JP4607018B2 - Inverter device for motor drive - Google Patents

Description

  The present invention relates to an inverter device for driving a motor that generates AC power of variable voltage and variable frequency, and drives the motor, in particular, an electric motor used for driving a fan, a pump, etc., at a variable speed by using the AC power.

  FIG. 6 is a circuit configuration diagram showing a conventional example of this type of inverter device. In this figure, 1 is an AC power source such as a commercial power source, 2 is an inverter device for driving a motor, and 3 is an electric motor such as an induction motor driven at a variable speed by an inverter device 2 for driving a motor.

The inverter device 2 for driving the electric motor has a constant voltage and a constant frequency commercial power of the AC power supply 1 while maintaining a ratio (V / f) between the output voltage V and the frequency f to be substantially constant. It is composed of a general-purpose inverter 21 that is generally used for converting to AC power, electromagnetic contactors 22 and 23 that constitute a changeover switch, and a sequence control circuit 24. The electromagnetic contactors 22 and 23 are controlled to be opened and closed so as to switch and connect the electric motor 3 to the output of the AC power source 1 and the output of the general-purpose inverter 21.
When the general-purpose inverter 21 is normally operated, the operation signals S22 and S23 for turning on the contact of the electromagnetic contactor 22 and turning off the contact of the electromagnetic contactor 23 are sent from the sequence control circuit 24, respectively. 23. As a result, AC power having a desired voltage and frequency output from the general-purpose inverter 21 is supplied to the electric motor 3, and a pump or a fan (not shown) as a load of the electric motor 3 is driven.

  In such an inverter device, when any malfunction occurs in the operating general-purpose inverter 21, the general-purpose inverter 21 stops generating AC power and sends a failure signal E to the sequence control circuit 24. Based on the failure signal E, the sequence control circuit 24 switches the operation signals S22 and S23 to be applied to the electromagnetic contactors 22 and 23 so that the electromagnetic contactor 22 is turned off and the electromagnetic contactor 23 is turned on. As a result, the electric motor 3 is supplied with electric power directly from the AC power source 1 and continues to operate.

  However, in such a conventional motor drive device, since the rotation speed of the motor 3 is different between the state in which the motor 3 is driven by the general-purpose inverter 21 and the state in which the motor 3 is directly driven by the AC power source 1, for example, When the load of the electric motor 3 is a pump, a fan, etc., there has been a problem that the ability changes.

As a solution to such a problem, for example, Patent Document 1 below discloses a method of alternately operating two water supply systems using two inverters, an induction motor, and a pump.
JP-A-61-38182 (pages 3-4, FIG. 1)

  In the conventional motor drive inverter device 2 shown in FIG. 6, since only one set of general-purpose inverters 21 is provided, this inverter has some trouble, and the electric power of the AC power source 1 is supplied to the motor 3. In this state, as described above, the operation state of the fan or pump of the motor load may change. In addition, when a malfunction occurs in the general-purpose inverter 21 after normal operation of the general-purpose inverter 21 for a long period (for example, several years or more), when switching to power supply from the AC power source 1, the electromagnetic contactor 22, There is also a possibility that switching from the AC power source 1 to power feeding may become impossible due to malfunction due to welding of the 23 contacts.

  In addition, as disclosed in Patent Document 1 above, a configuration in which two sets of inverters, induction motors, and pumps are operated alternately for one water supply system requires a larger installation space, and There was a problem that the entire apparatus was expensive.

  An object of the present invention is to provide an inverter device for driving a motor that can solve the above-mentioned problems.

In order to solve the above-mentioned problem, this first invention generates AC power of variable voltage and variable frequency, and the inverter device is configured in an inverter device for driving a motor that drives the motor at a variable speed by the generated AC power. Among each component, at least two sets of inverter main circuit components for generating AC power are provided, and during normal operation time of one set of inverter main circuit components from the start command. when stop command stops the preset within the set time is given, along with providing an instruction for switching the operation to the other set of inverter main circuit unit waiting when subsequently a new start command is given to, when the stop command to the one set of the inverter main circuit unit in operation within the set time is not given, it is waiting after a pre-Symbol set time Driving square set of the two sets of the inverter main circuit unit by providing a directive to switch the operation to the inverter main circuit unit alternately is defective one set of inverter main circuit unit in this operation When detected, the operation of one set of inverter main circuit components during operation is stopped and the other set of inverter main circuit components during standby is given a command to switch operation to the other set of standby main circuits. The inverter main circuit constituent part is provided with alternate operation control means for switching operation .

  According to a second invention, in the inverter device of the first invention, the two sets of inverter main circuit components are mounted on an integrated heat sink.

Further, the third invention is the inverter device of the second invention, wherein two sets of fans for cooling the heat sink are provided, and in normal times, each set of fans is operated alternately one by one. When a failure is detected in the fan, the operation is switched to the other set of fans.

  According to this invention, two sets of inverter main circuit components constituting the AC power converter in the motor drive inverter device are provided, and the inverter main circuit components of each set are alternately switched to operate. One set of inverter main circuit components can fail and the other set of inverter main circuit components can continue the operation of the motor without changing the conditions. Therefore, the operational reliability of the entire apparatus including the load device of the motor Is improved. In this case, since only one set of loads such as the electric motor and the pumps and fans driven by the electric motor is provided, the entire apparatus can be reduced in size and cost. In addition, while operating one set of inverter main circuit components in the inverter device, maintenance and inspection work can be performed on the other set of inverter main circuit components that are stopped. In addition, by operating the inverter main circuit components of each set alternately, the operating time of both inverter main circuit components can be made substantially equal, so that a malfunction occurred in the operating inverter main circuit components. Sometimes, if the cause is due to deterioration of aging, it can be known that the other healthy inverter main circuit component has come to be replaced, and preventive maintenance can be achieved.

Embodiments of the present invention shown in the drawings will be described below.
FIG. 1 is a circuit configuration diagram showing a first embodiment of an inverter device for driving a motor according to the present invention. Components having the same functions as those of the conventional example shown in FIG. Yes.

  That is, the motor drive inverter device 4 shown in FIG. 1 has two sets of inverters that are completely unitized such as general-purpose inverters so that AC power of variable voltage and variable frequency can be generated independently of each other. Units 41 and 42, two sets of electromagnetic contactors 43 and 44, and one set of alternating operation control circuit 45 are provided. The magnetic contactors 43 and 44 are switched on when the side connected to one of the operating inverter units is turned on, and when the side connected to the stopped inverter unit is turned off, the connection between the motor 3 and the inverter units 41 and 41 is switched. In addition, the output of one operating inverter unit is prevented from entering the other stopped inverter unit, and the stopped inverter unit is disconnected from the main circuit for safer maintenance and inspection. Has been installed for.

Further, the alternate operation control circuit 45 sends on / off signals P41 and P42 for individually operating or stopping the inverter unit 41 and the inverter unit 42 based on the operation of the start switch 45a and the stop switch 45b. The control operation shown in the flowchart of FIG. 2 is performed. Further, the alternating operation control circuit 45 sends a common setting signal D for generating an AC voltage having a desired voltage and frequency to the inverter units 41 and 42 as the motor driving inverter device 4.
Further, the alternate operation control circuit 45 receives the failure signal E41 from the inverter unit 41, turns on the corresponding failure display lamp 45c, and sounds the common alarm buzzer 45e, and sends the failure signal E42 from the inverter unit 42. The common alarm buzzer 45e is sounded while the failure display lamp 45d corresponding to this is turned on by receiving. In addition, based on a failure signal E41 from the operating inverter unit 41, an on / off signal P42 for starting this is sent to the stopped inverter unit 42, and then the electromagnetic contactor 43 is turned off and the electromagnetic contactor 44 is turned on. The operation signals S43 and S44 to be transmitted are sent out. In addition, an on / off signal P41 for starting the inverter unit 41 is sent based on the failure signal E42 from the operating inverter unit 42, and thereafter, the operation signal S44 for turning off the electromagnetic contactor 44 and turning on the electromagnetic contactor 43. , S43 and other sequence control operations are performed.

  FIG. 2 is a flowchart for explaining a normal control operation of the alternate operation control circuit 45 based on the operation of the start switch 45a and the stop switch 45b.

  First, as an initial state, the inverter unit 41 and the inverter unit 42 are stopped, the electromagnetic contactors 43 and 44 are turned off, a timer to be described later is set to “0”, the start switch 45a is pressed, and the start command (Step S1, branch N). Here, when the start switch 45a is pressed and a start command is applied, branch Y is selected in step S1, and the process proceeds to step S2, where an on / off signal P41 to the inverter unit 41 is sent as "ON", thereby sending the inverter unit 41. Starts operation, generates an AC power having a voltage and frequency based on the setting signal D, gives an ON operation signal S43 to the electromagnetic contactor 43, turns it ON, and supplies power to the motor 3 from the inverter unit 41. And the process proceeds to step S3. In step S3, a timer for counting the operation time of the inverter unit built in the alternating operation control circuit 45 is started, and the operation time of the inverter unit 41 is started by this timer.

Next, in step S4, the stop switch 45b is pressed to wait for a stop command to be applied. If not yet pressed, the process proceeds from branch N of step S4 to step S5, where the count value of the timer is It is checked whether or not a preset time, for example, 24 hours or longer, and if it is less than the set value of 24 hours, the process returns from the branch N of step S5 to step S4.
If the stop switch 45b is pressed and a stop command is given, branch Y is selected in step S4, and the process proceeds to step S6. In step 6, in order to stop the inverter unit 41, an on / off signal P41 to the inverter unit 41 is sent as “off”, thereby stopping the operation of the inverter unit 41 and turning off the electromagnetic contactor 43. Then, the count of the timer is stopped, and the count value is returned to “0”.

  In the next step S8, the start switch 45a is pressed again to wait for the start command to be added (step S8, branch N). When the start switch 45a is pressed and the start command is applied, the process starts from branch Y in step S8. The process proceeds to step S9. In step S9, an ON / OFF signal P42 to the inverter unit 42 is sent as “ON” to start the operation of the inverter unit 42 and generate AC power having a voltage and frequency based on the setting signal D, while An operation signal S44 to be turned on is given to the contactor 44, this is turned on, power supply from the inverter unit 42 to the electric motor 3 is started, the process proceeds to step S10, the timer is started again, and the operation time of the inverter unit 42 is started by this timer. Start counting.

  Next, in step S11, the stop switch 45b is pressed to wait for a stop command to be applied. If not yet pressed, the process proceeds from branch N of step S11 to step S12, and the count value of the timer is set to the set value. If it is less than 24 hours, the process returns from step N of step S12 to step S11. Further, when the stop switch 45b is pushed and a stop command is applied, the process proceeds from the branch Y in step S11 to step S13, and sends an ON / OFF signal P42 to the inverter unit 42 as “OFF”, so that the inverter unit 42 The operation is stopped and an operation signal S44 to be turned off is given to the electromagnetic contactor 44, which is turned off, and the process proceeds to step S14. In step S14, the timer is stopped again, the count value is set to “0”, and the process returns to step S1.

  On the other hand, in step S5, when the count value of the timer becomes equal to or more than the set value of 24 hours, the process proceeds from branch Y in step S5 to step S15 and sends the on / off signal P41 to the inverter unit 41 as “OFF”. Thus, the operation of the inverter unit 41 is stopped, the operation signal S43 to the electromagnetic contactor 43 is turned off, this is turned off, and the process proceeds to step S16. In step S16, the timer is stopped, the count value is set to “0”, and the process proceeds to step S9.

  In step S12, when the count value of the timer becomes equal to or greater than the set value of 24 hours, the process proceeds from branch Y in step S12 to step S17, and the on / off signal P42 to the inverter unit 42 is transmitted as "OFF". Thus, the operation of the inverter unit 42 is stopped, the operation signal S44 to the electromagnetic contactor 44 is turned off to turn it off, and the process proceeds to step S18. In step S18, the timer is stopped, the count value is set to “0”, and then the process proceeds to step S2.

  In this way, by controlling the inverter device 4 for driving the motor as shown in the flowchart of FIG. 2 by the alternating operation control circuit 45, the start switch 45a and the stop switch 45b are set to a preset time, for example, 24. By alternately pushing within the time, the inverter unit 41 and the inverter unit 42 are operated alternately, and once the start switch 45a is pushed, no operation is performed automatically. Therefore, the inverter unit 41 and the inverter unit 42 are alternately operated every 24 hours set. As a result, the electromagnetic contactors 43 and 44 are also operated alternately in a relatively short time, and the operation reliability can be improved.

On the other hand, when a malfunction occurs in the inverter unit 41 or the inverter unit 42 in operation, the failure signal E41 or E42 is given to the alternate operation control circuit 45 as an interrupt signal, respectively. When the alternate operation control circuit 45 receives such a failure signal E41 or E42, the alternate operation control circuit 45 automatically switches the operation to the healthy inverter unit 42 or the inverter unit 41 as shown in FIG. The electromagnetic contactors 43 and 44 are switched on and off to continue power supply to the motor 3.
In addition, when a malfunction occurs in the inverter unit 41 or the inverter unit 42 in operation, the corresponding failure display lamp 45c or 45d is turned on by the failure signal E41 or E42, and the alarm buzzer 45e is sounded. Therefore, once the operation of the inverter is stopped automatically or manually, the power supply to the motor 3 is stopped, the occurrence of the failure is confirmed, and the start switch 45a is newly pressed, It is possible to start the operation of the other healthy standby inverter unit 42 or the inverter unit 41 and restart the power supply from the inverter that has started this operation.

  FIG. 4 is a circuit diagram showing a second embodiment of the inverter device for driving an electric motor according to the present invention. Components having the same functions as those in the conventional example shown in FIG. Yes.

  The motor drive inverter device 5 in FIG. 4 includes two sets of inverter main circuit components 51 and 52 constituting an AC power conversion unit formed from a diode rectifier circuit, an electrolytic capacitor, an inverter circuit, and the like, and the inverter main circuit. Two sets of inverter main circuit components 51 and 52 that perform control for generating AC power of variable voltage and variable frequency from the component 51 or the inverter main circuit component 52, and a pair of inverter control circuits 53 and 2 A set of electromagnetic contactors 54, 55, a set of alternating operation control circuits 56, a set of heat sinks 57 that dissipate heat generated from the inverter main circuit component 51 or the inverter main circuit component 52, and the heat sink 57 are cooled. Two sets of fans 57a and 57b and a set of temperature sensors 58 for detecting the temperature of the heat sink 57. It is. The electromagnetic contactors 54 and 55 switch the connection to the output of the inverter main circuit components 51 and 52 of the electric motor 3, and the other one in which the output of the one inverter main circuit component 51 or 52 in operation is stopped. Is prevented from entering the inverter main circuit constituting section 52 or 51. Further, the inverter main circuit component 51 or the inverter main circuit component 52 that is stopped is installed to be separated from the operation circuit to perform maintenance and inspection work more safely.

The alternate operation control circuit 56 is configured to individually operate or stop the inverter main circuit configuration unit 51 and the inverter main circuit configuration unit 52 via the inverter control circuit 53 based on the operation of the start switch 56a and the stop switch 56b. In order to send the switching signal C, the control operation similar to the flowchart shown in FIG. The inverter control circuit 53 selectively gives a control signal in accordance with the setting signal D to the inverter main circuit component 51 or 52 based on the switching signal C given from the alternate operation control circuit 56, and two sets of inverter main circuits It acts on the components in common.
Further, the alternating operation control circuit 56 generates AC power having a desired voltage and frequency to the inverter main circuit component 51 and the inverter main circuit component 52 via the inverter control circuit 53. A setting signal D for transmitting the data is transmitted. Further, the alternating operation control circuit 56 takes in the output voltage of the inverter main circuit component 51 or 52 supplied to the electric motor 3 via the contacts of the electromagnetic contactors 54 and 55, and the inverter main circuit in operation from the voltage state. The failure of the circuit component is detected, and when detected, the alarm buzzer 56e is sounded while the failure display lamp 56c or 56d corresponding to the inverter main circuit component being operated is turned on to notify the occurrence of the failure.
Furthermore, when it is detected that a failure has occurred in the inverter main circuit component 51 during operation, a switching signal C for operating the inverter main circuit component 52 is sent to the inverter control circuit 53 based on this. Thereafter, operation signals S54 and S55 for turning off the electromagnetic contactor 54 and turning on the electromagnetic contactor 55 are sent out. When the occurrence of a failure is detected during operation of the inverter main circuit component 52, a switching signal C for operating the inverter main circuit component 51 is sent to the inverter control circuit 53 based on this, Thereafter, a series of sequence control operations such as sending the operation signals S55 and S54 for turning off the electromagnetic contactor 55 and turning on the electromagnetic contactor 54 are performed.
Therefore, the inverter main circuit components 51 and 52 in this embodiment are alternately switched in the same manner as the inverter units 41 and 42 in the above-described embodiment, and thus detailed description of the operation is omitted.

FIG. 5 is a schematic conceptual diagram of the heat sink 57, the fan 57a, and the fan 57b shown in FIG. 4. In this figure, two sets of inverter main circuit components 51 and an inverter main circuit are provided on a common heat sink 57. The component 52 is mounted, and the two sets of fans 57a and 57b and the illustrated cooling fins 57c constitute the inverter main circuit component 51 or the inverter main circuit component 52 cooling device.
Heat generated during operation of the two sets of inverter main circuit components 51 and 52 is transmitted to the heat sink 57, and this heat is radiated from the cooling fins 57c cooled by the cooling air sent from the cooling fans 57a and 57b. Is done. At this time, in the alternate operation control circuit 56, normally, the fan 57a is rotated and the fan 57b is stopped while the inverter main circuit component 51 is operating, while the inverter main circuit component 52 is operating. The fan 57b is rotated and the fan 57a is stopped. However, when the inverter main circuit component 51 is determined to be outputting AC power normally and the temperature of the heat sink 57 detected by the temperature sensor 58 exceeds a predetermined upper limit value, the fan 57a has failed. The failure indicator lamp 56c and the buzzer 56e are operated, and the sound fan 57b is operated.

  That is, in the inverter main circuit configuration unit 51 and the inverter main circuit configuration unit 52 shown in FIG. 4, among the components of the inverter main circuit configuration unit, an electrolytic capacitor having a relatively short lifetime of about several years due to aging deterioration, Two sets of inverter main circuit components including main circuit elements that are subject to great damage such as power semiconductor elements that may be damaged by instantaneous overvoltage, overcurrent or noise, and these two sets of inverter main circuit components Are provided in common, and two sets of fans 57a and 57b for cooling the heat sink 57 shown in FIG. 5 are provided, and by operating these inverter main circuit components alternately, the overall operation of the inverter device for driving the motor is performed. Improves reliability.

  On the other hand, when a malfunction occurs in the operating inverter main circuit component 51 or inverter main circuit component 52, the operation is automatically switched to the healthy inverter main circuit component 52 or inverter main circuit component 51 to the motor 3. However, when a malfunction occurs in the inverter main circuit configuration unit 51 or the inverter main circuit configuration unit 52 during operation, power supply to the motor 3 is temporarily stopped and a start switch 56a is newly provided. By pressing, it is possible to resume power supply by the healthy inverter main circuit configuration unit 52 or the inverter main circuit configuration unit 51.

  In the circuit configuration shown in FIG. 1 or FIG. 4 described above, an example in which a pump, a fan (not shown) is driven as a load of the motor 3 has been described. However, the motor driving device of the present invention is replaced with an AC power source. It can also be used as a driving device for a vehicle driving motor such as an electric vehicle using a storage battery as an input power source. In this case, the reliability of the driving device is increased, and it is possible to avoid the electric vehicle from being unable to run as much as possible.

1 is a circuit configuration diagram of an inverter device for driving an electric motor showing a first embodiment of the present invention. Flowchart for explaining the operation of FIG. Circuit configuration diagram for explaining the operation of FIG. Circuit diagram of an inverter device for driving an electric motor showing a second embodiment of the present invention Schematic conceptual diagram illustrating the configuration of FIG. Circuit configuration diagram of an inverter device for driving a motor showing a conventional example

DESCRIPTION OF SYMBOLS 1 ... AC power source, 2, 4, 5 ... Inverter device for motor drive, 3 ... Electric motor, 21 ... General-purpose inverter, 22, 23 ... Electromagnetic contactor, 24 ... Sequence circuit, 41, 42 ... Inverter unit 42, 43, 44 ... Electromagnetic contactor, 45 ... Alternative operation control circuit, 51, 52 ... Inverter main circuit component, 53 ... Inverter control circuit, 54,55 ... Electromagnetic contactor, 56 ... Alternative operation control circuit, 57 ... Heat sink, 57a, 57b ... Fan, 58 ... Temperature sensor.

Claims (3)

In an inverter device for driving a motor that generates AC power of variable voltage and variable frequency and drives the motor at a variable speed with the generated AC power, for generating at least AC power among the respective components constituting the inverter device When there are two sets of inverter main circuit components, and in normal times, when a stop command is given within a set time set in advance from the start command to one set of inverter main circuit components in operation Gives a command to switch the operation to the other set of inverter main circuit components in the standby state when a new start command is given thereafter, and sets the setting to the one set of inverter main circuit components in operation. If no stop command is given in time, the operation is switched to the other set of inverter main circuit components waiting after the set time has elapsed. By giving a command to change, the two sets of inverter main circuit components are alternately operated, and when a fault is detected in one set of inverter main circuit components, this one set of inverter main circuit components is operated. Alternate operation control that stops operation of the inverter main circuit component and gives a command to switch the operation to the other set of inverter main circuit components that are on standby and switches the operation to the other inverter main circuit component on standby motor driving inverter apparatus comprising the means.   2. The motor drive inverter device according to claim 1, wherein the two sets of main circuit components are mounted on a common heat sink.   The inverter device for driving an electric motor according to claim 2, wherein two sets of fans for cooling the heat sink are provided, and each set of fans is operated alternately one by one in a normal state. When detected, an inverter device for driving a motor, wherein the operation is switched to the other set of fans.

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