Parallel resonant induction cooker control circuit, PCB board and induction cooker

Abstract

The application relates to the technical field of electromagnetic induction heating, and discloses a parallel resonant type induction cooker control circuit, a PCB (Printed Circuit Board) and an induction cooker. The control circuit is cooperatively matched by an input processing unit, an auxiliary power generation unit, a SiC isolation driving unit, a parallel resonant inverter unit and a master control unit, so that a low-voltage direct-current induction heating control architecture suitable for a non-mains power supply scene is built. The parallel resonant inverter unit can realize zero-voltage soft switching, and greatly reduce switching loss and electromagnetic interference. The auxiliary power generation unit provides multiple stable and isolated power supplies, and guarantees the independent and stable work of the control unit, the driving unit and the inverter unit. The master control unit realizes frequency closed-loop locking through resonant state feedback, so that the working frequency is matched with the resonant frequency. The overall circuit has high integration and simple structure, solves the problems of low efficiency, poor reliability, unmatched driving and devices of a traditional low-voltage induction cooker, and significantly improves the energy conversion efficiency, operation stability and scene adaptation capability of the whole machine.

Description

Technical Field

[0001] This invention relates to the field of electromagnetic induction heating technology, and in particular to a parallel resonant induction cooker control circuit, PCB board, and induction cooker. Background Technology

[0002] With the increasing popularity of non-mains power scenarios such as in-vehicle travel, outdoor camping, and energy storage power supply, induction cookers adapted to low-voltage DC power supply have become an important research and development direction in the industry. Among them, the 48VDC low-voltage input technology solution has become the mainstream choice in the field of low-voltage high-power induction heating due to its high power adaptability and excellent safety level.

[0003] Existing low-voltage high-power induction cooker technologies mostly adopt a full-bridge inverter topology architecture. By abandoning the traditional boost circuit to reduce system complexity, conventional power devices and basic isolation drive are used to achieve power output, and a series resonant circuit is used to complete induction heating. To a certain extent, this breaks through the technical limitations of traditional low-voltage induction cookers, which have low power and bulky size, and lays the foundation for low-voltage DC heating technology.

[0004] However, from the perspective of the current technological level in the industry, this type of low-pressure, high-power induction heating solution still has common technical shortcomings, making it difficult to meet the technical requirements of high frequency, high efficiency, and high reliability in practical applications. Specifically, these shortcomings are as follows: First, when using conventional optocoupler isolation drive, there are technical defects such as slow switching response speed and insufficient high-frequency driving capability. Moreover, under high-frequency operating conditions, it is easy to cause a surge in switching losses and serious heat generation of devices, which seriously restricts the improvement of the overall energy conversion efficiency. Secondly, it is difficult to achieve zero-voltage soft switching using a series resonant structure. Under the low-voltage, high-current operating condition of 48VDC, the switching losses and electromagnetic interference are significant, making it difficult for the heating system to achieve the ideal energy efficiency ratio and power density.

[0005] It is evident that existing technologies still need improvement and enhancement. Summary of the Invention

[0006] In view of the shortcomings of the prior art, the purpose of this invention is to provide a parallel resonant induction cooker control circuit, which has the advantages of high integration and simple structure, and solves the problems of low efficiency, poor reliability and mismatch between drive and device in traditional low-voltage induction cookers.

[0007] To achieve the above objectives, the present invention adopts the following technical solution: A parallel resonant induction cooker control circuit includes an input processing unit, an auxiliary power generation unit, a SiC isolation drive unit, a parallel resonant inverter unit, and a main control unit. The input terminal of the input processing unit is connected to a 48V DC power supply. The output terminal of the input processing unit is connected to the input terminal of the auxiliary power generation unit and the main power supply terminal of the parallel resonant inverter unit. The output terminal of the auxiliary power generation unit is connected to the power supply terminal of the SiC isolation drive unit, the control power supply terminal of the parallel resonant inverter unit, and the power supply terminal of the main control unit. The output terminal of the main control unit is connected to the input terminal of the SiC isolation drive unit, and the output terminal of the SiC isolation drive unit is connected to the control input terminal of the parallel resonant inverter unit. The power output terminal of the parallel resonant inverter unit is connected to the electromagnetic heating coil, and the feedback terminal of the parallel resonant inverter unit is connected to the resonant state feedback terminal of the main control unit.

[0008] The parallel resonant induction cooker control circuit further includes a temperature sampling unit and a fan drive unit; the input terminal of the temperature sampling unit is used to connect to a thermistor, and the output terminal of the temperature sampling unit is connected to the overheat detection terminal of the main control unit; the input terminal of the fan drive unit is connected to the first PWM output terminal of the main control unit, and the output terminal of the fan drive unit is used to connect to a cooling fan.

[0009] In the parallel resonant induction cooker control circuit, the main control unit includes a first control chip U1, a communication unit, and a programming unit. The VDD and VCC pins of the first control chip U1 are connected to the output of the auxiliary power generation unit, the PPGH pin of the first control chip U1 is connected to the input of the SiC isolated drive unit, and the SYS-, SYS+, OPIN, OPOUT, and I / SUR pins of the first control chip U1 are connected to the feedback of the parallel resonant inverter unit. The communication unit is connected to the TXD and RXD pins of the first control chip U1, and the programming unit is connected to the ICPDA and ICPCK pins of the first control chip U1.

[0010] In the parallel resonant induction cooker control circuit, the auxiliary power generation unit includes a first voltage conversion unit, a second voltage conversion unit, and a third voltage conversion unit. The input terminal of the first voltage conversion unit is connected to the output terminal of the input processing unit, and the output terminal of the first voltage conversion unit is connected to the input terminals of the second and third voltage conversion units and the VCC pin of the first control chip U1, respectively, for outputting an 18V DC voltage. The output terminal of the second voltage conversion unit is connected to the VDD pin of the first control chip U1, the power supply terminal of the communication unit, the power supply terminal of the programming unit, and the first power supply terminal of the SiC isolation drive unit, respectively, for outputting a 5V DC voltage. The output terminal of the third voltage conversion unit is connected to the second power supply terminal of the SiC isolation drive unit, for outputting an 18V B voltage and a -4V voltage.

[0011] In the parallel resonant induction cooker control circuit, the SiC isolated drive unit includes a second control chip U2, a drive unit, and a gate adapter unit. The input terminal of the drive unit is connected to the pin PPGH of the first control chip U1, and the output terminal of the drive unit is connected to the pin IN+ of the second control chip U2. The pins OUTH and OUTL of the second control chip U2 are connected to the input terminal of the gate adapter unit, and the output terminal of the gate adapter unit is connected to the control input terminal of the parallel resonant inverter unit.

[0012] In the parallel resonant induction cooker control circuit, the parallel resonant inverter unit includes a switching section and a parallel resonant section; the output terminal of the gate adapter is connected to the gate terminal of the switching section, the drain terminal of the switching section is connected to the parallel resonant section, and the source terminal of the switching section is grounded; the power output terminal of the parallel resonant section is used to connect to the electromagnetic heating coil, and the feedback terminal of the parallel resonant section is connected to the pins SYS-, SYS+, OPIN, OPOUT, and I / SUR of the first control chip U1, respectively.

[0013] In the parallel resonant induction cooker control circuit, the switching section includes a first field-effect transistor (MOSFET) MOS1, which is a SiC MOSFET; the parallel resonant section includes a filter group, a voltage sampling group, a current sampling group, and a resonant capacitor group; the gate of the first MOSFET MOS1 is connected to the output terminal of the gate adapter, the drain of the first MOSFET MOS1 is connected to the other end of the resonant capacitor group, and the source of the first MOSFET MOS1 is grounded; the pin OUT of the resonant capacitor group is used to connect to the electromagnetic heating coil to form a resonant circuit; one end of the filter group is connected to the output terminal of the input processing unit and the input terminal of the current sampling group, and the other end of the filter group is connected to one end of the resonant capacitor group; the input terminal of the voltage sampling group is connected to the resonant circuit, the output terminal of the voltage sampling group is connected to the pins SYS- and SYS+ of the first control chip U1, and the output terminal of the current sampling group is connected to the pins OPPIN, OPOUT, and I / SUR of the first control chip U1.

[0014] In the parallel resonant induction cooker control circuit, the input processing unit includes an input section, a filtering section, and a reverse connection protection section. The input terminal of the input section is connected to a 48V DC power supply, and the output terminal of the input section is connected to the input terminal of the reverse connection protection section, which is used to determine the input polarity. The input terminal of the filtering section is connected to a 48V DC power supply in parallel, and the output terminal of the filtering section is connected to the input terminal of the auxiliary power generation unit and the main power supply terminal of the parallel resonant inverter unit, respectively.

[0015] The present invention also provides a PCB board on which the parallel resonant induction cooker control circuit as described above is printed.

[0016] The present invention also provides an induction cooker, wherein the induction cooker uses a parallel resonant induction cooker control circuit as described above for operation control.

[0017] Beneficial effects: This invention provides a parallel resonant induction cooker control circuit. Using 48VDC as the input power, it establishes a low-voltage DC induction heating control architecture suitable for non-mains power scenarios such as vehicle-mounted, outdoor, and energy storage environments through the coordinated operation of an input processing unit, an auxiliary power generation unit, a SiC isolated drive unit, a parallel resonant inverter unit, and a main control unit. The parallel resonant inverter unit achieves zero-voltage soft switching, significantly reducing switching losses and electromagnetic interference. The auxiliary power generation unit provides multiple stable isolated power supplies, ensuring independent and stable operation of the control, drive, and inverter units. The main control unit achieves frequency closed-loop locking through resonant state feedback, matching the operating frequency with the resonant frequency. The overall circuit has high integration and a simple structure, solving the problems of low efficiency, poor reliability, and mismatch between drive and components in traditional low-voltage induction cookers. It significantly improves the overall energy conversion efficiency, operational stability, and scenario adaptability of the machine, while reducing circuit layout complexity and manufacturing costs. Attached Figure Description

[0018] Figure 1 A circuit block diagram of the control circuit provided by the present invention; Figure 2 The circuit schematic diagram of the input processing unit, SiC isolation driving unit and parallel resonant inverter unit provided by the present invention; Figure 3 The circuit schematic diagrams of the main control unit, temperature sampling unit, and fan drive unit provided for this invention; Figure 4 The circuit diagram of the auxiliary power generation unit provided by the present invention.

[0019] Explanation of key component symbols: 1-Input processing unit, 11-Input section, 12-Filtering section, 13-Reverse connection protection section, 2-Auxiliary power generation unit, 21-First voltage conversion section, 22-Second voltage conversion section, 23-Third voltage conversion section, 3-SiC isolation drive unit, 31-Drive section, 32-Gate adapter section, 4-Parallel resonant inverter unit, 41-Switch section, 42-Parallel resonant section, 5-Main control unit, 51-Communication section, 52-Programming section, 61-Temperature sampling unit, 62-Fan drive unit. Detailed Implementation

[0020] This invention provides a parallel resonant induction cooker control circuit, a PCB board, and an induction cooker. To make the objectives, technical solutions, and effects of this invention clearer and more explicit, the invention will be further described in detail below with reference to the accompanying drawings and embodiments.

[0021] In the description of this invention, it should be understood that the terms "installation" and "connection" should be interpreted broadly, and those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances; in addition, components marked as NC in the drawings indicate that they are not installed in this embodiment.

[0022] Please see Figures 1 to 4 This invention provides a parallel resonant induction cooker control circuit, including an input processing unit 1, an auxiliary power generation unit 2, a SiC isolation drive unit 3, a parallel resonant inverter unit 4, and a main control unit 5. The input terminal of the input processing unit 1 is connected to a 48V DC power supply, and the output terminal of the input processing unit 1 is connected to the input terminal of the auxiliary power generation unit 2 and the main power supply terminal of the parallel resonant inverter unit 4. The output terminal of the auxiliary power generation unit 2 is connected to the power supply terminal of the SiC isolation drive unit 3, the control power supply terminal of the parallel resonant inverter unit 4, and the power supply terminal of the main control unit 5. The output terminal of the main control unit 5 is connected to the input terminal of the SiC isolation drive unit 3, and the output terminal of the SiC isolation drive unit 3 is connected to the control input terminal of the parallel resonant inverter unit 4. The power output terminal of the parallel resonant inverter unit 4 is connected to the electromagnetic heating coil, and the feedback terminal of the parallel resonant inverter unit 4 is connected to the resonant state feedback terminal of the main control unit 5.

[0023] This invention discloses a parallel resonant induction cooker control circuit. Using 48VDC as the input power, it establishes a low-voltage DC induction heating control architecture suitable for non-mains power scenarios such as vehicle-mounted, outdoor, and energy storage environments through the coordinated operation of an input processing unit 1, an auxiliary power generation unit 2, a SiC isolated drive unit 3, a parallel resonant inverter unit 4, and a main control unit 5. The parallel resonant inverter unit 4 enables zero-voltage soft switching, significantly reducing switching losses and electromagnetic interference. The auxiliary power generation unit 2 provides multiple stable isolated power supplies, ensuring independent and stable operation of the control, drive, and inverter units. The main control unit 5 achieves frequency closed-loop locking through resonant state feedback, matching the operating frequency with the resonant frequency. The overall circuit exhibits high integration and a simple structure, solving the problems of low efficiency, poor reliability, and mismatch between drive and components in traditional low-voltage induction cookers. It significantly improves the overall energy conversion efficiency, operational stability, and scenario adaptability of the machine, while reducing circuit layout complexity and manufacturing costs.

[0024] In this embodiment, the input terminal of the input processing unit 1 is connected to a 48VDC power supply for reverse connection protection, surge suppression, and ripple filtering of the input 48VDC power. The processed power is then supplied to the input terminal of the auxiliary power generation unit 2 and the main power supply terminal of the parallel resonant inverter unit 4. The auxiliary power generation unit 2 uses a multi-stage voltage conversion chip to convert 48VDC into multiple voltages of 18V+, 5V+, 18VB+, and -4V. The output voltages supply the control power supply terminals of the SiC isolated drive unit 3, the parallel resonant inverter unit 4, and the main control unit 5, respectively. The main control unit 5 uses a [model missing] The first control chip U1 is HT45F0036, which outputs a PWM control signal to the input terminal of SiC isolated drive unit 3. The second control chip U2, model 1ED3142MU12F, is used in SiC isolated drive unit 3. It isolates and amplifies the main control signal and sends it to the control input terminal of parallel resonant inverter unit 4. Parallel resonant inverter unit 4 is composed of SiC power transistors and resonant elements. Under the control of the drive signal, it completes high-frequency inversion and parallel resonance. Its power output terminal is connected to the electromagnetic heating coil to realize heating output. Its feedback terminal feeds back the resonant state signal to the resonant state feedback terminal of the main control unit 5.

[0025] Further, please refer to Figure 1 and Figure 3 The control circuit further includes a temperature sampling unit 61 and a fan drive unit 62; the input terminal of the temperature sampling unit 61 is used to connect to a thermistor, and the output terminal of the temperature sampling unit 61 is connected to the overheat detection terminal of the main control unit 5; the input terminal of the fan drive unit 62 is connected to the first PWM output terminal of the main control unit 5, and the output terminal of the fan drive unit 62 is used to connect to a cooling fan.

[0026] In this embodiment, the temperature sampling unit 61 includes a pot bottom temperature sampling branch and a SiC power transistor temperature sampling branch to achieve dual-point temperature monitoring. The pot bottom temperature sampling branch includes a 52nd resistor R52, a 50th resistor R50, and a 17th capacitor C17. One end of the 52nd resistor R52 and one end of the 17th capacitor C17 are respectively used to connect to the pot bottom NTC thermistor. The pot bottom temperature is collected in real time by the branch to sense the working temperature of the bottom of the pot and fed back to the NTC1 pin of the first control chip U1. The SiC power transistor temperature sampling branch includes a thermistor RT1, a 37th resistor R37, and a 34th capacitor C17. Resistor R34 and capacitor C10, along with thermistor RT1, are attached to the first field-effect transistor MOS1 to collect the operating temperature of the SiC power transistor in real time and feed it back to pin TMOS1 of the first control chip U1. After voltage division and filtering, the two temperature sampling signals are connected to the overheat detection terminal of the main control unit 5. When either sampling temperature exceeds the preset threshold, the main control unit 5 triggers overheat protection, reducing the heating power or directly shutting off the power output. By synchronously monitoring the bottom of the pot and the core heating area of ​​the power transistor, the monitoring blind spot of a single sampling point is eliminated, effectively avoiding dry burning of the pot and overheating damage to the SiC power transistor, improving the safety of the whole machine and extending the service life of the devices.

[0027] The fan drive unit 62 includes a MOS2 power transistor and a cooling fan FAN. Its input terminal is connected to the first PWM output terminal of the first control chip U1. The main control unit 5 outputs a PWM signal with a corresponding duty cycle according to the temperature sampling signal to control the conduction degree of MOS2, thereby adjusting the speed of the cooling fan to achieve intelligent temperature control and heat dissipation, reducing fan power consumption and noise while ensuring heat dissipation effect.

[0028] Further, please refer to Figure 1 and Figure 3 The main control unit 5 includes a first control chip U1, a communication unit 51, and a programming unit 52. The VDD and VCC pins of the first control chip U1 are respectively connected to the output terminal of the auxiliary power generation unit 2. The PPGH pin of the first control chip U1 is connected to the input terminal of the SiC isolated drive unit 3. The SYS-, SYS+, OPIN, OPOUT, and I / SUR pins of the first control chip U1 are respectively connected to the feedback terminal of the parallel resonant inverter unit 4. The communication unit 51 is connected to the TXD and RXD pins of the first control chip U1. The programming unit 52 is connected to the ICPDA and ICPCK pins of the first control chip U1.

[0029] In this embodiment, the main control unit 5 includes a first control chip U1 (model HT45F0036), a communication unit 51, and a programming unit 52. The first control chip U1's pins VDD and VCC are respectively connected to the 5V+ and 18V+ voltages output by the auxiliary power generation unit 2 to obtain a stable power supply. The first control chip U1's pin PPGH outputs a high-frequency PWM drive signal to the input terminal of the SiC isolated drive unit 3. Pins SYS- and SYS+ receive the resonant voltage signal fed back from the parallel resonant inverter unit 4. Pins OPIN and OP... The OUT pin receives the resonant current signal fed back from the parallel resonant inverter unit 4, and the I / SUR pin is used to determine whether overcurrent protection is triggered. The communication unit 51 consists of a serial port level matching resistor and an interface, and is connected to the TXD and RXD pins of the first control chip U1 to realize data interaction between the main control unit 5 and the operation panel and the host computer, and to transmit power settings, working status and fault information. The programming unit 52 is connected to the ICPDA and ICPCK pins of the first control chip U1, and is used for programming, debugging and firmware updates of the chip control program, enhancing the applicability and maintainability of the circuit.

[0030] Further, please refer to Figure 1 and Figure 4 The auxiliary power generation unit 2 includes a first voltage conversion unit 21, a second voltage conversion unit 22, and a third voltage conversion unit 23. The input terminal of the first voltage conversion unit 21 is connected to the output terminal of the input processing unit 1, and the output terminal of the first voltage conversion unit 21 is connected to the input terminals of the second voltage conversion unit 22, the third voltage conversion unit 23, and the VCC pin of the first control chip U1, respectively, for outputting an 18V DC voltage. The output terminal of the second voltage conversion unit 22 is connected to the VDD pin of the first control chip U1, the power supply terminal of the communication unit 51, the power supply terminal of the programming unit 52, and the first power supply terminal of the SiC isolation driving unit 3, respectively, for outputting a 5V DC voltage. The output terminal of the third voltage conversion unit 23 is connected to the second power supply terminal of the SiC isolation driving unit 3, for outputting an 18V B voltage and a -4V voltage.

[0031] In this embodiment, it is used to convert 48V DC voltage into a stable low-voltage power supply for multiplexed adapter circuits. The first voltage conversion unit 21 uses a switching power supply chip U6 of model LM5164-Q1 as its core. Its input terminal is connected to the 48V DC voltage output from the input processing unit 1. Through switching conversion, it transforms the 48V DC voltage into a stable 18V DC voltage output. The first voltage conversion unit 21 also includes a voltage surge protection group and a voltage detection group. The voltage surge protection group includes a third diode D3, a sixth diode D6, a first resistor R1, a twenty-ninth resistor R29, a twenty-eighth resistor R28, a twenty-seventh resistor R27, a thirtieth resistor R30, a forty-ninth resistor R49, a ninth capacitor C9, and a twenty-eighth capacitor C28. This voltage surge protection group is used to distribute the bus voltage. After clamping, the SUR signal is output and connected to the SUR pin of the main control unit 5 to realize surge overvoltage detection. The voltage detection group includes the 23rd resistor R23, the 35th resistor R35, the 42nd resistor R42, the 46th resistor R46, the 39th resistor R39, and the 21st capacitor C21. The voltage detection group is used to perform high-precision sampling of the 48V bus voltage and outputs a V / AD signal connected to the V / AD pin of the main control unit 5 to realize bus undervoltage and overvoltage status monitoring. The 18V output terminal of the first voltage conversion unit 21 is connected to the input terminal of the second voltage conversion unit 22, the input terminal of the third voltage conversion unit 23, and the VCC pin of the first control chip U1 in the main control unit 5. The second voltage conversion unit 22 is based on a switching power supply chip U5 and a linear regulator U4. The switching power supply chip U5 is model AP2900 and the linear regulator U4 is model AC1117-5.0. It first converts the 18V voltage output from the first voltage conversion unit 21 into a 7.5V intermediate voltage, and then outputs a clean 5V DC voltage after linear regulation. The 5V output terminal is connected to the VDD pin of the first control chip U1, the power supply terminal of the communication unit 51, the power supply terminal of the programming unit 52, and the first power supply terminal of the SiC isolation drive unit 3, respectively, to provide a stable power supply for the control side circuit. The third voltage conversion unit 23 is based on the auxiliary power chip U3 and the auxiliary transformer T1. The auxiliary power chip U3 is model 2EP130R, which converts the input voltage into isolated 18VB and -4V voltage outputs. The 18VB and -4V output terminals are connected to the second power supply terminal of the SiC isolated drive unit 3 to meet the positive and negative drive power supply requirements of the SiC isolated drive chip. The three-stage voltage conversion enables multi-channel isolated and regulated output, ensuring the purity and stability of the output voltage. It can match the power supply voltage requirements of different units such as main control, drive, and inverter, avoiding device damage caused by voltage mismatch. The combination of switching power supply and linear regulation balances voltage conversion efficiency and output ripple control. The integrated surge protection and voltage detection unit eliminates the need for additional detection circuits, simplifying the overall architecture. Multiple independent power supplies can effectively block power interference between modules, improving the system's anti-interference capability and electrical safety level.

[0032] Further, please refer to Figure 1 and Figure 2 The SiC isolated drive unit 3 includes a second control chip U2, a drive unit 31, and a gate adapter unit 32. The input terminal of the drive unit 31 is connected to the pin PPGH of the first control chip U1, and the output terminal of the drive unit 31 is connected to the pin IN+ of the second control chip U2. The pins OUTH and OUTL of the second control chip U2 are connected to the input terminal of the gate adapter unit 32, and the output terminal of the gate adapter unit 32 is connected to the control input terminal of the parallel resonant inverter unit 4.

[0033] In this embodiment, the second control chip U2 is model 1ED3142MU12F, which is a dedicated isolation driver chip for SiC power transistors and can effectively match the high-frequency switching characteristics of SiC power transistors. The driving unit 31 includes a first transistor Q1, a second transistor Q2, a current-limiting resistor RD5, a fifty-eighth resistor R58, a sixty-seventh resistor R67, a sixty-eighth resistor R68, a seventy-first resistor R71, a sixty-sixth resistor R66, an eleventh resistor R11, a thirtieth capacitor C30, and a forty-first capacitor C41. The input terminal of the driving unit 31 is connected to the PPGH pin of the first control chip U1, receives the PWM control signal, and performs push-pull power amplification on the signal to enhance the driving capability. The amplified signal is output to the IN+ pin of the second control chip U2. The second control chip U2 has a built-in electrical isolation module to achieve electrical isolation between the control side and the power side, blocking power circuit interference from entering the main control unit 5; its pins OUTH and OUTL are drive output terminals, which are connected to the input terminals of the gate adapter 32 to output isolated drive signals, ensuring the safe operation of the main control unit 5; The gate adapter 32 includes a seventeenth resistor R17, an eighth resistor R8, a fourth resistor R4, a twenty-first resistor R21, and a drive ground SSGND. Each resistor is a current-limiting resistor used to suppress gate current spikes. The output terminal of the gate adapter 32 is connected to the control input terminal of the parallel resonant inverter unit 4, providing an adapted drive signal for the switching unit 41. In addition, the second control chip U2 has a built-in undervoltage lockout function, which works with the gate adapter 32 to automatically shut down the output when the power supply voltage is insufficient, protecting the power devices and avoiding the problem of increased losses caused by the power transistor not being fully turned on under low drive voltage, thereby improving the reliability of system operation.

[0034] Further, please refer to Figure 1 and Figure 2 The parallel resonant inverter unit 4 includes a switching section 41 and a parallel resonant section 42; the output terminal of the gate adapter 32 is connected to the gate terminal of the switching section 41, the drain terminal of the switching section 41 is connected to the parallel resonant section 42, and the source terminal of the switching section 41 is grounded; the power output terminal of the parallel resonant section 42 is used to connect to the electromagnetic heating coil, and the feedback terminal of the parallel resonant section 42 is connected to the pins SYS-, SYS+, OPIN, OPOUT, and I / SUR of the first control chip U1, respectively.

[0035] Further, please refer to Figure 1 and Figure 2 The switching unit 41 includes a first field-effect transistor (MOSFET) 41, and the parallel resonant unit 42 includes a filter group, a voltage sampling group, a current sampling group, and a resonant capacitor group. The gate of the first MOSFET 41 is connected to the output terminal of the gate adapter, the drain of the first MOSFET 41 is connected to the other end of the resonant capacitor group, and the source of the first MOSFET 41 is grounded. The pin OUT of the resonant capacitor group is used to connect to the electromagnetic heating coil to form a resonant circuit. One end of the filter group is connected to the output terminal of the input processing unit and the input terminal of the current sampling group, and the other end of the filter group is connected to one end of the resonant capacitor group. The input terminal of the voltage sampling group is connected to the resonant circuit, the output terminal of the voltage sampling group is connected to the pins SYS- and SYS+ of the first control chip U1, and the output terminal of the current sampling group is connected to the pins OPPIN, OPOUT, and I / SUR of the first control chip U1.

[0036] In this embodiment, the switching unit 41 includes a first field-effect transistor MOS1, which is a SiC MOSFET. Its gate is connected to the output terminal of the gate adapter 32 to receive a drive signal to control its on / off state. Its drain is connected to the parallel resonant unit 42, and its source is grounded. As a high-frequency switching device, the first field-effect transistor MOS1 adjusts the working state of the resonant circuit by controlling its own on / off timing, thereby realizing the frequency conversion adjustment of the heating power. The parallel resonant section 42 includes a filter group, a resonant capacitor group, a voltage sampling group, and a current sampling group. The filter group includes a first inductor L1, a third capacitor C3, and a forty-fifth capacitor C45. The first inductor L1 is a bus filter inductor, with one end connected to the +48V DC bus output by the input processing unit 1 and the other end connected to the resonant capacitor group. That is, the first inductor L1 is connected in series between the DC bus and the resonant circuit to provide DC power to the subsequent resonant circuit, while smoothing the bus current ripple and suppressing the high-frequency AC components of the resonant circuit from entering the preceding DC bus. The third capacitor C3 and the forty-fifth capacitor C45 are connected in parallel between the other end of the first inductor L1 and ground to filter out the high-frequency ripple of the resonant circuit, absorb switching surges, stabilize the DC potential of the circuit, and suppress electromagnetic interference. The resonant capacitor bank includes the twenty-sixth capacitor C26, the fifth capacitor C5, the thirty-fifth capacitor C35, the fourth capacitor C4, the eighth capacitor C8, and the thirty-third capacitor C33. Multiple capacitor banks are connected in parallel to form a resonant capacitor network, which is connected in parallel between the two output terminals OUT-A and OUT-B. OUT-A and OUT-B are used to connect an external electromagnetic heating coil, which acts as a resonant inductor and is connected in parallel with the resonant capacitor bank to form an LC parallel resonant circuit. The voltage sampling group includes the thirty-sixth resistor R36, the fifty-fifth resistor R55, and the fifteenth resistor R15. This branch is connected in parallel across the two ends of the LC parallel resonant circuit. The working voltage of the resonant circuit is stepped down and conditioned through a resistor voltage divider network. The voltage signal of the resonant circuit is collected in real time, and the high-amplitude voltage physical quantity is converted into a low-amplitude analog voltage signal that is adapted to the main control input. The signal is then sent to the corresponding pin of the first control chip U1 to provide the main control unit 5 with real-time monitoring data of resonant frequency, phase, and amplitude. This data is used for closed-loop frequency conversion control and zero-voltage soft switching condition judgment to ensure that the working frequency and resonant frequency are accurately matched and to stably achieve zero-voltage soft switching. The current sampling branch includes a 22nd resistor R22, a 31st resistor R31, a 1st resistor R5, a 26th resistor R26, and an 11th capacitor C11, a 14th capacitor C14, and a 15th capacitor C15 used as filter capacitors. This branch is connected in series to the current path of the LC parallel resonant circuit. The sampling resistor converts the operating current signal of the resonant circuit into a corresponding analog voltage signal, and outputs the current sampling signal to the pins OPIN and OPOUT of the first control chip U1 to assist the main control unit 5 in realizing full-dimensional monitoring of the operating status of the resonant circuit. In addition, the I / SUR current sampling signal is sent to the I / SUR pin of the first control chip U1. The main control unit 5 compares the voltage signal corresponding to the sampled current with the preset overcurrent protection threshold in real time. When the operating current of the resonant circuit exceeds the preset safety threshold, the main control unit immediately shuts off the PWM drive output of the pin PPGH, cuts off the drive signal of the SiC isolation drive unit, and then blocks all power output of the parallel resonant inverter unit to achieve rapid overcurrent protection, avoid the SiC power tube from burning out due to overcurrent and overload, and greatly improve the safety and reliability of the circuit operation. The parallel inverter resonant unit 4 in this embodiment adopts an LC parallel resonant topology, which can stably achieve zero-voltage soft switching under 48V low-voltage high-current conditions, significantly reducing switching losses and electromagnetic interference. It uses a single SiC transistor as the switching part 41, which has a simple circuit structure and low control difficulty. The voltage sampling group and the current sampling group work together to provide real-time feedback on the resonant state and form a closed-loop frequency control, which can be adapted to cookware loads of different materials and specifications. The built-in overcurrent protection mechanism has a fast response speed and can effectively protect the SiC power transistor, improving the overall reliability and heating stability of the machine.

[0037] Further, please refer to Figure 1 and Figure 2 The input processing unit 1 includes an input section 11, a filter section 12, and a reverse connection protection section 13. The input terminal of the input section 11 is used to connect to a 48V DC power supply, and the output terminal of the input section 11 is connected to the input terminal of the reverse connection protection section 13. The reverse connection protection section 13 is used to determine the input polarity. The input terminal of the filter section 12 is used to connect to a 48V DC power supply in parallel, and the output terminal of the filter section 12 is connected to the input terminal of the auxiliary power generation unit 2 and the main power supply terminal of the parallel resonant inverter unit 4, respectively.

[0038] In this embodiment, the input section 11 includes input terminals VIN+ and VIN-, which are used to connect to an external 48V DC power supply; The reverse connection protection section 13 includes three parallel MOSFETs: a third field-effect transistor (MOSFET3), a fourth field-effect transistor (MOSFET4), and a fifth field-effect transistor (MOSFET5). The gates, drains, and sources of the MOSFETs are interconnected and connected in series between the input section 11 and the filter section 12. When the input power supply polarity is correct, the MOSFETs are controlled to conduct, allowing the input current to flow normally. When the input power supply polarity is reversed, the MOSFETs are turned off, cutting off the current path and preventing damage to subsequent circuits due to reverse connection. The filter section 12 includes a seventh filter capacitor EC7, a tenth filter capacitor EC10, a sixth capacitor C6, and a transient voltage suppressor diode TVS3. The seventh filter capacitor EC7, the tenth filter capacitor EC10, and the sixth capacitor C6 are connected in parallel across the 48V DC bus to filter out input voltage ripple and high-frequency interference. The TVS3 is connected in parallel across the bus to quickly absorb surge voltage and protect downstream devices from high-voltage spike damage.

[0039] The present invention also provides a PCB board on which the parallel resonant induction cooker control circuit as described above is printed.

[0040] The present invention also provides an induction cooker, wherein the induction cooker uses a parallel resonant induction cooker control circuit as described above for operation control.

[0041] It is understood that those skilled in the art can make equivalent substitutions or changes to the technical solution and inventive concept of the present invention, and all such changes or substitutions should fall within the protection scope of the present invention.

Claims

1. A parallel resonant induction cooker control circuit, characterized in that, The system includes an input processing unit, an auxiliary power generation unit, a SiC isolation drive unit, a parallel resonant inverter unit, and a main control unit. The input terminal of the input processing unit is connected to a 48V DC power supply. The output terminal of the input processing unit is connected to the input terminal of the auxiliary power generation unit and the main power supply terminal of the parallel resonant inverter unit. The output terminal of the auxiliary power generation unit is connected to the power supply terminal of the SiC isolation drive unit, the control power supply terminal of the parallel resonant inverter unit, and the power supply terminal of the main control unit. The output terminal of the main control unit is connected to the input terminal of the SiC isolation drive unit, and the output terminal of the SiC isolation drive unit is connected to the control input terminal of the parallel resonant inverter unit. The power output terminal of the parallel resonant inverter unit is connected to an electromagnetic heating coil, and the feedback terminal of the parallel resonant inverter unit is connected to the resonant state feedback terminal of the main control unit.

2. The parallel resonant induction cooker control circuit according to claim 1, characterized in that, It also includes a temperature sampling unit and a fan drive unit; the input terminal of the temperature sampling unit is used to connect to a thermistor, and the output terminal of the temperature sampling unit is connected to the overheat detection terminal of the main control unit; the input terminal of the fan drive unit is connected to the first PWM output terminal of the main control unit, and the output terminal of the fan drive unit is used to connect to a cooling fan.

3. The parallel resonant induction cooker control circuit according to claim 1, characterized in that, The main control unit includes a first control chip U1, a communication unit, and a programming unit. The VDD and VCC pins of the first control chip U1 are connected to the output of the auxiliary power generation unit, the PPGH pin of the first control chip U1 is connected to the input of the SiC isolated drive unit, and the SYS-, SYS+, OPIN, OPOUT, and I / SUR pins of the first control chip U1 are connected to the feedback of the parallel resonant inverter unit. The communication unit is connected to the TXD and RXD pins of the first control chip U1, and the programming unit is connected to the ICPDA and ICPCK pins of the first control chip U1.

4. The parallel resonant induction cooker control circuit according to claim 3, characterized in that, The auxiliary power generation unit includes a first voltage conversion section, a second voltage conversion section, and a third voltage conversion section. The input terminal of the first voltage conversion section is connected to the output terminal of the input processing unit. The output terminal of the first voltage conversion section is connected to the input terminals of the second and third voltage conversion sections and the VCC pin of the first control chip U1, respectively, for outputting an 18V DC voltage. The output terminal of the second voltage conversion section is connected to the VDD pin of the first control chip U1, the power supply terminal of the communication section, the power supply terminal of the programming section, and the first power supply terminal of the SiC isolation driving unit, respectively, for outputting a 5V DC voltage. The output terminal of the third voltage conversion section is connected to the second power supply terminal of the SiC isolation driving unit, for outputting an 18V B voltage and a -4V voltage.

5. The parallel resonant induction cooker control circuit according to claim 3, characterized in that, The SiC isolated drive unit includes a second control chip U2, a drive unit, and a gate adapter unit. The input terminal of the drive unit is connected to the pin PPGH of the first control chip U1. The output terminal of the drive unit is connected to the pin IN+ of the second control chip U2. The pins OUTH and OUTL of the second control chip U2 are connected to the input terminal of the gate adapter unit. The output terminal of the gate adapter unit is connected to the control input terminal of the parallel resonant inverter unit.

6. The parallel resonant induction cooker control circuit according to claim 5, characterized in that, The parallel resonant inverter unit includes a switching section and a parallel resonant section; the output terminal of the gate adapter is connected to the gate terminal of the switching section, the drain terminal of the switching section is connected to the parallel resonant section, and the source terminal of the switching section is grounded; the power output terminal of the parallel resonant section is used to connect to the electromagnetic heating coil, and the feedback terminal of the parallel resonant section is connected to the pins SYS-, SYS+, OPIN, OPOUT, and I / SUR of the first control chip U1, respectively.

7. The parallel resonant induction cooker control circuit according to claim 6, characterized in that, The switching section includes a first field-effect transistor (MOSFET) MOS1, which is a SiC MOSFET. The parallel resonant section includes a filter group, a voltage sampling group, a current sampling group, and a resonant capacitor group. The gate of the first MOSFET MOS1 is connected to the output terminal of the gate adapter section, the drain of the first MOSFET MOS1 is connected to the other end of the resonant capacitor group, and the source of the first MOSFET MOS1 is grounded. The OUT pin of the resonant capacitor group is used to connect to the electromagnetic heating coil to form a resonant circuit. One end of the filter group is connected to the output terminal of the input processing unit and the input terminal of the current sampling group, and the other end of the filter group is connected to one end of the resonant capacitor group. The input terminal of the voltage sampling group is connected to the resonant circuit, the output terminal of the voltage sampling group is connected to the SYS- and SYS+ pins of the first control chip U1, and the output terminal of the current sampling group is connected to the OPIN, OPOUT, and I / SUR pins of the first control chip U1.

8. The parallel resonant induction cooker control circuit according to claim 1, characterized in that, The input processing unit includes an input section, a filtering section, and a reverse connection protection section. The input terminal of the input section is used to connect to a 48V DC power supply, and the output terminal of the input section is connected to the input terminal of the reverse connection protection section. The reverse connection protection section is used to determine the input polarity. The input terminal of the filtering section is used to connect to a 48V DC power supply in parallel, and the output terminal of the filtering section is connected to the input terminal of the auxiliary power generation unit and the main power supply terminal of the parallel resonant inverter unit, respectively.

9. A PCB board, characterized in that, The PCB board is printed with a parallel resonant induction cooker control circuit as described in any one of claims 1-8.

10. An induction cooker, characterized in that, The induction cooker is controlled by a parallel resonant induction cooker control circuit as described in any one of claims 1-8.

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