Large mobile storage and charging power supply vehicle emergency power supply system

Abstract

The application belongs to the technical field of emergency power supply of power supply vehicles, and particularly discloses a large mobile storage and charging power supply vehicle emergency power supply system, which comprises a vehicle-mounted energy storage unit, a power conversion unit, a PWM signal generation unit, a load monitoring unit and a control unit. The control unit determines the grid-connected or off-grid mode by collecting the grid on-off state, the total load power and calculating the power change rate: when grid-connected, the instantaneous voltage value is monitored, and after triggering the lockout cooperative control, the power supply process is executed; when off-grid, the load impact component is identified and verified, if not passed or the power is over limit, the load is graded and removed, and the cycle verification is performed, if passed, the timing graded loading control is executed according to the adjustment stage number determined according to the load type and proportion. The grid-connected and off-grid modes can be flexibly selected according to the actual working condition, the single power supply mode is changed, the adaptability to different scenes is improved, the real uninterrupted power supply demand is met, and the impact load is accurately controlled.

Description

Technical Field

[0001] This invention belongs to the field of emergency power supply control technology for power supply vehicles, and more specifically, relates to an emergency power supply system for a large mobile energy storage and charging power supply vehicle. Background Technology

[0002] Large mobile energy storage and charging vehicles perfectly combine large-capacity energy storage technology, advanced power electronics technology, and mobile platforms. With their characteristics of speed, flexibility, cleanliness, intelligence, and high power, they have become an important tool for responding to emergencies, ensuring power supply, and enhancing grid resilience. They are playing an increasingly important role in urban management, energy transition, and public safety.

[0003] Prior art 1, as disclosed in Chinese invention patent application No. 202211744215.5, is an uninterrupted power supply system and method based on an emergency energy storage vehicle. This method utilizes an energy management vehicle to coordinate multiple battery vehicles into a power supply cluster. The power conversion module within the energy management vehicle enables rapid switching and voltage stabilization between the battery vehicles. While a single battery vehicle supplies power to the load, the remaining vehicles can disconnect from the system for charging. This solves the noise pollution and emission problems caused by continuous operation of traditional diesel power vehicles, while simultaneously achieving zero interruption of load power supply during online battery replacement, significantly extending the continuous power supply capability of mobile energy storage.

[0004] Prior art 2, such as Chinese invention patent application number 202111205327.9, discloses an emergency power vehicle based on hydrogen energy power supply and its power supply control method. This method integrates a hydrogen energy power generation device and an energy storage battery into the mobile vehicle. The hydrogen energy unit serves as the main power source, providing basic power, while the energy storage battery operates in parallel to balance hydrogen energy output fluctuations in real time and supplement power supply. Through the coordinated regulation of both, the inverter can output a stable 380V AC power, overcoming the voltage instability defect of a single hydrogen energy power supply and improving the power supply reliability of the emergency power vehicle under complex operating conditions.

[0005] The existing technical solutions mentioned above still have the following problems in operation and maintenance under emergency power supply scenarios: 1. Solution 1 only achieves seamless power switching at the physical level through multi-battery wheel rotation, and Solution 2 focuses on the power balance output of hydrogen energy and batteries. Neither of them has established a power supply mode decision mechanism based on grid status and load characteristics, resulting in a single power supply mode and a lack of adaptive switching capability under working conditions.

[0006] 2. Both uninterrupted power supply solutions are limited to a single mode. Solution 1's battery wheel replacement is a power replacement within the same off-grid mode and cannot achieve dynamic switching between grid-connected and off-grid modes. Solution 2's battery collaboration only optimizes output stability in off-grid mode and does not solve the voltage sag problem during mode switching. Therefore, they cannot meet the true uninterrupted power supply requirements.

[0007] 3. Both schemes are insufficient in handling load compatibility in off-grid mode. Scheme 1 does not handle impulsive loads in a graded manner, which can easily trigger overload protection. Scheme 2 does not verify the matching between load characteristics and the transient response capability of the power supply vehicle, such as the harmonic tolerance of nonlinear loads, which makes it impossible to guarantee stable support for complex loads when powering off-grid. In particular, it lacks an active management strategy for impulsive components. Summary of the Invention

[0008] In view of this, in order to solve the above problems, an emergency power supply system for a large mobile energy storage and charging power vehicle is proposed.

[0009] The objective of this invention can be achieved through the following technical solution: This invention provides an emergency power supply system for a large mobile energy storage and charging power vehicle, including an on-board energy storage unit, a power conversion unit, a PWM signal generation unit, a load monitoring unit, and a control unit. The control unit is characterized in that it collects the on / off status of the power grid, obtains the total power of the load side through the load monitoring unit, and calculates the power change rate based on the differential circuit.

[0010] The power supply mode is determined based on the on / off state and the power change rate, and the power supply mode includes grid-connected power supply and off-grid power supply.

[0011] If grid-connected power supply is triggered, the instantaneous values ​​of the power vehicle output voltage and the grid-side voltage are continuously monitored. After triggering the interlocking and coordinated control, the grid-connected power supply process is executed.

[0012] If off-grid power supply is triggered, the load impact component is identified by the current sensor, and it is verified whether the peak value of the impact exceeds the amplitude threshold and whether the duration exceeds the time threshold.

[0013] If the verification fails or the total power exceeds the limit, the load branch is cut off step by step starting from the lowest priority load according to the preset load classification library, and the impulse verification and power check are re-executed. This process is repeated until the verification passes and the total power does not exceed the limit.

[0014] If the verification passes and the total power does not exceed the limit, the off-grid power supply process is matched, and the timing-based hierarchical loading control is executed according to the number of adjustment stages determined based on the load type and the proportion of total load.

[0015] Compared with the prior art, the beneficial effects of the present invention are as follows: (1) The present invention determines the power supply mode by collecting the on / off state of the power grid side, combining the total power of the load side and the power change rate obtained by the differential circuit, and can flexibly choose between grid connection and off-grid according to the actual working conditions, which changes the situation of single power supply mode and improves the adaptability to different scenarios.

[0016] (2) When the grid-connected power supply is triggered, the present invention continuously monitors the instantaneous values ​​of the output voltage of the power vehicle and the voltage on the grid side and performs interlocking coordinated control. During the mode switching process, it can effectively suppress voltage dips, realize a smooth transition between grid-connected and off-grid modes, and meet the requirements of true uninterrupted power supply.

[0017] (3) When the present invention is powered off-grid, it identifies the load impact component by a current sensor, verifies the impact peak value and duration, and cuts off some load branches according to a preset priority and re-verifies the case where the conditions are not met or the total power exceeds the limit, thereby accurately controlling the impact load, avoiding false triggering of overload protection, and improving the tolerance to complex loads.

[0018] (4) When the off-grid power supply verification is passed and the total power is compliant, the present invention determines the number of adjustment stages and executes the timing-based hierarchical loading control according to the load type and the total load ratio. It can reasonably allocate power supply resources according to the load characteristics, effectively optimize the output stability when the off-grid power supply is used, ensure stable support for various loads, and enhance the reliability of emergency power supply. Attached Figure Description

[0019] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0020] Figure 1 This is a schematic diagram of the overall structure of the present invention.

[0021] Figure 2 This is a schematic diagram of the configuration process of the control unit of the present invention.

[0022] Figure 3 A schematic diagram illustrating the specific steps involved in grid-connected power supply.

[0023] Figure 4 This is a schematic diagram illustrating the specific process steps of the timing-based hierarchical loading control of the present invention. Detailed Implementation

[0024] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0025] Please see Figure 1As shown, the present invention provides an emergency power supply system for a large mobile energy storage and charging power vehicle, including an on-board energy storage unit, a power conversion unit, a PWM signal generation unit, a load monitoring unit, and a control unit.

[0026] In the above-described configuration, the output of the on-board energy storage unit is connected to the DC side of the power conversion unit. The PWM signal generation unit is coupled to the power conversion unit. The PWM signal generation unit generates corresponding PWM signals according to control commands. These signals are input to the switching device drive circuit in the power conversion unit to control the on / off state of the switching devices. The control unit is connected to the PWM signal generation unit. Based on the system's operating status and control strategy, the control unit sends commands such as target power signals to the PWM signal generation unit. The PWM signal generation unit generates PWM signals with corresponding duty cycles and frequencies according to these commands. The load monitoring unit collects real-time data on load parameters such as current, voltage, and power through sensors, such as current and voltage sensors, and then transmits this information to the control unit. Simultaneously, the load monitoring unit can indirectly monitor the output of the power conversion unit. By monitoring the load's operating status and electrical parameters, it is possible to determine whether the electrical energy output by the power conversion unit meets the load's requirements.

[0027] Please see Figure 2 As shown, the control unit includes: S1, collecting the on / off status of the power grid, obtaining the total power of the load side through the load monitoring unit, and calculating the power change rate based on the differential circuit.

[0028] Specifically, the rate of change of power can be directly calculated by differentiating the power signal using a differentiating circuit.

[0029] S2. Determine the power supply mode based on the on / off state and power change rate, wherein the power supply mode includes grid-connected power supply and off-grid power supply.

[0030] S3. If grid-connected power supply is triggered, continuously monitor the instantaneous values ​​of the power vehicle output voltage and the grid-side voltage, and execute the grid-connected power supply process after triggering the interlocking and coordinated control.

[0031] S4. If off-grid power supply is triggered, the load impact component is identified by the current sensor, and it is verified whether the peak value of the impact exceeds the amplitude threshold and whether the duration exceeds the time threshold.

[0032] S5. If the verification fails or the total power exceeds the limit, the load branch is cut off step by step starting from the lowest priority load according to the preset load classification library, and the impulse verification and power check are re-executed. This process is repeated until the verification passes and the total power does not exceed the limit.

[0033] S6. If the verification passes and the total power does not exceed the limit, the off-grid power supply process is matched, and the timing-based hierarchical loading control is executed according to the number of adjustment stages determined based on the load type and the total load ratio.

[0034] Regarding step S2, the specific rules for determining the power supply mode are as follows: when the grid side is connected and the power change rate does not exceed the first preset threshold, grid-connected power supply is triggered; when the grid side is disconnected or the power change rate exceeds the first preset threshold, off-grid power supply mode is triggered.

[0035] Understandably, the setting of the first preset threshold for the power change rate needs to be combined with the grid stability requirements, the power regulation capability of the power supply vehicle, and the load characteristics. It is usually determined based on the maximum power fluctuation range allowed by the grid, such as 5%-15% of the rated power. This is to avoid the power supply continuity being affected by frequent switching of power supply modes due to short-term small power fluctuations, and to switch to off-grid mode in a timely manner when the power change is too large and may threaten the grid stability, so as to ensure power supply safety.

[0036] Regarding step S3, the specific steps of the trigger-locking coordinated control are as follows: calculate the amplitude difference, frequency difference, and phase angle difference between the output voltage of the power supply vehicle and the grid side voltage based on the instantaneous value collected by the voltage transformer.

[0037] If any difference exceeds the preset tolerance range, the mechanical interlocking device will be triggered to lock the grid-connected switch operating mechanism until all differences return to the tolerance range.

[0038] If all differences are continuously compared, and the tolerance conditions are met for more than the preset number of power frequency cycles, the lockout is released.

[0039] It should be noted that the preset tolerance range of amplitude difference is mainly based on the capacity matching relationship between the power supply vehicle and the power grid, the equipment's ability to withstand inrush current, and the industry grid connection standards. It is usually set to ±2% to ±5% of the rated voltage. For example, a 380V system is set to ±7.6V to ±19V. It is necessary to balance grid connection safety and operational flexibility, avoid frequent triggering of interlocks due to small amplitude fluctuations, and prevent excessive difference from causing equipment damage.

[0040] The preset tolerance range for frequency difference is based on the rated frequency of the power grid, such as 50Hz or 60Hz, and the frequency adjustment accuracy of the power vehicle. It is generally ±0.1Hz to ±0.5Hz. When setting it, the impact of frequency difference on active power exchange must be considered. The tolerance must be adapted to the response speed of the power vehicle speed control system. Operation is only allowed when the frequency is close to synchronization.

[0041] The preset tolerance range for phase angle difference is mainly based on the phase synchronization accuracy requirements and the system's reactive power impact tolerance, and is usually set to ± To ± Since the phase angle difference directly determines the magnitude of the reactive circulating current at the moment of grid connection, the tolerance needs to be combined with the phase measurement error of the voltage transformer.

[0042] It should also be noted that the preset number of power frequency cycles can be set based on the sampling frequency of the voltage signal, such as sampling 20 points per 20ms power frequency cycle, typically 3-5 power frequency cycles. This can filter out instantaneous compliance signals, ensuring that amplitude difference, frequency difference, and phase angle difference remain stable within the tolerance range, avoiding misinterlocking due to short-term fluctuations, and improving the reliability of grid connection operation.

[0043] Please see Figure 3 As shown, in step S3, the grid-connected power supply process includes: S31, determining whether the amplitude difference, frequency difference, and phase angle difference are all lower than the corresponding preset thresholds.

[0044] S32. If all conditions are met, start the three-channel PI regulator to adjust each difference value in the preset priority order, and when the number of consecutive power frequency cycles that meet the conditions exceeds the set value, perform grid connection.

[0045] Understandably, the default priority order is usually phase angle difference > frequency difference > amplitude difference.

[0046] It is also understood that the set value of the number of power frequency cycles is the same as the preset number of power frequency cycles set when judging the tolerance conditions, specifically 5 cycles. By monitoring for multiple consecutive cycles, it can be ensured that the amplitude difference, frequency difference, and phase angle difference are within the corresponding preset thresholds and are not instantaneous fluctuations, but rather a steady state achieved after PI adjustment. This avoids misjudgment of grid connection due to short-term disturbances in the power grid or power vehicle output. At the same time, the duration of 5 cycles can meet the stability verification requirements without excessively delaying the grid connection response speed. Especially in emergency power supply scenarios, it can ensure grid connection safety while taking into account the timeliness of power supply.

[0047] S33. If any parameter exceeds the limit, dynamically adjust the PI parameter.

[0048] S34. If only the phase angle difference exceeds the limit, inject virtual damping current into the H-bridge converter. If the phase angle difference is within the second threshold and the duration exceeds the preset duration, connect to the grid immediately.

[0049] It should be noted that when only the phase angle difference is greater than the corresponding preset threshold, the amplitude / frequency correction amount should also be limited to within ±2% of the device's rated value.

[0050] Understandably, in scenarios where only the phase angle difference exceeds the preset threshold, limiting the amplitude and frequency correction to within ±2% of the rated value aims to avoid new parameter deviations caused by excessive adjustment of amplitude or frequency, prevent interference with the phase angle difference correction process, ensure that control resources are concentrated on phase synchronization, and maintain the amplitude and frequency in a stable state close to the grid side. This creates a smooth foundation for the phase angle difference to converge to grid connection conditions and reduces the risk of system oscillation that may be caused by multi-parameter linkage adjustment.

[0051] It should be added that if the phase angle difference exceeds the second threshold, virtual damping current must be continuously injected through the H-bridge converter to suppress the expansion of the phase deviation, while the changing trend of the phase angle difference is monitored in real time. If the phase angle difference still does not converge to within the second threshold after a certain adjustment time, the phase angle difference over-limit protection mechanism must be triggered, such as extending the adjustment time, increasing the damping current injection intensity, or temporarily blocking grid connection operation when the deviation is too large and may threaten system safety. Grid connection operation can only be allowed again after the phase angle difference is adjusted to within the second threshold and the maintenance time requirement is met, to ensure the phase synchronization accuracy and system stability at the moment of grid connection.

[0052] The setting of the second threshold should focus on the phase synchronization accuracy and system tolerance at the moment of grid connection. It is usually determined based on the rated frequency, voltage level and load characteristics of the power supply vehicle and the power grid. Generally, the phase angle difference is taken to be within the range of ±5° to ±10°, and the specific value needs to be verified by simulation to ensure that the inrush current during grid connection within this range does not exceed the equipment tolerance threshold. This ensures both synchronization accuracy to reduce grid connection impact and reasonable fault tolerance space for phase adjustment.

[0053] The preset maintenance duration setting needs to be combined with the stability requirements of the phase angle difference, usually set to 0.5 seconds to 2 seconds. It can be adjusted according to the dynamic response speed to confirm that the phase angle difference is in a stable state within the second threshold rather than a momentary fluctuation. This avoids accidental grid connection due to short-term, accidental phase convergence and ensures the continuity and reliability of the phase synchronization state during grid connection.

[0054] S35. If only the amplitude difference exceeds the limit, the compensation amount output by the grid voltage feedforward compensation circuit is introduced, and the PWM enable signal of the phase and frequency regulator is frozen through AND gate logic, and the grid-connected allowable amplitude difference is adjusted to the safe ratio of the rated voltage.

[0055] When only the amplitude difference exceeds the limit, the compensation amount introduced by the grid voltage feedforward compensation circuit can quickly suppress the amplitude deviation and improve the regulation response speed. By freezing the PWM enable signal of the phase and frequency regulator through AND gate logic, the adjustment action of non-exceeding parameters can be prevented from interfering with the amplitude correction process, ensuring that the regulation target is singular and clear. At the same time, adjusting the grid-permitted amplitude difference to a safe proportion of the rated voltage can reduce the impact of amplitude fluctuations on grid-connected safety. These three operations work together to achieve accurate and safe correction of amplitude deviation, ensuring system stability.

[0056] It should be added that the safety ratio setting of the rated voltage should be based on the equipment's withstand voltage limit, power grid stability requirements, and grid connection standards. Usually, a smaller ratio of the rated voltage is taken, such as ±1% to ±3%, which leaves room for amplitude adjustment and ensures that the deviation is within a safe range, so as to avoid impact on the equipment and the power grid.

[0057] S36. If only the frequency difference exceeds the limit, activate the cumulative error clearing module of the phase-locked loop to reset the D flip-flop.

[0058] Understandably, phase-locked loops (PLLs) accumulate errors over long-term operation due to factors such as signal noise and circuit drift. The cumulative error clearing module eliminates these errors to ensure PLL accuracy. When this module is activated, it triggers a reset signal, which acts on the D flip-flops in the system, resetting them.

[0059] S37. If two or more parameters exceed the limit, the grid voltage feedforward compensation circuit will output compensation amount and trigger the discharge MOSFET enable signal of the IGBT soft turn-off protection circuit.

[0060] Understandably, when two or more parameters exceed limits simultaneously, such as phase angle difference, amplitude difference, and frequency difference, the deviation from the stable state is more severe, easily leading to risks such as grid inrush current and drastic voltage fluctuations. Introducing a grid voltage feedforward compensation circuit to output compensation can predict and suppress grid disturbances in advance, quickly reducing parameter deviations and minimizing the impact on system stability. Simultaneously, triggering the discharge MOSFET enable signal of the IGBT soft turn-off protection circuit can avoid overvoltage and overcurrent surges caused by IGBT hard turn-off through soft turn-off, and release excess energy through the discharge circuit to prevent overload damage to devices caused by multiple parameter exceedances. These dual measures work together to ensure equipment safety and grid operation stability.

[0061] In the above-mentioned step S31, the preset threshold for amplitude difference is mainly based on the normal fluctuation range of the grid voltage and the inrush current limit when the power supply vehicle is connected to the grid. It is usually set to 5% of the rated output voltage of the power supply vehicle. The normal fluctuation range generally allows ±5% of the rated voltage deviation. That is, when the amplitude difference is ≤5% of the rated voltage, the inrush current at the moment of grid connection can be controlled within 2-3 times the rated current of the equipment, which is within the safe tolerance range of power equipment such as circuit breakers and transformers. At the same time, this threshold provides sufficient correction margin for the amplitude channel PI regulator, ensuring that in the reference regulation mode, the deviation can be converged to a smaller safety window, such as ≤2% of the rated voltage, through conventional proportional-integral regulation, thus balancing regulation accuracy and equipment safety.

[0062] The preset threshold for frequency difference is typically set to 0.5Hz. This value is based on the standard allowable deviation of the grid frequency and the coupling effect of frequency on the phase angle. After multiple verifications, when the frequency difference is ≤0.5Hz, the drift rate of the phase angle difference can be controlled within approximately 3.14 rad / s. The speed control system of the power vehicle, such as the diesel generator governor and the frequency regulation module of the energy storage converter, has sufficient response time to eliminate the frequency difference through PI regulation, preventing the phase angle difference from rapidly exceeding the limit due to the accumulation of frequency deviation. At the same time, this threshold can balance the response speed and stability of frequency regulation, preventing frequent oscillations in regulation due to an excessively small threshold.

[0063] The preset threshold for phase angle difference is usually set to The setting of this value mainly considers the impact of phase angle difference on the grid-connected active power. After multiple verifications, when the phase angle difference is ≤ At this time, the active power surge and phase angle difference have an approximately linear relationship, and the surge value can be controlled within 8.7% of the rated power, which is within the tolerance range of the load and the power grid. Furthermore, The threshold provides a reasonable correction range for the phase channel PI regulator. In the reference adjustment mode, the phase angle difference can be quickly converged to the safe grid-connected range of ≤1° by conventional proportional-integral adjustment, avoiding excessive impact due to an excessively large threshold or excessive adjustment due to an excessively small threshold.

[0064] The dynamic adjustment of the PI parameter in step S33 above includes: A1. If only the phase angle difference exceeds the limit, adjust the proportional coefficient, determine the boost ratio based on the threshold table of the excess ratio, and calculate the adjustment amount.

[0065] A2. If only the amplitude difference exceeds the limit, adjust the proportional coefficient and integral time constant. Based on the over-limit ratio, query the threshold table to determine the increase and decrease ratios, and calculate the adjustment amount in combination with the feedforward compensation output.

[0066] A3. If only the frequency difference exceeds the limit, adjust the proportional coefficient and the integral time constant, and determine the adjustment amount by consulting the threshold table based on the excess ratio and the absolute value of the frequency difference.

[0067] A4. If multiple parameters exceed the limits, adjust the proportional coefficient and integral time constant, query the threshold table based on the excess proportion of each parameter, and calculate the final adjustment amount through the multi-parameter coupling factor.

[0068] It should be added that the over-limit ratio query threshold table is classified vertically by over-limit parameter type, such as phase angle difference, amplitude difference, and frequency difference, and horizontally divided according to the over-limit ratio range of each parameter, such as 0-20%, 20%-50%, etc. Each interval cell is marked with the preset benchmark ratio coefficient and preset benchmark integral time constant of the parameter under the over-limit degree. For phase angle difference, only the benchmark ratio coefficient can be set. Through the dual matching of parameter type and over-limit ratio, the corresponding benchmark value can be directly extracted, providing basic parameters for subsequent calculation of adjustment amount.

[0069] Furthermore, the data in the table integrates theoretical calculations, simulation experiments, and field data accumulation. First, the basic intervals and benchmark value ranges are derived based on equipment parameters and industry standards. Then, different over-limit scenarios are simulated to iteratively calibrate the benchmark proportional coefficients and integral time constants corresponding to each interval, ensuring compliance with system stability requirements. Finally, based on the actual performance of parameter deviations and feedback on adjustment effects during field operation, the interval division and numerical settings are dynamically optimized to form threshold table data adapted to specific application scenarios.

[0070] Understandably, the proportional gain affects the adjustment speed, while the integral time constant affects steady-state accuracy. When the phase angle significantly exceeds the limit, the proportional gain needs to be increased to accelerate the response, but oscillations must be avoided. When approaching the tolerance, the proportional gain needs to be decreased and the integral time constant increased to suppress overshoot. When the amplitude difference slightly exceeds the threshold, the integral time constant is slightly shortened to avoid excessive integral action leading to overshoot; when the amplitude difference significantly exceeds the threshold, the integral time constant is significantly shortened to accelerate the steady-state correction speed. This correlation method retains the direct linkage between the proportional gain and feedforward compensation, and also achieves dynamic adaptation of the integral time constant when the deviation exceeds the proportional gain, thus improving control coordination.

[0071] Furthermore, the calculation of the adjustment amount is performed by a deviation classifier: the preset benchmark ratio coefficient and the preset benchmark integral time constant corresponding to the over-limit parameter are extracted from the over-limit ratio query threshold table.

[0072] The excess ratio of the excess parameter is compared with the preset threshold of the corresponding excess parameter, and the corresponding increase, decrease or extension ratio threshold is selected.

[0073] The PI parameter adjustment amount is calculated based on the product of the proportional threshold and the over-limit ratio, combined with the corresponding preset benchmark parameter value.

[0074] In a specific embodiment, the specific execution process of the deviation classifier is as follows: B1. If the proportion of the phase angle difference exceeding the preset threshold is greater than the preset phase excess proportion, the first boosting ratio threshold under the phase angle difference over-limit adjustment is called as the rated boosting ratio threshold; otherwise, the second boosting ratio threshold is called as the rated boosting ratio threshold.

[0075] B2. The final boost ratio is obtained by multiplying the ratio of the phase angle difference exceeding the preset threshold by the rated boost ratio threshold. The adjustment amount of the boost ratio is obtained by multiplying the sum of 1 and the final boost ratio by the preset benchmark boost ratio coefficient when the phase angle difference exceeds the limit.

[0076] B3. If the amplitude difference exceeds the preset threshold by a greater proportion than the preset amplitude excess proportion, the first reduction ratio threshold under amplitude difference over-limit adjustment is called as the rated reduction ratio threshold; otherwise, the second reduction ratio threshold is called as the rated reduction ratio threshold.

[0077] B4. The final reduction ratio is obtained by multiplying the ratio of amplitude difference exceeding the preset threshold by the rated reduction ratio threshold. The sum of the reduction ratio and the original ratio is multiplied by the preset baseline integration time constant when the amplitude difference exceeds the limit to obtain the adjustment amount of the integration time constant. The reduction ratio is presented in negative form.

[0078] B5. If the frequency difference exceeds the preset threshold by a greater percentage than the preset frequency difference exceeds the preset threshold, the first extension ratio threshold under the frequency difference over-limit adjustment is called as the rated extension ratio threshold; otherwise, the second extension ratio threshold is called as the rated extension ratio threshold.

[0079] B6. The final extension ratio is obtained by multiplying the ratio of frequency difference exceeding the preset threshold by the rated extension ratio threshold. The sum of 1 and the final extension ratio is multiplied by the preset reference integration time constant when the amplitude difference exceeds the limit to obtain the adjustment amount of the integration time constant.

[0080] Understandably, the preset phase deviation ratio can be set based on the degree of influence of the phase angle difference on the synchronization stability. It is usually a critical ratio for judging the severity of the phase deviation, such as 20%-30%. When the proportion of the phase angle difference exceeding the preset threshold exceeds this value, it is judged as a serious over-limit, and vice versa, it is a slight over-limit. This provides a basis for selecting different boost ratio thresholds.

[0081] The first boost ratio threshold for phase angle difference over-limit adjustment is suitable for scenarios with severe phase over-limit, requiring a stronger adjustment force, and is set relatively high, such as 0.8. The second boost ratio threshold is suitable for slight over-limit, and is set relatively low, such as 0.6. Both settings are based on the response speed of phase adjustment and the system's anti-oscillation requirements, and are calibrated using historical adjustment data.

[0082] Understandably, the preset amplitude excess ratio can be set based on the impact of amplitude difference on voltage stability. It is usually a critical value to distinguish the degree of amplitude deviation, such as 15%-25%. When the amplitude difference exceeds the preset threshold by more than this value, it is judged as a serious over-limit, and otherwise it is a slight over-limit. It is used to select different reduction ratio thresholds.

[0083] The first reduction ratio threshold under amplitude difference over-limit adjustment is suitable for severely over-limit amplitudes requiring stronger reduction, and should be set higher, such as 0.7-0.9. The second reduction ratio threshold is suitable for slightly over-limit amplitudes, and should be set lower, such as 0.3-0.5. Both thresholds are designed to balance the accuracy requirements of amplitude adjustment with load tolerance, avoiding over-adjustment that could cause voltage fluctuations.

[0084] It is also understandable that the preset frequency excess ratio can be set based on the impact of frequency difference on active power balance. It is usually a critical ratio for judging the degree of frequency deviation, such as 10%-20%. When the frequency difference exceeds the preset threshold by more than this value, it is judged as a serious over-limit, and otherwise it is a slight over-limit. It is used to select different extension ratio thresholds.

[0085] The first extension ratio threshold for frequency difference over-limit adjustment is suitable for severe frequency over-limits, requiring a longer adjustment time, and is set relatively high, such as 0.6-0.8. The second extension ratio threshold is suitable for slight over-limits, and is set relatively low, such as 0.2-0.4. Both are based on the inertial characteristics of frequency adjustment, balancing response speed and system stability.

[0086] The reference proportional gain is set to a value of 0.5-1.2 based on the sensitivity requirements of phase adjustment to ensure the response speed of phase adjustment. The reference integral time constant is set to a value of 0.1-0.5s based on the stability requirements of amplitude and frequency adjustment to avoid over-integration that could cause system oscillation. Both values ​​are determined through PID control experience and simulation data.

[0087] Furthermore, the multi-parameter coupling factor is specifically calculated by performing the following process: C1, receiving the proportional coefficient adjustment signal and the integral time constant adjustment signal obtained independently from the voltage, frequency and phase angle difference.

[0088] C2. Input the proportional coefficient adjustment signal to the maximum value selector circuit, and select the maximum value as the final proportional coefficient adjustment output.

[0089] C3. The integral time constant adjustment signal is input to the dominant parameter selector circuit. Based on the preset priority logic, the adjustment amount corresponding to the dominant out-of-range parameter is selected as the final integral time constant adjustment output. The dominant parameter selector circuit is executed by a programmable logic array, and its priority order is phase angle difference > frequency difference > amplitude difference.

[0090] C4. Input the final proportional coefficient adjustment and integral time constant adjustment to the limiting protection circuit and output them after limiting them to the safe range.

[0091] Understandably, the maximum value selector circuit is composed of multiple stages of high-speed digital comparators.

[0092] It should be added that the limiting protection circuit includes: a proportional coefficient limiting sub-circuit and an integral time constant limiting sub-circuit. The proportional coefficient limiting sub-circuit uses a bidirectional Zener diode, such as the BZX84C series, for voltage clamping. The clamping voltage value is determined by the product of the reference voltage and the limiting ratio.

[0093] The integral time constant limiting sub-circuit uses a window comparator such as LM393 to drive an analog switch to switch the integral resistor network with different resistance values.

[0094] It should also be noted that the safe range setting of the proportional coefficient adjustment amount needs to be combined with the system stability margin, dynamic response speed and load characteristics. It is usually based on the premise of ensuring that the system does not overshoot or oscillate excessively. Generally, the specific range is determined by theoretically calculating the critical stability parameters of the system and combining them with actual debugging experience.

[0095] The safe range for adjusting the integral time constant needs to balance the ability to eliminate steady-state errors with system stability. It is usually determined by simulation analysis and on-site debugging based on load disturbance characteristics, system inertia, and allowable adjustment time.

[0096] In step S4, the load impact component can be identified by acquiring the load current signal in real time through a current sensor. After filtering to remove the steady-state component, the sudden current component that appears in a short time is extracted, which is the load impact component. This process can be combined with a differentiating circuit to enhance the sensitivity to current sudden changes and improve the identification accuracy.

[0097] The threshold value for the peak impact should be set based on the system's rated load capacity and the tolerance limit of key equipment. It is usually 1.5 to 3 times the rated current, and the specific multiple can be adjusted according to the characteristics of the equipment.

[0098] The duration of the time threshold setting needs to distinguish between instantaneous impacts and continuous overloads. It is generally set to several hundred milliseconds to several seconds, such as 200ms-5s. Short-term impacts, such as motor startup, are usually allowed. Impacts exceeding this duration are judged as abnormal states that require intervention. The specific value is determined experimentally based on the system response speed and load characteristics.

[0099] If the verification fails or the total power exceeds the limit in step S5, the system will call the preset load classification library. This library is divided into levels according to the importance of the load, such as critical loads (e.g., emergency lighting, medical equipment), secondary loads (e.g., communication equipment), and general loads (e.g., air conditioning, lighting). Starting from the lowest priority general load, the system will sequentially cut off its power supply branch by controlling the corresponding circuit breaker or relay. After each level is cut off, the total power will be re-detected until the total power returns to the safe range or only the highest priority load is retained.

[0100] The specific off-grid power supply process described in step S6 is as follows: The load type is identified through the load detection unit, including linear loads, nonlinear loads, and impulsive loads.

[0101] Connect according to load type: output no-load voltage and connect to linear load.

[0102] The nonlinear loads are connected sequentially according to the adjustment stage number after the first preset time delay.

[0103] After a second preset time delay, the impact load is connected according to the adjusted number of stages, and the current limiting protection is triggered simultaneously.

[0104] The first preset duration is shorter than the second preset duration.

[0105] Understandably, a linear load is defined as a load with a sinusoidal current waveform and a constant power factor; a nonlinear load is defined as a load with a current waveform containing high-order harmonics and a total harmonic distortion rate >15%; and an impulsive load is defined as a load with a short-time power offset percentage >20% and an impulsive load percentage >30%.

[0106] Understandably, the first preset time, i.e., the delay before connecting a nonlinear load, is relatively short, such as 0.5-2 seconds. This is because although nonlinear loads may generate harmonics, the impact is small, and it is sufficient to wait for the linear load to stabilize. The second preset time, i.e., the delay before connecting an impulsive load, is relatively long, such as 2-5 seconds. This is because impulsive loads have large starting currents, and more time needs to be reserved for the preceding loads and the system to stabilize, avoiding superimposed impacts that could cause voltage or frequency fluctuations.

[0107] The specific process for determining the number of adjustment stages in step S6 includes: identifying the types of all loads currently to be connected, and determining the highest priority load type among them, wherein the priority order is linear load > nonlinear load > impact load.

[0108] If the highest priority load type is linear load, the adjustment stage number is the lowest stage number.

[0109] If the highest priority load type is a non-linear load, calculate the percentage of the total power of all loads to be connected to the rated output power of the power supply vehicle to obtain the total load ratio, and set the baseline stage number as the first intermediate value. When the total load ratio exceeds the first preset ratio, the final stage number is increased by one level compared to the baseline stage number.

[0110] If the highest priority load type is an impact load, the baseline stage number is set to the second intermediate value. When the total load percentage exceeds the second preset ratio, the final stage number is increased by one level compared to the baseline stage number. When the total load percentage exceeds the third preset ratio, the final stage number is increased by one level compared to the stage number when it exceeds the second preset ratio.

[0111] It should be added that the overall startup process is divided into several power increment steps. The more stages, the smoother the startup process, but the more complex the control becomes. Therefore, the number of stages needs to be adjusted and confirmed.

[0112] It should also be noted that the minimum number of stages refers to the fixed adjustment stages corresponding to linear loads, which is the fewest adjustment steps among all load types. When setting this number, based on the characteristics of linear loads—no harmonic interference and stable operation—the principle is to quickly complete power adaptation without causing system fluctuations. It is typically set to 1-2 stages to ensure efficient adjustment while simplifying control logic.

[0113] Understandably, the first intermediate value is the baseline adjustment stage number for the nonlinear load, that is, the initial stage number when the overall load ratio does not exceed the first preset ratio. The setting needs to be combined with the harmonic characteristics of the nonlinear load and take a value slightly higher than the minimum stage number, such as 2-3 stages, so as to suppress the superposition effect of harmonics without excessively increasing the adjustment complexity.

[0114] Among them, the minimum number of stages < the first intermediate value < the second intermediate value; the second preset ratio < the third preset ratio.

[0115] The first preset ratio is the comprehensive load ratio threshold for nonlinear loads. It sets the harmonic amplification risk under high nonlinear load ratio, usually 40%-50%. At this point, the impact of harmonics on the system is significantly enhanced, and it is necessary to refine the adjustment by increasing the number of stages.

[0116] The second intermediate value is the baseline adjustment stage number for impact loads, which is the initial stage number when the overall load ratio does not exceed the second preset ratio. It needs to be set higher than the first intermediate value, such as 3-4 stages, to cope with the impact of the initial impact on system stability.

[0117] The second preset ratio is the first comprehensive load percentage threshold for impact loads, set based on the risk of impact superposition under medium load percentage, usually 30%-40%.

[0118] The third preset ratio is a higher overall load ratio threshold for impact loads, which focuses on the overload risk under high load ratios, and is usually set to 60%-70%.

[0119] It is also understandable that the rated output power of the power supply vehicle is the inherent parameters of the equipment, such as 50kVA or 100kVA, which are pre-stored in the memory of the control unit.

[0120] Please see Figure 4 As shown, the specific control of the time-series graded loading control in step S6 is as follows: real-time statistics of the load percentage growth rate, calling the power increment template corresponding to the adjustment stage number and load type, wherein the template defines a predefined ratio sequence of the power limit of each stage relative to the total load power.

[0121] If the load percentage growth rate is positive, the power limits for each stage are applied sequentially from low to high according to the order defined in the template.

[0122] If the load percentage growth rate is negative, the power limits for each stage will be reduced sequentially from high to low according to the order defined in the template.

[0123] When the load percentage exceeds the preset warning value, the power limit is maintained at 100% and an overload warning is triggered.

[0124] It should be added that the power increment template settings corresponding to the number of adjustment stages and load type need to be matched with the load characteristics and the number of stages. For linear loads, the template should have fewer stages, such as 1-2 stages, with a rapid increment ratio, e.g., from 50% to 100%, as linear loads are stable and do not experience severe surges. For nonlinear loads, the template should have moderate stages, such as 2-3 stages, with a gradual increment ratio, e.g., increasing in a sequence of 30%, 60%, and 100%, to suppress the effects of harmonic superposition. For impulsive loads, the template should have more stages, such as 3-5 stages, with a stepped, slow increment ratio, e.g., increasing in a sequence of 20%, 40%, 60%, 80%, and 100%. The more stages, the finer the increment ratio, avoiding current surges caused by sudden power changes.

[0125] It should be noted that the values ​​given above are only example values. The proportional sequence of each template needs to be verified through load start-up experiments to ensure that the power limit of each stage can not only adapt to the load start-up requirements, but also maintain the stability of system voltage and frequency.

[0126] In another specific embodiment, the control unit is also configured with a dynamic mode switching engine: during grid-connected power supply, if the load surge characteristics are detected to exceed the grid-connected adjustment threshold, a seamless switch from grid-connected to off-grid is executed. During off-grid power supply, if the grid returns to stability and the synchronization conditions are met, a seamless switch from off-grid to grid-connected is executed.

[0127] Seamless switching is achieved in the following way: grid-connected to off-grid: before disconnecting the grid-connected switch, control the power conversion unit to switch to voltage source mode and establish the output voltage.

[0128] The synchronization condition is that the voltage amplitude, frequency, and phase angle of the mobile power vehicle output are the same as those of the grid side.

[0129] The above content is merely an example and illustration of the concept of the present invention. Those skilled in the art can make various modifications or additions to the specific embodiments described, or use similar methods to replace them, as long as they do not deviate from the concept of the invention or exceed the scope defined by the present invention, and all such modifications and additions should fall within the protection scope of the present invention.

Claims

1. A large mobile storage power supply vehicle emergency power supply system, comprising a vehicle-mounted energy storage unit, a power conversion unit, a PWM signal generation unit, a load monitoring unit and a control unit, characterized in that, The control unit comprises: The on-off state of the power grid side is collected, the total power of the load side is obtained through the load monitoring unit, and the power change rate is calculated based on the differential circuit; The power supply mode is determined according to the on-off state and the power change rate, and the power supply mode comprises grid-connected power supply and off-grid power supply; If the grid-connected power supply is triggered, the instantaneous values of the power supply vehicle output voltage and the power grid side voltage are continuously monitored, the grid-connected power supply process is executed after the latching cooperative control is triggered; If the off-grid power supply is triggered, the load impact component is identified through the current sensor, and it is checked whether the impact peak value exceeds the amplitude threshold value and the duration exceeds the time threshold value; If the check fails or the total power is out of limit, the load branch is step by step cut off from the lowest priority load according to the preset load grading library, and the impact check and power check are re-executed, and the process is repeated until the check is passed and the total power is not out of limit; If the check is passed and the total power is not out of limit, the off-grid power supply process is matched, and the timing hierarchical loading control is executed according to the adjustment stage number determined based on the load type and the total load proportion; Among all the load types to be connected, the highest priority load type is determined, if the highest priority load type is a linear load, the adjustment stage number is the lowest stage number; if the highest priority load type is a nonlinear load or an impact load, the adjustment stage number is gradually increased according to the total load proportion exceeding the preset proportion on the basis of the reference stage number; and the adjustment stage number is the number of times of several power incremental steps; According to the load proportion growth rate, the power incremental template corresponding to the adjustment stage number and the load type is called, and the timing hierarchical loading control is performed.

2. The emergency power supply system of a large mobile storage and charging power source vehicle according to claim 1, characterized in that: The specific determination rules of the power supply mode are as follows: When the power grid side is connected and the power change rate does not exceed the first preset threshold value, the grid-connected power supply is triggered; When the power grid side is disconnected or the power change rate exceeds the first preset threshold value, the off-grid power supply mode is triggered.

3. The emergency power supply system of a large mobile storage and charging power source vehicle according to claim 1, characterized in that: The specific steps of triggering the latching cooperative control are as follows: The amplitude difference, frequency difference and phase angle difference of the power supply vehicle output voltage and the power grid side voltage are calculated according to the instantaneous values collected by the voltage transformer; If any difference value exceeds the preset tolerance range, the mechanical interlocking device is triggered to lock the grid-connected switch operating mechanism until all difference values are within the tolerance range; If all the difference values continuously meet the tolerance condition for more than a preset power frequency cycle number, the latching is released.

4. A large mobile storage and charging power supply vehicle emergency power supply system as claimed in claim 3, characterized in that: The grid-connected power supply process comprises: It is judged whether the amplitude difference, frequency difference and phase angle difference are all lower than the corresponding preset threshold value; If all the conditions are met, the three-channel PI regulator is started to adjust each difference value in the preset priority order, and when the number of power frequency cycles that continuously meet the conditions exceeds the set value, the grid connection is performed; If any parameter is out of limit, the PI parameter is dynamically adjusted; If only the phase angle difference is out of limit, a virtual damping current is generated by the H-bridge converter, and if the phase angle difference is within the second threshold value and the maintenance time exceeds the preset maintenance time, the grid connection is immediately performed; If only the amplitude difference is out of limit, the compensation amount output by the grid voltage feedforward compensation circuit is introduced, the PWM enable signals of the phase and frequency regulators are frozen through the AND gate logic, and the grid connection permission amplitude difference is adjusted to a safe proportion of the rated voltage; If only the frequency difference is out of limit, the cumulative error reset module of the phase-locked loop is activated to reset the D flip-flop. If two or more parameters exceed the limit, introduce grid voltage feedforward compensation circuit output compensation, and trigger IGBT soft shutdown protection circuit discharge MOSFET enable signal.

5. A large mobile storage and charging power supply vehicle emergency power supply system as claimed in claim 4, characterized in that: The dynamic adjustment of the PI parameters comprises: If only the phase angle difference exceeds the limit, adjust the proportional coefficient, determine the improved proportion based on the threshold table of the exceeded proportion, and calculate the adjustment amount; If only the amplitude difference exceeds the limit, adjust the proportional coefficient and the integral time constant, determine the improved and reduced proportions based on the threshold table of the exceeded proportion, and calculate the adjustment amount in combination with the feedforward compensation output; If only the frequency difference exceeds the limit, adjust the proportional coefficient and the integral time constant, determine the adjustment amount based on the threshold table of the exceeded proportion and the absolute value of the frequency difference; If multiple parameters exceed the limit, adjust the proportional coefficient and the integral time constant, query the threshold table of each parameter based on the exceeded proportion, and calculate the final adjustment amount through a multi-parameter coupling factor.

6. A large mobile storage and charging power supply vehicle emergency power supply system as claimed in claim 5, characterized in that: The calculation of the adjustment amount is performed by a deviation classifier: Extract the preset reference proportional coefficient and the preset reference integral time constant corresponding to the exceeded parameter from the threshold table of the exceeded proportion; Compare the exceeded proportion of the exceeded parameter with the preset threshold value of the corresponding exceeded parameter, and select the proportional threshold value of the corresponding improved, reduced, or extended proportion; Calculate the PI parameter adjustment amount based on the product of the proportional threshold value and the exceeded proportion, and in combination with the corresponding preset reference parameter value.

7. A large mobile storage and charging power supply vehicle emergency power supply system as claimed in claim 5, characterized in that: The multi-parameter coupling factor is specifically calculated and executed by the following process: Receive the proportional coefficient adjustment amount signal and the integral time constant adjustment amount signal calculated independently by the voltage, frequency, and phase angle difference; Input the proportional coefficient adjustment amount signal into a maximum selector circuit, select the maximum value as the final proportional coefficient adjustment amount output; Input the integral time constant adjustment amount signal into a dominant parameter selector circuit, select the adjustment amount corresponding to the dominant exceeded parameter as the final integral time constant adjustment amount output based on the preset priority logic, and the dominant parameter selector circuit is executed by a programmable logic array, with the priority order being phase angle difference > frequency difference > amplitude difference; Output the final proportional coefficient adjustment amount and the integral time constant adjustment amount after limiting them in the safe interval by the amplitude limiting protection circuit.

8. The emergency power supply system of a large mobile storage and charging power source vehicle according to claim 1, characterized in that: The specific determination process of the adjustment stage number comprises: Identify the types of all loads to be connected, and determine the highest priority load type, with the priority order being linear load > nonlinear load > impact load; If the highest priority load type is linear load, the adjustment stage number is the lowest stage number; If the highest priority load type is nonlinear load, calculate the percentage of the total power of all loads to be connected to the rated output power of the power supply vehicle to obtain the total load percentage, set the reference stage number to the first intermediate value, and when the total load percentage exceeds the first preset proportion, increase the final stage number by one level compared to the reference stage number; If the highest priority load type is impact load, set the reference stage number to the second intermediate value, and when the total load percentage exceeds the second preset proportion, increase the final stage number by one level compared to the reference stage number, and when the total load percentage exceeds the third preset proportion, increase the final stage number by one level compared to the stage number when the total load percentage exceeds the second preset proportion; Among them, the minimum stage number < the first intermediate value < the second intermediate value; the second preset ratio < the third preset ratio.

9. A large mobile storage and charging power supply vehicle emergency power supply system as claimed in claim 1, characterized in that: The off-grid power supply process is specifically as follows: The load type is identified by the load detection unit, including linear load, nonlinear load and impact load; Access by load type classification: Output the no-load voltage and put in the linear load; After delaying for a first preset time length, sequentially access the nonlinear load according to the adjustment stage number; After delaying for a second preset time length, access the impact load according to the adjustment stage number, and trigger the current limiting protection at the same time; Among them, the first preset time length is less than the second preset time length.

10. The emergency power supply system of a large mobile storage and charging power source vehicle according to claim 1, characterized in that: The specific control of the timing hierarchical loading control is as follows: Real-time statistical load proportion growth rate, call the power increment template corresponding to the adjustment stage number and the load type, the template defines the predefined proportion sequence of each stage power limit value relative to the total load power; If the load proportion growth rate is positive, sequentially apply each stage power limit value from low to high in the order defined by the template; If the load proportion growth rate is negative, sequentially decrease each stage power limit value from high to low in the order defined by the template; When the load proportion is greater than the preset warning value, maintain 100% power limit value and trigger the overload warning.

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