A power load dynamic allocation system for smart factory flexible logistics production line

Abstract

The application relates to the technical field of intelligent factory power supply and distribution control, and discloses a power load dynamic distribution system for an intelligent factory flexible logistics production line, which comprises a busbar electrical parameter acquisition unit, a line impedance calculation unit and a load access control unit. The busbar electrical parameter acquisition unit acquires busbar parameters and identifies current steps. The line impedance calculation unit uses step responses to update system equivalent impedance in real time. The load access control unit estimates voltage drop caused by a to-be-accessed load based on the impedance and allows the load to start only when the remaining voltage meets safety constraints. The application can capture load mutations to obtain power grid physical impedance characteristics in real time, establish an active access mechanism based on physical stability boundaries, avoid voltage collapse risks caused by random impulse loads, and improve the dynamic bearing capacity and operation stability of the flexible production line power distribution system.

Description

Technical Field

[0001] This invention relates to a dynamic power load distribution system for flexible logistics production lines in smart factories, belonging to the field of power supply and distribution control technology for smart factories. Background Technology

[0002] Currently, in the construction of existing smart factory flexible logistics production lines, the design of power supply and distribution systems generally follows the demand factor method or the static capacity summation method. The core logic is to multiply the total rated power of all electrical equipment in the production line, such as elevators, stacker cranes, and sorting trolleys, by an empirical simultaneity factor to select the transformer capacity and cable specifications. During operation, conventional power distribution protection devices mainly rely on the thermal-magnetic tripping of circuit breakers or the overcurrent threshold of electronic protection units to cut off overload or short-circuit faults. However, as logistics production lines evolve towards higher flexibility and faster cycles, this static model-based and post-event protection approach is becoming increasingly ineffective. Traditional power supply architectures exhibit severe fundamental limitations when facing large-scale random concurrent loads. Existing technologies typically assume that the system impedance of the power supply circuit is constant and extremely low, using only the fact that the power value does not exceed the rated value as a safety criterion. However, in actual operating conditions, topology switching of the upstream power grid, temperature rise changes in transformer windings, and random drift of the contact resistance of long-distance sliding contact lines cause the Thevenin equivalent impedance of the power supply circuit to change over time. When the system impedance unexpectedly increases due to environmental factors, i.e., the power grid softens, even if the current load power is within the theoretical rated range, the starting moment of the next heavy-load motor will still produce an unexpected voltage drop.

[0003] Existing impedance detection technologies, even those that incorporate dynamic calculation methods, struggle to match the transient characteristics of flexible production lines in their application scenarios and control logic. For instance, Chinese invention patent CN111208351B discloses a method and storage medium for calculating power line impedance based on load transitions. While this approach proposes using load transitions to invert impedance, its core concept focuses on monitoring and identifying chronic anomalies such as line aging or electricity theft through long-cycle impedance data monitoring. Essentially, it's a post-event diagnosis over a long timescale. Faced with the millisecond-level concurrent startup impact of smart factories, such technologies lack the mechanism to convert real-time impedance into pre-access arbitration conditions. The system cannot predict the voltage drop magnitude instantaneously before the motor is powered on, making it difficult for the control system to proactively avoid risks using this parameter. More importantly, the protection mechanism has a lag in response time. Traditional overcurrent protection is a passive disconnection after a fault occurs. In flexible production lines, the millisecond-level current surge caused by the simultaneous acceleration of multiple variable frequency drive devices can cause the bus voltage to drop instantaneously below the undervoltage lockout threshold of sensitive electronic devices such as programmable logic controllers, sensors, or servo drives. At this time, the relay protection device has not yet acted, but the control system has already undergone a logic reset or communication interruption due to voltage instability, causing the production line to shut down in a non-faulty state.

[0004] Therefore, the technical problem to be solved by this invention is how to obtain the dynamic physical impedance characteristics of the power supply circuit in real time without adding expensive power grid analysis instruments, and construct a predictive voltage stability defense boundary accordingly, so as to achieve dynamic and accurate matching between process load and power distribution capacity. Summary of the Invention

[0005] To address the problems mentioned in the background art, the technical solution of the present invention is as follows: A dynamic power load distribution system for flexible logistics production lines in smart factories, comprising: The bus electrical parameter acquisition unit is physically connected to the common bus of the power distribution circuit. It is used to acquire the instantaneous value of the bus voltage and the instantaneous value of the total circuit current of the common bus in real time at a preset sampling frequency, and to detect the current step change caused by the start and stop of uncontrolled loads in the logistics production line. The line impedance calculation unit is connected to the bus electrical parameter acquisition unit. It is used to respond to the current step change, obtain the bus voltage change within the change time window, and update the system equivalent impedance value, which represents the physical connection state of the current power supply circuit, in real time based on the ratio of the bus voltage change to the current step change amplitude that caused the change. The load access control unit is connected to the line impedance calculation unit and multiple controlled load controllers on the logistics production line. When a power access request is received from any controlled load, the control unit executes voltage stability judgment logic: based on the latest system equivalent impedance value and the expected current increment requested by the controlled load, it calculates the estimated bus voltage drop at the time of the controlled load access; if the value of the current instantaneous bus voltage minus the estimated bus voltage drop is not lower than the preset minimum operating voltage threshold, it outputs a closing command to allow the controlled load to start; if it is lower than the minimum operating voltage threshold, it outputs an adjustment command to control the controlled load to perform power limiting or delayed start.

[0006] Preferably, the line impedance calculation unit further includes a disturbance amplitude filtering module, which compares the absolute value of the amplitude of the monitored current step change with a preset current change dead zone threshold; when the absolute value of the amplitude of the current step change is greater than the current change dead zone threshold, the line impedance calculation unit performs an update calculation of the system equivalent impedance value; the line impedance calculation unit uses a weighted average algorithm to process the instantaneous impedance value obtained in this calculation with the historically stored impedance value to generate the system equivalent impedance value used for this determination.

[0007] Preferably, the system further includes: a power balance control unit connected to the common bus and a frequency converter drive device with regenerative braking function; the power balance control unit is used to monitor the voltage rise rate of the common bus, and when it detects that the bus voltage caused by regenerative braking energy exceeds a preset overvoltage consumption threshold, it generates a priority start command for the heavy-load equipment in the same power distribution circuit that is in standby mode; the priority start command is used to control the heavy-load equipment to start during the regenerative braking energy feedback period, thereby suppressing the rise of bus voltage by consuming regenerative braking energy.

[0008] Preferably, the voltage stability determination logic executed by the load connection control unit follows the following inequality relationship: ,in, The instantaneous value of the current voltage of the common bus is collected. Let be the real part of the system's equivalent impedance. The expected current increment requested by the controlled load. The minimum operating voltage threshold is preset; the load connection control unit only outputs a closing command when the above inequality is true.

[0009] Preferably, the load access control unit includes a power level matching module, which is used to select a target power level from a plurality of preset power levels based on the current voltage margin when the estimated bus voltage drop causes the calculated result to be lower than the minimum operating voltage threshold, so that the estimated bus voltage recalculated based on the target power level meets the minimum operating voltage threshold, and to send the target power level to the controlled load controller in the adjustment command.

[0010] Preferably, the bus electrical parameter acquisition unit further includes a current spectrum analysis module, which is used to perform spectrum transformation on the acquired instantaneous value of the total loop current and extract the current ripple amplitude of a specific frequency band; the load access control unit is used to compare the extracted current ripple amplitude with a preset abnormal characteristic threshold. If it exceeds the abnormal characteristic threshold, the calculation weight of the corresponding controlled load in the calculation of the estimated bus voltage drop is increased to increase the retention margin of voltage stability.

[0011] Preferably, the system adopts a multi-level control architecture. The load access control unit includes a main controller located on the transformer outgoing line side and several sub-controllers located on the branch bus side. The main controller is used to process the power access request of the main line based on the system equivalent impedance of the main line, and the sub-controllers are used to process the power access request of the branch load based on the local system equivalent impedance of the branch circuit. The sub-controllers are configured to send a closing command to the controlled load connected to them only after receiving the permission signal from the main controller.

[0012] Preferably, the line impedance calculation unit is also used to maintain a historical impedance database, which stores time-impedance data records corresponding to different production line sections; the load access control unit is used to call the historical impedance data corresponding to the current time period in the historical impedance database as an estimated value during the quiet period when the current uncontrolled load does not operate, and to execute the voltage stability judgment logic.

[0013] Preferably, the controlled load controller is used to start a delay timer after receiving an adjustment command requiring delayed start-up. The duration of the delay timer is determined based on the sum of a preset reference time and a random deviation value. The load access control unit is used to set different preset reference times according to the process type identifier of the controlled load, so that the preset reference time of high-priority process equipment is less than the preset reference time of low-priority auxiliary equipment.

[0014] Preferably, the bus electrical parameter acquisition unit, the line impedance calculation unit, and the load access control unit are integrated into an industrial power distribution control terminal; the industrial power distribution control terminal directly acquires the voltage and current signals of the common bus through a hard-wired interface, and connects to the controlled load controller through an industrial fieldbus to transmit closing commands or adjustment commands.

[0015] Compared with the prior art, the beneficial effects of the present invention are: 1. In dynamic power load distribution, based on the dynamic inversion and adaptive defense of power supply circuit impedance excited by load disturbance, this invention constructs a physical parameter sensing mechanism that uses load mutations in the production process as detection signals. Within the transient window after the arbitration control unit issues the load start command, the bus status monitoring unit synchronously collects the voltage drop difference and current step increment of the distribution bus, and calculates the real-time equivalent system impedance of the power supply circuit accordingly. Utilizing the physical characteristics of motor starting in the logistics production line, it inverts the comprehensive physical impedance parameters in real time, including transformer winding temperature rise, cable contact resistance aging, and upstream grid topology switching. The arbitration control unit dynamically adjusts the power access boundary based on the real-time impedance to ensure that the start permission of high-power loads is automatically tightened when the power supply circuit impedance increases or the grid carrying capacity decreases. This closed-loop control based on physical measurement solves the technical contradiction in traditional power distribution design that relies solely on static rated capacity for management and cannot cope with system parameter drift, ensuring the voltage stability of the distribution bus throughout its entire life cycle and preventing undervoltage shutdown faults caused by line aging or poor contact.

[0016] 2. Predictive matching of process feature feedforward mapping and voltage stability boundary: This invention converts non-electrical process step sequence signals into expected current demand values ​​for electrical quantities through a power feature mapping unit, and completes the matching arbitration with the power supply capacity before the physical current is generated. The arbitration control unit combines the real-time inverted system impedance and expected current demand to calculate the bus voltage drop that may be caused by the instantaneous load connection, and uses this as the basis for generating execution instructions. This logic advances the response sequence of power distribution protection from post-overcurrent cut-off to pre-access assessment, eliminating the physical lag of traditional circuit breakers or electronic protection units when responding to faults. By avoiding concurrent load requests that may cause the bus voltage to drop below the safety threshold at the control level, the continuity and stability of the power supply voltage of sensitive electronic equipment are ensured at the physical level, avoiding logic reset or communication interruption caused by transient voltage fluctuations.

[0017] 3. Spatiotemporal Coordination and Hedging Mechanism of Energy Flow and Information Flow: This invention utilizes the pre-stored regenerative power characteristic items in the power characteristic mapping unit to establish a temporal coupling logic between negative power events and consumable loads. The arbitration control unit identifies process steps with regenerative braking attributes and superimposes the regenerative power value when calculating the available power margin to generate an extended power margin. Based on this, the system schedules heavy-load tasks and regenerative braking tasks in the waiting queue to be executed concurrently within the overlapping time window, guiding the feedback energy to be directly supplied to consumable loads on the DC bus side. This energy hedging mechanism based on time-series planning utilizes the frequent start-stop characteristics of equipment in flexible logistics production lines to achieve self-balancing of power flow within the local power distribution circuit, reducing the instantaneous peak load demand of transformers and main cables, suppressing the bus voltage rise caused by energy feedback, and improving the physical carrying capacity of the power distribution system for concurrent high-throughput tasks while reducing the heat dissipation of braking resistors. Attached Figure Description

[0018] Figure 1 This is a block diagram illustrating the overall control architecture and signal interaction principle of the present invention. Figure 2 This is a flowchart illustrating the logic for determining the load connection voltage stability of the dynamic impedance according to the present invention.

[0019] The objectives, features, and advantages of this invention will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0020] The technical solutions of the embodiments of this application will be clearly described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of this application are within the scope of protection of this application.

[0021] A dynamic power load distribution system for flexible logistics production lines in smart factories includes: The bus electrical parameter acquisition unit is physically connected to the common bus of the power distribution circuit. It is used to acquire the instantaneous value of the bus voltage and the instantaneous value of the total circuit current of the common bus in real time at a preset sampling frequency, and to detect the current step change caused by the start and stop of uncontrolled loads in the logistics production line. The line impedance calculation unit is connected to the bus electrical parameter acquisition unit. It is used to respond to the current step change, obtain the bus voltage change within the change time window, and update the system equivalent impedance value, which represents the physical connection state of the current power supply circuit, in real time based on the ratio of the bus voltage change to the current step change amplitude that caused the change. The load access control unit is connected to the line impedance calculation unit and multiple controlled load controllers on the logistics production line. When a power access request is received from any controlled load, the control unit executes voltage stability judgment logic: based on the latest system equivalent impedance value and the expected current increment requested by the controlled load, it calculates the estimated bus voltage drop at the time of the controlled load access; if the value of the current instantaneous bus voltage minus the estimated bus voltage drop is not lower than the preset minimum operating voltage threshold, it outputs a closing command to allow the controlled load to start; if it is lower than the minimum operating voltage threshold, it outputs an adjustment command to control the controlled load to perform power limiting or delayed start.

[0022] Preferably, the line impedance calculation unit further includes a disturbance amplitude filtering module, which compares the absolute value of the amplitude of the monitored current step change with a preset current change dead zone threshold; when the absolute value of the amplitude of the current step change is greater than the current change dead zone threshold, the line impedance calculation unit performs an update calculation of the system equivalent impedance value; the line impedance calculation unit uses a weighted average algorithm to process the instantaneous impedance value obtained in this calculation with the historically stored impedance value to generate the system equivalent impedance value used for this determination.

[0023] Preferably, the system further includes: a power balance control unit connected to the common bus and a frequency converter drive device with regenerative braking function; the power balance control unit is used to monitor the voltage rise rate of the common bus, and when it detects that the bus voltage caused by regenerative braking energy exceeds a preset overvoltage consumption threshold, it generates a priority start command for the heavy-load equipment in the same power distribution circuit that is in standby mode; the priority start command is used to control the heavy-load equipment to start during the regenerative braking energy feedback period, thereby suppressing the rise of bus voltage by consuming regenerative braking energy.

[0024] Preferably, the voltage stability determination logic executed by the load connection control unit follows the following inequality relationship: ,in, The instantaneous value of the current voltage of the common bus is collected. Let be the real part of the system's equivalent impedance. The expected current increment requested by the controlled load. The minimum operating voltage threshold is preset; the load connection control unit only outputs a closing command when the above inequality is true.

[0025] Preferably, the load access control unit includes a power level matching module, which is used to select a target power level from a plurality of preset power levels based on the current voltage margin when the estimated bus voltage drop causes the calculated result to be lower than the minimum operating voltage threshold, so that the estimated bus voltage recalculated based on the target power level meets the minimum operating voltage threshold, and to send the target power level to the controlled load controller in the adjustment command.

[0026] Preferably, the bus electrical parameter acquisition unit further includes a current spectrum analysis module, which is used to perform spectrum transformation on the acquired instantaneous value of the total loop current and extract the current ripple amplitude of a specific frequency band; the load access control unit is used to compare the extracted current ripple amplitude with a preset abnormal characteristic threshold. If it exceeds the abnormal characteristic threshold, the calculation weight of the corresponding controlled load in the calculation of the estimated bus voltage drop is increased to increase the retention margin of voltage stability.

[0027] Preferably, the system adopts a multi-level control architecture. The load access control unit includes a main controller located on the transformer outgoing line side and several sub-controllers located on the branch bus side. The main controller is used to process the power access request of the main line based on the system equivalent impedance of the main line, and the sub-controllers are used to process the power access request of the branch load based on the local system equivalent impedance of the branch circuit. The sub-controllers are configured to send a closing command to the controlled load connected to them only after receiving the permission signal from the main controller.

[0028] Preferably, the line impedance calculation unit is also used to maintain a historical impedance database, which stores time-impedance data records corresponding to different production line sections; the load access control unit is used to call the historical impedance data corresponding to the current time period in the historical impedance database as an estimated value during the quiet period when the current uncontrolled load does not operate, and to execute the voltage stability judgment logic.

[0029] Preferably, the controlled load controller is used to start a delay timer after receiving an adjustment command requiring delayed start-up. The duration of the delay timer is determined based on the sum of a preset reference time and a random deviation value. The load access control unit is used to set different preset reference times according to the process type identifier of the controlled load, so that the preset reference time of high-priority process equipment is less than the preset reference time of low-priority auxiliary equipment.

[0030] Preferably, the bus electrical parameter acquisition unit, the line impedance calculation unit, and the load access control unit are integrated into an industrial power distribution control terminal; the industrial power distribution control terminal directly acquires the voltage and current signals of the common bus through a hard-wired interface, and connects to the controlled load controller through an industrial fieldbus to transmit closing commands or adjustment commands.

[0031] Example 1: This example is applied to the power distribution environment of an automated warehouse in a smart factory. A main transformer with a rated capacity of 1600kVA supplies power to multiple stacker cranes and conveyor rollers via a common busbar. When the physical connection of the power supply circuit changes due to wear of the sliding contact line shoes and switching operations at the upstream substation, causing the system's equivalent impedance to be higher than the initial design value, the busbar electrical parameter acquisition unit collects the instantaneous busbar voltage value of the common busbar in real time at a sampling frequency of 10kHz. The instantaneous value of the total circuit current is calculated. When a current step change of 30A is detected caused by the start-up of an uncontrolled auxiliary sorting motor in the production line, the line impedance calculation unit locks the change time window, extracts the bus voltage change, and updates the system equivalent impedance value, which characterizes the current physical connection state of the power supply circuit, in real time based on the ratio of the bus voltage change to the current step change amplitude. The real part of this value is recorded as... When a controlled heavy-duty stacker crane with a rated power of 45kW sends a current increment of 220A to the system When a power access request is received, the load access control unit executes the voltage stability determination logic.

[0032] The load connection control unit reads the latest system equivalent impedance value. and the current instantaneous value of bus voltage ,in The value is 395V, according to the formula. The estimated bus voltage drop at the moment the stacker crane is connected is calculated. The calculation results show that if the 220A current is allowed to be directly applied, the bus voltage value after deducting the estimated bus voltage drop will drop to 340V, which is lower than the preset minimum operating voltage threshold. ,in The value is 360V. Based on this, the load access control unit determines that the current physical state of the power supply circuit does not support the direct start of the high-impact load, and outputs an adjustment command to drive the frequency converter of the stacker crane to execute a soft start strategy, limiting the expected current increment during startup to within 100A. This avoids transient voltage drops on the bus due to impedance drift and prevents the PLC controller connected to the same bus from unexpectedly resetting due to voltage drop below the undervoltage lockout threshold.

[0033] Example 2: This example constructs a power distribution system verification platform based on hardware-in-the-loop (HIL) technology to quantitatively evaluate the voltage stability maintenance capability and impedance inversion accuracy of the proposed dynamic power load distribution system under non-ideal line conditions. The test platform consists of a programmable AC power supply (for simulating the characteristics of the main transformer and the upstream power grid), a set of adjustable impedance simulation networks (for physically reproducing the dynamic drift of the contact resistance of the sliding contact line), and multiple electronic load boxes with variable load characteristics (for simulating the power behavior of stacker cranes, conveyor rollers, and AGV charging piles). The test data is acquired using an independent high-precision data logger with a voltage measurement accuracy of 0.1V, a current measurement accuracy of 0.1A, and a time resolution of 100μs. In order to reproduce the electromagnetic environment of a real industrial site, a broadband noise generator is coupled in the test circuit to continuously inject random high-frequency harmonic noise accounting for 5% of the total power, so as to simulate the power grid pollution generated by the frequency converter drive equipment.

[0034] In the initialization phase of this experiment, the sampling frequency of the bus electrical parameter acquisition unit was locked at 10kHz. This parameter setting followed the engineering trade-off logic of Shannon's sampling theorem and transient characteristic capture capability: Given that the current step rise time of a typical inductive load in a logistics production line is usually between 5ms and 20ms, in order to accurately depict the wavefront characteristics of the current step and meet the time window requirements for impedance calculation without introducing excessive data processing redundancy, the sampling period needed to be set to at least one-fiftieth of the step rise time. Based on this logic, a sampling frequency of 10kHz (i.e., a 100μs period) can acquire 100 valid data points during a typical 10ms step, thus ensuring the accuracy of differential operations in the time domain. Value stability; a control group was established to verify the limitations of the existing technology in response to impedance drift conditions. In the control group setting, the equivalent series impedance of the power supply circuit was set to 0.25Ω by adjusting the impedance simulation network to simulate a high impedance state with severe wear of the sliding contact line. At this time, the no-load voltage of the common bus was maintained at 400V, and the background load was 30% of the rated capacity. When the electronic load box simulated a heavy-load device with a rated current of 200A and initiated a start request, the traditional static capacity management logic used in the control group only checked the remaining capacity of the transformer and determined that the current load rate was not exceeded. Therefore, it output a command to allow direct start. The waveform data recorded by the oscilloscope showed that within 50ms of the load connection, the bus voltage A violent drop occurred, with the lowest value momentarily reaching 345V, falling below the preset 360V undervoltage protection threshold. This caused the analog PLC control unit connected to the same busbar to trigger the power-off reset protection, resulting in an unexpected shutdown of the entire analog production line.

[0035] While maintaining the aforementioned high impedance (0.25Ω) and high noise background conditions, the prototype of this invention was started for testing. The system was in continuous operation. When the load of the simulated auxiliary motor generated a current step of 25A, the bus electrical parameter acquisition unit successfully locked the step signal using a differential filtering algorithm in the noise background and extracted the corresponding bus voltage change as 6.1V. The line impedance calculation unit, based on Ohm's law logic (6.1V divided by 25A), obtained the current equivalent impedance value of the system in real time. The calculated impedance is 0.244Ω, and the relative error between this calculated value and the physical set value of 0.25Ω is only 2.4%, proving the stability of the impedance identification algorithm under strong noise interference. When the aforementioned 200A heavy-duty equipment initiates a startup request again, the load access control unit executes the voltage stability judgment logic. Based on the latest calculated impedance value of 0.244Ω and the current bus voltage of 398V, this unit calculates the estimated voltage drop to be 48.8V. The logic operation results show that the remaining voltage after deducting the estimated voltage drop will be as low as 349.2V, which does not meet the minimum operating voltage threshold of 360V. The system immediately rejected the direct closing command and instead output an adjustment command, driving the electronic load bank to execute the ramp soft-start mode, limiting the equivalent inrush current at startup to 80A. Actual test data showed that, under the control of the sample group of this invention, the minimum bus voltage during the connection of heavy-load equipment was stably maintained at 378V, always higher than the safety threshold of 360V, without triggering any undervoltage protection action. Further gradient stress testing showed that as the simulated impedance value gradually increased from 0.05Ω to 0.5Ω, the system of this invention exhibited clear linear response characteristics: when the impedance value was small, the system allowed large current loads to connect quickly; when the impedance value exceeded the critical point, the system automatically narrowed the access boundary and implemented derating or delay strategies.

[0036] Example 3: This example focuses on the specific execution flow and parameter quantification procedure of the power balance control unit in this invention when processing regenerative braking energy, ensuring the feasibility of the technical solution in a scenario of collaborative operation of multiple devices. In the power distribution circuit of a logistics production line containing 20 Automated Guided Vehicles (AGVs) with a rated power of 5kW and 5 heavy-duty stacker cranes with a rated power of 45kW, the system is in a dynamic operating state, and the bus electrical parameter acquisition unit monitors the instantaneous voltage value of the common bus in real time. The sampling frequency is set to 10kHz, and the line impedance calculation unit updates and outputs the system equivalent impedance value in real time according to the method described in the previous embodiment. The power balance control unit has a built-in trigger determination module based on the voltage rise rate, which calculates the bus voltage within a preset sliding time window. The slope of the change within the interval is dU / dt, where Set to 20ms, when detected Exceeding the preset standard operating voltage limit, such as 410V, and with dU / dt consistently exceeding the preset voltage ramp-up threshold. When the voltage is set to 50V / s, the system determines that the bus is receiving regenerative energy from one or more variable frequency drive devices performing deceleration and braking operations, and that this energy is not being fully absorbed, causing an abnormal rise in the bus voltage. At this time, the power balance control unit generates a power consumption demand signal, which includes the estimated redundant power value to be consumed at the current moment. Its calculation is based on the formula ,in This is the equivalent capacitance value of the common bus circuit, which is obtained through offline measurement during the system initialization phase. In this embodiment, it is set to 5000μF.

[0037] In response to the power consumption demand signal, the power balance control unit queries the list of heavy-load devices in standby mode in the same power distribution circuit. Based on a preset priority strategy, the system selects one device to start its power demand. closest The stacker crane is selected as the target device, and a priority start command is sent to it, which includes a specific start delay time parameter. Its value is set to 0ms. When the stacker crane responds to the command to start and begins to draw current from the bus, the power it consumes offsets the regenerative braking energy on the bus, thereby suppressing... A further increase, if calculated If the starting power is less than the minimum available load, the system sends a command containing derating starting parameters to the load, limiting its starting current and reducing its power consumption to the minimum available load. Match, if The power consumption is much greater than that of a single device. The system simultaneously sends start commands to multiple standby devices and uses timing synchronization control to ensure that the total power consumption covers the peak regenerative energy. Through this dynamic absorption mechanism based on real-time voltage slope monitoring and power matching, the system effectively converts regenerative braking energy into useful work, avoids overvoltage protection tripping, and improves energy utilization efficiency and system stability.

[0038] Example 4: This example aims to provide a method for determining the overvoltage consumption threshold. Standardized engineering calibration procedures were established to ensure that the system achieves optimal regenerative energy absorption in logistics production lines of different scales and types. On an offline test platform with adjustable load characteristics, the system simulated a set of variable frequency drive devices with different power levels and regenerative energy feedback characteristics. The standard operating point of the bus voltage was set to 400V, and the injected power of the simulated regenerative braking energy was gradually increased. Simultaneously, the rise rate of the bus voltage (dU / dt) and the final steady-state voltage value were recorded. Through multiple sets of comparative experiments, the time required for the bus voltage to reach the system overvoltage protection trip threshold (e.g., 420V) under different dU / dt conditions without intervention was recorded. Data analysis shows that… When dU / dt is below 30V / s, the bus's own capacitance and the base load are sufficient to naturally dissipate this energy without external intervention. However, when dU / dt exceeds 70V / s, the voltage rises extremely rapidly, leaving the system less than 10ms for response time, which can easily trigger protection tripping. Based on this, the correlation curve between voltage rise rate and safe response time is fitted using the least squares method. Combined with the inherent response delay of the system hardware (including detection, calculation, and command transmission time, totaling approximately 15ms), the critical voltage rise rate required for intervention control is determined to ensure that the system does not experience overvoltage tripping. Finally, 80% of this critical rate is selected as the standard overvoltage dissipation threshold for engineering applications. In this embodiment, it is calibrated to 50V / s to achieve the best balance between sensitivity and false alarm rate.

[0039] To address the initial value of the system's equivalent impedance, this embodiment establishes a pre-deployment calibration procedure to resolve parameter uncertainties arising from differences in wiring across different physical production lines. Before the system is initially powered on and before any controlled heavy-load equipment is connected, a standard test load box with precisely known impedance characteristics is used to perform pulse injection calibration. The test load box injects a standard current pulse with a duration of 20ms and an amplitude of 50A into the busbar under controlled conditions. The busbar electrical parameter acquisition unit simultaneously records the busbar voltage drop waveform during this pulse. Based on the acquired voltage drop amplitude and the known current pulse amplitude, the line impedance calculation unit calculates the static equivalent impedance reference value of the current power supply circuit. During a continuous 24-hour trial operation cycle, the system continuously monitors and records natural load fluctuations under normal production cycle time and the resulting changes in calculated impedance values. It then statistically derives the normal distribution characteristics of the impedance values, ultimately... The initial impedance parameter is set as the initial impedance parameter when the system starts up, and the statistically obtained impedance fluctuation range is used as the judgment benchmark for impedance abnormality alarm, thereby completing the personalized parameter adaptation and baseline construction for a specific physical production line.

[0040] Example 5: This example constructs a system for accurately measuring bus voltage changes. and current step change amplitude To eliminate nonlinear interference and background noise during transient electrical parameter extraction, a standardized engineering parameter calibration procedure was implemented. On a dynamic load test platform with controllable noise injection, a test load with precise current injection capability was configured, and the bus voltage was stabilized at 400V. The current step amplitude was gradually increased in preset steps, while the instantaneous response waveform of the bus voltage was recorded using a high-frequency oscilloscope. Waveform analysis showed that in the first 2ms of the current step, the change in bus voltage was dominated by the distributed inductance effect of the line, exhibiting nonlinear characteristics. The voltage change rate in this region did not conform to Ohm's law of the pure resistance model. To avoid the weakening of impedance inversion accuracy by this inductively dominated region, a parameter extraction algorithm based on a hysteresis sliding time window was implemented. The starting point of the effective sampling window was set 3ms after the current step trigger moment, and the arithmetic mean of the voltage data collected within this window was used as the steady-state voltage after the step. and compare it with the initial voltage before the step jump. By performing differential operations, an effective method is obtained that eliminates inductive disturbances. Meanwhile, regarding the amplitude of current step change To determine the validity of the signal, the system executes a statistical noise threshold calibration process. Under steady-state conditions of no-load or light-load conditions, the system continuously collects bus current data for 1 second, calculates its standard deviation σ, and sets the threshold for current step detection to 3σ. When the detected current change exceeds this threshold, the system recognizes it as a valid step event and triggers the subsequent impedance calculation logic, thereby effectively filtering out false triggers caused by background electromagnetic noise.

[0041] The line impedance calculation unit reads the load access control unit's instruction transmission log, executes active shielding logic based on timestamp comparison, and distinguishes between controlled load actions and uncontrolled load disturbances. Whenever the load access control unit issues a closing command to any controlled load, the line impedance calculation unit initiates its operation for a specified duration. The shielding time window, in this embodiment The timeframe is set to 300ms, and the value is determined based on the typical transient response time of the controlled motor from energization to current stabilization. During this window, the line impedance calculation unit suspends impedance inversion calculations for detected current steps, ignoring data fluctuations within the time period. When the bus electrical parameter acquisition unit detects a current step signal occurring outside the shielding time window and the signal amplitude meets the dead zone threshold requirement, the line impedance calculation unit determines it as being caused by uncontrolled background loads not included in the management system or physical fluctuations on the grid side. Based on this, it initiates the voltage change extraction and system equivalent impedance update process, logically avoiding impedance calculation errors caused by the controlled load startup process being misjudged as line disturbances. For the instantaneous impedance value obtained from the inversion of a single current step event... The line impedance calculation unit performs data cleaning and smoothing procedures based on physical boundary constraints; the system presets the impedance physical rationality range. In this embodiment, the range is set to 0.01Ω to 0.80Ω based on the cable material and the transformer short-circuit impedance parameters. If the calculated... If the data falls outside the range, the system determines that the current sampling is affected by strong electromagnetic interference, discards the data, and maintains the impedance value of the previous cycle unchanged; for data falling within the range, the system determines that the current sampling is affected by strong electromagnetic interference, discards the data, and maintains the impedance value of the previous cycle unchanged. The system employs a first-order lag filtering algorithm to generate the final equivalent impedance value used to determine the logic system. The update logic follows the formula β is the forgetting factor, which is set to 0.15 in this embodiment. The parameter setting enables the system's equivalent impedance value to follow the actual drift trend of the physical state of the power supply circuit, filtering out high-frequency oscillations caused by random errors in a single measurement.

[0042] Regarding the system equivalent impedance To address potential physical drift during long-term operation, this embodiment establishes an adaptive calibration mechanism that includes environmental compensation and aging trend analysis. Temperature sensors are deployed at key connection nodes of the busbar to collect real-time data on the line's operating temperature. The line impedance calculation unit integrates a temperature correction module, based on the formula... The impedance value calculated in real time is standardized and corrected, where α is the temperature coefficient of resistance of the conductor material. In addition to the reference temperature, the system maintains a 100-group first-in-first-out (FIFO) historical database to store the data obtained from the inversion of each valid step event. The system periodically executes a trend analysis algorithm to calculate the moving average of historical data. The system calculates the rate of change of impedance over time, dR / dt. When the absolute value of dR / dt exceeds the preset aging warning threshold, the aging warning threshold is determined by multiplying the reference impedance value of the power supply circuit by a scaling factor of 1.20. During the first 168 hours of initial power-on operation, the system automatically calculates the arithmetic mean of impedance values ​​in the historical impedance database and calibrates it as the reference impedance value. When the equivalent impedance value of the system obtained from 10 consecutive impedance inversions is higher than 120% of the reference impedance value, the system determines that the contact resistance has physically deteriorated and generates a deep calibration request. In addition, the temperature correction module standardizes and compensates the impedance sampling values ​​in environments ranging from 10℃ to 80℃ according to a resistance change rate of 0.0039 per degree Celsius, thereby ensuring the accuracy of the warning threshold determination under different seasons and environmental loads. The system automatically generates a deep calibration request to prompt maintenance personnel to perform contact resistance detection on the physical connection status of the power supply circuit, thereby ensuring the accuracy of the system's perception of the physical impedance characteristics of the power grid throughout its entire life cycle.

[0043] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the present invention can be implemented in other specific forms without departing from the spirit or essential characteristics of the present invention.

[0044] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention.

Claims

1. A dynamic power load distribution system for flexible logistics production lines in smart factories, characterized in that, include: The bus electrical parameter acquisition unit is physically connected to the common bus of the power distribution circuit. It is used to acquire the instantaneous value of the bus voltage and the instantaneous value of the total circuit current of the common bus in real time at a preset sampling frequency, and to detect the current step change caused by the start and stop of uncontrolled loads in the logistics production line. The line impedance calculation unit is connected to the bus electrical parameter acquisition unit. It is used to respond to the current step change, obtain the bus voltage change within the change time window, and update the system equivalent impedance value, which represents the physical connection state of the current power supply circuit, in real time based on the ratio of the bus voltage change to the current step change amplitude that caused the change. The load access control unit is connected to the line impedance calculation unit and multiple controlled load controllers on the logistics production line. When a power access request is received from any controlled load, the control unit executes voltage stability judgment logic: based on the latest system equivalent impedance value and the expected current increment requested by the controlled load, it calculates the estimated bus voltage drop at the time of the controlled load access; if the value of the current instantaneous bus voltage minus the estimated bus voltage drop is not lower than the preset minimum operating voltage threshold, it outputs a closing command to allow the controlled load to start; if it is lower than the minimum operating voltage threshold, it outputs an adjustment command to control the controlled load to perform power limiting or delayed start.

2. The power load dynamic distribution system for flexible logistics production lines in smart factories according to claim 1, characterized in that, The line impedance calculation unit also includes a disturbance amplitude filtering module, which compares the absolute value of the amplitude of the monitored current step change with a preset current change dead zone threshold. When the absolute value of the current step change is greater than the current change dead zone threshold, the line impedance calculation unit performs an update calculation of the system equivalent impedance value. The line impedance calculation unit uses a weighted average algorithm to process the instantaneous impedance value obtained in this calculation with the historically stored impedance value to generate the system equivalent impedance value used for this determination.

3. The power load dynamic distribution system for flexible logistics production lines in smart factories according to claim 1, characterized in that, The system also includes: a power balance control unit, connected to the common bus and a frequency converter with regenerative braking function; the power balance control unit is used to monitor the voltage rise rate of the common bus, and when it detects that the bus voltage caused by regenerative braking energy exceeds a preset overvoltage consumption threshold, it generates a priority start command for the heavy-load equipment in the same power distribution circuit that is in standby mode; the priority start command is used to control the heavy-load equipment to start during the regenerative braking energy feedback period, thereby suppressing the rise of bus voltage by consuming regenerative braking energy.

4. The power load dynamic distribution system for flexible logistics production lines in smart factories according to claim 1, characterized in that, The voltage stability determination logic executed by the load connection control unit follows the following inequality: ,in, The instantaneous value of the current voltage of the common bus is collected. Let be the real part of the system's equivalent impedance. The expected current increment requested by the controlled load. The minimum operating voltage threshold is preset; the load connection control unit only outputs a closing command when the above inequality is true.

5. The power load dynamic distribution system for flexible logistics production lines in smart factories according to claim 1, characterized in that, The load access control unit includes a power level matching module, which selects a target power level from a set of preset power levels based on the current voltage margin when the estimated bus voltage drop causes the calculated result to be lower than the minimum operating voltage threshold. This ensures that the estimated bus voltage recalculated based on the target power level meets the minimum operating voltage threshold, and the target power level is included in the adjustment command and sent to the controlled load controller.

6. The power load dynamic distribution system for flexible logistics production lines in smart factories according to claim 1, characterized in that, The bus electrical parameter acquisition unit also includes a current spectrum analysis module, which is used to perform spectrum transformation on the acquired instantaneous value of the total loop current and extract the current ripple amplitude of a specific frequency band. The load access control unit is used to compare the extracted current ripple amplitude with a preset abnormal characteristic threshold. If it exceeds the abnormal characteristic threshold, the calculation weight of the corresponding controlled load in the calculation of the estimated bus voltage drop is increased to increase the retention margin of voltage stability.

7. A dynamic power load distribution system for flexible logistics production lines in smart factories according to claim 1, characterized in that, The system adopts a multi-level control architecture. The load access control unit includes a main controller located on the transformer outgoing line side and several sub-controllers located on the branch bus side. The main controller is used to process the power access request of the main line based on the system equivalent impedance of the main line. The sub-controllers are used to process the power access request of the branch load based on the local system equivalent impedance of the branch circuit. The sub-controllers are configured to send a closing command to the controlled load connected to them only after receiving the permission signal from the main controller.

8. A dynamic power load distribution system for flexible logistics production lines in smart factories according to claim 1, characterized in that, The line impedance calculation unit is also used to maintain a historical impedance database, which stores time-impedance data records for different production line sections. The load access control unit is used to call the historical impedance data corresponding to the current time period in the historical impedance database as an estimated value during the quiet period when the current uncontrolled load does not operate, and to execute the voltage stability determination logic.

9. A dynamic power load distribution system for flexible logistics production lines in smart factories according to claim 1, characterized in that, The controlled load controller is used to start a delay timer after receiving an adjustment command that requires a delayed start. The duration of the delay timer is determined based on the sum of a preset base time and a random deviation value. The load access control unit is used to set different preset reference times according to the process type identifier of the controlled load, so that the preset reference time of high priority process equipment is less than the preset reference time of low priority auxiliary equipment.

10. A dynamic power load distribution system for flexible logistics production lines in smart factories according to claim 1, characterized in that, The bus electrical parameter acquisition unit, line impedance calculation unit, and load access control unit are integrated into an industrial power distribution control terminal. The industrial power distribution control terminal directly acquires the voltage and current signals of the common bus through a hard-wired interface and connects to the controlled load controller through an industrial fieldbus to transmit closing or regulating commands.

Images