Power conversion device and control method for power conversion device

Abstract

To provide a power conversion device that can improve output by using battery power in combination with a commercial power source while satisfying the power constraints of a commercial power source.SOLUTION: A power conversion device includes a first circuit that receives a first power supply as input and outputs a desired DC voltage, a second circuit that receives a second power supply as input and has an output terminal connected to the output terminal of the first circuit, and a control circuit that controls the first circuit and the second circuit, and the control circuit has a first operating mode in which it controls the DC voltage to a first voltage by operating either the first circuit or the second circuit, and a second operating mode in which it controls the DC voltage to a second voltage higher than the first voltage by operating both the first circuit and the second circuit.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a configuration of a power conversion device and a control method thereof, and more particularly to a technique that is effective when applied to a household electrical appliance that is equipped with a battery and uses battery power in combination with a commercial power source. [Background technology]

[0002] With the spread of renewable energy sources such as solar power generation, whose output fluctuates due to weather conditions, there is an increasing need for demand response capabilities in home appliances to utilize surplus electricity.

[0003] In addition, battery systems for homes have been proposed as a backup in the event of a power outage caused by a disaster, but this poses issues in terms of user convenience, as it requires switching the breaker and changing the connection destination of home appliances during a power outage.

[0004] Furthermore, because AC power outlets in ordinary households have limited power capacity, it is difficult to increase the output of home appliances that run solely on commercial AC power. This poses a difficult challenge to achieving significant performance improvements in home appliances, such as increasing the cooking power of a home oven range or shortening the hot water wash time of a washing machine.

[0005] Background art in this technical field includes, for example, technology such as that disclosed in Patent Document 1. Patent Document 1 proposes a configuration capable of responding to peak shaving by connecting an AC / DC circuit and a battery in parallel between an AC power supply line and a load, and supplying battery power from the AC / DC circuit to the load via the AC power supply line, for the purpose of responding to demand response and providing backup during power outages, thereby limiting power from the AC power supply to a predetermined value or less. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Laid-Open No. 2003-309927 Summary of the Invention [Problem to be solved by the invention]

[0007] In the technology described in Patent Document 1, the power supplied from the battery to the load is controlled by an AC / DC circuit connected in parallel to the AC power supply.

[0008] In order to supply power exceeding the power constraints of the AC power supply to a resistive load such as a cooking heater in a domestic oven range or a hot water generating heater in a washing machine, it is necessary to increase the voltage applied to the heater. However, with the technology described in Patent Document 1, the voltage applied to the load is limited by the voltage of the AC power supply, making it difficult to supply power exceeding the power constraints of the AC power supply to a resistive load.

[0009] SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a power conversion device and a control method for a power conversion device that can improve output by using battery power in combination while satisfying the power constraints of a commercial power source. [Means for solving the problem]

[0010] In order to solve the above problem, the present invention comprises a first circuit that receives a first power supply as an input and outputs an arbitrary DC voltage, a second circuit that receives a second power supply as an input and has an output terminal connected to the output terminal of the first circuit, and a control circuit that controls the first circuit and the second circuit, wherein the control circuit has a first operating mode in which the DC voltage is controlled to a first voltage by operating either the first circuit or the second circuit, and a second operating mode in which the DC voltage is controlled to a second voltage higher than the first voltage by operating both the first circuit and the second circuit.

[0011] The present invention also provides a control method for a power conversion device that receives power from both a commercial AC power source and a battery, comprising: (a) converting an AC voltage supplied from the commercial AC power source into a DC voltage and controlling the DC voltage to a first voltage; and (b) combining the DC voltage supplied from the battery with the first voltage and controlling the second voltage to a second voltage higher than the first voltage. [Effects of the Invention]

[0012] According to the present invention, it is possible to realize a power conversion device and a control method for a power conversion device that can improve output by using battery power in combination while satisfying the power constraints of a commercial power source.

[0013] This will contribute to improving the performance of home appliances such as microwave ovens, washing machines, and refrigerators.

[0014] Problems, configurations, and effects other than those described above will become apparent from the following description of the embodiments. [Brief explanation of the drawings]

[0015] [Figure 1] 1 is a circuit diagram showing a schematic configuration of a power conversion device according to a first embodiment of the present invention and a microwave oven using the same. [Figure 2] 2 is a circuit diagram showing a configuration of an inverter 74 in FIG. 1. FIG. [Figure 3] FIG. 2 is a control block diagram of the control means 14 of FIG. [Figure 4] 2 is a flowchart showing a control method for the power conversion device 1 of FIG. [Figure 5] 2 is a diagram showing operation modes of the power conversion device 1 of FIG. 1 and a microwave oven 2 using the same. FIG. [Figure 6] 2 is a waveform diagram showing the operation of the power converter 1 of FIG. 1 and the microwave oven 2 using the same. FIG. [Figure 7] 2A and 2B are diagrams illustrating a modified example of the power conversion device 1 of FIG. 1 and its operation mode. [Figure 8]FIG. 10 is a circuit diagram showing a schematic configuration of a power conversion device according to a second embodiment of the present invention and a washer / dryer using the same. [Figure 9] 9 is a circuit diagram showing the configuration of inverters 174 and 175 in FIG. 8. [Figure 10] FIG. 9 is a control block diagram of the control means 114 of FIG. 8. [Figure 11] 9 is a diagram illustrating operation modes of the power conversion device 101 of FIG. 8 and the washer / dryer 100 using the same. [Figure 12] FIG. 10 is a circuit diagram showing a schematic configuration of a power conversion device according to a third embodiment of the present invention and a refrigerator using the same. [Figure 13] 13 is a diagram showing a power constraint command value of the power conversion device 201 of FIG. 12. FIG. [Figure 14] 13 is a diagram illustrating operation modes of a power converter 201 of FIG. 12 and a refrigerator 200 using the same. FIG. DETAILED DESCRIPTION OF THE INVENTION

[0016] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. In the drawings, the same components are designated by the same reference numerals, and detailed description of overlapping parts will be omitted. [Example]

[0017] <Configuration for microwave oven> 1 to 7, a configuration of a power conversion device and a control method thereof according to a first embodiment of the present invention will be described. In this embodiment, a configuration for a microwave oven will be described.

[0018] FIG. 1 is a circuit diagram showing the schematic configuration of a power conversion device 1 of this embodiment and an oven range 2 using the same. FIG. 2 is a circuit diagram showing the configuration of an inverter 74 of FIG. 1. FIG. 3 is a control block diagram of the control means 14 of FIG. 1. FIG. 4 is a flowchart showing a control method for the power conversion device 1 of FIG. 1. FIG. 5 is a diagram showing operation modes of the power conversion device 1 of FIG. 1 and an oven range 2 using the same. FIG. 6 is a waveform diagram showing the operation of the power conversion device 1 of FIG. 1 and an oven range 2 using the same. FIG. 7 is a diagram showing a modified example of the power conversion device 1 of FIG. 1 and its operation mode.

[0019] As shown in Fig. 1, the microwave oven 2 of this embodiment is connected to a commercial AC power supply 4 and operates on power supplied from the commercial AC power supply 4. The microwave oven 2 mainly comprises a power conversion device 1, a battery 5, a switching circuit 6, and a load circuit 7.

[0020] The load circuit 7 is made up of heaters 71 and 72, which are loads, a rectifier 73, an inverter 74, a magnetron 75, and relays Ry1 to Ry4. The relays Ry1 to Ry4 are arranged between the commercial AC power supply 4 and the heaters 71 and 72, the rectifier 73, the inverter 74, and the magnetron 75.

[0021] The power conversion device 1 receives inputs from a commercial AC power supply 4 and a battery 5, and generates an arbitrary DC voltage Vdc.

[0022] 2, the inverter 74 is composed of a filter reactor L1, a filter capacitor CF, a switching element Q1, a resonant capacitor C1, a transformer Tr, rectifiers D21 and D22, and smoothing capacitors C21 and C22, and applies a high voltage of several kV to the magnetron 75. The transformer Tr is composed of a transformer core N21, a primary winding N11, and a secondary winding N22.

[0023] The heaters 71 and 72 are heat sources used for oven cooking, and may be carbon heaters, ceramic heaters, or the like.

[0024] The power conversion device 1 is composed of an AC / DC circuit 12 that receives an input from a commercial AC power supply 4 and outputs a desired DC voltage, a DC / DC circuit 13 that receives an input from a battery 5 and outputs a desired DC voltage, and control means 14 that generates drive signals for the AC / DC circuit 12 and the DC / DC circuit 13. The output terminals of the DC / DC circuit 13 are connected in parallel to the output terminals OEa and OEb of the AC / DC circuit 12.

[0025] The AC / DC circuit 12 is composed of a diode bridge DB, a switching leg SL1 in which a switching element Q11 having an anti-parallel diode and a diode Di1 are connected in series, a switching leg SL2 in which a switching element Q12 having an anti-parallel diode and a diode Di2 are connected in series, a reactor DCL1, and a smoothing capacitor Cm1. The diode bridge DB has the same function as the rectifier 73.

[0026] The reactor DCL1 is connected between the switching element Q11 and the diode Di1 in the switching leg SL1, and between the switching element Q12 and the diode Di2 in the switching leg SL2.

[0027] The DC / DC circuit 13 is made up of a reactor DCL2, switching elements Q21 and Q22 each having an anti-parallel diode, and a smoothing capacitor Cm2.

[0028] Reactors DCL1 and DCL2 smooth current pulses and suppress harmful harmonics on the power lines in each of the AC / DC circuit 12 and the DC / DC circuit 13. Smoothing capacitors Cm1 and Cm2 stabilize the rectified DC voltage in each of the AC / DC circuit 12 and the DC / DC circuit 13 by charging the portion higher than the average value of the rectified DC voltage and discharging the portion lower than the average value.

[0029] The power conversion device 1 of this embodiment shows a configuration example in which the voltage Vbat of the battery 5 is lower than the DC voltage Vdc.

[0030] The switching circuit 6 is composed of multiple (four in this example) relays Ry11 to Ry14, and by appropriately turning on and off each relay, it switches the connection between the load (load circuit 7) that supplies power according to the cooking mode and the output terminal of the power conversion device 1. In the example of Fig. 1, the switching circuit 6 switches the connection between the output of the power conversion device 1 and the loads, heaters 71 and 72 and magnetron 75.

[0031] The control means 14 of the power conversion device 1 of this embodiment (FIG. 1) will be described with reference to Fig. 3 to Fig. 5. Note that the symbols S100 to S500 in Fig. 4 indicate the steps in the processing flow, and the symbols in Fig. 3 to Fig. 5 correspond to the symbols in Fig. 1.

[0032] As shown in Figure 3, the control means 14 receives external signals such as a mode selection command, power constraint command values ​​Pac_x, Pb_x, a power target value Pload, and a battery charge amount Pb from a higher-level control means or the like, and is composed of a power distribution calculation block that generates a power control command value Pac_ref for the AC / DC circuit 12, a power control command value Pb_ref ​​for the DC / DC circuit 13, and a charge / discharge mode command MODE-X, a PWM generation block 1 that generates a PWM signal to control the AC / DC circuit 12, and a PWM generation block 2 that generates a PWM signal to control the DC / DC circuit 13.

[0033] The PWM generation block 1 generates an input current command Iac_ref using the power control command value Pac_ref and the power supply voltage Vac of the AC / DC circuit 12, calculates the deviation from the detected value Iac, and generates a PWM signal using the duty generated by PI control.

[0034] The PWM generation block 2 generates a battery current command value Ib_ref ​​using the power control command value Pb_ref ​​of the DC / DC circuit 13 and the battery voltage detection value Vbat, calculates the deviation from the detection value Ibat, and generates a PWM signal using the duty generated by PI control. Since the direction of power in the DC / DC circuit 13 differs depending on the operating mode of charging or discharging the battery 5, the switching element to be driven is selected based on the charge / discharge mode command MODE-X.

[0035] Next, the power distribution calculation block of the control means 14 will be described in detail below with reference to FIG.

[0036] <Step S100> If the input mode command value is the commercial AC power supply 4+battery 5 drive mode (Y), the process proceeds to step S101. If not (N), the process proceeds to step S200.

[0037] <Step S101> The power constraint command values ​​Pac_x, Pb_x and the battery charge amount Pb of the commercial AC power supply 4 and the battery 5 input from the upper control means are input. However, if the values ​​are set in step S201 or step S301, the set values ​​are input.

[0038] <Step S102> Using the input value in step S101, a power control command value Pb_ref ​​to be output from the DC / DC circuit 13 is calculated. In step S102, if the battery charge amount Pb of the battery 5 is equal to or less than the power constraint command value Pb_x of the battery 5, the power control command value Pb_ref ​​is set to the battery charge amount Pb. Otherwise, the power control command value Pb_ref ​​is set to the power constraint command value Pb_x of the battery 5.

[0039] <Step S103> A determination is made as to whether the power target value Pload input from the higher-level control means needs to be established. If the sum of the power constraint command value Pac_x of the commercial AC power supply 4 and the power control command value Pb_ref ​​of the DC / DC circuit 13 is equal to or greater than the power target value Pload (Y), the process proceeds to step S104. If the sum of the power constraint command value Pac_x of the commercial AC power supply 4 and the power control command value Pb_ref ​​of the DC / DC circuit is less than the power target value Pload (N), the process proceeds to step S105.

[0040] <Step S104> The power target value Pload is set to the load power command value Pload_ref.

[0041] <Step S105> The sum of the power constraint command value Pac_x of the commercial AC power supply 4 and the power control command Pb_ref ​​of the DC / DC circuit 13 is set as the load power command value Pload_ref.

[0042] <Step S106> A power control command value Pac_ref for the AC / DC circuit 12 is calculated from the load power command value Pload_ref and the power control command value Pb_ref ​​for the DC / DC circuit 13 .

[0043] <Step S107> A charge / discharge mode command value MODE-X is generated using the power command value Pb_ref ​​of the DC / DC circuit 13. In step S107, for example, if the power control command value Pb_ref ​​is greater than 0, a charge / discharge mode command value Mode1 is generated, if the power control command value Pb_ref ​​is smaller than 0, a charge / discharge mode command value Mode2 is generated, and if the power control command value Pb_ref ​​is 0, a charge / discharge mode command value Mode3 is generated.

[0044] <Step S200> If the input mode command value is the battery-powered mode (Y), the process proceeds to step S201. If it is not (N), the process proceeds to step S300.

[0045] <Step S201> The power constraint command value Pac_x of the commercial AC power supply 4 and the power control command value Pac_ref of the AC / DC circuit 12 are set to zero, and the process proceeds to step S101.

[0046] <Step S300> If the input mode command value is the AC power supply drive mode (Y), the process proceeds to step S301. If not (N), the process proceeds to step S400.

[0047] <Step S301> The power constraint command value Pb_x of the battery 5 and the power control command value Pb_ref ​​of the DC / DC circuit 13 are set to zero, and the process proceeds to step S101.

[0048] <Step S400> If the input mode command value is the charge mode (Y), the process proceeds to step S401. If not (N), the process proceeds to step S500.

[0049] <Step S401> The power control command value Pac_ref of the AC / DC circuit 12 is set to the power constraint command value Pac_x of the AC power supply, and the power control command value Pb_ref ​​of the DC / DC circuit is set to a predetermined charging power value Pch, and the process proceeds to step S107.

[0050] <Step S500> The power control command value Pac_ref of the AC / DC circuit 12 and the power control command value Pb_ref ​​of the DC / DC circuit 13 are set to zero, and an error signal is set, and the process proceeds to step S107.

[0051] Next, details of each operation mode will be described below with reference to Figures 5 and 6. Note that the operation mode for supplying power to the load (load circuit 7) is shown for the heaters 71 and 72.

[0052] <Mode A: AC power supply> In this mode, power is supplied to the load only from the commercial AC power supply 4, and all of the switching elements Q11, Q12, Q21, and Q22 in the AC / DC circuit 12 and DC / DC circuit 13 are turned off. Furthermore, all of the relays Ry11 to Ry14 in the switching circuit 6 are also turned off. The relay Ry4 in the load circuit 7 is turned on, and the relays Ry1 to Ry3 are controlled to be on or off according to the load selected in accordance with the cooking sequence. For example, when power is supplied only to the heater 71, Ry1 is turned on.

[0053] <Mode B: Battery powered> In this mode, power is supplied to the load only from the battery 5, and all of the switching elements Q11 and Q12 in the AC / DC circuit 12 are in the OFF state. The switching element Q21 in the DC / DC circuit 13 performs a switching operation, and the switching element Q22 is in the OFF state. The relays Ry1 to Ry4 in the load circuit 7 are all in the OFF state, and the relays Ry11 to Ry14 in the switching circuit 6 are switched ON / OFF depending on the load to which power is being supplied. For example, when power is supplied to the heater 72, the relays Ry11 and Ry13 are turned ON.

[0054] <Mode C: AC power + battery powered> In this mode, the power of the commercial AC power supply 4 and the battery 5 is combined and supplied to the load, and switching elements Q11 and Q12 of AC / DC circuit 12 are switched. Switching element Q21 of DC / DC circuit 13 is switched, and switching element Q22 is turned off. Relays Ry1 to Ry4 of load circuit 7 are all turned off, and relays Ry11 to Ry14 of switching circuit 6 are switched on and off depending on the load to which power is being supplied.

[0055] For example, when power is supplied to the heater 71, the relays Ry11 and Ry14 are turned on, and when power is supplied to the heater 71 and the magnetron 75 simultaneously, the relays Ry11, Ry12, and Ry14 are turned on.

[0056] FIG. 6 shows the operating waveforms when power is supplied to the heater load in mode C.

[0057] At time t10, the DC voltage Vdc is controlled to the first voltage by starting the AC / DC circuit 12. At this time, the AC power supply power Pac=the load power Pload.

[0058] At time t11, the DC / DC circuit 13 is started up to combine the battery power Pbat and supply power to the load. At this time, the DC voltage Vdc is controlled to a second voltage higher than the first voltage.

[0059] By controlling the DC voltage Vdc in stages in this way, it is possible to supply power exceeding the power constraint of the commercial AC power supply 4 to the load while keeping the power of the commercial AC power supply 4 below the constraint.

[0060] In this embodiment, the AC / DC circuit 12 is started first, and then the DC / DC circuit 13 is started, but the DC / DC circuit 13 may be started first, and then the AC / DC circuit 12 may be started.

[0061] <Mode D: Charging mode> In this mode, the battery 5 is charged using power from the commercial AC power supply 4, and the DC voltage Vdc is controlled to a predetermined value by switching both switching elements Q11 and Q12 of the AC / DC circuit 12. The DC / DC circuit 13 receives the DC voltage Vdc as input, turns off switching element Q21, and switches switching element Q22 to supply a constant current to the battery 5. At this time, all relays in the switching circuit 6 and load circuit 7 are in the off state.

[0062] In this way, in the power conversion device 1 of this embodiment, the DC voltage in the first mode in which only either the first circuit or the second circuit is operated is controlled to a different value from the DC voltage in the second mode in which both the first circuit and the second circuit are operated.

[0063] This allows the power of the AC power supply and the battery power to be combined by varying the voltage applied to the resistive load while satisfying the power constraints of the commercial AC power supply 4, making it possible to supply power to the load that is greater than the power constraints of the commercial AC power supply 4.

[0064] Although the above describes an example of a configuration in which the battery 5 and DC / DC circuit 13 are connected in parallel to the AC / DC circuit 12 in the power conversion device 1, it is also possible to use a configuration in which the battery 5 and DC / DC circuit 13 are connected in series to the AC / DC circuit 12, as shown in a modified example in Fig. 7. The output terminals of the DC / DC circuit 13 are connected in series to the output terminals OEa and OEb of the AC / DC circuit 12.

[0065] In this case, as shown in the table of FIG. 7 , by controlling the on / off of relays Ry21 to Ry23 arranged between the AC / DC circuit 12 and the DC / DC circuit 13 according to the operation mode, the DC voltage in the first mode in which only the first circuit or the second circuit is operated and the DC voltage in the second mode in which both the first circuit and the second circuit are operated can be controlled to different values, just like in the case of a parallel connection. [Example]

[0066] <Configuration for washer-dryer> A configuration of a power conversion device and a control method thereof according to a second embodiment of the present invention will be described with reference to Fig. 8 to Fig. 11. In this embodiment, a configuration for a washer / dryer will be described. However, portions that overlap with the description of the first embodiment will be omitted.

[0067] Fig. 8 is a circuit diagram showing a schematic configuration of a power conversion device 101 of this embodiment and a washer / dryer 100 using the same. Fig. 9 is a circuit diagram showing the configuration of inverters 174, 175 of Fig. 8. Fig. 10 is a control block diagram of control means 114 of Fig. 8. Fig. 11 is a diagram showing operation modes of the power conversion device 101 of Fig. 8 and a washer / dryer 100 using the same.

[0068] 8, the washer-dryer 100 of this embodiment is connected to a commercial AC power supply 4 and operates on power supplied from the commercial AC power supply 4. The washer-dryer 100 mainly includes a power conversion device 101, a battery 5, inverters 174 and 175, motors 176 and 177, and a heater 172.

[0069] The power conversion device 101 receives AC power supplied from a commercial AC power supply 4 as an input and generates a DC voltage Vdc1.

[0070] As shown in FIG. 9, inverters 174 and 175 receive DC voltage Vdc1 as an input and are configured as three-leg inverters using six switching elements Qu1, Qu2, Qv1, Qv2, Qw1, and Qw2.

[0071] The inverter 174 and the motor 176 are devices for rotating the drum of the washer-dryer 100 , and the inverter 175 and the motor 177 are devices for driving a pump that circulates water within the washer-dryer 100 .

[0072] The heater 172 is a heat source for heating water during hot water washing, and may be, for example, a sheath heater.

[0073] The power conversion device 101 is composed of an AC / DC circuit 112 that receives AC power from a commercial AC power source 4 as input and generates a DC voltage, a DC / DC circuit 113 that receives DC power from a battery 5 as input and generates a DC voltage, and control means 114.

[0074] The AC / DC circuit 112 is composed of an AC reactor Lac, a rectifier 73, a smoothing capacitor Cdc, a switching leg SL1 in which a switching element Q11 equipped with an anti-parallel diode and a diode Di1 are connected in series, a reactor DCL1, and a smoothing capacitor Cm1.

[0075] The reactor DCL1 is connected between the switching element Q11 and the diode Di1 of the switching leg SL1, and is connected to the output terminal OEa of the AC / DC circuit 112 and one end of the smoothing capacitor Cm1.

[0076] The DC / DC circuit 113 is composed of a reactor DCL2, switching elements Q21 and Q22, and a smoothing capacitor Cm2.

[0077] When there is a voltage imbalance or the power supply impedance of commercial AC power supply 4 is small, AC reactor Lac suppresses the current flowing into AC / DC circuit 112 and protects AC / DC circuit 112.

[0078] Motors 176 and 177, which are loads, are connected between the terminals of smoothing capacitor Cdc via inverters 176 and 177, respectively, and switching leg SL1 is connected to the input terminal of a chopper circuit composed of reactor DCL1 and smoothing capacitor Cm1, and heater 172, which is a load, is connected to the output terminal of the chopper circuit.

[0079] As shown in Figure 10, like the control means 14 of Example 1, the control means 114 receives external signals such as a mode selection command, power constraint command values ​​Pac_x, Pb_x, a power target value Pload, and a battery charge amount Pb from a higher-level control means or the like, and is composed of a power distribution calculation block that generates a power command value Pac_ref for the AC / DC circuit 112, a power control command value Pb_ref ​​for the DC / DC circuit 113, and a charge / discharge mode command MODE-X, a PWM generation block 1 that generates a PWM signal to control the AC / DC circuit 112, and a PWM generation block 2 that generates a PWM signal to control the DC / DC circuit 113.

[0080] In this embodiment, the PWM generation block 1 calculates the deviation between a predetermined DC voltage command value Vdc_ref and the DC voltage detection value Vdc, and calculates a current amplitude command value Ia using PI control.The upper limit Ia_max of the current amplitude command value is calculated using the power control command value Pac_ref and the power supply voltage Vac of the AC / DC circuit 112, and if Ia>Ia_max by using a limiter, Ia=Ia_max.The deviation between the current command value Iacref and the detection value Iac is calculated, and a PWM signal is generated using the duty generated by PI control.

[0081] The PWM generation block 2 is the same as that in the first embodiment (FIG. 3), and therefore a description thereof will be omitted.

[0082] By using the control means 114 of this embodiment, it is possible to limit the DC voltage to a predetermined target value or less, so that it is possible to prevent element destruction due to overvoltage compared to the first embodiment.

[0083] The operation modes of the washer / dryer 100 of this embodiment will be described below with reference to FIG.

[0084] <Mode A: AC power supply> In this mode, power is supplied to the load only from the commercial AC power supply 4, and all of the switching elements Q11, Q21, and Q22 of the AC / DC circuit 112 and the DC / DC circuit 113 are turned off. The switching relays Ry21 and Ry22 are turned on when the heater 172 is driven, and turned off when the heater 172 is stopped.

[0085] <Mode B: Battery powered> This is a mode in which power is supplied to the load only from the battery 5, and the switching element Q11 of the AC / DC circuit 112 is turned off. The switching element Q21 of the DC / DC circuit 113 performs a switching operation, and the switching element Q22 is turned off.

[0086] When power is supplied only to the heater 172, the switching relay Ry21 is in the OFF state and Ry22 is in the ON state, and when power is supplied only to the inverters 174, 175, the switching relay Ry21 is in the ON state and Ry22 is in the OFF state.

[0087] <Mode C: AC power + battery powered> In this mode, the power of the commercial AC power supply 4 and the power of the battery 5 are combined and supplied to the load, and switching element Q11 of the AC / DC circuit 112 is caused to perform switching operation. Switching element Q21 of the DC / DC circuit 113 is caused to perform switching operation, and switching element Q22 is kept in the off state.

[0088] When power is supplied only to the heater 172, the switching relay Ry21 is in the OFF state and Ry22 is in the ON state, and when power is supplied only to the inverters 174, 175, the switching relay Ry21 is in the ON state and Ry22 is in the OFF state.

[0089] In mode C, first, the AC / DC circuit 112 is started and the DC voltage Vdc1 is controlled to a first voltage, and then the DC / DC circuit 113 is started to synthesize the DC voltage Vdc2 and control it to a second voltage higher than the first voltage.

[0090] By controlling the DC voltage in a stepwise manner in this manner, it is possible to supply power exceeding the power constraint of the commercial AC power supply 4 to the load while keeping the power of the commercial AC power supply 4 below the constraint, as in the first embodiment.

[0091] <Mode D: Charging mode> In this mode, the battery 5 is charged using power from the commercial AC power supply 4, and the DC voltage Vdc2 is controlled to a predetermined value by switching the switching element Q11 of the AC / DC circuit 112. The DC / DC circuit 113 receives the DC voltage Vdc2 as an input, turns off the switching element Q21, and switches the switching element Q22, thereby supplying a constant current to the battery 5. At this time, all switching relays Ry21 and Ry22 are in the off state.

[0092] In this way, in the power conversion device 101 of this embodiment, compared to the first embodiment, the rectifier 73 is configured to be shared with the inverter load, and thus costs can be expected to be reduced by reducing the number of additional parts. [Example]

[0093] <Configuration for refrigerators> A configuration of a power conversion device and a control method thereof according to a third embodiment of the present invention will be described with reference to Fig. 12 to Fig. 14. In this embodiment, a configuration for a refrigerator will be described. However, portions that overlap with the description of the first embodiment will not be described.

[0094] Fig. 12 is a circuit diagram showing a schematic configuration of a power conversion device 201 of this embodiment and a refrigerator 200 using the same. Fig. 13 is a diagram showing a power constraint command value of the power conversion device 201 of Fig. 12, and shows a time change in the power constraint of the AC power supply input to the power conversion device 201. Fig. 14 is a diagram showing operation modes of the power conversion device 201 of Fig. 12 and a refrigerator 200 using the same.

[0095] 12, a refrigerator 200 of this embodiment is connected to a commercial AC power supply 4 and operates using power supplied from the commercial AC power supply 4. The refrigerator 200 includes, as its main components, a power conversion device 201, a battery 5, an inverter 274, a motor 276, and a heater 272.

[0096] The power conversion device 201 receives AC power supplied from a commercial AC power supply 4 as an input and generates a DC voltage Vdc1.

[0097] The power conversion device 201 is composed of an AC / DC circuit 212 that receives AC power from a commercial AC power source 4 as input and generates a DC voltage, a DC / DC circuit 213 that receives DC power from a battery 5 as input and generates a DC voltage, and control means 214.

[0098] The inverter 274 and the motor 276 are devices that control the cooling compressor of the refrigerator 200.

[0099] The heater 272 is a heat source used for defrosting the inside of the refrigerator 200, and a ceramic heater or the like is used.

[0100] The AC / DC circuit 212 is a bidirectional chopper circuit made up of switching elements Q11 and Q12, a reactor DCL1, and a smoothing capacitor Cm1.

[0101] A motor 276 as a load is connected between the terminals of the smoothing capacitor Cdc via an inverter 274, and a heater 272 as a load is connected to the output end of a bidirectional chopper circuit formed by switching elements Q11 and Q12, a reactor DCL1, and a smoothing capacitor Cm1.

[0102] The DC / DC circuit 213 is a bidirectional H-bridge circuit made up of switching elements Q21, Q22, Q23, and Q24, a reactor DCL2, and a smoothing capacitor Cm2.

[0103] By configuring the DC / DC circuit 213 in this way, the battery 5 can be charged and discharged even when the battery voltage Vbat and the DC voltage Vdc2 have an arbitrary relationship.

[0104] The control means 215 receives a demand response command provided by an electric power company or the like, generates a power constraint command value for the commercial AC power supply 4 that changes at predetermined time intervals as shown in FIG. 13 based on the demand response command, and inputs the generated power constraint command value to the control means 214.

[0105] With this configuration, even when power constraints exceeding the power capacity limit of an average household are required, it becomes possible to control the power supplied from the commercial AC power supply 4 to any value for each individual home appliance.

[0106] Next, the operation modes of the power converter 201 and the refrigerator 200 using the same will be described with reference to FIG.

[0107] <Mode A: AC power supply> This is a mode in which power is supplied to the load only from the commercial AC power supply 4, and when power is supplied to the heater 272, the switching element Q11 of the AC / DC circuit 212 is turned on and the switching element Q12 is turned off. The switching elements Q21 to Q24 of the DC / DC circuit 213 are all turned off. The switching relay Ry22 is turned on when the heater 272 is driven, and is turned off when the heater 272 is stopped.

[0108] <Mode B: Battery powered> In this mode, power is supplied to the load only from the battery 5, and the switching element Q11 of the AC / DC circuit 212 is in the OFF state. The switching element Q12 is in the OFF state when power is supplied only to the heater 272, and performs a switching operation when power is supplied to the motor 276, thereby controlling the DC voltage Vdc1 to a constant value.

[0109] The switching elements Q21 and Q24 of the DC / DC circuit 213 are turned off, and the switching elements Q22 and Q23 are turned on or perform switching operation depending on the relationship between the battery voltage Vbat and the DC voltage Vdc2. When power is supplied to the heater 272, the switching relay Ry22 is turned on, and when power is supplied only to the inverter 274, the switching relay Ry22 is turned off.

[0110] <Mode C: AC power + battery powered> This is a mode in which the power of the commercial AC power supply 4 and the power of the battery 5 are combined and supplied to the heater load, in which the switching element Q11 of the AC / DC circuit 212 performs a switching operation and the switching element Q12 is in an OFF state.

[0111] The switching elements Q21 and Q24 of the DC / DC circuit 213 are turned off, and the switching elements Q22 and Q23 are turned on or perform switching operation depending on the relationship between the battery voltage Vbat and the DC voltage Vdc2. The switching relay Ry22 is turned on.

[0112] At this time, first, the AC / DC circuit 212 is started and the DC voltage Vdc1 is controlled to a first voltage, and then the DC / DC circuit 213 is started to synthesize the DC voltage Vdc2 and control it to a second voltage higher than the first voltage.

[0113] By controlling the DC voltage in a stepwise manner in this manner, it is possible to supply power exceeding the power constraint of the commercial AC power supply 4 to the load while keeping the power of the commercial AC power supply 4 below the constraint, as in the first embodiment.

[0114] <Mode D: Charging mode> In this mode, the battery 5 is charged using power from the commercial AC power supply 4, and the DC voltage Vdc2 is controlled to a predetermined value by switching the switching element Q11 of the AC / DC circuit 212. The DC / DC circuit 213 receives the DC voltage Vdc2 as an input, and the switching elements Q22 and Q23 are in the OFF state, while the switching elements Q21 and Q24 are in the ON state or perform switching operation depending on the relationship between the battery voltage Vbat and the DC voltage Vdc2, thereby supplying a constant current to the battery 5. At this time, the switching relay Ry22 is in the OFF state.

[0115] In this way, the power conversion device 201 of this embodiment is capable of distributing power in accordance with a demand response command while taking into account the power constraints of the commercial AC power source 4, and therefore, it is expected to be effective in reducing electricity charges by responding to demand response and peak shifting.

[0116] The present invention is not limited to the above-described embodiments and includes various modifications. For example, the above-described embodiments have been described in detail to clearly explain the present invention, and the present invention is not necessarily limited to those including all of the described configurations. Furthermore, it is possible to replace part of the configuration of one embodiment with the configuration of another embodiment, or to add the configuration of another embodiment to the configuration of one embodiment. Furthermore, it is possible to add, delete, or replace part of the configuration of each embodiment with other configurations. [Explanation of symbols]

[0117] 1,101,201...Power conversion device 2. Microwave oven 4…Commercial AC power supply 5. Battery 6...Switching circuit 7...Load circuit 12,112,212…AC / DC circuit 13,113,213…DC / DC circuit 14,114,214,215...Control means 71, 72, 172, 276...Heater 73... Rectifier 74, 174, 175, 274... Inverter 75...Magnetron 100...Washer / dryer 176, 177, 276...Motor 200...refrigerator C1: Resonant capacitor C21, C22...Smoothing capacitors CF: Filter capacitor Cm1, Cm2, Cdc...smoothing capacitors D21, D22: Rectifier diodes DB: Diode bridge DCL1, DCL2...Reactor Di1, Di2...Diodes L1...Filter reactor Lac...AC reactor N11: Primary winding N21...Transformer core N22: Secondary winding OEa, OEb...Output terminal Q1, Q11, Q12, Q21, Q22, Q23, Q24, Qu1, Qu2, Qv1, Qv2, Qw1, Qw2...switching elements Ry1~Ry4, Ry11~Ry14, Ry21~Ry23...Relay SL1, SL2...Switching legs Tr...transformer.

Claims

1. a first circuit that receives a first power supply as an input and outputs a DC voltage; a second circuit having an input connected to a second power supply and an output connected to the output of the first circuit; a control circuit that controls the first circuit and the second circuit; a first operation mode in which the control circuit controls the DC voltage to a first voltage by operating either the first circuit or the second circuit; A power conversion device having a second operation mode in which the DC voltage is controlled to a second voltage higher than the first voltage by operating both the first circuit and the second circuit.

2. The power conversion device according to claim 1, The power conversion device according to claim 1, wherein an output terminal of the second circuit is connected in parallel with an output terminal of the first circuit.

3. The power conversion device according to claim 1, The power conversion device according to claim 1, wherein the output terminal of the second circuit is connected in series with the output terminal of the first circuit.

4. The power conversion device according to claim 1, the control circuit inputs a power constraint command value of the first power supply, a power constraint command value of the second power supply, and a target power command value to be supplied to a load connected to an output terminal of the first circuit, and includes a power distribution calculation unit that calculates a first power control command value to be output by the first circuit and a second power control command value to be output by the second circuit.

5. The power conversion device according to claim 4, The load comprises a plurality of resistive loads; a plurality of changeover switches that switch connections between the output terminal of the first circuit and the plurality of resistive loads, A power conversion device characterized in that the number of resistive loads connected to the output terminal of the first circuit is changed by controlling the on or off of the changeover switch based on an operation mode command input to the control circuit.

6. The power conversion device according to claim 1, the first power source is a commercial AC power source, The power conversion device according to claim 1, wherein the second power source is a battery.

7. The power conversion device according to claim 4, The power conversion device according to claim 1, wherein the power constraint command value of the first power supply changes at predetermined time intervals.

8. The power conversion device according to claim 1, The first circuit includes a diode bridge and a first switching leg in which a first switching element and a first diode are connected in series; a second switching leg in which a second diode and a second switching element are connected in series; a reactor connected between a midpoint of the first switching leg and a midpoint of the second switching leg.

9. The power conversion device according to claim 1, The first circuit includes a first reactor; A rectifier; a first smoothing capacitor; a switching leg in which a switching element and a diode are connected in series; a second reactor; and a second smoothing capacitor; a first load is connected between terminals of the first smoothing capacitor, and an input end of a chopper circuit constituted by the switching leg, the second reactor, and the second smoothing capacitor is connected between terminals of the first smoothing capacitor; A power conversion device, characterized in that a second load is connected to the output terminal of the chopper circuit.

10. The power conversion device according to any one of claims 1 to 9, A power conversion device that is mounted on any one of an oven range, a washer / dryer, and a refrigerator.

11. A control method for a power conversion device to which power is supplied from both a commercial AC power supply and a battery, comprising: (a) converting an AC voltage supplied from the commercial AC power supply into a DC voltage and controlling the DC voltage to a first voltage; (b) combining the DC voltage supplied from the battery with the first voltage and controlling the second voltage to be higher than the first voltage; A control method for a power conversion device, comprising:

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