Power generation system and power converter

Abstract

To drive an electric motor using three-phase AC power as an operation power at the time of power failure of an external power supply which is a supply source of the three-phase AC power without requiring a large cost.SOLUTION: The power generation system 1A drives an electric motor 40 driven by three-phase AC power supplied from an external power source 30 at the time of power failure of the external power source 30. A power generation system 1A includes a power generator 20 that generates single-phase AC power, and a power converter 10 that converts the single-phase AC power generated by the power generator 20 into three-phase AC power and outputs the three-phase AC power to a motor 40. The power converter 10 includes a converter unit that converts single-phase AC power into DC power, a filter unit that smoothes the DC power converted by the converter unit, an inverter unit that converts the DC power smoothed by the filter unit into three-phase AC power, and a reactor provided between the converter unit and the inverter unit and connected in parallel to the inverter unit.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to a power generation system and a power converter. [Background technology]

[0002] In buildings such as apartment buildings or tenant buildings, multiple tenants live or run their businesses separately and independently. In these types of buildings, water for daily use and other purposes is sometimes supplied to each tenant as follows: A water tank is installed in the basement or other room of the building to store water supplied from water pipes managed by the local government or other organization. The water stored in the water tank is pumped up to a water storage tank installed on the building's roof or other location using a pump. The water stored in the water storage tank is supplied to each tenant through water pipes installed within the building by utilizing the potential energy of gravity. In other buildings, water may be supplied directly to each tenant using pump pressure.

[0003] In buildings, pumps that pump water from a water receiving tank to a water storage tank or supply water using direct pressure are generally driven by electric motors that receive operating power from an external power source such as a commercial AC power source. Therefore, if a disaster such as an earthquake causes a long-term power outage in the external power source, the water supply to each resident in the building will be disrupted. Therefore, in preparation for emergencies such as a power outage in the external power source, it is possible to install power generation equipment in the building that generates the operating power for the electric motor that drives the pump (for example, Patent Document 1). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2013-60725 Summary of the Invention [Problem to be solved by the invention]

[0005] In recent years, inexpensive generators have become commercially available, but the power generated by these generators is often single-phase AC power. Meanwhile, the operating power of motors that drive pumps used to supply water to buildings is often three-phase AC power, and the single-phase AC power generated by inexpensive generators cannot drive these motors. While installing a generator that generates three-phase AC power as an emergency power generation facility is an option, installing such a generator requires significantly more money than installing a generator that generates single-phase AC power.

[0006] The present disclosure has been made in consideration of the above-mentioned problems, and aims to provide a technology that enables an electric motor that uses three-phase AC power as its operating power to be driven without incurring a large amount of expense during a power outage of an external power source that supplies the three-phase AC power. [Means for solving the problem]

[0007] In order to solve the above-described problems, a power generation system according to a first aspect of the present disclosure includes a generator that generates single-phase AC power to provide operating power to an electric motor driven by first three-phase AC power supplied from an external power source during a power outage of the external power source, and a power converter that converts the first single-phase AC power, which is at least a portion of the single-phase AC power, into second three-phase AC power and outputs the second three-phase AC power to the electric motor. The power converter includes a converter unit, a filter unit, and an inverter unit. The converter unit converts the first single-phase AC power into DC power. The filter unit smoothes the DC power converted by the converter unit. The inverter unit converts the DC power smoothed by the filter unit into the second three-phase AC power. The filter unit includes a reactor connected in parallel to the inverter unit.

[0008] In the power generation system of the first aspect, a generator that generates single-phase AC power, i.e., an inexpensive generator, can be used to generate three-phase AC power that serves as the operating power for the electric motor, making it possible to drive the electric motor during a power outage in the external power source that supplies the operating power to the electric motor without incurring significant costs.

[0009] A more preferred power generation system of a second aspect is the power generation system of the first aspect, including: a phase converter to which second single-phase AC power, which is the difference between the single-phase AC power generated by the generator and the first single-phase AC power, is input; and a second power converter to which the second single-phase AC power is input via the phase converter, converts the input second single-phase AC power into third three-phase AC power, and outputs the third three-phase AC power to the electric motor. According to the power generation system of the second aspect, even if one power converter cannot cover the operating power of the electric motor, it is possible to drive the electric motor during a power outage of an external power supply.

[0010] In order to solve the above problems, a power converter according to a third aspect of the present disclosure includes a converter unit, a filter unit, and an inverter unit. The converter unit converts supplied single-phase AC power into DC power. The filter unit smoothes the DC power converted by the converter unit. The inverter unit converts the DC power smoothed by the filter unit into three-phase AC power. The filter unit includes a reactor connected in parallel to the inverter unit. As with the first aspect, the power converter according to the third aspect makes it possible to drive an electric motor without incurring significant costs during a power outage of an external power supply that supplies three-phase AC power as operating power to the electric motor. [Brief explanation of the drawings]

[0011] [Figure 1] 1 is a diagram illustrating a configuration example of a power generation system 1A according to an embodiment of the present disclosure. [Figure 2] 1 is a diagram showing an example of the configuration of a power converter 10 included in a power generation system 1A. [Figure 3] FIG. 10 is a diagram showing an example of the configuration of a power generation system 1B according to a modified example (3). DETAILED DESCRIPTION OF THE INVENTION

[0012] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. (A. Embodiment) FIG. 1 is a diagram illustrating an exemplary configuration of a power generation system 1A according to an embodiment of the present disclosure. The power generation system 1A is a system for driving an electric motor 40, which is driven by 200V three-phase AC power supplied from an external power source 30, such as a commercial AC power source, during a power outage of the external power source 30. In this embodiment, the electric motor 40 pumps water from a water tank in the basement of a building to a water storage tank on the roof of the building, or drives a pump 50 to supply water to each resident. The power generation system 1A is retrofitted to the building as a precaution against a power outage of the external power source 30. The distribution board 60 in FIG. 1 is an existing distribution board in the building. During normal operation, when there is no power outage of the external power source 30, the distribution board 60 supplies three-phase AC power to a pump control panel 50a as operating power. The three-phase AC power supplied from the external power source 30 to the electric motor 40 is an example of the first three-phase AC power of the present disclosure. Note that the power consumption of the electric motor 40 in this embodiment is 5.5 kW or less.

[0013] As shown in FIG. 1 , the power generation system 1A includes a power converter 10 and a generator 20 that can supply power in place of an external power supply 30. The generator 20 generates 200V single-phase AC power by using, for example, propane gas as a heat source. The heat source of the generator 20 is not limited to propane gas and may be a fossil fuel such as gasoline. In the event of a power outage in the external power supply 30, a power supply changeover switch 80 is switched to supply the single-phase AC power generated by the generator 20 to the power converter 10. The power converter 10 converts the single-phase AC power generated by the generator 20 into 200V three-phase AC power and outputs it to the electric motor 40 via the power supply changeover switch 80 and the manual changeover switch 80. In this embodiment, the single-phase AC power shared from the generator 20 to the power converter 10 is an example of a first single-phase AC power in the present disclosure. The three-phase AC power output from the power converter 10 to the electric motor 40 is an example of a second three-phase AC power in the present disclosure.

[0014] Fig. 2 is a diagram showing an example of the configuration of the power converter 10. As shown in Fig. 2, the power converter 10 includes a converter unit 100, a filter unit 110, and an inverter unit 120. Single-phase AC power generated by a generator 20 is input to the converter unit 100. The converter unit 100 converts the single-phase AC power input from the generator 20 into DC power and outputs it. As the converter unit 100, for example, a single-phase full-wave rectifier circuit using a diode bridge or the like is appropriately adopted.

[0015] The filter unit 110 is provided between the converter unit 100 and the inverter unit 120. The filter unit 110 includes a reactor (a passive element using an inductor) 110a connected in parallel to the inverter unit 120. The filter unit 110 smoothes pulsations in the DC power output from the converter unit 100 and outputs the smoothed power to the inverter unit 120. Although not shown in detail in FIG. 2 , the filter unit 110 may include a capacitor connected in parallel to the inverter unit 120.

[0016] The inverter unit 120 converts the DC power smoothed by the filter unit 110 into three-phase AC power and outputs it to the electric motor 40. As the inverter unit 120, for example, an existing inverter circuit such as a voltage-type inverter circuit or a current-type inverter circuit is appropriately adopted.

[0017] In the power generation system 1A of this embodiment, the generator 20 that generates single-phase AC power, i.e., an inexpensive generator, can be used to drive the motor 40 that operates on three-phase AC power, making it possible to drive the motor 40 during a power outage of the external power source 30 without incurring significant costs. When the power outage is resolved, the power source changeover switch 70 automatically switches over to the external power source 30 as the power supply source. The manual changeover switch 80 is provided to ensure safety, and by operating the manual changeover switch 80, it is possible to control on / off the supply of power to the motor 40.

[0018] (B. Transformation) The above-described embodiment may be modified as follows. (1) In the above embodiment, the electric motor 40, to which operating power is supplied by the power generation system 1A during a power outage of the external power source 30, pumps water from a water tank provided in the basement or the like of the building to a water storage tank provided on the roof of the building, or drives a pump to supply water to each resident. However, the electric motor to which operating power is supplied by the power generation system 1A is not limited to an electric motor that drives a pump, and may be any electric motor that is driven by three-phase AC power.

[0019] (2) In the above embodiment, the power generation system 1A is installed in a building, but it may be installed in a building other than a shared building such as a single store. Furthermore, the installation of the power generation system 1A is not limited to being retrofitted to the building, and the power generation system 1A may be constructed when the building is constructed.

[0020] (3) In the above embodiment, the power consumption of the electric motor 40 is 5.5 kW or less. However, if the power consumption of the electric motor 40 is 3.7 kW or more, as shown in FIG. 3 , a power generation system 1B may be configured using a generator 20, power converters 10A and 10B, and a phase converter 90 such as a digital phase shifter. The configurations of the power converters 10A and 10B are the same as the configuration of the power converter 10. In the power generation system 1B, a portion of the single-phase AC power generated by the generator 20 is input to the power converter 10A. The portion of the single-phase AC power generated by the generator 20 is an example of the first single-phase AC power in the present disclosure. Then, the portion of the single-phase AC power generated by the generator 20, i.e., the difference between the single-phase AC power and the single-phase AC power input to the power converter 10A, is input to the phase converter 90. The single-phase AC power input from the generator 20 to the phase converter 90 is an example of the second single-phase AC power in the present disclosure.

[0021] Single-phase AC power (i.e., second single-phase AC power) is input to power converter 10B via phase converter 90. Power converter 10B converts the input single-phase AC power into 200V three-phase AC power and outputs it to electric motor 40. Power converter 10B is an example of the second power converter in the present disclosure. The three-phase AC power output by power converter 10B is an example of the third three-phase AC power in the present disclosure. According to power generation system 1B shown in FIG. 3, even if one power converter 10 is not enough to cover the operating power of electric motor 40, it is possible to drive electric motor 40 during a power outage of external power supply 30.

[0022] (4) In the above embodiment, the reactor 110a, which is provided between the converter unit 100 and the inverter unit 120 and connected in parallel to the inverter unit 120, is included in the filter unit 110. However, the reactor 110a may be provided separately from the filter unit 110. In an aspect in which the reactor 110a is provided separately from the filter unit 110, the filter unit 110 may be built in the output stage of the converter unit 100 or the input stage of the inverter unit 120. [Explanation of symbols]

[0023] 1A, 1B...power generation system, 10, 10A, 10B...power converter, 20...generator, 30...external power supply, 40...electric motor, 50...pump, 60...distribution board, 70...power supply changeover switch, 80...manual changeover switch, 90...phase converter, 100...inverter section, 110...filter section, 110a...reactor, 120...converter section.

Claims

1. 1. A power generation system that supplies operating power to an electric motor driven by first three-phase AC power supplied from an external power supply during a power outage of the external power supply, a generator that generates single-phase AC power; a power converter that converts first single-phase AC power, which is at least a part of the single-phase AC power generated by the generator, into second three-phase AC power and outputs the second three-phase AC power to the electric motor; The power converter includes: a converter unit that converts the first single-phase AC power into DC power; a filter unit that smoothes the DC power converted by the converter unit; an inverter unit that converts the DC power smoothed by the filter unit into the second three-phase AC power; a reactor provided between the converter unit and the inverter unit and connected in parallel to the inverter unit, A power generation system characterized by:

2. a phase converter to which second single-phase AC power, which is the difference between the single-phase AC power generated by the generator and the first single-phase AC power, is input; a second power converter that receives the second single-phase AC power via the phase converter, converts the input second single-phase AC power into third three-phase AC power, and outputs the third three-phase AC power to the electric motor; The power generation system of claim 1 , comprising:

3. a converter unit that converts the supplied single-phase AC power into DC power; a filter unit that smoothes the DC power converted by the converter unit; an inverter unit that converts the DC power smoothed by the filter unit into three-phase AC power, the filter unit includes a reactor connected in parallel to the inverter unit. A power converter comprising:

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