And off-grid refrigeration unit ac power control method, device and variable frequency air conditioner

Abstract

The application relates to the technical field of smart homes, and provides an alternating current power limiting control method and device for a parallel and off-grid refrigerating unit and a variable frequency air conditioner. The method comprises the following steps: acquiring a direct current power supply voltage, an alternating current input detection signal and a current alternating current power supply power of the refrigerating unit, and obtaining a power supply mode of a compressor according to the direct current power supply voltage, the alternating current input detection signal and the current alternating current power supply power; starting an alternating current power limiting function according to the power supply mode; when the power supply mode is an alternating current power supply mode or an alternating current and direct current hybrid power supply mode, and the alternating current power supply power is greater than a preset limiting power, the compressor is controlled to be frequency-reduced at a preset frequency-reducing rate until the current alternating current power supply power is equal to the preset limiting power. The alternating current power limiting control method for the parallel and off-grid refrigerating unit does not increase additional cost, so that the purpose of using all photovoltaic power or using a small part of alternating current, meeting the use requirements of users and reducing the power consumption cost as much as possible is achieved.

Description

Technical Field

[0001] This application relates to the field of smart home technology, and in particular to AC power limiting control methods, devices, and inverter air conditioners for on-grid and off-grid chiller units. Background Technology

[0002] In the application scenarios of grid-connected and off-grid generating units, grid electricity prices fluctuate and are sometimes relatively high. To reduce electricity costs, it is desirable to limit the use of AC power, prioritize the full utilization of photovoltaic (PV) power, and use only a small amount of AC power when necessary, while ensuring the normal operation of the generating units to meet usage requirements. However, existing control methods are insufficient to accurately and effectively meet these demands, and cannot flexibly adjust AC power usage based on grid electricity prices and PV power generation conditions to minimize electricity costs while ensuring stable unit operation. Summary of the Invention

[0003] To address the aforementioned issues, this application proposes an AC power limiting control method, device, and variable frequency air conditioner for on-grid and off-grid chiller units, which minimizes electricity costs while ensuring the normal operation of on-grid and off-grid units and meeting usage requirements.

[0004] Based on the above objectives, this application proposes an AC power limiting control method for on-grid and off-grid chiller units, including: The DC power supply voltage, AC input detection signal, and current AC power supply of the refrigeration unit are obtained. Based on the DC power supply voltage, AC input detection signal, and current AC power supply, the power supply mode of the compressor is obtained. The power supply mode of the compressor includes AC power supply mode, DC power supply mode, and AC / DC hybrid power supply mode. Activate AC power limiting function according to the power supply mode; When the power supply mode is AC power supply mode or AC / DC hybrid power supply mode, and the AC power supply power is greater than the preset limit power, the compressor is controlled to reduce the frequency at a preset frequency reduction rate until the current AC power supply power is equal to the preset limit power.

[0005] In some embodiments, when the DC power supply voltage is less than a first DC voltage threshold and the AC input detection signal detects the presence of AC input, it is determined that the compressor is currently in AC power supply mode.

[0006] In some embodiments, when the power supply mode is AC power supply mode and the current AC power supply power is less than the preset limit power, the compressor is controlled to operate normally; When the power supply mode is AC power supply mode and the preset power limit is a preset value, the compressor is controlled to stop. When the power supply mode is AC power supply mode and the current AC power supply power is greater than the preset limit power, the compressor is controlled to reduce the frequency at a preset frequency reduction rate until the current AC power supply power is equal to the preset limit power, wherein the compressor is reduced to a preset minimum operating frequency.

[0007] In some embodiments, when the AC power supply is less than a first AC power threshold and the AC input detection signal indicates that no AC input has been detected, it is determined that the compressor is currently in DC power supply mode.

[0008] In some embodiments, when the power supply mode is DC power supply mode, the AC power limiting function is turned off.

[0009] In some embodiments, when the DC power supply voltage is not less than a first DC voltage threshold and the AC input detection signal indicates that AC input is detected, the compressor is determined to be in AC / DC hybrid power supply mode.

[0010] In some embodiments, the method further includes: Receive the power limiting percentage and rated power of the unit set by the host computer or controller; The preset power limit is obtained by multiplying the rated power of the unit by the power restriction percentage.

[0011] In some embodiments, when the power supply mode is an AC / DC hybrid power supply mode and the current AC power supply is less than the preset limit power, the compressor is controlled to operate normally; When the power supply mode is AC / DC hybrid power supply mode, and the current AC power supply is greater than the preset limit power, the compressor is controlled to reduce the frequency at a preset frequency reduction rate until the current AC power supply is equal to the preset limit power, wherein the compressor is reduced to a preset minimum operating frequency. When the power supply mode is AC / DC hybrid power supply mode and the preset power limit is a preset value, if the compressor has dropped to the preset minimum operating frequency and the current AC power supply is greater than or equal to the protection power threshold and continues for a preset protection time, low-speed protection shutdown is executed.

[0012] This invention proposes an AC power limiting control device for on-grid and off-grid chiller units, comprising: The data acquisition module is used to acquire the DC power supply voltage, AC input detection signal and current AC power supply of the refrigeration unit, and to obtain the power supply mode of the compressor based on the DC power supply voltage, AC input detection signal and current AC power supply. The power supply mode of the compressor includes AC power supply mode, DC power supply mode and AC / DC hybrid power supply mode. An AC power limiting module is used to activate the AC power limiting function according to the power supply mode. The frequency reduction module is used to control the compressor to reduce the frequency at a preset frequency reduction rate when the power supply mode is AC power supply mode or AC / DC hybrid power supply mode and the AC power supply power is greater than the preset limit power, until the current AC power supply power is equal to the preset limit power.

[0013] This application proposes a variable frequency air conditioner, including: an AC power limiting control device for on-grid and off-grid refrigeration units, or, when performing power supply control, an AC power limiting control method for on-grid and off-grid refrigeration units.

[0014] This application has at least the following beneficial technical effects: This application does not increase additional costs, aiming to achieve the goal of using all photovoltaic power or a small portion of AC power to meet user requirements while minimizing electricity costs; even in situations where there is near-total power curtailment, no DC power, or insufficient photovoltaic power even with DC power access, it also ensures compressor reliability, keeping the compressor operating within a reliable range and avoiding frequent compressor start-stops or protection shutdowns at extremely low frequencies that could damage the compressor.

[0015] This application enables the restriction of AC power usage and priority utilization of photovoltaic power when grid electricity prices are high. Through precise power curtailment control methods, electricity costs are minimized while ensuring the normal operation of both on-grid and off-grid units and meeting usage requirements. Simultaneously, a reasonable compressor control strategy ensures the stability and reliability of unit operation, avoiding unit malfunctions or performance degradation caused by power curtailment operations. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other embodiments can be obtained based on these drawings without creative effort.

[0017] Figure 1 A flowchart of the AC power limiting control method for on-grid and off-grid chiller units provided in this application.

[0018] Figure 2 A schematic diagram of the power input of the AC power limiting control system for the on-grid and off-grid chiller units provided in this application.

[0019] Figure 3 A schematic diagram of the structure of an embodiment of the computer device provided in this application; Figure 4 A schematic diagram of an embodiment of the computer-readable storage medium provided in this application.

[0020] Among them, 1. Working unit; 2. Photovoltaic panel; 3. DC circuit breaker; 4. AC circuit breaker; 5. Mains power. Detailed Implementation

[0021] To make the objectives, technical solutions, and advantages of this application clearer, the embodiments of this application will be further described in detail below with reference to specific examples and accompanying drawings.

[0022] It should be noted that all uses of "first" and "second" in the embodiments of this application are for the purpose of distinguishing two entities or parameters with the same name but different names. It is clear that "first" and "second" are only for the convenience of expression and should not be construed as limiting the embodiments of this application. Subsequent embodiments will not explain this in detail.

[0023] Based on the above objectives, this application proposes an AC power limiting control method for on-grid and off-grid chiller units. Please refer to [link / reference]. Figure 1 Specifically, it includes the following steps: S1: Obtain the DC power supply voltage, AC input detection signal and current AC power supply of the refrigeration unit, and obtain the power supply mode of the compressor based on the DC power supply voltage, AC input detection signal and current AC power supply. The power supply mode of the compressor includes AC power supply mode, DC power supply mode and AC / DC hybrid power supply mode. S2: Activate AC power limiting function according to power supply mode; S3: When the power supply mode is AC power supply mode or AC / DC hybrid power supply mode, and the AC power supply power is greater than the preset limit power, control the compressor to reduce the frequency at the preset frequency reduction rate until the current AC power supply power is equal to the preset limit power.

[0024] The refrigeration unit is either a variable frequency air conditioning unit or a heat pump unit with a refrigeration operation mode.

[0025] The controller enables or disables the AC power limiting function, sets the AC power usage limit ratio, changes the maximum usable AC power, and adjusts the compressor operating frequency to keep the unit's maximum AC power usage below the set target value.

[0026] First, power supply determination is performed. When the photovoltaic panel input voltage is <50V and AC input is detected (i.e., AC voltage >45V), the unit is determined to be in AC-only access mode. When the AC power is <200W and no AC input is detected (i.e., AC voltage <45V), the unit is determined to be in DC-only access mode. When AC input is detected and the photovoltaic panel input voltage is ≥50V, the unit is determined to be in AC and DC access mode simultaneously. The power limit value is calculated as: Power Limit Value = Rated Power × y%, where y% is the power limiting percentage, which is set via the controller.

[0027] When the unit receives an AC power limiting command from the host computer, it enters power limiting control. In AC-only mode, the current AC power is compared to the power limit. If the current AC power is greater than the power limit, the compressor reduces its frequency at a rate of 1Hz / 5s until the current AC power equals the power limit. If the current AC power is less than the power limit, the compressor operates according to normal logic. When the power limit is 0, the compressor immediately stops. When the power limit is greater than 0, the compressor reduces its operating frequency to the lowest possible level.

[0028] When both AC and DC power are connected, the current AC power is compared with the power limit. If the current AC power is greater than the power limit, the compressor reduces its frequency at a rate of 1Hz / 5s until the current AC power is equal to the power limit. If the current AC power is less than the power limit, the compressor operates according to normal logic. When the power limiting function is turned off, the unit exits power limiting control and resumes normal frequency control.

[0029] This application provides precise determination of the power supply status of the chiller unit. Through a specific detection mechanism, when the photovoltaic panel input voltage is below 50V and the detected AC input voltage is above 45V, it is determined that only AC power is connected. If the AC power is above 200W and the detected AC input voltage is above 45V, it is determined that both AC and DC power are connected. If the AC power is below 200W and the detected AC input voltage is below 45V, only DC power is connected. When the chiller unit receives an AC power limiting command from the host computer, it enters the AC power limiting control mode.

[0030] After entering power limiting control, the system monitors the unit's maximum AC power usage in real time and compares the current AC power with the limited power. The limited power is obtained by multiplying the rated power by the user-set power limiting percentage. If the determination is that only AC power is connected, and the current AC power exceeds the limited power, to avoid overpower operation, the unit gradually reduces the compressor frequency at a rate of 1 Hz every 5 seconds until the current AC power equals the limited power, thus achieving precise power control. If the determination is that both AC and DC power are connected, when the limited power is 0, if the compressor frequency has already dropped to the minimum operating frequency, and the current AC power is greater than or equal to a certain threshold, such as 200W, for 10 seconds, a low-speed protection shutdown operation will be executed to protect the compressor from damage.

[0031] For example, if a unit has a rated power of 1000W and the user sets a power limiting percentage of 30%, then the limited power is 300W. If it is determined that only AC power is connected, and the current AC power is 350W, which is greater than the limited power, the compressor will reduce its frequency according to the rules until the current power drops to around 300W. If both AC and DC power are connected and the limited power is 0, the compressor has already reduced to the lowest frequency. If the current AC power reaches 200W for 10 seconds, then the low-speed protection shutdown is triggered.

[0032] This application develops corresponding strategies for different power supply access conditions, which can make full use of DC power to meet the unit's operating needs, reduce dependence on traditional AC mains power, and reduce energy consumption and operating costs.

[0033] In some embodiments, when the DC power supply voltage is less than a first DC voltage threshold and the AC input detection signal detects the presence of AC input, it is determined that the compressor is currently in AC power supply mode.

[0034] When the input voltage of the photovoltaic panel is less than 50V and AC power input is detected, it is determined that only AC power is connected.

[0035] For example, in a real-world scenario, at a certain moment, the photovoltaic panel is detected to have an input voltage of 50V due to insufficient sunlight that day, while the AC voltage is detected to be 220V, meeting the criteria for AC-only access. If an AC power curtailment command is received at this time, the unit will adjust the compressor frequency and other settings accordingly, following the power curtailment control strategy for AC-only access, to control the power consumption of AC power.

[0036] This application quickly identifies that only AC power is available, and promptly switches to AC power supply mode to ensure continuous and stable operation of the equipment and avoid the risk of equipment failure or data loss due to misjudgment of power supply mode.

[0037] In some embodiments, when the power supply mode is AC power supply mode and the current AC power supply power is less than the preset limit power, the compressor is controlled to operate normally; When the power supply mode is AC power supply mode and the preset power limit is a preset value, the compressor is controlled to stop. When the power supply mode is AC power supply mode and the current AC power supply power is greater than the preset limit power, the compressor is controlled to reduce the frequency at a preset frequency reduction rate until the current AC power supply power is equal to the preset limit power, wherein the compressor is reduced to a preset minimum operating frequency.

[0038] In response to AC power only, if the current AC power is less than the limit power, the compressor will operate normally; when the limit power is 0, the compressor will stop immediately; when the limit power is greater than 0, the compressor's minimum power will be reduced to the set minimum operating frequency.

[0039] If the current AC power is less than the limit power, it means that the AC power usage is within an acceptable range. The unit does not need to be specially adjusted and can continue to operate according to the normal operating logic to ensure that the unit can stably provide the required cooling and other services to the load.

[0040] When the power limit is set to 0, the unit is not allowed to use AC power. As a critical component of the unit, the compressor immediately shuts down, cutting off the AC power consumption path and thus restricting AC power usage.

[0041] When the power limit is greater than 0, it means that the unit is allowed to use a certain amount of AC power, but it needs to be controlled. At this time, the operation of the compressor is constrained, and its power is gradually reduced until the set minimum operating frequency is reached.

[0042] For example, if the power limit for a certain unit is set to 500W, and the current AC power is 400W, which is less than the power limit, the unit will operate normally. If the power limit is set to 0, the compressor will immediately stop. If the power limit is 300W, the compressor will reduce its frequency to the lowest operating frequency, maintaining basic unit operation while meeting power rationing requirements.

[0043] Under conditions where the AC power supply is relatively sufficient and does not exceed the set limits, the unit can operate smoothly according to the normal working process without interruption or abnormality due to power limitation issues, effectively ensuring the stability and continuity of the system. Setting a minimum operating frequency is to ensure the stability and reliability of the compressor when operating at low power, avoiding compressor failure or damage due to excessively low frequency, while also meeting the basic operating requirements of the unit to a certain extent.

[0044] In some embodiments, when the AC power supply is less than a first AC power threshold and the AC input detection signal indicates no AC input is detected, the compressor is determined to be in DC power supply mode. When the AC power is less than 200W and no AC input is detected, it is determined that only DC power is connected.

[0045] If no relevant signal for AC input is detected, the unit is not drawing power from the mains.

[0046] This application determines that when only DC power is connected, DC power is used to reduce energy waste during the conversion process and improve overall energy utilization efficiency.

[0047] In some embodiments, when the power supply mode is DC power supply mode, the AC power limiting function is turned off.

[0048] In response to DC power only, the power curtailment function is not implemented. A certain grid-connected / off-grid unit, when only DC power is connected, can provide a stable DC power supply to the unit under sufficient sunlight. Assume that the unit requires 1500W of power for normal operation, and the DC power provided by the photovoltaic panels is sufficient to meet this demand. If the power curtailment function is implemented, the power may be limited to a lower level, resulting in the unit being unable to provide sufficient cooling or heating to the indoor environment. Without the power curtailment function, the unit can fully utilize the DC power, operating stably at 1500W, providing a comfortable environment for users.

[0049] In this application, direct current (DC) is directly used by the unit without conversion, reducing energy loss during the conversion process. The unit can operate at its optimal state, converting all DC power into effective cooling or heating, avoiding energy waste and achieving efficient energy utilization.

[0050] In some embodiments, when the DC power supply voltage is not less than the first DC voltage threshold and the AC input detection signal indicates that AC input is detected, the compressor is determined to be in AC / DC hybrid power supply mode.

[0051] If AC input is detected and the AC voltage is greater than 45V, then both AC and DC power are connected.

[0052] In some embodiments, the power limitation percentage and the rated power of the unit are received by the host computer or controller; the rated power of the unit is multiplied by the power limitation percentage to obtain the preset power limitation.

[0053] The power limit is calculated by multiplying the unit's rated power by a preset percentage. For example, if a grid-connected unit has a rated power of 2000W, and the preset percentage is set to 40% given the current high grid electricity price, then the power limit is 2000 × 40% = 800W. After the unit enters AC power limiting control mode, its operating status will be adjusted to not exceed 800W of AC power.

[0054] This application controls the compressor frequency to limit AC power usage and reduce electricity costs. When the mains electricity price fluctuates, a preset percentage is changed to adjust the power limit value, ensuring the unit always operates in the most economical state. This reduces electricity costs, improves energy efficiency, and promotes energy conservation and emission reduction.

[0055] In some embodiments, the compressor frequency is not adjusted within a 5% range above and below the power limit.

[0056] If the compressor frequency is adjusted due to a power deviation, resulting in frequent compressor start-stop or frequency-changing operation, it will not only shorten the compressor's lifespan and increase equipment wear, but also affect the overall stability and cooling effect of the unit. A buffer range of 5% above and below the power limit is set. Within this range, even if the current AC power deviates from the limit power, the control system will not adjust the compressor frequency. Only when the AC power exceeds this buffer range—that is, higher than 105% of the limit power or lower than 95% of the limit power—will the compressor frequency be adjusted accordingly based on the specific deviation and the predetermined control strategy.

[0057] For example, if the power limit of a certain unit is set to 1000W, then its buffer range is 950W to 1050W. If the current AC power is 980W, which is within this range, the compressor frequency remains unchanged; if the power becomes 1060W, exceeding the upper limit, the compressor frequency decreases; if the power drops to 940W, which is below the lower limit, the compressor frequency increases.

[0058] This application does not adjust the compressor frequency within the buffer zone. Only when the AC power exceeds this buffer range—that is, above 105% of the limit power or below 95% of the limit power—is the compressor frequency increased or decreased according to a predetermined control strategy. This effectively ensures the unit operates within a reasonable power range, reduces compressor operation, extends service life, reduces equipment wear, and simultaneously ensures the overall stability and cooling effect of the unit remain unaffected.

[0059] In some embodiments, when the power supply mode is AC / DC hybrid power supply mode and the current AC power supply is less than the preset limit power, the compressor is controlled to operate normally; When the power supply mode is AC / DC hybrid power supply mode, and the current AC power supply is greater than the preset limit power, the compressor is controlled to reduce the frequency at a preset frequency reduction rate until the current AC power supply is equal to the preset limit power, wherein the compressor is reduced to a preset minimum operating frequency. When the power supply mode is AC / DC hybrid power supply mode and the preset power limit is a preset value, if the compressor has dropped to the preset minimum operating frequency and the current AC power supply is greater than or equal to the protection power threshold and continues for a preset protection time, low-speed protection shutdown is executed.

[0060] In response to the simultaneous access of AC and DC power, if the current AC power is greater than the limit power, the compressor frequency is reduced at a rate of 1 Hz every 5 seconds until the current AC power and the limit power are equal; if the current AC power is less than the limit power, normal operation is maintained; when the limit power is greater than 0, the compressor's minimum power is reduced to the set minimum operating frequency.

[0061] Once the unit is determined to be connected to both AC and DC power, the control system immediately begins real-time monitoring of the current AC power and compares it meticulously with the pre-set power limit. The power limit is calculated based on the unit's rated power and the user-defined power restriction percentage, and represents a critical upper limit for AC power usage.

[0062] If monitoring detects that the current AC power exceeds the limit, the unit will activate the compressor frequency adjustment mechanism to avoid excessive AC power consumption and increased electricity costs. Specifically, the compressor's operating frequency will be gradually reduced at a stable rate of 1 Hz every 5 seconds until the current AC power drops to equal the limit.

[0063] If the current AC power is less than the limit power, it indicates that the AC power usage is within a reasonable range. At this time, the unit does not need to make special adjustments to the compressor frequency and can maintain normal operation to ensure that the unit can stably provide the required cooling and other services to the load.

[0064] When the power limit is greater than 0, in order to ensure the stable operation of the unit in the power-limiting mode and to prevent the compressor from being damaged due to excessively low power, the minimum power of the compressor is reduced to the set minimum operating frequency.

[0065] For example, a grid-connected or off-grid unit has a rated power of 2000W, and the user sets the power limiting percentage to 30%, then the limited power is 600W. If the current AC power is 700W, which is greater than the limited power, the compressor will reduce its frequency by 1 Hz every 5 seconds until the power drops to 600W; if the current power is 500W, which is less than the limited power, the unit will operate normally; if the limited power is 600W, the compressor will reduce its frequency to the set minimum operating frequency.

[0066] When the AC power is detected to be greater than the limit, the system gradually reduces the compressor frequency by 1 Hz every 5 seconds, avoiding sudden changes in compressor frequency. During the adjustment process, the unit's cooling or heating performance does not fluctuate significantly. When the current AC power is less than the limit, and the AC power supply is relatively sufficient and does not exceed the set limit, the unit fully utilizes the energy advantages of both AC and DC power. When the limit power is greater than 0, the compressor's minimum power is reduced to the set minimum operating frequency to meet the most basic cooling or heating needs.

[0067] This application proposes an AC power limiting control device for on-grid and off-grid chiller units, including: The data acquisition module is used to acquire the DC power supply voltage, AC input detection signal and current AC power supply of the refrigeration unit, and to obtain the power supply mode of the compressor based on the DC power supply voltage, AC input detection signal and current AC power supply. The power supply mode of the compressor includes AC power supply mode, DC power supply mode and AC / DC hybrid power supply mode. An AC power limiting module is used to activate the AC power limiting function according to the power supply mode. The frequency reduction module is used to control the compressor to reduce the frequency at a preset frequency reduction rate when the power supply mode is AC power supply mode or AC / DC hybrid power supply mode and the AC power supply power is greater than the preset limit power, until the current AC power supply power is equal to the preset limit power.

[0068] This application proposes application scenarios for AC power limiting control devices for on-grid and off-grid chiller units. Please refer to [link / reference]. Figure 2 It includes: working unit 1, photovoltaic panel 2, DC circuit breaker 3, AC circuit breaker 4, mains power 5, and controller; The output terminal of photovoltaic panel 2 is connected to the DC power supply input terminal of working unit 1 through DC circuit breaker 3; The AC power input terminal 5 is connected to the AC power input terminal of the working unit 1 through the AC circuit breaker 4; The controller is connected to the compressor drive module, DC power supply voltage detection terminal, AC input detection terminal and AC power supply detection terminal of the working unit 1 respectively; The controller also communicates with a host computer to receive AC power limiting commands and power limiting percentages.

[0069] This device is a power supply unit for a refrigeration unit that combines photovoltaic power generation and mains power supply. When there is sufficient sunlight, the photovoltaic panel 2 efficiently converts sunlight into direct current (DC). At this time, the DC power is transmitted through wires to the DC circuit breaker 3, which is in the conducting state to ensure that the current can pass smoothly. Subsequently, the DC power is directly connected to the working unit 1, providing the necessary electrical energy for the operation of the refrigeration unit, driving the refrigeration unit to perform operations such as water heating or cooling, thus realizing the use of clean solar energy resources to meet the energy needs of the refrigeration unit. The working unit 1 can be the refrigeration unit itself.

[0070] In cases of insufficient sunlight, such as at night or on cloudy days, photovoltaic panel 2 may not generate enough electricity or may not generate any electricity at all. In this case, the system switches to mains power supply mode. The AC power from mains 5 is connected through AC circuit breaker 4 to deliver AC power to the working unit 1, ensuring that the working unit 1 can continue to operate stably even when solar energy is lacking, thus meeting the user's needs for hot water or heating and cooling.

[0071] When photovoltaic power generation is unstable, sometimes sufficient and sometimes insufficient, the system operates in a hybrid power supply or flexible switching state. If photovoltaic power generation can partially meet the needs of the chiller unit, the DC circuit breaker 3 remains on, and photovoltaic power is used preferentially. The insufficient portion is supplemented by the mains power 5 through the AC circuit breaker 4. If photovoltaic power generation fluctuates, the system can intelligently adjust the power supply based on the actual situation, using the unit's internal MPPT. If the DC power is insufficient, it is supplemented by AC power. The circuit breakers on the power supply are always on, seamlessly switching between photovoltaic power supply and mains power supply to ensure that the chiller unit always receives a stable and reliable power supply and maintains normal operation.

[0072] In some embodiments, when the chiller unit is not connected to an AC power source, the chiller unit operates off-grid, and the photovoltaic panel 2 converts solar energy into DC power, which drives the chiller unit to operate. When both AC and DC power supplies are connected, DC power should be used preferentially.

[0073] Under sufficient sunlight, photovoltaic panels can continuously and efficiently convert solar energy into direct current (DC). Only when the photovoltaic power generation is insufficient to meet the operating requirements of the chiller unit will the system automatically switch to AC power for supplementary supply, ensuring the continuous and stable operation of the chiller unit and achieving a dual guarantee of reliable and environmentally friendly energy supply.

[0074] The variable frequency air conditioner provided in this application includes the AC power limiting control device for on-grid and off-grid chiller units described in the above embodiments, or, when performing power supply control, adopts the AC power limiting control method for on-grid and off-grid chiller units described in the above embodiments.

[0075] Based on the same inventive concept, according to another aspect of this application, such as Figure 3 As shown, embodiments of this application also provide a computer device 30, which includes a processor 310 and a memory 320. The memory 320 stores a computer program 321 that can run on the processor. When the processor 310 executes the program, it performs the steps of the method described above.

[0076] Based on the same inventive concept, according to another aspect of this application, such as Figure 4 As shown, embodiments of this application also provide a computer-readable storage medium 40, which stores a computer program 410 that, when executed by a processor, performs the methods described above.

[0077] Embodiments of this application may also include corresponding computer devices. The computer device includes a memory, at least one processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes any of the methods described above when executing the program.

[0078] The memory, as a non-volatile computer-readable storage medium, can be used to store non-volatile software programs, non-volatile computer-executable programs, and modules, such as program instructions / modules in the embodiments of this application. The processor executes various functional applications and data processing of the device by running the non-volatile software programs, instructions, and modules stored in the memory, thereby implementing the above-described method.

[0079] The memory may include a program storage area and a data storage area. The program storage area may store the operating system and applications required for at least one function; the data storage area may store data created based on the use of the device. Furthermore, the memory may include high-speed random access memory and non-volatile memory, such as at least one disk storage device, flash memory device, or other non-volatile solid-state storage device. In embodiments, the memory may optionally include memory remotely located relative to the processor, which can be connected to the local module via a network. Examples of such networks include, but are not limited to, the Internet, corporate intranets, local area networks, mobile communication networks, and combinations thereof.

[0080] Finally, it should be noted that those skilled in the art will understand that all or part of the processes in the above embodiments can be implemented by a computer program instructing related hardware. The program can be stored in a computer-readable storage medium, and when executed, it can include the processes of the embodiments of the methods described above. The storage medium for the program can be a magnetic disk, optical disk, read-only memory (ROM), or random access memory (RAM), etc. The above computer program embodiments can achieve the same or similar effects as any of the corresponding foregoing method embodiments.

[0081] Those skilled in the art will also understand that the various exemplary logic blocks, modules, circuits, and algorithm steps described in conjunction with the disclosure herein can be implemented as electronic hardware, computer software, or a combination of both. To clearly illustrate this interchangeability between hardware and software, the functionality of the various illustrative components, blocks, modules, circuits, and steps has been generally described. Whether this functionality is implemented as software or hardware depends on the specific application and the design constraints imposed on the system as a whole. Those skilled in the art can implement the functionality in various ways for each specific application, but such implementation decisions should not be construed as departing from the scope of the embodiments disclosed in this application.

[0082] The above are exemplary embodiments disclosed in this application. However, it should be noted that various changes and modifications can be made without departing from the scope of the embodiments disclosed in this application as defined by the claims. The functions, steps, and / or actions of the methods according to the disclosed embodiments described herein do not need to be performed in any particular order. The sequence numbers of the embodiments disclosed in this application are merely for descriptive purposes and do not represent the superiority or inferiority of the embodiments. Furthermore, although the elements disclosed in the embodiments of this application may be described or claimed individually, they may be understood as multiple unless explicitly limited to a singular number.

[0083] It should be understood that, as used herein, the singular form “a” is intended to include the plural form as well, unless the context clearly supports an exception. It should also be understood that, as used herein, “and / or” refers to any and all possible combinations of one or more of the associated listed items.

[0084] Those skilled in the art should understand that the discussion of any of the above embodiments is merely exemplary and is not intended to imply that the scope of the disclosure of the embodiments of this application (including the claims) is limited to these examples; under the concept of the embodiments of this application, the technical features of the above embodiments or different embodiments can also be combined, and there are many other variations of different aspects of the embodiments of this application as described above, which are not provided in detail for the sake of brevity. Therefore, any omissions, modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the embodiments of this application should be included within the protection scope of the embodiments of this application.

Claims

1. An AC power limiting control method for on-grid and off-grid chiller units, characterized in that, include: The DC power supply voltage, AC input detection signal, and current AC power supply of the refrigeration unit are obtained. Based on the DC power supply voltage, AC input detection signal, and current AC power supply, the power supply mode of the compressor is obtained. The power supply mode of the compressor includes AC power supply mode, DC power supply mode, and AC / DC hybrid power supply mode. Activate AC power limiting function according to the power supply mode; When the power supply mode is AC power supply mode or AC / DC hybrid power supply mode, and the AC power supply power is greater than the preset limit power, the compressor is controlled to reduce the frequency at a preset frequency reduction rate until the current AC power supply power is equal to the preset limit power.

2. The AC power limiting control method for grid-connected and off-grid chiller units according to claim 1, characterized in that, When the DC power supply voltage is less than the first DC voltage threshold and the AC input detection signal indicates that AC input is detected, it is determined that the compressor is currently in AC power supply mode.

3. The AC power limiting control method for grid-connected and off-grid chiller units according to claim 2, characterized in that, When the power supply mode is AC power supply mode and the current AC power supply power is less than the preset limit power, the compressor is controlled to operate normally; When the power supply mode is AC power supply mode and the preset power limit is a preset value, the compressor is controlled to stop. When the power supply mode is AC power supply mode and the current AC power supply power is greater than the preset limit power, the compressor is controlled to reduce the frequency at a preset frequency reduction rate until the current AC power supply power is equal to the preset limit power, wherein the compressor is reduced to a preset minimum operating frequency.

4. The AC power limiting control method for grid-connected and off-grid chiller units according to claim 1, characterized in that, When the AC power supply is less than the first AC power threshold and the AC input detection signal indicates that no AC input has been detected, the compressor is determined to be in DC power supply mode.

5. The AC power limiting control method for grid-connected and off-grid chiller units according to claim 4, characterized in that, When the power supply mode is DC power supply mode, the AC power limiting function is turned off.

6. The AC power limiting control method for grid-connected and off-grid chiller units according to claim 1, characterized in that, When the DC power supply voltage is not less than the first DC voltage threshold and the AC input detection signal indicates that AC input is detected, the compressor is determined to be in AC / DC hybrid power supply mode.

7. The AC power limiting control method for grid-connected and off-grid chiller units according to claim 1, characterized in that, The method also includes: Receive the power limiting percentage and rated power of the unit set by the host computer or controller; The preset power limit is obtained by multiplying the rated power of the unit by the power restriction percentage.

8. The AC power limiting control method for grid-connected and off-grid chiller units according to claim 1, characterized in that, When the power supply mode is AC / DC hybrid power supply mode, and the current AC power supply is less than the preset limit power, the compressor is controlled to operate normally; When the power supply mode is AC / DC hybrid power supply mode, and the current AC power supply is greater than the preset limit power, the compressor is controlled to reduce the frequency at a preset frequency reduction rate until the current AC power supply is equal to the preset limit power, wherein the compressor is reduced to a preset minimum operating frequency. When the power supply mode is AC / DC hybrid power supply mode and the preset power limit is a preset value, if the compressor has dropped to the preset minimum operating frequency and the current AC power supply is greater than or equal to the protection power threshold and continues for a preset protection time, low-speed protection shutdown is executed.

9. An AC power limiting control device for on-grid and off-grid refrigeration units, characterized in that, include: The data acquisition module is used to acquire the DC power supply voltage, AC input detection signal and current AC power supply of the refrigeration unit, and to obtain the power supply mode of the compressor based on the DC power supply voltage, AC input detection signal and current AC power supply. The power supply mode of the compressor includes AC power supply mode, DC power supply mode and AC / DC hybrid power supply mode. An AC power limiting module is used to activate the AC power limiting function according to the power supply mode. The frequency reduction module is used to control the compressor to reduce the frequency at a preset frequency reduction rate when the power supply mode is AC power supply mode or AC / DC hybrid power supply mode and the AC power supply power is greater than the preset limit power, until the current AC power supply power is equal to the preset limit power.

10. A variable frequency air conditioner, characterized in that, include: The AC power limiting control device for on-grid and off-grid chiller units as described in claim 9, or when performing power supply control, adopts the AC power limiting control method for on-grid and off-grid chiller units as described in any one of claims 1-8.

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