JP2005229733A - Power supply fault detecting circuit - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a power supply fault detecting circuit capable of detecting a fault in open mode surely in addition to short circuit fault of a switching element while performing fault detection through a simple arrangement. <P>SOLUTION: Power converting circuits 5 and 7 comprising a switching element operating with a DC voltage are provided with step-up circuits 13 and 14, output voltage from the step-up circuit is varied on the basis of a preset duty ratio and a load 2 is driven by operating the power converting circuits 5 and 7 alternately on the basis of the relation of magnitude of the voltage. The power supply fault detecting circuit comprises means 21 and 22 for detecting the currents flowing through two power converting circuits 5 and 7, an operational amplifier 23 for amplifying the difference of currents from two current detecting means 21 and 22, a circuit 24 for integrating an alternate operation signal from the operational amplifier 23, and normal operation judging means 25 and 26 for judging whether a voltage level from the integrating circuit 24 exists within a preset voltage level or not. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention includes a first power conversion circuit including a first power conversion switching element that performs an ON-OFF operation with a DC voltage as an input, and a second power conversion switching element that performs an ON-OFF operation with a DC voltage as an input. A second power conversion circuit is provided on a primary side of a common transformer, a booster circuit is provided in each of the two power conversion circuits, and an output voltage of the at least one booster circuit is set based on a preset duty ratio. A secondary side DC output circuit for supplying power to a load that is generated by alternately operating two power conversion circuits based on the magnitude relationship between the changed voltage and the voltage is provided on the secondary side of the transformer. The present invention relates to a power supply failure detection circuit capable of detecting a failure of a power supply circuit provided in the above.

In the power supply circuit described above, the two power conversion circuits are alternately operated based on a preset duty ratio, whereby adverse effects on the electronic components due to heat generation can be suppressed. However, electronic components constituting the power conversion circuit may fail for some reason during operation, and this failure is quickly detected and the failed power conversion circuit is repaired. . Then, each of the two power conversion circuits is provided with a failure detection circuit for detecting the failure, and the pulse signal input to the gate circuit of the switching element and the output current from the switching element in the failure detection circuit. There is a proposal that is configured to detect and detect that the switching element is short-circuited when the output current from the switching element is detected when the gate signal is a drive stop signal (for example, , See Patent Document 1).
JP 2002-84680 A (FIGS. 2 and 4)

In Patent Document 1, a failure detection circuit is provided in each of the two power conversion circuits, and a configuration in which two of the gate signal to the gate circuit and the output current from the switching element must be detected. Therefore, the entire circuit was complicated.
In addition, when the switching element has failed in the open mode, there is a problem that the switching current does not flow, so that the failure cannot be determined.

  In view of the above-mentioned situation, the present invention intends to solve the problem by detecting a failure with a simple configuration, but also reliably detecting an open mode failure in addition to a short circuit failure of a switching element. It is in the point which provides the power failure detection circuit which can do.

In order to solve the above-mentioned problem, the present invention provides a first power conversion circuit including a first power conversion switching element that performs an ON / OFF operation with a DC voltage as an input, and a second that performs an ON / OFF operation with a DC voltage as an input. A second power conversion circuit including a switching element for power conversion is provided on the primary side of a common transformer, a booster circuit is provided in each of the two power conversion circuits, and the at least one is based on a preset duty ratio. A secondary side DC output circuit for supplying power generated by changing the output voltage of one booster circuit and alternately operating two power conversion circuits based on the magnitude relationship of the changed voltage In a power supply circuit provided on the secondary side of the transformer, current detection means for detecting currents flowing through the two power conversion circuits, respectively An operational amplifier or a comparator for amplifying a difference between the currents from the two current detection means, an integration circuit for integrating the alternating operation signal from the operational amplifier or the comparator and converting it into a voltage value; A normal operation determination means for determining whether or not the voltage value from the integration circuit exists between a preset upper limit voltage value and a lower limit voltage value, and constitutes a power failure detection circuit. ing.
Therefore, the alternating operation signal obtained from the difference between the currents of the power conversion circuit detected by the two current detection means is integrated and converted into a voltage value, and the voltage value is set between the preset upper limit voltage value and the lower limit value. By determining whether or not it exists between the voltage value, it is possible to determine whether it is normal operation or abnormal operation. For example, if one of the switching elements of the power conversion circuit that is operating alternately fails in the open mode, it will deviate from the upper limit voltage value or the lower limit voltage value, and it is determined that there is a failure. can do.

  In order to compare the normal operation discrimination means with the first comparator for comparing the upper limit voltage value with the voltage value from the integration circuit, and the lower limit voltage value with the voltage value from the integration circuit. The second comparator may be used.

  Each of the power conversion circuits may be unitized, and the power conversion circuit units may be configured so as to be freely inserted and removed in a live state with respect to the secondary side DC output circuit for driving a load.

  The two power conversion circuit units and the secondary side DC output circuit can be housed in a casing in a state where the secondary side DC output circuit is located on the back side of the two power conversion circuits. By inserting each power conversion circuit unit arranged on the near side to the fixed secondary side DC output circuit, both can be connected, and each power conversion circuit unit is equipped with power supply A lock mechanism for preventing the connected power conversion circuit unit from being pulled out from the casing unless the switch is turned off may be provided.

  Current detection means for detecting currents flowing through the two power conversion circuits, an operational amplifier or comparator for amplifying a difference between currents from the two current detection means, and from the operational amplifier or comparator An integration circuit for integrating the alternating operation signal and converting it to a voltage value, and determining whether the voltage value from the integration circuit exists between a preset upper limit voltage value and a lower limit voltage value It is possible to discriminate a faulty power conversion circuit simply by providing a normal operation discrimination means, and to simplify the circuit configuration as compared with the case where each of the two power conversion circuits is provided with a fault detection circuit. In addition to this, it is possible to provide a power supply failure detection circuit that can reliably detect even when a switching element fails in an open mode.

  Each power conversion circuit is unitized, and the power conversion circuit unit is configured to be detachable in a live state with respect to the secondary side DC output circuit for driving the load, so that only the failed power conversion circuit unit is removed. Can be repaired, which is advantageous in terms of maintenance. Further, the power supply circuit can be driven in the same manner as before the failure only by replacing the failed unit with a new unit. For example, even when the power conversion circuit unit is connected to the secondary DC output circuit when the power supply switch is forgotten to be turned off (turned off), an arc is generated at the connection between the two and the connection There is no trouble such as welding of parts or damage of elements.

  By simply inserting each power conversion circuit unit arranged on the front side of the secondary DC output circuit fixed in the casing, not only can both be connected quickly, but each power conversion circuit unit Since the lock mechanism can prevent the power conversion circuit unit in the connected state from being pulled out of the casing unless the power supply switch provided is turned off, for example, the power conversion in the extracted live state By accidentally touching the circuit unit with a hand or the like, it is possible to reliably avoid the occurrence of a burn or a trouble due to a short circuit of an electronic device.

FIG. 1 shows a forward type power supply circuit. This power supply circuit is connected to a secondary winding N2 of a common high-frequency transformer (which may be a low-frequency transformer) 1 in an electrically insulated state and is a secondary for supplying DC power to the load 2 Side DC output circuit 3 is connected to the primary winding N1 on the primary side of the common high-frequency transformer 1 in an electrically insulated state, and the common high-frequency transformer 1 is connected by the output of the secondary battery 4. Through the first power conversion circuit 5 for supplying power to the secondary side DC output circuit 3 via the second winding N3 on the primary side of the common high-frequency transformer 1 in an electrically insulated state. In addition, the output of a secondary battery other than the secondary battery 4 (the output size is set to be approximately the same as that of the secondary battery 1 but may be a different output) 6 The secondary side DC output circuit 3 is connected via the common high-frequency transformer 1. And a second power converter circuit 7 for power supply.
Each of the power conversion circuits 5 and 7 includes boosting circuits 13 and 14, and one of the boosting circuits 13 outputs an alternate operation signal from an alternate operation signal generator (not shown) via the photocoupler 15. The other booster circuit 14 outputs an alternate operation signal obtained by inverting the alternate operation signal from the alternate operation signal generator (not shown) by the inverter circuit 27 via the photocoupler 16. Yes. Here, the output voltages of the two booster circuits 13 and 14 are changed, but only the output voltage of one of the booster circuits 13 or 14 may be changed. Each of the power conversion circuits 5 and 7 may use a fuel cell, a solar cell, a nuclear battery or the like as the secondary battery 4 or 6, and is a generator or the like instead of the secondary battery 4 or 6. Also good. Moreover, although what provided the secondary battery in each of the two power conversion circuits 5 and 7 was shown, a common secondary battery may be used. In addition to configuring the power supply unit with a secondary battery, a power conversion circuit may be configured by using a commercial AC power supply and providing a rectifier circuit for rectifying the AC voltage from the commercial AC power supply into a direct current. In addition, it is possible to provide three or more power conversion circuits. In this case, if a power supply circuit is configured by providing at least one power source unit configured with a commercial AC power source and one configured with a DC power source such as a secondary battery, for example, even during a power failure There is an advantage that power can be supplied to the secondary side DC output circuit 3 using a DC power supply. In addition to the forward type as shown in FIG. 1, the power supply circuit may be a flyback type, a full bridge type, a half bridge type, or the like, and may be configured as any type of power supply circuit.

  As shown in FIG. 1, the two power conversion circuits 5 and 7 include gate circuits 8 and 9 to which a control signal from a main control IC (not shown) is input via a drive transformer (not shown). Currents that are activated by gate signals from the gate circuits 8 and 9 and that detect the current flowing through the power conversion circuits 5 and 7 and the FETs 10 and 11 as switching elements connected to the primary winding N1 of the high-frequency transformer 1 Current transformers (which may be composed of other current detection elements such as Hall elements) 17 and 18 as detection means.

Operational amplifiers for connecting the current detection circuits 21 and 22 to the secondary windings K2 and H2 of the current transformers 17 and 18 and calculating and amplifying the difference between the detection currents from the two current detection circuits 21 and 22 23 (or a comparator), an integration circuit (consisting of a resistor 24R and a capacitor 24C) 24 for integrating the alternating operation signal output from the operational amplifier 23 (or the comparator) and converting it into a voltage value, A first comparator 25 for comparing the voltage value from the integration circuit 24 with a preset upper limit voltage value, a voltage value from the integration circuit 24 and a preset lower limit voltage value, The power supply failure detection circuit 12 is configured by providing a second comparator 26 for comparing the two.
2A and 2B show current value signals at points a and b in FIG. 1, that is, current values flowing through the current detection circuits 21 and 22, and these current values are the operational amplifiers 23 (or comparators). FIG. 2C shows an alternate operation signal output at point c in FIG. A voltage waveform (voltage at point d in FIG. 1) converted through the integration circuit 24 is shown in FIG. In this case, the drive times of the two switching elements 10 and 11 are the same, and the output power from the power conversion circuits 5 and 7 rises from the voltage value g1 to the voltage value g2 in FIG. The upper reference voltage e and the lower limit threshold, which are the upper limit threshold values shown in the figure, are alternately repeated by repeating W1) having the rising inclination angle and falling from the voltage value g2 to the voltage value g1 (W2 having the lower right inclination angle). Is maintained between the lower limit reference voltage f and the sawtooth waveform shown in FIG. 2D. However, when an electronic component of at least one of the power conversion circuits 5 and 7, for example, the switching element 11 fails in the open mode, the output voltage from the power conversion circuit 5 is: As shown by the alternate long and short dash line D1 shown in FIG. 2 (d), when the voltage value rises to the right and exceeds the upper reference voltage e, an abnormal signal is output from the first comparator 25, and the display panel (FIG. (Not shown) The lamp is lit, the buzzer is sounded, or both of them are displayed, and the voice is displayed, and the message display section indicates that there is a failure using characters and diagrams By doing so, it is possible to grasp that the power conversion circuit 7 is faulty (abnormal).
Whether the voltage value from the integration circuit 24 from the first comparator 25 and the second comparator 26 exists between the preset upper reference voltage e and the lower reference voltage f. It constitutes normal operation discrimination means for discrimination.

As shown in FIGS. 3 (a) and 3 (b) to FIG. 6, the power supply circuit is composed of a plurality of units that can be brought into a connected state and a disconnected state by insertion and removal so as to be advantageous in terms of maintenance. The unit structure will be described.
First, as shown in FIGS. 3A and 3B, a first output unit 35 (including the secondary side DC output circuit 3 provided on the inner side of the casing 35K in which all the units are accommodated) is provided. The first input unit 36 (provided with the power conversion circuit 5) configured to be detachable with respect to FIG. 3 is disposed on the front side in the casing 35K. Reference numeral 37 shown in the figure denotes a second input unit disposed in the casing 35K in parallel with the first input unit 36. The second input unit 37 is a second input unit different from the first output unit 35. An output unit (not shown) is detachable. Here, the case where the same number of input units and output units, that is, a plurality of pairs (in the figure, two pairs are shown, but three or more pairs may be provided) is shown. The number of output units may be small relative to the number, and vice versa. The casing 35K is set to an ERP-2U (external shape described in Intel-sponsored SSI server specification) size, but is not limited to this size. Further, the two units 36 and 37 are arranged in a state where they are arranged side by side in the vertical direction, but they may be arranged in a state where they are arranged side by side in the left and right direction, and the arrangement of the units 36 and 37 can be freely changed. is there.

The first input unit 36 is connected to an external power supply unit (not shown) via a plug-attached cord 38 that can be inserted and removed from an external power supply. The power is supplied from. Further, the first input unit 36 is provided with a handle 40 for pulling out the unit so that the first input unit 36 can be pulled out to the front side by holding the handle 40. When the first input unit 36 is pulled out, a lock mechanism is provided so that it cannot be pulled out unless the switch 39 is in the OFF state. The locking mechanism protrudes from the front side of the unit to one side plate portion constituting the rectangular cylindrical casing 36B of the first input unit 36, and then extends to the L-shaped movable piece 36C extending to the front side of the unit. A protrusion 36T is provided to be engaged with an opening 35A formed in the casing 35K. Accordingly, the first input unit 36 is inserted into the casing 35K, and when the insertion is completed, the protrusion 36T of the movable piece 36C is locked to the opening 35A of the casing 35K, so that the first input unit 36 is held with the handle 40. It is configured to be in a locked state where 36 cannot be pulled out. In this locked state, the movable piece 36C is rocked to the unit side with the tip of the movable piece 36C, so that the locked state can be released by releasing the projection 36T from the opening 35A. At this time, if the switch 39 is in the ON state, as shown in FIGS. 3B and 5B, the switch 39 comes into contact with the lateral side portion of the switch 39, and the movable piece 36C is swung to the unit side. It can not be operated. That is, the first input unit 36 cannot be removed unless the power supply to the first input unit 36 is cut off. For example, in a configuration in which the first input unit 36 can be removed while power is being supplied, the removed first input unit 36 is in a live state and is exposed to the output unit side of the first input unit 36. A hand etc. accidentally touches the connector for connection (not shown) in the state, and troubles due to burns or short-circuiting of electronic devices may occur, but the power supply was cut off as described above The occurrence of the trouble can be reliably avoided by setting the state.
The second input unit 37 has the same configuration as that of the first input unit 36, and is connected to a power supply unit (not shown) provided outside via a plug cord 38 that can be inserted and removed from an external power supply. By turning on the switch 39B, power is supplied from the power supply unit into the circuit. Further, the second input unit 37 is provided with a handle 40B for pulling out the unit so that the second input unit 37 can be pulled out to the front side with the handle 40B. When the second input unit 37 is pulled out, a lock mechanism is provided so that the switch cannot be pulled out unless the switch 39B is in the OFF state. The locking mechanism projects to the L-shaped movable piece 37 </ b> C extending to the front side of the unit after protruding to the front side of the unit on one side plate part constituting the rectangular cylindrical casing of the second input unit 37. A protrusion 37T is provided to be engaged with the opening 35B formed in 35K.

The insertion / removal structure of the first output unit 35 and the first input unit 36 is shown in FIG. FIG. 6 shows only the boards 35a, 36a of the units 35, 36 and the four male and female connectors 41, 42, 43, 44 provided at the ends of the boards 35a, 36a.
As shown in FIG. 6, a protruding piece 35T that protrudes toward the other substrate is formed at a substantially central portion (in any position) in the width direction of the end of one substrate 35a, and the other substrate 36a A notch 36K is formed at the position corresponding to the projecting piece 35T at the end so that the projecting piece 35T enters and is positioned, and the upper and lower (both sides in the board thickness direction) of the notch 36K are closed. For this purpose, a pair of closing plate members 36H, 36H are attached to the substrate 36a. And the taper parts 35T and 35T for a guide located in the width direction center side are provided in the width direction both sides of this protrusion piece 35T so that the insertion direction front-end | tip of the said protrusion piece 35T may become narrow toward the front end side. Even when the notch 36K enters the projecting piece 35T and the positions of both are slightly deviated, the position of the notch 36K relative to the projecting piece 35T is moved and corrected by the guide action of the taper portions 35T and 35T. Thus, the fitting recesses 42A, 44A of the female connectors 42, 44 can be reliably fitted to the pins 41P, 43P of the male connectors 41, 43.

  A control circuit (not shown) is connected to the one female connector 42, and a main circuit (the power conversion circuit 5) is connected to the other female connector 44. , 44, it is necessary to set the order of connection of the male connectors 41, 43 that are connected to each other. For this reason, it is common to use male connectors with different pin lengths, but this case may be disadvantageous in terms of cost, and as shown in FIG. 6, male pins with the same pin length are used. While using the connectors 41 and 43 of the mold, the control circuit side is connected first only by positioning one connector 43 away from the other substrate 36a in the insertion / removal direction by a set distance L from the end of the substrate 35a. The main circuit is configured to be connected later, but the control circuit may be connected after the main circuit side is connected first. Thus, by controlling the connection timing of the two circuits, that is, the main circuit and the control circuit, even if the switch 39 or 39B is in the active state where the switch 39 or 39B is in the ON state, the input unit 36 or When the input unit 36 or 37 is replaced by inserting a new input unit 36 or 37 or a repaired input unit 36 or 37 into the output unit 35 after the 37 is removed from the output unit 35 (see FIG. 6). (Corresponding to the fitting recesses 42A and 44A of the connectors 42 and 44 and the pins 41P and 43P of the connectors 41 and 43), the connecting portions are welded, and various elements constituting the unit are damaged. It is possible to avoid the occurrence of troubles.

It is a power supply circuit diagram provided with the power failure detection circuit. (A), (b) is a waveform diagram of current at points a and b in FIG. 1, (c) is a waveform diagram of an alternating operation signal, and (d) is a waveform diagram of a voltage from an integration circuit. It is a perspective view which shows the casing which accommodated the power supply circuit, (a) shows the state which turned off the switch, (b) has shown the state which turned on the switch. It is a perspective view which shows the state which pulled out the 1st input unit with respect to the casing. (A) is a left view which shows the principal part of the casing which made the switch OFF state, (b) is a left side view which shows the principal part of the casing which made the switch ON state. It is a perspective view which shows the state just before connecting a 1st input unit and a 1st output unit.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 High frequency transformer 2 Load 3 Secondary side DC output circuit 4, 6 Secondary battery 5, 7 Power conversion circuit 8, 9 Gate circuit 10, 11 Switching element 12 Power supply failure detection circuit 13, 14 Booster circuit 15, 16 Photocoupler 17 , 18 Current transformers 19, 20 Switching elements 21, 22 Current detection circuit 23 Operational amplifier 24C Capacitor 24R Resistance 24 Integration circuit 25, 26 Comparator 27 Inversion circuit 35K Casing 35T, 35T Taper 35, 36 Unit 35a, 36a Substrate 35T, 36T Protruding piece 35A35B Opening 36B Casing 36C Movable piece 36T Protrusion 36K Notch 36H Blocking plate member 37 Input unit 37C Movable piece 37T Protrusion 38 Cord with plug 39, 39B Switch 40, 40B Handle 41, 42, 43, 44 Connector 41P , 43P Pin 42A, 44A Fitting recess 45 Inverting circuit 46, 47 AND circuit 48, 49 Inverting circuit 50, 51 Latch circuit 52, 53 Timer circuit 52A, 53A Holding release signal 54, 55 Short-circuit fault detection circuit K1, H1 Primary side Winding K2, H2 Secondary winding L Set distance N1, N3 Primary winding N2 Secondary winding

Claims (4)

  A first power conversion circuit including a first power conversion switching element that performs an ON-OFF operation with a DC voltage as an input, and a second power conversion including a second power conversion switching element that performs an ON-OFF operation with a DC voltage as an input A circuit is provided on a primary side of a common transformer, a booster circuit is provided in each of the two power conversion circuits, and an output voltage of the at least one booster circuit is changed based on a preset duty ratio, A secondary side DC output circuit for supplying power generated by alternately operating the two power conversion circuits to the load based on the magnitude relationship of the changed voltage is provided on the secondary side of the transformer. In the power supply circuit, the current detection means for detecting the currents flowing through the two power conversion circuits, respectively, and the power from the two current detection means An operational amplifier or a comparator for amplifying the difference between them, an integration circuit for integrating an alternating operation signal from the operational amplifier or the comparator and converting it into a voltage value, and a voltage value from the integration circuit are preset. A power failure detection circuit, comprising: normal operation determination means for determining whether or not the upper limit voltage value exists between the upper limit voltage value and the lower limit voltage value.   The normal operation determining means compares the first comparator for comparing the upper limit voltage value with the voltage value from the integration circuit, and the lower limit voltage value with the voltage value from the integration circuit. The power failure detection circuit according to claim 1, comprising: a second comparator.   The power supply according to claim 1 or 2, wherein each of the power conversion circuits is unitized, and the power conversion circuit units are configured to be freely inserted and removed in a live state with respect to the secondary side DC output circuit for driving a load. Fault detection circuit. The two power conversion circuit units and the secondary side DC output circuit can be housed in a casing in a state where the secondary side DC output circuit is located on the back side of the two power conversion circuits. By inserting each power conversion circuit unit arranged on the near side to the fixed secondary side DC output circuit, both can be connected, and each power conversion circuit unit is equipped with power supply 4. The power failure detection circuit according to claim 3, further comprising a lock mechanism for preventing the connected power conversion circuit unit from being pulled out of the casing unless the switch is turned off.

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