Inverter Unit

Abstract

Provide an inverter unit that can handle a wide variety of input voltages. 【Solution means】The inverter unit 10 converts a DC input voltage into a three-phase AC output voltage. The inverter unit 10 includes a three-wire first input section 20 capable of connecting the DC of the first input voltage, a first rectifying section 22 connected to the first input section 20, a three-wire second input section 30 capable of connecting the DC of the first input voltage, and a second rectifying section 32 that is connected to the second input section 30 and is connected to the first rectifying section 22 via the neutral point 0. The inverter unit 10 can connect the DC of a second input voltage different from the first input voltage across both the first input section 20 and the second input section 30, and can input the second input voltage.

Description

Technical Field

[0001] This invention relates to an inverter unit.

Background Art

[0002] An inverter device that converts an input DC voltage into an AC voltage has been proposed (see, for example, Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] The device of Patent Document 1 is for converting a specific input voltage, and has the drawback that the type of input voltage is limited.

[0005] In view of the above problems in the prior art, the present invention is proposed to preferably solve these problems, and an object thereof is to provide an inverter unit capable of handling a wide variety of input voltages.

Means for Solving the Problems

[0006] A first aspect of the inverter unit according to the present invention is an inverter unit that converts a DC input voltage into a three-phase AC output voltage, comprising a three-wire first input section connectable to the DC of the first input voltage, a first rectifying section connected to the first input section, a three-wire second input section connectable to the DC of the first input voltage, a second rectifying section connected to the second input section and connected to the first rectifying section via a neutral point. It is essential that a DC of a second input voltage different from the first input voltage can be connected across both the first input section and the second input section, and the second input voltage can be inputted.

[0007] A second aspect of the inverter unit according to the present invention is, in the first aspect, the first rectifying section has a first rectifying circuit connected to the first input section, and a first smoothing circuit connected to the first rectifying circuit. The second rectifying section may have a second rectifying circuit connected to the second input section and connected to the first rectifying circuit via a neutral point, and a second smoothing circuit connected to the second rectifying circuit and connected to the first smoothing circuit via a neutral point.

[0008] A third aspect of the inverter unit according to the present invention is, in the first aspect or the second aspect, at least one of the first input section and the second input section may have a back electromotive force protection section provided between two of the three lines.

Advantages of the Invention

[0009] According to the inverter unit of the present invention, a plurality of types of voltages can be inputted.

Brief Description of the Drawings

[0010]

Figure 1

Figure 2

Figure 3

Figure 4

Embodiments for Carrying Out the Invention

[0011] Next, a preferred embodiment of the inverter unit according to the present invention will be described below with reference to the accompanying drawings. It should be noted that the embodiments and drawings described below illustrate a part of the embodiments of the present invention, and are not used for the purpose of limiting to these configurations, and can be appropriately changed without departing from the gist of the present invention.

[0012] As shown in FIG. 1, an inverter unit 10 according to an embodiment includes a first input unit 20 connectable to a first power supply 50A that supplies direct current of a first input voltage, and a second input unit 30 provided in parallel with the first input unit 20 and connectable to the first power supply 50A. The inverter unit 10 includes a first rectifier unit 22 connected to the first input unit 20, and a second rectifier unit 32 provided in parallel with the first rectifier unit 22 and connected to the second input unit 30. The inverter unit 10 is connectable to a second power supply 50B that supplies direct current of a second input voltage different from the first power supply 50A that supplies direct current of the first input voltage, and passes it to the first input unit 20 and the second input unit 30 (see FIG. 2). Further, the inverter unit 10 includes an inverter 12 connected to both the first rectifier unit 22 and the second rectifier unit 32, an output filter 14 having a coil 14a and a filter capacitor 14b connected to the inverter 12, and an output unit 16 connected to the output filter 14, and outputs three-phase alternating current of a predetermined output voltage from the output unit 16. Furthermore, the inverter unit 10 includes a control unit 18 that performs various controls of the inverter unit 10.

[0013] The inverter unit 10 converts the DC input voltage input from the power supplies 50A and 50B into a three-phase AC output voltage. As the first input voltage of the first power supply 50A, for example, 200V to 230V can be input. In this case, as the second input voltage of the second power supply 50B, for example, 400V to 460V may be input. Thus, the second input voltage may be set to about twice the first input voltage. When the first input voltage is 200V to 230V or the second input voltage is 400V to 460V, the output voltage is set to, for example, three-phase 200V called power. Also, as the first input voltage of the first power supply 50A, for example, 400V to 460V can be input. In this case, as the second input voltage of the second power supply 50B, for example, 800V to 920V may be input. When the first input voltage is 400V to 460V or the second input voltage is 800V to 920V, the output voltage is set to, for example, three-phase 380V to three-phase 400V.

[0014] Examples of the power supplies 50A and 50B for inputting the input voltage include a power generation device, a storage battery, and a commercial power supply. The power generation device is not limited to one that drives a power generation body by an engine or the like to generate power, and examples include a solar power generation device and other devices that generate power. The power supplies 50A and 50B are not limited to being directly connected to the first input section 20 and the second input section 30, and the power supplies 50A and 50B may be connected to the first input section 20 and the second input section 30 via a converter such as a DC-DC converter or an AC-DC converter. For example, when the power supplies 50A and 50B are single-phase AC commercial power supplies, the power supplies 50A and 50B are connected to the first input section 20 and the second input section 30 via an AC-DC converter.

[0015] Each of the first input unit 20 and the second input unit 30 has three lines including a U-phase terminal, a V-phase terminal, and a W-phase terminal, and the terminals of the first input unit 20 and the terminals of the second input unit 30 are provided on a terminal block 40 arranged in the inverter unit 10. The inverter unit 10 can connect the first power supply 50A to each of the first input unit 20 and the second input unit 30. In the inverter unit 10, when the first input voltage is input, the same first input voltage is input to each of the first input unit 20 and the second input unit 30. When the first input voltage is input in the inverter unit 10 according to the embodiment, the first power supply 50A is connected to the first input unit 20, and another first power supply 50A different from the first power supply 50A connected to the first input unit 20 is connected to the second input unit 30. In the case of direct current, the first power supply 50 may be connected to any two of the U-phase terminal, the V-phase terminal, and the W-phase terminal in the first input unit 20, and the same applies to the second input unit 30.

[0016] As shown in FIG. 2, the inverter unit 10 can connect the second power supply 50B across both the first input unit 20 and the second input unit 30. Specifically, in the inverter unit 10, the second power supply 50B is connected to one of the U-phase terminal, the V-phase terminal, and the W-phase terminal in the first input unit 20 and to one of the U-phase terminal, the V-phase terminal, and the W-phase terminal in the second input unit 30, so that direct current can be input using both the first input unit 20 and the second input unit 30. In this way, the inverter unit 10 connects one second power supply 50B using both the first input unit 20 and the second input unit 30 provided in parallel, so that even if the input voltage is a high voltage, the load on circuits such as the first rectifying unit 22 and the second rectifying unit 32 can be reduced, or the voltage setting of circuits such as the first rectifying unit 22 and the second rectifying unit 32 can be made smaller, and the like.

[0017] The first rectifying section 22 and the second rectifying section 32 are for rectifying the direct current input from the power supplies 50A and 50B into a stable direct current voltage with less pulsation. In the inverter unit 10, the first rectifying section 22 and the second rectifying section 32 are provided in parallel corresponding to the first input section 20 and the second input section 30. Also, the first rectifying section 22 and the second rectifying section 32 are connected in series with each other through the neutral point 0, and when the first power supply 50A is connected to each of the first input section 20 and the second input section 30 or when the second power supply 50B is connected across both the first input section 20 and the second input section 30, the current is rectified in the first rectifying section 22 and the second rectifying section 32.

[0018] The first rectifying section 22 includes a first rectifying circuit 24 connected to the first input section 20 and a first smoothing circuit 26 connected to the first rectifying circuit 24. The second rectifying section 32 includes a second rectifying circuit 34 connected to the second input section 30 and a second smoothing circuit 36 connected to the second rectifying circuit 34. The second rectifying circuit 34 is provided in parallel with the first rectifying circuit 24. Also, the second smoothing circuit 36 is provided in parallel with the first smoothing circuit 26. The first rectifying circuit 24 and the second rectifying circuit 34 are connected in series with each other through the neutral point 0, and when the first power supply 50A is connected to each of the first input section 20 and the second input section 30 or when the second power supply 50B is connected across both the first input section 20 and the second input section 30, the current is rectified in the first rectifying circuit 24 and the second rectifying circuit 34. Similarly, the first smoothing circuit 26 and the second smoothing circuit 36 are connected in series with each other through the neutral point 0, and when the first power supply 50A is connected to each of the first input section 20 and the second input section 30 or when the second power supply 50B is connected across both the first input section 20 and the second input section 30, the current is smoothed in the first smoothing circuit 26 and the second smoothing circuit 36.

[0019] The first rectifier circuit 24 and the second rectifier circuit 34 include rectifier thyristors 24a, 34a and rectifier diodes 24b, 34b, and the rectifier thyristors 24a, 34a are controlled by the control unit 18. More specifically, the rectifier thyristors 24a, 34a operate by being energized to a gate input unit 42 (see FIG. 3) provided in the control unit 18. The gate input unit 42 is energized based on a signal output after the power supply of a power supply circuit (not shown) provided in the control unit 18 is established. That is, the first rectifier circuit 24 and the second rectifier circuit 34 operate after the power supply of the power supply circuit is established, and energize the inverter 12 in a state where a DC voltage is established in the inverter 12. According to the first rectifier circuit 24 and the second rectifier circuit 34 of the embodiment, since the inverter 12 is not energized from the first rectifier circuit 24 and the second rectifier circuit 34 in a state where the DC voltage is not established in the inverter 12, the possibility of damaging the inverter 12 can be reduced. The first smoothing circuit 26 and the second smoothing circuit 36 include smoothing capacitors 26a, 36a, absorb the DC ripple rectified by the first rectifier circuit 24 and the second rectifier circuit 34, and smooth the DC.

[0020] As shown in FIGS. 1 and 2, in the inverter unit 10, at least one of the first input unit 20 and the second input unit 30 has a back electromotive force protection unit 44 provided between two of the three lines. In the embodiment, the back electromotive force protection unit 44 is provided in both the first input unit 20 and the second input unit 30. The back electromotive force protection unit 44 may be provided in any one of between the U-phase line and the V-phase line, between the U-phase line and the W-phase line, and between the V-phase line and the W-phase line (embodiment), or may be provided in all between these lines. The back electromotive force protection unit 44 includes a diode 44a. In the embodiment, the diode 44a is incorporated in the terminal block 40, and by simply connecting the power supplies 50A, 50B to the terminals of the terminal block 40, the back electromotive force (surge) can be absorbed by the diode 44a to protect the power supplies 50A, 50B connected to the first input unit 20 and the second input unit 30.

[0021] The inverter 12 according to the embodiment is connected to the first rectifying unit 22 and the second rectifying unit 32. In the embodiment, one inverter 12 is provided for two systems of the first rectifying unit 22 and the second rectifying unit 32. The inverter 12 has an IPM (Intelligent Power Module) and is controlled by a control unit 18. The inverter 12 is formed by modularizing a plurality of IGBTs (Insulated Gate Bipolar Transistors) 12a (see FIG. 4), which are power semiconductors. The IGBT 12a has a gate for converting the DC converted by the first rectifying unit 22 and the second rectifying unit 32 into AC by turning on and off the DC. Further, the inverter 12 includes a gate control element (gate driver) for controlling the on / off of the gate of the IGBT 12a and a protection element for detecting an abnormality of the IGBT 12a and maintaining safety (both not shown).

[0022] The control unit 18 has a microcomputer (not shown). The control unit 18 receives the detected voltage of the DC rectified by the first rectifying unit 22 and the second rectifying unit 32, the detected voltage of the DC input to the inverter 12, etc. Further, signals such as various commands such as reset, power frequency selection, voltage adjustment (regulator), and substrate temperature detection operated by an operation panel (not shown) are input to the control unit 18. The control unit 18 starts or stops the on / off operation of the gate control element by outputting an operation signal to the IPM in the inverter 12 (IGBT 12a). Further, the control unit 18 controls the gate input unit 42 to turn on and off the rectifying thyristors 24a and 34a in the first rectifying circuit 24 and the second rectifying circuit 34.

[0023] When the above-described inverter unit 10 is connected to the first power supply 50A, the DC of the first input voltage input from each of the first input unit 20 and the second input unit 30 can be converted into a three-phase alternating current of a predetermined output voltage and output by passing through the rectifying units 22, 32 and the inverter 12. Further, since the first rectifying unit 22 and the second rectifying unit 32 of the inverter unit 10 are connected via the neutral point 0, when the second power supply 50B is connected to both the first input unit 20 and the second input unit 30, the DC of the second input voltage different from the first input voltage can be converted into a three-phase alternating current of a predetermined output voltage and output by passing through the rectifying units 22, 32 and the inverter 12. Thus, the inverter unit 10 can input two types of input voltages by changing the connection method to the first input unit 20 and the second input unit 30. According to the inverter unit 10, since there are two types of inputtable input voltages, the types of power supplies 50 that can be supported can be increased, and the usability can be improved.

[0024] (Modified Example) Not limited to the above-described matters, for example, the following may be adopted. Note that the present invention is not limited to the specific descriptions of the embodiments and the following modified examples.

[0025] Not limited to directly connecting the power supply to the first input unit and / or the second input unit as in the embodiment, a converter that converts the current of the power supply, such as a DC-DC converter or an AC-DC converter, may be connected to the first input unit and / or the second input unit.

Explanation of Reference Numerals

[0026] 10 Inverter unit, 20 First input unit, 22 First rectifying unit, 24 First rectifying circuit, 26 First smoothing circuit, 30 Second input unit, 32 Second rectifying unit, 34 Second rectifying circuit, 36 Second smoothing circuit, 44 Back electromotive force protection unit, 0 Neutral point

Claims

1. An inverter unit that converts a DC input voltage into a three-phase AC output voltage, a first input section having three wires to which a direct current of a first input voltage can be connected; A first rectification unit connected to the first input unit; a three-wire second input section capable of connecting a direct current of the first input voltage; a second rectification unit connected to the second input unit and connected to the first rectification unit via a neutral point; A direct current of a second input voltage different from the first input voltage can be connected to both the first input section and the second input section, and the second input voltage can be input. An inverter unit characterized by:

2. The first rectification unit is a first rectifier circuit connected to the first input; a first smoothing circuit connected to the first rectifier circuit; The second rectification unit is a second rectifier circuit connected to the second input port and connected to the first rectifier circuit via a neutral point; 2. The inverter unit according to claim 1, further comprising: a second smoothing circuit connected to the second rectifier circuit and connected to the first smoothing circuit via a neutral point.

3. 3. The inverter unit according to claim 1, wherein at least one of the first input section and the second input section has a back electromotive force protection section provided between two of the three wires.

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