A motor control method and a motor control circuit

Abstract

The application discloses a motor control method and a motor control circuit. The method comprises the following steps: controlling a motor module to perform initial starting after power-on, performing zero-crossing detection on a first voltage signal obtained by sampling a receiving end circuit after initial starting, and obtaining a zero-crossing detection result; and controlling a working state of the motor module based on the zero-crossing detection result, and actively loading through the motor module, so that a voltage signal containing a zero-crossing point can be sampled, and then motor speed control can be performed according to the zero-crossing detection result, so that the motor module powered by a wireless power supply mode is controlled in speed, and the motor can rotate at a uniform speed.

Description

Technical Field

[0001] This application relates to the field of motor technology, and in particular to a motor control method and a motor control circuit. Background Technology

[0002] An electric motor is essentially an electromagnetic device that converts or transmits electrical energy based on the law of electromagnetic induction. It serves as a power source for electrical appliances and various machines. For example, a single-phase series motor, commonly known as a series-wound motor or universal motor, is widely used in power tools such as blenders and soymilk makers due to its high speed, small size, light weight, and convenient speed adjustment. During motor operation, it is often necessary to control the motor speed to maintain a stable position. For instance, blenders typically have several speed settings, each with a different motor speed. Therefore, the motor needs to be controlled to keep its speed stable during operation.

[0003] With the application of wireless power supply in power tools, the aforementioned need for motor speed control still exists, but current technology cannot yet achieve speed control for wirelessly powered motors. Summary of the Invention

[0004] The main technical problem addressed by this application is to provide a motor control method and a motor control circuit that can control a motor module to achieve uniform rotation when using wireless power supply.

[0005] To solve the above-mentioned technical problems, one technical solution adopted in this application is: to provide a motor control method, the method comprising: controlling the motor module to perform the initial start after power-on; performing zero-crossing detection on the first voltage signal sampled by the receiving circuit after the initial start to obtain the zero-crossing detection result; and controlling the working state of the motor module based on the zero-crossing detection result. The motor module is powered by wireless power supply, and the motor module is connected to the wireless power supply receiver to form a receiving circuit.

[0006] The initial startup of the motor module after power-on includes: acquiring a second voltage signal sampled from the receiving circuit before the initial startup; using the second voltage signal to predict the zero-crossing time of the first voltage signal; and controlling the motor module to perform the initial startup based on the zero-crossing time.

[0007] The process of controlling the motor module to perform the initial start based on the zero-crossing moment includes: determining the current target gear of the motor module; determining the initial start time based on the current target gear and the zero-crossing moment; and controlling the motor module to perform the initial start at the initial start time.

[0008] Wherein, both the first voltage signal and the second voltage signal are periodic signals; using the second voltage signal to predict the zero-crossing time of the first voltage signal includes: determining the time corresponding to the target amplitude within the period of the second voltage signal; predicting the zero-crossing time based on the time corresponding to the target amplitude, wherein the zero-crossing time is the time corresponding to the zero-crossing point within the period of the first voltage signal.

[0009] The target amplitude is the minimum amplitude within the period of the second voltage signal.

[0010] Among them, predicting the zero-crossing time based on the time corresponding to the target amplitude includes: taking the time after the time corresponding to the target amplitude with a preset time interval as the zero-crossing time.

[0011] The motor module includes a series-wound motor.

[0012] The method of controlling the working state of the motor module based on the zero-crossing detection results includes: controlling the motor module to enter the first state whenever the zero-crossing point of the first voltage signal is detected, determining the state switching time based on the time of the zero-crossing point detection, and controlling the motor module to enter the second state at the state switching time. One of the first state and the second state is the start of operation and the other is the end of operation.

[0013] To solve the above-mentioned technical problems, another technical solution adopted in this application is: to provide a motor control circuit, which includes: a receiving circuit, a sampling circuit, a zero-crossing detection circuit, and a control module. The receiving circuit includes a motor module and a receiving end for wirelessly powering the motor module, and the motor module is connected to the receiving end. The sampling circuit is used to sample the voltage signal of the receiving end. The zero-crossing detection circuit is used to perform zero-crossing detection on the voltage signal output by the sampling circuit to obtain the zero-crossing detection result. The control module is used to control the motor module to perform the initial start after power-on, and to control the working state of the motor module based on the zero-crossing detection result output by the zero-crossing detection circuit after the initial start.

[0014] Specifically, the voltage signal output by the sampling circuit after the initial start of the motor module is the first voltage signal, and the voltage signal output by the sampling circuit before the initial start of the motor module is the second voltage signal. The control module is also connected to the output of the sampling circuit. The control module executes the initial start of the motor module after power-on by controlling the motor module to perform the initial start. Specifically, the control module uses the second voltage signal to predict the zero-crossing time of the first voltage signal, and controls the motor module to perform the initial start based on the zero-crossing time.

[0015] Wherein, both the first voltage signal and the second voltage signal are periodic signals; the control module executes the prediction of the zero-crossing time of the first voltage signal using the second voltage signal, specifically including: determining the time corresponding to the target amplitude within the period of the second voltage signal; predicting the zero-crossing time based on the time corresponding to the target amplitude, wherein the zero-crossing time is the time corresponding to the zero-crossing point within the period of the first voltage signal.

[0016] The sampling circuit includes a voltage divider resistor, a sampling resistor, and a first filter circuit. The first filter circuit is connected in parallel with the sampling resistor. The first end of the voltage divider resistor is connected to the receiving circuit as the sampling end. The first end of the sampling resistor is connected to the second end of the voltage divider resistor and serves as the output end of the sampling circuit. The second end of the sampling resistor is grounded.

[0017] The zero-crossing detection circuit is a comparator circuit. The first input terminal of the comparator circuit is connected to the output terminal of the sampling circuit, the second input terminal of the comparator circuit is grounded, and the output terminal of the comparator circuit serves as the output terminal of the zero-crossing detection circuit.

[0018] The comparator circuit is a comparator; or, the comparator circuit includes a first resistor, a second resistor, and a transistor, with the emitter of the transistor serving as the second input terminal, the collector of the transistor serving as the output terminal, and connected to the power supply through the second resistor. The base of the transistor is connected to one end of the first resistor, and the other end of the first resistor serves as the first input terminal.

[0019] The receiving circuit also includes a rectifier circuit, and the motor module is connected to the receiving end through the rectifier circuit.

[0020] The sampling terminal of the sampling circuit is connected to the end of the rectifier circuit that is connected to the motor module; or, the motor control circuit further includes a first rectifier diode and a second rectifier diode, one end of the first rectifier diode and one end of the second rectifier diode are respectively connected to the two ends of the receiving end, and the other ends of the first rectifier diode and the other ends of the second rectifier diode are both connected to the sampling terminal of the sampling circuit.

[0021] The receiving circuit also includes a second filter circuit, which is connected in parallel with the motor module to the first DC connection terminal and the second DC connection terminal of the rectifier circuit.

[0022] In the above scheme, the motor module is first started after power-on, and then the first voltage signal sampled by the receiving circuit after the initial start is zero-crossing detected. Based on the obtained zero-crossing detection result, the working state of the motor module is controlled. By actively loading the motor module, the voltage signal containing the zero-crossing point can be sampled. Then, the motor speed can be controlled according to the zero-crossing detection result, thus realizing the speed control of the motor module powered by wireless power supply, so that the motor can rotate at a constant speed. Attached Figure Description

[0023] Figure 1 This is a flowchart illustrating an embodiment of the motor control method of this application;

[0024] Figure 2 This is a flowchart illustrating another embodiment of step S110 of this application;

[0025] Figure 3 This is a flowchart illustrating another embodiment of the motor control method of this application;

[0026] Figure 4 This is a schematic diagram of the framework of an embodiment of the motor control circuit of this application;

[0027] Figure 5 This is a schematic diagram of the framework of another embodiment of the motor control circuit of this application;

[0028] Figure 6 This is a schematic diagram of the framework of another embodiment of the motor control circuit of this application;

[0029] Figure 7 This is a schematic diagram of the second voltage signal in one embodiment of the motor control method of this application;

[0030] Figure 8 This is a schematic diagram of the first voltage signal in one embodiment of the motor control method of this application. Detailed Implementation

[0031] To make the purpose, technical solution and effects of this application clearer and more explicit, the following describes this application in further detail with reference to the accompanying drawings and embodiments.

[0032] In this article, the term "and / or" simply describes the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A alone, A and B simultaneously, or B alone. Additionally, the character " / " generally indicates that the preceding and following related objects have an "or" relationship. Furthermore, "more" in this article means two or more objects.

[0033] It is understood that the methods of this application may include the methods provided by any of the following method embodiments and any combination of the following method embodiments that do not conflict.

[0034] Please see Figure 1 , Figure 1 This is a flowchart illustrating an embodiment of the motor control method of this application, the method comprising:

[0035] Step S110: Control the motor module to perform the initial start-up after power-on.

[0036] It should be noted that the motor control method in this application can control a motor module that uses wireless power supply. Specifically, the working circuit includes a transmitter circuit and a receiver circuit. The receiver circuit includes a motor module and a wireless power supply receiver that are connected to each other. The motor module includes a motor that needs to be speed controlled.

[0037] Step S120: Perform zero-crossing detection on the first voltage signal sampled by the receiving circuit after the initial startup to obtain the zero-crossing detection result.

[0038] After the motor module is initially started, the voltage across the motor module changes periodically. A first voltage signal can be used to characterize the voltage cycle across the motor module, and the first voltage value starts and ends at zero level in each voltage cycle. The cycle of the first voltage signal matches the cycle of the power supply signal, for example, it matches the cycle of the mains power. The first voltage signal has a zero-crossing point and is synchronized with the zero-crossing time of the mains power. The zero-crossing detection result can be used to determine the moment when the first voltage signal is zero, thus reflecting the voltage cycle across the motor module.

[0039] Step S130: Based on the zero-crossing detection results, control the working state of the motor module.

[0040] Understandably, to ensure the motor rotates at a constant speed, the motor module is controlled to start and stop operating at a fixed phase of the voltage cycle across its terminals, thus maintaining a uniform motor speed. Therefore, the zero-crossing detection result reflects the voltage cycle across the motor module, allowing for control based on this voltage cycle to ensure the motor rotates at a constant speed.

[0041] Furthermore, the zero-crossing detection result reflects the zero-crossing moment, which can be considered the end of the previous voltage cycle and the beginning of the next voltage cycle. To achieve speed control of the motor, the operating state of the motor module can be switched at fixed phases within the voltage cycle. Switching operating states includes controlling the motor module to start working and controlling the motor module to stop working. For example, within a voltage cycle, the zero-crossing moment can be used as one of the moments when the motor module switches operating states, and a fixed phase within that cycle can be determined as another moment for switching operating states; alternatively, the voltage cycle can be determined based on the zero-crossing moment, and two fixed non-zero-crossing moments can be determined within each cycle, controlling the motor module to switch operating states at the corresponding moments.

[0042] The above scheme controls the motor module to perform an initial start-up after power-on, and then performs zero-crossing detection on the first voltage signal sampled by the receiving circuit after the initial start-up. Based on the obtained zero-crossing detection result, the working state of the motor module is controlled. By actively loading the motor module, it is possible to sample voltage signals containing zero-crossing points. Then, the motor speed can be controlled according to the zero-crossing detection result, thus realizing speed control of the motor module powered by wireless power supply, enabling the motor to rotate at a constant speed.

[0043] In some embodiments, step S110 can be controlling the motor module to perform the initial start after power-on at any time. After the initial start, a voltage signal containing the zero-crossing point, i.e., the first voltage signal, can be sampled. Then, the working state of the motor module can be controlled directly according to the first voltage signal sampled after the initial start. Thus, after the first start, the speed control of the motor can be realized, so that the motor speed is uniform and the electrical equipment using the motor module can achieve stable operation at different speeds.

[0044] Please see Figure 2 , Figure 2 This is a flowchart illustrating another embodiment of step S110 of this application. Specifically, step S110 may include the following steps:

[0045] Step S211: Obtain the second voltage signal sampled from the receiving circuit before the initial startup.

[0046] It should be noted that, in order to ensure the motor maintains a constant speed after initial startup, the switching time of the motor module's operating state can be determined based on the zero-crossing detection result of the first voltage signal. The time interval between the motor's start-up time and the zero-crossing point, determined using the above method, is fixed, and the time interval between the motor's end-of-operation time and the zero-crossing point is also fixed. Based on this, to ensure the motor maintains a constant speed from the initial startup, the initial startup time of the motor module, as the initial start-up time of the motor module, should also conform to the aforementioned fixed time interval between the start-up time and the first voltage signal.

[0047] The second voltage signal is obtained by sampling the receiving circuit before the motor module's initial startup. It can be understood that the second and first voltage signals can be obtained using the same sampling circuit at the same location; the second voltage signal is obtained before the motor module's initial startup, and the first voltage signal is obtained after the initial startup. It should be noted that since the motor module has not yet started for the first time, the second voltage signal does not contain a zero-crossing point. Therefore, the second voltage signal cannot be directly used to determine the initial startup time using zero-crossing detection to control the initial startup of the motor module.

[0048] Step S212: Use the second voltage signal to predict the zero-crossing time of the first voltage signal.

[0049] It should be noted that the value of the second voltage signal also changes periodically, and there is a certain correlation between the second voltage signal and the first voltage signal. Based on the correlation between the second voltage signal and the first voltage signal, the zero-crossing time of the first voltage signal can be predicted, thereby controlling the initial start-up of the motor module.

[0050] In some embodiments, the second voltage signal and the first voltage signal may be sampled at different locations, and the above-mentioned correlation exists between them. The second voltage signal may also be used to predict the zero-crossing time of the first voltage signal.

[0051] Step S213: Control the motor module to perform the initial start-up based on the zero-crossing time.

[0052] After predicting the zero-crossing time of the first voltage signal, based on the fixed time interval between the start time and the zero-crossing time of the first voltage signal, the motor module is controlled to perform the initial start at the corresponding time.

[0053] The above solution, by performing zero-point prediction before the initial start-up, can accurately drive the motor module to start working at the corresponding phase, avoiding the situation where the initial start-up speed of the motor is too fast or too slow due to starting at any time. This allows the motor to maintain a constant speed rotation from the initial start-up, improving the stability of electrical equipment using the above motor module.

[0054] Please see Figure 3 , Figure 3 This is a flowchart illustrating another embodiment of the motor control method of this application. Specifically, the method may include the following steps:

[0055] Step S310: Obtain the second voltage signal sampled from the receiving circuit before the initial startup.

[0056] The receiving circuit includes a motor module, which may include a series-wound motor, and the series-wound motor is the target for speed control.

[0057] The first and second voltage signals are periodic signals. The first voltage signal contains zero-crossing points, and its period can be determined based on these zero-crossing points. For the second voltage signal, its period can be determined based on its target amplitude.

[0058] Step S212 can be achieved through steps S320 and S330.

[0059] Step S320: Determine the time corresponding to the target amplitude within the period of the second voltage signal.

[0060] After sampling the second voltage signal for a period of time, and after the second voltage signal has gone through several cycles, the target amplitude of the second voltage signal within the cycle can be determined. The target amplitude can be the maximum value or the minimum value, etc. The time corresponding to the target amplitude can be used to mark the start and end times of the second voltage signal cycle.

[0061] Step S330: Predict the zero-crossing time based on the time corresponding to the target amplitude.

[0062] After determining the time corresponding to the target amplitude, the voltage period of the second voltage signal can be determined. Based on the correlation between the voltage periods of the first and second voltage signals, the zero-crossing time in the first voltage signal can be predicted.

[0063] It is understandable that there is a fixed phase difference between the period of the first voltage signal determined by the zero-crossing point and the period of the second voltage signal determined by the target amplitude. Since the relevant parameters of the working circuit where the motor module is located do not change, this fixed phase difference remains constant and can usually be determined by testing a certain working circuit in advance. Therefore, the time interval between the moment corresponding to the target amplitude of the second voltage signal and the zero-crossing point is fixed and can be determined by pre-testing.

[0064] Specifically, a preset time interval between the time corresponding to the target amplitude and the zero-crossing time can be determined through pre-testing. For any electrical device using the above-mentioned working circuit, the preset time interval between the time corresponding to the target amplitude and the zero-crossing time will always hold when using this wireless power supply method. Step S330 can be achieved by taking the time interval after the preset time interval corresponding to the target amplitude as the zero-crossing time.

[0065] In a specific application scenario, the time corresponding to the minimum amplitude within the period of the second voltage signal is determined, and the time after the time corresponding to the minimum amplitude with a preset time interval is taken as the zero-crossing time.

[0066] Step S213 can be achieved through steps S340-S360.

[0067] Step S340: Determine the current target gear of the motor module.

[0068] It should be noted that electrical equipment using this motor module can include several speed settings to meet different user needs. Different speed settings correspond to different motor speeds, therefore the motor needs to maintain different speeds at different speeds. The initial start-up time and state transition time are also different for different speed settings; therefore, when controlling the motor module, the current target speed needs to be determined first.

[0069] Step S350: Determine the initial start time based on the current target gear and the zero-crossing time.

[0070] The zero-crossing time can be determined through step S330. Based on the target gear, the initial start time can be determined based on the zero-crossing time.

[0071] For example, the frequency of the first voltage signal is 50Hz, and one voltage cycle is 0.02s. The initial start time and the time when the motor module switches to start working corresponding to the first gear can be 0.01s after the zero-point time, and the time when the motor module switches to stop working can be the zero-point time. The initial start time and the time when the motor module switches to start working corresponding to the second gear can be 0.005s after the zero-point time, and the time when the motor module switches to stop working can be the zero-point time.

[0072] Step S360: Control the motor module to perform the initial start at the initial startup time.

[0073] Step S370: Perform zero-crossing detection on the first voltage signal sampled by the receiving circuit after the initial startup, and obtain the zero-crossing detection result.

[0074] The relevant description of step S370 can be found in the aforementioned content about step S120, and will not be repeated here.

[0075] Step S380: Based on the zero-crossing detection results, control the working state of the motor module.

[0076] Specifically, step S380 can be implemented through the following steps: each time a zero-crossing point of the first voltage signal is detected, the motor module is controlled to enter the first state, and the state switching time is determined based on the time when the zero-crossing point is detected, and the motor module is controlled to enter the second state at the state switching time. In this case, one of the first state and the second state is the start of operation, and the other is the end of operation.

[0077] In a specific application scenario, the motor module stops working whenever the zero-crossing point of the first voltage signal is detected. The state switching time is determined based on the time when the zero-crossing point is detected. The state switching time can be a time interval of a certain fixed duration from the zero-crossing point time. The motor module starts working at the state switching time.

[0078] The above method can be applied to electrical appliances that use motor modules as the driving force, such as blenders and soy milk makers. Since the circuit parameters of appliances of the same model are consistent, the preset duration corresponding to the same model can be obtained through pre-testing. Therefore, the zero-crossing time can be predicted for all appliances of this model using the above method to control the initial start-up of the motor module. After the initial start-up, the motor module is controlled based on the zero-crossing detection results. This also enables uniform motor speed control when the motor module is powered wirelessly.

[0079] Please see Figure 4 , Figure 4 This is a schematic diagram of the framework of an embodiment of the motor control circuit of this application.

[0080] In this embodiment, the motor control circuit 40 includes a receiving circuit 41, a sampling circuit 42, a zero-crossing detection circuit 43, and a control module 44.

[0081] The receiving circuit 41 includes a motor module and a receiver for wirelessly powering the motor module. A sampling circuit 42 is connected to the receiving circuit 41 and samples the voltage signal from the receiving circuit 41. A zero-crossing detection circuit 43 is connected to the output of the sampling circuit 42 and performs zero-crossing detection on the voltage signal output by the sampling circuit 42 to obtain the zero-crossing detection result. A control module 44 is connected to both the zero-crossing detection circuit 43 and the receiving circuit 41, and controls the motor module in the receiving circuit 41 to perform its initial startup after power-on. Based on the zero-crossing detection result output by the zero-crossing detection circuit 43 after the initial startup, it controls the operating state of the motor module in the receiving circuit 41.

[0082] In a specific application scenario, the control module 44 controls the motor module in the receiving circuit 41 to perform the initial start-up after power-on. After the initial start-up, the zero-crossing detection circuit 43 acquires the first voltage signal output by the sampling circuit 42 and performs zero-crossing detection to obtain the zero-crossing detection result. The control module 44 receives the zero-crossing detection result and controls the working state of the motor module in the receiving circuit 41, thereby realizing speed control of the motor module in the receiving circuit 41.

[0083] In the above scheme, the control module controls the motor module to perform the initial start-up after power-on. Then, the zero-crossing detection circuit performs zero-crossing detection on the first voltage signal sampled by the sampling circuit. Based on the obtained zero-crossing detection result, the control module controls the working state of the motor module. By actively loading the motor module, it is possible to sample the voltage signal containing the zero-crossing point. Then, the motor speed can be controlled according to the zero-crossing detection result, realizing speed control of the motor module powered by wireless power supply, so that the motor can rotate at a constant speed.

[0084] In some embodiments, the control module 44 is also connected to the output terminal of the sampling circuit 42. This embodiment uses the example where both the first voltage signal and the second voltage signal are sampled by the same sampling circuit 42 at the same location. After the initial start of the motor module, the voltage signal output by the sampling circuit 42 is the first voltage signal, and after the initial start of the motor module, the voltage signal output by the sampling circuit 42 is the second voltage signal. In a specific application scenario, before the initial start of the motor module in the receiving circuit 41, the sampling circuit 42 samples the receiving circuit 41 and outputs the second voltage signal. The control module 44 receives the second voltage signal, predicts the zero-crossing time of the first voltage signal, and controls the motor module in the receiving circuit 41 to perform the initial start based on the zero-crossing time. After the initial start, the sampling circuit 42 samples the receiving circuit 41 and outputs the first voltage signal. The zero-crossing detection circuit 43 acquires the first voltage signal output by the sampling circuit 42 and performs zero-crossing detection to obtain the zero-crossing detection result. The control module 44 receives the zero-crossing detection result and controls the operating state of the motor module in the receiving circuit 41.

[0085] More specifically, both the first and second voltage signals are periodic signals. The control module 44 uses the second voltage signal to predict the zero-crossing time of the first voltage signal, which can be achieved through the following steps: determining the time corresponding to the target amplitude within the period of the second voltage signal, and predicting the zero-crossing time based on the time corresponding to the target amplitude. Here, the zero-crossing time is the time corresponding to the zero-crossing point within the period of the first voltage signal, and the target amplitude is a value that can identify the period of the second voltage signal, which may include, but is not limited to, the maximum amplitude, minimum amplitude, etc.

[0086] The above solution, by performing zero-point prediction before the initial start-up, can accurately drive the motor module to start working at the corresponding phase, avoiding the situation where the initial start-up speed of the motor is too fast or too slow due to starting at any time. This allows the motor to maintain a constant speed rotation from the initial start-up, improving the stability of electrical equipment using the above motor module.

[0087] Please see Figure 5 , Figure 5 This is a schematic diagram of another embodiment of the motor control circuit of this application.

[0088] In this embodiment, the motor control circuit 50 includes a receiving circuit 51, a sampling circuit 52, a zero-crossing detection circuit 53, and a control module 54.

[0089] The sampling circuit 52 includes a voltage divider resistor 521, a sampling resistor 522, and a first filter circuit 523. The first end of the voltage divider resistor 521 is connected to the receiving circuit 51 as the sampling end. The first end of the sampling resistor 522 is connected to the second end of the voltage divider resistor 521 and serves as the output end of the sampling circuit 52. The second end of the sampling resistor 522 is grounded. The first filter circuit 523 is connected in parallel with the sampling resistor 522.

[0090] The zero-crossing detection circuit 53 is a comparator circuit. The first input terminal of the comparator circuit is connected to the output terminal of the sampling circuit 52, the second input terminal of the comparator circuit is grounded, and the output terminal of the comparator circuit serves as the output terminal of the zero-crossing detection circuit 53.

[0091] The receiving circuit 51 includes a receiving end 511 and a motor module 512. It also includes a rectifier circuit 513, through which the motor module 512 is connected to the receiving end 511. It should be noted that the sampling terminal of the sampling circuit 52 can be connected between the rectifier circuit 513 and the motor module 512, or the sampling terminal of the sampling circuit 52 can also be connected between the receiving end 511 and the rectifier circuit 513. In this embodiment, the latter is used as an example.

[0092] The output terminal of the sampling circuit 52 is connected to the first input terminal of the zero-crossing detection circuit 53. The output terminals of the sampling circuit 52 and the zero-crossing detection circuit 53 are respectively connected to the control module 54. The control module 54 receives the second voltage signal output by the sampling circuit 52 to control the initial start of the motor module 512, and receives the zero-crossing detection result output by the zero-crossing detection circuit 53 to control the working state of the motor module 512 after the initial start.

[0093] In a specific application scenario, the second end of the voltage divider resistor 521 serves as the output of the sampling circuit 52. Before the initial start-up of the motor module 512, a second voltage signal is output to the control module 54. The control module 54 determines the time corresponding to the target amplitude within the period of the second voltage signal, predicts the zero-crossing time based on the time corresponding to the target amplitude, and controls the motor module 512 to perform the initial start-up based on the zero-crossing time. After the initial start-up, the sampling circuit 52 outputs a first voltage signal, the zero-crossing detection circuit 53 receives the first voltage signal and performs zero-crossing detection to obtain the zero-crossing detection result, and the control module 54 receives the above zero-crossing detection result to control the working state of the motor module 512.

[0094] In some embodiments, the sampling terminal of the sampling circuit 52 is connected between the rectifier circuit 513 and the motor module 512. For example, the sampling terminal of the sampling circuit 52 is connected to the end where the rectifier circuit 513 and the motor module 512 are connected. Then the sampling circuit 52 may not include the first filter circuit 523. Furthermore, the sampling circuit 52 may only be used to output the first voltage signal to obtain the zero-crossing detection result and control the working state of the motor module 512.

[0095] Please see Figure 6 , Figure 6 This is a schematic diagram of another embodiment of the motor control circuit of this application.

[0096] In this embodiment, the motor control circuit 60 includes a receiving circuit 61, a sampling circuit 62, a zero-crossing detection circuit 63, and a control module not shown in the figure.

[0097] The receiving circuit 61 includes a receiving terminal 611 and a motor module 612. It also includes a rectifier circuit 613. In this embodiment, the receiving terminal 611 includes a coil L and a capacitor C1. The rectifier circuit 613 is a bridge rectifier D0. The motor module 612 includes a series-wound motor and a switching transistor MOS1. The control module controls the initial start-up and changes in the operating state of the motor module 612 by outputting control signals to the switching transistor. The two ends of the receiving terminal 611 are connected to the two AC voltage input terminals of the bridge rectifier. The receiving circuit 61 also includes a second filter circuit 614. The second filter circuit 614 and the motor module 612 are connected in parallel to the first DC connection terminal and the second DC connection terminal of the rectifier circuit 613. In this embodiment, the second filter circuit 614 is a filter capacitor (C2).

[0098] The motor control circuit 60 also includes a first rectifier diode 64 and a second rectifier diode 65. One end of the first rectifier diode 64 and one end of the second rectifier diode 65 are respectively connected to the two ends of the receiving end 611. The other ends of the first rectifier diode 64 and the second rectifier diode 65 are both connected to the sampling end of the sampling circuit 62.

[0099] The sampling circuit 62 includes a voltage divider resistor 621, a sampling resistor 622, and a first filter circuit 623. In this embodiment, the voltage divider resistor 621 includes two connected resistors (R1, R2), and the first filter circuit 623 is a filter capacitor (C3). The first end of the voltage divider resistor 621 is connected as a sampling end to the other end of the first rectifier diode 64 and the other end of the second rectifier diode 65. The first end of the sampling resistor 622 is connected to the second end of the voltage divider resistor 621 and serves as the output end of the sampling circuit 62. The output end is connected to the control module and performs AD (analog-to-digital conversion) sampling. The second end of the sampling resistor 622 is grounded. The first filter circuit 623 is connected in parallel with the sampling resistor 622.

[0100] The zero-crossing detection circuit 63 includes a first resistor 631, a second resistor 632, and a transistor 633. The emitter of the transistor 633 is grounded as the second input terminal, and the collector of the transistor 633 is connected to the control module as the output terminal and connected to the power supply VCC (Volt Current Condenser) through the second resistor 632. The base of the transistor 633 is connected to one end of the first resistor 631, and the other end of the first resistor 631 is connected to the output terminal of the sampling circuit 62 as the first input terminal.

[0101] In some embodiments, the zero-crossing detection circuit 63 may also directly use a comparator.

[0102] In some embodiments, the sampling circuit 62 can be connected to the first DC connection terminal of the rectifier circuit 613, so as to... Figure 6 For example, it can be connected to the positive terminal of the bridge rectifier. In this case, the sampling circuit 62 may not include the first filter circuit 623, and the motor control circuit 60 may not include the first rectifier diode 64 and the second rectifier diode 65. In this embodiment, the motor control circuit 60 can be used to control the initial start of the motor module 612 at any time, and then the sampling circuit 62 obtains the first voltage signal for the zero-crossing detection circuit 63 to perform zero-crossing detection, so that the control module can perform control according to the zero-crossing detection result.

[0103] It should be noted that, Figure 6 The diagram also shows the transmitter circuit, which, combined with the motor control circuit 60, enables wireless power supply to the motor module 612 and achieves motor speed control under wireless power supply. In a specific application scenario, the transmitter circuit transmits a high-frequency signal with a 50Hz carrier wave, which is received by the receiver 611. The signal is rectified by the rectifier circuit 613, and the second filter circuit 614 filters out the high-frequency signal in the circuit, providing DC voltage power to the motor module 612.

[0104] Please see Figure 7 , Figure 7 This is a schematic diagram of the second voltage signal in one embodiment of the motor control method of this application.

[0105] It should be noted that high-power transmitters typically connect to 220V / 50Hz AC mains power, and the transmitted power uses high-frequency signals (e.g., 100kHz) for transmission. Therefore, the transmitted signal is a 50Hz waveform with a 100kHz envelope, and the receiver also receives this waveform. The wireless receiver receives a 50Hz high-frequency signal with approximately 100kHz. Because high-frequency signals have a relatively high speed, the high frequency needs to be filtered out, and only the 50Hz low frequency is used for sampling. The sampling circuit 62 includes a first filter circuit 623 to filter out the high-frequency signal and retain the 50Hz low-frequency signal. Before the initial start-up of the motor module 612, the second voltage signal output by the sampling circuit 62 is as follows: Figure 7 As shown, since the motor is not working, the circuit is in no-load mode, and the second voltage signal cannot reach zero, so zero-crossing detection cannot be used to directly control the motor to start. Figure 7 The document also provides the mains voltage. After the motor module 612 is initially started, the first voltage signal has the same period as the mains signal. However, at this time, the motor module 612 has not yet started, so the first voltage signal does not yet exist. The mains signal can be used to characterize the period of the first voltage signal. Figure 7 As shown, there is a time interval t between the minimum value of the second voltage signal and the zero-crossing point of the mains power signal (first voltage signal), and this t value is a fixed parameter of the circuit, which can be obtained in advance by testing the same circuit. Therefore, based on the minimum value of the second voltage signal, or other amplitudes that can characterize the period of the second voltage signal, the zero-crossing point of the first voltage signal can be predicted for use in controlling the initial start-up of the motor module 612.

[0106] Please see Figure 8 , Figure 8 This is a schematic diagram of the first voltage signal in one embodiment of the motor control method of this application.

[0107] After the motor module 612 is started for the first time, the sampling circuit 62 outputs the first voltage signal, such as... Figure 8 As shown, the period of the first voltage signal is consistent with that of the mains power signal, and the previous voltage cycle of the first voltage signal ends at a zero-crossing point, and the next voltage cycle begins at a zero-crossing point. The zero-crossing detection result obtained by performing zero-crossing detection based on the first voltage signal can be used to control the working state of the motor module 612 after its initial startup. Figure 8 The paper presents a possible control method in which the motor module 612 stops working at the zero-crossing point and starts working at the state switching time determined based on the zero-crossing point.

[0108] The above solution, by performing zero-point prediction before the initial start-up, can accurately drive the motor module to start working at the corresponding phase, avoiding the situation where the initial start-up speed of the motor is too fast or too slow due to starting at any time. This allows the motor to maintain a constant speed rotation from the initial start-up, further improving the stability of electrical equipment using the above motor module.

[0109] The above description is merely an embodiment of this application and does not limit the patent scope of this application. Any equivalent structural or procedural transformations made using the content of this application's specification and drawings, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of this application.

Claims

1. A motor control method, characterized in that, The method includes: The motor module is controlled to perform the initial start-up after power-on. The motor module is powered by wireless power supply and is connected to the wireless power supply receiver to form a receiver circuit. The first voltage signal sampled by the receiving circuit after the initial startup is subjected to zero-crossing detection to obtain the zero-crossing detection result. Based on the zero-crossing detection results, the operating state of the motor module is controlled; The initial start-up of the motor module after power-on includes: acquiring a second voltage signal sampled from the receiving circuit before the initial start-up; predicting the zero-crossing time of the first voltage signal using the second voltage signal; and controlling the motor module to perform the initial start-up based on the zero-crossing time.

2. The method according to claim 1, characterized in that, The step of controlling the motor module to perform the initial start based on the zero-crossing time includes: Determine the current target gear of the motor module; Based on the current target gear and the zero-crossing time, determine the initial start time; The motor module is controlled to perform the initial start at the initial start time.

3. The method according to claim 1, characterized in that, Both the first voltage signal and the second voltage signal are periodic signals; the step of using the second voltage signal to predict the zero-crossing time of the first voltage signal includes: Determine the time corresponding to the target amplitude within the period of the second voltage signal; Based on the time corresponding to the target amplitude, the zero-crossing time is predicted, wherein the zero-crossing time is the time corresponding to the zero-crossing point within the period of the first voltage signal.

4. The method according to claim 3, characterized in that, The target amplitude is the minimum amplitude within the period of the second voltage signal; And / or, predicting the zero-crossing time based on the time corresponding to the target amplitude includes: The time after a preset interval following the time corresponding to the target amplitude is taken as the zero-crossing time.

5. The method according to any one of claims 1-4, characterized in that, The motor module includes a series-wound motor; And / or, controlling the operating state of the motor module based on the zero-crossing detection result includes: Each time a zero-crossing point of the first voltage signal is detected, the motor module is controlled to enter the first state, and the state switching time is determined based on the time when the zero-crossing point is detected. At the state switching time, the motor module is controlled to enter the second state, where one of the first state and the second state is the start of operation and the other is the end of operation.

6. A motor control circuit, characterized in that, The motor control circuit includes: A receiving circuit, comprising a motor module and a receiving end for wirelessly powering the motor module, wherein the motor module is connected to the receiving end; A sampling circuit is used to sample the voltage signal at the receiving end; A zero-crossing detection circuit is used to perform zero-crossing detection on the voltage signal output by the sampling circuit to obtain the zero-crossing detection result; The control module is used to control the motor module to perform the initial start after power-on, and to control the working state of the motor module based on the zero-crossing detection result output by the zero-crossing detection circuit after the initial start. Specifically, the voltage signal output by the sampling circuit after the initial startup of the motor module is the first voltage signal, and the voltage signal output by the sampling circuit before the initial startup of the motor module is the second voltage signal. The control module is also connected to the output terminal of the sampling circuit. The control module performs the initial startup of the motor module after power-on by controlling the motor module to perform the initial startup specifically by: using the second voltage signal to predict the zero-crossing time of the first voltage signal, and controlling the motor module to perform the initial startup based on the zero-crossing time.

7. The circuit according to claim 6, characterized in that, Both the first voltage signal and the second voltage signal are periodic signals; the control module's execution of predicting the zero-crossing time of the first voltage signal using the second voltage signal specifically includes: determining the time corresponding to the target amplitude within the period of the second voltage signal; predicting the zero-crossing time based on the time corresponding to the target amplitude, wherein the zero-crossing time is the time corresponding to the zero-crossing point within the period of the first voltage signal.

8. The circuit according to claim 6, characterized in that, The sampling circuit includes a voltage divider resistor, a sampling resistor, and a first filter circuit. The first filter circuit is connected in parallel with the sampling resistor. The first end of the voltage divider resistor serves as the sampling terminal and is connected to the receiving circuit. The first end of the sampling resistor is connected to the second end of the voltage divider resistor and serves as the output terminal of the sampling circuit. The second end of the sampling resistor is grounded; and / or, The zero-crossing detection circuit is a comparator circuit. The first input terminal of the comparator circuit is connected to the output terminal of the sampling circuit, the second input terminal of the comparator circuit is grounded, and the output terminal of the comparator circuit serves as the output terminal of the zero-crossing detection circuit.

9. The circuit according to claim 8, characterized in that, The comparison circuit is a comparator; or, the comparison circuit includes a first resistor, a second resistor, and a transistor, wherein the emitter of the transistor serves as the second input terminal, the collector of the transistor serves as the output terminal, and is connected to the power supply through the second resistor, the base of the transistor is connected to one end of the first resistor, and the other end of the first resistor serves as the first input terminal.

10. The circuit according to claim 6, characterized in that, The receiving end circuit also includes a rectifier circuit, and the motor module is connected to the receiving end through the rectifier circuit; Wherein, the sampling terminal of the sampling circuit is connected to the end of the rectifier circuit that is connected to the motor module; or, the motor control circuit further includes a first rectifier diode and a second rectifier diode, one end of the first rectifier diode and one end of the second rectifier diode are respectively connected to the two ends of the receiving end, and the other ends of the first rectifier diode and the other ends of the second rectifier diode are both connected to the sampling terminal of the sampling circuit.

11. The circuit according to claim 10, characterized in that, The receiving circuit also includes a second filter circuit, which is connected in parallel with the motor module to the first DC connection terminal and the second DC connection terminal of the rectifier circuit.

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