Single-phase brushless motor time-delay starting operation module
By using parallel Hall sensors and dead-time control units in single-phase brushless motors, the problems of difficult start-up and unstable operation are solved, achieving efficient, stable, and low-cost control of the motor.
Patent Information
- Application Number
- CN202520494354.X
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2025-03-20
- Publication Date
- 2026-02-24
- Estimated Expiration
- 2035-03-20
AI Technical Summary
Single-phase brushless motors with equal pole pitch suffer from problems such as difficulty in starting, vibration, unstable speed, and untimely commutation during startup and operation. Existing control schemes are complex and costly.
It employs two parallel 41F Hall sensors and a shared pull-up resistor, along with a dead-time control unit, to accurately detect the rotor position and control the on and off of the H-bridge power transistors, thereby achieving delayed start-up and stable operation.
It improves the motor's starting success rate and operational stability, reduces motor vibration and energy loss, simplifies circuit design, and lowers costs.
Smart Images
Figure CN223942610U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of motor control technology, specifically to a delayed start-up module for a single-phase brushless motor, which aims to achieve precise control over the start-up and operation process of a single-phase equal-pole-pitch brushless motor, thereby improving motor performance and stability. Background Technology
[0002] In modern industrial production and daily life, electric motors, as key devices for converting electrical energy into mechanical energy, are widely used. Compared with traditional brushed motors, brushless motors have significant advantages such as high efficiency, energy saving, low noise, and long lifespan, and are therefore gradually replacing brushed motors as the mainstream choice in many fields. Among them, single-phase equal-pitch brushless motors, with their unique structure and performance characteristics, have been applied in scenarios with specific requirements for motor size, cost, and operating characteristics, such as small household appliances and power tools.
[0003] However, single-phase equal-pitch brushless motors face numerous challenges during startup and operation. Due to their structural characteristics, they are prone to starting difficulties, vibrations, or even failure to start in the initial stages. This is because, at the moment of startup, the motor needs to overcome the rotor's inertia and the static friction between the stator and rotor, and traditional control methods struggle to accurately provide the appropriate starting torque. Simultaneously, achieving smooth speed control and efficient commutation during motor operation, while avoiding current surges and efficiency reductions caused by improper commutation, is also a pressing issue that needs to be addressed.
[0004] In existing single-phase equal-pitch brushless motor control schemes, some simple Hall sensors are used for rotor position detection and commutation control. However, single Hall sensors have shortcomings in detection accuracy and response speed, failing to meet the precise control requirements of motors under complex operating conditions. For example, during motor startup, a single Hall sensor may fail to accurately capture the initial rotor position, leading to startup failure; during high-speed motor operation, the lag in its detection signal may cause untimely commutation, thus affecting motor performance and stability. Furthermore, while some complex control schemes can improve motor startup and running performance to some extent, they often require complex circuit designs and expensive control chips, increasing manufacturing costs and maintenance difficulty, hindering large-scale application.
[0005] In conclusion, developing a control module that is simple in structure, low in cost, and can effectively improve the starting and running performance of a single-phase equal-pitch brushless motor is of great practical significance and market demand. Utility Model Content
[0006] The present invention aims to solve the above-mentioned technical problems by providing a delayed start-up module for a single-phase brushless motor.
[0007] To solve the above-mentioned technical problems, the technical solution provided by this utility model is as follows: a single-phase brushless motor delayed start-up module, including a brushless motor, specifically including a rotor, a rotor main shaft, a rotor permanent magnet, and a stator. The rotor is mounted on the rotor main shaft, the rotor permanent magnet is mounted on the rotor, and the stator is installed inside the brushless motor. It also includes:
[0008] Two 41F type Hall sensors are connected in parallel, namely the first Hall sensor and the second Hall sensor;
[0009] The shared pull-up resistor has a resistance of 3300Ω. One end of it is connected to the positive terminal of the DC power supply, and the other end is connected to the signal output terminals of the two Hall sensors respectively.
[0010] The first Hall sensor and the second Hall sensor are symmetrically installed on both sides of the geometric center line of the stator magnetic poles, with their detection surfaces facing the rotor permanent magnet.
[0011] The signal output terminals of the first Hall sensor and the second Hall sensor are connected to the control terminal of the H-bridge power transistor, and the power supply status of the stator coil is controlled by switching between high and low levels.
[0012] In addition, the single-phase brushless motor delayed start operation module proposed above according to this utility model may also have the following additional technical features:
[0013] The installation positions of the first Hall sensor and the second Hall sensor correspond to the rotor permanent magnet in the following way:
[0014] When the rotor's S pole covers any Hall sensor, its signal output terminal outputs a low level.
[0015] When the rotor's N pole completely covers both Hall sensors, its signal output terminal outputs a high level.
[0016] Furthermore, the Hall sensors are arranged according to the principle of turning off first and then on, so that during rotor rotation:
[0017] The first Hall sensor is triggered to shut down the H-bridge power transistor when the S-pole is covered;
[0018] The H-bridge power transistor is turned on when the second Hall sensor is completely covered by the N pole.
[0019] Furthermore, the signal output terminal of the Hall sensor is connected to the stator pole shoe via a terminal block;
[0020] The negative terminal of the pull-up resistor is connected to the terminal block.
[0021] Furthermore, the stator pole shoe is provided with a convex edge and a concave edge, and its geometry forms a predetermined air gap with the magnetic pole center of the rotor permanent magnet. The air gap spacing is smaller than the magnetic induction distance of the Hall sensor.
[0022] Furthermore, the magnetic pole boundary line of the rotor permanent magnet forms a mechanical bias angle of 15-30 degrees with the center line of the stator magnetic pole, which corresponds to the response delay time of the Hall sensor.
[0023] Furthermore, it also includes a dead-time control unit, which generates a power transistor switching delay of 0.5-2ms based on the difference in output signals from the two Hall sensors, ensuring that the H-bridge power transistors do not experience shoot-through short circuits.
[0024] The advantages of this utility model compared with the prior art are as follows:
[0025] 1. Improved startup performance
[0026] Precise Start-up Control: Through the parallel configuration of two 41F Hall effect sensors and their unique installation position, the initial position and rotation direction of the rotor can be detected more accurately. At startup, a suitable start-up signal can be quickly and accurately provided to the motor, effectively overcoming the starting difficulties of single-phase equal-pitch brushless motors and significantly improving the motor's start-up success rate.
[0027] 2. Smooth Start-up Transition: The two Hall sensors are arranged according to the principle of turning off first and then on, which makes the torque output of the motor more stable during the start-up process. This avoids motor vibration caused by sudden changes in starting torque, improves the stability of the motor start-up process, and lays a good foundation for the normal operation of the motor.
[0028] 3. High-efficiency commutation control: Based on the detection results of the rotor magnetic poles by the Hall sensor, the on and off of the H-bridge power transistors can be precisely controlled to achieve accurate commutation of the stator coils. This not only improves the operating efficiency of the motor but also avoids energy loss and motor overheating problems caused by untimely or improper commutation.
[0029] 4. Enhanced Speed Stability: The dead-time control unit effectively avoids the shoot-through and short-circuit phenomenon of the H-bridge power transistors, ensuring current stability during motor operation. This results in smaller speed fluctuations and maintains stable speed output under different load conditions.
[0030] 5. Simplified Circuit Design: This invention achieves efficient control of a single-phase equal-pitch brushless motor using only two Hall sensors and a shared pull-up resistor, along with simple connection lines and a control unit. Compared to some complex control schemes, it eliminates the need for expensive control chips and complex circuit layouts, greatly simplifying circuit design and reducing hardware costs.
[0031] 5. Easy to maintain and promote: The simple structure and circuit design significantly reduce the difficulty of maintaining this module. In practical applications, once a fault occurs, it can be quickly located and resolved, reducing equipment downtime. At the same time, the lower cost also makes this module easier to promote and apply on a large scale in the market, giving it broad market prospects. Attached Figure Description
[0032] Figure 1 This is a structural schematic diagram of a single-phase brushless motor delayed start-up module according to this utility model.
[0033] Figure 2 This is a structural schematic diagram of a single-phase brushless motor delayed start-up module according to this utility model.
[0034] As shown in the figure: 1. First Hall sensor; 2. Second Hall sensor; 3. Pull-up resistor; 4. Stator pole shoe; 401. Convex edge; 402. Concave edge; 5. Stator magnetic pole geometric center line; 6. Dead time control unit; 11. Rotor; 12. Rotor main shaft; 13. Rotor permanent magnet; 14. Stator. Detailed Implementation
[0035] To make the technical problems, technical solutions, and beneficial effects of this utility model clearer, the present utility model will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the present utility model and are not intended to limit the present utility model.
[0036] I. Working principle of this utility model:
[0037] This invention relates to a delayed start-up module for a single-phase brushless motor, primarily composed of a brushless motor body and corresponding control components. The brushless motor body includes conventional components such as a rotor, rotor shaft, rotor permanent magnet, and stator. Key control components include two parallel-connected 41F-type Hall sensors (a first Hall sensor and a second Hall sensor), a shared pull-up resistor, and related connection lines and a control unit. The two Hall sensors are symmetrically mounted on either side of the stator magnetic pole geometric center line, with their detection surfaces facing the rotor permanent magnet. The pull-up resistor has a resistance of 3300Ω, with one end connected to the positive terminal of the DC power supply and the other end connected to the signal output terminals of the two Hall sensors. The signal output terminals of the Hall sensors are connected to the control terminals of the H-bridge power transistors, precisely controlling the power supply state of the stator coils by switching between high and low output levels, thereby achieving effective control of motor start-up and operation.
[0038] Hall sensor working mechanism: The 41F type Hall sensor has unique characteristics. When the side with the markings is close to the S pole of the rotor magnet, the third signal output angle of the Hall sensor is connected to the negative terminal of the second angle, and the third angle of the Hall sensor outputs a low level of approximately 0 volts. As the rotor rotates, when the N pole of the rotor magnet is close to the side with the markings on the second Hall sensor, the negative terminals of the second angle of the Hall sensor are disconnected from the triangular signal output. Because the signal line is connected in series with a pull-up resistor, after being disconnected from the negative terminal, the positive voltage output of the triangular band of the Hall sensor is high. In this module, two Hall sensors are connected in parallel and installed side by side on the geometric center line of the stator magnetic poles. When they are close to the rotor magnetic poles, they will sense the rotor magnetic poles sequentially according to the direction of rotor rotation.
[0039] Motor starting and operation control principle: During the motor starting phase, when the rotor rotates and the first Hall sensor approaches the rotor's S pole, its second and third terminals conduct, resulting in a low-level signal output. Since this signal is connected to the H-bridge power transistor, the low level causes the H-bridge power transistor to shut off the power supply to the stator coil. Simultaneously, although the rotor's magnetic pole approaches another single-phase brushless motor starting and running module, another Hall sensor remains covered by the rotor magnet's S pole, with its second and third terminals still conducting. Because the output signals of the two Hall sensors are connected in parallel, as long as one Hall sensor outputs a low level, the overall output remains low, and the H-bridge power transistor remains off. As the rotor continues to rotate past a predetermined angle and enters the stator dead zone, the rotor magnet's N pole completely covers the second Hall sensor. The signal output third terminal of the second Hall sensor is disconnected from the negative power supply's second terminal, resulting in a high-level signal output. This high level triggers the external H-bridge power transistor to conduct, thereby commutating and energizing the stator coil. In the subsequent process, the S pole of the rotor magnet will turn off the first Hall sensor and make it continue to output a low level, so that pins 1 and 4 of the H-bridge power transistor must remain at a low level. This cycle continues, and the motor can continue to operate normally.
[0040] Dead-time control principle: This invention also includes a dead-time control unit, which generates a power transistor switching delay of 0.5-2ms based on the difference in output signals from two Hall sensors. This delay is crucial, ensuring that the H-bridge power transistors do not experience shoot-through short circuits during switching. When the output signals of the two Hall sensors change, the dead-time control unit detects this difference and controls the turn-on and turn-off sequence of the H-bridge power transistors according to the preset delay time. This prevents motor damage caused by current surges during power transistor switching, effectively improving the safety and stability of motor operation.
[0041] II. Implementation Method:
[0042] Module hardware installation
[0043] First, determine two installation positions on the stator of the single-phase equal-pitch brushless motor, along both sides of the geometric center line of the stator magnetic poles. These two positions must ensure that after the first Hall sensor and the second Hall sensor are installed, their detection surfaces can accurately face the rotor permanent magnet, and the distance between them and the rotor permanent magnet is moderate. This ensures that the sensors can sensitively detect changes in the rotor magnetic poles, while avoiding damage to the sensors due to excessive proximity.
[0044] Use a dedicated sensor mounting bracket or adhesive to secure the first and second Hall sensors to their designated positions. Ensure the sensors are firmly installed and will not shift or loosen during motor operation.
[0045] Pull-up resistor installation: Solder one end of a 3300Ω pull-up resistor to the positive terminal of the DC power supply, and reliably connect the other end to the signal output terminals of the two Hall sensors via wires. During the connection process, pay attention to the soldering quality to avoid problems such as cold solder joints or short circuits.
[0046] The signal output terminal of the Hall sensor is connected to the control terminal of the H-bridge power transistor via an insulated wire. During wiring, excessive wire length and crossings with other high-voltage lines should be avoided as much as possible to reduce signal interference. The wiring route can be rationally planned according to the internal structural space of the motor, and wire clamps or wire channels can be used to secure the wires.
[0047] The negative terminal of the pull-up resistor is connected to the corresponding terminal via a wire. This terminal is used to connect to the negative terminal of the 12V DC power supply. Simultaneously, the module's signal output lines (O) are connected to terminals 1, 2, 3, and 4 of the H-bridge according to their positions, ensuring correct connections.
[0048] For the stator pole shoes, during installation, it must be ensured that their geometry, with its convex and concave edges, forms a predetermined air gap with the center of the rotor permanent magnet's pole. The air gap spacing must be strictly controlled within a range smaller than the magnetic induction distance of the Hall sensor to ensure that the Hall sensor can accurately detect changes in the rotor's magnetic poles.
[0049] Dead Time Setting: Based on the actual operating requirements of the motor, the power transistor switching delay time is set by adjusting the relevant parameters of the dead time control unit. Generally, the dead time can be set to 1ms initially, followed by motor operation testing. During the test, observe the motor's operating status, such as for current surges or motor vibration. If unstable motor operation is observed, the dead time can be appropriately increased or decreased by 0.1ms each time until the motor reaches its optimal operating state. After multiple tests and optimizations, for the single-phase equal-pitch brushless motor of this invention, the motor operates most stably when the dead time is set within the range of 0.8-1.2ms.
[0050] Offset Angle Adjustment: The mechanical offset angle formed by the magnetic pole boundary line of the rotor permanent magnet and the center line of the stator magnetic poles needs to be adjusted according to the response delay time of the Hall sensor. In actual debugging, the offset angle can be set to 20 degrees initially, then the motor can be started to observe its starting and running performance. The appropriateness of the offset angle can be determined by detecting the correspondence between the output signal of the Hall sensor and the rotor position. If difficulty in starting the motor or inaccurate commutation is found, the offset angle can be adjusted appropriately, with each adjustment increment being 2 degrees. After repeated testing and adjustment, when the offset angle is set within the range of 18-22 degrees, the motor can achieve efficient and stable starting and running.
[0051] The present invention and its embodiments have been described above. This description is not restrictive, and the accompanying drawings are only one embodiment of the present invention; the actual structure is not limited thereto. In conclusion, if those skilled in the art are inspired by this description and design similar structures and embodiments without departing from the inventive spirit of the present invention, such designs should fall within the protection scope of the present invention.
Claims
1. A single-phase brushless motor delayed start-up module, comprising a brushless motor, specifically including a rotor (11), a rotor spindle (12), a rotor permanent magnet (13), and a stator (14), wherein the rotor (11) is mounted on the rotor spindle (12), the rotor permanent magnet (13) is mounted on the rotor (11), and the stator (14) is mounted inside the brushless motor, characterized in that: Also includes: Two 41F type Hall sensors are connected in parallel, namely the first Hall sensor (1) and the second Hall sensor (2). The common pull-up resistor (3) has a resistance of 3300Ω. One end of it is connected to the positive terminal of the DC power supply, and the other end is connected to the signal output terminals of the two Hall sensors respectively. The first Hall sensor (1) and the second Hall sensor (2) are symmetrically installed on both sides of the stator magnetic pole geometric center line (5) with their detection surfaces facing the rotor permanent magnet (13). The signal output terminals of the first Hall sensor (1) and the second Hall sensor (2) are connected to the control terminals of the H-bridge power transistor, and the power supply status of the stator coil is controlled by switching between high and low levels.
2. The single-phase brushless motor delayed start-up module according to claim 1, characterized in that: The mounting positions of the first Hall sensor (1) and the second Hall sensor (2) correspond to the rotor permanent magnet (13) in the following way: When the rotor's S pole covers any Hall sensor, its signal output terminal outputs a low level. When the rotor's N pole completely covers the first and second Hall sensors, its signal output terminal outputs a high level.
3. The single-phase brushless motor delayed start-up module according to claim 1, characterized in that: The Hall sensors are arranged according to the principle of turning off first and then on, so that during the rotor rotation process: The first Hall sensor (1) is triggered to shut down the H-bridge power transistor when it is covered by the S pole; When the second Hall sensor (2) is completely covered by the N pole, it triggers the H-bridge power transistor to turn on.
4. The single-phase brushless motor delayed start-up module according to claim 1, characterized in that: The signal output terminal of the Hall sensor is connected to the stator pole shoe (4) via a terminal block. The negative terminal of the pull-up resistor (3) is connected to the terminal block.
5. A single-phase brushless motor delayed start-up module according to claim 4, characterized in that: The stator pole shoe (4) is provided with a convex edge (401) and a concave edge (402), and its geometry forms a predetermined air gap with the magnetic pole center of the rotor permanent magnet (13). The air gap spacing is smaller than the magnetic induction distance of the Hall sensor.
6. A single-phase brushless motor delayed start-up module according to claim 1, characterized in that: The magnetic pole boundary line of the rotor permanent magnet (13) forms a mechanical bias angle of 15-30 degrees with the stator magnetic pole center line (5), which corresponds to the response delay time of the Hall sensor.
7. A single-phase brushless motor delayed start-up module according to claim 1, characterized in that: It also includes a dead time control unit (6), which generates a power transistor switching delay of 0.5-2ms based on the difference in output signals of the two Hall sensors to ensure that the H-bridge power transistors do not experience shoot-through short circuits.