JPS59185168A - Control power source circuit of power converter - Google Patents

Abstract

PURPOSE:To improve the safety by providing a voltage detector of lower set value than an overvoltage detector in a power source circuit having a chopper for operating a controller at instantaneous power interupting time, and opening an AC side switch. CONSTITUTION:An AC motor Sm is driven by a power converter P, a control voltage is formed through choppers Q1, Q2, and a diode D1 for controlling the induced voltage of an idle rotation of the motor SM by rectifiers RF1, AVR at instantaneous power interrupting time, an overvoltage is detected by a Zener diode ZD1 to conduct a thyristor TH1, and protected by the fusion of a fuse EF. On the other hand, a voltage detector ISD set at the lower set value than the ZD1 is provided, an AC side magnet switch MC is opened by the operation, and the operation of the AVR is locked. Accordingly, the protection is performed in double, thereby preventing the trouble from increasing to accelerate the recovery.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a control power supply circuit for a power conversion device, and particularly to a protection circuit that protects the control power supply circuit from overvoltage that occurs during a momentary power outage of a commercial power supply.

As a control source for uninterruptible power supplies, various inverters, non-commutator-less power converters, etc., for example, as shown in Figure 1, normally the commercial power supply is connected to transformers TR, rectifiers RF, etc.
, to the control power supply circuit ae through
There is a system in which the induction force is supplied to the control power supply circuit O8 via a transformer TR and a rectifier RF.

FIG. 2 shows a commercial IIf which is a part of the control power supply circuit aS.
This figure shows an example of a control power supply circuit that obtains a desired control power supply during a momentary power outage of the power source. That is, a transformer TR transforms (steps down) the induced voltage of the AC motor EIM.

The rectifier RF is connected to the secondary side of the rectifier through the fuse EF.

is connected to the output side of the capacitor C3 and the chopper, for example, the Darlington connected transistor Q+eQ,
is connected. The output side of the chopper is connected to a lever L1 capacitor C1, etc., so that a smooth DC voltage can be obtained. An automatic voltage control unit AVR is connected to the transistor Q, whereby the voltage of a control power supply circuit that controls the power converter is controlled to a constant hidden pressure. The chopper output voltage is taken out as a temporary control power supply voltage through the diode D, and the operation of the II force transformer FT can be continued even in the case of an instantaneous stoppage of the commercial power source.

In addition, a thyristor TH for overvoltage protection is connected between the output terminals, and is turned on by a signal from an overvoltage detection circuit consisting of a Zener diode ZD, etc. ing.

In such a power supply circuit, an abnormality in the control section or transistor Q1. Q! If an overvoltage occurs due to damage to the converter, it is detected by a detection circuit consisting of a Zener diode ZD, and the thyristor TH turns on, shorting the output terminal, causing the abnormal voltage to spread to the control system that controls the converter. In addition to preventing the city from doing so, Hughes BP
The control power circuit is immediately cut off by the melting. In other words, it is possible to minimize overpressure.

However, in such a configuration, the thyristor TH.

Since the transistors Q+ and Q4 are completely short-circuited, the overcurrent at the time of short-circuiting may damage transistors Q+ and Q4, and there is a serious conflict between the fuse's blowing current, the rise rate of the fault current, and the overcurrent withstand value of the transistor. This is difficult, and as a result, in conventional circuits, the transistors are destroyed by heat, and it is necessary to convert the transistors in addition to the fuse IiF, which takes time to recover.

Another problem is that it is not clear whether the control power supply circuit is normal or abnormal.

The present invention has been made in consideration of the above points, and includes a voltage detection circuit that has a set value lower than the set voltage of the overvoltage detection circuit made of a Zener diode, etc., and uses the detection signal to trigger a magnetic switch inserted on the AC side. It has a configuration that opens the circuit, lights up the indicator light, and locks the output of the automatic voltage control section. Furthermore, by connecting a resistor that also serves as current suppression and turn-on operation detection in series with the thyristor for overvoltage protection, overvoltage protection and abnormality detection are achieved. It is an object of the present invention to provide a control source circuit for a power converter device that is accurate and can be quickly updated.

Hereinafter, the present invention will be explained in detail based on illustrated embodiments.

FIG. 3 shows an embodiment of the present invention, in which when the commercial power source is normal, the SM is powered by an AC power source driven by the output of the power converter FT. 10 machines, TR is a transformer, M
O is a magnetic switch inserted on the secondary side of this transformer TR, IP is a high speed fuse, RF is a rectifier, C
1 and 0. is the % capacitor to extract the desired control pressure, Q and Q are the transistors, L is the reactor,
zD is a Zener diode constituting an overvoltage detection circuit, DI is a diode, TH is a thyristor for overvoltage protection, and a resistor R is connected in series with the thyristor TH, and the input side of the rectifier RF. Conventionally, a magnetic switch MC is inserted in the
It is different from

AVR is an automatic voltage control section of the chopper, and the difference between the set voltage of the pressure setting circuit VS and the detected voltage of the voltage detection circuit VD that detects the chopper output voltage is detected by an operational amplifier O.
・A, output and chopper cycle setting circuit Cp
output (chopper cycle setting signal) and operational amplifier OA
, and a transistor base drive signal corresponding to the result is extracted from the output &1lsp.

Engineering S:C is the instantaneous power outage weight abnormality detection circuit, which is set at a lower voltage (breakdown pressure of ZD) than the set voltage (Zener screw pressure of Zener diode ZD) of the floating pressure detection circuit. It has a pressure detection circuit VD, which compares the detected voltage with the chopper output voltage, and when the chopper output voltage exceeds the set value, turns on the thyristor TH, and the self I! M
A signal for locking the amplifier OA of the t-pressure control unit AVH and the transistor base drive signal is generated, and at the same time, the relay RY is driven. That is, the transistor Q4 is provided at the subsequent stage of the transistor Qll, which is turned off when the thyristor TH is turned on, and the transistor Q! (lock signal generation section) generates a lock signal and closes the subsequent transistor Q4 as a relay driver. The relay has a light emitting diode H as an indicator light.
'D are connected in parallel. Also, b contact R of relay RY
By opening Yb, the auxiliary contactor McX is excited, and contact 7
Il! The magnet switch MO is de-energized by the -J path of the a contact MOXa of the LL device MOX. That is,
When a different horse is detected, the magnet switch MO is deenergized.

The resistor R1 connected in series with the overvoltage protection thyristor TH serves both as current suppression and turn-on operation (protection operation) detection, and the voltage across it is applied between the gate and cathode of the thyristor TH. be done. Therefore,
Even when the thyristor TH is turned on, the light emitting diode H
D will light up and a message to that effect will be displayed. This lighting is caused by the thyristor TH.

The call is held by operating the reset switch SW connected in series with the call to open the circuit, and the display continues if an abnormality is detected or a protective operation is performed.

Next, the operation will be described. When the commercial power supply momentarily stops, the induced voltage of the AC im machine SM rotating due to inertia is transferred to the transformer TR.
, and then the switch MO.

It is applied to the rectifier RF via the fuse IF.

After being rectified by this rectifier RF, the voltage is controlled to a constant voltage by a chopper, and the current is smoothed by a capacitor 02, etc., and taken out via a voltage diode D1, and the voltage is controlled by the voltage diode D1. If the commercial power supply is healthy, the city power converter area PT
The output of is supplied to the transformer TR, and the chopper output voltage is generated in the same manner as described above.

However, in this case, due to the DC output voltage of the rectifier RF in Fig. 1, the diode D is in a cut-off state,
The control 1Flj source pressure is supplied from the commercial power source.

Incidentally, in either case, a chopper output voltage is generated, and this voltage is monitored by the abnormality detection circuit ISD and is taken into the automatic voltage control unit AVH.

If an overvoltage occurs due to an abnormality such as a control operation, it is first detected by the voltage detection circuit VD of the abnormality detection circuit SD, and the thyristor TH is turned on.

With this turn-on, the transistor Q is turned off and the transistor Q4 is turned on, and the lock signal locks the amplifier OA of the cutter U<pressure control section AVH and the output section BD. At the same time, relay RY is energized and its contact RY
Contactor MCX and magnetic switch M are opened by opening b.
O is deactivated. As a result of this, the input side circuit of the rectifier RF is opened, resulting in a disconnection. This abnormality detection is indicated by lighting the indicator light HD.

Further, when the overvoltage detection is delayed and the voltage exceeds the Zener' voltage of the Zener diode ZD, an overvoltage detection signal is generated in the circuit, and the thyristor TH is turned on. At this turn-on, the voltage on the load side is forcibly reduced, and at the same time, the turn-on operation is not detected by the resistor R1, and no gate signal is applied to the thyristor TH2. Therefore, the thyristor TH turns on, and due to lock 1, @
□riL oppression nMI'W 75 occurs in the AVR to turn off the transistor, and the relay RY operates to open the magnetic switch MC. When the thyristor TH is turned on, K + & (j1J
This prevents damage to the transistors Q+ and Qv, and facilitates temporary replacement after confirming an error.

As described above, according to the present invention, the voltage is set to a lower value than the set α pressure (Zener" is pressure) of the overvoltage detection circuit that applies the gate IH signal to the thyristor that shorts the output end of the instantaneous power supply circuit. A detection circuit is provided to turn on the thyristor when an abnormality is detected.It generates a lock signal to be applied to the automatic voltage control unit, and also generates a control signal for the magnetic switch inserted at the input end of the current resistor, so that the transistor can be used as a chopper switch. If it is normal, when an abnormality is detected, the heavy pressure can be quickly reduced by the chopper control operation, improving safety.Also, since a resistor is connected in series with the thyristor for shorting the output terminal, the first current As a result, the situation that leads to transistor damage and fuse blowing is avoided as much as possible, and short-term recovery becomes possible.Moreover, the voltage across the resistor is used as a turn-on operation detection signal to detect the gate of the thyristor in the abnormality detection circuit. Therefore, after forcibly reducing the heavy pressure on the load side due to a short circuit at the output end, the 9: M flow side magnetic switch immediately turns on M, thereby preventing the accident from expanding.νI
Jchi, Il (Double detection using pressure and current, so protection is ensured.Furthermore, when an abnormality is detected, an abnormality detection circuit using an indicator light is activated at the same time as the magnetic switch is controlled, and the reset operation tube is used to continue the operation.) 16, the occurrence of an abnormality is obvious at a glance and can be quickly dealt with.

[Brief explanation of the drawing]

Figure 1 shows the system of No. 1 dakawa consumption device 6? FIG. 2 is a connection diagram showing an example of a configuration of a power supply path to the A1 tunryo circuit, FIG. 2 is a connection diagram showing an example of a conventional instantaneous stop trace circuit, and FIG. 3 is a connection diagram showing a simple embodiment of the present invention. . BM-AC Amitai machine, TR, and TR, ... transformer, R
F. and RFt, rectifier, EF, fuse, MO...
・Magnetic switch, Qt~Q4...transistor,
TH, and TH,・Thyristor, AVR・・Self-resistance control unit, Engineering SD・・Momentary power failure detection circuit, z′DI・
・Zener diode, RY...Relay, VD, and VD,...'voltage detection circuit, VD...voltage setting circuit, OA+ and OA,...operational amplifier, BD...output section, SW... reset switch.

Claims (1)

[Claims] (1) In the event of a momentary power outage of the commercial power supply, the induced power on the load side is transferred to a transformer, high-speed fuse, or
A chopper that turns on and off the output of the rectifier to obtain a constant DC voltage, and a chopper that turns on and off the output of the rectifier, and a chopper that turns on and off the output of the rectifier. A magnet switch inserted into the input terminal of the rectifier, a thyristor connected between the output terminal of the control power supply circuit including the above-mentioned chotsunoku when an overvoltage occurs, and a DC control circuit connected in series with the thyristor. an overvoltage detection circuit that applies a gate signal to the thyristor when an overvoltage occurs; a voltage detection circuit that has a set value lower than the set voltage of the overvoltage detection circuit; A control thyristor that uses a circuit detection signal and a turn-on operation detection signal generated in the resistor as a gate signal, a lock signal generating section that provides a lock signal to the automatic voltage control section of the chopper when the thyristor is turned on, an auxiliary relay, and the control. A relay drive circuit that drives the relay when the control thyristor is turned on, an indicator light that displays an abnormality in conjunction with the relay, a reset switch that turns off the control thyristor, and an abnormality detection circuit that detects the abnormality. A control power supply circuit for a power conversion device, comprising a switch control circuit that controls the opening and closing operation of a front S magnetic switch in response to a relay operation of a detection circuit.