JP7452315B2 - power converter - Google Patents

Description

The present disclosure relates to a power conversion device.

Conventionally, in a power conversion device capable of both AC input and DC input, a configuration having a charging circuit for initial charging of a smoothing capacitor including a unidirectional switch (for example, a thyristor) and a charging resistor has been known. (See Patent Document 1).

In Patent Document 1, the positive side DC terminal of the DC input is connected to the anode side of the unidirectional switch, and a reversely connected diode is provided that is connected in parallel with the unidirectional switch. Thereby, it is possible to appropriately realize a regenerative operation by allowing the current in the regenerative state to pass through the reversely connected diode instead of the charging resistor, while allowing the charging circuit to function during DC input.

Patent No. 5323287 Public Relations

However, in Patent Document 1, since it is necessary to provide a reverse-connected diode, there is a possibility that the cost of the power conversion device increases or the size becomes relatively large.

Therefore, in view of the above-mentioned problems, it is an object of the present invention to provide a technique that can appropriately realize regenerative operation during DC input of a power conversion device with a simpler configuration.

To achieve the above object, in one embodiment of the present disclosure,
an AC input section that can receive AC power from the outside;
a rectifier circuit including a plurality of diodes and configured to be able to convert the AC power to DC power;
a positive line and a negative line, one end of which is connected to each of the positive output terminal and negative output terminal of the rectifier circuit;
a smoothing circuit that includes a smoothing capacitor provided in a path connecting the positive line and the negative line, and smoothes DC power of the positive line and the negative line;
an inverter circuit connected to the other ends of the positive line and the negative line and converting the DC power smoothed by the smoothing circuit into predetermined AC power and outputting the same;
A unidirectional switch that is provided on the positive line between the rectifier circuit and the smoothing circuit and that can flow a current in a power running state when closed, and a resistor that is connected in parallel with the switch. charging circuit;
a DC input section capable of receiving DC power from the outside, including a positive DC terminal drawn out from a portion of the positive line on the anode side as seen from the switch, and a negative DC terminal drawn out from the negative line; Prepare,
A cathode side portion of the positive line viewed from the switch and an input end of the rectifier circuit are connected or configured to be connectable;
A power conversion device is provided.

In other embodiments,
an AC input section that can receive AC power from the outside;
a rectifier circuit including a plurality of diodes and configured to be able to convert the AC power to DC power;
a positive line and a negative line, one end of which is connected to each of the positive output terminal and negative output terminal of the rectifier circuit;
a smoothing circuit that includes a smoothing capacitor and smoothes DC power on the positive line and the negative line;
an inverter circuit connected to the other ends of the positive line and the negative line and converting the DC power smoothed by the smoothing circuit into predetermined AC power and outputting the same;
A unidirectional switch that is provided on the negative line between the rectifier circuit and the smoothing circuit and that can flow a current in a power running state when closed, and a resistor that is connected in parallel with the switch. charging circuit;
a DC input section capable of receiving DC power from the outside, including a positive DC terminal drawn out from the positive line and a negative DC terminal drawn out from a cathode side portion of the negative line viewed from the switch; Prepare,
A portion of the negative line on the anode side viewed from the switch and an input end of the rectifier circuit are connected or configured to be connectable;
A power conversion device is provided.

According to the embodiments described above, it is possible to provide a technique that can appropriately realize regenerative operation during direct current input of a power conversion device with a simpler configuration.

FIG. 2 is a circuit diagram showing a first example of an inverter device. It is a circuit diagram showing a second example of an inverter device. It is a circuit diagram showing a third example of an inverter device. It is a circuit diagram showing a fourth example of an inverter device. It is a circuit diagram showing a fifth example of an inverter device. It is a circuit diagram showing a sixth example of an inverter device. It is a circuit diagram showing a seventh example of an inverter device. It is a circuit diagram showing an eighth example of an inverter device.

Embodiments will be described below with reference to the drawings.

[First example of inverter device]
With reference to FIG. 1, a first example of an inverter device 1 according to the present embodiment will be described.

<Inverter device configuration>
FIG. 1 is a circuit diagram showing a first example of an inverter device 1 according to the present embodiment.

The inverter device 1 (an example of a power conversion device) generates predetermined AC power (U-phase, V-phase, and W-phase AC power) from externally input AC power or DC power, and converts the external load. Output to device. The load device is, for example, an electric motor. In this example, a case will be mainly described in which three-phase AC power is generated from DC power input from the positive bus PL0 and negative bus NL0 of the external DC common bus L0 and output to an external load device. The same applies to second to eighth examples (FIGS. 2 to 8), which will be described later.

As shown in FIG. 1, the inverter device 1 includes an AC input section ACIN, a rectifier circuit 10, a smoothing circuit 20, an inverter circuit 30, an AC output section ACOUT, a charging circuit 40, and a DC input section DCIN. and a shorting conductor 50.

The AC input unit ACIN is used to input AC power from the outside. The AC input unit ACIN includes an AC input terminal R, an AC input terminal S, and an AC input terminal T that are connected to R-phase, S-phase, and T-phase input lines of an external AC power source, respectively.

The rectifier circuit 10 is configured to be able to rectify three-phase AC power of R phase, S phase, and T phase input from an AC input unit ACIN, and output DC power. Specifically, the rectifier circuit 10 has positive and negative output terminals connected to one end of the positive line PL and the negative line NL, respectively, and supplies DC power to the smoothing circuit 20 through the positive line PL and the negative line NL. It can be output.

In the rectifier circuit 10, six diodes D1 to D6 are bridge-connected. Specifically, the rectifier circuit 10 is a bridge type full-wave rectifier circuit in which a combination of upper and lower arms of diodes D1, D2, diodes D3, D4, and diodes D5, D6 are connected in parallel. Intermediate points R0, S0, T0 (all examples of input terminals) of diodes D1, D2, diodes D3, D4, and diodes D5, D6 (all are examples of input terminals) are connected to AC input terminals R, S, T, respectively. Thereby, when an AC power source is connected to the AC input unit ACIN, the rectifier circuit 10 can rectify the input three-phase AC power and output DC power through the positive line PL and the negative line NL. .

The smoothing circuit 20 suppresses pulsations in the DC power output from the rectifier circuit 10 and the DC power regenerated from the inverter circuit 30 and smooths them.

Smoothing circuit 20 includes a smoothing capacitor Cdc.

The smoothing capacitor Cdc is arranged in parallel with the rectifier circuit 10 and the inverter circuit 30 on a path connecting the positive line PL and the negative line NL. The smoothing capacitor Cdc smoothes the DC power output from the rectifier circuit 10, the DC power output (regenerated) from the inverter circuit 30, and the DC power input from the DC input unit DCIN while repeating charging and discharging as appropriate. .

There may be one smoothing capacitor Cdc. Further, a plurality of smoothing capacitors Cdc may be arranged, and a plurality of smoothing capacitors Cdc may be connected in parallel or in series between the positive line PL and the negative line NL. Further, the plurality of smoothing capacitors Cdc may be configured such that a plurality of series-connected bodies of two or more smoothing capacitors Cdc are connected in parallel between the positive line PL and the negative line NL. The same may apply to the second to eighth examples described below.

The inverter circuit 30 has its positive and negative input ends connected to the other ends of the positive line PL and the negative line NL. The inverter circuit 30 converts the DC power supplied from the smoothing circuit 20 through the positive line PL and the negative line NL into U-phase, V-phase, and converts into W-phase three-phase AC power and outputs it to an external load device. The semiconductor switching elements S1 to S6 may be, for example, IGBTs (Insulated Gate Bipolar Transistors) or MOSFETs (Metal-Oxide-Semiconductor Field-Effect Transistors) made of silicon (Si). Further, the semiconductor switching elements S1 to S6 may be semiconductor elements using a wide bandgap semiconductor such as silicon carbide (SiC) or gallium nitride (GaN), for example.

In the inverter circuit 30, combinations (switch legs) of upper and lower arms of semiconductor switching elements S1, S2, semiconductor switching elements S3, S4, and semiconductor switching elements S5, S6 are connected in parallel between a positive line PL and a negative line NL. It is constructed in such a way that it includes a bridge circuit. In the inverter circuit 30, the U phase and V Phase and W phase output lines are drawn out. Furthermore, freewheeling diodes are connected in parallel to each of the semiconductor switching elements S1 to S6.

The AC output unit ACOUT is connected to an external load device. The AC output unit ACOUT includes an AC output terminal U, an AC output terminal V, and Includes AC output terminal W.

The charging circuit 40 is provided on the positive line PL between the rectifier circuit 10 and the smoothing circuit 20 (smoothing capacitor Cdc). Charging circuit 40 includes a thyristor 41 and a charging resistor 42.

The thyristor 41 (an example of a unidirectional switch) is a semiconductor element that allows current to flow in only one direction when turned on (closed). In the positive line PL between the rectifier circuit 10 and the smoothing circuit 20, the thyristor 41 is arranged so that the anode is arranged on the rectifier circuit 10 side and the cathode is arranged on the smoothing circuit 20 side. The circuit 20 is arranged so that current flows toward the circuit 20.

A charging resistor 42 (an example of a resistor) is connected in parallel with the thyristor 41.

The charging circuit 40 is configured such that the current flowing through the positive line PL toward the smoothing circuit 20 passes through the thyristor 41 when the thyristor 41 is turned on, and passes through the charging resistor 42 when the thyristor 41 is turned off. functions. Thereby, when the inverter device 1 is started, the thyristor 41 is turned off to allow current to flow through the charging resistor 42, thereby preventing a relatively large inrush current that charges the smoothing capacitor Cdc. Then, when the smoothing capacitor Cdc is charged to a certain extent and the voltage between the positive line PL and the negative line NL becomes relatively high, the thyristor 41 is turned on, and the smoothing circuit 20 A current can flow towards.

The DC input unit DCIN is used to input DC power from the outside. In this example, the DC input unit DCIN is connected to the DC common bus L0 and can receive DC power from the DC common bus L0. The DC input unit DCIN includes a positive DC terminal P and a negative DC terminal N.

The positive side DC terminal P is drawn out from a portion of the positive line PL between the rectifier circuit 10 and the charging circuit 40 (thyristor 41). That is, the positive side DC terminal P is connected to the anode side portion of the thyristor 41 on the positive line PL inside the inverter device 1. In this example (FIG. 1), the positive side DC terminal P is connected to the positive bus bar PL0 outside the inverter device 1.

The negative side DC terminal N is drawn out from an arbitrary position on the negative line NL. In this example, the negative side DC terminal N is connected to a portion of the negative line NL between the smoothing circuit 20 (smoothing capacitor Cdc) and the inverter circuit 30 inside the inverter device 1.

The shorting conductor 50 connects the positive line PL between the charging circuit 40 (thyristor 41) and the inverter circuit 30 and the diodes D5 and D6 inside the inverter device 1 when DC power is input from the outside. and the intermediate point T0 between them. That is, the shorting conductor 50 connects between the cathode side portion of the thyristor 41 on the positive line PL and the input end of the T-phase AC power of the rectifier circuit 10. The shorting conductor 50 is configured such that its electrical resistance is sufficiently lower than the electrical resistance of the charging resistor 42.

For example, a connection portion to which the shorting conductor 50 can be attached and detached may be provided in advance between the cathode side portion of the thyristor 41 on the positive line PL and the intermediate point T0. That is, the inverter device 1 may be configured to be able to connect between the cathode side portion of the thyristor 41 on the positive line PL and the T-phase AC power input end of the rectifier circuit 10 using the short-circuit conductor 50. As a result, users who use the inverter device 1 with DC power input from the outside can install the shorting conductor 50, and users who use the inverter device 1 with AC power input from the outside can use a usage mode in which the shorting conductor 50 is omitted. Can be adopted. Therefore, the same inverter device 1 can be provided to users in a form that can be used for both AC input and DC input. The same may apply to the short circuit conductors 50 of the fourth example, fifth example, and eighth example described below.

Further, for example, the shorting conductor 50 may be attached in advance to the inverter device 1 used for DC input, and the shorting conductor 50 may not be attached to the inverter device 1 used for AC input. In other words, the inverter device 1, which is determined in advance to be used for DC input, connects the cathode side portion of the thyristor 41 in the positive line PL and the T-phase AC power input terminal of the rectifier circuit 10 by means of the short-circuit conductor 50. may be connected in advance. Thereby, it is possible to provide the inverter device 1 with specifications suitable for each of users who use it for DC input and users who use it for AC input, while keeping the configuration other than the shorting conductor 50 common. The same may apply to the short circuit conductors 50 of the fourth example, fifth example, and eighth example described below.

<Operation of inverter device>
Continuing with reference to FIG. 1, the operation of the inverter device 1 in the case of DC input will be described.

When the inverter device 1 is in a power running state (that is, a state in which the load device is driven by AC power supplied from the inverter device 1), current flows along the path indicated by the white arrow in the figure. Thereby, the current flowing from the DC common bus L0 (positive bus PL0) passes through the charging circuit 40. Therefore, in the inverter device 1, the connection position between the positive side DC terminal P and the positive line PL is provided on the anode side of the thyristor 41, so that the charging circuit 40 can be connected not only in the case of AC input but also in the case of DC input. can be made to work.

On the other hand, when the inverter device 1 is in a regenerative state (that is, a state in which regenerative power from the load device is returned to the DC common bus L0 through the inverter device 1), a regenerative current flows along the path indicated by the satin-finished arrow in the figure. Specifically, the regenerative current of the positive line PL flowing out from the inverter circuit 30 returns to the positive line PL from the output end of the rectifier circuit 10 via the short-circuit conductor 50, the intermediate point T0, and the diode D5, and becomes the positive DC current. The current flows from the terminal P to the DC common bus L0 (positive bus PL0). That is, the regenerative current of the positive line PL flowing out from the inverter circuit 30 does not flow through the charging circuit 40, but flows out to the DC common bus L0 (positive bus PL0) through a bypass path passing through the short-circuit conductor 50. This is because the thyristor 41 cannot pass the current flowing through the positive line PL toward the positive DC terminal P, and the charging resistor 42 has a relatively higher electrical resistance than the bypass path passing through the shorting conductor 50. be.

For example, when a regenerative current passes through the charging resistor 42, at least a portion of the regenerative power is consumed as thermal energy by the charging resistor 42, so the loss of regenerative power (regenerative energy) may become relatively large. There is sex.

In contrast, in this example, by attaching the shorting conductor 50 between the cathode side portion of the thyristor 41 on the positive line PL and the intermediate point T0, the charging circuit 40 is bypassed and the regenerative current is transferred to the DC common bus. It can be returned to L0. Therefore, the inverter device 1 can appropriately realize regenerative operation while suppressing loss of regenerative power.

Further, for example, the regenerative current can be prevented from passing through the charging circuit 40 by drawing out the positive DC terminal P from the cathode side portion of the thyristor 41 on the positive line. However, in this case, since the DC current input from the outside cannot pass through the charging circuit 40, the DC common bus L0 (positive bus PL0) and the positive DC terminal are connected separately from the charging circuit 40 for AC input of the inverter device 1. It becomes necessary to provide a charging circuit for DC input between the terminal and P. As a result, the size of the overall system for driving the load device becomes relatively large due to the space for placing the additional charging circuit, and the cost of the entire system for driving the load device increases due to the additional charging circuit. There is a possibility that

Furthermore, by providing a reversely connected diode as in Patent Document 1, the regenerative current can bypass the charging resistor 42 and flow through the reversely connected diode. However, in this case, it becomes necessary to provide a reversely connected diode inside the inverter device 1. Therefore, the size of the inverter device 1 may become relatively large due to the space for arranging the reversely connected diodes, or the cost of the inverter device 1 may increase due to the additional reversely connected diodes.

In contrast, in this example, by simply adding the shorting conductor 50, a bypass path using the rectifier circuit 10 for AC input can be realized. Therefore, the inverter device 1 can appropriately realize the regenerative operation at the time of DC input to the inverter device 1 with a simpler configuration. Therefore, the size of the entire system that drives the load device including the inverter device 1 can be kept relatively small. Moreover, the cost of the entire system that drives the load device including the inverter device 1 can be suppressed. Furthermore, the working time for manufacturing the entire system for driving a load device including the inverter device 1 can be relatively shortened.

[Second example of inverter device]
Next, with reference to FIG. 2, a second example of the inverter device 1 according to the present embodiment will be described. Hereinafter, the explanation will focus on the parts that are different from the above-mentioned first example, and the explanation about the same or corresponding contents as the above-mentioned first example may be simplified or omitted.

<Inverter device configuration>
FIG. 2 is a circuit diagram showing a second example of the inverter device 1 according to the present embodiment.

As shown in FIG. 2, the inverter device 1 includes an AC input section ACIN, a rectifier circuit 10, a smoothing circuit 20, an inverter circuit 30, an AC output section ACOUT, and a charging circuit, as in the case of the first example described above. It includes a circuit 40 and a direct current input section DCIN. Moreover, unlike the case of the above-mentioned first example, the inverter device 1 includes an external shorting terminal T1.

The external shorting terminal T1 (an example of an external connection terminal) is drawn out from the cathode side portion of the thyristor 41 on the positive line PL.

Thereby, outside of the inverter device 1, the shorting conductor 60 can connect between the AC input terminal R and the external shorting terminal T1. Like the shorting conductor 50 of the first example described above, the shorting conductor 60 is configured such that its electrical resistance is sufficiently lower than the electrical resistance of the charging resistor 42.

<Operation of inverter device>
Continuing with reference to FIG. 2, the operation of the inverter device 1 in the case of DC input will be described.

When the inverter device 1 is in the power running state, current flows along the path indicated by the white arrow in the figure, as in the first example described above. Thereby, the charging circuit 40 can function not only in the case of AC input but also in the case of DC input.

On the other hand, when the inverter device 1 is in a regenerative state, a regenerative current flows along the path indicated by the satin-finished arrow in the figure. Specifically, the regenerative current of the positive line PL flowing out from the inverter circuit 30 passes through the external shorting terminal T1, the shorting conductor 60, the AC input terminal R, the intermediate point R0, and the diode D1 to the output of the rectifier circuit 10. It returns to the positive line PL from the end and flows out from the positive side DC terminal P to the positive bus line PL0. That is, the regenerative current of the positive line PL flowing out from the inverter circuit 30 does not flow through the charging circuit 40, but flows out to the DC common bus L0 (positive bus PL0) through a bypass path passing through the short-circuit conductor 60. This is because the thyristor 41 cannot pass the current flowing through the positive line PL toward the positive DC terminal P, and the charging resistor 42 has a relatively higher electrical resistance than the bypass path passing through the short-circuit conductor 60. be.

Accordingly, in this example, by attaching the shorting conductor 60 between the external shorting terminal T1 and the AC input terminal R, the charging circuit 40 can be bypassed and the regenerative current can be returned to the DC common bus L0. Therefore, as in the case of the first example described above, the inverter device 1 can appropriately realize the regenerative operation while suppressing the loss of regenerative power.

Further, in this example, by simply adding the external shorting terminal T1 and attaching the shorting conductor 60 outside the inverter device 1, a bypass path using the rectifier circuit 10 for AC input can be realized. Therefore, as in the first example described above, the inverter device 1 can appropriately realize the regenerative operation at the time of DC input to the inverter device 1 with a simpler configuration. Therefore, the size of the entire system that drives the load device including the inverter device 1 can be kept relatively small. Moreover, the cost of the entire system that drives the load device including the inverter device 1 can be suppressed. Furthermore, the working time for manufacturing the entire system for driving a load device including the inverter device 1 can be relatively shortened.

[Third example of inverter device]
Next, a third example of the inverter device 1 according to the present embodiment will be described with reference to FIG. 3. Hereinafter, the explanation will focus on the parts that are different from the above-mentioned first example, etc., and the explanation about the same or corresponding contents as the above-mentioned first example etc. may be simplified or omitted.

<Inverter device configuration>
FIG. 3 is a circuit diagram showing a third example of the inverter device 1 according to the present embodiment.

As shown in FIG. 3, the inverter device 1 includes an AC input section ACIN, a rectifier circuit 10, a smoothing circuit 20, an inverter circuit 30, an AC output section ACOUT, as in the first example described above. It includes a charging circuit 40 and a direct current input section DCIN. Furthermore, unlike the first example described above, the inverter device 1 includes reactor connection terminals LT1 and LT2.

In this example, the positive line PL is divided between the charging circuit 40 (thyristor 41) and the smoothing capacitor Cdc into a positive line PL1 on the charging circuit 40 side and a positive line PL2 on the smoothing capacitor Cdc side.

Reactor connection terminals LT1 and LT2 are drawn out from the ends of the divided positive lines PL1 and PL2, respectively. Reactor connection terminals LT1 and LT2 are connected to both ends of the reactor Ldc outside the inverter device 1.

The reactor Ldc receives the DC power output from the rectifier circuit 10, the DC power output (regenerated) from the inverter circuit 30, and the DC input unit DCIN while appropriately generating voltage so as to prevent changes in current. Smooth DC power. Thereby, the smoothing circuit 20 includes the reactor Ldc in addition to the smoothing capacitor Cdc, and the DC power output from the rectifier circuit 10 or the DC power input from the DC common bus L0 or the inverter circuit 30 is output from the inverter circuit 30. DC power can be smoothed.

Furthermore, a shorting conductor 60 can be connected between the reactor connection terminal LT1 (an example of an external connection terminal) and the AC input terminal R. The shorting conductor 60 is configured such that its electrical resistance is sufficiently lower than the electrical resistance of the charging resistor 42, as in the second example described above.

<Operation of inverter device>
Continuing with reference to FIG. 3, the operation of the inverter device 1 in the case of DC input will be described.

When the inverter device 1 is in the power running state, current flows along the path indicated by the white arrow in the figure, as in the first example described above. Thereby, the charging circuit 40 can function not only in the case of AC input but also in the case of DC input.

On the other hand, when the inverter device 1 is in a regenerative state, a regenerative current flows along the path indicated by the satin-finished arrow in the figure. Specifically, the regenerative current of the positive line PL flowing out from the inverter circuit 30 passes through the reactor connection terminal LT1, the shorting conductor 60, the AC input terminal R, the intermediate point R0, and the diode D1, and then reaches the output terminal of the rectifier circuit 10. The current returns to the positive line PL and flows from the positive side DC terminal P to the positive bus line PL0. In other words, as in the case of the second example described above, the regenerative current of the positive line PL flowing out from the inverter circuit 30 does not flow through the charging circuit 40, but passes through the bypass path passing through the short-circuit conductor 60 to the DC common bus L0 (positive bus PL0). ).

Thereby, in this example, by attaching the short circuit conductor 60 between the reactor connection terminal LT1 and the AC input terminal R, the charging circuit 40 can be bypassed and the regenerative current can be returned to the DC common bus L0. Therefore, the inverter device 1 can appropriately realize regenerative operation in a manner that suppresses loss of regenerated power, as in the case of the above-mentioned first example and the like.

Further, in this example, by simply attaching the shorting conductor 60 outside the inverter device 1 using the reactor connection terminal LT1, a bypass path using the rectifier circuit 10 for AC input can be realized. Therefore, the inverter device 1 can appropriately realize the regenerative operation when direct current is input to the inverter device 1 with a simpler configuration, as in the case of the above-mentioned first example. Therefore, the size of the entire system that drives the load device including the inverter device 1 can be kept relatively small. Moreover, the cost of the entire system that drives the load device including the inverter device 1 can be suppressed. Furthermore, the working time for manufacturing the entire system for driving a load device including the inverter device 1 can be relatively shortened.

[Fourth example of inverter device]
Next, a fourth example of the inverter device 1 according to the present embodiment will be described with reference to FIG. 4. Hereinafter, the explanation will focus on the parts that are different from the above-mentioned first example, etc., and the explanation about the same or corresponding contents as the above-mentioned first example etc. may be simplified or omitted.

<Inverter device configuration>
FIG. 4 is a circuit diagram showing a fourth example of the inverter device 1 according to the present embodiment.

As shown in FIG. 4, the inverter device 1 includes an AC input section ACIN, a rectifier circuit 10, a smoothing circuit 20, an inverter circuit 30, an AC output section ACOUT, as in the first example described above. It includes a charging circuit 40 and a direct current input section DCIN. Further, the inverter device 1 includes a shorting conductor 50 as in the first example described above.

Shorting conductor 50 includes paths 50A, 50R, 50S, and 50T.

One end of the path 50A is connected to the cathode side portion of the thyristor 41 in the positive line PL, and the other end is connected to one end of the paths 50R, 50S, and 50T.

One end of the path 50R is connected to the other end of the path 50A, and the other end is connected to the intermediate point R0 between the diodes D1 and D2.

The path 50S has one end connected to the other end of the path 50A, and the other end connected to the intermediate point S0 between the diodes D3 and D4.

Path 50T has one end connected to the other end of path 50A, and the other end connected to intermediate point T0 between diodes D5 and D6.

That is, in the shorting conductor 50, a path 50A extends from the cathode side portion of the thyristor 41 in the positive line PL, and the tip branches into paths 50R, 50S, and 50T, which are connected to intermediate points R0, S0, and T0, respectively. It is configured in such a manner.

The shorting conductor 50 is configured such that the electrical resistance of each path passing through each of the paths 50R, 50S, and 50T from the path 50A is sufficiently lower than the electric resistance of the charging resistor 42.

<Operation of inverter device>
Continuing with reference to FIG. 4, the operation of the inverter device 1 in the case of DC input will be described.

When the inverter device 1 is in the power running state, current flows along the path indicated by the white arrow in the figure, as in the first example described above. Thereby, the charging circuit 40 can function not only in the case of AC input but also in the case of DC input.

On the other hand, when the inverter device 1 is in a regenerative state, a regenerative current flows along the path indicated by the satin-finished arrow in the figure. Specifically, the regenerative current of the positive line PL flowing out from the inverter circuit 30 branches from the path 50A to paths 50R, 50S, and 50T. Then, the regenerative current passes through the intermediate point R0 and the diode D1, the intermediate point S0 and the diode D3, and the intermediate point T0 and the diode D5, and joins together at the output end of the rectifier circuit 10, returns to the positive line PL, and returns to the positive line PL. It flows out from the side DC terminal P to the positive bus bar PL0. That is, the regenerative current of the positive line PL flowing out from the inverter circuit 30 does not flow through the charging circuit 40, but flows out to the DC common bus L0 (positive bus PL0) through a bypass path passing through the short-circuit conductor 50. This is because the thyristor 41 cannot pass the current flowing through the positive line PL toward the positive DC terminal P, and the charging resistor 42 has a relatively higher electrical resistance than the bypass path passing through the shorting conductor 50. be.

Accordingly, in this example, the charging circuit 40 is bypassed by attaching the shorting conductor 50 that connects the cathode side portion of the thyristor 41 on the positive line PL and each of the intermediate points R0, S0, and T0. Regenerative current can be returned to the DC common bus L0. Therefore, as in the case of the first example described above, the inverter device 1 can appropriately realize the regenerative operation while suppressing the loss of regenerative power. Further, in this example, since the bypass path is branched into three, a larger regenerative current can flow.

Further, in this example, as in the case of the first example described above, by simply adding the shorting conductor 50, a bypass path using the rectifier circuit 10 for AC input can be realized. Therefore, the inverter device 1 can appropriately realize the regenerative operation at the time of DC input to the inverter device 1 with a simpler configuration. Therefore, the size of the entire system that drives the load device including the inverter device 1 can be kept relatively small. Moreover, the cost of the entire system that drives the load device including the inverter device 1 can be suppressed. Furthermore, the working time for manufacturing the entire system for driving a load device including the inverter device 1 can be relatively shortened.

[Other examples of inverter devices]
Next, another example of the inverter device 1 according to this embodiment will be described.

The inverter devices 1 of the first to fourth examples described above may be modified or changed as appropriate.

For example, in the first to fourth examples described above, instead of the thyristor 41, a GTO (Gate Turn-Off thyristor) (an example of a unidirectional switch) may be used. In this case as well, similar actions and effects can be achieved.

Further, for example, in the above-described first example and its modified examples, one end of the short-circuiting conductor 50 may be connected to the intermediate point R0 or the intermediate point S0 instead of the intermediate point T0. In this case as well, similar actions and effects can be achieved.

Further, for example, in the above-mentioned second and third examples and their modifications, one end of the shorting conductor 60 may be connected to the AC input terminal S or the AC input terminal T instead of the AC input terminal R. . In this case as well, similar actions and effects can be achieved.

Further, for example, in the above-described third example and its modified example, the reactor Ldc may be omitted. In this case, a shorting conductor connecting the positive lines PL1 and PL2 is connected between the reactor connection terminals LT1 and LT2. Further, in this case, the other end of the shorting conductor 60 may be connected to a reactor connection terminal LT2 (an example of an external connection terminal) instead of the reactor connection terminal LT1. In this case as well, similar actions and effects can be achieved.

Furthermore, for example, in the above-described fourth example and its modifications, any one of the paths 50R, 50S, and 50T of the short-circuiting conductor 50 may be omitted. In other words, even if the shorting conductor 50 branches into two from the path 50A toward the input ends of any two of the R phase, S phase, and T phase, and each is connected to the two input ends. good. In this case as well, similar actions and effects can be achieved.

Further, for example, in the above-mentioned second and third examples and their modifications, the short-circuit conductor 60 has the other end bifurcated or three-branched like the short-circuit conductor 50 of the above-mentioned fourth example and its modifications. However, it may be connected to at least two of the AC input terminals R, S, and T. Thereby, the same operation and effect as in the case of the above-mentioned fourth example can be achieved.

Further, for example, in the first to fourth examples and their modifications, the charging circuit 40 connects the rectifier circuit 10 and the smoothing circuit 20 (smoothing capacitor Cdc) on the negative line NL instead of the positive line PL. It may be provided in between.

For example, FIGS. 5 to 8 are circuit diagrams showing fifth to eighth examples of the inverter device 1 according to the present embodiment. Specifically, in FIGS. 5 to 8, the charging circuit 40 of the inverter device 1 of the above-mentioned first to fourth examples (FIGS. 1 to 4) is connected to the negative line NL instead of the positive line PL. This corresponds to a circuit diagram showing a specific example of the arrangement.

As shown in FIGS. 5 to 8, the thyristor 41 and the GTO are arranged such that the anode is arranged on the smoothing circuit 20 side and the cathode is arranged on the rectifier circuit 10 side, that is, when turned on, the thyristor 41 and the GTO are arranged toward the rectifier circuit 10 from the smoothing circuit 20. It is placed on the negative line NL so that current flows therethrough. Further, the positive side DC terminal P is drawn out from an arbitrary position on the positive line PL, and the negative side DC terminal N is drawn out from the part of the negative line NL between the rectifier circuit 10 and the charging circuit 40, that is, on the negative line NL. It is drawn out from the cathode side of the thyristor 41 and the GTO. As a result, the charging circuit 40 can function not only in the case of AC input but also in the case of DC input, as in the first to fourth examples and their modifications described above (FIGS. 5 to 5). (See the white arrow in 8).

Further, as shown in FIGS. 5 and 8, in the first example, the fourth example, and their modifications, the shorting conductor 50 connects the anode side portion of the thyristor 41 and GTO in the negative line NL and the rectifier circuit. At least one of the 10 input terminals (intermediate points R0, S0, T0) is connected. Thereby, when the inverter device 1 is in the regenerative state, the current flowing from the negative side DC terminal N can bypass the charging circuit 40 by passing through at least one of the diodes D2, D4, and D6 and the shorting conductor 50. (See the satin-finished arrows in Figures 5 and 8). Therefore, similar actions and effects can be achieved.

Moreover, as shown in FIG. 6, in the above-mentioned second example and its modification, the external shorting terminal T1 is drawn out from the anode side portion of the thyristor 41 and GTO on the negative line NL. As a result, when the inverter device 1 is in the regenerative state, the current flowing from the negative side DC terminal N charges while passing through at least one of the diodes D2, D4, and D6, the shorting conductor 60, and the external shorting terminal T1. The circuit 40 can be bypassed (see the satin arrow in FIG. 6). Therefore, similar actions and effects can be achieved.

Further, as shown in FIG. 7, in the third example and its modifications, the reactor connection terminals LT1 and LT2 are connected between the charging circuit 40 and the smoothing capacitor Cdc instead of being drawn out from the positive lines PL1 and PL2. The negative line NL is pulled out from each tip (the tips of the negative lines NL1 and NL2) in a divided manner. As a result, when the inverter device 1 is in the regenerative state, the current flowing from the negative side DC terminal N passes through at least one of the diodes D2, D4, and D6, the shorting conductor 60, and either the reactor connection terminal LT1 or LT2. The charging circuit 40 can be bypassed in this way (see the satin-finished arrow in FIG. 7). Therefore, similar actions and effects can be achieved.

[Effect]
Next, the operation of the inverter device 1 according to this embodiment will be summarized.

In this embodiment, the AC input unit ACIN is configured to be able to receive AC power from the outside. Further, the rectifier circuit 10 includes diodes D1 to D6, and is configured to be able to convert AC power into DC power. Further, one end of the positive line PL and the negative line NL is connected to each of the positive side output terminal and the negative side output terminal of the rectifier circuit 10. Further, the smoothing circuit 20 includes a smoothing capacitor Cdc provided in a path connecting the positive line PL and the negative line NL, and smoothes the DC power of the positive line PL and the negative line NL. Further, the inverter circuit 30 is connected to the other ends of the positive line PL and the negative line NL, converts the DC power smoothed by the smoothing circuit 20 into predetermined AC power, and outputs the same. The charging circuit 40 is provided on the positive line PL between the rectifier circuit 10 and the smoothing circuit 20, and is a unidirectional switch (for example, a thyristor 41 or a GTO ) and a charging resistor 42 connected in parallel with the unidirectional switch. The DC input unit DCIN includes a positive DC terminal P drawn out from the anode side portion of the positive line PL as seen from the unidirectional switch, and a negative DC terminal N drawn out from the negative line NL. It is configured to be able to receive DC power from. The cathode side portion of the positive line PL viewed from the unidirectional switch and the input end of the rectifier circuit 10 are connected or are configured to be connectable. Specifically, the rectifier circuit 10 ( The cathode side portion of the positive line PL viewed from the unidirectional switch and the input end of the rectifier circuit 10 are connected so that the electrical resistance of the path passing through the diodes D1, D3, D5) is small. or is configured to be connectable.

Thereby, when the inverter device 1 is in the power running state, the charging circuit 40 can be operated not only when the AC input is applied but also when the DC input is applied. In addition, when the inverter device 1 is in a regenerative state, the unidirectionality of the positive line PL is transmitted from the cathode side part as seen from the unidirectional switch of the positive line PL via the rectifier circuit 10 (diodes D1, D3, D5). The regenerative current can be bypassed to the part on the anode side seen from the switch. Therefore, the inverter device 1 can appropriately realize regenerative operation during DC input with a simpler configuration.

Further, in this embodiment, inside the device (inverter device 1), the cathode side portion of the positive line PL viewed from the switch and the input end of the rectifier circuit 10 are connected or can be connected. It may be configured as follows.

Thereby, it is possible to provide a specific configuration that can appropriately realize the regenerative operation during DC input of the inverter device 1 with a simpler configuration.

Further, in this embodiment, external connection terminals (for example, external shorting terminal T1 and reactor connection terminals LT1 and LT2) may be provided which are drawn out from the cathode side portion of the positive line PL when viewed from the unidirectional switch. .

As a result, the external connection terminal corresponding to the cathode side portion as seen from the unidirectional switch of the positive line PL, and the AC input section ACIN (AC input terminals R, S, T) corresponding to the input end of the rectifier circuit 10. The short-circuit conductor 60 can be used to connect between the two terminals. Therefore, it is possible to provide a specific configuration that can appropriately realize the regenerative operation of the inverter device 1 during DC input with a simpler configuration.

In addition, in this embodiment, the cathode side portion of the positive line PL viewed from the unidirectional switch is divided, and both ends of the reactor Ldc as a component of the smoothing circuit 20 are pulled out so that they can be connected externally. Reactor connection terminals LT1 and LT2 may be provided. The above external connection terminal may be either one of the reactor connection terminals LT1 and LT2.

As a result, the cathode side portion of the positive line PL viewed from the unidirectional switch and the input end of the rectifier circuit 10 can be connected by using the existing reactor connection terminals LT1 and LT2. Can be done. Therefore, it is possible to provide a specific configuration that can appropriately realize the regenerative operation during DC input of the inverter device 1 with a simpler configuration.

In addition, in this embodiment, the cathode side portion of the positive line PL viewed from the unidirectional switch and the plurality of input terminals (intermediate points R0, S0, T0) corresponding to the plurality of phases of AC power of the rectifier circuit 10 It may be connected to at least two of them, or may be configured to be connectable.

This allows a relatively large regenerative current to flow when the inverter device 1 is in the regenerative state.

Further, in this embodiment, the AC input unit ACIN is configured to be able to receive AC power from the outside. Further, the rectifier circuit 10 includes diodes D1 to D6, and is configured to be able to convert AC power into DC power. Further, one end of the positive line PL and the negative line NL is connected to each of the positive side output terminal and the negative side output terminal of the rectifier circuit 10. Further, the smoothing circuit 20 includes a smoothing capacitor Cdc, and smoothes the DC power of the positive line PL and the negative line NL. Further, the inverter circuit 30 is connected to the other ends of the positive line PL and the negative line NL, converts the DC power smoothed by the smoothing circuit 20 into predetermined AC power, and outputs the same. Further, the charging circuit 40 is provided on the negative line NL between the rectifying circuit 10 and the smoothing circuit 20, and includes a unidirectional switch that can flow current in a power running state when closed, and a unidirectional switch. and a charging resistor 42 connected in parallel. Further, the DC input unit DCIN includes a positive side DC terminal P drawn out from the positive line PL, and a negative side DC terminal N drawn out from the cathode side portion of the negative line NL viewed from the unidirectional switch. It is configured to be able to receive DC power from. The anode side portion of the negative line NL viewed from the unidirectional switch and the input end of the rectifier circuit 10 are connected or are configured to be connectable.

Thereby, when the inverter device 1 is in the power running state, the charging circuit 40 can be operated not only when the AC input is applied but also when the DC input is applied. When the inverter device 1 is in a regenerative state, the cathode side seen from the unidirectional switch of the negative line NL passes through the rectifier circuit 10 (diodes D2, D4, D6), and then seen from the switch of the negative line NL. The regenerative current can be bypassed to the anode side portion. Therefore, the inverter device 1 can appropriately realize regenerative operation during DC input with a simpler configuration.

Although the embodiments have been described in detail above, the present disclosure is not limited to such specific embodiments, and various modifications and changes can be made within the scope of the gist described in the claims.

1 Inverter device (power conversion device)
10 Rectifier circuit 20 Smoothing circuit 30 Inverter circuit 40 Charging circuit 41 Thyristor (unidirectional switch)
42 Charging resistance (resistor)
50, 60 Short circuit conductor 50A, 50R, 50S, 50T Path ACIN AC input section ACOUT AC output section Cdc Smoothing capacitor D1 to D6 Diode DCIN DC input section L0 DC common bus Ldc Reactor LT1, LT2 Reactor connection terminal (external connection terminal)
N Negative DC terminal NL, NL1, NL2 Negative line NL0 Negative bus P Positive DC terminal PL, PL1, PL2 Positive line PL0 Positive bus R, S, T AC input terminal R0, S0, T0 Intermediate point (input end)
S1 to S6 Semiconductor switching element T1 External short circuit terminal (external connection terminal)
U, V, W AC output terminal U1, V1, W1 Intermediate point

Claims (7)

an AC input section that can receive AC power from the outside;
a rectifier circuit including a plurality of diodes and configured to be able to convert the AC power to DC power;
a positive line and a negative line, one end of which is connected to each of the positive output terminal and negative output terminal of the rectifier circuit;
a smoothing circuit that includes a smoothing capacitor provided in a path connecting the positive line and the negative line, and smoothes DC power of the positive line and the negative line;
an inverter circuit that is connected to the other ends of the positive line and the negative line and converts the DC power smoothed by the smoothing circuit into predetermined AC power and outputs the same;
A unidirectional switch that is provided on the positive line between the rectifier circuit and the smoothing circuit and that can flow a current in a power running state when closed, and a resistor that is connected in parallel with the switch. charging circuit;
a DC input section capable of receiving DC power from the outside, including a positive DC terminal drawn out from a portion of the positive line on the anode side as seen from the switch, and a negative DC terminal drawn out from the negative line; Prepare,
A cathode side portion of the positive line viewed from the switch and an input end of the rectifier circuit are connected or configured to be connectable;
Power converter. Among the paths between the cathode side portion of the positive line viewed from the switch and the positive DC terminal, the electrical resistance of the path passing through the rectifier circuit is lower than the electric resistance of the path passing through the resistor. A portion of the positive line on the cathode side viewed from the switch and an input end of the rectifier circuit are connected or configured to be connectable.
The power conversion device according to claim 1. A cathode-side portion of the positive line viewed from the switch and an input end of the rectifier circuit are connected or configured to be connectable within the device;
The power conversion device according to claim 1 or 2. an external connection terminal drawn out from a cathode side portion of the positive line viewed from the switch;
The power conversion device according to claim 1 or 2. A cathode side portion of the positive line viewed from the switch is divided, and two reactor connection terminals are provided that are pulled out so that both ends of the reactor as a component of the smoothing circuit can be connected externally,
The external connection terminal is one of the two reactor connection terminals,
The power conversion device according to claim 4. connected or configured to be connectable to a cathode side portion of the positive line viewed from the switch and at least two of the plurality of input terminals corresponding to the plurality of phases of AC power of the rectifier circuit;
The power conversion device according to any one of claims 1 to 5. an AC input section that can receive AC power from the outside;
a rectifier circuit including a plurality of diodes and configured to be able to convert the AC power to DC power;
a positive line and a negative line, one end of which is connected to each of the positive output terminal and negative output terminal of the rectifier circuit;
a smoothing circuit that includes a smoothing capacitor and smoothes DC power on the positive line and the negative line;
an inverter circuit connected to the other ends of the positive line and the negative line and converting the DC power smoothed by the smoothing circuit into predetermined AC power and outputting the same;
A unidirectional switch that is provided on the negative line between the rectifier circuit and the smoothing circuit and that can flow a current in a power running state when closed, and a resistor that is connected in parallel with the switch. charging circuit;
a DC input section capable of receiving DC power from the outside, including a positive DC terminal drawn out from the positive line and a negative DC terminal drawn out from a cathode side portion of the negative line viewed from the switch; Prepare,
A portion of the negative line on the anode side viewed from the switch and an input end of the rectifier circuit are connected or configured to be connectable;
Power converter.

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