Power conversion device and motor drive device having two DC voltage modes

Abstract

The present invention provides a power conversion device and a motor drive device having two DC voltage modes. The power conversion device (1) includes: an inverter unit (11) that converts an input DC voltage into an AC voltage and outputs it; a first capacitor bank (12) whose positive electrode is connected to the positive electrode of the DC input side of the inverter unit (11); a second capacitor bank (13) whose negative electrode is connected to the negative electrode of the DC input side of the inverter unit (11); a first terminal portion (14) that is connected to the positive electrode of the first capacitor bank (12); a second terminal portion (15) that is connected to the negative electrode of the first capacitor bank (12); a third terminal portion (16) that is connected to the positive electrode of the second capacitor bank (13); and a fourth terminal portion (17) that is connected to the negative electrode of the second capacitor bank (13), and the distance between the first terminal portion (14) and the third terminal portion (16) is substantially the same as the distance between the second terminal portion (15) and the fourth terminal portion (17).

Description

Technical Field

[0001] The present invention relates to a power conversion device having two direct current voltage modes and a motor drive device. Background Art

[0002] In a motor drive device that controls the drive of a motor in a machine tool, a forging machine, an injection molding machine, an industrial machine, or various robots, a rectifier (converter) is used to convert an AC voltage input from an AC power source into a DC voltage and output it to a DC link, and an inverter is used to convert the DC voltage in the DC link into an AC voltage, and the AC voltage is supplied as a drive voltage to the motor provided on each drive shaft. A "DC link" refers to a circuit portion that electrically connects the DC output side of a rectifier and the DC input side of an inverter, and sometimes a "DC link" is also referred to as a "DC link portion", "DC link", "DC link portion", "DC bus" or "DC intermediate circuit".

[0003] A capacitor is provided in the DC link, and the capacitor has the function of suppressing the pulsation component of the DC output of the rectifier and the function of accumulating DC power. Such a capacitor is also called a smoothing capacitor or a DC link capacitor. The more DC power that can be accumulated in the DC link, the more driving power the inverter can supply to the motor, and the degree of freedom of motor control increases. Therefore, as a capacitor provided in the DC link, a single large-capacity capacitor or a capacitor obtained by connecting a plurality of capacitors in parallel is used.

[0004] Electrolytic capacitors are widely used as capacitors in DC links. They have the advantage of ensuring a large capacity with a small volume, but also have the disadvantage of low withstand voltage. Therefore, in order to withstand the high DC voltage in the DC link, multiple capacitors are connected in series or a capacitor bank formed by connecting multiple capacitors in parallel is connected in series.

[0005] For example, in motor drive devices used in areas with higher AC power supply voltages such as the United States and Europe, the DC voltage rectified by the rectifier, that is, the DC voltage applied to the capacitors in the DC link, also increases (for example, 400 [V]). In this case, in many cases, multiple capacitors are connected in series so that the voltage applied to each capacitor does not exceed the withstand voltage. On the other hand, since the DC voltage applied to the capacitors in the DC link is also reduced (for example, 200 [V]) in motor drive devices used in areas with lower AC power supply voltages, there are cases where the withstand voltage of the capacitors is not exceeded. In this case, there is no need to connect multiple DC link capacitors in series.

[0006] Thus, since the configurations of the DC input sides (i.e., DC links) of the inverters in the motor drive devices required in low AC power voltage regions and high AC power voltage regions are different, it is necessary to separately fabricate multiple types of inverters. Therefore, there is a problem of a relatively large number of components. Thus, when manufacturing a motor drive device, by arranging two capacitor banks each composed of a plurality of capacitors connected in parallel and using a switching component to selectively switch the connection relationship between these two capacitor banks, it is possible to manufacture a motor drive device corresponding to the region to be shipped at low cost and with high efficiency. For example, when manufacturing a motor drive device to be shipped to a high AC power voltage region, the switching component is used to connect the two capacitor banks in series, and when manufacturing a motor drive device to be shipped to a low AC power voltage region, the switching component is used to connect the two capacitor banks in parallel.

[0007] As described in Japanese Patent Application Laid-Open No. 2004-358543, an arc application equipment power supply device is known, which is formed by a DC generation unit and a switching unit that switches the DC voltage of the input sides of the inverters corresponding to two types of received power voltage systems. The DC generation unit is formed by the following components: an input rectifier for rectifying the AC applied to its input terminal, a first inverter and a second inverter connected to the output side of the input rectifier, high-frequency transformers connected to the output sides of these inverters respectively, and an output rectifier connected to the output side of the high-frequency transformers. This arc application equipment power supply device is provided with a voltage balance control unit that freely performs series / parallel switching through the part connecting the output terminal of the input rectifier and the input terminal of the inverter to supply a predetermined DC voltage to the input terminal of the inverter, and suppresses the imbalance of voltage sharing between the voltage at the input terminal of the first inverter and the voltage at the input terminal of the second inverter during series connection.

[0008] As described in Japanese Patent Application Laid-Open No. 5-38061, a charging circuit device is known, which charges a battery using the power converted by an input power circuit formed with a wiring pattern on a substrate. In this charging circuit device, the input power circuit forms a full-wave rectifier circuit or a half-wave rectifier circuit by installing jumper components between a pad corresponding to a component between pads and a pad without a corresponding component on a wiring pattern formed with a wiring part shared by the full-wave rectifier circuit wiring and the half-wave rectifier circuit wiring as a pad.

[0009] As described in Japanese Utility Model Laid-Open No. 5-23795, a power supply device is known. It is an inverter-structured power supply device that operates with two types of AC power sources, low voltage and high voltage, as input power sources by switching internal connections. This power supply device includes: an input rectifier that rectifies the above input power source; first and second smoothing capacitors, one end of each of the first and second smoothing capacitors is connected to the positive and negative output terminals of the above input rectifier respectively; a connection switcher that, when the above input power source is low voltage, connects the other ends of the two smoothing capacitors to the negative and positive output terminals of the above input rectifier respectively, and when the above input power source is high voltage, connects the other ends of the two smoothing capacitors directly; two inverter switching elements that are connected in series between the positive and negative output terminals of the above input rectifier and switch alternately; two DC cut-off and inverter power supply capacitors that are connected in series between the positive and negative output terminals of the above input rectifier; and an output transformer that has a primary winding provided between the connection points of the two switching elements and the connection points of the two DC cut-off and inverter power supply capacitors, and a load is connected to the secondary winding.

[0010] As described in Japanese Patent Laid-Open No. 2005-243742, a printed circuit board is known. It includes: a plurality of wiring portions that include at least a pair of opposed electrodes constituting a capacitor and terminals connected to the electrodes; and a switching portion for selectively switching the connections between the terminals of the above wiring portions, and a predetermined capacitor capacitance is formed by the selective connection between the terminals by using the above switching portion.

[0011] As described in Japanese Utility Model Laid-Open No. 10-295081, a voltage dividing circuit of a series capacitor body is known. It is configured as follows: the collector of an NPN transistor is connected to the positive electrode of a first capacitor via a first resistor, the emitter of the NPN transistor is connected to the negative electrode of the first capacitor, a second resistor is connected between the positive electrode of the first capacitor and the base of the NPN transistor, the collector of a PNP transistor is connected to the negative electrode of a second capacitor via a third resistor, the emitter of the PNP transistor is connected to the positive electrode of the second capacitor, a fourth resistor is connected between the negative electrode of the second capacitor and the base of the PNP transistor, the emitter of the NPN transistor is connected to the emitter of the PNP transistor, and the base of the NPN transistor is connected to the base of the PNP transistor. Summary of the Invention

[0012] Regarding a switching component that is used to manufacture a motor drive device for low and high AC power supply voltages and switches the connection relationship of two capacitor banks composed of a plurality of capacitors connected in parallel, since a large current flows through it, it is mostly composed of a bus bar. The bus bar is made of a metal such as copper, brass, or aluminum, for example, and is manufactured by sheet metal processing. However, regarding sheet metal processing, the cost of the metal mold is high, and as a result, the manufacturing cost of the motor drive device increases. In addition, since switching components must be prepared separately for low and high AC power supply voltages, it is necessary to ensure the inventory of various switching components during manufacturing, and the manufacturing management is complicated. Therefore, a power conversion device and a motor drive device that can handle low and high AC power supply voltages and are easy to manufacture and have low costs are desired.

[0013] A power conversion device according to one aspect of the present invention includes: an inverter unit that converts an input DC voltage into an AC voltage and outputs it; a first capacitor bank composed of one or a plurality of capacitors connected in parallel, the positive electrode of the first capacitor bank being electrically connected to the positive electrode of the DC input side of the inverter unit; a second capacitor bank composed of one or a plurality of capacitors connected in parallel, the negative electrode of the second capacitor bank being electrically connected to the negative electrode of the DC input side of the inverter unit; a first terminal portion that is electrically connected to the positive electrode of the first capacitor bank; a second terminal portion that is electrically connected to the negative electrode of the first capacitor bank; a third terminal portion that is electrically connected to the positive electrode of the second capacitor bank; and a fourth terminal portion that is electrically connected to the negative electrode of the second capacitor bank, the distance between the first terminal portion and the third terminal portion being substantially the same as the distance between the second terminal portion and the fourth terminal portion.

[0014] In addition, a motor drive device according to one aspect of the present invention includes: a rectifier that converts AC power input from an AC power supply into a DC voltage and outputs it; and the above-mentioned power conversion device that is connected to the rectifier and converts the DC voltage input from the rectifier into an AC voltage for driving a motor and outputs it. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] The present invention should be more clearly understood by referring to the following drawings.

[0016] Figure 1A It is a view showing a power conversion device according to a first embodiment of the present invention and is a front view illustrating the arrangement of the first to fourth terminal portions in the power conversion device.

[0017] Figure 1B It is a view showing a power conversion device according to a first embodiment of the present invention and is a circuit diagram of the power conversion device.

[0018] Figure 2AIt is a cross-sectional view illustrating the first to fourth terminal portions formed by pads in through holes.

[0019] Figure 2B It is a front view illustrating the first to fourth terminal portions formed by pads in through holes.

[0020] Figure 3A It is a diagram showing a power conversion device in the low DC voltage mode of the first embodiment of the present invention, and is a front view showing an example of the arrangement of the first and second conductors.

[0021] Figure 3B It is a circuit diagram of the power conversion device in the low DC voltage mode of the first embodiment of the present invention.

[0022] Figure 4A It is a diagram showing a power conversion device in the high DC voltage mode of the first embodiment of the present invention, and is a front view showing an example of the arrangement of the third conductor.

[0023] Figure 4B It is a circuit diagram of the power conversion device in the high DC voltage mode of the first embodiment of the present invention.

[0024] Figure 5 It is an external view illustrating the power conversion device of the first embodiment of the present invention.

[0025] Figure 6 It is a diagram showing a motor drive device including the power conversion devices of the first to fourth embodiments of the present invention.

[0026] Figure 7A It is a diagram showing the power conversion device of the second embodiment of the present invention, and is a front view illustrating the arrangement of the first to fourth terminal portions inside the power conversion device.

[0027] Figure 7B It is a circuit diagram of the power conversion device of the second embodiment of the present invention.

[0028] Figure 8A It is a front view showing an example of the arrangement of the first to third conductors in the power conversion device of the second embodiment of the present invention, and shows an example of the arrangement of the first to third conductors in the low DC voltage mode.

[0029] Figure 8B It is a front view showing an example of the arrangement of the first to third conductors in the power conversion device of the second embodiment of the present invention, and shows an example of the arrangement of the first to third conductors in the high DC voltage mode.

[0030] Figure 9AIt is a circuit diagram of the power conversion device according to the third embodiment of the present invention, and shows the power conversion device when no electrical conductor is connected.

[0031] Figure 9B It is a circuit diagram of the power conversion device according to the third embodiment of the present invention, and shows the power conversion device in the low DC voltage mode.

[0032] Figure 9C It is a circuit diagram of the power conversion device according to the third embodiment of the present invention, and shows the power conversion device in the high DC voltage mode.

[0033] Figure 10 It is a circuit diagram of the power conversion device according to the fourth embodiment of the present invention.

[0034] Figure 11 It is a flowchart showing the inspection process when manufacturing the power conversion device according to the fourth embodiment of the present invention.

[0035] Figure 12 It is a flowchart showing a modified example of the inspection process when manufacturing the power conversion device according to the fourth embodiment of the present invention. Detailed Embodiments

[0036] Hereinafter, a power conversion device and a motor drive device having two DC voltage modes will be described with reference to the drawings. For easy understanding, the scales of these drawings are appropriately changed. The modes shown in the drawings are an example for implementation and are not limited to the illustrated embodiments. In addition, for the sake of simplicity of description, regarding the expression of "electrically connecting" each element, it is sometimes only denoted as "connecting".

[0037] Figure 1A It is a view showing the power conversion device according to the first embodiment of the present invention, and is a front view illustrating the arrangement of the first to fourth terminal portions in the power conversion device. Figure 1B It is a view showing the power conversion device according to the first embodiment of the present invention, and is a circuit diagram of the power conversion device. Hereinafter, parts denoted by the same reference numerals in different drawings represent constituent elements having the same function.

[0038] The power conversion device 1 according to the first embodiment of the present invention includes: an inverter section 11, a first capacitor bank 12, a second capacitor bank 13, a first terminal portion 14, second terminal portions 15 and 15', third terminal portions 16 and 16', a fourth terminal portion 17, a first resistor 18, and a second resistor 19. In addition, the power conversion device 1 has a positive DC terminal 41 and a negative DC terminal 42 on the DC input side.

[0039] The inverter unit 11 converts the input DC voltage into an AC voltage and outputs it. That is, the inverter unit 11 controls the conduction and cutoff of each switching element based on the switching instruction received from the inverter control unit (not shown), thereby converting the DC voltage between the positive and negative poles on the DC side applied to the inverter unit 11 into an AC voltage, and outputting this AC voltage between the terminals on the AC side of the inverter unit 11. Additionally, the inverter unit 11 can also control the conduction and cutoff of each switching element based on the switching instruction received from the inverter control unit, thereby converting the AC voltage between the terminals on the AC side applied to the inverter unit 11 into a DC voltage, and outputting this DC voltage between the positive and negative poles on the DC side of the inverter unit 11.

[0040] The inverter control unit (not shown) can be constructed, for example, in the form of a software program, or can also be constructed by a combination of various electronic circuits and software programs. For example, when constructed in the form of a software program, by causing an arithmetic processing device such as a DSP or FPGA to operate according to this software program, the functions of the above-mentioned respective parts can be realized. Alternatively, the inverter control unit can also be implemented as a semiconductor integrated circuit in which a software program for realizing the functions of each part is written. Additionally, the inverter control unit can also be provided, for example, in the numerical control device of a machine tool.

[0041] The inverter unit 11 is composed of a bridge circuit of switching elements and diodes connected in anti-parallel with these switching elements. When the load connected to the AC side of the inverter unit 11 is a three-phase electrical device, it is configured as a three-phase bridge circuit in order to output a three-phase AC voltage, and when the load connected to the AC side of the inverter unit 11 is a single-phase electrical device, it is configured as a single-phase bridge circuit in order to output a single-phase AC voltage. As an example of the load connected to the AC side of the inverter unit 11, there are motors and the like. As an example of the switching elements constituting the bridge circuit of the inverter unit 11, there are IGBTs, thyristors, GTOs, transistors, etc., but the type of the switching element itself does not limit this embodiment, and other switching elements can also be used.

[0042] A first capacitor bank 12 and a second capacitor bank 13 are connected to the positive and negative poles on the DC side of the inverter unit 11.

[0043] The first capacitor bank 12 is composed of one or a plurality of capacitors connected in parallel with each other. The positive pole of the first capacitor bank 12 is electrically connected to the positive pole on the DC input side of the inverter unit 11.

[0044] The second capacitor bank 13 is composed of one or a plurality of capacitors connected in parallel with each other. The negative pole of the second capacitor bank 13 is electrically connected to the negative pole on the DC input side of the inverter unit 11.

[0045] The first capacitor bank 12 and the second capacitor bank 13 have the function of storing the DC power for the AC voltage output by the inverter unit 11, and have the function of suppressing the pulsating components of the DC output of the rectifier ( Figure 1A and Figure 1B not shown) when a rectifier is provided on the DC side of the power conversion device 1. Each capacitor constituting the first capacitor bank 12 and the second capacitor bank 13 is, for example, an electrolytic capacitor, but as an alternative example, it may also be a film capacitor or the like.

[0046] In addition, the number of capacitors constituting the first capacitor bank 12 and the second capacitor bank 13 does not particularly limit this embodiment. In Figure 1A and Figure 1B , as an example, a case is shown where the first capacitor bank 12 and the second capacitor bank 13 are each configured to be connected in parallel with 4 capacitors. When the first capacitor bank 12 and the second capacitor bank 13 are each constituted by 1 capacitor, for example, it may be constituted by a single large-capacity capacitor.

[0047] The first resistor 18 is electrically connected in parallel with the first capacitor bank 12, and one end of the first resistor 18 is electrically connected to the first terminal portion 14 described later.

[0048] The second resistor 19 is electrically connected in parallel with the second capacitor bank 13, and one end of the second resistor 19 is electrically connected to the fourth terminal portion 17.

[0049] The first resistor 18 and the second resistor 19 have the function of voltage dividing resistors for preventing voltage imbalance applied to the first capacitor bank 12 and the second capacitor bank 13, respectively, in the high DC voltage mode described later. Therefore, the resistance values of the first resistor 18 and the second resistor 19 are set to the same magnitude.

[0050] When manufacturing the power conversion device 1, whether the first capacitor bank 12 and the second capacitor bank 13 are connected in parallel or in series is determined by the relationship between the withstand voltage of each capacitor in the first capacitor bank 12 and the second capacitor bank 13 and the magnitude of the DC link voltage on the DC input side of the power conversion device 1. When the magnitude of the DC link voltage is smaller than the withstand voltage of each capacitor, the power conversion device 1 for the low DC voltage mode in which the first capacitor bank 12 and the second capacitor bank 13 are connected in parallel is manufactured. When the magnitude of the DC link voltage is larger than the withstand voltage of each capacitor, the power conversion device 1 for the high DC voltage mode in which the first capacitor bank 12 and the second capacitor bank 13 are connected in series is manufactured. By selectively switching the electrical connection relationships of the first terminal portion 14, the second terminal portions 15 and 15', the third terminal portions 16 and 16', and the fourth terminal portion 17, the power conversion device 1 for the low DC voltage mode and the power conversion device 1 for the high DC voltage mode can be manufactured respectively. Thus, common use of many components between the power conversion device 1 for the low DC voltage mode and the power conversion device 1 for the high DC voltage mode can be achieved, and the manufacturing cost and manufacturing time of the power conversion device 1 can be reduced.

[0051] The first terminal portion 14 is electrically connected to the positive electrode of the first capacitor bank 12. In addition, the first terminal portion 14 is electrically connected to the positive DC terminal 41 for connecting the DC side of the power conversion device 1 to an external device (such as a rectifier). As described above, since the positive electrode of the first capacitor bank 12 is electrically connected to the positive electrode on the DC input side of the inverter unit 11, the positive DC terminal 41, the first terminal portion 14, and the positive electrode on the DC input side of the inverter unit 11 are at the same potential.

[0052] The second terminal portions 15 and 15' are electrically connected to the negative electrode of the first capacitor bank 12. In addition, since the second terminal portion 15 and the second terminal portion 15' are at the same potential, the second terminal portion 15' can be omitted and only the second terminal portion 15 can be provided.

[0053] The third terminal portions 16 and 16' are electrically connected to the positive electrode of the second capacitor bank 13. In addition, since the third terminal portion 16 and the third terminal portion 16' are at the same potential, the third terminal portion 16' can be omitted and only the third terminal portion 16 can be provided.

[0054] The fourth terminal portion 17 is electrically connected to the negative electrode of the second capacitor bank 13. In addition, the fourth terminal portion 17 is electrically connected to the negative DC terminal 42 for connecting the DC side of the power conversion device 1 to an external device (such as a rectifier). As described above, since the negative electrode of the second capacitor bank 13 is electrically connected to the negative electrode on the DC input side of the inverter unit 11, the negative DC terminal 42, the fourth terminal portion 17, and the negative electrode on the DC input side of the inverter unit 11 are at the same potential.

[0055] Figure 2A It is a cross-sectional view showing the 1st to 4th terminal portions formed by pads in through-holes. Figure 2B It is a front view showing the 1st to 4th terminal portions formed by pads in through-holes. As Figure 2A and Figure 2B shown, the 1st terminal portion 14, the 2nd terminal portions 15, 15', the 3rd terminal portions 16, 16', and the 4th terminal portion 17 are respectively provided as, for example, pads 51 in through-holes. The pad 51 is a conductor pattern for physically mounting components and making electrical connections. The shape of the hole of the pad 51 does not particularly limit this embodiment, and it may be Figure 2A and Figure 2B the round holes shown, or it may be an oblong hole, or it may be a square hole. The 1st terminal portion 14, the 2nd terminal portions 15, 15', the 3rd terminal portions 16, 16', and the 4th terminal portion 17 formed by the pads 51 are provided on an insulating substrate 50 that is a printed board or a mold board.

[0056] In the 1st embodiment, as Figure 1A shown, the distance between the 1st terminal portion 14 and the 3rd terminal portion 16 provided on the insulating substrate 50 is the same as the distance between the 2nd terminal portion 15 and the 4th terminal portion 17. These two distances do not have to be strictly the same, as long as they are approximately the same to the extent that the 1st electric conductor 21 and the 2nd electric conductor 22, which will be described later and are formed to be of the same length, can be electrically connected between the 1st terminal portion 14 and the 3rd terminal portion 16 and between the 2nd terminal portion 15 and the 4th terminal portion 17, respectively. In addition, in the 1st embodiment, the distances between the respective terminals of the 1st terminal portion 14, the 2nd terminal portions 15 and 15', the 3rd terminal portions 16 and 16', and the 4th terminal portion 17, other than between the 1st terminal portion 14 and the 3rd terminal portion 16 and between the 2nd terminal portion 15 and the 4th terminal portion 17 listed here, can be set arbitrarily.

[0057] In the insulating substrate 50, the 1st terminal portion 14 and the 3rd terminal portion 16 can be electrically connected by the 1st electric conductor 21, and the 2nd terminal portion 15 and the 4th terminal portion 17 can be electrically connected by the 2nd electric conductor 22. In addition, in the insulating substrate 50, the 2nd terminal portion 15' and the 3rd terminal portion 16' can be electrically connected by the 3rd electric conductor 23. Furthermore, in the case where the 2nd terminal portion 15' and the 3rd terminal portion 16' are omitted, the 2nd terminal portion 15 and the 3rd terminal portion 16 can be electrically connected by the 3rd electric conductor 23.

[0058] The first conductor 21, the second conductor 22, and the third conductor 23 are switching components for selectively switching the connection relationships of the first capacitor bank 12 and the second capacitor bank 13 within the power conversion device 1. As the first conductor 21, the second conductor 22, and the third conductor 23, there are, for example, bus bars, conductive cables, or conductive members with an insulating film covering the outer peripheral surface, etc. Bus bars and conductive cables are conductors for conducting large-capacity currents and are manufactured by sheet metal processing of metals such as copper, brass, or aluminum. Regarding the conductive member with an insulating film, similarly, its conductive member part is a conductor for conducting large-capacity currents and is manufactured by sheet metal processing of metals such as copper, brass, or aluminum. In particular, when the first conductor 21, the second conductor 22, and the third conductor 23 are respectively constituted by conductive members with an insulating film, for the connection parts of the conductive members with an insulating film to the respective terminal parts, the insulating film is peeled off and the conductive member is exposed to the outside. The conductive cable and the conductive member with an insulating film can have high rigidity or can also have flexibility. In the following embodiments, as an example, the case where the first conductor 21, the second conductor 22, and the third conductor 23 are respectively constituted by bus bars will be described.

[0059] In the first embodiment, since the distance between the first terminal part 14 and the third terminal part 16 is substantially the same as the distance between the second terminal part 15 and the fourth terminal part 17, the first conductor 21 and the second conductor 22 are manufactured by sheet metal processing using the same metal mold so that they have the same length. Therefore, according to the first embodiment, it is only necessary to manufacture two types of switching components, namely, the switching components serving as the first conductor 21 and the second conductor 22 and the switching component serving as the third conductor 23, by sheet metal processing. Thus, since the first conductor 21 and the second conductor 22 can be manufactured as common switching components, the types of switching components can be reduced.

[0060] By using the first conductor 21, the second conductor 22, and the third conductor 23 to switch the electrical connection relationships between the first terminal portion 14 and the third terminal portion 16, between the second terminal portion 15 and the fourth terminal portion 17, and between the second terminal portion 15' and the third terminal portion 16', the connection relationships of the first capacitor bank 12 and the second capacitor bank 13 in the power conversion device 1 can be selectively switched. In addition, when the second terminal portion 15' and the third terminal portion 16' are omitted, by using the first conductor 21, the second conductor 22, and the third conductor 23 to switch the electrical connection relationships between the first terminal portion 14 and the third terminal portion 16, between the second terminal portion 15 and the fourth terminal portion 17, and between the second terminal portion 15 and the third terminal portion 16, the connection relationships of the first capacitor bank 12 and the second capacitor bank 13 in the power conversion device 1 can be selectively switched.

[0061] Figure 3A FIG. is a diagram showing a power conversion device in a low DC voltage mode according to a first embodiment of the present invention, and is a front view showing an arrangement example of the first conductor and the second conductor. Figure 3B FIG. is a circuit diagram of a power conversion device in a low DC voltage mode according to a first embodiment of the present invention.

[0062] In the power conversion device 1 to which a low-voltage AC power supply is connected to a rectifier (not shown) connected to the DC side, the DC voltage of the input inverter section 11, that is, the DC link voltage, also becomes a low voltage (for example, 200 [V]). Assuming that the power conversion device 1 is used in an environment where the magnitude of the DC link voltage is greater than the withstand voltage of each capacitor, when manufacturing the power conversion device 1, the electrical connection for the low DC voltage mode is performed as Figure 3A and Figure 3B shown. That is, in the low DC voltage mode, the first terminal portion 14 and the third terminal portion 16 are electrically connected by the first conductor 21, and the second terminal portion 15 and the fourth terminal portion 17 are electrically connected by the second conductor 22. For convenience, the conductors connecting the first terminal portion 14 and the third terminal portion 16 and the second terminal portion 15 and the fourth terminal portion 17 are respectively referred to as "first" and "second". However, as described above, the distances between the first terminal portion 14 and the third terminal portion 16 and between the second terminal portion 15 and the fourth terminal portion 17 are substantially the same, so the first conductor 21 and the second conductor 22 are conductors having the same shape.

[0063] As Figure 3BAs shown, in the low DC voltage mode, the first terminal portion 14 and the third terminal portion 16 are electrically connected, and the second terminal portion 15 and the fourth terminal portion 17 are electrically connected. Thus, the first capacitor bank 12 and the second capacitor bank 13 are in a state of being electrically connected in parallel. That is, in the power conversion device 1 in the low DC voltage mode, eight capacitors connected in parallel function as smoothing capacitors (DC link capacitors). In addition, since the DC voltage appearing between the positive DC terminal 41 and the negative DC terminal 42 is applied to these eight capacitors connected in parallel, the first resistor 18 and the second resistor 19 do not function as voltage dividing resistors. When the DC voltage appearing between the positive DC terminal 41 and the negative DC terminal 42 is, for example, 200 [V], each capacitor in the first capacitor bank 12 and the second capacitor bank 13 is applied with 200 [V].

[0064] Figure 4A FIG. is a diagram showing a power conversion device in a high DC voltage mode according to the first embodiment of the present invention, and is a front view showing an example of the arrangement of a third conductor. Figure 4B FIG. is a diagram showing a power conversion device in a high DC voltage mode according to the first embodiment of the present invention, and is a circuit diagram of the power conversion device.

[0065] In a power conversion device 1 to which a high-voltage AC power supply is connected to a rectifier (not shown) connected to the DC side, the DC voltage input to the inverter section 11, that is, the DC link voltage, also becomes high voltage (for example, 400 [V]). Assuming that the power conversion device 1 is used in an environment where the magnitude of the DC link voltage is smaller than the withstand voltage of each capacitor, when manufacturing the power conversion device 1, the electrical connection for the high DC voltage mode is performed as Figure 4A and Figure 4B shown. That is, in the high DC voltage mode, the second terminal portion 15' and the third terminal portion 16' are electrically connected by the third conductor 23. In addition, when the second terminal portion 15' and the third terminal portion 16' are omitted and only the second terminal portion 15 and the third terminal portion 16 are provided, in the high DC voltage mode, the second terminal portion 15 and the third terminal portion 16 are electrically connected by the third conductor 23.

[0066] As Figure 4BAs shown, in the high DC voltage mode, the second terminal portion 15' and the third terminal portion 16' are electrically connected through the third electrical conductor 23. Thus, the first capacitor bank 12 and the second capacitor bank 13 are in a series-connected state. That is, in the power conversion device 1 in the high DC voltage mode, the first capacitor bank 12 and the second capacitor bank 13 connected in series with each other function as smoothing capacitors (DC link capacitors). As described above, the first resistor 18 and the second resistor 19 having the same resistance value are respectively connected in parallel with the first capacitor bank 12 and the second capacitor bank 13. Therefore, the voltage applied between the positive DC terminal 41 and the negative DC terminal 42 is divided by the first resistor 18 and the second resistor 19, so that the same magnitude of voltage is applied to the first capacitor bank 12 and the second capacitor bank 13 respectively. When the DC voltage appearing between the positive DC terminal 41 and the negative DC terminal 42 is, for example, 400 [V], each capacitor in the first capacitor bank 12 is applied with 200 [V], and each capacitor in the second capacitor bank 13 is applied with 200 [V]. Thus, according to Figure 4A and Figure 4B shown in the high DC voltage mode, the second terminal portion 15' (or 15) and the third terminal portion 16' (or 16) are electrically connected through the third electrical conductor 23. Thus, the first capacitor bank 12 and the second capacitor bank 13 are connected in series, so compared with Figure 3A and Figure 3B the low DC voltage mode shown, it can cope with the input of a higher DC voltage.

[0067] Figure 5 FIG. is an external view of the power conversion device according to the first embodiment of the present invention.

[0068] As Figure 5 illustrated, on one side surface of the housing of the power conversion device 1, that is, on the insulating substrate 50, the first terminal portion 14, the second terminal portions 15, 15', the third terminal portions 16, 16', the fourth terminal portion 17, the first resistor 18, and the second resistor 19 are provided, and the positive DC terminal 41 and the negative DC terminal 42 are provided on the DC input side. In addition, in Figure 5 , for the sake of simplicity of explanation, both the low DC voltage mode realized by connecting the first electrical conductor 21 and the second electrical conductor 22 and the high DC voltage mode realized by connecting the third electrical conductor 23 are shown, but actually either one of these DC voltage modes is selected.

[0069] As described above, according to the first embodiment, when manufacturing the power conversion device 1 for the low DC voltage mode, the first terminal portion 14 and the third terminal portion 16 are electrically connected through the first electrical conductor 21, and the second terminal portion 15 and the fourth terminal portion 17 are electrically connected through the second electrical conductor 22. As described above, the first electrical conductor 21 and the second electrical conductor 22 are switching members having the same shape. In addition, when manufacturing the power conversion device 1 for the high DC voltage mode, the second terminal portion 15' and the third terminal portion 16' are electrically connected through the third electrical conductor 23. In this way, by using the first electrical conductor 21, the second electrical conductor 22, and the third electrical conductor 23, the electrical connection relationships between the first terminal portion 14 and the third terminal portion 16, between the second terminal portion 15 and the fourth terminal portion 17, and between the second terminal portion 15' and the third terminal portion 16' are switched, and the connection relationship between the first capacitor bank 12 and the second capacitor bank 13 in the power conversion device 1 can be selectively switched.

[0070] Figure 6 FIG. is a diagram of a motor drive device including the power conversion device according to the first to fourth embodiments of the present invention. In addition, in Figure 6 In order to simplify the drawings, by convention, a combination of one wire "-" and three slashes " / / / " is used to label the three-phase wiring related to the AC power supply 3 and the motor 4.

[0071] By providing the power conversion device 1 of the above-described first embodiment or the second or third embodiment described later on the motor drive device 100, it is possible to easily and inexpensively manufacture a motor drive device 100 that can respectively cope with low AC power supply voltages and high AC power supply voltages. Here, the case where the power conversion device 1 of the above-described first embodiment is provided on the motor drive device 100 has been described, but the same description also holds for the case where the power conversion device of the second or third embodiment described later is provided on the motor drive device 100.

[0072] The motor drive device 100 includes a rectifier 2 and a power conversion device 1 having an inverter section 11.

[0073] An AC power supply 3 is connected to the AC side of the rectifier 2. The number of phases of the AC power supply 3 does not particularly limit this embodiment. For example, it can be three-phase or single-phase. In the illustrated example, the AC power supply 3 is set to three-phase. If an example of the AC power supply 3 is given, there are a three-phase AC 400V power supply, a three-phase AC 200V power supply, a three-phase AC 600V power supply, a single-phase AC 100V power supply, and the like.

[0074] The DC side of the rectifier 2 is connected to the positive DC terminal 41 and the negative DC terminal 42 of the power conversion device 1. In the power conversion device 1 having the positive DC terminal 41 and the negative DC terminal 42 as DC input terminals, the connection relationship of the first capacitor bank 12 and the second capacitor bank 13 can be selectively switched. These first capacitor bank 12 and second capacitor bank 13 function as so-called DC link capacitors that suppress the pulsating components of the DC voltage output by the rectifier 2 and store the DC power used for the inverter section 11 to output an AC voltage.

[0075] The rectifier 2 converts the AC voltage input from the AC power supply 3 into a DC voltage and then outputs it. As an example of the rectifier 2, there are a diode rectifier circuit, a 120-degree conduction rectifier circuit, or a PWM converter having a switching element inside, etc. In Figure 6 In the illustrated example, since the AC power supply 3 is three-phase, the rectifier 2 is configured as a three-phase bridge circuit. When the AC power supply 3 is single-phase, the rectifier 2 is composed of a single-phase bridge circuit. When the rectifier 2 is a 120-degree conduction rectifier circuit or a PWM converter, the rectifier 2 not only converts the AC voltage input from the AC power supply 3 into DC power and outputs it, but also converts the DC voltage input from the DC side into an AC voltage and outputs it to the AC power supply 3 side during power regeneration. When the rectifier 2 is a PWM converter, it is composed of a bridge circuit of a switching element and a diode connected in anti-parallel with the switching element. In this case, as an example of the switching element, there are FET, IGBT, thyristor, GTO, SiC, transistor, etc., but the type of the switching element itself does not limit this embodiment, and other switching elements may also be used. In addition, an AC reactor, an AC line filter, etc. are provided on the AC input side of the rectifier 2, but the illustration is omitted here.

[0076] The AC side of the power conversion device 1 having the inverter section 11 is connected to the motor 4. In this embodiment, the type of the motor 4 is not particularly limited. For example, it can be an induction motor or a synchronous motor. The number of phases of the motor 4 does not particularly limit this embodiment. For example, it can be three-phase or single-phase. In the illustrated example, the motor 4 is set to be three-phase. The machines provided with the motor 4 include, for example, machine tools, robots, forging machines, injection molding machines, industrial machines, various electrical appliances, electric trains, automobiles, airplanes, etc.

[0077] The power conversion device 1 converts the DC voltage input from the rectifier 2 into an AC voltage for driving the motor 4 via the positive DC terminal 41 and the negative DC terminal 42 and outputs it between the terminals on the AC side. The process of converting the DC voltage into an AC voltage is performed by the inverter section 11 within the power conversion device 1. Similar to a general motor drive device, the inverter section 11 is controlled by the above-described inverter control section (not shown). That is, the inverter control section is based on the actual speed of the motor 4 (speed feedback) detected by the speed sensor, the current flowing through the windings of the motor 4 (current feedback), a predetermined torque command, and the operation program of the motor 4, etc., and generates a voltage command for controlling the speed, torque, or rotor position of the motor 4 according to, for example, the PWM control method. Based on the voltage command generated by the inverter control section, the voltage conversion operation performed by the inverter section 11 is controlled, and as a result, the drive of the motor 4 is controlled. The inverter control section can achieve the above functions by causing an arithmetic processing device such as a DSP or FPGA located within the motor drive device 100 to operate according to this software program.

[0078] In the power conversion device 1, a low DC voltage mode is achieved by using the first conductor 21 and the second conductor 22 to connect the first capacitor bank 12 and the second capacitor bank 13 in parallel, and a high DC voltage mode is achieved by using the third conductor 23 to connect the first capacitor bank 12 and the second capacitor bank 13 in series. Therefore, by providing the power conversion device 1 on the motor drive device 100, it is possible to easily and inexpensively manufacture a motor drive device 100 that can respectively cope with low AC power supply voltages and high AC power supply voltages.

[0079] Next, a second embodiment of the present invention will be described. Figure 7A It is a diagram showing the power conversion device of the second embodiment of the present invention and is a front view illustrating the arrangement of the first to fourth terminal portions within the power conversion device. Figure 7B It is a circuit diagram of the power conversion device of the second embodiment of the present invention.

[0080] In the second embodiment, further regarding the distance between the second terminal portion 15 and the third terminal portion 16 in the first embodiment, it is also substantially the same as the distance between the first terminal portion 14 and the third terminal portion 16 and the distance between the second terminal portion 15 and the fourth terminal portion 17.

[0081] That is, in the power conversion device 1 according to the second embodiment of the present invention, the distance between the first terminal portion 14 and the third terminal portion 16, the distance between the second terminal portion 15 and the fourth terminal portion 17, and the distance between the second terminal portion 15 and the third terminal portion 16 are the same. These three distances do not have to be exactly the same, as long as they are approximately the same to the extent that the first electric conductor 21, the second electric conductor 22, and the third electric conductor 23 formed to the same length can be electrically connected between the first terminal portion 14 and the third terminal portion 16, between the second terminal portion 15 and the fourth terminal portion 17, and between the second terminal portion 15 and the third terminal portion 16, respectively. In addition, the distances between the respective terminals of the first terminal portion 14, the second terminal portion 15, 15', the third terminal portion 16, 16', and the fourth terminal portion 17, other than those listed here as "between the first terminal portion 14 and the third terminal portion 16, between the second terminal portion 15 and the fourth terminal portion 17, and between the second terminal portion 15 and the fourth terminal portion 17", can be arbitrarily set.

[0082] In the second embodiment, since the distance between the first terminal portion 14 and the third terminal portion 16, the distance between the second terminal portion 15 and the fourth terminal portion 17, and the distance between the second terminal portion 15 and the third terminal portion 16 are approximately the same, the first electric conductor 21, the second electric conductor 22, and the third electric conductor 23 are manufactured by sheet metal processing using the same mold so that they have the same length. Thus, according to the second embodiment, the first electric conductor 21, the second electric conductor 22, and the third electric conductor 23 can be manufactured as common switching components, and therefore, compared with the first embodiment, the types of switching components can be further reduced.

[0083] As described above, according to the second embodiment, by using the first electric conductor 21, the second electric conductor 22, and the third electric conductor 23 manufactured by the same sheet metal processing to switch the electrical connection relationship between the first terminal portion 14 and the third terminal portion 16, between the second terminal portion 15 and the fourth terminal portion 17, and between the second terminal portion 15 and the third terminal portion 16, the connection relationship between the first capacitor bank 12 and the second capacitor bank 13 in the power conversion device 1 can be selectively switched.

[0084] Except for the matters related to the distances between the respective terminals described above, the configurations of the inverter unit 11, the first capacitor bank 12, the second capacitor bank 13, the first electric conductor 21, the second electric conductor 22, and the third electric conductor 23, and the connection relationships of the respective parts are the same as those in the first embodiment.

[0085] Figure 8A It is a front view showing an arrangement example of the first to third electric conductors in the power conversion device according to the second embodiment of the present invention, and shows an arrangement example of the first to third electric conductors in the low DC voltage mode.Figure 8B This is a front view showing an arrangement example of the first to third electrical conductors in the power conversion device according to the second embodiment of the present invention, and shows an arrangement example of the first to third electrical conductors in the high DC voltage mode.

[0086] When manufacturing the power conversion device 1 for the low DC voltage mode, as Figure 8A shown, the first terminal portion 14 and the third terminal portion 16 are electrically connected by the first electrical conductor 21, and the second terminal portion 15 and the fourth terminal portion 17 are electrically connected by the second electrical conductor 22. Thereby, Figure 7B the first capacitor bank 12 and the second capacitor bank 13 shown are connected in parallel.

[0087] In addition, when manufacturing the power conversion device 1 for the high DC voltage mode, as Figure 8B shown, the second terminal portion 15 and the third terminal portion 16 are electrically connected by the third electrical conductor 23. Thereby, Figure 7B the first capacitor bank 12 and the second capacitor bank 13 shown are connected in series.

[0088] Thus, in the second embodiment, since the distance between the first terminal portion 14 and the third terminal portion 16, the distance between the second terminal portion 15 and the fourth terminal portion 17, and the distance between the second terminal portion 15 and the third terminal portion 16 are substantially the same, a switching member (i.e., the first electrical conductor 21, the second electrical conductor 22, and the third electrical conductor 23) composed of electrical conductors of the same shape can be used for the connection between these terminals.

[0089] Next, a description will be given of the third embodiment of the present invention. Figure 9A This is a circuit diagram showing the power conversion device according to the third embodiment of the present invention, and shows the power conversion device when no electrical conductor is connected. Figure 9B This is a circuit diagram showing the power conversion device according to the third embodiment of the present invention, and shows the power conversion device in the low DC voltage mode. Figure 9C This is a circuit diagram showing the power conversion device according to the third embodiment of the present invention, and shows the power conversion device in the high DC voltage mode.

[0090] In the third embodiment, regarding the first resistor 18 and the second resistor 19 in the first embodiment or the second embodiment, they are not installed in the power conversion device 1 for the low DC voltage mode, but are installed in the power conversion device 1 for the high DC voltage mode.

[0091] As described above, the first resistor 18 and the second resistor 19 function as voltage dividing resistors for preventing voltage imbalance between the first capacitor bank 12 and the second capacitor bank 13 connected in series in the high DC voltage mode. On the other hand, in the low DC voltage mode, since the first capacitor bank 12 and the second capacitor bank 13 are connected in parallel and the voltages applied to the first capacitor bank 12 and the second capacitor bank 13 are of the same magnitude, the first resistor 18 and the second resistor 19 do not function as voltage dividing resistors. Therefore, in the third embodiment, when manufacturing the power conversion device 1 for the low DC voltage mode, the installation of the first resistor 18 and the second resistor 19 is omitted, and when manufacturing the power conversion device 1 for the high DC voltage mode, the first resistor 18 and the second resistor 19 are installed. Generally, pads for connecting the first resistor 18 and the second resistor 19 are provided on the insulating substrate, but in the third embodiment, the pads left vacant due to the non-installation of the first resistor 18 and the second resistor 19 in the low DC voltage mode are effectively utilized as the first terminal portion 14 and the fourth terminal portion 17.

[0092] As Figure 9A shown, one end of the first resistor 18 is connected to the first terminal portion 14 and is connected in parallel with the first capacitor bank 12. One end of the second resistor 19 is connected to the fourth terminal portion 17 and is connected in parallel with the second capacitor bank 13.

[0093] When manufacturing the power conversion device 1 for the low DC voltage mode, as Figure 9B shown, the first resistor 18 and the second resistor 19 are not installed. Moreover, the first terminal portion 14, which is the pad left vacant due to the non-installation, is electrically connected to the third terminal portion 16 through the first conductor 21. In addition, the second terminal portion 15 is electrically connected to the fourth terminal portion 17, which is the pad left vacant due to the non-installation, through the second conductor 22. Thus, Figure 9B the first capacitor bank 12 shown is connected in parallel with the second capacitor bank 13.

[0094] In addition, when manufacturing the power conversion device 1 for the high DC voltage mode, as Figure 9C shown, one end of the first resistor 18 is connected to the first terminal portion 14 and is installed in parallel with the first capacitor bank 12. In addition, one end of the second resistor 19 is connected to the fourth terminal portion 17 and is connected in parallel with the second capacitor bank 13. Moreover, the second terminal portion 15 is electrically connected to the third terminal portion 16 through the third conductor 23. Thus, Figure 9C the first capacitor bank 12 shown is connected in series with the second capacitor bank 13.

[0095] In the first and second embodiments, it is necessary to provide pads on the insulating substrate for the two connection portions for the first resistor 18, the two connection portions for the second resistor 19, the first terminal portion 14, the second terminal portion 15 (and 15'), the third terminal portion 16 (and 16'), and the fourth terminal portion 17, respectively. In contrast, in the third embodiment, since one of the two connection portions for the first resistor 18 is shared with the first terminal portion 14 and one of the two connection portions for the second resistor 19 is shared with the fourth terminal portion 17, the occupied area of the components mounted on the insulating substrate can be reduced. Further, as described in connection with the first embodiment, the distance between the first terminal portion 14 and the third terminal portion 16 and the distance between the second terminal portion 15 and the fourth terminal portion 17 may be substantially the same, or as described in connection with the second embodiment, the distance between the first terminal portion 14 and the third terminal portion 16, the distance between the second terminal portion 15 and the fourth terminal portion 17, and the distance between the second terminal portion 15 and the third terminal portion 16 may be substantially the same.

[0096] Regarding the setting of the connection relationship of the first capacitor bank 12 and the second capacitor bank 13 using the first conductor 21, the second conductor 22, and the third conductor 23 in the power conversion device 1 of the first to third embodiments described above, it is performed when manufacturing the power conversion device 1 (or when manufacturing the motor drive device 100 having the power conversion device 1). That is, in the process of manufacturing the power conversion device 1 connected to the low-voltage AC power supply, the operator electrically connects between the first terminal portion 14 and the third terminal portion 16 through the first conductor 21, and electrically connects between the second terminal portion 15 and the fourth terminal portion 17 through the second conductor 22 to manufacture the power conversion device 1 for the low DC voltage mode. Further, in the process of manufacturing the power conversion device 1 connected to the high-voltage AC power supply, the operator electrically connects between the second terminal portion 15 (or 15') and the third terminal portion 16 (or 16') through the third conductor 23 to manufacture the power conversion device 1 for the high DC voltage mode. Alternatively, when the operator repairs the manufactured power conversion device 1, the first conductor 21, the second conductor 22, and the third conductor 23 can be used to switch the setting of the connection relationship of the first capacitor bank 12 and the second capacitor bank 13 from the low DC voltage mode to the high DC voltage mode or from the high DC voltage mode to the low DC voltage mode. Further, in the first to third embodiments described above, it is assumed that the operator manufactures the power conversion device 1, but alternatively, the power conversion device 1 may be manufactured jointly by the operator and the machine tool, or the power conversion device 1 may be manufactured by the machine tool alone.

[0097] Next, a fourth embodiment of the present invention will be described. Figure 10This is a circuit diagram of the power conversion device according to the fourth embodiment of the present invention.

[0098] In the fourth embodiment, when manufacturing the power conversion device 1 of the first to third embodiments, it is possible to check whether the power conversion device 1 has an abnormality. As an example of the abnormality of the power conversion device 1 that can be detected by the inspection of the fourth embodiment, there are short circuits, burnouts of capacitors in the first capacitor bank 12 and the second capacitor bank 13, failures of semiconductor switching elements in the power conversion device 1, short circuits of various wirings in the power conversion device 1, and the like. In addition, it can also be determined by the inspection in the fourth embodiment whether the power conversion device 1 can be manufactured in the DC power mode desired by the operator.

[0099] According to the fourth embodiment, the power conversion device 1 further includes: a first voltage detection unit 31, a second voltage detection unit 32, and an alarm output unit 33.

[0100] The first voltage detection unit 31 detects the voltage V 41 occurring between the fourth terminal portion 17 and the first terminal portion 14. As described above, since the positive DC terminal 41 and the first terminal portion 14 have the same potential, and the negative DC terminal 42 and the fourth terminal portion 17 have the same potential, the voltage occurring between the fourth terminal portion 17 and the first terminal portion 14 and the voltage occurring between the positive DC terminal 41 and the negative DC terminal 42 are of the same magnitude V 41 . Therefore, as Figure 10 shown, in order to detect the voltage occurring between the fourth terminal portion 17 and the first terminal portion 14, the first voltage detection unit 31 detects the voltage V 41 occurring between the positive DC terminal 41 and the negative DC terminal 42. The voltage V 41 occurring between the positive DC terminal 41 and the negative DC terminal 42 is so-called "DC link voltage", which is used to control the inverter unit 11 in the power conversion device 1 and control the motor drive device 100 having the power conversion device 1. Therefore, since the power conversion device 1 and the motor drive device 100 generally have a voltage detector for detecting the DC link voltage, this voltage detector can be used as the first voltage detection unit 31.

[0101] The second voltage detection unit 32 detects the voltage V 43 occurring between the fourth terminal portion 17 and the third terminal portion 16 (or 16'). Similar to the first voltage detection unit 31 described above, when the power conversion device 1 and the motor drive device 100 have a voltage detector for detecting the DC link voltage, this voltage detector can be used as the second voltage detection unit 32.

[0102] The first voltage detection unit 31 and the second voltage detection unit 32 are constituted by, for example, a combination of an operational amplifier, a logic IC, and an insulating element, an insulated AD converter, or the like.

[0103] When the first capacitor bank 12 and the second capacitor bank 13 are charged, the alarm output unit 33 outputs an alarm based on the voltage V between the fourth terminal portion 17 and the first terminal portion 14 detected by the first voltage detection unit 31 41 and the voltage V between the fourth terminal portion 17 and the third terminal portion 16 detected by the second voltage detection unit 32. 43 to output an alarm.

[0104] The alarm output unit 33 can be constructed in the form of, for example, a software program, or can also be constructed by a combination of various electronic circuits and a software program. For example, when the alarm output unit 33 is constructed in the form of a software program, by causing the arithmetic processing device to operate according to the software program, the functions of the above-described alarm output unit 33 can be realized. Alternatively, it can also be realized as a semiconductor integrated circuit in which a software program for realizing the functions of the alarm output unit 33 is written.

[0105] The inspection of the power conversion device 1 is performed by monitoring the voltage V between the fourth terminal portion 17 and the first terminal portion 14 41 and the voltage V between the fourth terminal portion 17 and the third terminal portion 16. 43 In addition, in the power conversion device 1 manufactured for the low DC voltage mode and the power conversion device 1 manufactured for the high DC voltage mode, the conditions for the alarm output unit 33 to output an alarm are different. Therefore, as a previous stage of inspecting the power conversion device 1, the first capacitor bank 12 and the second capacitor bank 13 are charged in advance. In addition, information indicating whether it is the low DC voltage mode or the high DC voltage mode is input into the alarm output unit 33 in advance via an input device (not shown) such as a keyboard, a mouse, or a touch panel. The following inspections are performed on the power conversion device 1 manufactured for the low DC voltage mode and the power conversion device 1 manufactured for the high DC voltage mode, respectively, on the basis of these two preparations.

[0106] In the case of the power conversion device 1 manufactured for the low DC voltage mode, since the first capacitor bank 12 and the second capacitor bank 13 are connected in parallel via the first conductor 21 and the second conductor 22, if there is no abnormality, the voltage V between the fourth terminal portion 17 and the first terminal portion 14 41 and the voltage V between the fourth terminal portion 17 and the third terminal portion 16 43 should be the same. Conversely, when the voltage V between the fourth terminal portion 17 and the first terminal portion 14 41 and the voltage V between the fourth terminal portion 17 and the third terminal portion 1643 When they are inconsistent, there are some abnormalities in the power conversion device 1. Therefore, in the power conversion device 1 manufactured for the low DC voltage mode, when the voltage V between the fourth terminal portion 17 and the first terminal portion 14 detected by the first voltage detection unit 31 41 and the voltage V between the fourth terminal portion 17 and the third terminal portion 16 detected by the second voltage detection unit 32 43 are inconsistent, the alarm output unit 33 outputs an alarm. In addition, there is a possibility that slight voltage fluctuations occur in the voltages of the first capacitor bank 12 and the second capacitor bank 13. Therefore, in the state where the first capacitor bank 12 and the second capacitor bank 13 of the power conversion device 1 manufactured for the low DC voltage mode are charged, when the voltage V between the fourth terminal portion 17 and the first terminal portion 14 detected by the first voltage detection unit 31 41 and the voltage V between the fourth terminal portion 17 and the third terminal portion 16 detected by the second voltage detection unit 32 43 differ by more than a preset first voltage range, the alarm output unit 33 outputs an alarm. Here, the above-mentioned first voltage range used for the determination process of the alarm output unit 33 is set to, for example, about ± several % of the voltage V 41 (DC link voltage) between the fourth terminal portion 17 and the first terminal portion 14.

[0107] In the case of the power conversion device 1 manufactured for the high DC voltage mode, since the first capacitor bank 12 and the second capacitor bank 13 are connected in series via the third conductor 23, if there is no abnormality, the voltage V between the fourth terminal portion 17 and the first terminal portion 14 41 should be twice the voltage V between the fourth terminal portion 17 and the third terminal portion 16 43 . Conversely, when the voltage V between the fourth terminal portion 17 and the first terminal portion 14 41 is not twice the voltage V between the fourth terminal portion 17 and the third terminal portion 16 43 , there are some abnormalities in the power conversion device 1. Therefore, in the power conversion device 1 manufactured for the high DC voltage mode, when the voltage V between the fourth terminal portion 17 and the first terminal portion 14 detected by the first voltage detection unit 31 41 is not the voltage V between the fourth terminal portion 17 and the third terminal portion 16 detected by the second voltage detection unit 32 43When it is approximately twice that value, the alarm output unit 33 outputs an alarm. As described above, there is a possibility of slight voltage fluctuations in the voltages of the first capacitor bank 12 and the second capacitor bank 13. Therefore, in a state where the first capacitor bank 12 and the second capacitor bank 13 of the power conversion device 1 manufactured for the high DC voltage mode are charged, when the voltage V between the fourth terminal portion 17 and the first terminal portion 14 detected by the first voltage detection unit 31 41 and the voltage V between the fourth terminal portion 17 and the third terminal portion 16 detected by the second voltage detection unit 32 43 The difference from twice the value is outside the preset second voltage range, the alarm output unit 33 outputs an alarm. Here, the above-mentioned second voltage range used for the determination process of the alarm output unit 33 is set to the voltage V between the fourth terminal portion 17 and the first terminal portion 14 41 (DC link voltage) is, for example, about ± several %.

[0108] In addition, a reporting unit (not shown) for reporting an abnormality to an operator using the alarm output from the alarm output unit 33 may be provided. As an example of the means of the reporting unit, there are the power conversion device 1, the motor drive device 100, or a display, a personal computer, a portable terminal, and a display such as a touch panel attached to the upper control device. For example, an indication such as "An abnormality has occurred" can be displayed on the display. Further, for example, the reporting unit can be implemented by a voice, a speaker, a buzzer, a sound device that emits a ringing sound, etc. Alternatively, a form of printing on paper or the like using a printer for display can also be adopted. Alternatively, these methods can be appropriately combined to implement.

[0109] Figure 11 is a flowchart showing an inspection process when manufacturing the power conversion device according to the fourth embodiment of the present invention.

[0110] When manufacturing the power conversion device 1, when the operator manufactures the power conversion device 1 for the low DC voltage mode, the first terminal portion 14 and the third terminal portion 16 (or 16') are electrically connected through the first electric conductor 21, and the second terminal portion 15 (or 15') and the fourth terminal portion 17 are electrically connected through the second electric conductor 22. In addition, when the operator manufactures the power conversion device 1 for the high DC voltage mode, the second terminal portion 15 (or 15') and the third terminal portion 16 (or 16') are electrically connected through the third electric conductor 23.

[0111] When the operator checks the manufactured power conversion device 1, the first capacitor bank 12 and the second capacitor bank 13 are pre-charged. In addition, information indicating whether the power conversion device 1 to be inspected is in the low DC voltage mode or the high DC voltage mode is pre-input into the alarm output unit 33 via an input device such as a keyboard, a mouse, or a touch panel.

[0112] Regarding the voltages of the charged first capacitor bank 12 and second capacitor bank 13, they are detected by the first voltage detection unit 31 and the second voltage detection unit 32. Specifically, the first voltage detection unit 31 detects the voltage V 41 generated between the fourth terminal portion 17 and the first terminal portion 14. The second voltage detection unit 32 detects the voltage V 43 generated between the fourth terminal portion 17 and the third terminal portion 16 (or 16’).

[0113] In step S101, the alarm output unit 33 determines whether the power conversion device 1 to be inspected is in the low DC voltage mode or the high DC voltage mode. The determination of the alarm output unit 33 is based on the information indicating whether it is in the low DC voltage mode or the high DC voltage mode that is pre-input into the alarm output unit 33. When it is determined to be in the low DC voltage mode in step S101, the process proceeds to step S102, and when it is determined to be in the high DC voltage mode in step S101, step S103 is performed.

[0114] In step S102, the alarm output unit 33 determines the voltage V 41 between the fourth terminal portion 17 and the first terminal portion 14 detected by the first voltage detection unit 31 and the voltage V 43 between the fourth terminal portion 17 and the third terminal portion 16 detected by the second voltage detection unit 32. The difference “V 41 -V 43 ” is determined whether it is outside a pre-specified first voltage range. Regarding the first voltage range, it is pre-set before the start of the inspection. For example, when the first threshold value V th1 is set as a positive value, the set first voltage range is defined as the range from -V th1 to V th1 . The alarm output unit 33 can determine the difference “V 41 -V 43 ” by determining whether the absolute value “|V 41 -V 43 |” exceeds the first threshold value V th1 , and can determine the voltage V 41 between the fourth terminal portion 17 and the first terminal portion 14 and the voltage V 43 between the fourth terminal portion 17 and the third terminal portion 16. The difference “V 41 -V 43”is outside the first voltage range. When it is determined in step S102 that the voltage V between the fourth terminal portion 17 and the first terminal portion 14 41 and the voltage V between the fourth terminal portion 17 and the third terminal portion 16 43 difference "V 41 -V 43 " is within the first voltage range, the power conversion device 1 manufactured for the low DC voltage mode is normal, and then the inspection process ends. When it is determined in step S102 that the voltage V between the fourth terminal portion 17 and the first terminal portion 14 41 and the voltage V between the fourth terminal portion 17 and the third terminal portion 16 43 difference "V 41 -V 43 " is outside the first voltage range, the process proceeds to step S103.

[0115] In step S104, the alarm output unit 33 determines the voltage V between the fourth terminal portion 17 and the first terminal portion 14 detected by the first voltage detection unit 31 41 and the voltage V between the fourth terminal portion 17 and the third terminal portion 16 detected by the second voltage detection unit 32 43 two - fold difference "V 41 -2V 43 " is outside a preset second voltage range. Regarding the second voltage range, it is preset before the start of the inspection. For example, when the second threshold V th2 is set as a positive value, the set second voltage range is delimited as the range from -V th2 to V th2 . The alarm output unit 33 can determine whether the two - fold difference "V 41 -2V 43 " is outside the second voltage range by determining whether the absolute value "|V 41 -2V 43 |" exceeds the second threshold V th2 . When it is determined in step S104 that the voltage V between the fourth terminal portion 17 and the first terminal portion 14 41 and the voltage V between the fourth terminal portion 17 and the third terminal portion 16 43 two - fold difference "V 41 -2V 43 " is outside the second voltage range. When it is determined in step S104 that the voltage V between the fourth terminal portion 17 and the first terminal portion 14 41 and the voltage V between the fourth terminal portion 17 and the third terminal portion 16 43 two - fold difference "V 41 -2V 43”When within the second voltage range, the power conversion device 1 manufactured for the high DC voltage mode is normal, and then the inspection process ends. When it is determined in step S104 that the voltage V between the fourth terminal portion 17 and the first terminal portion 14 41 and the voltage V between the fourth terminal portion 17 and the third terminal portion 16 43 the difference of twice “V 41 -2V 43 ” is outside the second voltage range, the process proceeds to step S103.

[0116] In step S103, the alarm output unit 33 outputs an alarm, and then the inspection process ends. As described above, a reporting unit (not shown) may be provided at the subsequent stage of the alarm output unit 33, and an abnormality occurrence may be reported to the operator based on the alarm output from the alarm output unit 33.

[0117] Figure 12 is a flowchart showing a modification example of the inspection process when manufacturing the power conversion device according to the fourth embodiment of the present invention. In this modification example, the determination condition in Figure 11 step S104 is changed.

[0118] The processes in steps S201 to S203 are the same as the processes in Figure 11 steps S101 to S103.

[0119] In step S204, the alarm output unit 33 determines whether the difference “V 41 half of the voltage between the fourth terminal portion 17 and the first terminal portion 14 detected by the first voltage detection unit 31 and the voltage V 43 between the fourth terminal portion 17 and the third terminal portion 16 detected by the second voltage detection unit 32 43 -V 41 ×1 / 2” is outside a preset second voltage range. The alarm output unit 33 can determine whether the difference “V 43 -V 41 ×1 / 2” is outside the second voltage range by determining whether the absolute value “|V 43 -V 41 ×1 / 2|” exceeds a second threshold value V th2 . When it is determined in step S204 that the difference “V 41 half of the voltage between the fourth terminal portion 17 and the first terminal portion 14 and the voltage V 43 between the fourth terminal portion 17 and the third terminal portion 16 43 -V 41 ×1 / 2” is outside the second voltage range. When it is determined in step S204 that the half voltage of the voltage V between the fourth terminal portion 17 and the first terminal portion 14 41 and the voltage V between the fourth terminal portion 17 and the third terminal portion 1643 The difference "V 43 - V 41 ×1 / 2" is within the second voltage range, the power conversion device 1 manufactured for the high DC voltage mode is normal, and then the inspection process ends. When it is determined in step S204 that the voltage V 41 between the fourth terminal portion 17 and the first terminal portion 14 and the voltage V 43 The difference "V 43 - V 41 ×1 / 2" is outside the second voltage range, step S203 is entered.

[0120] Regarding the above processes S101 to S104 and processes S201 to S204, it can be set to be automatically processed by an inspection device including the alarm output unit 33. For example, when the power conversion device 1 and the motor drive device 100 are equipped with a voltage detector for detecting the DC link voltage, this voltage detector can be used as the first voltage detection unit 31 and the second voltage detection unit 32. In this case, it can be set that when the inspection device including the alarm output unit 33 detects the connection with these first voltage detection unit 31 and second voltage detection unit 32, the above processes S101 to S104 or processes S201 to S204 are automatically executed. Alternatively, when the power conversion device 1 and the motor drive device 100 do not have a voltage detector for detecting the DC link voltage, it can be set that when the inspection device including the first voltage detection unit 31, the second voltage detection unit 32, and the alarm output unit 33 detects the connection with the power conversion device 1 to be inspected, the above processes S101 to S104 or processes S201 to S204 are automatically executed.

[0121] According to one aspect of the present invention, it is possible to realize a power conversion device and a motor drive device that are easy to manufacture and have low cost and can respectively cope with low AC power supply voltage and high AC power supply voltage.

Claims

1. A power conversion device, characterized in that, Comprising: An inverter section that converts an input DC voltage into an AC voltage and outputs it; A first capacitor bank composed of one or a plurality of capacitors connected in parallel with each other, and the positive electrode of the first capacitor bank is electrically connected to the positive electrode of the DC input side of the inverter section; A second capacitor bank composed of one or a plurality of capacitors connected in parallel with each other, and the negative electrode of the second capacitor bank is electrically connected to the negative electrode of the DC input side of the inverter section; A first terminal section that is electrically connected to the positive electrode of the first capacitor bank; A second terminal section that is electrically connected to the negative electrode of the first capacitor bank; A third terminal section that is electrically connected to the positive electrode of the second capacitor bank; and A fourth terminal section that is electrically connected to the negative electrode of the second capacitor bank, The distance between the first terminal section and the third terminal section and the distance between the second terminal section and the fourth terminal section are substantially the same, The distance between the first terminal section and the third terminal section, the distance between the second terminal section and the fourth terminal section, and the distance between the second terminal section and the third terminal section are substantially the same.

2. The power conversion device according to claim 1, wherein Comprising: A first electrical conductor for electrically connecting between the first terminal section and the third terminal section; A second electrical conductor for electrically connecting between the second terminal section and the fourth terminal section; and A third electrical conductor for electrically connecting between the second terminal section and the third terminal section.

3. The power conversion device according to claim 2, wherein As a mode of the DC voltage input to the inverter section, a low DC voltage mode and a high DC voltage mode are selectively switched. The low DC voltage mode is a mode in which the first terminal section and the third terminal section are electrically connected through the first electrical conductor and the second terminal section and the fourth terminal section are electrically connected through the second electrical conductor. The high DC voltage mode is a mode in which the second terminal section and the third terminal section are electrically connected through the third electrical conductor.

4. The power conversion device according to claim 3, wherein Comprising: A first resistor connected in parallel with the first capacitor bank. When connected in parallel, one end of the first resistor is connected to the first terminal section; and A second resistor connected in parallel with the second capacitor bank. When connected in parallel, one end of the second resistor is connected to the fourth terminal section, In the high DC voltage mode, the first resistor is connected in parallel with the first capacitor bank, and the second resistor is connected in parallel with the second capacitor bank, In the low DC voltage mode, the first resistor is removed from the first capacitor bank, and the second resistor is removed from the second capacitor bank.

5. The power conversion device according to claim 3 or 4, wherein The power conversion device further comprises: A first voltage detection section that detects the voltage generated between the fourth terminal section and the first terminal section; A second voltage detection section that detects the voltage generated between the fourth terminal section and the third terminal section; And An alarm output unit that, when the first capacitor bank and the second capacitor bank are charged, outputs an alarm based on the voltage between the fourth terminal portion and the first terminal portion detected by the first voltage detection unit and the voltage between the fourth terminal portion and the third terminal portion detected by the second voltage detection unit.

6. The power conversion device according to claim 5, wherein: In the low DC voltage mode, when the first capacitor bank and the second capacitor bank are charged, if the difference between the voltage between the fourth terminal portion and the first terminal portion detected by the first voltage detection unit and the voltage between the fourth terminal portion and the third terminal portion detected by the second voltage detection unit is outside a preset first voltage range, the alarm output unit outputs an alarm.

7. The power conversion device according to claim 5, wherein: In the high DC voltage mode, when the first capacitor bank and the second capacitor bank are charged, if the difference between twice the voltage between the fourth terminal portion and the first terminal portion detected by the first voltage detection unit and the voltage between the fourth terminal portion and the third terminal portion detected by the second voltage detection unit is outside a preset second voltage range, the alarm output unit outputs an alarm.

8. The power conversion device according to any one of claims 2 to 4, wherein: The first electrical conductor, the second electrical conductor, and the third electrical conductor are each constituted by a bus bar.

9. The power conversion device according to any one of claims 1 to 4, wherein: The first terminal portion, the second terminal portion, the third terminal portion, and the fourth terminal portion are each constituted by pads in vias.

10. A motor drive device, characterized in that, Comprising: A rectifier that converts an AC voltage input from an AC power source into a DC voltage and outputs it; and The power conversion device according to any one of claims 1 to 9, which is connected to the rectifier and converts the DC voltage input from the rectifier into an AC voltage for driving a motor and outputs it.

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