Rectifier current regulation and control system and method based on digital control

Abstract

The invention provides a rectifier current regulation and control system and method based on digital control, and relates to the technical field of current regulation and control. When the output voltage error of the direct current side of the rectifier exceeds a preset voltage error threshold value, control interruption is triggered immediately, and then an event trigger point when the power load of the rectifier changes suddenly is determined; performing drop trend analysis on the output voltage in the next current inner loop control period to obtain a voltage drop trend in the next current inner loop control period; further performing feed-forward compensation on the output current of the rectifier at the beginning of the next current inner loop control period to obtain a feed-forward current compensation amount of the rectifier at the beginning of the next current inner loop control period; and then a feed-forward current compensation instruction is generated, and then the output current of the rectifier at the beginning of the next current inner loop control period is adjusted. The direct-current side current can be rapidly stabilized when the power load of the rectifier suddenly changes.

Description

A rectifier current regulation system and method based on digital control Technical Field

[0001] This application relates to the field of current regulation technology, and more specifically, to a rectifier current regulation system and method based on digital control. Background Technology

[0002] Current regulation technology, as a key fundamental capability in power electronic control systems, plays a crucial role in ensuring that power conversion devices maintain stable and controllable current output under different operating conditions. As various power loads exhibit higher dynamism, the system places higher demands on the real-time performance and stability of current regulation. Especially with the widespread adoption of digital control architectures, current regulation not only needs to ensure steady-state accuracy but also needs to have agile response capabilities to rapid changes in electrical quantities in order to adapt to the operational needs under complex load conditions.

[0003] Existing current regulation technologies generally employ proportional-integral (PI) controllers with fixed parameters. While these controllers perform well under steady-state or slowly changing load conditions, they exhibit significant limitations when power loads change abruptly. Specifically, when a high-power load is suddenly applied or removed, the DC-side voltage may experience a momentary drop or surge. Due to the reliance on error feedback accumulation, the PI controller's response inherently exhibits hysteresis, failing to quickly compensate for the power deficit. This hysteresis leads to slow adjustment of the inner current loop, and the DC voltage recovery process is accompanied by overshoot and oscillation. This not only affects the output voltage quality but may also trigger system protection actions or even device overstress. Furthermore, simply increasing the controller bandwidth to improve response speed amplifies the effects of switching noise and model mismatch, jeopardizing stability. Therefore, how to quickly stabilize the DC-side current when the rectifier experiences sudden power load changes has become a challenging problem for the industry. Summary of the Invention

[0004] This application provides a rectifier current regulation system and method based on digital control, which can quickly stabilize the DC side current when the rectifier power load changes abruptly.

[0005] In a first aspect, this application provides a rectifier current regulation method based on digital control. The rectifier current regulation method includes the following steps: monitoring the output voltage signal on the DC side of the rectifier, and extracting the gradient change characteristics of the output voltage error from the output voltage signal; when the output voltage error on the DC side of the rectifier exceeds a preset voltage error threshold, immediately triggering a control interruption, thereby determining the event trigger point when the rectifier power load changes abruptly; performing a voltage drop trend analysis on the output voltage in the next current inner loop control cycle based on the gradient change characteristics and the transient response characteristics of the rectifier at the event trigger point, thereby obtaining the voltage drop trend in the next current inner loop control cycle; performing feedforward compensation on the output current of the rectifier at the beginning of the next current inner loop control cycle based on the voltage drop trend and the load active power of the rectifier at the event trigger point, thereby obtaining the feedforward current compensation amount of the rectifier at the beginning of the next current inner loop control cycle; generating a feedforward current compensation command based on the feedforward current compensation amount, and then adjusting the output current of the rectifier at the beginning of the next current inner loop control cycle based on the feedforward current compensation command.

[0006] In this embodiment, extracting the gradient change features of the output voltage error from the output voltage signal specifically includes: determining the output voltage error sequence based on the output voltage signal and the reference voltage; performing gradient analysis on the output voltage error sequence to obtain the gradient change features of the output voltage error.

[0007] In this embodiment, determining the event trigger point when the rectifier power load changes abruptly specifically includes: recording the trigger time of the control interrupt when a control interrupt is triggered; and marking the trigger time of the control interrupt as the event trigger point when the rectifier power load changes abruptly.

[0008] In this embodiment, the voltage drop trend analysis of the output voltage in the next current inner loop control cycle is performed using the gradient change characteristics and the transient response characteristics of the rectifier at the event trigger point. Specifically, this includes: determining the transient response characteristics of the rectifier at the event trigger point; determining the equivalent load impedance of the rectifier at the event trigger point based on the output voltage and output current values; determining the characteristic response mode of the output voltage in the next current inner loop control cycle using the transient response characteristics and the equivalent load impedance; and predicting the voltage drop trend of the output voltage in the next current inner loop control cycle based on the characteristic response mode and the gradient change characteristics.

[0009] In this embodiment, the feedforward compensation of the rectifier's output current at the start of the next current inner loop control cycle is obtained by using the voltage drop trend and the rectifier's load active power at the event trigger point to obtain the feedforward current compensation amount of the rectifier at the start of the next current inner loop control cycle. Specifically, this includes: determining the rectifier's load active power at the event trigger point; determining the active power deficit required for the rectifier to maintain voltage stability at the event trigger point; determining the feedforward compensation strength of the rectifier's output current at the start of the next current inner loop control cycle based on the voltage drop trend; determining the reference feedforward current compensation amount of the rectifier's output current at the start of the next current inner loop control cycle based on the active power deficit and the feedforward compensation strength; and applying a safety boundary constraint to the reference feedforward current compensation amount using the load active power to obtain the feedforward current compensation amount of the rectifier at the start of the next current inner loop control cycle.

[0010] In this embodiment, generating a feedforward current compensation command based on the feedforward current compensation amount specifically includes: converting the feedforward current compensation amount into a feedforward current compensation signal; and generating a feedforward current compensation command based on the feedforward current compensation signal.

[0011] In this embodiment, adjusting the output current of the rectifier at the start of the next current inner loop control cycle by means of the feedforward current compensation command specifically includes: converting the feedforward current compensation command into a drive signal for the power switching device; controlling the conduction state of the power switching device by means of the drive signal; and adjusting the output current of the rectifier at the start of the next current inner loop control cycle according to the conduction state of the power switching device.

[0012] In this embodiment, the voltage drop trend represents the curve trend of the output voltage drop within the next current inner loop control cycle.

[0013] In this embodiment, the feedforward current compensation amount represents the current value used to compensate for the expected voltage drop in the next current inner loop control cycle.

[0014] Secondly, this application provides a rectifier current regulation system based on digital control, used to execute a rectifier current regulation method based on digital control. The rectifier current regulation system includes: a feature extraction module, used to monitor the output voltage signal on the DC side of the rectifier and extract the gradient change features of the output voltage error from the output voltage signal; a load change judgment module, used to immediately trigger a control interruption when the output voltage error on the DC side of the rectifier exceeds a preset voltage error threshold, thereby determining the event trigger point when the rectifier power load changes abruptly; and a drop trend analysis module, used to analyze the gradient change features and the transient response of the rectifier at the event trigger point. The response characteristics are used to analyze the voltage drop trend of the output voltage in the next current inner loop control cycle to obtain the voltage drop trend in the next current inner loop control cycle. The feedforward compensation module is used to perform feedforward compensation on the output current of the rectifier at the beginning of the next current inner loop control cycle based on the voltage drop trend and the load active power of the rectifier at the event trigger point to obtain the feedforward current compensation amount of the rectifier at the beginning of the next current inner loop control cycle. The current regulation module is used to generate a feedforward current compensation command based on the feedforward current compensation amount, and then adjust the output current of the rectifier at the beginning of the next current inner loop control cycle through the feedforward current compensation command.

[0015] The technical solution provided by the embodiments disclosed in this application has the following beneficial effects: Monitoring the output voltage signal on the DC side of the rectifier, and extracting the gradient change characteristics of the output voltage error from the output voltage signal; when the output voltage error on the DC side of the rectifier exceeds a preset voltage error threshold, immediately triggering a control interruption, thereby determining the event trigger point when the rectifier power load changes abruptly; analyzing the voltage drop trend of the output voltage in the next current inner loop control cycle using the gradient change characteristics and the transient response characteristics of the rectifier at the event trigger point, obtaining the voltage drop trend in the next current inner loop control cycle; using the voltage drop trend and the load active power of the rectifier at the event trigger point to perform feedforward compensation on the output current of the rectifier at the beginning of the next current inner loop control cycle, obtaining the feedforward current compensation amount of the rectifier at the beginning of the next current inner loop control cycle; generating a feedforward current compensation command based on the feedforward current compensation amount, and then adjusting the output current of the rectifier at the beginning of the next current inner loop control cycle using the feedforward current compensation command.

[0016] Therefore, in this application, the output current of the rectifier at the beginning of the next current inner loop control cycle can be adjusted by the feedforward current compensation command. Firstly, by extracting the gradient change characteristics of the voltage error from the DC-side voltage signal, the rapid change trend of electrical quantities can be captured before the voltage deviation accumulates, overcoming the inherent defect of traditional proportional-integral control that relies on error accumulation and has a slow response. Furthermore, when the voltage error exceeds a threshold, a control interruption is immediately triggered and the event trigger point is identified, enabling the rectifier to switch to a fast regulation mode at the initial moment of a load change, shortening the detection-response link and improving the transient sensitivity to sudden power increases or decreases. Subsequently, by combining the gradient change characteristics with the transient response characteristics of the rectifier at the event trigger point, the voltage drop trend in the next current inner loop cycle is further... By performing advance prediction, a short-term forward-looking model of future disturbances is constructed, enabling the rectifier to actively judge the future direction of change instead of passively waiting for errors to occur. Based on this, the feedforward current compensation is calculated by combining the rectifier's active power at the event trigger point, allowing the output current to jump to a target level that better meets the load requirements before the start of the next inner loop cycle. Through this synergistic mechanism of "disturbance prediction + power correlation compensation," the lag, overshoot, and oscillation generated by traditional feedback control under strong disturbance conditions are effectively eliminated. Finally, the current output of the next cycle is directly adjusted through the feedforward current compensation command, enabling the rectifier to achieve rapid current stabilization within the current inner loop control cycle after a load change, avoiding a large drop or surge in DC voltage, and fundamentally improving the stability of the rectifier under sudden power change scenarios.

[0017] In summary, the technical solution adopted in this application can quickly stabilize the DC side current when the rectifier power load changes abruptly. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only for this embodiment of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1 is an exemplary flowchart of a rectifier current regulation method based on digital control according to the present application; Figure 2 is a schematic flowchart of determining voltage drop trend according to the present application; Figure 3 is a schematic flowchart of determining feedforward current compensation amount according to the present application; Figure 4 is a block structure diagram of a rectifier current regulation system based on digital control according to the present application. Detailed Implementation

[0020] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this application.

[0021] This application provides a rectifier current regulation system and method based on digital control. The core of the system is to monitor the output voltage signal on the DC side of the rectifier and extract the gradient change characteristics of the output voltage error from the signal. When the output voltage error on the DC side of the rectifier exceeds a preset voltage error threshold, a control interruption is immediately triggered to determine the event trigger point when the rectifier power load changes abruptly. The system analyzes the voltage drop trend in the next current inner loop control cycle using the gradient change characteristics and the transient response characteristics of the rectifier at the event trigger point to obtain the voltage drop trend in the next current inner loop control cycle. The system uses the voltage drop trend and the load active power of the rectifier at the event trigger point to perform feedforward compensation on the output current of the rectifier at the beginning of the next current inner loop control cycle to obtain the feedforward current compensation amount at the beginning of the next current inner loop control cycle. A feedforward current compensation command is generated based on the feedforward current compensation amount, and the output current of the rectifier at the beginning of the next current inner loop control cycle is adjusted using the feedforward current compensation command.

[0022] Example 1: To better understand the above technical solution, the following will describe the above technical solution in detail with reference to the accompanying drawings and specific implementation methods. Referring to Figure 1, this figure is an exemplary flowchart of a rectifier current regulation method based on digital control according to this embodiment of the application. The rectifier current regulation method includes the following steps: In step S1, the output voltage signal on the DC side of the rectifier is monitored, and the gradient change characteristics of the output voltage error are extracted from the output voltage signal.

[0023] In practice, the output voltage of the rectifier's DC bus is monitored by a voltage sensor, and the analog signal output by the voltage sensor is used as the output voltage signal of the rectifier's DC side.

[0024] It should be noted that the output voltage signal mentioned in this application refers to a signal that reflects the output voltage state of the DC side of the rectifier.

[0025] In this embodiment, the gradient change characteristics of the output voltage error can be extracted from the output voltage signal by the following steps: determining the output voltage error sequence based on the output voltage signal and the reference voltage; performing gradient analysis on the output voltage error sequence to obtain the gradient change characteristics of the output voltage error.

[0026] It should be noted that the output voltage error sequence mentioned in this application represents the error sequence between the output voltage and the reference voltage, and the gradient change feature represents the feature describing the rate of change of the output voltage error.

[0027] In specific implementation, the output voltage error sequence can be determined based on the output voltage signal and the reference voltage in the following manner: the analog-to-digital converter module of the digital signal processor periodically samples the output voltage signal at a fixed control period to obtain discrete digital voltage values; simultaneously, a preset digital reference voltage value is read from the non-volatile memory of the digital signal processor; within each control period, the arithmetic logic unit of the digital signal processor performs a subtraction operation, subtracting the sampled digital voltage value from the digital reference voltage value, and calculates a voltage error value in real time; the digital signal processor stores this voltage error value in chronological order into a circular array of length N in its internal RAM, and the continuous voltage error values ​​stored in this array in chronological order constitute the output voltage error sequence.

[0028] In specific implementation, gradient analysis is performed on the output voltage error sequence to obtain the gradient change characteristics of the output voltage error. This can be achieved in the following way: The digital signal processor reads the voltage error values ​​of the current control cycle and the previous control cycle from the output voltage error sequence, and then performs a first-order backward differential operation, that is, subtracts the error value of the previous control cycle from the error value of the current control cycle, and then divides the difference by the duration of the control cycle to obtain the instantaneous rate of change of the output voltage error; the obtained instantaneous rate of change is used as the gradient change characteristics of the output voltage error.

[0029] In step S2, when the output voltage error on the DC side of the rectifier exceeds the preset voltage error threshold, a control interruption is immediately triggered, thereby determining the event trigger point when the rectifier power load changes abruptly.

[0030] It should be noted that the voltage error threshold mentioned in this application can be preset in the following way: obtain the maximum allowable voltage deviation of the rectifier under different typical load steps, and take 80% of the average of all maximum allowable voltage deviations as the voltage error threshold.

[0031] In specific implementation, firstly, a voltage error threshold comparison interrupt is configured in the interrupt controller of the digital signal processor to compare the absolute value of the output voltage error on the DC side of the rectifier with a preset voltage error threshold; when the absolute value of the error exceeds the voltage error threshold, the hardware comparison circuit automatically generates a high-priority interrupt request signal, which triggers the processor kernel to immediately suspend the current task and jump to execute the corresponding interrupt service routine.

[0032] In this embodiment, the event trigger point when the rectifier power load changes abruptly can be determined by the following steps: when a control interrupt is triggered, the trigger time of the control interrupt is recorded; the trigger time of the control interrupt is marked as the event trigger point when the rectifier power load changes abruptly.

[0033] It should be noted that the event trigger point described in this application identifies the moment when the rectifier power load changes abruptly.

[0034] In practice, firstly, in the interrupt service routine, the processor records the timestamp of the interrupt trigger moment, and saves the DC side output voltage value, output current value and gradient change characteristics at that moment. Secondly, the moment is marked as the event trigger point when the rectifier power load changes abruptly.

[0035] In step S3, the voltage drop trend in the next current inner loop control cycle is analyzed by using the gradient change characteristics and the transient response characteristics of the rectifier at the event trigger point, so as to obtain the voltage drop trend in the next current inner loop control cycle.

[0036] Preferably, in this embodiment, the voltage drop trend of the output voltage in the next current inner loop control cycle is analyzed by the gradient change characteristics and the transient response characteristics of the rectifier at the event trigger point, and the voltage drop trend in the next current inner loop control cycle is obtained. Referring to Figure 2, which is a flowchart of determining the voltage drop trend in some embodiments of this application, the voltage drop trend can be determined by the following steps in this embodiment: determining the transient response characteristics of the rectifier at the event trigger point; determining the equivalent load impedance of the rectifier at the event trigger point based on the output voltage and output current values ​​of the rectifier at the event trigger point; determining the characteristic response mode of the output voltage in the next current inner loop control cycle based on the transient response characteristics and the equivalent load impedance; predicting the voltage drop trend of the output voltage in the next current inner loop control cycle based on the characteristic response mode and the gradient change characteristics, and obtaining the voltage drop trend in the next current inner loop control cycle.

[0037] It should be noted that the transient response characteristics described in this application represent the dynamic response behavior of the rectifier when the load changes abruptly; the equivalent load impedance represents the degree of influence of the load on the rectifier's output current and output voltage; the characteristic response mode represents the expected response mode of the rectifier's output voltage in the next current inner loop control cycle; and the voltage drop trend represents the curve trend of the output voltage drop in the next current inner loop control cycle.

[0038] In specific implementation, the transient response characteristics of the rectifier at the event trigger point can be determined in the following way: read the rectifier system parameters obtained in advance through system identification from the non-volatile memory of the digital signal processor, including the output filter capacitor value, the equivalent series resistance value, and the system control bandwidth; establish a second-order system state-space model of the rectifier based on the system parameters; extract the overshoot and damping coefficient of the rectifier by solving the time-domain response characteristics of the model under a unit step input; and use these extracted parameters as the transient response characteristics of the rectifier at the event trigger point.

[0039] In practice, the equivalent load impedance of the rectifier at the event trigger point can be determined by the following method based on the output voltage and output current values ​​of the rectifier at the event trigger point: at the event trigger point, the output voltage value of the DC side of the rectifier is divided by the synchronously acquired output current value by the floating-point arithmetic unit of the digital signal processor, and the value obtained by division is used as the equivalent load impedance of the rectifier at the event trigger point.

[0040] In specific implementation, determining the characteristic response mode of the output voltage in the next current inner loop control cycle based on the transient response characteristics and the equivalent load impedance can be achieved in the following way: Substitute the equivalent load impedance as a load boundary condition into the second-order system state-space model of the rectifier, solve the characteristic equation of the second-order system state-space model using the Jacobi iterative method to obtain the pole distribution and oscillation frequency of the rectifier, and use the damping coefficient in the transient response characteristics as a weighting factor to perform modal correction on the obtained pole distribution using the weighted least squares method; simultaneously, utilize the overshoot parameter in the transient response characteristics to perform amplitude constraint correction on the initial oscillation frequency using the pole placement algorithm; and use the pole distribution and oscillation frequency after correction by the damping coefficient and overshoot parameter as the characteristic response mode of the output voltage in the next current inner loop control cycle.

[0041] In specific implementation, the voltage drop trend prediction for the output voltage in the next current inner loop control cycle is obtained based on the characteristic response mode and the gradient change characteristics. This voltage drop trend can be achieved in the following way: using the gradient change characteristics as the initial disturbance rate, and combining the pole distribution and oscillation frequency in the characteristic response mode, a time-domain prediction function for the output voltage is constructed using the state-space reconstruction method; a fourth-order Runge-Kutta numerical integration algorithm is used to iteratively solve the prediction function in the next control cycle with microsecond-level steps to obtain the instantaneous value sequence of the output voltage; then, a least-squares polynomial curve fitting algorithm is used to fit the instantaneous value sequence, and the trend of the fitted curve is taken as the voltage drop trend in the next current inner loop control cycle.

[0042] In step S4, the output current of the rectifier at the beginning of the next current inner loop control cycle is fed forward by the voltage drop trend and the load active power of the rectifier at the event trigger point, so as to obtain the feedforward current compensation amount of the rectifier at the beginning of the next current inner loop control cycle.

[0043] Preferably, in this embodiment, the output current of the rectifier at the beginning of the next current inner loop control cycle is feedforward compensated based on the voltage drop trend and the load active power of the rectifier at the event trigger point, to obtain the feedforward current compensation amount of the rectifier at the beginning of the next current inner loop control cycle. Referring to Figure 3, which is a flowchart illustrating the determination of the feedforward current compensation amount in some embodiments of this application, the determination of the feedforward current compensation amount in this embodiment can be achieved by the following steps: determining the load active power of the rectifier at the event trigger point; determining the active power deficit required for the rectifier to maintain voltage stability at the event trigger point; determining the feedforward compensation strength of the output current of the rectifier at the beginning of the next current inner loop control cycle based on the voltage drop trend; determining the reference feedforward current compensation amount of the output current of the rectifier at the beginning of the next current inner loop control cycle based on the active power deficit and the feedforward compensation strength; and applying a safety boundary constraint to the reference feedforward current compensation amount based on the load active power to obtain the feedforward current compensation amount of the rectifier at the beginning of the next current inner loop control cycle.

[0044] It should be noted that, in this application, the load active power refers to the active power provided by the rectifier to the load at the event trigger point; the active power deficit refers to the amount of additional active power required by the rectifier to maintain voltage stability at the event trigger point; the feedforward compensation strength refers to the parameter controlling the feedforward compensation intensity; the reference feedforward current compensation amount refers to the preliminary calculated value of the feedforward current compensation; and the feedforward current compensation amount refers to the current value used to compensate for the expected voltage drop in the next current inner loop control cycle.

[0045] In practice, the load active power of the rectifier at the event trigger point can be determined in the following way: obtain the output voltage and output current values ​​of the DC side of the rectifier at the event trigger point, and take the product between the output voltage and output current values ​​as the load active power of the rectifier at the event trigger point.

[0046] In practice, the active power deficit required for the rectifier to maintain voltage stability at the event trigger point can be determined as follows: extract the expected minimum voltage value from the voltage drop trend, subtract the square of the expected minimum voltage value from the square of the rated reference voltage, divide by the equivalent load impedance of the rectifier at the event trigger point, and take the value obtained by the division as the active power deficit required for the rectifier to maintain voltage stability at the event trigger point.

[0047] In specific implementation, the feedforward compensation strength of the rectifier's output current at the start of the next current inner loop control cycle can be determined based on the voltage drop trend in the following manner: First, the voltage drop trend is smoothed using a sliding window averaging algorithm to eliminate high-frequency noise interference; then, differential operations are applied to extract the voltage drop change rate at different positions from the voltage drop trend; the difference between the largest voltage drop change rate and all voltage drop change rates except the largest voltage drop change rate is summed; then, the summed value is divided by the smallest voltage drop change rate, and the value obtained by division is used as the feedforward compensation strength of the rectifier's output current at the start of the next current inner loop control cycle.

[0048] In specific implementation, the reference feedforward current compensation amount for the rectifier's output current at the start of the next current inner loop control cycle can be determined by the following method based on the active power deficit and the feedforward compensation strength: divide the active power deficit by the minimum voltage drop in the voltage drop trend to obtain the transition compensation current value; then multiply this transition compensation current value by the feedforward compensation strength coefficient, and use the value obtained by dividing by the product as the reference feedforward current compensation amount.

[0049] In specific implementation, the feedforward current compensation amount of the rectifier at the beginning of the next current inner loop control cycle can be obtained by constraining the reference feedforward current compensation amount with the load active power using a safety boundary. This can be achieved in the following way: First, calculate the maximum allowable output current value of the rectifier based on the load active power. Specifically, divide the load active power by the rated output voltage of the rectifier and then multiply by a preset safety factor. Then, compare the reference feedforward current compensation amount with the calculated maximum allowable output current value, and use a saturation limiting algorithm to limit the reference feedforward current compensation amount within the maximum allowable output current range. Finally, use the current compensation amount obtained after constraint processing as the feedforward current compensation amount of the rectifier at the beginning of the next current inner loop control cycle.

[0050] In step S5, a feedforward current compensation command is generated based on the feedforward current compensation amount, and then the output current of the rectifier is adjusted at the beginning of the next current inner loop control cycle through the feedforward current compensation command.

[0051] In this embodiment, generating a feedforward current compensation command based on the feedforward current compensation amount can be achieved by the following steps: converting the feedforward current compensation amount into a feedforward current compensation signal; and generating a feedforward current compensation command based on the feedforward current compensation signal.

[0052] It should be noted that the feedforward current compensation command described in this application refers to the control command to implement feedforward current compensation in the next current inner loop control cycle.

[0053] In a specific implementation, the feedforward current compensation amount can be converted into a feedforward current compensation signal in the following way: the feedforward current compensation amount is normalized by the digital gain module of the digital signal processor and converted into a digital signal that conforms to the input range of the current controller; at the same time, the signal is smoothed by a digital filtering algorithm to eliminate high-frequency components, and finally a standardized feedforward current compensation signal is generated.

[0054] In specific implementation, the feedforward current compensation instruction generated based on the feedforward current compensation signal can be achieved in the following way: The feedforward current compensation signal is input to the analog-to-digital converter sampling module of the controller, and converted into the corresponding pulse width modulation control parameters through a voltage-duty cycle conversion algorithm. This conversion process uses a linear scaling transformation method to map the voltage signal into a pulse width modulation duty cycle, and simultaneously combines the system clock signal for timing synchronization. The timer module of the digital signal processor generates a synchronization trigger signal at the beginning of the next current inner loop control cycle, and the complete instruction is output through the pulse width modulation output module. This instruction is then used as the feedforward current compensation instruction and output to the power drive circuit.

[0055] In this embodiment, adjusting the output current of the rectifier at the start of the next current inner loop control cycle by means of the feedforward current compensation command can be achieved by the following steps: converting the feedforward current compensation command into a drive signal for the power switching device; controlling the conduction state of the power switching device by means of the drive signal; and adjusting the output current of the rectifier at the start of the next current inner loop control cycle according to the conduction state of the power switching device.

[0056] In a specific implementation, the feedforward current compensation command can be converted into a drive signal for a power switching device in the following way: the feedforward current compensation command is level-shifted and amplified by a gate driver to generate a drive signal that meets the requirements of the power switching device.

[0057] In a specific implementation, the power switching device’s conduction state can be controlled by the drive signal in the following way: the processed drive signal is applied to the gate of the insulated gate bipolar transistor or the metal oxide semiconductor field-effect transistor, and the conduction and turn-off times of the power switching device are controlled by adjusting the gate voltage, thereby achieving precise control of the power switching device’s operating state.

[0058] In practice, adjusting the rectifier's output current at the start of the next current inner loop control cycle based on the conduction state of the power switching device can be achieved in the following way: the switching action of the power switching device changes the voltage waveform of the rectifier's AC input, and the current ripple is smoothed by the output filter inductor to obtain a precisely adjusted output current on the DC side. The magnitude and waveform of the output current are determined by the pulse width modulation duty cycle corresponding to the feedforward current compensation command, thereby achieving rapid adjustment of the output current at the start of the next current inner loop control cycle.

[0059] Therefore, in this application, the output current of the rectifier at the beginning of the next current inner loop control cycle can be adjusted by the feedforward current compensation command. Firstly, by extracting the gradient change characteristics of the voltage error from the DC-side voltage signal, the rapid change trend of electrical quantities can be captured before the voltage deviation accumulates, overcoming the inherent defect of traditional proportional-integral control that relies on error accumulation and has a slow response. Furthermore, when the voltage error exceeds a threshold, a control interruption is immediately triggered and the event trigger point is identified, enabling the rectifier to switch to a fast regulation mode at the initial moment of a load change, shortening the detection-response link and improving the transient sensitivity to sudden power increases or decreases. Subsequently, by combining the gradient change characteristics with the transient response characteristics of the rectifier at the event trigger point, the voltage drop trend in the next current inner loop cycle is further... By performing advance prediction, a short-term forward-looking model of future disturbances is constructed, enabling the rectifier to actively judge the future direction of change instead of passively waiting for errors to occur. Based on this, the feedforward current compensation is calculated by combining the rectifier's active power at the event trigger point, allowing the output current to jump to a target level that better meets the load requirements before the start of the next inner loop cycle. Through this synergistic mechanism of "disturbance prediction + power correlation compensation," the lag, overshoot, and oscillation generated by traditional feedback control under strong disturbance conditions are effectively eliminated. Finally, the current output of the next cycle is directly adjusted through the feedforward current compensation command, enabling the rectifier to achieve rapid current stabilization within the current inner loop control cycle after a load change, avoiding a large drop or surge in DC voltage, and fundamentally improving the stability of the rectifier under sudden power change scenarios.

[0060] In summary, the technical solution adopted in this application can quickly stabilize the DC side current when the rectifier power load changes abruptly.

[0061] Example 2: This application provides a rectifier current regulation system based on digital control. Referring to Figure 4, which is a module structure diagram of a rectifier current regulation system based on digital control according to this embodiment of the application, the rectifier current regulation system includes: a feature extraction module 100, used to monitor the output voltage signal on the DC side of the rectifier and extract the gradient change features of the output voltage error from the output voltage signal; a load change judgment module 200, used to immediately trigger a control interruption when the output voltage error on the DC side of the rectifier exceeds a preset voltage error threshold, thereby determining the event trigger point when the rectifier power load changes suddenly; and a drop trend analysis module 300, used to analyze the gradient change features and the rectifier current regulation system. The transient response characteristics of the rectifier at the event trigger point are used to analyze the voltage drop trend of the output voltage in the next current inner loop control cycle, and the voltage drop trend in the next current inner loop control cycle is obtained. The feedforward compensation module 400 is used to perform feedforward compensation on the output current of the rectifier at the beginning of the next current inner loop control cycle based on the voltage drop trend and the load active power of the rectifier at the event trigger point, and obtain the feedforward current compensation amount of the rectifier at the beginning of the next current inner loop control cycle. The current regulation module 500 is used to generate a feedforward current compensation command according to the feedforward current compensation amount, and then adjust the output current of the rectifier at the beginning of the next current inner loop control cycle through the feedforward current compensation command.

[0062] This application is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of this application. It will be understood that each block of the flowchart illustrations and / or block diagrams, as well as combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create means for implementing the functions specified in one or more blocks of the flowchart illustrations and / or one or more blocks of the block diagrams.

[0063] Those skilled in the art will understand that all or part of the steps in the various methods of the above embodiments can be implemented by a program instructing related hardware. The program can be stored in a computer-readable storage medium, including read-only memory (ROM), random access memory (RAM), programmable read-only memory (PROM), erasable programmable read-only memory (EPROM), one-time programmable read-only memory (OTPROM), electrically-Erasable Programmable Read-Only Memory (EEPROM), compactdisc read-only memory (CD-ROM) or other optical disc storage, disk storage, magnetic tape storage, or any other computer-readable medium capable of carrying or storing data.

[0064] It should also be noted that the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus. Unless otherwise specified, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes that element.

Claims

1. A rectifier current regulation method based on digital control, characterized in that, The rectifier current regulation method includes the following steps: monitoring the output voltage signal on the DC side of the rectifier, and extracting the gradient change characteristics of the output voltage error from the output voltage signal; when the output voltage error on the DC side of the rectifier exceeds a preset voltage error threshold, immediately triggering a control interruption, thereby determining the event trigger point when the rectifier power load changes abruptly; analyzing the voltage drop trend of the output voltage in the next current inner loop control cycle based on the gradient change characteristics and the transient response characteristics of the rectifier at the event trigger point, and obtaining the voltage drop trend in the next current inner loop control cycle; using the voltage drop trend and the load active power of the rectifier at the event trigger point to perform feedforward compensation on the output current of the rectifier at the beginning of the next current inner loop control cycle, and obtaining the feedforward current compensation amount of the rectifier at the beginning of the next current inner loop control cycle; generating a feedforward current compensation command based on the feedforward current compensation amount, and then adjusting the output current of the rectifier at the beginning of the next current inner loop control cycle through the feedforward current compensation command.

2. The rectifier current regulation method based on digital control as described in claim 1, characterized in that, Extracting the gradient change characteristics of the output voltage error from the output voltage signal specifically includes: determining the output voltage error sequence based on the output voltage signal and the reference voltage; performing gradient analysis on the output voltage error sequence to obtain the gradient change characteristics of the output voltage error.

3. The rectifier current regulation method based on digital control as described in claim 1, characterized in that, Determining the event trigger point when the rectifier power load changes abruptly includes: recording the trigger time of the control interrupt when it is triggered; and marking the trigger time of the control interrupt as the event trigger point when the rectifier power load changes abruptly.

4. The rectifier current regulation method based on digital control as described in claim 1, characterized in that, The voltage drop trend analysis of the output voltage in the next current inner loop control cycle is performed by analyzing the gradient change characteristics and the transient response characteristics of the rectifier at the event trigger point. Specifically, this includes: determining the transient response characteristics of the rectifier at the event trigger point; determining the equivalent load impedance of the rectifier at the event trigger point based on the output voltage and output current values; determining the characteristic response mode of the output voltage in the next current inner loop control cycle based on the transient response characteristics and the equivalent load impedance; and predicting the voltage drop trend of the output voltage in the next current inner loop control cycle based on the characteristic response mode and the gradient change characteristics.

5. The rectifier current regulation method based on digital control as described in claim 1, characterized in that, By using the voltage drop trend and the rectifier's load active power at the event trigger point to perform feedforward compensation on the rectifier's output current at the start of the next current inner loop control cycle, the feedforward current compensation amount of the rectifier at the start of the next current inner loop control cycle is obtained. Specifically, this includes: determining the rectifier's load active power at the event trigger point; determining the active power deficit required for the rectifier to maintain voltage stability at the event trigger point; determining the feedforward compensation strength of the rectifier's output current at the start of the next current inner loop control cycle based on the voltage drop trend; determining the reference feedforward current compensation amount of the rectifier's output current at the start of the next current inner loop control cycle based on the active power deficit and the feedforward compensation strength; and applying a safety boundary constraint to the reference feedforward current compensation amount using the load active power to obtain the feedforward current compensation amount of the rectifier at the start of the next current inner loop control cycle.

6. The rectifier current regulation method based on digital control as described in claim 1, characterized in that, Generating a feedforward current compensation command based on the feedforward current compensation amount specifically includes: converting the feedforward current compensation amount into a feedforward current compensation signal; and generating a feedforward current compensation command based on the feedforward current compensation signal.

7. The rectifier current regulation method based on digital control as described in claim 1, characterized in that, Adjusting the rectifier's output current at the start of the next current inner loop control cycle by means of the feedforward current compensation command specifically includes: converting the feedforward current compensation command into a drive signal for the power switching device; controlling the conduction state of the power switching device by the drive signal; and adjusting the rectifier's output current at the start of the next current inner loop control cycle according to the conduction state of the power switching device.

8. The rectifier current regulation method based on digital control as described in claim 1, characterized in that, The voltage drop trend indicates the curve trend of the output voltage drop within the next current inner loop control cycle.

9. The rectifier current regulation method based on digital control as described in claim 1, characterized in that, The feedforward current compensation amount represents the current value used to compensate for the expected voltage drop during the next current inner loop control cycle.

10. A rectifier current regulation system based on digital control, used to execute a rectifier current regulation method based on digital control as described in any one of claims 1 to 9, characterized in that, The rectifier current control system includes: a feature extraction module for monitoring the output voltage signal on the DC side of the rectifier and extracting the gradient change features of the output voltage error from the output voltage signal; a load change judgment module for immediately triggering a control interruption when the output voltage error on the DC side of the rectifier exceeds a preset voltage error threshold, thereby determining the event trigger point when the rectifier power load changes abruptly; a voltage drop trend analysis module for performing voltage drop trend analysis on the output voltage in the next current inner loop control cycle based on the gradient change features and the transient response characteristics of the rectifier at the event trigger point, thereby obtaining the voltage drop trend in the next current inner loop control cycle; a feedforward compensation module for performing feedforward compensation on the output current of the rectifier at the beginning of the next current inner loop control cycle based on the voltage drop trend and the active power of the rectifier load at the event trigger point, thereby obtaining the feedforward current compensation amount of the rectifier at the beginning of the next current inner loop control cycle; and a current adjustment module for generating a feedforward current compensation command based on the feedforward current compensation amount, thereby adjusting the output current of the rectifier at the beginning of the next current inner loop control cycle based on the feedforward current compensation command.

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