Motor drive method and system

Abstract

The application discloses a motor driving method and system. In the technical scheme of the application, the state of a bidirectional thyristor is controlled by outputting pulse width modulation signals (a first pulse width modulation signal, a second pulse width modulation signal, a third pulse width modulation signal and a fourth pulse width modulation signal) based on the direction of alternating current and the position signals (a first position signal, a second position signal, a third position signal and a fourth position signal) of a rotor in a single-phase synchronous motor by using a single-chip microcomputer, so as to start and continuously drive the single-phase synchronous motor. Compared with the starting and driving mode of multiple IGBT power devices, the mode of starting and driving the single-phase synchronous motor only by using the bidirectional thyristor can reduce the cost, the required computing power and the requirement for the single-chip microcomputer, and further reduce the cost.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of motor driving, in particular to a motor driving method and system. BACKGROUND

[0002] In some household appliances, in order to solve the problems of short service life of brush motor, electric spark and noise during use, single-phase synchronous motor is widely used in some household appliances due to its advantages of high efficiency, low noise, long service life and low cost.

[0003] At present, when driving the single-phase synchronous motor, the alternating current for driving the single-phase synchronous motor needs to be rectified and filtered by a rectifier bridge, the external signal is collected by a single-chip microcomputer, and then a sine wave is simulated through complex mathematical operation, and a pulse width modulation (PWM) signal is output to a high-voltage IGBT (Insulated Gate Bipolar Transistor) power device, and then the single-phase synchronous motor is controlled, wherein a plurality of IGBT power devices need to be set, resulting in high cost, and the required computing power is high when controlling multiple IGBT power devices, and the requirement for the single-chip microcomputer is also relatively high, so that the cost is further increased.

[0004] Therefore, the prior art still needs to be improved and developed. SUMMARY

[0005] In view of the above problems of the prior art, the purpose of the present application is to provide a motor driving method and system to solve the problem that in the prior art, when driving the single-phase synchronous motor, multiple IGBT power devices need to be set, resulting in high cost, and the required computing power is high when controlling multiple IGBT power devices, and the requirement for the single-chip microcomputer is also relatively high, so that the cost is further increased.

[0006] The technical scheme adopted by the present application to solve the technical problems is to provide a motor driving method, which drives a single-phase synchronous motor connected to alternating current based on a bidirectional thyristor and a zero-crossing detection module, a position detection sensor is arranged in the single-phase synchronous motor for detecting the position of the rotor in the single-phase synchronous motor, the zero-crossing detection module is connected to the alternating current connected to the single-phase synchronous motor, and the motor driving method comprises:

[0007] Step A: obtaining a first position signal of the rotor in the single-phase synchronous motor, the first position signal being a position signal of the rotor detected by the position detection sensor before starting the single-phase synchronous motor;

[0008] Step B: outputting a first pulse width modulation signal to the bidirectional thyristor based on the positive half cycle of the alternating current;

[0009] Step C: obtaining a second position signal of the rotor, the second position signal being a position signal of the rotor detected by the position detection sensor after the first pulse width modulation signal is output to the bidirectional thyristor;

[0010] wherein, when a first difference between the first position signal and the second position signal is not in a first range, the single-phase synchronous motor is successfully started, and the first range is a preset range;

[0011] when the first difference between the first position signal and the second position signal is in the first range, steps D and E are performed;

[0012] Step D: outputting a second pulse width modulation signal to the bidirectional thyristor based on a negative half cycle of the alternating current;

[0013] Step E: obtaining a third position signal of the rotor, the third position signal being a position signal of the rotor detected by the position detection sensor after the second pulse width modulation signal is output to the bidirectional thyristor;

[0014] wherein, when a second difference between the third position signal and the first position signal is not in the first range, the single-phase synchronous motor is successfully started;

[0015] when the second difference between the first position signal and the third position signal is in the first range, the step B is performed until the single-phase synchronous motor is successfully started;

[0016] after the single-phase synchronous motor is started, step F is performed;

[0017] the step F: obtaining a fourth position signal of the rotor every first time interval, the fourth position signal being a position signal of the rotor detected by the position detection sensor every first time interval after the single-phase synchronous motor is successfully started;

[0018] when the fourth position signal is in an increasing state and the alternating current is in a positive half cycle, a third pulse width modulation signal is generated to the bidirectional thyristor to drive the single-phase synchronous motor to continue rotating, and when the fourth position signal is in a decreasing state and the alternating current is in a negative half cycle, a fourth pulse width modulation signal is generated to the bidirectional thyristor to drive the single-phase synchronous motor to continue rotating.

[0019] Further provided in the application, after the single-phase synchronous motor is started, the motor driving method further comprises:

[0020] obtaining a time value of a zero-crossing signal in an increasing or decreasing process of the fourth position signal;

[0021] determining a second difference between the acquired time value of the zero-crossing signal and a time value of a last acquired zero-crossing signal of the fourth position signal after each time the time value of the zero-crossing signal of the fourth position signal is acquired;

[0022] determining an operating frequency of the single-phase synchronous motor based on the second difference, and when the operating frequency is not within the second range, the single-phase synchronous motor is operating abnormally.

[0023] In a further aspect of the application, the second range is greater than one half of the frequency of the AC power and less than twice the frequency of the AC power.

[0024] In a further aspect of the application, the method further comprises, before step A:

[0025] determining that the single-phase synchronous motor is connected to AC power, and when the single-phase synchronous motor is connected to AC power, performing step A after a second time.

[0026] In a further aspect of the application, the second time is in the range of 2-5 cycles of the AC power.

[0027] In a further aspect of the application, the AC power is 110V AC power at 60Hz, or the AC power is 220V AC power at 50Hz.

[0028] In a further aspect of the application, the first time is in the range of 200-300μs.

[0029] The application also provides a system for driving a single-phase synchronous motor connected to AC power, the single-phase synchronous motor being provided with a position detection sensor for detecting a position of a rotor in the single-phase synchronous motor, the system comprising:

[0030] a triac connected in series in a connection path of the single-phase synchronous motor to the AC power;

[0031] a zero-crossing detection module connected to the AC power connected to the single-phase synchronous motor;

[0032] a single-chip microcomputer linked to the position detection sensor, the zero-crossing detection module and the output triac, the single-chip microcomputer being configured to perform step A, the step A being acquiring a first position signal of the rotor in the single-phase synchronous motor, the first position signal being a position signal of the rotor detected by the position detection sensor before the single-phase synchronous motor is started;

[0033] is further configured to perform step B, wherein the step B is outputting a first pulse width modulation signal to the triac based on a positive half cycle of the alternating current;

[0034] is further configured to perform step C, wherein the step C is obtaining a second position signal of the rotor, the second position signal being a position signal of the rotor detected by the position detection sensor after the first pulse width modulation signal is output to the triac;

[0035] wherein, when a first difference between the first position signal and the second position signal is not in a first range, the single-phase synchronous motor is successfully started, and the first range is a preset range;

[0036] when the first difference between the first position signal and the second position signal is in the first range, the single-chip microcomputer is further configured to perform steps D and E;

[0037] the step D is outputting a second pulse width modulation signal to the triac based on a negative half cycle of the alternating current;

[0038] the step E is obtaining a third position signal of the rotor, the third position signal being a position signal of the rotor detected by the position detection sensor after the second pulse width modulation signal is output to the triac;

[0039] wherein, when a second difference between the third position signal and the first position signal is not in a first range, the single-phase synchronous motor is successfully started;

[0040] when the second difference between the first position signal and the third position signal is in the first range, the single-chip microcomputer is further configured to perform from the step B until the single-phase synchronous motor is successfully started;

[0041] after the single-phase synchronous motor is started, the single-chip microcomputer is further configured to perform step F, wherein the step F is obtaining a fourth position signal of the rotor every interval of a first time, the fourth position signal being a position signal of the rotor detected by the position detection sensor every interval of the first time after the single-phase synchronous motor is successfully started;

[0042] when the fourth position signal is in an increasing state and the alternating current is in a positive half cycle, a third pulse width modulation signal is generated to the triac to drive the single-phase synchronous motor to continue rotating, and when the fourth position signal is in a decreasing state and the alternating current is in a negative half cycle, a fourth pulse width modulation signal is generated to the triac to drive the single-phase synchronous motor to continue rotating.

[0043] The single-chip microcomputer is further configured to obtain a time value of a zero-crossing signal in the process of increment or decrement of the fourth position signal after the single-phase synchronous motor is started.

[0044] The single-chip microcomputer is further configured to establish a second difference between time values of two adjacent zero-crossing signals based on the zero-crossing signal in the process of increment or decrement of the fourth position signal.

[0045] The single-chip microcomputer is further configured to determine an operating frequency of the single-phase synchronous motor based on the second difference, and the single-phase synchronous motor is abnormal when the operating frequency is not in the second range.

[0046] The motor driving system further comprises:

[0047] When the single-phase synchronous motor is connected to an alternating current, the single-chip microcomputer starts from the step A after a second time.

[0048] The present application has the following beneficial effects:

[0049] In the starting and driving of the single-phase synchronous motor, the state of the bidirectional thyristor is controlled by the single-chip microcomputer based on the direction of the alternating current and the position signals (first position signal, second position signal, third position signal, and fourth position signal) of the rotor of the single-phase synchronous motor to output pulse width modulation signals (first pulse width modulation signal, second pulse width modulation signal, third pulse width modulation signal, and fourth pulse width modulation signal) to start and continue to drive the single-phase synchronous motor. Compared with the starting and driving mode of multiple IGBT power devices, the starting and driving mode of the single-phase synchronous motor by only the bidirectional thyristor reduces the cost, the required computing power, and the requirements for the single-chip microcomputer, further reducing the cost. BRIEF DESCRIPTION OF DRAWINGS

[0050] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or prior art description. Obviously, the drawings in the following description are only some embodiments of the present application, and those skilled in the art can obtain other drawings according to the structures shown in these drawings without creative labor.

[0051] Figure 1 is a flowchart of the motor driving method of the present application.

[0052] Figure 2 is a part of the curve in the rotor position signal diagram collected by the position detection sensor in an embodiment of the present application.

[0053] Figure 3This is a graph of alternating current in one embodiment of the present invention.

[0054] Figure 4 This is a schematic block diagram of the motor drive system of the present invention.

[0055] Figure 5 This is a detailed circuit diagram of the zero-crossing detection module in one embodiment of the present invention.

[0056] The markings in the attached diagram are as follows: 100, microcontroller; 200, zero-crossing detection module; 300, position detection sensor; 400, single-phase synchronous motor; Q1, bidirectional thyristor. Detailed Implementation

[0057] To provide a clearer understanding of the technical features, objectives, and effects of this invention, specific embodiments are now described in detail with reference to the accompanying drawings. In the following description, it should be understood that the orientations or positional relationships indicated by terms such as "front," "rear," "upper," "lower," "left," "right," "longitudinal," "horizontal," "vertical," "horizontal," "top," "bottom," "inner," "outer," "head," and "tail" are based on the orientations or positional relationships shown in the accompanying drawings, and are constructed and operated in a specific orientation. They are only for the convenience of describing this technical solution and do not indicate that the device or element referred to must have a specific orientation; therefore, they should not be construed as limitations on this invention.

[0058] like Figure 4 , Figure 1 As shown, the present invention provides a motor drive system for driving a single-phase synchronous motor 400 connected to AC power. The single-phase synchronous motor 400 is provided with a position detection sensor 300 for detecting the rotor position of the single-phase synchronous motor 400. The AC power can be 110V / 60HZ AC power or 220V / 50HZ AC power.

[0059] The motor drive system may include a bidirectional thyristor Q1, a zero-crossing detection module 200, and a microcontroller 100. The microcontroller 100 is connected to the bidirectional thyristor Q1 and the zero-crossing detection module 200. When the single-phase synchronous motor 400 is connected to AC power, the live wire of the AC power is connected to the power supply terminal corresponding to the live wire in the single-phase synchronous motor 400, and the neutral wire is connected to the power supply terminal corresponding to the neutral wire in the single-phase synchronous motor 400 via the bidirectional thyristor Q1. When the bidirectional thyristor Q1 is turned on, the neutral wire is connected to the power supply terminal corresponding to the neutral wire in the single-phase synchronous motor 400. The zero-crossing detection module 200 is connected to the AC power and is used to detect the direction of the AC power (whether the AC power is outputting during the positive half-cycle or the negative half-cycle during operation).

[0060] The microcontroller 100 is used to execute steps 101, 102 and 103.

[0061] Step 101 is to obtain a first position signal of the rotor in the single-phase synchronous motor 400, and the first position signal is a position signal of the rotor detected by the position detection sensor 300 before the single-phase synchronous motor 400 starts.

[0062] Step 102 is to output a first pulse width modulation signal to the bidirectional thyristor Q1 based on the positive half cycle of the alternating current after the first position signal is obtained.

[0063] Step 103 is to obtain a second position signal of the rotor, and the second position signal is a position signal of the rotor detected by the position detection sensor 300 after the first pulse width modulation signal is output to the bidirectional thyristor Q1.

[0064] Wherein, when a first difference between the first position signal and the second position signal is not in a first range, the single-phase synchronous motor 400 starts successfully, and the first range is a preset range which is preset and stored in the single-chip microcomputer 100; when the first difference between the first position signal and the second position signal is in the first range, the single-chip microcomputer 100 is further used to execute step 104 and step 105.

[0065] Step 104 is to output a second pulse width modulation signal to the bidirectional thyristor Q1 based on the negative half cycle of the alternating current.

[0066] Step 105 is to obtain a third position signal of the rotor, and the third position signal is a position signal of the rotor detected by the position detection sensor 300 after the second pulse width modulation signal is output to the bidirectional thyristor Q1.

[0067] Wherein, when a second difference between the third position signal and the first position signal is not in the first range, the single-phase synchronous motor 400 starts successfully; when the second difference between the first position signal and the third position signal is in the first range, the single-chip microcomputer 100 is further used to execute from step 102 until the single-phase synchronous motor 400 starts successfully.

[0068] Wherein, after the single-phase synchronous motor 400 starts, the single-chip microcomputer 100 is further used to execute step 106.

[0069] Step 106 is to obtain a fourth position signal of the rotor every interval of a first time, and the fourth position signal is a position signal of the rotor detected by the position detection sensor 300 every interval of the first time in a running process after the single-phase synchronous motor 400 starts successfully; when the fourth position signal is in an increasing state and the alternating current is in a positive half cycle, a third pulse width modulation signal is generated to the bidirectional thyristor Q1 to drive the single-phase synchronous motor 400 to continue rotating, and when the fourth position signal is in a decreasing state and the alternating current is in a negative half cycle, a fourth pulse width modulation signal is generated to the bidirectional thyristor Q1 to drive the single-phase synchronous motor 400 to continue rotating.

[0070] Specifically, when driving the single-phase synchronous motor 400, it is necessary to start the single-phase synchronous motor 400 first, and then further continue to drive the single-phase synchronous motor 400 after the single-phase synchronous motor 400 is started.

[0071] Wherein, when the single-phase synchronous motor 400 is started, the direction of the alternating current connected to the single-phase synchronous motor 400 is determined by the zero-crossing detection module 200, and further, the position signal of the rotor of the single-phase synchronous motor 400 before starting (the first position signal) is detected by the position detection module and transmitted to the single-chip microcomputer 100. After the single-chip microcomputer 100 obtains the first position signal, it outputs a first pulse signal to the bidirectional thyristor Q1 based on the positive half cycle of the alternating current. At this time, the bidirectional thyristor Q1 is in a conducting state, and the alternating current flows to the single-phase synchronous motor 400. After the first pulse signal is output to the bidirectional thyristor Q1, the position signal of the rotor of the single-phase synchronous motor 400 after the first pulse signal is output to the thyristor (the second position signal) is detected again by the position detection module. After the second position signal is obtained, the single-chip microcomputer 100 further calculates and determines the first difference between the first position signal and the second position signal according to the first position signal and the second position signal. When the first difference is within a first range (indicating that the position of the rotor of the single-phase synchronous motor 400 has not changed), it indicates that the single-phase synchronous motor 400 has not started successfully. When the first difference is not within the first range (indicating that the position of the rotor of the single-phase synchronous motor 400 has changed), it indicates that the single-phase synchronous motor 400 has started successfully.

[0072] The first range is pre-set in the single-chip microcomputer 100. The purpose of setting the first range is that the position detection module outputs an electrical signal after detecting the position signal of the rotor, which is transmitted to the single-chip microcomputer 100 for analog-to-digital conversion inside the single-chip microcomputer 100. Therefore, it is necessary to set a first range to avoid misjudgment due to the error of the analog-to-digital converter inside the single-chip microcomputer 100 during the analog-to-digital conversion process, i.e., it is necessary to set a first range to determine whether the position of the rotor of the single-phase synchronous motor 400 has changed, which is not affected by the error of the analog-to-digital converter. When the first range is set, the specific setting range is related to the conversion accuracy of the analog-to-digital converter inside the single-chip microcomputer 100, i.e., if the position of the rotor of the single-phase synchronous motor 400 changes accurately, for example, when the analog-to-digital converter inside the single-chip microcomputer 100 has a precision of 12, the first range is set to be between 10-20 digital quantities.

[0073] Wherein, when the single-phase synchronous motor 400 is started, the first difference between the first position signal and the second position signal may be less than the minimum value within the first range, or the first difference between the first position signal and the second position signal may be greater than the maximum value within the first range, at this time, it indicates that the single-phase synchronous motor 400 has started successfully.

[0074] After the first pulse signal is output to the single-phase synchronous motor 400 in the positive half cycle of the alternating current, if the single-phase synchronous motor 400 fails to start successfully, the second pulse signal needs to be output to the bidirectional thyristor Q1 based on the negative half cycle of the alternating current. At this time, the bidirectional thyristor Q1 is in a conductive state, and the alternating current flows to the single-phase synchronous motor 400. After the second pulse signal is output to the bidirectional thyristor Q1, the position signal of the rotor of the single-phase synchronous motor 400 after the second pulse signal is output to the thyristor (third position signal) is detected by the position detection module. After the third position signal is acquired, the single-chip microcomputer 100 further calculates and determines a second difference value between the first position signal and the third position signal according to the first position signal and the third position signal. When the second difference value is in the first range, it indicates that the single-phase synchronous motor 400 fails to start successfully. When the second difference value is not in the first range, it indicates that the single-phase synchronous motor 400 starts successfully.

[0075] When the second pulse signal is output to the bidirectional thyristor Q1, a certain time delay can be set after it is determined that the single-phase synchronous motor 400 fails to start successfully before the second pulse signal is output to the bidirectional thyristor Q1. For example, the time delay can be 2 ms, 3 ms, etc.

[0076] After the second pulse signal is output to the bidirectional thyristor Q1, if the single-phase synchronous motor 400 still fails to start successfully, the steps need to be re-executed from step 102 until the single-phase synchronous motor 400 starts successfully.

[0077] When the single-phase synchronous motor 400 is further driven to start successfully, the single-chip microcomputer 100 acquires the position signal of the rotor of the single-phase synchronous motor 400 (fourth position signal) every first time interval, and compares the last fourth position signal with the previous fourth position signal in the acquired fourth position signal. The comparison of the two (the last fourth position signal and the previous fourth position signal) fourth position signals determines whether the fourth position signal is in an increasing state or a decreasing state.

[0078] When the fourth position signal is in the increasing state and the alternating current is in the positive half cycle, the single-chip microcomputer 100 outputs a third pulse width modulation signal to the bidirectional thyristor Q1 to drive the single-phase synchronous motor 400 to continue rotating. When the fourth position signal is in the decreasing state and the alternating current is in the negative half cycle, the single-chip microcomputer 100 outputs a fourth pulse width modulation signal to the bidirectional thyristor Q1 to drive the single-phase synchronous motor 400 to continue rotating. When the positive half cycle of the alternating current and the N-pole position waveform of the permanent magnet in the single-phase synchronous motor 400 and the negative half cycle of the alternating current and the S-pole position waveform of the permanent magnet in the single-phase synchronous motor 400 overlap, the single-phase synchronous motor 400 has the highest efficiency and the lowest noise.

[0079] In the embodiment, when starting and driving the single-phase synchronous motor 400, the state of the bidirectional thyristor Q1 is controlled by the single-chip microcomputer 100 outputting pulse width modulation signals (first, second, third and fourth pulse width modulation signals) based on the direction of the alternating current and the position signals (first, second, third and fourth position signals) of the rotor of the single-phase synchronous motor 400, so as to start and continuously drive the single-phase synchronous motor 400. Compared with the starting and driving mode of multiple IGBT power devices, the starting and driving mode of the single-phase synchronous motor 400 by the bidirectional thyristor Q1 reduces the cost, the required computing power, and the requirements for the single-chip microcomputer 100, further reducing the cost.

[0080] In addition, when the bidirectional thyristor Q1 controls the switch, the bidirectional thyristor Q1 is turned on in the positive half cycle or the negative half cycle of the alternating current. Compared with the IGBT power device, the switching frequency is reduced, the switching loss is reduced, and because the internal resistance of the bidirectional thyristor Q1 is low, the loss and heat are reduced during the starting and continuous driving of the single-phase synchronous motor 400.

[0081] Further, as shown in FIG. 7, during the driving of the single-phase synchronous motor 400, the single-chip microcomputer 100 is further configured to perform steps 107, 108 and 109. Figure 1

[0082] Step 107 is to obtain the time value of the zero-crossing signal in the process of increment or decrement of the fourth position signal.

[0083] Step 108 is to determine the third difference value between the time value of the obtained zero-crossing signal and the time value of the last obtained zero-crossing signal after obtaining the time value of the zero-crossing signal each time.

[0084] Step 109 is to determine the running frequency of the single-phase synchronous motor 400 based on the third difference value. When the running frequency is not in the second range, the single-phase synchronous motor 400 is abnormal.

[0085] Specifically, during the operation of the single-phase synchronous motor 400, the curve formed by the position signal in one period is a sine wave curve. When the single-phase synchronous motor 400 operates normally, the running frequency of the single-phase synchronous motor 400 is in a range, and the running frequency of the single-phase synchronous motor 400 can be calculated by the third difference value between the time values corresponding to two zero-crossing signals in the curve formed by the fourth position signal detected by the position detection sensor 300. Specifically, the third difference value between the time values corresponding to two adjacent zero-crossing signals is a half cycle, and the running frequency of the single-phase synchronous motor 400 can be determined according to the relationship between the period and the frequency. ​

[0086] Therefore, according to the characteristics, the single-chip microcomputer 100 can obtain the time value of the zero-crossing signal in the increasing or decreasing process of the fourth position signal, and determine the third difference value between the time value of the obtained zero-crossing signal and the time value of the last obtained zero-crossing signal after obtaining the time value of the zero-crossing signal each time. The running frequency of the single-phase synchronous motor 400 is determined through the third difference value, and then whether the single-phase synchronous motor 400 is running normally (the single-phase synchronous motor 400 is locked or jittered) is determined according to the running frequency of the single-phase synchronous motor 400 determined by the single-phase synchronous motor 400.

[0087] In some embodiments, the second range is greater than one half of the frequency of the alternating current and less than twice the frequency of the alternating current.

[0088] In the present embodiment, when the alternating current is 110V / 60HZ alternating current, the second range is greater than 30HZ and less than 120HZ; when the alternating current is 220 / 50HZ alternating current, the second range is greater than 25HZ and less than 100HZ; wherein the second range can be stored in the single-chip microcomputer 100 in advance according to the frequency of the alternating current.

[0089] In some embodiments, before the single-chip microcomputer 100 performs step 101, it is also used to perform step 110.

[0090] Step 110 is to determine whether the single-phase synchronous motor 400 is connected to the alternating current. When the single-phase synchronous motor 400 is connected to the alternating current, the step 101 is performed after the second time.

[0091] Specifically, according to the characteristics of the bidirectional thyristor Q1, when the bidirectional thyristor Q1 is in the case of direct current, the bidirectional thyristor Q1 cannot automatically turn off. Therefore, before the single-chip microcomputer 100 performs step 101, it is determined that the single-phase synchronous motor 400 is connected to the alternating current, and after the single-chip microcomputer 100 determines that the single-phase synchronous motor 400 is connected to the alternating current, the single-chip microcomputer 100 starts to perform the above-mentioned step 101 after the second time. The purpose of setting the second time is to make the alternating current connected to the single-phase synchronous motor 400 in a stable working state, wherein the second time can be stored in the single-chip microcomputer 100 in advance.

[0092] In some embodiments, the range of the second time is 2-5 cycles of the alternating current.

[0093] In the present embodiment, the second time can be 3 cycles of the connected alternating current, and the second time can also be 2 cycles, 3.5 cycles, 4 cycles, etc. of the connected alternating current.

[0094] In some embodiments, the single-chip microcomputer 100 can be, but is not limited to, a chip with the model PY32F002AL15STU.

[0095] In some embodiments, the zero-crossing detection module 200 can be any circuit structure capable of achieving the above-mentioned functions in the prior art, which is not limited here. As shown in Figure 5 , it is a specific circuit structure diagram of the zero-crossing detection module 200 applicable to the motor driving system in the prior art.

[0096] In some embodiments, the position detection module can be a linear Hall sensor, which detects the position of the rotor in the single-phase synchronous motor 400 and outputs a position signal. The model of the linear Hall sensor can be AH602SU.

[0097] In some embodiments, the bidirectional thyristor Q1 can be, but is not limited to, the model RS405K-800B.

[0098] In some embodiments, as shown in Figure 1 , Figure 2 and Figure 3 , the present application also provides a motor driving method, which can be applied to the above-mentioned motor driving system. The motor driving method drives a single-phase synchronous motor connected to an alternating current based on a bidirectional thyristor and a zero-crossing detection module. The single-phase synchronous motor is provided with a position detection sensor for detecting the position of the rotor in the single-phase synchronous motor. The zero-crossing detection module is connected to the alternating current, and is used to detect the direction of the alternating current. The motor driving method comprises:

[0099] Step 101: obtaining a first position signal of the rotor in the single-phase synchronous motor, the first position signal being the position signal of the rotor detected by the position detection sensor before the single-phase synchronous motor starts;

[0100] Step 102: outputting a first pulse width modulation signal to the bidirectional thyristor based on the positive half cycle of the alternating current;

[0101] Step 103: obtaining a second position signal of the rotor, the second position signal being the position signal of the rotor detected by the position detection sensor after the first pulse width modulation signal is output to the bidirectional thyristor;

[0102] Wherein, when the first difference between the first position signal and the second position signal is not in the first range, the single-phase synchronous motor starts successfully, and the first range is a preset range;

[0103] When the first difference between the first position signal and the second position signal is in the first range, steps 104 and 105 are performed;

[0104] Step 104: outputting a second pulse width modulation signal to the bidirectional thyristor based on the negative half cycle of the alternating current;

[0105] Step 105: obtaining a third position signal of the rotor, the third position signal being a position signal of the rotor detected by the position detection sensor after the second pulse width modulation signal is output to the bidirectional thyristor;

[0106] wherein, when the second difference between the third position signal and the first position signal is not in the first range, the single-phase synchronous motor is started successfully;

[0107] when the second difference between the first position signal and the third position signal is in the first range, step 102 is executed until the single-phase synchronous motor is started successfully;

[0108] After the single-phase synchronous motor is started, step 106 is executed;

[0109] Step 106: obtaining a fourth position signal of the rotor every first time interval, the fourth position signal being a position signal of the rotor detected by the position detection sensor every first time interval after the single-phase synchronous motor is started successfully;

[0110] When the fourth position signal is in an increasing state and the alternating current is in a positive half cycle, a third pulse width modulation signal is generated to the bidirectional thyristor to drive the single-phase synchronous motor to continue rotating, and when the fourth position signal is in a decreasing state and the alternating current is in a negative half cycle, a fourth pulse width modulation signal is generated to the bidirectional thyristor to drive the single-phase synchronous motor to continue rotating.

[0111] Specifically, when driving the single-phase synchronous motor, the single-phase synchronous motor needs to be started first, and only after the single-phase synchronous motor is started can the single-phase synchronous motor be further driven.

[0112] wherein, when the single-phase synchronous motor is started, the direction of the alternating current connected to the single-phase synchronous motor is determined by the zero-crossing detection module, and the position signal of the rotor before the single-phase synchronous motor is started (the first position signal) is further detected by the position detection module and transmitted to the single-chip microcomputer. After the single-chip microcomputer obtains the first position signal, the single-chip microcomputer outputs a first pulse signal to the bidirectional thyristor based on the positive half cycle of the alternating current. At this time, the bidirectional thyristor is in a conducting state, and the alternating current flows to the single-phase synchronous motor. After the first pulse signal is output to the bidirectional thyristor, the position signal of the rotor after the first pulse signal is output to the bidirectional thyristor is detected again by the position detection module (the second position signal). After the second position signal is obtained, the single-chip microcomputer further calculates the first difference between the first position signal and the second position signal based on the first position signal and the second position signal. When the first difference is in the first range (indicating that the position of the rotor of the single-phase synchronous motor has not changed), it indicates that the single-phase synchronous motor has not been started successfully. When the first difference is not in the first range (indicating that the position of the rotor of the single-phase synchronous motor has changed), it indicates that the single-phase synchronous motor has been started successfully.

[0113] The first range is preset in the single-chip microcomputer. The purpose of setting the first range is that the position detection module outputs an electrical signal after detecting the position signal of the rotor. The electrical signal is transmitted to the single-chip microcomputer and then subjected to analog-digital conversion in the single-chip microcomputer. Therefore, a first range needs to be set to avoid misjudgment due to the error of the analog-digital converter in the single-chip microcomputer during the analog-digital conversion, that is, a first range needs to be set to determine whether the position of the rotor of the single-phase synchronous motor changes, and the range is not affected by the error of the analog-digital converter. When the first range is set, the specific setting range is related to the conversion accuracy of the analog-digital converter in the single-chip microcomputer, that is, if the position of the rotor of the single-phase synchronous motor changes, the position of the rotor of the single-phase synchronous motor can be accurately obtained, for example, when the analog-digital converter in the single-chip microcomputer has a 12-bit accuracy, the first range is set to be between 10 and 20 digital quantities.

[0114] When the single-phase synchronous motor is started, the first difference between the first position signal and the second position signal may be less than the minimum value in the first range, or the first difference between the first position signal and the second position signal may be greater than the maximum value in the first range. At this time, it indicates that the single-phase synchronous motor is successfully started.

[0115] After the first pulse signal is output to the single-phase synchronous motor during the positive half cycle of the alternating current, if the single-phase synchronous motor is not successfully started, the second pulse signal needs to be output to the bidirectional thyristor based on the negative half cycle of the alternating current. At this time, the bidirectional thyristor is in a conductive state, and the alternating current flows to the single-phase synchronous motor. After the second pulse signal is output to the bidirectional thyristor, the position signal of the rotor of the single-phase synchronous motor (the third position signal) is detected by the position detection module. After the third position signal is obtained, the single-chip microcomputer further calculates the second difference between the first position signal and the third position signal. When the second difference is in the first range, it indicates that the single-phase synchronous motor is not successfully started. When the second difference is not in the first range, it indicates that the single-phase synchronous motor is successfully started.

[0116] After the second pulse signal is output to the bidirectional thyristor, if the single-phase synchronous motor is not successfully started, the steps need to be re-executed from step 102 until the single-phase synchronous motor is successfully started.

[0117] When the single-phase synchronous motor is further driven after being successfully started, the single-chip microcomputer obtains the position signal of the rotor of the single-phase synchronous motor (the fourth position signal) every first time interval, and compares the last fourth position signal with the previous fourth position signal in the obtained fourth position signal. The comparison of the two (the last fourth position signal and the previous fourth position signal) fourth position signals determines whether the fourth position signal is in an increasing state or a decreasing state.

[0118] When the fourth position signal is in the increasing state and the alternating current is in the positive half cycle, the single-chip microcomputer outputs a third pulse width modulation signal to the bidirectional thyristor to drive the single-phase synchronous motor to continue rotating; when the fourth position signal is in the decreasing state and the alternating current is in the negative half cycle, the single-chip microcomputer outputs a fourth pulse width modulation signal to the bidirectional thyristor to drive the single-phase synchronous motor to continue rotating.

[0119] In the embodiment, when the single-phase synchronous motor is started and driven, the state of the bidirectional thyristor is controlled by the single-chip microcomputer based on the direction of the alternating current and the position signals (the first position signal, the second position signal, the third position signal, and the fourth position signal) of the rotor of the single-phase synchronous motor to output pulse width modulation signals (the first pulse width modulation signal, the second pulse width modulation signal, the third pulse width modulation signal, and the fourth pulse width modulation signal), so as to start and continuously drive the single-phase synchronous motor. Compared with the starting and driving mode of multiple IGBT power devices, the mode of starting and driving the single-phase synchronous motor only by the bidirectional thyristor reduces the cost, the required computing power, and the requirements on the single-chip microcomputer, and further reduces the cost.

[0120] After the single-phase synchronous motor is started, the motor driving method further includes:

[0121] Step 107: acquiring a time value of a zero-crossing signal of the fourth position signal in the increasing or decreasing process;

[0122] Step 108: determining a third difference value between the acquired time value of the zero-crossing signal and the time value of the last acquired zero-crossing signal of the fourth position signal after acquiring the time value of the zero-crossing signal of the fourth position signal each time;

[0123] Step 109: determining the running frequency of the single-phase synchronous motor based on the third difference value, and when the running frequency is not in the second range, the single-phase synchronous motor is abnormal. Details are described in the embodiment of the motor driving system based on the bidirectional thyristor, which will not be described here.

[0124] In some embodiments, the second range is greater than one-half of the frequency of the alternating current and less than twice the frequency of the alternating current. Details are described in the embodiment of the motor driving system based on the bidirectional thyristor, which will not be described here.

[0125] In some embodiments, the step 101 includes a step before the step 101:

[0126] Step 100: determine that the single-phase synchronous motor is connected to AC power, and when the single-phase synchronous motor is connected to AC power, start from step 101 after a second time. As described in the embodiment of the motor driving system based on triacs, which will not be repeated here.

[0127] In some embodiments, the second time ranges from 2 to 5 cycles of AC power. As described in the embodiment of the motor driving system based on triacs, which will not be repeated here.

[0128] In some embodiments, the first time ranges from 200 to 300 μs. As described in the embodiment of the motor driving system based on triacs, which will not be repeated here.

[0129] Here, it should be noted that the above description of the motor driving method embodiment is similar to the above description of the motor driving system embodiment, and has similar benefits as the above motor driving system. For technical details not disclosed in the motor driving method embodiment, please refer to the description of the motor driving system embodiment of the application for understanding.

[0130] In summary, the present application provides a motor driving method and system, which has the following beneficial effects:

[0131] When starting and driving the single-phase synchronous motor, the single-chip microcomputer outputs pulse width modulation signals (first, second, third and fourth pulse width modulation signals) based on the direction of AC power and the position signals (first, second, third and fourth position signals) of the rotor in the single-phase synchronous motor to control the state of the triac, so as to start and continue to drive the single-phase synchronous motor. Compared with the starting and driving mode of multiple IGBT power devices, the mode of starting and driving the single-phase synchronous motor only through the triac reduces the cost and the required computing power, and the requirements for the single-chip microcomputer are also reduced, further reducing the cost.

[0132] It can be understood that the above embodiments only express the preferred embodiments of the present application, which are described in detail and specifically, but cannot be understood as a limitation on the scope of the patent of the present application; It should be noted that for ordinary skilled persons in the art, the above technical features can be freely combined without departing from the concept of the present application, and some modifications and improvements can be made, which are within the scope of protection of the present application; Therefore, any equivalent transformation and modification within the scope of the claims of the present application shall be within the scope of the claims of the present application.

Claims

1. A motor driving method for driving a single-phase synchronous motor connected to an alternating current based on a bidirectional thyristor and a zero-crossing detection module, wherein a position detection sensor for detecting a rotor position in the single-phase synchronous motor is provided, and the zero-crossing detection module is connected to the alternating current to which the single-phase synchronous motor is connected, characterized in that, The motor driving method comprises: Step A: obtaining a first position signal of a rotor in the single-phase synchronous motor, the first position signal being a position signal of the rotor detected by the position detection sensor before starting of the single-phase synchronous motor; Step B: outputting a first pulse width modulation signal to the bidirectional thyristor based on a positive half cycle of the alternating current; Step C: obtaining a second position signal of the rotor, the second position signal being a position signal of the rotor detected by the position detection sensor after the first pulse width modulation signal is output to the bidirectional thyristor; wherein, when a first difference between the first position signal and the second position signal is not within a first range, the starting of the single-phase synchronous motor is successful, and the first range is a preset range; when the first difference between the first position signal and the second position signal is within the first range, steps D and E are performed; Step D: outputting a second pulse width modulation signal to the bidirectional thyristor based on a negative half cycle of the alternating current; Step E: obtaining a third position signal of the rotor, the third position signal being a position signal of the rotor detected by the position detection sensor after the second pulse width modulation signal is output to the bidirectional thyristor; wherein, when a second difference between the third position signal and the first position signal is not within the first range, the starting of the single-phase synchronous motor is successful; when the second difference between the first position signal and the third position signal is within the first range, the step B is performed until the starting of the single-phase synchronous motor is successful; after the starting of the single-phase synchronous motor, step F is performed; the step F: obtaining a fourth position signal of the rotor every interval of a first time, the fourth position signal being a position signal of the rotor detected by the position detection sensor every interval of the first time after the starting of the single-phase synchronous motor is successful; when the fourth position signal is in an increasing state and the alternating current is in a positive half cycle, a third pulse width modulation signal is generated to the bidirectional thyristor to drive the single-phase synchronous motor to continue rotating, and when the fourth position signal is in a decreasing state and the alternating current is in a negative half cycle, a fourth pulse width modulation signal is generated to the bidirectional thyristor to drive the single-phase synchronous motor to continue rotating.

2. The motor drive method according to claim 1, characterized by, after the starting of the single-phase synchronous motor, the motor driving method further comprises: obtaining a time value of a zero-crossing signal of the fourth position signal in an increasing or decreasing process; determining a third difference between the time value of the zero-crossing signal of the fourth position signal obtained and a time value of a zero-crossing signal of the fourth position signal obtained last time after the time value of the zero-crossing signal of the fourth position signal is obtained each time; determining a running frequency of the single-phase synchronous motor based on the third difference, and when the running frequency is not within a second range, the single-phase synchronous motor is running abnormally.

3. The motor drive method according to claim 2, characterized by, the second range being greater than one half of the frequency of the alternating current and less than twice the frequency of the alternating current.

4. The motor drive method according to claim 1, characterized by, before the step A, comprising: determining that the single-phase synchronous motor is connected to an AC power supply, and when the single-phase synchronous motor is connected to the AC power supply, starting from the step A after a second time.

5. The motor drive method according to claim 4, characterized by, The second time is in a range of 2-5 cycles of the AC power supply.

6. The motor drive method according to claim 5, characterized by, The AC power supply is 110V, 60HZ, or the AC power supply is 220V, 50HZ.

7. The motor drive method according to claim 1, characterized by, The first time is in a range of 200-300μs.

8. An electric motor drive system applying the electric motor drive method according to any one of claims 1 to 7, the system being used to drive a single-phase synchronous electric motor to which an alternating current is applied, the single-phase synchronous electric motor being provided with a position detection sensor for detecting a position of a rotor in the single-phase synchronous electric motor, characterized in that, The system comprises: a bidirectional thyristor connected in series to an input of the single-phase synchronous motor connected to the AC power supply; a zero-crossing detection module connected to the AC power supply connected to the single-phase synchronous motor; a single-chip microcomputer connected to the position detection sensor, the zero-crossing detection module and the bidirectional thyristor, the single-chip microcomputer being configured to execute the step A of obtaining a first position signal of a rotor in the single-phase synchronous motor, the first position signal being a position signal of the rotor detected by the position detection sensor before starting of the single-phase synchronous motor; the step B of outputting a first pulse width modulation signal to the bidirectional thyristor based on a positive half cycle of the AC power supply; the step C of obtaining a second position signal of the rotor, the second position signal being a position signal of the rotor detected by the position detection sensor after the first pulse width modulation signal is output to the bidirectional thyristor; wherein when a first difference between the first position signal and the second position signal is not in a first range, the single-phase synchronous motor is started successfully, and the first range is a preset range; when the first difference between the first position signal and the second position signal is in the first range, the single-chip microcomputer is further configured to execute the step D and the step E; the step D of outputting a second pulse width modulation signal to the bidirectional thyristor based on a negative half cycle of the AC power supply; the step E of obtaining a third position signal of the rotor, the third position signal being a position signal of the rotor detected by the position detection sensor after the second pulse width modulation signal is output to the bidirectional thyristor; wherein when a second difference between the third position signal and the first position signal is not in the first range, the single-phase synchronous motor is started successfully; when the second difference between the first position signal and the third position signal is in the first range, the single-chip microcomputer is further configured to execute the step B until the single-phase synchronous motor is started successfully; after the single-phase synchronous motor is started, the single-chip microcomputer is further configured to execute the step F of obtaining a fourth position signal of the rotor every first time, the fourth position signal being a position signal of the rotor detected by the position detection sensor every first time after the single-phase synchronous motor is started successfully. When the fourth position signal is in the increasing state and the alternating current is in the positive half cycle, a third pulse width modulation signal is generated to the bidirectional thyristor to drive the single-phase synchronous motor to continue rotating; when the fourth position signal is in the decreasing state and the alternating current is in the negative half cycle, a fourth pulse width modulation signal is generated to the bidirectional thyristor to drive the single-phase synchronous motor to continue rotating.

9. The motor drive system of claim 8, wherein, After the single-phase synchronous motor is started, the single-chip microcomputer is further configured to acquire a time value of a zero-crossing signal in an increasing or decreasing process of the fourth position signal; The single-chip microcomputer is further configured to determine a third difference value between time values of two adjacent zero-crossing signals based on the zero-crossing signal in the increasing or decreasing process of the fourth position signal. The single-chip microcomputer is further configured to determine a running frequency of the single-phase synchronous motor based on the third difference value, and when the running frequency is not in a second range, the single-phase synchronous motor is abnormal.

10. The motor drive system of claim 8, wherein, The motor driving system further comprises: When the single-phase synchronous motor is connected to the alternating current, after a second time, the single-chip microcomputer starts from the step A.

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