Brushless direct current motor control system, control method and intelligent dust collector

Abstract

The invention discloses a brushless direct current motor control system and method and an intelligent dust collector, and the method comprises the steps: obtaining the real-time rotating speed and real-time voltage of the operation of a brushless direct current motor, and the q-axis real-time current and d-axis real-time current in a rotating coordinate system according to the detected speed and position signals, voltage signals and current signals of the brushless direct current motor; calculating a q-axis reference current through a sliding mode control algorithm based on a rotating speed error between a given target rotating speed and a real-time rotating speed; d-axis reference current is calculated according to given target power and real-time voltage; adjusting the torque output of the brushless direct current motor according to the current error between the q-axis reference current and the q-axis real-time current; and adjusting the flux linkage of the brushless direct current motor according to the current error between the d-axis reference current and the d-axis real-time current. Therefore, the dynamic stability in the speed regulation process of the motor can be improved, the overshoot or buffeting phenomenon is avoided, and the operation experience of a user is improved.

Description

Technical Field

[0001] The present application relates to the technical field of vacuum cleaners, and in particular to a brushless DC motor control system, a control method and an intelligent vacuum cleaner. Background Art

[0002] As a household appliance for cleaning and hygiene, vacuum cleaners are usually used to remove dust from floors, carpets, walls, furniture and various gaps. Due to the different cleaning scenarios of the vacuum cleaner, such as whether the floor is flat, the amount of dust and garbage, whether the floor is carpeted, etc., there are different requirements for the suction provided by the vacuum cleaner. The suction of the vacuum cleaner is mainly adjusted by controlling the input power of the motor and the speed of the motor. Generally, the suction of the vacuum cleaner is adjusted by setting the gear button, but because the stroke in the entire speed regulation process is relatively short, the motor control system is prone to overshoot or jitter during speed regulation due to the large change in the motor running speed, which affects the user's operating experience. Therefore, it is necessary to provide an improved technical solution to overcome the above technical problems existing in the prior art. Summary of the invention

[0003] The purpose of this application is to provide a brushless DC motor control system, control method and intelligent vacuum cleaner, which can improve the dynamic stability of the motor during speed regulation, avoid overshoot or jitter, and enhance the user's operating experience.

[0004] To achieve the above objectives: In a first aspect, an embodiment of the present application provides a brushless DC motor control system, the system comprising a brushless DC motor, a voltage detection circuit, a current detection circuit, an inverter circuit, a back electromotive force detection circuit, a key detection circuit, a power management circuit and a micro control unit; wherein, The voltage detection circuit is used to detect the voltage signal of the brushless DC motor bus; The current detection circuit is used to detect the current signal of the brushless DC motor bus; The inverter circuit is used to invert the DC power output by the power module into the three-phase AC power required to drive the brushless DC motor according to the control signal output by the micro control unit; The back electromotive force detection circuit is used to detect the speed and position signals of the brushless DC motor; The key detection circuit is used to determine the preset gear information according to the key input signal; The power management circuit is used to convert the output voltage of the power module into the working voltage required by each circuit module; The micro control unit is used to generate a motor control signal through a sliding mode control algorithm based on the gear information, voltage signal, current signal, speed and position signal to control the operation of the brushless DC motor.

[0005] In one embodiment, the system also includes a voltage and current protection circuit and a temperature protection circuit; wherein the voltage and current protection circuit is used to compare the voltage signal and the current signal with a preset voltage threshold and current threshold respectively, and when the voltage threshold and / or current threshold are exceeded, the microcontroller unit is controlled to output an overvoltage and / or overcurrent protection signal; the temperature protection circuit is used to monitor the temperature of the brushless DC motor when it is working, and when the temperature of the brushless DC motor when it is working exceeds a preset temperature threshold, the microcontroller unit is controlled to output an overtemperature protection signal.

[0006] In one embodiment, the system further comprises a voltage stabilizing circuit, which is used to provide a stable power supply voltage so that the brushless DC motor and each circuit module can operate stably under different loads and power supply fluctuations.

[0007] In one embodiment, the system also includes a voice module and an information display module, wherein the voice module is used to receive an input voice signal and identify the gear information based on the voice signal; the information display module is used to display the speed information, voltage information, current information and power information of the brushless DC motor.

[0008] In a second aspect, an embodiment of the present application provides a brushless DC motor control method, which is applied to the brushless DC motor control system as described above, and the method includes: According to the detected speed and position signals, voltage signals and current signals of the brushless DC motor, the real-time speed, real-time voltage and real-time current of the q-axis and the d-axis in the rotating coordinate system of the brushless DC motor are obtained; Based on the speed error between the given target speed and the real-time speed, a q-axis reference current is calculated by a sliding mode control algorithm; Calculating a d-axis reference current according to a given target power and the real-time voltage; adjusting the torque output of the brushless DC motor according to a current error between the q-axis reference current and the q-axis real-time current; The flux linkage of the brushless DC motor is adjusted according to the current error between the d-axis reference current and the d-axis real-time current.

[0009] In one embodiment, the calculating the q-axis reference current by a sliding mode control algorithm based on the speed error between the real-time speed and the given target speed includes: Defining a sliding mode surface of a sliding mode control system of the brushless DC motor; According to the sliding surface and the system state, a sliding reaching law is designed; Constructing a state space equation of the sliding mode control system according to the mathematical model of the brushless DC motor; Based on the sliding mode surface and the sliding mode reaching law, the q-axis reference current is calculated by the state space equation.

[0010] In one embodiment, according to the sliding surface and the system state, a sliding mode reaching law is designed, including: The sliding mode reaching law is constructed using the hyperbolic tangent function, which is: ; Among them, s is the sliding surface, e represents the error between the actual output and the expected output of the system, is the gain factor.

[0011] In one embodiment, the state space equation of the sliding mode control system is: ; in, , is the target speed, is the real-time speed, for The differential of is the torque coefficient of the brushless DC motor, is the moment of inertia of the brushless DC motor; is the q-axis reference current.

[0012] In one implementation, the calculation formula for the q-axis reference current is: ; in, is the gain factor.

[0013] In a third aspect, an embodiment of the present application provides an intelligent vacuum cleaner, comprising the brushless DC motor control system as described above.

[0014] The brushless DC motor control system, control method and intelligent vacuum cleaner provided in the embodiments of the present application generate a motor control signal through an improved sliding mode control algorithm to control the speed regulation of the brushless DC motor, improve the dynamic stability during the motor speed regulation process, reduce the jitter or overshoot caused by sudden changes in the control input, enable the system to run more smoothly, and enhance the user's operating experience. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the embodiments will be briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present application and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without paying creative work.

[0016] Figure 1 A schematic diagram of the structure of a brushless DC motor control system provided in an embodiment of the present application.

[0017] Figure 2 A schematic flow chart of a brushless DC motor control method provided in an embodiment of the present application.

[0018] Figure 3 A schematic diagram of the brushless DC motor control principle provided in an embodiment of the present application.

[0019] Figure 4 A schematic diagram of the state point switching movement in the sliding surface provided in an embodiment of the present application.

[0020] Figure 5 A schematic diagram of the response of the PI control of the brushless DC motor speed provided in an embodiment of the present application.

[0021] Figure 6 A schematic diagram of the response of the sliding mode control of the brushless DC motor speed provided in an embodiment of the present application. DETAILED DESCRIPTION

[0022] Exemplary embodiments will be described in detail herein, examples of which are shown in the accompanying drawings. When the following description refers to the drawings, the same numbers in different drawings represent the same or similar elements unless otherwise indicated. The implementations described in the following exemplary embodiments do not represent all implementations consistent with the present application. Instead, they are merely examples of devices and methods consistent with some aspects of the present application as detailed in the appended claims.

[0023] It should be noted that, in this article, the terms "include", "comprises" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also includes other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, an element defined by the sentence "includes a ..." does not exclude the existence of other identical elements in the process, method, article or device including the element. In addition, components, features, and elements with the same name in different embodiments of the present application may have the same meaning or different meanings, and their specific meanings need to be determined by their explanation in the specific embodiment or further combined with the context of the specific embodiment.

[0024] It should be understood that, although the terms first, second, third, etc. may be used to describe various information in this article, these information should not be limited to these terms. These terms are only used to distinguish the same type of information from each other. For example, without departing from the scope of this article, the first information may also be referred to as the second information, and similarly, the second information may also be referred to as the first information. Depending on the context, the word "if" as used herein can be interpreted as "at the time of..." or "when..." or "in response to determination". Furthermore, as used in this article, the singular forms "one", "one" and "the" are intended to also include plural forms, unless there is an opposite indication in the context. It should be further understood that the terms "comprising", "including" indicate that there are described features, steps, operations, elements, components, projects, kinds, and / or groups, but do not exclude the existence, occurrence or addition of one or more other features, steps, operations, elements, components, projects, kinds, and / or groups. The terms "or" and "and / or" used herein are interpreted as inclusive, or mean any one or any combination. Thus, “A, B, or C” or “A, B and / or C” means “any of the following: A; B; C; A and B; A and C; B and C; A, B, and C.” An exception to this definition will occur only when a combination of elements, functions, steps, or operations are inherently mutually exclusive in some manner.

[0025] It should be understood that, although the various steps in the flowchart in the embodiment of the present application are displayed in sequence according to the indication of the arrows, these steps are not necessarily performed in sequence according to the order indicated by the arrows. Unless there is a clear explanation in this article, the execution of these steps does not have a strict order restriction, and it can be performed in other orders. Moreover, at least a portion of the steps in the figure may include a plurality of sub-steps or a plurality of stages, and these sub-steps or stages are not necessarily performed at the same time, but can be performed at different times, and their execution order is not necessarily performed in sequence, but can be performed in turn or alternately with other steps or at least a portion of the sub-steps or stages of other steps.

[0026] It should be noted that, in this article, step codes such as S101, S102, etc. are used for the purpose of expressing the corresponding content more clearly and concisely, and do not constitute a substantial limitation on the sequence. When implementing the step, those skilled in the art may execute S102 first and then S101, etc., but these should all be within the scope of protection of this application.

[0027] It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0028] In the subsequent description, the suffixes such as "module", "component" or "unit" used to represent elements are only used to facilitate the description of the present application, and have no specific meanings. Therefore, "module", "component" or "unit" can be used in a mixed manner.

[0029] See also Figure 1 , a brushless DC motor control system provided in an embodiment of the present application, the brushless DC motor control system is applied to an intelligent vacuum cleaner, and the system includes a brushless DC motor, a voltage detection circuit, a current detection circuit, an inverter circuit, a back electromotive force detection circuit, a button detection circuit, a power management circuit and a micro control unit.

[0030] Among them, the voltage detection circuit is used to detect the voltage signal of the brushless DC motor bus. According to the voltage signal, the power of the brushless DC motor during operation can be calculated, and it can also be used as an important basis for judging whether the system is working normally; the current detection circuit is used to detect the current signal of the brushless DC motor bus, and the current signal can be used as a basis for power calculation and realizing the overcurrent protection function; the inverter circuit is used to invert the DC power output by the power module into the three-phase AC power required to drive the brushless DC motor according to the control signal output by the microcontroller unit, so that an alternating magnetic field is generated in the motor winding to drive the motor rotor to rotate; the back electromotive force detection circuit is used to detect the speed and position signals of the brushless DC motor; the key detection circuit is used to determine the gear information of the intelligent vacuum cleaner according to the key input signal, and the system controls the brushless DC motor to switch to different speed modes according to the gear information; the power management circuit is used to convert the output voltage of the power module into the working voltage required by each circuit module; the microcontroller unit is used to generate a motor control signal through a sliding mode control algorithm based on the gear information, voltage signal, current signal, speed and position signal to control the operation of the brushless DC motor.

[0031] In one embodiment, the brushless DC motor control system further includes a voltage and current protection circuit and a temperature protection circuit. The voltage and current protection circuit is used to compare the voltage signal and the current signal with the preset voltage threshold and current threshold, respectively. When the voltage threshold and / or current threshold are exceeded, the microcontroller unit is controlled to output an overvoltage and / or overcurrent protection signal. The temperature protection circuit is used to monitor the temperature of the brushless DC motor when it is working. When the temperature of the brushless DC motor when it is working exceeds the preset temperature threshold, the microcontroller unit is controlled to output an overtemperature protection signal. The voltage and current protection circuit and the temperature protection circuit are used to implement triple protection for the brushless DC motor control system to prevent excessive voltage and current or excessive temperature from causing damage to the equipment.

[0032] In one embodiment, the brushless DC motor control system further includes a voltage stabilizing circuit, which is used to provide a stable power supply voltage so that the brushless DC motor and each circuit module can operate stably under different loads and power supply fluctuations.

[0033] In one embodiment, the brushless DC motor control system also includes a voice module and an information display module, wherein the voice module is used to receive an input voice signal and identify gear information based on the voice signal, that is, by converting the received voice signal into a digital signal and then processing the digital signal, thereby realizing the setting of the power of the intelligent vacuum cleaner and the change of the gear; the information display module is used to display the speed information, voltage information, current information and power information of the brushless DC motor.

[0034] Based on the same inventive concept as the above-mentioned embodiment, the working process of the brushless DC motor control system in the above-mentioned embodiment is described in detail below through a specific example.

[0035] After power is turned on, the brushless DC motor control system first performs hardware initialization and configures the initial state of each peripheral, such as initializing the system clock, GPIO, analog / digital (A / D) conversion module, advanced timer, general timer and other hardware configurations. Then the software is initialized, including assigning initial values ​​to the various parameter variables of the system. In order to ensure the real-time operation of the system, most of the system functions are implemented in interrupts, and the main loop only performs some flag bit detection. The functions implemented in the interrupt include: regularly detecting the voltage of the brushless DC motor through the timer interrupt to ensure that the system works within a safe voltage range; regularly detecting the current flowing through the brushless DC motor through the timer interrupt to realize power calculation; regularly detecting the key input signal through the timer to determine the corresponding gear state, and controlling the speed of the brushless DC motor to switch according to the corresponding gear state; detecting the back electromotive force through the timer to determine the motor speed and the position of the motor rotor, and based on this, current commutation; performing overvoltage and overcurrent interrupts. Once the voltage value or current value exceeds the preset voltage threshold or current threshold, the motor is immediately shut down through the overvoltage protection signal or overcurrent protection signal to prevent the system voltage or current from being too large to damage the circuit.

[0036] In this embodiment, during the operation, the brushless DC motor control system detects the key signal used by the intelligent vacuum cleaner for shifting gears by means of timer polling, and controls the brushless DC motor to perform stepless speed regulation by adjusting the duty cycle of the PWM signal. Specifically, the comparator inside the microcontroller stores the voltage reference value corresponding to the gear position, obtains the working voltage of the motor according to the PWM signal input to the brushless DC motor, compares the working voltage with the voltage reference value in the comparator inside the microcontroller, recalculates the pulse width of the PWM signal according to the comparison result, and autonomously controls the running speed of the motor through an external key signal, realizing the switching of multiple speed modes such as high and low, so as to meet the different requirements of the vacuum cleaner for suction in different application scenarios.

[0037] When the brushless DC motor is running, not all of its energy is converted into mechanical energy, and a considerable portion of it is dissipated into the air in the form of heat. The temperature protection circuit monitors the temperature of the brushless DC motor in real time, and compares the current temperature with the temperature threshold preset in the microcontroller unit. If the current temperature exceeds the temperature threshold, an over-temperature protection signal will be generated, and the microcontroller unit will shut down the operation of the brushless DC motor to ensure the safety of the system, prevent the brushless DC motor from overheating and damage, and extend the service life of the equipment.

[0038] The current detection circuit in this embodiment detects the three-phase current flowing through the brushless DC motor bus through a sampling resistor connected in series on the DC bus, converts the three-phase current signal into a digital signal through an analog-to-digital conversion module and sends it to the microcontroller unit. The microcontroller unit readjusts the PWM signal according to the feedback current signal so that the input current of the motor meets the preset speed and power requirements.

[0039] In this embodiment, the position of the motor is detected by back electromotive force (EMF), and the real-time speed of the motor can be estimated by the rate of change of the back electromotive force. The microcontroller unit can calculate the corresponding control quantity, i.e., the q-axis reference current, according to the target speed corresponding to the gear position and the real-time speed fed back by the system by using the sliding mode control algorithm. Combined with the comparison result of the q-axis reference current with the q-axis real-time current fed back by the system and the d-axis reference current, a corresponding PWM signal is generated by a pulse width modulation generator to control the switching state of each power switching device in the three-phase inverter circuit, so that the motor speed reaches the set value and remains in a stable state, thereby realizing speed control and torque control of the brushless DC motor.

[0040] Combine the following Figure 2 and Figure 3 The brushless DC motor control method based on sliding mode control is introduced in detail. Figure 2 A schematic diagram of a flow chart of a brushless DC motor control method provided in an embodiment of the present application; Figure 3 Schematic diagram of the control principle of a brushless DC motor. The brushless DC motor control method provided in the embodiment of the present application is applied to the brushless DC motor control system described in the above embodiment, such as Figure 2 As shown, the method specifically comprises the following steps: Step S110: acquiring the real-time speed, real-time voltage, and real-time q-axis current and d-axis current of the brushless DC motor in the rotating coordinate system according to the detected speed and position signals, voltage signals, and current signals of the brushless DC motor.

[0041] Specifically, the speed and position signals, voltage signals, and current signals of the brushless DC motor can be obtained by the back electromotive force detection circuit, voltage detection circuit, and current detection circuit in the above embodiments. Figure 3The current loop in is obtained. In the embodiment of the present application, the control of the brushless DC motor adopts a three-closed-loop vector control method, that is, a control method in which the speed loop, the power loop and the current loop are coordinated. The power loop is used as the outer loop of the current loop. The given reference current is calculated according to the power, which can make the control of the motor torque smoother and more suitable for application scenarios that require stable motor operation, fast response speed and high control accuracy. The speed loop in the embodiment of the present application adopts sliding mode control instead of traditional PI control to ensure that the motor speed can reach the set value quickly and accurately. As a nonlinear control strategy, sliding mode control defines a sliding surface in the system state space. When the operating state of the brushless DC motor control system deviates from this surface, the sliding mode speed controller will generate a switching control signal to return the system state to the sliding mode surface, thereby ensuring that the system state can slide along the sliding mode surface, achieving fast response and high-precision control, and also improving the robustness of the system. It can maintain stable operation even when the system parameters change or external interference occurs, and achieve precise control without steady-state errors. As Figure 3 As shown in the figure, when obtaining the real-time current of the q-axis and the d-axis through the current loop, the three-phase current i is first obtained through the three-phase sampling resistor in the current detection circuit. A 、i B 、i C , and then the orthogonal two-phase current i is calculated by Clark transformation α 、i β , and then obtain the current d-axis real-time current i of the motor through Park transformation d and q-axis real-time current i q .

[0042] Step S120: Based on the speed error between the given target speed and the real-time speed, the q-axis reference current is calculated by a sliding mode control algorithm.

[0043] Specifically, the target speed is a preset motor speed corresponding to the gear signal. Step S120 specifically includes: Step S121: defining a sliding mode surface of a sliding mode control system of a brushless DC motor.

[0044] Specifically, sliding mode control is a nonlinear control strategy that controls the system state by changing the control structure. , there exists a sliding surface like Figure 4 As shown in Figure 3, the sliding surface divides the system state space into three parts, including the s>0 part, the s<0 part and the s=0 part.

[0045] In the embodiment of the present application, the sliding surface of the sliding mode control system is defined as: ; Derivative of the sliding surface formula yields: ; in , is the target speed, is the real-time speed, for The differential of is the gain coefficient, and s is the sliding surface.

[0046] Step S122: Design a sliding mode reaching law according to the sliding surface and the system state.

[0047] In general, the sliding mode variable structure usually adopts the exponential reaching law: , the exponential convergence law contains a sign function, which causes the system to be discontinuous when approaching the origin of the coordinate system, resulting in a jitter phenomenon, which may cause the system to overshoot and lose stability. In response to this problem, the present invention improves the exponential convergence law. When the state point is far away from the sliding surface, the exponential term plays a leading role to ensure that the system state can approach the sliding mode at a relatively high speed, which helps to shorten the approach time and make the speed of the moving point when it reaches the sliding surface very small; when approaching the sliding surface, the constant speed convergence law becomes the main control factor. In order to avoid the convergence speed being too fast and exceeding the sliding surface too much, the constant speed convergence law part introduces an error adjustment mechanism to increase the convergence speed when the error increases and reduce the convergence speed when the error decreases, to ensure that the system converges smoothly to the sliding surface. In this application, the hyperbolic tangent function is used instead of the sign function, which improves the jitter phenomenon caused by the discontinuity of the sign function at the origin in the traditional exponential reaching law. The hyperbolic tangent function has the dual functions of smoothing and limiting, which can ensure that the control item generated by the sliding mode control algorithm will not be too large, thereby effectively reducing the amplitude of the output signal and suppressing the jitter phenomenon.

[0048] The sliding mode reaching law is constructed using the hyperbolic tangent function, where The hyperbolic tangent function is: ; The constructed sliding mode reaching law is: ; in, , represents the error between the actual output and the expected output of the system, is the gain coefficient. Selecting an appropriate gain coefficient can further optimize the performance of the control system.

[0049] Step S123: constructing a state space equation of a sliding mode control system according to a mathematical model of the brushless DC motor.

[0050] Specifically, the state space equation of the constructed sliding mode control system is: ; in, is the torque coefficient of the brushless DC motor, is the moment of inertia of the brushless DC motor; is the q-axis reference current .

[0051] Step S124: Based on the sliding mode surface and the sliding mode reaching law, the q-axis reference current is calculated by the state space equation.

[0052] Specifically, the formula for calculating the q-axis reference current is: .

[0053] In the implementation of this application, in order to verify the effectiveness of the improved sliding mode control, a simulation model of traditional PI control and sliding mode control (SMC) was established in Matlab / Simulink software, and a comparative analysis was performed. The simulation time was 0.4s, the motor reference speed was set to 1000r / min, the load torque was 1N•M at the initial moment, and the load torque was 10N•M at 0.2s. The motor speed of PI control is as follows Figure 5 As shown in the figure, the motor speed of the sliding mode control is Figure 6 As shown. According to the simulation results, given a 1000 r / min step signal, the time it takes for the PI control and sliding mode control methods to reach 1000 r / min is almost the same, both 0.05 s. However, the PI control method has a large overshoot. After increasing the load torque for 0.2s, the speed of the PI control mode is affected by the load torque and is below 1000r / min, while the speed under the sliding mode control returns to 1000r / min within 0.05s after the decrease, indicating that the PI mode's ability to resist load disturbances is significantly weaker than that of the sliding mode control. Therefore, it is also verified that the brushless DC motor control system based on sliding mode control in this application has good dynamic stability and anti-disturbance capabilities, and the system has a faster response speed and a smaller degree of error.

[0054] Step S130: Calculate the d-axis reference current according to the given target power and real-time voltage.

[0055] Specifically, the target power is the input power of the motor preset according to the gear position. The corresponding real-time voltage can be calculated based on the PWM signal fed back by the current loop, and the corresponding d-axis reference current can be further calculated based on the preset target power Pr and the real-time voltage. .

[0056] Step S140: adjusting the torque output of the brushless DC motor according to the q-axis current error between the q-axis reference current and the q-axis real-time current.

[0057] Step S150: adjusting the flux linkage of the brushless DC motor according to the d-axis current error between the d-axis reference current and the d-axis real-time current.

[0058] Specifically, since the reference current of the q-axis is directly related to the torque generated by the brushless DC motor, the current of the q-axis is adjusted mainly to control the torque output of the motor, while the reference current of the d-axis is related to the flux linkage of the brushless DC motor. Controlling the current of the d-axis can control the flux linkage of the motor, further affecting the working state of the motor. Real-time current with q axis The current error between the d-axis reference current Real-time current with d-axis The current errors between the two are respectively subjected to PI operation to obtain the corrected q-axis voltage and d-axis voltage , and then the orthogonal two-phase voltage u is obtained through Park inverse transformation α 、u β Finally, the corresponding voltage vector is generated through pulse width modulation, and the final UVW three-phase voltage is generated by the three-phase inverter to drive the brushless DC motor to operate, so that the motor reaches the preset speed and power.

[0059] Based on the same inventive concept as the above embodiments, an embodiment of the present invention further provides an intelligent vacuum cleaner, which includes a brushless DC motor control system as described in the above embodiments.

[0060] To sum up, the brushless DC motor control system, control method and intelligent vacuum cleaner provided in the embodiments of the present application generate a motor control signal through an improved sliding mode control algorithm to control the speed regulation of the brushless DC motor, improve the dynamic stability during the motor speed regulation process, reduce the jitter or overshoot caused by sudden changes in the control input, enable the system to run more smoothly, and enhance the user's operating experience.

[0061] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0062] In this document, the terms "comprises," "comprising," or any other variations thereof, are intended to cover a non-exclusive inclusion of elements other than those listed and may also include additional elements not expressly listed.

[0063] The above is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art can easily think of changes or substitutions within the technical scope disclosed by the present invention, which should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope of the claims.

Claims

1. A brushless DC motor control system, characterized in that: The system includes a brushless DC motor, a voltage detection circuit, a current detection circuit, an inverter circuit, a back electromotive force detection circuit, a key detection circuit, a power management circuit and a micro control unit; wherein, The voltage detection circuit is used to detect the voltage signal of the brushless DC motor bus; The current detection circuit is used to detect the current signal of the brushless DC motor bus; The inverter circuit is used to invert the DC power output by the power module into the three-phase AC power required to drive the brushless DC motor according to the control signal output by the micro control unit; The back electromotive force detection circuit is used to detect the speed and position signals of the brushless DC motor; The key detection circuit is used to determine the preset gear information according to the key input signal; The power management circuit is used to convert the output voltage of the power module into the working voltage required by each circuit module; The micro control unit is used to generate a motor control signal through a sliding mode control algorithm based on the gear information, voltage signal, current signal, speed and position signal to control the operation of the brushless DC motor.

2. The brushless DC motor control system according to claim 1, characterized in that: It also includes a voltage and current protection circuit and a temperature protection circuit; wherein, The voltage and current protection circuit is used to compare the voltage signal and the current signal with a preset voltage threshold and current threshold respectively, and when the voltage threshold and / or current threshold are exceeded, control the micro control unit to output an overvoltage and / or overcurrent protection signal; The temperature protection circuit is used to monitor the temperature of the brushless DC motor during operation, and when the temperature of the brushless DC motor during operation exceeds a preset temperature threshold, the microcontroller unit is controlled to output an over-temperature protection signal.

3. The brushless DC motor control system according to claim 1 or 2, characterized in that: It also includes a voltage stabilizing circuit, which is used to provide a stable power supply voltage so that the brushless DC motor and each circuit module can operate stably under different loads and power supply fluctuations.

4. The brushless DC motor control system according to claim 3, characterized in that: It also includes a voice module and an information display module, wherein: The voice module is used to receive an input voice signal and identify the gear information according to the voice signal; The information display module is used to display the speed information, voltage information, current information and power information of the brushless DC motor.

5. A brushless DC motor control method, characterized in that: The brushless DC motor control system according to any one of claims 1 to 4 is applied, and the method comprises: According to the detected speed and position signals, voltage signals and current signals of the brushless DC motor, the real-time speed, real-time voltage and real-time current of the q-axis and the d-axis in the rotating coordinate system of the brushless DC motor are obtained; Based on the speed error between the given target speed and the real-time speed, a q-axis reference current is calculated by a sliding mode control algorithm; Calculating a d-axis reference current according to a given target power and the real-time voltage; adjusting the torque output of the brushless DC motor according to a current error between the q-axis reference current and the q-axis real-time current; The flux linkage of the brushless DC motor is adjusted according to the current error between the d-axis reference current and the d-axis real-time current.

6. The brushless DC motor control method according to claim 5, characterized in that: The calculating of the q-axis reference current by a sliding mode control algorithm based on the speed error between the real-time speed and the given target speed includes: Defining a sliding mode surface of a sliding mode control system of the brushless DC motor; According to the sliding surface and the system state, a sliding reaching law is designed; Constructing a state space equation of the sliding mode control system according to the mathematical model of the brushless DC motor; Based on the sliding mode surface and the sliding mode reaching law, the q-axis reference current is calculated by the state space equation.

7. The brushless DC motor control method according to claim 6, characterized in that: According to the sliding surface and the system state, a sliding reaching law is designed, including: The sliding mode reaching law is constructed using the hyperbolic tangent function, which is: ； Among them, s is the sliding surface, e represents the error between the actual output and the expected output of the system, is the gain factor.

8. The brushless DC motor control method according to claim 7, characterized in that: The state space equation of the sliding mode control system is: ； in, , is the target speed, is the real-time speed, for The differential of is the torque coefficient of the brushless DC motor, is the moment of inertia of the brushless DC motor; is the q-axis reference current.

9. The brushless DC motor control method according to claim 8, characterized in that: The calculation formula of the q-axis reference current is: ； in, is the gain factor.

10. An intelligent vacuum cleaner, characterized in that: It comprises a brushless DC motor control system as claimed in any one of claims 1 to 4.

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