JP2001037239A - Inverter apparatus and inverter system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make unnecessary an exclusive control power supply facilities to stably acquire the control power supply even for drop of power source voltage by providing a control unit power supply circuit for converting and supplying a DC power to the power of the control unit. SOLUTION: In this inverter apparatus 4a, the positive line of the DC main power supply line 3 is connected to the positive terminal of a DC/DC switching power supply 24 via a fuse 31 and a resistor 22, the negative line of the DC main power supply line 3 is connected to the negative terminal of the DC/DC switching power supply 24 and a smoothing capacitor 23 is connected between both terminals of this switching power supply 24. The DC/DC switching power supply 24 is given a DC power source smoothed with a smoothing capacitor 23 to convert this DC power source to the predetermined DC voltage with the switching control and to give such DC voltage to an inverter control unit 12. The fuse 31, diode 30, resistor 22, DC/DC switching power supply 24 and smoothing capacitor 23 form a power supply circuit of control unit.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a DC distribution type inverter device which converts supplied DC power into AC power of an arbitrary frequency and supplies it to the outside, and a DC distribution type inverter device and this inverter device. More particularly, the present invention relates to an improvement in a control power supply circuit of an inverter device.

[0002]

2. Description of the Related Art FIG. 4 is a block diagram showing a configuration example of an inverter system in which a plurality of conventional DC distribution type inverter devices share one converter. In this inverter system, a converter 2 converts three-phase AC power supplied from three-phase AC main power supply 1 to DC power.
And a plurality of inverter devices 4 which are supplied with the DC power converted by the converter 2 through the DC main power supply line 3, convert the DC power into arbitrary AC power and drive the respective motors 5.
And an insulating transformer 6 that is supplied with single-phase AC power from the three-phase AC main power supply 1 and supplies AC power for control to each inverter device 4 through an AC control power supply line 7.

FIG. 5 is a block diagram showing an example of the internal configuration of the inverter device 4. As shown in FIG. The inverter device 4 includes a main smoothing capacitor 10 (first capacitor) for smoothing the DC power supplied from the DC main power supply line 3 and an inverter that receives the DC power smoothed by the main smoothing capacitor 10 and converts the DC power to AC power. Main circuit 11 and inverter main circuit 1
1 and an inverter control unit 12 for controlling The inverter device 4 further includes a circuit breaker 20 for cutting off the AC control power supply line 7 and a rectifying circuit 21 for rectifying the single-phase AC power supplied through the AC control power supply line 7.
And

The rectifier circuit 21 is a diode bridge composed of four diodes. The anode of the diode 21a is connected to the cathode of the diode 21c. The anode of the diode 21b is connected to the cathode of the diode 21d. Each of the AC control power supply lines 7 is connected to a node, and the diodes 21a and 21
The common connection node of each cathode of b is a positive output node, and the common connection node of each anode of the diodes 21c and 21d is a negative output node.

The inverter device 4 also includes a smoothing capacitor 23 for smoothing the DC power rectified by the rectifier circuit 21.
And a resistor 22 for suppressing an inrush current when charging the smoothing capacitor 23 from the rectifier circuit 21, and an instantaneous power failure backup circuit 25 connected to both terminals of the smoothing capacitor 23.
And a DC / DC switching power supply unit 24 which is supplied with smoothed DC power by the smoothing capacitor 23, converts the DC power into a predetermined DC voltage by switching control, and supplies the DC voltage to the inverter control unit 12.

The momentary power failure backup circuit 25 includes a resistor 25
c is connected in parallel to the cathode of the diode 25a,
The diode 2 is connected to the positive electrode side of the smoothing capacitor 23.
5a and the capacitor 2 in series with the parallel circuit of the resistor 25c.
5b is connected. The capacitor 25b is normally charged through the resistor 25c. When the voltage across the smoothing capacitor 23 decreases due to a momentary power failure or the like, the capacitor 25b discharges through the diode 25a to back up the input voltage to the DC / DC switching power supply unit 24.

FIG. 6 is a circuit diagram showing an example of the internal configuration of converter 2. The converter 2 is a diode bridge composed of six diodes. The anode of the diode 2a is connected to the cathode of the diode 2d. The anode of the diode 2b is connected to the cathode of the diode 2e.
f, and each phase of the three-phase AC power supply 1 is connected to each connection node, and a diode 2
The common connection node of each cathode of a, 2b, 2c is a positive output node, and the common connection node of each anode of the diodes 2d, 2e, 2f is a negative output node.

FIG. 7 is a circuit diagram showing an example of the internal configuration of the inverter main circuit 11. This inverter main circuit 11
A bridge circuit composed of six IGBTs (insulated gate bipolar transistors) and six freewheeling diodes, the emitter of the IGBT 41a and the IGBT
The collector of the IGBT 41b is connected to the collector of the IGBT 41e, and the collector of the IGBT 41e is connected to the collector of the IGBT 41b.
The emitter of T41c and the collector of IGBT 41f are connected, each connection node becomes an output node of each phase of three-phase AC power, the common connection node of each collector of IGBTs 41a, 42b, 41c becomes a positive input node, and IGBT4
The common connection node of each of the emitters 1d, 41e, and 41f is a negative input node.

IGBTs 41a, 41b, 41c, 41
Each of the collectors of d, 41e and 41f has a freewheel diode 42a, 42b, 42c, 42d, 42e,
Each of the cathodes of 42f is an IGBT 41a, 41b, 41
Each of the emitters c, 41d, 41e, 41f has a freewheeling diode 42a, 42b, 42c, 42d,
The anodes of 42e and 42f are respectively connected. IGBTs 41a, 41b, 41c, 41d, 41
Switching control by PWM is performed by the inverter control unit 12 for each of the gates e and 41f.

FIG. 8 shows a DC / DC switching power supply unit 2.
4 is a block diagram showing an example of the internal configuration of FIG. This DC / D
The C switching power supply unit 24 is a PWM type flyback regulator. The DC power smoothed by the smoothing capacitor 23 is supplied to the primary coil of the transformer 24 c and the FET 24.
b and the gate of the FET 24b is connected to the PW
Switching control is performed by the M control unit 24a. A diode 24d (flyback diode) is connected in series to the secondary coil of the transformer 24c, a smoothing capacitor 24e is connected in parallel with the secondary coil and the diode 24d, and both terminals of the smoothing capacitor 24e are output terminals. In the DC / DC switching power supply unit 24 having such a configuration, the P / P switching the gate of the FET 24b is performed.
An AC voltage corresponding to the duty ratio of the pulse subjected to the WM control is generated in the secondary coil of the transformer 24c, and the AC voltage is rectified and smoothed, and given to the inverter control unit 12 as a predetermined DC voltage.

The operation of an inverter system having such a configuration and having a plurality of DC power distribution type inverter devices 4 sharing one converter 2 will be described. Converter 2
Rectifies the three-phase AC power supplied from the three-phase AC main power supply 1 and converts the rectified power into DC power. The DC power that has been forward-converted by the converter 2 is supplied to the plurality of inverter devices 4 through the DC main power supply line 3. The insulating transformer 6 is supplied with single-phase AC power from the three-phase AC main power supply 1 and supplies AC power for control to each inverter device 4 through the AC control power supply line 7.

In each inverter device 4, the main smoothing capacitor 10 smoothes the DC power supplied by the DC main power supply line 3, and the DC power smoothed by the main smoothing capacitor 10 is supplied to the inverter main circuit 11. In the inverter main circuit 11, switching control by PWM is performed by the inverter control unit 12, and the applied DC power is converted into three-phase AC power to drive the electric motor 5.

Each inverter device 4 includes a rectifier circuit 2
1 rectifies the single-phase AC power supplied through the AC control power supply line 7, and the rectified DC power is smoothed by the smoothing capacitor 23, and the DC / DC switching power supply 2
4 given. DC / DC switching power supply unit 24
Converts the supplied DC power into a predetermined DC voltage by switching control and supplies the DC voltage to the inverter control unit 12. The instantaneous power failure backup circuit 25 reduces the AC power supplied through the AC control power supply line 7 due to an instantaneous power failure or the like,
When the voltage of the smoothing capacitor 23 decreases, a current is supplied from the capacitor 25b to maintain the control power of the inverter control unit 12.

[0014]

In a conventional inverter system in which a plurality of DC distribution type inverter devices 4 share one converter 2, a control AC power supply is supplied to each inverter device 4 as described above. Need to
When the number of wirings is large and the number of inverter devices 4 is large, there is a problem that the size of the insulating transformer 6 needs to be increased. Also, if the voltage of the AC power supply drops due to a momentary power failure or the like, the control power supply cannot be maintained and the inverter control unit 1
2, the capacity of the smoothing capacitor 23 in the control power supply is increased or a dedicated backup circuit is required.

As a technique for supplying control power to the inverter device, a power supply input circuit of the inverter device capable of supplying power to the control circuit from either a main circuit input power source or an external input power source is disclosed in Japanese Patent Application Laid-Open No. 8-289556. Japanese Patent Application Laid-Open No. 6-225 discloses an inverter device disclosed in Japanese Patent Application Laid-Open Publication No. 6-225, in which a DC power supply is shared and a plurality of inverters are connected to the same DC power supply.
No. 516. The present invention has been made in view of the above-described circumstances, and when a plurality of DC power distribution type inverter devices share one converter, a dedicated control power supply is not required, and A DC-distribution-type inverter device that can stably secure control power even in the event of a power drop due to a power outage or the like, and an inverter system including the DC-distribution-type inverter device and a converter that supplies DC power to the inverter device The purpose is to provide.

[0016]

An inverter device according to a first aspect of the present invention comprises a first capacitor for smoothing supplied DC power, and converting the DC power smoothed by the first capacitor into AC power of an arbitrary frequency. And a control unit for driving and controlling the inverter, and a control unit power supply circuit for converting the supplied DC power to power supply for the control unit and supplying the converted power.

The inverter device according to the second invention is characterized in that the control unit power supply circuit has an excessive current preventing means for preventing an inflow of an excessive current of the supplied DC power.

According to a third aspect of the present invention, in the inverter device, the control unit power supply circuit includes a second capacitor for smoothing the supplied DC power, and a current limiting resistor for limiting an inrush current when charging the second capacitor. Is further provided.

The inverter device according to a fourth aspect of the present invention is characterized in that the control unit power supply circuit further includes a backflow prevention diode for preventing a backflow of current from the second capacitor.

The inverter device according to a fifth aspect of the present invention further includes an opening / closing circuit for turning on / off the supplied DC power between the control unit power supply circuit and the inverter, so as to turn on / off the DC power to the inverter. It is characterized by being done.

According to a sixth aspect of the present invention, there is provided an inverter system, wherein one or a plurality of the inverter devices according to any one of the first to fifth aspects and the supplied AC power is converted into DC power and supplied to the inverter device. And a converter.

[0022]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the drawings showing an embodiment. Embodiment 1 FIG. FIG. 1 is a block diagram illustrating a configuration of an inverter device according to a first embodiment of the present invention. The inverter device 4a includes a main smoothing capacitor 10 (first capacitor) for smoothing the DC power supplied through the DC main power supply line 3, and an inverter that receives the DC power smoothed by the main smoothing capacitor 10 and converts the DC power to AC power. Main circuit 1
1 and an inverter control unit 12 for controlling the inverter main circuit 11.

In the inverter device 4a, the positive side line of the DC main power supply line 3 is connected to the DC / DC switching power supply unit 24 via a fuse 31, a diode 30 (backflow prevention diode) connected in sequence and a resistor 22. Connected to the positive terminal, the negative line of the DC main power line 3
It is connected to the negative terminal of the C / DC switching power supply 24, and is connected between both terminals of the DC / DC switching power supply 24.
The smoothing capacitor 23 (second capacitor) is connected. The DC / DC switching power supply 24 is supplied with DC power smoothed by the smoothing capacitor 23, converts the DC power into a predetermined DC voltage by switching control, and supplies the DC voltage to the inverter control unit 12. The fuse 31, the diode 30, the resistor 22, the DC / DC switching power supply unit 24, and the smoothing capacitor 23 constitute a control unit power supply circuit.

An example of the internal configuration of the inverter main circuit 11 is as shown in the circuit diagram of FIG. The inverter main circuit 11 is a bridge circuit including six IGBTs (insulated gate bipolar transistors) and six freewheel diodes. The inverter main circuit 11 is connected to the emitter of the IGBT 41a and the collector of the IGBT 41d.
The emitter of the IGBT 41e is connected to the collector of the IGBT 41e, the emitter of the IGBT 41c is connected to the collector of the IGBT 41f, and each connection node becomes an output node of each phase of the three-phase AC power, and the IGBT 41a, 42b,
The common connection node of each collector of 41c is the positive input node,
The common connection nodes of the emitters of the IGBTs 41d, 41e, 41f are negative input nodes, respectively.

IGBTs 41a, 41b, 41c, 41
Each of the collectors of d, 41e and 41f has a freewheel diode 42a, 42b, 42c, 42d, 42e,
Each of the cathodes of 42f is an IGBT 41a, 41b, 41
Each of the emitters c, 41d, 41e, 41f has a freewheeling diode 42a, 42b, 42c, 42d,
The anodes of 42e and 42f are respectively connected. IGBTs 41a, 41b, 41c, 41d, 41
Switching control by PWM is performed by the inverter control unit 12 for each of the gates e and 41f.

An example of the internal configuration of the DC / DC switching power supply unit 24 is as shown in the block diagram of FIG.
The DC / DC switching power supply unit 24 is a PWM flyback regulator, and includes a smoothing capacitor 23.
Is supplied to the series circuit of the primary coil of the transformer 24c and the FET 24b, and the gate of the FET 24b is subjected to switching control by the PWM control unit 24a. The diode 24 is connected to the secondary coil of the transformer 24c.
d (flyback diode) are connected in series, and the smoothing capacitor 24 is connected in parallel with the secondary coil and the diode 24 d.
e is connected, and both terminals of the smoothing capacitor 24e are output terminals.

In the DC / DC switching power supply unit 24 having such a configuration, an AC voltage corresponding to the duty ratio of the PWM-controlled pulse for switching the gate of the FET 24b is generated in the secondary coil of the transformer 24c. The voltage is rectified and smoothed, and a predetermined DC voltage is applied to the inverter control unit 12.

Hereinafter, the operation of the inverter device 4a having such a configuration will be described. In the inverter device 4a, the main smoothing capacitor 10 smoothes the DC power supplied by the DC main power supply line 3, and the DC power smoothed by the main smoothing capacitor 10 is supplied to the inverter main circuit 11. Inverter main circuit 11 is controlled by inverter control unit 12
The switching control by the WM is performed, and the supplied DC power is converted into three-phase AC power and output.

In the inverter device 4a, DC power from the DC main power supply line 3 is smoothed by a smoothing capacitor 23 through a fuse 31, a diode 30, and a resistor 22, and is supplied to a DC / DC switching power supply unit 24. . The fuse 31 (excessive current preventing means) prevents an excessive current of DC power from flowing from the DC main power supply line 3. The diode 30 prevents the current from flowing back from the smoothing capacitor 23. Resistor 22 limits an inrush current during charging from DC main power supply line 3 to smoothing capacitor 23.

For example, when the smoothing capacitor 23 or the like is short-circuited, the DC main power supply line 3 is also short-circuited, and the resistor 22 suppresses the short-circuit current, reduces the obligation to cut off the fuse 31, and blows the fuse 31. The operation of separating the short-circuited part is performed to prevent the spread of accidents at the time of short-circuit. Also,
The resistor 22 and the smoothing capacitor 23 have an effect of reducing the influence of disturbance and ripple voltage of the DC main power supply by a filter effect.

When the voltage of the DC main power supply line 3 drops due to an instantaneous power failure or the like, electric power is supplied to a load such as an electric motor by the electric charge charged in the main smoothing capacitor 10. As a result, the voltage across the main smoothing capacitor 10 decreases, and if this state continues, the inverter control 12 determines that the voltage of the DC main power supply is insufficient, and the inverter main circuit 11
Stop the operation of.

Generally, since the capacity of the control unit power supply circuit such as the DC / DC switching power supply unit 24 is much smaller than that of the inverter main circuit 11, the capacity of the main smoothing capacitor 10 when the inverter main circuit 11 does not operate is determined. The amount of discharge is very small, and the main smoothing capacitor 10 can continue supplying power to the control unit power supply circuit by discharging. Therefore, there is no need for an instantaneous power failure backup circuit of a dedicated control unit power supply circuit.
The diode 30 prevents the charge from flowing out of the smoothing capacitor 23 to the DC main power supply line 3 when the voltage of the DC main power supply line 3 decreases.

Embodiment 2 FIG. FIG. 2 is a block diagram showing a configuration of the second embodiment of the inverter device according to the present invention. The inverter device 4b is provided with a main smoothing capacitor 10 (first capacitor) for smoothing the DC power supplied through the DC main power supply line 3, and an inverter for receiving the DC power smoothed by the main smoothing capacitor 10 and converting the DC power to AC power. A main circuit 11 and an inverter control unit 12 for controlling the inverter main circuit 11 are provided.

In the inverter device 4b, the positive line of the DC main power supply line 3 is connected to the DC / DC switching power supply unit 24 via a fuse 31, a diode 30 (backflow prevention diode) connected in sequence and a resistor 22. Connected to the positive terminal, the negative line of the DC main power line 3
It is connected to the negative terminal of the C / DC switching power supply 24, and is connected between both terminals of the DC / DC switching power supply 24.
The smoothing capacitor 23 (second capacitor) is connected.

The DC / DC switching power supply unit 24 is supplied with the DC power smoothed by the smoothing capacitor 23, converts the DC power into a predetermined DC voltage by switching control, and supplies the DC voltage to the inverter control unit 12. Fuse 31, diode 3
The resistor 0, the resistor 22, the DC / DC switching power supply unit 24, and the smoothing capacitor 23 constitute a control unit power supply circuit. A DC main power supply line 3 is connected between a branch node of the DC main power supply line 3 to the control unit power supply circuit and the main smoothing capacitor 10.
An opening / closing circuit 13 for turning on / off between the inverter and the inverter main circuit 11 is provided.

The operation of the inverter device 4b having such a configuration will be described below. In the inverter device 4b, DC
The control unit power supply circuit such as the / DC switching power supply unit 24
Power is supplied from the primary side (DC main power side) of the switching circuit (switch circuit) 13. Therefore, when the switching circuit 13 is turned off, no current flows in the inverter main circuit 11 and only the control unit power supply circuit and the inverter control unit 12 can be operated, and the inverter control unit 12 alone can be operated. It becomes possible. Other operations are the same as the operations of the inverter device 4a described in the first embodiment, and thus the description is omitted.

Embodiment 3 FIG. 3 is a block diagram showing a configuration of the third embodiment of the inverter system according to the present invention. In this inverter system, a converter 2 for converting three-phase AC power supplied from a three-phase AC main power supply 1 into DC power, and DC power converted by the converter 2 are supplied through a DC main power supply line 3 to provide an arbitrary AC power. It is composed of a plurality of inverter devices 4a that convert the power into electric power and drive the respective electric motors 5, and there is no need for an insulating transformer 6 that supplies AC power for control to each inverter device 4a. Converter 2 rectifies the three-phase AC power supplied from three-phase AC main power supply 1 and performs forward conversion to DC power. The DC power that has been forward-converted by the converter 2 is supplied to the plurality of inverter devices 4 through the DC main power supply line 3.

An example of the internal configuration of the converter 2 is as shown in the circuit diagram of FIG. The converter 2 is a diode bridge composed of six diodes. The anode of the diode 2a is connected to the cathode of the diode 2d. The anode of the diode 2b is connected to the diode 2e.
Are connected, the anode of the diode 2c is connected to the cathode of the diode 2f, and each connection node is connected to each phase of the three-phase AC power supply 1,
The common connection node of each cathode of the diodes 2a, 2b, 2c is a positive output node, and the common connection node of each anode of the diodes 2d, 2e, 2f is a negative output node.

The operation of the inverter system having such a configuration will be described below. Converter 2 rectifies the three-phase AC power supplied from three-phase AC main power supply 1 and performs forward conversion to DC power. The direct-current power converted by the converter 2 is transmitted through the direct-current main power supply line 3 to a plurality of inverter devices 4a.
Supplied to In each inverter device 4a, the main smoothing capacitor 10 (FIG. 1) smoothes the DC power supplied by the DC main power supply line 3, and the DC power smoothed by the main smoothing capacitor 10 is converted into the inverter main circuit 11 (FIG. 1). Given to. The inverter main circuit 11 includes an inverter control unit 12
According to (FIG. 1), switching control by PWM is performed, and given DC power is converted into three-phase AC power,
The electric motor 5 is driven.

In each inverter device 4a, the supplied DC power is smoothed by a smoothing capacitor 23 (FIG. 1) and supplied to a DC / DC switching power supply unit 24 (FIG. 1). The DC / DC switching power supply unit 24 converts the supplied DC power into a predetermined DC voltage by switching control and supplies the DC power to the inverter control unit 12 (FIG. 1). As described above, this inverter system does not require a dedicated control power supply such as an insulating transformer.

[0041]

According to the inverter device of the first invention, the first capacitor smoothes the supplied DC power,
An inverter converts the DC power smoothed by the first capacitor into AC power of an arbitrary frequency and supplies the AC power to the outside. The control unit drives and controls the inverter, and the control unit power supply circuit converts the supplied DC power to power supply power of the control unit and supplies the power. This eliminates the need for a dedicated control power supply when a plurality of inverter devices share one converter.

According to the inverter device of the second invention,
The excessive current prevention means of the control unit power supply circuit prevents an excessive current of the supplied DC power from flowing. Therefore, when a plurality of DC distribution type inverter devices share one converter, a dedicated control power supply is used. No equipment is required, and it is possible to prevent the spread of accidents when a short circuit occurs.

According to the inverter device of the third aspect,
The second capacitor of the control unit power supply circuit smoothes the supplied DC power, and the current limiting resistor limits the inrush current to the second capacitor. Thereby, when a plurality of DC power distribution type inverter devices share one converter, a dedicated control power supply facility is not required, and a stable control power supply can be secured. In addition, due to the filtering effect of the current limiting resistor and the second capacitor, the influence of the disturbance on the main DC power supply and the ripple voltage can be reduced.

According to the inverter device of the fourth aspect,
Since the backflow prevention diode of the control unit power supply circuit prevents the backflow of the current from the second capacitor, when a plurality of DC distribution type inverter devices share one converter, dedicated control power supply equipment is not required. In addition, a control power supply can be stably secured even when the power supply drops due to a momentary power failure or the like.

According to the inverter device of the fifth aspect,
A switching circuit between the control unit power supply circuit and the inverter turns on / off the supplied DC power. Accordingly, when a plurality of inverter devices share one converter, a dedicated control power supply is not required, and the control unit can be operated without causing the inverter main circuit to perform power conversion. .

According to the inverter system of the sixth aspect, the converter converts the supplied AC power to DC power and supplies the DC power to one or more inverter devices according to any one of claims 1 to 5. Therefore, dedicated control power supply equipment is not required.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of an embodiment of an inverter device according to the present invention.

FIG. 2 is a block diagram showing a configuration of an embodiment of an inverter device according to the present invention.

FIG. 3 is a block diagram showing a configuration of an embodiment of an inverter system according to the present invention.

FIG. 4 is a block diagram illustrating a configuration example of a conventional inverter system.

FIG. 5 is a block diagram showing an example of an internal configuration of the inverter device.

FIG. 6 is a circuit diagram showing an example of an internal configuration of a converter.

FIG. 7 is a circuit diagram showing an example of an internal configuration of an inverter main circuit.

FIG. 8 is a block diagram illustrating an example of an internal configuration of a DC / DC switching power supply unit.

[Explanation of symbols]

2 Converter, 3 DC main power line, 4a, 4b
Inverter device, 10 main smoothing capacitor (first capacitor), 11 inverter main circuit, 12 inverter control unit, 13 switching circuit (switch circuit), 22 resistor, 23 smoothing capacitor (second capacitor, control unit power supply circuit), 24 DC / DC switching power supply unit (control unit power supply circuit), 24c transformer, 24d diode (flyback diode), 24e smoothing capacitor, 30 diode (backflow prevention diode), 31
fuse.

Claims (6)

[Claims] 1. A first capacitor for smoothing supplied DC power, an inverter for converting the DC power smoothed by the first capacitor to AC power of an arbitrary frequency and supplying the AC power to the outside, and drive control of the inverter And a control unit power supply circuit that converts the supplied DC power into power supply power of the control unit and supplies the power. 2. The inverter device according to claim 1, wherein the control unit power supply circuit has an excessive current preventing means for preventing an excessive current of the supplied DC power from flowing. 3. The control unit power supply circuit further includes a second capacitor for smoothing the supplied DC power, and a current limiting resistor for limiting an inrush current when charging the second capacitor. 2. The inverter device according to 2. 4. The inverter device according to claim 3, wherein the control unit power supply circuit further includes a backflow prevention diode for preventing backflow of current from the second capacitor. 5. A switching circuit for turning on / off the supplied DC power between the control unit power supply circuit and the inverter, wherein the DC power to the inverter is turned on / off. 5. The inverter device according to any one of 4. 6. An inverter device according to claim 1, further comprising: a converter that converts supplied AC power into DC power and supplies the DC power to the inverter device. And inverter system.