WO2018020657A1

WO2018020657A1 - Power converting device and air conditioner

Info

Publication number: WO2018020657A1
Application number: PCT/JP2016/072311
Authority: WO
Inventors: 憲嗣岩崎; 成雄梅原; 有澤　浩一
Original assignee: 三菱電機株式会社
Priority date: 2016-07-29
Filing date: 2016-07-29
Publication date: 2018-02-01
Also published as: JPWO2018020657A1

Abstract

A power converting device includes a first power converting circuit (3), a second power converting circuit (4), a first charge/discharge unit (1), and a second charge/discharge unit (2). The first power converting circuit (3) and the second power converting circuit (4) convert the power of a power supply (130) into power to be output to a load. The first charge/discharge unit (1) and the second charge/discharge unit (2) are connected to the first power converting circuit (3) and the second power converting circuit (4) respectively and charged by the power supply (130). The second charge/discharge unit (2) has capacitance smaller than the capacitance of the first charge/discharge unit (1).

Description

Power converter and air conditioner

The present invention relates to a power conversion device including a plurality of power conversion circuits that convert power output to a load such as a motor, and an air conditioner including the power conversion device.

Conventionally, in a device driven by a motor, a motor using a plurality of windings has been used to ensure reliability. For example, in a device using a double three-phase motor with two windings, even if a problem occurs in one winding, the motor can be driven using the other winding and the operation continues. Can be made. In particular, in a device using a double three-phase motor, it is possible to configure a device that ensures reliability by connecting a power conversion device as an inverter to each electrically independent winding. it can. Patent Document 1 discloses an apparatus in which a first inverter is electrically connected to a first winding of a double three-phase motor, and a second inverter is electrically connected to a second winding. Patent Document 1 discloses a structure in which a first capacitor is connected to the first inverter as a smoothing capacitor, and a second capacitor is connected to the second inverter as a smoothing capacitor.

In order to ensure the reliability of a device driven by a motor, it is necessary to ensure the reliability of the power conversion device itself in addition to using a plurality of motor windings. For example, the power converter uses a film capacitor as the smoothing capacitor connected to the input unit of the inverter. The film capacitor is more reliable and has a longer life than the electrolytic capacitor because of its structure. Patent Document 2 discloses a structure in which the smoothing capacitor connected to the subsequent stage of the diode bridge of the inverter is a film capacitor.

JP-A-2015-198542 JP 2010-112585 A

∙ Conventional power converters connected to double three-phase motors often use large-capacity electrolytic capacitors as smoothing capacitors. Conventional power converters use a large-capacitance electrolytic capacitor for the smoothing capacitor, so that the input voltage can be maintained using the charge stored in the electrolytic capacitor even when an instantaneous voltage drop occurs in the power supply connected to the power converter. Was. However, since the electrolytic capacitor has a large volume, there is a problem that the size of the power conversion device is increased. Moreover, since the price of the electrolytic capacitor increases as the capacity increases, there is a problem that the cost of the power conversion device increases. Furthermore, the electrolytic capacitor is weaker than heat as compared with the film capacitor, and there is a problem that the life is likely to be shortened when the electrolytic capacitor is disposed near the heat generating motor.

When a film capacitor is used as the smoothing capacitor, the power conversion device can reduce the size and cost of the device in addition to ensuring reliability. However, the film capacitor has a smaller capacity than the electrolytic capacitor. For this reason, when a film capacitor is used as the smoothing capacitor, the input voltage of the power conversion device is abruptly reduced each time an instantaneous voltage drop occurs in the power supply. When a conventional power conversion device is connected to a motor, the driving of the motor is stopped each time an instantaneous voltage drop occurs in the power supply. In particular, when a conventional power conversion device is connected to the motor used in the compressor of the air conditioner, the operation of the air conditioner stops and causes discomfort to the user whenever an instantaneous voltage drop occurs in the power supply. become. In particular, there is a problem that the air conditioner cannot be operated satisfactorily in an area where the occurrence frequency of instantaneous voltage drop is high in the power source.

The present invention is an invention for solving the above-described problems, and maintains an input voltage even when an instantaneous voltage drop occurs in a power supply while reducing the size and cost of the apparatus. An object of the present invention is to provide a power conversion device capable of performing the above and an air conditioner including the power conversion device.

The power conversion device of the present invention is connected to a power source, converts the power of the power source into power to be output to the load, and is connected to the power source, and converts the power of the power source into power to be output to the load. A second power conversion circuit, a first charging / discharging unit connected to the first power conversion circuit and charged by the power source, and a second charging unit connected to the second power conversion circuit and charged by the power source And a capacitance of the second charging / discharging unit is smaller than a capacitance of the first charging / discharging unit.

The air conditioner of the present invention includes the above-described power converter, a motor driven by the power output from the power converter, and a compressor operated by the motor.

According to the present invention, the power conversion device can reduce the size and cost of the device at the second charging / discharging unit, and can reduce the cost at the first charging / discharging unit even when an instantaneous voltage drop occurs at the power source. The input voltage can be maintained.

It is a block diagram which shows the structure and application example of the power converter device which concerns on Embodiment 1 of this invention. It is a circuit diagram which shows an example of the charging / discharging part of the power converter device which concerns on Embodiment 1 of this invention. It is a timing chart which shows operation | movement when the instantaneous voltage drop generate | occur | produces in the power supply in the power converter device which concerns on Embodiment 1 of this invention. It is a flowchart which shows operation | movement of the power converter device which concerns on Embodiment 1 of this invention. It is a block diagram which shows the structure and application example of the power converter device which concerns on Embodiment 2 of this invention. It is a block diagram which shows another structure of the power converter device which concerns on Embodiment 2 of this invention. It is a flowchart which shows operation | movement of the power converter device of another structure which concerns on Embodiment 2 of this invention. It is a block diagram which shows the structure and application example of the power converter device which concerns on Embodiment 3 of this invention. It is a block diagram which shows the structure and application example of the power converter device which concerns on Embodiment 4 of this invention. It is a block diagram which shows the structure and application example of the power converter device which concerns on Embodiment 5 of this invention. It is a block diagram which shows the structure and application example of the power converter device which concerns on Embodiment 6 of this invention. It is the schematic which shows the air conditioning apparatus which concerns on Embodiment 7 of this invention.

Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings.
Embodiment 1 FIG.
FIG. 1 is a block diagram showing a configuration and an application example of the power conversion apparatus according to Embodiment 1 of the present invention. The power conversion device shown in FIG. 1 converts the power supplied from the power supply 130 to generate driving power for the motor 7. A first power conversion circuit 3 connected to the power source 130, the first winding 5 of the double three-phase motor 7, and a second power conversion circuit 4 connected to the second winding 6 of the double three-phase motor 7. And. Furthermore, the power conversion device includes a first charging / discharging unit 1 connected to the input side of the first power conversion circuit 3 and a second charging / discharging unit 2 connected to the input side of the second power conversion circuit 4. ing. The first power conversion circuit 3 and the second power conversion circuit 4 are connected to a common power supply 130 in parallel. Note that the first power conversion circuit 3 and the second power conversion circuit 4 may be connected to separate power supplies 130, respectively.

The first power conversion circuit 3 and the second power conversion circuit 4 are configured by, for example, inverter circuits, and two upper and lower switching elements (for example, IGBT (insulated gate bipolar) corresponding to each of the U phase, the V phase, and the W phase. Transistor). The first power conversion circuit 3 and the second power conversion circuit 4 are not limited to a three-phase inverter circuit, and may be a two-phase inverter circuit as long as it is connected to a two-phase motor.

The 1st charging / discharging part 1 (1st charging / discharging part) and the 2nd charging / discharging part 2 (2nd charging / discharging part) have 1 each of charging / discharging components, and the 2nd charging / discharging part 2 is Compared with the 1st charging / discharging part 1, an electrostatic capacitance is small. That is, for example, a large-capacity electrolytic capacitor is used for the first charging / discharging unit 1, and a small-capacity film capacitor is used for the second charging / discharging unit 2, for example. In addition, although the electrolytic capacitor and the film capacitor are used for charging / discharging components, other components which can be charged / discharged, for example, an electric double layer capacitor, etc. may be used.

The power conversion device further includes a control unit 12 that controls each of the first power conversion circuit 3 and the second power conversion circuit 4. The control unit 12 controls the first power conversion circuit 3 based on the detection results of the first current sensor 8 and the second current sensor 9 that detect the output current of the first power conversion circuit 3. The second power conversion circuit 4 is controlled based on the detection results of the third current sensor 10 and the fourth current sensor 11 that detect the output current.

1, the case where the number of electrically independent windings and the number of power conversion circuits is two will be described as a specific example of the present embodiment, but the present invention is not limited to this. The present invention may be applied to a power conversion device in which the number of electrically independent windings and the number of power conversion circuits are n (where is a natural number of 2 or more). Further, when the number of power conversion circuits is n, the number of charge / discharge units is also n. Among the n charging / discharging units, the respective capacitances from the (m + 1) th charging / discharging unit (m <n, m are natural numbers) to the nth charging / discharging unit are changed from the first charging / discharging unit to the mth charging / discharging unit. It is smaller than each electrostatic capacity to the discharge part.

In the power conversion device according to the present embodiment, a first power conversion circuit 3 and a second power conversion circuit 4 are respectively provided in a motor 7 having electrically independent windings (first winding 5 and second winding 6). The first charging / discharging unit 1 is connected to the input unit of the first power conversion circuit 3, and the second charging / discharging unit 2 is connected to the input unit of the second power conversion circuit 4.

The first charging / discharging unit 1 and the second charging / discharging unit 2 have been described as being configured by a single charging / discharging component as illustrated in FIG. 1, but are not limited thereto. FIG. 2 is a circuit diagram showing an example of a charge / discharge unit of the power conversion device according to Embodiment 1 of the present invention. The 1st charging / discharging part 1 shown in FIG. 2 has several charging / discharging components connected in series or in parallel. Specifically, the first charging / discharging unit 1 includes a first electrolytic capacitor 1a and a second electrolytic capacitor 1b connected in series, a third electrolytic capacitor 1c and a fourth electrolytic capacitor 1d connected in series, The electrolytic capacitor 1a and the third electrolytic capacitor 1c are connected in parallel, and the second electrolytic capacitor 1b and the fourth electrolytic capacitor 1d are connected in parallel. Furthermore, in the 1st charging / discharging part 1, the 1st balance resistor 1e and the 2nd balance resistor 1f which are accompanying passive elements are connected in parallel with the 1st electrolytic capacitor 1a and the 2nd electrolytic capacitor 1b.

By configuring like the first charging / discharging unit 1 shown in FIG. 2, the withstand voltage of the first charging / discharging unit 1 can be increased. That is, by combining a plurality of low breakdown voltage capacitors, it is possible to increase the breakdown voltage of the entire charging / discharging unit, eliminating the need for expensive high breakdown voltage capacitors, and reducing costs. Specifically, when a power converter having a withstand voltage of 200V is changed to a power converter having a withstand voltage of 400V, the charge / discharge part (capacitor) having a withstand voltage of 200V is changed to a charge / discharge part (capacitor) having a withstand voltage of 400V. Instead, as shown in FIG. 2, a plurality of charge / discharge portions (capacitors) having a withstand voltage of 200 V are combined. Thereby, although the number of parts to use increases, cost can be reduced by using parts with a low unit price and sharing parts with a plurality of devices. In addition, although the 1st charging / discharging part 1 was demonstrated in FIG. 2, you may apply the structure shown in FIG. Moreover, although FIG. 2 demonstrated the structure which combined the some electrolytic capacitor, you may comprise combining other charge / discharge components, such as a film capacitor.

Next, the operation of the power converter according to the present embodiment when an instantaneous voltage drop occurs in the power supply 130 will be described. FIG. 3 is a timing chart showing an operation when an instantaneous voltage drop occurs in power supply 130 in the power conversion apparatus according to Embodiment 1 of the present invention. In the power conversion device according to the present embodiment, when an instantaneous voltage drop occurs in the power supply 130, the second power conversion circuit 4 has an input voltage due to the instantaneous voltage drop because the capacitance of the second charging / discharging unit 2 is small. The change is stopped without being covered, and the torque generated becomes 0 (zero) as shown in FIG. On the other hand, since the first power conversion circuit 3 has a large capacitance of the first charging / discharging unit 1, the change in the input voltage is covered by the instantaneous voltage drop and the generated torque is maintained. Further, the first power conversion circuit 3 performs control to maintain the rotation speed of the motor 7 even when the second power conversion circuit 4 is stopped, and thus the torque generated temporarily increases.

However, since the controller 12 reduces the rotational speed of the motor 7, the torque generated by the first power conversion circuit 3 is returned to the original torque. The rotation speed of the motor 7 starts to decrease from when the instantaneous voltage drop occurs at the power source 130 and decreases to a certain power failure protection rotation speed. During the period in which the instantaneous voltage drop occurs, the rotation speed of the motor 7 maintains the power failure protection rotation speed, and returns to the normal rotation speed when the instantaneous voltage drop is resolved. That is, the control unit 12 resumes the operation of the second power conversion circuit 4 when the instantaneous voltage drop is resolved.

Furthermore, the operation of the power conversion device according to the present embodiment will be described using a flowchart. FIG. 4 is a flowchart showing the operation of the power conversion apparatus according to Embodiment 1 of the present invention. First, when the first power conversion circuit 3 and the second power conversion circuit 4 are stopped, the control unit 12 determines that the output command value of the power input to the control unit 12 is greater than the output power capacity of the second power conversion circuit 4. It is determined whether it is small (step S101).

When the output command value is smaller than the output power capacity of the second power conversion circuit 4 (step S101: YES), the control unit 12 activates only the second power conversion circuit 4 with the first power conversion circuit 3 stopped. (Step S101a). The control part 12 returns a process to step S101 after step S101a, and judges whether there is any change in an output command value. When the output command value is greater than or equal to the output power capacity of the second power conversion circuit 4 (step S101: NO), the control unit 12 activates the first power conversion circuit 3 and the second power conversion circuit 4 (step S102).

Next, the control unit 12 detects whether or not an instantaneous voltage drop has occurred in the power supply 130 (step S103). Specifically, the control unit 12 monitors whether or not an instantaneous voltage drop has occurred in the power supply 130 by monitoring the voltages of the first charging / discharging unit 1 and the second charging / discharging unit 2 as shown in FIG. Detected. The control unit 12 may directly detect the voltage of the power supply 130 instead of monitoring the voltages of the first charging / discharging unit 1 and the second charging / discharging unit 2.

When the controller 12 does not detect that an instantaneous voltage drop has occurred in the power supply 130 (step S103: NO), the control unit 12 returns the process to step S103 and monitors the occurrence of the instantaneous voltage drop in the power supply 130. On the other hand, when the controller 12 detects that an instantaneous voltage drop has occurred in the power supply 130 (step S103: YES), the controller 12 stops the operation of the second power conversion circuit 4 (step S103a). And the control part 12 starts the protection driving mode which reduces the rotation speed of the motor 7 to a power failure protection rotation speed, as demonstrated in FIG. 3 (step S103b).

Next, the control unit 12 detects whether or not the instantaneous voltage drop generated by the power supply 130 has been recovered (step S104). Specifically, as shown in FIG. 1, the control unit 12 monitors the voltages of the first charging / discharging unit 1 and the second charging / discharging unit 2 to determine whether or not the instantaneous voltage drop generated in the power supply 130 has been recovered. Is detected.

Control part 12 starts the 2nd power converter circuit 4 (Step S103c), when detecting having returned from a momentary voltage drop which occurred with power supply 130 (Step S104: YES). And the control part 12 complete | finishes protection operation mode, and returns the rotation speed of the motor 7 to a normal rotation speed (step S103d). On the other hand, when it is not possible to detect that the recovery from the instantaneous voltage drop generated by the power supply 130 is detected (step S104: NO), the control unit 12 determines whether the operation time in the protection operation mode has exceeded the protection operation possible time. (Step S105). Specifically, the control unit 12 activates a timer that measures the protected operation time during the process in step S103b, and determines whether the time measured by the timer has exceeded the protected operation possible time.

When the operation time in the protection operation mode does not exceed the protection operation possible time (step S105: NO), the control unit 12 returns the process to step S104 and monitors the operation time in the protection operation mode. On the other hand, when the operation time in the protection operation mode exceeds the protection operation possible time (step S105: YES), the control unit 12 stops the operation of the first power conversion circuit 3 (step S106). And the control part 12 notifies that the power failure abnormality generate | occur | produced (step S107). Specifically, the control unit 12 indicates that a power failure has occurred by displaying an error code on a connected monitor (not shown) or outputting an error message to a speaker (not shown). Notice.

As described above, the power conversion device according to the present embodiment includes the first charging / discharging unit 1 connected to the first power conversion circuit 3 and the second charging / discharging unit 2 connected to the second power conversion circuit 4. And. The first power conversion circuit 3 and the second power conversion circuit 4 are connected to the power source 130 and convert the power of the power source 130 into power output to the motor 7 (load). First charging / discharging unit 1 and second charging / discharging unit 2 are connected to each of first power conversion circuit 3 and second power conversion circuit 4 and are charged by power supply 130. The capacitance of the second charging / discharging unit 2 is smaller than the capacitance of the first charging / discharging unit 1. For this reason, the power conversion device according to the present embodiment has the first charge / discharge even when an instantaneous voltage drop occurs in the power supply 130 while the second charge / discharge unit 2 reduces the size and cost of the device. The input voltage which can continue rotation of the motor 7 in the part 1 can be maintained.

In addition, in the power converter device which concerns on this Embodiment, although the 1st charging / discharging part 1, the 2nd charging / discharging part 2, and the case where there were two charging / discharging parts were demonstrated, the 1st charging / discharging part to nth charging / discharging. You may generalize to n charge / discharge parts up to the part. When the power conversion device includes n charging / discharging units, a power conversion circuit is connected to each charging / discharging unit, and thus n power conversion circuits are required. In addition, each capacitance from the (m + 1) th charging / discharging unit to the nth charging / discharging unit is smaller than each capacitance from the first charging / discharging unit to the mth charging / discharging unit.

The power conversion device according to the present embodiment further includes a control unit that controls each of the first power conversion circuit 3 and the second power conversion circuit 4. Therefore, the power conversion device can start and stop the necessary power conversion circuit according to the output voltage required for the load.

Furthermore, although the power converter according to the present embodiment has been described that the load that outputs the power converted by the first power converter circuit 3 and the second power converter circuit 4 is the motor 7, it is not limited thereto. The same effect can be obtained even with a load other than the motor.

Further, in the power conversion device according to the present embodiment, the control unit 12 stops the first power conversion circuit 3 when the necessary power of the motor 7 is smaller than the output power of the second power conversion circuit 4. Energy consumption can be reduced. When generalized to n power conversion circuits from the first power conversion circuit 3 to the nth power conversion circuit, the control unit 12 determines that the required power of the motor 7 is from the (m + 1) th power conversion circuit to the nth power conversion circuit. When it is smaller than the total output power up to the power conversion circuit, the first power conversion circuit 3 to the m-th power conversion circuit are stopped.

Furthermore, in the power conversion device according to the present embodiment, the control unit 12 causes the voltage of the second charging / discharging unit 2 to be a constant value when the voltage of the power supply 130 is reduced to a certain value or less (for example, an instantaneous voltage drop). In the case of the following, the second power conversion circuit 4 is stopped while the first power conversion circuit 3 is operated, so that the rotation speed of the motor 7 can be maintained at the power failure protection rotation speed. Note that when generalized to n power conversion circuits from the first power conversion circuit 3 to the nth power conversion circuit, the control unit 12 reduces the voltage of the power supply 130 to a predetermined value or less, so that (m + 1) th When the voltage from the charging / discharging unit to the nth charging / discharging unit becomes a certain value or less, the (m + 1) th power conversion circuit to the nth power conversion circuit are stopped, while the first power conversion circuit 3 to the mth power Operate up to the conversion circuit.

In the power conversion device according to the present embodiment, the motor 7 has the first winding 5 and the second winding 6 that are electrically independent, and the first power conversion circuit 3 and the second power conversion circuit 4. However, since it is connected to each of the first winding 5 and the second winding 6, the motor 7 can be driven even if one of the power conversion circuits is stopped.

Embodiment 2. FIG.
In the power conversion device according to Embodiment 1 of the present invention, each of first charging / discharging unit 1 and second charging / discharging unit 2 is connected to power supply 130. In the power conversion device according to Embodiment 2 of the present invention, a configuration in which the charging / discharging unit is connected to an AC power supply via a rectifier circuit will be described. FIG. 5 is a block diagram showing a configuration and an application example of the power conversion apparatus according to Embodiment 2 of the present invention. In FIG. 5, the same components as those described in the power conversion device according to Embodiment 1 of the present invention are denoted by the same reference numerals and detailed description thereof is omitted.

In the power converter shown in FIG. 5, the first charging / discharging unit 1 is connected to the single-phase AC power source 13 via the rectifier circuit 14, and the second charging / discharging unit 2 is connected to the AC power source 13 via the rectifier circuit 15. It is connected. The

rectifier circuits

14 and 15 are, for example, full-wave rectifier circuits configured by diode bridges for full-wave rectification of the AC input voltage supplied from the AC power supply 13. The inputs of the

rectifier circuits

14 and 15 are connected to one AC power source 13, but different AC power sources may be connected to each other.

The power conversion device according to the present embodiment can further be provided with a switching circuit on the output side of the second charging / discharging unit 2. FIG. 6 is a block diagram showing another configuration of the power conversion apparatus according to Embodiment 2 of the present invention. In FIG. 6, the same components as those described in the power conversion device according to Embodiment 1 of the present invention and the power conversion device shown in FIG. 5 are denoted by the same reference numerals, and detailed description thereof is omitted.

6, an open / close circuit is provided between the second power conversion circuit 4 and the second charging / discharging unit 2. The open / close circuit is a switch circuit 16 provided on the wiring connected to the cathode side of the diode constituting the rectifier circuit 15. In the power conversion device according to FIG. 6, when the second power conversion circuit 4 is stopped, the switch circuit 16 causes the regenerative current from the motor 7 that is a load to flow toward the second charge / discharge unit 2. Can be blocked. Therefore, in the power conversion device shown in FIG. 6, when the instantaneous voltage drop occurs in the AC power supply 13 and the second power conversion circuit 4 is stopped, the regenerative current from the motor 7 is cut off by the switch circuit 16. It is possible to prevent the voltage of the second charging / discharging unit 2 from rising and being destroyed beyond the breakdown voltage. That is, the switch circuit 16 prevents the regenerative current from flowing and protects the second charging / discharging unit 2.

Next, the operation of the power conversion apparatus shown in FIG. 6 will be described using a flowchart. FIG. 7 is a flowchart showing the operation of the power conversion device of another configuration according to Embodiment 2 of the present invention. In FIG. 7, the same processes as those in the flowchart showing the operation of the power conversion device according to Embodiment 1 of the present invention shown in FIG. 4 are denoted by the same reference numerals, and detailed description thereof is omitted. First, the control unit 12 determines whether or not the output command value of the input power is smaller than the output power capacity of the second power conversion circuit 4 (step S101).

When the output command value is smaller than the output power capacity of the second power conversion circuit 4 (step S101: YES), the control unit 12 activates only the second power conversion circuit 4 with the first power conversion circuit 3 stopped. (Step S101a). When the output command value is greater than or equal to the output power capacity of the second power conversion circuit 4 (step S101: NO), the control unit 12 activates the first power conversion circuit 3 and the second power conversion circuit 4 (step S102).

Next, the control unit 12 detects whether or not an instantaneous voltage drop has occurred in the AC power supply 13 (step S103). When the controller 12 does not detect that an instantaneous voltage drop has occurred in the AC power supply 13 (step S103: NO), the control unit 12 returns the process to step S103 and monitors the occurrence of the instantaneous voltage drop in the AC power supply 13. On the other hand, when the controller 12 detects that an instantaneous voltage drop has occurred in the AC power supply 13 (step S103: YES), the controller 12 stops the operation of the second power conversion circuit 4 (step S103a). Further, the control unit 12 opens the switch circuit 16 in order to cut off the regenerative current to the second charging / discharging unit 2 (step S103e). And the control part 12 starts the protection driving mode which reduces the rotation speed of the motor 7 to a power failure protection rotation speed (step S103b).

Next, the control unit 12 detects whether or not the instantaneous voltage drop generated by the AC power supply 13 has been recovered (step S104). When the control unit 12 detects that the instantaneous voltage drop generated in the AC power supply 13 has recovered (step S104: YES), the control unit 12 closes (short-circuits) the switch circuit 16 to supply power to the second power conversion circuit 4. (Step S103f). Furthermore, the control part 12 starts the 2nd power converter circuit 4 (step S103c). And the control part 12 complete | finishes protection operation mode, and returns the rotation speed of the motor 7 to a normal rotation speed (step S103d). On the other hand, when the control unit 12 cannot detect that the instantaneous voltage drop generated in the AC power supply 13 has recovered (step S104: NO), it is determined whether or not the operation time in the protection operation mode exceeds the protection operation possible time. Judgment is made (step S105).

When the operation time in the protection operation mode does not exceed the protection operation possible time (step S105: NO), the control unit 12 returns the process to step S104 and monitors the operation time in the protection operation mode. On the other hand, when the operation time in the protection operation mode exceeds the protection operation possible time (step S105: YES), the control unit 12 stops the operation of the first power conversion circuit 3 (step S106). And the control part 12 notifies that the power failure abnormality generate | occur | produced (step S107).

As described above, in the power conversion device with another configuration according to the second embodiment of the present invention, the switch circuit 16 is further provided on the output side of the second charge / discharge unit 2. A regenerative current can be interrupted | blocked and the 2nd charging / discharging part 2 can be protected. In addition, when generalizing into n charging / discharging parts from the 1st charging / discharging part 1 to the nth charging / discharging part, the control part 12 will each charge from the (m + 1) th charging / discharging part to the nth charging / discharging part. An opening / closing circuit is further provided on the output side of the discharge unit.

Further, in the power conversion device having another configuration according to the second embodiment of the present invention, the switch circuit 16 is opened when the second power conversion circuit 4 is stopped, so that an instantaneous voltage drop occurs in the AC power supply 13. Thus, when the second power conversion circuit 4 is stopped, the regenerative current from the motor 7 can be cut off by the switch circuit 16, and the second charging / discharging unit 2 can be prevented from being destroyed. In general, when the number of power conversion circuits from the first power conversion circuit 3 to the nth power conversion circuit is generalized, the switching circuit stops when the (m + 1) th power conversion circuit to the nth power conversion circuit are stopped. ,Open.

Further, in the power conversion device having another configuration according to the second embodiment of the present invention, the switch circuit 16 is closed when the second power conversion circuit 4 is operated, so that an instantaneous voltage drop occurs in the AC power supply 13. The second power conversion circuit 4 can be operated by the AC power supply 13 except when the second power conversion circuit 4 is stopped. Note that when generalized to n power conversion circuits from the first power conversion circuit 3 to the nth power conversion circuit, the switching circuit is used when operating from the (m + 1) th power conversion circuit to the nth power conversion circuit. ,close.

Embodiment 3 FIG.
In the power conversion device according to Embodiment 3 of the present invention, a configuration in which a rectifier circuit connected to the first charging / discharging unit 1 and the second charging / discharging unit 2 is shared will be described. FIG. 8 is a block diagram showing a configuration and an application example of the power conversion apparatus according to Embodiment 3 of the present invention. In addition, in FIG. 8, about the same structure as the structure demonstrated with the power converter device which concerns on

Embodiment

1, 2, the same code | symbol is attached | subjected and detailed description is abbreviate | omitted.

In the power converter shown in FIG. 8, the rectifier circuit 14 connected to the input side of the first charging / discharging unit 1 and the second charging / discharging unit 2 is common. In the power conversion device shown in FIG. 8, the first power conversion circuit 3 and the second power conversion circuit 4 are connected to the first charging / discharging unit 1 and the second charging / discharging unit 2 connected to the common rectifier circuit 14. Then, electric power is supplied to the motor 7.

Also in the power conversion device shown in FIG. 8, when an instantaneous voltage drop occurs in the AC power supply 13 and the second power conversion circuit 4 stops, a regenerative current flows from the motor 7, but the input of the first charging / discharging unit 1 Since the reactor 17 is provided on the side, the regenerative current is absorbed by the first charging / discharging unit 1 through the reactor 17. Therefore, the regenerative current from the motor 7 is absorbed by the first charging / discharging unit 1 through the reactor 17 to prevent the voltage of the second charging / discharging unit 2 from rising and being destroyed beyond the breakdown voltage. can do. That is, the reactor 17 protects the second charging / discharging unit 2 from the regenerative current.

As described above, since the power conversion device according to Embodiment 3 of the present invention further includes the reactor 17 on the input side of the first charging / discharging unit 1, the first charging / discharging unit 1 absorbs the regenerative current. The second charging / discharging unit 2 can be protected. Furthermore, in the power converter device according to Embodiment 3 of the present invention, the first charging / discharging unit 1 can be charged using the regenerative current, and the power can be used effectively. In addition, when generalizing to n charging / discharging parts from the 1st charging / discharging part 1 to the nth charging / discharging part, at least one charging / discharging part of the 1st charging / discharging part 1 to the mth charging / discharging part A reactor is further provided on the input side.

Embodiment 4 FIG.
In the power conversion device according to Embodiment 4 of the present invention, a configuration for supplying power to a plurality of independent loads will be described. FIG. 9 is a block diagram showing a configuration and an application example of the power conversion device according to Embodiment 4 of the present invention. In FIG. 9, the same components as those described in the power conversion devices according to Embodiments 1 to 3 of the present invention are denoted by the same reference numerals, and detailed description thereof is omitted.

9, the first power conversion circuit 3 is connected to the motor 18, and the second power conversion circuit 4 is connected to the motor 19 independent of the motor 18. Thereby, the power converter device shown in FIG. 9 can drive a plurality of independent motors (loads) by one power converter device.

When generalized to n power conversion circuits from the first power conversion circuit 3 to the nth power conversion circuit, an independent motor is connected to each of the n power conversion circuits. The n power conversion circuits may be divided into a plurality of groups, and independent motors may be connected to each group. For example, the motor 18 is connected to the first group from the first power conversion circuit 3 to the mth power conversion circuit, and the motor 19 is connected to the second group from the (m + 1) th power conversion circuit to the nth power conversion circuit. May be.

Embodiment 5 FIG.
In the power conversion device according to Embodiment 5 of the present invention, a configuration in which a three-phase AC power supply is used as a power supply will be described. FIG. 10 is a block diagram showing a configuration and an application example of the power conversion apparatus according to Embodiment 5 of the present invention. In FIG. 10, the same components as those described in the power converters according to Embodiments 1 to 4 of the present invention are denoted by the same reference numerals, and detailed description thereof is omitted.

10, the power source connected to the rectifier circuit 14 common to the first charging / discharging unit 1 and the second charging / discharging unit 2 is the three-phase AC power source 13a. In the power conversion device shown in FIG. 10, the power of the three-phase AC power supply 13 a is converted by the first power conversion circuit 3 and the second power conversion circuit 4 and supplied to the motor 7. Thus, various types of power supplies can be used in the power conversion device shown in FIG.

Embodiment 6 FIG.
In the power conversion device according to Embodiment 6 of the present invention, a configuration in which a two-phase motor is used as a load will be described. FIG. 11: is a block diagram which shows the structure and application example of the power converter device which concerns on Embodiment 6 of this invention. In FIG. 11, the same components as those described in the power converters according to Embodiments 1 to 5 of the present invention are denoted by the same reference numerals, and detailed description thereof is omitted.

11, the load connected to the first power conversion circuit 3 and the second power conversion circuit 4 is the double two-phase motor 7a. Specifically, the double two-phase motor 7a includes a first winding 5a and a second winding 6a that are electrically independent, and the first winding 5a is connected to the first power conversion circuit 3 and the second winding. 6a is connected to the second power conversion circuit 4, respectively. As described above, the power conversion device shown in FIG. 11 can supply power to various types of loads. In addition, in the power converter device shown in FIG. 11, although the single phase alternating current power supply 13 is used, you may use a three phase alternating current power supply.

Embodiment 7 FIG.
Next, the case where the motor used in the compressor of the air conditioner is driven by the electric power output by the power conversion device according to Embodiments 1 to 6 of the present invention will be described. FIG. 12 is a schematic diagram showing an air-conditioning apparatus 100 according to Embodiment 7 of the present invention. The air conditioner 100 includes a compressor 1A, a four-way valve 2A, an outdoor heat exchanger 3A, an expansion valve 4A, and an indoor heat exchanger 5A. In the air conditioner 100, the refrigerant circuit 90A is configured by connecting the compressor 1A, the four-way valve 2A, the outdoor heat exchanger 3A, the expansion valve 4A, and the indoor heat exchanger 5A in order by piping. .

Compressor 1A is a variable capacity compressor that can discharge high-temperature and high-pressure refrigerant by compressing sucked refrigerant. The compressor 1A is operated by a motor (not shown), and the motor is connected to the power converter according to Embodiments 1 to 6 of the present invention (not shown), and is supplied from the power converter. Driven by electric power. The four-way valve 2A is a switching unit that can switch the flow direction of the refrigerant discharged from the compressor 1A according to the operation.

The outdoor heat exchanger 3A is a heat exchanger that functions as a condenser when performing a cooling operation and functions as an evaporator when performing a heating operation. The outdoor fan 31A is a blower that supplies outside air to the outdoor heat exchanger 3A and forms an air flow.

The expansion valve 4A decompresses and expands the refrigerant flowing out of the outdoor heat exchanger 3A when performing the cooling operation, and decompresses and expands the refrigerant flowing out of the indoor heat exchanger 5A when performing the heating operation.

The indoor heat exchanger 5A is a heat exchanger that functions as an evaporator when performing a cooling operation and functions as a condenser when performing a heating operation. The indoor fan 51A is a blower that supplies outside air to the indoor heat exchanger 5A and forms an air flow.

The outdoor refrigerant temperature sensor 32A is a temperature detection unit that detects the temperature of the refrigerant flowing through the outdoor heat exchanger 3A. The indoor side refrigerant temperature sensor 52A is a sensor that detects the temperature of the refrigerant flowing through the indoor heat exchanger 5A.

The outdoor temperature sensor 33A is a temperature detection unit that detects the outdoor temperature around the outdoor heat exchanger 3A. The controller 80A controls the four-way valve 2A to switch the direction in which the refrigerant discharged from the compressor 1A flows.

As described above, the air-conditioning apparatus 100 according to Embodiment 7 of the present invention includes the power converter according to Embodiments 1 to 6 of the present invention, the motor driven by the electric power output from the power converter, And a compressor operated by a motor. For this reason, in the air conditioner 100, the second charging / discharging unit 2 can reduce the size and cost of the power converter, and the power converter can perform the first charging / discharging even when an instantaneous voltage drop occurs in the power source. Since the input voltage which can continue rotation of a motor in the part 1 is maintained, a driving | operation can be continued, without stopping a cooling operation and a heating operation. Moreover, in the air conditioning apparatus 100, since a driving | operation is not stopped whenever an instantaneous voltage drop generate | occur | produces with a power supply, a user can utilize comfortably.

The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

1 1st charging / discharging part 2, 2nd charging / discharging part 3, 1st power conversion circuit, 4 2nd power conversion circuit, 5, 5a 1st winding, 6, 6a 2nd winding, 7, 7a, 18, 19 motor, 8 1st current sensor, 9 2nd current sensor, 10 3rd current sensor, 11 4th current sensor, 12 control unit, 13 AC power supply, 13a 3 phase AC power supply, 14, 15 rectifier circuit 16 switch circuit, 17 Reactor.

Claims

A first power conversion circuit connected to a power source and converting the power of the power source into power output to a load;
A second power conversion circuit that is connected to the power source and converts the power of the power source into power output to a load;
A first charging / discharging unit connected to the first power conversion circuit and charged by the power source;
A second charging / discharging unit connected to the second power conversion circuit and charged by the power source;
With
The capacitance of the second charging / discharging unit is a power conversion device that is smaller than the capacitance of the first charging / discharging unit.
The power converter according to claim 1, wherein the load that outputs the power converted by the first power conversion circuit and the second power conversion circuit is a motor.
The power converter according to claim 1 or 2, further comprising a reactor on an input side of the first charging / discharging unit.
The power converter according to claim 1 or 2, further comprising a switching circuit on an output side of the second charging / discharging unit.
5. The power conversion device according to claim 1, further comprising a control unit that controls each of the first power conversion circuit and the second power conversion circuit.
The control unit is connected to the first charging / discharging unit when power required for the load is smaller than output power of the second power conversion circuit connected to the second charging / discharging unit. The power conversion device according to claim 5, wherein the first power conversion circuit is stopped.
When the voltage of the second power conversion circuit connected to the second charging / discharging unit becomes equal to or lower than a predetermined value due to the voltage of the power supply being reduced to a predetermined value or lower, The power conversion device according to claim 5, wherein the first power conversion circuit connected to the first charging / discharging unit is operated while stopping the two power conversion circuits.
The power conversion device according to claim 4, wherein the switching circuit opens when the second power conversion circuit connected to the second charging / discharging unit is stopped.
The power conversion device according to claim 4, wherein the switching circuit is closed when the second power conversion circuit connected to the second charging / discharging unit is operated.
The motor has an electrically independent first winding and second winding;
The power converter according to claim 2, wherein the first winding is connected to the first power conversion circuit, and the second winding is connected to the second power conversion circuit.
The power converter according to claim 10, wherein the motor operates a compressor.
The power converter according to claim 11, wherein the compressor is used in an air conditioner.
The power conversion device according to any one of claims 1 to 10,
A motor driven by the power output by the power converter;
An air conditioner comprising a compressor operated by the motor.