Control method and device of multi-module parallel operation system, converter module and multi-module parallel operation system

Abstract

The invention provides a control method and device of a multi-module parallel operation system, a converter module and the multi-module parallel operation system. The method comprises the following steps: detecting the working condition of the converter module; if the converter module is in the dynamic working condition, acquiring a current-sharing ring output value of the converter module in the current control period, and extracting a symbol of the current-sharing ring output value; adjusting the polarity of a preset compensation value by adopting the symbol of the current sharing ring output value, and compensating a voltage given value of the converter module through the adjusted preset compensation value; and generating a corresponding PWM (Pulse Width Modulation) signal based on the compensated given voltage value so as to drive a switching tube in the converter module. According to the method, the preset compensation value adjusted through the output value symbol of the current-sharing ring can be directly superposed to the voltage given value, so that the generation and response time of the compensation signal is greatly shortened, the rapid expansion of the current deviation is effectively suppressed, and the response speed of the current-sharing ring under the dynamic working condition is remarkably improved.

Description

Technical Field

[0001] This invention relates to the field of multi-machine parallel system technology, and in particular to a control method, device, converter module and multi-module parallel system for a multi-module parallel system. Background Technology

[0002] In fields such as new energy power generation, industrial power conversion, and distributed power supply, multi-module parallel systems have become the mainstream architecture for meeting the demands of high-power, high-stability power consumption due to their core advantages such as flexible expansion, strong redundancy, and high power supply reliability. One of the core control objectives of multi-module parallel systems is to achieve current balancing (i.e., current sharing) among the modules. The effectiveness of current sharing directly determines the system's operating efficiency, circulating current loss, and module lifespan. Therefore, current sharing control technology is a key support for the stable operation of multi-module parallel systems.

[0003] To achieve current sharing control, current sharing loop control schemes are commonly used in existing technologies. However, in practical applications, when the system faces dynamic conditions such as sudden loading and unloading, the response of existing current sharing loop control schemes is slow, which leads to a rapid increase in the current deviation between modules, thereby affecting the dynamic stability and power supply quality of the system. Summary of the Invention

[0004] This invention provides a control method, device, converter module, and multi-module parallel system for solving the problem of poor current sharing effect in existing multi-machine parallel systems when suddenly adding or removing loads.

[0005] In a first aspect, embodiments of the present invention provide a control method for a multi-module parallel system, applied to any converter module of the multi-module parallel system, comprising: The operating condition of the converter module is detected; the operating condition includes dynamic operating condition and steady-state operating condition; If the converter module is in a dynamic operating condition, the current sharing loop output value of the converter module in the current control cycle is obtained, and the sign of the current sharing loop output value is extracted. The polarity of the preset compensation value is adjusted by using the sign of the current sharing ring output value, and the voltage setpoint of the converter module is compensated by the adjusted preset compensation value. Based on the compensated voltage setpoint, a corresponding PWM signal is generated to drive the switching transistors in the converter module.

[0006] In one possible implementation, the dynamic operating conditions include sudden load increase and sudden load decrease conditions; the preset compensation value includes a first preset compensation value and a second preset compensation value. The step of adjusting the polarity of the preset compensation value using the sign of the current sharing loop output value includes: If the converter module is under sudden load conditions, the polarity of the first preset compensation value is adjusted by using the sign of the current sharing loop output value; If the converter module is in a sudden load unloading condition, the polarity of the second preset compensation value is adjusted by the sign of the current sharing ring output value; wherein, the first preset compensation value is not equal to the second preset compensation value.

[0007] In one possible implementation, adjusting the polarity of the preset compensation value using the sign of the current sharing loop output value includes: Multiply the sign of the current equalization ring output value by the preset compensation value to obtain the adjusted preset compensation value.

[0008] In one possible implementation, before adjusting the polarity of the preset compensation value using the sign of the current sharing loop output value, the method further includes: Obtain the absolute value of the rate of change of the load rate of the converter module; The preset compensation value is determined based on the absolute value of the rate of change; and the absolute value of the rate of change is positively correlated with the preset compensation value.

[0009] In one possible implementation, detecting the operating condition of the converter module includes: Obtain the load rate of the converter module; If the rate of change of the load rate is greater than a first preset threshold, the converter module is determined to have entered a sudden load condition; the first preset threshold is greater than zero. If the rate of change of the load rate is less than the second preset threshold, the converter module is determined to enter the sudden load unloading condition; the second preset threshold is less than zero.

[0010] In one possible implementation, if the converter module is in a dynamic operating condition, then the current sharing loop output value of the converter module in the current control cycle is obtained, and the sign of the current sharing loop output value is extracted, including: If the converter module is in a dynamic operating condition, the current sharing loop output value of the converter module in the current control cycle is obtained, and the sign of the current sharing loop output value is extracted and latched in the current communication cycle. Accordingly, the step of adjusting the polarity of the preset compensation value by using the sign of the current sharing loop output value, and compensating the voltage setpoint of the converter module by using the adjusted preset compensation value, includes: Within the current communication cycle, the polarity of the preset compensation value is adjusted by using the sign of the current sharing loop output value, and the voltage setpoint of the converter module is compensated by the adjusted preset compensation value.

[0011] In one possible implementation, obtaining the current sharing loop output value of the converter module in the current control cycle includes: Obtain the average current of the multi-module parallel system in the current control cycle; The difference between the actual output current of the converter module and the average current is used to obtain the current sharing difference value. The current sharing difference is input into the PI controller to obtain the output value of the current sharing loop.

[0012] In one possible implementation, after detecting the operating condition of the converter module, the method further includes: If the converter module is in steady-state operation, then calculate the current sharing loop output value of the converter module in the current control cycle; The voltage setpoint of the converter module is compensated by the output value of the current sharing loop in the current control cycle.

[0013] Secondly, embodiments of the present invention provide a control device for a multi-module parallel system, comprising: The operating condition detection module is used to detect the operating condition of the converter module; the operating condition includes dynamic operating condition and steady-state operating condition. The symbol extraction module is used to obtain the current sharing loop output value of the converter module in the current control cycle and extract the symbol of the current sharing loop output value if the converter module is in a dynamic operating condition. The voltage compensation module is used to adjust the polarity of the preset compensation value by using the sign of the current sharing ring output value, and to compensate the voltage setpoint of the converter module by using the adjusted preset compensation value. The control module is used to generate a corresponding PWM signal based on the compensated voltage setpoint to drive the switching transistors in the converter module.

[0014] Thirdly, embodiments of the present invention provide a converter module, including a controller and a switching network; the switching network includes switching transistors; the controller includes a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the computer program to implement the steps of the control method for the multi-module parallel system as described in any possible implementation of the first aspect above.

[0015] Fourthly, embodiments of the present invention provide a multi-module parallel system, which includes the converter module described in the third aspect above.

[0016] This invention provides a control method, device, converter module, and multi-module parallel system for a multi-module parallel operation system. The method first detects the operating condition of the converter module to avoid unnecessary dynamic compensation intervention under steady-state conditions. If the converter module is in a dynamic operating condition, the current sharing loop output value of the converter module in the current control cycle is obtained, and the sign of the current sharing loop output value is extracted. This ensures that the sign accurately reflects the deviation direction of the module current relative to the system average current after a sudden load change, without relying on complete closed-loop deviation accumulation and complex calculations. The polarity of a preset compensation value is adjusted using the sign of the current sharing loop output value, and the adjusted preset compensation value is used to... The voltage setpoint of the converter module is compensated, ensuring that the compensation direction perfectly matches the current deviation correction requirements and avoiding reverse compensation from exacerbating current imbalance. Simultaneously, the preset compensation value does not require real-time calculation and can be directly superimposed on the voltage setpoint, significantly shortening the generation and response time of the compensation signal. This allows the converter module to quickly output targeted compensation during sudden load changes, effectively suppressing the rapid expansion of current deviation. Finally, a corresponding PWM signal is generated based on the compensated voltage setpoint to drive the switching transistors in the converter module, significantly improving the current sharing loop response speed under dynamic operating conditions, reducing inter-module circulating current losses, and enhancing the dynamic stability and power supply quality of the multi-module parallel system. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments of the present invention, 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 some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 This is a schematic diagram of the conventional control loop of the control method for the multi-module parallel system provided in the embodiments of the present invention; Figure 2 This is a flowchart illustrating the implementation of the control method for a multi-module parallel system provided in an embodiment of the present invention. Figure 3 This is a schematic diagram of the structure of the control device for the multi-module parallel system provided in an embodiment of the present invention; Figure 4 This is a schematic diagram of the controller provided in an embodiment of the present invention. Detailed Implementation

[0019] In the following description, specific details such as particular system architectures and techniques are set forth for illustrative purposes and not for limitation, in order to provide a thorough understanding of the embodiments of the invention. However, those skilled in the art will understand that the invention can be implemented in other embodiments without these specific details. In other instances, detailed descriptions of well-known systems, apparatuses, circuits, and methods are omitted so as not to obscure the description of the invention with unnecessary detail.

[0020] To make the objectives, technical solutions, and advantages of the present invention clearer, specific embodiments will be described below in conjunction with the accompanying drawings.

[0021] To achieve flow sharing control, flow sharing loop control schemes are commonly used in related technologies, and their core logic is referenced from... Figure 1 , Figure 1 A schematic diagram of the control loop of a conventional multi-module parallel system is shown. This control loop includes a current sharing loop, a voltage loop, and a current loop. The current sharing loop collects the output current I of each converter module in real time. out_fdb Calculate the output current I of a single converter module. out_fdb Average output current I of all parallel converter modules avg The difference is used to generate a current sharing loop output value through closed-loop adjustment, which is then added as a compensation to the voltage loop setpoint V of the corresponding module. out_ref Then it enters the voltage loop and current loop, ultimately achieving current balance among the modules.

[0022] However, in practical applications, the limitations of existing current sharing loop control schemes become particularly prominent when the system faces dynamic conditions such as sudden loading and unloading. Under dynamic conditions, the load current or power changes drastically, causing the current deviation between each converter module to expand rapidly. Existing current sharing loops rely on a closed-loop response logic of "real-time detection of current deviation - calculation of compensation - voltage adjustment." This process suffers from detection lag and calculation lag, making it impossible for the compensation to keep up with the dynamically changing current deviation in a timely manner. This limits the adjustment capability of the current sharing loop and makes it difficult to quickly smooth out the current imbalance between modules, thus affecting the dynamic stability and power supply quality of the system. Therefore, how to improve the response speed of the current sharing loop in multi-module parallel systems under dynamic conditions such as sudden loading and unloading, and solve the problem of poor dynamic current sharing effect, has become an urgent technical problem to be solved in this field.

[0023] To address the aforementioned issues, this embodiment provides a control method for a multi-module parallel system, applicable to any converter module of the multi-module parallel system. (See [link]). Figure 2 The diagram illustrates the implementation flowchart of the control method for a multi-module parallel system provided in an embodiment of the present invention, which is described in detail below: S101: Detect the operating condition of the converter module; the operating condition includes dynamic operating condition and steady-state operating condition.

[0024] In this embodiment, the converter module may include a rectifier and an inverter. Dynamic operating condition refers to an operating condition where the load demand of the converter module changes rapidly, typically a sudden load increase or decrease; steady-state operating condition refers to an operating condition where the load demand of the converter module remains stable, and the output current and voltage fluctuations are within allowable ranges. The controller first determines the operating condition of the converter module to ascertain whether it is in a dynamic or steady-state condition at the current moment, providing a basis for subsequent control mode switching.

[0025] In one possible embodiment, the controller can acquire the output electrical signal of the converter module and determine the operating condition of the converter module based on the rate of change of the output electrical signal.

[0026] Specifically, the output electrical signal can include output voltage, output current, and output power.

[0027] When the output electrical signal is the output current, the controller can collect the output current of the converter module in real time. When the absolute value of the rate of change of the output current is greater than the first preset rate of change threshold, the converter module is determined to be in dynamic operating condition. When the absolute value of the rate of change of the output current is not greater than the first preset rate of change threshold, the converter module is determined to be in steady-state operating condition.

[0028] When the output electrical signal is the output voltage, the controller can collect the output voltage of the converter module in real time. When the absolute value of the rate of change of the output voltage is greater than the second preset rate of change threshold, the converter module is determined to be in dynamic operating condition. When the absolute value of the rate of change of the output voltage is not greater than the second preset rate of change threshold, the converter module is determined to be in steady-state operating condition.

[0029] Specifically, when calculating the rate of change of the output electrical signal, the controller can calculate the rate of change of the output electrical signal at the current moment based on the output electrical signal at the current moment and the output electrical signal at the previous moment.

[0030] S102: If the converter module is in dynamic operating condition, then obtain the current sharing loop output value of the converter module in the current control cycle, and extract the sign of the current sharing loop output value.

[0031] In this embodiment, when the converter module is detected to be in a dynamic operating condition at the current moment, the controller switches the control strategy from the current sharing loop control strategy to the emergency control strategy. Under the emergency control strategy, the controller acquires and latches the current sharing loop output value for the current control cycle, and extracts the sign of the current sharing loop output value. This sign can be positive or negative. The current sharing loop output value is a control quantity calculated by the current sharing control loop based on the deviation between the converter module's output current and the average current of the multi-module parallel system, used to correct the voltage setpoint to achieve current sharing.

[0032] S103: Adjust the polarity of the preset compensation value by using the sign of the current sharing ring output value, and compensate the voltage setpoint of the converter module by using the adjusted preset compensation value.

[0033] In this embodiment, the preset compensation value is a fixed compensation parameter set in advance based on system parameters and actual experiments. This value can be fixed and does not require real-time calculation. It is used for rapid response under dynamic operating conditions, significantly shortening the generation and response time of the compensation signal. This allows the converter module to quickly output targeted compensation at the moment of load change, effectively suppressing the rapid expansion of current deviation. By extracting the sign of the current sharing loop output value, the correction direction of the current sharing loop can be determined, avoiding the problem of increased current deviation caused by incorrect compensation direction.

[0034] The voltage setpoint is the target reference value for the converter module's output voltage and is the core input for voltage loop control. By compensating the converter module's voltage setpoint with a preset compensation value, the magnitude of the voltage setpoint can be quickly corrected, accelerating the current sharing response speed.

[0035] S104: Generate a corresponding PWM (Pulse Width Modulation) signal based on the compensated voltage setpoint to drive the switching transistor in the converter module.

[0036] In this embodiment, voltage loop calculation is performed based on the compensated voltage setpoint, and a corresponding PWM signal is generated based on the voltage loop calculation result.

[0037] As can be seen from the above embodiments, this embodiment first detects the operating condition of the converter module to avoid unnecessary dynamic compensation intervention under steady-state conditions. If the converter module is in a dynamic operating condition, the current sharing loop output value of the converter module in the current control cycle is obtained, and the sign of the current sharing loop output value is extracted. This ensures that the sign accurately reflects the deviation direction of the module current relative to the system average current after a sudden load change, without relying on complete closed-loop deviation accumulation and complex calculations. The polarity of the preset compensation value is adjusted using the sign of the current sharing loop output value, and the voltage setpoint of the converter module is compensated by the adjusted preset compensation value. It ensures that the compensation direction perfectly matches the current deviation correction requirements, avoiding reverse compensation from exacerbating current imbalance. Simultaneously, the preset compensation value does not require real-time calculation and can be directly superimposed on the voltage setpoint, significantly shortening the generation and response time of the compensation signal. This allows the converter module to quickly output targeted compensation during sudden load changes, effectively suppressing the rapid expansion of current deviation. Finally, based on the compensated voltage setpoint, a corresponding PWM signal is generated to drive the switching transistors in the converter module, significantly improving the current sharing loop response speed under dynamic operating conditions, reducing inter-module circulating current losses, and enhancing the dynamic stability and power supply quality of multi-module parallel systems.

[0038] In one possible implementation, the dynamic operating conditions include sudden load increase and sudden load decrease conditions; the preset compensation value includes a first preset compensation value and a second preset compensation value. The specific implementation process of S103 includes: If the converter module is under sudden load conditions, the polarity of the first preset compensation value is adjusted by using the sign of the current sharing loop output value; If the converter module is in a sudden load unloading condition, the polarity of the second preset compensation value is adjusted by the sign of the current sharing ring output value; wherein, the first preset compensation value is not equal to the second preset compensation value.

[0039] Specifically, the sudden load increase condition is when the load current or power of the converter module rises rapidly in a short period of time, exceeding the load level during steady-state operation, resulting in a rapid increase in the current deviation between modules; the sudden load decrease condition is when the load current or power of the converter module drops rapidly in a short period of time, falling below the load level during steady-state operation, which may trigger reverse circulating current or current oscillation between modules.

[0040] As can be seen from the above embodiments, this embodiment further subdivides the dynamic operating conditions into sudden load increase conditions and sudden load decrease conditions, and sets a first preset compensation value and a second preset compensation value accordingly, so as to avoid the problem that a single compensation value is not adaptable to different dynamic operating conditions, and enable the control strategy to adapt to different load change scenarios.

[0041] In one possible implementation, the specific implementation process of adjusting the polarity of the preset compensation value using the sign of the current sharing ring output value in S103 includes: Multiply the sign of the current equalization ring output value by the preset compensation value to obtain the adjusted preset compensation value.

[0042] In this embodiment, under the condition of sudden load increase, the preset compensation value is M1. If the sign of the current sharing ring output value is positive, the adjusted preset compensation value is +M1; if the sign of the current sharing ring output value is negative, the adjusted preset compensation value is -M1. Under the condition of sudden load reduction, the preset compensation value is M2. If the sign of the current sharing ring output value is positive, the adjusted preset compensation value is +M2; if the sign of the current sharing ring output value is negative, the adjusted preset compensation value is -M2.

[0043] In one possible implementation, prior to S103, the method provided in this embodiment further includes: Obtain the absolute value of the rate of change of the load rate of the converter module; The preset compensation value is determined based on the absolute value of the rate of change; and the absolute value of the rate of change is positively correlated with the preset compensation value.

[0044] In this embodiment, the load rate is the ratio of the current output power of the converter module to its rated power, reflecting the load capacity of the converter module, and is usually expressed as a percentage. The load rate change rate is the ratio of the difference in load rate between two adjacent control cycles to the duration of the control cycle.

[0045] Specifically, the absolute value of the load rate change directly reflects the severity of load fluctuations: a larger absolute value indicates a more severe load fluctuation, a faster increase in current deviation between modules, and a higher demand for compensation strength; a smaller absolute value indicates a relatively gentle load fluctuation, and overcompensation can easily trigger system oscillations. This embodiment establishes a positive correlation between the two, enabling the preset compensation value to be dynamically adjusted in real time according to the intensity of load fluctuations. When the load fluctuation is severe, a larger preset compensation value is automatically matched to quickly suppress current deviations with stronger adjustment, avoiding deviation accumulation; when the load fluctuation is gentle, a smaller preset compensation value is automatically adopted, ensuring current sharing while avoiding voltage and current oscillations caused by over-adjustment. Simultaneously, this embodiment can also use a preset limiting range to limit the preset compensation value, preventing the compensation value from exceeding the system's safe range due to an excessively large absolute value of the load rate change, ensuring the safety and reliability of the compensation strategy.

[0046] This method can solve the problem of overcompensation during small-amplitude changes and make up for the deficiency of insufficient compensation during large-amplitude changes. It enables current sharing control to respond quickly to various load changes and maintain the stability of the adjustment process. It can effectively adapt to the load change characteristics of different industries and scenarios, and further improve the operational stability and power supply quality of multi-module parallel systems under complex dynamic conditions.

[0047] In one possible implementation, the specific implementation process of S101 includes: Obtain the load rate of the converter module; If the rate of change of the load rate is greater than a first preset threshold, the converter module is determined to have entered a sudden load condition; the first preset threshold is greater than zero. If the rate of change of the load rate is less than the second preset threshold, the converter module is determined to enter the sudden load unloading condition; the second preset threshold is less than zero.

[0048] In this embodiment, the first preset threshold is a quantification threshold for determining a sudden load increase condition. Its value is greater than zero, representing a critical value for a rapid increase in load rate. When the rate of change of load rate exceeds the first preset threshold, it is determined to be a sudden load increase condition. The second preset threshold is a quantification threshold for determining a sudden load decrease condition. Its value is less than zero, representing a critical value for a rapid decrease in load rate. When the rate of change of load rate is lower than this value, it is determined to be a sudden load decrease condition.

[0049] Specifically, the controller can determine that the converter module has entered a sudden load increase condition when it detects that the rate of change of the load rate is greater than the first preset threshold for N consecutive cycles, and determine that the converter module has entered a sudden load decrease condition when it detects that the rate of change of the load rate is less than the second preset threshold for N consecutive cycles. This improves anti-interference capability and avoids the situation where the control condition is switched incorrectly due to occasional acquisition errors.

[0050] In one possible implementation, the specific implementation process of S102 includes: If the converter module is in a dynamic operating condition, the current sharing loop output value of the converter module in the current control cycle is obtained, and the sign of the current sharing loop output value is extracted and latched in the current communication cycle. Accordingly, the specific implementation process of S103 includes: Within the current communication cycle, the polarity of the preset compensation value is adjusted by using the sign of the current sharing loop output value, and the voltage setpoint of the converter module is compensated by the adjusted preset compensation value.

[0051] In this embodiment, the control cycle is the smallest time unit for the converter module to perform "sampling-calculation-output" and is the local operation cycle of a single converter module, which determines the real-time performance of data sampling and control output; the communication cycle is the smallest time unit for data synchronization between multiple converter modules and is the time reference for system-level collaboration; the communication cycle duration is longer than the control cycle duration.

[0052] When the converter module is under dynamic operating conditions such as sudden load increase or sudden load decrease, the current sharing loop output value of the current control cycle is calculated in real time. Only its positive and negative signs are extracted and latched, and the specific value can be discarded. The sign remains unchanged within the current communication cycle, and the sign is not recalculated or updated during the communication cycle. Furthermore, throughout the entire current communication cycle, the polarity of the preset compensation value is always adjusted using the latched sign, and then the adjusted preset compensation value is superimposed on the voltage setpoint to achieve rapid current sharing compensation.

[0053] The above method not only solves the lag problem of real-time calculation and compensation in traditional flow equalization loops, but also avoids compensation oscillations caused by frequent sign flipping under dynamic operating conditions.

[0054] In one possible implementation, after latching the symbol of the current control cycle, if the symbol of the current sharing loop output value of the control cycle is inconsistent with the latched symbol within the current communication cycle, and this state continues for more than M control cycles, then a symbol consistency check is triggered. This involves calculating the current sharing loop compensation value of the latest control cycle within the current communication cycle, determining its symbol, and if it is confirmed that the symbol has indeed flipped, the latching of the current communication cycle can be terminated early, the symbol updated, and a new latched symbol started within the remaining communication cycles to adjust the polarity of the preset compensation value, thus balancing stability and flexibility. The value of M can range from 2 to 5.

[0055] In one possible implementation, the specific implementation process of compensating the voltage setpoint of the converter module using the adjusted preset compensation value in step S103 includes: The adjusted preset compensation value is added to the voltage setpoint of the converter module to obtain the compensated voltage setpoint. Obtain the actual output voltage value of the converter module, and subtract the actual output voltage value from the compensated voltage setpoint to obtain the voltage difference; The voltage difference is input into the PI controller to obtain the voltage loop output value; Obtain the current loop output value of the converter module, and select the larger value between the voltage loop output value and the current loop output value as the target control quantity, and use the target control quantity to generate the corresponding PWM signal.

[0056] In this embodiment, reference Figure 1 The adjusted preset compensation value is compared with the voltage setpoint U of the converter module. out_ref The values ​​are added together to obtain the compensated voltage setpoint. Then, the actual output voltage value U, which is acquired in real time, is subtracted from the compensated voltage setpoint. out_fdb The voltage difference is obtained and input into a PI controller to obtain the voltage loop output value. The PI controller includes proportional and integral parameters. If the voltage difference is greater than a first value, the proportional parameter is increased and the integral parameter is decreased for rapid deviation response; if the voltage difference is less than a second value, the proportional parameter is decreased and the integral parameter is increased to eliminate steady-state error. The first value is greater than the second value.

[0057] Similarly, in the current loop, the current loop setpoint I is... out_ref Subtract the actual value of the output current I of the converter module acquired in real time. out_fdb The current difference is obtained and input into another PI controller to obtain the current loop output value. This PI controller also includes proportional and integral parameters. If the current difference is greater than a third value, the proportional parameter is increased and the integral parameter is decreased to quickly respond to deviations; if the current difference is less than a fourth value, the proportional parameter is decreased and the integral parameter is increased to eliminate steady-state error.

[0058] Specifically, after obtaining the voltage loop output value, this embodiment can select one of the current loop output value and the voltage loop output value as the target control quantity through a competition module, or it can use the voltage loop output value as the current loop setpoint and then use the current loop output value as the target control quantity. Finally, a PWM signal for controlling the switching network is generated based on the target control quantity.

[0059] As another possible embodiment, when selecting one of the current loop output value and the voltage loop output value as the target control quantity through the competition module, the current loop output value can be multiplied by a first weighting coefficient, and the voltage loop output value can be multiplied by a second weighting coefficient to obtain the corrected current loop output value and voltage loop output value. The first weighting coefficient is greater than the second weighting coefficient. For example, the first weighting coefficient ranges from 0.8 to 1, and the second weighting coefficient ranges from 1 to 1.2.

[0060] The above method leverages the weighting advantage of the current loop to quickly block the risks of overcurrent and reverse circulating current during sudden load increases / decreases, thus establishing a solid safety baseline for current sharing loop regulation. It also retains the influence of the voltage loop weighting to ensure that the rapid compensation of the current sharing loop can be effectively transmitted, avoiding regulation imbalance when there is no weight. This achieves the beneficial effect of balancing safety and current sharing response speed, and improving the stability and adaptability of the system under dynamic operating conditions.

[0061] In this embodiment, after calculating the target control quantity Gf, the target control quantity Gf can be divided by the maximum control quantity Gmax to obtain the target modulation ratio. Finally, the target modulation ratio is input to the modulation module to generate the PWM signal for controlling the converter module.

[0062] In one possible implementation, the specific implementation process for obtaining the current sharing loop output value of the converter module in the current control cycle in S102 includes: Obtain the average current of the multi-module parallel system in the current control cycle; The difference between the actual output current of the converter module and the average current is used to obtain the current sharing difference value. The current sharing difference is input into the PI controller to obtain the output value of the current sharing loop.

[0063] In this embodiment, the average current value is the average level of the actual output current values ​​of all parallel converter modules in the multi-module parallel system, and it is the core reference benchmark for determining whether the current of each module is balanced. The controller obtains the average current value issued by the system host, then subtracts the average current value from the actual output current value of the current converter module to obtain the current sharing difference. Finally, the current sharing difference is input to the PI controller to obtain the output value of the current sharing loop. The PI controller in the current sharing loop also includes proportional and integral parameters. The controller can adjust the proportional and integral parameters according to the magnitude of the current sharing difference. If the current sharing difference is greater than the fifth value, the proportional parameter is increased to speed up the response; if the current sharing difference is less than the sixth difference value, the integral parameter is increased to eliminate steady-state error.

[0064] When the converter module is detected to have transitioned from steady-state to dynamic operation, the sign of the current sharing loop output value is latched after obtaining the sign of the current sharing loop output value for the first control cycle. Simultaneously, the current sharing loop output value is deleted, and the parameters of the PI controller are frozen. When the converter module is detected to have transitioned from dynamic to steady-state operation, the integral and proportional parameters of the PI controller in the current sharing loop are cleared to prevent the integral parameter in the PI controller from accumulating due to large fluctuations in current sharing error during dynamic operation, which could lead to overshoot of the current sharing loop output value when entering steady-state operation.

[0065] As can be seen from the above embodiments, this embodiment first obtains the current sharing difference value of the current cycle to ensure the real-time performance of the reference benchmark, so that the current sharing difference value can truly reflect the deviation between the module current and the system average current under the current dynamic operating conditions; then, the current sharing difference value is input into the PI controller to obtain the current sharing loop output value. The integral characteristic of the PI controller is used to eliminate steady-state error, and the proportional characteristic is used to speed up the response, avoiding the instantaneous fluctuation of the current sharing difference value from causing drastic changes in the current sharing loop output value, ensuring the stability of the current sharing loop output value, and thus enabling the extracted sign to accurately and stably reflect the direction of current deviation, avoiding repeated switching of compensation polarity due to frequent sign flipping, which could cause system oscillation.

[0066] In one possible implementation, after S101, the method provided in this embodiment further includes: If the converter module is in steady-state operation, then calculate the current sharing loop output value of the converter module in the current control cycle; The voltage setpoint of the converter module is compensated by the output value of the current sharing loop in the current control cycle.

[0067] In this embodiment, when the converter module is detected to be in dynamic operating condition, the sign of the current sharing loop output value of the current control cycle is extracted and the sign is latched in the current communication cycle. In the current communication cycle, the control method of S101 to S104 is used to control the converter module. After the current communication cycle ends, the normal current sharing loop control is restored and the normal current sharing loop output value is used to compensate the voltage setpoint.

[0068] It should be understood that the sequence number of each step in the above embodiments does not imply the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present invention.

[0069] The following are device embodiments of the present invention. For details not described in detail, please refer to the corresponding method embodiments described above.

[0070] Figure 3 A schematic diagram of the control device for a multi-module parallel system provided in an embodiment of the present invention is shown. For ease of explanation, only the parts related to the embodiment of the present invention are shown, and are described in detail below: like Figure 3 As shown, the control device 100 of the multi-module parallel system includes: The operating condition detection module 110 is used to detect the operating condition of the converter module; the operating condition includes dynamic operating condition and steady-state operating condition. The symbol extraction module 120 is used to obtain the current sharing loop output value of the converter module in the current control cycle and extract the symbol of the current sharing loop output value if the converter module is in a dynamic operating condition. The voltage compensation module 130 is used to adjust the polarity of the preset compensation value by using the sign of the current sharing ring output value, and to compensate the voltage setpoint of the converter module by using the adjusted preset compensation value. The control module 140 is used to generate a corresponding PWM signal based on the compensated voltage setpoint to drive the switching transistor in the converter module.

[0071] In one possible implementation, the dynamic operating conditions include a sudden load increase condition and a sudden load decrease condition; the voltage compensation module 130 includes: If the converter module is under sudden load conditions, the polarity of the first preset compensation value is adjusted by using the sign of the current sharing loop output value; If the converter module is in a sudden load unloading condition, the polarity of the second preset compensation value is adjusted by the sign of the current sharing ring output value; wherein, the first preset compensation value is not equal to the second preset compensation value.

[0072] In one possible implementation, the voltage compensation module 130 includes: Multiply the sign of the current equalization ring output value by the preset compensation value to obtain the adjusted preset compensation value.

[0073] In one possible implementation, the control device 100 of the multi-module parallel system further includes a preset compensation value calculation module, used for: Obtain the absolute value of the rate of change of the load rate of the converter module; The preset compensation value is determined based on the absolute value of the rate of change; and the absolute value of the rate of change is positively correlated with the preset compensation value.

[0074] In one possible implementation, the operating condition detection module 110 is specifically used for: Obtain the load rate of the converter module; If the rate of change of the load rate is greater than a first preset threshold, the converter module is determined to have entered a sudden load condition; the first preset threshold is greater than zero. If the rate of change of the load rate is less than the second preset threshold, the converter module is determined to enter the sudden load unloading condition; the second preset threshold is less than zero.

[0075] In one possible implementation, the symbol extraction module includes: If the converter module is in a dynamic operating condition, the current sharing loop output value of the converter module in the current control cycle is obtained, and the sign of the current sharing loop output value is extracted and latched in the current communication cycle. Accordingly, the voltage compensation module includes: Within the current communication cycle, the polarity of the preset compensation value is adjusted by using the sign of the current sharing loop output value, and the voltage setpoint of the converter module is compensated by the adjusted preset compensation value.

[0076] In one possible implementation, the voltage compensation module is specifically used for: The adjusted preset compensation value is added to the voltage setpoint of the converter module to obtain the compensated voltage setpoint. Obtain the actual output voltage value of the converter module, and subtract the actual output voltage value from the compensated voltage setpoint to obtain the voltage difference; The voltage difference is input into the PI controller to obtain the voltage loop output value; Obtain the current loop output value of the converter module, and select the larger value between the voltage loop output value and the current loop output value as the target control quantity, and use the target control quantity to generate the corresponding PWM signal.

[0077] In one possible implementation, the symbol extraction module is specifically used for: Obtain the average current of the multi-module parallel system in the current control cycle; The difference between the actual output current of the converter module and the average current is used to obtain the current sharing difference value. The current sharing difference is input into the PI controller to obtain the output value of the current sharing loop.

[0078] In one possible implementation, the control device 100 of the multi-module parallel system further includes a current sharing loop control module, used for: If the converter module is in a dynamic operating condition, then obtain the current sharing loop output value of the converter module in the current control cycle; The voltage setpoint of the converter module is compensated by the output value of the current sharing loop in the current control cycle.

[0079] Figure 4 This is a schematic diagram of the controller provided in an embodiment of the present invention. Figure 4 As shown, the controller 4 in this embodiment includes a processor 40, a memory 41, and a computer program 42 stored in the memory 41 and executable on the processor 40. When the processor 40 executes the computer program 42, it implements the steps in the control method embodiments of the various multi-module parallel systems described above, for example... Figure 2 Steps S101 to S104 are shown. Alternatively, when the processor 40 executes the computer program 42, it implements the functions of each module / unit in the above-described device embodiments.

[0080] For example, the computer program 42 may be divided into one or more modules / units, which are stored in the memory 41 and executed by the processor 40 to complete the present invention. The one or more modules / units may be a series of computer program instruction segments capable of performing a specific function, which describe the execution process of the computer program 42 in the controller 4.

[0081] The controller 4 may include, but is not limited to, a processor 40 and a memory 41. Those skilled in the art will understand that... Figure 4 This is merely an example of controller 4 and does not constitute a limitation on controller 4. It may include more or fewer components than shown, or combine certain components, or different components. For example, the controller may also include input / output devices, network access devices, buses, etc.

[0082] The processor 40 may be a Central Processing Unit (CPU), or other general-purpose processors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. A general-purpose processor may be a microprocessor or any conventional processor.

[0083] The memory 41 can be an internal storage unit of the controller 4, such as a hard disk or memory of the controller 4. The memory 41 can also be an external storage device of the controller 4, such as a plug-in hard disk, Smart Media Card (SMC), Secure Digital (SD) card, or Flash Card equipped on the controller 4. Furthermore, the memory 41 can include both internal storage units and external storage devices of the controller 4. The memory 41 is used to store the computer program and other programs and data required by the controller. The memory 41 can also be used to temporarily store data that has been output or will be output.

[0084] Those skilled in the art will clearly understand that, for the sake of convenience and brevity, the above-described division of functional units and modules is merely an example. In practical applications, the above functions can be assigned to different functional units and modules as needed, that is, the internal structure of the device can be divided into different functional units or modules to complete all or part of the functions described above. The functional units and modules in the embodiments can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit. The integrated unit can be implemented in hardware or as a software functional unit. Furthermore, the specific names of the functional units and modules are only for easy differentiation and are not intended to limit the scope of protection of this application. The specific working process of the units and modules in the above system can be referred to the corresponding process in the foregoing method embodiments, and will not be repeated here.

[0085] In the above embodiments, the descriptions of each embodiment have different focuses. For parts that are not described in detail or recorded in a certain embodiment, please refer to the relevant descriptions of other embodiments.

[0086] Those skilled in the art will recognize that the units and algorithm steps of the various examples described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementations should not be considered beyond the scope of this invention.

[0087] In the embodiments provided by this invention, it should be understood that the disclosed devices / controllers and methods can be implemented in other ways. For example, the device / controller embodiments described above are merely illustrative. For instance, the division of modules or units is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the coupling or direct coupling or communication connection shown or discussed may be through some interfaces; the indirect coupling or communication connection between devices or units may be electrical, mechanical, or other forms.

[0088] The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.

[0089] Furthermore, the functional units in the various embodiments of the present invention can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit. The integrated unit can be implemented in hardware or as a software functional unit.

[0090] If the integrated module / unit is implemented as a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, all or part of the processes in the above embodiments of the present invention can also be implemented by a computer program instructing related hardware. The computer program can be stored in a computer-readable storage medium, and when executed by a processor, it can implement the steps of the control method embodiments of the various multi-module parallel systems described above. The computer program includes computer program code, which can be in the form of source code, object code, executable files, or certain intermediate forms. The computer-readable medium can include: any entity or device capable of carrying the computer program code, recording media, USB flash drives, portable hard drives, magnetic disks, optical disks, computer memory, read-only memory (ROM), random access memory (RAM), electrical carrier signals, telecommunication signals, and software distribution media, etc.

[0091] The above-described embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention, and should all be included within the protection scope of the present invention.

Claims

1. A control method for a multi-module parallel system, characterized in that, Any converter module applied to the multi-module parallel system includes: The operating condition of the converter module is detected; the operating condition includes dynamic operating condition and steady-state operating condition; If the converter module is in a dynamic operating condition, the current sharing loop output value of the converter module in the current control cycle is obtained, and the sign of the current sharing loop output value is extracted. The polarity of the preset compensation value is adjusted by using the sign of the current sharing ring output value, and the voltage setpoint of the converter module is compensated by the adjusted preset compensation value. Based on the compensated voltage setpoint, a corresponding PWM signal is generated to drive the switching transistors in the converter module.

2. The control method for a multi-module parallel system according to claim 1, characterized in that, The dynamic operating conditions include sudden load increase and sudden load decrease; the preset compensation values ​​include a first preset compensation value and a second preset compensation value; The step of adjusting the polarity of the preset compensation value using the sign of the current sharing loop output value includes: If the converter module is under sudden load conditions, the polarity of the first preset compensation value is adjusted by using the sign of the current sharing loop output value; If the converter module is in a sudden load unloading condition, the polarity of the second preset compensation value is adjusted by the sign of the current sharing ring output value; wherein, the first preset compensation value is not equal to the second preset compensation value.

3. The control method for a multi-module parallel system according to claim 1, characterized in that, The step of adjusting the polarity of the preset compensation value using the sign of the current sharing loop output value includes: Multiply the sign of the current equalization ring output value by the preset compensation value to obtain the adjusted preset compensation value.

4. The control method for a multi-module parallel system according to claim 1 or 2, characterized in that, Before adjusting the polarity of the preset compensation value using the sign of the current sharing loop output value, the method further includes: Obtain the absolute value of the rate of change of the load rate of the converter module; The preset compensation value is determined based on the absolute value of the rate of change; and the absolute value of the rate of change is positively correlated with the preset compensation value.

5. The control method for a multi-module parallel system according to claim 1, characterized in that, The detection of the operating condition of the converter module includes: Obtain the load rate of the converter module; If the rate of change of the load rate is greater than a first preset threshold, the converter module is determined to have entered a sudden load condition; the first preset threshold is greater than zero. If the rate of change of the load rate is less than the second preset threshold, the converter module is determined to enter the sudden load unloading condition; the second preset threshold is less than zero.

6. The control method for a multi-module parallel system according to claim 1, characterized in that, If the converter module is in dynamic operating condition, then the current sharing loop output value of the converter module in the current control cycle is obtained, and the sign of the current sharing loop output value is extracted, including: If the converter module is in a dynamic operating condition, the current sharing loop output value of the converter module in the current control cycle is obtained, and the sign of the current sharing loop output value is extracted and latched in the current communication cycle. Accordingly, the step of adjusting the polarity of the preset compensation value by using the sign of the current sharing loop output value, and compensating the voltage setpoint of the converter module by using the adjusted preset compensation value, includes: Within the current communication cycle, the polarity of the preset compensation value is adjusted by using the sign of the current sharing loop output value, and the voltage setpoint of the converter module is compensated by the adjusted preset compensation value.

7. The control method for a multi-module parallel system according to claim 1, characterized in that, After detecting the operating condition of the converter module, the method further includes: If the converter module is in steady-state operation, then calculate the current sharing loop output value of the converter module in the current control cycle; The voltage setpoint of the converter module is compensated by the output value of the current sharing loop in the current control cycle.

8. A control device for a multi-module parallel system, characterized in that, Any converter module applied to the multi-module parallel system includes: The operating condition detection module is used to detect the operating condition of the converter module; the operating condition includes dynamic operating condition and steady-state operating condition. The symbol extraction module is used to obtain the current sharing loop output value of the converter module in the current control cycle and extract the symbol of the current sharing loop output value if the converter module is in a dynamic operating condition. The voltage compensation module is used to adjust the polarity of the preset compensation value by using the sign of the current sharing ring output value, and to compensate the voltage setpoint of the converter module by using the adjusted preset compensation value. The control module is used to generate a corresponding PWM signal based on the compensated voltage setpoint to drive the switching transistors in the converter module.

9. A converter module, characterized in that, include: A switching network and a controller; the switching network includes switching transistors; the controller includes a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that the processor, when executing the computer program, implements the steps of the control method for the multi-module parallel system as described in any one of claims 1 to 7.

10. A multi-module parallel system, characterized in that, Includes the converter module as described in claim 9.

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