JPH08154347A - Uninterruptible ac power supply apparatus - Google Patents

Abstract

PURPOSE: To reduce a power consumption and extend the service life of an appliance by a method wherein the output voltage of an inverter is so adjusted as to be a voltage which is within the allowable voltage range of a load machine and with which the power consumption is minimized. CONSTITUTION: An AC power from a commercial AC power supply 1 is converted into a DC power by a rectifier 10 and used for charging a battery 20 and, at the same time, inputted to an inverter 30 which outputs an AC output 2 of a rated voltage as an initial voltage through a switch 41. Then, by changing a reference value 31 within the allowable input voltage range of a load machine, the inverter voltage is gradually changed and the respective products of the detected values of an output voltage detector 34 and the detected values of an output current detector 35 are obtained by a multiplier 33 along the lapse of time to measure the power consumption of the load machine. A CPU 32 stores an inverter voltage when the power value is minimum and fixes the reference value of the output voltage to that value and controls so as to have a power with that voltage supplied to the load thereafter. As a result, the power consumption can be reduced and the service life of an appliance can be extended.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention constantly supplies stable and constant voltage AC power to a load even when the power supply voltage fluctuates, and when the voltage of the power supply drops or a power failure occurs, an inverter using a storage battery as a power source supplies the load to the load. The present invention relates to energy saving measures for an AC uninterruptible power supply that continuously supplies electric power.

[0002]

2. Description of the Related Art A conventional example of an AC uninterruptible power supply is shown in FIG. In the figure, 1 is a commercial AC power supply, 2 is an AC output, 3 is a direct-feed circuit, 10 is a rectifier, 20 is a storage battery, 30 is an inverter, 31 is an inverter voltage reference value, and 40 and 41 are switching devices. In such a conventional device, the commercial AC power supply 1 is usually converted into DC power by the rectifier 10 and the storage battery 2 is used.
0 is charged and input to the inverter 30. The inverter 30 outputs a constant AC voltage according to the reference value 31 to the AC output 2 via the switch 41. In addition, when the commercial AC power supply 1 fails, the storage battery 20 continuously supplies power to the AC output 2 via the inverter 30 and the switch 41 without interruption. When the output current becomes overloaded again, or when the rectifier or the inverter fails, the switch 40 is switched without interruption to connect the direct feed circuit 3 to the AC output 2.

[0003]

Generally, in this kind of AC uninterruptible power supply, it has been said that the better the output constant voltage accuracy with respect to the rated voltage of the inverter 30, the better the performance of the inverter. However, the allowable input voltage range of an electronic device that is a load of the AC uninterruptible power supply is usually guaranteed to be about ± 10%, and in most cases, the performance is excessive in practical use.

In addition, the power supply efficiency of the power source part of the electronic equipment, which is the load of the apparatus, usually varies depending on the value of the AC input voltage even within the allowable voltage range. In addition, in lighting equipment such as incandescent lamps and fluorescent lamps, the illuminance decreases slightly even if the voltage is lowered by a few volts, but this is not a problem in actual use, and its power consumption can be reduced. It can be expected to extend the service life.

[0005]

According to the present invention, the most efficient voltage of the load device, that is, the power consumption is minimized within the allowable input voltage range of the load device, without sticking to unnecessary excessive inverter output voltage accuracy. The voltage is determined, the output voltage of the inverter is set to the recognition voltage, and stable electric power is supplied at a fixed voltage value both steadily and transiently.

That is, according to the present invention, in such an AC uninterruptible power supply, after the power of the load equipment is stabilized after the start of operation by the inverter, the inverter voltage is gradually increased within a permissible input voltage range of the load equipment at regular intervals. By changing the voltage, the power consumption of the load device, that is, the AC voltage at which the output power of this device is the minimum is judged and recognized, and the inverter output voltage value is set and fixed to that judgment voltage, and power is supplied to the load equipment at that voltage. The present invention intends to provide a power supply device that realizes energy saving as a system including a load device of the power supply device.

[0007]

1 is a circuit diagram showing an embodiment of an AC uninterruptible power supply device of the present invention.

The operation of FIG. 1 will be described. Commercial AC power supply 1
Is converted into DC power by the rectifier 10 to charge the storage battery 20 and input to the inverter 30. The inverter 30 outputs an AC output having a rated voltage as an initial voltage to the AC output 2 via the switch 41. Next, the inverter voltage is gradually changed by changing the reference value 31 within the range of the allowable input voltage of the load device. Then, the detected value of the output voltage detector 34 and the detected value of the output current detector 35 at that time are multiplied by the multiplier 33, and the output power, that is, the power consumption of the load device is measured. The CPU 32 stores the inverter voltage (equivalent to the reference value 31) when the power value becomes the minimum, and thereafter fixes the reference value of the inverter output voltage at this value, and thereafter supplies this voltage to the load. To control.

When the commercial AC power supply 1 fails, the storage battery 20 continuously supplies power to the AC output 2 via the inverter 30 and the switch 41 without interruption. In this case as well, the inverter voltage outputs the determination voltage.

When the output current becomes overloaded, or when the rectifier or the inverter fails, the switching device 40 is switched without instantaneous interruption to output the direct-current circuit 3 to the AC output 2 as in the conventional device. Connect to.

According to the present invention, the most efficient voltage of the load device within the allowable input voltage range of the load device, that is, the voltage at which the power consumption is minimized is determined, and the output voltage of the inverter is set to that voltage during normal operation. However, the stable power can be supplied at a voltage at which the load device can operate most efficiently.

[0012]

As described above, the power supply portion of the electronic equipment, which is the load of the device of the present invention, usually has a high power supply efficiency due to the value of the AC input voltage even within the allowable voltage range depending on the circuit system of the power supply. It fluctuates as it goes down and down. And not necessarily the rated input voltage (eg AC100
It is often not designed for maximum device efficiency in V). In the case of lighting equipment such as incandescent lamps and fluorescent lamps, if the illuminance is within the range and the input voltage is within the allowable range, the power consumption can be reduced by lowering the input voltage, and the life of the equipment is expected to be extended. it can. Therefore, by supplying power to the load device by the operation method of the AC uninterruptible power supply according to the present invention, the power consumption of the load device and the amount of heat generated can be reduced, and the life of the load device can be expected to be extended. In addition, the overall efficiency of the device of the present invention and the load device is improved, and the accumulated power cost can be suppressed to a low cost.

[Brief description of drawings]

FIG. 1 is a circuit diagram showing an embodiment of an AC uninterruptible power supply device of the present invention.

FIG. 2 is a circuit diagram of a conventional device.

[Explanation of symbols]

 1 Commercial AC Power Supply 2 AC Output 3 Direct Transfer Circuit 10 Rectifier 20 Storage Battery 30 Inverter 31 Reference Value 32 CPU 33 Multiplier 34 Output Voltage Detector 35 Output Current Detector 40 Switcher 41 Switcher

Claims (1)

[Claims] 1. A constant constant-current AC power is constantly supplied to a load even when the power supply voltage fluctuates, and the power is continuously supplied to the load by an inverter using a storage battery as a power source when the power supply voltage drops or a power failure occurs. In the AC uninterruptible power supply to be supplied, it has a function to detect the output power of this device, that is, the power consumption of the load equipment and a function to change the inverter voltage, and by changing the inverter voltage within the input allowable voltage range of the load equipment, An energy-saving AC uninterruptible power supply that determines the most efficient load device voltage that consumes less power and fixes the inverter output voltage at that voltage.