Surge protection system

Abstract

This invention provides a voltage suppression protection system, comprising a motor circuit, a signal processing unit, a signal judgment unit, and a switching unit. The motor circuit is connected to a motor to drive it and outputs a current sampling signal. The signal processing unit is connected to the motor circuit to receive the current sampling signal and output a level signal. The signal judgment unit is connected to the signal processing unit to receive the level signal and includes a preset threshold. The switching unit is connected to the signal judgment unit and the motor circuit; the signal judgment unit obtains the real-time speed and average current of the motor based on the level signal and compares them with the speed threshold and current threshold, respectively. When the level signal exceeds the preset threshold, the motor is in a voltage suppression state, and a judgment signal is output to the switching unit to stop driving the motor.

Description

Technical Field

[0001] This invention relates to a pressure stagnation protection system, and more particularly to a pressure stagnation protection system that can accurately identify pressure stagnation conditions without the need for additional sensors. Background Technology

[0002] In existing water pump and fluid control technologies, common protection mechanisms are mainly designed to address overload or mechanical malfunctions. Common protection methods include overcurrent protection, stall protection, and temperature protection. Generally, when the water pump impeller seizes up or is overloaded, the drive current will rise sharply or the rotor will stop rotating. The control system can easily detect such abnormalities and cut off the power supply.

[0003] However, in practical applications, water pumps often face a special abnormal state known as dead-heading or blocked outlet. This state occurs when water is flowing normally into the inlet, but the outlet is completely closed or blocked. In this dead-heading state, because the pump cannot output flow, the fluid spins and rubs against itself inside the pump body, causing the mechanical load to decrease significantly compared to normal operation. According to fluid dynamics, when the load is reduced, the motor's operating current will decrease significantly (e.g., from a specific ampere value under normal load to an extremely low value), while the speed may remain high or only fluctuate slightly.

[0004] This low-current, high-speed characteristic is exactly the opposite of the triggering conditions (high current, zero speed) of traditional overcurrent or stall protection, making it difficult for existing drives to identify this fault through existing safety logic. If the system cannot detect the pressure buildup in real time and stop operation, the fluid trapped in the pump body will rapidly heat up due to the high-speed agitation of the impeller, and may even vaporize. Over time, this will lead to pump body structural deformation, shaft seal damage, or circuit board burnout due to heat accumulation.

[0005] Existing technologies use pressure sensors or flow switches to detect the water pressure status, but this increases hardware costs and system size, and the sensors are susceptible to failure due to fluid impurities. Other technologies attempt to estimate motor status through software, but lack correlation comparison with specific curves of current and speed, making them prone to misjudgments due to voltage fluctuations or electromagnetic interference, resulting in a lack of stability and consistency in both verification and practical applications. Therefore, the industry urgently needs a protection technology that can accurately identify pressure buildup conditions using only the motor's own drive parameters without additional sensors, and includes a logical verification mechanism. Summary of the Invention

[0006] The purpose of this invention is to provide a pressure buildup protection system to solve the technical problem of difficulty in effectively detecting pressure buildup in existing water pump and fluid machinery control technologies. Because the motor exhibits low current and high speed operating characteristics under pressure buildup, which is drastically different from the high current characteristics of traditional overcurrent or stall protection, existing drives often fail to identify it in real time, leading to serious damage such as fluid heating and vaporization, mechanical deformation, or circuit burnout.

[0007] To achieve the above objectives, the present invention provides a voltage suppression protection system, comprising a motor circuit, a signal processing unit, a signal judgment unit, and a switching unit. The motor circuit is electrically connected to a motor to drive the motor and output a current sampling signal. The signal processing unit is electrically connected to the motor circuit to receive the current sampling signal and process it to output at least one quasi-signal. The signal judgment unit is electrically connected to the signal processing unit to receive the at least one quasi-signal and includes at least one preset threshold. The switching unit is electrically connected to the signal judgment unit and the motor circuit. The signal judgment unit obtains a real-time speed and an average current of the motor based on the at least one quasi-signal and compares the real-time speed and the average current with the speed threshold and the current threshold, respectively. When the at least one quasi-signal exceeds the at least one preset threshold, the signal judgment unit determines that the motor is in a voltage suppression state and outputs a judgment signal to the switching unit to control the motor circuit to stop driving the motor.

[0008] The aforementioned pressure-locking protection system can sample and calculate the motor's speed and current values ​​in real time during motor operation. When a specific state of high speed and low current is detected, it is determined to be a pressure-locking fault with the outlet closed. Once pressure-locking is confirmed, the motor's drive power is cut off through the switching unit, or the system enters a protection lockout mode, thereby preventing the water pump from overheating and burning out due to prolonged idling or pressure-locking. Attached Figure Description

[0009] Figure 1 This is a block diagram of the components of the pressure stagnation protection system of the present invention;

[0010] Figure 2 This is a flowchart of the pressure suffocation protection detection process of the present invention;

[0011] Figure 3 This is a schematic diagram of the interruption process of the pressure stagnation protection method of the present invention; and

[0012] Figure 4 This is a block diagram of the Field Direction Control (FOC) module inside the signal processing unit in the pressure protection system of the present invention.

[0013] Figure reference numerals: 10-Overpressure protection system; 11-Motor circuit; 12-Signal processing unit; 13-Signal judgment unit; 131-Speed ​​comparison module; 132-Current comparison module; 133-Logic judgment module; 14-Switch unit; S201~S208-Steps; 301-Drive interrupt service routine; 302-System time base parameters; 401-Coordinate transformation unit; 402-Estimator; 403-Loop controller. Detailed Implementation

[0014] The above-mentioned objectives and structural and functional characteristics of the present invention will be described with reference to the preferred embodiments shown in the accompanying drawings. It should be specifically noted that the present invention is not limited to the structural forms provided in the following embodiments, and those skilled in the art can make appropriate changes without departing from the spirit and scope of the present invention.

[0015] Figure 1 This is a block diagram of the components of the overpressure protection system of the present invention, as shown below. Figure 1 As shown, the overvoltage protection system 10 of the present invention mainly includes a motor circuit 11, a signal processing unit 12, a signal judgment unit 13, and a switching unit 14. In a preferred embodiment of the present invention, the motor circuit 11 is composed of a power switching element, a current sampling resistor, and a voltage divider circuit, used to drive the motor and provide current and voltage signals that reflect the operating status of the motor. When the motor circuit 11 is running, the three-phase current forms a current sampling signal through the sampling resistor.

[0016] The signal processing unit 12 and the signal judgment unit 13 are preferably composed of a microcontroller (MCU). The signal processing unit 12 is electrically connected to the motor circuit 11 and is used to receive the current sampling signal. The signal processing unit 12 adjusts the current sampling signal to the measurable range of the microcontroller's analog-to-digital converter (ADC). The current sampling signal after voltage division is then appropriately gain-adjusted and filtered by the signal amplification circuit in the signal processing unit 12, and then outputs a quasi-bit signal. The signal processing unit 12 improves the signal quality and suppresses electromagnetic noise, so that it can more accurately reflect the real-time operating status of the motor.

[0017] The signal judgment unit 13 is electrically connected to the signal processing unit 12. The signal judgment unit 13 is used to receive the level signal output by the signal processing unit 12. In a preferred embodiment of the present invention, the level signal mainly includes the average current signal representing the operating load of the motor and the speed signal representing the operating speed. Since motors of different specifications or models have different mechanical characteristics and electrical characteristics (e.g., the speed-torque curve and flow-current curve are different), the preset judgment conditions on which the signal judgment unit 13 operates are preset or adjusted according to the operating characteristics of the specific motor connected to it. These conditions include a set of current thresholds and speed thresholds corresponding to the normal operating range of the motor.

[0018] Specifically, the signal judgment unit 13 preferably includes a speed comparison module 131 and a current comparison module 132, which compare the estimated level signal (e.g., speed and average current) with their corresponding preset thresholds. These preset thresholds are determined based on the motor characteristic curve of the motor under normal load operation. For example, the current threshold represents the minimum normal operating current value that the motor should have according to the motor characteristic curve when operating corresponding to the speed threshold. Furthermore, when the speed comparison module 131 detects that the real-time speed signal is higher than or equal to the speed threshold, it outputs a first comparison result, and when the current comparison module 132 simultaneously determines that the average current signal is lower than the current threshold (i.e., exhibiting a low load characteristic of high speed and low current that deviates from the motor characteristic curve), it outputs a second comparison result. The logic judgment module 133 is connected to the speed comparison module 131 and the current comparison module 132. The logic judgment module 133 of the signal judgment unit 13 receives the first comparison result and the second comparison result and outputs a voltage judgment signal to the switching unit 14. The switching unit 14 controls the driving state of the motor circuit 11 based on the pressure stagnation determination signal, so that the system can temporarily stop the motor operation when the pressure stagnation state is detected.

[0019] To ensure the reliability of the judgment and eliminate temporary fluctuations, after entering the overpressure protection state, the signal judgment unit 13 calculates a waiting time in the microcontroller's interrupt procedure, and after the waiting time ends, controls the switch unit 14 to restart the motor to confirm whether the abnormality has been resolved. If the abnormal state persists after restarting, the system will repeat the above restart procedure according to a preset number of times; when the number of restarts reaches the upper limit, the signal judgment unit 13 will determine that the fault is confirmed, and the system will enter the protection lockout state. At this time, it is necessary to restart the power supply or issue an unlock command from the host computer before operation can be restored.

[0020] As described above, the pressure buildup protection system 10 of the present invention can detect the pressure buildup caused by the closure of the water outlet by relying on the current signal provided by the motor circuit 11 and the calculation results of the microcontroller's internal field-oriented control (FOC) module, without adding additional sensors (such as pressure or flow sensors). This design can complete the judgment process in a modular manner, and can achieve the protection and control effect by restarting for confirmation.

[0021] Figure 2 The flowchart of the pressure suffocation protection detection method of the present invention is as follows: Figure 2 As shown, in step S201, a set of overvoltage protection thresholds is set based on the characteristic curve of the motor, which includes at least a current threshold and a speed threshold. The current threshold is the lowest normal operating current value at different speeds, and the speed threshold is the lower speed limit required to determine the overvoltage state. In step S201, the judgment criteria can meet the load characteristics of different motors. The overvoltage protection threshold is determined based on the motor characteristic curve of the motor under normal load operation. For example, the current threshold represents the lowest normal operating current value that the motor should have according to the motor characteristic curve when operating corresponding to the speed threshold.

[0022] Next, in step S202, a signal processing unit 12 detects the current sampling signal of the motor circuit 11. This current sampling signal is filtered, digitized, and processed by the signal processing unit 12 to generate a level signal (or state parameter) containing real-time speed and average current. It should be noted that although this embodiment uses speed and current as the basis for judgment, in different embodiments, the signal processing unit 12 can also deduce other operating characteristics of the motor (such as power or load duty cycle) based on the current sampling signal; this is not a limitation.

[0023] Subsequently, in step S203, the signal judgment unit 13 compares the detected signal with the threshold set in step S201 to determine whether the overvoltage condition of the estimated speed being higher than the speed threshold and the average current being lower than the current threshold is met. If the judgment result is yes, the overvoltage protection in step S204 is entered, controlling the motor circuit 11 to stop operating and start timing and waiting. If the judgment result is no, the process returns to step S202 to continue detecting the real-time speed and average current signal of the motor circuit 11.

[0024] Furthermore, in step S204, the purpose of stopping the control motor circuit 11 and starting a timer is to provide real-time protection. When the pressure buildup protection system 10 detects high speed and low current, it indicates that the cooling water flow is obstructed and internal heat is accumulating. At this time, immediately cutting off the drive power to stop the motor directly prevents the pump body from generating high temperatures due to the high-speed agitation of the fluid by the impeller, thus avoiding mechanical deformation or circuit damage. At the same time, starting the timer and introducing a preset buffer waiting time (e.g., several seconds) is to allow any fluid disturbances or electrical transients in the pipeline to stabilize and serves as a prerequisite for subsequent restart confirmation. Through this rest period, the system can ensure that the subsequent restart detection is performed on a stable baseline, rather than being misjudged due to noise interference or unstable oscillation signals.

[0025] After the waiting time ends, step S205 determines whether the protection time and restart count have reached the preset upper limit. The purpose of step S205 is to perform a secondary confirmation of the fault state to eliminate temporary interference and ensure the accuracy of the protection action. In actual operating environments, water bubbles, instantaneous voltage fluctuations, or electromagnetic noise interference can all cause the sensing signal to momentarily meet the pressure stagnation characteristics. If the system triggers a permanent shutdown based on a single detection result, it will cause unnecessary operational interruptions and inconvenience. Therefore, this invention confirms the end of the protection time to allow the motor and fluid state to stabilize, eliminating interference caused by temporary water disturbances or electrical noise. Determining the upper limit of the restart count is used to verify the persistence of the abnormal state. Through the above-mentioned time waiting and count check, the system can effectively distinguish between occasional fluctuations and real faults, ensuring the accuracy of subsequent locking protection actions.

[0026] If the upper limit is not reached, a restart is performed in step S206 and the count is incremented. Then, the system returns to step S202 to continue monitoring. If the upper limit has been reached, it means that the abnormality continues. The system enters the protection lock state in step S207, which keeps the motor stopped until step S208 receives a power reset or host computer unlock command, at which point the lock can be cleared and operation can be resumed.

[0027] In conclusion, the pressure buildup protection method of this invention eliminates the need for additional pressure or flow sensors. It achieves low-cost and high-accuracy anomaly detection solely through the speed and current signals fed back from the motor drive circuit. By comparing specific load characteristics of "high speed, low current" and combining this with secondary confirmation logic based on protection waiting time and restart count upper limit, this invention effectively eliminates misjudgments caused by water circuit disturbances or electrical noise, accurately identifying the true fault of a closed water inlet. This mechanism ensures that the water pump can forcibly enter lockout protection after confirming a pressure buildup state, preventing mechanical deformation and circuit burnout caused by fluid stagnation and temperature rise or prolonged motor idling, thereby significantly improving the overall reliability and service life of the product.

[0028] Figure 3 This is a schematic diagram of the interruption process of the pressure buildup protection method of the present invention. Figure 3 As shown, for example, in the interrupt process of the overvoltage protection method, an interrupt request is used to trigger the drive interrupt service routine (DRV_ISR) 301, and the motor current sampling and overvoltage characteristic comparison are performed in real time in the interrupt service routine; at the same time, a fixed-period interrupt signal is generated to update a system time base parameter (TickCycle_) 302. When the microcontroller determines that an overvoltage abnormality has occurred, it performs filtering confirmation based on the accumulated time length of the system time base parameter (TickCycle_). If the confirmation is correct, the system is forced to jump out of the normal operation mode and enter the locked protection state in the main loop (WHILE(1)). The above is only to illustrate how the overvoltage protection method of the present invention executes the motor interrupt request in FOC, and is not intended to limit the interrupt request of the present invention to only be executed in the above-mentioned field-guided control (FOC) mode, and is not limited here.

[0029] Figure 4 This is a block diagram of the Field Direction Control (FOC) module inside the signal processing unit in the pressure suppression protection system of the present invention. Figure 4 As shown, the Field Direction Control (FOC) module includes at least a coordinate transformation unit 401, an estimator 402, and a loop controller 403. The coordinate transformation unit (CLARKE and PARK) 401 is responsible for converting the three-phase current sampling signals of the motor into flux current components (ID) and torque current components (IQ). The estimator (THETA_OUT) 402 calculates the real-time angle (THETA) of the motor rotor based on the current and voltage signals for coordinate transformation, and simultaneously calculates the estimated rotational speed (EOME). The back-end loop controller (PI and SVPWM) 403 performs closed-loop control of the motor based on the aforementioned calculation results. In the overvoltage protection application of this invention, the signal judgment unit directly compares the estimated rotational speed (EOME) output by the estimator 402 with the torque current component (IQ, corresponding to the average current) calculated by the coordinate transformation unit to determine whether an overvoltage fault has occurred.

[0030] In summary, the pressure buildup protection system of this invention monitors the motor in real time through a signal processing unit and performs logical operations using a signal judgment unit. This invention can sample and calculate the motor's speed and current values ​​in real time during motor operation; when a specific state of high speed and low current is detected, it is determined to be a pressure buildup fault with the outlet closed. Once pressure buildup is confirmed, this invention immediately cuts off the motor's drive power supply through a switching unit or enters a protection lockout mode, thereby preventing the water pump from overheating and burning out due to prolonged idling or pressure buildup.

[0031] The present invention has been described in detail above. However, the above description is only a preferred embodiment of the present invention and should not be construed as limiting the scope of the present invention. All equivalent variations and modifications made in accordance with the claims of the present invention should still fall within the scope of the present invention.

Claims

1. A pressure containment protection system, characterized in that, Include: A motor circuit is electrically connected to a motor to drive the motor and output a current sampling signal. A signal processing unit, electrically connected to the motor circuit, is used to receive the current sampling signal and process the current sampling signal to output at least one bit of quasi-signal; A signal determination unit, electrically connected to the signal processing unit, is used to receive the at least one quasi-signal. The signal determination unit includes at least one preset threshold and compares the at least one quasi-signal with the at least one preset threshold. A switching unit is electrically connected to the signal judgment unit and the motor circuit; When the at least one quasi-signal exceeds the at least one preset threshold, the signal judgment unit determines that the motor is in a sluggish state and outputs a judgment signal to the switching unit to control the motor circuit to stop driving the motor.

2. The overpressure protection system of claim 1, wherein, The at least one quasi-signal is a real-time speed value and / or an average current value, and the at least one preset threshold is a speed threshold and / or a current threshold. When the signal judgment unit determines that the real-time speed value is greater than the speed threshold and the average current value is less than the current threshold, it determines that the at least one quasi-signal exceeds the preset threshold and is in the suffocation state.

3. The overpressure protection system of claim 2, wherein, The signal determination unit includes: A speed comparison module is used to compare the real-time speed with the speed threshold and output a first comparison result; A current comparison module is used to compare the average current with the current threshold and output a second comparison result; as well as A logic determination module is electrically connected to the speed comparison module and the current comparison module to receive the first comparison result and the second comparison result, and output the determination signal to the switching unit.

4. The overpressure protection system of claim 2, wherein, The speed threshold and the current threshold are set based on the speed-current characteristic curve of the motor under normal load, and the current threshold is set as the minimum normal operating current value of the motor under the speed threshold.

5. The overpressure protection system of claim 2, wherein, The current sampling signal is the phase current and / or average current of the motor.

6. The overpressure protection system of claim 1, wherein, When the signal judgment unit outputs the judgment signal, the signal judgment unit controls the pressure stagnation protection system to enter a waiting state, and after a waiting time, controls the switching unit to restart the motor.

7. The overpressure protection system of claim 6, wherein, The signal judgment unit accumulates a restart count; if the restart count does not reach an upper limit, the restart is executed; if the restart count reaches the upper limit and the pressure buildup still exists, the signal judgment unit controls the pressure buildup protection system to enter a protection lockout state and forces the switch unit to remain stopped driving the motor.

8. The pressure stagnation protection system as described in claim 7, characterized in that, When the pressure relief protection system is in the protection lockout state, the signal judgment unit continuously detects whether an unlocking command is received; when the unlocking command is received, the signal judgment unit clears the restart count and releases the protection lockout state to restore the drive and detection of the motor.

9. The pressure stagnation protection system as described in claim 1, characterized in that, The signal processing unit and the signal judgment unit are composed of a microcontroller, which includes a magnetic field guidance control module.

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