JP2002058255A - Power conversion apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a power conversion apparatus capable of continuing auxiliary charging without being affected by a state of a commercial power source. SOLUTION: The power conversion apparatus comprises an auxiliary charging circuit 7 at an AC input unit, a high power factor converter 2 for starting a converter input circuit after auxiliary charging up to a predetermined voltage is conducted, and an auxiliary charging voltage deciding and discriminating circuit 9 for determining a high or low input voltage and deciding an auxiliary charging completion voltage.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a power conversion device provided with a high power factor converter including a pre-charge circuit, and more particularly to a device that starts by switching a pre-charge completion voltage by judging a state of an input voltage. It is.

[0002]

2. Description of the Related Art FIG.
FIG. 1 is a block diagram showing a power conversion device provided with a conventional high power factor converter described in
2l is a commercial power supply, 22 is a high power factor converter for converting AC power output from the commercial power supply 2l to DC power, 23 is an input switch for connecting the commercial power supply 21 and the high power factor converter 22, 24 is a high power A DC smoothing capacitor in which a DC voltage is stored in order to control the current with the rate converter 22, 25 is an inverter that converts DC power output from the high power factor converter 22 into AC power, and 26 is an output of the inverter 25. The received load 27 is a pre-charging circuit for pre-charging the DC smoothing capacitor 24 with a DC voltage before the high power factor converter 22 is started, and 28 is a signal indicating that the pre-charging circuit 27 has been charged with a sufficient voltage. A preliminary charging completion determination circuit for determining 29 is a preliminary charging switch for connecting the AC power output from the commercial power supply 21 to the preliminary charging circuit 27. A.

FIG. 12 is a flowchart showing the operation of the pre-charge completion determination circuit 28. The processing shown in FIG. 12 is repeated from the start to the end. Pre-charge switch 2
When the power supply 9 is turned on, the pre-charge voltage is read in order to input the AC power from the commercial power supply 21 to the pre-charge circuit 27 (STEP 201). It is determined whether the pre-charge voltage has reached the pre-charge completion voltage (STEP 20).
2) If not, the preliminary charge switch 29 is turned on (STEP 203). Here, the pre-charge completion voltage is obtained by calculating a constant voltage from the accumulated voltage capacity of the DC smoothing capacitor 24 as a determination value.

[0004] The pre-charging circuit 27 converts AC power into DC power and starts pre-charging the DC smoothing capacitor 24. If it is determined in STEP 202 that the pre-charging has been completed, the pre-charging switch 29 is opened (ST
EP204). The operator recognizes that the pre-charging has been completed,
When the input switch 23 is turned on, the high power factor converter 22 starts. The high power factor converter 22 operates by controlling the current supplied from the commercial power supply 21 using the DC voltage charged in the DC smoothing capacitor 24. Next, by starting the inverter 25, the AC power converted from the DC power is supplied to the load 26.

[0005]

Since the conventional power converter is configured as described above, the pre-charging is completed at a constant voltage, so that when the voltage of the commercial power supply is high, the pre-charging is relatively quick. On the other hand, when switching the input circuit to the high power factor converter, the damage to the high power factor converter circuit is large, and in the precharging with the commercial power supply voltage low, the time spent for the precharging is There have been problems such as the length becoming long or not reaching the pre-charge completion voltage.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problems, and determines the measured value of the voltage of the commercial power supply and changes the precharge completion voltage to change the state of the voltage of the commercial power supply. It is an object of the present invention to obtain a power conversion device that can continue precharging without being affected.

[0007]

According to a first aspect of the present invention, there is provided a power conversion apparatus including a precharge circuit provided on an output side of a commercial power supply, and starting a converter after precharging to a predetermined voltage. A preliminary charging voltage determination / determination circuit for determining the precharging completion voltage from the value of the commercial power supply, determining that the voltage of the commercial power supply is within the range for continuing the precharging, and issuing a precharge start command. It is a thing.

[0008] A power converter according to a second aspect of the present invention is provided with a guidance circuit for displaying an operation guidance of completion of preliminary charging.

According to a third aspect of the present invention, there is provided a power converter, wherein a precharge voltage determination / judgment circuit outputs an automatic operation command for starting a converter.

The power converter according to a fourth aspect of the present invention is provided with a pre-charge abnormality detection circuit for detecting whether or not the pre-charge has been completed within a specified time.

The power converter according to a fifth aspect of the present invention is provided with an alarm output circuit for displaying and outputting a precharge abnormality and a current precharge voltage value and a precharge completion voltage value.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiment 1 An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing a power converter according to a first embodiment of the present invention. In the figure, reference numeral 1 denotes a commercial power supply, and 2 denotes a high power for converting AC power output from the commercial power supply 1 to DC power. Power converter 3, an input switch for connecting the commercial power supply 1 and the high power factor converter 2, 4 is a DC smoothing capacitor in which a DC voltage is stored, and 5 is An inverter for converting DC power output from the high power factor converter 2 into AC power; 6 a load receiving the output of the inverter 5; 7 a DC voltage applied to the DC smoothing capacitor 4 before starting the high power factor converter 2 Is a pre-charging circuit for charging.

Reference numeral 8 denotes a precharge switch for connecting the AC power output from the commercial power supply 1 to the precharge circuit 7, and 9 determines a precharge completion voltage from the value of the commercial power supply 1. The precharge completion voltage and the precharge voltage are compared with each other, or it is determined that the voltage of the commercial power supply 1 is within the range in which the precharge is continued, and a precharge command for turning on or off the precharge switch 8 is issued. It is a voltage determination / determination circuit.

Next, the operation will be described. In the present embodiment, the conventional precharge completion determination circuit shown in FIG. 11 is replaced with a precharge voltage determination / determination circuit 11 and the other configuration performs the same operation.
FIG. 2 is a flowchart showing the operation of the pre-charge voltage determination / determination circuit 9, and the processing shown in FIG. 2 is repeatedly performed from the start to the end.

First, the voltage of the commercial power supply 1 is read (ST
EP 101). It is determined whether the read voltage of the commercial power supply 1 is within a range in which the precharge can be continued (STEP 10).
2) If it is out of the range, the pre-charge switch 8 is opened so that the pre-charge is not started (STEP 103). The range in which the pre-charging of the voltage of the commercial power supply 1 can be continued is a start condition of the high power factor converter 2, and is, for example, within ± 15% of the voltage of the commercial power supply 1.

If it is determined in STEP 102 that the pre-charge is within the continuation range, the pre-charge completion voltage is calculated (STEP 104). The calculation formula uses the commercial power supply voltage on the X axis,
The precharge completion voltage is obtained as an approximate expression from a graph arranged on the Y axis. FIG. 3 shows a graph as an example. From the figure, the calculation formula is as follows: Y = 1.2X if within the precharge continuation range, Y = 204 if outside the low voltage side range of the voltage of the commercial power supply 1, and Y = 204 outside the overvoltage side range of the voltage of the commercial power supply 1. Then, Y = 276. Next, the pre-charge voltage is read (STEP 1).
05), the precharge completion voltage calculated in STEP 104 is compared with the precharge voltage (STEP 106).

If the comparison result indicates that the pre-charge completion voltage has not been reached, the pre-charge switch 8 is turned on (STEP 107). If the pre-charge voltage has been reached, the process branches to STEP 103 and the pre-charge switch 8
To release. In the first embodiment, the pre-charge completion determination circuit is replaced with the pre-charge voltage determination / determination circuit 9, so that the pre-charge corresponding to the voltage of the commercial power supply 1 can be continued, and Damage to the rate converter 2 can be reduced, and a highly reliable device that can surely complete the pre-charge within a specified time can be obtained.

Embodiment 2 FIG. FIG. 4 is a block diagram showing a power converter according to Embodiment 2 of the present invention.
The difference from the first embodiment in the structure is that the precharge voltage determination / judgment circuit 9 receives the open command of the precharge switch 8 output after judging that the precharge is completed.
The difference is that a guidance circuit 10 for displaying the operation guidance of the completion of the preliminary charging is added, and the other configuration is the same as that of the first embodiment.

In the first embodiment, the procedure up to the opening of the pre-charging switch 8 when the pre-charging is completed in the pre-charging voltage determining / determining circuit 9 has been described. To do so, the operator had to check the voltage and other tasks. Therefore, in the present embodiment, as shown in FIG. 4, by providing the guidance circuit 10, it is possible to display the pre-charge completion state from the pre-charge voltage determination / determination circuit 9, so that the operator follows the guidance. , The operation can be shifted to the closing operation of the input switch 3, and the operability can be improved.

Embodiment 3 FIG. 5 is a block diagram showing a power converter according to Embodiment 3 of the present invention.
The difference from the first embodiment in the configuration is that the input switch 3 is constituted by an automatic circuit, and can be automatically turned on or opened without the operator operating the input switch 3. The precharge voltage determination / determination circuit 9 can output an automatic operation command of the input switch 3.

Next, the operation will be described. FIG. 6 is a flowchart showing the operation of the pre-charge voltage determination / judgment circuit 9, and the process is repeated from the start to the end. In the figure, it is determined whether the read voltage of the commercial power supply 1 is within a range in which the precharge can be continued (STEP 101, STEP 101).
2) If not, the input switch 3 and the pre-charge switch 8 are opened so that the high power factor converter 2 and the pre-charge circuit 7 are not activated (STEP 108).

In STEP 102, if it is within the range of the continuation of the pre-charge, the pre-charge completion voltage is calculated (STEP 102).
104), it is determined whether the preliminary charging is completed (STEP 105,
106). If the comparison result indicates that the precharge completion voltage has not been reached, the precharge switch 8 is turned on (STEP 107). If the pre-charge voltage has been reached, the input switch 3 is turned on (STEP 109), and the pre-charge switch 8 is opened (STEP 103). ST
In the switching operation of the input switch 3 and the pre-charge switch 8 in the EP 108 and the STEP 109, when the processing order is changed in order to protect the input circuit, or when a time difference is set between the processes, the input switch is switched from the pre-charge switch 8 opening to the input switch It is also possible to control the time until 3 inputs.

In the second embodiment, since the pre-charging is completed by the pre-charging voltage determination / judgment circuit 9, the procedure from when the pre-charging switch 8 is opened to when the operator operates the input switch 3 is performed. However, as shown in FIGS. 5 and 6, when the input switch 3 is an automatic circuit, the precharge completion state is determined by the precharge voltage determination / determination circuit 9.
Since the preliminary charging switch 8 is opened and the input switch 3 is turned on at the time when the operation is recognized, the operation can be easily performed by automation of the device, and a device excellent in operability can be obtained. it can.

Embodiment 4 FIG. 7 is a block diagram showing a power converter according to Embodiment 4 of the present invention.
The difference between the first embodiment and the first embodiment is that the precharge circuit 7 monitors that the precharge circuit 7 is operating normally, and if the precharge is not completed within a specified time, detects an abnormality. The difference is that a circuit 11 is added, and the other configuration is the same as that of the first embodiment. Further, the present invention can be similarly applied to the second and third embodiments.

Next, the operation will be described. FIG. 8 is a flowchart showing the operation of the pre-charging abnormality detection circuit 11, and the processing is repeatedly performed from the start to the end. In FIG. 8, it is monitored that the pre-charging is being performed by determining the ON state of the pre-charging switch 8 (STEP 11).
0). If the preliminary charging is being performed, the elapsed time is compared with a specified time and monitored (STEP 111). Here, the specified time is a time that can be calculated from the charging operation specification of the DC smoothing capacitor 4. In STEP 111, the fact that the pre-charge switch 8 has been turned on for more than the specified time indicates that the pre-charge completion voltage has not been reached within the specified time, and it is determined that the pre-charge is abnormal (STEP 1).
12).

FIG. 9 is a flowchart showing the operation of the pre-charge determination / judgment circuit 9. When the pre-charge circuit 7 is disconnected as a device protection interlocking operation after the detection of a pre-charge abnormality, the pre-charge in STEP 102 in FIG. An item of abnormal pre-charging is added to the continuable condition (STEP 11).
3). In the first embodiment, the case of the normal operation by switching the input circuit from the preliminary charging operation has been described. However, as shown in FIG. 7, a preliminary charging abnormality detection circuit 11 is provided to detect abnormality of the preliminary charging circuit 7. Since the input circuit can be opened as a protection interlocking operation, early detection of abnormality of the device and avoidance of double failure can be achieved, and a device having improved reliability and safety can be obtained.

Embodiment 5 FIG. FIG. 10 is a block diagram showing a power converter according to Embodiment 5 of the present invention. The difference from the fourth embodiment in the configuration is that the pre-charge abnormality detected by the pre-charge abnormality detection circuit 11, the pre-charge completion voltage determined by the pre-charge voltage determination / determination circuit 9 at the time of the detection, and the current An alarm output circuit 12 for displaying and outputting the pre-charge voltage is added, and the other configuration is the same as that of the fourth embodiment.

In the fourth embodiment, the abnormality of the pre-charging circuit 7 is detected by the pre-charging abnormality detecting circuit 11, and when the protection interlocking operation is performed, the operation is performed until the input switch 3 and the pre-charging switch 8 are opened. The operation has been described.
As shown in FIG. 0, an alarm output circuit 12 is provided to output a precharge abnormality and a current precharge voltage value and a precharge completion voltage value, thereby facilitating an abnormal state from a deviation from a target value. This makes it possible to improve the efficiency of maintenance work such as narrowing down a failure location.

[0029]

According to the power converter according to the first aspect of the present invention, a pre-charging circuit is provided on the output side of the commercial power supply, and the converter is started after pre-charging to a certain voltage, Since the precharge completion voltage is determined from the value of the commercial power supply, and the voltage of the commercial power supply is determined to be within the range where the precharge is continued, a precharge voltage determination / determination circuit for issuing a precharge start command is provided. , It is possible to continue the preliminary charging corresponding to the voltage of the commercial power supply,
It is possible to obtain a highly reliable device which can reduce the damage to the converter and can surely complete the pre-charge within a specified time.

According to the power converter according to the second aspect of the present invention, since the guidance circuit for displaying the operation guidance of the completion of the pre-charging is provided, the operator can shift to the operation of turning on the input switch according to the guidance. Performance can be improved.

According to the power converter according to claim 3 of the present invention, the precharge voltage determination / judgment circuit outputs an automatic operation command for activating the converter.
Operation can be performed easily.

According to the power converter of the fourth aspect of the present invention, since the precharge abnormality detecting circuit for detecting whether the precharge is completed within the specified time is provided, the abnormality of the device can be detected early. It is possible, and a double failure can be avoided. .

According to the power converter according to claim 5 of the present invention, the alarm output circuit for displaying and outputting the precharge abnormality and the current precharge voltage value and the precharge completion voltage value is provided. An abnormal state can be easily recognized from the deviation from the target value, and the efficiency of maintenance work such as narrowing down a failure location can be improved.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a power converter according to Embodiment 1 of the present invention.

FIG. 2 is a flowchart showing the operation of the first embodiment of the present invention.

FIG. 3 is a graph referred to in an arithmetic operation according to the first embodiment of the present invention.

FIG. 4 is a block diagram showing a power converter according to a second embodiment of the present invention.

FIG. 5 is a block diagram showing a power converter according to a third embodiment of the present invention.

FIG. 6 is a flowchart showing the operation of the third embodiment of the present invention.

FIG. 7 is a block diagram showing a power converter according to a fourth embodiment of the present invention.

FIG. 8 is a flowchart showing an operation of the fourth embodiment of the present invention.

FIG. 9 is a flowchart showing the operation of the fourth embodiment of the present invention.

FIG. 10 is a block diagram showing a power converter according to a fifth embodiment of the present invention.

FIG. 11 is a block diagram showing a conventional power converter.

FIG. 12 is a flowchart illustrating the operation of a conventional power converter.

[Explanation of symbols]

1 commercial power supply, 2 converter, 7 pre-charge circuit, 9
Precharge voltage determination / judgment circuit, 10 guidance circuit, 11 precharge abnormality detection circuit, 12 alarm output circuit.

Claims (5)

[Claims] 1. A power converter for providing a pre-charging circuit on the output side of a commercial power supply, starting a converter after pre-charging to a certain voltage, and determining a pre-charging completion voltage from the value of the commercial power. Judging that the voltage of the commercial power supply is within the range for continuing the pre-charging,
A power conversion device comprising a precharge voltage determination / judgment circuit for issuing a precharge start command. 2. A power conversion device comprising a guidance circuit for displaying an operation guidance of completion of pre-charging. 3. The power converter according to claim 1, wherein the precharge voltage determination / judgment circuit outputs an automatic operation command for starting the converter. 4. The electric power according to claim 1, further comprising a pre-charging abnormality detection circuit for detecting whether the pre-charging is completed within a prescribed time. Conversion device. 5. The power converter according to claim 4, further comprising an alarm output circuit for displaying and outputting a precharge abnormality and a current precharge voltage value and a precharge completion voltage value.