Inverter device

Abstract

To provide an inverter device that has an AC input terminal for a control power supply in addition to an AC input terminal for a main circuit, and can reduce the size of a configuration required for a noise filter function.SOLUTION: An inverter device of the embodiment includes: a first rectifier circuit that rectifies an AC voltage received from a power supply terminal for a main circuit and outputs it to a DC power supply line for the main circuit; a second rectifier circuit that rectifies an AC voltage received from a power supply terminal for control and outputs it to a DC power supply line for control; a diode that prevents reverse power flow from the DC power supply line for control to the DC power supply line side for the main circuit; a control power supply circuit that is connected to an inverter main circuit connected to the DC power supply line for the main circuit and to the DC power supply line for control, and that generates a control power supply voltage required for control of the inverter main circuit; and a filter circuit that is arranged in a power supply path common to both a power supply path from the first rectifier circuit to the control power supply circuit and a power supply path from the second rectifier circuit to the control power supply circuit.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] An embodiment of the present invention relates to an inverter device that includes an AC input terminal for a control power supply in addition to an AC input terminal for a main circuit. [Background technology]

[0002] Inverter devices output AC power at a desired frequency by switching on and off semiconductor elements that make up the inverter's main circuit, but this switching operation generates high-frequency noise that may affect external devices via the AC power line.To reduce the impact on external devices, inverter devices are available that have a built-in noise filter in the AC input section or that have an optional external noise filter connected.

[0003] Furthermore, inverter devices have a rectifier circuit that converts AC power supply voltage into DC voltage, which generates power supply harmonics as low-frequency noise. Countermeasures against these harmonics include placing an AC reactor on the power supply side of the rectifier circuit and placing a DC reactor in the DC section. In this application, filters for harmonics and filters for low-frequency noise are collectively referred to as noise filters.

[0004] Incidentally, some inverter devices are provided with a dedicated AC input terminal for generating a control power supply in addition to the AC input terminal, as disclosed in, for example, Patent Documents 1 and 2. Patent Documents 1 and 2 each propose a configuration in which a system in which a power supply separate from the AC input terminal for the main circuit is connected to the AC input terminal for the control power supply to supply power to the control power supply circuit, and a system in which power is also supplied to the control power supply circuit from a power supply connected to the AC input terminal for the main circuit, either of which can be used in common or can be selected by the user. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Publication No. 1-107665 [Patent Document 2] Patent No. 2550030 Summary of the Invention [Problem to be solved by the invention]

[0006] For example, as shown in Figure 1 of Patent Document 1, when a control power supply circuit performs switching operations using switching transistors, high-frequency noise is generated by the operations. Furthermore, when DC power is supplied to the control power supply circuit via a dedicated rectifier circuit, low-frequency noise is generated by the rectifier circuit. Therefore, when a power supply separate from the AC input terminal for the main circuit is connected to the AC input terminal for the control power supply to supply power to the control power supply circuit, a dedicated high-frequency noise filter for the control power supply and a noise filter for suppressing power supply harmonics are required, as shown in Figure 6.

[0007] 6, the noise filter placed at the AC input terminal for the inverter main circuit must deal with noise generated in the inverter main circuit, as well as noise generated by the control power supply circuit in case power is supplied to the control power supply circuit from the AC input terminal. In addition, since a noise filter for the control power supply is also placed, there is a problem that the filtering function becomes redundant, the device becomes larger, and this leads to an increase in manufacturing costs.

[0008] Therefore, an inverter device is provided that has an AC input terminal for a control power supply in addition to an AC input terminal for a main circuit, and that can reduce the size of the configuration required for the noise filter function. [Means for solving the problem]

[0009] The inverter device of the embodiment includes a first rectifier circuit that rectifies AC voltage received from a main circuit power supply terminal and outputs the rectified AC voltage to a main circuit DC power supply line; a second rectifier circuit that rectifies the AC voltage received from the control power supply terminal and outputs the rectified AC voltage as a control DC power supply line voltage; a diode for preventing a reverse flow of power from the control DC power supply line to the main circuit DC power supply line; an inverter main circuit connected to the main circuit DC power supply line; a control power supply circuit connected to the control DC power supply line and generating a control power supply voltage necessary for controlling the inverter main circuit; The power supply circuit includes a filter circuit disposed in a power supply path common to a power supply path from the first rectifier circuit to the control power supply circuit and a power supply path from the second rectifier circuit to the control power supply circuit. [Brief explanation of the drawings]

[0010] [Figure 1] FIG. 1 is a diagram illustrating a configuration of an inverter device according to a first embodiment. [Figure 2] FIG. 10 is a diagram illustrating a configuration of an inverter device according to a second embodiment. [Figure 3] FIG. 10 is a diagram illustrating a configuration of an inverter device according to a third embodiment. [Figure 4] FIG. 10 is a diagram illustrating a configuration of an inverter device according to a fourth embodiment. [Figure 5] FIG. 10 is a diagram illustrating a configuration of an inverter device according to a fifth embodiment. [Figure 6] 1 is a diagram showing the configuration of a conventional inverter device; DETAILED DESCRIPTION OF THE INVENTION

[0011] (First embodiment) As shown in Fig. 1, an inverter device 1 of this embodiment drives a load 3, such as a three-phase motor, by an inverter main circuit 2. The inverter main circuit 2 is configured by connecting six semiconductor switching elements, such as MOSFETs or IGBTs, in a three-phase bridge configuration. A three-phase commercial AC power supply (not shown) is connected to AC power supply terminals R, S, and T of the inverter device 1, which are connected inside the inverter device 1 to AC input terminals of a rectifier circuit 5 via a high-frequency noise filter 4. The rectifier circuit 5 is configured by connecting six diodes in a three-phase bridge configuration. A smoothing capacitor 6 and the inverter main circuit 2 are connected in parallel to the DC output terminals of the rectifier circuit 5.

[0012] The inverter main circuit 2 is switched by a control circuit 7. A control power generated by a control power circuit 8 is supplied to the control circuit 7. The inverter device 1 is provided with separate AC power supply terminals Rc and Sc so that DC power can be supplied only to the control power supply circuit 8. A single-phase commercial AC power supply (not shown) is connected to the AC power supply terminals Rc and Sc, which are connected to AC input terminals of a rectifier circuit 9 inside the inverter device 1. The DC output terminal of the rectifier circuit 9 is connected to the control power supply circuit 8 via a high-frequency noise filter 10 and a smoothing capacitor 11. The high-frequency noise filter 10 corresponds to a filter circuit.

[0013] Furthermore, in the inverter device 1, in order to supply DC power from the rectifier circuit 5 to the control power supply circuit 8, the positive output terminal of the rectifier circuit 5 is connected to the positive output terminal of the rectifier circuit 9 via a diode 12 for preventing reverse current. The negative output terminal of the rectifier circuit 5 is connected to the negative output terminal of the rectifier circuit 9. In other words, the high-frequency noise filter 10 is disposed in a power supply path common to the power supply path from the rectifier circuit 5 to the control power supply circuit 8 and the power supply path from the rectifier circuit 9 to the control power supply circuit 8. The rectifier circuits 5 and 9 correspond to the first and second rectifier circuits, respectively.

[0014] According to the inverter device 1 configured as above, the high-frequency noise filter 4 on the inverter main circuit 2 side only needs to deal with noise generated by the inverter main circuit 2. The inverter main circuit 2 is driven at a carrier frequency of, for example, about 1 kHz to 16 kHz. Therefore, the noise components generated by the inverter main circuit 2 are mainly carrier frequency components.

[0015] On the other hand, the drive frequency of the switching transistor (not shown) that constitutes the control power supply circuit 8 is around several hundred kHz. As such, there is a difference in the frequency band of noise to be attenuated between the inverter main circuit 2 and the control circuit 7. Therefore, by making the high-frequency noise filter 4 on the main circuit side compatible with only the noise generated by the inverter main circuit 2, the design can be optimized, and the inverter device 1 can be designed to be smaller and at lower cost than before.

[0016] (Second and third embodiments) Hereinafter, the same parts as those in the first embodiment will be assigned the same reference numerals and their explanation will be omitted, and only the different parts will be explained. An inverter device 1A of a second embodiment shown in Fig. 2 has terminals T1 to T4 for making the high-frequency noise filter 10 detachable as an option selected by the user. Similarly, an inverter device 1B of a third embodiment shown in Fig. 3 also makes the high-frequency noise filter 4 detachable from the outside as an option selected by the user. When the high-frequency noise filter 4 is removed, terminals T1-T3 and terminals T2-T4 are short-circuited with a short bar or the like.

[0017] (Fourth and fifth embodiments) An inverter device 13 of a fourth embodiment shown in Fig. 4 has a configuration in which an AC reactor 14 and a DC reactor 15 are arranged as filters for dealing with low frequencies instead of the high-frequency noise filters 4 and 10 of the inverter device 1. An inverter device 16 of a fifth embodiment shown in Fig. 5 has a configuration in which the AC reactor 14 is eliminated and a DC reactor 17 is arranged between the rectifier circuit 5 and the smoothing capacitor 6. The DC reactor 15 corresponds to a filter circuit.

[0018] The fourth and fifth embodiments are particularly effective when the inverter capacity is relatively small and a small-capacity film capacitor is used as the smoothing capacitor 6 of the inverter main circuit 2, as in Japanese Patent No. 4851183 and Japanese Patent No. 5175452. Even when a small-capacity film capacitor is used as the smoothing capacitor 6, a large-capacity element is required for the smoothing capacitor 11 on the control power supply circuit 8 side.

[0019] For this reason, when the power supply to the inverter main circuit 2 is cut off and power is supplied only to the control power supply circuit 8, the proportion of harmonic components in the power supply current becomes relatively high. Therefore, the DC reactor 15 used as a harmonic countermeasure can have a small current rating, but needs to have a relatively large inductance.

[0020] On the other hand, when power is also supplied from the power supply on the inverter main circuit 2 side to the control power supply circuit 8, the proportion of harmonic components caused by the large-capacity smoothing capacitor 11 of the control power supply circuit 8 becomes relatively large compared to the harmonic components caused by the small-capacity smoothing capacitor 6 in the power supply current. For this reason, by providing a DC reactor 15 dedicated to the control power supply circuit 8, it becomes possible to optimally design the AC reactor 14 or DC reactor 17 on the inverter main circuit 2 side.

[0021] (Other embodiments) The diode 12 for preventing reverse current may be disposed between the negative power supply lines. In the fourth and fifth embodiments, a high-frequency noise filter may be disposed together with the reactor. In the fourth and fifth embodiments, similarly to the second and third embodiments, each reactor may be made detachable as an option. Although several embodiments of the present invention have been described, these embodiments are presented as examples and are not intended to limit the scope of the invention. These novel embodiments can be embodied in various other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their modifications are included within the scope and spirit of the invention, and are also included in the scope of the invention and its equivalents as defined in the claims. [Explanation of symbols]

[0022] In the drawings, 1, 1A, and 1B indicate an inverter device, 2 indicates an inverter main circuit, 3 indicates a load, 4 indicates a high-frequency noise filter, 5 indicates a rectifier circuit, 6 indicates a smoothing capacitor, 7 indicates a control circuit, 8 indicates a control power supply circuit, 9 indicates a rectifier circuit, 10 indicates a high-frequency noise filter, 11 indicates a smoothing capacitor, 12 indicates a diode, 13 indicates an inverter device, 14 indicates an AC reactor, 15 indicates a DC reactor, 16 indicates an inverter device, and 17 indicates a DC reactor.

Claims

1. a first rectifier circuit that rectifies an AC voltage received from a main circuit power supply terminal and outputs the rectified AC voltage to a main circuit DC power supply line; a second rectifier circuit that rectifies the AC voltage received from the control power supply terminal and outputs the rectified AC voltage as a control DC power supply line voltage; a diode for preventing a reverse flow of power from the control DC power supply line to the main circuit DC power supply line; an inverter main circuit connected to the main circuit DC power supply line; a control power supply circuit connected to the control DC power supply line and generating a control power supply voltage necessary for controlling the inverter main circuit; an inverter device comprising: a filter circuit disposed in a power supply path common to a power supply path from the first rectifier circuit to the control power supply circuit and a power supply path from the second rectifier circuit to the control power supply circuit.

2. 2. The inverter device according to claim 1, wherein the filter circuit is configured to be detachable according to a user's selection.

3. the control power supply circuit is a switching power supply circuit, 3. The inverter device according to claim 1, wherein the filter circuit has a filter characteristic that reduces noise generated in association with a switching operation of the control power supply circuit.

4. a smoothing capacitor disposed in a power supply path common to a power supply path from the first rectifier circuit to the control power supply circuit and a power supply path from the second rectifier circuit to the control power supply circuit; 3. The inverter device according to claim 1, wherein the filter circuit is a reactor having a characteristic of reducing noise generated due to the smoothing capacitor.

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