JP5970216B2 - Converter device - Google Patents

Description

  Embodiments described herein relate generally to a converter device.

  For example, a capacitor input type converter device rectifies an AC input via a bridge-connected rectifying element group and supplies power via a smoothing capacitor. In this case, in order to prevent an inrush current from flowing when the power is turned on, it is common to connect an inrush current prevention resistor in series and short-circuit the inrush current prevention resistor to supply power to the load when the terminal voltage of the capacitor is stabilized. Has been done.

  However, if the terminal voltage of the capacitor is stabilized and power is supplied to the load by preventing the inrush current when the power is turned on as described above, if the terminals of the inrush current prevention resistor are not short-circuited, the load The voltage supplied to the voltage decreases by the voltage shared by the inrush current prevention resistor. At this time, depending on the load, the power supply state may be automatically cut off due to a drop in the power supply voltage. Then, the terminal voltage of the capacitor rises again, and power supply to the load becomes possible. When the power is supplied, the same phenomenon as described above occurs again in the load and the power is cut off. Thereafter, the above-described power interruption is repeated. As a result, there is a problem that the inrush current repeatedly flows through the inrush current prevention resistor every time the load is turned off and the energization state is changed.

  In order to deal with such problems, conventionally, for example, an inrush current prevention resistor is determined by measuring the terminal voltage or inrush current of a capacitor serving as a DC output and determining whether or not there is an abnormality in power supply to the load. There is something to protect.

  However, in such a configuration, whether or not the protection operation is performed by measuring the DC output voltage or the load current and determining whether the voltage or current level exceeds the allowable range of the inrush current prevention resistor. Therefore, it is necessary to provide a measurement system configuration and to consider the measurement accuracy problem of the measurement system.

JP 2006-340532 A Japanese Patent No. 3724523 US Pat. No. 7,929,323

  Therefore, even when the power supply state to the load and the power cut-off state that occur in the power supply state occur repeatedly, the inrush current prevention resistor can be protected quickly with a simple configuration without measuring voltage or current. An object of the present invention is to provide a converter device that can be used.

The converter device of this embodiment is connected between a positive side and a negative side of the DC output unit in a converter device that receives an AC power supply and outputs DC power from a DC output unit via a semiconductor rectifier element group. A capacitor and a positive output terminal of the semiconductor rectifier element group and a positive output terminal of the DC output unit, or a negative output terminal of the semiconductor rectifier element group and a negative output terminal of the DC output unit. Inrush current prevention resistor connected between, a switch connected in parallel with the inrush current prevention resistor, and electric power for detecting whether the power is supplied or cut off to the load connected to the DC output unit Supply state detection means, transition number counting means for counting the number of transitions from the power supply state to the power cut-off state within a predetermined determination period for the load, and a value counted by the count means Wherein said that the switch has a abnormal state judging means for judging an abnormal state that is not short-circuited when it exceeds a preset threshold.

Electrical configuration diagram showing the first embodiment Electrical configuration diagram showing the second embodiment Electrical configuration diagram showing the third embodiment Electrical configuration diagram showing the fourth embodiment

Hereinafter, a plurality of embodiments will be described with reference to the drawings. In addition, in each embodiment, the same code | symbol is attached | subjected to the substantially same component, and description is abbreviate | omitted.
(First embodiment)
FIG. 1 shows a converter device 1 that feeds a DC output for a general load. The converter device 1 includes a rectifier circuit 2, an inrush current preventing resistor 3, a relay 4, a smoothing capacitor (smoothing capacitor) 5, and the like. The rectifier circuit 2 is a full-wave rectifier circuit in which a plurality of diodes are bridge-connected, and an AC input side is connected to a single-phase or multi-phase AC power source 7 via a power supply cutoff circuit 6. On the DC output side of the rectifier circuit 2, the positive terminal is connected to one terminal of the smoothing capacitor 5 via the inrush current prevention resistor 3, and the negative terminal is connected to the other terminal of the capacitor 5.

  The relay 4 as a switch is connected in parallel to the inrush current prevention resistor 3 and is controlled to be turned on and off at a predetermined timing by a control unit (not shown). Both terminals of the capacitor 5 are DC output terminals and are connected to a load 9 via an output cutoff circuit 8. The operation state of the load 9 is monitored by the protection circuit 10, and when the input voltage decreases or becomes excessive as an element that makes the operation state unstable, the load 9 is connected to the output cutoff circuit 8 via the output circuit 11 as a protection operation. Output a shutoff control signal.

  The counter 12 functions as means for counting the number of transitions. The cutoff control signal is input from the protection circuit 10, and the signal for detecting the operating state of the load 9 is input from the determination circuit 13 that detects the state of the output cutoff circuit 8. The The determination circuit 13 functions as power supply state detection means, periodically samples to determine the operation state of the output cutoff circuit 8, and outputs a signal for determining the operation state of the load 9 to the counter 12. . When the counter 12 receives a signal indicating that the power is supplied to the load 9 from the determination circuit 13, that is, an operating state, and receives a cutoff control signal from the protection circuit 10, the counter 12 shuts off the power from the operating state, that is, the power supply state. A transition to a state is detected and counted as one transition. The count value of the number of transitions by the counter 12 is counted as the number of transitions within a predetermined period stored and set in advance.

  The abnormal state determination circuit 14 functions as an abnormal state determination unit, and the count value of the number of transitions is input from the counter 12. The abnormal state determination circuit 14 stores in advance a count value for determining an abnormal state as a threshold, and determines the abnormal state when the count value input from the counter 12 exceeds the threshold. The abnormal state determination circuit 14 is provided with a configuration as a power supply cutoff unit and an input unit cutoff unit, and performs a power supply cutoff operation to the output cutoff circuit 8 via the output circuit 11 when an abnormal state is determined. And control to interrupt the AC input to the power supply cutoff circuit 6.

  The output circuit 11 controls the power supply state by turning on the output cut-off circuit 8 in a state where a signal instructing the power supply operation to the output cut-off circuit 8 is given from both the protection circuit 10 and the abnormal state determination circuit 14. When one or both of them give a signal for instructing a cutoff operation, the output cutoff circuit 8 is turned off to control the power cutoff state.

Next, the operation of the above configuration will be described.
By operating the converter device 1, DC power is supplied from the AC power source 7 to the load 9. In the converter device 1, when the operating power is turned on, the power supply cutoff circuit 6 is turned on. The input from the AC power source 7 is rectified in the rectifier circuit 2 and a DC output is generated between the DC output terminals. At this time, the relay 4 is held in the OFF state, and the DC output flows through the inrush current preventing resistor 3 and charges the capacitor 5. The current due to the DC output of the rectifier circuit 2 is limited by the inrush current prevention resistor 3, the capacitor 5 is charged with a time constant determined by the product of the resistance value of the inrush current prevention resistor 3 and the capacitance value of the capacitor 5, and the terminal voltage is DC. It rises until it becomes the same level as the output. In this way, when the output voltage rises while suppressing the inrush current to the capacitor 5 when the power is turned on, the relay 4 is turned on by the control circuit, and the terminals of the inrush current preventing resistor 3 are short-circuited. It becomes. As a result, the direct current output from the rectifier circuit 2 is supplied directly to the output terminal via the capacitor 5. Then, the output cutoff circuit 8 is turned on to supply a DC output to the load 9.

  When operating normally as described above, the inrush current to the capacitor 5 can be suppressed by the action of the inrush current preventing resistor 3 when the power is turned on, and the input to the load 9 side is suppressed. Can be prevented.

  Next, in the case of normal operation as described above, after the power is turned on, the inrush current is suppressed, and the terminal voltage of the capacitor 5 reaches a predetermined voltage, and then the load 9 is fed. A problem and its avoidance operation when the relay 4 fails for some reason and does not turn on will be described. In the state where power is supplied to the load 9, an ON signal is output from the protection circuit 10 and the abnormal state determination circuit 14 to the output circuit 11, and the output cutoff circuit 8 is turned on. This is detected and a signal indicating a power supply state to the load 9 is output to the counter 12.

  First, when the relay 4 is not operated, that is, in the off state, when the output cutoff circuit 8 is turned on, a DC output is supplied to the load 9 with the inrush current preventing resistor 3 connected. become. In this case, assuming that the load 9 is a resistance load, the voltage supplied to the load 9 is the resistance voltage division of the load 9 in the series circuit of the inrush current prevention resistor 3 and the load 9 resistance. That is, a voltage lower than the voltage supplied when the relay 4 is normally turned on is supplied. Since the capacitor 5 is charged up to the DC output voltage of the rectifier circuit 2 before the power supply to the load 9 is started, when the output cutoff circuit 8 is turned on and the power supply to the load 9 is started, the resistance component of the load 9 and The voltage decreases with a time constant depending on the capacitance of the capacitor 5.

  Then, in the load 9, the operating voltage cannot be secured because the supplied voltage decreases. When the voltage drop of the load 9 is detected and the voltage is lower than a predetermined operating voltage, the protection circuit 10 outputs a cutoff control signal, turns off the output cutoff circuit 8 through the output circuit 11, and simultaneously outputs the cutoff control signal to the counter 12. To do. Since the cutoff control signal is input to the counter 12 while the signal indicating the power supply state of the load 9 is input from the determination circuit 13, the counter 12 increments the count value by “1” on the assumption that the state has changed to the power cutoff state.

  When the output cutoff circuit 8 shifts to the OFF state, the charging current flows through the inrush current prevention resistor 3 in the capacitor 5, and the terminal voltage of the capacitor 5, that is, the DC output, rises again until it becomes equal to the DC output of the rectifier circuit 2. However, since the operating voltage of the load 9 is reached again before the terminal voltage of the capacitor 5 recovers, the output cutoff circuit 8 is turned on. At this time, the relay 4 is still out of order and remains in the OFF state, so that the supply voltage to the load 9 decreases again.

  Thereafter, the above operation is repeated, and the power supply state to the load 9 and the power cut-off state are alternately repeated. Since the counter 12 increments the count value every time the power shut-off state occurs, the count number increases in accordance with the number of occurrences of the power shut-off state until reaching a predetermined time. When a certain time has elapsed, the count value is output to the abnormal state determination circuit 14.

  In the abnormal state determination circuit 14, when the count value within a predetermined time exceeds the abnormality determination count value that is a preset threshold value, it is determined that the state is abnormal, and the output cutoff circuit 8 on the output side is turned off. Then, the power supply cutoff circuit 6 on the input side is turned off. As a result, the power supply state to the load 9 and the power cut-off state are repeatedly generated, so that the current to the inrush current prevention resistor 3 is overheated or burned out without causing a problem such as overheating. Can be protected.

  In the above-described embodiment, when an abnormal state due to a failure in the OFF operation of the relay 4 is determined, both the output cutoff circuit 8 and the power cutoff circuit 6 are turned off by the abnormal state determination circuit 14. However, the present invention is not limited to this, and only one of them may be turned off.

(Second Embodiment)
FIG. 2 shows the second embodiment. Hereinafter, parts different from the first embodiment will be described. In the second embodiment, the setting unit 16 stores data for a predetermined period stored and set in advance in the counter 12 and threshold data stored and set in advance for determining an abnormal state in the abnormal state determination circuit 14. It is set as the configuration. In addition, when an abnormal state is determined by the abnormal state determination circuit 14, a warning output unit 17 for outputting a warning to the outside is provided.

  That is, the setting unit 16 has a function as a period setting unit and a threshold setting unit. Based on the resistance value data of the inrush current prevention resistor 3 and the capacitance value data of the capacitor 5, the above-described abnormal state is detected. When this occurs, a predetermined period and a threshold value are set as determination conditions for safely stopping the inrush current preventing resistor 3 and other components.

  In the above case, various configurations can be adopted as the configuration of the setting unit 16. For example, when a resistance value of the inrush current prevention resistor 3 and a capacitance value of the capacitor 5 are input, a fixed period and a threshold value necessary for abnormality determination are calculated based on these data and output as set values. It is. In this case, it is also possible to set a predetermined time and a threshold corresponding to a change with time by setting in advance information for estimating a change with time of the resistance value and the capacitance value.

  Further, the configuration of the setting unit 16 is calculated by measuring and inputting the resistance value of the inrush current preventing resistor 3 and the capacitance value of the capacitor 5 in order to accurately set a certain time and a threshold corresponding to a change with time. Alternatively, it is possible to set a fixed time and a threshold corresponding to a change with time based on data measured at an appropriate timing by providing a configuration capable of automatic measurement.

  The warning output unit 17 functions as a warning output means. When the abnormal state determination circuit 14 determines an abnormal state, an abnormal state determination signal is input, and in response to this, an abnormality occurs via a signal line or the like. A notification operation is performed with the state as a warning. In addition to notifying the outside, a sound output unit can be provided as a warning operation to generate an alarm sound. Alternatively, a warning display unit can be provided to display a warning.

  By adopting such a configuration, it is possible to set a fixed period and threshold value based on accurate data corresponding to each device, compared to the case of setting and storing in advance, and more accurately when an abnormal condition occurs. Can respond.

Further, when an abnormal state occurs, the warning output unit 17 can display a warning to the user, sound an alarm, or notify that an abnormality has occurred in a remote place.
In the above-described embodiment, the configuration including both the setting unit 16 and the warning output unit 17 is shown. However, a configuration including either one of the setting unit 16 and the warning output unit 17 may be employed.

(Third embodiment)
FIG. 3 shows a third embodiment, and the following description will be focused on differences from the second embodiment. This embodiment is different in that a cycle measuring unit 19 as a power supply cycle measuring unit and a power cycle calculating unit is provided instead of the counter 12.

  That is, in the first and second embodiments, in order to determine the abnormal state, the number of transitions from the power supply state to the power cut-off state within a certain time is counted and a threshold value is provided. On the other hand, when the power interruption state occurs from the power supply state and the time until the next power supply state starts is measured as a cycle, an abnormal state occurs when the cycle is shorter than a predetermined cycle threshold It is to be judged.

  If the fixed time is T and the number of transitions is N, the average time interval at that time is T / N, which is a value corresponding to the average period. Therefore, each transition period is measured as a period, and an average period is calculated from a plurality of periods, whereby determination equivalent to that in the first embodiment or the second embodiment can be performed.

  In this case, as described above, the abnormal state can be determined by the average period because the time constant determined by the resistance value of the inrush current preventing resistor 3 and the capacitance value of the capacitor 5 and the operating voltage V of the load 9 are determined. For this reason, when the relay 4 does not operate, the power feeding operation and the interruption operation to the load 9 are repeated almost at a constant cycle.

  According to the third embodiment as described above, in the power supply state from the AC power supply 7, the time from the start of the power supply operation state to the load 9 to the power supply cutoff state and the transition to the power supply operation state again is obtained. Since the abnormal state is determined when the average period obtained from a plurality of periods is measured and the magnitude of the average period becomes shorter than a predetermined threshold, the abnormality determination can be performed easily and quickly.

  In the above embodiment, the average period of the periods measured a plurality of times is calculated and determined. However, in addition to the method of obtaining the average period, for example, the tendency of the change in the period value gradually decreases. The abnormal state can be determined by determining the tendency to go, and the abnormal state can also be determined from the maximum value or the minimum value of the cycle.

(Fourth embodiment)
FIG. 4 shows a fourth embodiment. The difference from the second embodiment is that an inverter 23 is provided in a power feeding portion from the DC output portion of the converter device 22 to the load 9. In this configuration, a load 9 that is operated by an AC power supply is connected. The inverter 23 converts the DC output of the converter device 22 into an AC output having a predetermined frequency and supplies power. Further, the inverter 23 is configured to automatically perform a protection operation when the power supply voltage to the load 9 decreases or an abnormal current flows. The counter 12 receives a signal for performing a protection operation from the inverter 23. Further, a signal indicating that converter device 22 is in operation is determined based on an output signal to inverter 23 of abnormal state determination circuit 14.

  Since it is configured as described above, when the converter device 22 is in a power supply state from the AC power supply 7, the abnormal state determination circuit 14 outputs a signal that permits operation to the inverter 23. The operating state of the converter device 22 is determined. Further, when the inverter 23 normally supplies power to the load 9, since the signal indicating the normal state is also input to the counter 12, the counter 12 determines the power supply state of the load 9.

  However, if the relay 4 does not operate after the start and the power feeding operation is continued with the inrush current preventing resistor 3 being interposed, the output voltage to the load 9 decreases as described above, and the inverter 23 is protected. The power supply to the load 9 is stopped. Accordingly, the counter 12 receives the power supply stop signal from the inverter 23, determines the power cutoff state, and increments the count value. Thereafter, when an operation of shifting from the power supply state to the power supply cutoff state repeatedly occurs and the count value exceeds the threshold value, the abnormal state determination circuit 14 determines the abnormal state, and the inverter 23 via the output circuit 11 is determined. A signal is output so as to shift to the power-off state.

  Therefore, the same effect as that of the second embodiment can also be obtained by the fourth embodiment. In addition, by using the function provided in the inverter 23, it is possible to implement with a simple configuration without providing a protection circuit or a determination circuit.

(Other embodiments)
The following modifications other than those described in the above embodiment can be made.
The inrush current preventing resistor 3 and the relay 4 are connected to the positive DC output terminal of the rectifier circuit 2 and the positive terminal of the capacitor 5, and the negative DC output terminal of the rectifier circuit 2 and the negative side of the capacitor 5. The present invention can also be applied to a structure connected to a terminal.

In each of the above embodiments, the relay 4 is provided as a switch, but a semiconductor switching element can be used instead.
In the second embodiment, the setting unit 16 and the warning output unit 17 are provided. However, any one of them may be provided.

In the third embodiment, the case where the present invention is applied to the configuration of the second embodiment has been described. However, the third embodiment can also be applied to the configuration of the first embodiment.
In the fourth embodiment, the case where the inverter 23 is provided in the configuration of the second embodiment has been described. However, the inverter 23 may be provided in the configuration of the first or third embodiment.

  Although several embodiments of the present invention have been described, these embodiments are presented by way of example and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the scope of the invention. These embodiments and modifications thereof are included in the scope and gist of the invention, and are included in the invention described in the claims and the equivalents thereof.

  In the drawings, 1, 15, 18, and 22 are converter devices, 2 is a rectifier circuit, 3 is an inrush current prevention resistor, 4 is a relay (switch), 5 is a capacitor, 6 is a power cut-off circuit, 7 is an AC power source, and 8 is Output cutoff circuit, 9 is a load, 10 is a protection circuit, 12 is a counter (transition frequency counting means), 13 is a discrimination circuit (power supply state detection means), 14 is an abnormal state determination circuit (abnormal state determination means), 16 is Setting unit (period setting unit, threshold setting unit), 17 is an alarm output unit (warning output unit), 19 is a cycle measuring unit (power supply cycle measuring unit, power supply cycle calculating unit), and 20 is an abnormal state determination circuit (abnormal) (State determination means), 23 indicates an inverter.

Claims (8)

In a converter device that takes an AC power supply as input and outputs DC power from a DC output unit via a rectifier circuit,
A capacitor connected between a positive side and a negative side of the DC output unit;
Inrush current connected between the positive output terminal of the rectifier circuit and the positive output terminal of the DC output unit, or between the negative output terminal of the rectifier circuit and the negative output terminal of the DC output unit. Prevent resistance,
A switch connected in parallel with the inrush current preventing resistor;
Power supply state detection means for detecting whether the power supply state or the power cut-off state for a load connected to the DC output unit;
A transition number counting means for counting the number of times the power supply state is changed to the power cutoff state within a predetermined determination period for the load;
A converter device comprising: an abnormal state determination unit that determines an abnormal state in which the switch is not short-circuited when a value counted by the counting unit exceeds a preset threshold value. The converter device according to claim 1,
A converter device comprising period setting means for setting the determination period in the transition number counting means based on circuit constants of the inrush current prevention resistor and the capacitor. The converter device according to claim 1 or 2,
A converter device comprising threshold setting means for setting the threshold in the abnormal state determination means based on the circuit constants of the inrush current prevention resistor and the capacitor. In a converter device that takes an AC power supply as input and outputs DC power from a DC output unit via a rectifier circuit,
A capacitor connected between a positive side and a negative side of the DC output unit;
Inrush current connected between the positive output terminal of the rectifier circuit and the positive output terminal of the DC output unit, or between the negative output terminal of the rectifier circuit and the negative output terminal of the DC output unit. Prevent resistance,
A switch connected in parallel with the inrush current preventing resistor;
Power supply state detection means for detecting whether the power supply state or the power cut-off state for a load connected to the DC output unit;
A power supply cycle measuring means for measuring a power supply cycle from the time when power supply is started from the DC output unit to the load until the time when power supply is resumed after shifting to the power cutoff state;
A power supply period calculating means for estimating a current power supply period based on a plurality of power supply period values obtained from the power supply period measuring means;
An abnormal state determination unit that determines an abnormal state in which the switch is not short-circuited when the current power supply cycle estimated by the power supply cycle calculation unit is shorter than a preset cycle threshold value. Converter device. The converter device according to claim 4,
A converter device comprising period threshold value setting means for setting the period threshold value based on circuit constants of the inrush current preventing resistor and the capacitor. The converter device according to any one of claims 1 to 5,
A converter device comprising: a power cut-off means for cutting off power supply from the DC output unit to a load when the abnormality determination is made by the abnormal state determination means. In the converter apparatus in any one of Claim 1 thru | or 6,
A converter device, comprising: an input section blocking means for blocking an input of the AC power supply when the abnormality determination is made by the abnormal state determination means. The converter device according to any one of claims 1 to 7,
A converter device comprising: warning output means for outputting warning information indicating an abnormal state when the abnormality determination is made by the abnormal state determination means.

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