Control method and control system of single-phase alternating-current permanent magnet synchronous motor

Abstract

The invention discloses a control method and a control system of a single-phase alternating-current permanent magnet synchronous motor. The control method of the single-phase alternating-current permanent magnet synchronous motor comprises the following steps: acquiring magnetic pole position information of a motor rotor; acquiring period information of an alternating current power supply; supplying power to the first winding and the second winding in the positive half cycle or the negative half cycle of the alternating current power supply according to the rotor magnetic pole position information and the alternating current power supply cycle information, and determining the connection mode of the first end and the second end with the alternating current power supply; power supply is cut off in a preset time before zero crossing of the AC power supply, and the power supply is switched on again after zero crossing of the next power supply period. A corresponding relation between a magnetic pole position and an alternating-current power supply period is established by acquiring motor rotor magnetic pole position information and alternating-current power supply period information, and a connection mode between a first end and an alternating-current power supply and a second end and the alternating-current power supply is optimized according to a selective power supply strategy of a positive half period or a negative half period of the alternating-current power supply and a rotor position. And first-step commutation control based on the magnetic pole position is formed.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of motor control, in particular to a control method and control system of a single-phase alternating current permanent magnet synchronous motor. BACKGROUND

[0002] Permanent magnet synchronous motor and brushless direct current motor are widely used in modern industry as motor types, and their working principle is based on the interaction of the rotating magnetic field generated by the stator winding and the permanent magnet rotor magnetic field. In order to realize the continuous and stable operation of the motor, it is necessary to adjust the energization timing of the stator winding in real time according to the rotor position, that is, to carry out commutation control, so that the stator magnetic field always maintains a proper phase relationship with the rotor magnetic field, thereby generating continuous driving torque and controlling the rotation direction of the rotor.

[0003] In the prior art, in order to realize the commutation driving and direction control of the motor, a real-time control scheme based on electronic microcontroller is generally used. This scheme detects the rotor position through a position sensor (such as a Hall sensor or an encoder), and the microcontroller calculates the corresponding commutation timing according to the position feedback signal, and controls the on-off of each phase winding through power switching devices (such as MOSFET or IGBT), to realize accurate control of the stator magnetic field. This electronic commutation technology can effectively control the direction of the motor, and has been widely used abroad.

[0004] However, the existing electronic micro-control commutation technology has obvious technical defects. First, due to the on-voltage drop and switching loss of the power switching device, as well as the power consumption of the control circuit itself, the overall system efficiency is low, and second, the traditional square wave driving method produces large torque ripple and harmonic loss, further reducing the efficiency of the motor. SUMMARY

[0005] The main purpose of the present application is to provide a control method for a single-phase alternating current permanent magnet synchronous motor, which aims to solve the problem of low efficiency of the existing electronic micro-control commutation.

[0006] To achieve the above purpose, the present application provides a control method for a single-phase alternating current permanent magnet synchronous motor, the single-phase alternating current permanent magnet synchronous motor comprising a rotor and a stator, the stator comprising a first winding and a second winding connected in series, the first winding having a first end, and the second winding having a second end, the control method comprising: obtaining rotor magnetic pole position information; obtaining cycle information of an alternating current power supply; According to the rotor magnetic pole position information and the alternating current power supply cycle information, the first winding and the second winding are powered in the positive half cycle or the negative half cycle of the alternating current power supply, and the connection mode of the first end and the second end with the alternating current power supply is determined; The power supply is disconnected at a preset time before the zero-crossing point of the AC power supply, and the power supply is reconnected after the zero-crossing point of the next power supply cycle.

[0007] In some embodiments, the method further comprises: determining a preset detection position; supplying power to the first winding and the second winding during the positive half cycle of the AC power supply when the first magnetic pole of the rotor is at the preset detection position; supplying power to the first winding and the second winding during the negative half cycle of the AC power supply when the second magnetic pole of the rotor is at the preset detection position; wherein the first magnetic pole and the second magnetic pole have opposite polarities, and the first end and the second end have different connection modes with the AC power supply; In some embodiments, the method further comprises: connecting the first end of the first winding to the phase line of the AC power supply and connecting the second end of the second winding to the neutral line of the AC power supply when the first magnetic pole is at the preset detection position; connecting the second end of the second winding to the phase line of the AC power supply and connecting the first end of the first winding to the neutral line of the AC power supply when the second magnetic pole is at the preset detection position.

[0008] In some embodiments, the single-phase AC permanent magnet synchronous motor further comprises a Hall sensor, and the preset detection position is the installation position of the Hall sensor.

[0009] In some embodiments, the method further comprises: T / 20≤t≤T / 5.

[0010] In some embodiments, the method further comprises: when the preset time t is 1 / 10 of the half cycle time of the AC power supply, the ratio η of the voltage integral value of the actual power supply section to the voltage integral value of the complete half cycle satisfies: η = 1.95 / 2 = 97.5%.

[0011] In some embodiments, the control method of the single-phase AC permanent magnet synchronous motor further comprises: Determine whether the rotor magnetic pole position and AC power cycle meet the preset power supply conditions; When the power supply conditions are met, power is supplied to the first winding and the second winding; When the power supply conditions are not met, the power supply is disconnected, and the process continues to judge in the subsequent half-cycle. When the power supply conditions are met again, the power supply is restored.

[0012] In some embodiments, determining whether the rotor magnetic pole position and AC power cycle meet the preset power supply conditions includes: if the rotor corresponding magnetic pole has not yet reached the preset detection position when the expected half-cycle of power supply arrives, the power is disconnected and the power is re-energized after the rotor magnetic pole rotates to the preset detection position.

[0013] In some embodiments, determining whether the rotor magnetic pole position and AC power cycle meet the preset power supply conditions includes: if the rotor corresponding magnetic pole exceeds the preset detection position when the expected half-cycle of power supply arrives, the power is disconnected and the power is re-energized after the rotor magnetic pole reaches the preset detection position again.

[0014] This invention further proposes a control system for a single-phase AC permanent magnet synchronous motor, comprising: A single-phase AC permanent magnet synchronous motor, the single-phase AC permanent magnet synchronous motor including a rotor and a stator, the stator including a first winding and a second winding connected in series; A Hall sensor is disposed inside the end cover of the single-phase AC permanent magnet synchronous motor to detect the magnetic pole position of the rotor. A zero-crossing detection module is used to detect the zero-crossing point of the AC power supply and to obtain the period information of the AC power supply. A power supply switching device is provided, which is electrically connected to the first winding, the second winding and the AC power supply respectively, so as to control the connection mode of the first winding and the second winding with the AC power supply. The controller is electrically connected to the Hall sensor, the zero-crossing detection module, and the power supply switching device, and is used to execute the control method of the single-phase AC permanent magnet synchronous motor in the aforementioned embodiment.

[0015] The beneficial effects of the technical solution of this invention are as follows: By acquiring the rotor magnetic pole position information and AC power cycle information, a correspondence between the magnetic pole position and the AC power cycle is established. Combined with the selective power supply strategy during the positive or negative half-cycle of the AC power supply and the optimization of the connection method between the first and second terminals and the AC power supply according to the rotor position, a first-step commutation control based on the magnetic pole position is formed. At the same time, by disconnecting the power supply for a preset time before the AC power supply crosses zero and reconnecting it after the zero-crossing point of the next power supply cycle, a second-step commutation control based on the power cycle is formed. This two-step commutation mechanism realizes the phase matching between the stator magnetic field and the permanent magnet rotor magnetic field, avoids the reverse torque and invalid current caused by phase mismatch in traditional control methods, and eliminates the invalid power consumption and switching losses during the voltage zero crossing period, and reduces the copper loss and iron loss caused by harmonic current, thereby significantly improving the overall operating efficiency of the single-phase AC permanent magnet synchronous motor. Attached Figure Description

[0016] Figure 1 This is a flowchart illustrating an embodiment of the control method for a single-phase AC permanent magnet synchronous motor according to the present invention. Figure 2 This is a flowchart illustrating an embodiment of the control method for a single-phase AC permanent magnet synchronous motor according to the present invention. Figure 3 This is a flowchart illustrating another embodiment of the control method for a single-phase AC permanent magnet synchronous motor of the present invention; Figure 4 This is a flowchart illustrating another embodiment of the control method for a single-phase AC permanent magnet synchronous motor according to the present invention.

[0017] The realization of the objective, functional features and advantages of the present invention will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0018] The solutions in the embodiments of the present invention 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 the present invention, and not all of them. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0019] It should be noted that all directional indications (such as up, down, left, right, front, back, etc.) in the embodiments of the present invention are only used to explain the relative positional relationship and movement of each component in a certain specific posture (as shown in the figure). If the specific posture changes, the directional indication will also change accordingly.

[0020] It should also be noted that when a component is described as "fixed to" or "set on" another component, it can be directly on the other component or there may be an intervening component present. When a component is described as "connected to" another component, it can be directly connected to the other component or there may be an intervening component present.

[0021] Furthermore, the use of terms such as "first" and "second" in this invention is for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined with "first" or "second" may explicitly or implicitly include at least one of that feature. Additionally, the technical solutions of the various embodiments can be combined with each other, but only on the basis of being achievable by those skilled in the art. When the combination of technical solutions is contradictory or impossible to implement, such a combination of technical solutions should be considered non-existent and not within the scope of protection claimed by this invention.

[0022] Reference Figure 1 This invention proposes a control method for a single-phase AC permanent magnet synchronous motor. The single-phase AC permanent magnet synchronous motor includes a rotor and a stator. The stator includes a first winding and a second winding connected in series. The first winding has a first end, and the second winding has a second end. The control method for the single-phase AC permanent magnet synchronous motor includes: Step S10: Obtain the position information of the motor rotor magnetic poles; Step S20: Obtain the cycle information of the AC power supply; Step S30: Based on the rotor magnetic pole position information and AC power supply cycle information, supply power to the first winding and the second winding during the positive or negative half-cycle of the AC power supply, and determine the connection method between the first end and the second end and the AC power supply. Step S40: Disconnect the power supply at a preset time before the AC power supply crosses zero, and reconnect the power supply after the zero-crossing point of the next power supply cycle.

[0023] The control method for the single-phase AC permanent magnet synchronous motor in this embodiment is mainly used to perform a two-step commutation operation on the single-phase AC permanent magnet synchronous motor. This two-step commutation mechanism realizes the phase matching between the stator magnetic field and the permanent magnet rotor magnetic field, avoids the reverse torque and invalid current caused by phase mismatch in the traditional control method, and eliminates the invalid power consumption and switching loss during the voltage zero crossing period. It also reduces the copper loss and iron loss caused by harmonic current, thereby significantly improving the overall operating efficiency of the single-phase AC permanent magnet synchronous motor.

[0024] Specifically, the rotor magnetic pole position information can be obtained in various ways. Preferably, Hall sensor detection is used. The Hall sensor is electrically connected to the main controller. For example, taking the motor magnetic poles as N and S poles, when a positive magnetic field N pole passes through the Hall sensor, the Hall sensor outputs a high level "1" and when a reverse magnetic field S pole passes through the Hall sensor, it outputs a low level "0". In this way, real-time rotor magnetic pole position information can be obtained. Alternatively, a photoelectric encoder, a rotary transformer, or a sensorless back EMF detection method can also be used to obtain rotor position information.

[0025] There are multiple ways to obtain AC power supply cycle information. One approach is to use a zero-crossing detection circuit to detect the zero-crossing point of the AC voltage and output a pulse signal through a comparator. Another approach is to use a voltage sampling circuit combined with an analog-to-digital converter (ADC) to sample and analyze the AC voltage waveform in real time. A phase-locked loop (PLL) circuit can be used to lock the power supply frequency and generate a synchronization signal. Alternatively, an optocoupler-isolated AC signal shaping circuit can be used to convert the sine wave into a square wave signal for the main controller to identify the cycle characteristics.

[0026] After obtaining the rotor's magnetic pole position information and the cycle information of the single-phase AC power supply, the stator of the motor can be powered at the appropriate time based on the matching relationship between the two information. For example, when the Hall sensor detects that the negative magnetic field S pole is passing by (Hall output "0"), the control system determines that power should be supplied during the negative half-cycle of the single-phase AC power. At this time, the second end of the second winding is connected to the phase line (L line) of the single-phase AC power through power switching devices (such as bidirectional thyristors, relays, contactors, or IGBT modules), and the first end of the first winding is connected to the neutral line (N line). The current path is then: phase line, second end, second winding, first winding, first end, neutral line, forming a complete current loop. Under this configuration, the second winding generates a positive magnetic field (N pole), which attracts the rotor's S pole and pulls the rotor forward; the first winding generates a negative magnetic field (S pole), which repels the rotor's S pole and pushes the rotor forward, while simultaneously attracting the rotor's N pole, forming a continuous and stable positive driving torque.

[0027] As the motor rotor continues to rotate until nearly half a rotor cycle, the power supply is disconnected at a preset time before the AC power crosses zero. This preset time is, for example, t milliseconds (where t = T / 10, T is the half-cycle time of the AC power; for example, for a 50Hz power supply, T = 10ms, then t = 1ms). Precise control of the power-off timing can avoid ineffective conduction losses when the voltage is low near the zero-crossing point. When the next cycle arrives, the power supply is restored after the zero-crossing point. At this time, when the motor rotor has rotated approximately 180 mechanical angles, the positive magnetic field N pole passes through the Hall sensor (Hall output "1"), and at the same time, it is detected that the single-phase AC power has reached the positive half-cycle. The control system switches the power supply mode accordingly: the first end of the first winding is connected to the phase line (L line) of the single-phase AC power through the power switching device, and the second end of the second winding is connected to the neutral line (N line). The current path at this time is as follows: phase line, first end, first winding, second winding, second end, neutral line, forming a loop. In this configuration, the first winding generates a positive magnetic field (N pole), which repels the N pole of the rotor and propels the rotor forward, while simultaneously attracting the S pole of the rotor; the second winding generates a negative magnetic field (S pole), which attracts the N pole of the rotor and pulls the rotor forward, while simultaneously repelling the S pole of the rotor, thus forming a continuous and stable positive driving torque. This cycle repeats to achieve continuous and stable operation of the motor.

[0028] The complete working process of the control method of the present invention is described in detail below with reference to specific working sequences: In the initial state, after the system is powered on, the main controller first initializes all power switching devices to the off state, and simultaneously starts the rotor position detection and power cycle detection modules. Assuming that at the initial time t0, the Hall sensor detects that the rotor's S pole has passed (outputs "0"), and at the same time, the AC power supply is in the negative half-cycle (the voltage is negative), the first commutation condition is met. The main controller outputs a control signal to activate the power switching devices, connecting the second terminal to the phase line L and the first terminal to the neutral line N, thus starting to supply power to the motor.

[0029] During the time interval from t0 to t1 (approximately half an AC cycle minus the preset power-off time, i.e., Tt), current flows from the phase line through the second winding and the first winding to the neutral line. The positive magnetic field (N pole) generated by the second winding attracts the rotor's (S pole), while the negative magnetic field (S pole) generated by the first winding repels the rotor's (S pole). The combined magnetic fields of the two windings generate a strong positive driving torque, propelling the rotor to accelerate. During this process, the main controller continuously monitors the voltage phase of the AC power supply. When it detects that the voltage is about to reach the zero-crossing point within a preset time t (e.g., 1 ms), the main controller issues a power-off command at time t1, turning off all power switching devices, and the motor enters the inertial coasting state.

[0030] During the brief power outage period from t1 to t2 (lasting approximately 2t, covering t before and t after the zero-crossing point), the AC voltage amplitude is close to zero. Even maintaining power supply would not provide effective drive power; instead, it would reduce system efficiency due to conduction losses of switching devices and current harmonic losses. Therefore, this invention actively disconnects the power during this period, eliminating ineffective power consumption, while simultaneously utilizing the rotor's rotational inertia to maintain rotation, preparing for the next commutation step. During this period, the rotor continues to rotate approximately 90 mechanical degrees.

[0031] At time t2, the AC power supply completes zero crossing and enters the positive half-cycle (voltage is positive). After the main controller detects the zero crossing and a preset delay time t elapses, the Hall sensor detects that the rotor has rotated to the position where the N pole has passed (outputs "1"), satisfying the commutation conditions for the second step. The main controller immediately outputs a new control signal, causing the power switching device to switch the connection mode: connecting the first terminal to the phase line L and the second terminal to the neutral line N, thus re-powering the motor.

[0032] During the time interval t2 to t3 (approximately Tt in duration), the current direction changes, flowing from the phase line through the first winding and the second winding to the neutral line. The positive magnetic field (N pole) generated by the first winding repels the rotor's N pole, while the negative magnetic field (S pole) generated by the second winding attracts the rotor's N pole. The winding magnetic fields work together to generate a positive driving torque, propelling the rotor to continue rotating. When the preset time before the zero-crossing point is detected again, the main controller issues a power-off command at time t3, initiating the next brief inertial coasting phase.

[0033] This process repeats continuously. The control system uses the AC power frequency as a reference (e.g., 50Hz corresponds to 20ms per complete working cycle), and through precise synchronization of the Hall signal with the AC cycle, it achieves a complete "power-on, power-off, and commutation sequence" within each half-cycle. The Hall signal's flipping frequency, the power switch's operating frequency, and the motor's rotation frequency are all strictly synchronized with the AC power frequency, forming a stable synchronous operating state. Throughout the entire operation, the direction and intensity of the stator magnetic field maintain an optimal match with the rotor's magnetic pole position, ensuring that the drive torque is always at its positive maximum value, achieving high-efficiency, low-loss motor drive control.

[0034] When the motor needs to rotate in reverse, the control system achieves this by changing the matching logic between the Hall signal and the AC current cycle. Specifically, in reverse control mode, if the Hall sensor detects the rotor's S pole passing by at the initial moment t0 (outputs "0"), the main controller waits for the AC power supply to enter the positive half-cycle (voltage is positive) before satisfying the first commutation condition. At this time, the output control signal activates the power switching device, connecting the first terminal to the phase line L and the second terminal to the neutral line N, thus starting to supply power to the motor. Current flows from the phase line through the first winding and the second winding to the neutral line. The positive magnetic field N pole generated by the first winding attracts the rotor's S pole (opposite to the repulsive relationship in forward control), while the negative magnetic field S pole generated by the second winding repels the rotor's S pole. The magnetic fields of the two windings work together to generate a reverse driving torque, pushing the rotor to accelerate in the opposite direction. During subsequent commutation, the controller always maintains the reverse matching logic of "positive half-cycle corresponding to S pole detection, negative half-cycle corresponding to N pole detection," thus achieving continuous and stable reverse synchronous operation. Users can switch between forward and reverse logic using external direction selection signals (such as DIP switches or control commands), thereby flexibly controlling the initial rotation direction of the motor.

[0035] Furthermore, during the motor startup phase, since the initial rotor position may be random, the control system can be programmed with a startup assistance program. First, a short position search pulse is used to determine the rotor's initial polarity and obtain the initial output state of the Hall sensor. Then, based on a preset rotation direction command (which can be set via an external direction selection signal such as a DIP switch, control port level, or communication command), and in conjunction with the current Hall state, the control system selects whether to power on the motor during the positive or negative half-cycle of the AC power supply, thus determining the initial rotation direction. For example, when the Hall sensor detects the S pole (output "0") and forward rotation is required, the control system waits for the AC power to enter the negative half-cycle before starting power supply; if reverse rotation is required, it waits for the AC power to enter the positive half-cycle before starting power supply. After determining the initial power supply timing, the main controller provides a large starting current to overcome the static friction torque. Once the rotor begins to rotate and a stable Hall signal is established, the system switches to the normal synchronous commutation control mode and continues operation according to the corresponding commutation logic. During steady-state operation of the motor, if a sudden load change occurs, the control system can detect speed fluctuations in real time by monitoring changes in the Hall signal period. It can also adjust the power supply timing or voltage amplitude (if an adjustable power supply is used) in conjunction with current feedback. In this way, the initial rotation direction of the motor can be controlled by program control to determine whether to power the motor during the positive half-cycle or the negative half-cycle of the AC circuit.

[0036] The beneficial effects of the technical solution of this invention are as follows: By acquiring the rotor magnetic pole position information and AC power cycle information, a correspondence between the magnetic pole position and the AC power cycle is established. Combined with the selective power supply strategy during the positive or negative half-cycle of the AC power supply and the optimization of the connection method between the first and second terminals and the AC power supply according to the rotor position, a first-step commutation control based on the magnetic pole position is formed. At the same time, by disconnecting the power supply for a preset time before the AC power supply crosses zero and reconnecting it after the zero-crossing point of the next power supply cycle, a second-step commutation control based on the power cycle is formed. This two-step commutation mechanism realizes the phase matching between the stator magnetic field and the permanent magnet rotor magnetic field, avoids the reverse torque and invalid current caused by phase mismatch in traditional control methods, and eliminates the invalid power consumption and switching losses during the voltage zero crossing period, and reduces the copper loss and iron loss caused by harmonic current, thereby significantly improving the overall operating efficiency of the single-phase AC permanent magnet synchronous motor.

[0037] See Figure 2 In a preferred embodiment, based on the rotor magnetic pole position and AC power cycle information, power is supplied to the first and second windings during the positive or negative half-cycle of the AC power supply, and the connection method between the first and second terminals and the AC power supply is determined, including: Step S31: Determine the preset detection position; Step S32: When the first magnetic pole of the rotor is in the preset detection position, power is supplied to the first winding and the second winding during the positive half-cycle of the AC power supply. Step S33: When the second magnetic pole of the rotor is in the preset detection position, power is supplied to the first winding and the second winding during the negative half-cycle of the AC power supply. The first and second magnetic poles have opposite polarities, and the first and second ends are connected to the AC power source in different ways.

[0038] In this embodiment, a preset detection position is determined. The preset detection position is the installation position of the Hall sensor on the motor stator, and the selection of this position directly affects the accuracy of magnetic pole position detection and the accuracy of commutation timing. Depending on different application requirements and control accuracy requirements, one or more preset detection positions can be set.

[0039] When a single preset detection position is set, a single Hall sensor scheme is used. In this configuration, the first and second windings are arranged opposite each other on the stator. Preferably, the two windings are symmetrically distributed 180 degrees along the inner circumference of the stator, forming a complete circular magnetic circuit around the rotor shaft. The Hall sensor is installed on the circumferential path formed by the two windings, specifically at the outer radial position of the rotor magnetic poles during rotation, ensuring that the rotor magnetic poles can effectively pass through the sensing area of ​​the Hall sensor during rotation. Preferably, the Hall sensor is installed at the geometric center of the first and second windings, or at a position offset by 30-60 electrical degrees from the front end of one of the windings, to achieve optimal commutation advance angle control.

[0040] When multiple preset detection positions are set, a multi-Hall sensor redundancy detection scheme can be adopted to improve system reliability and position resolution. For example, when using two Hall sensors, the two sensors are arranged with an electrical angle difference of 90 degrees along the stator circumference, forming orthogonal position detection. This can more accurately determine the instantaneous position and rotation direction of the rotor, which is particularly suitable for applications requiring forward and reverse rotation control or high-precision speed regulation. As another example, when three Hall sensors are set, the three Hall sensors can be evenly distributed along the stator circumference or configured at specific angles: a uniform distribution scheme with an electrical angle difference of 120 degrees can be used, in which case the output signals of the three sensors can form a standard three-phase Hall code, providing six clear commutation point position information, achieving more refined magnetic pole position identification; alternatively, a non-uniform distribution scheme with an electrical angle difference of 60 degrees and 120 degrees can be used, optimizing the sensor layout according to the specific winding configuration and magnetic pole structure, providing higher position resolution at certain specific rotor positions. The multi-Hall sensor scheme also has fault redundancy functionality. When one sensor fails, the system can continue to maintain basic position detection functions through the signals of the remaining sensors, improving the system's fault tolerance and operational reliability.

[0041] After determining the preset detection position and installing the Hall sensor, the control system determines the real-time position of the rotor magnetic poles based on the output signal of the Hall sensor. In this embodiment, the first magnetic pole of the rotor is defined as the N pole, and the second magnetic pole as the S pole, with opposite polarities. When the first magnetic pole (N pole) of the rotor rotates to the preset detection position, that is, when the Hall sensor detects a positive magnetic field, the Hall sensor outputs a high-level signal "1". At this time, the main controller (MCU) receives this high-level signal, synchronously detects the period information of the AC power supply, and determines that the current AC power supply is in the positive half-cycle (the voltage is positive). Then, the main controller issues a control command to connect the first end of the first winding to the phase line (L line) of the single-phase AC power supply through the power switching device, and at the same time connects the second end of the second winding to the neutral line (N line), supplying power to the first and second windings during the positive half-cycle of the AC power supply. At this time, the current flows from the phase line to the first winding through the first end, then flows in series through the second winding, and finally flows from the second end to the neutral line, forming a complete circuit. Under this power supply configuration, the positive magnetic field (N pole) generated by the first winding generates a repulsive force on the N pole of the rotor, pushing the rotor to rotate in a predetermined direction; the negative magnetic field (S pole) generated by the second winding generates an attractive force on the N pole of the rotor, pulling the rotor to continue moving forward, while repelling the S pole of the rotor. The magnetic fields of the two windings work together to generate a continuous and stable positive driving torque.

[0042] After the rotor continues to rotate approximately 180 mechanical degrees, the rotor's second magnetic pole (S pole) rotates to the preset detection position, i.e., when the Hall sensor detects the reverse magnetic field, the Hall sensor outputs a low-level signal "0". At this time, the main controller receives this low-level signal, synchronously detects the AC power supply cycle information, and determines that the current AC power supply is in the negative half-cycle (the voltage is negative). The main controller then issues a new control command, changing the connection method through a power switching device to connect the second end of the second winding to the phase line (L line) of the single-phase AC power supply, while simultaneously connecting the first end of the first winding to the neutral line (N line). Power is supplied to the first and second windings during the negative half-cycle of the AC power supply. At this time, the current direction changes, flowing from the phase line end through the second end into the second winding, then in series through the first winding, and finally from the first end to the neutral line end. Under this power supply configuration, the positive magnetic field (N pole) generated by the second winding attracts the S pole of the rotor, pulling the rotor forward; the negative magnetic field (S pole) generated by the first winding repels the S pole of the rotor, pushing the rotor to continue rotating, while attracting the N pole of the rotor, thus forming a continuous and stable positive driving torque again.

[0043] It can be seen that the connection methods of the first and second terminals to the AC power supply are different in the two working states. During the positive half-cycle, the first terminal is connected to the phase line and the second terminal is connected to the neutral line. During the negative half-cycle, the second terminal is connected to the phase line and the first terminal is connected to the neutral line. Through this alternating connection method, combined with the periodic voltage change of the AC power supply and the rotation position of the rotor magnetic pole, the precise synchronous matching of the stator magnetic field direction and the rotor magnetic pole position is achieved.

[0044] The switching of the connection method between the first and second terminals and the AC power supply can be achieved through various power switching devices. In low-cost, low-to-medium power applications, mechanical contactors or relays can be used. The coils of the contactors or relays are driven by control signals output from the main controller (MCU), causing their contacts to actuate and thus changing the connection between the winding terminals and the power supply terminals. The contactor solution has the advantages of simple structure, low cost, and strong anti-interference capability, but its operating speed is relatively slow (typical response time 10-50ms), and it suffers from contact wear and arcing problems. It is suitable for conventional applications with low commutation frequencies (such as 50Hz power frequency).

[0045] In applications requiring fast response and high reliability, solid-state power switching devices such as triacs, anti-parallel thyristor pairs, IGBT modules, or MOSFET switch combinations can be used.

[0046] In terms of control, the main controller can be implemented using a microcontroller (MCU), such as a 32-bit ARM Cortex-M series MCU or a cost-effective 8-bit / 16-bit microcontroller. The main functional modules of the MCU include a Hall signal input capture module for real-time reading of the Hall sensor's level state and recording of magnetic pole position information; an AC power cycle detection module for identifying the positive and negative half-cycles and zero-crossing moments of the power supply through an external zero-crossing detection circuit or internal ADC sampling; a timer module for precise timing and generating preset power-off times; an output control module for generating the control signals (relay drive signals or thyristor trigger pulses) required to drive the power switching devices; and a main control logic program that outputs corresponding control commands in real-time according to the Hall signal and power cycle information, following preset commutation logic and timing requirements.

[0047] The MCU's control program adopts an interrupt-driven and state machine architecture design: the transition edge of the Hall signal triggers an external interrupt, and the current magnetic pole position state is read in the interrupt service routine; the zero-crossing point of the AC power supply triggers another external interrupt or timer interrupt, records the power cycle information, and triggers commutation judgment; the main loop program searches the preset commutation control table according to the Hall state and the power cycle state, and outputs the corresponding power switch control signal.

[0048] See Figure 3In a preferred embodiment, determining the connection method between the first terminal and the second terminal and the AC power supply includes: Step S34: When the first magnetic pole is located at the preset detection position, connect the first end of the first winding to the phase line of the AC power supply and connect the second end of the second winding to the neutral line of the AC power supply. Step S35: When the second magnetic pole is located at the preset detection position, connect the second end of the second winding to the phase line of the AC power supply and connect the first end of the first winding to the neutral line of the AC power supply.

[0049] This embodiment clarifies the specific connection relationship between the winding ends and the power supply ends, achieving current direction reversal and magnetic field polarity change through precise endpoint switching. Specifically, when the Hall sensor detects that the first magnetic pole (e.g., the N pole) is located at a preset detection position, the Hall sensor outputs a high-level signal "1". After receiving this signal, the main controller controls the power switching device to operate, connecting the first end of the first winding to the phase line (L line) of the AC power supply through the switching device K1, and simultaneously connecting the second end of the second winding to the neutral line (N line) of the AC power supply through the switching device K2. At this time, the current path is: phase line L, switch K1, first end, first winding, second winding, second end, switch K2, neutral line N, forming a complete power supply circuit. In this connection method, current flows into the first winding from the first end. According to the right-hand screw rule, the first winding generates a positive magnetic field (N pole), which repels the first magnetic pole (N pole) of the rotor. The current continues to flow through the second winding and flows out from the second end. The second winding generates a negative magnetic field (S pole), which attracts the first magnetic pole (N pole) of the rotor and repels the second magnetic pole (S pole) of the rotor. The magnetic fields of the two windings work together to drive the rotor to rotate in the predetermined direction.

[0050] When the rotor rotates approximately 180 degrees, the second magnetic pole (e.g., the S pole) reaches the preset detection position. The Hall sensor detects the reverse magnetic field and outputs a low-level signal "0". Upon receiving this signal, the main controller immediately changes the control state of the power switching device, connecting the second end of the second winding to the phase line (L line) of the AC power supply via switch K3, and simultaneously connecting the first end of the first winding to the neutral line (N line) of the AC power supply via switch K4. At this time, the current path changes to: phase line L, switch K3, second end, second winding, first winding, first end, switch K4, neutral line N. Under this connection method, the current direction is completely reversed. The current flows into the second winding from the second end, and the second winding generates a positive magnetic field (N pole), which attracts the second magnetic pole (S pole) of the rotor. The current continues to flow through the first winding and flows out from the first end, generating a negative magnetic field (S pole) of the first winding, which repels the second magnetic pole (S pole) of the rotor and attracts the first magnetic pole (N pole) of the rotor, thus forming a continuous positive driving torque again.

[0051] By establishing a clear endpoint correspondence, a 180-degree phase switch of the winding current direction is achieved. Compared to the traditional single-end switching method, the dual-end synchronous switching mechanism adopted in this embodiment ensures the integrity and determinism of the current path, avoiding potential risks of floating ends or short circuits, and improving the safety and reliability of the system. This connection method ensures that the two windings always operate in series. Regardless of the connection state, the current flows sequentially through the first and second windings (only in opposite directions), ensuring that the current amplitude of the two windings is always equal and the magnetic field strength remains consistent. This symmetrical power supply method avoids the problems of single winding overload or magnetic field imbalance, resulting in a more uniform stator magnetic field distribution, smaller torque fluctuations, and smoother motor operation.

[0052] From a circuit topology perspective, this embodiment actually constitutes a simplified H-bridge circuit structure. The four switching devices (K1, K2, K3, K4) work together, and bidirectional controllability of the current direction is achieved through the alternating conduction of the diagonal switches (K1 and K2 conduct simultaneously, or K3 and K4 conduct simultaneously).

[0053] In addition, to prevent the risk of short circuits that may occur during the commutation process, a dead time should be set in the control program. This means that a short time interval (typically a few microseconds to tens of microseconds) is inserted between turning off the currently conducting set of switches (such as K1 and K2) and turning on the next set of switches (such as K3 and K4). This ensures that the old switch is completely turned off before the new switch is turned on, avoiding a shoot-through short circuit caused by the simultaneous conduction of the upper and lower bridge arms (phase side and neutral side).

[0054] In a preferred embodiment, the single-phase AC permanent magnet synchronous motor further includes a Hall sensor, with the preset detection position being the mounting position of the Hall sensor.

[0055] In a preferred embodiment, disconnecting the power supply a preset time before the AC power supply zero-crossing point and reconnecting the power supply after the zero-crossing point of the next power supply cycle includes: the relationship between the preset time t and the half-cycle time T of the AC power supply satisfies: T / 20≤t≤T / 5.

[0056] When the AC power supply reaches a preset time t before reaching zero crossing, the main controller issues a power-off command, shutting down all power switching devices and cutting off the motor power supply. At this time, the motor enters an inertial coasting state, continuing to rotate based on the rotor's rotational inertia. The setting of this preset time t needs to comprehensively consider various factors such as power supply frequency, rotor speed, and load inertia.

[0057] For a standard 50Hz power supply, the half-cycle time of the AC power is T = 10ms. According to the relationship T / 20 ≤ t ≤ T / 5 in this embodiment, the range of the preset time t can be calculated to be 0.5ms ≤ t ≤ 2ms. Preferably, t = T / 10 = 1ms is taken, that is, the power supply is disconnected 1ms before the AC power supply crosses zero. The AC voltage at this moment is about 30.9% of the peak voltage (sin(π×1 / 10) ≈ 0.309). Although the voltage has not completely dropped to zero, it is already at a low level. The effective power contribution of continuing to supply power is limited, and it will increase switching losses and harmonic losses. By actively disconnecting the power at this moment, the full utilization of the high voltage stage in the early stage is ensured, and the inefficient energy consumption near the zero crossing point is avoided.

[0058] The specific working process is as follows: Assuming the current operation is in the positive half-cycle of AC power, the Hall sensor detects that the first magnetic pole (N pole) of the rotor is located at the preset detection position (Hall signal output high level "1"). At this time, the first terminal is connected to the phase line, and the second terminal is connected to the neutral line, and the motor operates normally with power supply. The main controller monitors the phase of the AC power supply in real time through an internal timer or zero-crossing detection circuit. When it detects that there is still time t (e.g., 1ms) before the zero-crossing point, it immediately outputs a power-off control signal, causing all power switching devices (K1, K2, or relays) to turn off simultaneously, and the motor power supply circuit is disconnected.

[0059] During the period following the power outage, the rotor continues to rotate due to inertia. During this time, the Hall sensor continuously monitors the rotor's magnetic pole position, and the main controller reads the Hall signal value in real time. When the AC power supply crosses zero and enters the negative half-cycle, the main controller waits for the Hall signal to change from a high level "1" to a low level "0," indicating that the rotor has rotated to the second magnetic pole (S pole) and reached the preset detection position. At this point, the main controller reconnects the power supply at the corresponding time after the zero-crossing (usually with a delay of approximately t), outputting a new control signal to turn on power switching devices K3 and K4, connecting the second terminal to the phase line and the first terminal to the neutral line, completing the commutation and restoring power supply.

[0060] Once the motor enters a stable operating state, the rotor's rotational speed is precisely synchronized with the AC power frequency. At this time, the Hall signal's switching frequency is exactly the same as the AC power frequency, both being 50Hz (with a period of 20ms). The Hall signal generates one transition within each AC cycle, and the power switch's switching action is also synchronized. From a timing perspective, within each AC half-cycle, the actual power supply time of the motor is approximately (T-2t), and the power outage time is approximately 2t (including t before and after the zero-crossing point). Taking t=T / 10 as an example, the power supply time accounts for (TT / 5) / T=80%, and the power outage time accounts for 20%. Near the zero-crossing point, the system is only shut off for a brief period of about 2ms. During this time, the corresponding AC voltage is in the low-voltage range below 30.9% of the peak voltage, having a very small impact on the overall output power (theoretically, the loss is less than 10%), but eliminating all switching losses, conduction losses, and harmonic losses during this period, resulting in a significant improvement in overall efficiency.

[0061] Further explanation regarding the preset time t value range: When t is set to the lower limit T / 20, for a 50Hz power supply, t=0.5ms, the power outage time is extremely short, and the low-voltage range near the zero-crossing point still has a significant amount of time in the power supply state. Although a high power supply time ratio (90%) is guaranteed, ineffective losses in the low-voltage range still exist, and the energy-saving effect is not ideal. When t is set to the upper limit T / 5, t=2ms, the power outage time is longer, and the low-voltage range near the zero-crossing point is almost completely excluded from the power supply period, resulting in significant energy savings. However, the power supply time ratio drops to 60%, which may lead to insufficient driving force for light loads or startup conditions. Therefore, in practical applications, the optimal value can be flexibly selected within this range according to the specific load characteristics and efficiency requirements. For constant load applications such as fans and pumps, it is recommended to use t=T / 10 to achieve the best balance between efficiency and performance. For variable loads or applications requiring frequent start-stop, the t value can be appropriately reduced (e.g., t=T / 15) to enhance driving capability. For light loads or applications that emphasize extreme energy saving, the t value can be appropriately increased (e.g., t=T / 8) to maximize energy saving.

[0062] Furthermore, in practical engineering applications, the preset time t can be designed as an adjustable parameter, allowing online adjustment via MCU program configuration or an external adjustment interface. The system can dynamically optimize the value of the preset time t based on real-time monitored operating parameters such as motor current, speed, and temperature rise, achieving adaptive control. For example, when a sudden increase in load or a decrease in speed is detected, the value of t can be automatically reduced to extend the power supply time and enhance drive capability; when light load operation or a decrease in efficiency is detected, the value of t can be automatically increased to shorten the ineffective power supply time and improve energy efficiency. This intelligent parameter optimization strategy enables the motor system to maintain optimal operating conditions under various operating conditions.

[0063] In a preferred embodiment, disconnecting the power supply a preset time before the AC power supply zero-crossing point and reconnecting the power supply after the zero-crossing point of the next power supply cycle further includes: When the preset time t is 1 / 10 of the AC power supply half-cycle time, the ratio η of the voltage integral value of the actual power supply section to the voltage integral value of the complete half-cycle satisfies: η = 1.95 / 2 = 97.5%.

[0064] This embodiment demonstrates the rationality and effectiveness of the preset power outage time from the perspective of energy utilization efficiency through quantitative calculations. Specifically, for a standard sinusoidal AC power supply, its voltage expression is V(t) = V_m·sin(ωt), where V_m is the peak voltage and ω is the angular frequency. Within a complete half-cycle (0 to π), the integral value of the voltage is: ∫0^πsin(x)dx=2; This integral value represents the total energy contribution of the AC voltage over a complete half-cycle. When the control method of this invention is used, and the power supply is disconnected at a preset time t=T / 10 before the zero crossing, the corresponding phase angle is 9π / 10 (i.e., 0.9π), and the actual power supply section is from 0 to 9π / 10. Within this section, the integral value of the voltage is: ∫0^(9π / 10)sin(x)dx=1.95; The comparison shows that although the power supply was interrupted for 10% of the time (from 9π / 10 to π), its impact on the total energy contribution was minimal because the voltage amplitude in this segment was extremely low (decreasing from 30.9% of the peak value to 0). The effective energy utilization rate η of the actual power supply segment can be expressed as: The calculation result η = (actual voltage integral value of the power supply section) / (voltage integral value of the complete half-cycle) = 1.95 / 2 = 97.5% indicates that by actively cutting off power at t = T / 10 before the zero-crossing point, the system can still obtain 97.5% of the effective voltage energy of the complete half-cycle, losing only 2.5% of the voltage integral value. More importantly, this lost 2.5% voltage integral is mainly concentrated in the low-voltage range near the zero-crossing point. Due to the low voltage amplitude in this range, even if power supply continues, the actual effective power provided is extremely limited. On the contrary, additional ineffective losses will occur due to the non-ideal characteristics of current at low voltage (such as diode effect and hysteresis loss).

[0065] Further analysis from the perspective of power loss reveals that in the low-voltage range near the zero-crossing point (9π / 10 to π, and 0 to π / 10 in the next half-cycle), although the voltage integral accounts for only 2.5%, the switching losses, conduction losses, and harmonic losses in this range are not negligible. When switching devices conduct under low voltage, a significant amount of reactive current and harmonic current is generated due to potential phase deviations between the current and voltage. Magnetic components (iron cores) have a larger hysteresis loop area under low flux density, resulting in relatively increased iron losses. Harmonic currents in the windings cause additional copper losses. These losses often account for a larger proportion of the effective power in the low-voltage range than the proportion of effective power in that range. Therefore, by actively disconnecting power to eliminate this inefficient range, although 2.5% of the voltage integral is sacrificed, the actual total loss savings can reach 5%-10% or even higher, resulting in an increase in the overall operating efficiency of the motor.

[0066] In actual operation, the effectiveness of this control strategy is reflected in the following aspects: The Hall sensor is set to increase the voltage output signal when the N pole approaches and decrease the output signal when the S pole approaches. Based on the Hall signal waveform, the peak position corresponds to the moment when the rotor's N pole is closest to the Hall sensor and the S pole is furthest away. At this time, if the AC power supply is in the positive half-cycle, the power is switched on to supply power to the motor. The positive magnetic field generated by the first winding repels the rotor's N pole, and the negative magnetic field generated by the second winding attracts the rotor's N pole, causing the motor to rotate forward. When the rotor rotates to the point where the S pole approaches the Hall sensor, the Hall signal is at a trough. If the AC power supply is in the negative half-cycle at this time, the connection mode is switched to supply power to the motor. The positive magnetic field generated by the second winding attracts the rotor's S pole, and the negative magnetic field generated by the first winding repels the rotor's S pole, causing the motor to continue rotating forward.

[0067] Before each AC zero-crossing point, at a preset time t=T / 10, the main controller shuts off all power switches, and the motor is de-energized. At this time, the rotor continues to rotate due to inertia, and the Hall sensor continuously monitors the magnetic pole position. After the AC current passes the zero-crossing point and enters the next half-cycle, the main controller waits for the Hall signal to jump to the corresponding polarity state (from N pole to S pole, or from S pole to N pole). After confirming that the rotor has rotated to the correct position, the main controller restarts the motor power supply at the corresponding time after the zero-crossing point (usually delayed by about t=T / 10), completing a new commutation and drive cycle.

[0068] Once the motor enters a stable operating state, the frequency of the Hall signal is precisely synchronized with the AC power frequency, both being standard power frequencies (e.g., 50Hz). In the timing waveform, the Hall signal and the power switch's conduction signal are exactly in sync with the AC power, and the motor is only turned off for a brief period of approximately 2t (t before and after the zero-crossing point). Since the effective value (RMS) of the AC voltage is extremely low, close to zero, within the t=T / 10 interval before and after the zero-crossing point, the energy contribution during this period is negligible. By precisely controlling the turn-off time within a reasonable range (T / 20≤t≤T / 5), the system can eliminate all ineffective losses near the zero-crossing point with almost no loss of effective power, bringing the motor's efficiency close to its theoretical upper limit.

[0069] See Figure 4 In a preferred embodiment, the control method for a single-phase AC permanent magnet synchronous motor further includes: Step S50: Determine whether the rotor magnetic pole position and AC power cycle meet the preset power supply conditions; Step S51: When the power supply conditions are met, power is supplied to the first winding and the second winding. Step S52: When the power supply conditions are not met, disconnect the power supply and continue to judge in the subsequent half-cycle. When the power supply conditions are met again, restore the power supply.

[0070] This embodiment is mainly used to deal with the problem of motor speed fluctuation caused by load changes, external interference, and start-up transients during actual operation. It ensures that the system can maintain the synchronous relationship between rotor rotation and AC power supply under various operating conditions, avoid reverse torque or braking effect caused by phase mismatch, and ensure stable operation and efficient output of motor.

[0071] Specifically, the preset power supply conditions refer to the phase matching relationship that must be satisfied between the rotor magnetic pole position and the AC power supply cycle. That is, when the Hall sensor detects that the rotor's first magnetic pole (N pole) is in the preset detection position (Hall signal output "1"), the AC power supply must be in the positive half-cycle (voltage is positive); when the Hall sensor detects that the rotor's second magnetic pole (S pole) is in the preset detection position (Hall signal output "0"), the AC power supply must be in the negative half-cycle (voltage is negative). Only when these two conditions are satisfied simultaneously can the direction of the magnetic field generated by the stator winding form a correct attraction-repulsion match with the rotor magnetic pole position, generating a positive driving torque to drive the motor to rotate in the predetermined direction.

[0072] At the beginning of each AC half-cycle (i.e., a preset time t after the zero-crossing), the main controller reads the output signal of the Hall sensor and the cycle information of the AC power supply in real time to determine the power supply conditions. The determination logic can be expressed as follows: Condition 1: If (Hall signal = "1") and (AC power supply = positive half cycle), then the power supply condition is met, and the positive power supply operation is performed (the first end is connected to the phase line, and the second end is connected to the neutral line). Condition 2: If (Hall signal = "0") and (AC power supply = negative half cycle), then the power supply condition is met, and reverse power supply operation is performed (the second terminal is connected to the phase line, and the first terminal is connected to the neutral line). Condition 3: If (Hall signal = "1") but (AC power supply = negative half cycle), or (Hall signal = "0") but (AC power supply = positive half cycle), then the power supply condition is not met, and the power is kept off.

[0073] Under ideal synchronous operation, the rotor's rotation period is strictly synchronized with the AC power supply period, and the Hall signal's flip point precisely corresponds to the AC power supply's zero-crossing point (considering the preset delay time t). Each judgment satisfies the power supply conditions, ensuring continuous and stable motor operation. However, under the following non-ideal operating conditions, phase mismatch may occur: During the startup phase, when the motor starts from a standstill, the initial rotor position is random, and a mismatch may occur between the Hall signal and the AC power supply cycle. For example, when the AC power supply is in the positive half-cycle, the Hall sensor may detect the S pole (output "0"). If power is forced at this time, it will generate reverse torque, hindering the rotor's forward rotation. The control method in this embodiment maintains a power-off state when such a mismatch is detected, waiting for the AC power supply to enter the next half-cycle (negative half-cycle). At this point, the Hall signal matches the power supply cycle, satisfying the power supply conditions, and the system begins to power on and start the motor. Through this waiting synchronization mechanism, positive torque is generated on the first power supply, achieving a smooth and reliable startup process.

[0074] When the load suddenly increases during motor operation, the rotor experiences a significant resistance torque, causing a sudden drop in rotational speed and resulting in a phase lag between the rotor and the AC power supply. For example, the rotor's N pole should ideally reach the preset detection position at the beginning of the positive half-cycle of the AC power supply. However, due to the increased load and slower rotational speed, the N pole may only reach the detection position halfway through the positive half-cycle. If power is supplied according to the original timing at this time, the matching relationship between the stator magnetic field and the rotor position will deteriorate during the latter half of the power supply period. This embodiment continuously assesses the power supply conditions. When a phase mismatch is detected (e.g., the Hall signal is still "0" at the end of the positive half-cycle), the power supply is immediately disconnected to avoid generating reverse torque or invalid current. The system reassesses in the next half-cycle. If the rotor continues to rotate to the matching position due to inertia and residual driving force, the power supply is restored; if there is still a mismatch, the system waits for the next cycle. Through this dynamic adjustment mechanism, the motor can automatically restore synchronization within 2-3 AC power cycles.

[0075] When the load suddenly decreases, the resistance torque on the rotor decreases, and the rotational speed increases instantaneously, causing the rotor phase to lead relative to the AC power supply. At this time, the Hall signal flips earlier than the expected zero-crossing point, possibly occurring at the end of the previous half-cycle. The control method in this embodiment also addresses this through a power supply condition judgment mechanism: when phase lead is detected (e.g., the Hall signal has flipped to "1" at the end of the negative half-cycle), the system disconnects the power supply for the current half-cycle in advance, waiting for the next positive half-cycle to arrive before re-judging and re-supplying. Since the rotor speed is already too high, during the waiting power-off period, the rotor will slightly decelerate due to the lack of driving force, automatically approaching the synchronization state.

[0076] In some applications, the motor may be affected by external vibration, impact, or electromagnetic interference, causing instantaneous fluctuations in speed or glitches in the Hall sensor output signal. This embodiment can detect these anomalies in a timely manner through a real-time judgment mechanism for each half-cycle. For genuine speed fluctuations, the system automatically corrects them through the aforementioned waiting synchronization mechanism; for occasional glitches in the Hall signal, software filtering or multiple sampling confirmation mechanisms can be added to the control program to avoid erroneous power outages due to misjudgments.

[0077] In a preferred embodiment, determining whether the rotor magnetic pole position and the AC power cycle meet the preset power supply conditions includes: if the rotor corresponding magnetic pole has not yet reached the preset detection position when the expected half-cycle of power supply arrives, the power is disconnected and the power is re-energized after the rotor magnetic pole rotates to the preset detection position.

[0078] When the motor speed decreases due to increased load, increased resistance, or other reasons, the rotor's rotation period will be longer than the AC power supply period, resulting in phase lag. Assuming the motor operates normally in the first half-cycle, the rotor's N pole is at the preset detection position, the AC power supply is in the positive half-cycle (T to 2T period), and the system is supplying power normally. At the end of this half-cycle, the system disconnects the power supply at a preset time t before the zero-crossing point, according to a predetermined sequence. Subsequently, the AC power supply enters the negative half-cycle (T to 2T period). According to normal synchronous operation logic, the rotor should have rotated approximately 180 mechanical angles by this time, the S pole should have reached or approached the preset detection position, and the Hall sensor output should have flipped from "1" to "0".

[0079] However, when the motor speed slows down, at the beginning of the negative half-cycle (i.e., a preset time t after the zero-crossing), the main controller detects that the Hall sensor output is still "1", indicating that the rotor's S pole has not yet reached the preset detection position, and the rotor phase is significantly lagging behind the AC power phase. If the power supply is forced according to the negative half-cycle connection method (the second end is connected to the phase line, and the first end is connected to the neutral line), since the rotor is still near the N pole close to the Hall position, the magnetic field generated by the stator will mismatch with the rotor's current position, which may produce a weak driving torque or even a reverse torque component, reducing motor efficiency.

[0080] Therefore, the main controller immediately performs a power-off operation, shutting down all power switching devices and keeping the motor in a power-off coasting state. During this period, the rotor continues to rotate based on the previously acquired rotational inertia, gradually approaching the preset detection position. The main controller continuously monitors the output signal of the Hall sensor. When the Hall signal changes from "1" to "0", it indicates that the rotor's S pole has successfully reached the preset detection position, and the rotor's magnetic pole position matches the current negative half-cycle power supply requirement. The main controller then restarts the power supply, outputting a control signal to turn on the power switching devices according to the negative half-cycle connection method (second terminal connected to the phase line, first terminal connected to the neutral line), and the motor resumes normal drive. At this time, although the power supply timing is delayed relative to the start point of this negative half-cycle, because the rotor position and stator magnetic field direction are correctly matched, the system can still generate effective positive drive torque, driving the rotor to continue rotating and accelerating, gradually approaching the synchronous state.

[0081] After power is restored, the control system continues to operate according to normal timing. Before the zero-crossing point of the negative half-cycle, the power supply is disconnected again at a preset time t (e.g., 1ms) to complete the power supply process for that cycle. When the next positive half-cycle arrives, the system repeats the above judgment process, checking whether the Hall signal has flipped to "1" (whether the N pole has reached the preset detection position). If it has, the system supplies power normally; if it has not, it continues to wait until the conditions are met before supplying power again.

[0082] In a preferred embodiment, determining whether the rotor magnetic pole position and the AC power cycle meet the preset power supply conditions includes: if the rotor corresponding magnetic pole exceeds the preset detection position when the expected half-cycle of power supply arrives, the power is disconnected and the power is re-energized after the rotor magnetic pole reaches the preset detection position again.

[0083] As the motor speed increases, the rotor's rotational speed exceeds the synchronous speed of the AC power supply. At the arrival of the second positive half-cycle (the period from 2T to 3T), i.e., at a preset time t after the zero-crossing point, the main controller detects that the Hall sensor's output is already "1," indicating that the rotor's N-pole has already passed the preset detection position, and may even have rotated a certain angle. At this point, the rotor's actual position is ahead of the expected position, and its phase is ahead of the AC power supply phase.

[0084] More precisely, the N-pole position detected at this point is actually the position the rotor has reached ahead of schedule due to its continued high-speed rotation from the previous cycle; the rotor may have already passed the optimal power supply start point. If power is immediately supplied in the positive half-cycle mode (first end connected to the phase line, second end connected to the neutral line), since the rotor position is already ahead, the relative position relationship between the stator magnetic field and the rotor magnetic poles is no longer in the optimal matching state. This reduces the efficiency of the generated driving torque and may even produce a partial braking effect, hindering the rapid rotation of the rotor.

[0085] Therefore, the main controller determines that the power supply conditions are not met and immediately executes or maintains the power-off state, shutting down all power switching devices. The motor continues to rotate due to inertia in the power-off state, but due to the lack of driving torque, the rotor gradually decelerates under the influence of friction and air resistance. The rotor's N pole continues to rotate forward, and after passing the preset detection position, it continues to move forward, with the Hall sensor output remaining at "1".

[0086] After the rotor continues to rotate approximately 180 mechanical degrees, the S pole reaches the preset detection position, and the Hall sensor output flips from "1" to "0". At this time, although the AC power supply is still in the positive half-cycle (between 2T and 3T), the rotor's magnetic pole has changed to the S pole, which is closer to the Hall position, failing to meet the power supply conditions for the positive half-cycle (the positive half-cycle should correspond to the N pole position), and the system remains in a power-off state. The rotor continues to rotate and decelerate under inertia. When the AC power supply passes the next zero-crossing point and enters the negative half-cycle (between 3T and 4T), the rotor may still be rotating. The main controller checks the Hall sensor at the beginning of this negative half-cycle (time t after the zero-crossing point). If the output is "0" (the S pole is at the preset detection position) and the AC power supply is in the negative half-cycle, the power supply conditions are met, and the system resumes power supply. If the Hall sensor has already flipped to "1" (indicating that the rotor speed is still too fast and the N pole has again exceeded the preset position), the power supply remains off, waiting for the rotor to rotate one more revolution before the S pole reaches the preset detection position again.

[0087] It is important to note that when determining whether the rotor has exceeded the preset detection position, the system actually makes this judgment indirectly by detecting the matching relationship between the state of the Hall signal and the AC power cycle. For example, at the beginning of the positive half-cycle when the N pole should be detected (the Hall signal should be "1"), if the system has already detected the Hall signal flipping to "1" at the end of the previous cycle, or if the system detects that the Hall signal is already "0" at the beginning of the current cycle (indicating that the N pole has already passed and the S pole has been reached), this is considered a case of "exceeding the preset detection position," and the system should be powered off and wait for resynchronization.

[0088] This invention further proposes a control system for a single-phase AC permanent magnet synchronous motor, comprising: A single-phase AC permanent magnet synchronous motor includes a rotor and a stator. The stator includes a first winding and a second winding connected in series. Hall effect sensors are installed inside the end cover of a single-phase AC permanent magnet synchronous motor to detect the position of the rotor's magnetic poles. Zero-crossing detection module: This module is used to detect the zero-crossing point of the AC power supply and to obtain the period information of the AC power supply. The power supply switching device is electrically connected to the first winding, the second winding, and the AC power supply respectively, so as to control the connection mode of the first winding and the second winding with the AC power supply. The controller is electrically connected to the Hall sensor zero-crossing detection module and the power supply switching device, and is used to execute the control method of the single-phase AC permanent magnet synchronous motor in the aforementioned embodiment.

[0089] In this embodiment, the single-phase AC permanent magnet synchronous motor includes a rotor and a stator. The rotor adopts a permanent magnet structure with alternating N and S pole pairs, preferably made of high-performance neodymium iron boron permanent magnet material to provide a strong and stable magnetic field. The stator includes a first winding and a second winding connected in series, symmetrically distributed along the inner circumference of the stator, preferably arranged 180 degrees opposite each other. The first winding has a first end, and the second winding has a second end. The two windings are connected in series by a wire to form a complete current loop. The stator core adopts a silicon steel sheet laminated structure to reduce eddy current losses and hysteresis losses.

[0090] The Hall sensor is installed inside the end cover of the single-phase AC permanent magnet synchronous motor, specifically on the radially outer side of the rotor's magnetic pole rotation trajectory, for example, maintaining an air gap distance of 2-5mm from the rotor's outer surface. The Hall sensor detects the rotor's magnetic pole position in real time. It outputs a high-level signal "1" when the rotor's N pole passes through the sensor's sensing area and a low-level signal "0" when the rotor's S pole passes through. The Hall sensor preferably uses unipolar or bipolar Hall switching elements, such as models A3144 and OH137, which feature fast response, strong anti-interference capability, and reliable operation. The Hall sensor connects to the controller's digital input port via a signal line, transmitting rotor magnetic pole position information to the controller in real time.

[0091] The zero-crossing detection module is used to detect the zero-crossing point of the AC power supply and obtain its period information. Typical implementations of the zero-crossing detection module include: using a resistor divider network to step down the AC voltage for sampling, and then converting the sinusoidal voltage signal into a square wave signal using a comparator circuit, with the rising and falling edges of the square wave corresponding to the zero-crossing point of the AC power supply; or using an optocoupler isolation circuit, where the on and off states of the optocoupler indicate the positive and negative half-cycles of the AC power supply; or using a transformer to step down the voltage, then rectifying and filtering it to form a DC signal, and using an ADC (Analog-to-Digital Converter) to sample the voltage waveform in real time, with the controller software algorithm identifying the zero-crossing point and calculating the period. The output signal of the zero-crossing detection module is connected to the controller's interrupt input port or timer input port through an isolation circuit, ensuring that the controller can accurately capture the zero-crossing point and record the AC power supply's period parameters (such as a frequency of 50Hz, a period of 20ms, and a half-cycle of 10ms).

[0092] The power supply switching device electrically connects the first winding, the second winding, and the AC power supply respectively, and is used to control the connection mode of the first and second windings with the AC power supply. The specific implementation of the power supply switching device can employ mechanical relay groups, solid-state relay groups, thyristor switching circuits, or IGBT / MOSFET bridge circuits, etc. A typical topology is an H-bridge or bidirectional switching structure, for example, including at least four power switching devices K1, K2, K3, and K4: K1 controls the connection of the first terminal to the AC power supply phase line, K2 controls the connection of the second terminal to the AC power supply neutral line, K3 controls the connection of the second terminal to the AC power supply phase line, and K4 controls the connection of the first terminal to the AC power supply neutral line. The controller outputs a switching signal that allows switching between two power supply modes: Mode 1, where K1 and K2 are on (K3 and K4 are off), with current flowing from the phase line through the first terminal, the first winding, the second winding, and the second terminal to the neutral line; and Mode 2, where K3 and K4 are on (K1 and K2 are off), with current flowing from the phase line through the second terminal, the second winding, the first winding, and the first terminal to the neutral line. The power supply switching device also includes a drive circuit to amplify the low-level control signal output by the controller into a drive signal sufficient to drive the power switching devices, and to provide necessary isolation and overcurrent protection.

[0093] The controller is the core component of the entire control system, electrically connected to the Hall sensor, zero-crossing detection module, and power supply switching device. The controller can employ a 32-bit ARM Cortex-M series microcontroller (such as STM32F103, STM32F407, etc.) or a cost-effective 8-bit / 16-bit microcontroller (such as ATmega328, PIC16F877, etc.). The software program running internally in the controller adopts an interrupt-driven and state machine architecture design. Edge changes in the Hall sensor signal trigger an external interrupt, updating the rotor position state in the interrupt service routine; the zero-crossing detection signal triggers another external interrupt or a timer interrupt, recording the zero-crossing moment and updating the power cycle state; the timer interrupt is used to generate a precise delay for the preset power-off time t. The main loop program, based on the current rotor position state, power cycle state, and timing state, looks up the preset control logic table and outputs the corresponding switching control signals. The program also includes auxiliary functions such as a startup management module, overcurrent protection module, stall detection module, out-of-step recovery module, and fault diagnosis module to ensure the safe and reliable operation of the system under various operating conditions.

[0094] This control system achieves efficient, intelligent, and adaptive control of a single-phase AC permanent magnet synchronous motor by rationally configuring various functional modules and centrally coordinating control through a controller. The system has a clear structure, high modularity, and is easy to implement and maintain, possessing good engineering practicality and promotional value. By executing the control methods of the aforementioned embodiments, this control system enables the single-phase AC permanent magnet synchronous motor to maintain a high-efficiency, low-loss, and stable synchronous operating state under various load conditions, significantly improving the motor's overall performance and application adaptability.

[0095] The above description is only a part or preferred embodiment of the present invention. Neither the text nor the drawings should limit the scope of protection of the present invention. All equivalent structural transformations made using the content of the present invention specification and drawings under the overall concept of the present invention, or direct / indirect applications in other related technical fields, are included within the scope of protection of the present invention.

Claims

1. A control method of a single-phase AC permanent magnet synchronous motor including a rotor and a stator, the stator including a first winding and a second winding connected in series, the first winding having a first end, the second winding having a second end, characterized in that, The control method of the single-phase alternating current permanent magnet synchronous motor comprises the following steps: Obtaining rotor magnetic pole position information; Obtaining alternating current power cycle information; According to the rotor magnetic pole position information and the alternating current power cycle information, the first winding and the second winding are powered in the positive half cycle or the negative half cycle of the alternating current power, and the connection mode of the first end and the second end to the alternating current power is determined; The power is disconnected at a preset time before the zero point of the alternating current power, and the power is reconnected after the zero point of the next power cycle.

2. The control method of a single-phase AC permanent-magnet synchronous motor according to claim 1, characterized by, The connection mode of the first end and the second end to the alternating current power is determined according to the rotor magnetic pole position information and the alternating current power cycle information, and the first winding and the second winding are powered in the positive half cycle or the negative half cycle of the alternating current power. A preset detection position is determined; When the first magnetic pole of the rotor is at the preset detection position, the first winding and the second winding are powered in the positive half cycle of the alternating current power; When the second magnetic pole of the rotor is at the preset detection position, the second winding and the first winding are powered in the negative half cycle of the alternating current power; Wherein, the polarities of the first magnetic pole and the second magnetic pole are opposite, and the connection modes of the first end and the second end to the alternating current power are different.

3. The control method of a single-phase AC permanent-magnet synchronous motor according to claim 2, characterized by, The connection mode of the first end and the second end to the alternating current power comprises: When the first magnetic pole is at the preset detection position, the first end of the first winding is connected to the phase line of the alternating current power, and the second end of the second winding is connected to the neutral line of the alternating current power; When the second magnetic pole is at the preset detection position, the second end of the second winding is connected to the phase line of the alternating current power, and the first end of the first winding is connected to the neutral line of the alternating current power.

4. The control method of a single-phase AC permanent-magnet synchronous motor according to claim 2, characterized by, The single-phase alternating current permanent magnet synchronous motor further comprises a Hall sensor, and the preset detection position is the installation position of the Hall sensor.

5. The control method of a single-phase AC permanent-magnet synchronous motor according to claim 1, characterized by, The power is disconnected at a preset time before the zero point of the alternating current power, and the power is reconnected after the zero point of the next power cycle. The relationship between the preset time t and the alternating current power half cycle time T satisfies: T / 20≤t≤T / 5.

6. The control method of a single-phase AC permanent-magnet synchronous motor according to claim 5, characterized by, The power is disconnected at a preset time before the zero point of the alternating current power, and the power is reconnected after the zero point of the next power cycle. The relationship between the preset time t and the alternating current power half cycle time T satisfies: When the preset time t is 1 / 10 of the alternating current power half cycle time, the ratio η of the voltage integral value of the actual power supply section to the voltage integral value of the complete half cycle satisfies: η=1.95 / 2=97.5%.

7. The control method of a single-phase AC permanent-magnet synchronous motor according to claim 2, characterized by, The control method of the single-phase alternating current permanent magnet synchronous motor further comprises: Judging whether the rotor magnetic pole position and the alternating current power cycle satisfy a preset power supply condition; When the power supply condition is satisfied, the first winding and the second winding are powered; When the power supply condition is not satisfied, the power is disconnected, and the subsequent half cycle is continuously judged. When the power supply condition is satisfied again, the power is restored.

8. The control method of a single-phase AC permanent-magnet synchronous motor according to claim 7, characterized by, If the corresponding magnetic pole of the rotor has not reached the preset detection position when the expected power supply half cycle arrives, the power is disconnected and the rotor magnetic pole is rotated to the preset detection position before the power is reconnected.

9. The control method of a single-phase AC permanent-magnet synchronous motor according to claim 7, characterized by, The judging whether the rotor magnetic pole position and the alternating current power cycle meet the preset power supply condition comprises: if the corresponding magnetic pole of the rotor exceeds the preset detection position when the expected power supply half cycle arrives, the power supply is turned off at this time and the power supply is restarted after the magnetic pole of the rotor reaches the preset detection position again.

10. A control system for a single-phase AC permanent magnet synchronous motor, characterized by Comprise: A single-phase alternating current permanent magnet synchronous motor, comprising a rotor and a stator, the stator comprising a first winding and a second winding connected in series; A Hall sensor arranged inside an end cover of the single-phase alternating current permanent magnet synchronous motor to detect the magnetic pole position of the rotor; A zero-crossing detection module for detecting the zero-crossing point of the alternating current power supply and obtaining the cycle information of the alternating current power supply; A power supply switching device electrically connected to the first winding, the second winding and the alternating current power supply respectively to control the connection mode of the first winding and the second winding with the alternating current power supply; A controller electrically connected to the Hall sensor, the zero-crossing detection module and the power supply switching device respectively, for executing the control method of the single-phase alternating current permanent magnet synchronous motor according to any one of claims 1 to 9.

Images