JP5109888B2 - Uninterruptible power system - Google Patents

Description

  The present invention relates to an uninterruptible power supply apparatus including a bypass route that directly supplies an AC power output such as a commercial power supply.

  2. Description of the Related Art Conventionally, uninterruptible power supply devices aiming at short-time blackout compensation have been used in various systems and devices as power supply means having high supply reliability. When the commercial power supply is normal, the continuous power supply type uninterruptible power supply system converts AC power from the commercial power supply into DC power, smoothes the obtained DC power, and further converts it to AC power to stabilize it. Since power is supplied to the load, the output voltage is always constant regardless of voltage fluctuations of the input power supply, and frequency disturbance does not occur. Moreover, when a commercial power supply causes a power failure or the like, the uninterruptible power supply device converts DC power from a storage battery or a capacitor into AC power and supplies it to a load.

  Moreover, the uninterruptible power supply device of a constant inverter power supply system has a bypass route that directly supplies power from an AC power supply in preparation for an inverter failure. FIG. 6 is a block diagram showing a configuration of a conventional uninterruptible power supply. As shown in FIG. 6, the uninterruptible power supply device includes an AC power source 1, an AC / DC converter 2, a capacitor 3, a DC / AC inverter 4, a switching relay unit 5, and a control circuit 6. And has a bypass route (side path) for supplying power directly from the AC power source 1 to the load without going through the DC / AC inverter 4.

  The AC / DC converter 2 converts AC power output from the AC power source 1 into DC power. The capacitor 3 smoothes the DC power converted by the AC / DC converter 2 and plays a role as a storage battery. The DC / AC inverter 4 converts the DC power converted by the AC / DC converter 2 and smoothed by the capacitor 3 into AC power again.

  The switching relay unit 5 includes a relay coil 5a and a switching relay 5b, and selects one from the output of the AC power supply 1 and the output of the DC / AC inverter 4 and outputs it to a load (not shown). Specifically, the relay coil 5a is connected to the control circuit 6, and when the current flows, the switching relay 5b is switched to the a side (DC / AC inverter 4 side), and the current is not flowing. The switching relay 5b is switched to the b side (AC power source 1 side). Further, as described above, the switching relay 5b switches the contact point so that either the a side (DC / AC inverter 4 side) or the b side (AC power supply 1 side) is connected to the load. As shown in FIG. 6, the output to the load by the switching relay 5b is an AC voltage of 100V AC regardless of whether the a side is selected or the b side is selected, but when the a side is selected, the DC / AC The inverter 4 compensates the constant voltage / constant frequency output regardless of the state of the AC power supply 1.

  The control circuit 6 controls the voltage / frequency of power supplied to the load by controlling the AC / DC converter 2, the DC / AC inverter 4, and the relay coil 5 a, and also outputs the AC power supply 1 and the DC / AC inverter 4. Select one of the outputs to switch the output to the load.

  Next, the operation of the conventional uninterruptible power supply will be described. Since the conventional uninterruptible power supply device shown in FIG. 6 is an inverter power supply system at all times, the power output from the DC / AC inverter 4 is normally supplied to the load. Therefore, the control circuit 6 controls the switching relay 5b to the a side by flowing a current through the relay coil 5a. Further, the control circuit 6 controls the AC / DC converter 2 and the DC / AC inverter 4 so as to supply desired constant voltage / constant frequency power to the load.

  The AC power output from the AC power source 1 is converted into DC power by the AC / DC converter 2, smoothed by the capacitor 3, and input to the DC / AC inverter 4. The DC / AC inverter 4 converts the input DC power into AC power again and outputs it to a load (not shown) via the switching relay unit 5.

  On the other hand, the control circuit 6 continues to supply power to the load when the DC / AC inverter 4 fails, when the power required in overload exceeds the supply capacity of the DC / AC inverter 4 or For example, when inspection / maintenance work is performed with the relay relay 5b kept on, the current to the relay coil 5a is stopped and the switching relay 5b is switched to the b side. As a result, the AC power supply 1 directly supplies power to the load via the side path and the switching relay unit 5.

  As described above, according to the conventional uninterruptible power supply shown in FIG. 6, the DC / AC inverter 4 can stably supply constant voltage / constant frequency power to the load regardless of the state of the AC power supply 1. In addition, by providing the switching relay unit 5 capable of selecting the power supply path, even when the DC / AC inverter 4 is out of order, the power from the AC power source 1 can be directly supplied to the load using the bypass route. it can.

  Here, the uninterruptible power supply shown in FIG. 6 has a problem that the switching relay unit 5 cannot be controlled when the control circuit 6 fails. When the control circuit 6 breaks down, the control circuit 6 cannot control the DC / AC inverter 4 and the output of the DC / AC inverter 4 stops. Therefore, the switching relay 5b is moved to the b side (bypass route side). Ideally, direct power supply by the AC power source 1 is switched to the load. However, when a current continues to flow through the relay coil 5a due to a failure of the control circuit 6, the control circuit 6 cannot switch the switching relay 5b to the b side, and stops power supply to the load.

  In order to solve this problem, it is conceivable to change the configuration of the uninterruptible power supply as shown in the block diagram of FIG. The uninterruptible power supply shown in FIG. 7 is different from the uninterruptible power supply shown in FIG. 6 in that the switching relay unit 5 is connected to the output side of the DC / AC inverter 4 instead of the relay coil 5a. It is a point with.

  The relay coil 5 c performs switching control of the relay 5 b according to the output of the DC / AC inverter 4. Specifically, when the DC / AC inverter 4 is operating, a current flows through the relay coil 5c. Therefore, the relay coil 5c connects the switching relay 5b to the a side (DC / AC inverter) as shown in FIG. 4 side). As a result, the power output from the AC power supply 1 is stabilized via the AC / DC converter 2, the capacitor 3, and the DC / AC converter 4, and then output to the load via the switching relay unit 5.

  On the other hand, since the current does not flow through the relay coil 5c when the DC / AC inverter 4 is not operating, the relay coil 5c connects the switching relay 5b to the b side (AC power source 1 side) as shown in FIG. Switch control to. As a result, the electric power output from the AC power supply 1 is directly output to the load via the bypass route (side path) and the switching relay unit 5.

  Further, the control circuit 6 can control the relay coil 5 c regardless of whether the output of the DC / AC inverter 4 is present. Therefore, even when the DC / AC inverter 4 is in operation, the control circuit 6 controls the relay coil 5c to forcibly switch the switching relay 5b to the b side (the AC power source 1 side), for example, during an overload. be able to.

  7 and 8, when the control circuit 6 breaks down and the output of the DC / AC inverter 4 stops, the switching relay 5b is automatically set to the b side (AC power source 1 side). Since switching control can be performed, power supply to the load can be continued without stopping.

Patent Document 1 describes an uninterruptible power supply circuit including a switch that switches according to the outputs of two uninterruptible power supply apparatuses. According to this uninterruptible power supply circuit, even when the output of one of the two uninterruptible power supply devices is stopped, the load is automatically connected to the uninterruptible power supply device having the output according to the state of the output. Therefore, the power supply to the load can be continued without stopping.
Japanese Utility Model Publication No. 3-86751

  However, in the uninterruptible power supply shown in FIGS. 7 and 8, the switching relay unit 5 always selects either the AC power source 1 side output or the DC / AC inverter 4 side output and outputs it to the load. When the AC inverter 4 stops and no voltage is applied to the relay coil 5c, the AC power supply 1 side is automatically selected, so that the power supply to the load cannot be stopped as necessary. Has a point.

  If a control relay that performs on / off control of the output with respect to the load is provided after the switching relay unit 5 and the control relay 6 can control the control relay, the uninterruptible power supply can be connected to the load. The power supply can be stopped if necessary.

  However, such an uninterruptible power supply cannot control the control relay when the control circuit 6 breaks down, and various problems occur depending on the type of contact of the control relay. For example, if the control relay is an a-contact relay (a relay that closes when the coil is energized), the control relay is turned off when the control circuit 6 fails, and the uninterruptible power supply forcibly supplies power to the load. Will stop.

  Conversely, if the control relay is a b-contact relay (a relay that opens when the coil is energized), the control relay turns on when the control circuit 6 fails, and the uninterruptible power supply supplies power to the load. Forced to start. In this case, the uninterruptible power supply may appear to stop the output when viewed from the user side, but there may be a situation where power is actually supplied to the load. There is a possibility that a problem such as a malfunction of a load due to an unintended output and a safety problem such as an electric shock of a user may be caused.

  The present invention solves the above-described problems of the prior art, and is capable of controlling on / off of power supply to a load and can avoid unintended output switching to the load even in the event of a failure. It is an object to provide an apparatus.

An uninterruptible power supply according to the present invention has an inverter power supply unit that outputs stabilized AC power based on AC power output by an AC power supply, a switching relay, and a relay coil in order to solve the above-described problem . Yes a switching relay unit for selecting and outputting one of the output of the output and the inverter power supply portion of the AC power supply in accordance with the force output by the inverter power source unit, the reset coil for the set coil and the disconnection of the connection And controlling the operation of the inverter power supply unit and controlling the switching of the switching relay unit when the inverter power supply unit outputs the latching relay that controls the supply of the AC power output by the switching relay unit to the load. A control circuit, and further, the control circuit allows the current to flow through the set coil or the reset coil. Controlling the on / off of the switching relay, and the relay coil controls the switching relay to the AC power source side when the control circuit fails and the output of the inverter power supply unit is not applied to the relay coil, The latching relay maintains an on state or an off state immediately before the control circuit fails .

  According to the present invention, it is possible to provide an uninterruptible power supply that can control on / off of power supply to a load and can avoid unintended output switching for the load even in the event of a failure.

  Embodiments of the uninterruptible power supply apparatus of the present invention will be described below in detail with reference to the drawings.

  Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram illustrating the configuration of the uninterruptible power supply according to the first embodiment of the present invention. As shown in FIG. 1, the uninterruptible power supply includes an AC power source 1, an AC / DC converter 2, a capacitor 3, a DC / AC inverter 4, a switching relay unit 5, a control circuit 6, and a control relay. And a bypass route (side path) for supplying power directly from the AC power supply 1 without passing through the DC / AC inverter 4. That is, the difference from the conventional uninterruptible power supply shown in FIGS. 7 and 8 is that the control relay unit 7 is provided.

  The AC / DC converter 2, the capacitor 3, and the DC / AC inverter 4 correspond to the inverter power supply unit of the present invention and output stabilized AC power based on the AC power output from the AC power supply 1.

  The AC / DC converter 2 converts AC power output from the AC power source 1 into DC power. The capacitor 3 smoothes the DC power converted by the AC / DC converter 2 and plays a role as a storage battery. The DC / AC inverter 4 converts the DC power converted by the AC / DC converter 2 and smoothed by the capacitor 3 into AC power again.

  The switching relay unit 5 includes a relay coil 5c and a switching relay 5b, and selects and outputs either the output of the AC power source 1 or the output of the inverter power source unit according to the presence or absence of the output from the inverter power source unit. The relay coil 5 c is connected to the output side of the DC / AC inverter 4 and performs switching control of the switching relay 5 b according to the output of the DC / AC inverter 4. The specific operation of the relay coil 5c is the same as that of the relay coil 5c of the conventional uninterruptible power supply apparatus described with reference to FIGS. Further, the switching relay 5b is a c-contact relay (relay that switches contacts) so that either the a side (DC / AC inverter 4 side) or the b side (AC power supply 1 side) is connected to the load, as in the conventional case. A relay that switches a plurality of contacts in accordance with the energization state of the coil 5c.

  The control relay unit 7 corresponds to the latching relay of the present invention, has a connection set coil 7a and a reset coil 7b, and controls the supply of the AC power output by the switching relay unit 5 to the load. Specifically, since the control relay unit 7 is a latching relay, the control relay unit 7 is turned on when a voltage is applied to the set coil 7a and a predetermined current flows, and the voltage is applied to the reset coil 7b to generate a predetermined current. Turns off when is flowing. In other words, the control relay unit 7 continues to be in the on state unless a voltage is applied to the reset coil 7b after the set coil 7a is energized and turned on.

  The control circuit 6 controls the voltage / frequency of the power supplied to the load by controlling the operation of the inverter power supply unit (AC / DC converter 2 and DC / AC inverter 4). Further, the control circuit 6 can control the switching of the switching relay unit 5 by controlling the relay coil 5c regardless of the output of the inverter power supply unit (DC / AC inverter 4). Thus, one of the AC power supply 1 output and the DC / AC inverter 4 output by the bypass route (side path) is selected to switch the output to the load. That is, the relay coil 5c performs switching control of the switching relay 5b in accordance with the output of the DC / AC inverter 4 as described above in a normal state, but the operation state of the DC / AC inverter 4 is changed as in an overload. Regardless, when the output of the AC power supply 1 via the bypass route (side path) is required, the switching control of the switching relay 5b is performed according to the forced control by the control circuit 6.

  Further, the control circuit 6 controls on / off of the control relay unit 7 (latching relay) by controlling the current flowing through the set coil 7a and the reset coil 7b. Thereby, the ON / OFF timing of the control relay unit 7 is determined by, for example, the user pressing an external switch. In this case, the control circuit 6 controls the on / off of the control relay unit 7 by causing a current to flow through the set coil 7a or the reset coil 7b according to the state of the external switch. Thereby, the control circuit 6 can control ON / OFF of the power supply with respect to a load.

  Next, the operation of the present embodiment configured as described above will be described. First, since the uninterruptible power supply shown in FIG. 1 is a constant inverter power supply system, the power output from the DC / AC inverter 4 is normally supplied to the load. The control circuit 6 controls the AC / DC converter 2 and the DC / AC inverter 4 so as to supply desired constant voltage / constant frequency power to the load.

  FIG. 2 is a diagram illustrating an operation when the DC / AC inverter 4 of the uninterruptible power supply device according to the first embodiment of the present invention is operating normally. In this case, the AC power output from the AC power source 1 is converted into DC power by the AC / DC converter 2, smoothed by the capacitor 3, and input to the DC / AC inverter 4. The DC / AC inverter 4 converts the input DC power into AC power again and outputs it. That is, as shown in FIG. 2, the DC / AC inverter 4 outputs constant voltage / constant frequency power (normal inverter voltage) according to the control of the control circuit 6.

  Since the current flows through the relay coil 5c when the inverter voltage generated by the DC / AC inverter 4 is applied, the relay coil 5c switches the switching relay 5b to the a side (DC / AC inverter 4 side). Further, the control circuit 6 controls the control relay unit 7 to be turned on by passing a current through the set coil 7a.

  As a result, the power output from the AC power supply 1 is stabilized via the AC / DC converter 2, the capacitor 3, and the DC / AC converter 4, and then supplied to the load via the switching relay unit 5 and the control relay unit 7. Is done.

  Note that since the control relay unit 7 is a latching relay, it is not necessary to continue the flow of current once it is turned on by energizing the set coil 7a, and the ON state is maintained until a current flows to the reset coil 7b thereafter. To do.

  In addition, the control circuit 6 turns on the relay coil 5c regardless of whether the output of the DC / AC inverter 4 is present or not when the power required at the time of overload exceeds the supply capacity of the DC / AC inverter 4. Thus, the switching relay 5b can be forcibly switched to the b side. In this case, the AC power supply 1 directly supplies power to the load via the side path, the switching relay unit 5, and the control relay unit 7.

  Next, the case where the uninterruptible power supply is stopped and the power supply to the load is stopped will be described. FIG. 3 is a diagram illustrating an operation when the DC / AC inverter 4 of the uninterruptible power supply according to the first embodiment of the present invention is stopped. In this case, since the inverter coil generated by the DC / AC inverter 4 is not applied to the relay coil 5c and no current flows, the relay coil 5c switches the switching relay 5b to the b side (AC power supply 1 side). To do. For this reason, the AC power output from the AC power source 1 is supplied to the switching relay unit 5 directly via the bypass route (side path) without passing through the inverter power source unit.

  However, when the uninterruptible power supply is stopped, the control circuit 6 controls the control relay unit 7 to be turned off by passing a current through the reset coil 7b. Therefore, the power output from the AC power supply 1 is not supplied to the load.

  Next, the operation when the control circuit 6 fails during normal operation of the uninterruptible power supply (that is, the state of FIG. 2) will be described. FIG. 4 is a diagram illustrating an operation when the control circuit 6 fails during normal operation of the uninterruptible power supply device according to the first embodiment of the present invention. In this case, the DC / AC inverter 4 stops operation because control by the control circuit 6 is lost. Therefore, the inverter voltage by the DC / AC inverter 4 is not applied to the relay coil 5c, and the relay coil 5c switches the switching relay 5b to the b side (AC power source 1 side). As a result, the AC power output from the AC power source 1 is supplied to the switching relay unit 5 via the bypass route (side path) directly without passing through the inverter power source unit.

  On the other hand, the control circuit 6 cannot flow current to the set coil 7a and the set coil 7b after the failure. The control relay unit 7 that has been on-controlled during normal operation maintains the on-state even after the control circuit 6 fails and the current to the set coil 7a is lost. Therefore, the electric power output from the AC power supply 1 is supplied to the load via the bypass route (side path), the switching relay unit 5, and the control relay unit 7. That is, the uninterruptible power supply device of the present invention continuously supplies power without stopping power supply to the load even when the control circuit 6 fails during normal operation. Can be avoided.

  Next, the operation when the control circuit 6 fails while the uninterruptible power supply is stopped (that is, in the state shown in FIG. 3) will be described. FIG. 5 is a diagram illustrating an operation when the control circuit 6 fails while the uninterruptible power supply according to the first embodiment of the present invention is stopped. In this case, the DC / AC inverter 4 remains stopped through before and after the failure of the control circuit 6. Therefore, the relay coil 5c controls the switching relay 5b to be maintained on the b side (AC power source 1 side). The AC power output from the AC power source 1 is supplied to the switching relay unit 5 via the bypass route (side path) directly without passing through the inverter power source unit, as in the case shown in FIG.

  Further, the control circuit 6 cannot flow current to the set coil 7a and the set coil 7b after the failure. The control relay unit 7 that has been off-controlled while the uninterruptible power supply is stopped (that is, the state shown in FIG. 3) maintains the off-state even after the control circuit 6 fails and the current to the reset coil 7b is lost. To do. Therefore, the power output from the AC power supply 1 is not supplied to the load even after the control circuit 6 has failed. That is, the uninterruptible power supply apparatus of the present invention avoids a situation in which the power supply to the load is suddenly restarted unintentionally when the control circuit 6 breaks down while the operation is stopped. Electric shock or the like can be prevented.

  As described above, according to the uninterruptible power supply according to the first embodiment of the present invention, it is possible to control on / off of power supply to the load, and avoid unintended output switching for the load even at the time of failure. be able to.

  That is, since the uninterruptible power supply device of this embodiment includes the control relay unit 7 that is a latching relay, the control circuit 6 controls the control relay unit 7 to control on / off of power supply to the load. In addition, even if the control circuit 6 fails during normal operation or operation stop, the control relay unit 7 continues the output state according to the power supply state immediately before the failure. It is possible to prevent load malfunctions and user electric shocks.

  Further, since the control circuit 6 can control the switching of the switching relay 5b by controlling the relay coil 5c regardless of whether the output of the DC / AC inverter 4 is present or not, the electric power required at the time of overload is DC / When the supply capacity of the AC inverter 4 is exceeded, power can be directly supplied from the AC power supply 1 to the load.

  Furthermore, since the control circuit 6 performs current control (control of the set signal and the reset signal) for the set coil 7a and the reset coil 7b of the control relay unit 7 which is a latching relay, the control circuit 6 stops the control when itself fails. The on / off state of the control relay unit 7 can be maintained.

  The switching relay unit 5 is a c-contact relay that selects one of a route passing through the inverter power supply unit and a bypass route. For example, the contact point for each route may be a contact relay and b contact relay. Conceivable. In that case, the switching relay unit 5 can switch the connection of the route depending on whether or not the both-contact relay is energized. However, the switching relay unit 5 configured with two contact relays may turn off the power supply by turning off both contact relays when one of the contact relays fails. In that respect, the switching relay unit 5 that uses the c-contact relay as in this embodiment has a low possibility that the power supply to the load will stop unintentionally because either one of the contacts is always connected. There are advantages.

  The uninterruptible power supply according to the present invention can be used for an uninterruptible power supply using other AC power such as a commercial power supply or an AC generator.

It is a block diagram which shows the structure of the uninterruptible power supply device of the form of Example 1 of this invention. It is a figure which shows operation | movement in case the DC / AC inverter of the uninterruptible power supply of the form of Example 1 of this invention is operating normally. It is a figure which shows operation | movement in case the DC / AC inverter of the uninterruptible power supply of the form of Example 1 of this invention has stopped. It is a figure which shows operation | movement when a control circuit fails during normal operation of the uninterruptible power supply of the form of Example 1 of this invention. It is a figure which shows operation | movement when a control circuit fails while the uninterruptible power supply of the form of Example 1 of this invention stops. It is a block diagram which shows the structure of the conventional uninterruptible power supply. It is a figure which shows operation | movement of the conventional uninterruptible power supply. It is a figure which shows operation | movement of the conventional uninterruptible power supply.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 AC power source 2 AC / DC converter 3 Capacitor 4 DC / AC inverter 5 Switching relay part 5a Relay coil 5b Switching relay 5c Relay coil 6 Control circuit 7 Control relay part 7a Set coil 7b Reset coil

Claims (2)

An inverter power supply unit that outputs stabilized AC power based on the AC power output by the AC power supply;
It has a switching relay and a relay coil, and a switching relay unit for one selects and outputs the output of the inverter power supply section and the output of the AC power supply in accordance with the force output by the inverter power supply unit,
A latching relay having a set coil for connection and a reset coil for disconnection, and controlling supply to a load of AC power output by the switching relay unit;
A control circuit for controlling the operation of the inverter power supply unit and performing switching control of the switching relay unit at the time of output of the inverter power supply unit;
Furthermore, the control circuit controls the on / off of the latching relay by passing a current through the set coil or the reset coil,
The relay coil switches the switching relay to the AC power source when the control circuit fails and the output of the inverter power supply unit is not applied to the relay coil,
The uninterruptible power supply apparatus , wherein the latching relay maintains an on state or an off state immediately before the control circuit fails . The inverter power supply unit
An AC / DC converter that converts AC power output from the AC power source into DC power;
The uninterruptible power supply apparatus according to claim 1, further comprising a DC / AC inverter that converts DC power output by the AC / DC converter into AC power .

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