A motor control device and method

Abstract

The application discloses a motor control device and a method thereof, relates to the technical field of motor control, and is used for controlling motor work. In view of the problem that current motor control devices cannot be reduced in size and lightened due to the existence of large electrolytic capacitors, the motor control device is provided. A zero-crossing detection module can detect the wave crest and wave trough of a driving voltage, so that a controller can control motor work by adjusting output current according to the waveform of the driving voltage and motor current sampled by a current detection module, and the control function of the motor is realized. Specifically, the current of the large electrolytic capacitor scheme is divided into the wave crest, so that the control device works at the wave crest and does not work at the wave trough, thereby replacing the function of the large electrolytic capacitor in the circuit. Therefore, the size and weight of the motor control device are not affected by the electrolytic capacitor, and the motor control device can be further lightened.

Description

Technical Field

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

[0002] With the continuous development of power electronics technology, the performance of electronic products such as motor control devices is becoming increasingly powerful, and correspondingly, user demands are also constantly increasing. Currently, users' requirements for motor control devices mainly focus on the following aspects: high integration and small size, long battery life, high power, high reliability, high efficiency, and long lifespan.

[0003] Current high-voltage brushless products are often accompanied by large electrolytic capacitors. Due to the size and weight of the large electrolytic capacitors, this design means that the motor control device cannot be made very small or very light.

[0004] Therefore, those skilled in the art urgently need a motor control device to solve the problem that current motor control devices cannot be reduced in size and made lighter due to the presence of large electrolytic capacitors. Summary of the Invention

[0005] The purpose of this application is to provide a motor control device and method that solves the problem that current motor control devices cannot be reduced in size and made lighter due to the presence of large electrolytic capacitors.

[0006] To solve the above-mentioned technical problems, this application provides a motor control device, including: a controller, a drive module, a current detection module, a power supply module, and a zero-crossing detection module;

[0007] The drive module is connected to the controller and the motor, and is used to control the motor speed according to the control signals sent by the controller.

[0008] The current detection module is connected to the drive module and the controller to sample the motor current;

[0009] The power module connects to the AC power supply and controller to convert AC power into DC power to provide the drive voltage;

[0010] The zero-crossing detection module is connected to the power supply module and controller to detect the peaks and troughs of the drive voltage;

[0011] The controller is used to control the commutation time of the motor based on the signal returned by the zero-crossing detection module, and to control the motor speed based on the signal returned by the current detection module.

[0012] Preferably, it also includes a position detection module connected to the controller and the drive module;

[0013] The position detection module includes: a first resistor, a second resistor, a third resistor, a fourth resistor, a fifth resistor, a sixth resistor, a seventh resistor, an eighth resistor, and a ninth resistor;

[0014] Each phase of the motor's three-phase voltage is grounded through a series connection of a first resistor and a second resistor, a series connection of a third resistor and a fourth resistor, and a series connection of a fifth resistor and a sixth resistor. The common terminal of the first resistor and the second resistor is connected to the first terminal of the seventh resistor, the common terminal of the third resistor and the fourth resistor is connected to the first terminal of the eighth resistor, the common terminal of the fifth resistor and the sixth resistor is connected to the first terminal of the ninth resistor, and the second terminals of the seventh resistor, the eighth resistor, and the ninth resistor are connected to form a center point.

[0015] The controller is connected to the common terminal of the first and second resistors, the common terminal of the third and fourth resistors, the common terminal of the fifth and sixth resistors, and the common terminal of the seventh, eighth, and ninth resistors, respectively. It is used to determine the position by comparing the voltage of each single-phase voltage divider with the voltage at the center point, so as to control the commutation of the motor.

[0016] Preferably, the current detection module includes: a sampling resistor and an RC filter circuit;

[0017] The first end of the sampling resistor is connected to the drive module and then to the controller through an RC filter circuit. The second end of the sampling resistor is grounded.

[0018] Preferably, the power module includes: a rectifier bridge, a DC-DC step-down chip, and an LDO;

[0019] The rectifier bridge is connected to the AC power supply and the DC-DC step-down chip. The DC-DC step-down chip is connected to the LDO, and the voltage output by the LDO is used as the drive voltage.

[0020] Preferably, the zero-crossing detection module includes: a tenth resistor, an eleventh resistor, a twelfth resistor, a Zener diode, and a first capacitor;

[0021] The neutral wire of the AC power supply is grounded through the tenth, eleventh, and twelfth resistors connected in series. The tenth resistor is connected to the neutral wire, the twelfth resistor is grounded, and the grounding terminal is connected to the negative output terminal of the rectifier bridge. The Zener diode and the first capacitor are connected in parallel across the twelfth resistor.

[0022] The controller is connected to the common terminal of the eleventh resistor, the twelfth resistor, the Zener diode, and the first capacitor to detect high and low levels in order to distinguish the peaks and troughs of the AC current.

[0023] Preferably, the zero-crossing detection module further includes: a thirteenth resistor and a fourteenth resistor;

[0024] The first end of the thirteenth resistor is connected to the live wire of the AC power supply, the second end of the thirteenth resistor is connected to the first end of the fourteenth resistor, and the second end of the fourteenth resistor is connected to the negative output terminal of the rectifier bridge.

[0025] Preferably, it also includes a temperature detection module connected to the controller;

[0026] The temperature detection module includes: a negative temperature coefficient thermistor, a fifteenth resistor, and a second capacitor;

[0027] The first terminal of the fifteenth resistor is connected to the driving voltage, and the second terminal of the fifteenth resistor is connected to the first terminal of the negative temperature coefficient thermistor; the second terminal of the negative temperature coefficient thermistor is grounded; the second capacitor is connected in parallel across the negative temperature coefficient thermistor.

[0028] The controller is connected to the common terminal of the negative temperature coefficient thermistor, the fifteenth resistor, and the second capacitor.

[0029] Preferably, it also includes a voltage detection module connected to the power module and the controller;

[0030] The voltage detection module includes: a sixteenth resistor, a seventeenth resistor, and a third capacitor;

[0031] The first terminal of the sixteenth resistor is connected to the positive output terminal of the rectifier bridge, and the second terminal of the sixteenth resistor is connected to the first terminal of the seventeenth resistor; the second terminal of the seventeenth resistor is grounded; the third capacitor is connected in parallel across the seventeenth resistor.

[0032] The controller is connected to the common terminal of the sixteenth resistor, the seventeenth resistor, and the third capacitor.

[0033] Preferably, the motor is a brushless motor.

[0034] To address the aforementioned technical problems, this application also provides a motor control method applied to a motor control device, wherein the motor control device includes a controller, a drive module, a current detection module, a power supply module, and a zero-crossing detection module; the drive module is connected to the controller and the motor; the current detection module is connected to the drive module and the controller; the power supply module is connected to an AC power source and the controller; the zero-crossing detection module is connected to the power supply module and the controller; including:

[0035] The controller receives the drive voltage waveform information detected by the zero-crossing detection module and the current signal sampled by the current detection module;

[0036] The controller modulates and outputs a PWM signal to the drive module based on the drive voltage waveform information and the current signal, so as to control the drive module to output constant current to the motor.

[0037] Preferred options also include:

[0038] The controller determines the average current of the current AC cycle and the real-time current at the current moment through the current detection module;

[0039] When the average current is greater than the first threshold and the real-time current is less than the second threshold, determine whether the motor speed is less than the third threshold.

[0040] If it is less than the fourth threshold, then when the real-time current is greater than the fourth threshold, the duty cycle of the PWM signal output by the controller decreases, and when the real-time current is not greater than the fourth threshold, the duty cycle of the PWM signal output by the controller increases.

[0041] If it is not less than, then determine whether the motor speed is less than the fifth threshold. If it is, then when the real-time current is greater than the sixth threshold, the duty cycle of the PWM signal output by the controller decreases, and when the real-time current is not greater than the sixth threshold, the duty cycle of the PWM signal output by the controller increases.

[0042] Among them, the first threshold is greater than the sixth threshold, and the fifth threshold is greater than the third threshold.

[0043] Preferred options also include:

[0044] When the average current is greater than the first threshold for a period of time exceeding the first preset duration, the fourth threshold decreases; when the average current is less than the first threshold for a period of time exceeding the first preset duration, the fourth threshold increases.

[0045] When the average current is greater than the seventh threshold for more than the second preset duration, the sixth threshold decreases; when the average current is less than the seventh threshold for more than the second preset duration, the sixth threshold increases.

[0046] The fourth threshold is greater than the seventh threshold.

[0047] This application provides a motor control device that uses a zero-crossing detection module to detect the peaks and troughs of the driving voltage. This allows the controller to adjust the output current based on the waveform of the driving voltage and the motor current sampled by the current detection module, thereby controlling the motor's operation and achieving motor control. Specifically, this device distributes the current from the large electrolytic capacitor solution to the peaks, allowing the control device to perform work during peaks and not during troughs, thus replacing the function of the large electrolytic capacitor in the circuit. Since no large electrolytic capacitor is needed, the size and weight of the motor control device are not affected by the electrolytic capacitor, further achieving weight reduction. Simultaneously, this electrolytic capacitor-free design eliminates the need for electrolytic capacitors and relays, freeing the entire motor control device from the limitations imposed by electrolytic capacitors and relays, and better meeting users' requirements for the lifespan of the motor control device.

[0048] The motor control method provided in this application corresponds to the above-mentioned device and has the same effect. Attached Figure Description

[0049] To more clearly illustrate the embodiments of this application, the accompanying drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0050] Figure 1 A structural diagram of a motor control device provided by the present invention;

[0051] Figure 2 A circuit diagram of a current detection module provided by the present invention;

[0052] Figure 3 A circuit diagram of a power supply module provided by the present invention;

[0053] Figure 4 A circuit diagram of a zero-crossing detection module provided by the present invention;

[0054] Figure 5 A circuit diagram of a position detection module provided by the present invention;

[0055] Figure 6 A circuit diagram of a temperature detection module provided by the present invention;

[0056] Figure 7 A circuit diagram of a voltage detection module provided by the present invention;

[0057] Figure 8 A flowchart of a motor control method provided by the present invention;

[0058] Figure 9 A flowchart of another motor control method provided by the present invention;

[0059] Figure 10 A structural diagram of another motor control device provided by the present invention.

[0060] Figure 11 This invention provides a structural diagram of a motor control system. Detailed Implementation

[0061] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of this application.

[0062] The core of this application is to provide a motor control device and method.

[0063] To enable those skilled in the art to better understand the present application, the present application will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0064] With the continuous development of technology, users' requirements for products are also constantly increasing. For example, for motor control devices, users' current needs are mainly focused on high integration, small size, long battery life, high power, high reliability, high efficiency, and long life.

[0065] In terms of battery life and power, low-voltage products on the market require very high current to achieve high power, which leads to severe heat generation issues. Therefore, high-voltage designs are more commonly used. Furthermore, DC battery packs also have insufficient battery life. Using AC input as the power source solves the problems of low battery life and low power, while also reducing heat generation. Therefore, most motor control devices on the market currently employ high-voltage AC designs.

[0066] However, the design scheme using high-voltage AC is often accompanied by large electrolytic capacitors. Because large electrolytic capacitors are inherently large in size and weight, the presence of large electrolytic capacitors determines that the size of the motor control device cannot be very small, and the weight cannot be very light. This is not conducive to the lightweighting of the motor control device, and thus cannot well meet the needs of users.

[0067] Meanwhile, the design scheme of large electrolytic capacitors also usually uses relays. It is easy to know that the lifespan of electrolytic capacitors and relays is not very high compared with other components in motor control devices. This limits the lifespan of motor control devices due to the electrolytic capacitors and relays, and cannot well meet the user's requirements for product lifespan.

[0068] Therefore, finding a design scheme for an electrolysis-free motor control device is a problem that urgently needs to be solved by those skilled in the art. This application provides a motor control device 110 to address the above problem, such as... Figure 1 As shown, it includes: controller 111, drive module 112, current detection module 113, power supply module 114 and zero-crossing detection module 115;

[0069] The drive module 112 is connected to the controller 111 and the motor 130, and is used to control the speed of the motor 130 according to the control signal sent by the controller 111; the current detection module 113 is connected to the drive module 112 and the controller 111, and is used to sample the current of the motor 130; the power supply module 114 is connected to the AC power supply 120 and the controller 111, and is used to convert AC power into DC power to provide drive voltage; the zero-crossing detection module 115 is connected to the power supply module 114 and the controller 111, and is used to detect the peak and trough of the drive voltage; the controller 111 is used to control the commutation time of the motor 130 according to the signal returned by the zero-crossing detection module 115, and to control the operation of the motor 130 according to the signal returned by the current detection module 113.

[0070] It should be noted that, Figure 1 This illustration only shows a schematic diagram of a motor control device 110 provided in this application and does not constitute a limitation on the motor control device 110 provided in this application. The motor control device 110 may have more than Figure 1 More or fewer components, at the same time Figure 1 The connections shown are not exhaustive; for example, there is the connection between the current detection module 113 and the drive module 112 to sample the motor current. Figure 1 Due to space limitations, it is not shown in the figure. The specific structure and connection relationship of the motor control device 110 shall be subject to the text description.

[0071] It is easy to understand that the controller 111 can be implemented by a device with control function, such as a microcontroller unit (MCU), a central processing unit (CPU), a complex programmable logic device (CPLD), etc. However, considering the size requirements of the motor control device in practical applications, an MCU is generally selected as the controller 111 of the motor control device 110.

[0072] One possible implementation of the drive module 112 may consist of a drive resistor, a drive chip, and an insulated gate bipolar transistor (IGBT) or a metal-oxide-semiconductor field-effect transistor (MOSFET). After receiving a signal from the MCU, the drive module 112 drives the switching of the IGBT / MOSFET to control the speed of the motor 130.

[0073] The current detection module 113 is used to detect the current of the motor 130. By sampling the current of the motor 130 and returning it to the MCU, the MCU can control the speed of the motor 130 in real time according to the current operating status of the motor 130. This embodiment provides a preferred implementation of the current detection module 113, such as... Figure 2 As shown, the current detection module 113 includes: a sampling resistor R0 and an RC filter circuit;

[0074] The first end of the sampling resistor R0 is connected to the drive module 112 (i.e., VGND) and is connected to the controller 111 (i.e., Isen) through the RC filter circuit. The second end of the sampling resistor R0 is grounded.

[0075] RC filter circuit: where R represents resistance and C represents capacitance, the RC filter circuit is a filter circuit composed of resistors and capacitors.

[0076] Similarly, this embodiment also provides a preferred solution for the implementation of the power module 114, such as... Figure 3 As shown, the power module 114 includes: a rectifier bridge, a DC-DC step-down chip, and an LDO;

[0077] The rectifier bridge is connected to the AC power supply 120V and the DC-DC step-down chip. The DC-DC step-down chip is connected to the LDO, and the voltage output by the LDO is used as the drive voltage.

[0078] LDO stands for low dropout regulator, which is a type of low dropout linear regulator.

[0079] Wherein, ACL is the live wire of AC power supply 120V, ACL is the neutral wire of AC power supply 120V, and P+ is the positive output terminal of the rectifier bridge.

[0080] And, a preferred embodiment of the zero-crossing detection module 115 is as follows: Figure 4 As shown, it includes: tenth resistor R10, eleventh resistor R11, twelfth resistor R12, Zener diode D1 and first capacitor C1;

[0081] The neutral wire of AC power supply 120 is grounded through the tenth resistor R10, the eleventh resistor R11 and the twelfth resistor R12 connected in series. The tenth resistor R10 is connected to the neutral wire, the twelfth resistor R12 is grounded, and the grounding terminal is connected to the negative output terminal (terminal 4 of D2) of rectifier bridge D2. The Zener diode and the first capacitor C1 are connected in parallel across the twelfth resistor R12.

[0082] The controller 111 is connected to the common terminal (ZERO) of the eleventh resistor R11, the twelfth resistor R12, the Zener diode and the first capacitor C1, and is used to detect high and low levels to distinguish the peaks and troughs of the AC current.

[0083] Specifically, the ZERO terminal should be high at the peak of the AC current and low at the trough of the AC current. Based on this, the controller 111 can determine the location of the AC current peak and trough, as well as identify the periodic frequency of the AC current.

[0084] Furthermore, based on the above embodiments, this embodiment also provides a preferred solution for the zero-crossing detection module 115, similarly as described above. Figure 4 As shown, the zero-crossing detection module 115 also includes: a thirteenth resistor R13 and a fourteenth resistor R14;

[0085] The first end of the thirteenth resistor R13 is connected to the live wire of AC power supply 120. The second end of the thirteenth resistor R13 is connected to the first end of the fourteenth resistor R14. The second end of the fourteenth resistor R14 is connected to the negative output terminal of rectifier bridge D2.

[0086] By adding the thirteenth resistor R13 and the fourteenth resistor R14, the zero-point signal (i.e., the level signal at the ZERO terminal) can be kept from floating when the rectifier diode D1 is not turned on, thereby making the zero-point signal more accurate and beneficial to the control of motor 130.

[0087] In summary, this application provides a motor control device that utilizes a zero-crossing detection module to determine the peak and trough positions of AC current, allowing the MCU to adjust its output at the corresponding locations, thus replacing the role of large electrolytic capacitors in traditional motor control device designs. The current detection module samples the motor current, enabling the controller to understand the motor's current operating condition and perform corresponding control operations to achieve motor control functions. Since the motor control device provided in this application does not require large electrolytic capacitors (an electrolytic-free solution), its size and weight are not limited by large electrolytic capacitors, allowing for better weight reduction. In one possible implementation, the zero-crossing detection module is implemented using only voltage divider resistors, capacitors, and rectifier diodes, resulting in more controllable size and relatively lighter weight, better meeting user requirements for the size and integration of the motor control device. Furthermore, the lifespan of the motor control device using the aforementioned electrolytic-free solution is not affected by large electrolytic capacitors and relays, ensuring a longer lifespan.

[0088] In current motor control devices, Hall effect sensors are typically used to determine the motor phase, which is then controlled by the controller to perform commutation operations. However, this design with Hall effect sensors also has certain drawbacks. Since the controller needs to communicate with the Hall effect board via data cables (usually five wires), if one cable fails, the entire motor will malfunction, potentially failing to start or even burning out, indicating insufficient reliability. Furthermore, this Hall effect solution requires Hall effect wires and three Hall effect sensors, resulting in relatively high costs, which contradicts practical requirements.

[0089] To address the above problems, this embodiment provides a preferred design scheme without Hall effect sensors, such as... Figure 1 As shown, the motor control device 110 described above also includes a position detection module 116 connected to the controller 111 and the drive module 112;

[0090] Position detection module 116, for example Figure 5 As shown, it includes: first resistor R1, second resistor R2, third resistor R3, fourth resistor R4, fifth resistor R5, sixth resistor R6, seventh resistor R7, eighth resistor R8 and ninth resistor R9;

[0091] Each phase (U, V, W) of the three-phase voltage of motor 130 is grounded through a series connection of first resistor R1 and second resistor R2, a series connection of third resistor R3 and fourth resistor R4, and a series connection of fifth resistor R5 and sixth resistor R6. The common terminal (HA) of first resistor R1 and second resistor R2 is connected to the first terminal of seventh resistor R7, the common terminal (HB) of third resistor R3 and fourth resistor R4 is connected to the first terminal of eighth resistor R8, the common terminal (HC) of fifth resistor R5 and sixth resistor R6 is connected to the first terminal of ninth resistor R9, and the second terminals of seventh resistor R7, eighth resistor R8 and ninth resistor R9 are connected to form a center point (STR).

[0092] The controller 111 is connected to the common terminal (HA) of the first resistor R1 and the second resistor R2, the common terminal (HB) of the third resistor R3 and the fourth resistor R4, the common terminal (HC) of the fifth resistor R5 and the sixth resistor R6, and the common terminal (STR) of the seventh resistor R7, the eighth resistor R8 and the ninth resistor R9, respectively. It is used to determine the position by comparing the voltage of each single phase (HA, HB, HC) with the center point voltage (STR) in order to control the commutation of the motor 130.

[0093] In a Hall sensor design, the Hall sensor returns a series of signals to determine the position, such as "101". In this design, a similar signal can be obtained by comparing HA, HB, HC and STR. For example, when HA is greater than STR, the return value is "1"; when HB is less than STR, the return value is "0"; when HC is greater than STR, the return value is "1", thus obtaining the signal "101". This replaces the function of the Hall sensor to determine the position, and the controller 111 can use this to control the commutation of the motor 130.

[0094] Furthermore, among the main user requirements for the motor control device 110 listed above, there are also requirements regarding efficiency, with the requirement that efficiency be as high as possible. Therefore, this embodiment provides a preferred implementation: the motor 130 is selected as a brushless motor.

[0095] Compared to series motors and brushed motors, brushless motors are maintenance-free, have no carbon brushes, have a long lifespan, and are highly efficient, making them more suitable for practical engineering needs.

[0096] This embodiment provides a preferred solution for a motor control device without Hall effect sensors. By constructing a center point and comparing it with the voltage of each phase, the voltage position is determined, thereby completing the commutation action of the motor. This replaces the traditional Hall sensor, eliminating the need for Hall wires and Hall boards. This saves costs and also reduces the risk of the motor failing to commutate due to a problem with any Hall wire, which could lead to starting failure or even burnout. This improves the reliability of the motor control device.

[0097] Furthermore, this embodiment also provides a preferred implementation scheme, such as... Figure 1 As shown, the motor control device 110 described above also includes a temperature detection module 117 connected to the controller 111;

[0098] Temperature detection module 117 Figure 6 As shown, it includes: Negative Temperature Coefficient (NTC) thermistors. NTC The fifteenth resistor R15 and the second capacitor C2;

[0099] The first terminal of the fifteenth resistor R15 is connected to the driving voltage VCC, and the second terminal of the fifteenth resistor R15 is connected to the negative temperature coefficient thermistor R. NTC The first terminal is connected; negative temperature coefficient thermistor R NTC The second terminal is grounded; the second capacitor C2 is connected in parallel with the negative temperature coefficient thermistor R. NTC Both ends;

[0100] Controller 111 and negative temperature coefficient thermistor R NTCConnect the fifteenth resistor R15 and the common terminal (NTC) of the second capacitor C2.

[0101] Through the negative temperature coefficient thermistor R NTC The characteristic of resistance changing with temperature can be understood by using a negative temperature coefficient thermistor R... NTC The temperature is set at the desired location, and the voltage value at the NTC is used to determine whether the motor 130 temperature is normal. This is easily understood by considering the negative temperature coefficient thermistor R... NTC The placement of the negative temperature coefficient thermistor R should be determined according to actual needs. Those skilled in the art can adjust the setting based on actual operating conditions. NTC It is set at an appropriate position on the motor 130, so this embodiment will not be described in detail here.

[0102] In addition, this embodiment also provides a preferred implementation scheme, such as... Figure 1 As shown, the motor control device 110 described above also includes a voltage detection module 118 connected to the power supply module 114 and the controller 111;

[0103] Voltage detection module 118, for example Figure 7 As shown, it includes: the sixteenth resistor R16, the seventeenth resistor R17, and the third capacitor C3;

[0104] The first end of the sixteenth resistor R16 is connected to the positive output terminal (P+) of the rectifier bridge D2, and the second end of the sixteenth resistor R16 is connected to the first end of the seventeenth resistor R17; the second end of the seventeenth resistor R17 is grounded; the third capacitor C3 is connected in parallel across the seventeenth resistor R17.

[0105] The controller 111 is connected to the common terminal (VOL) of the sixteenth resistor R16, the seventeenth resistor R17 and the third capacitor C3.

[0106] The voltage detection module 118 divides the voltage P+ after rectifier bridge D2 through the sixteenth resistor R16 and the seventeenth resistor R17, thereby detecting the voltage at VOL through the controller 111 to determine whether there is undervoltage.

[0107] It is easy to understand that when overheating or undervoltage problems occur, the controller 111 can issue an alarm through devices such as indicator lights, buzzers or displays to prompt maintenance personnel to troubleshoot the fault in a timely manner.

[0108] The preferred solution provided in this embodiment achieves the detection of motor temperature and undervoltage by adding a temperature detection module and a voltage detection module, thereby providing a more accurate and detailed judgment of the motor's operating condition. When the motor has overheating or undervoltage problems, it can be detected in time, thus prompting maintenance personnel to troubleshoot and eliminate the problem in a timely manner, ensuring the safe operation of the motor to the greatest extent.

[0109] Regarding the motor control device provided in the above embodiments, this application also provides a control method corresponding to the above device, applied to the motor control device described in the above embodiments, such as... Figure 8 As shown, it includes:

[0110] S201: The controller acquires the drive voltage waveform information detected by the zero-crossing detection module and the current signal sampled by the current detection module;

[0111] S202: The controller modulates and outputs a PWM signal to the drive module based on the drive voltage waveform information and the current signal, so as to control the drive module to output constant current to the motor.

[0112] As described in the above embodiments, in traditional electrolysis schemes, electrical energy provides power to do work during the trough. The motor control device provided in this application distributes this portion of the current to the peak to do work, thereby replacing the effect of a large electrolytic capacitor. Generally, in the actual control of a motor, in order to ensure the smooth operation of the motor, the motor control device needs to output a constant current, that is, to spread the pulse width modulation (PWM) signal at the peak and trough of the AC current (i.e., to modulate the PWM signal). However, in practical applications, there may be a situation where the output is constant but the load continues to increase. In this case, it is necessary to increase the duty cycle of the PWM signal, which will result in the PWM signal being fully on during the trough.

[0113] The motor control method provided in this embodiment, applied to the motor control device described in the above embodiment, allows the controller to acquire waveform information of the driving voltage through a zero-crossing detection module. This allows the controller to determine whether the current AC current is at a peak or trough. Furthermore, based on the motor current signal acquired by the current sampling module, a PWM signal is spread to control the drive module to output a constant current to drive the motor, meeting practical engineering requirements. Since this method is applied to a motor control device without electrolytic capacitors, the absence of large electrolytic capacitors effectively reduces the size and weight of the motor control device, better meeting users' demands for high integration and lightweight motor control products.

[0114] After a soft start, the motor is in an unloaded state. In this state, the motor control device can either fully activate the PWM or modulate the motor to maintain a constant speed; this application does not impose any restrictions on this. However, when the motor is under high-current, heavy-load conditions, current limiting is necessary; otherwise, excessive instantaneous current at AC peaks could damage the IGBT / MOSFET of the drive module. Therefore, this embodiment provides a preferred implementation scheme, such as... Figure 9 As shown, the above method also includes:

[0115] S301: The controller determines the average current of the current AC cycle and the real-time current at the current moment through the current detection module.

[0116] S302: Determine whether the average current is greater than the first threshold and the real-time current is less than the second threshold. If so, proceed to step S303.

[0117] S303: Determine whether the motor speed is less than the third threshold. If yes, proceed to step S304; otherwise, proceed to step S305.

[0118] It is easy to understand that obtaining the motor speed is well known to those skilled in the art, and there are already mature hardware devices or methods for obtaining the motor speed. Moreover, how to obtain the motor speed is not the focus of this application, so it will not be described in detail here.

[0119] S304: When the real-time current is greater than the fourth threshold, the duty cycle of the PWM signal output by the controller decreases; when the real-time current is not greater than the fourth threshold, the duty cycle of the PWM signal output by the controller increases.

[0120] S305: Determine if the motor speed is less than the fifth threshold. If so, proceed to step S306.

[0121] S306: When the real-time current is greater than the sixth threshold, the duty cycle of the PWM signal output by the controller decreases; when the real-time current is not greater than the sixth threshold, the duty cycle of the PWM signal output by the controller increases.

[0122] Among them, the first threshold is greater than the sixth threshold, and the fifth threshold is greater than the third threshold.

[0123] The control mode implemented in step S304 is a constant current output mode, referred to as the first constant current mode. In this mode, based on the fourth threshold and the settings for the rate of increase and decrease when the real-time current is greater than or less than the fourth threshold, the motor control device can output a constant current at a preset magnitude. Similarly, the control mode implemented in step S305 is also a constant current output mode, referred to as the second constant current mode. In one possible application scenario shown in this embodiment, the current output in the first constant current mode is greater than the current output in the second constant current mode.

[0124] It is easy to see that the judgment condition of step S302 is the condition for entering constant current mode. When the condition of step S302 is not met, the constant current mode is exited. The judgment condition of step S305 is the condition for entering the second constant current mode. When the condition is not met, the method is exited. However, considering that this method is a real-time and continuous process, the negative branches of steps S302 and S305 can be to return to step S301, that is, to re-determine whether the motor is under high current heavy load. And when step S306 is completed, the method is also re-performed, that is, returning to step S301.

[0125] Furthermore, to better improve the constant current control effect of the above-mentioned constant current mode, this embodiment also provides a preferred implementation scheme, such as... Figure 9 As shown, the above method also includes:

[0126] S307: When the average current is greater than the first threshold for a period of time exceeding the first preset duration, the fourth threshold decreases; when the average current is less than the first threshold for a period of time exceeding the first preset duration, the fourth threshold increases.

[0127] S308: When the average current is greater than the seventh threshold for a period of time exceeding the second preset duration, the sixth threshold decreases; when the average current is less than the seventh threshold for a period of time exceeding the second preset duration, the sixth threshold increases.

[0128] The fourth threshold is greater than the seventh threshold.

[0129] The preferred solution provided in this embodiment can achieve the following: when entering constant current mode, if the motor load continues to increase, the PWM modulation at the trough will reduce the motor speed to a very low speed, making it easier for staff to detect abnormalities in the motor in a timely manner and take corresponding measures to troubleshoot the fault.

[0130] Similarly, when the above situation occurs, the alarm device connected to the controller can also remind the operation and maintenance personnel to reduce the power used, otherwise the motor may burn out.

[0131] In a preferred embodiment, by adjusting the fourth and sixth thresholds, the current output of the motor control device in constant current mode becomes more stable. When the load continues to increase even when the motor control device enters constant current mode, the fourth and sixth thresholds used to modulate the PWM duty cycle will change accordingly, thereby maintaining the motor speed at a very low level. By clearly distinguishing the motor operating conditions from the normal state, this alerts the staff to detect motor abnormalities, thereby improving the timeliness of troubleshooting and resolving motor faults, protecting motor lifespan, and reducing the risks and losses caused by motor faults in actual engineering projects.

[0132] In the above embodiments, a motor control method has been described in detail. This application also provides an embodiment corresponding to a motor control device. It should be noted that this application describes the embodiment of the device from two perspectives: one is based on the functional modules, and the other is based on the hardware.

[0133] From the perspective of functional modules, this embodiment provides a motor control device, such as... Figure 10 As shown, it includes:

[0134] The acquisition module 41 is used to enable the controller to acquire the drive voltage waveform information detected by the zero-crossing detection module and the current signal sampled by the current detection module.

[0135] The PWM module 42 is used to enable the controller to modulate and output a PWM signal to the drive module based on the drive voltage waveform information and the current signal, so as to control the drive module to output a constant current to the motor.

[0136] Preferred options also include:

[0137] The current acquisition module is used to enable the controller to determine the average current of the current AC cycle and the real-time current at the current moment through the current detection module.

[0138] The mode determination module is used to determine whether the motor speed is less than the third threshold when the average current is greater than the first threshold and the real-time current is less than the second threshold. If yes, the first constant current module is triggered; otherwise, the second constant current module is triggered.

[0139] The first constant current module is used to reduce the duty cycle of the PWM signal output by the controller when the real-time current is greater than the fourth threshold, and to increase the duty cycle of the PWM signal output by the controller when the real-time current is not greater than the fourth threshold.

[0140] The second constant current module is used to determine whether the motor speed is less than the fifth threshold. If so, when the real-time current is greater than the sixth threshold, the duty cycle of the PWM signal output by the controller decreases, and when the real-time current is not greater than the sixth threshold, the duty cycle of the PWM signal output by the controller increases. Among them, the first threshold is greater than the sixth threshold, and the fifth threshold is greater than the third threshold.

[0141] Since the embodiments of the apparatus and the embodiments of the method correspond to each other, please refer to the description of the embodiments of the method for the embodiments of the apparatus, which will not be repeated here.

[0142] Figure 11 A structural diagram of a motor control system provided in another embodiment of this application is shown below. Figure 11 As shown, a motor control system includes: a memory 50 for storing computer programs;

[0143] The processor 51 is used to execute a computer program to implement the steps of a motor control method as described in the above embodiment.

[0144] The processor 51 may include one or more processing cores, such as a quad-core processor or an octa-core processor. The processor 51 may be implemented using at least one of the following hardware forms: Digital Signal Processor (DSP), Field-Programmable Gate Array (FPGA), or Programmable Logic Array (PLA). The processor 51 may also include a main processor and a coprocessor. The main processor, also known as the Central Processing Unit (CPU), is used to process data in the wake-up state; the coprocessor is a low-power processor used to process data in the standby state. In some embodiments, the processor 51 may integrate a Graphics Processing Unit (GPU), which is responsible for rendering and drawing the content to be displayed on the screen. In some embodiments, the processor 51 may also include an Artificial Intelligence (AI) processor, which is used to handle computational operations related to machine learning.

[0145] The memory 50 may include one or more computer-readable storage media, which may be non-transitory. The memory 50 may also include high-speed random access memory and non-volatile memory, such as one or more disk storage devices or flash memory devices. In this embodiment, the memory 50 is used to store at least the following computer program 501, which, after being loaded and executed by the processor 51, is capable of implementing the relevant steps of a motor control method disclosed in any of the foregoing embodiments. In addition, the resources stored in the memory 50 may also include an operating system 502 and data 503, and the storage method may be temporary or permanent storage. The operating system 502 may include Windows, Unix, Linux, etc. The data 503 may include, but is not limited to, a motor control method.

[0146] In some embodiments, a motor control system may further include a display screen 52, an input / output interface 53, a communication interface 54, a power supply 55, and a communication bus 56.

[0147] Those skilled in the art will understand that Figure 11 The structure shown does not constitute a limitation on a motor control system and may include more or fewer components than shown.

[0148] This application provides a motor control system, including a memory and a processor. When the processor executes a program stored in the memory, it can implement the following method: a motor control method.

[0149] Finally, this application also provides an embodiment corresponding to a computer-readable storage medium. The computer-readable storage medium stores a computer program, which, when executed by a processor, implements the steps described in the above method embodiments.

[0150] It is understood that if the methods in the above embodiments are implemented as software functional units and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of this application, in essence, or the part that contributes to the prior art, or all or part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and executes all or part of the steps of the methods described in the various embodiments of this application. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0151] The foregoing has provided a detailed description of a motor control device, method, system, and medium provided in this application. The various embodiments in the specification are described in a progressive manner, with each embodiment focusing on its differences from other embodiments. Similar or identical parts between embodiments can be referred to interchangeably. For the devices disclosed in the embodiments, since they correspond to the methods disclosed in the embodiments, the descriptions are relatively simple; relevant parts can be referred to in the method section. It should be noted that those skilled in the art can make various improvements and modifications to this application without departing from the principles of this application, and these improvements and modifications also fall within the protection scope of the claims of this application.

[0152] It should also be noted that, in this specification, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

Claims

1. A motor control device, characterized in that, The application relates to a motor control system, which comprises a controller, a driving module, a current detection module, a power module and a zero-crossing detection module. The driving module is connected with the controller and a motor, and is used for controlling the motor speed according to the control signal sent by the controller. The current detection module is connected with the driving module and the controller, and is used for sampling the current of the motor. The power module is connected with an alternating current power supply and the controller, and is used for converting alternating current into direct current to provide a driving voltage. The zero-crossing detection module is connected with the power module and the controller, and is used for detecting the wave crest and wave trough of the driving voltage. The controller is used for controlling the time of motor commutation according to the signal returned by the zero-crossing detection module, and controlling the motor speed according to the signal returned by the current detection module. The controller is further used for: determining the average current of the current alternating current period and the real-time current at the current moment through the current detection module; when the average current is greater than a first threshold value and the real-time current is less than a second threshold value, judging whether the motor speed is less than a third threshold value; if yes, when the real-time current is greater than a fourth threshold value, the duty cycle of the PWM signal output by the controller is reduced, and when the real-time current is not greater than the fourth threshold value, the duty cycle of the PWM signal output by the controller is increased; if no, judging whether the motor speed is less than a fifth threshold value, if yes, when the real-time current is greater than a sixth threshold value, the duty cycle of the PWM signal output by the controller is reduced, and when the real-time current is not greater than the sixth threshold value, the duty cycle of the PWM signal output by the controller is increased; wherein the first threshold value is greater than the sixth threshold value, the fifth threshold value is greater than the third threshold value, and the second threshold value is greater than the fourth threshold value and the sixth threshold value; when the time during which the average current is greater than the first threshold value exceeds a first preset time length, the fourth threshold value is reduced, and when the time during which the average current is less than the first threshold value exceeds the first preset time length, the fourth threshold value is increased; when the time during which the average current is greater than a seventh threshold value exceeds a second preset time length, the sixth threshold value is reduced, and when the time during which the average current is less than the seventh threshold value exceeds the second preset time length, the sixth threshold value is increased; wherein the fourth threshold value is greater than the seventh threshold value. The application further comprises a position detection module connected with the controller and the driving module.

2. The motor control device according to claim 1, characterized by The position detection module comprises a first resistor, a second resistor, a third resistor, a fourth resistor, a fifth resistor, a sixth resistor, a seventh resistor, an eighth resistor and a ninth resistor. ​ Each phase of the three-phase voltage of the motor is grounded through the first resistor and the second resistor in series, the third resistor and the fourth resistor in series, and the fifth resistor and the sixth resistor in series, respectively; the common end of the first resistor and the second resistor is connected with the first end of the seventh resistor, the common end of the third resistor and the fourth resistor is connected with the first end of the eighth resistor, and the common end of the fifth resistor and the sixth resistor is connected with the first end of the ninth resistor; the second ends of the seventh resistor, the eighth resistor and the ninth resistor are connected, and a center point is led out; The controller is connected with the common end of the first resistor and the second resistor, the common end of the third resistor and the fourth resistor, the common end of the fifth resistor and the sixth resistor, and the common end of the seventh resistor, the eighth resistor and the ninth resistor, respectively, for judging the position by comparing each single-phase voltage with the voltage of the center point, so as to control the commutation of the motor.

3. The motor control device of claim 1, wherein The current detection module comprises a sampling resistor and an RC filter circuit; The first end of the sampling resistor is connected with the driving module and connected with the controller through the RC filter circuit, and the second end of the sampling resistor is grounded.

4. The motor control device of claim 1, wherein The power module comprises a rectifier bridge, a DC-DC step-down chip and an LDO; The rectifier bridge is connected with the AC power supply and the DC-DC step-down chip, the DC-DC step-down chip is connected with the LDO, and the voltage output by the LDO is used as the driving voltage.

5. The motor control device of claim 4, wherein The zero-crossing point detection module comprises a tenth resistor, an eleventh resistor, a twelfth resistor, a voltage stabilizing tube and a first capacitor; The zero line of the AC power supply is grounded through the tenth resistor, the eleventh resistor and the twelfth resistor connected in series, wherein the tenth resistor is connected with the zero line, the twelfth resistor is grounded, and the grounded end is connected with the negative output end of the rectifier bridge; the voltage stabilizing tube and the first capacitor are connected in parallel across the twelfth resistor, respectively; The controller is connected with the common end of the eleventh resistor, the twelfth resistor, the voltage stabilizing tube and the first capacitor, for detecting high and low levels to distinguish the wave crest and the wave trough of the AC power supply.

6. The motor control device of claim 5, wherein The zero-crossing point detection module further comprises a thirteenth resistor and a fourteenth resistor; The first end of the thirteenth resistor is connected with the live wire of the AC power supply, the second end of the thirteenth resistor is connected with the first end of the fourteenth resistor, and the second end of the fourteenth resistor is connected with the negative output end of the rectifier bridge.

7. The motor control device of claim 1, wherein Further comprising a temperature detection module connected with the controller; The temperature detection module comprises a negative temperature coefficient thermistor, a fifteenth resistor and a second capacitor; The first end of the fifteenth resistor is connected with the driving voltage, the second end of the fifteenth resistor is connected with the first end of the negative temperature coefficient thermistor; the second end of the negative temperature coefficient thermistor is grounded; and the second capacitor is connected in parallel across the negative temperature coefficient thermistor; The controller is connected with the common end of the negative temperature coefficient thermistor, the fifteenth resistor and the second capacitor.

8. The motor control device of claim 4, wherein Further comprising a voltage detection module connected with the power module and the controller; The voltage detection module comprises a sixteenth resistor, a seventeenth resistor and a third capacitor; The first end of the sixteenth resistor is connected with the positive output end of the rectifier bridge, the second end of the sixteenth resistor is connected with the first end of the seventeenth resistor, the second end of the seventeenth resistor is grounded, and the third capacitor is connected in parallel across the seventeenth resistor; The controller is connected with the common end of the sixteenth resistor, the seventeenth resistor and the third capacitor.

9. The motor control device according to any one of claims 1 to 8, characterized by The motor is a brushless motor.

10. A method of controlling an electric machine, characterized by The motor control device comprises a controller, a driving module, a current detection module, a power module and a zero-crossing detection module; the driving module is connected with the controller and a motor; the current detection module is connected with the driving module and the controller; the power module is connected with an alternating current power supply and the controller; the zero-crossing detection module is connected with the power module and the controller; comprising: The controller acquires driving voltage waveform information detected by the zero-crossing detection module and a current signal sampled by the current detection module; The controller modulates and outputs a PWM signal to the driving module according to the driving voltage waveform information and the current signal, so as to control the driving module to output constant current to the motor; The controller determines the average current of the current alternating current period and the real-time current at the current moment through the current detection module; When the average current is greater than a first threshold value and the real-time current is less than a second threshold value, it is determined whether the rotating speed of the motor is less than a third threshold value; If yes, when the real-time current is greater than a fourth threshold value, the duty cycle of the PWM signal output by the controller is reduced, and when the real-time current is not greater than the fourth threshold value, the duty cycle of the PWM signal output by the controller is increased; If no, it is determined whether the rotating speed of the motor is less than a fifth threshold value, and if yes, when the real-time current is greater than a sixth threshold value, the duty cycle of the PWM signal output by the controller is reduced, and when the real-time current is not greater than the sixth threshold value, the duty cycle of the PWM signal output by the controller is increased; The first threshold value is greater than the sixth threshold value, the fifth threshold value is greater than the third threshold value, the second threshold value is greater than the fourth threshold value and the sixth threshold value; When the time during which the average current is greater than the first threshold value exceeds a first preset time length, the fourth threshold value is reduced, and when the time during which the average current is less than the first threshold value exceeds the first preset time length, the fourth threshold value is increased; When the time during which the average current is greater than a seventh threshold value exceeds a second preset time length, the sixth threshold value is reduced, and when the time during which the average current is less than the seventh threshold value exceeds the second preset time length, the sixth threshold value is increased; The fourth threshold value is greater than the seventh threshold value.

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