffer capacitor C3 and is stored in the resonant capacitor Cr, the energy is stored in the resonant reactors Lr1 and Lr2. The energy is used to draw charges in the buffer capacitors C1 and C2, achieving soft switching of IGBTs Q1, Q2, and Q3.

Abstract: An object of the invention is to provide a small and low-cost switching power supply unit with a backup function in which a proper circuit construction can be selected by simple method when it is necessary to compensate for the instantaneous drop or power failure and a disk array system having the switching power supply unit. To accomplish the object, a backup unit which can insert and pull out its hot line into a switching power supply unit casing and has a secondary battery and its state monitoring/control unit is built in the unit, and proper charge/discharge management of the secondary battery can be made. When the backup unit is unnecessary, a backup unit formed by a plurality of capacitors whose hot lines can be similarly inserted and pulled out can be built in an enclosing space of the backup unit.

Abstract: A backup power supply is so constructed that it is provided with multiple DC backup power supplies 111 to 11N, each containing nickel-metal hydride battery, stored upright on the bottom of the disk array unit 100; cooled by cooling air through the vents 1011 for ventilation from the bottom to the top; and connected with the output of the AC/DC converters 121, 122 with the backboard 151. Very compact disk array unit with an uninterruptible power supplying function can be realized.

Abstract: In a digital controlled power supply including a digital controller for generating a PWM signal which is used to turn on and off a switching element to obtain an output voltage for a load based on an input voltage, the digital controller includes an AD converter for receiving an analog output current from the power supply and converting the current into a digital value to produce a digital output current value, an arithmetic processing unit for conducting an arithmetic operation of a pulse width for each period of a sampling frequency of the AD converter or a frequency of carrier wave as a criterion to obtain the PWM signal, and a frequency controller for variably controlling the frequency of carrier wave and the sampling frequency on the basis of the digital output current value from the AD converter.

Abstract: A DC backup power supply system having a battery a charge-discharge circuit for charging and discharging a power between the battery and a DC line and a control circuit for controlling the charge-discharge circuit, wherein the battery has a number of battery cells and cylindrical portions of the battery cells are laid on an approximately horizontal plane.

Abstract: A bidirectional DC-DC converter 10 has smoothing capacitors Cs1 and Cs2, a smoothing reactor Ls, resonant reactors Lr1 and Lr2, and a resonant capacitor Cr, as well as insulated gate bipolar transistors (IGBTs) Q1, Q2, and Q3 to which buffer capacitors C1, C2, and C3 are connected in parallel and diodes D1, D2, and D3 are connected in a back-to-back configuration. After part of the energy stored in the smoothing reactor Ls and/or resonant reactors Lr1 and Lr2 draws charges in the buffer capacitor C3 and is stored in the resonant capacitor Cr, the energy is stored in the resonant reactors Lr1 and Lr2. The energy is used to draw charges in the buffer capacitors C1 and C2, achieving soft switching of IGBTs Q1, Q2, and Q3.

Abstract: A DC backup power supply system having a plurality of loads to which AC from a commercial power source is supplied, and DC power storage means for supplying DC power to the plurality of the loads at the time of a power outage of the commercial power source, said DC backup power supply system including: a control circuit having a first DC backup output for supplying a power from the DC power storage means to the plurality of the loads, including a specific load, only during the power outage of the commercial power source, and a second DC backup output for continuously supplying a power from the DC power storage means to the specific load regardless of the power outage of the commercial power source or sound operation thereof, the control circuit supplying the respective powers from the same DC power storage means to the first and second DC backup outputs.

Abstract: An uninterruptible power system for inputting an AC power, converting the AC power into a desired power, supplying the desired power to a load, and upon occurrence of an AC failure, converting a DC power from energy accumulation means into the desired power and supplying the desired power to the load, wherein the DC power from said energy accumulation means is passed through two serially connected boost means, and thereafter the power is converted into the desired power to be supplied to the load, wherein first boost means of the two serially connected boost means, which is nearer to the energy accumulation means, raises the DC electric power from said energy accumulation means to supply second boost means of the two serially connected boost means when supply of electric power is interrupted, and lowers inputted electric power for charging the electric accumulation means during an ordinary operation.

Abstract: In the case where there coexist general loads requiring backup only for a short duration and a specific load requiring backup for a longer duration, uninterruptible power with higher reliability is supplied to the specific load with the adoption of a simple configuration. A DC backup power supply system comprises an AC/DC converter for normally supplying DC power to loads in while (the general loads and the specific load, included), and a control circuit for supplying DC output backing up the loads in whole for relatively short time only from a battery at the time of a power outage, while supplying DC output backing up the specific load, such as a cache memory and so forth, for relatively long time. Thus, it is possible to implement an uninterruptible power supply system small in size and low in cost, provided with a function for proper use depending on a prevailing situation.

Abstract: To provide a smaller and more efficient switching power supply 10.

Abstract: A reliable uninterruptible DC power supply device. The DC backup power supply device includes an AC/DC converter, a DC/DC converter, voltage step-up/down choppers and a battery connected to a DC path of a main circuit connected with a load via a switch, and a microcomputer. In the device, under control of the microcomputer, the voltage step-up/down choppers are first operated under a condition that the MOS FET was turned OFF for self diagnosis of the backup power supply device. Next, the switch is turned ON to execute the remaining self diagnosis. The DC backup power supply device can execute its self diagnosis with a reduced likelihood of danger of exerting an adverse effect on the main circuit and also can exhibit a reliable uninterruptible power supply function.

Abstract: An object of the invention is to provide a small and low-cost switching power supply unit with a backup function in which a proper circuit construction can be selected by simple method when it is necessary to compensate for the instantaneous drop or power failure and a disk array system having the switching power supply unit. To accomplish the object, a backup unit which can insert and pull out its hot line into a switching power supply unit casing and has a secondary battery and its state monitoring/control unit is built in the unit, and proper charge/discharge management of the secondary battery can be made. When the backup unit is unnecessary, a backup unit formed by a plurality of capacitors whose hot lines can be similarly inserted and pulled out can be built in an enclosing space of the backup unit.

Abstract: An uninterruptible power system for inputting an AC power, converting the AC power into a desired power, supplying the desired power to a load, and upon occurrence of an AC failure, converting a DC power from energy accumulation means into the desired power and supplying the desired power to the load, wherein the DC power from said energy accumulation means is passed through two serially connected boost means, and thereafter the power is converted into the desired power to be supplied to the load, wherein first boost means of the two serially connected boost means, which is nearer to the energy accumulation means, raises the DC electric power from said energy accumulation means to supply second boost means of the two serially connected boost means when supply of electric power is interrupted, and lowers inputted electric power for charging the electric accumulation means during an ordinary operation.