JPH04183224A - Dc power supply - Google Patents

Abstract

PURPOSE:To detect instantaneous interruption of primary power supply regardless of open circuit state or short circuit state by providing a three-phase transformer for monitoring input power, a rectifying circuit for inverting AC power into DC power, a resistor for converting a current into a voltage and a circuit for comparing thus converted voltage with a reference voltage, thereby driving a thyristor. CONSTITUTION:AC input current on each line is normally detected through a three-phase transformer 20, rectified through a rectifying circuit 21 and converted through a resistor 22 into a voltage which is then compared through a comparing circuit 23 with a reference voltage thus deciding a normal operating state. Since AC input current does not flow on each line upon interruption of power supply from a primary power supply 1, the three-phase transformer 20 and the rectifying circuit 21 do not function and thereby no voltage appear across the resistor 22. Consequently, the comparing circuit 23 makes a decision of instantaneous power interruption and a signal is fed to a load 9. Upon occurrence of instantaneous power interruption under open circuit state, a signal is also fed from the comparing circuit 23 to a thyristor driving circuit 24 for driving thyristors 17, 18, 19 thus bringing each line into short-circuited state.

Description

[Detailed description of the invention] [Conventional technology] FIG. 2 is a configuration diagram of a conventional DC power supply device.

+11 is a primary source that supplies AC power, (2) is a filter circuit consisting of a choke coil and a capacitor that prevents the high frequency current of the DC power supply from flowing into the primary source, and (3) is a filter circuit that converts AC input into DC power. rectifier circuit for converting into
(4) is a control circuit for controlling the voltage of the power supplied to the load (9), and (5) is a capacitor for supplying pulsed power to the transformer (7) in conjunction with the switch operation of the transistor (6). , (6) flows into transformer (7) 1
(7) is a transformer, (8) is a rectifying and smoothing circuit that rectifies and smoothes the output of the secondary winding of transformer (7), (9) is a load, (IQ and Noto [1B is a diode that converts the AC voltage supplied from the primary power supply +11 to DC, αken and αhiro are diodes tl
l.

0 is a comparison circuit that compares the detected voltage with a reference voltage, αe is a diode d・, aυ, ([a, resistance α3゜α
This is an instantaneous interruption detection circuit consisting of a comparator circuit a$, which outputs an instantaneous interruption detection signal to the load (9).

Further, the control circuit (4) has a function of detecting the output voltage of the rectifying and smoothing circuit (8), controlling the on/off time ratio of the transistor (6), and stabilizing the output voltage. .

Here, let us consider a case where the main power supply port (-large power supply port) stops supplying power. - If the igneous source (11) has low impedance or is short-circuited and the power supply is stopped, the energy stored in the capacitor of the filter circuit (2) will be released to the low impedance primary power source (11). The voltage of each line becomes zero instantaneously, and the instantaneous interruption detection circuit ae can detect an instantaneous interruption.However, if the igneous source fil is in a high impedance, short-circuited state and the power supply is stopped.

The energy accumulated in the capacitor of the filter circuit (2) passes through the diodes αl), 11), (17J and is consumed by the resistor α1.α◆, so the energy accumulated in the capacitor of the filter circuit (2)
) If the resistance of the capacitor is <13, there will be a delay in detection time due to the CI time constant, making it impossible to detect instantaneous interruptions.

[Problem to be solved by the invention]

Since the instantaneous power failure detection circuit in the conventional DC power supply device is configured as described above, there is a problem in that it is not possible to detect the instantaneous power failure in a short time when the igneous source fil is in an open state and a momentary power failure occurs. Ta.

This invention has been made to solve such problems, and relates to a DC power supply device that can instantaneously detect a momentary power outage regardless of whether the power outage of the igneous source +11 is in an open state or a short-circuit state. It is.

[Means to solve the problem]

The DC power supply device according to the present invention includes a three-phase transformer for monitoring the input power of each line, a rectifier circuit 2υ for converting alternating current into direct current, a resistor for converting current into voltage, and a base standard. A comparison circuit @ is provided to compare the pressure, and a thyristor Q7+ is provided to extract the energy stored in the capacitor of the filter circuit (2).
, α8, ill, and a thyristor drive circuit for driving the thyristor.

[Effect]

In the DC IL source device according to the present invention, when the primary bottom source (1) momentarily breaks down, any or all of the secondary winding outputs of the three-phase transformer (1) become zero, and the momentary break occurs in the comparison circuit (to). Judging that, the thyristor (1υ.

+II, drives αl.

〔Example〕

FIG. 1 shows one embodiment of this invention, and 6. (t+~(9)
is the same as or equivalent to the conventional device described above, and ση.

a8, (II is a thyristor for extracting the energy accumulated in the capacitor of the filter circuit (2), (
1) is a 3-phase transformer for detecting the alternating current input current of the igneous source (1), (c) is a rectifier circuit for rectifying the secondary winding output of the 3-phase transformer 4, @ is a rectifier circuit Qυ c13 is a resistor for converting the rectified current into voltage, and c13 is a resistor (
c24J is a comparison circuit for comparing the DC 1 voltage converted in 2) with the reference 1 voltage, and c24J is the thyristor σD, αa, (1
9 is a thyristor drive circuit for driving these thyristors Ilη, (11, (1'i, 3-phase transformer ■,
This is an instantaneous interruption detection circuit consisting of a rectifier circuit Cυ, a resistor @, a comparator circuit @, and a thyristor drive circuit (two complements).

In the DC power supply device configured as described above.

During normal operation, the input AC current of each line is transferred to a three-phase transformer (
1) and rectified by the rectifier circuit clID.

The resistor converts the current into voltage, which is compared with a reference voltage in the comparator circuit @, and is determined to be in normal operating condition.

Next, consider the case where the power supply to the -igneous source (1+) is stopped.The AC human power '1 current no longer flows through each line, and no current is detected in the three-phase transformer (2).

Since no rectified voltage is generated in the rectifier circuit Qυ and no voltage is generated in the resistor 4, the comparison circuit (c) determines that there is an instantaneous interruption and sends a signal to the load (9). Also.

Even when the instantaneous interruption occurs in an open state, the current detected in the three-phase transformer (1) is much smaller than that during normal operation, and there is no delay in detecting the instantaneous interruption. Furthermore, when a momentary interruption occurs in the open state, in the conventional device, the energy stored in the capacitor of the filter circuit (2) is consumed by the time constant between the capacitor and the resistors 0 and 04. There is no resistance etc. that consumes energy in the circuit in the explanation tube.

The capacitor of the filter circuit (2) becomes a natural discharge.

There is a risk of electric shock if you accidentally touch it. Therefore, in the present invention, when a momentary interruption is confirmed in the comparator circuit (c), a signal is sent to the load (9) and also to the thyristor drive circuit @, and the thyristors αη, α[present],
It also has the function of eliminating the above-mentioned danger by driving α9, short-circuiting each line, and forcibly drawing out the energy stored in the capacitor in the filter circuit (2).

In the above embodiment, a three-phase transformer (to) was provided and a three-phase input was shown, but a single-phase transformer was provided.

A similar effect can be expected in a single-phase input DC power supply device by providing a single-phase rectifier circuit.

〔Effect of the invention〕

As described above, according to the present invention, since the detection circuit for detecting the input current is provided in the instantaneous interruption detection circuit of the DC power supply, it is possible to detect the instantaneous interruption of the primary power supply regardless of the open state or short-circuit state. .

At the same time, it has the effect of eliminating the risk of electric shock due to magnetization of the capacitor in the filter circuit.

[Brief explanation of drawings]

FIG. 1 is a block diagram of a DC power supply device showing one embodiment of the present invention, and FIG. 2 is a block diagram of a DC power supply device showing a conventional example. In the figure, (1) is the primary power supply, (2) is the filter circuit, and (3
). Q]) is a rectifier circuit, (4) is a control circuit, and (5) is a capacitor. (6) is a transistor, (7) is a transformer, (8) is a rectifier and smoothing circuit, (9) is a load, 0(1, +lυ, α2 is a diode, (11°(J4, @ is a resistor, αS, (T) ) is a comparison circuit, ae, cs are instantaneous interruption detection circuits, aη, +
III, +151 is a thyristor, ■ is a three-phase transformer, and 12a is a thyristor and drive circuit. Note that the same reference numerals in Figure 9 indicate the same or corresponding parts.

Claims (1)

[Claims] a control circuit that detects the voltage supplied to the load and controls the pulse width; a transistor that performs a switching operation based on the output signal of the control circuit; one end of a primary winding is connected to the collector of the transistor; a transformer having a secondary winding, a capacitor that supplies pulsed power to the transformer, a first rectifier circuit that converts AC power from a primary power source into DC, and a second rectifier circuit that rectifies the output of the transformer; a smoothing circuit that smoothes the output of the second rectifier circuit; a filter circuit that prevents high frequency current caused by the rectification by the first rectifier circuit and the switching operation of the transistor from flowing out to the primary power supply side; a thyristor connected to the power line of each phase between the primary power source and the first rectifier circuit, the cathode of which is connected to ground, and parallel to the power line of each phase between the primary power source and the first rectifier circuit; a second transformer connected to and having at least one primary and secondary winding, a third rectifier circuit for rectifying the secondary winding output of the second transformer, and an output of the third rectifier circuit; A DC power supply device comprising: a comparison circuit for comparing with a reference voltage; and a thyristor drive circuit for driving the thyristor using an output signal of the comparison circuit.