A power conversion system and method for a DC microgrid

Abstract

The present application provides a power conversion system and method for a DC microgrid, which collects the output voltage and surge power after the last switching cycle; performs saturation simulation on the voltage converter during surge startup according to the output voltage and surge power after the last switching cycle, and obtains the maximum excitation surge current in the current switching cycle and the dynamic lower limit of the current when desaturated; determines the power loss increment between the current switching cycle and the previous switching cycle according to the power supply value of the voltage converter after the last switching cycle and the surge power; generates a driving signal in the current switching cycle according to the loss increment, the maximum excitation surge current and the dynamic lower limit of the current when desaturated, and adjusts the duty cycle of the voltage converter during the surge power conversion process based on the driving signal. The scheme of the present application can dynamically adjust the control strategy of the voltage converter during constant power load surge startup, thereby improving the stability of the DC microgrid surge power conversion.

Description

Technical Field

[0001] The present application relates to the technical field of power conversion of power grids, and more specifically, to a power conversion system and method for a direct current microgrid. Background Art

[0002] Power conversion in the power grid is the process of converting one form of electrical power into another form. It is widely used in power electronics and various electrical equipment. Power conversion can achieve changes in parameters such as voltage, current, frequency, and phase to adapt to different load requirements and usage environments.

[0003] In the prior art, constant power loads will cause significant power surges when starting, which will cause voltage fluctuations in the DC microgrid. The constant power load exhibits a negative impedance characteristic, which will amplify the voltage fluctuations. When the voltage fluctuation increases to a certain extent, the power conversion process will be out of the control of the voltage converter, thereby destroying the stability of the DC microgrid. Therefore, how to dynamically adjust the control strategy of the voltage converter when the constant power load surges to start up to improve the stability of the DC microgrid surge power conversion has become a difficult problem faced by the industry. Summary of the invention

[0004] The present application provides a power conversion system and method for a DC microgrid, which can dynamically adjust the control strategy of a voltage converter when a constant power load surges and improve the stability of surge power conversion in the DC microgrid.

[0005] In a first aspect, the present application provides a surge power conversion control method for controlling a voltage converter in a DC microgrid to perform surge power conversion, the method comprising:

[0006] collecting the output voltage and surge power of the voltage converter after the last switching cycle;

[0007] Determine a reference current required for surge starting in the current switching cycle according to the output voltage and surge power of the voltage converter after the last switching cycle, and perform saturation simulation on the voltage converter during surge starting based on the reference current to obtain a maximum excitation surge current in the current switching cycle and a dynamic lower limit of the current during desaturation;

[0008] Acquire a power supply value of the voltage converter after the last switching cycle, and determine a power loss increment between the current switching cycle and the last switching cycle through the power supply value and the surge power;

[0009] A driving signal in a current switching cycle is generated according to the loss increment, the maximum excitation inrush current and the dynamic lower limit of the desaturation current, and a duty cycle of the voltage converter during surge power conversion is adjusted based on the driving signal.

[0010] In some embodiments, performing saturation simulation on the voltage converter during surge startup based on the reference current to obtain the maximum excitation inrush current in the current switching cycle and the dynamic lower limit of the current during desaturation specifically includes:

[0011] Determine the falling edge of the inductor current when the duty cycle is turned off and saturated according to the output voltage;

[0012] Determine the rising edge of the inductor current when the duty cycle is on and saturated according to the input voltage of the voltage converter;

[0013] Determine the maximum excitation inrush current in the current switching cycle according to the falling edge and the reference current;

[0014] A dynamic lower limit of the current during desaturation in the current switching cycle is determined according to the rising edge and the reference current.

[0015] In some embodiments, determining the power loss increment between the current switching cycle and the previous switching cycle by using the power supply value and the surge power specifically includes:

[0016] determining a power loss in a current switching cycle according to the power supply value and the surge power;

[0017] Get the forward loss of the last switching cycle;

[0018] A power loss increment between a current switching cycle and a previous switching cycle is determined according to the forward loss and the power loss.

[0019] In some embodiments, generating a drive signal in the current switching cycle according to the loss increment, the maximum excitation inrush current and the dynamic lower limit of the desaturation current specifically includes:

[0020] Determine a limit range of current ripple in the current switching cycle according to the loss increment, the maximum excitation inrush current and the dynamic lower limit of the current during desaturation;

[0021] Determining a limited control strategy according to the limited range;

[0022] A drive signal in a current switching cycle is generated based on the defined control strategy.

[0023] In some embodiments, adjusting the duty cycle of the voltage converter during the surge power conversion process based on the driving signal specifically includes:

[0024] If the current driving signal is greater than zero, increasing the duty cycle of the field effect transistor in the voltage converter;

[0025] If the current driving signal is less than zero, reducing the duty cycle of the field effect transistor in the voltage converter;

[0026] If the driving signal is equal to zero at the current moment, the duty cycle of the field effect transistor in the voltage converter is not adjusted.

[0027] In some embodiments, determining the reference current required for surge starting in the current switching cycle based on the output voltage and surge power of the voltage converter after the previous switching cycle means using the ratio of the surge power to the output voltage as the reference current required for surge starting in the current switching cycle.

[0028] In some embodiments, the voltage converter is a DC boost converter.

[0029] In a second aspect, the present application provides a power conversion system for a DC microgrid, the power conversion system for the DC microgrid including a surge power conversion control unit, the surge power conversion control unit is used to control a voltage converter in the DC microgrid to perform surge power conversion, the surge power conversion control unit includes:

[0030] A collection module, used for collecting the output voltage and surge power of the voltage converter after the last switching cycle;

[0031] A processing module, configured to determine a reference current required for surge starting in a current switching cycle according to an output voltage and surge power of the voltage converter after a previous switching cycle, and perform saturation simulation of the voltage converter during surge starting based on the reference current to obtain a maximum excitation surge current in the current switching cycle and a dynamic lower limit of the current during desaturation;

[0032] The processing module is further used to obtain a power supply value of the voltage converter after the last switching cycle, and determine the power loss increment between the current switching cycle and the last switching cycle through the power supply value and the surge power;

[0033] An execution module is used to generate a drive signal in a current switching cycle according to the loss increment, the maximum excitation inrush current and the dynamic lower limit of the current during desaturation, and adjust the duty cycle of the voltage converter during the surge power conversion process based on the drive signal.

[0034] In a third aspect, the present application provides a computer device, comprising a memory and a processor, wherein the memory stores codes, and the processor is configured to obtain the codes and execute the above-mentioned surge power conversion control method.

[0035] In a fourth aspect, the present application provides a computer-readable storage medium, wherein the computer-readable storage medium stores a computer program, and when the computer program is executed by a processor, the above-mentioned surge power conversion control method is implemented.

[0036] The technical solution provided by the embodiments disclosed in this application has the following beneficial effects:

[0037] In the power conversion system and method of the DC microgrid provided in the present application, the output voltage and surge power of the voltage converter after the last switching cycle are first collected; the reference current required for surge starting in the current switching cycle is determined based on the output voltage and surge power of the voltage converter after the last switching cycle, and the saturation simulation of the voltage converter during surge starting is performed based on the reference current to obtain the maximum excitation inrush current in the current switching cycle and the dynamic lower limit of the current during desaturation; the power supply value of the voltage converter after the last switching cycle is obtained, and the power loss increment between the current switching cycle and the last switching cycle is determined through the power supply value and the surge power; the drive signal in the current switching cycle is generated based on the loss increment, the maximum excitation inrush current and the dynamic lower limit of the current during desaturation, and the duty cycle of the voltage converter during surge power conversion is adjusted based on the drive signal.

[0038] It can be seen that the present application simulates the saturation of the voltage converter through the output voltage and surge power after the last switching cycle, and obtains the current of the voltage converter when the duty cycle is maximum (i.e., the maximum excitation surge current) and the current when the duty cycle is minimum (i.e., the dynamic lower limit of the current when desaturated), and then determines the increment of power loss between two adjacent switching cycles, and judges the control strategy in the current switching cycle according to the increment of the loss, and then generates a drive signal for control, and controls the conduction and shutdown of the field effect transistor in the voltage converter through the drive signal. In summary, the present application can dynamically adjust the control strategy of the voltage converter when the constant power load surges and starts, thereby improving the stability of the surge power conversion of the DC microgrid. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 is an exemplary flow chart of a surge power conversion control method according to some embodiments of the present application;

[0040] Figure 2 is a schematic diagram of a voltage converter according to some embodiments of the present application;

[0041] Figure 3 is an exemplary flow chart of determining a driving signal according to some embodiments of the present application;

[0042] Figure 4 is a schematic diagram of the structure of a surge power conversion control unit according to some embodiments of the present application;

[0043] Figure 5 It is a structural schematic diagram of a computer device for implementing a surge power conversion control method according to some embodiments of the present application. DETAILED DESCRIPTION

[0044] In order to better understand the technical solution of the present application, the technical solution of the present application will be described in detail below in conjunction with the accompanying drawings and specific implementation methods.

[0045] refer to Figure 1 , which is an exemplary flow chart of a surge power conversion control method according to some embodiments of the present application. The surge power conversion control method 100 is mainly used to control a voltage converter in a DC microgrid to perform surge power conversion. When implemented specifically, the method mainly includes the following steps:

[0046] In step 101, the output voltage and surge power of the voltage converter after the last switching cycle are collected.

[0047] In some embodiments, reference Figure 2 , which is a schematic diagram of a voltage converter according to some embodiments of the present application, and is specifically described as follows: Input voltage , inductor current , output voltage , output current , drive signal , Constant Power Load (CPL), Analog-to-Digital Converter (ADC), Digital Controller, Digital Pulse Width Modulation (DPWM) and Metal-Oxide-Semiconductor Field-Effect Transistor (MOSFET) where:

[0048] The analog-to-digital converter ADC is used to convert the input voltage , inductor current , output voltage Converting into digital signals and inputting the digital signals into a digital controller;

[0049] The digital controller is used to process and analyze the received digital signal, and convert the analysis result into a digital signal and then input it into the digital pulse width modulation;

[0050] Digital pulse width modulation (DPWM) uses digital signals to generate a driving signal with a specific pulse width. , thereby controlling the on and off of the field effect transistor through the driving signal;

[0051] The field effect transistor MOSFET controls the energy transfer process of the voltage converter by periodically turning on and off, so that the input voltage can be converted into the output voltage required for surge startup.

[0052] It should be noted that Figure 2 The subscripts in the parameters are only used to distinguish different parameters, and do not represent the order of precedence, nor do they limit the parameters. For example, the input voltage and output voltage It is just for distinction to indicate that this is a different voltage parameter.

[0053] In addition, it should be noted that the field effect transistor in the present application is a metal-oxide semiconductor field effect transistor.

[0054] In a specific implementation, the output voltage and surge power of the voltage converter after the last switching cycle can be collected in the following manner, that is, Figure 2 The digital controller of the voltage converter shown directly obtains the output voltage and the output current after the last switching cycle, and uses the product of the output voltage and the output current after the last switching cycle as the surge power after the last switching cycle.

[0055] It should be noted that the switching cycle in the present application refers to the period from when the field effect transistor switches from on to off and then switches back on. During the switching cycle, the field effect transistor undergoes one switch-off action and one switch-on action. The length of the switching cycle can be preset to 30us. Those skilled in the art know that the length of the switching cycle can be preset to other values ​​according to actual needs, which fall within the protection scope of the present invention and will not be repeated here.

[0056] In step 102, a reference current required for surge starting in the current switching cycle is determined based on the output voltage and surge power of the voltage converter after the previous switching cycle, and a saturation simulation of the voltage converter during surge starting is performed based on the reference current to obtain the maximum excitation surge current in the current switching cycle and the dynamic lower limit of the current during desaturation.

[0057] In specific implementation, determining the reference current required for surge starting in the current switching cycle based on the output voltage and surge power after the previous switching cycle of the voltage converter can be achieved in the following manner, namely: the ratio of the surge power to the output voltage can be used as the reference current required for surge starting in the current switching cycle.

[0058] It should be noted that the reference current in the present application refers to the desired target current. After each switching cycle, in order to ensure the stability of surge power conversion, the inductor current needs to be brought closer to the reference current through control means.

[0059] In some embodiments, saturation simulation of the voltage converter during surge startup is performed based on the reference current to obtain the maximum excitation inrush current in the current switching cycle and the dynamic lower limit of the current during desaturation can be achieved by the following steps:

[0060] Determine the falling edge of the inductor current when the duty cycle is turned off and saturated according to the output voltage;

[0061] Determine the rising edge of the inductor current when the duty cycle is on and saturated according to the input voltage of the voltage converter;

[0062] Determine the maximum excitation inrush current in the current switching cycle according to the falling edge and the reference current;

[0063] A dynamic lower limit of the current during desaturation in the current switching cycle is determined according to the rising edge and the reference current.

[0064] It should be noted that in the present application, the saturation simulation of the voltage converter during surge start-up based on the reference current refers to determining the falling edge of the inductor current when the duty cycle is turned off and saturated according to the output voltage; and determining the rising edge of the inductor current when the duty cycle is turned on and saturated according to the input voltage of the voltage converter.

[0065] In a specific implementation, determining the falling edge of the inductor current when the duty cycle is turned off and saturated according to the output voltage can be achieved in the following manner, namely: when the duty cycle is turned off and saturated, the inductor is used for discharge in the entire switching cycle, that is, the output voltage can be subtracted from the input voltage, and then the obtained difference is multiplied by the length of the switching cycle, and the obtained value is divided by the inductance value, and the obtained value is used as the slope of the falling edge of the inductor current when the duty cycle is turned off and saturated.

[0066] It should be noted that the falling edge in the present application refers to the process of the inductor current falling when the duty cycle is turned off and saturated, and the slope of the falling edge is the maximum rate at which the inductor current falls.

[0067] In a specific implementation, determining the rising edge of the inductor current when the duty cycle is saturated according to the input voltage of the voltage converter can be achieved in the following manner, namely: when the duty cycle is saturated, the inductor is charged during the entire switching cycle, that is, the input voltage can be multiplied by the length of the switching cycle, and the obtained value can be divided by the inductance value, and the obtained value can be used as the slope of the rising edge of the inductor current when the duty cycle is saturated.

[0068] It should be noted that the rising edge in the present application refers to the process of the inductor current rising when the duty cycle is saturated, and the slope of the rising edge is the maximum rate of increase of the inductor current.

[0069] In specific implementation, determining the maximum excitation inrush current in the current switching cycle based on the falling edge and the reference current can be achieved in the following manner, namely: the reference current can be added to the slope of the falling edge, and then the obtained value is used as the maximum excitation inrush current in the current switching cycle.

[0070] It should be noted that the excitation inrush current in this application refers to the instantaneous large current generated by the sudden change in the magnetization state of the iron core during surge starting, and the maximum excitation inrush current refers to the maximum inductive current in power conversion.

[0071] In specific implementation, determining the dynamic lower limit of the current during desaturation in the current switching cycle based on the rising edge and the reference current can be achieved in the following manner, namely: the slope of the rising edge can be subtracted from the reference current, and the obtained value can be used as the dynamic lower limit of the current during desaturation in the current switching cycle.

[0072] It should be noted that the dynamic lower limit of the current during desaturation in this application refers to the minimum inductor current in power conversion. During desaturation, in order to prevent the bus voltage fluctuation of the DC microgrid from getting out of control, it is necessary to adjust the value of the inductor current within a limited range. The dynamic lower limit is the minimum value to which the inductor current can be adjusted.

[0073] In step 103, a power supply value of the voltage converter after the last switching cycle is obtained, and the power loss increment between the current switching cycle and the last switching cycle is determined by the power supply value and the surge power.

[0074] In specific implementation, obtaining the power supply value of the voltage converter after the last switching cycle can be achieved in the following manner, that is, the output voltage and the inductor current after the switching cycle can be collected, and the product of the output voltage and the inductor current is used as the power supply value after the switching cycle.

[0075] It should be noted that the power supply value in this application refers to the potential power that can be supplied to the load.

[0076] In some embodiments, determining the power loss increment between the current switching cycle and the previous switching cycle by using the power supply value and the surge power can be implemented by the following steps:

[0077] determining a power loss in a current switching cycle according to the power supply value and the surge power;

[0078] Get the forward loss of the last switching cycle;

[0079] A power loss increment between a current switching cycle and a previous switching cycle is determined according to the forward loss and the power loss.

[0080] It should be noted that the power loss in the present application is a parameter indicating the degree of actual power loss when the load starts. The larger the absolute value of the power loss, the greater the deviation between the power supplied by the voltage converter and the power required by the load when the load starts, that is, the greater the actual power loss. The smaller the absolute value of the power loss, the smaller the deviation between the power supplied by the voltage converter and the power required by the load when the load starts, that is, the less the actual power loss. As a preferred embodiment, the power loss in the current switching cycle determined according to the power supply value and the surge power in the present application can be implemented in the following manner, that is: the difference obtained by subtracting the surge power from the power supply value can be used as the power loss after the current switching cycle.

[0081] It should be noted that the forward loss in the present application refers to the power loss in the previous switching cycle. As a preferred embodiment, the forward loss of the previous switching cycle in the present application can be obtained in the following manner, namely: taking the current switching cycle as the nth switching cycle, the output voltage, inductor current and surge power after the n-2th switching cycle can be collected through an analog-to-digital converter, and the difference obtained by subtracting the surge power from the product of the output voltage and the inductor current is taken as the forward loss of the previous switching cycle (i.e., the n-1th switching cycle).

[0082] In addition, it should be noted that the loss increment in the present application represents the degree of increase in power loss between two adjacent switching cycles. The larger the loss increment, the more the power loss increases between two adjacent switching cycles, and the smaller the loss increment, the less the power loss increases between two adjacent switching cycles. In specific implementation, the power loss increment between the current switching cycle and the previous switching cycle can be determined based on the forward loss and the power loss. The following method can be used, that is, the forward loss can be subtracted from the power loss, and the difference obtained is used as the power loss increment between the current switching cycle and the previous switching cycle.

[0083] In step 104, a driving signal in a current switching cycle is generated according to the loss increment, the maximum excitation inrush current and the dynamic lower limit of the desaturation current, and a duty cycle of the voltage converter during surge power conversion is adjusted based on the driving signal.

[0084] In some embodiments, reference Figure 3 , which is an exemplary flow chart of determining a drive signal according to some embodiments of the present application. In the present application, the drive signal in the current switching cycle is generated according to the loss increment, the maximum excitation inrush current and the dynamic lower limit of the current during desaturation, which can be implemented by the following steps:

[0085] In step 1041, a limit range of the current ripple in the current switching cycle is determined according to the loss increment, the maximum excitation inrush current and the dynamic lower limit of the current during desaturation;

[0086] In step 1042, the duty cycle in the last switching cycle is obtained;

[0087] In step 1043, a limited control strategy is determined according to the duty cycle in the previous switching cycle and the limited range;

[0088] In step 1044 , a driving signal in the current switching cycle is generated based on the defined control strategy.

[0089] In specific implementation, determining the limited range of current ripple in the current switching cycle based on the loss increment, the maximum excitation inrush current and the dynamic lower limit of the current during desaturation can be achieved in the following manner, namely: first, judging whether the loss increment is greater than zero; if the loss increment is greater than zero, subtracting the dynamic lower limit of the current during desaturation in the current switching cycle from the reference current of the current switching cycle, and using the obtained value as the upper limit of the limited range of current ripple in the current switching cycle, and setting the lower limit of the limited range of current ripple in the current switching cycle to 0; if the loss increment is less than or equal to zero, subtracting the maximum excitation inrush current in the current switching cycle from the reference current of the current switching cycle, and using the obtained value as the lower limit of the limited range of current ripple in the current switching cycle, and using the reference current of the current switching cycle as the upper limit of the limited range of current ripple in the current switching cycle.

[0090] It should be noted that the defined range in the present application refers to the range of the reference current change rate in a switching cycle, and the change rate refers to the difference between the reference currents in two adjacent switching cycles.

[0091] In addition, it should be noted that only when the change rate of the reference current is within the limited range, can the voltage converter be guaranteed to be always in a controllable state during the operation of surge power conversion.

[0092] It should be noted that the duty cycle in the present application refers to the ratio of the time that the field effect transistor is in the on state in a switching cycle to the length of the switching cycle. In specific implementation, a digital oscilloscope can be connected to the gate of the field effect transistor to directly collect the duty cycle of the previous switching cycle through the duty cycle measurement mode of the digital oscilloscope.

[0093] In specific implementation, the limiting control strategy determined according to the duty cycle in the previous switching cycle and the limited range can be implemented in the following manner, namely: first, multiply the output current by the complement of the duty cycle, subtract the input voltage from the multiplied value, then divide the obtained difference by the inductance value and then multiply by the length of the switching cycle to obtain value A, and subtract the lower limit of the limited range from the obtained value A to obtain value B, and use the obtained value B as the first criterion, then multiply the input voltage by the switching cycle and then divide by the inductance value to obtain value C, add the opposite of the obtained value C to the upper limit of the limited range to obtain value D, and use the obtained value D as the second criterion. The limiting control strategy is: if the first criterion is less than zero, the output result is the opposite of the first criterion, if the first criterion is greater than or equal to zero, then continue to judge whether the second criterion is greater than zero, if the second criterion is greater than zero, then the output result is the opposite of the second criterion, if the second criterion is less than or equal to zero, then the output result is zero.

[0094] It should be noted that the control strategy defined in the present application refers to a control strategy for limiting the current of a voltage converter.

[0095] In specific implementation, the generation of the drive signal in the current switching cycle based on the limited control strategy can be achieved in the following manner, namely: obtaining the output result of the limited control strategy, if the output result is positive, the drive signal is set to 1, if the output result is negative, the drive signal is set to -1, and if the output result is 0, the drive signal is set to 0.

[0096] It should be noted that the driving signal in the present application refers to a digital signal used to control the on and off states of the field effect transistor.

[0097] In some embodiments, adjusting the duty cycle of the voltage converter during the surge power conversion process based on the driving signal may be implemented by the following steps:

[0098] If the current driving signal is greater than zero, increasing the duty cycle of the field effect transistor in the voltage converter;

[0099] If the current driving signal is less than zero, reducing the duty cycle of the field effect transistor in the voltage converter;

[0100] If the driving signal is equal to zero at the current moment, the duty cycle of the field effect transistor in the voltage converter is not adjusted.

[0101] In specific implementation, if the current driving signal is greater than zero, increasing the duty cycle of the field effect transistor in the voltage converter can be achieved in the following manner: if the current driving signal is greater than zero, increasing the duty cycle of the field effect transistor in the current switching cycle by 10%.

[0102] In specific implementation, if the current driving signal is less than zero, reducing the duty cycle of the field effect transistor in the voltage converter can be achieved in the following manner: if the current driving signal is less than zero, reducing the duty cycle of the field effect transistor in the current switching cycle by 10%.

[0103] In addition, in another aspect of the present application, in some embodiments, the present application provides a power conversion system for a DC microgrid, wherein the power conversion system for the DC microgrid includes a surge power conversion control unit, wherein the surge power conversion control unit is used to control a voltage converter in the DC microgrid to perform surge power conversion, Figure 4 , which is a schematic diagram of the structure of a surge power conversion control unit according to some embodiments of the present application, the surge power conversion control unit 400 includes: a collection module 401, a processing module 402 and an execution module 403, which are described as follows:

[0104] The acquisition module 401 in the present application is mainly used to acquire the output voltage and surge power of the voltage converter after the last switching cycle;

[0105] The processing module 402 in the present application is mainly used to determine the reference current required for surge starting in the current switching cycle according to the output voltage and surge power of the voltage converter after the previous switching cycle, and perform saturation simulation of the voltage converter during surge starting based on the reference current to obtain the maximum excitation surge current in the current switching cycle and the dynamic lower limit of the current during desaturation;

[0106] It should be noted that the processing module 402 in the present application is also used for obtaining the power supply value of the voltage converter after the last switching cycle, and determining the power loss increment between the current switching cycle and the last switching cycle through the power supply value and the surge power;

[0107] Execution module 403, in the present application, the execution module 403 is mainly used to generate a drive signal in the current switching cycle according to the loss increment, the maximum excitation surge current and the dynamic lower limit of the current during desaturation, and adjust the duty cycle of the voltage converter during the surge power conversion process based on the drive signal.

[0108] In addition, the present application also provides a computer device, which includes a memory and a processor, wherein the memory stores codes, and the processor is configured to obtain the codes and execute the above-mentioned surge power conversion control method.

[0109] In some embodiments, reference Figure 5, which is a schematic diagram of the structure of a computer device for implementing a surge power conversion control method according to some embodiments of the present application. The surge power conversion control method in the above embodiment can be Figure 5 The computer device 500 shown in the figure is implemented, and the computer device 500 includes at least one processor 501, a communication bus 502, a memory 503 and at least one communication interface 504.

[0110] The processor 501 may be a general-purpose central processing unit (CPU) or an application-specific integrated circuit (ASIC).

[0111] The communication bus 502 may be used to transmit information between the above-mentioned components.

[0112] The memory 503 may be a read-only memory (ROM) or other types of static storage devices that can store static information and instructions, a random access memory (RAM) or other types of dynamic storage devices that can store information and instructions, or an electrically erasable programmable read-only memory (EEPROM), a compact disc read-only memory (CD-ROM) or other optical disc storage, an optical disc storage (including a compressed optical disc, a laser disc, an optical disc, a digital versatile disc, a Blu-ray disc, etc.), a magnetic disk or other magnetic storage device, or any other medium that can be used to carry or store the desired program code in the form of an instruction or data structure and can be accessed by a computer, but is not limited thereto. The memory 503 may exist independently and be connected to the processor 501 via the communication bus 502. The memory 503 may also be integrated with the processor 501.

[0113] The memory 503 is used to store the program code for executing the solution of the present application, and the execution is controlled by the processor 501. The processor 501 is used to execute the program code stored in the memory 503. The program code may include one or more software modules. The surge power conversion control method in the above embodiment can be implemented by the processor 501 and one or more software modules in the program code in the memory 503.

[0114] The communication interface 504 uses any transceiver or other device for communicating with other devices or communication networks, such as Ethernet, radio access network (RAN), wireless local area networks (WLAN), etc.

[0115] In a specific implementation, as an embodiment, a computer device may include multiple processors, each of which may be a single-CPU processor or a multi-CPU processor. The processor here may refer to one or more devices, circuits, and / or processing cores for processing data (e.g., computer program instructions).

[0116] The above-mentioned computer device may be a general-purpose computer device or a special-purpose computer device. In a specific implementation, the computer device may be a desktop computer, a portable computer, a network server, a personal digital assistant (PDA), a mobile phone, a tablet computer, a wireless terminal device, a communication device or an embedded device. The embodiment of the present application does not limit the type of computer device.

[0117] In addition, the present application also provides a computer-readable storage medium, wherein the computer-readable storage medium stores a computer program, and when the computer program is executed by a processor, the above-mentioned surge power conversion control method is implemented.

[0118] In summary, in the power conversion system and method of the DC microgrid disclosed in the embodiment of the present application, first, the output voltage and surge power of the voltage converter after the last switching cycle are collected; the reference current required for surge starting in the current switching cycle is determined based on the output voltage and surge power of the voltage converter after the last switching cycle, and the saturation simulation of the voltage converter during surge starting is performed based on the reference current to obtain the maximum excitation surge current in the current switching cycle and the dynamic lower limit of the current during desaturation; the power supply value of the voltage converter after the last switching cycle is obtained, and the power loss increment between the current switching cycle and the last switching cycle is determined through the power supply value and the surge power; the drive signal in the current switching cycle is generated based on the loss increment, the maximum excitation surge current and the dynamic lower limit of the current during desaturation, and the duty cycle of the voltage converter during the surge power conversion process is adjusted based on the drive signal.

[0119] It can be seen that the present application simulates the saturation of the voltage converter through the output voltage and surge power after the last switching cycle, and obtains the current of the voltage converter when the duty cycle is maximum (i.e., the maximum excitation surge current) and the current when the duty cycle is minimum (i.e., the dynamic lower limit of the current when desaturated), and then determines the increment of power loss between two adjacent switching cycles, and judges the control strategy in the current switching cycle according to the increment of the loss, and then generates a drive signal for control, and controls the conduction and shutdown of the field effect transistor in the voltage converter through the drive signal. In summary, the present application can dynamically adjust the control strategy of the voltage converter when the constant power load surges and starts, thereby improving the stability of the surge power conversion of the DC microgrid.

[0120] Although the preferred embodiments of the present application have been described, those skilled in the art may make other changes and modifications to these embodiments once they have learned the basic creative concept. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications falling within the scope of the present application.

[0121] Obviously, those skilled in the art can make various changes and modifications to the present application without departing from the spirit and scope of the present application. Thus, if these modifications and variations of the present application fall within the scope of the claims of the present application and their equivalents, the present application is also intended to include these modifications and variations.

Claims

1. A surge power conversion control method for controlling a voltage converter in a DC microgrid to perform surge power conversion, characterized in that: The method includes: collecting the output voltage and surge power of the voltage converter after the last switching cycle; Determine a reference current required for surge starting in the current switching cycle according to the output voltage and surge power of the voltage converter after the last switching cycle, and perform saturation simulation on the voltage converter during surge starting based on the reference current to obtain a maximum excitation surge current in the current switching cycle and a dynamic lower limit of the current during desaturation; Acquire a power supply value of the voltage converter after the last switching cycle, and determine a power loss increment between the current switching cycle and the last switching cycle through the power supply value and the surge power; generating a driving signal in a current switching cycle according to the loss increment, the maximum excitation inrush current and the dynamic lower limit of the current during desaturation, and adjusting the duty cycle of the voltage converter during surge power conversion based on the driving signal; The saturation simulation of the voltage converter during surge startup is performed based on the reference current to obtain the maximum excitation surge current in the current switching cycle and the dynamic lower limit of the current during desaturation specifically includes: Determine the falling edge of the inductor current when the duty cycle is turned off and saturated according to the output voltage; Determine the rising edge of the inductor current when the duty cycle is on and saturated according to the input voltage of the voltage converter; Determine the maximum excitation inrush current in the current switching cycle according to the falling edge and the reference current; Determine a dynamic lower limit of the current during desaturation in the current switching cycle according to the rising edge and the reference current; Wherein, determining the maximum excitation inrush current in the current switching cycle according to the falling edge and the reference current means adding the reference current to the slope of the falling edge, and then using the added value as the maximum excitation inrush current in the current switching cycle; Wherein, determining the dynamic lower limit of the current during desaturation in the current switching cycle according to the rising edge and the reference current means subtracting the slope of the rising edge from the reference current, and then using the obtained difference as the dynamic lower limit of the current during desaturation in the current switching cycle; The step of generating a driving signal in the current switching cycle according to the loss increment, the maximum excitation inrush current and the dynamic lower limit of the current during desaturation specifically includes: Determining a limit range of current ripple in a current switching cycle according to the loss increment, the maximum excitation inrush current and the dynamic lower limit of the current during desaturation; Determining a limited control strategy according to the limited range; Generate a drive signal in a current switching cycle based on the defined control strategy; Wherein, determining the limited range of the current ripple in the current switching cycle according to the loss increment, the maximum excitation inrush current and the dynamic lower limit of the current during desaturation specifically includes: First, determine whether the loss increment is greater than zero. If the loss increment is greater than zero, subtract the dynamic lower limit of the current during desaturation in the current switching cycle from the reference current of the current switching cycle, and use the obtained difference as the upper limit of the limited range of the current ripple of the current switching cycle, and set the lower limit of the limited range of the current ripple of the current switching cycle to 0; If the loss increment is less than or equal to zero, the reference current of the current switching cycle is used as the upper limit of the limited range of the current ripple of the current switching cycle, and the reference current of the current switching cycle is subtracted from the maximum excitation surge current in the current switching cycle, and the difference is used as the lower limit of the limited range of the current ripple of the current switching cycle.

2. The method according to claim 1, characterized in that Determining the power loss increment between the current switching cycle and the previous switching cycle by using the power supply value and the surge power specifically includes: determining a power loss in a current switching cycle according to the power supply value and the surge power; Get the forward loss of the last switching cycle; A power loss increment between a current switching cycle and a previous switching cycle is determined according to the forward loss and the power loss.

3. The method according to claim 1, characterized in that Adjusting the duty cycle of the voltage converter during the surge power conversion process based on the driving signal specifically includes: If the current driving signal is greater than zero, increasing the duty cycle of the field effect transistor in the voltage converter; If the current driving signal is less than zero, reducing the duty cycle of the field effect transistor in the voltage converter; If the driving signal is equal to zero at the current moment, the duty cycle of the field effect transistor in the voltage converter is not adjusted.

4. The method according to claim 1, characterized in that Determining the reference current required for surge starting in the current switching cycle according to the output voltage and surge power of the voltage converter after the last switching cycle is to use the ratio of the surge power to the output voltage as the reference current required for surge starting in the current switching cycle.

5. The method according to claim 1, characterized in that The voltage converter is a DC boost converter.

6. A power conversion system for a DC microgrid, which uses the method according to any one of claims 1 to 5 to perform power conversion, the power conversion system for the DC microgrid includes a surge power conversion control unit, the surge power conversion control unit is used to control a voltage converter in the DC microgrid to perform surge power conversion, characterized in that: The surge power conversion control unit comprises: A collection module, used for collecting the output voltage and surge power of the voltage converter after the last switching cycle; A processing module, configured to determine a reference current required for surge starting in a current switching cycle according to an output voltage and surge power of the voltage converter after a previous switching cycle, and perform saturation simulation of the voltage converter during surge starting based on the reference current to obtain a maximum excitation surge current in the current switching cycle and a dynamic lower limit of the current during desaturation; The processing module is further used to obtain a power supply value of the voltage converter after the last switching cycle, and determine the power loss increment between the current switching cycle and the last switching cycle through the power supply value and the surge power; An execution module is used to generate a drive signal in a current switching cycle according to the loss increment, the maximum excitation inrush current and the dynamic lower limit of the current during desaturation, and adjust the duty cycle of the voltage converter during the surge power conversion process based on the drive signal.

7. A computer device, characterized in that: The computer device includes a memory and a processor, wherein the memory stores codes, and the processor is configured to obtain the codes and execute the surge power conversion control method according to any one of claims 1 to 5.

8. A computer-readable storage medium storing a computer program, characterized in that: When the computer program is executed by a processor, the surge power conversion control method according to any one of claims 1 to 5 is implemented.

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