JPH0352525A - Dc power supply circuit - Google Patents

Abstract

PURPOSE:To reduce power loss and heat dissipation by a method wherein a load is supplied with power by an exclusive rectifier while a battery is charged by an exclusive booster charger at a voltage higher than the voltage to the load. CONSTITUTION:When an AC input is normal, a load is supplied with power by an exclusive AC/DC converter 1. A battery is charged by an exclusive booster charger 6 at a voltage that is several volts higher than the voltage to the load. When the service interruption of the AC input is caused, a service interruption monitoring circuit 7 is started to start a first control circuit 8 and operate a load voltage compensating means 3. Further, the power is supplied by the battery 2 and the booster charger 6 is stopped. A second control circuit 9 is stated by the starting of the service interruption monitoring circuit 7 to operate a magnetic contactor 4. The thyristor and the diode of the load voltage compensating means 3 are bypassed and the voltage of the battery 2 is supplied to the load as it is. According to this method, a power loss or the generation of heat due to a dropper may be reduced.

Description

[Detailed Description of the Invention] [Summary] This invention relates to a DC uninterruptible power supply system consisting of an AC/DC converter that converts AC input to DC and a battery for backup in the event of an AC input power outage. In order to prevent power loss and heat generation from increasing due to voltage compensation means, we have developed an AC/DC converter that converts AC input into DC, a backup battery in the event of an AC input power outage, and a load voltage compensation means such as a silicon dropper. In a DC power supply circuit consisting of a magnetic contactor that short-circuits the load voltage compensation means and an auxiliary power supply circuit that supplies auxiliary power to the control circuit, a booster charger that charges a backup battery and the presence or absence of an AC input power source are monitored. a first control circuit for activating the load voltage compensation means upon activation of the power failure monitoring circuit; and a second control circuit for activating the magnetic contactor after a predetermined period of time after activation of the power failure monitoring circuit. A circuit is provided so that the output of the AC/DC converter is always used for power supply to the load, and the backup battery voltage charged by the booster charger is used for power supply to the load when the AC input power supply is interrupted.

[Industrial application field]

The present invention relates to a DC power supply circuit in a DC uninterruptible power supply system comprising an AC/DC converter that converts AC input to DC and a backup battery in the event of an AC input power outage.

A DC power supply circuit converts an AC power supply of 100V or 200V into a DC power supply of 48V or 24V, and is used as a power supply for communication devices or for emergency purposes. For communication devices and emergency power supplies, a floating charging method is adopted, in which input AC power is converted to DC power using a floating charger with battery backup, and power is supplied to the load while charging the battery. ．． In recent years, the use of semiconductor devices in load devices has progressed, and as a result, the power supplies that drive the load devices are required to have higher voltage accuracy and quality.

[Conventional technology]

A circuit diagram of a conventional DC power supply circuit is shown in FIG. In the figure, 11 is an AC/DC converter, 12 is a backup battery, 13 is load voltage compensation means, 14 is a magnetic contactor, 15 is an auxiliary power supply circuit, and 16 is an output voltage control circuit.

An AC input voltage of 100V or 200V is inputted to the AC/DC converter 11, converted to a DC voltage of 54V, and charged to the backup battery 12. At the same time, the load voltage compensator 13 consisting of a silicon dropper lowers the voltage to 6V and outputs the voltage. A voltage of 48V is supplied to the load.

The backup battery 12 is constantly charged with a DC voltage of 54V.

When the AC input voltage stops due to a power outage or the like, the DC supply from the AC/DC converter 11 is stopped and switched to the DC voltage supply from the backup battery 12. The output voltage dropped by the load voltage compensation circuit 13 is compared with the reference voltage obtained by the auxiliary power supply circuit 15 by the output voltage control circuit 16, and when the output voltage becomes lower than the reference voltage due to discharge of the backup battery 12. , operates the magnetic contactor l4, and short-circuits the load voltage compensating means 13 by its operating contact to boost and adjust the output voltage.

When the AC power outage is restored, the DC supply from the AC/DC converter l1 is resumed, charging of the backup battery 12 is started again, the load supply voltage and the reference voltage are compared by the output voltage control circuit 16, and the output voltage is higher than the reference voltage. At that time, the magnetic contactor 14 is restored and the load voltage compensating means 13 is inserted into the output circuit to step down the output voltage and supply it to the load.

FIG. 5 shows the output voltage transition waveform of the above-mentioned conventional DC power supply circuit. In the figure, ■' is the battery charging voltage, ■゜ is the output voltage, ■゛ is the upper limit of the output voltage fluctuation tolerance range, and ■
゛ indicates the lower limit value.

The DC power supply circuit must supply DC power to the load while charging the battery, so it charges at a voltage slightly higher than the battery's discharge voltage, so the charging voltage must be lowered by a few volts to avoid exceeding the allowable voltage of the load. Then, it becomes necessary to supply power to the load. [Problem to be Solved by the Invention] Conventionally, load voltage compensation means such as a silicon dropper has been used as a method of lowering the battery charging voltage by several volts, and this dropper is constantly inserted while the output voltage is being supplied. Therefore, this dropper caused power loss and increased heat generation.

The present invention aims to reduce the power loss and heat generation of the dropper that cannot be avoided in the conventional system when supplying power to a load. For this reason, a dedicated rectifier is used to supply power to the load, and a dedicated charger (booster charger) is used to charge the battery, which raises the voltage by several volts above the load power supply voltage. [Means for Solving the Problems] FIG. 1 shows a diagram of the principle structure of the present invention. In the figure, l is an AC/DC converter that converts AC input to DC, 2 is a backup battery in case of an AC input power outage, 3 is a load voltage compensation means such as a silicon dropper, and 4 is a magnet that short-circuits the load voltage compensation means. A contactor, 5 is an auxiliary power supply circuit that supplies auxiliary power to the control circuit, 6 is a booster charger that charges a backup battery, 7 is a power failure monitoring circuit that monitors the presence or absence of AC input power, and 8 is activation of the power failure monitoring circuit. 9 indicates a first control circuit for starting the load voltage compensating means, and 9 indicates a second control circuit for starting the magnetic contactor after a certain period of time from the start of the power failure monitoring circuit.

The output of the AC/DC converter 1 is always used for power supply to the load, and the voltage of the backup battery 2 charged by the data star charger 6 is used for power supply to the load when the AC input power supply is interrupted. This method uses the battery 2 only when the AC input is out of power and the AC/DC converter 1 and booster charger 6 have stopped outputting.
This method connects the load to the load.

[Effect]

When the AC input is normal, power is supplied to the load by a dedicated AC/DC converter 1, and battery charging is performed by a dedicated booster charger 6.

When there is a power outage in the AC input, the power outage monitoring circuit 7 is activated and the first
The control circuit 8 is activated to operate the thyristor that controls the load voltage compensation means 3, and the battery 2 is connected to the load power supply circuit through a diode dropper, and DC power supply is continued by discharging the battery 2. At the same time, the operation of the booster charger 6 is stopped. Next, the second control circuit 9 is activated by activation of the power failure monitoring circuit 7, and after a certain period of time has elapsed, the magnetic contactor 4 is operated, and the thyristor and diode of the load voltage compensation means 3 are bypassed.
The voltage of battery 2 is supplied directly to the load.

When the power outage is restored, the power outage monitoring circuit 7 monitors the AC input, restores the magnetic contactor 4 by operating in the opposite manner to that at the time of the power outage, disconnects the battery 2 and the AC/DC converter 1, and connects the booster charger 6 to the AC/DC input. The operation of the DC converter 1 is started, and battery charging and load power supply are restarted.

〔Example〕

FIG. 2 shows a circuit configuration diagram of an embodiment of the present invention.

In the figure, l is an AC/DC converter, 2 is a battery, 3 is a load voltage compensation means, 4 is a magnetic contactor, 5 is an auxiliary power supply circuit, 6 is a booster charger, 7 is a power failure monitoring circuit, and 8 is a first control The circuit 9 indicates a second control circuit.

The load voltage compensation means 3 includes a diode D6. The magnetic contactor 4 consists of an MC relay and a contact hole, and bypasses the load voltage compensating means 3 by the operation of the IIIC contact. The auxiliary power supply circuit 5 includes a transistor TRI, a Zener diode DI, and a resistor R.
l, capacitor CI, and 12 to the second control circuit 9.
Supply V voltage. The booster charger 6 is a 6V converter and constantly charges the battery 2 with a 54V voltage. The power failure monitoring circuit 7 consists of a photocoupler PCI, a resistor, a capacitor, a rectifier circuit, and a transformer, and rectifies AC voltage into DC to monitor the presence or absence of AC input voltage. In the event of a power failure, the photocoupler PCI is restored and starts the control circuit.

The second control circuit 9 is a photocoupler PCI, PC2, PC3.
and transistor TR2. It consists of a TR3, a timer relay TM, etc., and when the photocoupler PCI is restored in the event of a power outage, the photocoupler PC2 and PC3 are activated, and the first control circuit 8 is activated and the booster charger 6 is stopped. In the first control circuit 8, the thyristor Tll is made conductive by the operation of the photocoupler PC2, and the silicon dropper D6 of the load voltage compensating means 3 is turned on. D7 and Cyrisk THI are inserted, and the charging voltage of 54V from battery 2 is dropped by 6v to supply a voltage of 48V to the load.

In the second control circuit 9, the timer relay TM is activated after a certain period of time, the tm contact operates the magnetic contactor MC4, the IIIC contact bypasses the Cyrisk THI and the dropper 06.07, and the voltage of the battery 2 is directly applied to the load. supply to Due to the anal contact operation, the thyristor THI has no current and is turned off.

When the power outage is restored, the photocoupler PCI of the power outage monitoring circuit 7 operates, and the contactor MC4
is restored, the battery 2 and the AC/DC converter 1 are disconnected, the booster charger 6 and the AC/DC converter 1 are started to operate, and battery charging and load power supply are restarted.

Figure 3 shows the output voltage waveform transition of this example. In the figure, ■ indicates the battery charging voltage, ■ indicates the output voltage, ■ indicates the upper limit of the output voltage fluctuation tolerance range, and ■ indicates the lower limit. The battery charging voltage is charged by the booster charger 6 at a voltage several volts higher than the output voltage, and during a power outage the output voltage begins to drop temporarily, but silicon droppers D6 and D7 are inserted into the output circuit due to the operation of the thyristor TH1. After a certain period of time, the MC contactor 4 operates to create a bypass route and supply the voltage of the battery 2 directly to the load. Cyrisk T}11 has also been restored,
When the power is restored, the MC contactor 4 is restored and the voltage from the AC/DC converter 1 is supplied to the load, and the battery 2 is also charged by the booster charger 6 as shown by the dotted line. [Effects of the Invention] Compared to the conventional system, the present invention can reduce the consumption and heat generated by the dropper diode, and because the power is applied to the dropper diode and the switch thyristor for a short time, the heat dissipation fins etc. can be made smaller and the size can be significantly reduced. It is possible to downsize the system.

Furthermore, since the booster charger for charging the battery is boosted to the output of the AC/DC converter, it can be made smaller.

[Brief explanation of drawings]

Fig. 1 is a diagram of the principle configuration of the present invention, Fig. 2 is a circuit diagram of the embodiment, Fig. 3 is an output voltage transition waveform diagram of the embodiment, Fig. 4 is a circuit diagram of the conventional example, and Fig. 5 is a circuit diagram of the embodiment. The figure shows the output voltage transition waveform diagram of the conventional example. In the figure, l, 11 is an AC/DC converter, 2, 1
2 is a battery, 3.13 is a load voltage compensation means, 4.1
4 is a magnetic contactor, 5.15 is an auxiliary power supply circuit, 6
1 is a booster charger, 7 is an AC power outage monitoring circuit, 8 is a first control circuit, 9 is a second control circuit, and 16 is an output voltage control circuit.

Claims (1)

[Claims] AC/DC converter (1) that converts AC input to DC
and backup battery in case of AC input power outage (2)
and a load voltage compensation means (3) such as a silicon dropper.
a magnetic contactor (4) shorting the load voltage compensation means;
and an auxiliary power supply circuit that supplies auxiliary power to the control circuit (
5), a booster charger (6) that charges the backup battery (2), a power outage monitoring circuit (7) that monitors the presence or absence of an AC input power supply, and a power outage monitoring circuit that, upon activation of the power outage monitoring circuit, a first control circuit (8) for starting the load voltage compensating means (3); and a second control circuit for starting the magnetic contactor (4) after a certain period of time from the start of the power failure monitoring circuit (7). (9) and the AC/DC converter (
A DC power supply circuit characterized in that the output of 1) is always used for power supply to the load, and the voltage of the backup battery (2) charged by the booster charger (6) is used for power supply to the load during a power outage of the AC input power supply. .