Electromagnetic heating circuit and heating equipment

Abstract

The invention provides an electromagnetic heating circuit and heating equipment. The electromagnetic heating circuit comprises N resonance circuits and (N + 1) bridge arm circuits, the (N + 1) bridge arm circuits are arranged in parallel and staggered with the N resonance circuits, the two ends of each resonance circuit are connected with the middle output ends of the two adjacent bridge arm circuits respectively, and the first resonance circuit is not connected with the (N + 1) th resonance circuit; wherein N is greater than or equal to 3. According to the electromagnetic heating circuit provided by the invention, the cost can be reduced, and the application scene of the electromagnetic heating circuit is enhanced.

Description

Technical Field

[0001] This application relates to the field of home appliance technology, and in particular to an electromagnetic heating circuit and heating device. Background Technology

[0002] Existing electromagnetic heating circuits that utilize electromagnetic technology to achieve heating functions employ multiple coils for heating, enabling multi-zone heating of the equipment. However, since multiple coils share a single drive circuit, the output power of the coils cannot be independently adjusted. Summary of the Invention

[0003] This application provides an electromagnetic heating circuit and heating device to solve the technical problem that the output power of the resonant circuit in existing electromagnetic heating circuits cannot be independently adjusted.

[0004] To solve the above-mentioned technical problems, this application provides an electromagnetic heating circuit, which includes N resonant circuits and (N+1) bridge arm circuits. The (N+1) bridge arm circuits are arranged in parallel and interleaved with the N resonant circuits. The two ends of each resonant circuit are respectively connected to the middle output terminals of two adjacent bridge arm circuits, and the first resonant circuit is not connected to the (N+1)th resonant circuit; wherein, N is greater than or equal to 3.

[0005] In one embodiment, the (N+1) bridge arm circuits include at least a first bridge arm circuit, a second bridge arm circuit, a third bridge arm circuit, and a fourth bridge arm circuit arranged in parallel, and the N resonant circuits include at least a first resonant circuit, a second resonant circuit, and a third resonant circuit, wherein the first resonant circuit is connected in series between the intermediate output terminals of the first and second bridge arm circuits; the second resonant circuit is connected in series between the intermediate output terminals of the second and third bridge arm circuits; and the third resonant circuit is connected in series between the intermediate output terminals of the third and fourth bridge arm circuits.

[0006] In one embodiment, the electromagnetic heating circuit is configured with a first operating mode. When the electromagnetic heating circuit is in the first operating mode, the first resonant circuit, the second resonant circuit, and the third resonant circuit are simultaneously in operation. The first resonant circuit and the second resonant circuit share a second bridge arm circuit, and the second resonant circuit and the third resonant circuit share a third bridge arm circuit. Thus, the first resonant circuit, the second resonant circuit, and the third resonant circuit are driven by their respective full-bridge drive circuits. When the first bridge arm circuit, the fourth bridge arm circuit, and the shared bridge arm circuit are connected to the corresponding drive signal, they drive the corresponding resonant circuits to operate.

[0007] In one embodiment, the electromagnetic heating circuit is configured with a second operating mode. When the electromagnetic heating circuit is in the second operating mode, the first resonant circuit, the second resonant circuit, and the third resonant circuit are all in operation at the same time, and two non-adjacent bridge arm circuits are used as shared bridge arm circuits. Thus, the first resonant circuit, the second resonant circuit, and the third resonant circuit are driven by the corresponding half-bridge driving circuits. When the shared bridge arm circuit is connected to a conduction signal, and the non-shared bridge arm circuit is connected to the corresponding driving signal, the corresponding resonant circuit is driven to work.

[0008] In one embodiment, the electromagnetic heating circuit is configured with a third operating mode. When the electromagnetic heating circuit is in the third operating mode, the first resonant circuit, the second resonant circuit, and the third resonant circuit are all in operation at the same time, and any one of the middle bridge arm circuits is used as a shared bridge arm circuit, so that the first bridge arm circuit, the second bridge arm circuit, the third bridge arm circuit, and the fourth bridge arm circuit constitute two half-bridge driving circuits and one full-bridge driving circuit. Thus, two of the resonant circuits are driven by the corresponding half-bridge driving circuits, and the remaining resonant circuit is driven by the corresponding full-bridge driving circuit. The shared bridge arm circuit is connected to the conduction signal, and the non-shared bridge arm circuit is connected to the corresponding driving signal.

[0009] In one embodiment, the electromagnetic heating circuit is configured with a fourth operating mode. When the electromagnetic heating circuit is in the fourth operating mode, any one of the first resonant circuit, the second resonant circuit, or the third resonant circuit is in an operating state. In this mode, the bridge arm circuits at both ends of the resonant circuit in the operating state are connected to the corresponding driving signal, and the resonant circuit in the operating state is driven by the full-bridge driving circuit. Alternatively, in the operating state, the bridge arm circuit at one end of the resonant circuit is connected to the corresponding driving signal, and the bridge arm circuit at the other end is connected to the conduction signal, and the resonant circuit in the operating state is driven by the half-bridge driving circuit.

[0010] In one embodiment, the electromagnetic heating circuit is configured with a fifth operating mode. When the electromagnetic heating circuit is in the fifth operating mode, any two of the first resonant circuit, the second resonant circuit, or the third resonant circuit are in an operating state. When two adjacent resonant circuits are in an operating state, the bridge arm circuits connected to both adjacent resonant circuits serve as shared bridge arm circuits. The shared bridge arm circuit and the two bridge arm circuits adjacent to the shared bridge arm circuit are connected to corresponding drive signals, and the two adjacent resonant circuits are driven by corresponding full-bridge drive circuits. Alternatively, when two adjacent resonant circuits are in an operating state, the bridge arm circuits connected to both adjacent resonant circuits serve as shared bridge arm circuits. In this configuration, the shared bridge arm circuit is connected to a conduction signal, and the two bridge arm circuits adjacent to the shared bridge arm circuit are connected to corresponding drive signals. The two adjacent resonant circuits are driven by the corresponding half-bridge drive circuit. Alternatively, when the two adjacent resonant circuits are in operation, the bridge arm circuits connected to both adjacent resonant circuits serve as the shared bridge arm circuit. In this configuration, one of the two adjacent bridge arm circuits of the shared bridge arm circuit and the shared bridge arm circuit are connected to corresponding drive signals, and the other of the two adjacent bridge arm circuits of the shared bridge arm circuit is connected to a conduction signal. One of the resonant circuits is driven by the corresponding half-bridge drive circuit, and the other resonant circuit is driven by the corresponding full-bridge drive circuit.

[0011] In one embodiment, the electromagnetic heating circuit is configured with a sixth operating mode. When the electromagnetic heating circuit is in the sixth operating mode, the first resonant circuit and the third resonant circuit are in operation. The second bridge arm circuit and the third bridge arm circuit are used to receive the same conduction signal, and the first bridge arm circuit and the fourth bridge arm circuit are used to receive corresponding drive signals. Alternatively, the second bridge arm circuit and the third bridge arm circuit are used to receive the same drive signal, and the first bridge arm circuit and the fourth bridge arm circuit are used to receive corresponding drive signals.

[0012] In one embodiment, the bridge arm circuit includes: a first switch, the first terminal of which is connected to a positive power supply voltage, the control terminal of which is connected to a control signal, and the second terminal of which serves as an intermediate output terminal; and a second switch, the first terminal of which is connected to the second terminal of the first switch, the control terminal of which is connected to a control signal, and the second terminal of which is grounded.

[0013] This application also provides a heating device, which includes the electromagnetic heating circuit of any of the above embodiments, wherein the heating device includes multiple heating zones, and each heating zone includes one or more coils of resonant circuits.

[0014] The beneficial effects of this application are as follows: The electromagnetic heating circuit of this application includes N resonant circuits and (N+1) bridge arm circuits. The (N+1) bridge arm circuits are arranged in parallel and interleaved with the N resonant circuits. The two ends of each resonant circuit are respectively connected to the middle output terminals of two adjacent bridge arm circuits, and the first resonant circuit is not connected to the (N+1)th resonant circuit; wherein, N is greater than or equal to 3. Unlike the prior art, the (N+1) bridge arm circuits of this application are arranged in parallel and interleaved with the N resonant circuits, allowing the middle bridge arm circuit to be reused by the resonant circuits at its two ends. Furthermore, the two ends of each resonant circuit are respectively connected to two different bridge arm circuits, ensuring that at least some of the full-bridge drive circuits or half-bridge drive circuits of the resonant circuits are not shared, thereby achieving independent adjustment of the output power of the resonant circuits. Attached Figure Description

[0015] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort, wherein:

[0016] Figure 1 This is a circuit diagram of an embodiment of the electromagnetic heating circuit provided in this application;

[0017] Figure 2 This is a circuit diagram of another embodiment of the electromagnetic heating circuit provided in this application;

[0018] Figure 3 This is a driving timing diagram of an embodiment of the electromagnetic heating circuit provided in this application when it is in the first working mode;

[0019] Figure 4 This is a driving timing diagram of an embodiment of the electromagnetic heating circuit provided in this application when it is in the fourth working mode;

[0020] Figure 5 This is a schematic diagram of the driving timing of an embodiment of the electromagnetic heating circuit provided in this application when it is in the fifth working mode.

[0021] Figure label:

[0022] 10 Electromagnetic heating circuit; 110 Bridge arm circuit; 111 First bridge arm circuit; 112 Second bridge arm circuit; 113 Third bridge arm circuit; 114 Fourth bridge arm circuit; 120 Resonant circuit; 121 First resonant circuit; 122 Second resonant circuit; 123 Third resonant circuit; M1 First switching transistor; M2 Second switching transistor. Detailed Implementation

[0023] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of the embodiments. Based on the embodiments of this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this application.

[0024] It should be noted that if the embodiments of this application involve directional indicators (such as up, down, left, right, front, back, etc.), the directional indicators are only used to explain the relative positional relationship and movement of the components in a certain specific posture (as shown in the figure). If the specific posture changes, the directional indicators will also change accordingly.

[0025] Furthermore, if the embodiments of this application involve descriptions such as "first" or "second," these descriptions are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, features defined with "first" or "second" may explicitly or implicitly include at least one of those features. Additionally, the technical solutions of various embodiments can be combined with each other, but this must be based on the ability of those skilled in the art to implement them. If the combination of technical solutions is contradictory or impossible to implement, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection claimed in this application.

[0026] Existing electromagnetic heating circuits that utilize electromagnetic technology to achieve heating functions employ multiple coils or resonant circuits for heating, enabling multi-zone heating of the device. However, sharing a single drive circuit among multiple coils presents a technical problem: the output power of the coils cannot be independently adjusted. Alternatively, each coil may have its own independent drive circuit. If this independent drive circuit is a half-bridge drive circuit, it suffers from a narrow output power range. If the independent drive circuit is a full-bridge drive circuit, it presents a high cost problem.

[0027] To address the aforementioned technical problems, this application provides an electromagnetic heating circuit. The output power of the resonant circuit in this electromagnetic heating circuit can be independently adjusted, and it also features a wide output power range and low cost. Furthermore, the electromagnetic heating circuit of this application can be applied to heating devices that utilize electromagnetic technology to achieve heating functions. Specifically, the heating device can be an electric rice cooker with electromagnetic induction heating, an induction cooker, etc., and is not limited thereto.

[0028] See Figure 1 , Figure 1This is a circuit diagram of an embodiment of the electromagnetic heating circuit provided in this application. The electromagnetic heating circuit 10 includes N resonant circuits 120 and (N+1) bridge arm circuits 110. The (N+1) bridge arm circuits 110 are connected in parallel and alternately arranged with the N resonant circuits 120. The two ends of each resonant circuit 120 are connected to the middle output terminals of two adjacent bridge arm circuits 110, and the first resonant circuit 120 is not connected to the (N+1)th resonant circuit 120. N is greater than or equal to 3.

[0029] N can be 3, 4, 5, 6, 7, etc., and N can be configured according to the specific resonant circuit 120 required for heating. (N+1) bridge arm circuits 110 are connected in parallel and interleaved with the N resonant circuits 120, allowing the resonant circuit 120 to be driven by a full-bridge drive circuit (not shown) or a half-bridge drive circuit (not shown) composed of the bridge arm circuits 110 directly connected to it. When the resonant circuit 120 is working, it can efficiently convert electrical energy into magnetic field energy. The magnetic field provided by the resonant circuit 120 can penetrate the device to be heated, such as a pot, causing eddy currents to be generated inside the device, thereby converting electrical energy into heat energy and heating the device.

[0030] Unlike existing technologies, this application features (N+1) bridge arm circuits 110 connected in parallel and interleaved with N resonant circuits 120. This allows the middle bridge arm circuit 110 to be reused by the resonant circuits 120 connected to it at both ends. Furthermore, each resonant circuit 120 has two different bridge arm circuits 110 connected to its ends, ensuring that at least some of the full-bridge or half-bridge drive circuits of the resonant circuits 120 are not shared (e.g., the bridge arm circuits used for driving are not shared, or the bridge arm circuits used for conduction paths are not shared). This enables independent adjustment of the output power of the resonant circuits 120. Additionally, by reusing the bridge arm circuits 110, the driving circuit of this application reduces the number of bridge arm circuits 110, thereby lowering the cost of the electromagnetic heating circuit 10. Moreover, the resonant circuits 120 can be driven by either half-bridge or full-bridge drive circuits, thus broadening the range of their output power.

[0031] In one embodiment, see Figure 2 , Figure 2 This is a circuit diagram of another embodiment of the electromagnetic heating circuit provided in this application. The resonant circuit 120 includes a coil and a capacitor, which are connected in series. The coil can be equivalent to an inductor and a resistor connected in series.

[0032] In one embodiment, see Figure 2Each bridge arm circuit 110 includes a first switch M1 and a second switch M2. The first terminal of the first switch M1 is connected to the positive input terminal of the power supply, and a control signal is received at the control terminal of the first switch M1. The second terminal of the first switch M1 is connected to the first terminal of the second switch M2, and a control signal is received at the control terminal of the second switch M2. The second terminal of the second switch M2 is grounded. The branch connecting the second terminal of the first switch M1 and the first terminal of the second switch M2 serves as the intermediate output terminal of the bridge arm circuit 110 and is connected to the resonant circuit 120. The first switch M1 and the second switch M2 can be power MOSFETs or IGBTs, which are not limited here. The control signal can be a turn-on signal or a drive signal. The turn-on signal can control the first switch M1 or the second switch M2 to turn on, and correspondingly control the second switch M2 or the first switch M1 to turn off. Thus, the intermediate output terminal of the bridge arm circuit 110 is grounded during the positive half-cycle of the AC power supply, and connected to the positive input terminal of the power supply during the negative half-cycle of the AC power supply. The driving signal is used to drive the resonant circuit 120 to work normally. This process is a conventional driving process and will not be described in detail here.

[0033] In one embodiment, see Figure 2 The (N+1) bridge arm circuits 110 include at least a first bridge arm circuit 111, a second bridge arm circuit 112, a third bridge arm circuit 113, and a fourth bridge arm circuit 114 connected in parallel. The N resonant circuits 120 include at least a first resonant circuit 121, a second resonant circuit 122, and a third resonant circuit 123. Specifically, the first resonant circuit 121 is connected in series between the intermediate output terminals of the first bridge arm circuit 111 and the second bridge arm circuit 112; the second resonant circuit 122 is connected in series between the intermediate output terminals of the second bridge arm circuit 112 and the third bridge arm circuit 113; and the third resonant circuit 123 is connected in series between the intermediate output terminals of the third bridge arm circuit 113 and the fourth bridge arm circuit 114.

[0034] Understandably, in this embodiment, the first resonant circuit 121 and the second resonant circuit 122 are both connected to the second bridge arm circuit 112, and the second resonant circuit 122 and the third resonant circuit 123 are both connected to the third bridge arm circuit 113. The first resonant circuit 121 and the fourth resonant circuit 120 are not connected. The electromagnetic heating circuit 10 in this embodiment is provided with three resonant circuits 120 and four bridge arm circuits 110. One or two of the four bridge arm circuits 110 can be multiplexed, so that the four bridge arm circuits 110 can form a full-bridge drive circuit, a half-bridge drive circuit, or a half-bridge drive circuit and a full-bridge drive circuit to drive the corresponding resonant circuit 120 to work, so that the output power of each resonant circuit 120 can be independently adjusted, which can adapt to the multiple application scenarios of the electromagnetic heating circuit 10.

[0035] In one embodiment, the electromagnetic heating circuit 10 is configured with a first operating mode. When the electromagnetic heating circuit 10 is in the first operating mode, the first resonant circuit 121, the second resonant circuit 122, and the third resonant circuit 123 are simultaneously in operation. The first resonant circuit 121 and the second resonant circuit 122 share the second bridge arm circuit 112, and the second resonant circuit 122 and the third resonant circuit 123 share the third bridge arm circuit 113. Thus, the first resonant circuit 121, the second resonant circuit 122, and the third resonant circuit 123 are driven by their respective full-bridge drive circuits. When the first bridge arm circuit 111, the fourth bridge arm circuit 114, and the shared bridge arm circuit 110 receive their respective drive signals, they drive the corresponding resonant circuit 120 to operate.

[0036] Understandably, when the electromagnetic heating circuit 10 is in the first operating mode, all three resonant circuits 120 are in operation, and the driving circuit of each resonant circuit 120 is a full-bridge driving circuit. Specifically, the first bridge arm circuit 111 and the second bridge arm circuit 112 constitute a full-bridge driving circuit driving the first resonant circuit 121; the second bridge arm circuit 112 and the third bridge arm circuit 113 constitute a full-bridge driving circuit driving the second resonant circuit 122; and the third bridge arm circuit 113 and the fourth bridge arm circuit 114 constitute a full-bridge driving circuit driving the third resonant circuit 123. When the three full-bridge driving circuits operate at the same frequency, the independent adjustment of the duty cycle of each of the three resonant circuits 120 can be achieved. The operating mode of the electromagnetic heating circuit 10 in this embodiment can meet the application scenario where all three resonant circuits 120 are high-power outputs.

[0037] See Figure 3 , Figure 3This is a schematic diagram of the driving timing of an embodiment of the electromagnetic heating circuit provided in this application when it is in the first working mode. Each bridge arm circuit 110 includes a first switch M1 and a second switch M2. The control terminal of the first switch M1 in the first bridge arm circuit 111 is S1, and the control terminal of the second switch M2 is S2; the control terminal of the first switch M1 in the second bridge arm circuit 112 is S3, and the control terminal of the second switch M2 is S4; the control terminal of the first switch M1 in the third bridge arm circuit 113 is S5, and the control terminal of the second switch M2 is S6; the control terminal of the first switch M1 in the fourth bridge arm circuit 114 is S7, and the control terminal of the second switch M2 is S8. Each control terminal is connected to a corresponding driving signal. The duty cycle of the voltage of the first resonant circuit 121, or the output voltage of the first bridge arm circuit 111 and the second bridge arm circuit 112, is adjusted by the phase difference between the first bridge arm circuit 111 and the second bridge arm circuit 112 (the shift phase of the second bridge arm circuit 112 relative to the first bridge arm circuit 111). The duty cycle of the output voltage of the second resonant circuit 122 and the third resonant circuit 123 can also be adjusted in this manner. In this embodiment, the control terminals of the first switch M1 and the second switch M2 are turned on when receiving a high level and turned off when receiving a low level; alternatively, the control terminals of the first switch M1 and the second switch M2 are turned on when receiving a low level and turned off when receiving a high level, without limitation.

[0038] In one embodiment, the electromagnetic heating circuit 10 is configured with a second operating mode. When the electromagnetic heating circuit 10 is in the second operating mode, the first resonant circuit 121, the second resonant circuit 122, and the third resonant circuit 123 are simultaneously in operation, and two non-adjacent bridge arm circuits 110 serve as shared bridge arm circuits 110. Thus, the first resonant circuit 121, the second resonant circuit 122, and the third resonant circuit 123 are driven by their respective half-bridge drive circuits. Specifically, when the shared bridge arm circuit 110 receives a conduction signal, and when the non-shared bridge arm circuit 110 receives its corresponding drive signal, it drives the corresponding resonant circuit 120 to operate.

[0039] Understandably, when all three resonant circuits 120 in this embodiment are in operation, the driving circuits for all three resonant circuits 120 are half-bridge driving circuits. Two non-adjacent bridge arm circuits 110 serve as shared bridge arm circuits 110, with the shared bridge arm circuit 110 receiving a conduction signal, and the non-shared bridge arm circuit 110 receiving a corresponding driving signal. When a bridge arm circuit 110 receives a conduction signal, its intermediate output point is always connected to a certain terminal of the power supply. For example, during the positive half-cycle of the AC power supply, the intermediate output point of the shared bridge arm circuit 110 is always grounded; during the negative half-cycle of the AC power supply, the intermediate output point is always connected to the positive output terminal. In other words, the shared bridge arm circuit 110 serves as the conduction path when receiving a conduction signal. The non-shared bridge arm circuit 110 receives its corresponding driving signal to drive the corresponding resonant circuit 120. The operating mode of the electromagnetic heating circuit 10 in this embodiment can meet the application scenario where all three resonant circuits 120 are low-power output.

[0040] For example, when the second bridge arm circuit 112 and the fourth bridge arm circuit 114 are shared as a bridge arm circuit 110, the first bridge arm circuit 111 serves as a half-bridge driving circuit for driving the first resonant circuit 121, and the third bridge arm circuit 113 serves as a half-bridge driving circuit for driving the second resonant circuit 122 and the third resonant circuit 123. When the first bridge arm circuit 111 and the third bridge arm circuit 113 are shared as a bridge arm circuit 110, the second bridge arm circuit 112 serves as a half-bridge driving circuit for driving the first resonant circuit 121 and the third resonant circuit 123, and the fourth bridge arm circuit 114 serves as a half-bridge driving circuit for driving the third resonant circuit 123.

[0041] In one embodiment, the electromagnetic heating circuit 10 is configured with a third operating mode. When the electromagnetic heating circuit 10 is in the third operating mode, the first resonant circuit 121, the second resonant circuit 122, and the third resonant circuit 123 are all in operation at the same time, and any one of the middle bridge arm circuits 110 serves as a shared bridge arm circuit 110, so that the first bridge arm circuit 111, the second bridge arm circuit 112, the third bridge arm circuit 113, and the fourth bridge arm circuit 114 constitute two half-bridge driving circuits and one full-bridge driving circuit. Thus, two of the resonant circuits 120 are driven by the corresponding half-bridge driving circuits, and the remaining resonant circuit 120 is driven by the corresponding full-bridge driving circuit. When the shared bridge arm circuit 110 receives a conduction signal, and when the non-shared bridge arm circuit 110 receives the corresponding driving signal, it drives the corresponding resonant circuit 120 to work.

[0042] Understandably, in this embodiment, two of the three resonant circuits 120 can be driven by a half-bridge drive circuit, while the remaining resonant circuit 120 can be driven by a full-bridge drive circuit. Specifically, any middle bridge arm circuit 110, such as the second bridge arm circuit 112 or the third bridge arm circuit 113, serves as a shared bridge arm circuit 110, and this shared bridge arm circuit 110 is connected to a conduction signal as a conduction branch. The remaining non-shared bridge arm circuits 110 are connected to their respective drive signals to drive their corresponding resonant circuits 120. The operating mode of the electromagnetic heating circuit 10 in this embodiment can meet the application scenarios of both high-power and low-power output for the three resonant circuits 120.

[0043] For example, when the second bridge arm circuit 112 is used as a shared bridge arm circuit 110, the first bridge arm circuit 111 can be used as a half-bridge drive circuit of the first resonant circuit 121, the third bridge arm circuit 113 can be used as a half-bridge drive circuit of the second resonant circuit 122, and the third bridge arm circuit 113 and the fourth bridge arm circuit 114 can be used as a full-bridge drive circuit of the third resonant circuit 123.

[0044] In one embodiment, the electromagnetic heating circuit 10 is configured with a fourth operating mode. When the electromagnetic heating circuit 10 is in the fourth operating mode, any one of the first resonant circuit 121, the second resonant circuit 122, or the third resonant circuit 123 is in an operating state. When the bridge arm circuits 110 at both ends of the resonant circuit 120 in the operating state are connected to the corresponding driving signal, the resonant circuit 120 in the operating state is driven by the full-bridge driving circuit. Alternatively, when the bridge arm circuit 110 at one end of the resonant circuit 120 in the operating state is connected to the corresponding driving signal, and the bridge arm circuit 110 at the other end is connected to the conduction signal, the resonant circuit 120 in the operating state is driven by the half-bridge driving circuit.

[0045] Understandably, in this embodiment, only one resonant circuit 120 of the electromagnetic heating circuit 10 is in operation. Since each resonant circuit 120 is connected to two ends of a bridge arm circuit 110, when only one resonant circuit 120 is in operation, the bridge arm circuits 110 at both ends of the resonant circuit 120 can form a full-bridge drive circuit; or one of the bridge arm circuits 110 at both ends of the resonant circuit 120 is connected to a drive signal as a half-bridge drive circuit, the other bridge arm circuit 110 is connected to a conduction signal as a conduction branch, and the bridge arm circuits 110 that are not directly connected to the resonant circuit 120 are in a non-operating state.

[0046] For example, when the second resonant circuit 122 is in operation, the second bridge arm circuit 112 and the third bridge arm circuit 113 can constitute a full-bridge drive circuit to drive the second resonant circuit 122. When the second bridge arm circuit 112 acts as a half-bridge drive circuit, the second bridge arm circuit 112 receives the drive signal, and the third bridge arm circuit 113 receives the conduction signal; when the third bridge arm circuit 113 acts as a half-bridge drive circuit, the third bridge arm circuit 113 receives the drive signal, and the second bridge arm circuit 112 receives the conduction signal. See details... Figure 4 , Figure 4 This is a schematic diagram of the driving timing of an embodiment of the electromagnetic heating circuit provided in this application when it is in the fourth operating mode. Each bridge arm circuit 110 includes a first switch M1 and a second switch M2. The control terminal of the first switch M1 in the first bridge arm circuit 111 is S1, and the control terminal of the second switch M2 is S2; the control terminal of the first switch M1 in the second bridge arm circuit 112 is S3, and the control terminal of the second switch M2 is S4; the control terminal of the first switch M1 in the third bridge arm circuit 113 is S5, and the control terminal of the second switch M2 is S6; the control terminal of the first switch M1 in the fourth bridge arm circuit 114 is S7, and the control terminal of the second switch M2 is S8. In this embodiment, the first bridge arm circuit 111 and the fourth bridge arm circuit 114 are always inactive, or in other words, the intermediate output terminals of the first bridge arm circuit 111 and the fourth bridge arm circuit 114 never output. The second bridge arm circuit 112 and the third bridge arm circuit 113 are connected to corresponding driving signals so that the second resonant circuit 122 is driven by the full-bridge driving circuit. The duty cycle of the voltage of the second resonant circuit 122, or the output voltage of the second bridge arm circuit 112 and the third bridge arm circuit 113, is adjusted by the phase difference between the second bridge arm circuit 112 and the third bridge arm circuit 113 (the shift phase of the third bridge arm circuit 113 relative to the second bridge arm circuit 112). In this embodiment, the control terminals of the first switch M1 and the second switch M2 are turned on when receiving a high level and turned off when receiving a low level. In other embodiments, the control terminals of the first switch M1 and the second switch M2 are turned on when receiving a low level and turned off when receiving a high level; this is not a limitation.

[0047] In one embodiment, the electromagnetic heating circuit 10 is configured with a fifth operating mode. When the electromagnetic heating circuit 10 is in the fifth operating mode, any two of the first resonant circuit 121, the second resonant circuit 122, or the third resonant circuit 123 are in operation. When the two resonant circuits 120 are operating, they can be driven by their respective full-bridge drive circuits; or by their respective half-bridge drive circuits; or by both half-bridge and full-bridge drive circuits, so that the electromagnetic heating circuit 10 can adapt to different heating power requirements.

[0048] For example, when two adjacent resonant circuits 120 are in operation, the bridge arm circuits 110 connected to both adjacent resonant circuits 120 serve as shared bridge arm circuits 110. The shared bridge arm circuit 110, and the two bridge arm circuits 110 adjacent to it, are used to receive corresponding drive signals. The two adjacent resonant circuits 120 are driven by corresponding full-bridge drive circuits. For instance, when the first resonant circuit 121 and the second resonant circuit 122 are simultaneously in operation, and the third resonant circuit 123 is in a non-operational state, the first bridge arm circuit 111 and the second bridge arm circuit 112 constitute the full-bridge drive circuit for the first resonant circuit 121. The output voltage frequency and duty cycle of the full-bridge drive circuit for the first resonant circuit 121 are adjustable to adjust the output power of the first resonant circuit 121. The second bridge arm circuit 112 and the third bridge arm circuit 113 constitute the full-bridge drive circuit for the second resonant circuit 122. The output voltage frequency and duty cycle of the full-bridge drive circuit for the second resonant circuit 122 are also adjustable to adjust the output power of the second resonant circuit 122. The second bridge arm circuit 112 serves as a shared bridge arm circuit 110.

[0049] For example, when two adjacent resonant circuits 120 are in operation, the bridge arm circuits 110 connected to both adjacent resonant circuits 120 serve as shared bridge arm circuits 110. The shared bridge arm circuit 110 receives a conduction signal, and when the two bridge arm circuits 110 adjacent to the shared bridge arm circuit 110 receive their corresponding drive signals, the two adjacent resonant circuits 120 are driven by their respective half-bridge drive circuits. For instance, in the shared bridge arm circuit 110, the first switch M1 is always on, the second switch M2 is always off, and the middle output terminal of the shared bridge arm circuit 110 is always connected to the positive terminal of the power supply; or, in the case of a shared bridge arm circuit 110, the second switch M2 is always on, the first switch M1 is always off, and the middle output terminal of the shared bridge arm circuit 110 is always connected to the negative terminal of the power supply. In the case of two resonant circuits 120 each connected to a separate, non-shared bridge arm circuit 110, the first switch M1 and the second switch M2 switch periodically, and the middle output terminal outputs a high-frequency high and low voltage. Each of the bridge arm circuits 110 connected to the resonant circuit 120 and not shared with each other serves as a corresponding half-bridge drive circuit, and each can be freely adjusted without affecting the others. The output voltage frequency and duty cycle of each half-bridge drive circuit can be adjusted separately to regulate the output power of each resonant circuit 120.

[0050] For example, when two adjacent resonant circuits 120 are in operation, the bridge arm circuits 110 connected to both adjacent resonant circuits 120 serve as shared bridge arm circuits 110. One of the two adjacent bridge arm circuits 110 and the shared bridge arm circuit 110 are connected to a corresponding drive signal, and when the other of the two adjacent bridge arm circuits 110 is connected to a conduction signal, one of the resonant circuits 120 is driven by the corresponding half-bridge drive circuit, and the other resonant circuit 120 is driven by the corresponding full-bridge drive circuit. For example, the first resonant circuit 121 is driven by the half-bridge drive circuit, and the second resonant circuit 122 is driven by the full-bridge drive circuit. The first bridge arm circuit 111 is connected to a conduction signal, and the second bridge arm circuit 112 and the third bridge arm circuit 113 are connected to drive signals.

[0051] Specifically, see Figure 5 , Figure 5This is a driving timing diagram of an embodiment of the electromagnetic heating circuit provided in this application when it is in the fifth operating mode. Each bridge arm circuit 110 includes a first switch M1 and a second switch M2. The control terminal of the first switch M1 in the first bridge arm circuit 111 is S1, and the control terminal of the second switch M2 is S2; the control terminal of the first switch M1 in the second bridge arm circuit 112 is S3, and the control terminal of the second switch M2 is S4; the control terminal of the first switch M1 in the third bridge arm circuit 113 is S5, and the control terminal of the second switch M2 is S6; the control terminal of the first switch M1 in the fourth bridge arm circuit 114 is S7, and the control terminal of the second switch M2 is S8. In this embodiment, the fourth bridge arm circuit 114 is always inactive, or in other words, the intermediate output terminal of the fourth bridge arm circuit 114 never outputs. The first bridge arm circuit 111, the second bridge arm circuit 112, and the third bridge arm circuit 113 are connected to corresponding drive signals, so that the first resonant circuit 121 is driven by the full-bridge drive circuit composed of the first bridge arm circuit 111 and the second bridge arm circuit 112; and the second resonant circuit 122 is driven by the full-bridge drive circuit composed of the second bridge arm circuit 112 and the third bridge arm circuit 113. The duty cycle of the voltage of the first resonant circuit 121, or the output voltage of the first bridge arm circuit 111 and the second bridge arm circuit 112, is adjusted by the phase difference between the first bridge arm circuit 111 and the second bridge arm circuit 112 (the shifting phase of the second bridge arm circuit 112 relative to the first bridge arm circuit 111); the duty cycle of the voltage of the second resonant circuit 122, or the output voltage of the second bridge arm circuit 112 and the third bridge arm circuit 113, is adjusted by the phase difference between the second bridge arm circuit 112 and the third bridge arm circuit 113 (the shifting phase of the third bridge arm circuit 113 relative to the second bridge arm circuit 112). In this embodiment, the control terminals of the first switch M1 and the second switch M2 are turned on when they receive a high level and turned off when they receive a low level. In other embodiments, the control terminals of the first switch M1 and the second switch M2 are turned on when they receive a low level and turned off when they receive a high level; this is not a limitation.

[0052] In one embodiment, the electromagnetic heating circuit 10 is configured with a sixth operating mode. When the electromagnetic heating circuit 10 is in the sixth operating mode, the first resonant circuit 121 and the third resonant circuit 123 are in operation. In this mode, the second bridge arm circuit 112 and the third bridge arm circuit 113 are connected to the same conduction signal, and the first bridge arm circuit 111 and the fourth bridge arm circuit 114 are connected to corresponding drive signals. Alternatively, the second bridge arm circuit 112 and the third bridge arm circuit 113 are connected to the same drive signal, and the first bridge arm circuit 111 and the fourth bridge arm circuit 114 are connected to corresponding drive signals.

[0053] Understandably, when the first resonant circuit 121 and the third resonant circuit 123 are both in operation, and the second resonant circuit 122 is in a non-operating state, the voltages across the second resonant circuit 122 are the same, or the voltage difference between the two ends of the second resonant circuit 122 is zero. At this time, the second bridge arm circuit 112 and the third bridge arm circuit 113 need to maintain synchronous operation. In this embodiment, when the electromagnetic heating circuit 10 is in the sixth operating mode, the first resonant circuit 121 and the third resonant circuit 123 can be simultaneously driven by the corresponding full-bridge drive circuit; or driven by the corresponding half-bridge drive circuit; or the first resonant circuit 121 can be driven by the corresponding half-bridge drive circuit, and the third resonant circuit 123 can be driven by the corresponding full-bridge drive circuit; or the third resonant circuit 123 can be driven by the corresponding half-bridge drive circuit, and the first resonant circuit 121 can be driven by the corresponding full-bridge drive circuit. This is not limited to any particular mode. It is worth noting that when the electromagnetic heating circuit 10 is in the sixth working mode, the second bridge arm circuit 112 and the third bridge arm circuit 113 need to work synchronously. That is, the second bridge arm circuit 112 and the third bridge arm circuit 113 are simultaneously connected to the same conduction signal or the same drive signal.

[0054] For example, the first resonant circuit 121 and the third resonant circuit 123 are driven by corresponding half-bridge drive circuits, the first bridge arm circuit 111 and the fourth bridge arm circuit 114 are connected to corresponding drive signals, and the second bridge arm circuit 112 and the third bridge arm circuit 113 are simultaneously connected to the same on signal. Alternatively, the first resonant circuit 121 and the third resonant circuit 123 are driven by corresponding full-bridge drive circuits, the first bridge arm circuit 111 and the fourth bridge arm circuit 114 are connected to corresponding drive signals, and the second bridge arm circuit 112 and the third bridge arm circuit 113 are simultaneously connected to the same drive signal. Or, the first resonant circuit 121 is driven by a half-bridge drive circuit, the third resonant circuit 123 is driven by a full-bridge drive circuit, the first bridge arm circuit 111 is connected to an on signal, the fourth bridge arm circuit 114 is connected to a corresponding drive signal, and the second bridge arm circuit 112 and the third bridge arm circuit 113 are simultaneously connected to the same drive signal.

[0055] This application provides a heating device (not shown), which includes multiple heating zones (not shown) and an electromagnetic heating circuit according to any of the above embodiments. The heating device includes multiple heating zones, each of which includes one or more coils of a resonant circuit. The heating device can be a rice cooker using electromagnetic induction heating, an induction cooker, or other heating devices, and is not limited thereto.

[0056] The above are merely embodiments of this application and do not limit the patent scope of this application. Any equivalent structural or procedural transformations made using the content of this application's specification and drawings, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of this application.

Claims

1. An electromagnetic heating circuit, characterized in that, The electromagnetic heating circuit includes: N resonant circuits; (N+1) bridge arm circuits are arranged in parallel and interleaved with the N resonant circuits. The two ends of each resonant circuit are respectively connected to the middle output terminals of the two adjacent bridge arm circuits, and the first resonant circuit is not connected to the (N+1)th resonant circuit. Wherein, N is greater than or equal to 3.

2. The electromagnetic heating circuit according to claim 1, characterized in that, The (N+1) bridge arm circuits include at least a first bridge arm circuit, a second bridge arm circuit, a third bridge arm circuit, and a fourth bridge arm circuit arranged in parallel. The N resonant circuits include at least a first resonant circuit, a second resonant circuit, and a third resonant circuit. The first resonant circuit is connected in series between the intermediate output terminals of the first bridge arm circuit and the second bridge arm circuit; the second resonant circuit is connected in series between the intermediate output terminals of the second bridge arm circuit and the third bridge arm circuit; and the third resonant circuit is connected in series between the intermediate output terminals of the third bridge arm circuit and the fourth bridge arm circuit.

3. The electromagnetic heating circuit according to claim 2, characterized in that, The electromagnetic heating circuit is configured with a first operating mode. When the electromagnetic heating circuit is in the first operating mode, the first resonant circuit, the second resonant circuit, and the third resonant circuit are all in operation simultaneously. The first resonant circuit and the second resonant circuit share the second bridge arm circuit, and the second resonant circuit and the third resonant circuit share the third bridge arm circuit. Thus, the first resonant circuit, the second resonant circuit, and the third resonant circuit are driven by the corresponding full-bridge drive circuit. When the first bridge arm circuit, the fourth bridge arm circuit, and the shared bridge arm circuit are connected to the corresponding drive signal, they drive the corresponding resonant circuit to operate.

4. The electromagnetic heating circuit according to claim 2, characterized in that, The electromagnetic heating circuit is configured with a second operating mode. When the electromagnetic heating circuit is in the second operating mode, the first resonant circuit, the second resonant circuit, and the third resonant circuit are all in operation at the same time. Two non-adjacent bridge arm circuits are used as shared bridge arm circuits, so that the first resonant circuit, the second resonant circuit, and the third resonant circuit are driven by the corresponding half-bridge drive circuits. When the shared bridge arm circuit is connected to a conduction signal, and the non-shared bridge arm circuit is connected to the corresponding drive signal, the corresponding resonant circuit is driven to work.

5. The electromagnetic heating circuit according to claim 2, characterized in that, The electromagnetic heating circuit is configured with a third operating mode. When the electromagnetic heating circuit is in the third operating mode, the first resonant circuit, the second resonant circuit, and the third resonant circuit are all in operation simultaneously, and any one of the middle bridge arm circuits serves as a shared bridge arm circuit. This allows the first bridge arm circuit, the second bridge arm circuit, the third bridge arm circuit, and the fourth bridge arm circuit to form two half-bridge drive circuits and one full-bridge drive circuit. Thus, two of the resonant circuits are driven by their corresponding half-bridge drive circuits, and the remaining resonant circuit is driven by its corresponding full-bridge drive circuit. The shared bridge arm circuit is connected to a conduction signal, and the non-shared bridge arm circuit is connected to its corresponding drive signal.

6. The electromagnetic heating circuit according to claim 2, characterized in that, The electromagnetic heating circuit is configured with a fourth working mode. When the electromagnetic heating circuit is in the fourth working mode, any one of the first resonant circuit, the second resonant circuit, or the third resonant circuit is in working state. In this configuration, the bridge arm circuits at both ends of the resonant circuit in the working state are connected to corresponding drive signals, and the resonant circuit in the working state is driven by a full-bridge drive circuit; or When the resonant circuit is in operation, one end of its bridge arm circuit is connected to a corresponding driving signal, and the other end of its bridge arm circuit is connected to a conduction signal. The resonant circuit in operation is driven by a half-bridge driving circuit.

7. The electromagnetic heating circuit according to claim 2, characterized in that, The electromagnetic heating circuit is configured with a fifth working mode. When the electromagnetic heating circuit is in the fifth working mode, any two of the first resonant circuit, the second resonant circuit, or the third resonant circuit are in working state. When two adjacent resonant circuits are in operation, the bridge arm circuits connected to both adjacent resonant circuits serve as shared bridge arm circuits. The shared bridge arm circuit and the two bridge arm circuits adjacent to the shared bridge arm circuit are connected to corresponding drive signals, and the two adjacent resonant circuits are driven by corresponding full-bridge drive circuits; or When two adjacent resonant circuits are in operation, the bridge arm circuits connected to both adjacent resonant circuits serve as shared bridge arm circuits. The shared bridge arm circuits are connected to a conduction signal, and the two bridge arm circuits adjacent to the shared bridge arm circuits are connected to corresponding drive signals. The two adjacent resonant circuits are driven by corresponding half-bridge drive circuits; or When two adjacent resonant circuits are in operation, the bridge arm circuits connected to both adjacent resonant circuits are used as shared bridge arm circuits. One of the two adjacent bridge arm circuits of the shared bridge arm circuit and the shared bridge arm circuit are connected to the corresponding drive signal, and the other of the two adjacent bridge arm circuits of the shared bridge arm circuit are connected to the conduction signal. One of the resonant circuits is driven by the corresponding half-bridge drive circuit, and the other resonant circuit is driven by the corresponding full-bridge drive circuit.

8. The electromagnetic heating circuit according to claim 7, characterized in that, The electromagnetic heating circuit is configured with a sixth working mode. When the electromagnetic heating circuit is in the sixth working mode, the first resonant circuit and the third resonant circuit are in working state. Wherein, the second bridge arm circuit and the third bridge arm circuit are used to receive the same conduction signal, and the first bridge arm circuit and the fourth bridge arm circuit are used to receive corresponding drive signals; or The second bridge arm circuit and the third bridge arm circuit are used to receive the same drive signal, and the first bridge arm circuit and the fourth bridge arm circuit are used to receive the corresponding drive signal.

9. The electromagnetic heating circuit according to claim 1, characterized in that, The bridge arm circuit includes: The first switching transistor has a first terminal connected to a positive power supply voltage, a control terminal connected to a control signal, and a second terminal serving as the intermediate output terminal. The second switch has its first end connected to the second end of the first switch, its control terminal connected to the control signal, and its second end grounded.

10. A heating device, characterized in that, The heating device includes: The electromagnetic heating circuit according to any one of claims 1-8, wherein the heating device includes a plurality of heating zones, each of the heating zones including one or more coils of the resonant circuit.

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