JP2019071702A - Power conversion device and power conversion method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a power conversion device and a power conversion method capable of suppressing an influence on another electronic device in a power generation device to which another electronic device is connected. SOLUTION: A power conversion device 70 has an inverter circuit 72 having switching elements 72a to 72d for converting a DC voltage of a DC power generated by a fuel cell 1 into an AC voltage, forming a closed circuit, and the inverter circuit 72. When the power waveform of the AC voltage output to the outside from the closed circuit of the above contains a harmonic component, the frequency control unit 103 that raises the switching frequency of the switching elements 72a to 72d by a predetermined value is provided. [Selection diagram] FIG. 5

Description

  The present invention relates to a power converter and a power conversion method.

Patent Document 1 discloses a power conversion apparatus that supplies DC power generated by a solar cell module to a load by linking it with a commercial power system. This power conversion device includes an inverter circuit having a switching element for converting a DC voltage of DC power generated by the solar cell module into an AC voltage, an inverter control circuit for controlling the inverter circuit, and the presence of a person around the power conversion device. And a human sensing means for sensing. When the human sensing means senses the presence of a person, the inverter control circuit controls to raise the switching frequency, and the inverter circuit switches on and off of the switching element based on the switching frequency to convert the DC voltage to the AC voltage. . Conversely, when the human sensing means does not sense the presence of a human, the inverter control circuit controls to lower the switching frequency.
As described above, in the power conversion device of Patent Document 1, when the presence of human being is detected, the switching frequency is increased although the power conversion efficiency falls, the noise performance is satisfied, and the switching frequency is not detected. Power conversion efficiency can be improved.

JP 2005-210853 A

  When another electronic device is connected to a power generation device such as a solar cell module, there is a problem that the other electronic device generates noise due to the influence of the AC voltage of the power generation device. In the power generation device of Patent Document 1, noise is controlled only by the presence or absence of human beings, and when other electronic devices are connected to the power generation device, the influence of noise and lighting flicker etc. occurs. Does not provide any technology for reducing the effects of such noise and flicker of lighting.

  Then, an object of the present invention is to provide a power conversion device and a power conversion method capable of suppressing an influence given to other electronic devices in a power generation device to which the other electronic devices are connected.

The characteristic configuration of the power conversion device according to the present invention is
An inverter circuit having a switching element for converting a DC voltage of DC power generated by the power generation apparatus into an AC voltage, and forming a closed circuit,
A frequency control unit that raises the switching frequency of the switching element by a predetermined value when a harmonic component is included in the power waveform of the AC voltage output from the closed circuit of the inverter circuit to the outside;
In providing the

  The inverter circuit of the power conversion device is a device that converts the DC voltage generated by the power generation device into an AC voltage, but the power waveform of the AC voltage after conversion is added to the generated waveform that the power conversion device is trying to generate , Harmonic components affected by the switching frequency of the inverter circuit. Then, when another electronic device other than the power generation device is connected to the power conversion device, when the AC voltage from the power generation device flows into the other electronic device while including the harmonic component, the other electronic device is a harmonic Under the influence of the component, abnormal noise may be generated, and flickering of illumination may occur.

  According to the feature configuration of the present invention, when the AC voltage output from the closed circuit of the inverter circuit to the outside includes a harmonic component, control is performed to increase the switching frequency of the inverter circuit. Since the harmonic component is generated in synchronization with the switching frequency of the inverter circuit, by raising the switching frequency, the frequency of the harmonic component is also raised. As a result, the frequency of abnormal noise generated from another electronic device approaches the outside of the audible range or the outside of the audible range due to the influence of the harmonic component. Therefore, abnormal noise becomes hard to hear to the ear, and the noise problem can be suppressed. In addition, as the frequency of the harmonic component is increased, the flickering interval of the illumination is narrowed, and the problem of the flicker can be suppressed.

  Further, the power converter described above controls the switching frequency to suppress the generation of noise due to the abnormal noise of other electronic devices connected to the power converter, the flickering of illumination, and the like. Therefore, it is not necessary for the other electronic devices to be equipped with a device for suppressing the generation of noise due to abnormal noise, flickering of illumination, etc. Furthermore, the other electronic devices need to be controlled for noise suppression and flicker suppression, etc. There is no Therefore, even when a device for noise suppression, flicker suppression, and the like and another new electronic device not having control are connected to the power conversion device, the power conversion device generates noise due to noise from the new electronic device. It is possible to suppress generation and flickering of lighting. Thereby, the freedom degree which can connect a new electronic device to a power converter device can be improved.

The further characteristic composition of the power converter concerning the present invention is
A harmonic component determination unit that determines whether a power component of the AC voltage output from the closed circuit of the inverter circuit includes a harmonic component;
When the harmonic component determination unit determines that the power waveform of the AC voltage output from the closed circuit of the inverter circuit includes a harmonic component, the frequency control unit determines the switching frequency The point is to increase by a predetermined value.

  The harmonic component determination unit can automatically determine whether the AC voltage output from the closed circuit of the inverter circuit to the outside includes a harmonic component.

The further characteristic composition of the power converter concerning the present invention is
The frequency control unit raises the switching frequency when the frequency of the harmonic component included in the AC voltage output from the closed circuit of the inverter circuit is equal to or less than a threshold.

  If the frequency of the harmonic component coming out of the closed circuit of the inverter circuit is lower than the threshold, connecting the other electronic device to the power converter causes the other electronic device to be affected by the lower frequency harmonic component. It generates sound and noise problems occur. In addition, the influence of low frequency harmonic components causes a problem of flickering of the illumination.

  According to the feature configuration of the present invention, when the frequency of the harmonic component is lower than the threshold value, the switching frequency of the inverter circuit is increased to raise the frequency of the harmonic component. As a result, noise due to abnormal noise generated from another electronic device due to the influence of harmonic components, flicker of illumination, and the like are suppressed.

The further characteristic composition of the power converter concerning the present invention is
The frequency control unit is to increase the switching frequency to a frequency outside the audible range.

  When the alternating current voltage out of the closed circuit of the inverter circuit includes a harmonic component, other electronic devices connected to the power converter may generate noise due to the influence of the harmonic component. Therefore, by raising the switching frequency to a frequency outside the audible range, it is possible to make it difficult for the user to hear abnormal noise generated from other electronic devices due to the influence of harmonic components, and to suppress noise.

The further characteristic composition of the power converter concerning the present invention is
If the power waveform of the AC voltage output from the closed circuit of the inverter circuit is not included in the power waveform of the AC voltage after the switching frequency is increased, the frequency control unit may switch the switching frequency The point is to lower by a predetermined value.

  The frequency controller lowers the switching frequency when the harmonic component is not included after controlling the switching frequency to increase the switching frequency when the power waveform of the AC voltage includes the harmonic component. By eliminating the harmonic component in the power waveform of the AC voltage, the influence of the harmonic component on other electronic devices connected to the power conversion device is eliminated, noise due to abnormal noise, flicker of illumination, etc. are generated. Hateful. In this case, the power conversion efficiency of the power conversion device can be improved by lowering the switching frequency.

The further characteristic composition of the power converter concerning the present invention is
A harmonic component determination unit that determines whether a power component of the AC voltage output from the closed circuit of the inverter circuit includes a harmonic component;
A notification unit configured to notify that the switching frequency is increased by a predetermined value when the power waveform of the AC voltage includes a harmonic component;
A setting reception unit that receives a setting of a setting frequency that can increase the switching frequency by a predetermined value after notification by the notification unit;
And further
The frequency control unit raises the switching frequency to the setting frequency accepted by the setting accepting unit when a harmonic component is included in the power waveform of the AC voltage output from the closed circuit of the inverter circuit to the outside. It is on the point.

  When an electronic device other than the power generation device is connected to the power conversion device, when the AC voltage from the power generation device flows into the other electronic device while containing the harmonic component, the other electronic device receives the influence of the harmonic component. In some cases, noise may be generated, and flickering of light may occur.

  According to the above feature configuration, when an AC voltage including a harmonic component is output from the closed circuit of the inverter circuit, notification is performed to receive a set frequency that can increase the switching frequency by a predetermined value. . By setting the switching frequency of the switching element to this set frequency, the frequency of the harmonic component also increases. As a result, the frequency of abnormal noise generated from another electronic device approaches the outside of the audible range or the outside of the audible range due to the influence of the harmonic component. This makes it difficult for the abnormal sound to be heard by the ear, and the noise problem can be suppressed. In addition, as the frequency of the harmonic component is increased, the flickering interval of the illumination is narrowed, and the problem of the flicker can be suppressed.

The further characteristic composition of the power converter concerning the present invention is
The setting receiving unit is configured to be able to receive the setting of the setting frequency in stages.

  Since the setting frequency can be adjusted stepwise, control is performed so that the switching frequency does not become excessively high, and the power conversion efficiency of the power conversion device is lowered while suppressing noise and flicker of illumination due to the influence of harmonic components. Can be suppressed.

The further characteristic composition of the power converter concerning the present invention is
If the harmonic component determination unit determines that the harmonic component is not included in the power waveform of the AC voltage output from the closed circuit of the inverter circuit after the switching frequency is increased, the notification unit Informs that the switching frequency is lowered by a predetermined value,
The setting reception unit receives setting of a setting frequency that can lower the switching frequency by a predetermined value,
The frequency control unit lowers the switching frequency to the set frequency accepted by the setting accepting unit.

  When the power waveform of the AC voltage output from the closed circuit of the inverter circuit does not include a harmonic component, other electronic devices are affected by the harmonic component and noise and flicker of illumination due to abnormal noise It becomes difficult to generate etc. In this case, the power conversion efficiency of the power conversion device can be improved by lowering the switching frequency.

The further characteristic composition of the power converter concerning the present invention is
The case where the power waveform of the AC voltage output from the closed circuit of the inverter circuit includes a harmonic component is the case where the other electronic device is connected to the power conversion device, the other electronic device Is at least either of generating abnormal noise having a frequency in the audible range under the influence of the harmonic component and generating flicker of light,
A setting reception unit that receives a setting of a setting frequency that can raise the switching frequency by a predetermined value when a power waveform of the AC voltage output from the closed circuit of the inverter circuit to the outside includes a harmonic component When,
The frequency control unit raises the switching frequency to the setting frequency accepted by the setting accepting unit.

  When another electronic device other than the power generation device is connected to the power conversion device, when the AC voltage from the power generation device flows into the other electronic device while including the harmonic component, the other electronic device has the harmonic component Under the influence, noise may be generated and flicker of lighting may occur. According to this feature configuration, when the user inputs a setting frequency capable of increasing the switching frequency by a predetermined value to the setting accepting unit based on the generation of abnormal noise, flickering of illumination, etc., the frequency control unit switches the switching frequency. To the set frequency. As a result, it is possible to suppress the noise problem by bringing the frequency of the abnormal noise generated from the other electronic device closer to the outside of the audible range or the outside of the audible range under the influence of the harmonic component. In addition, as the frequency of the harmonic component is increased, the flickering interval of the illumination is narrowed, and the problem of the flicker can be suppressed.

The further characteristic composition of the power converter concerning the present invention is
The setting receiving unit is configured to be able to receive the setting of the setting frequency in stages.

  The ability to adjust the set frequency in stages controls the switching frequency so that it does not become excessively high, and suppresses the problems such as noise and flickering of illumination due to the influence of harmonic components, while the power conversion efficiency of the power conversion device It is possible to suppress the decrease.

The characteristic configuration of the power conversion method according to the present invention is
What is claimed is: 1. A power conversion method in a power conversion device including a switching device and an inverter circuit forming a closed circuit, the power conversion method comprising:
Converting the DC voltage of the DC power generated by the power generation apparatus into an AC voltage by switching the switching element;
Increasing the switching frequency of the switching element by a predetermined value if a harmonic component is included in the power waveform of the alternating voltage output from the closed circuit of the inverter circuit to the outside;
In providing the

  Similar to the above, it is possible to suppress problems such as noise due to abnormal noise and flickering of illumination, and to improve the degree of freedom in which a new electronic device can be connected to the power conversion device.

A further characteristic configuration of the power conversion method according to the present invention is
Determining whether a power component of the AC voltage output from the closed circuit of the inverter circuit includes a harmonic component;
Notifying that the switching frequency is increased by a predetermined value when a harmonic component is included in the power waveform of the AC voltage;
Receiving, after notification, a setting of a set frequency capable of increasing the switching frequency by a predetermined value;
And further
The step of raising the switching frequency of the switching element by a predetermined value is to raise the switching frequency to the set frequency.

  Similar to the above, it is possible to suppress problems such as noise due to abnormal noise and flickering of illumination, and to improve the degree of freedom in which a new electronic device can be connected to the power conversion device.

A further characteristic configuration of the power conversion method according to the present invention is
The case where the power waveform of the AC voltage output from the closed circuit of the inverter circuit includes a harmonic component is the case where the other electronic device is connected to the power conversion device, the other electronic device Is at least either of generating abnormal noise having an audible frequency and / or generating light flicker under the influence of the harmonic component.
If a harmonic component is included in the power waveform of the AC voltage output from the closed circuit of the inverter circuit, a step of receiving a setting frequency setting that can increase the switching frequency by a predetermined value is further provided. Equipped
The step of raising the switching frequency of the switching element by a predetermined value is to raise the switching frequency to the set frequency.

  Similar to the above, it is possible to suppress problems such as noise due to abnormal noise and flickering of illumination, and to improve the degree of freedom in which a new electronic device can be connected to the power conversion device.

It is a block diagram at the time of arrange | positioning a fuel cell system to each household as a distributed power supply. It is a block diagram of a fuel cell system. FIG. 5 is an electric circuit diagram in which only a power converter is connected between a fuel cell and a commercial power system. FIG. 5 is an electric circuit diagram in which a solar power generation device is connected as another electronic device to a power conversion device connected between a fuel cell and a commercial power system. It is an electric circuit diagram of a power converter concerning an embodiment. It is an example of the flowchart which shows the frequency control flow in the power converter device which concerns on embodiment. It is an electric circuit diagram of a power converter which can receive a switching frequency from a user. It is a schematic diagram of the power converter device in which the knob adjustment member was provided.

[Embodiment]
A fuel cell system having a power converter according to an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a configuration diagram when a fuel cell system is disposed in each home as a distributed power supply.

(1) Configuration of a Household Equipped with a Fuel Cell System Each household 10 is provided with a fuel cell system 20 equipped with a power generation unit 20a including a fuel cell 1 (power generator) for generating electric power and a hot water storage tank 20b. . Moreover, as equipment used in each home 10, as shown in FIG. 1, for example, hot water supply equipment such as a water heater 10a and a bath 10b, and household appliances such as an air conditioner 10c, a light 10d, a television 10e and a refrigerator 10f Equipment and the like. The hot water supply equipment such as the hot water heater 10a and the bath 10b is connected to the hot water storage tank 20b of the fuel cell system 20, and receives supply of hot water from the hot water storage tank 20b.

  Each home 10 not only receives the supply of the generated power generated by the fuel cell system 20, but is also connected to the commercial power system 30 to receive the supply of the commercial power. Therefore, home electric appliances such as the air conditioner 10c, the lighting 10d, the television 10e and the refrigerator 10f of each home 10 are at least either of the generated power from the power generation unit 20a of the fuel cell system 20 and the commercial power from the commercial power system 30. It is driven by the supply of power from the head.

(2) Fuel Cell System The fuel cell system 20 will be described below. FIG. 2 is a block diagram of a fuel cell system.
The fuel cell system 20 includes the power generation unit 20a and the hot water storage tank 20b as described above. The power generation unit 20a basically includes a fuel cell 1 that generates electricity by causing a reaction between fuel gas and oxygen gas, a heat exchanger 2 that recovers the heat of exhaust gas discharged from the fuel cell 1, and the heat exchanger 2 A water purifier 4 for recovering and purifying condensed water from exhaust gas after heat recovery, a reforming water tank 5 for recovering condensed water purified by the water purifier 4, and reforming water independently A water supply unit 6 capable of supplying water to the water tank 5 is provided. The fuel cell system 20 is operated under the control of an operation control unit (not shown).
Hereinafter, the configuration of each part of the fuel cell system 20 will be described.

  The fuel cell 1 includes a reformer 12 that steam-reforms the raw fuel (for example, the city gas 13A) supplied via the raw fuel flow path 11 to generate a fuel gas, and the fuel gas flow path 13. The anode 15 to which the fuel gas generated by the reformer 12 is supplied, the cathode 16 to which air (an example of oxygen gas) is supplied via the air flow path 14, and the anode 15 and the cathode 16 And an electrolyte 17 for generating electric power by reacting the supplied fuel gas and air. Then, the fuel cell 1 includes a combustion unit 18 to which the fuel gas and air discharged after being used for the power generation reaction from the anode 15 and the cathode 16 are supplied, respectively, and remains in the fuel gas by the combustion unit 18 The fuel component is burned to generate an exhaust gas. As described later, water is supplied to the reformer 12 from the reforming water tank 5 via the water supply passage 52, and the reformer 12 is supplied from the reforming water tank 5. Water is used to perform steam reforming of raw fuel.

  The exhaust gas discharged from the fuel cell 1 is supplied to the heat exchanger 2 through the exhaust gas supply passage 21, and the exhaust gas after heat recovery is exhausted through the exhaust gas discharge passage 22. Then, the hot water from the hot water storage tank 20b is supplied to the heat exchanger 2 through a circulation path 23 that circulates hot water through the hot water storage tank 20b for storing hot water and the heat exchanger 2. The heat exchanger 2 exchanges heat between the exhaust gas discharged from the fuel cell 1 and the hot and cold water. The circulation passage 23 is provided with a pump 24, a radiator 25 provided with a heat radiation fan 25a, a temperature sensor (not shown), and the like. In addition, the hot water storage tank 20b is provided with a hot water discharge passage 31 for pouring hot water in the hot water storage tank 20b, and a water supply passage 32 for supplying water to the hot water storage tank 20b according to the hot water discharge.

  The reforming water tank 5 is for recovering condensed water generated from the exhaust gas discharged from the fuel cell 1, and in the present embodiment, the condensed water is recovered from the exhaust gas after heat recovery by the heat exchanger 2. It has become. Further, in the present embodiment, the condensed water supplied to the reforming water tank 5 is purified by the water purifier 4. Specifically, the condensed water recovery passage 41 from the exhaust gas flowing through the exhaust gas discharge passage 22 is purified. The condensed water is recovered to the water purifier 4 via the condensed water, and the condensed water purified by the water purifier 4 is recovered to the reforming water tank 5 via the condensed water recovery path 51. The condensed water stored in the reforming water tank 5 (and the water supplied from the water supply unit 6) can be supplied to the reformer 12 through the water supply passage 52 by the operation of the pump 53. There is. Further, the reforming water tank 5 is provided with a water level detector 54 so that the water level in the reforming water tank 5 can be detected.

  Further, water can be supplied to the reforming water tank 5 from the water supply unit 6 independently of the condensed water. Specifically, the water supply unit 6 is configured to supply tap water, and as the water injection operation, the operation control unit opens the valve 62 according to the water injection command to supply makeup water from the water supply unit 6 Water is supplied via the channel 61. Then, the water injection amount from the start of water injection operation is measured by the flow meter 63, and water injection is performed until the water injection amount reaches a predetermined target water injection amount. In addition, since tap water is likely to contain more impurities than condensed water, the water supply unit 6 can supply water to the reforming water tank 5 via the water purifier 4 in the water injection operation, and the impurities The water after removal of the water is supplied to the reforming water tank 5.

  The direct current voltage of the direct current power generated by the fuel cell 1 is converted into an alternating voltage in the following power conversion device 70 in order to interconnect with the commercial power of the commercial power system 30.

(3) Power Converter Next, the power converter 70 will be described.
Here, in the present embodiment, when another electronic device is connected to the power conversion device 70 that converts the electric power generated by the fuel cell 1, a technology capable of suppressing the influence on the electronic device such as noise and flickering of illumination. The aim is to get Therefore, first, only the power conversion device 70 is connected between the fuel cell 1 and the commercial power system 30, and the electric circuit (FIG. 3) to which no other electronic device is connected and the fuel conversion device 70 In the electric circuit (FIG. 4) to which another electronic device other than the battery 1 is connected, the occurrence of problems such as noise and flickering of illumination is examined.

(3-1) Examination of Problem Occurrence of Noise, Flicker of Lighting, etc. First, with reference to FIG. 3, noise and electric circuit in which only the power conversion device 70 is connected between the fuel cell 1 and the commercial power system 30 Investigate the occurrence of problems such as flickering of lighting. FIG. 3 is an electric circuit diagram in which only the power conversion device is connected between the fuel cell and the commercial power system. Power converter 70 is configured to use a DC voltage of the DC power generated by fuel cell system 20 as the commercial power of commercial power system 30 so as to enable interconnection operation between fuel cell system 20 and commercial power system 30. Convert to alternating voltage.

The power converter 70 is connected to the anode 15 and the cathode 16 of the fuel cell 1, and includes a booster circuit 71, an inverter circuit 72 and a smoothing circuit 73. The booster circuit 71, the inverter circuit 72 and the smoothing circuit 73 constitute a closed circuit. In FIG. 3, one end of the capacitor C1 and the output end of the reactor 73a are connected by a node N1, and the other end of the capacitor C1 and the output end of the reactor 73b are connected by a node N2. The booster circuit 71, the inverter circuit 72 and the smoothing circuit 73 are connected to the node N1 and the node N2 in the closed circuit, and the opposite side of the node N1 and the node N2 to the closed circuit is outside the closed circuit.
The booster circuit 71 boosts the DC voltage of the DC power of the fuel cell 1. The inverter circuit 72 converts the DC voltage boosted by the booster circuit 71 into an AC voltage. The smoothing circuit 73 removes noise of the AC voltage converted by the inverter circuit 72.

  The inverter circuit 72 includes switching elements 72a to 72d as shown in FIG. The switching elements 72a to 72d are made of, for example, IGBTs (Insulated Gate Bipolar Transistors). In addition, the switching elements 72a to 72d may be configured from switching transistors such as MOSFETs (metal-oxide-semiconductor field-effect transistors). Then, reflux diodes D7a to D7d are connected to the respective switching elements 72a to 72d between the collector terminal and the emitter terminal.

  The switching element 72 a and the switching element 72 b are connected in series between a pair of output ends of the booster circuit 71. That is, the collector terminal of the switching element 72a is connected to one end of the output end of the booster circuit 71, the emitter terminal of the switching element 72a and the collector terminal of the switching element 72b are connected, and the emitter terminal of the switching element 72b is the booster circuit 71. It is connected to the other end of the output end.

  Similarly, the switching element 72 c and the switching element 72 d are connected in series between a pair of output ends of the booster circuit 71. That is, the collector terminal of the switching element 72c is connected to one end of the output end of the booster circuit 71, the emitter terminal of the switching element 72c and the collector terminal of the switching element 72d are connected, and the emitter terminal of the switching element 72d is the booster circuit 71. It is connected to the other end of the output end.

  The smoothing circuit 73 includes a reactor 73a, a reactor 73b, and a capacitor C1. One end of the reactor 73a is connected between the emitter terminal of the switching element 72a and the collector terminal of the switching element 72b, and the other end is connected to one end of the capacitor C1. The reactor 73b is connected between the emitter terminal of the switching element 72c and the collector terminal of the switching element 72d, and the other end is connected to the other end of the capacitor C1. The reactor 73a, the reactor 73b, and the capacitor C1 function as a noise removal filter that smoothes the AC voltage output from the inverter circuit 72, that is, removes noise of the AC voltage.

  Such a power converter 70 operates as follows. The DC voltage of the DC power generated by the fuel cell 1 is boosted by the booster circuit 71. In the inverter circuit 72, the switching element 72a and the switching element 72d are on, and the first loop when the switching element 72b and the switching element 72c are off, and the switching element 72a and the switching element 72d are off. It operates by switching with the second loop when the switching element 72c is on. When the boosted DC voltage is input to the inverter circuit 72, it is converted into an AC voltage by switching between the first loop and the second loop at a predetermined switching frequency. The AC voltage output from the inverter circuit 72 is introduced into the smoothing circuit 73. Thus, the generated power generated by the fuel cell system 20 and the commercial power of the commercial power system 30 can be linked and operated through the power conversion device 70 described above.

  As shown in FIG. 3, an AC voltage P1 whose voltage change has been reduced through a reactor 73a of the smoothing circuit 73 is composed of a generated waveform W1 and a harmonic component W2. The generated waveform W1 is a waveform to be generated by the power conversion device 70, and is, for example, a waveform having a frequency of 50 Hz or 60 Hz of commercial power. The harmonic component W2 is a component generated in synchronization with the switching frequency.

In the case of the electrical circuit diagram shown in FIG. 3, the power conversion device 70 is connected between the fuel cell 1 and the commercial power grid 30, and no other electronic device is connected to the power conversion device 70. In this case, a circuit including the fuel cell 1 and the power converter 70 is one circuit. Therefore, due to the presence of the capacitor C1, most of the harmonic component W2 of the AC voltage P1, for example, approximately 100% of the harmonic component W2 proceeds toward the reactor 73b and returns to the inside of the power conversion device 70. That is, the AC voltage P1 including approximately 100% of the harmonic component W2 returns to the power converter 70, and the AC voltage P2 substantially not including the harmonic component W2 is the booster circuit 71, the inverter circuit 72, and the smoothing circuit. It is output to the outside from the closed circuit consisting of 73 and is output to the commercial power system 30.
The AC voltage P1 is a voltage that has passed through the reactor 73a and returns to the inside of the power conversion device 70 as described above, but the voltage that has passed through the reactor 73b also returns to the inside of the power conversion device 70 as described above.

  Next, an electric circuit in which an electronic device other than the fuel cell 1 is connected to the power conversion device 70 shown in FIG. 3 will be considered. Here, as other electronic devices, for example, home electric appliances such as an air conditioner 10c, a lighting 10d, a television 10e and a refrigerator 10f shown in FIG. 1 and other power generation devices such as a solar power generation device can be mentioned. FIG. 4 is an electric circuit diagram in which a solar power generation device as another electronic device is connected to the power conversion device connected between the fuel cell and the commercial power system.

  In FIG. 4, the configuration in which the power conversion device 70 is connected to the anode 15 and the cathode 16 of the fuel cell 1 is the same as that in FIG. 3. In the electric circuit diagram of FIG. 4, unlike FIG. 3, a solar power generation device 90 is connected to the power conversion device 70 as another electronic device. Further, the power conversion device 70 is connected to a power conversion device 80 that converts direct current voltage of direct current power generated by the solar power generation device 90 into alternating current voltage of commercial power of the commercial power system 30. The power conversion device 80 is connected to the solar power generation device 90, and includes a booster circuit 81, an inverter circuit 82, and a smoothing circuit 83. The inverter circuit 82 includes switching elements 82a to 82d and free wheeling diodes D8a to D8d. The smoothing circuit 83 includes a reactor 83a, a reactor 83b, and a capacitor C2. The booster circuit 81, the inverter circuit 82, and the smoothing circuit 83 have the same configuration as the booster circuit 71, the inverter circuit 72, and the smoothing circuit 73 of the power conversion device 70, and thus the description thereof will be omitted.

  As in FIG. 3, the booster circuit 71, the inverter circuit 72 and the smoothing circuit 73 constitute a closed circuit. Further, one end of the capacitor C1 and the output end of the reactor 73a are connected by a node N1, and the other end of the capacitor C1 and the output end of the reactor 73b are connected by a node N2. The booster circuit 71, the inverter circuit 72 and the smoothing circuit 73 are connected to the node N1 and the node N2 in the closed circuit, and the opposite side of the node N1 and the node N2 to the closed circuit is outside the closed circuit.

  Similar to FIG. 3, in FIG. 4 also, the DC voltage generated by the fuel cell 1 is converted into an AC voltage through the booster circuit 71 and the inverter circuit 72 and is input to the smoothing circuit 73. An AC voltage P1 passed through the reactor 73a is composed of a generated waveform W1 and a harmonic component W2. Here, in the electric circuit of FIG. 4, a solar power generation device 90 is connected to the power conversion device 70 as another electronic device, and the fuel cell 1, the power conversion device 70, the power conversion device 80 and the solar power generation device 90 The circuit including is one circuit. In this circuit, generally, the capacity of the capacitor C1 of the power conversion device 70 on the fuel cell 1 side is smaller than the capacity of the capacitor C2 of the power conversion device 80 on the solar power generation device 90 side which is another electronic device. By thus reducing the capacity of the capacitor C1 on the fuel cell 1 side, for example, the cost of the fuel cell system 20 can be reduced. This is the same as when other electronic devices such as home appliances other than the solar power generation device 90 are connected to the power conversion device 70. That is, the capacity of the capacitor C1 on the fuel cell 1 side is smaller than the capacity of the capacitor C2 on the other electronic device such as a home appliance.

  Thus, when the circuit including the fuel cell 1, the power conversion device 70, the power conversion device 80 and the solar power generation device 90 is configured in one circuit, the capacity of the capacitor C1 <the capacity of the capacitor C2 Therefore, the AC voltage is applied to the capacitor C2 more than the capacitor C1. Therefore, for example, 80% of the harmonic component W2 of the AC voltage P1 is output outside the closed circuit due to the presence of the capacitor C2, and the remaining 20% of the harmonic component W2 of the AC voltage P1 proceeds to the reactor 73b side. And return to the inside of the power converter 70. That is, the AC voltage including about 20% of the harmonic component W2 of the AC voltage P1 returns to the power conversion device 70, and the AC voltage P3 including about 80% of the harmonic component W2 of the AC voltage P1 is a boost circuit It is outputted to the outside from the closed circuit consisting of 71, the inverter circuit 72 and the smoothing circuit 73, and is outputted to the commercial power system 30.

  The AC voltage P3 is linked to the commercial power of the commercial power system 30, and is converted to an AC voltage P4 and applied to the capacitor C2 on the solar power generation apparatus 90 side. The AC voltage P4 includes the harmonic component W2 of the AC voltage P4 which is, for example, about 80% of the harmonic component W2 of the AC voltage P1. The AC voltage P4 is applied to the capacitor C2 to return to the power converter 70 on the fuel cell 1 side. Then, in the process of returning to the fuel cell 1 side, the AC voltage P4 is applied to the reactor 84 on the solar power generation device 90 side, which is another electronic device. Since the AC voltage P4 includes the harmonic component W2 of the AC voltage P4, which is, for example, about 80% of the harmonic component W2 of the AC voltage P1 as described above, The voltage is applied to the reactor 84. Therefore, reactor 84 is magnetostricted by harmonic component W2, that is, distortion occurs in the shape due to the influence of harmonic component W2 of AC voltage P4, and reactor 84 generates abnormal noise. Here, reactor 84 is affected by harmonic component W2 of AC voltage P4, but electronic components other than reactor 84 of other electronic devices are also affected by harmonic component W2 of AC voltage P4 and abnormal noise is generated. Can occur. As described above, if the reactor 84, which is an electronic component of another electronic device, generates abnormal noise, a noise problem occurs. In addition, when the other electronic component is a component related to lighting, this component is affected by the harmonic component W2 of the AC voltage P4 to cause problems such as flickering of the lighting.

(3-2) Configuration for Suppressing Problems of Noise, Lighting Flicker, etc. In the present embodiment, in order to suppress the problems of noise, lighting flicker, etc. described above, the power conversion device 70 uses switching elements 72a to 72d. Control switching frequency. Before control, the switching frequency is assumed to be a relatively low frequency such as an audible range.
FIG. 5 is an electric circuit diagram of the power conversion device according to the embodiment. Specifically, the power conversion device 70 according to the present embodiment determines the harmonic component to determine whether or not the AC voltage includes a harmonic component other than the booster circuit 71, the inverter circuit 72, the smoothing circuit 73, and the like. The circuit further includes a unit 101 and a frequency control unit 103 that controls the switching frequency of the inverter circuit 72.

  As shown in FIG. 5, the harmonic component determination unit 101 monitors the power waveform of the AC voltage P3 output from the closed circuit including the booster circuit 71, the inverter circuit 72, and the smoothing circuit 73. Then, the harmonic component determination unit 101 determines whether or not the power waveform of the AC voltage P3 includes the harmonic component W2 other than the generated waveform W1. Furthermore, when the harmonic component determination unit 101 detects the harmonic component W2, the harmonic component determination unit 101 determines whether the frequency of the detected harmonic component W2 is equal to or less than the harmonic component threshold Th (threshold). The harmonic component threshold Th is defined, for example, at the frequency of the boundary between the audible range and the out-of-the-range range. That is, the harmonic component determination unit 101 determines whether the harmonic component W2 is a frequency component within the audible range. Then, the harmonic component determination unit 101 outputs the determination result to the frequency control unit 103.

  More specifically, an example of the operation of the harmonic component determination unit 101 will be described. For example, the harmonic component determination unit 101 Fourier-transforms the power waveform of the AC voltage P3 to generate the generated waveform W1 and the other harmonic components W2. To separate. At this time, the generated waveform W1 is a waveform having a peak at 50 Hz or 60 Hz. The harmonic component W2 is composed of a combination of a plurality of harmonic components. Therefore, the harmonic component W2 has a plurality of peaks at a predetermined frequency, and the harmonic component determination unit 101 detects the largest or dominant harmonic component as the harmonic component W2. Note that, since the harmonic component W2 is generated in synchronization with the switching frequency, the harmonic components having substantially the same frequency as the switching frequency are dominant among the harmonic components composed of a plurality of combinations. Then, the harmonic component determination unit 101 compares the detected frequency of the harmonic component W2 with the harmonic component threshold Th.

As a result of the determination by the harmonic component determination unit 101, when the AC voltage P3 includes the harmonic component W2 less than or equal to the harmonic component threshold Th, the frequency control unit 103 determines the switching frequency of the switching elements 72a to 72d as the current. Control to increase the switching frequency by a predetermined value. The predetermined value is not particularly limited, and is, for example, 5 kHz, and the switching frequency after being increased by the predetermined value is, for example, 20 kHz, 25 kHz, 30 kHz, or the like.
By thus raising the switching frequency, the frequency of the harmonic component W2 generated in synchronization with the switching frequency also rises. The switching frequency after rising is such a frequency that abnormal noise generated by the other electronic component does not become noise when the harmonic component W2 affected by the switching frequency flows into the electronic component of the other electronic device. For example, the switching frequency after rising is a frequency close to outside the audible range, more preferably a frequency outside the audible range. The frequency outside the audible range is, for example, 20 kHz or more. Such adjustment of the switching frequency is also effective in suppressing the flickering of the illumination.

  As described above, when the AC voltage P3 output from the closed circuit of the power conversion device 70 includes the harmonic component W2, the switching frequency of the inverter circuit 72 is controlled to be increased by a predetermined value. Since the harmonic component W2 is generated in synchronization with the switching frequency of the inverter circuit 72, the frequency of the harmonic component W2 also rises by raising the switching frequency. As a result, the frequency of abnormal noise generated from another electronic device approaches the outside of the audible range or the outside of the audible range due to the influence of the harmonic component W2. Therefore, abnormal noise becomes hard to hear to the ear, and the noise problem can be suppressed. Further, as the frequency of the harmonic component W2 is increased, the flickering interval of the illumination is narrowed, and the flickering problem can also be suppressed.

  Further, the power conversion device 70 controls the switching frequency to suppress the generation of noise due to the abnormal noise of other electronic devices connected to the power conversion device 70, the flickering of illumination, and the like. Therefore, it is not necessary for the other electronic devices to be equipped with a device for suppressing the generation of noise due to abnormal noise, flickering of illumination, etc. Furthermore, the other electronic devices need to be controlled for noise suppression and flicker suppression, etc. There is no Therefore, even when a device for noise suppression, flicker suppression, and the like and another new electronic device not having control are connected to the power conversion device 70, the power conversion device 70 causes noise due to the new electronic device. It is possible to suppress the generation of noise and flickering of lighting. Thereby, the freedom degree which can connect a new electronic device to the power converter device 70 can be improved.

  Note that, as a result of the determination by the harmonic component determination unit 101, when the AC voltage P3 does not include the harmonic component W2, or the AC voltage P3 includes the harmonic component W2, but exceeds the harmonic component threshold Th. The frequency control unit 103 maintains the switching frequency at the current frequency.

  Even after the frequency control unit 103 controls to increase the switching frequency, the harmonic component determination unit 101 monitors the power waveform of the AC voltage P3 output to the outside of the closed circuit, and similarly to the above, AC voltage P3. It is determined whether or not the power waveform of H includes a harmonic component W2 other than the generated waveform W1. When the harmonic component determination unit 101 detects the harmonic component W2, the harmonic component determination unit 101 determines whether the frequency of the detected harmonic component W2 is equal to or less than a harmonic component threshold Th (threshold). As a result of the determination by the harmonic component determination unit 101, when the AC voltage P3 includes the harmonic component W2 less than or equal to the harmonic component threshold Th, the frequency control unit 103 again determines the switching frequency higher than the current switching frequency. Control to raise the value.

On the other hand, when the harmonic component determination unit 101 does not detect the harmonic component W2, or when the frequency control unit 103 determines that the frequency of the harmonic component W2 exceeds the harmonic component threshold Th, The frequency control unit 103 lowers the switching frequency by a predetermined value. In this case, the power conversion efficiency of the power conversion device 70 can be improved by lowering the switching frequency.
Note that the predetermined value for raising the switching frequency may be different from or the same as the predetermined value for decreasing the switching frequency. Also, the width of the predetermined value may be constant or different.

(4) Frequency Control Flow for Suppression of Noise, Flickering of Illumination, etc. Next, harmonic component determination unit 101 and frequency control unit 103 for suppression of noise, flicker of illumination, etc. The frequency control flow in power conversion device 70 will be described. FIG. 6 is an example of a flowchart showing a frequency control flow in the power conversion device according to the embodiment.

Step S1: The harmonic component determination unit 101 monitors the power waveform of the AC voltage P3 output from the power conversion device 70, that is, the closed circuit.
Step S2: The harmonic component determination unit 101 determines whether the power waveform of the AC voltage P3 includes the harmonic component W2. When harmonic component determination unit 101 detects harmonic component W2 (Yes in step S2), the process proceeds to step S3. On the other hand, when the harmonic component determination unit 101 does not detect the harmonic component W2 (No in step S2), monitoring of the AC voltage P3 is continued in step S1.
Step S3: The harmonic component determination unit 101 compares the frequency of the harmonic component W2 with the harmonic component threshold Th and determines that the frequency of the harmonic component W2 is less than or equal to the harmonic component threshold Th (Yes in Step S3) The process proceeds to step S4. On the other hand, if the harmonic component determination unit 101 determines that the frequency of the harmonic component W2 exceeds the harmonic component threshold Th (No in step S3), monitoring of the AC voltage P3 is continued in step S1.

Step S4: The frequency control unit 103 controls the switching frequency of the switching elements 72a to 72d to be higher than the current switching frequency by a predetermined value.
Step S5: The harmonic component determination unit 101 continues to monitor the power waveform of the AC voltage P3.
Step S6: The harmonic component determination unit 101 determines whether the power waveform of the AC voltage P3 includes the harmonic component W2. When harmonic component determination unit 101 detects harmonic component W2 (Yes in step S6), the process proceeds to step S7. On the other hand, when the harmonic component determination unit 101 does not detect the harmonic component W2 (No in step S6), the process proceeds to step S8.

Step S7: The harmonic component determination unit 101 compares the frequency of the harmonic component W2 with the harmonic component threshold Th and determines that the frequency of the harmonic component W2 is less than or equal to the harmonic component threshold Th (Yes in Step S7) The process proceeds to step S4, and the frequency control unit 103 further raises the switching frequency. On the other hand, when the frequency control unit 103 determines that the frequency of the harmonic component W2 is larger than the harmonic component threshold Th (No in step S7), the process proceeds to step S8.
Step S8: The frequency control unit 103 controls the switching frequency to be lower than the current switching frequency by a predetermined value, such as returning the switching frequency to the initial value. Even after the switching frequency is lowered, the harmonic component determination unit 101 continues to monitor the power waveform of the AC voltage P3 in step S1.

[Another embodiment]
(1) In the above embodiment, one harmonic component threshold Th is compared with the frequency of the harmonic component, and switching of the power conversion device 70 is performed when the frequency of the harmonic component becomes less than or equal to the harmonic component threshold Th. Raise the frequency. However, the switching frequency may be controlled based on not only one harmonic component threshold Th but also a plurality of harmonic component thresholds.
For example, the harmonic component threshold includes a first harmonic component threshold Th1 and a second harmonic component threshold Th2 larger than the first harmonic component threshold Th1. Further, a first set frequency H1 described later is larger than a second set frequency H2.

When the harmonic component determination unit 101 detects the harmonic component W2 in the power waveform of the AC voltage P3, the detected harmonic component W2 is larger than the first harmonic component threshold Th1 and less than the second harmonic component threshold Th2 The frequency control unit 103 sets the switching frequency to the second set frequency H2. When the detected harmonic component W2 is equal to or less than the first harmonic component threshold Th1, the frequency control unit 103 sets the switching frequency to the first set frequency H1.
By gradually raising the switching frequency from the second setting frequency H2 to the first setting frequency H1 as the frequency of the harmonic component W2 decreases, the switching frequency can be set stepwise to a frequency outside the audible range or a frequency outside the audible range. If the switching frequency can be adjusted stepwise in this way, control is performed so that the switching frequency does not become excessively high, and problems such as noise and lighting flicker due to the influence of harmonic components synchronized with the switching frequency are suppressed. At the same time, reduction in the power conversion efficiency of the power conversion device 70 can be suppressed.

(2) In the above embodiment, when the harmonic component determination unit 101 detects the harmonic component W2 at the AC voltage P3 and the frequency of the harmonic component W2 is equal to or less than the harmonic component threshold Th, the frequency control unit 103 Control to increase the switching frequency. However, when the harmonic component W2 equal to or lower than the harmonic component threshold Th is detected, notification may be given to the user such as a serviceman, and the switching frequency to be set may be received from the user.
FIG. 7 is an electric circuit diagram of a power conversion device capable of receiving a switching frequency from a user. The power conversion device 70 of FIG. 7 includes a notification unit 105 and a setting reception unit 107 in addition to the power conversion device 70 of FIG. 5. The other configuration of the power conversion device 70 is the same as that of the embodiment, and thus the description thereof is omitted.

The control of the switching frequency in the power converter of FIG. 7 will be described below.
If the harmonic component determination unit 101 detects the harmonic component W2 at the AC voltage P3 and determines that the frequency of the harmonic component W2 is less than or equal to the harmonic component threshold Th, the notification unit 105 increases the switching frequency. The user is informed to input the set frequency H higher than the current switching frequency. The setting reception unit 107 receives an input of the set frequency H from the user. At this time, setting accepting portion 107 accepts setting frequency H only when input setting frequency H is higher than the current switching frequency, and when the input setting frequency H is lower than the current switching frequency, the user is new to the user Prompts the user to input a set frequency H. The frequency control unit 103 changes the current switching frequency to the received set frequency H.

  Here, as a member through which the user inputs the set frequency H, although not limited to this, the knob adjustment member 75 may be mentioned. FIG. 8 is a schematic view of a power conversion device provided with a knob adjustment member. The knob adjustment member 75 is, for example, a rotary knob, and the user can input a desired set frequency in a range of, for example, 0 to 40 kHz by rotating the knob adjustment member 75.

  Further, even after changing the current switching frequency to a higher setting frequency H, the harmonic component determination unit 101 monitors the AC voltage P3. If the harmonic component determination unit 101 ceases to detect the harmonic component W2 at the AC voltage P3, or if it is determined that the frequency of the detected harmonic component W2 is greater than the harmonic component threshold Th, the notification unit 105 In order to lower the switching frequency, the user is informed to input a set frequency H lower than the current switching frequency. The setting reception unit 107 receives an input of the set frequency H from the user. At this time, setting accepting portion 107 accepts setting frequency H only when input setting frequency H is lower than the current switching frequency, and when the input setting frequency H is higher than the current switching frequency, the user is new to the user Prompts the user to input a set frequency H. The frequency control unit 103 changes the current switching frequency to the received set frequency H. In the above case, the power conversion efficiency of the power conversion device 70 can be improved by lowering the switching frequency.

  In the above case, the setting accepting unit 107 may accept an input of a plurality of setting frequencies H having different frequency magnitudes in stages from the user. For example, when the user receives notification from the notification unit 105, the user first inputs the first set frequency H1 to the setting reception unit 107. The first set frequency H1 is higher than the current switching frequency. Even if the switching frequency is set by the first set frequency H1, if the harmonic component determination unit 101 determines that the frequency of the harmonic component W2 is equal to or lower than the harmonic component threshold Th, the notification unit 105 further increases the second The user is informed to input the set frequency H2. Therefore, the user adjusts the switching frequency by inputting a second set frequency H2 larger than the first set frequency H1 to the setting accepting unit 107. As described above, if the switching frequency can be adjusted stepwise, control is performed so that the switching frequency does not become excessively high, and power conversion is performed while suppressing problems such as noise and lighting flicker due to the influence of the harmonic component W2. It can suppress that the power conversion efficiency of the apparatus 70 falls.

(3) In the above embodiment, when the harmonic component determination unit 101 detects the harmonic component W2 at the AC voltage P3 and the frequency of the harmonic component W2 is equal to or less than the harmonic component threshold Th, the frequency control unit 103 Control to increase the switching frequency.
However, the power conversion device 70 may not be provided with the harmonic component determination unit 101. For example, when another electronic device is connected to power conversion device 70 and the user detects abnormal noise from the other electronic device, frequency control section 103 changes the switching frequency to the set frequency accepted from the user. It is also good.

  (4) In the above embodiment, the switching frequency of the switching elements 72a to 72d is increased when the frequency of the harmonic component W2 included in the power waveform of the AC voltage P3 is equal to or less than the harmonic component threshold Th (threshold). Control. However, when the power waveform of AC voltage P3 includes harmonic component W2, frequency control section 103 performs control to immediately raise the switching frequency without comparing with harmonic component threshold Th (threshold). It is also good.

  (5) In the said embodiment, the fuel cell system 20 was mentioned as the example as an electric power generation system installed in each household 10. FIG. However, the power generation system is not limited to this, and may be, for example, a power generation system such as wind power or sunlight.

  (6) In the above embodiment, although the harmonic component determination unit 101 and the frequency control unit 103 are separate functional units, these are integrated functional units, and this functional unit is the harmonic component determination unit 101 and the frequency The processing of each of the control units 103 may be performed integrally.

(7) In the above embodiment, the power conversion device 70 includes the booster circuit 71. However, the power conversion device 70 may not include the boosting circuit 71.
Note that the configurations disclosed in the above-described embodiment (including the other embodiments, and the same hereinafter) can be applied in combination with the configurations disclosed in the other embodiments as long as no contradiction arises. The embodiment disclosed in the present specification is an exemplification, and the embodiment of the present invention is not limited thereto, and can be appropriately modified without departing from the object of the present invention.

1: Fuel cell 20: Fuel cell system 30: Commercial power system 70: Power converter 72: Inverter circuit 80: Power converter 101: Harmonic component determination unit 103: Frequency control unit 103a: Notification unit 103b: Setting reception unit 103c : Change unit 105: Storage unit W1: Generated waveform W2: Harmonic component

Claims (13)

An inverter circuit having a switching element for converting a DC voltage of DC power generated by the power generation apparatus into an AC voltage, and forming a closed circuit,
A frequency control unit that raises the switching frequency of the switching element by a predetermined value when a harmonic component is included in the power waveform of the AC voltage output from the closed circuit of the inverter circuit to the outside;
Power converter comprising: A harmonic component determination unit that determines whether a power component of the AC voltage output from the closed circuit of the inverter circuit includes a harmonic component;
When the harmonic component determination unit determines that the power waveform of the AC voltage output from the closed circuit of the inverter circuit includes a harmonic component, the frequency control unit determines the switching frequency The power converter according to claim 1, which is increased by a predetermined value.   3. The frequency control unit according to claim 1, wherein the frequency control unit raises the switching frequency when the frequency of the harmonic component included in the alternating voltage output from the closed circuit of the inverter circuit is lower than a threshold. Power converter.   The power conversion device according to any one of claims 1 to 3, wherein the frequency control unit raises the switching frequency to a frequency outside the audible range.   If the power waveform of the AC voltage output from the closed circuit of the inverter circuit is not included in the power waveform of the AC voltage after the switching frequency is increased, the frequency control unit may switch the switching frequency The power converter according to any one of claims 1 to 4, wherein the power converter is lowered by a predetermined value. A harmonic component determination unit that determines whether a power component of the AC voltage output from the closed circuit of the inverter circuit includes a harmonic component;
A notification unit configured to notify that the switching frequency is increased by a predetermined value when the power waveform of the AC voltage includes a harmonic component;
A setting reception unit that receives a setting of a setting frequency that can increase the switching frequency by a predetermined value after notification by the notification unit;
And further
The frequency control unit raises the switching frequency to the setting frequency accepted by the setting accepting unit when a harmonic component is included in the power waveform of the AC voltage output from the closed circuit of the inverter circuit to the outside. The power converter according to claim 1.   The power conversion device according to claim 6, wherein the setting reception unit is configured to be able to receive the setting of the setting frequency in stages. If the harmonic component determination unit determines that the harmonic component is not included in the power waveform of the AC voltage output from the closed circuit of the inverter circuit after the switching frequency is increased, the notification unit Informs that the switching frequency is lowered by a predetermined value,
The setting reception unit receives setting of a setting frequency that can lower the switching frequency by a predetermined value,
The power conversion device according to claim 6, wherein the frequency control unit lowers the switching frequency to the setting frequency received by the setting receiving unit. The case where the power waveform of the AC voltage output from the closed circuit of the inverter circuit includes a harmonic component is the case where the other electronic device is connected to the power conversion device, the other electronic device Is at least either of generating abnormal noise having a frequency in the audible range under the influence of the harmonic component and generating flicker of light,
A setting reception unit that receives a setting of a setting frequency that can raise the switching frequency by a predetermined value when a power waveform of the AC voltage output from the closed circuit of the inverter circuit to the outside includes a harmonic component When,
The power conversion device according to claim 1, wherein the frequency control unit raises the switching frequency to the setting frequency accepted by the setting accepting unit.   The power conversion device according to claim 9, wherein the setting reception unit is configured to be capable of receiving the setting of the setting frequency in stages. What is claimed is: 1. A power conversion method in a power conversion device including a switching device and an inverter circuit forming a closed circuit, the power conversion method comprising:
Converting the DC voltage of the DC power generated by the power generation apparatus into an AC voltage by switching the switching element;
Increasing the switching frequency of the switching element by a predetermined value if a harmonic component is included in the power waveform of the alternating voltage output from the closed circuit of the inverter circuit to the outside;
Power conversion method. Determining whether a power component of the AC voltage output from the closed circuit of the inverter circuit includes a harmonic component;
Notifying that the switching frequency is increased by a predetermined value when a harmonic component is included in the power waveform of the AC voltage;
Receiving, after notification, a setting of a set frequency capable of increasing the switching frequency by a predetermined value;
And further
The power conversion method according to claim 11, wherein in the step of raising the switching frequency of the switching element by a predetermined value, the switching frequency is raised to the set frequency. The case where the power waveform of the AC voltage output from the closed circuit of the inverter circuit includes a harmonic component is the case where the other electronic device is connected to the power conversion device, the other electronic device Is at least either of generating abnormal noise having an audible frequency and / or generating light flicker under the influence of the harmonic component.
If a harmonic component is included in the power waveform of the AC voltage output from the closed circuit of the inverter circuit, a step of receiving a setting frequency setting that can increase the switching frequency by a predetermined value is further provided. Equipped
The power conversion method according to claim 11, wherein in the step of raising the switching frequency of the switching element by a predetermined value, the switching frequency is raised to the set frequency.

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