A control circuit for a single-phase brushless DC air-blow motor without Hall effect sensors

Abstract

This utility model belongs to the field of circuit control technology, specifically relating to a control circuit for a single-phase brushless DC air-jet motor without a Hall sensor. The main control chip IC1 is connected to the drive circuit, DC 5V input voltage, detection circuit, and speed control and feedback signal interface. The drive circuit is connected to the inverter circuit, which is connected to the DC 24V input voltage and the single-phase brushless motor. The single-phase brushless motor is connected to the detection circuit. The upper control board main control chip MCU is connected to the DC 5V input voltage, speed control and feedback signal interface, heating wire control circuit, NTC detection circuit, buzzer, digital tube and LED functional display circuit, and upper control board touch sensing circuit. This utility model solves the problems of high material and manufacturing costs, separate circuit components connected by wires, and poor compatibility in existing technologies.

Description

Technical Field

[0001] This utility model belongs to the field of circuit control technology, specifically relating to a control circuit for a single-phase brushless DC air-blow motor without a Hall sensor. Background Technology

[0002] In recent years, with the popularization of healthy eating concepts, air fryers have gradually become a popular category in the kitchen appliance market due to their characteristics of "oil-free cooking and locking in freshness and crispness." Currently, most mainstream air fryers on the market use three-phase brushless motors as their core power source. Their design logic stems from the high stability advantages of industrial-grade motors—three-phase brushless motors possess characteristics such as precise speed, balanced torque, and long lifespan, theoretically better meeting the requirements of air fryers for hot air circulation efficiency (such as continuous and stable air delivery at 200℃). However, this approach has revealed significant pain points in practical implementation.

[0003] Firstly, the cost remains high. The structure of a three-phase brushless motor is more complex than that of a traditional single-phase motor, requiring supporting drive circuits, Hall sensors, and rare-earth permanent magnets, among other materials. The cost of the motor itself alone accounts for 35%-40% of the total material cost of the machine. In addition, each functional circuit (such as the temperature control module, motor drive board, and power management unit) is designed independently and requires multiple sets of wires to connect across boards. This not only increases the process costs of PCB manufacturing, wire procurement, and manual soldering, but also leads to a decrease in yield due to the excessive number of connection nodes (according to industry data, the assembly defect rate of such solutions is about 8%-12%), further pushing up the final selling price.

[0004] Secondly, compatibility and maintainability are poor. The independent circuit design leads to significant differences in the specifications of motors, control boards, and sensors from different manufacturers. When users replace parts later, they need to match the original model; otherwise, problems such as "motor speed deviation" and "temperature control failure" are likely to occur. On the repair end, due to the lack of standardized circuit interfaces, targeted debugging is required, resulting in high repair costs and seriously affecting the user experience.

[0005] Third, energy efficiency and space utilization are limited. The discrete layout of multiple circuits forces a large amount of wiring space to be reserved inside the main unit, which compresses the volume of the heating cavity; at the same time, the heat loss of independent circuits is superimposed (such as the heat generated by the driver board), which indirectly reduces the overall energy efficiency ratio of the machine, which runs counter to the current consumer trend of "energy saving and consumption reduction".

[0006] In summary, while existing discrete circuit control solutions based on three-phase brushless motors meet basic performance requirements, they have reached a bottleneck in terms of cost, compatibility, and user experience, and urgently need to be improved through structural optimization and technological innovation. Summary of the Invention

[0007] This invention provides a control circuit and control method for a single-phase brushless DC air-blowing motor without a Hall sensor, which solves the problems of high material and manufacturing costs, independent separate circuit components, poor compatibility, etc. in the prior art.

[0008] This utility model is achieved through the following technical solution: A control circuit for a single-phase brushless DC air-blowing motor without a Hall sensor, the control circuit including a switching power supply circuit, a motor drive circuit and a host computer control circuit; the switching power supply circuit outputs DC5V voltage and DC24V voltage to the motor drive circuit and the host computer control circuit respectively. The motor drive circuit includes a main control chip IC1, a DC5V input voltage, a drive circuit, an inverter circuit, a single-phase brushless motor, a test circuit, a speed regulation and feedback signal interface, and a DC24V input voltage. The main control chip IC1 is connected to the drive circuit, DC5V input voltage, test circuit, speed regulation and feedback signal interface, respectively. The drive circuit is connected to the inverter circuit. The inverter circuit is connected to the DC24V input voltage and the single-phase brushless motor, respectively. The single-phase brushless motor is connected to the test circuit. The host computer control circuit includes an upper control board main control chip MCU, DC5V input voltage, speed regulation and feedback signal interface, heating wire control circuit, NTC detection circuit, buzzer, digital tube and LED function display, and upper control board touch sensing circuit. The main control chip MCU of the upper control board is connected to the DC5V input voltage, speed regulation and feedback signal interface, heating wire control circuit, NTC detection circuit, buzzer, digital tube and LED function display circuit and upper control board touch sensing circuit respectively.

[0009] Furthermore, the main control chip IC1 sends a signal to the drive circuit, the drive circuit sends a signal to the inverter circuit, the inverter circuit receives a DC24V input voltage and sends a signal to the single-phase brushless motor, the single-phase brushless motor sends a signal to the detection circuit, the detection circuit sends the received signal to the main control chip IC1, the main control chip IC1 also receives a DC5V input voltage signal, and the main control chip IC1 transmits signals bidirectionally with the speed regulation and feedback signal interface.

[0010] Furthermore, the main control chip MCU on the upper control board receives signals from the NTC detection circuit, the upper control board touch sensing circuit, and the DC5V input voltage. The main control chip MCU on the upper control board sends signals to the heating wire control circuit, the buzzer, the digital tube, and the LED function display. The main control chip MCU on the upper control board transmits signals bidirectionally with the speed regulation and feedback signal interface.

[0011] Furthermore, terminal 1 of the main control chip IC1 is connected to one end of capacitor C8 and the operating voltage 5V, the other end of capacitor C8 is connected to terminal 8 of the main control chip IC1, and terminal 2 of the main control chip IC1 is connected to one end of resistor R29 of the control circuit. The third terminal of the main control chip IC1 is connected to one end of the resistor R40, one end of the capacitor C11, and one end of the Zener diode ZD3 of the input PWM integrator circuit, respectively. The fifth terminal of the main control chip IC1 is connected to one end of capacitor C10, one end of resistor R21, and the fourth terminal of operational amplifier IC3 in the BLDC current amplifier circuit.

[0012] Furthermore, the driving circuit includes a resistor R29, the other end of which is connected to the base of transistor Q3. The emitter of transistor Q3 is grounded. The collector of transistor Q3 is connected to one end of resistor R24. The other end of resistor R24 ​​is connected to one end of resistor R25, one end of capacitor C7, and terminal 4 of MOSFET Q6B. The other end of resistor R25 is connected to the operating voltage 24V, the other end of capacitor C7, terminal 3 of MOSFET Q6B, terminal 3 of MOSFET Q7B, one end of resistor R26, and one end of capacitor C6. Terminal 5 of MOSFET Q6B is connected to M1 and terminal 7 of MOSFET Q6A. Terminal 2 of MOSFET Q6A is connected to one end of resistor R31 and one end of resistor R28. The other end of resistor R31 is grounded. The other end of resistor R28 is connected to terminal 7 of main control chip IC1. Terminal 1 of the field-effect transistor Q6A is connected to one end of resistor R22, one end of resistor R35, and terminal 1 of the field-effect transistor Q7A in the BLDC current amplifier circuit. The other end of resistor R35 is grounded. Terminal 2 of the field-effect transistor Q7A is connected to one end of resistor R32 and one end of resistor R33. The other end of resistor R32 is connected to terminal 6 of the main control chip IC1. The other end of resistor R33 is grounded. Terminal 7 of the field-effect transistor Q7A is connected to M2 and terminal 5 of the field-effect transistor Q7B. Terminal 4 of the field-effect transistor Q7B is connected to the other end of resistor R26, the other end of capacitor C6, and one end of resistor R27. The other end of resistor R27 is connected to the collector of transistor Q4. The emitter of transistor Q4 is also connected to terminal 2 of the main control chip IC1. The base of transistor Q4 is connected to resistor R30 and then to the operating voltage of 5V.

[0013] Furthermore, the input PWM integrator circuit includes a Zener diode ZD3. The other end of the Zener diode ZD3 is connected to the other end of capacitor C11, the emitter of transistor Q5, and one end of resistor R38. The other end of resistor R38 is connected to one end of resistor R37, one end of resistor R36, and pin 15 of the main control chip MCU on the upper control board. The other end of resistor R36 is connected to the operating voltage 5V and one end of resistor R39. The other end of resistor R39 is connected to the other end of resistor R40 and the electrode of transistor Q5.

[0014] Furthermore, the BLDC current amplification circuit includes a capacitor C10, the other end of which is grounded; the other end of resistor R21 is connected to one end of resistor R20; the other end of resistor R20 is connected to one end of resistor R19 and terminal 3 of operational amplifier IC3; a capacitor C9 is provided between terminal 1 and terminal 2 of operational amplifier IC3; and terminal 1 of operational amplifier IC3 is also connected to the other ends of resistors R22 and R23.

[0015] Furthermore, terminal 1 of the main control chip MCU on the upper control board is connected to SW1 of the touch sensing current on the upper control board through resistor R215; terminal 2 of the main control chip MCU on the upper control board is connected to SW2 of the touch sensing current on the upper control board through resistor R216; terminal 3 of the main control chip MCU on the upper control board is connected to SW3 of the touch sensing current on the upper control board through resistor R217; terminal 4 of the main control chip MCU on the upper control board is connected to SW4 of the touch sensing current on the upper control board through resistor R218; and terminal 5 of the main control chip MCU on the upper control board is connected to SW5 of the touch sensing current on the upper control board through resistor R219. The MCU main control chip on the upper control board has its pin 7 connected to the buzzer control circuit. Terminals 8, 9, 10, 11, 12, 13, 14, 16, 17, 18 and 19 of the main control chip MCU on the upper control board are all connected to the digital tube and LED functional display circuit. The MCU main control chip of the upper control board is connected to the input PWM integral circuit at terminal 15. The MCU main control chip on the upper control board has its 20th pin connected to one end of resistor R61 and one end of diode D8. The other end of resistor R61 is connected to the working voltage 5V. The other end of diode D8 is connected to one end of resistor R62 and one end of capacitor CE400. The other end of resistor R62 and the other end of capacitor CE400 are connected to ground. The 21st terminal of the main control chip MCU on the upper control board is connected to one end of capacitor C23 and one end of capacitor CE7 respectively. The 24th terminal of the main control chip MCU on the upper control board is connected to the other end of capacitor C23 and the other end of capacitor CE7 respectively, and then connected to the working voltage of 5V. The MCU main control chip on the upper control board has terminals 22, 23, 25 and 26 connected to the NTC communication interface circuit.

[0016] Furthermore, the digital tube and LED functional display circuit includes a display chip DISP1. Pin 12 of the display chip DISP1 is connected to pin 10 of the main control chip MCU on the upper control board. Pin 9 of the display chip DISP1 is connected to pin 9 of the main control chip MCU on the upper control board. Pin 8 of the display chip DISP1 is connected to pin 8 of the main control chip MCU on the upper control board. The 11th terminal of the display chip DISP1 is connected to one end of resistor R56, one end of LED207, and one end of LED214, respectively. The 7th terminal of the display chip DISP1 is connected to one end of resistor R55. The fourth terminal of the display chip DISP1 is connected to one end of resistor R54, one end of LED212, and one end of LED205, respectively. The second terminal of the display chip DISP1 is connected to one end of resistor R53, one end of LED211, and one end of LED204, respectively. Terminal 1 of the display chip DISP1 is connected to one end of resistor R52, one end of LED203, one end of LED210, and one end of LED206, respectively. The 10th terminal of the display chip DISP1 is connected to one end of resistor R51, one end of LED213, and one end of LED206, respectively. The fifth terminal of the display chip DISP1 is connected to one end of resistor R50, one end of LED201, one end of LED208, and one end of LED215, respectively.

[0017] The beneficial effects of this utility model are: This utility model features a highly integrated control circuit, including a switching power supply circuit, a motor drive circuit, and a host computer control circuit. This maximizes the utilization of the main control IC1's resources. All circuits are designed on the same PCB, resulting in a small size and high integration. This facilitates SMT and post-soldering processing, effectively reducing costs, improving compatibility, and enhancing product reliability. It also exhibits good EMC characteristics, meeting various safety certifications. Attached Figure Description

[0018] Figure 1This is a structural block diagram of the present invention.

[0019] Figure 2 This is the circuit schematic diagram of this utility model. Detailed Implementation

[0020] In the following description, specific details such as particular system architectures and techniques are set forth for illustrative purposes and not for limitation, in order to provide a thorough understanding of the embodiments of this application. However, those skilled in the art will understand that this application may also be implemented in other embodiments without these specific details. In other instances, detailed descriptions of well-known systems, apparatuses, circuits, and methods are omitted so as not to obscure the description of this application with unnecessary detail.

[0021] It should be understood that, when used in this specification and the appended claims, the term "comprising" indicates the presence of the described features, integrals, steps, operations, elements and / or components, but does not exclude the presence or addition of one or more other features, integrals, steps, operations, elements, components and / or collections thereof.

[0022] It should also be understood that the terminology used in this application specification is for the purpose of describing particular embodiments only and is not intended to limit the application. As used in this application specification and the appended claims, the singular forms “a,” “an,” and “the” are intended to include the plural forms unless the context clearly indicates otherwise.

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

[0024] Many specific details are set forth in the following description in order to provide a full understanding of this application. However, this application may also be implemented in other ways different from those described herein. Those skilled in the art can make similar extensions without departing from the spirit of this application. Therefore, this application is not limited to the specific embodiments disclosed below.

[0025] A single-phase brushless DC air fryer motor control circuit without Hall sensor, the control circuit includes a switching power supply circuit, a motor drive circuit and a host computer control circuit; the switching power supply circuit outputs DC5V voltage and DC24V voltage to the motor drive circuit and the host computer control circuit respectively. The motor drive circuit includes a main control chip IC1, a DC5V input voltage, a drive circuit, an inverter circuit, a single-phase brushless motor, a test circuit, a speed regulation and feedback signal interface, and a DC24V input voltage. The main control chip IC1 is connected to the drive circuit, DC5V input voltage, test circuit, speed regulation and feedback signal interface, respectively. The drive circuit is connected to the inverter circuit. The inverter circuit is connected to the DC24V input voltage and the single-phase brushless motor, respectively. The single-phase brushless motor is connected to the test circuit. The main control chip IC1 sends a signal to the drive circuit, the drive circuit sends a signal to the inverter circuit, the inverter circuit receives a DC24V input voltage and sends a signal to the single-phase brushless motor, the single-phase brushless motor sends a signal to the detection circuit, the detection circuit sends the received signal to the main control chip IC1, the main control chip IC1 also receives a DC5V input voltage signal, and the main control chip IC1 transmits signals bidirectionally with the speed regulation and feedback signal interface.

[0026] The host computer control circuit includes an upper control board main control chip MCU, DC5V input voltage, speed regulation and feedback signal interface, heating wire control circuit, NTC detection circuit, buzzer, digital tube and LED function display, and upper control board touch sensing circuit. The upper control board main control chip MCU receives signals from the NTC detection circuit, the upper control board touch sensing circuit and the DC5V input voltage. The upper control board main control chip MCU sends signals to the heating wire control circuit, the buzzer, the digital tube and the LED function display. The upper control board main control chip MCU transmits signals bidirectionally with the speed adjustment and feedback signal interface. The main control chip MCU of the upper control board is connected to the DC5V input voltage, speed regulation and feedback signal interface, heating wire control circuit, NTC detection circuit, buzzer, digital tube and LED function display circuit and upper control board touch sensing circuit respectively.

[0027] Furthermore, terminal 1 of the main control chip IC1 is connected to one end of capacitor C8 and the operating voltage 5V, the other end of capacitor C8 is connected to terminal 8 of the main control chip IC1, and terminal 2 of the main control chip IC1 is connected to one end of resistor R29 of the control circuit. The third terminal of the main control chip IC1 is connected to one end of the resistor R40, one end of the capacitor C11, and one end of the Zener diode ZD3 of the input PWM integrator circuit, respectively. The fifth terminal of the main control chip IC1 is connected to one end of capacitor C10, one end of resistor R21, and the fourth terminal of operational amplifier IC3 in the BLDC current amplifier circuit.

[0028] Furthermore, the driving circuit includes a resistor R29, the other end of which is connected to the base of transistor Q3. The emitter of transistor Q3 is grounded. The collector of transistor Q3 is connected to one end of resistor R24. The other end of resistor R24 ​​is connected to one end of resistor R25, one end of capacitor C7, and terminal 4 of MOSFET Q6B. The other end of resistor R25 is connected to the operating voltage 24V, the other end of capacitor C7, terminal 3 of MOSFET Q6B, terminal 3 of MOSFET Q7B, one end of resistor R26, and one end of capacitor C6. Terminal 5 of MOSFET Q6B is connected to M1 and terminal 7 of MOSFET Q6A. Terminal 2 of MOSFET Q6A is connected to one end of resistor R31 and one end of resistor R28. The other end of resistor R31 is grounded. The other end of resistor R28 is connected to terminal 7 of main control chip IC1. Terminal 1 of the field-effect transistor Q6A is connected to one end of resistor R22, one end of resistor R35, and terminal 1 of the field-effect transistor Q7A in the BLDC current amplifier circuit. The other end of resistor R35 is grounded. Terminal 2 of the field-effect transistor Q7A is connected to one end of resistor R32 and one end of resistor R33. The other end of resistor R32 is connected to terminal 6 of the main control chip IC1. The other end of resistor R33 is grounded. Terminal 7 of the field-effect transistor Q7A is connected to M2 and terminal 5 of the field-effect transistor Q7B. Terminal 4 of the field-effect transistor Q7B is connected to the other end of resistor R26, the other end of capacitor C6, and one end of resistor R27. The other end of resistor R27 is connected to the collector of transistor Q4. The emitter of transistor Q4 is also connected to terminal 2 of the main control chip IC1. The base of transistor Q4 is connected to resistor R30 and then to the operating voltage of 5V.

[0029] Furthermore, the input PWM integrator circuit includes a Zener diode ZD3. The other end of the Zener diode ZD3 is connected to the other end of capacitor C11, the emitter of transistor Q5, and one end of resistor R38. The other end of resistor R38 is connected to one end of resistor R37, one end of resistor R36, and pin 15 of the main control chip MCU on the upper control board. The other end of resistor R36 is connected to the operating voltage 5V and one end of resistor R39. The other end of resistor R39 is connected to the other end of resistor R40 and the electrode of transistor Q5.

[0030] Furthermore, the BLDC current amplification circuit includes a capacitor C10, the other end of which is grounded; the other end of resistor R21 is connected to one end of resistor R20; the other end of resistor R20 is connected to one end of resistor R19 and terminal 3 of operational amplifier IC3; a capacitor C9 is provided between terminal 1 and terminal 2 of operational amplifier IC3; and terminal 1 of operational amplifier IC3 is also connected to the other ends of resistors R22 and R23.

[0031] Furthermore, terminal 1 of the main control chip MCU on the upper control board is connected to SW1 of the touch sensing current on the upper control board through resistor R215; terminal 2 of the main control chip MCU on the upper control board is connected to SW2 of the touch sensing current on the upper control board through resistor R216; terminal 3 of the main control chip MCU on the upper control board is connected to SW3 of the touch sensing current on the upper control board through resistor R217; terminal 4 of the main control chip MCU on the upper control board is connected to SW4 of the touch sensing current on the upper control board through resistor R218; and terminal 5 of the main control chip MCU on the upper control board is connected to SW5 of the touch sensing current on the upper control board through resistor R219. The MCU main control chip on the upper control board has its pin 7 connected to the buzzer control circuit. Terminals 8, 9, 10, 11, 12, 13, 14, 16, 17, 18 and 19 of the main control chip MCU on the upper control board are all connected to the digital tube and LED functional display circuit. The MCU main control chip of the upper control board is connected to the input PWM integral circuit at terminal 15. The MCU main control chip on the upper control board has its 20th pin connected to one end of resistor R61 and one end of diode D8. The other end of resistor R61 is connected to the working voltage 5V. The other end of diode D8 is connected to one end of resistor R62 and one end of capacitor CE400. The other end of resistor R62 and the other end of capacitor CE400 are connected to ground. The 21st terminal of the main control chip MCU on the upper control board is connected to one end of capacitor C23 and one end of capacitor CE7 respectively. The 24th terminal of the main control chip MCU on the upper control board is connected to the other end of capacitor C23 and the other end of capacitor CE7 respectively, and then connected to the working voltage of 5V. The MCU main control chip on the upper control board has terminals 22, 23, 25 and 26 connected to the NTC communication interface circuit.

[0032] Furthermore, the digital tube and LED functional display circuit includes a display chip DISP1. Pin 12 of the display chip DISP1 is connected to pin 10 of the main control chip MCU on the upper control board. Pin 9 of the display chip DISP1 is connected to pin 9 of the main control chip MCU on the upper control board. Pin 8 of the display chip DISP1 is connected to pin 8 of the main control chip MCU on the upper control board. The 11th terminal of the display chip DISP1 is connected to one end of resistor R56, one end of LED207, and one end of LED214, respectively. The 7th terminal of the display chip DISP1 is connected to one end of resistor R55. The fourth terminal of the display chip DISP1 is connected to one end of resistor R54, one end of LED212, and one end of LED205, respectively. The second terminal of the display chip DISP1 is connected to one end of resistor R53, one end of LED211, and one end of LED204, respectively. Terminal 1 of the display chip DISP1 is connected to one end of resistor R52, one end of LED203, one end of LED210, and one end of LED206, respectively. The 10th terminal of the display chip DISP1 is connected to one end of resistor R51, one end of LED213, and one end of LED206, respectively. The fifth terminal of the display chip DISP1 is connected to one end of resistor R50, one end of LED201, one end of LED208, and one end of LED215, respectively.

[0033] The working principle of a single-phase brushless DC air-blow motor control circuit without Hall sensor is as follows: the switching power supply circuit includes AC-DC and DC-DC, wherein the circuit composed of U1 is the AC-DC part. The input AC voltage of 100-220V is rectified into DC 141-310V after bridge rectification. U1 is controlled by the transformer flyback, and the secondary output of the transformer is DC24V. This power supply mainly provides voltage for the operation of BLDC, and at the same time provides input power for U2 and voltage for relay control. The circuit composed of U2 is the DC-DC section, with an input voltage of DC 24V. U2 outputs DC 5V through BUCK control. This power supply mainly provides voltage for IC1, U4, as well as the supporting auxiliary circuits and intelligent control modules. The motor drive circuit adopts a sensorless drive method, which can be controlled by a sensorless square wave. IC1 is the main control unit, Q6A, Q6B, Q7A, and Q7B are power units, and R35 is a current detection unit. The host computer can input PWM and convert it to DC level through an integrator circuit. IC1 samples and identifies the signal through AD1 to realize the speed control of BLDC. IC1 can also output an FG feedback signal to the host computer through the IO port to facilitate the host computer's monitoring of BLDC.

[0034] Furthermore, the main control U4 of the host computer control circuit realizes the corresponding functions by detecting the changes in the voltage of the corresponding ports of SW1-SW5. That is, SW1 is the cooking mode selection, SW3 is a multiplex key that can select the motor speed, cooking timer and cooking temperature mode adjustment settings. After selection by SW3, the motor speed, timer and temperature are adjusted by SW2 and SW4. SW2 decreases and SW4 increases; SW5 is the power on and power off key. LEDs 201, 203, 204, 205, 206, 208, 210, 211, 212, and 213 are used to display the cooking mode of the air fryer. Each press of SW1 switches the mode, and the modes can be cycled. LEDs 202, 209, 215, and 216 are used to display the motor's operating status. When the air fryer's motor starts working, the operation status of the fan is displayed by the sequential lighting of these four LEDs. The DSP single-digit LED display shows the set motor speed, temperature, and time. CN1 is connected to an NTC resistor, and the main control U4 detects the voltage of R48. The heating wire is switched via relay JD1 to control the working temperature of the air fryer. CN2 is an expansion circuit used to configure the WIFI module or NFC module to achieve intelligent control.

[0035] This invention utilizes a single-phase design (4 / 6 / 8 stator slots), improving production efficiency during stator coil winding. Furthermore, the coil has only two terminals, contributing to increased overall production efficiency and reduced costs. While meeting market demands, it also simplifies the wiring process, requiring only positive and negative terminals, enhancing the user experience. Simultaneously, the adoption of a sensorless control method improves output stability and broadens the applicability of the design.

Claims

1. A single phase brushless DC air blast motor control circuit without Hall sensors, characterized by, The control circuit includes a switching power supply circuit, a motor drive circuit, and a host computer control circuit; the switching power supply circuit outputs DC5V voltage and DC24V voltage to the motor drive circuit and the host computer control circuit, respectively. The motor drive circuit includes a main control chip IC1, a DC5V input voltage, a drive circuit, an inverter circuit, a single-phase brushless motor, a test circuit, a speed regulation and feedback signal interface, and a DC24V input voltage. The main control chip IC1 is connected to the drive circuit, DC5V input voltage, test circuit, speed regulation and feedback signal interface, respectively. The drive circuit is connected to the inverter circuit. The inverter circuit is connected to the DC24V input voltage and the single-phase brushless motor, respectively. The single-phase brushless motor is connected to the test circuit. The host computer control circuit includes an upper control board main control chip MCU, DC5V input voltage, speed regulation and feedback signal interface, heating wire control circuit, NTC detection circuit, buzzer, digital tube and LED function display, and upper control board touch sensing circuit. The main control chip MCU of the upper control board is connected to the DC5V input voltage, speed regulation and feedback signal interface, heating wire control circuit, NTC detection circuit, buzzer, digital tube and LED function display circuit and upper control board touch sensing circuit respectively.

2. The single-phase brushless DC air-blow motor control circuit without a Hall sensor according to claim 1, characterized in that, The main control chip IC1 sends a signal to the drive circuit, the drive circuit sends a signal to the inverter circuit, the inverter circuit receives a DC24V input voltage and sends a signal to the single-phase brushless motor, the single-phase brushless motor sends a signal to the detection circuit, the detection circuit sends the received signal to the main control chip IC1, the main control chip IC1 also receives a DC5V input voltage signal, and the main control chip IC1 transmits signals bidirectionally with the speed regulation and feedback signal interface.

3. The Hall sensorless single phase brushless DC airblast motor control circuit of claim 1, wherein, The upper control board main control chip MCU receives signals from the NTC detection circuit, the upper control board touch sensing circuit, and the DC5V input voltage. The upper control board main control chip MCU sends signals to the heating wire control circuit, the buzzer, the digital tube, and the LED function display. The upper control board main control chip MCU transmits signals bidirectionally with the speed adjustment and feedback signal interface.

4. The Hall sensorless single phase brushless DC airblast motor control circuit of claim 1, wherein, Terminal 1 of the main control chip IC1 is connected to one end of capacitor C8 and the working voltage 5V, the other end of capacitor C8 is connected to terminal 8 of the main control chip IC1, and terminal 2 of the main control chip IC1 is connected to one end of resistor R29 of the control circuit. The third terminal of the main control chip IC1 is connected to one end of the resistor R40, one end of the capacitor C11, and one end of the Zener diode ZD3 of the input PWM integrator circuit, respectively. The fifth terminal of the main control chip IC1 is connected to one end of capacitor C10, one end of resistor R21, and the fourth terminal of operational amplifier IC3 in the BLDC current amplifier circuit.

5. The Hall sensorless single phase brushless DC airblast motor control circuit of claim 1, wherein, The driving circuit includes a resistor R29. The other end of the resistor R29 is connected to the base of transistor Q3. The emitter of transistor Q3 is grounded. The collector of transistor Q3 is connected to one end of resistor R24. The other end of resistor R24 ​​is connected to one end of resistor R25, one end of capacitor C7, and terminal 4 of MOSFET Q6B. The other end of resistor R25 is connected to the operating voltage 24V, the other end of capacitor C7, terminal 3 of MOSFET Q6B, terminal 3 of MOSFET Q7B, one end of resistor R26, and one end of capacitor C6. Terminal 5 of MOSFET Q6B is connected to M1 and terminal 7 of MOSFET Q6A. Terminal 2 of MOSFET Q6A is connected to one end of resistor R31 and one end of resistor R28. The other end of resistor R31 is grounded. The other end of resistor R28 is connected to terminal 7 of main control chip IC1. Terminal 1 of the field-effect transistor Q6A is connected to one end of resistor R22, one end of resistor R35, and terminal 1 of the field-effect transistor Q7A in the BLDC current amplifier circuit. The other end of resistor R35 is grounded. Terminal 2 of the field-effect transistor Q7A is connected to one end of resistor R32 and one end of resistor R33. The other end of resistor R32 is connected to terminal 6 of the main control chip IC1. The other end of resistor R33 is grounded. Terminal 7 of the field-effect transistor Q7A is connected to M2 and terminal 5 of the field-effect transistor Q7B. Terminal 4 of the field-effect transistor Q7B is connected to the other end of resistor R26, the other end of capacitor C6, and one end of resistor R27. The other end of resistor R27 is connected to the collector of transistor Q4. The emitter of transistor Q4 is also connected to terminal 2 of the main control chip IC1. The base of transistor Q4 is connected to resistor R30 and then to the operating voltage of 5V.

6. The Hall sensorless single phase brushless DC airblast motor control circuit of claim 4, wherein, The input PWM integrator circuit includes a Zener diode ZD3. The other end of the Zener diode ZD3 is connected to the other end of capacitor C11, the emitter of transistor Q5, and one end of resistor R38. The other end of resistor R38 is connected to one end of resistor R37, one end of resistor R36, and pin 15 of the main control chip MCU on the upper control board. The other end of resistor R36 is connected to the operating voltage 5V and one end of resistor R39. The other end of resistor R39 is connected to the other end of resistor R40 and the electrode of transistor Q5.

7. The Hall sensorless single phase brushless DC airblast motor control circuit according to claim 4, wherein, The BLDC current amplifier circuit includes a capacitor C10, the other end of which is grounded. The other end of a resistor R21 is connected to one end of a resistor R20. The other end of a resistor R20 is connected to one end of a resistor R19 and pin 3 of an operational amplifier IC3. A capacitor C9 is provided between pin 1 and pin 2 of an operational amplifier IC3. Pin 1 of an operational amplifier IC3 is also connected to the other ends of resistors R22 and R23.

8. The Hall sensorless single phase brushless DC airblast motor control circuit of claim 1, wherein, Terminal 1 of the main control chip MCU on the upper control board is connected to SW1 of the touch sensing current on the upper control board through resistor R215; terminal 2 of the main control chip MCU on the upper control board is connected to SW2 of the touch sensing current on the upper control board through resistor R216; terminal 3 of the main control chip MCU on the upper control board is connected to SW3 of the touch sensing current on the upper control board through resistor R217; terminal 4 of the main control chip MCU on the upper control board is connected to SW4 of the touch sensing current on the upper control board through resistor R218; and terminal 5 of the main control chip MCU on the upper control board is connected to SW5 of the touch sensing current on the upper control board through resistor R219. The MCU main control chip on the upper control board has its pin 7 connected to the buzzer control circuit. Terminals 8, 9, 10, 11, 12, 13, 14, 16, 17, 18 and 19 of the main control chip MCU on the upper control board are all connected to the digital tube and LED functional display circuit. The MCU main control chip of the upper control board is connected to the input PWM integral circuit at terminal 15. The MCU main control chip on the upper control board has its 20th pin connected to one end of resistor R61 and one end of diode D8. The other end of resistor R61 is connected to the working voltage 5V. The other end of diode D8 is connected to one end of resistor R62 and one end of capacitor CE400. The other end of resistor R62 and the other end of capacitor CE400 are connected to ground. The 21st terminal of the main control chip MCU on the upper control board is connected to one end of capacitor C23 and one end of capacitor CE7 respectively. The 24th terminal of the main control chip MCU on the upper control board is connected to the other end of capacitor C23 and the other end of capacitor CE7 respectively, and then connected to the working voltage of 5V. The MCU main control chip on the upper control board has terminals 22, 23, 25 and 26 connected to the NTC communication interface circuit.

9. The Hall sensorless single-phase brushless DC airblast motor control circuit of claim 8, wherein, The digital tube and LED display circuit includes a display chip DISP1. Pin 12 of the display chip DISP1 is connected to pin 10 of the main control chip MCU on the upper control board. Pin 9 of the display chip DISP1 is connected to pin 9 of the main control chip MCU on the upper control board. Pin 8 of the display chip DISP1 is connected to pin 8 of the main control chip MCU on the upper control board. The 11th terminal of the display chip DISP1 is connected to one end of resistor R56, one end of LED207, and one end of LED214, respectively. The 7th terminal of the display chip DISP1 is connected to one end of resistor R55. The fourth terminal of the display chip DISP1 is connected to one end of resistor R54, one end of LED212, and one end of LED205, respectively. The second terminal of the display chip DISP1 is connected to one end of resistor R53, one end of LED211, and one end of LED204, respectively. Terminal 1 of the display chip DISP1 is connected to one end of resistor R52, one end of LED203, one end of LED210, and one end of LED206, respectively. The 10th terminal of the display chip DISP1 is connected to one end of resistor R51, one end of LED213, and one end of LED206, respectively. The fifth terminal of the display chip DISP1 is connected to one end of resistor R50, one end of LED201, one end of LED208, and one end of LED215, respectively.

Images