Intelligent cloud-edge collaborative microgrid control system

Abstract

The present invention relates to the field of microgrid control technology, and discloses an intelligent cloud-edge collaborative microgrid control system. In a time period before a water pump contactor closing signal is detected, the rate of change of the zero-sequence voltage per unit time is measured at fixed time intervals; the presence of a zero-sequence cross-reverse jump is determined based on the rate of change, and the jump moment of the zero-sequence cross-reverse jump is recorded; a virtual reactance is generated based on the polarity of the rate of change of the zero-sequence cross-reverse jump, and the virtual reactance is injected into the DC bus through an inverter; the presence of a DC negative pulse delayed zero crossing is determined based on the bus current, and the negative pulse energy corresponding to the DC negative pulse delayed zero crossing is estimated; the negative pulse energy is used as a control quantity, combined with a preset phase shift angle, and the control quantity is fed back to the water pump motor according to a preset power curve; after the feedback continues for a preset feedback time, the zero-sequence voltage and the DC bus current are obtained, and when the zero-sequence voltage and the DC bus current return to the normal operating range, the normal control mode is returned.

Description

Technical Field

[0001] The present invention relates to the field of microgrid control technology, and more specifically, to an intelligent cloud-edge collaborative microgrid control system. Background Art

[0002] In modern greenhouse cultivation environments, a hybrid power supply architecture combining DC and AC in parallel is often used to meet the power demands of multiple loads. The low-voltage DC bus continuously supplies power to low-power loads such as LED lighting fixtures, environmental monitoring sensors, automation controllers, and ventilation fans, ensuring the light and air circulation required for plant growth. The three-phase AC bus primarily provides power to high-power loads such as water pump systems, refrigeration compressors, and dehumidification equipment, ranging in power from 5 to 20 kilowatts.

[0003] Because the two busbars are linked via an inverter and rectifier, sudden voltage or current changes on either side are reflected on the other. Common system link effects include momentary busbar voltage drops, sharp increases in harmonic content, and phase sequence imbalance, all of which can cause lamp flickering, unstable fan speeds, and malfunction of sensitive electronic components. In actual operation, once a water pump is started directly online, its starting current can instantly climb to six to eight times the rated current, causing a significant drop in the AC busbar voltage. This voltage is then fed back to the DC busbar through the inverter, causing noticeable flickering in the LED lamps on the DC side.

[0004] Traditionally, systems often rely on secondary droop control or fixed-threshold protection strategies to cope with such impacts. However, the secondary droop regulation response is usually more than 40 milliseconds, which is far behind the current peak change within one to two milliseconds after the pump starts. This causes common-mode voltage drift on the DC side, which not only falsely triggers the microgrid's overcurrent trip, but may also cause long-term damage to the equipment's insulation performance, increasing the risk of system operation and maintenance. Summary of the Invention

[0005] The present invention provides an intelligent cloud-edge collaborative microgrid control system, which solves the technical problems raised in the background technology.

[0006] The present invention provides an intelligent cloud-edge collaborative microgrid control system, comprising:

[0007] The data acquisition module is used to measure the rate of change of the zero-sequence voltage per unit time at fixed time intervals through the edge node in the period before the water pump contactor closing signal is detected;

[0008] The voltage monitoring module is used to analyze and process the rate of change based on the cloud platform to determine the presence of zero-sequence cross-reverse jumps and record the jump moments of the zero-sequence cross-reverse jumps;

[0009] The virtual reactance module is used to generate a virtual reactance according to the polarity of the change rate of the zero-sequence cross-reverse jump at the jump moment, and inject the virtual reactance into the DC bus through the inverter;

[0010] The energy estimation module is used to monitor the bus current of the DC bus within 2 to 6 milliseconds after the jump moment, and determine whether there is a DC negative pulse delay zero crossing based on the bus current. If so, it enters the energy feedback module and estimates the negative pulse energy corresponding to the DC negative pulse delay zero crossing; otherwise, it maintains the normal control mode;

[0011] The energy feedback module is used to use the negative pulse energy as the control quantity after confirming that the DC negative pulse delay passes through zero, and in combination with the preset phase shift angle, feed the control quantity back to the water pump motor according to the preset power curve;

[0012] A feedback termination module is used to obtain the zero-sequence voltage and DC bus current after the feedback continues for a preset feedback time, and return to the normal control mode when the zero-sequence voltage and DC bus current return to the normal operating range;

[0013] The conventional control mode refers to the control mode of the microgrid control system under normal operating conditions.

[0014] Furthermore, the rate of change of zero-sequence voltage per unit time includes:

[0015] Calculate the voltage difference of the zero-sequence voltage at adjacent moments;

[0016] Determine the ratio of the voltage difference to the fixed time interval;

[0017] The ratio is taken as the rate of change of zero-sequence voltage per unit time.

[0018] Furthermore, the change rate is analyzed and processed based on the cloud platform to determine the presence of a zero-sequence cross-reverse jump, and the jump moment of the zero-sequence cross-reverse jump is recorded, including:

[0019] Compare the absolute value of the rate of change of the zero-sequence voltage per unit time with a preset jump threshold;

[0020] If the absolute value is greater than or equal to the preset transition threshold, it is determined that a zero-sequence cross-inversion transition occurs.

[0021] Furthermore, a virtual reactance is generated according to the polarity of the change rate of the zero-sequence cross-reverse jump, and the virtual reactance is injected into the DC bus through the inverter, including:

[0022] Determine the polarity of the rate of change corresponding to the zero-sequence cross-deflection transition;

[0023] The polarity of the rate of change is taken as the positive or negative direction of the virtual reactance;

[0024] The virtual reactance amplitude is calculated according to the absolute value of the change rate corresponding to the zero-sequence cross-deflection jump and the preset proportional coefficient, and the virtual reactance is generated in combination with the positive and negative directions of the virtual reactance;

[0025] The virtual reactance is converted into a voltage reference of the inverter and injected into the DC bus through the inverter as a voltage reference at the trip moment.

[0026] Furthermore, determining whether there is a DC negative pulse delayed zero crossing based on the bus current includes:

[0027] Within 2 to 6 milliseconds after the zero-sequence cross-inverse jump, the bus current of the DC bus is collected at a fixed time interval, and the minimum bus current within 2 to 6 milliseconds is obtained;

[0028] Compare the minimum bus current with a preset negative pulse threshold;

[0029] If the minimum bus current is less than or equal to the preset negative pulse threshold, it is determined that a DC negative pulse delayed zero crossing occurs.

[0030] Furthermore, the negative pulse energy corresponding to the delayed zero crossing of the DC negative pulse is estimated, including:

[0031] After determining that a DC negative pulse delay crosses zero, the equivalent inductance of the DC bus and the minimum bus current are read;

[0032] Calculate the product of the equivalent inductance of the DC bus and the square of the minimum bus current, and take half of the product as the negative pulse energy.

[0033] Furthermore, the negative pulse energy is used as the control quantity, combined with the preset phase shift angle, and the control quantity is fed back to the water pump motor according to the preset power curve, including:

[0034] The target phase shift angle is calculated based on the mapping relationship between the negative pulse energy and the preset phase shift angle;

[0035] According to the target phase shift angle, a power reference value is obtained by querying the preset power curve;

[0036] The target phase shift angle is input into the bidirectional active transformer controller, and the bidirectional active transformer controller is driven by the power reference value to feed back energy to the water pump motor.

[0037] Furthermore, when the zero-sequence voltage and DC bus current return to the normal operating range, the control mode is returned to normal, including:

[0038] Collect zero-sequence voltage and DC bus current at fixed time intervals;

[0039] When the absolute value of the zero-sequence voltage is less than or equal to the first steady-state threshold, and the absolute value of the bus current is less than or equal to the second steady-state threshold, and this continues for 5 milliseconds, the system returns to the normal control mode and executes the following operations within the preset switching time period:

[0040] Linearly set the voltage reference of the inverter corresponding to the virtual reactance to zero;

[0041] The power reference value and phase shift angle of the bidirectional active transformer controller are linearly set to zero.

[0042] The beneficial effect of the present invention is that by constructing an intelligent cloud-edge collaborative microgrid control system, the linkage recognition and bidirectional closed-loop control of zero-sequence cross-reverse jump and DC negative pulse delayed zero crossing are realized. It can not only accurately identify and inject virtual reactance with matching polarity within milliseconds to suppress zero-sequence disturbance, but also quantitatively estimate the energy generated by the DC bus negative pulse and feed it back to the water pump motor to form re-acceleration, realizing the full process control from abnormal triggering → energy tracking → collaborative compensation → soft exit, effectively improving the steady-state recovery capability and energy utilization efficiency of the microgrid system under high-power load impact, and breaking through the technical bottleneck of traditional control systems for heterogeneous transient weak correlation, response lag and processing fragmentation. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] Figure 1 It is a module diagram of the intelligent cloud-edge collaborative microgrid control system of the present invention. DETAILED DESCRIPTION

[0044] The subject matter described herein will now be discussed with reference to exemplary embodiments. It should be understood that these embodiments are discussed solely to enable those skilled in the art to better understand and implement the subject matter described herein, and that the functions and arrangements of the elements discussed may be varied without departing from the scope of this specification. Various examples may omit, substitute, or add various processes or components as needed. In addition, features described with respect to some examples may also be combined in other examples.

[0045] like Figure 1 As shown in the figure, the intelligent cloud-edge collaborative microgrid control system includes:

[0046] The data acquisition module is used to measure the rate of change of the zero-sequence voltage per unit time at fixed time intervals through the edge node in the period before the water pump contactor closing signal is detected;

[0047] The voltage monitoring module is used to analyze and process the rate of change based on the cloud platform to determine the presence of zero-sequence cross-reverse jumps and record the jump moments of the zero-sequence cross-reverse jumps;

[0048] The virtual reactance module is used to generate a virtual reactance according to the polarity of the change rate of the zero-sequence cross-reverse jump at the jump moment, and inject the virtual reactance into the DC bus through the inverter;

[0049] The energy estimation module is used to monitor the bus current of the DC bus within 2 to 6 milliseconds after the jump moment, and determine whether there is a DC negative pulse delay zero crossing based on the bus current. If so, it enters the energy feedback module and estimates the negative pulse energy corresponding to the DC negative pulse delay zero crossing; otherwise, it maintains the normal control mode;

[0050] The energy feedback module is used to use the negative pulse energy as the control quantity after confirming that the DC negative pulse delay passes through zero, and in combination with the preset phase shift angle, feed the control quantity back to the water pump motor according to the preset power curve;

[0051] A feedback termination module is used to obtain the zero-sequence voltage and DC bus current after the feedback continues for a preset feedback time, and return to the normal control mode when the zero-sequence voltage and DC bus current return to the normal operating range;

[0052] The conventional control mode refers to the control mode of the microgrid control system under normal operating conditions.

[0053] In one embodiment of the present invention, the rate of change of the zero-sequence voltage per unit time includes:

[0054] Calculate the voltage difference of the zero-sequence voltage at adjacent moments, thereby extracting the instantaneous voltage change amplitude between two consecutive sampling points;

[0055] Determine the ratio of the voltage difference to the fixed time interval, and normalize the original voltage difference to a unified time base to obtain a standardized change;

[0056] The ratio is taken as the rate of change of the zero-sequence voltage per unit time, so that the normalized result can be directly output as a rate feature.

[0057] Specifically, the voltage difference of the zero-sequence voltage at adjacent moments refers to the difference obtained by subtracting the zero-sequence voltage values ​​at two consecutive sampling moments, which is used to reflect the instantaneous voltage change amplitude.

[0058] The ratio of the voltage difference to the fixed time interval is used to quantize the ratio of the voltage difference to the uniform sampling interval and to normalize the difference component to the time derivative.

[0059] The rate of change of zero-sequence voltage per unit time represents the rate at which the zero-sequence voltage changes over time, expressed as the ratio of the voltage difference to a fixed time interval, and is used for subsequent abnormality determination.

[0060] In one embodiment of the present invention, the change rate is analyzed and processed based on the cloud platform to determine whether there is a zero-sequence cross-reverse jump, and the jump time of the zero-sequence cross-reverse jump is recorded, including:

[0061] Compare the absolute value of the rate of change of the zero-sequence voltage per unit time with a preset jump threshold;

[0062] If the absolute value is greater than or equal to the preset transition threshold, it is determined that a zero-sequence cross-inversion transition occurs.

[0063] The absolute value of the rate of change of the zero-sequence voltage per unit time represents a positive number obtained by taking the absolute value of the rate of change of the zero-sequence voltage per unit time, and is used to quantify the magnitude of the transient change of the voltage.

[0064] The preset jump threshold value represents a preset change rate threshold value for determining a zero-sequence cross-reverse jump, and is used to distinguish normal fluctuations from zero-sequence cross-reverse jump events.

[0065] It should be noted that a zero-sequence cross-reverse trip physically manifests as a short, large reverse swing in the zero-sequence voltage, corresponding to a sudden increase in the absolute value of the rate of change per unit time. By comparing this abnormal sudden change with a preset trip threshold, it is possible to distinguish this abnormal change from regular, small fluctuations, thereby reliably detecting cross-reverse trip events. By comparing the absolute value of the zero-sequence voltage rate of change per unit time with the preset trip threshold, it is possible to determine whether the current fluctuation is sufficiently severe, thus providing a basis for detecting zero-sequence cross-reverse trip events.

[0066] In one embodiment of the present invention, a virtual reactance is generated according to the polarity of the rate of change of the zero-sequence cross-reverse jump, and the virtual reactance is injected into the DC bus through the inverter, including:

[0067] Determine the polarity of the rate of change corresponding to the zero-sequence cross-deflection transition;

[0068] The polarity of the rate of change is taken as the positive or negative direction of the virtual reactance;

[0069] The virtual reactance amplitude is calculated according to the absolute value of the change rate corresponding to the zero-sequence cross-deflection jump and the preset proportional coefficient, and the virtual reactance is generated in combination with the positive and negative directions of the virtual reactance;

[0070] The virtual reactance is converted into a voltage reference of the inverter and injected into the DC bus through the inverter as a voltage reference at the trip moment.

[0071] It should be noted that the polarity of the rate of change corresponding to the zero-sequence cross-reverse jump indicates the positive or negative sign of the rate of change per unit time when the zero-sequence voltage undergoes a cross-reverse jump, and is used to characterize the directionality of the voltage mutation. The virtual reactance represents the equivalent reactance value generated based on the characteristics of the zero-sequence cross-reverse jump, which is used to inject the DC bus through the inverter to dynamically adjust the system impedance. The preset proportional coefficient represents the empirical coefficient multiplied by the absolute value of the rate of change when calculating the virtual reactance amplitude, which is used to map the magnitude of the rate of change to the virtual reactance value. The voltage reference of the inverter represents the voltage command signal after converting the virtual reactance value.

[0072] Specifically, the direction of the voltage mutation is determined by reading the sign of the rate of change to generate an impedance compensation signal in the opposite direction. The polarity of the rate of change is directly mapped to the sign attribute of the virtual reactance to ensure that the direction of the injected reactance is opposite to the disturbance direction. The reactance amplitude is obtained by multiplying the absolute value of the quantized rate of change by a preset proportional coefficient. This is then combined with the sign information to generate the final virtual reactance for precise compensation. The virtual reactance value is converted into a voltage command executable by the inverter and injected at the precise moment of the jump to ensure the timeliness and effectiveness of the compensation action.

[0073] Through direction judgment → value calculation → sign assignment → timing injection, accurate identification and dynamic compensation of zero-sequence cross-reverse transition are achieved.

[0074] In one embodiment of the present invention, determining the presence of a DC negative pulse delayed zero crossing based on the bus current includes:

[0075] Within 2 to 6 milliseconds after the zero-sequence cross-inverse jump, the bus current of the DC bus is collected at a fixed time interval, and the minimum bus current within 2 to 6 milliseconds is obtained;

[0076] Compare the minimum bus current with a preset negative pulse threshold;

[0077] If the minimum bus current is less than or equal to the preset negative pulse threshold, it is determined that a DC negative pulse delayed zero crossing occurs.

[0078] The preset negative pulse threshold is the preset current threshold used to determine whether the DC bus current has undergone a negative zero-crossing pulse. It is used to distinguish normal current fluctuations from delayed negative zero-crossing pulses. A delayed DC negative zero-crossing pulse indicates a transient phenomenon in which a negative pulse appears in the DC bus current after a zero-sequence cross-deflection transition and remains at the zero-crossing point. This phenomenon is used to identify energy backflow events.

[0079] It's important to note that the energy return generated by the DC negative pulse doesn't occur immediately after the zero-sequence transition. Instead, it undergoes a transient process involving the establishment of the motor's stator winding and flux linkage, as well as the switching on and off of the inverter bridge arm. These two processes combine to ensure that significant negative pulses are not observed on the DC bus until approximately 2 milliseconds after the transition. The resonant frequency of the DC bus's inductance and capacitance typically ranges from several hundred hertz to kilohertz, corresponding to a voltage or current buffer period of 1 to 10 milliseconds. A period of approximately 6 milliseconds is sufficient to cover a full half-cycle of the main oscillation. After this point, the pulse energy has significantly decayed, and continued monitoring will introduce more post-oscillation noise rather than the main pulse signature. Selecting a period of 2 to 6 milliseconds avoids the startup noise of current spikes between 0 and 2 milliseconds, while also terminating detection quickly after 6 milliseconds to avoid capturing low-frequency drift or external interference unrelated to the main negative pulse.

[0080] In one embodiment of the present invention, estimating the negative pulse energy corresponding to the delayed zero crossing of a DC negative pulse includes:

[0081] After determining that a DC negative pulse delay crosses zero, the equivalent inductance of the DC bus and the minimum bus current are read;

[0082] Calculate the product of the equivalent inductance of the DC bus and the square of the minimum bus current, and take half of the product as the negative pulse energy.

[0083] Negative pulse energy refers to the electromagnetic energy stored in the pulse current when a negative pulse current appears in the DC bus.

[0084] It should be noted that the equivalent inductance of the DC bus refers to the parameter obtained from the system configuration after the DC negative pulse delay zero crossing is determined to have occurred, indicating that the DC bus is equivalent to a single inductor element. It is used to describe the energy storage and impedance characteristics of the bus to current changes.

[0085] Based on the inductive energy storage principle, half of the product of the equivalent inductance of the DC bus and the square of the minimum bus current is estimated as the negative pulse energy.

[0086] In one embodiment of the present invention, negative pulse energy is used as a control variable, combined with a preset phase shift angle, and the control variable is fed back to the water pump motor according to a preset power curve, including:

[0087] The target phase shift angle is calculated based on the mapping relationship between the negative pulse energy and the preset phase shift angle;

[0088] According to the target phase shift angle, a power reference value is obtained by querying the preset power curve;

[0089] The target phase shift angle is input into the bidirectional active transformer controller, and the bidirectional active transformer controller is driven by the power reference value to feed back energy to the water pump motor.

[0090] It should be noted that the target phase shift angle is calculated based on the mapping relationship between the negative pulse energy and the preset phase shift angle, as follows:

[0091]

[0092] in, represents the target phase shift angle, Indicates the preset phase shift angle, represents the negative pulse energy, Indicates the maximum recoverable negative pulse energy calibrated by the bidirectional active transformer controller.

[0093] The preset power curve represents a set of corresponding relationship curves between power reference values ​​and phase shift angles that are preset and stored in the controller, and is used to convert the required phase shift angle into actual output power.

[0094] The bidirectional active transformer controller is a control unit for the inverter and rectifier devices that bidirectionally injects or absorbs energy according to control signals, and is used to realize energy feedback to the water pump motor.

[0095] Through energy → angle mapping → power query → bidirectional injection, the DC negative pulse energy is efficiently converted into controllable feedback power for the water pump motor, thereby accelerating the water pump startup and improving the overall energy utilization efficiency of the system while compensating for voltage disturbances.

[0096] In one embodiment of the present invention, when the zero-sequence voltage and the DC bus current return to the normal operating range, returning to the normal control mode includes:

[0097] Collect zero-sequence voltage and DC bus current at fixed time intervals;

[0098] When the absolute value of the zero-sequence voltage is less than or equal to the first steady-state threshold, and the absolute value of the bus current is less than or equal to the second steady-state threshold, and this continues for 5 milliseconds, the system returns to the normal control mode and executes the following operations within the preset switching time period:

[0099] Linearly set the voltage reference of the inverter corresponding to the virtual reactance to zero;

[0100] The power reference value and phase shift angle of the bidirectional active transformer controller are linearly set to zero.

[0101] When the absolute value of the zero-sequence voltage is less than or equal to the first steady-state threshold, it means that the absolute value of the zero-sequence voltage does not exceed the first steady-state limit value set in advance, indicating that the zero-sequence disturbance has decayed to an acceptable range.

[0102] When the absolute value of the bus current is less than or equal to the second steady-state threshold, it means that the absolute value of the DC bus current does not exceed the preset second steady-state limit, indicating that the DC side pulse has been eliminated to an acceptable range.

[0103] Through condition monitoring → steady-state judgment → linear cancellation → mode switching, it is ensured that after the zero-sequence disturbance and DC pulse return to normal, the system can smoothly and reliably return to the normal control mode.

[0104] In one embodiment of the present invention, a greenhouse microgrid consists of a photovoltaic array, energy storage batteries, an active transformer, and a DC / AC hybrid busbar. This system must support the simultaneous operation of LED lighting, ventilation fans, and a 20-kilowatt water pump. To prevent bus voltage drops and subsequent harmonic disturbances caused by high current surges during direct pump startup, a multi-module cloud-edge collaborative control process is employed to predict, identify, compensate, and provide energy feedback for abnormal events within milliseconds, allowing for a smooth return to normal control upon system recovery.

[0105] The hardware and environment configuration are as follows:

[0106] Main control unit: adopts high-performance digital signal processor with sampling bandwidth of more than 50 kHz;

[0107] Measurement channel: A zero-sequence voltage sensor and a DC bus current sensor are deployed separately and connected to a digital signal processor through an isolation amplifier;

[0108] Actuator: The inverter is responsible for injecting virtual reactance, and the active transformer is responsible for energy feedback;

[0109] Network structure: The local DSP collaborates with the edge server, and the edge side can adjust the local control algorithm online based on the large model.

[0110] The detailed control process is as follows:

[0111] S1, Danger Window Preset: When the controller detects the pump contactor issuing a closing command, it starts high-speed sampling mode within a pre-set time range, continuously sampling the zero-sequence voltage and DC bus current. This window is set slightly before the closing moment to ensure that the initial precursor signals of the startup are captured.

[0112] S2, Zero-sequence cross-over jump identification: Within the danger window, the absolute value of the voltage change rate of adjacent sampling points is calculated in real time and compared with a pre-set transition threshold. If the rate reaches or exceeds the threshold, the controller immediately identifies a zero-sequence voltage cross-over jump, records the instantaneous timestamp, and saves the change direction information for subsequent compensation.

[0113] S3, dynamic virtual impedance injection: Once a zero-sequence reverse transition is confirmed, the system immediately generates a sign-correlated virtual reactance based on the transition direction and injects it into the DC bus through the inverter. This injection action, triggered at the transition moment, instantly reshapes the three-phase equivalent impedance to a symmetrical state, thereby quickly suppressing subsequent zero-sequence reverse peaks.

[0114] S4, DC negative pulse delayed zero crossing determination: For a specified period of time after the trip event (approximately two to six milliseconds), the controller continuously records the DC bus current in high-speed sampling mode and extracts the lowest current value occurring during this period. If this lowest current value reaches the preset negative pulse threshold, it is determined that the DC bus has experienced a negative pulse delayed zero crossing, and the time of occurrence is recorded.

[0115] S5, Negative Pulse Energy Estimation and Feedback: After determining the negative pulse energy, the system reads the busbar equivalent inductance and minimum current peak value. Using the principle of inductive energy storage, it estimates the energy carried by the negative pulse and uses this energy as the sole input for feedback control. Based on a preset mapping relationship, the controller first calculates the most appropriate phase shift angle, then retrieves the corresponding power reference value from the power mapping table. Finally, the phase shift angle and power command are sent to the active transformer controller to precisely inject the pulse energy into the water pump motor, enabling the motor to obtain re-acceleration torque while suppressing DC bus voltage tailing.

[0116] S6, Recovery and Adaptive Optimization: After the regenerative action is complete, the controller continuously monitors the zero-sequence voltage and DC bus current. A smooth exit process is triggered only when both fall back below the preset steady-state thresholds for a sustained period of several milliseconds. During this process, the inverter voltage command corresponding to the virtual reactance and the power and phase shift angle of the active transformer are linearly reset to zero, ensuring a smooth transition without generating new spikes. After the exit action is complete, the large-scale online learning module automatically optimizes the jump judgment threshold, negative pulse threshold, and reactance proportional coefficient based on the zero-sequence and DC current error data of this event, providing better control parameters for future starting events.

[0117] The beneficial effects of the present invention are as follows:

[0118] The combined zero-sequence cross-deflection event and DC negative pulse event were identified and compensated in dual domains within approximately seven milliseconds, effectively suppressing bus voltage and current spikes. Pulse energy was successfully converted into pump re-acceleration torque through feedback control, significantly reducing the need for auxiliary external energy storage devices. A soft zero return strategy during system exit prevented secondary transient shocks, ensuring the continuity and longevity of subsequent equipment operations.

[0119] The above describes the embodiments of this embodiment, but this embodiment is not limited to the above specific implementation methods. The above specific implementation methods are merely illustrative and not restrictive. Ordinary technicians in this field can also make many forms based on the inspiration of this embodiment, all of which are protected by this embodiment.

Claims

1. Intelligent cloud-edge collaborative microgrid control system, characterized by: include: The data acquisition module is used to measure the rate of change of the zero-sequence voltage per unit time at fixed time intervals through the edge node in the period before the water pump contactor closing signal is detected; The voltage monitoring module is used to analyze and process the rate of change based on the cloud platform to determine the presence of zero-sequence cross-reverse jumps and record the jump moments of the zero-sequence cross-reverse jumps; The virtual reactance module is used to generate a virtual reactance according to the polarity of the change rate of the zero-sequence cross-reverse jump at the jump moment, and inject the virtual reactance into the DC bus through the inverter; The energy estimation module is used to monitor the bus current of the DC bus within 2 to 6 milliseconds after the jump moment, and determine whether there is a DC negative pulse delay zero crossing based on the bus current. If so, it enters the energy feedback module and estimates the negative pulse energy corresponding to the DC negative pulse delay zero crossing; otherwise, it maintains the normal control mode; The energy feedback module is used to use the negative pulse energy as the control quantity after confirming that the DC negative pulse delay passes through zero, and in combination with the preset phase shift angle, feed the control quantity back to the water pump motor according to the preset power curve; A feedback termination module is used to obtain the zero-sequence voltage and DC bus current after the feedback continues for a preset feedback time, and return to the normal control mode when the zero-sequence voltage and DC bus current return to the normal operating range; The conventional control mode refers to the control mode of the microgrid control system under normal operating conditions.

2. The intelligent cloud-edge collaborative microgrid control system according to claim 1 is characterized in that: The rate of change of zero-sequence voltage per unit time includes: Calculate the voltage difference of the zero-sequence voltage at adjacent moments; Determine the ratio of the voltage difference to the fixed time interval; The ratio is taken as the rate of change of zero-sequence voltage per unit time.

3. The intelligent cloud-edge collaborative microgrid control system according to claim 2 is characterized in that: The rate of change is analyzed and processed based on the cloud platform to determine the presence of zero-sequence cross-reverse jumps and record the jump moments of the zero-sequence cross-reverse jumps, including: Compare the absolute value of the rate of change of the zero-sequence voltage per unit time with a preset jump threshold; If the absolute value is greater than or equal to the preset transition threshold, it is determined that a zero-sequence cross-inversion transition occurs.

4. The intelligent cloud-edge collaborative microgrid control system according to claim 3 is characterized in that: A virtual reactance is generated according to the polarity of the change rate of the zero-sequence cross-reverse jump, and is injected into the DC bus through the inverter, including: Determine the polarity of the rate of change corresponding to the zero-sequence cross-deflection transition; The polarity of the rate of change is taken as the positive or negative direction of the virtual reactance; The virtual reactance amplitude is calculated according to the absolute value of the change rate corresponding to the zero-sequence cross-deflection jump and the preset proportional coefficient, and the virtual reactance is generated in combination with the positive and negative directions of the virtual reactance; The virtual reactance is converted into a voltage reference of the inverter and injected into the DC bus through the inverter as a voltage reference at the trip moment.

5. The intelligent cloud-edge collaborative microgrid control system according to claim 4 is characterized in that: Determine the presence of DC negative pulse delayed zero crossing based on bus current, including: Within 2 to 6 milliseconds after the zero-sequence cross-inverse jump, the bus current of the DC bus is collected at a fixed time interval, and the minimum bus current within 2 to 6 milliseconds is obtained; Compare the minimum bus current with a preset negative pulse threshold; If the minimum bus current is less than or equal to the preset negative pulse threshold, it is determined that a DC negative pulse delayed zero crossing occurs.

6. The intelligent cloud-edge collaborative microgrid control system according to claim 5 is characterized in that: Estimating the negative pulse energy corresponding to the delayed zero crossing of the DC negative pulse includes: After determining that a DC negative pulse delay crosses zero, the equivalent inductance of the DC bus and the minimum bus current are read; Calculate the product of the equivalent inductance of the DC bus and the square of the minimum bus current, and take half of the product as the negative pulse energy.

7. The intelligent cloud-edge collaborative microgrid control system according to claim 6 is characterized in that: Using negative pulse energy as the control variable, combined with the preset phase shift angle, the control variable is fed back to the water pump motor according to the preset power curve, including: The target phase shift angle is calculated based on the mapping relationship between the negative pulse energy and the preset phase shift angle; According to the target phase shift angle, a power reference value is obtained by querying the preset power curve; The target phase shift angle is input into the bidirectional active transformer controller, and the bidirectional active transformer controller is driven by the power reference value to feed back energy to the water pump motor.

8. The intelligent cloud-edge collaborative microgrid control system according to claim 7 is characterized in that: When the zero-sequence voltage and DC bus current return to the normal operating range, the system returns to normal control mode, including: Collect zero-sequence voltage and DC bus current at fixed time intervals; When the absolute value of the zero-sequence voltage is less than or equal to the first steady-state threshold, and the absolute value of the bus current is less than or equal to the second steady-state threshold, and this continues for 5 milliseconds, the system returns to the normal control mode and executes the following operations within the preset switching time period: Linearly set the voltage reference of the inverter corresponding to the virtual reactance to zero; The power reference value and phase shift angle of the bidirectional active transformer controller are linearly set to zero.

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