JP2010051098A - Uninterruptible power supply switching device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an uninterruptible power supply switching device that achieves sure switching at a high speed within a 1/4 cycle by maximally reducing power loss to be generated while supplying power via a contact switch during regular power supply, and also, by starting power supply from a standby-side power supply after completely separating an abnormal-side power supply at a high speed during the occurrence of an abnormality in the power supply. <P>SOLUTION: The uninterruptible power supply switching device includes: a double-throw electromagnetic contactor 6 being a change-over switch between a regular-use side AC power supply 1 and a standby-side AC power supply 2; a solenoid electromagnetic contactor 30 connected in series between a common contact of the double-throw electromagnetic contactor 6 and a load 5; a semiconductor switch 10 connected between the regular-use side AC power supply 1 and the load 5 in parallel with the double-throw electromagnetic contactor 6 and the solenoid electromagnetic contactor 30; a semiconductor switch 20 connected between the standby-side AC power supply 2 and the load 5 in parallel with the double-throw electromagnetic contactor 6 and the solenoid electromagnetic contactor 30; an abnormal-voltage detection circuit 42; and a control circuit 40 for executing control of each part. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a power supply switching device in which, when power is supplied from two AC power sources to a load, any one of the AC power sources is selected and power is supplied to the load. In both cases of automatic switching to power supply by the standby power supply in the event of an abnormality such as a power failure of the side power supply, and manual switching that switches the power supply system when both power supplies are normal, switching is extremely safe and fast The present invention relates to an uninterruptible power supply switching device.

  Since the fusion of computers (information processing) and communications has begun, information communication systems and network systems are now expanding rapidly in all fields such as industry, distribution, transportation, finance, broadcasting / communications, and security. The effects of troubles are also immeasurable. The power supply system that supports these systems is also required to be 24 hours a day, 365 days a year without interruption, and is used for commercial power outages, uninterruptible power supplies, private power generation facilities, system switching Power supply systems that efficiently combine power supply switching devices have been introduced, but recently, high-speed operation that can safely and reliably cope with power supply failure without any interruption even during the breakdown or maintenance of individual components There is a need for an uninterruptible power supply switching device (within 1/4 cycle, and therefore within 5 msec. At 50 Hz and 4.16 msec. At 60 Hz).

Under such circumstances, there are the following well-known power supply switching devices.
FIG. 10 shows an example of a generally known AC power supply switching device. As the switch, contact switches 3 and 4 such as an electromagnetic contactor are used. In some cases, a high-speed double-throw electromagnetic contactor 6 shown in FIG. 11 is used. This method has high reliability due to its simple circuit configuration, but the operation time of the magnetic contactor is as long as 20 to 50 msec. Therefore, when the power supply on the normal side is abnormal, such as when a power failure occurs, it is automatically detected and a healthy standby is performed. When switching to the side power supply, an instantaneous interruption time of 20 to 50 msec. Or more occurs in the power supply on the load side, and many load devices with an allowable instantaneous interruption time of 5 to 10 msec. There is an inconvenience of stopping or causing malfunction.

  FIG. 12 is another example of a generally known AC power supply switching device. However, since the changeover switches 7 and 8 are composed of semiconductor elements (for example, thyristors), the on / off operation time as a switch is fast, and the switch is used regularly. Depending on the method of abnormality detection (power failure detection) of the side power supply, a power supply switching time of 5 msec. Or less is possible. Further, since the other semiconductor switch is turned on after one semiconductor switch is turned off, a cross current between the two power sources can be avoided. However, since the changeover switch is a semiconductor in this method, there is a voltage drop due to an energized current, resulting in a watt loss, so that cooling of the semiconductor element becomes a problem in terms of device size and cost, and also affects the operating cost. To do. This problem is not so much a problem with a small-capacity switch up to several tens of amperes, but becomes a big disadvantage as the capacity increases.

  On the other hand, in order to take advantage of each of the switching device using the contact switch and the switching device using the semiconductor switch, a hybrid switching device combining both the contact switch and the semiconductor switch has been proposed. Yes.

  The thing of patent document 1 is the example, and it shows in FIG. When the main contact of the double-throw electromagnetic contactor 6 that is a contact switch is connected to the normal-side AC power supply 1 side and the load 5 is fed from the normal-side AC power supply 1, the double-throw electromagnetic contactor The semiconductor switches 10 and 20 connected in parallel with the main contact on the common AC power supply 1 side of 6 and the main contact of the standby AC power supply 2 are both turned off.

  In this state where power is supplied to the load from the normal-side AC power supply 1, when it is desired to switch the power supply to the load to the power supply from the standby-side AC power supply 2 (plan switching), when a switching command signal is input from the outside, First, the drive coil of the double-throw electromagnetic contactor 6 is excited and the main contact connected to the normal-side AC power supply 1 side starts the opening operation. At the same time, the semiconductor switch 10 on the regular AC power supply 1 side is turned on. After the inherent operating time of the double-throw electromagnetic contactor 6, the main contact is disconnected from the normal-side AC power source 1 and connected to the standby-side AC power source 2 side after a certain time (about 10 msec.).

  In the middle of the time zone when the main contact of this double-throw electromagnetic contactor 6 is not connected to the normal AC power supply 1 side or the standby AC power supply 2 side, the semiconductor switch 10 on the normal AC power supply 1 side is turned on. The semiconductor switch 20 on the standby side AC power supply 2 side is turned on after an extremely short time (for example, 3 μsec.). Thereafter, the main contact of the double-throw electromagnetic contactor 6 is connected to the standby AC power supply 2 side, and for a predetermined time (a time sufficiently longer than the chattering continuation time when the double-throw electromagnetic contactor 6 is connected). Later, the semiconductor switch 20 on the standby AC power supply 2 side is turned off.

  However, in this method, in the case of planned switching at the time of maintenance such as UPS connected as an input AC power source of a switching device, almost complete synchronous uninterruptible switching with an instantaneous interruption time of several μsec is performed. In automatic switching in the event of a power failure such as a power failure of the AC power supply on the regular side, the switching time can be as long as about 20 msec. Because only the double-throw electromagnetic contactor with a long operating time is operated without operating the semiconductor switch. .

  In case of manual plan switching under the condition that both the normal side AC power supply 1 and the standby side AC power supply 2 are in a healthy state and the phases of both power sources are coincident (in the case of manual uninterruptible switching) When a switching command signal is input from the outside, the voltage phase of both AC power supplies is calculated to coincide after the operating time of the double throw electromagnetic contactor 6. When the drive coil is excited and the main contact connected to the working AC power supply 1 side starts the opening operation, the semiconductor switch 10 on the working AC power supply 1 side is turned on. Next, when the main contact of the double-throw type electromagnetic contactor 6 is separated from the service AC power supply 1 side and contacts the standby AC power supply 2 side, the semiconductor switch 10 on the service AC power supply 1 side is turned off. After several μsec., The semiconductor switch 20 on the standby AC power supply 2 side is turned on, and the synchronous uninterruptible switching from the normal AC power supply 1 to the standby AC power supply 2 is performed. The switching phase is random due to factors that cannot be specified, such as the frequency difference and the operating time of the double-throw electromagnetic contactor 6, and there is a possibility that surge will occur and the load side will be adversely affected due to switching at peak load current. .

  Moreover, the thing of patent document 2 is another example of a hybrid system, and is shown in FIG. The contact of the magnetic contactor 3 which is a contact switch is in the on state, the contact of the electromagnetic contactor 4 is in the off state, and the semiconductor switch (for example, a reverse-parallel connection configuration of thyristors) 9 connected to the load 5 is in the off state In addition, the other end of the semiconductor switch 9 is connected to the AC power source 2 via the main contact of the double-throw electromagnetic contactor 15, that is, the load 5 is fed from the AC power source 1 through the electromagnetic contactor contact 3. It shows the state being done. When a power supply abnormality such as a voltage drop occurs in the AC power supply 1 on the normal side, the contact of the electromagnetic contactor 3 is operated to be turned off, and the contact moves in the opening direction, so that sufficient insulation performance between the two power sources can be secured. After detecting the time, the polarity of the current or voltage flowing through the contact of the magnetic contactor 3 is detected, and one of the anti-parallel thyristors constituting the semiconductor switch 9 is turned on so that no cross current flows between the two power sources. Arc. Thereafter, it waits for the current flowing through the contact of the magnetic contactor 3 to become zero, and after a predetermined confirmation time, both of the antiparallel connected thyristors constituting the semiconductor switch 9 are ignited. Further, the contact of the electromagnetic contactor 4 is turned on after a predetermined time has elapsed after the both thyristors are lit.

  However, according to this method of FIG. 14, the AC power supply 1 and the AC power supply 2 have different voltage phases, and a cross current is generated between the AC power supply 1 and the AC power supply 2 in the anti-parallel connection thyristor constituting the semiconductor switch 9. Even if one of the thyristors in the non-flowing direction is ignited, this thyristor cannot be turned on because no voltage is applied in the forward direction, and eventually the contact of the electromagnetic contactor 3 opens and the arc current Both of the thyristors connected in antiparallel for the first time after the confirmation time after the stop of the current flow are fired, and the power supply from the AC power supply 2 is started. The sum of the abnormality detection time, the contact opening time of the magnetic contactor 3, the arc current continuation time of the contact, and the confirmation time is longer than 10 msec.

Japanese Patent No. 3420281 Japanese Patent No. 3676638 JP 2008-48474 A

We have seen the above prior art, but when the power supply side AC power supply malfunctions, switch to the standby side AC power supply at high speed (within 1/4 cycle) to suppress power loss during steady operation as much as possible. There is still a method that can be used regardless of the type of commercial system, private generator, UPS, and that meets the conditions of a high-speed power switching device that does not allow cross current flow between the two power sources in any AC power supply abnormal mode. Absent.
The conditions that the high-speed power supply switching apparatus as described above should have are as follows.
1. Regular power supply switch is a contact switch (low power loss)
2. Never simultaneously turn on the two power feed switches. (Cross current prevention)
3. Therefore, the OFF operation time of the contact switch is extremely short. (High speed switching)
4). AC power supply abnormality detection time is short (high-speed switching)

  The present invention has been made in order to solve the above-mentioned problems, and during steady power feeding, power feeding is performed via a contact switch, so that the generated power loss is reduced as much as possible. It is an object of the present invention to provide an uninterruptible power supply switching device that can be switched reliably and at high speed by disconnecting an abnormal power supply and then starting power supply from a standby power supply.

The invention according to claim 1 is a power supply switching device that switches supply of power from one power supply to the other power supply when power is selectively supplied from two AC power supplies to a load.
A contact type double-throw electromagnetic contactor that is a changeover switch between two AC power sources, the normal AC power supply and standby AC power supply, and a series connection between the common contact of this double-throw electromagnetic contactor and the load And a first semiconductor connected in parallel with the double-throw electromagnetic contactor and the solenoid-type electromagnetic contactor between the normal-side AC power supply and the load. And a second semiconductor switch connected in parallel with the double-throw electromagnetic contactor and the solenoid-type electromagnetic contactor between the standby AC power source and the load, An abnormal voltage detection circuit is provided in a line between the contactor and the solenoid type magnetic contactor, and controls the double throw type magnetic contactor, the solenoid type magnetic contactor, the first semiconductor switch, and the second semiconductor switch. A control circuit, and In the magnetic contactor, the main contact is always on and the time from solenoid excitation to main contact opening is about 3 msec. The control circuit performs a switching operation to the standby side AC power supply by exciting the double throw electromagnetic contactor in response to an external switching signal or a signal from the abnormal voltage detection circuit. At the same time, the solenoid type magnetic contactor is excited to start the opening operation of the main contact, and further, the first semiconductor switch is turned on, and the opening of the main contact of the solenoid type magnetic contactor is about After completion in 3 msec., The first semiconductor switch is turned off, and after a few μsec., The second semiconductor switch is turned on to start power feeding from the standby AC power source. Regular use of contactor After disconnecting from the side AC power supply, confirm that the solenoid contactor has been de-energized and the main contact has returned to the ON state, and that the double-throw electromagnetic contactor has been switched to the standby AC power supply. After that, the uninterruptible power supply switching device is configured to turn off the second semiconductor switch. Of course, this apparatus is configured to operate in the same manner as described above for switching from the standby AC power supply to the regular AC power supply. In the present document, the external switching signal means an external switching signal when both the normal AC power supply and the standby AC power supply are healthy.

  According to a second aspect of the present invention, in the first aspect of the invention, the solenoid-type electromagnetic contactor normally turns on the main contact with the force of a spring, and the actuator is pulled against the force of the spring by excitation of the solenoid. The main contact is turned off, and the solenoid is excited by a non-instantaneous power source switching device that is a direct current excitation method using short-time simultaneous discharge of electric charges charged in the electrolytic capacitor.

  According to a third aspect of the present invention, in the first or second aspect of the invention, the first semiconductor switch and the second semiconductor switch are each an uninterruptible power supply switching device having self-extinguishing characteristics.

The invention according to claim 4 is a power supply switching device for switching power supply from one power supply to the other power supply when power is selectively supplied to the load from two AC power supplies.
A contact type double-throw electromagnetic contactor that is a changeover switch between two AC power sources, the normal AC power supply and standby AC power supply, and a series connection between the common contact of this double-throw electromagnetic contactor and the load And a first semiconductor connected in parallel with the double-throw electromagnetic contactor and the solenoid-type electromagnetic contactor between the normal-side AC power supply and the load. And a second semiconductor switch connected in parallel with the double-throw electromagnetic contactor and the solenoid-type electromagnetic contactor between the standby AC power source and the load, An abnormal voltage detection circuit is provided in a line between the contactor and the solenoid type magnetic contactor, and a third semiconductor switch having a self-extinguishing characteristic is connected in parallel to the solenoid type magnetic contactor. Throwing type electromagnetic contactor, solenoid type electric A control circuit for controlling the contactor, the first semiconductor switch, the second semiconductor switch, and the third semiconductor switch is provided. The solenoid-type electromagnetic contactor has a main contact that is always on, The time until the main contact is opened is about 3 msec., Which is shorter than the time from the excitation of the double-throw electromagnetic contactor to the contact opening of the normal-side AC power supply. Upon receiving a signal from the abnormal voltage detection circuit, the double-throw electromagnetic contactor is excited to start the switching operation to the standby AC power supply, and at the same time, the solenoid-type electromagnetic contactor is excited to open the main contact. At the same time, the third semiconductor switch is turned on, and after the opening of the main contact of the solenoid type magnetic contactor is completed after about 3 msec., The third semiconductor switch is turned off, and after several μsec. The second semiconductor switch is turned on to start power feeding from the standby AC power source, and then the double throw electromagnetic contactor is disconnected from the normal AC power source. After confirming that the main contact was returned to the on state by releasing the excitation and that the double-throw electromagnetic contactor was switched to the standby AC power supply, the second semiconductor switch was turned off. An uninterruptible power supply switching device was used. Of course, this apparatus is configured to operate in the same manner as described above for switching from the standby AC power supply to the regular AC power supply.

  The invention according to claim 5 is a power source switching device that switches power supply from one power source to the other power source when power is selectively supplied from two AC power sources to a load. A common contact of a contact-type double-throw electromagnetic contactor that is a changeover switch for two AC power supply systems of AC power supply and a load are connected to each other, and between the normal-side AC power supply and the double-throw electromagnetic contactor. And a second normally closed solenoid connected in series between the standby AC power source and the double throw electromagnetic contactor. An electromagnetic contactor, and a first semiconductor switch connected in parallel with the first solenoid contactor and the double throw electromagnetic contactor between the working AC power supply and the load, and The second solenoid between the standby AC power source and the load. A second semiconductor switch connected in parallel with the id type electromagnetic contactor and the double throw type electromagnetic contactor, an abnormal voltage detection circuit is provided on a line between the double throw type magnetic contactor and the load, A control circuit for controlling the throwing electromagnetic contactor, the first solenoid electromagnetic contactor, the second solenoid electromagnetic contactor, the first semiconductor switch, and the second semiconductor switch; In the solenoid type magnetic contactor, the main contact is always on, and the time from solenoid excitation to main contact opening is about 3 msec. From the excitation of the double throw electromagnetic contactor to the normal AC power supply The control circuit is shorter than the time until contact opening, and the control circuit excites the double-throw electromagnetic contactor in response to an external switching signal or a signal from the abnormal voltage detection circuit to switch to a standby AC power source. At the same time as starting The solenoid type magnetic contactor is excited to start the opening operation of the main contact, and the first semiconductor switch is turned on. After about 3 msec., The main contact of the first solenoid type magnetic contactor is opened. After the pole is completed, the first semiconductor switch is turned off, and after a few μsec., The second semiconductor switch is turned on to start power feeding from the standby AC power source, and then the double throw electromagnetic contact After the device is disconnected from the normal-side AC power source, the main contact is returned to the on-state by releasing the excitation of the first solenoid-type magnetic contactor, and the double-throw electromagnetic contactor is changed to the standby-side AC power source. After confirming the switching, the uninterruptible power supply switching device is configured to turn off the second semiconductor switch. Of course, this apparatus is configured to operate in the same manner as described above for switching from the standby AC power supply to the regular AC power supply.

  The invention according to claim 6 is the invention according to any one of claims 1, 2, 3, and 5, wherein the control circuit is based on an external switching signal when both the normal-side AC power supply and the standby-side AC power supply are healthy. In switching, after receiving an external switching signal, the excitation of the double throw type magnetic contactor and the solenoid type magnetic contactor and the start of the ON operation to the first semiconductor switch are respectively performed for the normal side AC power supply and the standby side AC power supply. The synchronization of the rising zero crossing point of the voltage waveform between the corresponding predetermined lines (for example, between RS) is detected and performed at the same time, and the off operation of the first semiconductor switch is performed with the normal AC power supply and the standby AC Non-instantaneous power switching device configured to synchronize the falling zero-crossing point of the voltage waveform between each corresponding line of the power supply (for example, between RSs) or detect the zero-crossing point of the load current simultaneously It was.

  According to a seventh aspect of the present invention, in the fourth aspect of the present invention, the control circuit receives an external switching signal in switching by the external switching signal when both the normal side AC power source and the standby side AC power source are healthy. After that, the excitation start of the double throw electromagnetic contactor and the solenoid electromagnetic contactor and the start of the ON operation to the third semiconductor switch are performed between the corresponding predetermined lines of the normal side AC power supply and the standby side AC power supply (for example, The synchronization of the rising zero crossing point of the voltage waveform (between RS) is detected and performed at the same time, and the third semiconductor switch is turned off at a predetermined line corresponding to each of the normal AC power supply and the standby AC power supply. An uninterruptible power supply switching device is configured to detect the zero-crossing point of the falling voltage waveform between the terminals (for example, between RSs) or detect the zero-crossing point of the load current and perform this simultaneously.

In the invention of claim 1, the following remarkable effects can be obtained.
When the solenoid type magnetic contactor is excited by an external switching signal or a switching command signal from the abnormal voltage detection circuit, the contact is opened after about 3 msec. After opening the main contact, the first semiconductor switch that was also turned on by the switching command signal is turned off, and the second semiconductor switch is turned on after several μsec. A high-speed switching of a little over 3 msec. From the switching command signal to the switching can be realized. In this switching operation, the normal AC power supply continues until the first semiconductor switch is turned off, and after the second semiconductor switch is turned on after several μsec. In the case of manual plan switching in a healthy state, it is possible to switch the disconnection time of several microseconds, and by adding the phase synchronization of the two power sources to the switching conditions, almost perfect synchronous uninterruptible switching can be realized. . In addition, in the case of automatic switching in which a power failure or voltage drop occurs in the utility power supply, high-speed switching of over 4 msec. Can be realized even if the detection time by the abnormal voltage detection circuit is 1 msec. Further, if the switching time is defined as a zero period, it can be said that the switching time for automatic switching at a 50% voltage drop, for example, is several μsec. Therefore, the power supply can be switched within 1/4 cycle at commercial frequencies of 50 Hz and 60 Hz, and uninterruptible power supply switching is possible.

Also, when switching, after the circuit from the working AC power supply to the load is securely shut off by the main contact of the solenoid type magnetic contactor and the first semiconductor switch, the power supply path from the standby AC power supply is turned on. Therefore, the cross current between the two AC power sources does not flow. Moreover, since it is the electric power feeding by the contact of a double throw type electromagnetic contactor and a solenoid type electromagnetic contactor at the time of steady periods other than a short switching period, an energization loss is small.
Since the operations at the time of switching are substantially the same for the inventions of claims 4 and 5, the same effect can be obtained.

In the invention of claim 2, in addition to the effect of claim 1, the solenoid-type electromagnetic contactor normally turns on the main contact by the force of the spring, and the actuator is pulled against the force of the spring by the excitation of the solenoid. Thus, the main contact is turned off, which eliminates the need for electric power and is economical.
In addition, the method of exciting the solenoid with an AC power supply cannot specify the phase of the AC power supply when the excitation is turned on, so the excitation voltage varies and the initial attractive force and thus the operating time varies, so high-speed opening is necessary. It is not suitable for various uses. On the other hand, according to the simultaneous discharge method of the electric charge charged in the electrolytic capacitor of the present invention, the variation in operation time as in the case of the AC power source excitation method can be eliminated, and a stable and high-speed operation can always be obtained. With the structure and excitation method of the present invention, a fast opening time within 3 msec. Was obtained.

  In addition, for high-speed operation, it is necessary to pass an excitation current of about 100 amperes in a short time of 10 to 20 msec. In the case of direct AC power excitation, in addition to the rated current as a switch, this excitation current However, according to the electrolytic capacitor discharge method of the present invention, since only a very small current required for charging the electrolytic capacitor is required for a certain period of time, it is not necessary to add the capacity of the AC power supply.

  In the switching operation from the normal-side AC power supply to the standby-side AC power supply in the circuit configurations of claims 1, 4 and 5, in order to shut off the power supply path of the normal-side AC power supply as soon as possible, the normally closed main The main contact is opened by exciting a solenoid type magnetic contactor having a contact. When a load current is flowing, it is necessary not only to open the main contact but also to interrupt the arc current. Therefore, in the present invention, at the same time as the excitation of the solenoid type magnetic contactor, the first semiconductor switch that connects the normal-side AC power supply and the load is turned on, and the main contact of the solenoid type magnetic contactor is opened. By commutating the arc current, the main contact does not need to consider the interruption of the arc current. Therefore, the distance between the contacts when off can be minimized as long as the insulation of the applied voltage can be secured. Since the structure can be obtained, higher speed operation can be realized. On the other hand, for the proposition to cut off the power supply path of the normal AC power supply as soon as possible, it is necessary to turn off the first semiconductor switch in the on state immediately after the main contact of the solenoid type magnetic contactor is turned off. There is. According to the third aspect of the present invention, the requirement can be satisfied easily by making the first semiconductor switch a self-extinguishing semiconductor. Note that not only the first semiconductor switch but also the second semiconductor switch has a self-extinguishing characteristic, so that either of the two systems of AC power supplies can be a normal AC power supply and a standby AC power supply. Switching is possible.

  In addition to the effect of claim 1, the invention of claim 4 does not require the first semiconductor switch and the second semiconductor switch to be self-extinguishing type semiconductors, and has an overcurrent than the self-extinguishing type semiconductor. It is sufficient to use a thyristor that is strong to the third semiconductor switch, and it is only necessary to use a self-extinguishing type semiconductor for the third semiconductor switch, which reduces the cost.

  In addition to the effects of the above claims, each of the inventions of claims 6 and 7 includes a normal-side AC power supply and a standby-side AC power supply in plan switching when both the normal-side AC power supply and the standby-side AC power supply are healthy. Since the switching of the first semiconductor switch or the like is performed at the zero crossing synchronization point of the voltage waveform between each corresponding predetermined line (for example, between RS), voltage surge due to wiring and load inductance at the time of switching is minimized. be able to. In particular, if the switching timing is the zero cross point of the load current, a higher effect can be obtained. In addition, the effect is particularly remarkable in the case of a single-phase power supply, and even in the case of switching to a three-phase power supply, one phase is switched at the zero cross point, and the other two phases are switched at ± 120 degrees, and switching at the peak point is avoided. It is done.

The present invention provides a power supply switching device that switches power supply from one power supply to the other power supply when power is selectively supplied from two AC power supplies to a load.
A contact type double-throw electromagnetic contactor that is a changeover switch between two AC power sources, the normal AC power supply and standby AC power supply, and a series connection between the common contact of this double-throw electromagnetic contactor and the load And a first semiconductor connected in parallel with the double-throw electromagnetic contactor and the solenoid-type electromagnetic contactor between the normal-side AC power supply and the load. And a second semiconductor switch connected in parallel with the double-throw electromagnetic contactor and the solenoid-type electromagnetic contactor between the standby AC power source and the load, An abnormal voltage detection circuit is provided in a line between the contactor and the solenoid type magnetic contactor, and controls the double throw type magnetic contactor, the solenoid type magnetic contactor, the first semiconductor switch, and the second semiconductor switch. A control circuit, and In the magnetic contactor, the main contact is always on and the time from solenoid excitation to main contact opening is about 3 msec. It was shorter than the time until the opening.

  Further, the control circuit receives a signal from an external switching signal in the planned switching when both the normal-side AC power supply and the standby-side AC power supply are healthy, and excites the double-throw electromagnetic contactor to standby the At the same time as the switching operation to the AC power supply is started, the solenoid type magnetic contactor is excited to start the opening operation of the main contact, and the operation start to turn on the first semiconductor switch is also performed. And the synchronization of the rising zero cross point of the voltage waveform between the corresponding predetermined lines of each of the standby AC power supplies is detected and performed simultaneously with this, the opening of the main contact of the solenoid type magnetic contactor is completed, and the dual After the throwing-type electromagnetic contactor leaves the contact point of the normal-side AC power source, the first semiconductor switch is turned off. This operation is performed between the corresponding predetermined lines of the normal-side AC power source and the standby-side AC power source. Voltage Detects the synchronization of the falling zero-cross point or the zero-cross point of the load current at the same time, and several seconds later, the second semiconductor switch is turned on and the load power supply from the standby AC power supply is started. Then, after the double-throw electromagnetic contactor is switched to the standby side AC power supply, the solenoid contactor is de-energized to return the main contact to the on state, and the second semiconductor switch is turned on. It was set as the structure turned off. When a signal is received from the abnormal voltage detection circuit, the zero cross pulse is not detected, but the operation is almost the same as described above.

  As a result, the power supply switching from the normal AC power supply to the standby AC power supply does not affect the load due to the power outage or voltage drop when switching the power supply due to abnormal voltage detection in the event of a power failure or voltage drop Non-instantaneous power switching is possible.

Embodiments of the present invention will be described below with reference to the drawings.
FIG. 1 is a schematic diagram showing the outline of the present invention.
The uninterruptible power supply switching device of the present invention includes a double-throw electromagnetic contactor 6 that is a changeover switch between the normal-side AC power supply 1 and the standby-side AC power supply 2, and the common contact and load 5 of the double-throw electromagnetic contactor 6. In parallel with the series circuit of the double-throw electromagnetic contactor 6 and the solenoid-type electromagnetic contactor 30 between the solenoid-type electromagnetic contactor 30 connected in series between the normal-side AC power supply 1 and the load 5. The semiconductor switch 10 is connected, and the semiconductor switch 20 is connected between the standby AC power supply 2 and the load 5 in parallel with the series circuit of the double-throw electromagnetic contactor 6 and the solenoid electromagnetic contactor 30. .

  In addition, an abnormal voltage detection circuit 42 is provided on the line between the double throw electromagnetic contactor 6 and the solenoid electromagnetic contactor 30, and an external switching signal or a signal from the abnormal voltage detection circuit 42 is received. A control circuit 40 for controlling the double throw electromagnetic contactor 6, the solenoid electromagnetic contactor 30, the semiconductor switch 10, and the semiconductor switch 20 is provided.

  The normally closed solenoid type electromagnetic contactor 30 has a main contact in a closed state when the solenoid is not excited and is in an open state while the solenoid is excited. In order to shorten the opening time of the solenoid-type electromagnetic contactor 30, a high-speed opening characteristic of opening time = about 3 msec.

  FIG. 2 is an explanatory view of a solenoid type electromagnetic contactor 30 used in the uninterruptible power supply switching device of the present invention. 35 is a solenoid, and 36 is an actuator that is attracted against the spring force described later by solenoid excitation. , 37 is a movable contact that works in conjunction with the actuator 36, 38 is a fixed contact, and 39 is a spring that presses the movable contact 37 against the fixed contact 38. The solenoid-type electromagnetic contactor 30 is an always-on type electromagnetic contactor, and normally, the movable contact 37 is pressed against the fixed contact 38 by the spring 39 to ensure a predetermined energization current characteristic.

In order to make the contact opening time when the solenoid 36 is excited as fast as possible, the distance between the two sets of opening contacts can sufficiently secure the insulation between the contacts so that the force attracting the actuator by the solenoid becomes stronger. Within the range, the stroke Ls of the movable contact is set to the minimum distance.
In the switching operation of the switching device according to the present invention, the main contact of the solenoid type magnetic contactor is in the on state because the semiconductor switch is connected in parallel during both the opening operation and the on operation, so that the arc current interruption is considered. The fact that it is not necessary and that this main contact is off only for a very short time of several tens of milliseconds during the switching operation period and that it is in the on state in the other steady state is an element that can shorten the distance between the open contact points. It has become.

  In addition, the solenoid excitation uses a DC excitation method that uses a simultaneous simultaneous discharge of the electric charge charged to the electrolytic capacitor, so that the opening time is much more stable than AC power supply excitation, where the opening time varies greatly depending on the applied phase. Characteristics can be secured. Note that the electrolytic capacitor discharge method is also employed for the instantaneous excitation power source of the double throw electromagnetic contactor 6 as a changeover switch to ensure the stability of the operation time. In addition, according to this electrolytic capacitor discharge method, it is not necessary to estimate the instantaneous excitation current of several tens of amperes (A) to nearly 100 amperes (A) in the power source capacity separately from the load current as in the case of the AC excitation method. There is also a merit.

FIG. 3 is a known example of the abnormal voltage detection circuit 42 of the three-phase AC power supply.
A ripple voltage waveform obtained by insulating and stepping down a three-phase AC power source with a transformer 42a and full-wave rectified by a rectifier circuit 42b is compared with a DC reference voltage by a comparator 42c, and the full-wave rectified ripple voltage waveform is a DC reference voltage. It is a circuit that determines that a power failure or voltage drop abnormality has occurred in the three-phase AC power supply when the voltage drops further. According to this detection method, since a smoothing circuit is not required and a time delay element such as an electrolytic capacitor is not used, extremely fast detection can be performed, and the actual detection time is 0.5 msec. Or less.

FIGS. 4A to 4E are diagrams for explaining the operation of the apparatus of the present invention.
First, the case of manual plan switching will be described. FIG. 1A shows a state in which power is supplied to the load 5 from the normal-side AC power source 1 through the double-throw electromagnetic contactor 6 and the solenoid electromagnetic contactor 30. When there is an external command for switching in the control circuit 40, the double throw electromagnetic contactor 6 is excited to start the switching operation to the standby AC power source. At the same time, the solenoid type magnetic contactor 30 is excited to start the opening operation of the main contact. Further, the first semiconductor switch is turned on. Then, as shown in (b), first, the opening of the main contact of the solenoid type magnetic contactor 30 is completed after about 3 msec. From the excitation. At that time, the arc current when the main contact of the solenoid type magnetic contactor 30 is opened forms a path in parallel with the power supply path of the main contact of the solenoid type magnetic contactor 30, and the first semiconductor that is already in the ON state. Since it is commutated to the switch 10, no arc is generated, and the electrode can be opened smoothly.

  The state at this time remains as shown in (b), and the double-throw electromagnetic contactor 6 has not yet moved away from the normal-side AC power supply 1, but the main contact of the solenoid electromagnetic contactor 30 is off, so the load 5 The path at the contact point between the two systems of AC power supplies is in a cut-off state. Thereafter, even if the double-throw electromagnetic contactor 6 is switched to the standby AC power supply 2 side, the contact path is kept off until the solenoid-type electromagnetic contactor 30 is de-energized and the main contact is turned on again. The

  At this time, the load 5 is supplied with power from the normal-side AC power supply 1 via the first semiconductor switch 10, but here, the first semiconductor switch 10 is turned off, and after several μsec. When the switch 20 is turned on, the power supply from the normal side late dragon power source 1 is switched to the power supply from the standby side AC power source 2. Since the switching between the semiconductor switches 10 and 20 can be performed at any time as long as the main contact of the solenoid type magnetic contactor 30 is off, it may be after the opening of the main contact of the solenoid type magnetic contactor 30 is confirmed. In the case of planned switching when the two systems of AC power supplies are healthy, the voltage synchronization of the two systems or the zero crossing point of the load current can be designated as the switching point. Further, the switching between the semiconductor switches 10 and 20 may be any of the states (B), (C), and (D) that change with time. As shown in FIG. The device 6 is switched to the standby side AC power source, the solenoid type magnetic contactor 30 is de-energized and the main contact is returned to the ON state, and the standby side AC power source 2 supplies power to the load 5 through the contact path. After the start, the second semiconductor switch 20 is turned off. All of the above operations are switching from power supply of the normal-side AC power supply 1 to power supply of the standby-side AC power supply 2, but the same operation is performed when switching from the standby side to the normal-side.

  Further, when an abnormality such as a voltage drop such as a power failure occurs in the normal-side AC power supply 1, the abnormal voltage detection circuit 42 in FIG. 1 detects this, and passes through the control circuit 40, and the double-throw electromagnetic contactor 6 and The exciting coil of the solenoid type magnetic contactor 30 is excited, and the first semiconductor switch 10 is turned on. After that, the main contact of the solenoid type electromagnetic contactor 30 is completely opened, and the first semiconductor switch alone is in a power supply state to the load 5, but a power failure or voltage drop occurs in the normal-side AC power supply. Therefore, since it is necessary to switch to the power supply by the healthy standby AC power source 2 as soon as possible, the first semiconductor switch 10 is turned off immediately after the main contact of the solenoid type electromagnetic contactor 30 is completely opened, and several μsec. Later, the second semiconductor switch 20 is turned on to switch from standby AC power supply 2 to power supply via the second semiconductor switch 20. Thereafter, as in the case of planned switching, the double throw electromagnetic contactor 6 is switched to the standby AC power source 2 as shown in FIG. The second semiconductor switch 20 is turned off after the contact is returned to the on state and power supply from the standby AC power supply 2 to the load 5 in the contacted path is started.

  FIG. 5 is a time chart of each part of manual switching from the demand-side AC power supply 1 to the standby-side AC power supply 2 when both the normal-side AC power supply 1 and the standby-side AC power supply 2 are healthy. In the switching by the external command signal, after receiving the external switching signal, the excitation start of the double throw electromagnetic contactor 6 and the solenoid electromagnetic contactor 30 and the on operation start of the first semiconductor switch 10 are started. 1 and the synchronization of the rising zero crossing point of the voltage waveform between the corresponding predetermined lines of each of the standby AC power supply 2 (for example, between RSs) is detected and performed at the same time, and the first semiconductor switch 10 is turned off. The operation of the zero-crossing point of the falling of the voltage waveform between the corresponding predetermined lines (for example, between RSs) of each of the normal-side AC power supply 1 and the standby-side AC power supply 2 immediately after the main contact opening of the solenoid type magnetic contactor 30 is performed. Detect synchronization and do it at the same time. In this figure, after the semiconductor switch 10 on the regular AC power supply 1 side is turned off, the time until the semiconductor switch 20 on the standby AC power supply 2 side is turned on is several μsec.

The switching at these zero cross points is made possible because the solenoid type electromagnetic contactor is employed in the present invention.
From the zero crossing point of the voltage waveform of the AC power supply to the next zero crossing point is 10 msec. At a commercial frequency of 50 Hz and 8.3 msec. At 60 Hz. As described above, when the solenoid type magnetic contactor 30 receives an external switching signal or a signal from the abnormal voltage detection circuit, it opens within about 3 msec., But it takes 20 to 30 msec. For the contact to turn on again. . Accordingly, during this time, the lines of the double throw electromagnetic contactor 6 and the solenoid electromagnetic contactor 30 are turned off, and the zero cross point of the voltage waveform of the AC power supply comes twice during this time. The semiconductor switch 10 can be switched off. On the other hand, in the double throw type magnetic contactor 6, it takes about 10 msec. To excite and open the contact of the working AC power source 1, and it takes less than 10 msec. Therefore, before the first semiconductor switch 10 is switched off at the next zero crossing point, the double throw electromagnetic contactor 6 is turned on at the switching destination contact, and the first semiconductor switch is between the two zero crossing points. 10 cannot be switched on and the first semiconductor switch 10 cannot be switched off. In this way, the switching can be performed at the two zero cross points of the AC power source by utilizing the open state of the main contact of the solenoid type magnetic contactor 30.

  FIG. 6 is a time chart of each part of automatic switching from the normal AC power supply 1 to the standby AC power supply 2 when an abnormal voltage is detected. In this case, since the normal-side AC power supply 1 is abnormal such as a power failure or a voltage drop, there is no room for waiting for conditions such as synchronization. Therefore, the double-throw electromagnetic contactor 6 and the solenoid electromagnetic contactor 30 are detected by detecting abnormal voltage pressure. The exciting coil is excited and the first semiconductor switch 10 is turned on. Thereafter, the first semiconductor switch 10 is turned off immediately after the main contact of the solenoid-type electromagnetic contactor 30 is completely opened within 3 msec., And the second semiconductor switch 20 is turned on after several μsec. The power supply 2 is switched to power supply via the second semiconductor switch 20. The time from the occurrence of abnormality of the normal-side AC power supply 1 to the healthy power supply via the second semiconductor switch 20 from the standby AC power supply 2 is less than 4 msec.

  FIG. 7 shows a second embodiment of the present invention, in which a common contact and a load of a contact type double-throw electromagnetic contactor 6 that is a changeover switch of two AC power sources of a normal AC power source 1 and a standby AC power source 2 are shown. 5 is provided, and a first normally closed solenoid electromagnetic contactor 31 connected in series between the normal-side AC power supply 1 and the double throw electromagnetic contactor 6 is provided, and the standby A second normally closed solenoid type electromagnetic contactor 32 connected in series between the side AC power source 2 and the double-throw electromagnetic contactor 6, and between the normal side AC power source 1 and the load 5, A first semiconductor switch 10 connected in parallel with the first solenoid type electromagnetic contactor 31 and the double throw type electromagnetic contactor 6 is provided, and between the standby AC power supply 2 and the load 5, the first semiconductor switch 10 is provided. The second solenoid type magnetic contactor 32 and the second throw type magnetic contactor 6 connected in parallel A conductor switch 20 is provided, an abnormal voltage detection circuit (not shown) is provided on the line between the double throw electromagnetic contactor 6 and the load 5, and the double throw electromagnetic contactor 6 and the first solenoid electromagnetic contact are provided. A control circuit (not shown) for controlling the device 31, the second solenoid type electromagnetic contactor 32, the first semiconductor switch 10 and the second semiconductor switch 20 is provided.

  In the first and second solenoid type electromagnetic contactors 31 and 32, the main contact is always on, and the time from solenoid excitation to main contact opening is about 3 msec. It is assumed that the time from the excitation of the device 6 to the contact opening of the working AC power supply 1 is shorter, and the control circuit receives the external switching signal or the signal from the abnormal voltage detection circuit and receives the signal from the double-throw electromagnetic contactor 6. At the same time as the switching operation to the standby side AC power supply is started, the first solenoid type electromagnetic contactor 31 is excited to start the opening operation of the main contact, and the first semiconductor switch 10 The first semiconductor switch 10 is turned off after the opening of the main contact of the first solenoid-type electromagnetic contactor 31 is completed, and the second semiconductor switch 20 is turned on after several μsec. The standby AC power After the load feeding from the power source 2 is started and then the double-throw electromagnetic contactor 6 is disconnected from the normal-side AC power supply 1, the main contact is released by releasing the excitation of the first solenoid-type electromagnetic contactor 31. The second semiconductor switch 20 is turned off after confirming that it has returned to the ON state and that the double throw electromagnetic contactor 6 has been switched to the standby AC power source 2. In the case of switching from the standby AC power supply 2 to the normal AC power supply 1 in a state where power is supplied to the load 5, in the above operation, the second solenoid electromagnetic contactor 32 is excited to open the main contact. Play the pole.

  FIG. 8 shows a third embodiment of the present invention. The third embodiment has substantially the same configuration as the first embodiment, and a third semiconductor switch 50 is connected in parallel to the solenoid-type electromagnetic contactor 30. The third semiconductor switch 50 is of a self-extinguishing type. The first semiconductor switch 7 and the second semiconductor switch 8 are thyristors that are not self-extinguishing semiconductors. As a result, it is resistant to overcurrent and can reduce costs.

  In this case, upon receiving an external switching signal or a signal from the abnormal voltage detection circuit, the double throw electromagnetic contactor 6 is excited to start the switching operation to the standby AC power supply 2 and at the same time the solenoid electromagnetic contactor. 30 to start the opening operation of the main contact and simultaneously turn on the third semiconductor switch 50, and the third semiconductor immediately after the opening of the main contact of the solenoid type magnetic contactor 30 is completed. The switch 50 is turned off and the second semiconductor switch 8 is turned on after a few μsec. To start the load power supply from the standby side AC power source 2, and then the double throw electromagnetic contactor 6 is used on the normal side AC power source After being disconnected from 1, the excitation of the solenoid type magnetic contactor 30 is released and the main contact is returned to the ON state, and the double throw type electromagnetic contactor 6 is switched to the standby AC power supply 2 Confirmation Later, a structure for turning off the second semiconductor switch 8. In the case of switching from the standby AC power supply 2 to the normal AC power supply 1 in a state where power is supplied to the load 5, in the above operation, the third semiconductor switch 50 is turned off and the first semiconductor switch is turned on after several μsec. The semiconductor switch 7 is turned on to start load power supply from the standby AC power supply 2.

  Next, FIG. 9 shows an application example of the present invention, in which a double-throw electromagnetic contactor 6 that is a changeover switch between the normal-side AC power supply 1 and the standby-side AC power supply 2 and a common contact of the double-throw electromagnetic contactor 6. The solenoid type magnetic contactor 30 connected in series between the power supply 5 and the load 5 is provided, and the third semiconductor switch 50 is connected in parallel to the solenoid type magnetic contactor 30 so that the normal side AC power supply 1 and the standby side AC power supply are connected. A double-throw electromagnetic contactor 15, which is a changeover switch 2, is provided in parallel with the double-throw electromagnetic contactor 6 and the solenoid-type electromagnetic contactor 30, and between the double-throw electromagnetic contactor 15 and the load 5. A fourth semiconductor switch 9 is provided in series. The double-throw electromagnetic contactor 6 is always the contact of the normal-side AC power supply 1 and the double-throw electromagnetic contactor 15 is the contact of the standby-side AC power supply 2. It is connected to the. As a result, the fourth semiconductor switch 9 is integrated into one circuit to reduce the cost.

It is a schematic block diagram of the apparatus of Example 1 of this invention. It is a structure side view of the solenoid type magnetic contactor used for the apparatus of Example 1 of this invention. (A) The figure shows a state in which the main contact is closed, and (b) the figure shows a state in which the main contact is open. It is a block diagram of the abnormal voltage detection circuit of the three-phase alternating current power supply used for the apparatus of Example 1 of this invention. (A) FIGS. (E) to (e) are schematic operation explanatory views of an apparatus according to an embodiment of the present invention. It is a time chart figure of manual switching from AC power supply 1 of Example 1 of the present invention to AC power supply 2. FIG. It is a time chart figure of automatic switching from AC power supply 1 of Example 1 of the present invention to AC power supply 2. FIG. It is a schematic block diagram of the apparatus of Example 2 of this invention. It is a schematic block diagram of the apparatus of Example 3 of this invention. It is a schematic block diagram of the apparatus of the application example of this invention. It is a schematic block diagram of the conventional AC power supply switching device. It is a schematic block diagram of other conventional AC power supply switching devices. It is a schematic block diagram of the further another alternating current power supply switching apparatus. It is a schematic block diagram of the alternating current power supply switching device of patent document 1. It is a schematic block diagram of the alternating current power supply switching device of patent document 2.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Normal side AC power supply 2 Standby side AC power supply 3 Reed switch 4 Reed switch 5 Load 6 Double throw electromagnetic contactor 7 Change switch 8 Change switch 9 Semiconductor switch 10 Semiconductor switch 15 Double throw electromagnetic contactor 20 Semiconductor switch 30 Solenoid electromagnetic contactor 31 Solenoid electromagnetic contactor 32 Solenoid electromagnetic contactor 35 Solenoid 36 Actuator 37 Movable contact 38 Fixed contact 39 Spring 40 Control circuit 42 Abnormal voltage detection circuit 42a Transformer 42b Rectifier circuit 42c Comparator

Claims (7)

In a power supply switching device that switches power supply from one power supply to the other power supply when selectively supplying power to a load from two AC power supplies,
A contact type double-throw electromagnetic contactor that is a changeover switch between two AC power sources, the normal AC power supply and standby AC power supply, and a series connection between the common contact of this double-throw electromagnetic contactor and the load Provided with a normally closed solenoid type magnetic contactor,
A first semiconductor switch connected in parallel with the double-throw electromagnetic contactor and the solenoid electromagnetic contactor is provided between the normal-side AC power supply and the load,
In addition, a second semiconductor switch connected in parallel with the double-throw electromagnetic contactor and the solenoid electromagnetic contactor is provided between the standby AC power supply and the load.
An abnormal voltage detection circuit is provided on the line between the double throw electromagnetic contactor and the solenoid electromagnetic contactor,
A control circuit for controlling the double throw electromagnetic contactor, the solenoid electromagnetic contactor, the first semiconductor switch, and the second semiconductor switch;
In the solenoid type magnetic contactor, the main contact is always on, and the time from solenoid excitation to main contact opening is shorter than the time from excitation of the double throw electromagnetic contactor to main contact opening. ,
The control circuit receives an external switching signal or a signal from the abnormal voltage detection circuit to excite the double-throw electromagnetic contactor to start a switching operation to a standby AC power source and at the same time, the solenoid electromagnetic contactor To start the opening operation of the main contact, turn on the first semiconductor switch, and turn off the first semiconductor switch after the opening of the main contact of the solenoid type magnetic contactor is completed. Immediately after that, the second semiconductor switch is turned on to start power feeding from the standby AC power source, and after the double-throw electromagnetic contactor is disconnected from the normal AC power source, the solenoid type After confirming that the magnetic contactor has been de-energized and that the main contact has returned to the ON state, and that the double-throw electromagnetic contactor has been switched to the standby AC power supply, turn off the second semiconductor switch Characterized by being a configuration in which, uninterruptible power switching device.   The solenoid-type electromagnetic contactor is configured such that the main contact is normally turned on by the force of a spring, and the main contact is turned off by the actuator being pulled against the spring force by excitation of the solenoid. 2. The uninterruptible power supply switching device according to claim 1, wherein a direct current excitation method is used in which electric charges charged in the electrolytic capacitor are simultaneously discharged for a short time.   3. The uninterruptible power supply switching device according to claim 1, wherein each of the first semiconductor switch and the second semiconductor switch has a self-extinguishing characteristic. In a power supply switching device that switches power supply from one power supply to the other power supply when selectively supplying power to a load from two AC power supplies,
A contact type double-throw electromagnetic contactor that is a changeover switch between two AC power sources, the normal AC power supply and standby AC power supply, and a series connection between the common contact of this double-throw electromagnetic contactor and the load Provided with a normally closed solenoid type magnetic contactor,
A first semiconductor switch connected in parallel with the double-throw electromagnetic contactor and the solenoid electromagnetic contactor is provided between the normal-side AC power supply and the load,
In addition, a second semiconductor switch connected in parallel with the double-throw electromagnetic contactor and the solenoid electromagnetic contactor is provided between the standby AC power supply and the load.
An abnormal voltage detection circuit is provided on the line between the double throw electromagnetic contactor and the solenoid electromagnetic contactor,
A third semiconductor switch having a self-extinguishing characteristic is connected in parallel to the solenoid type magnetic contactor,
A control circuit for controlling the double throw electromagnetic contactor, the solenoid electromagnetic contactor, the first semiconductor switch, the second semiconductor switch, and the third semiconductor switch;
In the solenoid type magnetic contactor, the main contact is always on, and the time from solenoid excitation to main contact opening is shorter than the time from excitation of the double throw electromagnetic contactor to main contact opening. ,
The control circuit receives an external switching signal or a signal from the abnormal voltage detection circuit to excite the double-throw electromagnetic contactor to start a switching operation to a standby AC power source and at the same time, the solenoid electromagnetic contactor And the third semiconductor switch is turned on at the same time, and after the opening of the main contact of the solenoid type magnetic contactor is completed, the third semiconductor switch is turned on. Immediately after that, the second semiconductor switch is turned on to start power feeding from the standby AC power source, and then the double throw electromagnetic contactor is disconnected from the normal AC power source, and then the solenoid After confirming that the main contact has returned to the ON state by releasing the excitation of the electromagnetic contactor, and that the double-throw electromagnetic contactor has been switched to the standby AC power source, the second semiconductor switch Characterized in that the arrangement for turning off the uninterruptible power switching device. In a power supply switching device that switches power supply from one power supply to the other power supply when selectively supplying power to a load from two AC power supplies,
Connect the common contact of the contact type double-throw electromagnetic contactor that is a changeover switch of two AC power sources, the normal AC power source and the standby AC power source, and the load.
A first normally closed solenoid electromagnetic contactor connected in series between the normal-side AC power supply and the double-throw electromagnetic contactor; and the standby-side AC power supply and the double-throw electromagnetic contactor; A second normally closed solenoid type electromagnetic contactor connected in series between
A first semiconductor switch connected in parallel with the first solenoid-type electromagnetic contactor and the double-throw-type electromagnetic contactor is provided between the normal-side AC power supply and the load,
In addition, a second semiconductor switch connected in parallel with the second solenoid electromagnetic contactor and the double throw electromagnetic contactor is provided between the standby AC power supply and the load,
An abnormal voltage detection circuit is provided on the line between the double-throw electromagnetic contactor and the load,
A control circuit for controlling the double throw electromagnetic contactor, the first solenoid contactor, the second solenoid contactor, the first semiconductor switch, and the second semiconductor switch;
In the first and second solenoid type electromagnetic contactors, the main contact is normally on, and the time from solenoid excitation to main contact opening is from the double throw electromagnetic contactor excitation to main contact opening. Shorter than
The control circuit receives an external switching signal or a signal from the abnormal voltage detection circuit and excites the double throw electromagnetic contactor to start a switching operation to a standby AC power source, and at the same time, the first solenoid type The magnetic contactor is excited to start the opening operation of the main contact, the first semiconductor switch is turned on, and the opening of the main contact of the first solenoid type magnetic contactor is completed. The first semiconductor switch is turned off, and immediately after that, the second semiconductor switch is turned on to start load power supply from the standby side AC power source. Thereafter, the double throw electromagnetic contactor is disconnected from the normal side AC power source. After confirming that the main contact has returned to the on state by releasing the excitation of the first solenoid type magnetic contactor and that the double throw type magnetic contactor has been switched to the standby side AC power source, Said second half Characterized by being configured to turn off the body switch, uninterruptible power switching device.   After receiving the external switching signal, the control circuit starts the excitation of the double-throw type electromagnetic contactor and the solenoid type electromagnetic contactor and starts the ON operation to the first semiconductor switch. The synchronization of the rising zero-crossing point of the voltage waveform between each corresponding predetermined line is detected and simultaneously performed, and the first semiconductor switch is turned off to open the main contact of the solenoid type magnetic contactor It is characterized in that it is configured to synchronize the falling zero cross point of the voltage waveform between the corresponding lines of the normal AC power supply and the standby AC power supply immediately after that, or to detect the zero cross point of the load current and perform it simultaneously with this. The uninterruptible power supply switching device according to any one of claims 1, 2, 3, and 5.   After receiving the external switching signal, the control circuit starts the excitation of the double-throw type electromagnetic contactor and the solenoid type electromagnetic contactor and starts the ON operation to the third semiconductor switch. The synchronization of the rising zero cross point of the voltage waveform between each corresponding predetermined line is detected and performed simultaneously with this, and the third semiconductor switch is turned off to open the main contact of the solenoid type magnetic contactor It is characterized in that it is configured to synchronize the falling zero cross point of the voltage waveform between the corresponding lines of the normal AC power supply and the standby AC power supply immediately after that, or to detect the zero cross point of the load current and perform it simultaneously with this. The uninterruptible power supply switching device according to claim 4.

Images