Direct current bus voltage surge suppression method and apparatus

Abstract

Disclosed in the present application are a direct current bus voltage surge suppression method and apparatus. The method comprises: monitoring a startup instruction of a photovoltaic system to obtain a first instruction monitoring result; when the first instruction monitoring result indicates that the startup instruction is monitored, acquiring a historical electrical parameter of the photovoltaic system at the previous moment and the current electrical parameter of the photovoltaic system at the current moment, and comparing the current electrical parameter with the historical electrical parameter to obtain an electrical parameter comparison result; when the first instruction monitoring result indicates that no startup instruction is monitored, if a centrifugal unit compressor of the photovoltaic system is started, acquiring an on state of a photovoltaic power generation stage of the photovoltaic system; and, on the basis of the electrical parameter comparison result or the on state, determining an operation mode of a photovoltaic direct-drive centrifugal unit in the photovoltaic system. The present application solves the technical problem of unstable operation of various components on common direct current buses such as unit generators and compressors under the operating conditions such as sudden changes in photovoltaic power generation power and unit mode switching of photovoltaic centrifugal units in the related art.

Description

DC bus voltage surge suppression method and device

[0001] This application claims priority to Chinese Patent Application No. 202411470902.1, filed on October 21, 2024, entitled "Method and Apparatus for Suppressing DC Bus Voltage Surges", the entire contents of which are incorporated herein by reference. Technical Field

[0002] This application relates to the field of power system technology, and more specifically, to a method and apparatus for suppressing DC bus voltage surges. Background Technology

[0003] Photovoltaic centrifugal chillers can cause DC bus voltage adjustments, flickering, and drops, as well as power step changes, under operating conditions such as sudden changes in photovoltaic power generation, unit mode switching, grid faults, and engineering installation and maintenance. In severe cases, the photovoltaic air conditioning system may collapse, causing partial grid paralysis and affecting the reliability of the unit and the user experience.

[0004] The current solution involves determining the relationship between photovoltaic (PV) power generation and the air conditioner compressor power. When PV power generation is less than the power required by the compressor, the compressor frequency is reduced, thereby decreasing the difference between PV power and compressor power consumption and improving system operability. However, this approach, where PV power remains constant while compressor power is reduced, ensures maximizing PV power generation without affecting output. At the same time, reducing compressor power somewhat compromises the user experience. To solve this problem, PV power generation must always be at its maximum, while the compressor power must be maintained according to actual air conditioner usage without derating. This optimal operating control logic introduces a technical challenge: as PV power and centrifugal chiller power fluctuate, the power supply and demand relationship of the unit changes constantly. Sudden changes in PV power generation or large-scale switching of PV-air conditioner power supply modes (such as unit start-up and shutdown) can cause significant spikes or drops in DC bus voltage due to load / power fluctuations, leading to system malfunctions. In particular, for photovoltaic centrifugal chillers without DC / DC links that are directly driven by photovoltaics, the photovoltaic panels, the fully controlled rectifier section, and the compressor-side inverter section are all directly connected to the DC bus of the system. In order to ensure the stable operation of the common DC bus system and prevent problems such as compressor vibration, surge, or even shutdown, the DC bus voltage needs to be kept relatively stable. When changes occur, it also needs to be adjusted as soon as possible to restore stability as quickly as possible.

[0005] Figure 1 shows the topology of a photovoltaic centrifuge with a DC / DC converter in the prior art. As shown in Figure 1, it consists of a photovoltaic panel, a DC / DC converter, a fully controlled rectifier section, an inverter section, and a centrifuge compressor. The DC power generated by the photovoltaic panel first undergoes a single-stage conversion via the DC / DC converter. The voltage on the photovoltaic panel side follows the MPPT optimization change, performing the MPPT optimization function. The DC voltage on the DC bus side remains constant, meeting the requirement for stable output power of the inverter section of the centrifuge compressor, i.e., the requirement for stable DC voltage. However, this topology has a single-stage DC / DC converter, which increases the energy loss of the electricity generated by the photovoltaic panel by 1-2%.

[0006] There is currently no effective solution to the above problems. Summary of the Invention

[0007] This application provides a method and apparatus for suppressing DC bus voltage surges, which at least solves the technical problem of unstable operation of various components on the common DC bus of the unit, such as the generator and compressor, when the photovoltaic power generation of the photovoltaic centrifuge changes suddenly or the unit mode is switched.

[0008] According to one aspect of the embodiments of this application, a method for suppressing DC bus voltage surges is provided, comprising: monitoring a start-up command of a photovoltaic system to obtain a first command monitoring result, wherein the start-up command is used to instruct the inverter in the photovoltaic system to start; when the first command monitoring result indicates that the start-up command has been detected, acquiring historical electrical parameters of the photovoltaic system at the previous moment and current electrical parameters of the photovoltaic system at the current moment, and comparing the historical electrical parameters with the current electrical parameters to obtain an electrical parameter comparison result; when the first command monitoring result indicates that the start-up command has not been detected, if the centrifugal compressor of the photovoltaic system starts, acquiring the on-state of the photovoltaic power generation link of the photovoltaic system; and determining the operating mode of the photovoltaic direct-drive centrifugal chiller unit in the photovoltaic system based on the electrical parameter comparison result or the on-state.

[0009] Optionally, determining the operating mode of the photovoltaic direct-drive centrifugal chiller unit in the photovoltaic system based on the electrical parameter comparison results includes: determining the current state of the compressor in the photovoltaic system when it is determined from the electrical parameter comparison results that the inverter shows a photovoltaic input trend; and determining the operating mode of the photovoltaic direct-drive centrifugal chiller unit in the photovoltaic system based on the current state.

[0010] Optionally, determining the operating mode of the photovoltaic direct-drive centrifugal chiller unit in the photovoltaic system based on the current state includes: when the current state indicates that the compressor is in operation, determining that the photovoltaic DC power of the photovoltaic direct-drive centrifugal chiller unit increases in a predetermined manner so that the photovoltaic direct-drive centrifugal chiller unit enters a photovoltaic stable start-up mode; when the current state indicates that the compressor is in non-operational state, determining that the photovoltaic DC power of the photovoltaic direct-drive centrifugal chiller unit enters an input state so that the photovoltaic direct-drive centrifugal chiller unit enters a maximum power generation mode.

[0011] Optionally, if the centrifugal compressor of the photovoltaic system starts, obtaining the on-state of the photovoltaic power generation link of the photovoltaic system includes: monitoring the shutdown command of the photovoltaic system to obtain a second command monitoring result, wherein the shutdown command is used to instruct the photovoltaic direct-drive centrifugal chiller unit to shut down; when the second command monitoring result indicates that the photovoltaic direct-drive centrifugal chiller unit has received the shutdown command, detecting the photovoltaic power generation link to obtain a photovoltaic power generation link detection result; when the second command monitoring result indicates that the shutdown command has not been received, continuing to monitor the shutdown command of the photovoltaic system; and determining the on-state of the photovoltaic power generation link based on the photovoltaic power generation link detection result.

[0012] Optionally, determining the operating mode of the photovoltaic direct-drive centrifugal chiller unit in the photovoltaic system based on the on state includes: when the on state indicates that the photovoltaic power generation link is turned on, obtaining the current operating frequency of the compressor; comparing the current operating frequency with a preset frequency to obtain a frequency comparison result; and determining the operating mode of the photovoltaic direct-drive centrifugal chiller unit based on the frequency comparison result.

[0013] Optionally, determining the operating mode of the photovoltaic direct-drive centrifugal chiller based on the frequency comparison result includes: when the frequency comparison result indicates that the current operating frequency is less than the preset frequency, determining the operating mode as a rapid shutdown mode of the photovoltaic direct-drive centrifugal chiller; and when the frequency comparison result indicates that the current operating frequency is not less than the preset frequency, determining the operating mode as a steady-state shutdown mode of the photovoltaic direct-drive centrifugal chiller.

[0014] Optionally, when the frequency comparison result indicates that the current operating frequency is not less than the preset frequency, determining the operating mode as the steady-state shutdown mode of the photovoltaic direct-drive centrifugal chiller includes: obtaining the target frequency value of the compressor; reducing the target frequency value to the preset frequency; obtaining the current operating frequency of the compressor again; and when the current operating frequency is less than the preset frequency, shutting down the inverter module of the photovoltaic direct-drive centrifugal chiller to allow the photovoltaic direct-drive centrifugal chiller to enter the steady-state shutdown mode.

[0015] According to another aspect of the embodiments of this application, a DC bus voltage surge suppression device is also provided, comprising: a monitoring module, configured to monitor a start-up command of a photovoltaic system to obtain a first command monitoring result, wherein the start-up command is used to instruct the inverter in the photovoltaic system to start; a first acquisition module, configured to acquire historical electrical parameters of the photovoltaic system at the previous moment and current electrical parameters of the photovoltaic system at the current moment when the first command monitoring result indicates that the start-up command has been detected, and compare the historical electrical parameters with the current electrical parameters to obtain an electrical parameter comparison result; a second acquisition module, configured to acquire the on-state of the photovoltaic power generation link of the photovoltaic system if the centrifugal compressor of the photovoltaic system starts when the first command monitoring result indicates that the start-up command has not been detected; and a determination module, configured to determine the operating mode of the photovoltaic direct-drive centrifugal chiller unit in the photovoltaic system based on the electrical parameter comparison result or the on-state.

[0016] Optionally, the determining module includes: a first determining unit, configured to determine the current state of the compressor in the photovoltaic system when the inverter shows a photovoltaic input trend based on the comparison results of the electrical parameters; and a second determining unit, configured to determine the operating mode of the photovoltaic direct-drive centrifugal chiller unit in the photovoltaic system based on the current state.

[0017] Optionally, the second determining unit includes: a first determining subunit, configured to determine, when the current state indicates that the compressor is in operation, that the photovoltaic DC power of the photovoltaic direct-drive centrifugal chiller unit increases in a predetermined manner so that the photovoltaic direct-drive centrifugal chiller unit enters a photovoltaic stable start-up mode; and a second determining subunit, configured to determine, when the current state indicates that the compressor is in non-operation, that the photovoltaic DC power of the photovoltaic direct-drive centrifugal chiller unit enters an input state so that the photovoltaic direct-drive centrifugal chiller unit enters a maximum power generation mode.

[0018] Optionally, the second acquisition module includes: a first monitoring unit, configured to monitor the shutdown command of the photovoltaic system and obtain a second command monitoring result, wherein the shutdown command is used to instruct the photovoltaic direct-drive centrifugal chiller unit to shut down; a detection unit, configured to detect the photovoltaic power generation link when the second command monitoring result indicates that the photovoltaic direct-drive centrifugal chiller unit has received the shutdown command, and obtain a photovoltaic power generation link detection result; a second monitoring unit, configured to continue monitoring the shutdown command of the photovoltaic system when the second command monitoring result indicates that the shutdown command has not been received; and a third determining unit, configured to determine the on / off state of the photovoltaic power generation link based on the photovoltaic power generation link detection result.

[0019] Optionally, the determining module includes: an acquisition unit, configured to acquire the current operating frequency of the compressor when the on state indicates that the photovoltaic power generation link is on; a comparison unit, configured to compare the current operating frequency with a preset frequency to obtain a frequency comparison result; and a fourth determining unit, configured to determine the operating mode of the photovoltaic direct-drive centrifugal chiller unit based on the frequency comparison result.

[0020] Optionally, the fourth determining unit includes: a third determining subunit, configured to determine the operating mode as a photovoltaic direct-drive centrifugal chiller rapid shutdown mode when the frequency comparison result indicates that the current operating frequency is less than the preset frequency; and a fourth determining subunit, configured to determine the operating mode as a photovoltaic direct-drive centrifugal chiller steady-state shutdown mode when the frequency comparison result indicates that the current operating frequency is not less than the preset frequency.

[0021] Optionally, the fourth determining subunit includes: a first acquiring subunit for acquiring the target frequency value of the compressor; a reducing subunit for reducing the target frequency value to the preset frequency; a second acquiring subunit for acquiring the current operating frequency of the compressor again; and a shutting-down subunit for shutting down the inverter module of the photovoltaic direct-drive centrifugal chiller unit when the current operating frequency is less than the preset frequency, so that the photovoltaic direct-drive centrifugal chiller unit enters the steady-state shutdown mode of the photovoltaic direct-drive centrifugal chiller unit.

[0022] According to another aspect of the embodiments of this application, a photovoltaic direct-drive centrifuge is also provided, which uses the DC bus voltage surge suppression method described in any one of the above-described embodiments.

[0023] According to another aspect of the embodiments of this application, a computer-readable storage medium is also provided, the computer-readable storage medium including a stored program, wherein the program executes the DC bus voltage surge suppression method described in any one of the above embodiments.

[0024] According to another aspect of the embodiments of this application, a processor is also provided, the processor being configured to run a program, wherein the program, when running, executes the DC bus voltage surge suppression method described in any one of the above embodiments.

[0025] According to another aspect of the embodiments of this application, a computer program product is also provided, including computer instructions, which, when executed by a processor, perform the DC bus voltage surge suppression method described in any one of the above embodiments.

[0026] In this embodiment, the start-up command of the photovoltaic system is monitored to obtain a first command monitoring result, wherein the start-up command is used to instruct the inverter in the photovoltaic system to start; when the first command monitoring result indicates that a start-up command has been detected, the historical electrical parameters of the photovoltaic system at the previous moment and the current electrical parameters of the photovoltaic system at the current moment are obtained, and the historical electrical parameters are compared with the current electrical parameters to obtain an electrical parameter comparison result; when the first command monitoring result indicates that no start-up command has been detected, if the centrifugal compressor of the photovoltaic system starts, the on-state of the photovoltaic power generation link of the photovoltaic system is obtained; the operating mode of the photovoltaic direct-drive centrifugal chiller unit in the photovoltaic system is determined according to the electrical parameter comparison result or the on-state. The technical solution provided in this application achieves the goal of determining the operating mode of the photovoltaic direct-drive centrifugal chiller unit by monitoring the start-up and shutdown commands of the photovoltaic system and comparing and analyzing the historical and current electrical parameters of the photovoltaic system, thereby stabilizing and controlling the DC bus voltage. This achieves the technical effect of simultaneously meeting the maximum power generation of photovoltaic power generation and the on-demand, non-derating operation of the centrifugal compressor, improving the stability and reliability of the photovoltaic centrifugal chiller. Furthermore, it solves the technical problem of unstable operation of various components on the common DC bus of the unit, such as the generator and compressor, under operating conditions such as sudden changes in photovoltaic power generation and unit mode switching in related technologies. Attached Figure Description

[0027] The accompanying drawings, which are included to provide a further understanding of this application and form part of this application, illustrate exemplary embodiments of this application and are used to explain this application, but do not constitute an undue limitation of this application. In the drawings:

[0028] Figure 1 is a topology diagram of a photovoltaic centrifuge with a DC / DC stage in the prior art;

[0029] Figure 2 is a hardware structure block diagram of a mobile terminal for a DC bus voltage surge suppression method according to an embodiment of this application.

[0030] Figure 3 is a flowchart of a DC bus voltage surge suppression method according to an embodiment of this application;

[0031] Figure 4 is a flowchart of a DC bus voltage surge suppression method for a photovoltaic centrifuge according to an embodiment of this application;

[0032] Figure 5 is a topology diagram of a photovoltaic direct-drive centrifuge according to an embodiment of this application;

[0033] Figure 6 is a schematic diagram of a DC bus voltage surge suppression device according to an embodiment of this application. Detailed Implementation

[0034] 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.

[0035] 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.

[0036] As described in the background section, in related technologies, mobile robots cannot delete information about moving objects. When the robot returns to the same location, it may detour, leading to excessively long travel time and increased time and energy costs. This application provides a control method and apparatus for a mobile robot, a mobile robot, a computer-readable storage medium, and a processor.

[0037] The technical solutions in the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings.

[0038] The method embodiments provided in this application can be executed in a mobile terminal, computer terminal, or similar computing device. Taking a mobile terminal as an example, FIG2 is a hardware structure block diagram of a mobile terminal for a DC bus voltage surge suppression method according to an embodiment of this application. As shown in FIG2, the mobile terminal may include one or more (only one is shown in FIG2) processors 202 (processor 202 may include, but is not limited to, processing devices such as microprocessors MCU or programmable logic devices FPGA) and a memory 204 for storing data. The mobile terminal may also include a transmission device 206 for communication functions and an input / output device 208. Those skilled in the art will understand that the structure shown in FIG2 is only illustrative and does not limit the structure of the mobile terminal. For example, the mobile terminal may also include more or fewer components than shown in FIG2, or have a different configuration than shown in FIG2.

[0039] The memory 204 can be used to store computer programs, such as application software programs and modules, like the computer program corresponding to the DC bus voltage surge suppression method in this embodiment. The processor 202 executes various functional applications and data processing by running the computer program stored in the memory 204, thus implementing the above-described method. The memory 204 may include high-speed random access memory and non-volatile memory, such as one or more magnetic storage devices, flash memory, or other non-volatile solid-state memory. In some instances, the memory 104 may further include memory remotely located relative to the processor 202, and these remote memories can be connected to the mobile terminal via a network. Examples of the aforementioned networks include, but are not limited to, the Internet, corporate intranets, local area networks, mobile communication networks, and combinations thereof. The transmission device 206 is used to receive or send data via a network. Specific examples of the aforementioned networks may include wireless networks provided by the mobile terminal's communication provider. In one example, the transmission device 206 includes a network interface controller (NIC), which can be connected to other network devices via a base station to communicate with the Internet. In one example, the transmission device 206 may be a radio frequency (RF) module, which is used to communicate with the Internet wirelessly.

[0040] According to an embodiment of this application, a method embodiment for suppressing DC bus voltage surges is provided. It should be noted that the steps shown in the flowchart in the accompanying drawings can be executed in a computer system such as a set of computer-executable instructions. Furthermore, although a logical order is shown in the flowchart, in some cases, the steps shown or described may be executed in a different order than that shown here.

[0041] Figure 3 is a flowchart of a DC bus voltage surge suppression method according to an embodiment of this application. As shown in Figure 3, the method includes the following steps:

[0042] Step S302: Monitor the start-up command of the photovoltaic system to obtain the first command monitoring result, wherein the start-up command is used to instruct the inverter in the photovoltaic system to start.

[0043] In this embodiment, the start-up command (i.e., the first command) of the photovoltaic system is monitored, which can detect the user's start-up command in a timely manner, ensuring that the converter can respond and start up quickly, thereby improving the system's response speed. It can also check for any faults or abnormal conditions, and manage the start-up process more intelligently and efficiently, ensuring the system operates stably and reliably.

[0044] Figure 4 is a flowchart of a DC bus voltage surge suppression method for a photovoltaic centrifuge according to an embodiment of this application. As shown in Figure 4, it is first determined whether a start-up command has been issued to the photovoltaic converter. When a start-up command is detected, the converter is instructed to start.

[0045] Step S304: When the first instruction monitoring result indicates that a power-on instruction has been detected, the historical electrical parameters of the photovoltaic system at the previous moment and the current electrical parameters of the photovoltaic system at the current moment are obtained, and the historical electrical parameters are compared with the current electrical parameters to obtain the electrical parameter comparison result.

[0046] Optionally, the above electrical parameters may include, but are not limited to: open-circuit voltage, short-circuit current, maximum power point voltage, and fill factor.

[0047] In this embodiment, by monitoring the power-on command, it can be ensured that the photovoltaic system responds immediately upon receiving the start-up signal. By analyzing the comparison results of historical and current electrical parameters, voltage surges can be detected in a timely manner, avoiding adverse effects on the system, thereby enabling corresponding suppression measures to be taken to protect the safe operation of the photovoltaic system.

[0048] As shown in Figure 4, if a power-on command is detected at this time, the system allows photovoltaic power to be put into operation, and the DC voltage and current change trends are compared with those of the previous moment.

[0049] Step S306: If the first command monitoring result indicates that no start-up command was detected, and the centrifugal compressor of the photovoltaic system starts, the start-up status of the photovoltaic power generation link of the photovoltaic system is obtained.

[0050] In this embodiment, the on-state of the photovoltaic power generation link in the photovoltaic system can be monitored. By monitoring the start-up status of the centrifuge compressor, it can be determined whether the photovoltaic system is working normally, so that timely measures can be taken to suppress the impact of DC bus voltage, protect the photovoltaic system from excessive voltage impact, extend the service life of the system, and improve the stability and safety of the system.

[0051] Figure 5 is a topology diagram of a photovoltaic direct-drive centrifuge according to an embodiment of this application. As shown in Figure 5, it consists of a photovoltaic panel, a fully controlled rectifier section, an inverter section, and a centrifuge compressor. The DC power generated by the photovoltaic panel enters the inverter section directly to supply the centrifuge compressor without being converted by a DC / DC converter, or directly enters the fully controlled rectifier section to be inverted into AC power for three-phase power grid generation. Compared with Figure 1, this can reduce the energy loss of the first-stage DC / DC conversion stage by 1-2%.

[0052] Step S308: Determine the operating mode of the photovoltaic direct-drive centrifugal chiller unit in the photovoltaic system based on the comparison results of electrical parameters or the start-up status.

[0053] In this embodiment, the specific operating mode of the direct-drive centrifugal chiller is determined by monitoring the electrical parameters or switch status in the photovoltaic system. The operating mode of the direct-drive centrifugal chiller can be adjusted in real time to reduce the impact of DC bus voltage and protect the stable operation of the photovoltaic system.

[0054] As shown in Figure 4, there are four modes to switch between in response to different source load impacts: photovoltaic power stable start-up mode, photovoltaic maximum power generation mode, unit fast shutdown mode, and unit stable shutdown mode.

[0055] As described above, in this embodiment, the photovoltaic system's start-up command is monitored to obtain a first command monitoring result, wherein the start-up command is used to instruct the inverter in the photovoltaic system to start. When the first command monitoring result indicates that a start-up command has been detected, the historical electrical parameters of the photovoltaic system at the previous moment and the current electrical parameters of the photovoltaic system at the current moment are obtained, and the historical electrical parameters are compared with the current electrical parameters to obtain an electrical parameter comparison result. When the first command monitoring result indicates that no start-up command has been detected, if the centrifugal compressor of the photovoltaic system starts, the on-state of the photovoltaic power generation link of the photovoltaic system is obtained. Based on the electrical parameter comparison result or the on-state, the operating mode of the photovoltaic direct-drive centrifugal chiller unit in the photovoltaic system is determined. This achieves the goal of determining the operating mode of the photovoltaic direct-drive centrifugal chiller unit and stably controlling the DC bus voltage by monitoring the start-up and shutdown commands of the photovoltaic system and comparing and analyzing the historical and current electrical parameters of the photovoltaic system. This achieves the technical effect of simultaneously meeting the maximum power generation of photovoltaic power generation and the on-demand, non-derating operation of the centrifugal compressor, improving the stability and reliability of the photovoltaic centrifugal chiller.

[0056] The technical solutions provided in the embodiments of this application solve the technical problem of unstable operation of various components on the common DC bus of the unit, such as the generator and compressor, when the photovoltaic power generation of the photovoltaic centrifuge changes suddenly or the unit mode is switched.

[0057] According to the above embodiments of this application, determining the operating mode of the photovoltaic direct-drive centrifugal chiller unit in the photovoltaic system based on the comparison results of electrical parameters includes: determining the current state of the compressor in the photovoltaic system when it is determined that the inverter shows a trend of photovoltaic input based on the comparison results of electrical parameters; and determining the operating mode of the photovoltaic direct-drive centrifugal chiller unit in the photovoltaic system based on the current state.

[0058] In this embodiment, by comparing electrical parameters to determine whether the inverter shows a trend of photovoltaic input, and detecting whether the compressor is currently running, the current state of the compressor in the photovoltaic system is determined. Based on the current state, the operating mode of the photovoltaic direct-drive centrifugal chiller in the photovoltaic system is determined, which helps to ensure the stable operation of the photovoltaic system.

[0059] In the above embodiments of this application, determining the operating mode of the photovoltaic direct-drive centrifugal chiller unit in the photovoltaic system based on the current state includes: when the current state indicates that the compressor is in operation, determining that the photovoltaic DC power of the photovoltaic direct-drive centrifugal chiller unit increases in a predetermined manner so that the photovoltaic direct-drive centrifugal chiller unit enters the photovoltaic stable start-up mode; when the current state indicates that the compressor is in non-operational state, determining that the photovoltaic DC power of the photovoltaic direct-drive centrifugal chiller unit enters the input state so that the photovoltaic direct-drive centrifugal chiller unit enters the maximum power generation mode.

[0060] In this embodiment, the photovoltaic DC power of the photovoltaic direct-drive centrifugal chiller can be controlled. By adjusting the photovoltaic DC power of the photovoltaic direct-drive centrifugal chiller according to the operating status of the compressor, the power generation mode of the photovoltaic direct-drive centrifugal chiller can be effectively controlled, thereby suppressing the DC bus voltage surge. When the compressor is running, the photovoltaic DC power of the photovoltaic direct-drive centrifugal chiller is increased to make it enter a stable start-up mode, thereby reducing the impact of voltage surge. When the compressor is not running, it enters the maximum power generation mode to generate power to the maximum extent, thereby maintaining the stability of the DC bus voltage.

[0061] As shown in Figure 4, if the compressor is running at this time, the photovoltaic DC power is added to the ramp function for gradual increase control. The ramp function is added to the allowable value of photovoltaic DC power for slow increase control to reduce the instantaneous power impact of the system. At this time, the system is in photovoltaic stable start-up mode. If the compressor is not running at this time, the photovoltaic DC power is directly put into operation. At this time, the system is in photovoltaic maximum power generation mode. This mode can maximize the utilization of photovoltaic resources.

[0062] It should be noted that the ramp function parameters mentioned above are related to the system's photovoltaic capacity, hardware capacitor configuration, and DC bus voltage control algorithm and parameters. Based on the empirical values ​​obtained from testing, for large photovoltaic centrifuge equipment of 500kW and above, the photovoltaic power generation startup speed is generally controlled to rise from 0% to 100% in about 1 second. The ramp function parameters are configured according to this rise time. At this time, it can be ensured that the system can reach the highest power generation as quickly as possible while ensuring low fluctuation of DC bus voltage. At this time, the system is in photovoltaic stable startup mode.

[0063] According to the above embodiments of this application, if the centrifugal compressor of the photovoltaic system starts, the on-state of the photovoltaic power generation link of the photovoltaic system is obtained, including: monitoring the shutdown command of the photovoltaic system to obtain a second command monitoring result, wherein the shutdown command is used to instruct the photovoltaic direct-drive centrifugal chiller unit to shut down; when the second command monitoring result indicates that the photovoltaic direct-drive centrifugal chiller unit has received the shutdown command, the photovoltaic power generation link is detected to obtain a photovoltaic power generation link detection result; when the second command monitoring result indicates that no shutdown command has been received, the monitoring of the shutdown command of the photovoltaic system continues; and the on-state of the photovoltaic power generation link is determined based on the photovoltaic power generation link detection result.

[0064] In this embodiment, the shutdown command (i.e., the second command) of the photovoltaic system can be monitored to ensure that the photovoltaic direct-drive centrifugal chiller can be shut down correctly when it receives the shutdown command. At the same time, by detecting the status of the photovoltaic power generation link, the on-state of the photovoltaic power generation link can be determined, thereby effectively controlling the impact of DC bus voltage and protecting the normal operation of the photovoltaic system.

[0065] As shown in Figure 4, after the centrifuge compressor starts, the system continuously monitors whether the unit has been given a centrifuge compressor shutdown command. If the unit receives a shutdown command, it first checks whether the photovoltaic power generation link of the system is turned on. If the photovoltaic power generation is not turned on, the inverter module is immediately shut down and the compressor stops. At this time, the system is in fast shutdown mode.

[0066] According to the above embodiments of this application, determining the operating mode of a photovoltaic direct-drive centrifugal chiller unit in a photovoltaic system based on the on state includes: when the on state indicates that the photovoltaic power generation link is on, obtaining the current operating frequency of the compressor; comparing the current operating frequency with a preset frequency to obtain a frequency comparison result; and determining the operating mode of the photovoltaic direct-drive centrifugal chiller unit based on the frequency comparison result.

[0067] In this embodiment, the operating mode of the photovoltaic direct-drive centrifugal chiller can be controlled. If the photovoltaic power generation link of the system is turned on, the current operating frequency of the compressor is detected, and the operating mode of the photovoltaic direct-drive centrifugal chiller is determined by comparing the current operating frequency of the compressor with the preset frequency.

[0068] In the above embodiments of this application, determining the operating mode of the photovoltaic direct-drive centrifugal chiller based on the frequency comparison result includes: when the frequency comparison result indicates that the current operating frequency is less than the preset frequency, determining the operating mode as the photovoltaic direct-drive centrifugal chiller fast shutdown mode; and when the frequency comparison result indicates that the current operating frequency is not less than the preset frequency, determining the operating mode as the photovoltaic direct-drive centrifugal chiller steady-state shutdown mode.

[0069] In this embodiment, the shutdown mode of the photovoltaic direct-drive centrifugal chiller can be determined based on the comparison between the current operating frequency and the preset frequency. It is determined whether the current operating frequency of the compressor is less than or equal to the preset value (i.e., the preset frequency). If the frequency requirement is met, a fast shutdown operation is performed. When the current operating frequency is less than the preset frequency, the fast shutdown mode is adopted to shut down the unit as soon as possible, thereby avoiding excessive DC bus voltage surge. When the current operating frequency is not less than the preset frequency, the steady-state shutdown mode is adopted to shut down the unit in an orderly manner, thereby smoothly reducing the DC bus voltage and effectively suppressing DC bus voltage surge.

[0070] In the above embodiments of this application, when the frequency comparison result indicates that the current operating frequency is not less than the preset frequency, the operating mode is determined to be the steady-state shutdown mode of the photovoltaic direct-drive centrifugal chiller, including: obtaining the target frequency value of the compressor; reducing the target frequency value to the preset frequency; obtaining the current operating frequency of the compressor again; and when the current operating frequency is less than the preset frequency, shutting down the inverter module of the photovoltaic direct-drive centrifugal chiller so that the photovoltaic direct-drive centrifugal chiller enters the steady-state shutdown mode of the photovoltaic direct-drive centrifugal chiller.

[0071] In this embodiment, the operating state of the photovoltaic direct-drive centrifugal chiller is controlled by adjusting the operating frequency of the compressor to avoid the impact on the DC bus voltage. When the current operating frequency of the compressor is lower than the preset frequency, the inverter module of the photovoltaic direct-drive centrifugal chiller is shut down to allow it to enter a steady-state shutdown mode, thereby reducing the impact on the DC bus voltage.

[0072] Specifically, if the current operating frequency of the system compressor is greater than the preset value, the target frequency value of the compressor is reduced to the preset value. After detecting that the operating frequency of the compressor is less than or equal to the preset value, the inverter module is shut down. At this time, the system is in stable shutdown mode.

[0073] It should be noted that the above preset value A is related to the compressor capacity, hardware capacitor configuration, and DC bus voltage control algorithm and control parameters. It is generally between 1 / 3 and 1 / 2 of the compressor's rated frequency. The highest allowable shutdown preset value A1 can be found by testing under the premise of low DC bus voltage fluctuation, so that the system can respond to the shutdown command as quickly as possible under the premise of low DC bus voltage fluctuation.

[0074] The technical solutions provided by the above embodiments of this application solve the following problems: 1) the problem of large bus voltage fluctuations and slow recovery under operating conditions such as sudden changes in photovoltaic power generation and unit mode switching in photovoltaic centrifugal chillers; 2) the problem of unstable operation of various components on the common DC bus, such as generators and compressors, under operating conditions such as sudden changes in photovoltaic power generation and unit mode switching in photovoltaic centrifugal chillers; 3) the problem that conventional solutions cannot simultaneously meet the maximum power generation of photovoltaic power generation and the on-demand, non-derating operation of centrifugal chiller compressors. It also has the following beneficial effects: it can simultaneously meet the maximum power generation of photovoltaic power generation and the on-demand, non-derating operation of centrifugal chiller compressors, solving the problems of large bus voltage fluctuations and slow recovery under operating conditions such as sudden changes in photovoltaic power generation and unit mode switching in photovoltaic centrifugal chillers, as well as the problem of unstable operation of various components on the common DC bus, such as generators and compressors.

[0075] In other words, the technical solution provided in this application takes into account a variety of factors and can stably control the photovoltaic power generation to start up without adding a DC / DC link in the topology. It can meet the high stability requirements of the centrifugal compressor for the DC bus voltage and achieve the effect of simultaneously satisfying the stable start-up of photovoltaic power generation and the stable operation of the centrifugal compressor.

[0076] It should be noted that, for the sake of simplicity, the foregoing method embodiments are all described as a series of actions. However, those skilled in the art should understand that this application is not limited to the described order of actions, as some steps may be performed in other orders or simultaneously according to this application. Furthermore, those skilled in the art should also understand that the embodiments described in the specification are preferred embodiments, and the actions and modules involved are not necessarily essential to this application.

[0077] Through the above description of the embodiments, those skilled in the art can clearly understand that the methods according to 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) and includes several instructions to cause a terminal device (which may be a mobile phone, computer, server, or network device, etc.) to execute the methods of the various embodiments of this application.

[0078] According to an embodiment of this application, a DC bus voltage surge suppression device for implementing the above-described DC bus voltage surge suppression method is also provided. Figure 6 is a schematic diagram of the DC bus voltage surge suppression device according to an embodiment of this application. As shown in Figure 6, the device includes: a monitoring module 601, a first acquisition module 603, a second acquisition module 605, and a determination module 607. The DC bus voltage surge suppression device will be described below.

[0079] The monitoring module 601 is used to monitor the start-up command of the photovoltaic system and obtain the first command monitoring result, wherein the start-up command is used to instruct the inverter in the photovoltaic system to start.

[0080] The first acquisition module 603 is used to acquire the historical electrical parameters of the photovoltaic system at the previous moment and the current electrical parameters of the photovoltaic system at the current moment when the first instruction monitoring result indicates that a power-on instruction has been detected, and to compare the historical electrical parameters with the current electrical parameters to obtain the electrical parameter comparison result.

[0081] The second acquisition module 605 is used to acquire the start-up status of the photovoltaic power generation link of the photovoltaic system after the centrifugal compressor of the photovoltaic system starts when the first instruction monitoring result indicates that no start-up instruction has been detected.

[0082] The determination module 607 is used to determine the operating mode of the photovoltaic direct-drive centrifugal chiller unit in the photovoltaic system based on the comparison results of electrical parameters or the on status.

[0083] It should be noted that the monitoring module 601, the first acquisition module 603, the second acquisition module 605, and the determination module 607 mentioned above correspond to steps S302 to S308 in the above embodiments. The four modules and the corresponding steps implement the same instances and application scenarios, but are not limited to the content disclosed in the above embodiments.

[0084] As can be seen from the above, in the scheme described in the above embodiments of this application, firstly, the monitoring module can be used to monitor the start-up command of the photovoltaic system to obtain the first command monitoring result, wherein the start-up command is used to instruct the inverter in the photovoltaic system to start; then, the first acquisition module can be used to acquire the historical electrical parameters of the photovoltaic system at the previous moment and the current electrical parameters of the photovoltaic system at the current moment when the first command monitoring result indicates that the start-up command has been detected, and compare the historical electrical parameters with the current electrical parameters to obtain the electrical parameter comparison result; secondly, the second acquisition module can be used to acquire the start-up status of the photovoltaic power generation link of the photovoltaic system if the centrifugal compressor of the photovoltaic system starts after the first command monitoring result indicates that the start-up command has not been detected; finally, the determination module can determine the operating mode of the photovoltaic direct-drive centrifugal chiller unit in the photovoltaic system according to the electrical parameter comparison result or the start-up status, thereby achieving the purpose of determining the operating mode of the photovoltaic direct-drive centrifugal chiller unit by monitoring the start-up and shutdown commands of the photovoltaic system and comparing and analyzing the historical and current electrical parameters of the photovoltaic system, and stabilizing the DC bus voltage, thereby achieving the technical effect of simultaneously meeting the maximum power generation of photovoltaic power generation and the on-demand non-derating operation of the centrifugal compressor, and improving the stability and reliability of the photovoltaic centrifugal chiller.

[0085] The technical solutions provided in the embodiments of this application solve the technical problem of unstable operation of various components on the common DC bus of the unit, such as the generator and compressor, when the photovoltaic power generation of the photovoltaic centrifuge changes suddenly or the unit mode is switched.

[0086] In one optional embodiment, the determining module includes: a first determining unit, configured to determine the current state of the compressor in the photovoltaic system when it is determined, based on the comparison results of electrical parameters, that the inverter exhibits a photovoltaic input trend; and a second determining unit, configured to determine the operating mode of the photovoltaic direct-drive centrifugal chiller unit in the photovoltaic system based on the current state.

[0087] In one optional embodiment, the second determining unit includes: a first determining subunit, configured to determine, when the current state indicates that the compressor is in a running state, that the photovoltaic DC power of the photovoltaic direct-drive centrifugal chiller unit increases in a predetermined manner so that the photovoltaic direct-drive centrifugal chiller unit enters a photovoltaic stable start-up mode; and a second determining subunit, configured to determine, when the current state indicates that the compressor is in a non-running state, that the photovoltaic DC power of the photovoltaic direct-drive centrifugal chiller unit enters an input state so that the photovoltaic direct-drive centrifugal chiller unit enters a maximum power generation mode.

[0088] In one optional embodiment, the second acquisition module includes: a first monitoring unit, configured to monitor the shutdown command of the photovoltaic system and obtain a second command monitoring result, wherein the shutdown command is used to instruct the photovoltaic direct-drive centrifugal chiller unit to shut down; a detection unit, configured to detect the photovoltaic power generation link when the second command monitoring result indicates that the photovoltaic direct-drive centrifugal chiller unit has received the shutdown command, and obtain a photovoltaic power generation link detection result; a second monitoring unit, configured to continue monitoring the shutdown command of the photovoltaic system when the second command monitoring result indicates that no shutdown command has been received; and a third determining unit, configured to determine the on / off state of the photovoltaic power generation link based on the photovoltaic power generation link detection result.

[0089] In one optional embodiment, the determining module includes: an acquisition unit, used to acquire the current operating frequency of the compressor when the photovoltaic power generation link is turned on in the on state; a comparison unit, used to compare the current operating frequency with a preset frequency to obtain a frequency comparison result; and a fourth determining unit, used to determine the operating mode of the photovoltaic direct-drive centrifugal chiller unit based on the frequency comparison result.

[0090] In one optional embodiment, the fourth determining unit includes: a third determining subunit, configured to determine the operating mode as a rapid shutdown mode of the photovoltaic direct-drive centrifugal chiller when the frequency comparison result indicates that the current operating frequency is less than a preset frequency; and a fourth determining subunit, configured to determine the operating mode as a steady-state shutdown mode of the photovoltaic direct-drive centrifugal chiller when the frequency comparison result indicates that the current operating frequency is not less than a preset frequency.

[0091] In one optional embodiment, the fourth determining subunit includes: a first acquiring subunit for acquiring the target frequency value of the compressor; a reducing subunit for reducing the target frequency value to a preset frequency; a second acquiring subunit for acquiring the current operating frequency of the compressor again; and a shutting-down subunit for shutting down the inverter module of the photovoltaic direct-drive centrifugal chiller unit when the current operating frequency is less than the preset frequency, so that the photovoltaic direct-drive centrifugal chiller unit enters the steady-state shutdown mode of the photovoltaic direct-drive centrifugal chiller unit.

[0092] According to another aspect of the embodiments of this application, a photovoltaic direct-drive centrifuge is also provided, which uses the DC bus voltage surge suppression method described above.

[0093] According to another aspect of the embodiments of this application, a processor is also provided, which is used to run a program, wherein the program executes the DC bus voltage surge suppression method described above during runtime.

[0094] According to another aspect of the embodiments of this application, a computer program product is also provided, including computer instructions, which, when executed by a processor, perform any of the above-described DC bus voltage surge suppression methods.

[0095] According to another aspect of the embodiments of this application, a computer-readable storage medium is also provided, the computer-readable storage medium including a stored program, wherein the program executes the DC bus voltage surge suppression method of any one of the above.

[0096] Optionally, in this embodiment, the computer-readable storage medium may be located in any computer terminal in a group of computer terminals in a computer network, or in any communication device in a group of communication devices.

[0097] Optionally, in this embodiment, the computer-readable storage medium is configured to store program code for performing the following steps: monitoring the start-up command of the photovoltaic system to obtain a first command monitoring result, wherein the start-up command is used to instruct the inverter in the photovoltaic system to start; when the first command monitoring result indicates that a start-up command has been detected, acquiring the historical electrical parameters of the photovoltaic system at the previous moment and the current electrical parameters of the photovoltaic system at the current moment, and comparing the historical electrical parameters with the current electrical parameters to obtain an electrical parameter comparison result; when the first command monitoring result indicates that no start-up command has been detected, if the centrifugal compressor of the photovoltaic system starts, acquiring the on-state of the photovoltaic power generation link of the photovoltaic system; determining the operating mode of the photovoltaic direct-drive centrifugal chiller unit in the photovoltaic system based on the electrical parameter comparison result or the on-state.

[0098] Optionally, in this embodiment, the computer-readable storage medium is configured to store program code for performing the following steps: when it is determined that the inverter shows a trend of photovoltaic input based on the comparison results of electrical parameters, determine the current state of the compressor in the photovoltaic system; and determine the operating mode of the photovoltaic direct-drive centrifugal chiller unit in the photovoltaic system based on the current state.

[0099] Optionally, in this embodiment, the computer-readable storage medium is configured to store program code for performing the following steps: when the current state indicates that the compressor is in operation, determining that the photovoltaic DC power of the photovoltaic direct-drive centrifugal chiller unit increases in a predetermined manner so that the photovoltaic direct-drive centrifugal chiller unit enters a photovoltaic stable start-up mode; when the current state indicates that the compressor is in non-operational state, determining that the photovoltaic DC power of the photovoltaic direct-drive centrifugal chiller unit enters an input state so that the photovoltaic direct-drive centrifugal chiller unit enters a maximum power generation mode.

[0100] Optionally, in this embodiment, the computer-readable storage medium is configured to store program code for performing the following steps: monitoring the shutdown command of the photovoltaic system to obtain a second command monitoring result, wherein the shutdown command is used to instruct the photovoltaic direct-drive centrifugal chiller unit to shut down; when the second command monitoring result indicates that the photovoltaic direct-drive centrifugal chiller unit has received a shutdown command, detecting the photovoltaic power generation link to obtain a photovoltaic power generation link detection result; when the second command monitoring result indicates that no shutdown command has been received, continuing to monitor the shutdown command of the photovoltaic system; and determining the on / off state of the photovoltaic power generation link based on the photovoltaic power generation link detection result.

[0101] Optionally, in this embodiment, the computer-readable storage medium is configured to store program code for performing the following steps: when the photovoltaic power generation stage is turned on in the on state, the current operating frequency of the compressor is obtained; the current operating frequency is compared with a preset frequency to obtain a frequency comparison result; and the operating mode of the photovoltaic direct-drive centrifugal chiller is determined based on the frequency comparison result.

[0102] Optionally, in this embodiment, the computer-readable storage medium is configured to store program code for performing the following steps: when the frequency comparison result indicates that the current operating frequency is less than the preset frequency, determining the operating mode as the photovoltaic direct-drive centrifugal chiller unit fast shutdown mode; when the frequency comparison result indicates that the current operating frequency is not less than the preset frequency, determining the operating mode as the photovoltaic direct-drive centrifugal chiller unit steady-state shutdown mode.

[0103] Optionally, in this embodiment, the computer-readable storage medium is configured to store program code for performing the following steps: obtaining the target frequency value of the compressor; reducing the target frequency value to a preset frequency; obtaining the current operating frequency of the compressor again; and when the current operating frequency is less than the preset frequency, shutting down the inverter module of the photovoltaic direct-drive centrifugal chiller to allow the photovoltaic direct-drive centrifugal chiller to enter the steady-state shutdown mode.

[0104] 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.

[0105] In the above embodiments of this application, the descriptions of each embodiment have different focuses. For parts not described in detail in a certain embodiment, please refer to the relevant descriptions of other embodiments.

[0106] In the several embodiments provided in this application, it should be understood that the disclosed technical content can be implemented in other ways. The device embodiments described above are merely illustrative; for example, the division of units can be a logical functional division, and in actual implementation, there may be other division methods. For instance, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the displayed or discussed mutual coupling, direct coupling, or communication connection may be through some interfaces; the indirect coupling or communication connection between units or modules may be electrical or other forms.

[0107] The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple units. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.

[0108] Furthermore, the functional units in the various embodiments of this application can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit. The integrated unit can be implemented in hardware or as a software functional unit.

[0109] If the integrated unit is implemented as a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of this application, in essence, or the part that contributes to the prior art, or all or part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of this application. The aforementioned storage medium includes various media capable of storing program code, such as a USB flash drive, read-only memory (ROM), random access memory (RAM), portable hard drive, magnetic disk, or optical disk.

[0110] The above description is only a preferred embodiment of this application. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of this application, and these improvements and modifications should also be considered within the scope of protection of this application.

Claims

1. A method for suppressing DC bus voltage surges, applied to a photovoltaic system, the photovoltaic system including a photovoltaic direct-drive centrifugal chiller, comprising: By monitoring the start-up command of the photovoltaic system, a first command monitoring result is obtained, wherein the start-up command is used to instruct the inverter in the photovoltaic system to start; When the first instruction monitoring result indicates that the power-on instruction has been detected, the historical electrical parameters of the photovoltaic system at the previous moment and the current electrical parameters of the photovoltaic system at the current moment are obtained, and the historical electrical parameters are compared with the current electrical parameters to obtain the electrical parameter comparison result; If the first command monitoring result indicates that the start-up command was not detected, and the centrifugal compressor of the photovoltaic system starts, the start-up status of the photovoltaic power generation link of the photovoltaic system is obtained. The operating mode of the photovoltaic direct-drive centrifugal chiller unit in the photovoltaic system is determined based on the comparison results of the electrical parameters or the start-up status.

2. The DC bus voltage surge suppression method according to claim 1, wherein, The operating mode of the photovoltaic direct-drive centrifugal chiller unit in the photovoltaic system is determined based on the comparison results of the electrical parameters, including: When it is determined that the inverter shows a trend of photovoltaic input based on the comparison results of the electrical parameters, the current state of the compressor in the photovoltaic system is determined; The operating mode of the photovoltaic direct-drive centrifugal chiller unit in the photovoltaic system is determined based on the current state.

3. The DC bus voltage surge suppression method according to claim 2, wherein, Determining the operating mode of the photovoltaic direct-drive centrifugal chiller unit in the photovoltaic system based on the current state includes: When the current state indicates that the compressor is in operation, it is determined that the photovoltaic DC power of the photovoltaic direct-drive centrifugal chiller unit increases in a predetermined manner so that the photovoltaic direct-drive centrifugal chiller unit enters the photovoltaic stable start-up mode; When the current state indicates that the compressor is in a non-operating state, it is determined that the photovoltaic DC power of the photovoltaic direct-drive centrifugal chiller unit is put into operation, so that the photovoltaic direct-drive centrifugal chiller unit enters the maximum power generation mode.

4. The DC bus voltage surge suppression method according to claim 1, wherein, If the centrifuge compressor of the photovoltaic system starts, the activation status of the photovoltaic power generation stage of the photovoltaic system is obtained, including: By monitoring the shutdown command of the photovoltaic system, a second command monitoring result is obtained, wherein the shutdown command is used to instruct the photovoltaic direct-drive centrifugal chiller unit to shut down; When the monitoring result of the second instruction indicates that the photovoltaic direct-drive centrifugal chiller unit has received the shutdown instruction, the photovoltaic power generation link is detected to obtain the photovoltaic power generation link detection result. If the second command monitoring result indicates that the shutdown command has not been received, the monitoring of the shutdown command of the photovoltaic system continues. The activation state of the photovoltaic power generation process is determined based on the detection results of the photovoltaic power generation process.

5. The DC bus voltage surge suppression method according to claim 1, wherein, Determining the operating mode of the photovoltaic direct-drive centrifugal chiller unit in the photovoltaic system based on the aforementioned activation status includes: When the "on" state indicates that the photovoltaic power generation process is started, the current operating frequency of the compressor is obtained; The current operating frequency is compared with the preset frequency to obtain the frequency comparison result; The operating mode of the photovoltaic direct-drive centrifugal chiller unit is determined based on the frequency comparison results.

6. The DC bus voltage surge suppression method according to claim 5, wherein, The operating mode of the photovoltaic direct-drive centrifugal chiller unit is determined based on the frequency comparison results, including: When the frequency comparison result indicates that the current operating frequency is less than the preset frequency, the operating mode is determined to be the photovoltaic direct-drive centrifugal chiller unit fast shutdown mode; When the frequency comparison result indicates that the current operating frequency is not less than the preset frequency, the operating mode is determined to be the steady-state shutdown mode of the photovoltaic direct-drive centrifugal chiller.

7. The DC bus voltage surge suppression method according to claim 6, wherein, When the frequency comparison result indicates that the current operating frequency is not less than the preset frequency, the operating mode is determined to be the steady-state shutdown mode of the photovoltaic direct-drive centrifugal chiller unit, including: Obtain the target frequency value of the compressor; Reduce the target frequency value to the preset frequency; Obtain the current operating frequency of the compressor again; When the current operating frequency is less than the preset frequency, the inverter module of the photovoltaic direct-drive centrifugal chiller is shut down so that the photovoltaic direct-drive centrifugal chiller enters the steady-state shutdown mode.

8. A DC bus voltage surge suppression device, applied to a photovoltaic system, the photovoltaic system including a photovoltaic direct-drive centrifugal chiller, comprising: The monitoring module is configured to monitor the start-up command of the photovoltaic system and obtain a first command monitoring result, wherein the start-up command is used to instruct the inverter in the photovoltaic system to start. The first acquisition module is configured to acquire the historical electrical parameters of the photovoltaic system at the previous moment and the current electrical parameters of the photovoltaic system at the current moment when the first instruction monitoring result indicates that the power-on instruction has been detected, and compare the historical electrical parameters with the current electrical parameters to obtain an electrical parameter comparison result; The second acquisition module is configured to acquire the start-up status of the photovoltaic power generation link of the photovoltaic system after the centrifugal compressor of the photovoltaic system starts when the first instruction monitoring result indicates that the start-up instruction has not been detected. The determination module is configured to determine the operating mode of the photovoltaic direct-drive centrifugal chiller unit in the photovoltaic system based on the comparison results of the electrical parameters or the on state.

9. A photovoltaic direct-drive centrifuge, wherein the photovoltaic direct-drive centrifuge uses the DC bus voltage surge suppression method according to any one of claims 1 to 7.

10. A computer-readable storage medium comprising a stored program, wherein, The program executes the DC bus voltage surge suppression method according to any one of claims 1 to 7.

11. A processor for running a program, wherein, When the program runs, it executes the DC bus voltage surge suppression method according to any one of claims 1 to 7.

12. A computer program product comprising computer instructions, which, when executed by a processor, perform the DC bus voltage surge suppression method according to any one of claims 1 to 7.

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