JP2008005565A - Power supply device with uninterruptible power supply function - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To achieve a highly reliable high efficiency power supply device with an uninterruptible power supply (UPS) function in which the capacity of backup power supply is increased. <P>SOLUTION: Main circuit (1-5) has a switching type power supply arrangement and a super capacitor SC is employed as a backup power supply. Charge/discharge circuit (CON, SW) of the super capacitor is separated from the main circuit and the output from the backup power supply device is attached at the input wiring portion of a switching transformer (T1) of the main circuit. An arrangement for stopping the backup power supply device when the main circuit is normal, and an arrangement for performing self diagnosis of the backup power supply device during idle period are also included. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a power supply device with an uninterruptible power supply function (UPS) that supplies power from a backup power supply when an abnormality occurs in a main circuit.

  With recent increases in the capacity of software including the OS and the memory of computer devices, an increasing number of devices require shutdown processing when the system is stopped. In this case, there is no problem in the normal system stop process, but in the event of an unexpected power failure, not only important data may be damaged, but it may also become impossible to restart.

In order to solve such a problem, it is common to use an uninterruptible power supply such as UPS as a power supply for a computer apparatus. There is also a computer device equipped with a switching power supply having an uninterruptible power supply (UPS) function inside the apparatus. When using a switching power supply with an uninterruptible power supply (UPS) function inside the device, it is usually converted to DC24V or DC12V by an AC-DC conversion circuit, and the voltage and a battery (backup power supply) such as a lead seal battery are used. In general, an output voltage such as DC 12 V or DC 5 V is generated by a DC-DC conversion circuit (see, for example, Patent Document 1).
JP 2000-014043 A

  When the computer device is connected to an external uninterruptible power supply (UPS) and used, the uninterruptible power supply is converted from AC to DC in the inverter system, and after adding this and a battery, convert it to AC again. AC power is supplied to the computer device. And various DC outputs are supplied to the circuit device in a computer apparatus by the AC-DC conversion circuit with the power supply of a computer apparatus. In this case, since the voltage conversion is performed three times, AC → DC → AC → DC (inside the computer), the efficiency is very low, and it is necessary to install the uninterruptible power supply outside the computer device. There is a fault that becomes.

  When a switching power supply having an uninterruptible power supply (UPS) function is provided inside a computer device, there is an advantage that it can be made relatively small, but in general, voltage conversion is performed twice from AC to DC to DC. In terms of efficiency and mounting, it is inferior to ordinary power supplies.

  Further, when a lead-sealed battery or the like is used as a backup power source, the circuit becomes dedicated and complicated, such as a battery charging circuit and a DC output circuit when supplying the battery, and thus becomes expensive. In particular, since the power conversion efficiency when supplying power from the battery affects the backup time, it is essential to improve the power conversion efficiency.

  Recently, supercapacitors using materials with high energy density, such as electric double layer capacitors, have been developed. To use a supercapacitor as a backup power supply, countermeasures against voltage rise at power supply startup due to the increased capacity of the capacitor And use at high voltage becomes a problem.

  Next, problems due to the power source type of the backup power source will be described. By using a lead-sealed battery or a NiCd battery as the battery, and continuously charging the battery with a trickle charging method (a method that charges the battery with a small current while being disconnected from the load to compensate for self-discharge), a power failure, etc. Generally, power is supplied from a battery as soon as it occurs to enable backup. However, lead-sealed batteries and nickel-cadmium batteries have been regulated as environmentally hazardous substances, and as a result, power supplies that implement backup functions using batteries that have been used as secondary batteries, such as nickel metal hydride batteries and lithium batteries. Has appeared. However, nickel-metal hydride batteries and the like have a drawback in that the life of the trickle charging system is shorter than that of a lead-sealed battery because excessive charging or heat generation during charging greatly affects the battery life. Therefore, fine control such as intermittent charge control is required for charging the battery.

  In order to perform power backup without instantaneous interruption, it is preferable to keep the power supply circuit from the battery side in a standby state even during AC power feeding. In this case, the current consumption of the battery increases in order to maintain the standby state. Even in the case of performing the above-described intermittent charging, it is necessary to supplement the battery to compensate for this battery consumption, and the effect on the life of the supplemental charging occurs.

  The objective of this invention is providing the power supply device with an uninterruptible power supply function which solved each said subject.

  In order to solve the above problems, the present invention has a main circuit having a switching power supply configuration, a supercapacitor is used as a backup power supply, a charge / discharge circuit of the supercapacitor is separated from the main circuit, and The output is combined with the input winding of the switching transformer of the main circuit, and the backup power supply is configured to be stopped when the main circuit is normal, and the backup power supply is self-diagnosed during the suspension period. This is a configuration to be performed and is characterized by the following configuration.

(1) AC power from AC power is converted to DC power, AC power is obtained from the DC power at the output of the switching transformer by high-frequency switching using a switching circuit, and the AC power is rectified and smoothed to produce a constant voltage DC output. In a power supply device with an uninterruptible power supply function comprising a main circuit to be obtained, and a backup power supply device that supplies power necessary for the DC output from a backup power supply when the function of the main circuit is lost,
The backup power supply device includes a supercapacitor as the backup power supply, a charging control circuit for controlling charging of the supercapacitor using the DC side of the switching circuit as a power supply, and the supercapacitor as a power supply, and the switching circuit of the main circuit. A power failure guarantee circuit comprising a second switching circuit that is switching-controlled by the same voltage control signal, and the high-frequency output of the second switching circuit is connected to the switching circuit of the main circuit at the input winding portion of the switching transformer. It is characterized by the configuration combined with the output.

  (2) The circuit configuration is such that the output voltage of the second switching circuit is lower than the output voltage of the switching circuit of the main circuit, and both switching circuits are provided with diodes that prevent reverse flow through the switching transformer. It is provided.

  (3) The backup power supply device is characterized in that it includes a pause control circuit that pauses the second switching circuit when the main circuit is normal.

  (4) The suspension control circuit includes a self-diagnosis circuit for diagnosing the charging operation and discharging operation of the supercapacitor during the suspension period.

  As described above, according to the present invention, a supercapacitor is used as a backup power source, the charge / discharge circuit of this supercapacitor is separated from the main circuit, and the output from the backup power supply device is input to the input winding portion of the switching transformer of the main circuit. Therefore, the following effects can be obtained.

  (1) Supercapacitors can widen the operating voltage range, can be backed up for a longer time, and can realize a power supply device with a highly efficient uninterruptible power supply (UPS) function.

  (2) By placing the supercapacitor on the primary side of the power supply, the operating voltage range can be widened, and the capacity of the supercapacitor can be increased by lowering the operating voltage of the backup and power failure guarantee circuit for a longer time. Can be expected.

  (3) Since the backup power supply device is separated from the main circuit, the delay of the voltage rise at the time of starting the power supply can be reduced even when the capacity of the supercapacitor is increased.

  (4) A configuration in which the backup power supply is suspended when the main circuit is normal, and a configuration in which the backup power supply is self-diagnosed during the suspension period to reduce battery consumption and at regular intervals. The reliability of the pause circuit by the automatic diagnosis function is improved.

(Embodiment 1)
FIG. 1 shows a circuit configuration diagram of the present embodiment, and constitutes a power supply device with an uninterruptible power supply (UPS) function using a super capacitor as a backup power supply. In the figure, SC is a supercapacitor represented by an electric double layer capacitor.

  In FIG. 1, the main circuit includes a rectifier circuit 1 and an active filter 2 as AC-DC converters, a switching circuit 3 as DC-AC converters, a rectifier output circuit 4 as AC-DC converters, and an output. And a voltage control circuit 5. The active filter 2 obtains a filter operation in which the fundamental frequency component is suppressed by the chopper operation and converts the rectified output into a boosted DC power. The switching circuit 3 supplies the DC power smoothed by the smoothing capacitor C8 to the input of the switching transformer T1 as a high frequency sine wave power by the PWM control operation of the transistor Q2, and rectifies and smoothes the output of the transformer T1 by the rectification output circuit 4. To obtain a voltage of 5V. The output voltage control circuit 5 includes a voltage detection circuit VDET that detects an output voltage of the rectification output circuit 4, a photocoupler PC that insulates and takes in the voltage detection signal, and a PWM gate signal having a modulation rate according to the output of the voltage detection signal. And a PWM gate circuit GATE for generating.

  The power failure guarantee circuit includes a supercapacitor SC as a backup power supply, a charge control circuit CON that controls charging of the supercapacitor SC using the DC output of the active filter 2 as a power supply, and a high frequency sine wave power at the input of the transformer T1 using the supercapacitor SC as a power supply. The switching circuit SW for supplying The charge control circuit CON performs chopping control of the transistor Q4, charges the supercapacitor SC through the reactor L3 during the ON period, and releases the electromagnetic energy of the reactor L3 from the diode D5 as the charging current of the supercapacitor SC during the OFF period. . The switching circuit SW has the same output circuit configuration as that of the switching circuit 3, the high-frequency sine wave output is connected in parallel by a pair of input windings of the transformer T1, and the transistors Q2 and Q3 are PWM-controlled by the PWM control circuit 5 in common. .

  Here, the number of turns of both windings of the transformer T1 is designed so that the output voltage of the switching circuit SW is slightly lower than the output voltage of the switching circuit 3 in the transformer T1. Further, the high frequency sine wave output of the switching circuit SW is prevented from leaking to the other switching circuit 3 by the diodes D3 and D4.

  The operation of this embodiment will be described. When the power supply is started, a voltage of about DC 380 V is applied to the capacitor C8 of the switching circuit 3 by the rectifier circuit 1 and the active filter 2. The transistor Q2 is PWM-controlled based on this voltage, so that a 5V output is supplied from the rectification output circuit 4 to the load.

  At this time, the power failure guarantee circuit side converts the voltage from DC380V to a low voltage (DC24V or the like) considering the working voltage of the supercapacitor SC by the transistor Q4, the reactor L3, and the diode D5, and charges the supercapacitor SC with the electric charge. The transistor Q3 on the power failure guarantee circuit side repeats ON / OFF with a PWM waveform by the same feedback signal as that of the main circuit. However, when the AC power is normal, the transformer secondary side has a turn ratio of the transformer T1. Since the voltage on the main circuit side is constantly set higher, there is no output supply from the power failure guarantee circuit side to the load side (diode D4 has reverse polarity).

  After that, when a power failure occurs, output is supplied from the main circuit side for a while by the electric charge stored in the capacitor C8 on the main circuit side, but the capacitor voltage gradually decreases. When the capacitor voltage decreases and eventually the supply voltage on the power failure guarantee circuit side becomes higher, the diode D4 is turned on. Then, the output can be supplied to the load side for a predetermined time by the electric charge stored in the supercapacitor SC.

  When the AC power is restored during the backup operation by the supercapacitor SC, the main circuit side becomes higher as in the start-up, so that the output from the main circuit is automatically switched.

  As described above, the power failure guarantee circuit reduces the working voltage of the supercapacitor by separating the charge / discharge circuit of the supercapacitor SC from the main circuit and attaching it at the transformer winding portion. As a result, in order to enable backup for a longer time with the power failure guarantee circuit, when the capacity of the supercapacitor SC is increased, in this case as well, the supercapacitor SC is separated at the time of starting the power source, so that the voltage rise is accelerated. Moreover, the backup function can be realized by using a withstand voltage element having a low charge / discharge circuit of the super capacitor SC. In addition, by obtaining the charging power of the supercapacitor SC from the primary side of the transformer T1, it is possible to use the supercapacitor SC with a larger voltage change in charging and discharging as a backup power source. In other words, when a battery is used as the backup power source, the operating voltage range is narrowed, whereas in the supercapacitor SC, the operating voltage range can be widened, and a longer backup is possible.

(Embodiment 2)
FIG. 2 shows a circuit configuration of the present embodiment. 1 is different from FIG. 1 in that the active filter circuit 2 is omitted and the output control of the supercapacitor SC is stopped during power feeding by the main circuit, and automatic diagnosis is performed at regular intervals.

  The power failure guarantee circuit includes a supercapacitor SC as a backup power supply, a charge control circuit CON that controls charging of the supercapacitor SC using the DC output of the rectifier circuit 1 as a power supply, and a high frequency sine wave power at the input of the transformer T1 using the supercapacitor SC as a power supply. The switching circuit SW for supplying

  Here, the control circuit of the charge / discharge control circuit CON has the same circuit configuration as in FIG. 1 and controls the charging of the supercapacitor SC by the chopper operation, but the output control from the switching circuit 3 to the load side is usually performed. At times, the gate signal to the transistor Q3 is blocked by the gate circuit G, and the transistor Q3 is turned off (paused). When the charge / discharge control circuit CON detects a loss of function of the main circuit such as a power failure of the AC power supply or the start of a voltage drop of the capacitor C8, the charge / discharge control circuit CON stops the signal interruption by the gate circuit G, and the output voltage control circuit 5 Enable output control. This control minimizes the discharge power from the supercapacitor SC, thereby reducing the number of times the supercapacitor SC is charged, increasing the power conversion efficiency and extending the life of the supercapacitor SC.

  Next, the charge / discharge control circuit CON obtains a time signal from the timer T at regular intervals, and when the time signal is received during the above-described pause period, the charge / discharge control of the supercapacitor SC is operated only for a short time. Control for. By this control, for example, confirmation of the charging operation of the supercapacitor SC and confirmation of the switching operation of the transistor Q3 are obtained. This control improves the self-diagnosis of sleep control, that is, the reliability of the uninterruptible power supply function.

  In the first or second embodiment, the design of the main circuit configuration and the backup power supply device configuration can be changed as appropriate. For example, the charging of the supercapacitor SC is not limited to continuous charging, and the same operation effect can be obtained as an intermittent charging method. In the second embodiment, the active filter circuit 2 may be provided. The switching circuits 3 and SW may be pulse width control instead of PWM control.

The circuit diagram of the power supply device with an uninterruptible power supply function which shows Embodiment 1 of this invention. The circuit diagram of the power supply device with an uninterruptible power supply function which shows Embodiment 2 of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Rectification circuit 2 Active filter 3 Switching circuit 4 Rectification output circuit 5 Output voltage control circuit SC Supercapacitor CON Charge control circuit SW Switching circuit

Claims (4)

Main circuit that converts AC power of AC power source into DC power, obtains AC power from the DC power to the output of the switching transformer by high-frequency switching by the switching circuit, and rectifies and smoothes this AC power to obtain a constant voltage DC output And a power supply device with an uninterruptible power supply function comprising a backup power supply device that supplies power necessary for the DC output from a backup power supply when the function of the main circuit is lost,
The backup power supply device includes a supercapacitor as the backup power supply, a charging control circuit for controlling charging of the supercapacitor using the DC side of the switching circuit as a power supply, and the supercapacitor as a power supply, and the switching circuit of the main circuit. A power failure guarantee circuit comprising a second switching circuit that is switching-controlled by the same voltage control signal, and the high-frequency output of the second switching circuit is connected to the switching circuit of the main circuit at the input winding portion of the switching transformer. A power supply with an uninterruptible power supply function, characterized by a configuration combined with an output.   The output voltage of the second switching circuit has a circuit configuration that is lower than the output voltage of the switching circuit of the main circuit, and both switching circuits are provided with diodes that prevent reverse flow through the switching transformer. The power supply device with an uninterruptible power supply function according to claim 1.   The uninterruptible power supply function according to claim 1 or 2, wherein the backup power supply device is provided with a stop control circuit that stops the second switching circuit when the main circuit is normal. Power supply. The uninterruptible power supply according to any one of claims 1 to 3, wherein the suspension control circuit includes a self-diagnosis circuit that diagnoses the charging operation and discharging operation of the supercapacitor during the suspension period. Power supply with power supply function.

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