JP3625181B2 - Power converter - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a power conversion device including a high power factor converter including a precharge circuit, and more particularly to a device that is activated by switching a precharge completion voltage by determining the state of an input voltage.
[0002]
[Prior art]
FIG. 11 is a block diagram showing a conventional power converter provided with a high power factor converter described in, for example, Japanese Patent Laid-Open No. 59-61475. In the figure, 2l is a commercial power source, and 22 is a commercial power source 2l. A high power factor converter that converts alternating current power that is output into direct current power, 23 is an input switch for connecting the commercial power source 21 and the high power factor converter 22, and 24 is for controlling the current with the high power factor converter 22. DC smoothing capacitor in which a DC voltage is stored, 25 is an inverter that converts DC power output from the high power factor converter 22 into AC power, 26 is a load that receives the output of the inverter 25, and 27 is a high power factor converter 22. A precharge circuit 28 for charging a DC voltage to the DC smoothing capacitor 24 in advance before start-up, and 28 a sufficient voltage for the precharge circuit 27 are charged. Precharging completion determination circuit determines that could, 29 the AC power outputted from the commercial power supply 2l, a pre-charge switch to connect to the pre-charging circuit 27.
[0003]
FIG. 12 is a flowchart showing the operation of the precharge completion determination circuit 28. The process shown in FIG. 12 is repeated from the start to the end. By turning on the preliminary charging switch 29, the preliminary charging voltage is read in order to input the AC power from the commercial power source 21 to the preliminary charging circuit 27 (STEP 201). It is determined whether the precharge voltage has reached the precharge completion voltage (STEP 202). If not, the precharge switch 29 is turned on (STEP 203). The precharge completion voltage here is a voltage calculated from the accumulated voltage capacity of the DC smoothing capacitor 24 as a determination value.
[0004]
In the preliminary charging circuit 27, AC power is converted into DC power, and preliminary charging to the DC smoothing capacitor 24 is started. If it is determined in STEP 202 that the preliminary charging is completed, the preliminary charging switch 29 is opened (STEP 204). The operator recognizes the completion of the preliminary charging and turns on the input switch 23 to activate the high power factor converter 22. The high power factor converter 22 operates by controlling the current supplied from the commercial power supply 21 with the DC voltage charged in the DC smoothing capacitor 24. Next, by starting the inverter 25, AC power converted from DC power is supplied to the load 26.
[0005]
[Problems to be solved by the invention]
Since the conventional power converter is configured as described above, the preliminary charging is completed at a constant voltage. Therefore, when the voltage of the commercial power source is high, the preliminary charging is completed relatively quickly, while the high power factor. When the input circuit is switched to the converter, the damage to the high power factor converter circuit is significant, and pre-charging with a low commercial power supply voltage requires more time for pre-charging or pre-charging completion voltage. There was a problem such as not reaching.
[0006]
The present invention has been made to solve the above-described problems, and is affected by the voltage state of the commercial power supply by determining the measured value of the commercial power supply voltage and changing the precharge completion voltage. It aims at obtaining the power converter device which can continue a preliminary charge, without.
[0007]
[Means for Solving the Problems]
According to a first aspect of the present invention, a power converter is provided with a precharge circuit on the output side of a commercial power supply, and starts a converter after performing a precharge to a certain voltage. In addition to determining the completion voltage, a precharge voltage determination / determination circuit is provided that determines that the voltage of the commercial power source is within a range in which precharge is continued and issues a precharge start command.
[0008]
The power conversion device according to claim 2 of the present invention is provided with a guidance circuit for displaying operation guidance for completion of preliminary charging.
[0009]
According to a third aspect of the present invention, the precharge voltage determination / determination circuit outputs an automatic operation command for starting the converter.
[0010]
According to a fourth aspect of the present invention, there is provided a precharge abnormality detection circuit that detects whether or not precharge is completed within a specified time.
[0011]
The power conversion device according to claim 5 of the present invention is provided with an alarm output circuit for displaying and outputting the current precharge voltage value and the precharge completion voltage value, indicating that the precharge abnormality has occurred.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
Embodiment 1 FIG.
Hereinafter, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram showing a power conversion apparatus according to Embodiment 1 of the present invention. In the figure, l is a commercial power source, and 2 is a high power that converts AC power output from the commercial power source 1 into DC power. A rate converter, 3 is an input switch for connecting the commercial power source 1 and the high power factor converter 2, 4 is a DC smoothing capacitor in which a DC voltage is stored for controlling the current by the high power factor converter 2, An inverter that converts the DC power output from the high power factor converter 2 into AC power, 6 is a load that receives the output of the inverter 5, and 7 is a DC voltage previously applied to the DC smoothing capacitor 4 before the high power factor converter 2 is started. Is a preliminary charging circuit for charging the battery.
[0013]
8 is a precharge switch for connecting the AC power output from the commercial power source 1 to the precharge circuit 7, and 9 is a preliminary charge completion voltage determined from the voltage value of the commercial power source 1. Comparing the charge completion voltage with the precharge voltage, or determining that the voltage of the commercial power source 1 is within the range for continuing the precharge, and determining the precharge voltage to issue a command to turn on or open the precharge switch 8 It is a determination circuit.
[0014]
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 9 , and the other configuration performs the same operation.
FIG. 2 is a flowchart showing the operation of the precharge voltage determination / determination circuit 9. The process shown in FIG. 2 is repeated from the start to the end.
[0015]
First, the voltage of the commercial power source 1 is read (STEP 101). It is determined whether or not the read voltage of the commercial power supply 1 is within a range where the preliminary charging can be continued (STEP 102). If the voltage is out of the range, the preliminary charging switch 8 is opened so as not to start the preliminary charging (STEP 103). The range in which the precharge of the voltage of the commercial power source 1 can be continued here is a start condition of the high power factor converter 2, for example, within ± 15% of the voltage of the commercial power source 1.
[0016]
If it is determined in STEP102 that the preliminary charging is within the range of continuing the preliminary charging, the preliminary charging completion voltage is calculated (STEP104). The calculation formula is obtained as an approximate formula from a graph in which the commercial power supply voltage is arranged on the X axis and the precharge completion voltage is arranged on the Y axis.
FIG. 3 shows a graph as an example. If the calculation formula is within the precharge continuation range from the figure,
Y = 1.2X
If the voltage of the commercial power supply 1 is outside the low voltage range,
Y = 204
If it is outside the overvoltage side range of the voltage of the commercial power supply 1,
Y = 276
It becomes. Next, the preliminary charging voltage is read (STEP 105), and the preliminary charging completion voltage calculated in STEP 104 is compared with the preliminary charging voltage (STEP 106).
[0017]
If the comparison result shows that the precharge completion voltage has not been reached, the precharge switch 8 is turned on (STEP 107). If the precharge voltage has been reached, the process branches to STEP 103 and the precharge switch 8 is opened.
In the first embodiment, since the preliminary charging completion determination circuit is replaced with the preliminary charging voltage determination / determination circuit 9, the preliminary charging corresponding to the voltage of the commercial power source 1 can be continued. Damage to the rate converter 2 can be reduced, and a highly reliable device that can reliably complete the preliminary charging within a specified time can be obtained.
[0018]
Embodiment 2. FIG.
4 is a block diagram showing a power conversion apparatus according to Embodiment 2 of the present invention.
The difference from the first embodiment in the configuration is that the preliminary charging voltage determination / determination circuit 9 receives the opening instruction of the preliminary charging switch 8 that is output after the preliminary charging is determined to be completed, and performs the preliminary charging completion operation. The point is that a guidance circuit 10 for displaying guidance is added, and other configurations are the same as those in the first embodiment.
[0019]
In the first embodiment, the procedure until the preliminary charging switch 8 is opened after the preliminary charging is completed in the preliminary charging voltage determination / determination circuit 9 has been described. To turn on the input switch 3 The operator needed to check the voltage value. Therefore, in the present embodiment, as shown in FIG. 4, by providing the guidance circuit 10, it is possible to display the precharge completion state from the precharge voltage determination / determination circuit 9, so that the operator follows the guidance. Therefore, the operation can be shifted to the input operation of the input switch 3, and the operability can be improved.
[0020]
Embodiment 3 FIG.
5 is a block diagram showing a power conversion apparatus according to Embodiment 3 of the present invention. The difference from the first embodiment in the configuration is that the input switch 3 is configured 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 for the input switch 3.
[0021]
Next, the operation will be described.
FIG. 6 is a flowchart showing the operation of the precharge voltage determination / determination circuit 9, and the process is repeated from the start to the end.
In the figure, it is determined whether or not the read voltage of the commercial power supply 1 is within a range in which the preliminary charging can be continued (STEP 101, 102). If the voltage is out of the range, the high power factor converter 2 and the preliminary charging circuit 7 are not activated. Then, the input switch 3 and the precharge switch 8 are opened (STEP 108).
[0022]
In STEP102, if it is within the range of continuation of preliminary charging, the preliminary charging completion voltage is calculated (STEP 104), and the completion of preliminary charging is determined (STEP 105, 106). If the comparison result shows that the precharge completion voltage has not been reached, the precharge switch 8 is turned on (STEP 107). If the precharge voltage has been reached, the input switch 3 is turned on (STEP 109), and the precharge switch 8 is opened (STEP 103). In the switching operation of the input switch 3 and the preliminary charging switch 8 in STEP 108 and STEP 109, when the processing order is changed in order to protect the input circuit, or when a time difference is set between the processing, the preliminary charging switch 8 is opened to the input switch. It is also possible to control the time until 3 is input.
[0023]
In the second embodiment, the procedure from the completion of the preliminary charging by the preliminary charging voltage determination / determination circuit 9 to the opening of the preliminary charging switch 8 until the operator operates the input switch 3 has been described. However, as shown in FIGS. 5 and 6, when the input switch 3 is an automatic circuit, when the preliminary charging completion state is recognized by the preliminary charging voltage determination / determination circuit 9, the preliminary charging switch 8 is opened, Since the input switch 3 is turned on, the operation can be easily performed by automating the apparatus, and an apparatus with excellent operability can be obtained.
[0024]
Embodiment 4 FIG.
FIG. 7 is a block configuration diagram showing a power conversion device according to Embodiment 4 of the present invention. The difference from the first embodiment in the configuration is that the precharging circuit 7 is monitored to operate normally, and if the precharging is not completed within the specified time, the precharging abnormality detection is performed to detect an abnormality. The circuit 11 is added, and other configurations are the same as those in the first embodiment. The present invention can be similarly applied to the second to third embodiments.
[0025]
Next, the operation will be described.
FIG. 8 is a flowchart showing the operation of the precharge abnormality detection circuit 11, and the process is repeated from the start to the end.
In FIG. 8, it is monitored that preliminary charging is being performed by determining whether the preliminary charging switch 8 is turned on (STEP 110). If pre-charging is in progress, the elapsed time is compared with the specified time and monitored (STEP 111). Here, the specified time is a time that can be calculated from the charging operation specifications of the DC smoothing capacitor 4. In STEP 111, the fact that the precharge switch 8 has been turned on beyond the specified time indicates that the precharge completion voltage could not be reached within the specified time, and it is determined that the precharge is abnormal (STEP 112).
[0026]
FIG. 9 is a flowchart showing the operation of the preliminary charging determination / determination circuit 9. When the preliminary charging circuit 7 is disconnected as the device protection interlocking operation after the preliminary charging abnormality is detected, the preliminary charging continuation condition of STEP 102 in FIG. In addition, an item of abnormal precharging is added (STEP 113).
In the first embodiment, the case of normal operation by switching the input circuit from the precharge operation has been described. However, as shown in FIG. 7, the precharge abnormality detection circuit 11 is provided to detect abnormality of the precharge circuit 7. Since the input circuit can be opened as the protection interlocking operation, it is possible to detect the abnormality of the apparatus early and avoid the double failure, and it is possible to obtain the apparatus with improved reliability and safety performance.
[0027]
Embodiment 5. FIG.
10 is a block diagram showing a power conversion apparatus according to Embodiment 5 of the present invention. The difference from the fourth embodiment in the configuration is that the preliminary charging abnormality detected by the preliminary charging abnormality detection circuit 11, the preliminary charging completion voltage determined by the preliminary charging voltage determination / determination circuit 9 at the time of detection, and the present The alarm output circuit 12 that displays and outputs the precharge voltage is added, and the other configuration is the same as that of the fourth embodiment.
[0028]
In Embodiment 4 described above, the operation until the precharge abnormality detection circuit 11 detects an abnormality in the precharge circuit 7 and performs the protection interlock operation until the input switch 3 and the precharge switch 8 are opened is described. However, as shown in FIG. 10, an alarm output circuit 12 is provided, which indicates that there is an abnormality from the deviation from the target value by outputting the current preliminary charging voltage value and the preliminary charging completion voltage value because of abnormal charging. Status can be easily recognized, and the efficiency of maintenance work such as narrowing down of failure points can be improved.
[0029]
【The invention's effect】
According to the power conversion device of the first aspect of the present invention, the preliminary charging circuit is provided on the output side of the commercial power source, and the converter is started after the preliminary charging is performed up to a certain voltage. Since the precharge completion voltage is determined, it is determined that the commercial power supply voltage is within the range for continuing the precharge, and a precharge voltage determination / determination circuit for issuing a precharge start command is provided. Thus, it is possible to continue the preliminary charging corresponding to the above, reduce the damage received by the converter, and obtain a highly reliable device that can reliably complete the preliminary charging within a specified time.
[0030]
According to the power conversion device of the second aspect of the present invention, since the guidance circuit for displaying the operation guidance for the completion of the preliminary charging is provided, the operator can shift to the input switch turning-on operation according to the guidance, thereby improving the operability. Can be made.
[0031]
According to the power conversion device of the third aspect of the present invention, since the precharge voltage determination / determination circuit outputs the automatic operation command for starting the converter, the operation can be easily performed.
[0032]
According to the power conversion device according to claim 4 of the present invention, since the precharge abnormality detection circuit for detecting whether or not the precharge is completed within the specified time, it is possible to detect the abnormality early of the device, In addition, double failure can be avoided. .
[0033]
According to the power conversion device according to claim 5 of the present invention, since the precharge abnormality is present and the alarm output circuit for displaying and outputting the current precharge voltage value and the precharge completion voltage value is provided, the target value and From this deviation, it is possible to easily recognize the abnormal state, and to improve the efficiency of the maintenance work such as narrowing down the failure location.
[Brief description of the drawings]
FIG. 1 is a block diagram showing a power conversion apparatus 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 a calculation operation in the first embodiment of the present invention.
FIG. 4 is a block configuration diagram showing a power conversion device according to a second embodiment of the present invention.
FIG. 5 is a block configuration diagram showing a power conversion device according to Embodiment 3 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 configuration diagram showing a power conversion device according to Embodiment 4 of the present invention.
FIG. 8 is a flowchart showing the 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 configuration diagram showing a power conversion device according to Embodiment 5 of the present invention;
FIG. 11 is a block diagram showing a conventional power converter.
FIG. 12 is a flowchart showing the operation of a conventional power converter.
[Explanation of symbols]
1 commercial power supply, 2 converter, 7 precharge circuit,
9 Precharge voltage determination / determination circuit, 10 guidance circuit,
11 Precharge abnormality detection circuit, 12 alarm output circuit.

Claims (5)

In the power conversion device that provides a precharge circuit on the output side of the commercial power supply and starts the converter after performing precharge to a certain voltage, the precharge completion voltage is determined from the value of the commercial power supply, and the voltage of the commercial power supply Is provided with a precharge voltage determination / determination circuit that determines that the precharge is within a range for continuing precharge and issues a precharge start command. The power conversion device according to claim 1, further comprising a guidance circuit that displays an operation guidance for completion of preliminary charging. 2. The power converter according to claim 1, wherein the precharge voltage determination / determination circuit outputs an automatic operation command for starting the converter. The power converter according to any one of claims 1 to 3, further comprising a precharge abnormality detection circuit that detects whether or not precharge is completed within a specified time. 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.

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