Motor brake state detection method, system and device and medium

Abstract

The invention relates to the technical field of motor control, in particular to a motor brake state detection method, system and device and a medium, and the method comprises the steps: responding to a brake starting instruction, and starting a brake detection process; judging whether a first condition is met or not, and if yes, starting IQ negative current braking; judging whether a second condition is met or not, if yes, controlling to open a lower bridge switch tube, and enabling the circuit to enter a follow current braking state; and judging whether a third condition is met or not, if yes, generating a BRAKE quit mark, quitting the brake detection process, and controlling the circuit to enter an IDLE state. According to the technical scheme, the circuit structure is simplified, the system hardware cost and complexity are reduced, and the defect that a traditional fixed time waiting method cannot adapt to different loads is overcome; and meanwhile, the quick response capability of the system is improved, and the requirements of industrial automation, electric vehicle driving systems and other scenes for efficient and accurate brake detection are met.

Description

Technical Field

[0001] This application relates to the field of motor control technology, and in particular to a method, system, device and medium for detecting the braking status of a motor. Background Technology

[0002] In the field of motor control technology, accurately determining the stopping state of a motor after braking is a core and critical issue. With the development of motor control systems for industrial automation equipment, electric vehicle drive systems, and other applications requiring rapid start-stop, the industry's demands for rapid response and high efficiency in motor control systems are increasing. Traditional braking status detection methods are no longer sufficient to meet the requirements of modern industry, necessitating a more efficient and accurate braking status detection method.

[0003] In existing technologies, there are two main methods for brake status detection: one is the fixed-time waiting method, which considers the motor to have stopped after waiting for a fixed period of time after braking; the other is the speed detection method, which determines the stopping state by detecting whether the motor speed is zero.

[0004] However, the fixed-time waiting method has a fixed waiting time, which cannot adapt to the actual stopping time of the motor under different load conditions; the speed detection method requires additional sensors, which increases the hardware cost and structural complexity of the system. Summary of the Invention

[0005] In order to solve the problems of existing braking status detection methods, this application provides a method, system, device and medium for detecting motor braking status.

[0006] In a first aspect, this application provides a method for detecting the braking state of a motor, applied to a motor braking state detection circuit. The circuit includes: a controller; a driver; a power supply; a rectifier bridge module, including diodes and capacitors; an inverter bridge module, including an upper bridge switch, a lower bridge switch, a sampling resistor, and a motor; the power supply is connected to the rectifier bridge composed of diodes, and the capacitor is connected in parallel with the rectifier bridge; the inverter bridge module is connected to the rectifier bridge module, the upper bridge switch is connected to the lower bridge switch, each connection node is connected to the motor, and the lower bridge switch is connected to the sampling resistor; the controller is connected to the driver, and the driver is connected to each switch accordingly; the controller is connected to the sampling resistor; the method includes: In response to the brake activation command, initiate the brake detection process; The controller detects the voltage output of the rectifier bridge module and determines whether the first condition is met. If not, it continues to detect the voltage; if so, the controller initiates IQ negative current braking through the driver. The controller detects the speed-related signal and determines whether the second condition is met. If not, it continues to perform IQ negative current braking and detects the speed-related signal. If so, the controller controls the lower bridge switch to be turned on through the driver, so that the circuit enters the freewheeling braking state. The controller detects the current in each phase by sampling resistors to determine whether the third condition is met. If not, it continues to detect the current in each phase; if so, it generates an exit BRAKE flag, exits the brake detection process, and the control circuit enters the idle state.

[0007] By adopting the above technical solution, the output voltage and speed correlation signal of the rectifier bridge module are used as the trigger basis for graded braking. Combined with phase current detection to determine the motor's stopping state, there is no need to configure an additional independent speed sensor. This simplifies the circuit structure, reduces the system hardware cost and complexity, and avoids the shortcomings of the traditional fixed-time waiting method, which cannot adapt to different loads. At the same time, the graded braking through IQ negative current braking and freewheeling braking achieves the synergy of kinetic energy recovery and rapid deceleration. Continuous phase current detection can provide real-time feedback on the motor's operating status, effectively avoiding the overcurrent risk of restarting the motor before it has completely stopped. This significantly shortens the continuous start-stop interval of the motor, improves the system's rapid response capability, and meets the needs of industrial automation, electric vehicle drive systems, and other scenarios for efficient and accurate braking detection.

[0008] In one specific implementation, the first condition includes: the voltage is lower than a preset voltage threshold.

[0009] By adopting the above technical solution, a precise and quantifiable triggering basis is provided for the initiation of IQ negative current braking. This condition can adapt to the circuit voltage fluctuation characteristics, ensuring that IQ negative current braking is only initiated when the bus voltage meets the kinetic energy recovery conditions. This avoids insufficient energy recovery caused by braking too early, and also prevents circuit operation abnormalities caused by starting braking when the voltage is too low. At the same time, it lays the foundation for the smooth connection of subsequent staged braking processes, ensuring the energy utilization efficiency and safety of the braking process.

[0010] In one specific implementation, the second condition includes: the rotational speed corresponding to the rotational speed correlation signal is lower than a preset rotational speed threshold.

[0011] By adopting the above technical solution, precise switching triggering of graded braking is achieved. This condition can match the braking requirements of different speed ranges of the motor, avoiding the instantaneous current impact on core components such as inverter bridge module switching transistors and motors caused by directly switching to freewheeling braking at high speeds, thus extending the service life of power devices. At the same time, it ensures that after IQ negative current braking fully recovers the kinetic energy in the high-speed range, freewheeling braking can smoothly take over the remaining kinetic energy consumption, improving the smoothness and efficiency of the overall braking process and adapting to braking scenarios of motors with different power levels.

[0012] In one specific implementation scheme, the third condition includes: the maximum value of the current in each phase is lower than a preset current threshold for a consecutive preset number of times.

[0013] By adopting the above technical solution, a quantitative judgment standard for the motor's stopping state is established. The design of continuously preset number of times can filter out interference factors such as instantaneous current fluctuations and circuit noise, avoiding misjudgment caused by a single detection point. The limitation of the maximum value of the phase current ensures comprehensive coverage of the operating state of each phase of the motor. This condition can adapt to the motor current decay characteristics under different load conditions, accurately determine whether the motor has truly stopped, avoid the safety risks caused by premature exit from the braking process, and prevent energy waste caused by premature exit, significantly improving the accuracy and reliability of braking detection.

[0014] In one specific implementation, the method of turning on the lower bridge switch includes: the controller sending a continuous conduction signal to the driver to keep each lower bridge switch in a conducting state to achieve freewheeling braking.

[0015] By adopting the above technical solution, the lower bridge switch is kept on by the controller sending a continuous on signal to the driver, which can form a stable and continuous freewheeling circuit. This ensures that the current in the three-phase windings of the motor can flow smoothly through the lower bridge switch and the sampling resistor, and the remaining kinetic energy of the motor can be efficiently consumed through current loss. At the same time, the control method of continuous on signal can avoid voltage fluctuations and device losses caused by frequent switching of the switch, ensuring the stability and consistency of the freewheeling braking process, and helping the motor to decelerate to a stop quickly and smoothly.

[0016] In a specific feasible implementation, the phase current that is not directly acquired through the sampling resistor is derived based on the acquired phase current.

[0017] By adopting the above technical solution, the phase currents that are not directly collected are derived based on the three-phase current balance principle. There is no need to add additional sampling resistors and detection circuits. The complete detection of all phase currents of the motor can be achieved without increasing hardware costs. The derivation process is combined with error correction processing of the collected phase currents to ensure the accuracy of the derivation results. This simplifies the hardware design of the inverter bridge module and ensures the comprehensiveness of phase current detection, providing complete data support for the execution of subsequent current judgment conditions.

[0018] In one specific implementation, the method for exiting the brake detection process includes: the controller sending a shutdown signal to the driver to control the shutdown of each lower bridge switch.

[0019] By adopting the above technical solution, the lower bridge switch is turned off by sending a shutdown signal from the controller. This allows the freewheeling circuit to be disconnected promptly after the motor is confirmed to have stopped, avoiding energy waste and device overheating caused by ineffective freewheeling. At the same time, the circuit quickly returns to an idle state after the lower bridge switch is turned off, enabling a rapid response to the next motor start or brake command, shortening the system response delay, ensuring the high efficiency and stability of the motor control system's cyclic operation, and further improving the overall system operating efficiency.

[0020] Secondly, this application also provides a motor braking state detection system, applied to a motor braking state detection circuit. The circuit includes: a controller; a driver; a power supply; a rectifier bridge module, including diodes and capacitors; an inverter bridge module, including an upper bridge switch, a lower bridge switch, a sampling resistor, and a motor; the power supply is connected to the rectifier bridge composed of diodes, and the capacitor is connected in parallel with the rectifier bridge; the inverter bridge module is connected to the rectifier bridge module, the upper bridge switch is connected to the lower bridge switch, each connection node is connected to the motor, and the lower bridge switch is connected to the sampling resistor; the controller is connected to the driver, and the driver is connected to each switch accordingly; the controller is connected to the sampling resistor; the system includes: The command response module is used to receive the brake start command and trigger the controller to start the brake detection process; The voltage detection module is used to detect the voltage output by the rectifier bridge module through the controller and determine whether the voltage is lower than the preset voltage threshold. The negative current braking module is used to initiate IQ negative current braking by sending a signal to the driver through the controller when the voltage is lower than a preset voltage threshold. The speed detection module is used to detect the speed-related signal through the controller and determine whether the speed corresponding to the speed-related signal is lower than the preset speed threshold. The freewheeling braking module is used to send a signal to the driver through the controller to turn on the lower bridge switch when the speed is lower than the preset speed threshold, so that the circuit enters the freewheeling braking state. The current judgment module is used to detect the current of each phase through the controller and sampling resistor, and cyclically judge whether the current of each phase meets the preset current conditions. The state switching module is used to generate an exit BRAKE flag when the current of each phase meets the preset current conditions, control the exit of the brake detection process and put the circuit into the idle state.

[0021] Thirdly, this application also provides an electronic device, including a processor, a memory, a user interface, and a network interface. The memory is used to store instructions, the user interface and the network interface are used to communicate with other devices, and the processor is used to execute the instructions stored in the memory to enable the electronic device to perform a motor brake state detection method.

[0022] Fourthly, this application also provides a computer-readable storage medium storing multiple instructions adapted for loading and executing a motor brake state detection method by a processor.

[0023] In summary, this application includes at least one of the following beneficial effects: By integrating the voltage, current, and speed-related signal acquisition functions of the controller, there is no need to configure an additional independent speed sensor. The phase current that is not directly acquired is derived by combining the three-phase current balance principle, and there is no need to add additional sampling resistors and detection circuits. This reduces the system hardware cost, simplifies the circuit structure and wiring complexity, and facilitates the miniaturization design of the equipment.

[0024] Abandoning the traditional fixed-time waiting method, a collaborative mechanism of voltage triggering, speed grading, and dual current condition judgment is adopted. By continuously counting and filtering instantaneous current fluctuation interference, the actual stopping state of the motor is accurately identified, effectively avoiding the overcurrent risk of restarting the motor when it has not completely stopped. At the same time, the setting of 70V voltage threshold and 21000r / min speed threshold matches the circuit's safe operating parameters with the optimal braking range, ensuring a smooth and abnormal braking process.

[0025] Kinetic energy recovery is achieved through IQ negative current braking, and freewheeling braking further consumes the remaining kinetic energy. The staged braking design improves the overall deceleration efficiency. Real-time phase current detection replaces fixed waiting, significantly shortening the continuous start-stop interval of the motor and improving the system's rapid response capability. It perfectly meets the core requirements of rapid start-stop in industrial automation, electric vehicle drive systems, and other fields. Attached Figure Description

[0026] Figure 1 This is a flowchart illustrating a method for detecting the braking state of an electric motor according to an embodiment of this application; Figure 2 This is another flowchart illustrating a method for detecting the braking state of a motor provided in an embodiment of this application; Figure 3 This is a schematic diagram of a motor braking state detection circuit provided in an embodiment of this application; Figure 4 This is another schematic diagram of a motor braking state detection circuit provided in an embodiment of this application; Figure 5 This is a detection diagram of phase current waveform and continuous start-stop time interval during motor braking provided in an embodiment of this application; Figure 6 This is a waveform diagram of bus voltage and motor phase current during the kinetic energy recovery process of a motor, provided in an embodiment of this application.

[0027] Figure reference numerals: 10, rectifier bridge module; 11, diode; 20, inverter bridge module; 21, upper bridge switch transistor; 22, lower bridge switch transistor; 23, sampling resistor; 24, motor. Detailed Implementation

[0028] The terminology used in the following embodiments of this application is for the purpose of describing particular embodiments only and is not intended to be limiting of this application. As used in the specification of this application, the singular expressions “a,” “an,” “the,” “the,” and “this” are intended to include the plural expressions as well, unless the context clearly indicates otherwise. It should also be understood that the term “and / or” as used in this application refers to any or all possible combinations including one or more of the listed items.

[0029] Hereinafter, the terms "first" and "second" are used for descriptive purposes only and should not be construed as implying or suggesting relative importance or implicitly indicating the number of indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature, and in the description of the embodiments of this application, unless otherwise stated, "multiple" means two or more.

[0030] The technical solutions in 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.

[0031] refer to Figures 1 to 4 This application provides a method for detecting the braking state of a motor, applied to a motor braking state detection circuit. The circuit includes: a controller; a driver; a power supply; a rectifier bridge module 10, including a diode 11 and a capacitor CE1; an inverter bridge module 20, including an upper bridge switch 21, a lower bridge switch 22, a sampling resistor 23, and a motor 24; the power supply is connected to the rectifier bridge composed of diode 11, and the capacitor CE1 is connected in parallel with the rectifier bridge; the inverter bridge module 20 is connected to the rectifier bridge module 10, the upper bridge switch 21 is connected to the lower bridge switch 22, each connection node is connected to the motor 24, and the lower bridge switch 22 is connected to the sampling resistor 23; the controller is connected to the driver, and the driver is connected to each switch accordingly; the controller is connected to the sampling resistor 23; the method includes: In response to the brake activation command, initiate the brake detection process; The controller detects the voltage output of the rectifier bridge module 10 and determines whether the first condition is met. If not, the controller continues to detect the voltage. If so, the controller initiates IQ negative current braking through the driver. The controller detects the speed-related signal and determines whether the second condition is met. If not, it continues to perform IQ negative current braking and detects the speed-related signal. If so, the controller controls the lower bridge switch 22 to be turned on through the driver, so that the circuit enters the freewheeling braking state. The controller detects the current in each phase through sampling resistor 23 to determine whether the third condition is met. If not, it continues to detect; if so, it generates an exit BRAKE flag, exits the brake detection process, and the control circuit enters the idle state.

[0032] In some embodiments, diode 11 includes diodes D1 to D4. Upper bridge switch 21 includes upper bridge switch Q1, Q3, and Q5, and lower bridge switch 22 includes lower bridge switch Q2, Q4, and Q6. Sampling resistor 23 includes sampling resistors RB1 and RB2. Motor 24 includes three-phase stator windings L1, L2, and L3.

[0033] Specifically, in rectifier bridge module 10, diodes D1, D2, D3, and D4 form a full-bridge rectifier circuit. The live wire of the power supply is connected to the anode of diode D1 and the cathode of diode D3, and the neutral wire of the power supply is connected to the anode of diode D2 and the cathode of diode D4. The cathodes of diodes D1 and D2 are connected together to form the DC positive output terminal of rectifier bridge module 10. The anodes of diodes D3 and D4 are connected together to form the DC negative output terminal of rectifier bridge module 10. One end of capacitor CE1 is connected to the DC positive output terminal of rectifier bridge module 10, and the other end of capacitor CE1 is connected to the DC negative output terminal of rectifier bridge module 10, thereby achieving filtering and voltage regulation of the rectified voltage.

[0034] The DC positive output terminal of the rectifier bridge module 10 is connected to the drain of the upper bridge switching transistors Q1, Q3, and Q5; the source of the upper bridge switching transistor Q1 is connected to the drain of the lower bridge switching transistor Q2, and this connection node is connected to one end of the three-phase stator winding L1; the source of the upper bridge switching transistor Q3 is connected to the drain of the lower bridge switching transistor Q4, and this connection node is connected to one end of the three-phase stator winding L2; the source of the upper bridge switching transistor Q5 is connected to the drain of the lower bridge switching transistor Q6, and this connection node is connected to one end of the three-phase stator winding L3.

[0035] The source of the lower bridge switch Q2 is connected to one end of the sampling resistor RB1, and the source of the lower bridge switch Q4 is connected to one end of the sampling resistor RB2; the source of the lower bridge switch Q6, the other end of the sampling resistor RB1, and the other end of the sampling resistor RB2 are all connected to the DC negative output terminal of the rectifier bridge module 10.

[0036] The controller's PWM signal output terminal is connected one-to-one with the driver's signal input terminal. The driver's drive signal output terminal is connected to the gates of the upper bridge switching transistors Q1, Q3, and Q5, and the gates of the lower bridge switching transistors Q2, Q4, and Q6, respectively, to realize the on / off control of each switching transistor. The controller's current detection terminal is connected to the two ends of the sampling resistor RB1 and the two ends of the sampling resistor RB2, respectively, to collect the voltage drop signal on the sampling resistor, and then obtain the current information of the corresponding lower bridge switching transistor.

[0037] In some embodiments, after receiving a brake start command, the motor control system controller responds to the brake start command and initiates a brake detection process. The controller detects the voltage output by the rectifier bridge module 10 through its connection terminal with the rectifier bridge module 10. The voltage detection unit inside the controller acquires, converts, and analyzes the voltage signal, and then the controller determines whether the detected voltage is lower than a preset voltage threshold.

[0038] If the controller determines that the voltage is not lower than the preset voltage threshold, the controller will continue to detect the voltage output by the rectifier bridge module 10 until the voltage meets the preset condition. If the controller determines that the voltage is lower than the preset voltage threshold, the controller sends an IQ negative current braking start signal to the driver. IQ negative current braking is torque current negative given braking. After receiving the signal, the driver amplifies the signal and outputs it to the corresponding switching transistor to control the start of IQ negative current braking. At this time, the motor enters the generator state and can realize kinetic energy recovery.

[0039] While initiating IQ negative current braking, the controller detects the speed correlation signal, which is an electrical signal that reflects the motor speed. The controller processes and analyzes the speed correlation signal to obtain the corresponding motor speed, and then determines whether the speed is lower than the preset speed threshold.

[0040] If the controller determines that the speed is not lower than the preset speed threshold, the controller will continue to perform IQ negative current braking and continue to detect the speed-related signal until the speed meets the preset conditions. If the controller determines that the speed is lower than the preset speed threshold, the controller sends a signal to the driver to turn on the lower bridge switch 22. After receiving the signal, the driver drives the corresponding lower bridge switch 22 to turn on, so that the circuit enters the freewheeling braking state. Freewheeling can further consume the remaining kinetic energy of the motor and make the motor decelerate quickly.

[0041] After the circuit enters the freewheeling braking state, the controller detects the current of each phase through the connection terminal with the sampling resistor 23. The current detection unit inside the controller filters, amplifies and converts the collected current signal. Then the controller cyclically judges whether the current of each phase meets the preset current conditions.

[0042] If the controller determines that the current in each phase does not meet the preset current condition, the controller will continue to monitor the current in each phase. If the controller determines that the current of each phase meets the preset current conditions, the controller generates an exit BRAKE flag and controls the exit of the brake detection process. Subsequently, the controller sends control signals to the relevant circuit units, and the control circuit enters the idle state, thus completing the entire motor brake status detection program.

[0043] In some embodiments, the rectifier bridge module 10 may have four diodes 11, which together form a full-bridge rectifier circuit; the capacitance of capacitor CE1 may be between 1000 microfarads and 5000 microfarads; the number of upper bridge switches 21 and lower bridge switches 22 may each be three, with the three upper bridge switches 21 and the three lower bridge switches 22 corresponding to the three-phase windings of the motor, respectively; the resistance of sampling resistor 23 may be between 0.01 ohms and 0.1 ohms; and the equivalent inductance of the three-phase stator windings of motor 24 may be between 1 millihenry and 10 millihenry.

[0044] Based on the above embodiments, as another optional embodiment, the first condition includes: the voltage is lower than a preset voltage threshold.

[0045] In some embodiments, the preset voltage threshold is 70V. This preset voltage threshold of 70 volts is determined based on the safe operating parameters of the motor braking state detection circuit and the kinetic energy recovery efficiency, which ensures that the circuit has a good kinetic energy recovery effect when entering IQ negative current braking, while avoiding abnormal circuit operation due to excessively low voltage.

[0046] The controller acquires the voltage signal output by the rectifier bridge module 10 in real time through its connection with the output terminal of the rectifier bridge module 10. The analog-to-digital conversion unit inside the controller converts the acquired analog voltage signal into a digital signal. Then, the controller compares the converted digital voltage signal with a preset 70-volt voltage threshold.

[0047] When the controller determines that the output voltage of the rectifier bridge module 10 is lower than 70 volts, the controller immediately executes the subsequent IQ negative current braking start operation. When the controller determines that the output voltage of the rectifier bridge module 10 is not lower than 70 volts, the controller continues to monitor the voltage until the voltage meets the conditions for starting IQ negative current braking.

[0048] In other embodiments, the preset voltage threshold can be 60V. This value is suitable for low-voltage motor control systems with a rated voltage of 48V. A preset voltage threshold of 60V can accommodate the voltage fluctuation range of the low-voltage system while ensuring safe circuit operation, avoiding braking trigger delay caused by the small voltage reserve of the low-voltage system, and simultaneously ensuring the kinetic energy recovery efficiency and circuit stability during IQ negative current braking startup. In other embodiments, the preset voltage threshold can be 85V. This value is suitable for medium-voltage motor control systems with a rated voltage of 100V. The 85V setting can balance the kinetic energy recovery of the medium-voltage system. The system effectively recovers the kinetic energy of the motor during high-speed operation to charge the capacitor, while also preventing excessive voltage stress on the diodes in the rectifier bridge module or the switching transistors in the inverter bridge module due to excessive voltage, thus extending the service life of the core components. In some embodiments, the preset voltage threshold can also be 55V, which is suitable for small-power micro motors. These motors have relatively small kinetic energy reserves, and a 55V threshold can quickly trigger IQ negative current braking, reducing kinetic energy loss. At the same time, it matches the low-voltage power supply characteristics of the micro motor control system, avoiding the problem of braking failure due to an excessively high threshold.

[0049] Based on the above embodiments, as another optional embodiment, the second condition includes: the rotational speed corresponding to the rotational speed association signal is lower than a preset rotational speed threshold.

[0050] In some embodiments, the preset speed threshold is 21,000 r / min. This preset speed threshold of 21,000 rpm is determined by combining the rated speed of the motor, mechanical strength, and the optimal operating speed range of freewheeling braking. When the motor speed is lower than this threshold, switching to freewheeling braking can effectively reduce the impact on the switching transistors in the inverter bridge module 20 during braking and extend the service life of the switching transistors.

[0051] The controller obtains the real-time motor speed by detecting a speed-related signal, which can be indirectly obtained from the back electromotive force (EMF) signal of the motor's three-phase windings. The controller filters, shapes, and performs frequency analysis on the back EMF signal, and calculates the real-time motor speed based on the correspondence between the frequency of the back EMF and the motor speed. The controller then compares the calculated real-time speed with a preset speed threshold of 21,000 revolutions per minute.

[0052] When the real-time speed is below 21,000 rpm, the controller initiates the freewheeling braking. When the real-time speed is not lower than 21,000 rpm, the controller continues to perform IQ negative current braking and continues to detect the speed-related signal.

[0053] In other embodiments, the preset speed threshold can be 15000 r / min. This value is suitable for medium-speed motors with a rated speed of 18000 r / min. Setting it to 15000 r / min allows the motor to switch to freewheeling braking when the speed drops to the low-to-medium range. At this point, most of the motor's kinetic energy reserve has been consumed through IQ negative current braking, and freewheeling braking can smoothly handle the deceleration process, avoiding the current surge caused by switching to freewheeling braking at higher speeds in medium-speed motors, while also improving the smoothness of the braking process. In other embodiments, the preset speed threshold can be 28000 r / min. This value is suitable for high-speed motors with a rated speed of 30000 r / min. The speed of such motors... With high speed and large kinetic energy, the 28,000 r / min threshold can extend the duration of IQ negative current braking, fully recovering the large amount of kinetic energy during high-speed operation. At the same time, it avoids the instantaneous impact on the motor and switching transistors in the inverter bridge module caused by directly switching to freewheeling braking due to excessive speed, ensuring the safety of the high-speed motor braking process. In some embodiments, the preset speed threshold can also be 10,000 r / min. This value is suitable for low-speed, high-torque motors. These motors have low speed but high torque. The 10,000 r / min setting allows freewheeling braking to intervene earlier, quickly consuming the kinetic energy corresponding to the remaining torque through the loss of the freewheeling circuit, shortening the total braking time, and meeting the braking response speed requirements of heavy equipment.

[0054] Based on the above embodiments, as another optional embodiment, the third condition includes: the maximum value of the current in each phase is lower than the preset current threshold within a preset number of consecutive cycles.

[0055] In some embodiments, the third condition includes: the maximum value of each phase current is less than 0.2A for 25 consecutive times, or the maximum value of each phase current is less than 0.5A for 65 consecutive times. These two third conditions are designed to adapt to the actual needs of motor braking under different load conditions, avoid misjudgments caused by a single current judgment standard, and improve the accuracy and reliability of motor stop state judgment. The controller continuously collects the current signals of each phase through sampling resistor 23. Each time a phase current signal is collected, the controller extracts the maximum value of each phase current signal, compares the extracted maximum value with the corresponding current standard, and counts the number of times the condition is met. For the first case, the controller counts the number of consecutive times the maximum value of each phase current is less than 0.2 amps. When the number of consecutive times reaches 25, the third condition is determined to be met. For the second case, the controller counts the number of consecutive times the maximum value of each phase current is less than 0.5 amps. When the number of consecutive times reaches 65, the third condition is determined to be met. As long as the phase current meets either of the above two conditions, the controller determines that all phase currents meet the third condition and then executes the operation to exit the braking detection process.

[0056] In some embodiments, the third condition can be that the maximum value of the current in each phase is less than 0.1A for 30 consecutive times. This condition is suitable for scenarios with extremely high braking accuracy requirements. The 0.1A current threshold can more accurately determine whether the motor has completely stopped, avoiding equipment displacement or false starts caused by small residual currents. The requirement of 30 consecutive times can filter out high-frequency noise interference that may exist in precision circuits, further improving the reliability of stop judgment. In some embodiments, the third condition can be that the maximum value of the current in each phase is less than 0.3A for 20 consecutive times, or the maximum value of the current in each phase is less than 0.6A for 60 consecutive times. This condition is suitable for motors under heavy load conditions, where there may be small residual loads in the later stages of braking of heavy-load motors. The current thresholds of 0.3A and 0.6A can avoid misjudgments caused by residual load current. The statistical design of 20 and 60 consecutive times can adapt to the slow current decay of heavy-duty motors, ensuring that the stop is determined only after the current stabilizes in the low amplitude range. In some embodiments, the third condition can also be that the maximum value of each phase current is less than 0.15A for 40 consecutive times. This condition is suitable for motors in ordinary industrial automation production lines. The 0.15A threshold balances detection accuracy and anti-interference ability. The statistical requirement of 40 consecutive times can balance judgment speed and reliability. It will not cause misjudgments due to too few statistical times, nor will it prolong the braking exit time due to too many statistical times, adapting to the rhythm requirements of rapid start and stop of production lines.

[0057] In some embodiments, the continuous detection time interval can be 1 millisecond, that is, the controller collects the current signal of each phase every 1 millisecond and performs judgment and statistics to ensure that the changes in phase current can be captured in a timely manner and avoid judgment delay caused by excessively long detection intervals.

[0058] Based on the above embodiments, as another optional embodiment, the method of turning on the lower bridge switch 22 includes: the controller sending a continuous conduction signal to the driver to keep each lower bridge switch 22 in a conducting state to achieve freewheeling braking.

[0059] The continuous conduction signal sent by the controller is a digital level signal with an amplitude of 5 to 12 volts, which meets the input signal requirements of the driver. After receiving the continuous conduction signal from the controller, the driver's internal power amplifier circuit amplifies the signal, ensuring that the output drive signal has sufficient power to drive the lower bridge switch 22 to conduct. After receiving the drive signal output by the driver, the voltage between the gate and source of the lower bridge switch 22 reaches the conduction threshold, and the lower bridge switch 22 enters the conduction state. Until the controller sends a turn-off signal, the driver continuously outputs the drive signal, keeping the lower bridge switch 22 in a stable conduction state. After the lower bridge switch 22 remains on, the current in the three-phase windings of the motor forms a freewheeling circuit through the lower bridge switch 22 and the sampling resistor 23. The losses generated when the current flows in the freewheeling circuit can consume the remaining kinetic energy of the motor, thereby achieving the freewheeling braking function and enabling the motor to decelerate rapidly until it stops.

[0060] Based on the above embodiments, as another optional embodiment, the phase current that is not directly collected through the sampling resistor 23 is derived based on the collected phase current.

[0061] In the motor braking state detection circuit, the sampling resistor 23 of the inverter bridge module 20 typically corresponds to the lower bridge switch 22. For example, only the current signals of phases U and V are collected, while the current signal of phase W is not directly collected through the sampling resistor 23. In this case, the current signal of phase W can be derived based on the three-phase current balance principle. The three-phase current balance principle states that in a three-phase AC circuit, when the circuit is in a symmetrical operating state, the sum of the instantaneous values ​​of the three-phase currents is zero. Assuming that the phase currents directly collected through the sampling resistor 23 are the first and second phase currents, and the phase currents not directly collected are the third phase currents, according to the three-phase current balance principle, the third phase current is equal to the negative value of the algebraic sum of the first and second phase currents.

[0062] The specific derivation logic is as follows: Let the first phase current be I1, the second phase current be I2, and the third phase current be I3. Then, according to the three-phase current balance principle, I1+I2+I3=0. From this, we can deduce that I3=-(I1+I2).

[0063] In the derivation process, the controller first performs error correction processing on the acquired first and second phase current signals to eliminate errors caused by noise, interference, and other factors during signal acquisition. Then, the corrected first and second phase currents are substituted into the above derivation formula to calculate the value of the third phase current. This derivation method eliminates the need for an additional sampling resistor 23 to acquire all phase current signals, simplifying the circuit structure, reducing costs, and ensuring the integrity and accuracy of phase current detection.

[0064] Based on the above embodiments, as another optional embodiment, the method for exiting the brake detection process includes: the controller sending a shutdown signal to the driver to control each lower bridge switch 22 to shut down.

[0065] Once the controller determines that all phase currents meet the preset current conditions, it generates a braking exit flag and simultaneously sends a shutdown signal to the driver. This shutdown signal is a low-level signal with an amplitude of 0 volts. Upon receiving the shutdown signal from the controller, the driver's internal power amplifier circuit stops outputting drive signals, and the voltage between the gate and source of the lower bridge switch 22 drops below the cutoff threshold, switching the lower bridge switch 22 from the on state to the off state. After each lower bridge switch 22 is turned off, the freewheeling braking circuit is disconnected, and the freewheeling current in the motor's three-phase windings gradually decays to zero, thus the motor is no longer subjected to braking torque. After controlling the lower bridge switch 22 to turn off, the controller also resets other related units in the circuit, such as resetting the current detection statistics count and clearing the braking status flag, restoring the entire circuit to its initial idle state. This prepares the circuit for the next motor start or braking operation, ensuring stable and reliable cyclic operation.

[0066] refer to Figure 5 This application provides a detection diagram of phase current waveform and continuous start-stop time interval during motor braking. In the diagram, the phase current waveform remains in a low amplitude range during the later stages of braking, perfectly matching the stop judgment condition in this solution where the maximum phase current continuously meets a preset threshold. This proves that this solution can accurately identify the actual stopping state of the motor through phase current detection, avoiding the risk of misjudgment. Simultaneously, the diagram shows that the continuous start-stop time interval is only 155ms, significantly shorter than the over 250ms interval of the traditional fixed-time waiting method. This verifies that this solution can significantly improve the rapid response capability of the motor control system, adapting to the rapid start-stop requirements of scenarios such as industrial automation and electric vehicle drives.

[0067] refer to Figure 6 This application provides a waveform diagram of bus voltage and motor phase current during motor kinetic energy recovery. In the diagram, the blue waveform corresponds to the bus voltage, and the yellow waveform corresponds to the motor phase current. The waveform changes show that after IQ negative current braking is initiated, the motor phase current exhibits fluctuation characteristics matching the braking logic. Simultaneously, the bus voltage remains stable without abnormal drops as the phase current changes. This indicates that the IQ negative current braking scheme of this method can effectively convert motor kinetic energy into electrical energy of the bus capacitor, achieving efficient kinetic energy recovery, avoiding the ineffective loss of kinetic energy in traditional braking methods, and improving the system's energy utilization efficiency.

[0068] In summary, we can conclude that the voltage-triggered graded braking and precise phase current judgment mechanism of this scheme not only achieves efficient kinetic energy recovery but also ensures the accuracy of braking status detection and the rapid response of the system; whileFigure 5 , Figure 6 The waveform data directly corroborates the technical advantages of this solution in terms of energy utilization efficiency, detection reliability, and response speed, further supporting the practicality and advancement of this solution compared to traditional technologies.

[0069] This application embodiment also provides a motor brake state detection system, characterized in that it is applied to a motor brake state detection circuit, the circuit including: a controller; a driver; a power supply; a rectifier bridge module 10, including a diode 11 and a capacitor CE1; an inverter bridge module 20, including an upper bridge switch 21, a lower bridge switch 22, a sampling resistor 23, and a motor 24; the power supply is connected to the rectifier bridge composed of diode 11, and the capacitor CE1 is connected in parallel with the rectifier bridge; the inverter bridge module 20 is connected to the rectifier bridge module 10, the upper bridge switch 21 is connected to the lower bridge switch 22, each connection node is connected to the motor 24, and the lower bridge switch 22 is connected to the sampling resistor 23; the controller is connected to the driver, and the driver is connected to each switch accordingly; the controller is connected to the sampling resistor 23; the system includes: The command response module is used to receive the brake start command and trigger the controller to start the brake detection process; The voltage detection module is used to detect the voltage output by the rectifier bridge module 10 through the controller and determine whether the voltage is lower than the preset voltage threshold. The negative current braking module is used to initiate IQ negative current braking by sending a signal to the driver through the controller when the voltage is lower than a preset voltage threshold. The speed detection module is used to detect the speed-related signal through the controller and determine whether the speed corresponding to the speed-related signal is lower than the preset speed threshold. The freewheeling braking module is used to send a signal to the driver through the controller to turn on the lower bridge switch 22 when the speed is lower than the preset speed threshold, so that the circuit enters the freewheeling braking state. The current judgment module is used to detect the current of each phase through the controller and sampling resistor 23, and cyclically judge whether the current of each phase meets the preset current conditions. The state switching module is used to generate an exit BRAKE flag when the current of each phase meets the preset current conditions, control the exit of the brake detection process and put the circuit into the idle state.

[0070] Based on the above embodiments, as another optional embodiment, this application embodiment may further include a computer storage medium, which may store multiple instructions. The instructions are adapted to be loaded by a processor and executed by a motor brake state detection method of the above embodiments. For the specific execution process, please refer to the detailed description of the above embodiments, which will not be repeated here.

[0071] Based on the above embodiments, as another optional embodiment, this application embodiment may further include an electronic device. The electronic device may include: at least one processor, at least one communication bus, a user interface, at least one network interface, and a memory.

[0072] The communication bus is used to enable communication between these components.

[0073] The user interface may include a display screen and a camera. Optional user interfaces may also include standard wired interfaces and wireless interfaces.

[0074] The network interface may include standard wired interfaces and wireless interfaces (such as Wi-Fi interfaces).

[0075] The processor may include one or more processing cores. It connects to various parts of the server via various interfaces and lines, executing instructions, programs, code sets, or instruction sets stored in memory, and accessing data stored in memory to perform various server functions and process data. Optionally, the processor may be implemented using at least one of the following hardware forms: Digital Signal Processing (DSP), Field-Programmable Gate Array (FPGA), and Programmable Logic Array (PLA). The processor may integrate one or more of the following: Central Processing Unit (CPU), Graphics Processing Unit (GPU), and modem. The CPU primarily handles the operating system, user interface, and applications; the GPU is responsible for rendering and drawing the content displayed on the screen; and the modem handles wireless communication. It is understood that the modem may also be implemented as a separate chip without being integrated into the processor.

[0076] The memory may include random access memory (RAM) or read-only memory. Optionally, the memory may include a non-transitory computer-readable storage medium. The memory can be used to store instructions, programs, code, code sets, or instruction sets. The memory may include a program storage area and a data storage area, wherein the program storage area may store instructions for implementing an operating system, instructions for at least one function (such as touch function, sound playback function, image playback function, etc.), instructions for implementing the above-described method embodiments, etc.; the data storage area may store data involved in the above-described method embodiments, etc. Optionally, the memory may also be at least one storage device located remotely from the aforementioned processor. As a computer storage medium, the memory may include an operating system, a network communication module, a user interface module, and an application program for a motor brake state detection method.

[0077] In electronic devices, the user interface is primarily used to provide an input interface for users and to acquire user input data. The processor can be used to call an application program stored in memory for detecting a motor brake state. When executed by one or more processors, this causes the electronic device to perform one or more methods as described in the above embodiments. It should be noted that, for the foregoing method embodiments, for the sake of simplicity, they are all described as a series of actions. However, those skilled in the art should understand that this application is not limited to the described order of actions, because according to this application, some steps can be performed in other orders or simultaneously. Furthermore, those skilled in the art should also understand that the embodiments described in the specification are preferred embodiments, and the actions and modules involved are not necessarily essential to this application.

[0078] In the above embodiments, the descriptions of each embodiment have different focuses. For parts not described in detail in a certain embodiment, please refer to the relevant descriptions in other embodiments.

[0079] In the various embodiments provided in this application, it should be understood that the disclosed apparatus can be implemented in other ways. For example, the apparatus embodiments described above are merely illustrative; for instance, the division of units is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the coupling or direct coupling or communication connection shown or discussed may be through some service interface; the indirect coupling or communication connection between apparatuses or units may be electrical or other forms.

[0080] The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.

[0081] Furthermore, the functional units in the various embodiments of this application can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit. The integrated unit can be implemented in hardware or as a software functional unit.

[0082] If the integrated unit is implemented as a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage device (CMD). 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 memory and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods of the various embodiments of this application. The aforementioned memory includes various media capable of storing program code, such as USB flash drives, portable hard drives, magnetic disks, or optical disks.

[0083] The above are merely exemplary embodiments of this disclosure and should not be construed as limiting the scope of this disclosure. Any equivalent changes and modifications made in accordance with the teachings of this disclosure shall still fall within the scope of this disclosure. Other embodiments of this disclosure will readily conceive of those skilled in the art upon consideration of the specification and the disclosure of practical truths.

[0084] This application is intended to cover any variations, uses, or adaptations of this disclosure that follow the general principles of this disclosure and include common knowledge or customary techniques in the art not described in this disclosure. The specification and embodiments are to be considered exemplary only, and the scope and spirit of this disclosure are defined by the claims.

Claims

1. A method for detecting the braking state of an electric motor, characterized in that, An application is provided in a motor braking state detection circuit. The circuit includes: a controller; a driver; a power supply; a rectifier bridge module, including diodes and capacitors; an inverter bridge module, including an upper bridge switch, a lower bridge switch, a sampling resistor, and a motor; the power supply is connected to the rectifier bridge composed of diodes, and the capacitor is connected in parallel with the rectifier bridge; the inverter bridge module is connected to the rectifier bridge module, the upper bridge switch is connected to the lower bridge switch, each connection node is connected to the motor, and the lower bridge switch is connected to the sampling resistor; the controller is connected to the driver, and the driver is connected to each switch accordingly; the controller is connected to the sampling resistor; the method includes: In response to the brake activation command, initiate the brake detection process; The controller detects the voltage output by the rectifier bridge module and determines whether the first condition is met. If not, it continues to detect the voltage. If so, the controller initiates IQ negative current braking through the driver. The controller detects the speed-related signal and determines whether the second condition is met. If not, it continues to perform IQ negative current braking and detects the speed-related signal. If yes, the controller controls the lower bridge switch to be turned on through the driver, so that the circuit enters the freewheeling braking state. The controller detects the current of each phase through the sampling resistor to determine whether the third condition is met. If not, it continues to detect the current of each phase; if so, it generates an exit BRAKE flag, exits the brake detection process, and controls the circuit to enter the idle state.

2. The method for detecting the braking state of a motor according to claim 1, characterized in that, The first condition includes: the voltage is lower than a preset voltage threshold.

3. The method for detecting the braking state of a motor according to claim 2, characterized in that, The second condition includes: the rotational speed corresponding to the rotational speed correlation signal is lower than a preset rotational speed threshold.

4. The method for detecting the braking state of a motor according to claim 3, characterized in that, The third condition includes: the maximum value of each phase current is lower than a preset current threshold for a consecutive preset number of times.

5. The method for detecting the braking state of a motor according to claim 4, characterized in that, The method of turning on the lower bridge switch includes: the controller sending a continuous conduction signal to the driver to keep each of the lower bridge switch in a conducting state to achieve freewheeling braking.

6. The method for detecting the braking state of a motor according to claim 5, characterized in that, Based on the acquired phase current, the phase current that was not directly acquired through the sampling resistor is derived.

7. The method for detecting the braking state of a motor according to claim 6, characterized in that, The method for exiting the brake detection process includes: the controller sending a shutdown signal to the driver to control each of the lower bridge switches to turn off.

8. A motor braking status detection system, characterized in that, An application is provided in a motor braking state detection circuit. The circuit includes: a controller; a driver; a power supply; a rectifier bridge module, including diodes and capacitors; an inverter bridge module, including an upper bridge switch, a lower bridge switch, a sampling resistor, and a motor; the power supply is connected to the rectifier bridge composed of diodes, and the capacitor is connected in parallel with the rectifier bridge; the inverter bridge module is connected to the rectifier bridge module, the upper bridge switch is connected to the lower bridge switch, each connection node is connected to the motor, and the lower bridge switch is connected to the sampling resistor; the controller is connected to the driver, and the driver is connected to each switch accordingly; the controller is connected to the sampling resistor; the system includes: The command response module is used to receive the brake start command and trigger the controller to start the brake detection process. A voltage detection module is used to detect the voltage output by the rectifier bridge module through the controller and determine whether the voltage is lower than a preset voltage threshold. A negative current braking module is used to send a signal to the driver through the controller to initiate IQ negative current braking when the voltage is lower than the preset voltage threshold. The speed detection module is used to detect the speed-related signal through the controller and determine whether the speed corresponding to the speed-related signal is lower than a preset speed threshold. The freewheeling braking module is used to send a signal to the driver through the controller to turn on the lower bridge switch when the rotational speed is lower than the preset rotational speed threshold, so that the circuit enters the freewheeling braking state. The current judgment module is used to detect the current of each phase through the controller and the sampling resistor, and cyclically judge whether the current of each phase meets the preset current conditions. The state switching module is used to generate an exit BRAKE flag when the current of each phase meets the preset current condition, control the exit of the brake detection process and put the circuit into the idle state.

9. An electronic device, characterized in that, It includes a processor, a memory, a user interface, and a network interface. The memory is used to store instructions, the user interface and the network interface are used to communicate with other devices, and the processor is used to execute the instructions stored in the memory to cause the electronic device to perform the method as described in any one of claims 1-7.

10. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores multiple instructions suitable for being loaded by a processor and executed as described in any one of claims 1-7.

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