JPH11252826A - Uninterruptive power supply - Google Patents

Abstract

PROBLEM TO BE SOLVED: To conduct automatic switching without previously-confirming the environment of a commercial electric power source by measuring the fluctuating frequency of an AC power source of the commercial power source and the discharging depth of a storage battery, comparing them with a preset discriminating value, and conducting automatic switching between an OFF line system and an ON line system. SOLUTION: When the frequency of voltage failure of a commercial power source 11 in a preset monitoring period is higher than a prescribed reference value, a signal of switching an OFF line system to an ON line system is outputted to an inverter 14 and a power switch 15 from a power switching controller 54. When the frequency of voltage failure of the commercial power source 11 in a preset monitoring period is lower than the reference value, a signal of switching the ON line system to the OFF line system is outputted. It is thus possible to attain lower noise and more energy saving than in a conventional ON line system and conduct automatic switching between ON line and OFF line systems according to the condition of the commercial power source 11, thereby improving generality and reliability.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to switching of a power supply method to a load in an uninterruptible power supply.

[0002]

2. Description of the Related Art Uninterruptible power supplies using a conventional commercial power supply can be roughly classified into a system in which power is always supplied by an inverter (online system) and a system in which power is always supplied by a commercial power supply (offline system). There is. And which method is selected, a) quality of commercial power supply,
b) The allowable voltage fluctuation of the load to be used, c) the cost, etc. FIG. 4 shows a general circuit block diagram of the uninterruptible power supply of the online type and the offline type. The online system and the offline system have almost the same circuit configuration. That is, the commercial power supply 1
1 is converted into a DC voltage by the rectifier 12,
Used for input of the inverter 14 or charging of the lead storage battery 13. Power from the rectifier 12 or the lead storage battery 13 is supplied to the inverter 14. Then, the power of the commercial power supply 11 is supplied to the load 16 as it is or
Is supplied to the load 16 by the power switch 15. The online method and the offline method have the following characteristics, respectively.

In the online system, the inverter 14 is normally used.
Is operated to supply electric power to the load 16. Then, when the output from the inverter 14 becomes excessive or when the inverter 14 fails, the power supply switch 15 is used to switch the power supply from the inverter power supply to the commercial power supply.
That is, in the online system, since the inverter is always supplied with power, a stable voltage can be supplied to the load 16. Therefore, it is mainly used in places where the fluctuation of the commercial power supply voltage is large, loads with a small allowable voltage fluctuation value, and the like. However, since the rectifier 12 simultaneously supplies power to the inverter 14 and charges the lead storage battery 13, a large capacity is required and the cost is high. Further, in order to suppress heat generation by the inverter 14 and the rectifier 12, a large-sized cooling fan is required, resulting in a problem that noise is increased. Therefore, when the online method is used, there is also a problem that the ventilation port is clogged due to the use of a large-sized cooling fan, and periodic maintenance and inspection are required because of a large accumulation of dust and the like inside.

On the other hand, the off-line system is a system in which the voltage of the commercial power supply 11 is always supplied to the load 16. And
In the event of a power outage or abnormal voltage of the commercial power
Is operated, and the power supply changeover switch 15 is switched to change the load 16
To supply power. In addition, since the inverter 14 is not operated at all times, there are advantages such as energy saving, no noise caused by the cooling fan, and little clogging of the ventilation port. However, when the off-line uninterruptible power supply is used in an environment where the power supply is not good, the inverter power supply and the commercial power supply are frequently repeated. Therefore, the depth of discharge of the storage battery used increases, and as a result,
There is a problem that the life of the storage battery is short. Note that in order to confirm the power supply situation of the commercial power supply, a long-term measurement using a voltmeter, an oscilloscope, a data recorder, and the like is required on site, and there is a problem that it takes time and effort.

[0005]

SUMMARY OF THE INVENTION It is an object of the present invention to automatically switch between an online system and an offline system in accordance with a fluctuation state of a commercial power supply without having to confirm the environment of the commercial power supply in advance. It is to provide an uninterruptible power supply.

[0006]

According to a first aspect of the present invention, there is provided a rectifier for converting an AC voltage of a commercial power supply to a DC voltage and supplying the DC voltage to an inverter and a storage battery, and converting the DC voltage to an AC voltage. An inverter, a storage battery that supplies a DC voltage to the inverter, a commercial power supply monitoring circuit that monitors the AC voltage of the commercial power supply, and a power supply switch for switching between power supply from the commercial power supply to the load and power supply from the inverter to the load. The uninterruptible power supply having
If the number of occurrences of the abnormal voltage of the commercial power supply during the monitoring period set in advance is larger than a predetermined reference value, a signal for switching from the offline mode to the online mode is output to the inverter and the power switch, and the monitoring period set in the preset period is set. When the abnormal voltage of the commercial power supply is smaller than the reference value, the inverter and the power supply switch have a power supply switching control unit that outputs a signal for switching from the online method to the offline method.

In the second invention, the power supply switching control unit according to the first invention is arranged such that when the frequency of occurrence of abnormality in the frequency, phase and waveform of the commercial power supply is larger than a predetermined reference value in a monitoring period set in advance. A signal for switching from the off-line system to the on-line system is output to the inverter and the power supply changeover switch, and when the frequency of occurrence of the frequency, phase, and waveform abnormalities of the commercial power supply is smaller than a predetermined reference value in a preset monitoring period. And a power supply switching control unit for outputting a signal for switching from the online method to the offline method to the inverter and the power supply changeover switch.

In a third aspect of the present invention, the power supply switching control unit according to the first or second aspect of the present invention sets the reference value of the number of occurrences of abnormality for the monitoring period of the commercial power supply and any one of voltage, frequency, phase and waveform. It can be set by an external setting circuit.

According to a fourth aspect of the present invention, a rectifier for converting an AC voltage of a commercial power supply to a DC voltage and supplying the same to an inverter and a storage battery, an inverter for converting a DC voltage to an AC voltage, a storage battery for supplying a DC voltage to the inverter, and a commercial power supply Uninterruptible power supply device having a commercial power supply monitoring circuit that monitors the AC voltage of the power supply, a circuit that monitors the depth of discharge of the storage battery, and a power supply switch that switches between power supply from the commercial power supply to the load and power supply from the inverter to the load In the case where it is determined by the circuit for monitoring the depth of discharge of the storage battery that the depth of discharge of the storage battery is higher than the reference value, a signal for switching from the online system to the offline system is output to the inverter and the power supply switch, and If it is determined that the depth of discharge is lower than the reference value, turn off the inverter and power switch. It is characterized by having a power supply switching control unit for outputting a signal for switching from the in-system on-line mode.

In a fifth aspect of the present invention, the power supply switching control unit according to the fourth aspect is characterized in that the reference value of the depth of discharge can be set by an external setting circuit during the monitoring period of the storage battery.

According to a sixth aspect of the present invention, a rectifier for converting an AC voltage of a commercial power supply to a DC voltage and supplying it to an inverter and a storage battery, an inverter for converting a DC voltage to an AC voltage, a storage battery for supplying a DC voltage to the inverter, and a commercial power supply Uninterruptible power supply device having a commercial power supply monitoring circuit that monitors the AC voltage of the power supply, a circuit that monitors the depth of discharge of the storage battery, and a power supply switch that switches between power supply from the commercial power supply to the load and power supply from the inverter to the load In the case where the number of occurrences of voltage abnormalities of the commercial power supply during the monitoring period set in advance is larger than a predetermined reference value, and the circuit for monitoring the depth of discharge of the storage battery determines that the depth of discharge of the storage battery is higher than the reference value Output a signal to the inverter and power switch to switch from the offline mode to the online mode. If the voltage abnormality of the commercial power supply during the monitoring period set in advance is smaller than the reference value and the circuit for monitoring the depth of discharge of the storage battery determines that the depth of discharge of the storage battery is higher than the reference value, the inverter and the power supply are switched. A switch is provided with a power supply switching control unit for outputting a signal for switching from an online system to an offline system.

In a seventh aspect, the power supply switching control unit according to the sixth aspect comprises: a monitoring period of the commercial power supply, a reference value of a frequency of occurrence of an abnormality in any of voltage, frequency, phase, and waveform, and a monitoring period of the storage battery. , And a reference value of the depth of discharge can be set by an external setting circuit.

[0013]

An embodiment of the present invention will be described below. FIG.
Is a block diagram of the apparatus of the present invention, and FIGS. In FIG. 1, the present invention is roughly composed of a main circuit unit 50 and a control circuit unit 51. The main circuit unit 50 is configured by a circuit that performs the following operation. That is, the AC of the commercial power supply 11 is converted into DC by the rectifier 12,
The lead storage battery 13 is charged through the shunt 7 and power is supplied to the inverter 14. And a power switch 1
Reference numeral 5 denotes a device for switching whether the power supplied to the load 16 is output by bypassing the commercial power supply 11 or output from the inverter 14 according to a signal from a power supply changeover switch control circuit 6 of a control circuit unit 51 described later. is there.

On the other hand, the control circuit section 51 is roughly divided into:
It comprises a commercial power supply monitoring section 52, a lead storage battery monitoring section 53, and a power supply switching control section 54. The commercial power supply monitoring unit 52
The circuit unit detects the voltage, frequency, waveform, and phase of the commercial power supply 11 and outputs the contents to the power supply switching control unit 54.
The frequency detection circuit 21 detects whether or not the frequency of the commercial power supply 11 is abnormal. The commercial power supply 11 is
The waveform and phase of are detected. The voltage of the commercial power supply 11 is a low voltage A detection circuit 23, an overvoltage A detection circuit 24, a low voltage B
The detection is performed by the detection circuit 25 and the overvoltage B detection circuit 26. The lead storage battery monitoring unit 53 includes a voltage detection circuit 71 for detecting the voltage of the lead storage battery 13, a shunt 7 and a current detection circuit 72 for detecting the charging / discharging current, and a discharge depth of the lead storage battery based on data measured by these circuits. Charge / discharge detection circuit 73 that calculates
It is composed of The power supply switching control unit 54 controls the switching between the offline method and the online method based on the fluctuation of the commercial power output from the commercial power monitoring unit 52 and the depth of discharge of the lead storage battery 13 output from the lead storage battery monitoring unit 53. Part. The external setting circuit 8 can manually reset the abnormality of the commercial power supply voltage, which will be described later, the monitoring period of the lead storage battery discharge depth, and the determination content.

FIG. 2 is a flowchart showing the operation of the commercial power supply monitor 52 of the present apparatus. At S11, the commercial power supply voltage is taken. In the steps after S21, the frequency and the phase difference of the AC voltage of the commercial power supply are measured. In S22, the measured frequency of the commercial power supply is (in the present embodiment,
The frequency is 50 Hz. If the frequency is within the range of 48 to 52 Hz, the frequency is determined to be normal and the procedure goes to S23. If the frequency is out of this range, the frequency is abnormal and the procedure goes to S25 and the online system is instructed. In S23, if the phase difference of the AC voltage of the commercial power supply is within 5 °, it is determined that S is normal and S
At 24, the data is stored so as to instruct the off-line method, and when the phase difference exceeds 5 °, the process proceeds to S25 as abnormal, and the data is stored so as to instruct the on-line method. The steps following S31 measure the effective value of the AC voltage of the commercial power supply,
This is the part to memorize. In S32, if the effective value of the AC voltage is less than 90V, go to S33, and if it is 90V or more, go to S34. In S33, if the effective value of the AC voltage is in the range of 80 to 90 V, the process goes to S51 and the low voltage A
And record the data. On the other hand, if the effective value of the AC voltage is out of the range of 80 to 90 V, the process goes to S52 and determines that the voltage is 80 V or less.
In S34, if the effective value of the AC voltage exceeds 110V, go to S35, and if it is 110V or less (that is, 90 to 110V), go to S36 and determine that the voltage is normal. In S35, the effective value of the AC voltage is 110 to 1
If it is within the range of 20 V, the flow goes to S53, where it is determined that the overvoltage is A, and the data is stored. On the other hand, the effective value of the AC voltage is 1
If it is out of the range of 10 to 120 V (120 V or more), S5
Then, the process goes to No. 4 and the overvoltage B is determined, and the data is stored. That is, the range of the effective value of the AC voltage is 90 V or less or 110 V or less.
In the range of V or more, the values stored in S51 to S54 are different depending on the voltage condition, but are stored in S56 so as to instruct the online method as a whole. The steps after S41 are a part for measuring the waveform of the commercial power supply. S
At 42, if the peak value of the AC voltage is less than 110V, the flow goes to S55 to determine an instantaneous power failure, and if it is 110V or more, the flow goes to S43. In S43, if the instantaneous interruption time of the voltage waveform of the commercial power supply is 2 ms (0.002 seconds) or more, go to S55 and determine an instantaneous power failure, and if less than 2 ms, go to S44 and determine that the voltage waveform is normal. I do. Therefore, when the voltage waveform is normal, the memory is stored so as to instruct the offline method in S46, and when the voltage waveform is abnormal, the memory is stored so as to instruct the online method in S56.

Next, the operation of the online / offline determination circuit 3 for switching the operation of the uninterruptible power supply in an off-line mode or an on-line mode will be described with reference to a flowchart shown in FIG. . Depending on the fluctuation of the commercial power supply 11 and the depth of discharge of the lead storage battery 13,
This is the part that determines whether to use the online method. S
After confirming the initial operation in 61, when starting the uninterruptible power supply, the offline method is set. In S62, a monitoring period of the commercial power supply 11 is set. The determination period for switching from the offline method to the online method is T
F1 and a determination period for switching from the online method to the offline method, which is the return condition, are TF2. In this embodiment, TF1 is set to one month and TF2 is set to one day.
As described above, in order to operate in the off-line mode as much as possible, the off-line mode is instructed when the voltage of the commercial power supply 11 is stabilized for about one day. S63 is a step of setting a reference value for switching between the online / offline method based on the monitoring result of the commercial power supply 11. Commercial power supply 1
Regarding the number of times of occurrence of abnormality 1, the reference value for switching from the offline method to the online method is GF1, and the reference value for the return condition for switching from the online method to the offline method is GF2. In this embodiment, GF1 is 10
Times and GF2 once. Then, from S62 and S63,
If an abnormality occurs ten times (GF1) in one month (TF1) and one or more abnormalities (GF2) occur in one day (TF2), an instruction should be given to switch from the offline method to the online method. I made it. That is, only when the abnormality of the commercial power supply 11 frequently occurs in a short period, the system is switched from the offline system to the online system.

In S64, a monitoring period of the depth of discharge of the lead storage battery is set. First, a monitoring period for switching from the offline system to the online system is TB1, and a monitoring period for switching from the online system to the offline system, which is a condition for return, is TB2. In this embodiment, TB1
Is set as one month and TB2 as one day. In S65, an online / offline method of the uninterruptible power supply and a reference value for switching are set. The reference value of the lead storage battery discharge depth for switching from the offline mode to the online mode is GB1, and the return condition for switching from the offline mode to the online mode is GB2. In this embodiment, G
B1 is 20% and GB2 is 5%. That is, it is assumed that the voltage of the commercial power supply 11 is stable in the offline method,
Even if the depth of discharge of the lead-acid battery is relatively high, there are few problems. Note that a discharge depth of 50% is a state in which half of the capacity of the lead storage battery at the time of full charge has been discharged.

In S66, the data stored in the commercial power supply monitoring circuit 52 (described in the flowchart of FIG. 2) is read. On the other hand, in S67, the data of the depth of discharge of the lead storage battery stored in the lead storage battery monitoring unit 53 is read. S68
In step (1), it is confirmed whether the vehicle is currently operating in the offline mode or the online mode. If the system is operating in the offline mode, the procedure goes to step S71. If the apparatus is operating in the online mode, the procedure goes to step S81. In S71, the commercial power source 1
It is determined whether or not the voltage fluctuation of 1 and the depth of discharge of the lead storage battery are within the range of the set reference value, that is, whether or not it is necessary to switch from the offline method to the online method. On the other hand, in S81, it is determined whether the voltage fluctuation of the commercial power supply 11 and the depth of discharge of the lead storage battery are within the range of the set reference value, that is, whether it is necessary to switch from the online system to the offline system. From these judgment results,
An offline method is selected in S72, and an online method is selected in S82. When switching the output system of the uninterruptible power supply, a signal to that effect is output to the inverter control circuit 5 and the power supply changeover switch control circuit 6, and the process ends. The setting values of the monitoring period of the commercial power supply monitoring circuit 52 and the storage battery monitoring circuit 53, the number of occurrences of the abnormality, the depth of discharge, and the like will be described later.
It is also possible to reset using the setting circuit 8 such as an external switch.

[0019]

As described above, the uninterruptible power supply according to the present invention measures the number of fluctuations of the AC voltage of the commercial power supply or the depth of discharge of the storage battery, and compares the measured value with a preset judgment value to perform the offline method. The system automatically switches between the power supply of the on-line system and the system. In addition, commercial power supply 1
Since the on-line / off-line method can be automatically switched in accordance with the situation (1), it is excellent in that it has high versatility and reliability, and that it is not necessary to check the commercial power supply environment in advance.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an uninterruptible power supply according to the present invention.

FIG. 2 is a flowchart of an example of the present invention.

FIG. 3 is a flowchart of the present invention.

FIG. 4 is a block diagram showing an uninterruptible power supply according to the present invention.

[Explanation of symbols]

3: Online / offline determination circuit 4: Memory,
5: Inverter control circuit, 6: Power supply switch control circuit, 7: Shunt, 8: External setting circuit, 11: Commercial power supply, 12: Rectifier, 13: Lead storage battery, 14: Inverter, 15: Power supply switch, 16: load,
21: frequency detection circuit, 22: waveform detection circuit, 2
3: Low voltage A detection circuit, 24: Overvoltage A detection circuit, 2
5: low voltage B detection circuit, 26: overvoltage B detection circuit, 5
0: main circuit section, 51: control circuit section, 52: commercial power supply monitoring section, 53: lead storage battery monitoring section, 54: power supply switching control section, 71: voltage detection circuit, 72: current detection circuit, 7
3: Charge / discharge detection circuit

Claims (7)

[Claims] A rectifier that converts an AC voltage of a commercial power supply to a DC voltage and supplies the DC voltage to an inverter and a storage battery, an inverter that converts the DC voltage to an AC voltage, a storage battery that supplies a DC voltage to the inverter, and an AC voltage of the commercial power supply. In an uninterruptible power supply having a monitoring circuit for a commercial power supply, a power supply switch for switching between a power supply from a commercial power supply to a load and a power supply from an inverter to a load, a voltage abnormality of a commercial power supply during a preset monitoring period. If the number of occurrences is greater than a predetermined reference value, the inverter and the power supply switch are switched from a continuous commercial power supply system (hereinafter, referred to as an offline system) for supplying commercial power to the load, and a continuous supply system for supplying the output of the inverter. Outputs a signal to switch to the inverter power supply method (hereinafter referred to as online method) and sets it in advance An uninterruptible power supply having a power switching control unit for outputting a signal for switching from an online mode to an offline mode to the inverter and the power switch when the voltage abnormality of the commercial power during the monitoring period is smaller than the reference value. Power supply. 2. The power supply switching control unit according to claim 1, wherein when the frequency of occurrence of abnormality in the frequency, phase, and waveform of the commercial power supply is larger than a predetermined reference value in a monitoring period set in advance.
A signal for switching from the off-line system to the on-line system is output to the inverter and the power supply changeover switch, and when the frequency of the commercial power supply, the phase, and the number of occurrences of the waveform abnormality are smaller than a predetermined reference value in a monitoring period set in advance, 2. The uninterruptible power supply according to claim 1, wherein a signal for switching from an online mode to an offline mode is output to the inverter and the power switch. 3. The power supply switching control unit according to claim 1, wherein a monitoring period of the commercial power supply and any one of a voltage, a frequency, a phase, and a waveform are determined.
3. The method according to claim 1, wherein a reference value of the number of occurrences of the abnormality can be set by an external setting circuit.
The uninterruptible power supply as described. 4. A rectifier that converts an AC voltage of a commercial power supply to a DC voltage and supplies the DC voltage to an inverter and a storage battery, an inverter that converts the DC voltage to an AC voltage, a storage battery that supplies a DC voltage to the inverter, and an AC voltage of the commercial power supply. An uninterruptible power supply having a commercial power supply monitoring circuit for monitoring, a circuit for monitoring the depth of discharge of the storage battery, and a power supply switch for switching between power supply from the commercial power supply to the load and power supply from the inverter to the load; If the circuit that monitors the depth of discharge of the storage battery determines that the depth of discharge of the storage battery is higher than the reference value, a signal for switching from the online mode to the offline mode is output to the inverter and the power switch, and the discharge depth of the storage battery is set to the reference value. If it is determined that the value is lower than the value, the inverter and power switch are turned off from the offline mode. Uninterruptible power supply, characterized in that it comprises a power supply switching control unit for outputting a signal for switching the line system. 5. The uninterruptible power supply according to claim 4, wherein the power supply switching control unit can set a reference value of a discharge depth during a monitoring period of the storage battery by an external setting circuit. 6. A rectifier for converting an AC voltage of a commercial power supply to a DC voltage to supply the inverter and a storage battery, an inverter for converting the DC voltage to an AC voltage, a storage battery for supplying a DC voltage to the inverter, and an AC voltage of the commercial power supply. Set in advance in an uninterruptible power supply having a commercial power supply monitoring circuit for monitoring, a circuit for monitoring the depth of discharge of the storage battery, and a power supply switch for switching between power supply from the commercial power supply to the load and power supply from the inverter to the load. If the number of occurrences of abnormal voltage of the commercial power supply during the monitoring period is larger than a predetermined reference value, and the circuit for monitoring the depth of discharge of the storage battery determines that the depth of discharge of the storage battery is higher than the reference value, the inverter Output the signal to switch from the offline mode to the online mode to the power switch and set in advance If the voltage abnormality of the commercial power supply during the monitoring period is smaller than the reference value, and the circuit for monitoring the depth of discharge of the storage battery determines that the depth of discharge of the storage battery is higher than the reference value, the inverter and the power supply switch are switched. An uninterruptible power supply device comprising a power supply switching control unit for outputting a signal for switching from an online method to an offline method. 7. The power supply switching control unit according to claim 1, wherein a reference value of a frequency of occurrence of an abnormality in any of a voltage, a frequency, a phase, and a waveform, a monitoring period of a storage battery, and a reference value of a depth of discharge. 7. The uninterruptible power supply according to claim 6, wherein the power can be set by an external setting circuit.