Energy Supply Device

Abstract

To provide an energy supply device which detects a type, a position and a size of a metal object placed on a top plate in the energy supply device capable of supplying energy to an object without contact.SOLUTION: An energy supply device for supplying energy to an object placed on a top plate without contact is arranged below the top plate and supplies energy to the object. The energy supply device includes: a plurality of coils 2 connected to an energy supply resonance capacitor 3 and an inverter circuit 4; a transmission circuit 61 for transmitting a detection signal of a prescribed frequency to one of the plurality of coils; a reception circuit 62 for detecting voltage or current inducted by any other coil different from the coil in accordance with the transmitted detection signal; and a switching control part 52 for selecting a transmission coil being a coil for transmitting the detection signal and a reception coil being a coil for detecting voltage or current from the plurality of coils to be sequentially switched.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to an energy supply device that can supply energy to an object without contact. [Background technology]

[0002] Conventionally, energy supply devices, such as induction heating devices and wireless power supply devices, have been known that utilize induced currents generated by high-frequency magnetic fields to supply energy such as heat or power to an object in a non-contact manner. Patent Document 1, for example, discloses an example of such an energy supply device: a wireless power transmission system equipped with a foreign object detection function that detects foreign objects, such as metal pieces, present near a wireless power transmission unit. This wireless power transmission system is configured to input the same detection signal to two adjacent coils and detect the change in impedance that occurs when a metal foreign object is present in either of the coils, thereby detecting the presence or absence of the foreign object. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2016-220523 Summary of the Invention [Problem to be solved by the invention]

[0004] However, the device disclosed in Patent Document 1 mentioned above only determines the presence or absence of a metallic foreign object by inputting a signal into two coils and detecting a change in impedance, and is not applicable to detecting the type, position, and size of a metallic object placed on the coils.

[0005] The present invention has been made to solve the above-mentioned problems, and its main objective is to detect the type, position, and size of a metal object placed on a top plate in an energy supply device that can supply energy to an object without contact. [Means for solving the problem]

[0006] In other words, the energy supply device of the present invention is an energy supply device that supplies energy non-contact to an object placed on a top plate, and is arranged under the top plate to supply energy to the object, and is characterized by comprising a plurality of coils connected to an energy supply resonant capacitor and an inverter circuit, a transmitting circuit that transmits a detection signal of a predetermined frequency to one of the plurality of coils, a receiving circuit that detects a voltage or current induced in any other coil different from the coil in accordance with the transmitted detection signal, and a switching control unit that selects and sequentially switches between a transmitting coil that transmits the detection signal and a receiving coil that detects the voltage or current from the plurality of coils.

[0007] With this configuration, the transmitter coil that transmits the detection signal via the transmitter circuit and the receiver coil that detects the voltage or current via the receiver circuit are selected from the multiple coils and switched sequentially, so the multiple coils arranged under the top plate can be used as both transmitter coils and receiver coils. Therefore, by setting the multiple coils arranged under the top plate in various combinations as transmitter coils and receiver coils and detecting the voltage or current from each receiver coil in response to the detection signal, it is possible to detect the type, position, and size of an object placed on the top plate.

[0008] As a specific aspect of the energy supply device, it is preferable that the switching control unit sequentially switches all of the plurality of coils to the transmitting coil. In this way, by setting all of the multiple coils as transmitting coils, the position and size of the target object can be detected more accurately.

[0009] As a specific embodiment of the energy supply device, it is preferable that, for one selected transmitting coil, the coils around the selected transmitting coil are sequentially switched to the receiving coils. In this way, the coils around the selected transmitting coil are sequentially set as receiving coils and their voltages or currents are detected, thereby making it possible to detect the position and size of the target more accurately.

[0010] A specific example of the energy supply device is one that includes a change rate calculation unit that calculates the rate of change from a predetermined set value of the voltage or current value of each receiving coil detected by the receiving circuit, and a determination unit that determines the type, position, and size of the target object based on the calculated change rate of the voltage or current of each receiving coil.

[0011] In the energy supply device, it is preferable that the transmission circuit and the reception circuit each include a detection resonant capacitor connected in series to the energy supply resonant capacitor. In this way, by matching the inductance and capacitance values ​​of the transmitting circuit and the receiving circuit, the resonant frequencies of the LC series resonant circuit on the transmitting circuit side and the LC parallel resonant circuit on the receiving circuit side can be matched, and by creating a configuration similar to that of a resonant type wireless power supply, the amount of change in voltage or current due to a change in inductance can be made larger.

[0012] In addition, it is preferable that the frequency of the detection signal transmitted by the transmission circuit is different from the frequency of the AC voltage supplied to the coils from the inverter circuit, so that, for example, even when some of the coils are performing a power supply operation or a heating operation, the type, position, and size of an object placed on the other coils can be detected. In this case, it is preferable that the frequency of the detection signal transmitted by the transmission circuit is 10% or more higher or 10% or more lower than the frequency of the AC voltage supplied from the inverter circuit to the coil. [Effects of the Invention]

[0013] According to the present invention configured as described above, in an energy supply device that can supply energy to an object without contact, it is possible to detect the type, position, and size of a metal object placed on the top plate. [Brief explanation of the drawings]

[0014] [Figure 1] 1 is a perspective view schematically showing a configuration of an energy supply device according to an embodiment of the present invention; [Figure 2] FIG. 2 is a plan view schematically showing the configuration of the energy supply device according to the embodiment. [Figure 3] FIG. 2 is a schematic diagram showing a circuit configuration of the energy supply device according to the embodiment; [Figure 4] FIG. 2 is a schematic diagram showing a circuit configuration of the energy supply device according to the embodiment; [Figure 5] 4 is a flowchart showing an example of control in an induction heating mode of the control device of the embodiment. [Figure 6] 10 is a flowchart showing an example of control in a wireless power supply mode of the control device of the embodiment. [Figure 7] 6 is a flowchart showing an example of control performed by the control device of the embodiment when detecting an object. [Figure 8] FIG. 2 is a schematic diagram showing a circuit configuration of the energy supply device according to the embodiment. [Figure 9] FIG. 2 is a schematic diagram showing a circuit configuration of the energy supply device according to the embodiment. [Figure 10] FIG. 2 is a schematic diagram showing a circuit configuration of the energy supply device according to the embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0015] An energy supply device 100 according to one embodiment of the present invention will be described below with reference to the drawings.

[0016] <Device configuration> The energy supplying device 100 of this embodiment supplies energy such as electric power or heat to an object O in a non-contact manner using the principle of electromagnetic induction. The energy supplying device 100 is used, for example, in a kitchen or the like, as a home appliance for induction heating metal cooking utensils such as pots and frying pans, and for wirelessly supplying power to electrical appliances such as electric kettles.

[0017] 1, this energy supply device 100 includes a top plate 1 on which an object O such as a cooking utensil or an electrical appliance is placed, a plurality of coils 2 arranged below the top plate 1 and supplying energy to the object O, energy supply resonant capacitors 3 connected in series to each of the coils 2, inverter circuits 4 supplying AC current to each of the coils 2, and a control device 5 controlling each of the inverter circuits 4. This energy supply device 100 can perform both an induction heating operation for induction heating a cooking utensil and a power supply operation for wirelessly supplying power to an electrical appliance, and is configured so that these operations can be selectively switched by the user operating a switch (not shown).

[0018] The top plate 1 is in the form of a plate having a flat mounting surface 11 on which an object O is placed. The top plate 1 is made of an electrically insulating material such as glass or ceramic.

[0019] The coil 2 functions as a heating coil during induction heating operation and as a power supply coil during power supply operation. Specifically, each coil 2 is disposed on the back side of the mounting surface 11 (below the top plate 1), and is a solenoid type configured by winding a conductor around a magnetic core made of a magnetic material such as ferrite. Here, each coil 2 is configured such that the conductor is wound around an axis perpendicular to the mounting surface 11. In other words, each coil 2 is set so that its axis is parallel to the vertical direction. As shown in FIG. 2, the multiple coils 2 all have the same shape and size, and are arranged in a two-dimensional array (vertical and horizontal matrix) in a plan view.

[0020] More specifically, in this energy supply device 100, a plurality of (five) coils 2 are arranged in rows at equal intervals to form a set of coil arrays 2A, and these coil arrays 2A are arranged in multiple rows (six rows) parallel to each other. In a plan view, each coil array 2A is arranged so that the coils 2 in adjacent rows are staggered. Here, the magnetic core 21 is shared between the plurality of coils 2 adjacent to each other. More specifically, in each coil array 2A, the magnetic core 21 is shared between the plurality of coils 2 in the row.

[0021] 3, the energy supply resonant capacitor 3 is connected in series to the coil 2 to form a resonant circuit (LC series resonant circuit). The energy supply resonant capacitor 3 is connected to each of the multiple coils 2 individually.

[0022] The inverter circuit 4 converts the AC voltage supplied from the power source into an arbitrary frequency and outputs it to the coil 2. The energy supply device 100 of this embodiment includes a plurality of inverter circuits 4 corresponding to the plurality of coils 2, respectively, and the inverter circuits 4 are connected in a one-to-one correspondence with all of the arranged coils 2. The inverter circuits 4 are of a half-bridge type using semiconductor switching elements, but are not limited to this and may be of a full-bridge type.

[0023] The control device 5 is a computer equipped with a CPU, memory, input means, etc. The control device 5 operates in accordance with a predetermined program stored in its memory, thereby fulfilling at least the function of an inverter circuit control unit 51 that individually controls each inverter circuit 4, as shown in FIG.

[0024] Specifically, the inverter circuit control unit 51 is configured to individually control the operation of the inverter circuits 4 connected to each coil 2, thereby individually adjusting the on / off, frequency (for example, from a low frequency band of 3 kHz or less to a high frequency band of 10 kHz to 100 kHz), phase, and voltage of the current flowing to each coil 2. The inverter circuit control unit 51 is also configured to individually change the direction of the magnetic flux generated from each coil 2 by changing the direction of the current flowing to each coil 2. In this embodiment, the inverter circuit control unit 51 is configured to selectively energize only the coil 2 located below the object O placed on the top plate 1.

[0025] 5 and 6, the inverter circuit control unit 51 can take two control modes: an induction heating mode in which each inverter circuit 4 is controlled to induction heat the object O placed on the top plate 1, and a power supply mode in which each inverter circuit 4 is controlled to supply power to the object O. The inverter circuit control unit 51 switches between the induction heating mode and the power supply mode by switching the direction of the current flowing through each coil 2. Each mode will now be described.

[0026] (induction heating mode) First, when the power is turned on by a user's input operation and induction heating mode (IH heating mode) is selected, control device 5 determines whether there is a metal object on top plate 1, whether the metal object is a heating target, the size and position of the heating target, and determines coil 2 to be used for induction heating. Then, when the heating power is set by the user's input operation, heating of the heating target begins.

[0027] Specifically, in this induction heating mode, the inverter circuit control unit 51 controls each inverter circuit 4 so that the directions of magnetic flux generated from adjacent coils 2 are opposite to each other. More specifically, in each coil array 2A, the directions of current flowing through adjacent coils 2 are opposite to each other, and each inverter circuit 4 is controlled so that the directions of magnetic flux generated from these coils 2 are opposite to each other. In this induction heating mode, the inverter circuit control unit 51 controls each inverter circuit 4 so that a high-frequency current of, for example, 10 kHz or higher flows through each coil 2.

[0028] (Power supply mode) First, when the user turns on the power and selects wireless power supply mode, control device 5 communicates with the power supply target via NFC (near field communication) and requests the power supply target to connect a resonant capacitor. Control device 5 then determines whether there is a metal object on top plate 1, whether the metal object is a power supply target, and the size and position of the power supply target. Control device 5 then determines coil 2 to be used for power supply and starts power supply to the power supply target.

[0029] Specifically, in this power supply mode, the inverter circuit control unit 51 controls each inverter circuit 4 so that the direction of magnetic flux in the coil 2 within the power supply target and the coil 2 surrounding it are opposite to each other. More specifically, each inverter circuit 4 is controlled so that the direction of magnetic flux in the coil 2 within the power supply target and the coil 2 surrounding it are opposite to each other, and the directions of magnetic flux generated from these coils 2 are opposite to each other. In this power supply mode, the inverter circuit control unit 51 controls each inverter circuit 4 so that a high-frequency current of, for example, 10 kHz or higher flows through each coil 2. An AC voltage is applied from the inverter 3 to each coil 2, causing it to generate an oscillating magnetic field.

[0030] An example of the object O to which power can be supplied in the power supply mode is one that includes a load and a power receiving unit that receives power transmitted from the energy supply device 100 and outputs it to the load. An example of this power receiving unit is one that includes a secondary-side resonant circuit that magnetically resonates with the resonant circuit of the energy supply device 100 (a coil 2 and an energy supply resonant capacitor 3 connected in series to each other) to generate an AC voltage, and a voltage conversion circuit that converts the AC voltage output from the secondary-side resonant circuit into a desired voltage and supplies it to the load. An example of the secondary-side resonant circuit is an LC series resonant circuit that is configured of a secondary-side coil and a secondary-side resonant capacitor connected in series to each other.

[0031] Thus, the energy supply device 100 of this embodiment includes a detection circuit 6 for detecting the type, position, and size of an object O placed on the top plate 1. As shown in Fig. 3, this detection circuit 6 includes a transmission circuit 61 that transmits a detection signal of a predetermined frequency to one of the multiple coils 2, and a reception circuit 62 that detects a current or voltage induced in any of the other coils 2 different from the coil 2 in question in response to the transmitted detection signal.

[0032] In this embodiment, a detection circuit 6 is connected to each of the multiple coils 2. Specifically, the detection circuit 6 is connected in series to the coils 2 via an openable / closable switch SW1. The switch SW1 is a so-called double-throw switch, and is configured to be able to switch the circuit connected to the coils 2 between the detection circuit 6 and the inverter circuit 4.

[0033] As shown in FIG. 4, the transmission circuit 61 outputs a detection signal, which is a rectangular wave signal with a predetermined frequency, to the coil 2. The frequency of this detection signal is different from the frequency of the AC voltage supplied from the inverter circuit 4 to the coil 2 in the induction heating mode and the power supply mode. More specifically, the frequency is set to be 10% or more higher or lower than the frequency of the AC voltage supplied from the inverter circuit 4 to the coil 2. Specifically, the transmission circuit 61 includes a driver 61a, a resistor 61b (current-limiting resistor), and a detection resonance capacitor 61c, all of which are connected in series to the coil 2. The transmission circuit 61 is connected to the coil 2 via an open / close switch SW2 such as a semiconductor switch. Furthermore, multiple transmission circuits 61 are connected to a selector switch, and the coil 2 to which the detection signal is transmitted is switched by switching the selector switch in response to a control signal output from the control device 5.

[0034] When the transmitter circuit 61 transmits a detection signal to a coil 2, the receiver circuit 62 detects a current or voltage induced in another coil 2 that magnetically resonates with the detection signal. Specifically, the receiver circuit 62 includes a resistor and a detection resonance capacitor 62b, both of which are connected in series to the coil 2 and in parallel with each other. The receiver circuit 62 is connected to the coil 2 via an open / close switch SW3 such as a semiconductor switch. In this configuration, the multiple receiver circuits 62 are connected to a selector switch, and the selector switch is switched in response to a control signal output from the control device 5, thereby switching the coil 2 whose voltage or current is to be detected.

[0035] The control device 5 of this embodiment is configured to determine the type, position, and size of the object O placed on the top plate 1, as shown in the flowchart of Figure 7, and further performs the functions of a switching control unit 52, a change rate calculation unit 53, and a judgment unit 54.

[0036] The switching control unit 52 selects and sequentially switches between a transmitting coil Tx, which is a coil 2 that transmits a detection signal using a transmitting circuit 61, and a receiving coil Rx, which is a coil 2 that detects voltage or current using a receiving circuit 62, from among multiple coils 2.

[0037] Specifically, the switching control unit 52 selects any one coil 2 as the transmitting coil Tx, and selects any one coil 2 around the transmitting coil Tx (for example, an adjacent coil) as the receiving coil Rx (steps S1 to S3). The control device 5 then transmits a detection signal of a predetermined frequency to the transmitting coil Tx using the transmitting circuit 61, and detects the voltage or current of the receiving coil Rx using the receiving circuit 62 (steps S4 and S5). The switching control unit 52 then selects another coil 2 around the transmitting coil Tx as the receiving coil Rx, and similarly detects the voltage or current of the receiving coil Rx (step S7). The switching control unit 52 switches the receiving coils Rx one by one until it has detected the voltages or currents of all coils 2 around the transmitting coil Tx (for example, adjacent coils).

[0038] Then, when the switching control unit 52 detects the voltage or current of all the receiving coils Rx around the selected transmitting coil Tx, it selects another coil 2 as the transmitting coil Tx (steps S8 and S9) and repeats the above steps S2 to S7. In this way, the switching control unit 52 switches the coils 2 one by one in order until all of the multiple coils 2 are selected as transmitting coils Tx.

[0039] The change rate calculation unit 53 compares the voltage or current value of each receiving coil Rx detected by the receiving circuit 62 with a predetermined set value pre-stored in memory, and calculates the rate of change [%] from the set value. Specifically, this predetermined set value is the voltage or current value of each receiving coil Rx when no object O is placed on the top plate 1. Specifically, the change rate calculation unit 53 calculates the rate of change of the voltage or current values ​​of all receiving coils Rx detected by the receiving circuit 62 with respect to the set value (step S10).

[0040] The determination unit 54 determines the type, position, and size of the object O placed on the top plate 1 based on the rate of change of the voltage or current value of each receiving coil Rx calculated by the change rate calculation unit 53. Specifically, as shown in Fig. 7, the determination unit 54 compares the rate of change of the voltage or current in each receiving coil Rx with a plurality of preset thresholds (α, β, γ), determines whether the object placed on the top plate 1 is a power supply object, a heating object, or a metallic foreign object, and determines the position and size of the object if it is determined to be a power supply object or a heating object (steps S11 to S17).

[0041] Specifically, the judgment unit 54 pre-stores a first threshold α [%], a second threshold β [%], and a third threshold γ [%] (-β<-α<-γ. β: approximately 95%, α: approximately 30%, γ: approximately 10%), and makes the above judgment based on these three thresholds.

[0042] More specifically, if there is a receiving coil Rx with a rate of change ≦−β, the determination unit 54 determines that the heating target is on that receiving coil Rx. Then, the determination unit 54 determines the size and center position of the heating target based on the number of receiving coils Rx with a rate of change ≦−β, and determines the coil 2 to be used for heating (steps S11, S12, S13).

[0043] Furthermore, if there is a receiving coil Rx where -β<rate of change≦-α, the determination unit 54 determines that a power supply target exists on that receiving coil Rx. Then, the determination unit 54 determines the size and central position of the power supply target based on the number of receiving coils Rx where -β<rate of change≦-α, and determines the coil 2 to be used for power supply (steps S11, S12, S14).

[0044] Furthermore, if there is a receiving coil Rx where -α< rate of change≦-γ, the judgment unit 54 judges that there is a metal foreign object on the receiving coil Rx (steps S11, S13, S16), and if there is a receiving coil Rx where -γ< rate of change, the judgment unit 54 judges that there is no metal object on the receiving coil Rx (steps S11, S13, S17).

[0045] <Effects of this embodiment> According to the energy supply device 100 of the present embodiment configured as described above, the switching control unit 52 is configured to select and sequentially switch between a transmitting coil Tx that transmits a detection signal via the transmitting circuit 61 and a receiving coil Rx that detects a voltage or current via the receiving circuit 62 from the multiple coils 2, so that the multiple coils 2 arranged below the top plate 1 can be used as both transmitting coils Tx and receiving coils Rx. Therefore, by setting the multiple coils 2 arranged below the top plate 1 in various combinations as transmitting coils Tx and receiving coils Rx and detecting the voltage or current from each receiving coil Rx in response to the detection signal, the type, position, and size of the object O placed on the top plate 1 can be detected.

[0046] <Other Modified Embodiments> The present invention is not limited to the above-described embodiment.

[0047] For example, in the above embodiment, the detection circuit 6 and the inverter circuit 4 are switchably connected by the switch SW1, but this is not limiting. In another embodiment, as shown in Fig. 8, the inverter circuit 4 may be constantly connected to the coil 2, and the detection circuit 6 may be connected to the coil 2 via the ON / OFF switch SW4. In this way, the ON / OFF switch SW4 is not used to turn on and off the current in the inverter circuit 4, so the ON / OFF switch SW4 can be made smaller, and the inverter circuit 4 can be made thinner.

[0048] In the above embodiment, the detection circuits 6 (transmitting circuit 61 and receiving circuit 62) are individually connected to each coil 2, but this is not limited thereto. In another embodiment, as shown in FIG. 9, the transmitting circuit 61 and receiving circuit 62 may be configured to be shared among multiple coils 2. Specifically, in this embodiment, one transmitting circuit 61 and one receiving circuit 62 may be configured to be connected to multiple coils 2 via a selector switch. The switching control unit 52 may then switch between the coil 2 that transmits the detection signal and the coil 2 that detects the voltage or current by switching the selector switch. This can reduce the number of components, such as the driver 61a and the detection resonant capacitors 61c and 62b, and their peripheral circuits.

[0049] In the above embodiment, the transmission circuit 61 and the reception circuit 62 are provided with the detection resonant capacitors 61c and 62b, but this is not limited to this. In other embodiments, the transmission circuit 61 and the reception circuit 62 may not be provided with the detection resonant capacitors 61c and 62b. For example, as shown in Fig. 10, if the inverter circuit 4 can be disconnected from the coil 2 by the switch SW1, the energy supply resonant capacitor 3 can be used also as a resonant capacitor for detecting the object O.

[0050] In addition, various modifications and combinations of the embodiments may be made as long as they do not go against the spirit of the present invention. [Explanation of symbols]

[0051] 100 Energy supply device 1 Top Plate 2. Coil 3. Energy supply resonant capacitor 4. Inverter circuit 5. Control equipment 52 Switching control section 6. Detection circuit 61 Transmitting circuit 62 Receiving circuit O Object

Claims

1. An energy supply device that supplies energy to an object placed on a top plate in a non-contact manner, a plurality of coils arranged side by side under the top plate to supply energy to the object, the coils being connected to an energy supply resonant capacitor and an inverter circuit; a transmission circuit for transmitting a detection signal of a predetermined frequency to any one of the plurality of coils; a receiving circuit that, in response to the transmitted detection signal, detects a voltage or a current induced in any of the coils other than the coil from which the detection signal is transmitted; An energy supply device comprising a switching control unit that selects a transmitting coil that transmits the detection signal and a receiving coil that detects the voltage or current from the plurality of coils arranged in a row under the top plate, and switches between them sequentially.

2. The energy supply device according to claim 1 , wherein the switching control unit sequentially switches all of the plurality of coils to the transmitting coil.

3. The energy supply device according to claim 1 or 2, wherein the switching control unit sequentially switches the coils around the selected one of the transmitting coils to the receiving coil.

4. a change rate calculation unit that calculates a change rate from a predetermined set value of the voltage or current value of each of the receiving coils detected by the receiving circuit; The energy supply device according to any one of claims 1 to 3, further comprising: a determination unit that determines the type, position, and size of the object based on the calculated rate of change of the voltage or current of each receiving coil.

5. 5. The energy supply device according to claim 1, wherein the transmission circuit and the reception circuit each include a detection resonant capacitor connected in series with the energy supply resonant capacitor.

6. The energy supply device according to any one of claims 1 to 5, wherein the frequency of the detection signal transmitted by the transmission circuit is different from the frequency of the AC voltage supplied from the inverter circuit to the coil.

7. The energy supply device according to claim 6 , wherein the frequency of the detection signal transmitted by the transmission circuit is 10% or more higher or 10% or more lower than the frequency of the AC voltage supplied from the inverter circuit to the coil.

Images