A motor and pump combination control method for preventing hydraulic pump reverse rotation

Abstract

The application discloses a motor and pump combination control method for preventing hydraulic pump reverse rotation, and belongs to the technical field of hydraulic pump control, and comprises the following steps: a motor controller monitors the motor operation state in real time; when it is monitored that the motor fails, anti-reverse rotation control of the motor side is performed, and a failure signal is sent to the controller of the pump; the anti-reverse rotation control of the motor side is that the motor controller first controls the motor to cut into the FW mode; when the bus capacitor voltage reaches a preset threshold or the charging duration reaches a set value, the motor is controlled to switch to the ASC mode; then the ASC mode is continuously maintained; after receiving the failure signal, the controller of the pump immediately controls the hydraulic pump to perform a flow cut-off operation, cuts off the pressure supply source of the hydraulic pump, and cooperates with the electromagnetic braking torque of the motor side to realize hydraulic pump reverse rotation prevention. The application fundamentally eliminates the conditions leading to pump reverse rotation, so that the pump has no opportunity to start reverse rotation, thereby protecting the damage of the pump structure caused by pump reverse rotation, and active prevention is realized.

Description

Technical Field

[0001] This invention relates to the field of hydraulic pump control technology, specifically to a method for controlling the combination of a motor and a pump to prevent the hydraulic pump from reversing. Background Technology

[0002] When a pump is operating at high speed, if the motor suddenly experiences overvoltage, undervoltage, overcurrent, or other motor or system malfunctions, the motor will enter a fault mode, stop working, and shut down. Because the pump itself still rotates, it will reverse due to the residual pressure at the pump output. This reverse pump rotation can damage the pump's structure, and it is necessary to prevent it from happening.

[0003] Traditional methods for preventing pump reversal (such as mechanical check valves) are "passive defenses," meaning mechanical blocking occurs after or during reversal. For example, patent document CN204386989U discloses an anti-shock and anti-reversal hydraulic system for a one-way hydraulic motor, including a hydraulic pump providing power to the system, a relief valve providing safety protection, a two-position four-way solenoid directional valve, a one-way hydraulic motor, and a check valve. Specifically, one input port of the two-position four-way solenoid directional valve is connected to the hydraulic pump, and the other input port is connected to the oil tank. The two output ports of the two-position four-way solenoid directional valve are respectively connected to the oil inlet and return ports of the one-way hydraulic motor. The relief valve is connected to the hydraulic pump, and the check valve is connected to the one-way hydraulic motor. By adopting the above technical solution, this solution utilizes the check valve circuit to avoid hydraulic shock to the hydraulic motor caused by the closing of the solenoid directional valve and can prevent the hydraulic motor from rotating in reverse. However, it only blocks the reverse oil path by the mechanical structure of the check valve when the reversal trend occurs, and cannot intervene in advance; it relies on the reliability of the check valve and has no active intervention mechanism, so it is only suitable for one-way hydraulic motors.

[0004] Existing technologies also include methods to prevent pump reversal through hydraulic system control. For example, patent document CN110805581B discloses a novel hydraulic reverse-drive control system, comprising: a reverse-drive control device, one end of which is connected to the first and second oil outlets of the hydraulic pump via hydraulic pipes, and the other end of which is connected to the forward and reverse oil inlets of the first and second hydraulic motors via hydraulic pipes; and a reverse-drive controller, electrically connected to the reverse-drive control device, used to control the opening and closing of valves within the reverse-drive control device, protecting the hydraulic system of the hydraulically driven vehicle and preventing excessive pressure in the hydraulic system and engine reverse drag. However, this only addresses hydraulic system pressure feedback adjustment and does not involve active braking torque control at the motor end, thus failing to eliminate the root cause of reverse rotation.

[0005] In traditional technology systems, motor control and hydraulic control have long been isolated: the motor side focuses on energy dissipation and device protection during faults, while the hydraulic side relies on mechanical check valves or hydraulic valve assemblies for passive blocking. Technicians typically stick to a single domain, neither using the electromagnetic braking torque of ASC (Active Short Circuit) mode to lock the motor and pump shaft, nor designing logic to continuously maintain the ASC state to counteract residual pressure reversal torque.

[0006] Currently, ASC (Automatic Reverse Flow Control) is only understood as an energy release mechanism in the early stages of a fault. Once the back EMF falls below the bus voltage, it switches back to FW (Failure-Warping) mode to prevent winding overheating. This fixed mindset leads to the neglect of its shaft-locking potential. Furthermore, hydraulic anti-reverse mechanisms have long followed a passive approach of addressing the problem only after it occurs, making it difficult to shift towards proactive prevention that eliminates the conditions for reversal at their root.

[0007] Even with attempts at cross-domain collaboration, significant technical challenges remain: First, synchronizing the timing of the motor-side electronic control response (microseconds / milliseconds) and the hydraulic-side mechanical response (milliseconds) is difficult, requiring zero-delay transmission of the CAN bus and precise linkage between both ends; Second, there is a contradiction in the thermal risk caused by the continuous maintenance of ASC. Conventional logic would exit ASC after the back EMF drops to prevent overheating, but this invention needs to maintain ASC for a very short time (e.g., 0.02s) to complete the locking, requiring a precise balance between braking torque demand and winding thermal protection.

[0008] In summary, none of the existing technologies utilize the electronic control system to monitor faults in real time and proactively eliminate the fundamental conditions that cause reverse rotation. When the motor stops due to faults such as overvoltage, undervoltage, or overcurrent, the pump body continues to rotate due to inertia, and the residual pressure on the output side will drive the pump to reverse. However, existing technologies cannot generate braking torque at the motor end to lock the motor and pump shaft, nor can they quickly cut off the pump's flow output to reduce residual pressure, making it difficult to fundamentally avoid the risk of reverse rotation. Summary of the Invention

[0009] This invention addresses the problem of overly simplistic solutions in existing technologies by providing a significantly different approach. It primarily offers a motor-pump combination control method to prevent hydraulic pump reversal. This method intervenes before reversal occurs by generating braking torque at the motor end to lock the motor and pump shaft, and quickly cuts off the pump's flow output to reduce residual pressure, fundamentally avoiding the risk of reversal.

[0010] The technical solution adopted by the present invention to solve the above-mentioned technical problems is as follows: A method for controlling the motor and pump to prevent reverse rotation of a hydraulic pump includes: The motor controller monitors the motor's operating status in real time; when a motor fault is detected, it performs anti-reverse control on the motor side and sends a fault signal to the pump's controller. The anti-reverse control on the motor side is as follows: The motor controller first controls the motor to switch to FW mode, using the motor back EMF to charge the bus capacitor; then, when the bus capacitor voltage reaches a preset threshold or the charging time reaches a set value (millisecond level), the controller controls the motor to switch to ASC mode, so that the motor stator winding forms a closed loop to generate electromagnetic braking torque; then, when the motor back EMF drops below the bus voltage, the controller controls the motor to continue to maintain ASC mode, locking the motor shaft through electromagnetic braking torque; After receiving the fault signal, the pump controller immediately controls the hydraulic pump to perform a flow cut-off operation, cutting off the pressure supply source of the hydraulic pump, and cooperating with the electromagnetic braking torque on the motor side to prevent the hydraulic pump from reversing.

[0011] Furthermore, the motor controller monitors the motor speed and estimates the torque in real time. When the motor is in a non-braking command state and the speed deceleration rate exceeds 500 rpm / s, or the speed approaches 0 rpm, if an unexpected reverse load torque is detected, it is determined that the motor has failed and the subsequent fault response process is triggered in advance.

[0012] Furthermore, the FW mode is a freewheeling mode in which all three-phase rectifier circuits of the motor are disconnected, and the back electromotive force of the motor is fed back to the bus capacitor and the power battery through the inverter anti-parallel diode.

[0013] Furthermore, the ASC mode is implemented by controlling all three upper or lower bridge arms of the inverter to be turned on, while keeping the opposite three bridge arms off.

[0014] Furthermore, the fault signal is a high-priority fault instruction, and its transmission method includes: assigning a low-value identifier to the CAN message carrying the fault information to obtain bus arbitration priority, and adopting an event triggering mechanism to immediately interrupt the transmission of regular messages and forcibly insert a fault message when a fault occurs.

[0015] Furthermore, the flow cut-off operation is as follows: the pump controller sends a control current to the solenoid valve of the hydraulic pump, driving the variable mechanism of the hydraulic pump to reduce the theoretical displacement of the pump to zero.

[0016] Furthermore, the solenoid valve has a response time ≤15ms, a flow ramp descent gradient ≥1000L / min / s, and a total execution time from the issuance of the fault signal to the return of the flow to zero ≤50ms.

[0017] Furthermore, the hydraulic pump is an electronically controlled variable displacement piston pump; after receiving the fault signal, the pump controller immediately cuts off or adjusts the drive current output to the proportional solenoid valve of the piston pump; under the action of the control current change, the servo mechanism inside the piston pump drives the swashplate to move rapidly; the swashplate tilt angle is reset to zero degrees from the current working angle within milliseconds.

[0018] Furthermore, the time taken for the motor speed to drop from the operating speed to a steady state is ≤20 milliseconds.

[0019] Furthermore, it also includes a vehicle controller, which is used to monitor the operating status of the motor controller and the pump controller, and to disconnect the main relay to achieve secondary protection in case of abnormality.

[0020] This invention monitors the status of the motor controller and pump controller through the vehicle controller and cuts off the main relay when there is an abnormality. It builds a redundant protection mechanism on the basis of motor-pump collaborative protection and achieves backup protection by cutting off the high voltage power supply of core components. This avoids the problem that the pump still has the risk of reversal after the failure of the first-level collaborative protection under extreme working conditions, and further improves the stability and safety of the entire hydraulic pump anti-reversal system.

[0021] Compared with the prior art, the beneficial effects of the present invention are as follows: (1) After a fault is detected, the motor controller of the present invention controls the motor to first switch to FW mode to charge the bus capacitor, and then switches to ASC mode and maintains it continuously. First, the anti-parallel diode feedback charging effect of FW mode is used to realize instantaneous high energy discharge of the motor winding to avoid burnout of power devices. Then, the stator winding of the motor is short-circuited through ASC mode to form electromagnetic braking torque. After the back EMF is lower than the bus voltage, the ASC state is maintained to generate dynamic damping torque to lock the motor shaft. Since the residual pressure can be quickly cut off on the pump side, ASC only needs to lock for a very short time to complete the protection. Compared with the prior art, the present invention overcomes the technical bias that ASC mode is only used for motor device protection, and that it needs to switch back to FW mode after the back EMF is reduced, as well as the technical difficulty of balancing the thermal risk of ASC being maintained continuously. It solves the technical problem that the traditional technology cannot eliminate the pump reversal power from the source through the motor active braking torque, and realizes the rapid locking of the motor shaft to prevent the pump from reversing due to motor inertia.

[0022] (2) After receiving a high-priority fault command, the pump controller of the present invention drives the variable mechanism to reduce the theoretical displacement of the pump to zero. With the help of the rapid response of the solenoid valve and the mechanical action of the servo mechanism, the flow output of the hydraulic pump is cut off from the pressure source, which greatly reduces the residual pressure on the pump output side. Moreover, the total flow zeroing time of ≤50ms is used to achieve synchronization with the motor ASC lock-up. Compared with the prior art, the present invention overcomes the technical bias of hydraulic anti-reverse relying solely on the mechanical blockage of the oil circuit, which cannot achieve a step-like zeroing of the flow, as well as the technical difficulty of the mismatch between the hydraulic side response and the motor electronic control response timing. It solves the technical problem that traditional hydraulic control methods cannot quickly eliminate the residual pressure cause of pump reversal, and completely eliminates the hydraulic power basis for pump reversal with the braking torque on the motor side.

[0023] (3) This invention achieves synchronous triggering of motor-side mode switching and pump-side flow cutoff through a collaborative architecture combining high-priority fault messages on the CAN bus with MCU main control and pump controller execution, ensuring zero-delay transmission of fault signals and precise linkage of actions at both ends. Compared with the prior art, this invention overcomes the technical bias of the separation between motor and hydraulic control fields, the lack of collaborative control logic, and the technical difficulty of cross-system control timing synchronization; it solves the technical problem of independent control of motor and pump in the prior art, which cannot form a combined force to prevent reverse rotation, and realizes the upgrade from single-device protection to system-level active prevention, improving the response speed and reliability of anti-reverse rotation control.

[0024] (4) This invention utilizes the technical characteristics of monitoring the motor speed reduction rate (>500 rpm / s) and the reverse load torque when the speed approaches 0 rpm. By leveraging the microsecond-level calculation cycle of the electronic control system, it identifies the risk of reversal and triggers protection in advance before the motor speed crosses zero (before substantial reversal occurs). Compared with existing technologies, this invention overcomes the technical bias of passively intervening only when reversal occurs or after it occurs to prevent reversal; it solves the technical problem that traditional technologies can only block reversal after the fact and cannot eliminate the risk in advance. This invention achieves advance identification and prevention of reversal risk and avoids impact damage to the pump structure in the early stage of reversal.

[0025] In summary, this invention, through its end-to-end technical features of active motor locking, pump flow interruption, and early risk prediction, and leveraging the mechanism of coordinated electronic control intervention and elimination of reversal conditions at the source, achieves proactive prevention of reversal before it occurs. Compared to existing technologies, it overcomes the conventional approach of passively enduring and not actively managing reversal prevention; it solves the technical problems of delayed response, easy damage to pump structure, and poor system dynamic response in existing anti-reversal technologies. It not only protects the hydraulic pump from damage caused by reversal but also reduces hydraulic shock, improving the stability and service life of the entire equipment.

[0026] The present invention will be explained in detail below with reference to the accompanying drawings and specific embodiments. Attached Figure Description

[0027] Figure 1 A control block diagram of the method provided for this invention; Figure 2 This is a graph showing the test results of the control group in the experiment of this invention; Figure 3 This is a graph showing the test results of the experimental group in the experiment of this invention. Detailed Implementation

[0028] To facilitate understanding of the present invention, a more comprehensive description of the present invention will be given below with reference to the accompanying drawings, which illustrate several embodiments of the present invention. However, the present invention can be implemented in different forms and is not limited to the embodiments described in the text. Rather, these embodiments are provided to make the disclosure of the present invention more thorough and complete.

[0029] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly associated with those skilled in the art to which this invention pertains. The terminology used herein in the specification of this invention is for the purpose of describing particular embodiments and is not intended to limit the invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0030] Example: Please refer to the appendix for details. Figure 1 A method for controlling the motor and pump to prevent hydraulic pump reversal includes: I. Fault Triggering: Add logical judgment to assess risks by monitoring motor torque and speed. When motor torque and speed become abnormal (torque suddenly rises to the set value, speed suddenly drops to 0 rpm), the motor can no longer work normally, but the pump is still working. At this time, the motor controller needs to control the motor and hydraulic sides simultaneously to identify the risk before physical reversal occurs.

[0031] Risks can be identified early by monitoring abnormal mismatches in the rate of change of rotational speed (acceleration) and torque direction. Specifically: The MCU monitors motor speed and estimates torque in real time. When the motor is in a non-braking state—that is, when it should be driving or coasting—a sharp drop in speed is detected (i.e., a deceleration rate much greater than that of natural coasting) exceeding a set threshold (e.g., deceleration rate > 500 rpm / s); or when the motor speed is about to cross zero, a large reverse load torque is detected at the motor shaft end (an unexpected load component is analyzed through current). These situations indicate that the residual pressure in the hydraulic system is generating a large reverse thrust, attempting to overcome the motor's inertia.

[0032] Fault information is added to the fastest-transmitting frame of the CAN message. When the motor or system experiences a fault such as overvoltage, undervoltage, or overcurrent, a frame of data in the CAN message will be set from 0 to 1, thus indicating a motor fault. The motor controller (MCU) then sends a fault signal to the pump controller.

[0033] High-priority frame ID allocation: In CAN bus communication protocols (such as CAN 2.0B or CAN FD), messages containing motor fault information are assigned extremely low identifier (ID) values ​​(e.g., 0x0C0 or lower). According to the CAN bus arbitration mechanism, the smaller the ID value, the higher the priority, enabling it to preempt bus control and ensuring that fault signals are not blocked by other messages (such as instrument displays or general status information), achieving zero-delay transmission.

[0034] Fault triggering mechanism: Once the MCU determines that a fault has occurred, it immediately interrupts the current transmission task and forcibly inserts a fault message frame. This means that the communication delay for fault response is only limited by the time of the data frame currently being transmitted on the bus, achieving microsecond-level communication response.

[0035] II. Motor-side control 1. FW (Energy Release Phase) When the MCU detects an overvoltage, undervoltage, or overcurrent fault in the motor, it immediately blocks the IGBT drive signal, putting the motor in a three-phase disconnected state. Due to the high-speed rotation of the motor, a back electromotive force (EMF) exists. The system control immediately enters FW (Freewheeling / rectification) mode. At this time, the motor back EMF is higher than the bus voltage, and current is injected into the bus capacitor and the power battery through the inverter's anti-parallel diodes (feedback charging).

[0036] The purpose of this step is to use the bus capacitor to absorb the instantaneous high energy in the motor stator winding, avoid direct short circuits that could cause excessive instantaneous current and burn out power devices, and also prevent voltage spikes from breaking down devices.

[0037] 2. Bus voltage monitoring and ASC switching (braking intervention phase): The MCU samples the bus voltage in real time at high frequency. When the bus voltage reaches a preset safety threshold, which is set according to the capacitor withstand voltage and the current speed, or when the charging time reaches a set duration (usually in milliseconds), the MCU determines that the energy discharge is complete and immediately switches to ASC (Active Short Circuit) mode.

[0038] The specific execution action is as follows: the MCU controls the inverter to turn on all three upper bridge arms or all three lower bridge arms, while keeping the three bridge arms on the opposite side completely off. At this time, the three-phase windings of the motor form a short-circuit closed loop internally.

[0039] 3. Maintain ASC state (lock-up anti-reverse phase): In ASC mode, the back electromotive force of the rotating motor generates a huge short-circuit current in the short-circuit winding. This current interacts with the magnetic field to produce a huge electromagnetic braking torque. This braking torque rapidly reduces the motor speed. When the motor speed drops to near zero or the back electromotive force falls below the bus voltage, the system does not exit ASC mode but is forced to remain in ASC state.

[0040] The mechanism of this step is as follows: At this time, the motor is in a state of high damping. If the residual pressure on the pump side attempts to drive the motor to reverse, a reverse induced current will be immediately generated in the motor winding due to the reverse trend, thereby generating a braking torque (dynamic damping torque) to counteract the reverse, "locking" the motor and pump shaft or limiting them to a very low speed until the residual pressure on the pump side is completely discharged, thus physically preventing the reverse from occurring.

[0041] III. Pump-side control While triggering FW mode, the MCU sends a high-priority fault command to the pump controller via the CAN bus. Upon receiving the fault signal, the pump controller quickly begins controlling the pump's flow rate. The controller sends a command to reduce the pump's speed to 0 rpm within 1 second, thus rapidly shutting off the pump's flow. This significantly reduces the residual pressure at the output. This allows the pump to shut off its flow output as quickly as possible, reducing residual pressure (i.e., by controlling the pump's displacement mechanism to quickly cut off the pressure source) and preventing pump reversal.

[0042] The specific execution method is as follows: After receiving a CAN fault message, the pump controller immediately opens the unloading valve and simultaneously sends the maximum current or cut-off current to the high-speed proportional solenoid valve that controls the pump swashplate angle, depending on the valve body's normally open / normally closed characteristics. This drives the solenoid valve to actuate rapidly, pushing the variable mechanism (such as a servo piston) to force the hydraulic pump's swashplate angle to zero. At this point, the pump's displacement becomes 0cc / rev, effectively cutting off the flow output and stopping the continuous pressure build-up at its source.

[0043] The solenoid valve response time (from receiving the electrical signal to the valve core actuating) is ≤15ms. The flow ramp descent gradient is ≥1000L / min / s (i.e., a step descent, not a smooth descent). The total execution time for quickly shutting off the pump flow (from the fault signal being issued to the flow returning to zero) is ≤50ms.

[0044] In some embodiments, the pump is an electronically controlled variable displacement piston pump. The specific execution method and technical principle (current control) are as follows: After receiving a high-priority fault frame (containing motor fault information) from the CAN bus, the pump controller immediately enters "emergency stop mode," immediately cutting off or adjusting the drive current output to the proportional solenoid valve of the piston pump. Under the action of the control current change, the servo mechanism inside the piston pump drives the swashplate to move rapidly. The swashplate tilt angle resets from the current operating angle to zero degrees (neutral position) in an extremely short time (milliseconds). When the swashplate tilt angle is zero, the pump's theoretical displacement becomes 0cc / rev. At this time, although the pump may still be rotating due to inertia from the motor, it no longer outputs hydraulic oil and no longer builds new pressure.

[0045] The pump controller's current response time from receiving the CAN signal to the output current jump is ≤10ms. The time for the piston pump swashplate to return from maximum displacement to zero displacement is ≤50ms. This depends on the pump's servo response characteristics, but is significantly faster than the natural pressure decay of a conventional hydraulic system.

[0046] The aforementioned "reducing residual pressure" refers to cutting off the supply source of high-pressure oil, so that the pressure on the pump outlet side no longer continues to rise. Combined with the ASC (Active Short Circuit) braking mode on the motor side, the electromagnetic braking torque generated by the motor is sufficient to overcome the reversing torque generated by the residual pressure in the pipeline, thereby achieving anti-reverse rotation.

[0047] The communication and interaction mechanism of the entire method in this invention is as follows: 1. MCU (Master Control Unit): After detecting a fault, it enters FW and ASC modes in sequence; at the same time, it sends a high-priority emergency stop command (including fault level flag) through the CAN bus.

[0048] 2. Pump controller (actuator): In listening mode, once an emergency stop command is parsed, it will directly execute the "swashplate zeroing" and "open unloading valve" actions without feedback confirmation.

[0049] 3. Vehicle Controller (VCU, optional coordinator): Monitors the status of the main control unit and the execution unit. If the MCU reports a fault but the pump pressure does not drop, the main relay can be disconnected as a secondary protection. The main relay is connected in series in the main power supply circuit from the vehicle's high-voltage power supply (such as the power battery) to the motor controller (MCU) / pump controller (or in the power circuit between the high-voltage power supply and the motor inverter and pump proportional solenoid valve). The specific logic is as follows: Normal operating condition: The main relay is closed, and the high-voltage power supply supplies power to the MCU, pump controller and actuators to ensure normal operation of the coordinated control; Abnormal operating conditions (such as the MCU reporting a fault but the pump pressure not dropping, indicating that the first-level protection has failed): After the VCU detects the abnormality, it sends a command to disconnect the main relay, interrupting the series power supply circuit. The MCU and pump controller lose high-voltage / control power, the motor inverter stops outputting, and the pump proportional solenoid valve cannot operate. This completely cuts off the power source after the motor locking torque fails, as well as the conditions for the continuous generation of pump residual pressure, thus realizing the second-level protection.

[0050] This invention can identify risks before physical reversal occurs by utilizing the microsecond-level computation cycle of the electronic control system. During the process of the rotational speed decreasing from forward to 0 rpm (a process that takes time), the MCU has already calculated the deceleration anomaly. Before the rotational speed crosses 0 rpm and becomes negative, the MCU determines that the "risk of reversal is extremely high" and forcibly enters and locks into ASC mode in advance. At this time, the electromagnetic braking torque generated by ASC manifests as static friction holding force near 0 rpm, directly "pressing" the rotor at the 0 rpm position, thus preventing physical reversal before it occurs.

[0051] The following comparative experiment will be conducted: I. Experimental testing process, methods, and environmental parameters 1. Test objective: By simulating a scenario where the motor suddenly fails (such as overcurrent) under high-speed and high-pressure conditions, the drop in motor speed and the magnitude of reversal are compared between the two states of "no anti-reverse control" and "using the cooperative control scheme of this invention" to verify the effectiveness of this scheme in preventing pump reversal.

[0052] 2. Test environment and key parameters: The test was conducted on a standard electro-hydraulic powertrain test bench, with the following key parameters: Test subject: A 50cc displacement plunger pump system driven by a high-speed motor.

[0053] Data acquisition system: DewesoftX professional data acquisition and analysis software (sampling frequency: 20kHz, ensuring the capture of transient changes).

[0054] Hydraulic medium: ISO VG 46 anti-wear hydraulic oil.

[0055] Oil temperature: controlled at 50±5℃ to simulate the actual working thermal balance state.

[0056] Bus capacitor specifications: 1100μF (film capacitor, rated voltage 800V).

[0057] Bus voltage: approximately 560V DC.

[0058] 3. Experimental steps: Step S1 (Engine Establishment): Control the motor to drive the pump to the target speed (5000 rpm) and load it to a high pressure state (180-200 bar).

[0059] Step S2 (Fault Trigger): Inject a fault signal (simulate overcurrent fault) to trigger system shutdown protection.

[0060] Step S3 (Group Testing): Control group: The fault was triggered only, the motor stopped naturally, and ASC and pump flow cut-off control were not activated.

[0061] Experimental group: After the fault is triggered, the motor mode control and pump flow zeroing collaborative control strategy of the present invention are immediately activated.

[0062] Step S4 (Data Recording): Record the maximum reverse rotation speed and the time for the speed to stabilize during the shutdown process.

[0063] The test results of the control group are as follows Figure 2 As shown, the test results of the experimental group are as follows: Figure 3 As shown.

[0064] II. Comparative Test Data and Attached Chart Analysis 1. Control group analysis Test conditions: initial pressure 200 bar, initial speed 5000 rpm, displacement 50 cc.

[0065] Waveform description: According to the appendix Figure 2 As shown, at the fault trigger point, the motor loses its driving force.

[0066] Due to the high pressure (200 bar) at the pump outlet, the motor speed drops rapidly and crosses zero under the enormous hydraulic reaction torque.

[0067] Key data: As shown in the upper right corner of the image, the measured speed dropped as low as -1504 rpm (the negative sign indicates reversal).

[0068] The entire out-of-control reversal process lasted 1.758 seconds.

[0069] Technical disadvantages: The reverse speed of up to -1500 rpm can cause severe cavitation at the pump suction port, damaging the distributor plate. Furthermore, prolonged reverse rotation means that the hydraulic system energy is released uncontrollably during the process, posing a great safety hazard.

[0070] 2. Analysis of the experimental group Test conditions: initial pressure 180 bar, initial speed 5000 rpm, displacement 50 cc. (Note: 180 bar and 200 bar are both high-pressure conditions and have equal reference value).

[0071] Waveform description: According to the appendix Figure 3 As shown, at the moment the fault is triggered, the MCU immediately performs anti-reverse control on the motor side, and at the same time the pump flow rate quickly returns to zero.

[0072] The green speed curve exhibits a "sudden braking" characteristic. Under the influence of the enormous electromagnetic braking torque generated by ASC, the motor speed is firmly "pulled" towards the zero axis.

[0073] Key data: As shown in the upper right corner of the figure, under the same inertia and pressure impact, the maximum reversal speed is only -22 rpm.

[0074] Summary of the phenomenon: It only took 0.02 seconds for the engine speed to drop from 5000 rpm to a stable state (close to 0 rpm).

[0075] Technical advantages: Improved reversal inhibition rate: Compared with the control group, the reversal speed decreased from -1504 rpm to -22 rpm, a reduction of 98.5%. -22 rpm is physically considered a micro-movement peristalsis, which does not constitute a substantial reversal and completely avoids mechanical damage.

[0076] Improved response speed: The shutdown stabilization time has been reduced from 1.758s to 0.02s, demonstrating the absolute speed advantage of electronically controlled ASC braking over mechanical hydraulic damping.

[0077] The above comparative experiments strongly demonstrate that the technical solution proposed in this invention, through the synergistic effect of active electromagnetic braking in motor ASC mode and pump flow cutoff, can rapidly overcome hydraulic counter-thrust within 20ms, limiting the reversal speed to a safe range. This not only solves the lag problem of reversal followed by stopping caused by reliance on check valves or passive damping in existing technologies, but also truly achieves the invention's objective of identifying and locking before physical reversal occurs.

[0078] The present invention has been described by way of example in conjunction with the accompanying drawings. Obviously, the specific implementation of the present invention is not limited to the above-described manner. Any non-substantial improvement made by adopting the inventive concept and technical solution of the present invention, or the direct application of the inventive concept and technical solution of the present invention to other occasions without modification, shall be within the protection scope of the present invention.

Claims

1. A method of controlling the combination of a motor and a pump to prevent the reverse rotation of a hydraulic pump, characterized by: include: The motor controller monitors the motor's operating status in real time; when a motor fault is detected, it performs anti-reverse control on the motor side and sends a fault signal to the pump's controller. The anti-reverse control on the motor side is as follows: The motor controller first controls the motor to switch to FW mode, using the motor back EMF to charge the bus capacitor; then, when the bus capacitor voltage reaches a preset threshold or the charging time reaches a set value, the controller controls the motor to switch to ASC mode, so that the motor stator winding forms a closed loop to generate electromagnetic braking torque; then, when the motor back EMF drops below the bus voltage, the controller controls the motor to maintain ASC mode, locking the motor shaft through electromagnetic braking torque. After receiving the fault signal, the pump controller immediately controls the hydraulic pump to perform a flow cut-off operation, cutting off the pressure supply source of the hydraulic pump, and cooperating with the electromagnetic braking torque on the motor side to prevent the hydraulic pump from reversing.

2. The method of claim 1, wherein the method further comprises: determining if the pump is rotating in a reverse direction; and if the pump is rotating in a reverse direction, then: stopping the pump; and restarting the pump in a forward direction. 2 The motor controller monitors the motor speed and estimates the torque in real time. When the motor is in a non-braking command state and the speed deceleration rate exceeds 500 rpm / s, or the speed approaches 0 rpm, if an unexpected reverse load torque is detected, the motor is determined to have failed, and the subsequent fault response process is triggered in advance.

3. The method of claim 1, wherein the method further comprises: determining if the pump is rotating in a reverse direction; and if the pump is rotating in a reverse direction, then: stopping the pump; and starting the pump in a forward direction. The FW mode is a freewheeling mode in which all three-phase rectifier circuits of the motor are disconnected, and the back electromotive force of the motor is fed back to the bus capacitor and the power battery through the inverter anti-parallel diode.

4. The method of claim 1, wherein the method further comprises: The ASC mode is implemented by controlling all three upper or lower bridge arms of the inverter to be turned on, while keeping the opposite three bridge arms off.

5. The method of claim 1, wherein the method further comprises: determining if the pump is rotating in a reverse direction; and if the pump is rotating in a reverse direction, then: stopping the pump; and re-starting the pump in a forward direction. The fault signal is a high-priority fault command, and its transmission method includes: assigning a low-value identifier to the CAN message carrying the fault information to obtain bus arbitration priority, and adopting an event triggering mechanism to immediately interrupt the transmission of regular messages and forcibly insert a fault message when a fault occurs.

6. The method of claim 1, wherein the method further comprises: The flow cut-off operation is as follows: the pump controller sends a control current to the solenoid valve of the hydraulic pump, driving the variable mechanism of the hydraulic pump to reduce the theoretical displacement of the pump to zero.

7. The method of claim 6, wherein the method further comprises: determining if the pump is rotating in a reverse direction; and if the pump is rotating in a reverse direction, then: stopping the pump; and re-starting the pump in a forward direction. The solenoid valve has a response time of ≤15ms, a flow ramp descent gradient of ≥1000L / min / s, and a total execution time from the issuance of the fault signal to the return of the flow to zero of ≤50ms.

8. The method of claim 1, wherein the method further comprises: The hydraulic pump is an electronically controlled variable displacement piston pump; after receiving the fault signal, the pump controller immediately cuts off or adjusts the drive current output to the proportional solenoid valve of the piston pump; under the action of the control current change, the servo mechanism inside the piston pump drives the swashplate to move rapidly; the swashplate tilt angle is reset to zero degrees from the current working angle within milliseconds.

9. The method of claim 1, wherein the method further comprises: determining if the pump is rotating in a reverse direction; and if the pump is rotating in a reverse direction, then: stopping the pump; and reversing the direction of rotation of the pump. The time taken for the motor speed to drop from the operating speed to a steady state is ≤20 milliseconds.

10. The method of claim 1, wherein the method further comprises: It also includes a vehicle controller, which monitors the operating status of the motor controller and the pump controller, and disconnects the main relay to achieve secondary protection in case of abnormality.

Images