JPS5863038A - No-break power source - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a DC switch type uninterruptible power supply device, and particularly includes a double-headed conversion section dedicated to floating charge and equal charge, and provides DC power to a battery and a reverse conversion section using a DC chopper circuit. The present invention aims to provide an uninterruptible power supply that controls the

As an uninterruptible power supply, the forward conversion section is configured with a thyristor rectifier, and the forward conversion section is used to charge the battery in a floating manner. It is well known that there is a DC switch type in which a dedicated charger is installed and the desired DC power is supplied to the inverter without momentary interruption through a DC switch circuit in the event of an abnormality in the commercial frequency power supply. It is. In the former floating charging method, the glans conversion section is configured with a thyristor rectifier, so it can protect the element group from overvoltage, and can also protect against accidents caused by the gate circuit, such as erroneous firing or gate signal failure. , the equipment itself is required to be extremely reliable, which inevitably makes the circuit configuration complex and extremely uneconomical.
On the other hand, the latter DC switch type uses a diode rectifier in the forward conversion section, which solves the initial drawback of floating charging voltage values, making it an excellent uninterruptible power supply in this respect. . However, a dedicated charger for charging the battery is required, and as this battery charger is well-known, it is composed of an isolation transformer and a thyristor rectifier that is a pure bridge connection of a thyristor, so the uninterruptible power supply itself is large. In addition, it is very expensive in terms of cost, which offsets the cost advantage of using a diode rectifier as the forward conversion section. The details will be explained based on the following.

In the same embodiment, reference numeral 1 denotes a first forward conversion section constructed by connecting diodes in a bridge connection, and this forward conversion section is dedicated to charging the battery 5 evenly, and reference numeral 2 denotes a first forward conversion section constructed by connecting diodes in a bridge connection. This forward converter 2 floats and charges the battery 5, and at the same time supplies the rectified output of commercial frequency AC power to the inverse converter during steady state. It is sufficient that the capacity is required for floating charging, and the 10th forward conversion unit 1
e3 is a DC chopper circuit, and although it is not shown in the figure, it can include power transistors, gate turn-off thyristors, -shell structure thyristors, and other switching elements. Application: 11, K controls the ON-OFF cycle of this switching element, and K controls the average value of the DC power supplied to the battery, and 4 is the inverter, which controls the average value of the DC power supplied to the battery. 6 is a DC switch circuit, and although this switch circuit is not shown, it includes a main thyristor for guiding the desired DC power to the inverter, and a main thyristor for forcing this main thyristor. It consists of an auxiliary thyristor for arc extinguishing, a commutating capacitor, a commutating reactor, a commutating diode, and a forced arc extinguishing circuit consisting of a charging current suppressing resistor. 7 is a DC filter circuit consisting of DC reactor L and smoothing capacitor 2.7, and 8
9 is an inverter converter configured by connecting thyristors in a pure bridge and converts DC power back into AC power; 9 is a flywheel diode for circulating the energy of the DC reactor to the battery 5 when the DC chopper circuit is OFF;
10 is a step-up transformer that steps up the commercial frequency power supply voltage to an appropriate value.

11 is a voltage detection transformer for extracting a commercial frequency power supply voltage; 12 is a voltage detection circuit for extracting a desired power supply voltage from between the terminals of a rectifier with bridge-connected diodes; 13
14 is a current detection circuit for detecting the DC output current of the DC switch circuit 6, and 15 is a comparator for extracting the voltage between the terminals of the DC main circuit. In the converter, 16 is a voltage setting device for setting the reference value of DC voltage, 17 is a comparison circuit for comparing the voltage setting command signal and the voltage detection signal, and 18
is a voltage control amplifier to temporarily amplify the error voltage, and 1
9 is a V converter circuit for obtaining a pulse frequency proportional to the voltage; originally it was a monomultiplier that outputs a rectangular wave of a predetermined width based on the input pulse signal; 21 is a voltage between the terminals of the DC switch circuit 6; , η is an NO gate, 26 is an OR gate, 24 and δ are AND gates, 26 is a first gate circuit for triggering the switching element of the chopper circuit, and 27 is the second thyristor for gate driving the main thyristor of the DC switch circuit 6.
This is a gate circuit.

To describe the operation of this embodiment configured as above, the commercial frequency power supply voltage is monitored through the path of transformer 11 → voltage detection circuit 12 → comparator V-16, and when the commercial frequency power supply is healthy, , the first and the twentieth forward converters 1 and 2 convert the commercial frequency AC input power into DC power, and the battery 5 has a power of 300
If it is an M system, the battery is charged evenly to approximately the same level as before, and the DC output of the second forward converter 2 is supplied to the inverse converter 8 to be inversely converted to AC power, which supplies constant voltage and constant frequency power to the load. For example, the comparison circuit 17 compares the reference value set by the voltage setting device 16 with the level of the voltage detection signal of the main circuit converted to a DC level, and calculates the error voltage. If this error occurs, the voltage control amplifier 18 amplifies the error 7i, EE, and the amplified error voltage is converted into a digital pulse signal by the ψ conversion circuit 19.
This pulse signal is added to the monomulti 20 to output a rectangular wave of a predetermined width every time a pulse signal group is input, and this rectangular wave signal is guided to the second AND gate 25. In parallel with this operation, , if the commercial frequency power supply is healthy, the output of "1" from the comparator 13 is the first AND gate', -
j) 24 K is added and the second gate circuit 2
7rc is applied, and this gate circuit 27 maintains a cut-off state. Therefore, the voltage detection circuit 21 detects that the DC switch circuit 6 is in the OFF state by detecting the voltage between the current detection signal detected through the current detection circuit 14→NOT gate 22 path and the voltage across the main thyristor of the DC switch circuit 6. The determination is made by taking the logical sum with the detected voltage detection signal, and the logical sum output "1" of the OR gate is converted to the first AND gate) 24 K
Guide. This first AND gate 24 opens the gate because an AND condition is established between the input logical sum output "1" and the "moon signal" which indicates that the commercial frequency is healthy. A second AND gate 25 calculates the AND of the output of the monomulti 20 and the output from the monomulti 20, and the rectangular wave signal output from the monomulti 20 is output to the second AND gate 2.
5, the gate is opened every time an input signal is input to the DC chopper circuit 3, and the switching element of the DC chopper circuit 3 is gate-driven through the 26 gate circuits 26 to control the ON-OFF cycle of the switching element. 5
It controls the average value of the DC voltage supplied to the load and maintains the voltage supplied to the load as per the command value. It should be noted that the frequency at which power is supplied to the load is determined by the inverse converter 8 as is well known.
Needless to say, this is controlled via a frequency control system (not shown).Next, we will discuss the operation when the commercial frequency power supply is abnormal.First, for some reason, the commercial frequency power supply voltage drops significantly and the power supply voltage When the value becomes lower than the reference value, the comparator 13 outputs a second signal indicating that the commercial frequency power supply is abnormal.
K is applied to the gate circuit 27 of this gate circuit 27.
The DC switch circuit 60 (not shown) is ignited to supply the desired DC power from the battery 5 to the inverter 8 to continue the prescribed power supply operation, and the above-mentioned "law output" of the comparator 13 is switched to the first AND game) 24
K is applied to this gate circuit 24, and the other input signal is an OR gate 2 indicating that the DC switch circuit 6 has operated.
Since the "mouth" output of 3 is applied, the logical product condition does not hold for these two input signals, and the AND gate of 24 is closed. In this way, when the AND gate of 24 is closed, the second
Since the AND gate 25 also closes its gate, the first gate circuit 26 is cut off and the DC chopper circuit 3 is also turned off instantaneously, and the DC outputs of the first and second forward converters 1 and 2 are cut off. Ru. As is clear from this operation explanation, in the case of a power outage mode in which the power supply voltage of the commercial frequency power supply suddenly drops for some reason and the DC switch circuit 6 operates, even if the power supply voltage value of the commercial frequency power supply is In this case, the DC chopper circuit 3 is automatically turned off, so the positive side diode of the forward conversion section 1 - the chopper circuit 3 →
A short-circuit loop of DC reactor 4 → DC switch circuit 6 → negative diode of forward converter 1 → commercial frequency power supply is not formed, and the overcurrent causes forward converter 1 and chopper circuit 3. The elements of the inverse transformer 8 are never permanently destroyed. Note that in the event of a power outage in the commercial frequency power supply, the period in which the DC switch circuit 6 operates to supply the desired DC power to the inverter 8 is as follows, in exactly the same manner as the operation mode when the power supply voltage drops as described above. The chopper circuit 3 never becomes conductive, and the desired AC power is supplied through the battery 5 → DC switch circuit 6 → DC filter circuit 7 → inverse converter 8 → load path, and when the commercial frequency power is restored, Comparator 13 → second gate circuit 27
The main thyristor (not shown) of the DC switch circuit 60 is forcibly extinguished through the red path of the DC switch circuit 6, and the DC current flowing to the inverse converter 8 becomes zero, or the A- of the main thyristor of the DC switch circuit 6 is turned off.
Under the 50R condition that there is a voltage between This is to return the battery 5 to floating charging or even steady mode of equal charging.

As described above, in the present invention, a forward converting section that supplies a voltage corresponding to a floating charging voltage value and a forward converting section that supplies a voltage corresponding to an equal charging voltage value are respectively provided, and the DC voltage is Predetermined control is performed through the chopper circuit, and the circuit is configured so that the chopper circuit will not be turned on while the DC switch circuit is operating in the event of an abnormality in the commercial frequency power supply, ensuring that unexpected accidents will never occur during a power outage. Since it has been designed to prevent this from occurring, it has various effects as shown below.

(2) Predetermined voltage control is performed by chopper control, and since the frequency of the chopper is increased, the DC intermediate circuit load can be reduced, and the uninterruptible power supply itself can be downsized.

■ Since the DC switch circuit and the chopper circuit are interlocked with each other, a short circuit current will never flow during a transition to power outage mode or steady mode. Furthermore, since it is possible to reduce the number of AND gates in the embodiment to one,
It is possible to further simplify the circuit configuration and provide an extremely economical uninterruptible power supply.・

[Brief explanation of the drawing]

'1 Figure is a specific circuit configuration diagram showing an uninterruptible power supply according to the present invention, 1-2 is a forward conversion section, 3 is a chopper circuit, 5 is a battery, 6 is a DC switch circuit, and 8 is a reverse conversion section. Department. 12-21 is a voltage detection circuit, 13 is a comparator, 14
is a current detection circuit, 15 is a DC/l)C converter, 16
is a voltage setting device, 18 is a voltage control amplifier, 19 is a V conversion circuit, 20 is a monomulti, 22 is a NOT gate, 23
is a billion games), 24-25 is an AND gate, 26-
27 is a gate circuit.

Claims (1)

[Claims] In addition to forward converting the AC input power of a commercial frequency power supply to DC power and equally charging the battery, In addition to forward converting the AC input power of the power supply to DC power and floating charging the battery, a second forward conversion section consisting of a diode rectifier converts the battery's DC power back without interruption in the event of an abnormality in the commercial frequency power supply. a DC switch circuit that supplies the DC power to the converter, an inverse converter that reversely converts DC power to AC power, and chopper control of the DC power output from the first and second forward converters to control the average value of the DC power. Then, this DC power is converted to an inverse converter and a bar. , the chopper circuit that supplies the battery, the voltage detection signal A of the commercial frequency power supply, the signal B that detects the operating state of the DC switch circuit, the error voltage EEK between the voltage command signal and the DC voltage detection signal of the main four circuits. A logical product condition of the three quantities with the proportional pulse frequency signal C is taken, and only when this logical product condition is established, the chopper circuit is made conductive and a predetermined chopper control is performed based on the above pulse frequency signal, and the logical product is An uninterruptible power supply system characterized by comprising a control section that makes the chopper circuit non-conductive and makes the DC switch circuit conductive only when the conditions are not satisfied, thereby transitioning to a power outage mode.