TWI492486B - Exchange standby power system - Google Patents

Description

Exchange backup power system

The invention relates to an AC backup power supply system, in particular to a problem that ensures that an AC power source cuts into a power supply at a zero crossing point, and does not cause arcing or carbon loss during switching.

In order to ensure the stability of the power supply, the high-standard power supply system has a so-called redundant design. The so-called redundant power supply system mainly works by two or more power supply modules. When one of the power supply modules fails and cannot be powered normally, Another power module can immediately replace the faulty power module; the aforementioned redundant design is generally for the load, for the input power of the power system, usually only a single AC power input, so once the AC power is abnormal, The power system cannot supply power to the load even if it has a redundant design.

In order to solve the above problem, a power supply device with an AC backup function is emerged. As shown in FIG. 3, the first to third DC power supply modules 71-73 and a switching circuit 70 are included. The output ends of the third DC power supply modules 71-73 are connected to the load in parallel, wherein the input ends of the first and second DC power supply modules 71, 72 are respectively connected to the first and second AC power sources AC1. The AC2 is connected; the switching circuit 70 has first to third relays 701 to 703, and the third relay 703 is in two-to-one form, which has two input ends and one output end, and the two input ends respectively and the first and second relays 701 The 702 is connected, and the output end is connected to the input end of the third DC power supply module 73, and the input ends of the first and second relays 701 and 702 are respectively connected to the first and second AC power sources AC1. AC2 connection.

When the first and second AC power sources AC1 and AC2 are powered normally, they are respectively supplied to the first and second DC power supply modules 71 and 72, wherein the first AC power source AC1 passes through the first and third relays 701 and 703. The power is supplied to the third DC power supply module 73, so the first to third DC power supply modules 71 to 73 are output in parallel.

If the first AC power source AC1 is interrupted, the first relay 701 is turned off, the second relay 702 is turned on and off, and the third relay 703 is switched to be connected to the second relay 702. At this time, the first DC power supply module 71 is connected. The first AC power supply AC1 is interrupted and stops working; the second DC power supply module 72 is maintained to operate due to the normality of the second AC power supply AC2; the third DC power supply module 73 is transmitted through the third and second relays 703 and 702 from the second The AC power source AC2 takes power and operates in parallel with the second DC power supply modules 71, 72.

Although the aforementioned patents specifically emphasize in the specification that the switching action of the switching circuit 70 must be performed when the AC power source is alternated to zero-crossing, to avoid spurs and sparks during switching. In the specific technical means, and using the microprocessor to detect the AC power, it is expected that the microprocessor can accurately control the relay to switch at zero. However, the aforementioned patent uses a relay as a switching element, and the relay is a mechanical switch, which has a problem of a delay of time, even if the microprocessor detects a crossing zero, but actually reacts to the relay to perform a switching action. The AC power has not crossed the zero point. Since the switch is non-zero, the spark is switched and the spark is generated during the switching, so that the problem of carbon deposition loss cannot be effectively solved.

As can be seen from the above, a backup solution for the input AC power supply is provided. There is a need for interoperability. However, when switching AC power, the existing technologies presented in the aforementioned patent law cannot be reliably switched to zero. Therefore, further review is needed and a feasible solution is sought.

SUMMARY OF THE INVENTION It is therefore a primary object of the present invention to provide an AC backup power supply system that ensures that the AC power source is switched at zero and that no arcing occurs during switching, thereby avoiding loss issues.

The technical means for achieving the foregoing purpose is that the communication backup power supply system includes a power supply, a switching module and a monitoring module; wherein: the power supply has an input power circuit; the switching module has a first a switching unit and a second switching unit, wherein the input ends of the first and second switching units are respectively connected to a main AC power source and a backup AC power source; the outputs of the first and second switching units are switchably The monitoring module comprises: a processing unit; a power monitoring unit having an input end and an output end, wherein the input ends are respectively connected with the main and backup AC power sources, and the output ends thereof are connected The processing unit is connected; a first circuit switch is controlled by the processing unit to be turned on and off, and is connected in series to the input power circuit between the switching module and the power supply; and a second circuit switch is an electronic switch, which is subjected to The processing unit controls on and off, and is connected in parallel with the first circuit switch; the aforementioned alternating backup power supply system is normally only used by the main AC power supply. The first switching unit and the first loop switch of the switching module supply power to the power supply; and the processing unit of the monitoring module monitors the status of the main AC power and the backup AC power through the power monitoring unit at any time, when the main AC power is abnormal Or interrupted, the processing unit will disconnect the normally closed first loop switch and the first switching unit of the switching module, and then turn on the second switching unit to switch the switching module to the backup AC power supply. The processing unit will detect whether the standby AC power supply of the preliminary power supply reaches the zero crossing point. When the zero crossing point is reached, the second loop switch is turned on, and the backup AC power source passes the second of the switching module. The switching unit and the second loop switch supply power to the power supply. Since the second loop switch is an electronic switch, the switching can be reliably performed at the zero crossing point; and after the power supply is stabilized, the processing unit is turned on first. Looping the switch and disconnecting the second loop switch; when the main AC power source is restored to the power supply, the closed first loop switch and the second switching unit are first disconnected according to the above manner, and Measure whether the main AC power source reaches the zero crossover point. When the zero crossover point is reached, the second loop switch is turned on. At this time, the backup AC power supply will be powered by the second switching unit and the second loop switch of the switching module. The power supply, after the power supply is stabilized, the first loop switch is turned on by the processing unit, and the second loop switch is turned off; by using the foregoing technology, when there is a need to switch the AC power supply, the AC power supply is ensured at the zero crossing point. Switching, thereby avoiding input glitch and preventing spark and derivatized carbon loss.

The circuit structure of a preferred embodiment of the present invention is first shown in FIG. 1 , and is mainly composed of a power supply 10 , a switching module 20 , and a monitoring module 30 . In this embodiment, the power supply 10 includes a filter circuit 11, a rectifier circuit 12, and a power factor correction circuit (PFC) 13, and further has a direct current pair at the output of the power factor correction circuit 13. a DC conversion circuit (DC/DC) (not shown in the figure); the power supply 10 also forms an input power supply circuit at the input end of the rectifier circuit 12; the switching module 20 has a first switching unit 21 and a first The switching unit 22, the input ends of the first and second switching units 21, 22 are respectively connected to a main AC power source AC1 and a backup AC power source AC2, and the outputs of the first and second switching units 21, 22 are respectively connected. Switchingly connected to the input power circuit of the power supply 10; in the embodiment, the switching module 20 further provides a third switching unit between the first and second switching units 21, 22 and the power supply 10. 23; wherein: the first switching unit 21 is mainly composed of two relays REL1, REL2, the two relays REL1, REL2 respectively have a common end, and are respectively connected with two power lines L, N of a main AC power supply AC1, and two Relay REL1, REL2 There is a normally open contact and a normally closed contact; the second switching unit 22 is mainly composed of two relays REL3, REL4, and the two relays REL3, REL4 respectively have a common end, and respectively with a backup AC power supply AC2 The two power lines L, N are connected, and the two relays REL3, REL4 respectively have a normally open contact and a normally closed contact; the third switching unit 23 is still mainly composed of two linked relays REL5, REL6, two relays REL5 and REL6 respectively have a common terminal, and are simultaneously connected with the input power supply loop of the power supply 10, and the two relays REL5 and REL6 respectively have a normally open contact and a normally closed contact, respectively, and respectively with the first and second Relays REL1~REL4 of switching units 21, 22 The normally open contact and the normally closed contact are connected; thereby, the switching module 20 will select the input power of the power supply 10 connected by the main AC power source AC1 or the backup AC power source AC2 under the control of the monitoring module 20. Loop.

The monitoring module 30 includes a processing unit 31, which can respectively control the switching of each switching unit of the switching module 20, and receive the alternating current signal of the power supply 10. In the embodiment, the processing unit 31 is mainly composed of a first The processor 311 and the second processor 312 are connected to the second processor 312 through an optical coupler 313. The first processor 311 is coupled to the AC signal detecting circuit 310. The output end of the filter circuit 11 of the power supply 10 and the output end of the rectifier circuit 12 are connected to obtain an AC signal; a power supply monitoring unit 32 has an input end and an output end, and the input ends thereof are respectively connected with the main and backup AC power source AC1. The AC2 is connected to the processing unit 31. The power supply monitoring unit 32 includes a first detector 321 and a second detector 322. The first and second detectors 321 are connected to the processing unit 31. The input ends of the 322 are respectively connected to the main AC power source AC1 and the backup AC power source AC2, and the outputs of the first and second detectors 321, 322 are respectively transmitted through an optical coupler 323, 324 and the first processor of the processing unit 31. 3 11 connections.

A first circuit switch 33 is controlled to be opened and closed by the processing unit 31, and is normally closed in series with the input power circuit between the switching module 20 and the power supply 10; in this embodiment, the first circuit switch 33 is composed of a relay REL 7, and is controlled by the first processor 311 of the processing unit 31 to open and close; a second circuit switch 34 is an electronic switch and is connected in series to the switching module 20 and the power supply 10 input power loops, and the first one The loop switch 33 is connected in parallel; the second loop switch 34 is controlled to be turned on and off by the processing unit 31. In this embodiment, the second loop switch 34 is formed by an alternating current controller (TRIAC), and the gate for controlling the switching is connected to the first processor 311 through a driving circuit 340, that is, The on/off of the second loop switch 34 is controlled by the first processor 311 through the drive circuit 340.

In addition to the above modules, the present invention further includes a power module 40 for supplying power to the monitoring module 30. The power module 40 is mainly composed of two power converters 41 and 42 respectively, and the input terminals are respectively connected to the main AC power source. The AC1 and the backup AC power source AC2 are connected, and the output ends thereof are respectively connected to the first and second detectors 321, 322 and connected to the first and second processors 311 and 312 to supply the power required for the operation. In this embodiment, the two power converters 41, 42 are respectively a flyback power converter.

The working principle of the above-mentioned AC backup power supply system is as follows (please refer to FIG. 2): When the main AC power source AC1 and the backup AC power source AC2 are both normal (t0), the first of the power source monitoring unit 32, The second detectors 321 and 322 respectively detect the power signal, and transmit the detection normal signals AC1_OK and AC2_OK (low potential) to the first processor 311 (t1), but the backup AC power source AC2 is temporarily not powered; The relays REL5 and REL6 of the third switching unit 23 are in a normally closed state and are connected to the first switching unit 21, and the relays REL1 and REL2 of the first switching unit 21 are driven by the first processor 311 to be switched and then switched. The unit 23 is connected, and the first loop switch 33 is also driven by the first processor 311 to be closed, and the main AC power source AC1 transmits power to the power supply through the first and third switching units 21, 23 and the first loop switch 33. 10, the boosting capacitor of the power factor correction circuit 13 at this time (figure The charging is started, and the output voltage (PFC_Bulk) starts to increase and is detected by the first processor 311.

When the main AC power source AC1 is interrupted or abnormal (t2), the first detector 321 stops sending the detection normal signal AC1_OK to the first processor 311, and after the first processor 311 confirms for several ms, the closed first loop switch is turned on. 33 is disconnected first, at this time, no energy enters the power supply 10, and no current flows through the first circuit switch 33, so that sparks can be avoided on the first circuit switch 33, thereby solving the problem of generating sparks on the switch. Carbon problem. Since the first loop switch 33 is turned off, the output voltage (PFC_Bulk) of the power factor correction circuit 13 thus continues to drop.

The first processor 311 then cuts the first switching unit 21 away from the third switching unit 23 and connects the second switching unit 22 with the third switching unit 23, whereby the backup AC power source AC2 is in the preliminary power supply state (t4). Since the first and second loop switches 33, 34 are all in the non-on state at this time, no energy flows into the power supply 10, and the first processor 311 will detect whether the backup AC power source AC2 reaches zero by the second detector 322. Crossover point (t5). When the zero crossing point is reached, the first processor 311 then triggers the second loop switch 34 to be turned on by the driving circuit 340, and the third switching unit 23 is then connected to the power supply 10 input power loop through the second loop switch 34. Since the second loop switch 34 is an electronic switch, it is possible to switch at the zero crossing point with certainty; at this time, the power factor correction circuit 13 output voltage (PFC_Bulk) of the power supply 10 starts to rise again. After the power supply is stabilized (in this embodiment, after the second loop switch 34 is turned on for 50 ms), the first processor 311 turns on the first loop switch 33, and turns off the second loop switch 34 (t6), and recovers from the first The loop switch 33 turns on the input power loop of the power supply 10, and is provided by the backup The streaming power source AC2 continuously supplies power to the power supply 10 (t7). During the foregoing operation, when the power supply is stabilized, the input power supply circuit of the power supply 10 is turned on by the first circuit switch 33, that is, the second circuit switch 34 is used as a relay switch; The electronic second loop switch 34 is connected to the power circuit, and the loss thereof is greater than the first loop switch 33 formed by the relay. Therefore, after the power source is stabilized, the input power loop of the power supply 10 is turned on by the first loop switch 33, which can be reduced. Power loss. Moreover, since the turn-on voltage of the second loop switch 34 is very low, when the first loop switch 33 is switched back, it is affected by the clamp of the second loop switch 34, and the voltage of the conduction is small, so that the first loop switch 33 can be effectively avoided. A spark is generated on the primary circuit switch 33 and the carbon deposit problem therefrom is generated.

When the AC power supply of the AC power supply is restored, the AC power supply of the backup AC power supply can be maintained. When the AC power supply AC2 is abnormal or interrupted, the main AC power supply AC1 is powered back according to the above steps. The steps are as follows: AC2 interrupt or abnormality (t8), the second detector 322 stops sending the detection normal signal AC2_OK to the first processor 311, and after the first processor 311 confirms for several ms, the closed first loop switch 33 is first disconnected. In order to block energy from entering the power supply 10, as described above, the first circuit switch 33 is turned off first to avoid sparking when the current passes, thereby preventing carbon deposition on the switch. Since the first loop switch 33 is turned off, the output voltage (PFC_Bulk) of the power factor correction circuit 13 will drop.

Then, the first processor 311 cuts off the second switching unit 22 from the third switching unit 23, and switches the third switching unit 23 to be connected to the first switching unit 21, thereby bringing the main AC power source AC1 into a standby power supply state (t9). ). The first processor 311 will detect the primary AC power source AC1 by the first detector 321 Whether to reach the zero crossing point. When the zero crossing point is reached, the first processor 311 then triggers the second loop switch 34 to be turned on by the driving circuit 340, and the third switching unit 23 is then connected to the power supply 10 input power loop through the second loop switch 34. The power factor correction circuit 13 of the power supply 10 outputs a voltage (PFC_Bulk) and thus starts to rise. After the power supply is stabilized (in this embodiment, after the second loop switch 34 is turned on for 50 ms), the first circuit switch 33 is turned on by the first processor 311, and the second loop switch 34 is turned off (t10), and the recovery is performed. The primary circuit switch 33 turns on the input power supply circuit of the power supply 10, and continuously supplies power to the power supply 10 from the main AC power supply AC1.

As described above, the second loop switch 34 is used as a relay switch to ensure switching at the zero crossing point, and after the power source is stabilized, the power loop is restored by the first loop switch 33 to reduce the power. loss. Moreover, since the turn-on voltage of the second loop switch 34 is low, when the first loop switch 33 is switched back, it is affected by the clamping of the second loop switch 34, and the voltage for turning on is also small, thereby effectively avoiding A spark and its derived carbon deposit problem are generated on the first circuit switch 33.

It can be seen from the above that the AC backup power supply system of the present invention can provide a main AC power supply and a backup AC power supply to alternately supply power to the power supply, and when the main AC power supply and the backup AC power supply are switched, the electronic power supply is electronically The second loop switch of the type is accurately switched at the zero crossing point. When switching, the first loop open relationship formed by the relay is in the off state, so no current flows; on the other hand, after the power source is stabilized, When the primary circuit switch is switched back to the power supply circuit, it is affected by the clamp of the second circuit switch, and its passing voltage is small, so the problem of spark and derivatized carbon loss can be effectively avoided.

10‧‧‧Power supply

11‧‧‧Filter circuit

12‧‧‧Rectifier circuit

13‧‧‧Power Factor Correction Circuit

20‧‧‧Switch Module

21‧‧‧First switching unit

22‧‧‧Second switching unit

23‧‧‧ Third switching unit

30‧‧‧Monitoring module

31‧‧‧Processing unit

310‧‧‧AC signal detection circuit

311‧‧‧First processor

312‧‧‧second processor

313‧‧‧Optocoupler

32‧‧‧Power Monitoring Unit

321‧‧‧First detector

322‧‧‧Second detector

323, 324‧‧‧Optocoupler

33‧‧‧First loop switch

34‧‧‧Second circuit switch

340‧‧‧ drive circuit

40‧‧‧Power Module

41, 42‧‧‧Power Converter

70‧‧‧Switching circuit

701‧‧‧First relay

702‧‧‧Second relay

703‧‧‧third relay

71‧‧‧First DC power supply module

72‧‧‧Second DC power supply module

73‧‧‧ Third DC Power Supply Module

1 is a circuit diagram of a preferred embodiment of the present invention.

2 is a timing diagram of a preferred embodiment of the present invention.

Fig. 3 is a circuit block diagram of a power supply device having an AC standby function.

10‧‧‧Power supply

11‧‧‧Filter circuit

12‧‧‧Rectifier circuit

13‧‧‧Power Factor Correction Circuit

20‧‧‧Switch Module

21‧‧‧First switching unit

22‧‧‧Second switching unit

23‧‧‧ Third switching unit

30‧‧‧Monitoring module

31‧‧‧Processing unit

310‧‧‧AC signal detection circuit

311‧‧‧First processor

312‧‧‧second processor

313‧‧‧Optocoupler

32‧‧‧Power Monitoring Unit

321‧‧‧First detector

322‧‧‧Second detector

323, 324‧‧‧Optocoupler

33‧‧‧First loop switch

34‧‧‧Second circuit switch

340‧‧‧ drive circuit

40‧‧‧Power Module

41, 42‧‧‧Power Converter

Claims (9)

An AC backup power supply system includes a power supply, a switching module and a monitoring module; wherein: the power supply has an input power circuit; the power supply is mainly composed of a filter circuit, a rectifier circuit and a a power factor correction circuit; the switching module has a first switching unit and a second switching unit, wherein the input ends of the first and second switching units are respectively connected to a main AC power source and a backup AC power source; The output end of the second switching unit is switchably connected to the input power circuit of the power supply; the monitoring module includes: a processing unit, and the processing unit is respectively connected to the filter circuit through an AC signal detecting circuit The output end of the rectifier circuit is connected; a power monitoring unit has an input end and an output end, wherein the input end is respectively connected with the main and backup AC power source, and the output end thereof is connected with the processing unit; a first loop switch, Controlled by the processing unit to be turned on and off, which is connected in series to the input power circuit between the switching module and the power supply; The switch is an electronic switch controlled by the processing unit to be turned on and off in parallel with the first circuit switch; wherein when the input power of the input power circuit is abnormal, the processing unit first disconnects the first circuit switch, The second circuit switch is turned on in a state where the input power supply circuit has no current. In the AC backup power supply system of claim 1, the first circuit switch is mainly composed of a relay; the second circuit switch is mainly composed of an AC switch controller, and the gate is transmitted through a driving circuit. Monitoring mode The processing unit of the group is connected. The switchover module further includes a third switching unit between the first and second switching units and the power supply device, wherein the first switching unit is mainly composed of two The relays REL1, REL2 are composed, and the two relays REL1, REL2 respectively have a common terminal, and are respectively connected to the two power lines of the main AC power source, and the two relays REL1, REL2 respectively have a normally open contact and a normally closed contact; The second switching unit is mainly composed of two relays REL3 and REL4, and the two relays REL3 and REL4 respectively have a common end, and are respectively connected with the two power lines of the backup AC power source, and the two relays REL3 and REL4 respectively have a common An open contact and a normally closed contact; the third switching unit is mainly composed of two linked relays REL5 and REL6, and the two relays REL5 and REL6 respectively have a common end and are connected to the input power supply loop of the power supply. The two relays REL5 and REL6 respectively have a normally open contact and a normally closed contact, and respectively have a normally open contact with the relays REL1, REL2, REL3, REL4 of the first and second switching units, Normally closed contact connection. The communication backup power supply system of any one of claims 1 to 3, wherein the processing unit of the monitoring module comprises a first processor and a second processor connected to each other, the first processor and the power source respectively The monitoring unit is connected to the switching module. The power supply monitoring unit of the monitoring module includes a first detector and a second detector, and the input ends of the first and second detectors are respectively associated with the main AC power supply The AC power connection is connected, and the output ends of the first and second detectors are connected to the first processor of the processing unit. In the AC backup power supply system of claim 5, the first and second detectors are respectively connected to the first processor through an optical coupler; the first processor is coupled to the first processor through the optical coupler Two processor connections. The AC backup power supply system of claim 6, further comprising a power module, the power module comprising two power converters, wherein the input ends of the two power converters are respectively connected to the main AC power source and the backup AC power source The output ends are respectively connected to the first and second detectors and connected to the first and second processors. In the AC backup power supply system described in claim 7, the two power converters are a flyback power converter. In the AC backup power supply system of claim 4, the first loop-open relationship is controlled by the first processor of the processing unit to open and close.