Modular cascaded power converter and control method thereof

Abstract

The application discloses a modular cascaded power converter and a control method thereof. The control method comprises the following steps: controlling to turn on at least one power conversion module in n power conversion modules; acquiring a voltage value and a current value of at least one power conversion module in the turned-on power conversion modules; and determining whether to turn on m power conversion modules in the unturned-on power conversion modules in sequence or to turn off m power conversion modules in the turned-on power conversion modules in sequence according to the voltage value and the current value, wherein m is a positive integer greater than or equal to 1 and smaller than n. The embodiment can realize independent control of starting and stopping of the power conversion modules, and avoid power consumption increase caused by simultaneously turning on all the power conversion modules when only part of the power conversion modules are turned on to meet the load demand.

Description

Technical Field

[0001] This application relates to the field of new energy technology, and in particular to modular cascaded power converters and their control methods. Background Technology

[0002] With the rapid development of society, the application of power systems such as uninterruptible communication power supplies, DC microgrid new energy systems, and high-frequency switching power supplies is becoming increasingly widespread, placing higher demands on the power rating, system capacity, and power density of power converters. These requirements are generally met by combining smaller power conversion modules in series or parallel to create a more efficient converter, known as a modular cascaded power converter.

[0003] However, in modular cascaded power converters, the start and stop of all power conversion modules cannot be independently controlled. All power conversion modules are turned on or off together, which results in the overall efficiency of the power converter not being maximized and the system loss being relatively large. Summary of the Invention

[0004] This application provides a modular cascaded power converter and its control method to achieve independent control and intelligent start-stop of multiple power conversion modules connected in parallel, thereby reducing power consumption and improving overall efficiency.

[0005] According to one aspect of this application, a control method for a modular cascaded power converter is provided, the modular cascaded power converter comprising n parallel power conversion modules, where n is a positive integer greater than or equal to 2, the control method comprising:

[0006] Control the activation of at least one of the n power conversion modules;

[0007] Obtain the voltage and current values ​​of at least one of the activated power conversion modules;

[0008] Based on the voltage and current values, determine whether to sequentially turn on m of the power conversion modules that are not turned on, or determine whether to sequentially turn off m of the power conversion modules that are already turned on, where m is a positive integer greater than or equal to 1 and less than n.

[0009] Optionally, the control to activate at least one of the n power conversion modules includes:

[0010] Start one of the n power conversion modules;

[0011] The step of determining whether to sequentially activate m of the non-activated power conversion modules based on the voltage and current values ​​includes:

[0012] Based on the voltage and current values ​​of the activated power conversion module at different times, determine the voltage change rate and current change rate of the activated power conversion module.

[0013] When the voltage change rate is less than the lower limit of the voltage change threshold and the current change rate is greater than the upper limit of the current change threshold, control to turn on one of the remaining n-1 unactivated power conversion modules.

[0014] Optionally, the control to activate at least one of the n power conversion modules includes:

[0015] Activate n of the aforementioned power conversion modules;

[0016] The step of determining whether to sequentially shut down m of the already activated power conversion modules based on the voltage and current values ​​includes:

[0017] The actual total power of the modular cascaded power converter is determined based on the voltage or current value of each activated power conversion module.

[0018] The rated total power of the modular cascaded power converter is determined based on the rated power of each of the power conversion modules.

[0019] Based on the actual total power and the rated total power, determine the number of power conversion modules to be shut down, and shut them down sequentially.

[0020] Optionally, after determining whether to sequentially turn on m of the non-activated power conversion modules or sequentially turn off m of the activated power conversion modules based on the voltage and current values, the method further includes:

[0021] Once the modular cascaded power converter is operating stably, and after the modular cascaded power converter is operating stably, the total power of the modular cascaded power converter is determined based on the voltage or current value of each activated power conversion module.

[0022] Based on the number of activated power conversion modules and the total power of the modular cascaded power converter, the power of each activated power conversion module is controlled to be equal.

[0023] Optionally, ensuring stable operation of the modular cascaded power converter includes:

[0024] Based on the voltage and current values ​​of each power conversion module that is turned on at different times, determine the voltage change rate and current change rate of the power conversion module;

[0025] The modular cascaded power converter is determined to be operating stably when the voltage change rate of each power conversion module is greater than or equal to the lower limit of the voltage change threshold and less than or equal to the upper limit of the voltage change threshold, and the current change rate of each power conversion module is greater than or equal to the lower limit of the current change threshold and less than or equal to the upper limit of the current change threshold.

[0026] Optionally, after determining whether to sequentially turn on m of the power conversion modules that are not turned on, or whether to sequentially turn off m of the power conversion modules that are turned on, based on the voltage and current values ​​of the power conversion modules, the method further includes:

[0027] Obtain the temperature of each of the power conversion modules that are turned on;

[0028] Based on the temperature of each power conversion module, the voltage and / or current values ​​of each activated power conversion module are controlled to ensure that the temperature of each activated power conversion module is the same.

[0029] Optionally, controlling the voltage and / or current values ​​of each activated power conversion module based on its temperature, so that the temperature of each activated power conversion module is the same, includes:

[0030] Calculate the average temperature based on the temperature of each of the power conversion modules that are turned on;

[0031] If the temperature of the power conversion module is greater than the average temperature, the power of the power conversion module is controlled to decrease; if the temperature of the power conversion module is less than the average temperature, the power of the power conversion module is controlled to increase; if the temperature of the power conversion module is equal to the average temperature, the power of the power conversion module is controlled to remain unchanged at the current power.

[0032] Optionally, the control method further includes:

[0033] The running time of each power conversion module is obtained and accumulated.

[0034] The step of determining whether to sequentially turn on m of the non-activated power conversion modules or sequentially turn off m of the activated power conversion modules based on the voltage and current values, where m is a positive integer greater than or equal to 1 and less than n, includes:

[0035] Based on the voltage value, current value, and the cumulative operating time of each power conversion module, control whether to sequentially turn on m of the power conversion modules that are not turned on, or determine whether to sequentially turn off m of the power conversion modules that are already turned on.

[0036] According to another aspect of this application, a modular cascaded power converter is provided, the modular cascaded power converter comprising:

[0037] n power conversion modules connected in parallel, where n is a positive integer greater than or equal to 2;

[0038] A sampling module is used to acquire the voltage and current values ​​of at least one of the activated power conversion modules.

[0039] The control module is used to determine, based on the voltage and current values, whether to sequentially turn on m of the power conversion modules that are not turned on, or to sequentially turn off m of the power conversion modules that are already turned on, where m is a positive integer greater than or equal to 1 and less than n.

[0040] Optionally, the modular cascaded power converter includes:

[0041] At least one processor; and

[0042] The memory connected to the at least one processor; wherein,

[0043] The memory stores a computer program that can be executed by the at least one processor, which enables the at least one processor to perform the control method for the modular cascaded power converter described above.

[0044] The control method for a modular cascaded power converter provided in this application includes: controlling the activation of at least one power conversion module among n power conversion modules; acquiring the voltage and current values ​​of at least one activated power conversion module; and determining, based on the voltage and current values, whether to sequentially activate m unactivated power conversion modules, or whether to sequentially deactivate m activated power conversion modules, where m is a positive integer greater than or equal to 1 and less than n. This embodiment determines whether the number of currently activated power conversion modules meets the load requirements by collecting the voltage and current values ​​of the power conversion modules, and decides whether to continue activating at least one unactivated power conversion module, or whether to deactivate at least one activated power conversion module, based on the acquired voltage and current values. This ensures that the number of activated power conversion modules meets the load requirements while maximizing the overall efficiency of the power converter. By independently controlling the activation and deactivation of the power conversion modules, it avoids increased power consumption caused by activating all power conversion modules simultaneously when only some modules are needed to meet the load requirements.

[0045] It should be understood that the description in this section is not intended to identify key or essential features of the embodiments of this application, nor is it intended to limit the scope of this application. Other features of this application will become readily apparent from the following description. Attached Figure Description

[0046] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0047] Figure 1 This is a flowchart of a control method for a modular cascaded power converter provided in an embodiment of this application;

[0048] Figure 2 This is a schematic diagram of the structure of an IPOP-type converter provided in an embodiment of this application;

[0049] Figure 3 This is a flowchart of another control method for a modular cascaded power converter provided in an embodiment of this application;

[0050] Figure 4 This is a flowchart of another control method for a modular cascaded power converter provided in an embodiment of this application;

[0051] Figure 5 This is an efficiency comparison chart of the modular cascaded power converters provided in the embodiments of this application;

[0052] Figure 6 This is a flowchart of another control method for a modular cascaded power converter provided in an embodiment of this application;

[0053] Figure 7 This is a flowchart of another control method for a modular cascaded power converter provided in an embodiment of this application;

[0054] Figure 8 This is a schematic diagram of a modular cascaded power converter provided in an embodiment of this application;

[0055] Figure 9 This is a schematic diagram of another modular cascaded power converter provided in the embodiments of this application. Detailed Implementation

[0056] To enable those skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present application, and not all embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative effort should fall within the scope of protection of the present application.

[0057] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of this application described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0058] Figure 1 This is a flowchart illustrating a control method for a modular cascaded power converter according to an embodiment of this application. The modular cascaded power converter includes n power conversion modules connected in parallel. This embodiment is applicable to controlling the independent start and stop of multiple power conversion modules included in the modular cascaded power converter. This method can be executed by the control module of the modular cascaded power converter, which can be implemented in hardware and / or software, for example, by an MCU. Figure 1 As shown, the method includes:

[0059] S10: Controls the activation of at least one of the n power conversion modules.

[0060] The modular cascaded power converter controlled in this embodiment can be an input-parallel-output-parallel (IPOP) converter. In other embodiments, it can also be an input-parallel-output-series converter, or an input-series-output-parallel converter, etc. This embodiment does not specifically limit it in this way.

[0061] The power conversion module in this embodiment can be a DC-DC conversion module, a DC-AC conversion module, an AC-DC conversion module, or a multi-stage conversion module composed of at least two of the aforementioned conversion modules. This embodiment does not impose specific limitations on this. The topology and electrical parameters of the n parallel power conversion modules are all the same. The specific circuit topology can be configured according to actual needs, and this embodiment does not impose specific limitations on this.

[0062] When it is necessary to control the startup of the modular cascaded power converter, at least one of the n power conversion modules can be turned on, for example, one. This embodiment does not specify the number of power conversion modules initially turned on. In order to enable the entire power system to operate normally quickly when the modular cascaded power converter starts up, preferably, all n power conversion modules can be turned on before proceeding with subsequent control steps.

[0063] S20: Obtain the voltage and current values ​​of at least one of the activated power conversion modules.

[0064] Taking the modular cascaded power converter in this embodiment as an example, which is an IPOP-type converter, Figure 2 This is a schematic diagram of the structure of an IPOP-type converter provided in an embodiment of this application, with reference to... Figure 2 Since the n power conversion modules 01 are connected in parallel, the input voltage Ulv and output voltage Uhv of each power conversion module 01 are equal. Therefore, when obtaining the voltage value of each activated power conversion module, it is only necessary to obtain the input voltage Ulv or output voltage Uhv of one of the power conversion modules. The input current or output current of the parallel-connected power conversion modules 01 are different. For example, the input current Lv1 of the first power conversion module, the input current Lv2 of the second power conversion module, and the input current Lvn of the nth power conversion module are all different, as are the output currents Hv1, Hv2, and Hvn of the first power conversion module, second power conversion module, and nth power conversion module. Therefore, to obtain the current value of each power conversion module, the input current or output current of each activated power conversion module 01 needs to be collected. In this embodiment, the input-side voltage Ulv and the input-side current value of each activated power conversion module 01 can be collected as the voltage and current values ​​of the power conversion module. In other embodiments, the output-side voltage Uhv and the output-side current value of each activated power conversion module 01 can also be collected as the voltage and current values ​​of the power conversion module.

[0065] S30: Based on the voltage and current values, determine whether to sequentially turn on m of the non-activated power conversion modules, or determine whether to sequentially turn off m of the activated power conversion modules, where m is a positive integer greater than or equal to 1 and less than n.

[0066] Based on the voltage and current values ​​of the activated power conversion modules, it can be determined whether the number of currently activated power conversion modules meets the load's power requirements. If the load's power requirements are not met, m of the non-activated power conversion modules can be activated one at a time until the requirements are met. Alternatively, if the number of activated power conversion modules exceeds the number required by the current load, m of the activated power conversion modules can be deactivated sequentially.

[0067] This embodiment determines whether the number of currently activated power conversion modules meets the load requirements by collecting the voltage and current values ​​of the power conversion modules. Based on the acquired voltage and current values ​​of the power conversion modules, it decides whether to continue activating at least one of the non-activated power conversion modules, or whether to deactivate at least one of the activated power conversion modules. This ensures that the number of activated power conversion modules meets the load requirements while maximizing the overall efficiency of the power converter. By independently controlling the start and stop of the power conversion modules, it avoids increasing power consumption caused by activating all power conversion modules simultaneously when only some power conversion modules can meet the load requirements.

[0068] Figure 3 A flowchart of another control method for a modular cascaded power converter provided in this application embodiment is shown below. Figure 3 Optionally, the method includes:

[0069] S11: Enable one of the n power conversion modules.

[0070] When controlling the modular cascaded power converter to start up, one of the n power conversion modules can be arbitrarily selected for startup.

[0071] S21: Obtain the voltage and current values ​​of at least one of the activated power conversion modules.

[0072] S31: Determine the voltage change rate and current change rate of the activated power conversion module based on the voltage and current values ​​of the activated power conversion module at different times.

[0073] Specifically, obtain the voltage value Ulv of the power conversion module that is activated at time h. h and current value lv h Obtain the voltage value Ulv of the power conversion module that is activated at time h+1. h+1 and current value lv h+1The rate of change of voltage ΔU = (Ulv) h+1 -Ulv h ) / (t h-1 -t h Voltage fluidization rate ΔU=(lv) h+1 -lv h ) / (t h-1 -t h ).

[0074] S41: When the voltage change rate is less than the lower limit of the voltage change threshold and the current change rate is greater than the upper limit of the current change threshold, control to turn on one of the remaining n-1 unactivated power conversion modules.

[0075] The lower limit of the voltage change threshold is less than zero, and the upper limit of the current change threshold is greater than zero. The voltage and current values ​​of the power conversion module are allowed to fluctuate within a certain range. When the fluctuation exceeds the allowable range, the activated power conversion module may not meet the load requirements. For example, there is a one-second interval between time h and time h+1, with a lower limit of -2 for the voltage change threshold and an upper limit of 1.5 for the current change threshold. At time h+1, if the voltage of the activated power conversion module drops by more than 2V compared to time h, and the current increases by more than 1.5A, it is determined that the activated power conversion module does not meet the load's power requirements, and one of the remaining unactivated power conversion modules needs to be activated. After activating two power conversion modules, it is determined according to S21, S31, and S41 whether to continue activating the remaining power conversion modules until the number of activated power conversion modules meets the load requirements.

[0076] In this embodiment, after activating one power conversion module, the remaining m unactivated power conversion modules are activated sequentially based on their voltage and current values. This process continues until the load requirements are met, thus avoiding increased power consumption caused by activating all power conversion modules.

[0077] Figure 4 A flowchart of another control method for a modular cascaded power converter provided in this application embodiment is shown below. Figure 4 Optionally, the method includes:

[0078] S12: Enable n power conversion modules.

[0079] When controlling the modular cascaded power converter to start working, all n parallel-connected power conversion modules can be started, and then m power conversion modules can be turned off in sequence according to steps S22-S52. This avoids the increase in power consumption caused by all power conversion modules being turned on when only a portion of the power conversion modules need to work to meet the power demand of the load.

[0080] S22: Obtain the voltage and current values ​​of at least one of the activated power conversion modules.

[0081] S32: Determine the actual total power of the modular cascaded power converter based on the voltage or current value of each activated power conversion module.

[0082] The actual total power of a modular cascaded power converter is equal to the sum of the actual power of each activated power conversion module. The actual power of each power conversion module is equal to the product of its voltage and current values.

[0083] S42: Determine the rated total power of the modular cascaded power converter based on the rated power of each power conversion module.

[0084] Each power conversion module has a pre-determined rated power at the factory, and the rated power of each of the n power conversion modules connected in parallel can be stored. The total rated power of the modular cascaded power converter is equal to the sum of the rated power of all the activated power conversion modules. For example, if n power conversion modules are activated, the total rated power of the modular cascaded power converter is equal to the sum of the rated power of the n power conversion modules.

[0085] S52: Determine the number of power conversion modules to be shut down based on the actual total power and the rated total power, and shut them down sequentially.

[0086] If the actual total power exceeds the rated total power, one of the activated power conversion modules will be shut down. After shutting down, it can be determined again according to S22-S52 whether to continue shutting down power conversion modules until the number of activated power conversion modules meets the power requirements of the load.

[0087] In this embodiment, after all n power conversion modules are turned on, the redundant power conversion modules that are turned on are turned off in sequence according to the actual total power and the rated total power, so as to avoid the increase in power consumption caused by turning on all power conversion modules.

[0088] Figure 5 The efficiency comparison chart of the modular cascaded power converter provided in the embodiments of this application is shown in the reference diagram. Figure 5 , Figure 5 This includes three curves showing the increase in power without STT+ configuration, which correspond to... Figure 3 The method shown corresponds to the power reduction curve without STT+ configuration. Figure 4 The method shown, and the lack of STT curve configuration, corresponds to the existing technology of enabling all power conversion modules to work, that is, after the modular cascaded power converter is running stably, all power conversion modules are turned on. Figure 5The horizontal axis represents the load (poewr), and the vertical axis represents the efficiency (efficiency of the modular cascaded power converter). Figure 5 It can be seen that the adoption Figure 3 or Figure 4 The methods shown can all effectively improve the efficiency of modular cascaded power converters, thereby reducing their power consumption.

[0089] Figure 6 A flowchart of another control method for a modular cascaded power converter provided in this application embodiment is shown below. Figure 6 Optionally, the method includes:

[0090] S13: Control the activation of at least one of the n power conversion modules.

[0091] S23: Obtain the voltage and current values ​​of at least one of the activated power conversion modules.

[0092] S33: Based on the voltage and current values, determine whether to sequentially turn on m of the non-activated power conversion modules, or determine whether to sequentially turn off m of the activated power conversion modules, where m is a positive integer greater than or equal to 1 and less than n.

[0093] Optionally, the running time of each power conversion module is acquired and accumulated. Based on the voltage and current values, as well as the accumulated running time of each power conversion module, the system controls whether to sequentially activate m power conversion modules that are not currently activated, or to sequentially deactivate m power conversion modules that are already activated. Specifically, when controlling the power conversion modules to start one by one, i.e., after activating one of the n power conversion modules first, if it is determined based on the voltage and current values ​​of the power conversion modules that still need to be activated, the power conversion module with the shortest accumulated running time is prioritized for activation, so that the accumulated running time of each power conversion module is approximately the same. Alternatively, when controlling all n power conversion modules to start, and then determining based on the power demand of the load that it is not necessary to activate all power conversion modules, the power conversion module with the longest accumulated running time is prioritized for deactivation. Determining whether to activate or deactivate a power conversion module based on its accumulated running time ensures that the accumulated running time of each power conversion module is the same, thereby ensuring that the aging degree of the power conversion modules is consistent and improving the consistency and reliability of the entire modular cascaded power converter.

[0094] S43: After the modular cascaded power converter is operating stably, determine the total power of the modular cascaded power converter based on the voltage or current value of each activated power conversion module.

[0095] Optionally, ensuring stable operation of the modular cascaded power converter includes:

[0096] Based on the voltage and current values ​​of each power conversion module activated at different times, the voltage and current change rates of the power conversion modules are determined. The calculation methods for the voltage and current change rates are detailed in S31 and will not be repeated here.

[0097] The modular cascaded power converter is considered to be operating stably when the voltage change rate of each power conversion module is greater than or equal to the lower limit of the voltage change threshold and less than or equal to the upper limit of the voltage change threshold, and the current change rate of each power conversion module is greater than or equal to the lower limit of the current change threshold and less than or equal to the upper limit of the current change threshold.

[0098] The lower limit of the voltage change threshold is less than zero, and the lower limit of the voltage change threshold is less than the upper limit of the voltage change threshold. The upper limit of the voltage change threshold can be less than 0, equal to 0, or greater than 0; this embodiment does not specifically limit this. For example, when the lower limit of the voltage change threshold is -2, the upper limit of the voltage change threshold is -0.5, and the sampling time interval is 1 second, if the voltage value of the power conversion module at time h+1 is between 0.5V and 2V compared to the voltage value at time h, it indicates that the voltage change of this power conversion module meets the conditions for stable operation. The lower limit of the current change threshold can be greater than zero, equal to zero, or less than zero; this embodiment does not specifically limit this, but the upper limit of the current change threshold is greater than zero. For example, when the upper limit of the current change threshold is 1.5, the lower limit of the current change threshold is 1, and the current value of the power conversion module at time h+1 is between 1A and 1.5A compared to the current value at time h, it indicates that the current change of this power conversion module meets the conditions for stable operation. The modular cascaded power converter is considered to be operating stably when the voltage and current changes of each activated power conversion module meet the stable operating conditions.

[0099] After the modular cascaded power converter is operating stably, the actual power of each power conversion module is determined by the product of the voltage and current values ​​of each activated power conversion module. The total power of the modular cascaded power converter is equal to the sum of the actual power of each activated power conversion module.

[0100] S53: Based on the number of activated power conversion modules and the total power of the modular cascaded power converter, control the power of each activated power conversion module to be equal.

[0101] The average power of a power converter can be obtained by dividing the total power of the modular cascaded power converter by the number of activated power converter modules. The actual power of each activated power converter module can be made equal to the average power by adjusting the current value input to each activated power converter module.

[0102] This embodiment determines the average power of a power conversion module by calculating the total power of each activated power conversion module and the number of activated power conversion modules. Then, it adjusts the current value of each power conversion module to make the actual power of each power conversion module equal to the average power. This avoids large differences in the actual power between different power conversion modules, which would lead to increased system power consumption. It also reduces the risk of device damage caused by high power of individual devices, thereby improving system reliability and extending device lifespan.

[0103] Figure 7 A flowchart of another control method for a modular cascaded power converter provided in this application embodiment is shown below. Figure 7 Optionally, the method includes:

[0104] S14: Control the activation of at least one of the n power conversion modules.

[0105] S24: Obtain the voltage and current values ​​of at least one of the activated power conversion modules.

[0106] S34: Based on the voltage and current values, determine whether to sequentially turn on m of the non-activated power conversion modules, or determine whether to sequentially turn off m of the activated power conversion modules, where m is a positive integer greater than or equal to 1 and less than n.

[0107] S44: Get the temperature of each power conversion module that is turned on.

[0108] For example, a temperature sensor can be installed within a set range for each power conversion module to obtain the temperature of the power conversion module. During operation, the power of the power conversion modules varies over time, resulting in different temperatures for the power conversion modules. Power conversion modules with higher power generate more heat, thus increasing their own temperature. Therefore, the temperature difference reflects the power differences between the power conversion modules.

[0109] S54: Based on the temperature of each power conversion module, control the voltage and / or current values ​​of each activated power conversion module to ensure that the temperature of each activated power conversion module is the same.

[0110] Optionally, the average temperature can be calculated based on the temperature of each power conversion module that is turned on.

[0111] The average temperature of the power conversion module is equal to the sum of the temperatures of each power conversion module that is turned on, divided by the number of power conversion modules that are turned on.

[0112] If the temperature of the power conversion module is higher than the average temperature, the power of the power conversion module is reduced. If the temperature of the power conversion module is lower than the average temperature, the power of the power conversion module is increased. If the temperature of the power conversion module is equal to the average temperature, the power of the power conversion module is maintained at the current level. Specifically, if the temperature of the power conversion module is higher than the average temperature, it indicates that the power of the power conversion module is relatively high, and the power of the power conversion module can be reduced by decreasing the current. If the temperature of the power conversion module is lower than the average temperature, it indicates that the power of the power conversion module is relatively low, and the power of the power conversion module can be increased by increasing the current. If the temperature of the power conversion module is equal to the average temperature, it indicates that the power of the power conversion module is within a suitable range and no adjustment is required.

[0113] Optionally, after obtaining the temperature of each activated power conversion module, an alarm message can be issued or the power conversion module can be shut down when the temperature of the power conversion module is greater than the upper temperature limit or lower than the lower temperature limit, so as to avoid damage to the device caused by the power conversion module operating in an ultra-high temperature or ultra-low temperature environment.

[0114] This embodiment uses the temperature difference between power conversion modules to reflect the power difference between them, thereby achieving power regulation for each power conversion module. This ensures that the temperature difference between the activated power conversion modules is less than a set threshold, meaning the temperatures of the activated power conversion modules are approximately equal. This prevents damage to devices caused by excessively high temperatures in any one power conversion module, extending device lifespan and improving the overall system efficiency.

[0115] This application also provides a modular cascaded power converter. Figure 8 This is a schematic diagram of a modular cascaded power converter provided in an embodiment of this application, with reference to... Figure 8 Modular cascaded power converters include:

[0116] n parallel power conversion modules 01, where n is a positive integer greater than or equal to 2;

[0117] The sampling module 110 is used to acquire the voltage and current values ​​of at least one of the activated power conversion modules.

[0118] The control module 120 is used to determine, based on the voltage value and the current value, whether to sequentially turn on m of the non-turned-on power conversion modules, or to sequentially turn off m of the turned-on power conversion modules, where m is a positive integer greater than or equal to 1 and less than n.

[0119] The beneficial effects of modular cascaded power converters are the same as those of their control methods, and will not be elaborated further here.

[0120] Figure 9 A schematic diagram of another modular cascaded power converter that can be used to implement this application is shown. For example... Figure 9 As shown, the modular cascaded power converter 10 includes at least one processor 11 and a memory, such as a read-only memory (ROM) 12 or a random access memory (RAM) 13, connected to the at least one processor 11. The memory stores computer programs executable by the at least one processor. The processor 11 can perform various appropriate actions and processes based on the computer program stored in the ROM 12 or loaded from storage unit 18 into the RAM 13. The RAM 13 can also store various programs and data required for the operation of the electronic device 10. The processor 11, ROM 12, and RAM 13 are interconnected via a bus 14. An input / output (I / O) interface 15 is also connected to the bus 14.

[0121] Multiple components in the modular cascaded power converter 10 are connected to the I / O interface 15, including: an input unit 16, such as a keyboard, mouse, etc.; an output unit 17, such as various types of displays, speakers, etc.; a storage unit 18, such as a disk, optical disk, etc.; and a communication unit 19, such as a network card, modem, wireless transceiver, etc. The communication unit 19 allows the electronic device 10 to exchange information / data with other devices through computer networks such as the Internet and / or various telecommunications networks.

[0122] Processor 11 can be a variety of general-purpose and / or special-purpose processing components with processing and computing capabilities. Some examples of processor 11 include, but are not limited to, a central processing unit (CPU), a graphics processing unit (GPU), various special-purpose artificial intelligence (AI) computing chips, various processors running machine learning model algorithms, a digital signal processor (DSP), and any suitable processor, controller, microcontroller, etc. Processor 11 performs the various methods and processes described above, such as the control methods for modular cascaded power converters.

[0123] In some embodiments, the control method for the modular cascaded power converter can be implemented as a computer program tangibly contained in a computer-readable storage medium, such as storage unit 18. In some embodiments, part or all of the computer program can be loaded and / or installed onto the modular cascaded power converter 10 via ROM 12 and / or communication unit 19. When the computer program is loaded into RAM 13 and executed by processor 11, one or more steps of the control method for the modular cascaded power converter described above can be performed. Alternatively, in other embodiments, processor 11 can be configured to perform the control method for the modular cascaded power converter by any other suitable means (e.g., by means of firmware).

[0124] The sequence numbers of the embodiments in this application are for descriptive purposes only and do not represent the superiority or inferiority of the embodiments.

[0125] In this application, the same or similar terms, concepts, technical solutions and / or application scenario descriptions are generally described in detail only when they appear for the first time. When they appear again, they are generally not repeated for the sake of brevity. When understanding the technical solutions and other contents of this application, the same or similar terms, concepts, technical solutions and / or application scenario descriptions that are not described in detail later can be referred to their previous relevant detailed descriptions.

[0126] In this application, the descriptions of the various embodiments 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.

[0127] The technical features of the present application can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of the present application.

[0128] Through the above description of the embodiments, those skilled in the art can clearly understand that the methods of the above embodiments can be implemented by means of software plus necessary general-purpose hardware platforms. Of course, they can also be implemented by hardware, but in many cases the former is a better implementation method. Based on this understanding, the technical solution of this application, in essence, or the part that contributes to the prior art, can be embodied in the form of a software product. This computer software product is stored in a storage medium (such as ROM / RAM, magnetic disk, optical disk) as described above, and includes several instructions to cause a terminal device (which may be an electrical device or a network device, etc.) to execute the methods of each embodiment of this application.

[0129] The above are merely preferred embodiments of this application and do not limit the patent scope of this application. Any equivalent structural or procedural transformations made using the content of this application's specification and drawings, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of this application.

Claims

1. A control method for a modular cascaded power converter, characterized in that, The modular cascaded power converter includes n power conversion modules connected in parallel, where n is a positive integer greater than or equal to 2, and the control method includes: Control the activation of at least one of the n power conversion modules; Obtain the voltage and current values ​​of at least one of the activated power conversion modules; Based on the voltage and current values, determine whether to sequentially activate m of the power conversion modules that are not currently activated; The control to activate at least one of the n power conversion modules includes: Start one of the n power conversion modules; The step of determining whether to sequentially activate m of the non-activated power conversion modules based on the voltage and current values ​​includes: Based on the voltage and current values ​​of the activated power conversion module at different times, determine the voltage change rate and current change rate of the activated power conversion module. When the voltage change rate is less than the lower limit of the voltage change threshold and the current change rate is greater than the upper limit of the current change threshold, control to turn on one of the remaining n-1 unactivated power conversion modules; after turning on two power conversion modules, continue to determine whether to turn on the remaining power conversion modules based on the voltage and current values ​​of the activated power conversion modules, until the number of activated power conversion modules meets the load requirements.

2. The control method according to claim 1, characterized in that, After determining whether to sequentially activate m of the non-activated power conversion modules based on the voltage and current values, the method further includes: Once the modular cascaded power converter is operating stably, and after the modular cascaded power converter is operating stably, the total power of the modular cascaded power converter is determined based on the voltage or current value of each activated power conversion module. Based on the number of activated power conversion modules and the total power of the modular cascaded power converter, the power of each activated power conversion module is controlled to be equal.

3. The control method according to claim 2, characterized in that, Determining the stable operation of the modular cascaded power converter includes: Based on the voltage and current values ​​of each power conversion module that is turned on at different times, determine the voltage change rate and current change rate of the power conversion module; The modular cascaded power converter is determined to be operating stably when the voltage change rate of each power conversion module is greater than or equal to the lower limit of the voltage change threshold and less than or equal to the upper limit of the voltage change threshold, and the current change rate of each power conversion module is greater than or equal to the lower limit of the current change threshold and less than or equal to the upper limit of the current change threshold.

4. The control method according to claim 1, characterized in that, After determining whether to sequentially activate m of the non-activated power conversion modules based on the voltage and current values, the method further includes: Obtain the temperature of each of the power conversion modules that are turned on; Based on the temperature of each power conversion module, the voltage and / or current values ​​of each activated power conversion module are controlled to ensure that the temperature of each activated power conversion module is the same.

5. The control method according to claim 4, characterized in that, The step of controlling the voltage and / or current values ​​of each activated power conversion module according to the temperature of each power conversion module, so that the temperature of each activated power conversion module is the same, includes: Calculate the average temperature based on the temperature of each of the power conversion modules that are turned on; If the temperature of the power conversion module is greater than the average temperature, the power of the power conversion module is controlled to decrease; if the temperature of the power conversion module is less than the average temperature, the power of the power conversion module is controlled to increase; if the temperature of the power conversion module is equal to the average temperature, the power of the power conversion module is controlled to remain unchanged at the current power.

6. A modular cascaded power converter, characterized in that, The modular cascaded power converter includes: n power conversion modules connected in parallel, where n is a positive integer greater than or equal to 2; A sampling module is used to acquire the voltage and current values ​​of one of the activated power conversion modules; The control module is used to determine, based on the voltage and current values, whether to sequentially activate m of the unactivated power conversion modules, where m is a positive integer greater than or equal to 1 and less than n; the control module is used to determine the voltage change rate and current change rate of the activated power conversion modules based on the voltage and current values ​​of the activated power conversion modules at different times; when the voltage change rate is less than the lower limit of the voltage change threshold and the current change rate is greater than the upper limit of the current change threshold, the control module controls the activation of one of the remaining n-1 unactivated power conversion modules; after activating two power conversion modules, the control module is used to determine, based on the voltage and current values ​​of the activated power conversion modules, whether to continue activating the remaining power conversion modules until the number of activated power conversion modules meets the load requirements.

7. A modular cascaded power converter, characterized in that, The modular cascaded power converter includes: At least one processor; and The memory connected to the at least one processor; wherein, The memory stores a computer program that can be executed by the at least one processor, the computer program being executed by the at least one processor to enable the at least one processor to perform the control method for the modular cascaded power converter according to any one of claims 1-5.

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