Motor driving circuit of soybean milk machine or homogenizer and control method thereof

Abstract

The application discloses a motor driving circuit of a soybean milk machine or a cell disruptor and a control method thereof, and relates to the technical field of the soybean milk machine or the cell disruptor. The motor driving circuit comprises a power supply circuit, a heating disc driving circuit and a motor driving circuit, and the heating disc driving circuit and the motor driving circuit are in communication with the power supply circuit. The motor driving circuit comprises a first thyristor, a second thyristor and a first relay which are connected in series. The control electrode of the first thyristor is connected with the collector of a first triode. The control electrode of the second thyristor is connected with the input end of a first chip. The output end of the first relay is connected with the collector of a second triode. The emitter of the first triode, the output end of the first chip and the emitter of the second triode are connected with a magnetron dry reed valve in series. The magnetron dry reed valve is grounded. The application can fully meet the new national standard opening cover safety requirements, greatly reduce the product modification cost, avoid major changes to the existing structure, improve the reliability of safety protection and design flexibility.

Description

Technical Field

[0001] This invention relates to the field of home appliance technology, and in particular to a motor drive circuit and control method for a soymilk maker or a blender. Background Technology

[0002] With the improvement of living standards, small kitchen appliances such as soy milk makers and blenders have become commonplace. These products are usually equipped with high-speed rotating blades, and the safety of opening the lid has become a major concern. To prevent users or pets from being injured by contact with the blades when the machine is running, relevant national mandatory safety standards (hereinafter referred to as "new national standards") have clearly required that products must have reliable power-off protection when the lid is opened, and that the motor drive system must have extremely high fault tolerance.

[0003] Currently, existing technologies involve directly installing a micro switch or high-voltage switch at the product's handle. When the cover is opened, this switch physically cuts off the power supply circuit for the entire machine or the motor load. While this meets the technical requirements of the new national standard, for products already designed and mass-produced according to the old standard, a complete overhaul of the handle and its cover structure is required. Essentially, it necessitates redesigning and remolding, resulting in high upgrade costs.

[0004] Furthermore, the switch at the handle needs to withstand a high-temperature steam environment, requiring extremely high levels of waterproofing and moisture resistance. This results in expensive and bulky switch devices that meet the requirements. The installation of large-volume switches limits the freedom of industrial design in terms of product appearance, and the assembly process is also more complex.

[0005] Therefore, it is urgent to research and develop a motor drive circuit and control method for a soymilk maker or a blender to solve the above-mentioned technical problems. Summary of the Invention

[0006] The purpose of this invention is to provide a motor drive circuit and control method for a soymilk maker or a blender. This motor drive circuit and control method can fully meet the new national standard for lid opening safety requirements while significantly reducing product modification costs, avoiding major changes to the existing structure, and improving the reliability and design flexibility of safety protection.

[0007] To achieve the above objectives, the present invention provides a motor drive circuit for a soymilk maker or a high-speed blender, the specific implementation of which is as follows:

[0008] A motor drive circuit for a soymilk maker or a blender includes a power supply circuit, a heating plate drive circuit, and a motor drive circuit, wherein the heating plate drive circuit and the motor drive circuit are both connected to the power supply circuit.

[0009] The motor drive circuit includes a first thyristor, a second thyristor, and a first relay connected in series, with the output of the first relay connected to the motor.

[0010] The control electrode of the first thyristor is connected to the collector of the first transistor, the control electrode of the second thyristor is connected to the input terminal of the first chip, and the output terminal of the first relay is connected to the collector of the second transistor.

[0011] The emitter of the first transistor, the output terminal of the first chip, and the emitter of the second transistor are connected in series with a magnetic reed switch, which is grounded.

[0012] This invention discloses a motor drive circuit for a soymilk maker or blender. Compared to existing technologies, this circuit connects the control circuits of three drive components (a first thyristor, a second thyristor, and a first relay) in series with a magnetic reed switch and grounds them. When the product is opened, causing the magnetic reed switch to mechanically disconnect, the control current circuits of all three drive components can be physically and completely cut off simultaneously. This ensures that even in extreme cases where the microcontroller in the control circuit of the soymilk maker or blender experiences program malfunction, crash, or damage, the motor will never be driven. This fundamentally meets the highest level of "fail-safe" protection requirements of the new national standard after the lid is opened, providing absolute hardware-level safety for users and pets.

[0013] In some embodiments, a detection circuit is also included, which includes a pull-up resistor and an isolation diode;

[0014] The positive terminal of the pull-up resistor is connected to the output terminal of the power supply circuit, and the negative terminal is connected to the anode of the isolation diode. The anode of the isolation diode is connected to the detection terminal of the microcontroller, and the detection terminal of the microcontroller is grounded through a magnetic reed switch.

[0015] The cathode of the isolation diode is connected to the series connection node of the emitter of the first transistor, the output terminal of the first chip, and the emitter of the second transistor.

[0016] By adding an independent detection circuit, the microcontroller of the soymilk maker or blender can detect the on / off state of the magnetic reed switch in real time and accurately. When the lid is closed (reed switch closed), the microcontroller detects a low level; when the lid is open (reed switch open), the microcontroller detects a high level. Based on this, status prompts (such as display, alarm), logic control (such as locking other functions), or fault recording can be performed, which greatly improves the user experience and safety warning capabilities of the product.

[0017] In some embodiments, the detection circuit further includes an isolation resistor, the positive terminal of which is connected to the negative terminal of the pull-up resistor and the anode of the isolation diode, and the negative terminal of the isolation resistor is used to connect to the detection terminal of the microcontroller.

[0018] By adding an isolation resistor, current limiting protection is provided for the detection circuit, preventing damage to the I / O ports of the microcontroller in the detection node or the control circuit of the soymilk maker / blender due to unexpected situations (such as high voltage crosstalk or static electricity). This enhances the reliability and anti-interference capability of the entire detection circuit and ensures the long-term stability and accuracy of the status detection signal.

[0019] In some embodiments, the power supply circuit includes a power input module, an electromagnetic compatibility module, and a power supply module connected in sequence. The output terminal of the power supply module is connected to a terminal block, which is connected to the input terminal of the motor drive circuit.

[0020] The power input module includes an AC live wire, an AC neutral wire, a power ground wire, a fuse, and a varistor. The AC live wire, AC neutral wire, and power ground wire are all connected to the electromagnetic compatibility module. The fuse is located on the AC live wire. The positive terminal of the varistor is connected to the AC live wire, and the negative terminal is connected to the AC neutral wire.

[0021] The electromagnetic compatibility module includes a safety X capacitor, a common-mode inductor, a first Y capacitor, and a second Y capacitor. The safety X capacitor is connected in parallel with the varistor. The first coil input terminal of the common-mode inductor is connected to the AC live wire, and the first Y capacitor is connected in series at the first coil output terminal. The other end of the first Y capacitor is connected to the power ground wire. The second coil output terminal of the common-mode inductor is connected to the AC neutral wire, and the second Y capacitor is connected in series at the input terminal. The other end of the second Y capacitor is connected to the power ground wire.

[0022] By integrating input protection with fuses and varistors, and an EMC filter network including safety X capacitors, first Y capacitors, second Y capacitors and common mode inductors, it can effectively absorb power grid surges and suppress electromagnetic interference, ensuring stable operation of the product itself without polluting the power grid, and meeting the national mandatory electromagnetic compatibility (EMC) standards.

[0023] In some embodiments, the heating plate driving circuit includes a second relay, a driving transistor, and a freewheeling diode. One end of the coil of the second relay is connected to the terminal block and the cathode of the freewheeling diode, and is connected to the output terminal of the power supply circuit through the terminal block. The other end is connected to the collector of the driving transistor and the anode of the freewheeling diode. The base of the driving transistor is connected to the pin of the terminal block that controls the heating plate through a first resistor. The transmitter of the driving transistor is grounded.

[0024] The normally open contact of the second relay includes a first terminal and a second terminal. The first terminal is connected to a first connection terminal through the safety X capacitor. The first connection terminal is connected to one end of the heating plate, and the second terminal is connected to the other end of the heating plate.

[0025] The freewheeling diode protects the drive transistor from the impact of reverse electromotive force when the relay coil is de-energized, and the safety X capacitor is reused and connected between the relay contacts and the heating plate, which absorbs contact sparks, reduces switching electromagnetic interference (EMI), extends the mechanical life of the relay, and further improves the EMC performance of the product.

[0026] In some embodiments, zero-crossing circuits and discharge circuits are also included;

[0027] The zero-crossing circuit includes a first voltage divider resistor, a second voltage divider resistor, a third voltage divider resistor, a detection transistor, and a pull-up resistor; the first voltage divider resistor, the second voltage divider resistor, and the third voltage divider resistor are connected in series in sequence, one end of the first voltage divider resistor is connected to the AC live wire through the common mode inductor, and is connected to a first connection point, which is connected to the AC neutral wire;

[0028] The base of the detection transistor is connected to the third voltage divider resistor, the emitter is grounded, the collector is connected to the pull-up resistor, the other end of the pull-up resistor is connected to the output terminal of the power supply module, and the collector of the detection transistor is connected to the terminal block for connecting to the microcontroller zero-crossing detection module of the control circuit.

[0029] The power-off discharge circuit includes a discharge diode, the anode of which is grounded and the cathode is connected to the third voltage divider resistor and the base of the detection transistor.

[0030] By incorporating a zero-crossing circuit and a discharge circuit, the zero-crossing circuit can accurately detect the zero-crossing point of the AC mains power, providing a timing reference for the on / off switching of the microcontroller-controlled electrical components (such as the second relay) in the control circuit of the soymilk maker or blender near the zero-crossing point. This greatly reduces the arcing sparks when the relay contacts are switched on and off, significantly extends the relay life, and reduces switching noise. When the product is unplugged, the discharge circuit provides a safe discharge path for the high-voltage filter capacitor in the power module, ensuring that the voltage across the plug is discharged below a safe value within a specified safe time (such as 1 second), meeting safety regulations and preventing electric shock hazards when users touch the plug.

[0031] In some embodiments, the power supply module includes a surge resistor, a second chip, an input high-voltage electrolytic capacitor, an energy storage inductor, an output low-voltage electrolytic capacitor, a dummy load resistor, and an output high-frequency filter capacitor.

[0032] One end of the surge resistor is connected to the output terminal of the common mode inductor, and the other end is connected to the second chip;

[0033] The positive terminal of the input high-voltage electrolytic capacitor is connected to the second chip, the negative terminal is connected to one end of the energy storage inductor, and the other end of the energy storage inductor is connected to the second chip;

[0034] The negative terminal of the low-voltage electrolytic capacitor is connected to the ground terminal of the second chip, and the positive terminal is the output terminal of the power supply module, which is connected to the terminal block.

[0035] The dummy load resistor and the output high-frequency filter capacitor are both connected in parallel with the output low-voltage electrolytic capacitor.

[0036] The surge resistor limits the inrush current, and the input high-voltage electrolytic capacitor, the output low-voltage electrolytic capacitor, and the energy storage inductor are used for filtering and energy storage to generate a stable and clean low-voltage DC power supply for the electrical components in the subsequent circuit. The dummy load resistor ensures the stability of the power supply under no-load or light-load conditions, and the output high-frequency filter capacitor further filters out high-frequency switching noise.

[0037] In some embodiments, a mains voltage detection circuit is also included;

[0038] The mains voltage detection circuit includes a fourth voltage divider resistor, a fifth voltage divider resistor, a sixth voltage divider resistor, and a seventh voltage divider resistor connected in series, as well as a first filter capacitor. One end of the fourth voltage divider resistor is connected to the second chip to introduce a voltage signal from the AC mains, and the other end of the seventh voltage divider resistor is grounded.

[0039] The sixth and seventh voltage divider resistors are connected in series to a signal output node, which is connected to the pin for mains power detection in the terminal block. The first filter capacitor is connected in parallel with the seventh voltage divider resistor, with one end grounded and the other end connected to the signal output node.

[0040] By using multiple voltage divider resistors connected in series to divide the voltage, the circuit's withstand voltage and safety are enhanced. After being filtered by the first filter capacitor, the mains voltage information is transmitted linearly and with low ripple to the microcontroller of the control circuit of the soymilk maker or blender. This allows the microcontroller to work with existing control algorithms to control the impact of heating plate power and motor speed, thereby ensuring the consistency and stability of the product's performance (such as heating efficiency and pulverizing effect) under different power grid environments.

[0041] In some embodiments, a temperature detection and buzzer circuit is also included; the temperature detection and buzzer circuit includes a sensor terminal, an eighth voltage divider resistor, a ninth voltage divider resistor, a second filter capacitor, a buzzer, and a DC blocking capacitor;

[0042] The sensor terminal is used to connect an external temperature sensor. One end of the sensor is connected to the output terminal of the power supply module, and the other end is connected to a multiplexed circuit node. The multiplexed circuit node is connected to the wiring terminal.

[0043] The eighth voltage divider resistor is connected between the multiplexing circuit node and the sensor terminal. The ninth voltage divider resistor is connected in parallel with the second filter capacitor. One end of the parallel branch is connected between the eighth voltage divider resistor and the sensor terminal, and the other end is grounded.

[0044] One end of the buzzer is connected in series with the DC blocking capacitor, and the other end is grounded. The other end of the DC blocking capacitor is connected to the multiplexing circuit node.

[0045] By reusing circuit nodes, the circuit can be used to read the analog voltage signal of the NTC temperature sensor to achieve accurate temperature detection and control (such as anti-overflow, anti-dry burning, and programmed heating), and also to output drive signals to make the buzzer sound to indicate the working status or alarm. This effectively saves the pin resources of the microcontroller in the control circuit of the soymilk maker or blender, as well as the number of connector (ribbon cable) pins on the control circuit. While ensuring functional integrity, it reduces system complexity and hardware cost.

[0046] The present invention also provides a motor drive control method for use in the motor drive circuit of the above-mentioned soymilk maker or blender, comprising the following steps:

[0047] Status detection step: The detection circuit continuously detects the on / off state of the magnetic reed switch, generates and outputs a status detection signal to the microcontroller of the control circuit of the soymilk maker or blender;

[0048] Safety judgment steps: The microcontroller in the control circuit determines whether the device is in an open or closed state based on the status detection signal;

[0049] Drive control steps: When the microcontroller of the control circuit determines that the device is in a closed state, it outputs drive signals to the first transistor, the first chip and the second transistor respectively to control the on and off of the first thyristor, the second thyristor and the first relay, thereby driving the motor to work.

[0050] Fault safety protection steps: When the device is opened, causing the magnetic reed switch to mechanically disconnect, the drive control circuit connected in series with the emitter of the first transistor, the output terminal of the first chip, and the emitter of the second transistor is physically cut off. All drive signals output by the control circuit fail, and the first thyristor, the second thyristor, and the first relay cannot conduct, causing the motor to stop running.

[0051] Based on the above technical solution, the present invention has the following beneficial effects compared with the prior art:

[0052] By connecting the control circuits of the three drive components (first thyristor, second thyristor, and first relay) in series with a magnetic reed switch and grounding them, when the product is opened, causing the magnetic reed switch to mechanically disconnect, the control current circuits of all three drive components can be physically and completely cut off simultaneously. This ensures that even in extreme cases where the microcontroller in the control circuit of the soymilk maker or blender experiences program malfunction, crash, or damage, the motor will absolutely not be driven. This fundamentally meets the highest level of "fail-safe" protection requirements of the new national standard after the lid is opened, providing absolute hardware-level safety for users and pets. Attached Figure Description

[0053] Figure 1 This is a schematic diagram of the power supply circuit of the present invention;

[0054] Figure 2 This is a schematic diagram of the motor drive circuit of the present invention;

[0055] Figure 3 This is a schematic diagram showing the cooperation between the power supply circuit and the heating plate drive motor of the present invention;

[0056] Figure 4 This is a schematic diagram showing the combination of the power supply circuit, zero-crossing circuit, and voltage relief circuit of the present invention.

[0057] Figure 5 This is a schematic diagram showing the cooperation between the power supply circuit and the mains voltage detection circuit of the present invention;

[0058] Figure 6 This is a schematic diagram of the temperature detection and buzzer indication circuit of the present invention;

[0059] Figure 7 This is a schematic diagram of the wiring terminals of the present invention.

[0060] Explanation of reference numerals in the attached figures: 100. Power supply circuit; ACL, AC live wire; ACN, AC neutral wire; PE, power ground wire; F1, fuse; RV1, varistor; CX1, safety X capacitor; CY1, first Y capacitor; CY2, second Y capacitor; LG2, common mode inductor; R1, surge resistor; U1, second chip; E1, input high voltage electrolytic capacitor; LG1, energy storage inductor; E2, output low voltage electrolytic capacitor; R6, dummy load resistor; C1, output high frequency filter capacitor; M2, motor; 200. Heating plate drive circuit; K1. Second relay; Q1. Drive transistor; D1. Freewheeling diode; R2. First resistor; 300. Motor drive circuit; QR1, first thyristor; QR2, second thyristor; K2, first relay; Q3, first transistor; U2, first chip; Q4, second transistor; SW, reed switch; 400, Detection circuit; R22, First pull-up resistor; D4, Isolation diode; R23, Isolation resistor; 510, Zero-crossing circuit; R3, First voltage divider resistor; R4, Second voltage divider resistor; R5, Third voltage divider resistor; Q2, Sensing transistor; R13, Second pull-up resistor; 511, First connection point; 520, Bleeding circuit; D2, Bleeding diode; 600, Mains voltage detection circuit; R7, Fourth voltage divider resistor; R8, Fifth voltage divider resistor; R9, Sixth voltage divider resistor; R10, Seventh voltage divider resistor; C3, First filter capacitor; SYS, Signal output node; 700, Temperature detection and buzzer indication circuit; NTC, Sensor terminal; R11, Eighth voltage divider resistor; R12, Ninth voltage divider resistor; C2, Second filter capacitor; BUZ1, Buzzer; C4, DC blocking capacitor; H1, First connection terminal; H2, Second connection terminal; CN1, Wiring terminal; NT / B, Multiplexed circuit node. Detailed Implementation

[0061] To facilitate understanding of the present invention, specific embodiments of the present invention will be described in more detail below with reference to the accompanying drawings.

[0062] Unless otherwise specified or defined, the terms "first," "second," etc., used in this document are for distinguishing names only and do not represent a specific number or order.

[0063] Unless otherwise stated or defined, the term “and / or” as used herein includes any and all combinations of one or more of the related listed items.

[0064] It should be noted that in this article, "fixed to" or "connected to" can mean directly fixed to or connected to a component, or indirectly fixed to or connected to a component.

[0065] Example 1:

[0066] like Figure 1-7 As shown, the motor drive circuit of a soymilk maker or blender provided in this embodiment includes a power supply circuit 100, a heating plate drive circuit 200 and a motor drive circuit 300, wherein the heating plate drive circuit 200 and the motor drive circuit 300 are both connected to the power supply circuit 100.

[0067] The motor drive circuit 300 includes a first thyristor QR1, a second thyristor QR2, and a first relay K2 connected in series. The output of the first relay K2 is connected to the motor.

[0068] The control electrode of the first thyristor QR1 is connected to the collector of the first transistor Q3, the control electrode of the second thyristor QR2 is connected to the input terminal of the first chip U2, and the output terminal of the first relay K2 is connected to the collector of the second transistor Q4.

[0069] The emitter of the first transistor Q3, the output terminal of the first chip U2, and the emitter of the second transistor Q4 are connected in series with a magnetic reed switch SW, which is grounded.

[0070] In some embodiments, a detection circuit 400 is also included, which includes a first pull-up resistor R22 and an isolation diode D4;

[0071] The positive terminal of the first pull-up resistor R22 is connected to the output terminal of the power supply circuit 100, and the negative terminal is connected to the anode of the isolation diode D4. The anode of the isolation diode D4 is connected to the detection terminal of the microcontroller, and the detection terminal of the microcontroller is grounded through the magnetic reed switch SW.

[0072] The cathode of the isolation diode D4 is connected to the series connection node of the emitter of the first transistor Q3, the output terminal of the first chip U2, and the emitter of the second transistor Q4.

[0073] By adding an independent detection circuit 400, the microcontroller of the soymilk maker or blender can detect the on / off state of the magnetic reed switch SW in real time and accurately. When the lid is closed (magnetic reed switch SW is closed), the microcontroller detects a low level; when the lid is open (magnetic reed switch SW is open), the microcontroller detects a high level. Based on this, status prompts (such as display, alarm), logic control (such as locking other functions), or fault recording can be performed, which greatly improves the user experience and safety warning capabilities of the product.

[0074] In some embodiments, the detection circuit 400 further includes an isolation resistor R23, the positive terminal of which is connected to the negative terminal of the first pull-up resistor R22 and the anode of the isolation diode D4, and the negative terminal of the isolation resistor R23 is used to connect to the detection terminal of the microcontroller.

[0075] By adding isolation resistor R23, current limiting protection is provided for detection circuit 400, preventing the I / O port of the microcontroller in the detection node or control circuit of the soymilk maker / blender from being damaged due to unexpected situations (such as high voltage crosstalk or static electricity). This enhances the reliability and anti-interference capability of the entire detection circuit 400, ensuring the long-term stability and accuracy of the status detection signal.

[0076] In some embodiments, the power supply circuit 100 includes a power input module, an electromagnetic compatibility module, and a power supply module connected in sequence. The output terminal of the power supply module is connected to a terminal CN1, and the terminal CN1 is connected to the input terminal of the motor drive circuit 300.

[0077] The power input module includes an AC live wire ACL, an AC neutral wire ACN, a power ground wire PE, a fuse F1, and a varistor RV1. The AC live wire ACL, AC neutral wire ACN, and power ground wire PE are all connected to the electromagnetic compatibility module. The fuse F1 is located on the AC live wire ACL. The positive terminal of the varistor RV1 is connected to the AC live wire ACL, and the negative terminal is connected to the AC neutral wire ACN.

[0078] The electromagnetic compatibility module includes a safety X capacitor CX1, a common-mode inductor LG2, a first Y capacitor CY1, and a second Y capacitor CY2. The safety X capacitor CX1 is connected in parallel with the varistor RV1. The first coil input terminal of the common-mode inductor LG2 is connected to the AC live wire ACL, and the first Y capacitor CY1 is connected in series at the first coil output terminal. The other end of the first Y capacitor CY1 is connected to the power ground wire PE. The second coil output terminal of the common-mode inductor LG2 is connected to the AC neutral wire ACN, and the second Y capacitor CY2 is connected in series at the input terminal. The other end of the second Y capacitor CY2 is connected to the power ground wire PE.

[0079] By integrating the input protection of fuse F1 and varistor RV1, and the EMC filtering network including safety X capacitor CX1, first Y capacitor CY1, second Y capacitor CY2 and common mode inductor LG2, it can effectively absorb power grid surges, suppress electromagnetic interference, ensure stable operation of the product itself and not cause pollution to the power grid, and meet the national mandatory electromagnetic compatibility (EMC) standards.

[0080] In some embodiments, the heating plate driving circuit 200 includes a second relay K1, a driving transistor Q1, and a freewheeling diode D1. One end of the coil of the second relay K1 is connected to the terminal CN1 and the cathode of the freewheeling diode D1, and is connected to the output terminal of the power supply circuit 100 through the terminal CN1. The other end is connected to the collector of the driving transistor Q1 and the anode of the freewheeling diode D1. The base of the driving transistor Q1 is connected to the pin controlling the heating plate in the terminal CN1 through a first resistor. The transmitter of the driving transistor Q1 is grounded.

[0081] The normally open contact of the second relay K1 includes a first terminal and a second terminal. The first terminal is connected to a first connection terminal H1 through the safety capacitor CX1. The first connection terminal H1 is connected to one end of the heating plate, and the second terminal is connected to the other end of the heating plate.

[0082] The freewheeling diode D1 protects the drive transistor Q1 from the impact of the reverse electromotive force when the relay coil is de-energized. The safety capacitor CX1 is multiplexed between the relay contacts and the heating plate, which absorbs contact sparks, reduces switching electromagnetic interference (EMI), extends the mechanical life of the relay, and further improves the EMC performance of the product.

[0083] In some embodiments, a zero-crossing circuit 510 and a discharge circuit 520 are also included;

[0084] The zero-crossing circuit 510 includes a first voltage divider resistor R3, a second voltage divider resistor R4, a third voltage divider resistor R5, a detection transistor Q2, and a first pull-up resistor R22; the first voltage divider resistor R3, the second voltage divider resistor R4, and the third voltage divider resistor R5 are connected in series in sequence, one end of the first voltage divider resistor R3 is connected to the AC live wire ACL through the common mode inductor LG2, and is connected to a first connection point, which is connected to the AC neutral wire ACN;

[0085] The base of the detection transistor Q2 is connected to the third voltage divider resistor R5, the emitter is grounded, and the collector is connected to the first pull-up resistor R22. The other end of the first pull-up resistor R22 is connected to the output terminal of the power supply module, and the collector of the detection transistor Q2 is connected to the terminal CN1 for connecting to the microcontroller zero-crossing detection module of the control circuit.

[0086] The power-off discharge circuit 520 includes a discharge diode D2, the anode of which is grounded and the cathode is connected to the third voltage divider resistor R5 and the base of the detection transistor Q2.

[0087] By setting up a zero-crossing circuit 510 and a discharge circuit 520, the zero-crossing circuit 510 can accurately detect the zero-crossing point of the AC mains power, providing a timing reference for the switching of the microcontroller-controlled electrical components (such as the second relay K1) in the control circuit of the soymilk maker or blender near the zero-crossing point. This greatly reduces the arcing sparks when the relay contacts are switched on and off, significantly extends the relay life, and reduces switching noise. When the product is unplugged, the discharge circuit 520 can provide a safe discharge path for the high-voltage filter capacitor in the power module, ensuring that the voltage across the plug is discharged to below a safe value within a safe time (such as 1 second), meeting safety requirements and preventing electric shock hazards when the user touches the plug.

[0088] In some embodiments, the power supply module includes a surge resistor R1, a second chip U1, an input high-voltage electrolytic capacitor E1, an energy storage inductor LG1, an output low-voltage electrolytic capacitor E2, a dummy load resistor R6, and an output high-frequency filter capacitor C1.

[0089] One end of the surge resistor R1 is connected to the output terminal of the common mode inductor LG2, and the other end is connected to the second chip U1;

[0090] The positive terminal of the input high-voltage electrolytic capacitor E1 is connected to the second chip U1, the negative terminal is connected to one end of the energy storage inductor LG1, and the other end of the energy storage inductor LG1 is connected to the second chip U1.

[0091] The negative terminal of the low-voltage electrolytic capacitor E2 is connected to the ground terminal of the second chip U1, and the positive terminal is the output terminal of the power supply module, which is connected to the terminal CN1.

[0092] The dummy load resistor R6 and the output high-frequency filter capacitor C1 are both connected in parallel with the output low-voltage electrolytic capacitor E2.

[0093] The surge resistor R1 limits the starting inrush current. The input high-voltage electrolytic capacitor E1, the output low-voltage electrolytic capacitor E2, and the energy storage inductor LG1 are used for filtering and energy storage to generate a stable and clean low-voltage DC power supply for the electrical components in the subsequent circuit. The dummy load resistor R6 is used to ensure the stability of the power supply under no-load or light-load conditions. The output high-frequency filter capacitor C1 further filters out high-frequency switching noise.

[0094] In some embodiments, a mains voltage detection circuit 600 is also included;

[0095] The mains voltage detection circuit 600 includes a fourth voltage divider resistor R7, a fifth voltage divider resistor R8, a sixth voltage divider resistor R9 and a seventh voltage divider resistor R10 connected in series, and a first filter capacitor C3. One end of the fourth voltage divider resistor R7 is connected to the second chip U1 to introduce the voltage signal of the AC mains, and the other end of the seventh voltage divider resistor R10 is grounded.

[0096] The sixth voltage divider resistor R9 and the seventh voltage divider resistor R10 are connected in series to a signal output node SYS. The signal output node SYS is connected to the pin in the terminal CN1 used for mains power detection. The first filter capacitor C3 is connected in parallel with the seventh voltage divider resistor R10, with one end grounded and the other end connected to the signal output node SYS.

[0097] By using multiple voltage divider resistors connected in series to divide the voltage, the circuit's withstand voltage and safety are enhanced. After being filtered by the first filter capacitor C3, the mains voltage information is transmitted linearly and with low ripple to the microcontroller of the control circuit of the soymilk maker or blender. This allows the microcontroller to work with existing control algorithms to control the impact of heating plate power and motor speed, thereby ensuring the consistency and stability of the product's performance (such as heating efficiency and pulverizing effect) under different power grid environments.

[0098] In some embodiments, a temperature detection and buzzer circuit 700 is also included; the temperature detection and buzzer circuit 700 includes a sensor terminal NTC, an eighth voltage divider resistor R11, a ninth voltage divider resistor R12, a second filter capacitor C2, a buzzer BUZ1, and a DC blocking capacitor C4.

[0099] The sensor terminal NTC is used to connect an external temperature sensor. One end of the sensor is connected to the output terminal of the power supply module, and the other end is connected to a multiplexed circuit node NT / B. The multiplexed circuit node NT / B is connected to the terminal CN1.

[0100] The eighth voltage divider resistor R11 is connected between the multiplexing circuit node NT / B and the sensor terminal NTC. The ninth voltage divider resistor R12 is connected in parallel with the second filter capacitor C2. One end of the parallel branch is connected between the eighth voltage divider resistor R11 and the sensor terminal NTC, and the other end is grounded.

[0101] One end of the buzzer BUZ1 is connected in series with the DC blocking capacitor C4, and the other end is grounded. The other end of the DC blocking capacitor C4 is connected to the multiplexing circuit node NT / B.

[0102] By reusing the circuit node NT / B, the circuit can be used to both read the analog voltage signal from the NTC temperature sensor for accurate temperature detection and control (such as anti-overflow, anti-dry burning, and programmed heating) and output a drive signal to make the buzzer BUZ1 sound to indicate the working status or alarm. This effectively saves the pin resources of the microcontroller in the control circuit of the soymilk maker or blender, as well as the number of connector (ribbon cable) pins on the control circuit. While ensuring functional integrity, it reduces system complexity and hardware cost.

[0103] The microcontrollers mentioned in this embodiment are all microcontrollers used in the control circuits of soy milk makers or blenders.

[0104] The second thyristor QR2 described in this embodiment can be replaced by a relay.

[0105] Example 2:

[0106] This embodiment provides a motor drive control method applied to the motor drive circuit of the soymilk maker or blender described in Embodiment 1, including the following steps:

[0107] Status detection steps: The detection circuit 400 continuously detects the on / off state of the magnetic reed switch SW, generates and outputs a status detection signal to the microcontroller of the control circuit of the soymilk maker or blender;

[0108] Safety judgment steps: The microcontroller in the control circuit determines whether the device is in an open or closed state based on the status detection signal;

[0109] Drive control steps: When the microcontroller of the control circuit determines that the device is in a closed state, it outputs drive signals to the first transistor Q3, the first chip U2 and the second transistor Q4 respectively to control the on and off of the first thyristor QR1, the second thyristor QR2 and the first relay K2, thereby driving the motor M2 to work.

[0110] Fault safety protection steps: When the equipment is opened, causing the magnetic reed switch SW to mechanically disconnect, the drive control circuit connected in series with the emitter of the first transistor Q3, the output terminal of the first chip U2, and the emitter of the second transistor Q4 is physically cut off. All drive signals output by the control circuit fail, and the first thyristor QR1, the second thyristor QR2, and the first relay K2 cannot be turned on, and the motor M2 stops running.

[0111] The motor drive circuit for a soymilk maker or blender provided by this invention, compared with the prior art, connects the control circuit of three drive elements (first thyristor QR1, second thyristor QR2, and first relay K2) in series with a magnetic reed switch SW and grounds it. When the product is opened, causing the magnetic reed switch SW to mechanically disconnect, the control current circuit of all three drive elements can be physically and completely cut off simultaneously and completely. This ensures that even in extreme cases where the microcontroller of the control circuit of the soymilk maker or blender experiences program disorder, crash, or damage, the motor can never be driven. Thus, it fundamentally meets the highest level of protection requirements for "fail-safe" after the lid is opened in the new national standard, providing absolute hardware-level safety for users and pets.

[0112] Based on the disclosure and teachings of the foregoing specification, those skilled in the art can make changes and modifications to the above embodiments. Therefore, the present invention is not limited to the specific embodiments disclosed and described above, and some modifications and changes to the present invention should also fall within the protection scope of the claims of the present invention. Furthermore, although some specific terms are used in this specification, these terms are only for convenience of explanation and do not constitute any limitation on the present invention.

Claims

1. A motor drive circuit for a soymilk maker or a blender, characterized in that, It includes a power supply circuit (100), a heating plate drive circuit (200), and a motor drive circuit (300), wherein the heating plate drive circuit (200) and the motor drive circuit (300) are both connected to the power supply circuit (100); The motor drive circuit (300) includes a first thyristor (QR1), a second thyristor (QR2), and a first relay (K2) connected in series. The output of the first relay (K2) is connected to the motor (M2). The control electrode of the first thyristor (QR1) is connected to the collector of the first transistor (Q3), the control electrode of the second thyristor (QR2) is connected to the input terminal of the first chip (U2), and the output terminal of the first relay (K2) is connected to the collector of the second transistor (Q4). The emitter of the first transistor (Q3), the output terminal of the first chip (U2), and the emitter of the second transistor (Q4) are connected in series with a magnetic reed switch (SW), which is grounded.

2. The motor drive circuit for a soymilk maker or blender as described in claim 1, characterized in that, It also includes a detection circuit (400), which includes a first pull-up resistor (R22) and an isolation diode (D4); The positive terminal of the first pull-up resistor (R22) is connected to the output terminal of the power supply circuit (100), and the negative terminal is connected to the anode of the isolation diode (D4). The anode of the isolation diode (D4) is connected to the detection terminal of the microcontroller, and the detection terminal of the microcontroller is grounded through a magnetic reed switch (SW). The cathode of the isolation diode (D4) is connected to the series connection node of the emitter of the first transistor (Q3), the output terminal of the first chip (U2), and the emitter of the second transistor (Q4).

3. The motor drive circuit for a soymilk maker or blender as described in claim 2, characterized in that, The detection circuit (400) further includes an isolation resistor (R23), the positive terminal of which is connected to the negative terminal of the pull-up resistor (R13) (R22) and the anode of the isolation diode (D4), and the negative terminal of the isolation resistor (R23) is used to connect to the detection terminal of the microcontroller.

4. The motor drive circuit of the soymilk maker or blender as described in any one of claims 1-3, characterized in that, The power supply circuit (100) includes a power input module, an electromagnetic compatibility module and a power supply module connected in sequence. The output terminal of the power supply module is connected to a terminal block (CN1), and the terminal block (CN1) is connected to the input terminal of the motor drive circuit (300). The power input module includes an AC live wire (ACL), an AC neutral wire (ACN), a power ground wire (PE), a fuse (F1), and a varistor (RV1). The AC live wire (ACL), AC neutral wire (ACN), and power ground wire (PE) are all connected to the electromagnetic compatibility module. The fuse (F1) is located on the AC live wire (ACL). The positive terminal of the varistor (RV1) is connected to the AC live wire (ACL), and the negative terminal is connected to the AC neutral wire (ACL). The electromagnetic compatibility module includes a safety X capacitor (CX1), a common mode inductor (LG2), a first Y capacitor (CY1), and a second Y capacitor (CY2). The safety X capacitor (CX1) is connected in parallel with the varistor (RV1). The first coil input terminal of the common mode inductor (LG2) is connected to the AC live wire (ACL), and the first Y capacitor (CY1) is connected in series at the first coil output terminal. The other end of the first Y capacitor (CY1) is connected to the power ground wire. The second coil output terminal of the common mode inductor (LG2) is connected to the AC neutral wire (ACN), and the second Y capacitor (CY2) is connected in series at the input terminal. The other end of the second Y capacitor (CY2) is connected to the power ground wire (PE).

5. The motor drive circuit for a soymilk maker or blender as described in claim 4, characterized in that, The heating plate driving circuit (200) includes a second relay (K1), a driving transistor (Q1), and a freewheeling diode (D1). One end of the coil of the second relay (K1) is connected to the terminal block (CN1) and the cathode of the freewheeling diode (D1), and is connected to the output terminal of the power supply circuit (100) through the terminal block (CN1). The other end is connected to the collector of the driving transistor (Q1) and the anode of the freewheeling diode (D1). The base of the driving transistor (Q1) is connected to the pin of the terminal block (CN1) that controls the heating plate through the first resistor (R2). The transmitter of the driving transistor (Q1) is grounded. The normally open contact of the second relay (K1) includes a first terminal and a second terminal. The first terminal is connected to a first connection terminal (H1) through the safety X capacitor (CX1). The first connection terminal (H1) is connected to one end of the heating plate, and the second terminal is connected to the other end of the heating plate.

6. The motor drive circuit for a soymilk maker or blender as described in claim 5, characterized in that, It also includes a zero-crossing circuit (510) and a discharge circuit (520); The zero-crossing circuit (510) includes a first voltage divider resistor (R3), a second voltage divider resistor (R4), a third voltage divider resistor (R5), a sensing transistor (Q2), and pull-up resistors (R13) (R22). The first voltage divider resistor (R3), the second voltage divider resistor (R4), and the third voltage divider resistor (R5) are connected in series. One end of the first voltage divider resistor (R3) is connected to the AC live wire through the common mode inductor (LG2) and is connected to a first connection point (511). The first connection point (511) is connected to the AC neutral wire (ACN). The base of the detection transistor (Q2) is connected to the third voltage divider resistor (R5), the emitter is grounded, and the collector is connected to the second pull-up resistor (R13). The other end of the second pull-up resistor (R13) is connected to the output terminal of the power supply module, and the collector of the detection transistor (Q2) is connected to the terminal block (CN1) for connecting to the microcontroller zero-crossing detection module of the control circuit. The power-off discharge circuit (520) includes a discharge diode (D2), the anode of which is grounded and the cathode is connected to the third voltage divider resistor (R5) and the base of the detection transistor (Q2).

7. The motor drive circuit for a soymilk maker or blender as described in claim 4, characterized in that, The power supply module includes a surge resistor (R1), a second chip (U1), an input high-voltage electrolytic capacitor (E1), an energy storage inductor (LG1), an output low-voltage electrolytic capacitor (E2), a dummy load resistor (R6), and an output high-frequency filter capacitor (C1). One end of the surge resistor (R1) is connected to the output terminal of the common mode inductor (LG2), and the other end is connected to the second chip (U1). The positive terminal of the input high-voltage electrolytic capacitor (E1) is connected to the second chip (U1), the negative terminal is connected to one end of the energy storage inductor (LG1), and the other end of the energy storage inductor (LG1) is connected to the second chip (U1). The negative terminal of the output low-voltage electrolytic capacitor (E2) is connected to the ground terminal of the second chip (U1), and the positive terminal is the output terminal of the power supply module, which is connected to the terminal block (CN1). The dummy load resistor (R6) and the output high-frequency filter capacitor (C1) are both connected in parallel with the output low-voltage electrolytic capacitor (E2).

8. The motor drive circuit for a soymilk maker or blender as described in claim 7, characterized in that, It also includes a mains voltage detection circuit (600). The mains voltage detection circuit (600) includes a fourth voltage divider resistor (R7), a fifth voltage divider resistor (R8), a sixth voltage divider resistor (R9), and a seventh voltage divider resistor (R10) connected in series, as well as a first filter capacitor (C3). One end of the fourth voltage divider resistor (R7) is connected to the second chip (U1) to introduce the voltage signal of the AC mains, and the other end of the seventh voltage divider resistor (R10) is grounded. The sixth voltage divider resistor (R9) and the seventh voltage divider resistor (R10) are connected in series to a signal output node (SYS). The signal output node (SYS) is connected to the pin in the terminal block (CN1) used for mains power detection. The first filter capacitor (C3) is connected in parallel with the seventh voltage divider resistor (R10), with one end grounded and the other end connected to the signal output node (SYS).

9. The motor drive circuit for a soymilk maker or blender as described in claim 4, characterized in that, It also includes a temperature detection and buzzer circuit (700); the temperature detection and buzzer circuit (700) includes a sensor terminal (NTC), an eighth voltage divider resistor (R11), a ninth voltage divider resistor (R12), a second filter capacitor (C2), a buzzer (BUZ1), and a DC blocking capacitor (C4); The sensor terminal (NTC) is used to connect an external temperature sensor. One end of the sensor is connected to the output terminal of the power supply module, and the other end is connected to a multiplexed circuit node (NT / B). The multiplexed circuit node (NT / B) is connected to the terminal block (CN1). The eighth voltage divider resistor (R11) is connected between the multiplexing circuit node and the sensor terminal (NTC). The ninth voltage divider resistor (R12) is connected in parallel with the second filter capacitor (C2). One end of the parallel branch is connected between the eighth voltage divider resistor (R11) and the sensor terminal (NTC), and the other end is grounded. One end of the buzzer (BUZ1) is connected in series with the DC blocking capacitor (C4), and the other end is grounded. The other end of the DC blocking capacitor (C4) is connected to the multiplexing circuit node (NT / B).

10. A motor drive control method applied in the motor drive circuit of a soymilk maker or blender as described in any one of claims 1-9, characterized in that, Includes the following steps: Status detection step: The detection circuit (400) continuously detects the on / off state of the magnetic reed switch (SW), generates and outputs a status detection signal to the microcontroller of the control circuit of the soymilk maker or blender; Safety judgment steps: The microcontroller in the control circuit determines whether the device is in an open or closed state based on the status detection signal; Drive control steps: When the microcontroller of the control circuit determines that the device is in a closed state, it outputs drive signals to the first transistor (Q3), the first chip (U2) and the second transistor (Q4) respectively to control the on and off of the first thyristor (QR1), the second thyristor (QR2) and the first relay (K2), thereby driving the motor (M2) to work. Fault-safe protection steps: When the device is opened, causing the magnetic reed switch (SW) to mechanically disconnect, the drive control circuit connected in series with the emitter of the first transistor (Q3), the output terminal of the first chip (U2), and the emitter of the second transistor (Q4) is physically cut off. All drive signals output by the control circuit fail, and the first thyristor (QR1), the second thyristor (QR2), and the first relay (K2) cannot conduct, causing the motor (M2) to stop running.

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