JP2011145849A - Electric equipment - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide electric equipment which can easily use both AC power or DC power according to a power supplying means in an installed place. <P>SOLUTION: The electric equipment 100 includes an attachment plug 3 and an outlet 4, which are attached to a casing 1, a rectifier circuit 7 and a smoothing capacitor 8. Commercial AC voltage received through the attachment plug 3 is rectified by the rectifier circuit 7. The smoothing capacitor 8 smoothes the output voltage from the rectifier circuit 7. DC voltage received through the outlet 4 is supplied to the smoothing capacitor 8 through a diode 5 for backflow prevention. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an electric device that can use both AC power and DC power.

  In recent years, global warming countermeasures have been taken up as a global issue. Specifically, efforts are being made to reduce the amount of fossil fuel used to reduce carbon dioxide emissions, which is one of the causes of global warming.

  Against this backdrop, in household electrical appliances (also called household appliances) such as air conditioners, refrigerators, and lighting equipment used in general households, energy consumption is reduced while maintaining basic performance. That is, energy saving is required, and technological development for that purpose is currently underway.

  In home appliances, the use of natural energy such as solar cells is also being promoted. For example, Japanese Patent Laid-Open No. 5-11871 (Patent Document 1) discloses a composite input inverter device to which both commercial AC power and DC power generated by a solar cell are input. The inverter device shown in this document includes a DC load connected to a commercial AC system via a rectifier circuit, and a solar cell connected to the output terminal of the rectifier circuit via a DC-DC converter. . In this configuration, the input voltage of the DC-DC converter is constantly adjusted to the optimum operating voltage value corresponding to the maximum power of the solar cell, and the maximum power of the solar cell in order to suppress the generation of surplus power of the solar cell. Is set below the maximum power consumption of the DC load.

Japanese Patent Laid-Open No. 5-11871

  By the way, recent home appliances such as an air conditioner (air conditioner), a refrigerator, and a washing machine usually have an inverter. When connecting these home appliances to a commercial AC system, it is necessary to repeat power conversion, such as converting commercial AC to DC once, and then converting it to high-frequency AC using an inverter. Loss occurs. Therefore, it is useful from the viewpoint of energy saving to make it possible to use DC power such as a solar battery or a DC power distribution system in addition to commercial AC power by using the composite input inverter device described in the above-mentioned document.

  However, since solar cells and DC power distribution systems are in the process of spreading, the power that can be used differs depending on the residential environment. For this reason, the present situation is that it is necessary to remodel or replace the home appliance according to the power supply means at the installation location of the home appliance, which is inconvenient and economical.

  The present invention has been made in consideration of the above problems, and an object of the present invention is to provide an electrical device that can easily use either AC power or DC power depending on the power supply means at the installation site. It is to be.

  In summary, the present invention is an electrical device, and includes a first connection portion, a rectifier circuit, a smoothing capacitor, a load, and a second connection portion. The first connection portion is attached to the outer portion of the electric device and is provided to receive a commercial AC voltage from the outside. The rectifier circuit rectifies the commercial AC voltage received via the first connection portion. The smoothing capacitor receives the output voltage of the rectifier circuit. The load is driven by the voltage across the smoothing capacitor. The second connection portion is attached to the outer portion of the electrical device, and is provided to receive the first DC voltage from the outside and supply the first DC voltage to the smoothing capacitor.

  In a preferred embodiment, the electrical device is provided in a first DC voltage supply path between the second connection portion and the smoothing capacitor, and the electric charge accumulated in the smoothing capacitor is in the direction of the second connection portion. And a first backflow prevention unit that prevents backflow.

  Preferably, the first DC voltage is supplied from a solar cell. In this case, the optimum operating voltage corresponding to the maximum output power of the solar cell is substantially equal to the peak value of the commercial AC voltage.

  In another preferred embodiment, the electric device is provided in a first DC voltage supply path between the second connection portion and the first backflow prevention portion in addition to the configuration of the above-described embodiment. And a first converter for converting the first DC voltage into a DC voltage of a different magnitude.

  Preferably, the first DC voltage is supplied from a solar cell. In this case, the first converter controls the output voltage of the first converter so as not to exceed the reference voltage set to a value equal to or higher than the peak value of the commercial AC voltage, and the input of the first converter. The voltage is controlled so as to be an optimum operating voltage corresponding to the maximum output power of the solar cell.

  Alternatively, in the case where the first DC voltage is supplied from the solar cell, the first converter is preferably a reference in which the output voltage of the first converter is set to a value equal to or higher than the peak value of the commercial AC voltage. Control is performed so as not to exceed the voltage, and control is performed so that the input power of the first converter becomes maximum.

  Preferably, in the above embodiment, the electric device further includes a third connection portion and a second backflow prevention portion. The third connection portion is attached to the outer portion of the electric device, and is provided to receive the second DC voltage from the outside and supply the second DC voltage to the smoothing capacitor. The second backflow prevention unit is provided in the second DC voltage supply path between the third connection unit and the smoothing capacitor, and the charge accumulated in the smoothing capacitor flows back in the direction of the third connection unit. To prevent it. Here, the first DC voltage is supplied from the DC distribution system, and the magnitude of the first DC voltage is substantially equal to the peak value of the commercial AC voltage. The second DC voltage is supplied from the solar cell, and the optimum operating voltage corresponding to the maximum output power of the solar cell is substantially equal to the peak value of the commercial AC voltage.

  In another embodiment of the present invention, preferably, the electric device further includes a third connection unit, a second backflow prevention unit, and a second converter. The third connection portion is attached to the outer portion of the electric device, and is provided to receive the second DC voltage from the outside and supply the second DC voltage to the smoothing capacitor. The second backflow prevention unit is provided in the second DC voltage supply path between the third connection unit and the smoothing capacitor, and the charge accumulated in the smoothing capacitor flows back in the direction of the third connection unit. To prevent it. The second converter is provided in a second DC voltage supply path between the third connection unit and the second backflow prevention unit, and converts the second DC voltage into DC voltages of different magnitudes. . Here, the first DC voltage is supplied from the DC distribution system, and the magnitude of the first DC voltage is substantially equal to the peak value of the commercial AC voltage. The second DC voltage is supplied from the solar cell. The second converter controls the output voltage of the second converter so that it does not exceed the reference voltage set to a value equal to or higher than the peak value of the commercial AC voltage, and the input voltage of the second converter Control to achieve the optimum operating voltage corresponding to the maximum output power of the battery.

  Alternatively, in the case where the second DC voltage is supplied from the solar cell, the second converter is preferably a reference in which the output voltage of the second converter is set to a value equal to or higher than the peak value of the commercial AC voltage. Control is performed so as not to exceed the voltage, and control is performed so that the input power of the second converter is maximized.

  According to the present invention, since the first connection part for receiving the commercial AC voltage from the outside and the second connection part for receiving the DC voltage from the outside are provided in the outer part of the electric equipment, Either AC power or DC power can be easily used depending on the power supply means.

It is a perspective view which shows the external appearance of the front side of the refrigerator 100 by Embodiment 1 of this invention. It is a perspective view which shows the external appearance of the back side of the refrigerator 100 of FIG. It is a figure for demonstrating the usage example of the outlet socket 4 of FIG. 1, FIG. It is a figure for demonstrating the structure and usage example of the refrigerator 100 of FIG. 1, FIG. 2 (when connected to the commercial alternating current power supply 28). It is a figure for demonstrating the other usage example of the refrigerator 100 of FIG. 1, FIG. 2 (when connected to the power supply 23 of a DC distribution system). It is a figure for demonstrating the further another usage example of the refrigerator 100 of FIG. 1, FIG. 2 (when connected to the commercial alternating current power supply 28 and the solar cell 35). It is a figure for demonstrating the current-voltage characteristic of a solar cell. It is a figure for demonstrating operation | movement of the solar cell 35 when the voltage output from the commercial alternating current power supply 28 increases in FIG. FIG. 6 is a perspective view showing an appearance on the back side of a refrigerator 101 as a modification of the first embodiment. It is a figure for demonstrating the structure and usage example of the refrigerator 102 by Embodiment 2 of this invention (when connected to the commercial alternating current power supply 28). It is a figure for demonstrating the other usage example of the refrigerator 102 of FIG. 10 (when connected to the power supply 23 of a DC distribution system). It is a figure for demonstrating the structure and usage example of the refrigerator 103 by Embodiment 3 of this invention (when connected to the commercial alternating current power supply 28 and the solar cell 35). FIG. 13 is a circuit diagram showing an example of the configuration of the DC-DC converter 34 of FIG. 12. It is a functional block diagram of the DC-DC converter 34 of FIG. It is a figure which shows the input-output relationship of the microcomputer 54 of FIG. It is a figure which shows the input-output relationship of control circuit IC2 of FIG. It is a perspective view which shows the external appearance of the back side of the refrigerator 104 by Embodiment 4 of this invention. It is a figure for demonstrating the structure and usage example of the refrigerator 104 of FIG. 17 (when connected to the commercial alternating current power supply 28 and the solar cell 35). It is a figure for demonstrating the other usage example of the refrigerator 104 of FIG. 18 (when connected to the power supply 23 and the solar cell 35 of a DC distribution system). It is a figure for demonstrating the structure and usage example of the refrigerator 105 by Embodiment 5 of this invention (when connected to the commercial alternating current power supply 28 and the solar cell 35). It is a figure for demonstrating the other usage example of the refrigerator 105 of FIG. 5 (when connected to the power supply 23 and the solar cell 35 of a DC distribution system). It is a figure for demonstrating the structure and usage example of the refrigerator 106 by Embodiment 6 of this invention (when connected to the two solar cells 35 and 37).

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. The same or corresponding parts are denoted by the same reference numerals, and description thereof will not be repeated. Hereinafter, a refrigerator using an inverter will be described as an example, but the present invention can be similarly applied to other home appliances such as an air conditioner and a washing machine.

<Embodiment 1>
1 is a perspective view showing an external appearance of a front side of a refrigerator 100 according to Embodiment 1 of the present invention.

  FIG. 2 is a perspective view showing the appearance of the back side of the refrigerator 100 of FIG. The refrigerator 100 has an external appearance of a housing 1 (outer part), a plug 3 attached to the housing 1 via an AC cord 2, an outlet 4 attached to the housing 1, and an outlet 4. A protective cover 11. The plug 3 is used as a first connection for connecting to a commercial AC system, and the outlet 4 is used as a second connection for connecting to a DC power source such as a DC power distribution system or a solar battery. The protective cover 11 is provided in order to avoid electric shock or electric leakage due to contact with the outlet 4.

  FIG. 3 is a diagram for explaining an example of use of the outlet 4 of FIGS. 1 and 2. The outlet 4 is connected to an outlet 22 attached to a wall surface 21 of a building such as a house, and a DC cord 24 having plugs 25 and 26 attached to both ends. The outlet 22 is installed to receive a DC voltage from the power source 23 of the DC power distribution system.

  FIG. 4 is a diagram for explaining the configuration and usage example of the refrigerator 100 of FIGS. 1 and 2. FIG. 4 shows a case where outlet 3 of refrigerator 100 is connected to outlet 27 for commercial AC power supply 28 provided on the wall surface of the house. The refrigerator 100 includes a rectifier circuit 7, a smoothing capacitor 8, an inverter 9, a synchronous motor 10, and a backflow prevention unit 18 provided inside the housing 1. The synchronous motor 10 is a motor built in the compressor of the refrigerator 100.

  The rectifier circuit 7 converts the commercial AC voltage received from the commercial AC power supply 28 via the outlet 27 and the plug 3 into a DC voltage. Rectifier circuit 7 includes diodes D1 and D2 connected in series in the reverse bias direction between nodes ND3 and ND4, and diodes D3 and D4 connected in series in the reverse bias direction between nodes ND3 and ND4. A commercial AC voltage is input between the connection node ND1 of the diodes D1 and D2 and the connection node ND2 of the diodes D3 and D4.

  The smoothing capacitor 8 is connected between the output nodes ND3 and ND4, and smoothes the output voltage of the rectifier circuit 7. When the effective value of the voltage of the commercial AC power supply 28 is 100V, the voltage at both ends of the smoothing capacitor 8 is approximately equal to 141V (the peak value of the voltage output from the commercial AC power supply 28) that is twice the route.

  The backflow prevention unit 18 is provided to prevent the charge accumulated in the smoothing capacitor 8 from backflowing toward the outlet 4. In the case of FIG. 4, the diode 5 is connected between the high voltage side terminal 4P of the outlet 4 and the high voltage side node ND3 of the smoothing capacitor 8 so that the node ND3 side becomes a cathode as the backflow prevention unit 18. The Contrary to the case of FIG. 4, a diode may be provided between the low voltage side terminal 4N of the outlet 4 and the low voltage side node ND4 of the smoothing capacitor 8 so that the node ND4 side becomes an anode.

  The inverter 9 converts the DC voltage across the smoothing capacitor 8 into a high-frequency three-phase AC voltage and supplies it to the synchronous motor 10. That is, the voltage across the smoothing capacitor 8 drives the inverter 9 and the synchronous motor 10 as loads. Thus, when the commercial AC power supply 28 is used as a power supply source, the operation of the refrigerator 100 is the same as that of a conventional refrigerator.

  FIG. 5 is a diagram for explaining another example of use of the refrigerator 100 of FIGS. 1 and 2. FIG. 5 shows a case where the outlet 4 of the refrigerator 100 is connected to the power source 23 of the DC distribution system shown in FIG. The power supply 23 of the DC distribution system and the commercial AC power supply 28 of FIG. 4 are not used simultaneously. However, from the viewpoint of the withstand voltage of the components of the inverter 9, the DC voltage supplied from the power supply 23 of the DC distribution system is twice the root of the effective value of the voltage of the commercial AC power supply 28 (the peak of the voltage output from the commercial AC power supply 28). Value).

  In FIG. 5, the DC voltage supplied from the power supply 23 of the DC distribution system is supplied to the smoothing capacitor 8 through the backflow prevention unit 18. As in the case of the commercial AC power supply 28 of FIG. 4, the inverter 9 receives the voltage across the smoothing capacitor 8, converts it to a high-frequency three-phase AC voltage, and outputs it to the synchronous motor 10.

  Thus, by attaching the outlet 4 for the power supply 23 of the DC distribution system to the casing 1 of the refrigerator 100, the power supply source can be easily used for both the commercial AC system and the DC distribution system. Can do.

  FIG. 6 is a diagram for explaining still another usage example of the refrigerator 100 of FIGS. 1 and 2. In FIG. 6, the case where the refrigerator 100 is connected to both the commercial alternating current power supply 28 and the solar cell 35 is shown. First, the characteristics of the solar cell 35 will be described.

  FIG. 7 is a diagram for explaining the current-voltage characteristics of the solar cell. 6 and 7, the operating point of the solar cell changes between the operating point Po corresponding to the open circuit voltage Vo on the current-voltage curve and the operating point Ps corresponding to the short-circuit current Is. Maximum output power is obtained at Pm. The voltage at the maximum output power is referred to as the optimum operating voltage Vm, and the current is referred to as the optimum operating current Im. The maximum output power corresponds to the area (Vm × Im) of the hatched portion in FIG. In general, it is desirable to use a solar cell in the vicinity of an operating point where the maximum output power can be obtained.

  The solar cell 35 in FIG. 6 is selected so that the optimum operating voltage Vm is near the root twice the effective value of the voltage of the commercial AC power supply 28 (the peak value of the voltage output from the commercial AC power supply 28). In this case, when the output power of the solar cell 35 exceeds the power required by the inverter 9 and the synchronous motor 10 as the load, the output voltage on the current-voltage curve in FIG. 7 is set so as to match the power consumption of the load. The operating point shifts from the point Pm to the point Po, and the voltage supplied across the smoothing capacitor 8 is maintained at a value larger than the peak value of the commercial AC voltage by the power supplied from the solar cell 35. For this reason, the diodes D <b> 1 and D <b> 3 of the rectifier circuit 7 are turned off, so that commercial AC power is not supplied to the refrigerator 100. That is, the refrigerator 100 operates only with the output power of the solar cell 35.

  On the other hand, when the output power of the solar cell 35 is less than the power required by the load, the voltage of the smoothing capacitor 8 cannot be maintained above the peak value of the commercial AC voltage only by the output power of the solar cell 35. For this reason, the shortage is supplied from the commercial AC power supply 28 to the home appliance. In the early morning, evening, and night when sunlight is insufficient, the output voltage of the solar cell 35 does not reach the peak value of the voltage output from the commercial AC power supply 28. In this case, the solar cell 35 does not contribute to the power supply to the refrigerator 100, and the refrigerator 100 operates only with the power supplied from the commercial AC power supply 28.

  FIG. 8 is a diagram for explaining the operation of solar cell 35 when the voltage output from commercial AC power supply 28 in FIG. 6 increases. With reference to FIGS. 6 and 8, for example, a case where the effective value of the commercial AC voltage is increased from 100 V to 110 V will be described. In this case, the peak value of the commercial AC voltage increases from 141V to 155V. Accordingly, as shown in FIG. 8, the operating point of the solar cell 35 shifts from the operating point Pm corresponding to the voltage Vm (141V) to the operating point P1 corresponding to the voltage V1 (155V). That is, the solar cell 35 operates following the fluctuation of the commercial AC voltage. Therefore, when the output power of the solar cell 35 at the new operating point P1 exceeds the power required by the load, the refrigerator 100 operates exclusively by the power supplied from the solar cell 35. When the output power of the solar cell 35 at the new operating point P1 is insufficient for the power required by the load, the shortage is supplied from the commercial AC power supply 28.

  In this way, in the circuit configuration shown in FIG. 8, the power generated by the solar cell 35 is preferentially supplied to the smoothing capacitor 8, and the inverter 9 and the synchronous motor 10 are operated by this power. Since only the shortage of power is supplied from the commercial AC power supply 28, the amount of commercial AC power used can be reduced, and the user of the refrigerator 100 can reduce the electricity bill and contribute to the reduction of carbon dioxide emissions. can do.

  FIG. 9 is a perspective view showing an appearance of the back side of refrigerator 101 as a modification of the first embodiment. An insertion plug 32 is attached to the casing 1 of the refrigerator 101 of FIG. 9 via a DC cord 31 instead of the outlet 4 of FIG. The plug 32 is used as a second connection part for connecting to the power supply 23 or the solar battery 35 of the DC power distribution system.

<Embodiment 2>
FIG. 10 is a block diagram showing a configuration of the refrigerator 102 according to the second embodiment of the present invention. Furthermore, the usage example of the refrigerator 102 is shown by FIG. 10, FIG. FIG. 10 shows a case where the outlet 3 of the refrigerator 102 is connected to an outlet 27 for a commercial AC power supply 28 provided on the wall of the house, and FIG. 11 shows that the outlet 4 of the refrigerator 102 is connected to the power supply 23 of the DC distribution system. Indicates the case.

  With reference to FIGS. 10 and 11, the refrigerator 102 further includes a DC-DC converter 14 provided in a DC voltage supply path between the outlet 4 and the backflow prevention unit 18. And different. The output node ND5 on the high voltage side of the DC-DC converter 14 is connected to the anode of the diode 5. The output node ND6 on the low voltage side of the DC-DC converter 14 is connected to the node ND4 on the low voltage side of the smoothing capacitor 8. Since the other points in FIGS. 10 and 11 are common to the refrigerator 100 in FIG. 4, the same or corresponding parts are denoted by the same reference numerals and description thereof will not be repeated.

  As shown in FIG. 11, the DC-DC converter 14 converts the DC voltage output from the power supply 23 into a DC voltage of a different magnitude when the outlet 4 is connected to the power supply 23 of the DC distribution system. For example, assuming that the rated voltage of the DC distribution system is 400 V, the DC-DC converter 14 converts the DC voltage of 400 V to the root of the effective value of the commercial AC voltage (the peak value of the voltage output from the commercial AC power supply 28). Equal, for example 141V). Therefore, if the voltage conversion rate by the DC-DC converter 14 is adjusted according to the rated voltage of the DC distribution system, the refrigerator 102 can be connected to the DC distribution system of any rated voltage.

  On the other hand, as shown in FIG. 10, when refrigerator 102 is connected to commercial AC power supply 28 via outlet 27, it is similar to the case described in FIG. 4 of the first embodiment, and therefore description thereof will not be repeated.

<Embodiment 3>
FIG. 12 is a diagram for explaining a configuration and an example of use of the refrigerator 103 according to the third embodiment of the present invention. FIG. 12 shows a case where the refrigerator 103 is connected to both the commercial AC power supply 28 and the solar battery 35.

  The refrigerator 103 in FIG. 12 differs from the refrigerator 102 in FIGS. 10 and 11 in that a DC-DC converter 34 that operates differently from the DC-DC converter 14 in FIGS. 10 and 11 is provided. The DC-DC converter 34 in FIG. 12 controls the output voltage so as not to exceed the reference voltage, and the input voltage and the input current correspond to the maximum output power of the solar cell 35 and the optimum operation voltage and the optimum operation, respectively. It controls so that it may become electric current (it calls MPPT (Maximum Power Point Tracking) control). In this case, the reference voltage is set to a value larger than the peak voltage that is twice the root of the effective value of the commercial AC voltage. Hereinafter, the configuration of the DC-DC converter 34 will be described in more detail. Other points in FIG. 12 are the same as those in FIGS. 10 and 11, and therefore, the same or corresponding parts are denoted by the same reference numerals and description thereof will not be repeated.

FIG. 13 is a circuit diagram showing an example of the configuration of the DC-DC converter 34 of FIG.
In FIG. 13, the output node ND11 on the high voltage side of the solar cell 35 is also referred to as a power supply node VCC1, and the output node ND12 on the low voltage side is also referred to as a ground node GND1. Further, the output node ND7 on the high voltage side of the DC-DC converter 34 is also referred to as a power supply node VCC2. The voltage of power supply node VCC1 is, for example, 20V, and the voltage of power supply node VCC2 is, for example, 150V.

  In the case of FIG. 13, the DC-DC converter 34 is an insulating flyback converter. Instead of the flyback converter, other types of DC-DC converters such as a forward converter and a non-insulated step-up / down chopper can be used. As shown in FIG. 13, the DC-DC converter 34 includes a conversion circuit 65, a smoothing capacitor 45, control circuits IC <b> 1 and IC <b> 2, a microcomputer (MCU: Micro Computer Unit) 54, an operational amplifier 55, and a diode 56. And resistive elements 46 to 50 and a photocoupler 60.

  The conversion circuit 65 includes a transformer 41, an N-channel MOS (Metal-Oxide Semiconductor) transistor 42 (also referred to as an NMOS transistor 42), a diode 43, and a smoothing capacitor 44. The primary winding 41A of the transformer 41, the MOS transistor 42, and the resistance element 46 are connected in series between the nodes ND11 and ND12. The secondary winding 41B of the transformer 41 and the diode 43 are connected in series between the output nodes ND7 and ND8. Here, the diode 43 is connected in such a polarity that current does not flow through the secondary winding 41B of the transformer 41 when the MOS transistor 42 is on. Smoothing capacitor 44 smoothes the voltage between output nodes ND7 and ND8.

  The smoothing capacitor 45 is connected between the node ND11 and a connection node ND13 between the NMOS transistor 42 and the resistance element 46. The smoothing capacitor 45 smoothes the DC voltage output from the solar cell 35.

  The control circuit IC1 is an integrated circuit (IC: Integrated Circuit) (also referred to as PWM-IC) for controlling the switching of the MOS transistor 42 by a PWM (Pulse-Width Modulation) method. Control circuit IC1 includes a comparator 51, a triangular wave oscillator 52 that oscillates at a carrier frequency, and a resistance element 53.

  The inverting (−) input terminal of the comparator 51 is connected to the ground node GND 1 via the triangular wave oscillator 52. The non-inverting (+) input terminal of the comparator 51 is connected to the node ND16. Node ND16 is connected to power supply node VCC1 through resistance element 53. As will be described later, a feedback voltage output from the control circuit IC2 and the microcomputer 54 is applied to the node ND16. The output terminal of the comparator 51 is connected to the gate of the MOS transistor 42. With such a configuration of the control circuit IC1, the MOS transistor 42 is turned on while the voltage input to the non-inverting (+) input terminal exceeds the output voltage of the triangular wave oscillator 52.

  The control circuit IC2 is an integrated circuit for feeding back the voltage between the output nodes ND7 and ND8 to the control circuit IC1 so that the output voltage of the DC-DC converter 34 becomes constant (also referred to as a shunt regulator). The control circuit IC2 includes a differential amplifier 57, an NPN-type bipolar transistor 58, and a DC power supply 59.

  The non-inverting (+) input terminal of the differential amplifier 57 is connected to the connection node ND15 of the resistance elements 49 and 50 connected in series between the output nodes ND7 and ND8. The inverting (−) input terminal of the differential amplifier 57 is connected to the output node ND8 on the low voltage side via the DC power supply 59. The output terminal of the differential amplifier 57 is connected to the base of the bipolar transistor 58. Resistance element 61, light emitting diode 60A constituting photocoupler 60, and bipolar transistor 58 are connected in series between output nodes ND7 and ND8 in this order. An auxiliary winding, a diode for rectifying the output voltage of the auxiliary winding, and a smoothing capacitor are further provided on the secondary side of the transformer 41, and a high voltage side node and a low voltage side output node ND8 of the smoothing capacitor are provided. The resistor element 61, the light emitting diode 60A, and the bipolar transistor 58 may be connected between them.

  According to the configuration of the control circuit IC2 described above, when the voltage between the output nodes ND7 and ND8 increases, the voltage at the non-inverting (+) input terminal of the differential amplifier 57 increases, so the base voltage of the bipolar transistor 58 increases. To do. As a result, since the amount of current flowing through the bipolar transistor 58 through the light emitting diode 60A increases, the amount of current of the phototransistor 60B constituting the photocoupler 60 also increases. When the current amount of the phototransistor 60B increases, the voltage at the node ND16 decreases, so the duty ratio of the MOS transistor 42 decreases, thereby suppressing an increase in voltage between the output nodes ND7 and ND8. Conversely, when the voltage between the output nodes ND7 and ND8 decreases, the amount of current flowing through the phototransistor 60B decreases, so the voltage at the node ND16 increases. As a result, a decrease in voltage between the output nodes ND7 and ND8 is suppressed. The output voltage of the DC power supply 59 is set to such a magnitude that the voltage between the output nodes ND7 and ND8 becomes a predetermined set voltage value by the above feedback control. In this case, the set voltage value between the output nodes ND7 and ND8 is a value (for example, 150 V) slightly higher than the peak value of the voltage output from the commercial AC power supply 28.

  The microcomputer 54 is provided to feed back the voltage between the output nodes ND11 and ND12 of the solar cell 35 and the output current of the solar cell 35 to the control circuit IC1 so that the input power of the DC-DC converter 34 becomes maximum. . The microcomputer 54 has analog input terminals AD1 and AD2 and an analog output terminal DA1. The analog input terminals AD1 and AD2 are connected to an A / D (Analog-to-Digital) converter (not shown) built in the microcomputer 54, and the analog output terminal DA1 is connected to a D / A (D / A ( Digital-to-Analog) converter (not shown).

  In order to detect the output current of the solar cell 35 (input current Iin of the DC-DC converter 34), a voltage applied across the resistance element 46 is input to the analog input terminal AD1. In order to detect the output voltage of the solar cell 35 (the input voltage Vin of the DC-DC converter 34), the analog input terminal AD2 of the resistance elements 47 and 48 connected in series between the output nodes ND11 and ND12 of the solar cell 35 Connected to connection node ND14. The microcomputer 54 outputs a control signal from the analog output terminal DA1 for controlling the deviation between the output power Pin obtained by multiplying the detected output voltage and output current of the solar battery 35 and the predetermined maximum output power as small as possible. Output.

  The operational amplifier 55 is used as a voltage follower. The non-inverting (+) input terminal of the operational amplifier 55 is connected to the analog output terminal DA 1 of the microcomputer 54, and the output terminal is connected to the inverting (−) input terminal and to the cathode of the diode 56. The anode of the diode 56 is connected to the node ND16.

  According to the above configuration, the current-voltage characteristics of the solar cell 35 change due to, for example, the change in solar radiation intensity, and the optimum corresponding to the maximum output power than the current output voltage between the output nodes ND11 and ND12 of the solar cell 35. When the operating voltage becomes high, the microcomputer 54 decreases the voltage output from the analog output terminal DA1. As a result, since the voltage at the node ND16 decreases, the duty ratio of the MOS transistor 42 decreases, the voltage between the output nodes ND11 and ND12 of the solar cell 35 increases, and the deviation from the maximum output power of the solar cell is suppressed. The Conversely, when the optimum operating voltage corresponding to the maximum output power is lower than the current output voltage between the output nodes ND11 and ND12 of the solar battery 35, the microcomputer 54 outputs the voltage output from the analog output terminal DA1. Increase. As a result, since the voltage of the node ND16 increases, the voltage between the output nodes ND11 and ND12 of the solar cell 35 decreases, and deviation from the maximum output power of the solar cell is suppressed.

  FIG. 14 is a functional block diagram of the DC-DC converter 34 shown in FIG. In FIG. 14, an OR circuit 66 is a negative logic OR circuit (wired OR) realized by pulling up the node ND16 of FIG.

  FIG. 15 is a diagram showing the input / output relationship of the microcomputer 54 of FIG. As described with reference to FIG. 13, the microcomputer 54 monitors the input voltage Vin and the input current Iin of the DC-DC converter 34, and controls the feedback voltage for controlling the product Pin to have a predetermined maximum output power Pm. Vfb1 is generated and output to the OR circuit 66 of FIG.

  FIG. 16 is a diagram showing the input / output relationship of the control circuit IC2 of FIG. As described with reference to FIG. 13, the control circuit IC2 monitors the output voltage Vout of the DC-DC converter 34, and performs feedback so as to control the output voltage Vout so as not to exceed a predetermined reference voltage (150V in FIG. 16). A voltage Vfb2 is generated and output to the OR circuit 66 of FIG.

  Therefore, when the generated power of the solar cell 35 is larger than the power required by the load (during light load), the feedback voltage Vfb2 output from the control circuit IC2 to the OR circuit 66 decreases, and thus DC-DC The on-time of MOS transistor 42 is suppressed so that the output voltage of converter 34 does not exceed a set value (for example, 150 V). On the other hand, when the amount of sunshine is small (during heavy load), such as in the morning or in the cloudy weather, the power generated by the solar cell 35 is smaller than the power required by the loads 9 and 10. In this case, the on-time of the MOS transistor 42 is suppressed so that the input power of the DC-DC converter 34 maintains the maximum output power by decreasing the feedback voltage Vfb1 output from the microcomputer 54 to the OR circuit 66. Is done.

  With the above configuration, the power generated by the solar cell 35 is preferentially supplied to the smoothing capacitor 8, and the inverter 9 and the synchronous motor 10 are operated by this power. Since only the shortage of power is supplied from the commercial AC power supply 28, the amount of commercial AC power used can be reduced, and the user of the refrigerator 100 can reduce the electricity bill and contribute to the reduction of carbon dioxide emissions. can do. Further, the provision of the DC-DC converter 34 has an advantage that the optimum operating voltage of the solar cell 35 is not limited to the vicinity of the peak value of the commercial AC voltage.

  Note that, unlike the MPPT control described above, the DC-DC converter 34 may monitor only the input voltage and perform control so that the input voltage becomes an optimum operating voltage corresponding to the maximum output power of the solar cell.

<Embodiment 4>
FIG. 17 is a perspective view showing the appearance of the back side of refrigerator 104 according to the fourth embodiment of the present invention. The refrigerator 104 in FIG. 17 differs from the refrigerator 100 in FIG. 2 in that it further includes an outlet 15 (connection portion) for connecting to the solar cell and its protective cover 17.

  FIG. 18 is a block diagram showing a configuration of the refrigerator 104 of FIG. Furthermore, the usage example of the refrigerator 104 is shown by FIG. 18, FIG. 18 shows a case where the refrigerator 104 is connected to the commercial AC power supply 28 and the solar battery 35, and FIG. 19 shows a case where the refrigerator 104 is connected to the power supply 23 and the solar battery 35 of the DC power distribution system. The solar cell 35 is selected such that the optimum operating voltage corresponding to the maximum output power is approximately equal to the root twice the effective value of the commercial AC voltage (the peak value of the voltage output from the commercial AC power supply 28). The rated voltage of the DC distribution system is also set to be approximately equal to twice the root of the effective value of the commercial AC voltage (the peak value of the voltage output from the commercial AC power supply 28).

  18 and 19, refrigerator 104 is different from refrigerator 100 in FIG. 4 in that it further includes a backflow prevention unit 19 provided in a DC power path between outlet 15 and smoothing capacitor 8. The backflow prevention unit 19 is provided to prevent the charge accumulated in the smoothing capacitor 8 from backflowing toward the outlet 15. In the case of FIGS. 18 and 19, the backflow prevention unit 19 includes a diode 16 between the high voltage side terminal 15P of the outlet 15 and the high voltage side node ND3 of the smoothing capacitor 8 so that the node ND3 side becomes a cathode. Is provided. 18 and FIG. 19, a diode is provided between the low voltage side terminal 15N of the outlet 15 and the low voltage side node ND4 of the smoothing capacitor 8 so that the node ND4 side becomes an anode. Also good.

  In the usage example of FIG. 18, the plug 3 of the refrigerator 104 is connected to the outlet 27 for the commercial AC power supply 28, and the outlet 15 of the refrigerator 104 is connected to the solar battery 35. Since the operation in this case is the same as that in FIG. 6 of the first embodiment, description thereof will not be repeated.

  In the usage example of FIG. 19, the outlet 4 of the refrigerator 104 is connected to the power source 23 of the DC distribution system, and the outlet 15 is connected to the solar battery 35. In this case, the output voltage of the solar cell 35 operates according to the current-voltage curve shown in FIG. 7, and is basically the same as the operation in the case of the commercial AC power supply 28 shown in FIG.

  More specifically, when the output power of the solar cell 35 exceeds the power required by the inverter 9 and the synchronous motor 10 as a load, the current shown in FIG. 7 is set so that the output power matches the power consumption of the load. The operating point shifts from the point Pm to the point Po on the voltage curve. In this case, since the voltage across the smoothing capacitor 8 exceeds the rated voltage of the DC distribution system, the refrigerator 104 operates only with the output power of the solar battery 35.

  On the other hand, when the output power of the solar cell 35 is less than the power required by the load, the voltage of the smoothing capacitor 8 can be maintained at a value equal to the rated voltage of the DC distribution system only by the output power of the solar cell 35. Can not. For this reason, the shortage is supplied to the refrigerator 104 from the power supply 23 of the DC distribution system. The output voltage of the solar cell 35 does not reach the rated voltage of the power source 23 of the DC distribution system in the early morning, evening, or night when the sunlight is insufficient. In this case, the solar cell 35 does not contribute to the power supply to the refrigerator 100, and the refrigerator 100 operates only with the power supplied from the power supply 23 of the DC distribution system.

  Furthermore, when the voltage of the power supply 23 of the DC distribution system increases from Vm to V1 as shown in FIG. 8, the operating point of the solar cell 35 is changed from Pm to P1 as the voltage of the power supply 23 of the DC distribution system increases. Shift to. Therefore, when the output power of the solar cell 35 at the new operating point P1 exceeds the power required by the load, the refrigerator 100 operates exclusively by the power supplied from the solar cell 35. When the output power of the solar cell 35 at the new operating point P1 is insufficient for the power required by the load, the shortage is supplied from the power supply 23 of the DC distribution system.

  With the above configuration, the power generated by the solar cell 35 is preferentially supplied to the smoothing capacitor 8, and the inverter 9 and the synchronous motor 10 are operated by this power. Since only the insufficient power is supplied from the power supply 23 of the DC distribution system, the amount of power used from the DC distribution system can be reduced, and the user of the refrigerator 100 can reduce the electricity bill and emit carbon dioxide. Can contribute to the reduction.

<Embodiment 5>
FIG. 20 is a block diagram showing a configuration of the refrigerator 105 according to the fifth embodiment of the present invention. Furthermore, the usage example of the refrigerator 105 is shown by FIG. 20, FIG. 20 shows a case where the refrigerator 105 is connected to the commercial AC power supply 28 and the solar battery 35, and FIG. 21 shows a case where the refrigerator 105 is connected to the power supply 23 and the solar battery 35 of the DC distribution system.

  Referring to FIGS. 20 and 21, refrigerator 105 includes an outlet 15 for connection to solar cell 35, and a DC-DC converter 34 provided in a DC power supply path between outlet 15 and smoothing capacitor 8. 11 differs from the refrigerator 102 of FIG. 11 in that it further includes a backflow prevention unit 19. The appearance of the refrigerator 105 is the same as FIG. 17 of the fourth embodiment.

  Since the configuration of DC-DC converter 34 in FIGS. 20 and 21 is the same as that shown in FIGS. 12 and 13, description thereof will not be repeated. As the backflow prevention unit 19 in FIGS. 20 and 21, the node ND3 side becomes a cathode between the output node ND7 on the high voltage side of the DC-DC converter 34 and the node ND3 on the high voltage side of the smoothing capacitor 8. A diode 16 is provided. 20 and 21, the node ND4 side becomes an anode between the output node ND8 on the low voltage side of the DC-DC converter 34 and the node ND4 on the low voltage side of the smoothing capacitor 8. A diode may be provided.

  In the usage example of FIG. 20, the plug 3 of the refrigerator 105 is connected to the outlet 27 for the commercial AC power supply 28, and the outlet 15 of the refrigerator 105 is connected to the solar battery 35. Since the operation in this case is the same as that in FIG. 12 of the third embodiment, detailed description will not be repeated. By providing the DC-DC converter 34, there is an advantage that the optimum operating voltage of the solar cell 35 is not limited to the vicinity of the peak value of the commercial AC voltage.

  In the usage example of FIG. 21, the outlet 4 of the refrigerator 105 is connected to the power source 23 of the DC distribution system, and the outlet 15 is connected to the solar battery 35. In this case, the DC-DC converter 14 controls the output voltage to be equal to the peak value of the commercial AC voltage (equal to the root twice the effective value of the commercial AC voltage). The DC-DC converter 34 controls the output voltage so as not to exceed the reference voltage, and the input voltage and the input current become the optimum operation voltage and the optimum operation current corresponding to the maximum output power of the solar cell 35, respectively. (MPPT control). The reference voltage at this time is set to a value larger than the peak value of the commercial AC voltage.

  Therefore, in FIG. 21, when the output power of the solar cell 35 exceeds the power required by the inverter 9 and the synchronous motor 10 as loads, the voltage across the smoothing capacitor 8 exceeds the peak value of the commercial AC voltage. Therefore, the refrigerator 105 operates only with the output power of the DC-DC converter 34. On the other hand, when the output power of the solar cell 35 is less than the power required by the load, the voltage of the smoothing capacitor 8 cannot be maintained at a constant value only by the output power of the DC-DC converter 34. For this reason, the shortage is supplied from the power supply 23 of the DC distribution system to the refrigerator 105 via the DC-DC converter 14. In the early morning, evening, and night when sunlight is insufficient, the output voltage of the DC-DC converter 34 does not reach the peak value of the commercial AC voltage. In this case, the solar cell 35 does not contribute to the power supply to the refrigerator 100, and the refrigerator 100 operates only with the power supplied from the power source 23 of the DC distribution system via the DC-DC converter 14.

  With the above configuration, the power generated by the solar cell 35 is preferentially supplied to the smoothing capacitor 8 via the DC-DC converter 34, and the inverter 9 and the synchronous motor 10 are operated by this power. Since only the insufficient power is supplied from the power supply 23 of the DC distribution system to the smoothing capacitor 8 via the DC-DC converter 14, the amount of power consumed from the DC distribution system can be reduced, and the user of the refrigerator 100 can be reduced. Can reduce electricity costs and contribute to reducing carbon dioxide emissions. Furthermore, the provision of the DC-DC converter 14 has an advantage that the magnitude of the DC voltage supplied from the power supply 23 of the DC distribution system does not need to be equal to the peak value of the commercial AC voltage.

<Embodiment 6>
FIG. 22 is a diagram for explaining a configuration and an example of use of the refrigerator 106 according to the sixth embodiment of the present invention. FIG. 22 shows a case where two solar cells are connected.

  The refrigerator 106 in FIG. 22 is different from the refrigerator in FIG. 21 in that a DC-DC converter 36 is provided instead of the DC-DC converter 14. The configuration of the DC-DC converter 36 is the same as the DC-DC converter 34 shown in FIGS. Further, the outlet 106 of the refrigerator 106 is different from the case of FIG. 21 in that a solar cell 37 is connected instead of the power source 23 of the DC distribution system. The other points in FIG. 22 are the same as those in FIG. 21, and therefore the same or corresponding parts are denoted by the same reference numerals and description thereof will not be repeated.

  With the above configuration, the power generated by the two solar cells 35 and 37 is preferentially supplied to the smoothing capacitor 8, and the inverter 9 and the synchronous motor 10 are operated by this power. Since only the insufficient power is supplied from the commercial AC power supply 28 to the smoothing capacitor 8 via the rectifier circuit 7, the amount of commercial AC power used can be reduced, and the user of the refrigerator 100 can reduce the electricity bill. At the same time, it can contribute to the reduction of carbon dioxide emissions. Furthermore, in the refrigerator 106, only at least one of the two solar cells 35 and 37 can be connected, and even if neither of the solar cells 35 and 37 is connected, as long as the commercial AC power supply 28 is connected, It can be used like a conventional refrigerator. Therefore, the solar cells 35 and 37 can be added later in order or the number of the solar cells 35 and 37 to be connected can be changed depending on the use environment, so that the home appliance has high versatility.

  The embodiment disclosed this time must be considered as illustrative in all points and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

  DESCRIPTION OF SYMBOLS 1 Case (outer part), 3 Plug (1st connection part), 4 Outlet (2nd connection part), 5,16 Diode, 7 Rectifier circuit, 8 Smoothing capacitor, 9 Inverter, 10 Synchronous motor, 14 DC-DC converter, 15 outlet (third connection part), 18, 19 backflow prevention part, 23 DC power supply system, 28 commercial AC power supply, 32 plug (second connection part), 34, 36 DC-DC converter, 35,37 solar cell, 100-106 refrigerator.

Claims (9)

Electrical equipment,
A first connection part attached to the outer part of the electric device for receiving a commercial AC voltage from the outside;
A rectifier circuit for rectifying the commercial AC voltage received via the first connection;
A smoothing capacitor that receives the output voltage of the rectifier circuit;
A load driven by the voltage across the smoothing capacitor;
An electrical device, comprising: a second connection portion that is attached to an outer portion of the electrical device, receives a first DC voltage from the outside, and supplies the first DC voltage to the smoothing capacitor.   The electric device is provided in a supply path of the first DC voltage between the second connection portion and the smoothing capacitor, and the electric charge accumulated in the smoothing capacitor is directed in the direction of the second connection portion. The electrical device according to claim 1, further comprising a first backflow prevention unit that prevents backflow.   The electrical device is provided in a supply path of the first DC voltage between the second connection unit and the first backflow prevention unit, and the first DC voltage is changed to a DC voltage of a different magnitude. The electric device according to claim 2, further comprising a first converter for conversion.   The electrical apparatus according to claim 2, wherein the first DC voltage is supplied from a solar cell, and an optimum operating voltage corresponding to the maximum output power of the solar cell is substantially equal to a peak value of the commercial AC voltage. The first DC voltage is supplied from a solar cell;
The first converter controls the output voltage of the first converter so as not to exceed a reference voltage set to a value equal to or higher than the peak value of the commercial AC voltage. The electric device according to claim 3, wherein the input voltage is controlled to be an optimum operating voltage corresponding to the maximum output power of the solar cell. The first DC voltage is supplied from a solar cell;
The first converter controls the output voltage of the first converter so as not to exceed a reference voltage set to a value equal to or higher than the peak value of the commercial AC voltage. The electric device according to claim 3, wherein the electric power is controlled to be maximized. The electrical equipment is
A third connecting portion attached to the outer portion of the electrical device, receiving a second DC voltage from the outside, and supplying the second DC voltage to the smoothing capacitor;
Provided in the second DC voltage supply path between the third connection portion and the smoothing capacitor, and prevents the charge accumulated in the smoothing capacitor from flowing backward in the direction of the third connection portion. And a second backflow prevention unit that
The first DC voltage is supplied from a DC distribution system, and the magnitude of the first DC voltage is substantially equal to the peak value of the commercial AC voltage,
The electrical apparatus according to claim 2, wherein the second DC voltage is supplied from a solar cell, and an optimum operating voltage corresponding to the maximum output power of the solar cell is substantially equal to a peak value of the commercial AC voltage. The electrical equipment is
A third connecting portion attached to the outer portion of the electrical device, receiving a second DC voltage from the outside, and supplying the second DC voltage to the smoothing capacitor;
Provided in the second DC voltage supply path between the third connection portion and the smoothing capacitor, and prevents the charge accumulated in the smoothing capacitor from flowing backward in the direction of the third connection portion. A second backflow prevention unit that
A second DC voltage is provided in the second DC voltage supply path between the third connection unit and the second backflow prevention unit, and converts the second DC voltage into a DC voltage of a different magnitude. With a converter,
The first DC voltage is supplied from a DC distribution system, and the magnitude of the output voltage of the first converter is substantially equal to the peak value of the commercial AC voltage,
The second DC voltage is supplied from a solar cell;
The second converter controls the output voltage of the second converter so as not to exceed a reference voltage set to a value equal to or higher than the peak value of the commercial AC voltage. The electric device according to claim 3, wherein the input voltage is controlled to be an optimum operating voltage corresponding to the maximum output power of the solar cell. The electrical equipment is
A third connecting portion attached to the outer portion of the electrical device, receiving a second DC voltage from the outside, and supplying the second DC voltage to the smoothing capacitor;
Provided in the second DC voltage supply path between the third connection portion and the smoothing capacitor, and prevents the charge accumulated in the smoothing capacitor from flowing backward in the direction of the third connection portion. A second backflow prevention unit that
A second DC voltage is provided in the second DC voltage supply path between the third connection unit and the second backflow prevention unit, and converts the second DC voltage into a DC voltage of a different magnitude. With a converter,
The first DC voltage is supplied from a DC distribution system, and the magnitude of the output voltage of the first converter is substantially equal to the peak value of the commercial AC voltage,
The second DC voltage is supplied from a solar cell;
The second converter controls the output voltage of the second converter so as not to exceed a reference voltage set to a value equal to or higher than the peak value of the commercial AC voltage. The electric device according to claim 3, wherein the electric power is controlled to be maximized.

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