JPH0530678A - Uninterruptible power source - Google Patents

Abstract

PURPOSE:To judge a decrease in discharging capacity of a storage battery without necessity of a particular facility by providing first phase control means for operating a converter, second phase control means for operating an inverter, means for controlling discharge of the battery, and means for deciding a voltage of the battery, propriety of the battery. CONSTITUTION:An AC voltage of a commercial power source 1 is supplied to a DC load 6 through an AC reactor 2, a converter 3 and a D/D converter 5. At the time of maintenance and inspection of a storage battery 4, an analog switch 35 is switched from an error amplifier 16 side to an error amplifier 34 side. In this case, an input of a PLL circuit 17 is so formed as to invert its polarity, the converter 3 is switched from a lag phase to a lead phase to perform an inverter operation, DC power of the battery 4 is supplied to the load through the converter 5, and further regenerated to the power source 1 through the converter 3 and the reactor 2. Here, the discharge amount of the battery 4 is adjusted by a predetermined DC power reference 33.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an uninterruptible power supply device for supplying a load with electric power from a storage battery when a commercial power supply fails, and has a function of determining the quality of a storage battery without providing a special load device. Related to uninterruptible power supply.

[0002]

2. Description of the Related Art An uninterruptible power supply (hereinafter simply referred to as UPS) equipped with a storage battery and capable of continuously supplying power to a load without interruption
It has become indispensable in the advanced information society of recent years. In addition, as the functional purpose of the load is being clarified and the number of types of load is increasing at the same time,
Various types are also used in the basic configuration of the uninterruptible power supply. If you give an example of a special uninterruptible power supply,
With a DC power supply type uninterruptible power supply device that directly supplies DC power from a commercial power source to a load via a rectifier, or a parallel type uninterruptible power supply device that operates by always connecting the commercial power supply and the inverter output in parallel. is there.

The configuration of a conventional DC power supply type uninterruptible power supply will be described with reference to FIG. In the figure, 1 is a commercial power source, 2 is an AC reactor, 3 is a semiconductor element such as a transistor, and is a self-exciting converter having a function of charging a storage battery 4, and 5 requires a DC voltage from a DC load 6. DC / DC converter (hereinafter D
/ D converter).

The operation of the DC power supply type uninterruptible power supply will be briefly described below. When the commercial power source 1 is in a healthy state, the AC power of the commercial power source 1 is converted via the AC reactor.
The DC power is converted by the converter 3, a part of this DC power charges the storage battery 4, and the other is converted into a predetermined DC voltage by the D / D converter 5 and supplied to the DC load 7.

In the event of a power failure of the commercial power source 1, the converter 3
The DC power of the storage battery 4 to the D / D converter 5
Is converted to a predetermined DC voltage in order to maintain uninterrupted power supply so that the load power supply can be continued for a predetermined discharge time.

Next, the control circuit of the converter 3 will be described with reference to FIG. In the figure, 11 and 12 are a commercial power source, an AC voltage detector such as an insulating transformer for converting the voltage of the input voltage of the converter 3 into the voltage of the control circuit level,
18 is a comparator for comparing the voltage of the commercial power supply 1 with the input voltage of the converter 3, 19 is an error amplifier for amplifying the error component of the comparator 18 by proportional / integrating, 13 is for insulating and controlling the voltage of the storage battery 4. DC voltage detector that converts to circuit level voltage,
Reference numeral 15 is a DC voltage reference, 16 is an error amplifier that proportionally / integrates and amplifies an error amount generated by comparing the outputs of the DC voltage reference 15 and the DC voltage detector 13 with the comparator 14, and the error amplifier 1.
The output of 6 serves as one input of the PLL circuit 17, and gives a predetermined phase difference to the PLL circuit 17 which operates on the phase basis of the commercial power supply 1. Reference numeral 20 denotes a voltage control circuit, which outputs a predetermined phase reference θ according to the output signal of the PLL circuit 17.
^* And a predetermined voltage reference V ^* by the output signal of the error amplifier 19 for adjusting the input voltage of the converter 3 to the commercial power supply 1 ^. It has a function of converting into a base signal of a predetermined pulse train from the two inputs. The base drive circuit 21 is for isolating and amplifying the base signal and controlling the semiconductor element group used in the converter 3. That is, the self-exciting converter controls the reactive power with respect to the commercial power source 1 by adjusting the magnitude of the input voltage of the converter 3, and the phase difference with the commercial power source 1, that is, the lag phase here. By adjusting this, it is possible to control active power with the commercial power supply 1.

To briefly explain the advantage of using the self-exciting converter, unlike the general thyristor type rectifier, active power and reactive power can be controlled independently, and the input power factor is 1. Control to minimize the required input capacity of the uninterruptible power supply, if the semiconductor element of the self-exciting converter is a pulse train with a predetermined pulse width (called PWM method). The point is that the harmonic current generated in the commercial power supply 1 can be suppressed.

[0008]

The important items for maintenance of the uninterruptible power supply having such a structure are mechanically operating parts having a rotating part such as a cooling fan, electrolytic capacitors, storage batteries, etc. It is a component that has the chemical reaction of.

In particular, the storage battery is an uninterruptible key component and has a problem that it is difficult to determine the life of the storage battery, although the cost of the equipment for the entire system is high. As the current life discrimination, the manufacturer expects the expected life depending on the type of the storage battery, and the storage battery is replaced according to the expected number of years of the life, but generally a chemical reaction like the storage battery is used. If the ambient temperature rises by 10 ° C, the service life of the used products will be halved, and the service life will vary greatly depending on the environment in which the storage battery is used. In addition, there is a method of performing a discharge test as a method of accurately knowing the life of the storage battery that is actually used, but in order to perform a discharge test, a predetermined load facility is necessary, especially the capacity of the uninterruptible power supply device. If it becomes large, it is practically impossible to bring the load equipment to the site where it is actually operating and perform the discharge test.

Therefore, the storage battery used for the uninterruptible power supply is to be replaced within the expected life, and depending on the system environment, the storage battery which can actually be used for several years may be replaced and the maintenance cost may be wasted. When a storage battery that has already reached the end of its life is used and the commercial power supply 1 loses power and backs up the load 7, there is a risk that a predetermined backup time cannot be secured and the load power supply is stopped. is there.

Therefore, an object of the present invention was made in view of the above-mentioned point, and in an uninterruptible power supply system including a converter, a storage battery, etc., a storage battery for judging the replacement time of the storage battery. An object of the present invention is to provide an uninterruptible power supply device that does not require special equipment to determine the quality of the storage battery and has a function of determining the deterioration of the discharge capacity of the storage battery.

[0012]

In order to achieve the above object, the present invention has a self-exciting converter for converting an alternating current supplied from a commercial power source into a direct current, and a storage battery, and when the commercial power source is abnormal, In the uninterruptible power supply device having means for continuing power supply from the storage battery to the load, the self-exciting converter
A first phase control means for delaying the phase of the converter with respect to the commercial power source to operate the converter; a second phase control means for advancing the phase to operate the inverter; and the self-exciting converter. A means for controlling the discharge of the storage battery to a predetermined value when operating as an inverter, and a means for judging the quality of the storage battery based on the parameters such as the storage battery voltage and the discharge time at the time of discharging the storage battery are provided. It is characterized by that.

[0013]

When the quality of the storage battery is judged by the configuration as described above, the inverter operates the converter to discharge the storage battery, and the parameters such as the storage battery voltage and the discharge time when the storage battery is discharged are set. Since it is possible to determine the quality of the storage battery based on the data, it is possible to determine the correct replacement time of the storage battery.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIG. In FIG. 1, since the components having the same numbers as in the conventional example of FIG. 4 have the same functions, the description thereof will be omitted.

This embodiment FIG. 1 is different from the conventional example in that a DC current detector 10 is added and a DC voltage detector 13 is added.
Output of the storage battery 4 is integrated with the output of the multiplier 31 to detect the discharge power of the storage battery 4, the DC power reference 33 is compared with the comparator 32, and the error is proportionally and integrated via the error amplifier 34. The configuration is such that one input of the analog switch 35 can be switched to the constant DC voltage control.

Further, the analog switch 35 selects the error amplifier 34 side for constant DC power control, and at the same time the storage battery 4 is selected.
The point is that a storage battery diagnostic circuit 36 for monitoring the level of the DC voltage is provided.

Next, the operation of the present invention will be described. Normally, the analog switch 35 selects the error amplifier 16 side for constant DC voltage control, and the AC voltage of the commercial power supply 1 is transmitted through the AC reactor 2, the converter 3, and the D / D converter 5 to the DC load 7 Is feeding. During maintenance and inspection of the storage battery 4, the analog switch 35 is switched from the error amplifier 16 side to the error amplifier 34 side. At this time, the PLL circuit 1
The input of 5 is configured so that the polarity is inverted,
The inverter 3 is switched from the delayed phase to the advanced phase and operates as an inverter, and the DC power of the storage battery 4 is converted to the D / D converter.
In addition to supplying power to the load via the converter 5, the converter 3
Also, it is regenerated to the commercial power source 1 via the AC reactor 2. Here, the discharge amount of the storage battery 4 is a predetermined DC power reference 33
It is possible to set the amount of electric power by adjusting the electric power.

Next, the structure of the storage battery diagnosis circuit 36 will be described with reference to FIG. A timer-361 that starts a timer when the analog switch 35 is switched to the error amplifier 34 side, that is, when the storage battery 4 is discharged with a predetermined amount of power.
The timer 361 is configured so that the timer is up at a predetermined time and the flip-flop circuit 365 can be set when the timer operates.

The DC voltage of the storage battery 4, which is an input of the storage battery diagnostic circuit 36, is compared with a predetermined storage battery voltage reference 362 by a comparator 363, and when the former becomes smaller than the latter, the output of the comparator 363 becomes effective. One-shot circuit 36
It is configured such that it becomes the set side input of the flip-flop circuit 365 via the circuit 4. Next, the operation of this circuit will be described with reference to FIG.

The discharge time-storage battery voltage characteristic of the storage battery is shown in FIG.
The discharge curve moves inward as the deterioration of the storage battery progresses, and it can be determined that the storage battery 2 is deteriorated more than the storage battery 1 in FIG. Here, it is assumed that the timer 361 sets the value of the storage battery voltage reference 362 to VB ^{* at} time t0 ^. When set to, in the storage battery 1, the battery voltage is the storage battery voltage reference VB ^*. When it drops to ^* Since the interval is t1, which is longer than the timer set value t0, the flip-flop circuit 365 is not set and the alarm signal is not output.

On the contrary, in the storage battery 2, the battery voltage is the storage battery voltage reference VB ^*. Since the time t2 of falling to 0 is shorter than t0, the flip-flop circuit 365 is set and an alarm signal is output, so that the user can be notified of the deterioration of the life of the storage battery.

In the above-mentioned embodiment, the DC power supply type uninterruptible power supply device has been described as an example. However, in the configuration of the parallel type uninterruptible power supply device, etc., the self-exciting converter and the storage battery are provided. Inverter with a similar control circuit configuration
The same effect can be obtained by operating the switch.

[0023]

As described above, according to the present invention, a self-exciting converter for converting an alternating current supplied from a commercial power source into a direct current and a storage battery are used, and the power of the storage battery is used when the commercial power source is abnormal. In the uninterruptible power supply equipped with a means for continuing the load power supply, when determining the quality of the storage battery, operate the self-exciting converter to operate the inverter to discharge the DC power of the storage battery at a predetermined amount and simultaneously discharge the storage battery. Since it is configured to monitor the battery voltage and discharge time at the time,
It is possible to determine the replacement time of the storage battery by performing a discharge test of the storage battery in a short time without requiring special test equipment.

[Brief description of drawings]

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

FIG. 2 is a block diagram showing a specific example of a storage battery diagnosis circuit in FIG.

FIG. 3 is a characteristic diagram of a discharge time and a battery voltage of a storage battery for explaining the operation of FIG.

FIG. 4 is a block diagram of a conventional uninterruptible power supply device.

[Explanation of symbols]

1 ... Commercial power supply 2 ... AC reactor 3 ... Converter 4 ... Storage battery 5 ... D / D converter 6 ... DC load 10 ... DC current detector 11, 12 ... AC voltage detector 13 ... DC voltage detector 14, 18, 32 ... Adder 15 ... DC voltage reference 16, 19, 34 ... Error amplifier 17 ... PLL circuit 20 ... Repression control circuit 21 ... Base drive circuit 31 ... Multiplier 33 ... DC power reference 35 ... Analog switch 36 ... Storage battery diagnostic circuit 361 ... Timer-362 ... Storage battery voltage reference 363 ... Resistor 364 ... One-shot circuit 365 ... Flip-flop

Claims (1)

Claim: What is claimed is: 1. A self-exciting converter for converting an alternating current supplied from a commercial power supply into a direct current, and a storage battery. When the commercial power supply is abnormal, power is continuously supplied from the storage battery to a load. In the uninterruptible power supply device including means, first self-exciting converter delays the phase with respect to the commercial power source to operate the converter, and phase advances to operate the inverter. Second phase control means, means for controlling the discharge of the storage battery to a predetermined value when the self-exciting converter operates as an inverter, and parameters such as storage battery voltage and discharge time when the storage battery is discharged. An uninterruptible power supply device comprising means for determining the quality of the storage battery based on the battery.