JPS60226776A - Converter - Google Patents

Abstract

PURPOSE:To rapidly reset by detecting the nonconductive state of an AC power source, and producing a reset signal when becoming a conductive state after the prescribed time from when becoming the nonconductive state to reset control means. CONSTITUTION:If a malfunction occurs when an AC power source Va is turned ON, charge is stored in a smoothing condenser 1b and an inverter 1c is operated, the power source Va is turned OFF and again reset. If the power source Va is turned OFF during the prescribed time at this time, a trigger signal of a monostable multivibrator 17 is not input, and when the power source Va is reset, an output signal is converted from H level to L level. A monostable multivibrator 20 generates a reset signal E only during a period set by a resistor 18 and a capacitor 19 to reset an inverter controller 3.

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention relates to a conversion device that converts an AC power source into a DC power source using a forward converter and converts it into variable voltage and variable frequency output using an inverse converter, and in particular a control circuit that converts an AC power source into a DC power source using a forward converter and converts the AC power source into a variable voltage and variable frequency output using an inverse converter. The present invention relates to a conversion device that is reset by intermittent power supply.

[Prior art]

FIG. 1 is a block diagram showing a schematic configuration of a conventional conversion device. In the figure, 1 is an inverter main circuit unit as a conversion means for converting AC power supply Va to variable voltage, variable frequency output vb, a forward converter 1a, and a flat inertia capacitor lb.
, and an inverse converter 1c. Further, 2 is a DC/DC converter, 3 is a control circuit of the inverter main circuit section 1), the DC/DC converter 2 detects the inverter DC section potential VC of the inverter main circuit section 1, and converts it into a predetermined DC voltage. It is converted into Vd and supplied as a power input to the control circuit 3. Note that the control circuit 3 is configured as shown in FIG. In the figure, 3a is a software acceleration/deceleration processing unit that makes the inverter output frequency fo follow the speed command f1 at a predetermined time, and 3b is a voltage vO corresponding to the output frequency fO.
The V/f converter 3c determines the output frequency fo.
, based on the output voltage vO, generates the track/sysmet 2 signal fp of the impark main circuit section 1, and adjusts the output frequency fo.
, a PWM signal generator that determines the switching mode of the transistor under the conditions of output voltage vO. Furthermore, 3d
is the abnormal state detection circuit for the load of this device, and the current (not shown) is ! An abnormal state is detected based on the detected value from the voltage or power level detector, and the PWM signal generator 3c is controlled to stop the inverter operation of this device.

The operation of the conventional example configured as above will be explained next.

When the AC power supply Va is supplied, the inverter DC section potential V
Since c rises to a level proportional to AC power supply Va,
The DC-DC converter 2 supplies a power supply Vd to the inverter control circuit 3. Therefore, if the AC power source Va is supplied, the power source Vd of the inverter control circuit 3 is secured, and the inverter operation becomes possible. Next, using the time chart shown in FIG. 7, the operation when the AC power source is turned off for an arbitrary time (T off ) will be described. At time t1, AC power supply V
When a is turned off, the inverter DC section potential Vc begins to fall, but since charge is accumulated in the Hirayui capacitor 1b, the voltage is determined by the control power supply load at that time, the inverter load, and the capacitance of the Hirayui capacitor 1b. It decays due to the decay time constant.

Therefore, the time required for the power supply Vd of the inverter control circuit 3 to attenuate to an unsecured level will vary depending on the above-mentioned load conditions at that time.

On the other hand, when this device is driving a certain load, for example, an overcurrent
When an abnormal state such as overvoltage occurs, the abnormal state detection circuit 3d as a protection circuit shown in FIG. 2 operates to stop the inverter operation and protect it. At this time, the power supply Vd continues to be supplied to the control circuit 3, and the protected state continues. Therefore, in order to restart the inverter operation from this stopped state, it is necessary to reset the control 1 path 3 using the reset circuit shown in FIG. 3 to release the protected state. The above cancellation is normally performed by resetting the entire inverter control circuit 3 and returning it to a complete initial state. This inverter control circuit 3
For resetting, there is a reset that is automatically applied when the power supply Vd rises, and a reset that is applied automatically when the power supply Vd is secured.
There are two types of reset: external operation or external signal. If it becomes necessary to use the former reset method for some reason during operation, the conventional device turns off the AC power supply Va once, since the attenuation state of the power supply Vd differs depending on the load conditions as described above. A sufficient amount of time must be ensured to turn it on again, and this time also varies depending on the load conditions, making it impossible to perform a quick reset operation.

Furthermore, the above-mentioned reset operation in the conventional example will be explained with reference to FIGS. 3 and 4. FIG. 3 is a conventional reset circuit, and FIG. 4 is a time chart explaining its operation. That is, the reset signal B is generated in the period To until the output A, which is delayed from the rise of the power supply Vd by the time constant of CR set by the resistor 4 and the capacitor 5, reaches the threshold level vL of the Inverter and Talo. Cow cheating. Therefore, in order to generate the reset signal B in this circuit, it is necessary to sufficiently attenuate the power supply Vd and then raise it again. However, in this device which supplies the power supply Vd of the inverter control circuit 3 from the inverter DC section via the DC-DC converter 2, the inverter DC section potential Vc and the power supply Vd have the relationship shown in FIG. 4, so the DC section potential If Vc is not sufficiently attenuated, the power supply Vd will not be attenuated, and as shown in the figure, if the power off time is long (T1), a reset will be applied, but if the power off time is short (T2), a reset will not be applied even if the power is turned on again. I couldn't. Therefore, in the conventional device, it is necessary to secure an off time for the AC power source Va until the inverter DC section potential Vc is sufficiently attenuated, and since that time varies depending on the load condition, it is necessary to ensure the time required for resetting even under the lightest load condition. This has the disadvantage that it is not suitable for quick reset operations.

[Summary of the invention]

The present invention includes a reset signal generating means that detects a non-energized state of the AC power source and outputs a reset signal to reset the control means when the AC power supply becomes energized after a predetermined period of time after the AC power supply becomes non-energized. The present invention is intended to eliminate the above-mentioned drawbacks, and will be explained in detail below using examples.

[Embodiments of the invention]

Fifth Expansion This is a block diagram showing a schematic configuration of an embodiment of the converting device according to the present invention, and the same parts as in FIG. In the figure, 10 insulates the supply state of AC power Va to the inverter main circuit section 1;
The power supply detector 11 for detecting is a reset signal generator that receives the output C of the power supply detector 10 and generates a reset signal when the AC power supply Va is turned off for a predetermined period or more and then turned on again. The reset signal generator 10 and the reset signal generator 11 constitute a reset signal generating means 12. FIG. 6 is a circuit diagram showing an embodiment of the reset signal generating means 12. In the figure, a power supply detector 10 includes a single-phase single-wave rectifier 13 connected between R and S phases of an AC power source Va, and an optical insulating element 14 that detects the supply state of the AC power source Va based on its half-wave rectified signal. output signal C shown in FIG.
Output. The reset signal generator 11 receives the above output signal C as an input, uses the change from the ■ level to the L level as a trigger, and outputs a monostable signal at the H level for a period in which the power is set by the resistor 15 and the capacitor 16. It consists of a multivibrator 17 and a monostable multivibrator 20 which inputs the above signal and outputs a reset signal E for a period set by a resistor 18 and a capacitor 19.

Next, the operation of this embodiment configured as described above will be explained with reference to the time chart shown in FIG. 7.

When the AC power supply V'a is turned on, charge is accumulated in the Hirayoshi capacitor 1b of the main circuit DC section, the power supply Vd is supplied to the inverter control circuit 3 through the DC/DC converter 2, and the inverter operation continues. Assume that an abnormality occurs and the inverter operation is stopped.

At this time, it is necessary to turn off the AC power supply Vh and reset the inverter control circuit 3. First, at time t1, the AC power supply Va is turned off, and the Toff time is set to be sufficiently longer than the half cycle time of the AC power supply Va, and also longer than the inverter operation continuation time during a momentary power outage, which is the design target of this device. Assume that it is returned again later at t2.

At this time, as shown in FIG. 7, the inverter DC section potential Vc
Even at a sufficient level without attenuation, it is possible to reset by the operation described below. That is, AC power supply V
When a is being supplied, the seventh
As the output signal C shown in the figure, H level and t level are repeatedly output in the same cycle as the AC power supply Va, but in the monostable multivibrator 17 at the front stage of the reset signal generation circuit 11, the resistor 15 and capacitor 16 Since the pulse width of the output signal is set to be longer than the half cycle of the AC power supply Va, the period corresponding to the non-continuity of the power supply half cycle is insensitive and does not pose a problem for continuing normal operation.

Here, if the AC power supply Va is turned off for a predetermined time or more for the purpose of reset operation, the monostable multivibrator 17
The trigger is not input, and the output signal changes from the H level to the L level at the set pulse width tll. When the AC power supply V& is restored at time t2 after the Toff time has elapsed, the output signal C changes from the H level to the L level, and accordingly, the output signal C changes from the L level to the H level. Therefore, the output signal E of the monostable multivibrator 18 changes from L level to H level at this time, and the resistor 1
8 and a capacitor 19, a reset signal E of H level is generated for a period set by the capacitor 19. In this way, in the inverter device according to this embodiment, the inverter control circuit 3 is reset regardless of the heavy load condition when the AC power is turned off.
Inverter operation can be started again.

In the above embodiment, the single-phase half-wave rectifier circuit 13 and the optical insulation element 14 were used in the power supply detector 10, but single-phase full-wave, three-phase half-wave, three-phase full-wave, etc. rectifier circuits and other Insulating means may also be used. Furthermore, although the reset signal generation circuit 11 is composed of monostable multivibrators 17 and 20, other time management means such as a counter may be used.

〔Effect of the invention〕

As explained above, according to the converter according to the present invention, a non-conducting state of alternating current is detected, and when a predetermined period of time after the non-conducting state becomes energized, a reset signal is outputted to reset the control means. By providing a reset signal generating means to

[Brief explanation of the drawing]

1 and 2 are block diagrams showing an example of a conventional conversion device, FIG. 3 is a circuit diagram of the reset circuit, FIG. 4 is a time chart showing the reset operation, and FIGS. 5 and 6 are A block diagram and a circuit diagram showing one embodiment of the conversion device according to the present invention, and FIG. 7 are time charts showing the operations of the conventional example and the present embodiment. DESCRIPTION OF SYMBOLS 1... Inverter main circuit section, 2... DC-DC converter, 3... Inverter control circuit, 10... Power supply detector, 11... Reset signal generator, 12... elJ set signal generation In the figures, the same reference numerals are used for the same or corresponding parts. Figure 6 Figure 7 Procedural amendment (self-initiation 2, invention name conversion device 3, relationship with the case of the person making the amendment Patent applicant address 2-2-3 Marunouchi, Chiyoda-ku, Tokyo Name)
(601) Mitsubishi Electric Corporation Representative Hitoshi Katayama 4, Agent address Mitsubishi Electric Corporation 5, 2-2-3 Marunouchi, Chiyoda-ku, Tokyo, Column for detailed explanation of the invention subject to amendment. 6. Contents of correction (11 Specification, page 2, line 10, "Detect VC" is corrected to "rVc is input"). (2) Page 2, line 19 of the same document ” has been corrected to read “ransistor drive.” (3) In the same book, page 6, line 4, “even if re-thrown” has been changed to “
Even if it is re-injected,” he corrected. (4) On page 7, line 13 of the same book, replace the phrase “single phase single wave” with “
Corrected as "single-phase half-wave."that's all

Claims (1)

[Claims] A conversion means for converting AC power into DC and converting the DC into a variable voltage, variable frequency output, a control means for controlling the conversion means, and a DC for supplying the DC of the conversion means as a power source for the control means. a converting device comprising a converting means, which detects a non-energized state of the AC power source, and outputs a reset signal when the AC power source becomes energized after a predetermined period of time after the AC power source becomes a non-energized state; 1. A conversion device comprising reset signal generating means for resetting.