JP2015002669A - Voltage abnormality protection circuit for uninterruptible power supply system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an uninterruptible system with stable quality and safety by overcoming defects of a monitoring circuit in a conventional uninterruptible power supply system.SOLUTION: In a voltage abnormality protection circuit for an uninterruptible power supply system, a rectification unit, a filter unit, a battery unit, at least one voltage regulation unit and at least two voltage monitoring units are connected in order. The voltage regulation unit includes at least one voltage drop element and a bypass switch unit connected to the voltage drop element in parallel. The voltage monitoring units are connected to an input side and an output side of the voltage regulation unit, respectively, and used for monitoring voltages at the input side and the output side of the voltage regulation unit, thereby controlling the rectification unit provided in one terminal of an external power source, a breaker and the bypass switch unit.

Description

  The present invention relates to a voltage abnormality protection system for a DC power supply device, and more particularly to a circuit used by a DC power supply device to control a voltage applied to a load.

  When the commercial power supply is in a normal state, the uninterruptible power supply system is connected to the commercial power supply. Normally, the SCR (silicon control rectifier) is used as a rectifier, so that power can be supplied to the load side and at the same time higher. The backup battery can be quickly charged with a voltage, but the above-mentioned high voltage must be further passed through a step-down device such as a DC / DC power converter in order to make the voltage suitable for the demand on the load side. Don't be.

  When a power failure occurs in the commercial power supply, the uninterruptible power supply system automatically switches, and the load side is switched to the power supply by the backup battery. At this time, the backup battery is also connected to the load side via the step-down device. When power is supplied, the power of the backup battery is continuously consumed, and the load side also falls into a trap where the operation stops soon after the commercial power supply fails. Therefore, the backup battery has to add a bypass switch, and it is necessary to continuously supply power to the load side through this, but if the bypass switch fails only by installing a single bypass switch, The bypass cannot be conducted, and power cannot be supplied.

  Also, when the commercial power supply is restored after a power failure for a while, the uninterruptible power supply system charges the backup battery at a high voltage and supplies power to the load side, but if the bypass switch restores the commercial power supply If the switch is not switched in a timely manner, the high voltage of the backup battery is supplied directly to the load side via the bypass switch, the load side equipment is damaged, and the uninterruptible power supply system has an overvoltage protection mechanism. By further operating and shutting off the rectifier, the power consumption of the backup battery is further accelerated, and finally power cannot be supplied for a long time.

  From the above, the equipment on the load side is important and expensive, and the backup battery is also an expensive investment item. Therefore, in an uninterruptible power system, there are three types of situations such as power outage, recovery, and normal operation. However, overvoltage or undervoltage abnormality may occur on the DC side, and it is well known that the voltage abnormality protection circuit of these DC power supply facilities is not considered for related abnormal situations.

  A complete protection circuit fully utilizes the power of the battery during a power failure, protects the load from overvoltage during recovery, and prevents damage to the load and the battery due to a rectifier failure or an external power supply overvoltage during normal operation It is.

  An object of the present invention is to overcome the disadvantage that a protection circuit against abnormal voltage in a conventional uninterruptible power supply system is incomplete and lacks reliability.

  To achieve the above object, the present invention includes a circuit breaker connected to an external power source, a rectifier unit connected to the circuit breaker and outputting a DC voltage to the output side, and a filter connected to the output side of the rectifier unit. A unit, a battery unit connected to the output side of the rectifying unit and installed in parallel with the filter unit, at least one step-down element and a bypass switch unit connected in parallel to the step-down element, of which the step-down element Is connected in series between the battery unit and the load, and the bypass switch unit is connected in parallel to at least one voltage regulation unit in which at least two bypass switches are connected in series to at least one bypass switch, and the voltage At least two power supplies connected to the input and output sides of the adjustment unit respectively. It provides a voltage abnormality protection circuit of an uninterruptible power supply system encompassing and monitoring unit.

  The feature of the present invention is that the device in the voltage regulation unit and the voltage monitoring unit are doubled to prevent uncontrollability, improve the reliability of the overall monitoring function, and the battery or load equipment due to overvoltage is burned out or low voltage It can be ensured that a shutdown accident will not occur.

FIG. 1 is a block diagram showing the present invention. FIG. 2 is a circuit schematic diagram (1) showing a monitoring node according to the present invention. FIG. 3 is a circuit schematic diagram (2) showing the monitoring node according to the present invention. FIG. 4 is a schematic circuit diagram showing monitoring according to another embodiment of the present invention. FIG. 5 is a circuit schematic diagram showing a dual circuit according to a third embodiment of the present invention.

  The objects, technical contents, features, and the objects of the present invention can be achieved by describing the configuration of the present invention and how to combine and use the same in detail below with reference to the drawings by specific embodiments. You can more easily understand the effect.

  With reference to what is illustrated in FIG. 1 and FIG. 2, the voltage abnormality protection circuit E of the uninterruptible power supply system according to the present invention mainly includes a rectification unit 1, a filter unit 2, and a battery unit 3 in configuration. And a voltage adjustment unit 4, a voltage monitoring unit 5, and a circuit breaker 6.

  First, the circuit configuration and effect for supplying power according to the present invention will be described with reference to FIGS. 1 and 2. The circuit breaker 6 is connected to one end of an external power source 7 such as a commercial power source, and the circuit The circuit breaker 6 is set to be normally closed (normally closed). Among them, the circuit breaker 6 can be further connected to the rectifying unit 1 by connecting a fuse 9 in series, whereby the circuit breaker 6 can be connected. The breaker 6 can control the breaking of a serious accident such as overvoltage, and the breaker 6 is a controllable electronic breaker such as an electromagnetic or non-fuse (NFB). In the example, a non-fuse breaker is used.

  The rectifying unit 1 is implemented by a controllable semiconductor switch such as a silicon controlled rectifier (SCR) or an insulated gate bipolar transistor (IGBT), connected to the circuit breaker 6, and outputs a DC voltage on the output side, In the present embodiment, the filter unit 2 is connected in parallel to the output side of the rectifying unit 1 with a capacitor for filtering in the present embodiment, the battery unit 3 is connected to the output side of the rectifying unit 1, The non-fuse breaker 31, the fuse 32, and the battery 33 are connected in series, and are arranged in parallel with the filter unit 2, of which one end of the filter unit 2 and one end of the battery unit 3 are connected to each other. , Manual load current selector switch S1 and S2, respectively, so that workers can easily check The manual load current changeover switch S1 is used to insulate the power of the battery unit 3, and the manual load current changeover switch S2 is used to insulate the power of the rectifying unit 1. It is used.

  Next, the circuit configuration and effect for monitoring the voltage of the present invention will be described with reference to FIG. 3. Since the load 8 always requires a high starting current, the voltage adjusting unit 4 In the embodiment, the DC / DC power converter that cannot provide an instantaneous large current is used, and the step-down elements 41a to 41n and the bypass switch unit 42 connected in parallel to the step-down elements 41a to 41n are implemented. The elements 41a to 41n are provided in series and installed between the battery unit 3 and the load 8, and the bypass switch unit 42 is connected in parallel to these step-down elements 41a to 41n. The bypass switch unit 42 is connected in series to two bypass switches 42a and 42b connected in parallel. The bypass switches 42c and 42d are connected in series, and these bypass switches 42a, 42b, 42c and 42d are each implemented by a controllable electronic switch such as an electromagnetic switch, and the like. Bypass switches 42a and 42b are normally open (normally open, non-conducting), and these bypass switches 42c and 42d are normally closed so that the voltage adjustment unit 4 is used for voltage adjustment of the load 8, of which One end of the voltage adjustment unit 4 is also provided with a manual load current changeover switch S3 in order to insulate the voltage adjustment unit 4 from other elements so that an operator can easily check.

  If the element of the rectifier unit 1 fails or the mechanism of the circuit breaker 6 fails and does not function, and the voltage monitoring unit 5 also fails simultaneously as shown in FIG. In order to prevent the situation in which the connection of the battery unit 3 cannot be interrupted and an overvoltage occurs and damages the equipment of the battery unit 3 or the load 8, two voltage monitoring units 5a and 5b are installed as shown in FIG. Among them, these voltage monitoring units 5a and 5b are installed on the input side and the output side of the voltage adjustment unit 4, that is, the first node a and the second node b, respectively, so that the voltage adjustment unit 4 monitors the voltage values at the input side and output side, and in these voltage monitoring units 5a and 5b, The circuit breaker 6, the rectifier unit 1, and drive circuits (not shown) that individually control the bypass switches 42 a, 42 b, 42 c, and 42 d are provided, so that the circuit breaker can be used at the appropriate time. 6. In order to control the rectifying unit 1 and the bypass switch unit 42 and more accurately measure the current state of these bypass switches 42a, 42b, 42c and 42d, the voltage monitoring units 5a and 5b Furthermore, by incorporating the state auxiliary nodes (not shown) of these bypass switches 42a, 42b, 42c and 42d into the connection with these voltage monitoring units 5a and 5b, the whole of the present invention has a more accurate monitoring effect. Can be achieved.

  The working steps under different circumstances of the present invention will be described below with continued reference to FIGS.

  When the uninterruptible power supply system is in an abnormal state, the external power supply 7 charges the battery unit 3 with the rectifying unit 1 and supplies power to the load 8. When an abnormality occurs in the external power supply 7 and power supply is stopped, the uninterruptible power supply system automatically supplies power from the battery unit 3 to the load 8 via the voltage adjustment unit 4. These voltage monitoring units 5a and 5b monitor the voltage of the first node a at the same time, and the first node a is set to a predetermined critical value in order to prevent the voltage value from being low and consuming the power at an early stage. When the voltage value is lower than the voltage value, these bypass switches 42a and 42b are simultaneously controlled to conduct in a timely manner. Not only can the power of the power station 3 be continuously supplied to the load 8 via these bypass switches 42a, 42b, 42c and 42d, but it operates normally because only a single bypass switch in the known art is installed. It is also possible to prevent the battery power from being sufficiently exerted, and as a result, the battery unit 3 is smoothly charged, and during the period from the power failure until the external power source 7 is restored, the load 8 By supplying power to the battery unit 3, the battery unit 3 is sufficiently effective during backup.

  When the external power supply 7 is restored, the voltage monitoring units 5a and 5b immediately shut off the bypass switches 42a and 42b, so that the external power supply 7 is continuously connected to the battery unit 3 at a high voltage. The battery is charged, and power is continuously supplied to the load 8 through the step-down elements 41a to 41n normally.

  Further, if the bypass switches 42a and 42b after the restoration are not all cut off normally, the high voltage of the first node a directly supplies power to the load 8 via the bypass switch unit 42, and the load 8 Another effect provided by the present invention is that these voltage monitoring units 5a and 5b simultaneously monitor the voltage of the second node b, because overvoltage may occur and the equipment of the load 8 may be damaged. That is, as soon as it finds that the voltage value of the second node b is high, the second node b does not become an overvoltage by controlling the bypass switches 42c and 42d that are normally closed. So that the circuit breaker 6 or the rectifying unit 1 is not interrupted again, effectively preventing a long-time power outage of the load, Kigaibu voltage 7, this time, are feeding this like buck elements 41a to 41n with respect to the load 8 through safely and reliably.

  In addition, when the switching of the bypass switches 42c and 42d also fails and cannot be normally shut off, the voltage monitoring units 5a and 5b immediately shut off the circuit breaker 6 and the rectifier unit 1 to load the load. 8 Protect the equipment from damage and send a signal to the control room via an alarm element (not shown) such as a warning node provided in each of these voltage monitoring units 5a and 5b to issue an alarm. Or a warning lamp is installed and flashed to notify the worker to check immediately.

  Next, as shown in FIG. 4, in the second embodiment according to the present invention, another voltage adjusting unit 4 is added, and the voltage adjusting units 5a and 5b and the voltage adjusting unit added in the present embodiment are added. The connection method with the unit 4 is similar to that of the above-described embodiment, but the difference is that the third node c is further included between the two voltage regulation units 4, and the third node c Are connected to these voltage monitoring units 5a and 5b, respectively, so that these voltage monitoring units 5a and 5b connect the first node a and the third node c to one of the voltage adjustment units 4, respectively. The input voltage and the output voltage are monitored simultaneously and individually, and the third node c and the second node b are respectively connected to the input voltage of the other voltage regulation unit 4. It is simultaneously and individually monitored and as the output voltage.

  Therefore, the effect of the second embodiment is that only the single voltage adjustment unit 4 is installed in the above-described embodiment, and a large change in the output voltage (for example, the output voltage is switched once in the switching step). The range of fluctuations that occur in the circuit is about 10%), which has an unfavorable effect on the load in the control and stability of the circuit. The invention is improved as a two-stage step-down control, that is, the voltage critical value of each node is monitored, and the bypass switch unit 42 is turned on and off based on the critical value of each node (for example, the output voltage). The range of fluctuation caused by adjusting each before and after each is 5%), so that precise output voltage control has been achieved. By installing the adjustment unit 4, it is also possible to achieve the control of a more accurate output voltage.

  Further, as shown in FIG. 5, the third embodiment according to the present invention is implemented in a double type (or multiple type) including the voltage abnormality protection circuit E of two uninterruptible power supply systems. The voltage abnormality protection circuit E of the power failure power supply system is connected to the external power supply 7 and connected to the DC bus F to supply power to the load 8. When implemented in this configuration, at least one diode connected in series and a manual switch must be added between the output side and the load 8, respectively. In this embodiment, the diode D1 connected in series and D2 and manual load current change-over switches S4 and S5 are provided respectively. Among these, these diodes D1 and D2 do not generate a circulating current between the voltage abnormality protection circuits E of these uninterruptible power supply systems. These manual load current changeover switches S4 and S5 are respectively used to manually turn on / off and insulate at the time of inspection.

  From the above, since the influence caused by the voltage abnormality of the uninterruptible power supply system is related to each other, the present invention is a complete protection circuit considering the countermeasures due to the risk of the entire circuit operation. There are such advantages.

  1. Duplicate bypass switch unit (bypass switches 42c and 42d connected in series with bypass switches 42a and 42b connected in parallel) makes it impossible to conduct or shut off without a single switch functioning, so battery backup aging is effective It can be prevented that the load cannot be exhibited or the load is damaged due to the output of overvoltage.

  2. By controlling the respective switches (rectifier unit 1, bypass switches 42a, 42b, 42c and 42d, and circuit breaker 6) individually and independently by the duplicated voltage monitoring units (voltage monitoring units 5a and 5b), overvoltage In addition, the low voltage can effectively prevent damage to the load equipment and the battery unit, and the power supply quality and safety of the uninterruptible power supply system can be improved.

  3. When an overvoltage or undervoltage occurs, an alarm is issued so that an operator can immediately check.

DESCRIPTION OF SYMBOLS 1 Rectification unit 2 Filter unit 3 Battery unit 31 Non-fuse breaker 32 Fuse 33 Battery 4 Voltage adjustment unit 41a-41n Step-down element 42 Bypass switch unit 42a Bypass switch 42b Bypass switch 42c Bypass switch 42d Bypass switch 5 Voltage monitoring unit 5a Voltage monitoring Unit 5b Voltage monitoring unit 6 Circuit breaker 7 External voltage 8 Load 9 Fuse a First node b Second node c Third node D1 Diode D2 Diode E Uninterruptible power supply system voltage abnormality protection circuit F DC bus S1 Manual load current selector switch S2 Manual load current selector switch S3 Manual load current selector switch S4 Manual load current selector switch S5 Manual load current selector switch

Claims (4)

A circuit breaker connected to an external power source;
A rectifying unit connected to the circuit breaker and outputting a DC voltage to the output side;
A filter unit connected to the output side of the rectifying unit;
A battery unit connected to the output side of the rectifying unit and installed in parallel with the filter unit;
At least one step-down element and a bypass switch unit connected in parallel to the step-down element, wherein the step-down element is connected in series between the battery unit and a load, and the bypass switch unit is connected in parallel At least one voltage regulation unit in which two bypass switches are connected in series to at least one bypass switch;
A voltage abnormality protection circuit for an uninterruptible power supply system, comprising at least two voltage monitoring units respectively connected to an input side and an output side of the voltage adjustment unit.   The voltage monitoring unit includes a drive circuit that individually controls the circuit breaker, a drive circuit that individually controls the rectifier unit, or a drive circuit that individually controls each bypass switch. The voltage abnormality protection circuit of the uninterruptible power supply system according to 1.   The voltage abnormality protection circuit of the uninterruptible power supply system according to claim 1, wherein each of these voltage monitoring units has an alarm element.   The step-down elements are diodes, the bypass switches are controllable electronic switches, and the circuit breaker is a controllable electronic switch connecting fuses in series. The voltage abnormality protection circuit of the uninterruptible power supply system according to claim 1, wherein is a controllable semiconductor switch.