Photovoltaic direct-drive off-grid variable frequency heat pump air conditioner

Abstract

The present application relates to new energy heat pump and photovoltaic direct drive technical field, concretely is a kind of photovoltaic direct drive off-grid type variable frequency heat pump air conditioner, system includes: energy acquisition module, circulating module, selected charging module, discharging module and power supply module.In the present application, by collecting photovoltaic voltage, current and bus voltage, calculate photovoltaic input power and generate power supply state, can convert irradiation fluctuation into power supply judgment basis, by collecting compressor frequency, inside and outside fan speed and four-way reversing valve holding current, find out heat pump operation bottom power, can determine the running bottom line load, by comparing the difference between the remaining electricity, bus voltage and undervoltage threshold, can constrain energy storage charging opportunity, reduce bus collapse risk, by bus voltage drop, battery charge, energy storage end voltage and allowable discharge current to judge discharge state, and compare power supply gap power and battery maximum discharge power, can improve dispatching stability, energy storage protection and compressor operation reliability.

Description

Technical Field

[0001] This invention relates to the field of new energy heat pump and photovoltaic direct drive technology, and in particular to a photovoltaic direct drive off-grid inverter heat pump air conditioner. Background Technology

[0002] The field of new energy heat pump and photovoltaic direct drive application technology involves core aspects such as solar photovoltaic power generation, DC power supply and distribution, energy storage battery charging and discharging, heat pump cooling and heating cycle and variable frequency drive control. It uses photovoltaic modules to obtain solar radiation and output DC power, which is distributed through DC bus, battery pack, charge and discharge controller and variable frequency drive. The refrigerant circulation and air heat exchange process is participated by DC variable frequency compressor, four-way reversing valve, electronic expansion valve, indoor heat exchanger, outdoor heat exchanger, indoor DC fan and outdoor DC fan. Traditional inverter heat pump air conditioners rely on 220V or 380V AC power from the mains, which is rectified and converted into DC power by the main control board and inverter driver to drive the DC inverter compressor, indoor fan, and outdoor fan. The cooling or heating cycle is completed by the compressor compressing the refrigerant, the four-way reversing valve switching the refrigerant flow direction, the throttling device reducing the refrigerant pressure, and the indoor and outdoor heat exchangers exchanging heat. For the power supply and continuous operation of inverter heat pump air conditioners in places without AC mains power supply, an off-grid photovoltaic direct-drive inverter heat pump air conditioner system is constructed by combining photovoltaic modules, battery packs, DC bus, charge and discharge controller, inverter driver, and heat pump refrigerant circulation components.

[0003] Current technologies focus on connecting photovoltaics, batteries, busbars, controllers, drivers, and heat pump cycle components into a power supply chain. During operation, decisions are often based on device rated parameters, simple voltage thresholds, or conventional charge / discharge control, making it difficult to incorporate instantaneous photovoltaic input capacity, heat pump operating power, bus voltage trends, and battery discharge capacity into a single power cost assessment. When solar irradiance suddenly drops or the compressor frequency increases, the bus voltage may decline rapidly. If the charging channel remains open according to battery demand, the power absorbed by the energy storage side will crowd out the compressor drive power, causing the driver to shut down due to undervoltage or frequently restart. Under high-temperature cooling or low-temperature heating conditions, the loads of indoor and outdoor fans, four-way reversing valves, and compressors change simultaneously. Relying solely on bus voltage or battery charge is insufficient to distinguish between short-term fluctuations and sustained power shortages, easily leading to over-discharge of batteries, delayed mains power replenishment, and decreased heat pump output capacity. In off-grid scenarios, power supply continuity and equipment protection coordination are insufficient. Summary of the Invention

[0004] To address the technical problems existing in the prior art, this invention provides a photovoltaic direct-drive off-grid inverter heat pump air conditioner. The technical solution is as follows: On the one hand, a photovoltaic direct-drive off-grid inverter heat pump air conditioner is provided, including: The energy acquisition module collects the output voltage and current values ​​of the photovoltaic modules and the current voltage value of the DC bus, calculates the product of voltage and current to obtain the photovoltaic input power value, and generates the DC power supply status by combining the bus voltage. Based on the DC power supply status, the circulation module collects the frequency value of the DC inverter compressor, the speed value of the indoor circulating fan, the speed value of the outdoor circulating fan, and the holding current value of the four-way reversing valve, calculates the corresponding power, and obtains the minimum operating power of the heat pump. The selective charging module calculates the difference between the photovoltaic input power value and the heat pump's guaranteed operating power based on the heat pump's operating minimum power and the DC power supply status, obtains the operating minimum remaining power difference, collects the current DC bus voltage value, detects the compressor driver undervoltage protection threshold as the undervoltage threshold, compares the operating minimum remaining power difference, the current DC bus voltage value, and the undervoltage threshold, and generates the energy storage charging channel status. The discharge module collects the percentage of charge of the energy storage battery pack, the energy storage terminal voltage, the allowable discharge current, and the current DC bus voltage in the photovoltaic direct-drive off-grid inverter heat pump air conditioner based on the guaranteed operating power of the heat pump and the status of the energy storage charging channel. It also reads the DC bus voltage value of the previous control cycle in the operation record area of ​​the photovoltaic direct-drive off-grid inverter heat pump air conditioner, calculates the difference between the current DC bus voltage value and the DC bus voltage value of the previous control cycle, determines the DC bus voltage protection range in which the bus voltage drop amplitude is located and the battery charge state range in which the percentage of charge of the energy storage is located, and generates the energy storage discharge operation status. The power replenishment module detects the mains voltage according to the energy storage discharge operation status and the heat pump operation minimum power, calculates the power supply gap power and the battery maximum discharge power, compares the battery maximum discharge power and the power supply gap power, and obtains the air conditioning power supply scheduling command.

[0005] As a further aspect of the present invention, the DC power supply states include a sufficient power supply state, a critical power supply state, and a low-voltage power supply state; the guaranteed power for heat pump operation includes the guaranteed power for the compressor, the guaranteed power for indoor unit air supply, the guaranteed power for outdoor unit heat exchange, and the guaranteed power for valve maintenance; the energy storage charging channel states include a charging permitted state, a charging current limiting state, and a charging prohibited state; the energy storage discharging operation states include a discharging supported state, a discharging derating state, and a discharging cutoff state; and the air conditioning power supply scheduling commands include photovoltaic direct supply commands, energy storage compensation commands, mains power supplementation commands, and load power reduction commands.

[0006] As a further aspect of the present invention, the determination of the DC bus voltage protection range where the bus voltage drop amplitude is located and the battery state of charge range where the energy storage charge percentage is located, and the generation of energy storage discharge operation status, includes dividing the current DC bus voltage value into three DC bus voltage protection ranges: below the undervoltage threshold, equal to the undervoltage threshold, and above the undervoltage threshold, using the undervoltage threshold as a comparison benchmark.

[0007] As a further aspect of the present invention, the percentage of charge of the energy storage battery pack is divided into a zero range, a range greater than zero and less than 20%, a range of 20% to 80%, and a range greater than 80%.

[0008] As a further aspect of the present invention, the energy harvesting module includes: The electrical parameter acquisition submodule acquires the output voltage, output current and current DC bus voltage of the photovoltaic module in the photovoltaic direct-drive off-grid variable frequency heat pump air conditioner, monitors the writing status of the voltage channel, current channel and DC bus channel in the sampling buffer, verifies the channel data ownership relationship according to the sampling time sequence, writes the verification mark to the end of the data, and generates an electrical sampling vector. The power evaluation submodule calls the power sampling vector, reads the output voltage value according to the voltage channel, reads the output current value according to the current channel, reads data within the same sampling time sequence, calculates the photovoltaic input power value, writes the power data into the corresponding register bit, and binds the verification flag to the power register bit to obtain the photovoltaic input power; The power generation submodule reads the current DC bus voltage value based on the power sampling vector, calls the photovoltaic input power, detects the bus voltage access threshold and input power access threshold in the control register, determines the access status corresponding to the current DC bus voltage value and photovoltaic input power value, writes the determination flag into the power supply status bit, and generates the DC power supply status.

[0009] As a further aspect of the present invention, the loop module includes: Based on the DC power supply status, the status access submodule collects the frequency value of the DC inverter compressor, the speed value of the indoor circulating fan, the speed value of the outdoor circulating fan, and the holding current value of the four-way reversing valve. It monitors the channel writing status in the operation sampling buffer area, determines the relationship between the operation data and the DC power supply status according to the sampling timing, and generates an operation condition vector. The power mapping submodule calls the operating condition vector, reads the operating permit identifier according to the DC power supply status, detects the power mapping table in the drive register area, and calculates the component power value for the DC inverter compressor frequency value, indoor circulating fan speed value, outdoor circulating fan speed value, and four-way reversing valve holding current value to obtain the component power sequence. The minimum power guarantee submodule, based on the component power sequence, calls the sampling timing identifier in the operating condition vector, reads the operating permit identifier according to the DC power supply status, monitors the write status of the minimum power guarantee register area, calculates the corresponding power sum for the component power sequence values ​​within the same sampling timing, and obtains the minimum power guarantee for heat pump operation.

[0010] As a further aspect of the present invention, the optional filling module includes: The residual power calculation submodule calls the heat pump's guaranteed operating power and the DC power supply status, calls the photovoltaic input power value, reads the power supply permit identifier according to the DC power supply status, calculates the residual power difference for the guaranteed operating power for the photovoltaic input power value and the heat pump's guaranteed operating power under the same sampling time sequence, writes the residual power identifier into the residual power register, and obtains the residual power difference for the guaranteed operating power. The threshold comparison submodule collects the current DC bus voltage value based on the operating backup power difference, detects the compressor driver undervoltage protection threshold, reads the power supply permission identifier according to the DC power supply status, compares the current DC bus voltage value with the compressor driver undervoltage protection threshold for the access relationship, writes the access identifier into the voltage determination register, and generates the bus voltage access value. The channel determination submodule calls the bus voltage access value and the operating backup power difference, reads the power supply permit identifier according to the DC power supply status, monitors the channel writing status of the charging control register area, determines the channel access relationship corresponding to the operating backup power difference, bus voltage access value and power supply permit identifier, writes the channel identifier into the energy storage charging control bit, and generates the energy storage charging channel status.

[0011] As a further aspect of the present invention, the discharge module includes: The discharge acquisition submodule acquires the percentage of charge of the energy storage battery pack, the voltage value of the energy storage terminal, the allowable discharge current value of the energy storage and the current voltage value of the DC bus based on the guaranteed power of the heat pump and the status of the energy storage charging channel. It also monitors the writing status of the discharge sampling buffer channel, determines the relationship between the sampling timing and the operating status, and generates the energy storage operation vector. The voltage drop calculation submodule calls the energy storage operation vector, reads the DC bus voltage value of the previous control cycle in the operation record area of ​​the photovoltaic direct-drive off-grid variable frequency heat pump air conditioner, extracts the current DC bus voltage value according to the sampling time sequence, calculates the bus voltage drop amplitude value for the bus voltage data in the same control cycle link, and obtains the bus voltage drop amplitude. The status determination submodule, based on the bus voltage drop amplitude, calls the energy storage battery pack charge percentage in the energy storage operation vector, detects the DC bus voltage protection range and battery charge state interval, reads the channel status identifier according to the energy storage charging channel status, determines the discharge access relationship, and generates the energy storage discharge operation status.

[0012] As a further aspect of the present invention, the power replenishment module includes: The mains power detection submodule detects the effective voltage value of the AC mains power input terminal for the energy storage discharge operation status and the heat pump operation backup power, monitors the writing status of the supplementary power sampling buffer channel, and generates the mains power access status based on the sampling timing sequence associated with the energy storage discharge operation status, the heat pump operation backup power and the effective voltage value of the AC mains power input terminal. The gap calculation submodule calls the mains access status, reads the discharge permit identifier according to the energy storage discharge operation status, calculates the power supply gap power value and the maximum battery discharge power value based on the heat pump operation minimum power and the effective voltage value of the AC mains input terminal, writes the two power data into the power replenishment register area, and obtains the power replenishment comparison value. Based on the supplementary power comparison value, the scheduling generation submodule calls the mains power access status, reads the discharge permission identifier according to the energy storage discharge operation status, compares the scheduling access relationship between the battery maximum discharge power value and the power supply gap power value, writes the mains power access status value and the scheduling access relationship into the power supply scheduling register, and obtains the air conditioning power supply scheduling instruction.

[0013] As a further aspect of the present invention, when the current voltage value of the DC bus is lower than the undervoltage threshold and the charge percentage of the energy storage battery pack is in the range of 20% to 80% or greater than 80%, the allowable discharge current value of the energy storage and the voltage value of the energy storage terminal are used as input quantities to generate the energy storage discharge operation state.

[0014] Compared with the prior art, the advantages and positive effects of the present invention are as follows: In this invention, by collecting photovoltaic voltage, current, and bus voltage, calculating photovoltaic input power, and generating power supply status, irradiance fluctuations can be transformed into a basis for power supply judgment. By collecting compressor frequency, internal and external fan speeds, and four-way reversing valve holding current, the minimum operating power of the heat pump can be determined, thus clarifying the operating baseline load. By comparing the residual power difference, bus voltage, and undervoltage threshold, the timing of energy storage charging can be constrained, reducing the risk of bus collapse. By judging the discharge status through bus voltage drop, battery charge, energy storage terminal voltage, and allowable discharge current, and comparing the power supply gap power with the battery's maximum discharge power, dispatch stability, energy storage protection, and compressor operation reliability can be improved. Attached Figure Description

[0015] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0016] Figure 1 This is a system flowchart of the present invention; Figure 2 This is a system block diagram of the present invention; Figure 3 This is a flowchart of the energy harvesting module in this invention; Figure 4 This is a flowchart of the loop module in this invention; Figure 5 This is a flowchart of the optional charging module in this invention; Figure 6 This is a flowchart of the discharge module in this invention; Figure 7 This is a flowchart of the power replenishment module in this invention. Detailed Implementation

[0017] The technical solution of the present invention will now be described with reference to the accompanying drawings.

[0018] This invention provides a photovoltaic direct-drive off-grid inverter heat pump air conditioner, such as... Figure 1-2 The diagram shown illustrates a photovoltaic direct-drive off-grid inverter heat pump air conditioner system, which includes: The energy acquisition module collects the output voltage and current values ​​of the photovoltaic modules and the current DC bus voltage value in the photovoltaic direct-drive off-grid inverter heat pump air conditioner. It calculates the product of the output voltage and current values ​​to obtain the photovoltaic input power value and generates the DC power supply status by combining the current DC bus voltage value. Based on the DC power supply status, the circulation module collects the frequency value of the DC inverter compressor, the speed value of the indoor circulating fan, the speed value of the outdoor circulating fan, and the holding current value of the four-way reversing valve, calculates the corresponding power, and obtains the minimum operating power of the heat pump. The selective charging module calculates the difference between the photovoltaic input power and the heat pump's guaranteed operating power based on the heat pump's operating minimum power and DC power supply status, obtains the operating minimum power reserve difference, collects the current DC bus voltage value, and detects the compressor driver undervoltage protection threshold as the undervoltage threshold. It then compares the operating minimum power reserve difference, the current DC bus voltage value, and the undervoltage threshold to generate the energy storage charging channel status. The discharge module collects the percentage of charge of the energy storage battery pack, the energy storage terminal voltage, the allowable discharge current value of energy storage, and the current DC bus voltage value in the photovoltaic direct-drive off-grid inverter heat pump air conditioner based on the guaranteed power of the heat pump operation and the status of the energy storage charging channel. It also reads the DC bus voltage value of the previous control cycle from the machine's operation record area, calculates the difference between the current DC bus voltage value and the DC bus voltage value of the previous control cycle, determines the DC bus voltage protection range in which the bus voltage drop amplitude is located and the battery charge state range in which the percentage of energy storage charge is located, and generates the energy storage discharge operation status. The power replenishment module detects the effective voltage value at the AC mains input terminal, calculates the power supply gap value and the maximum discharge power value of the battery, and compares the maximum discharge power value of the battery with the power supply gap value to obtain the air conditioning power supply scheduling command.

[0019] DC power supply status includes sufficient power supply, critical power supply, and undervoltage power supply; heat pump operation minimum power includes compressor minimum power, indoor unit air supply minimum power, outdoor unit heat exchange minimum power, and valve maintenance minimum power; energy storage charging channel status includes charging permitted status, charging current limiting status, and charging prohibited status; energy storage discharge operation status includes discharge supported status, discharge derating status, and discharge cutoff status; air conditioning power supply dispatch instructions include photovoltaic direct supply instructions, energy storage compensation instructions, mains power supplement instructions, and load power reduction instructions.

[0020] Specifically, such as Figure 2 , 3 As shown, the energy harvesting module includes: The electrical parameter acquisition submodule acquires the output voltage and current values ​​of the photovoltaic modules and the current DC bus voltage value in the photovoltaic direct-drive off-grid variable frequency heat pump air conditioner. It monitors the writing status of the voltage channel, current channel and bus channel in the sampling buffer area, verifies the channel data ownership relationship according to the sampling time sequence, writes the verification identifier to the end of the data, and generates an electrical energy sampling vector. Within each sampling period, the output voltage value of the photovoltaic module, the output current value, and the current DC bus voltage value are received sequentially. The sampling period is set to 100 milliseconds. The sampling buffer is configured with consecutive register bits for voltage, current, and bus channels. After each channel is written, the write timestamp is read first. If the timestamp difference is no more than 5 milliseconds, it is classified as the same sampling sequence number. If it exceeds 5 milliseconds, the earlier data is marked as lagging data and moved to the buffer bit to be reviewed. For the voltage channel, the median value of three consecutive samples is taken. For the current channel, reverse outliers less than 0 amps are removed. For the bus channel, spike values ​​with instantaneous jumps exceeding 15 volts are removed. For example, in sampling sequence 2307, the voltage channel reads 326.1V, 326.4V, and 326.7V sequentially, and writes 326.4V; the current channel reads 9.32A, 9.35A, and 9.38A sequentially, and writes 9.35A; the bus channel reads 323.6V, 323.8V, and 324.2V, and writes 323.8V. In sampling sequence 2314, the voltage value is written as 288.2V, the current value as 3.60A, and the bus value as 291.0V. The maximum power voltage of the photovoltaic module and the DC air conditioning input voltage range are calibrated according to the publicly available specifications. The module-side voltage values ​​fall within the allowable range for the project, and the DC input range is configured from 90V to 360V.

[0021] Table 1 Data Table of Electricity Sampling Implementation Table 1 lists the electrical parameter data for two continuous operation scenarios. The first set corresponds to the stable sunlight scenario, and the second set corresponds to the cloud shadow occlusion scenario.

[0022] The power evaluation submodule calls the power sampling vector, reads the output voltage value according to the voltage channel, reads the output current value according to the current channel, reads data within the same sampling time sequence, calculates the photovoltaic input power value, writes the power data into the corresponding register bit, and binds the verification flag to the power register bit to obtain the photovoltaic input power; The system reads the power sampling vector with the permission verification identifier. First, it locks the voltage and current channels according to the sampling sequence number, and then reads the range calibration coefficients for both data items. The voltage channel calibration coefficients are provided by the factory calibration record. The calibration record uses a 300V standard source for 10 consecutive samplings. When the average reading is 299.4V, the deviation compensation is written to the voltage correction register. The current channel calibration coefficients are obtained by using a 10A standard current source for 10 consecutive samplings. When the average reading is 9.96A, the deviation compensation is written to the current correction register. When calculating the photovoltaic input power value, the power evaluation submodule performs a product operation on the corrected output voltage value and output current value, and rounds the register bits in 1-watt increments. For example, in sampling sequence 2307, multiplying 326.4 volts and 9.35 amps yields a photovoltaic input power of 3051.8 watts, and the register bit is written with 3052 watts in 1-watt increments. In sampling sequence 2314, multiplying 288.2 volts and 3.60 amps yields a photovoltaic input power of 1037.5 watts, and the register bit is written with 1038 watts. After binding the power register bit with the sampling tail bit verification flag, if the verification flag is still allowed during subsequent readings, the power data corresponding to that sampling sequence number enters the power generation submodule; if any channel is marked as lagging, the corresponding power register bit is written with a freeze flag. The advantage of this calculation logic is that by binding the sampling sequence number, verification flag, and register bit together in the calculation, the power value and the electrical parameter source maintain the same sampling attribution. In 50 bench tests, the power attribution was correct in 48 groups using this binding method and in 42 groups using the fixed-sequence reading method, representing a 14.3% improvement over the fixed-sequence reading method.

[0023] The power generation submodule reads the current DC bus voltage value based on the power sampling vector, calls the photovoltaic input power, detects the bus voltage access threshold and input power access threshold in the control register, determines the access status corresponding to the current DC bus voltage value and photovoltaic input power value, writes the determination flag into the power supply status bit, and generates the DC power supply status. The bus voltage threshold is set to 300V, with a 5V margin above the compressor driver low-voltage protection setting of 295V. The input power threshold is set to 1800W, with the highest guaranteed power value of 1780W from the most recent 100 stable cooling samples plus a 20W sampling margin. During the judgment process, if the bus voltage reaches 300V and the photovoltaic input power reaches 1800W, the power supply status is set to "Power Supply Permitted"; if either value fails to meet the corresponding threshold, the power supply status is set to "Power Supply Prohibited". For example, in sampling number 2307, the current DC bus voltage of 323.8V and the photovoltaic input power of 3052W both meet the corresponding thresholds, generating a "Power Supply Permitted" status. In sampling number 2314, the current DC bus voltage of 291.0V and the photovoltaic input power of 1038W both fail to meet the corresponding thresholds, generating a "Power Supply Prohibited" status. Threshold verification involved recording 120 shading test bench switches. At a 300V threshold, there were 2 instances of false bus releases, and at a 295V threshold, there were 9. At an 1800W threshold, there was 1 compressor start-up failure, and at a 1600W threshold, there were 8. These experimental results indicate that the 300V and 1800W combination reduced the number of false releases by 77.8% compared to the lower threshold combination.

[0024] Specifically, such as Figure 2 , 4 As shown, the loop module includes: The status access submodule is based on the DC power supply status. It collects the frequency value of the DC inverter compressor, the speed value of the indoor circulating fan, the speed value of the outdoor circulating fan, and the holding current value of the four-way reversing valve. It monitors the channel writing status in the operation sampling buffer area, determines the relationship between the operation data and the DC power supply status based on the sampling timing, and generates an operation condition vector. The operation permit identifier is read based on the DC power supply status bit. Then, the same sampling sequence number is established for the DC inverter compressor frequency value, indoor circulating fan speed value, outdoor circulating fan speed value, and four-way reversing valve holding current value. The operation sampling buffer is configured with a frequency channel, an indoor fan channel, an outdoor fan channel, and a valve current channel. The sampling clock is recorded after writing to each channel. The frequency value is read back from the compressor drive register, and the unit is Hertz. The indoor and outdoor circulating fan speed values ​​are converted to revolutions per minute (RPM) from Hall effect pulse counts. The four-way reversing valve holding current value is converted to Amps from the voltage drop across the valve coil's series sampling resistor. The four-way reversing valve is used for switching between heating and cooling in the heat pump; in this embodiment, the valve current is only used for holding status identification. Sampling sequence 2307 reads the power supply permission flag, the compressor frequency is 55 Hz, the indoor circulating fan speed is 760 rpm, the outdoor circulating fan speed is 820 rpm, and the valve holding current is 0.21 A. Sampling sequence 2314 reads the power supply prohibition flag. Because the room temperature still needs to be maintained, the drive register reads back the compressor frequency as 75 Hz, the indoor circulating fan speed as 880 rpm, the outdoor circulating fan speed as 960 rpm, and the valve holding current as 0.21 A. If the difference between the running sampling timestamp and the DC power supply status timestamp does not exceed one sampling period, the same operating condition vector is written; if it exceeds one sampling period, the operating condition vector is written with an update pending flag.

[0025] The power mapping submodule calls the operating condition vector, reads the operating license identifier according to the DC power supply status, detects the power mapping table in the drive register area, and calculates the component power value for the DC inverter compressor frequency value, indoor circulating fan speed value, outdoor circulating fan speed value, and four-way reversing valve holding current value, and obtains the component power sequence. The mapping table is written from the factory bench calibration record. The compressor power is determined by the frequency range, the suction and discharge pressure difference range, and the drive current range. The indoor circulating fan power is determined by the speed range, the outdoor circulating fan power is determined by the speed range, and the four-way reversing valve power is determined by the holding current and the coil rated voltage. The fuzzy high and low ranges are quantified into clear levels in the register area: the compressor low frequency is 20 Hz to 40 Hz, the medium frequency is 41 Hz to 65 Hz, and the high frequency is 66 Hz to 90 Hz; the fan low speed is 300 rpm to 600 rpm, the medium speed is 601 rpm to 900 rpm, and the high speed is 901 rpm to 1200 rpm. For example, in sampling number 2307, 55 Hz is classified as medium frequency, 760 rpm and 820 rpm as medium speed. The power mapping table shows a compressor power of 1120 watts, an indoor circulating fan power of 38 watts, and an outdoor circulating fan power of 62 watts. The valve holding current of 0.21 amps is multiplied by the 24-volt coil voltage to obtain 5 watts. In sampling number 2314, 75 Hz is classified as high frequency, 880 rpm as medium speed upper limit, and 960 rpm as high speed. The power mapping table shows a compressor power of 1680 watts, an indoor circulating fan power of 50 watts, an outdoor circulating fan power of 78 watts, and the valve power is still 5 watts. Table 2 Power Mapping Table for Operating Conditions Table 2 shows the component mapping data under two sampling numbers, and each data point is directly entered into the component power sequence.

[0026] The minimum power guarantee summary submodule is based on the component power sequence, calls the sampling timing identifier in the operating condition vector, reads the operating permit identifier according to the DC power supply status, monitors the write status of the minimum power guarantee register area, calculates the corresponding power sum for the component power sequence values ​​within the same sampling timing, and obtains the minimum power guarantee for heat pump operation. When the register is idle, the compressor power is written first, followed by the indoor circulating fan power, outdoor circulating fan power, and four-way reversing valve power. When the register is occupied, the new sequence is placed in the next idle register row. The summary calculation uses a summation process, with participation limited to the four component power items under the same sampling number, and calls are not made across numbers. For example, in sampling number 2307, the aforementioned compressor power of 1120 watts, indoor circulating fan power of 38 watts, outdoor circulating fan power of 62 watts, and valve power of 5 watts are summed together to obtain a minimum operating power of 1225 watts for the heat pump; in sampling number 2314, the aforementioned compressor power of 1680 watts, indoor circulating fan power of 50 watts, outdoor circulating fan power of 78 watts, and valve power of 5 watts are summed together to obtain a minimum operating power of 1813 watts for the heat pump. When the operating permit identifier is "Power Supply Permit," the guaranteed power register area is written with a "Direct Drive Permit" mark; when the operating permit identifier is "Power Supply Prohibited," the guaranteed power register area is written with a "Power Required" mark. In 100 sampling tests, the average deviation between the power obtained by summarizing the power according to the same sampling sequence number and the measured value of the power meter was 24 watts, while the average deviation across different sampling sequences was 91 watts. This experimental result shows that summarizing according to the same sampling sequence number reduces the average deviation by 73.6% compared to summarizing across different sampling sequences.

[0027] Specifically, such as Figure 2 , 5 As shown, the optional charging module includes: The residual power calculation submodule calls the heat pump's guaranteed operating power and DC power supply status, calls the photovoltaic input power value, reads the power supply permit identifier according to the DC power supply status, calculates the residual power difference under the guaranteed operating power for the photovoltaic input power value and the heat pump's guaranteed operating power under the same sampling time sequence, writes the residual power identifier into the residual power register, and obtains the residual power difference under the guaranteed operating power. The residual power register is divided into three types of text identifiers: positive residual power, negative residual power, and frozen. Non-numerical identifiers are quantized into register area text codes before being written. Positive residual power corresponds to the rechargeable criterion, negative residual power corresponds to the non-rechargeable criterion, and frozen power corresponds to an abnormal sampling assignment. When calculating the difference in operating minimum residual power, the residual power calculation submodule performs a difference operation on the photovoltaic input power value and the heat pump operating minimum power value under the same sampling number. If the former value is higher, a positive residual power identifier is written; if the latter value is higher, a negative residual power identifier is written. For example, sampling number 2307, with the aforementioned photovoltaic input power of 3052 watts and heat pump operating minimum power of 1225 watts, yields an operating minimum residual power difference of 1827 watts, and the residual power identifier is written as positive. Sampling number 2314, with the photovoltaic input power of 1038 watts and heat pump operating minimum power of 1813 watts, yields an operating minimum residual power difference of -775 watts, and the residual power identifier is written as negative. The threshold for judging the remaining power difference is set at 300 watts. This threshold is obtained by adding a 60-watt bus fluctuation margin to the minimum stable charging power of the energy storage charger of 240 watts. When the remaining power difference reaches 300 watts, the charging access judgment is entered. When the remaining power difference is less than 300 watts, the charging channel is prohibited.

[0028] The threshold comparison submodule collects the current DC bus voltage value based on the operating backup power difference, detects the compressor driver undervoltage protection threshold, reads the power supply permission flag according to the DC power supply status, compares the current DC bus voltage value with the compressor driver undervoltage protection threshold for the access relationship, writes the access flag into the voltage judgment register, and generates the bus voltage access value. The undervoltage protection threshold is determined by the driver nameplate parameters and bench power-off records. In this embodiment, the driver experienced three torque fluctuations between 292V and 294V. No undervoltage shutdowns were recorded during 60 start-up tests above 295V; therefore, 295V was written to the register. The bus voltage threshold is written using a text status; a write voltage of 295V is allowed, and values ​​below 295V are not. For example, sampling number 2307 is input with the aforementioned current DC bus voltage of 323.8V, compared with 295V, and then the voltage is allowed. Simultaneously, the remaining operating power reserve of 1827W is included, retaining the charging qualification. Sampling number 2314 is input with the current DC bus voltage of 291.0V, compared with 295V, and then the voltage is not allowed. Simultaneously, the remaining operating power reserve of -775W is included, clearing the charging qualification. Threshold verification was performed using a 10-minute shading disturbance test, recording a total of 600 sampling points. Under the 295V threshold, the compressor shut down due to undervoltage 0 times; under the 290V threshold, it shut down due to undervoltage 5 times; and under the 300V threshold, it shut down prematurely 38 times. The experimental results show that the 295V threshold reduces undervoltage shutdowns by 5 times compared to the 290V threshold, and reduces premature charging shutdowns by 38 times compared to the 300V threshold.

[0029] The channel determination submodule calls the bus voltage access value and the operating backup power difference, reads the power supply permit identifier according to the DC power supply status, monitors the channel writing status of the charging control register area, determines the channel access relationship corresponding to the operating backup power difference, bus voltage access value and power supply permit identifier, writes the channel identifier into the energy storage charging control bit, and generates the energy storage charging channel status. The storage area uses three types of channel identifiers: charging permission, charging prohibition, and waiting for refresh. Before writing, the sampling sequence number of the three inputs is checked. During the determination, if the operating minimum remaining power difference reaches 300 watts, the bus voltage threshold is voltage threshold, and the power supply permission identifier is power supply permission, and all three are true simultaneously, charging permission is written; if any one of them is false, charging prohibition is written; if the sampling sequence number is inconsistent, waiting for refresh is written. For example, in sampling sequence number 2307, if the operating minimum remaining power difference is 1827 watts, reaching the 300-watt threshold, and the bus voltage of 323.8 volts has passed the 295-volt comparison, the power supply status is power supply permission, charging permission is written to the charging control bit, and the recommended charging power is limited to 1000 watts. This value is obtained by subtracting the 200-watt heat pump surge margin from the energy storage terminal's rated charging power of 1200 watts. Within sampling sequence 2314, the remaining power difference during operation was -775 watts, failing to reach the 300-watt threshold. The bus voltage of 291.0 volts failed the 295-volt comparison, resulting in a power supply prohibition status, and the charging control bit was written as "charging prohibited." The advantage of this operational logic lies in its combined determination based on three factors: remaining power difference, bus voltage access, and power supply permission. In 60 rapid cloud shadow occlusion tests, 8 instances of false charging occurred due to remaining power alone, while only 1 instance occurred due to the combined determination of all three factors, representing an 87.5% reduction in false charging compared to relying solely on remaining power.

[0030] Specifically, such as Figure 2 , 6 As shown, the discharge module includes: The discharge acquisition submodule collects the percentage of charge of the energy storage battery pack, the voltage value of the energy storage terminal, the allowable discharge current value of the energy storage, and the current voltage value of the DC bus based on the guaranteed power of the heat pump and the status of the energy storage charging channel. It also monitors the writing status of the discharge sampling buffer channel, determines the relationship between the sampling timing and the operating status, and generates the energy storage operation vector. The percentage of charge is given by the battery management board through cell voltage and cumulative current integration, and the reading is refreshed every 1 second; the energy storage terminal voltage value is obtained by voltage division sampling of the positive and negative terminals of the energy storage; the allowable discharge current value of the energy storage is output by the battery management board based on cell temperature, current percentage of charge, and protection status; the current DC bus voltage value follows the bus channel reading. The daily operating charge range of the lithium battery is configured from 20% to 90%, and in this embodiment, the lower discharge limit is written as 20%, and the upper charging limit is written as 90%. The aforementioned charging prohibition flag is included in the sampling sequence number 2314, and the battery pack charge percentage is read as 64%, the energy storage terminal voltage value is 256.8 volts, the allowable discharge current value is 2.4 amps, and the current DC bus voltage value is 291.0 volts. The discharge sampling buffer is written separately according to the charge channel, voltage channel, current channel, and bus channel. When the difference between the four timestamps does not exceed 20 milliseconds, they are grouped into the same energy storage operation vector. If the charging channel status is "charging permitted", the discharge acquisition submodule retains the data but writes a pre-discharge prohibition flag; if the charging channel status is "charging prohibited", a pre-discharge determination flag is written.

[0031] The voltage drop calculation submodule calls the energy storage operation vector, reads the DC bus voltage value of the previous control cycle in the local operation record area, extracts the current DC bus voltage value according to the sampling timing, calculates the bus voltage drop amplitude value for the bus voltage data in the same control cycle link, and obtains the bus voltage drop amplitude. The previous control cycle is determined by the most recently completed sampling sequence number. Sampling sequence number 2307 recorded a bus voltage value of 323.8 volts, and the current sampling sequence number 2314 recorded a bus voltage value of 291.0 volts. The bus voltage drop amplitude is derived by the difference between the bus voltages of two control cycles. A positive voltage drop is written when the previous cycle voltage is higher than the current voltage, and a negative voltage drop is written when the current voltage is higher than the previous cycle voltage. For example, substituting 323.8 volts and 291.0 volts into the difference calculation yields a bus voltage drop amplitude of 32.8 volts. The voltage drop threshold is set to 15 volts. This threshold was obtained from 100 light-shielding tests during compressor operation at 75 Hz. No torque fluctuations occurred when the bus voltage drop was less than 10 volts, and torque fluctuations were recorded 7 times when the bus voltage drop reached 15 volts or more. Therefore, 15 volts is written to the register. The current voltage drop of 32.8 volts is higher than the 15 volt threshold, and a discharge determination is written to the voltage drop status bit. The advantage of this operational logic is that it uses the bus voltage from the previous control cycle and the current bus voltage to participate in the difference determination; in 120 cloud shadow switching tests, the voltage drop determination identified insufficient power supply 116 times in advance, and the single-point voltage determination identified it 101 times, which is 14.9% higher than the single-point voltage determination.

[0032] The status determination submodule, based on the bus voltage drop amplitude, calls the energy storage battery pack charge percentage in the energy storage operation vector, detects the DC bus voltage protection range and battery charge state interval, reads the channel status identifier according to the energy storage charging channel status, determines the discharge access relationship, and generates the energy storage discharge operation status. The DC bus voltage protection range is defined as 285V to 360V. Below 285V, it is defined as bus protection; above 360V, it is defined as bus overvoltage protection. The battery state of charge range is defined as 20% to 90%. Below 20%, it is defined as battery low charge protection; above 90%, it is defined as battery high charge prohibition. Discharge access is determined by four criteria: a bus voltage drop of 15V, a battery charge percentage between 20% and 90%, a current DC bus voltage between 285V and 360V, and a charging prohibition status in the energy storage charging channel. For example, sampling number 2314, with the aforementioned bus voltage drop of 32.8V, battery charge percentage of 64%, current DC bus voltage of 291.0V, and charging prohibition flag, all four criteria are met, and the energy storage discharge operation status is defined as discharge permission. If the charge percentage reading is 18%, even if the bus voltage drop is still 32.8V, battery low charge protection is still defined. The judgment was correctly approved 77 times out of 80 discharge start-stop tests, and correctly approved 66 times for individual charge determination, which is an improvement of 16.7% compared to individual charge determination.

[0033] Specifically, such as Figure 2 , 7 As shown, the power replenishment module includes: The mains power detection submodule detects the effective voltage value of the AC mains power input terminal for the energy storage discharge operation status and the heat pump operation backup power, monitors the writing status of the supplementary power sampling buffer channel, and generates the mains power access status based on the sampling timing sequence related to the energy storage discharge operation status, the heat pump operation backup power, and the effective voltage value of the AC mains power input terminal. The effective AC voltage is obtained by collecting 40 instantaneous values ​​within 20 milliseconds from the mains sampling board, and then taking the square root of the average of the squared values. The sampling results are written into the mains voltage channel of the supplementary power sampling buffer. The mains access status uses four text states: effective access, undervoltage access, overvoltage access, and not accessed. For the 220V power supply port, the effective access range is written as 198V to 242V. Below 198V is written as undervoltage access, above 242V is written as overvoltage access, and less than 30V for three consecutive sampling periods is written as not accessed. For example, in sampling number 2314, the effective AC mains input voltage value is read as 223.6V. Comparing it with the 198V to 242V range, the mains access status is written as effective access. In the same sampling number, the aforementioned energy storage discharge operation status is read as discharge permitted, and the heat pump operation minimum power is 1813W. The timestamp difference of the three data items is less than 20 milliseconds, and the associated identifier is written as permitted. If an old value with the same sequence number already exists in the power-up sampling buffer, the old value will be overwritten with the most recently written data whose verification flag is allowed. In 50 plug-in / plug-out mains power tests, the effective voltage range was correctly determined 49 times, and the single instantaneous voltage was correctly determined 43 times, representing a 14.0% improvement compared to the single instantaneous voltage determination.

[0034] The gap calculation submodule calls the mains power access status, reads the discharge permit identifier according to the energy storage discharge operation status, calculates the power supply gap power value and the battery maximum discharge power value based on the heat pump operation minimum power and the effective voltage value of the AC mains input terminal, writes the two power data into the supplementary power register area, and obtains the supplementary power comparison value. The power supply gap value is obtained by the difference between the guaranteed operating power of the heat pump and the currently available photovoltaic input power. If the difference is negative, 0 watts is written; if the difference is positive, a positive gap power is written. The maximum battery discharge power value is obtained by multiplying the energy storage terminal voltage value and the energy storage allowable discharge current value, and is written into the power replenishment register in 1-watt increments. For example, in sampling number 2314, the aforementioned guaranteed operating power of the heat pump (1813 watts) and photovoltaic input power (1038 watts) are substituted to obtain a power supply gap power of 775 watts; simultaneously, the energy storage terminal voltage value (256.8 volts) and the energy storage allowable discharge current value (2.4 amps) are substituted to obtain a maximum battery discharge power of 616.3 watts, and 616 watts are written into the register. After the two power values ​​are written, the effective grid connection status and discharge permit identifier are jointly bound, and the gap difference is obtained by comparing 775 watts and 616 watts to obtain 159 watts, which is used as the grid power replenishment power registration value. The advantage of this calculation logic is that it uses the minimum operating power of the heat pump, the photovoltaic input power, the voltage value of the energy storage terminal, and the allowable discharge current value of the energy storage to participate in the power replenishment calculation. In 80 shading power replenishment tests, the average scheduling deviation of the linkage calculation was 32 watts, and the average scheduling deviation of the fixed battery power calculation was 118 watts, which is a decrease of 72.9% compared with the fixed battery power calculation.

[0035] The scheduling generation submodule, based on the supplementary power comparison value, calls the mains power access status, reads the discharge permit identifier according to the energy storage discharge operation status, compares the scheduling access relationship between the battery maximum discharge power value and the power supply gap power value, writes the mains power access status value and the scheduling access relationship into the power supply scheduling register, and obtains the air conditioning power supply scheduling instruction. When the battery's maximum discharge power reaches the power supply gap, the power supply dispatch register is written with energy storage to replenish it separately; when the battery's maximum discharge power is lower than the power supply gap and the mains power is effectively connected, it is written with both energy storage and mains power replenishing it together; when the battery's maximum discharge power is lower than the power supply gap and the mains power is not connected, undervoltage connected, or overvoltage connected, it is written with compressor frequency reduction pending energy replenishment. For example, sampling sequence number 2314 includes the aforementioned power supply gap power of 775 watts, battery maximum discharge power of 616 watts, mains power replenishment power of 159 watts, mains power effective connection status, and discharge permit identifier. The dispatch register is written with both energy storage and mains power replenishing it together. The air conditioning power supply dispatch instruction is recorded as 1038 watts supplied by the photovoltaic side, 616 watts supplied by the energy storage side, and 159 watts replenished by the mains side. After adjusting the three power values, the corresponding minimum operating power for the heat pump is 1813 watts. If the effective mains voltage drops to 184 volts, the same gap condition is written with compressor frequency reduction pending energy replenishment. Table 3. Comparison Test Results of Power Supply Dispatch Table 3 presents the test results of the embodiment. The experimental results show that the scheduling accuracy of the linkage scheme in this embodiment is 96.3%, while the scheduling accuracy of the fixed threshold scheme is 83.8%, which is 14.9% higher than that of the fixed threshold scheme.

[0036] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A photovoltaic direct-drive off-grid inverter heat pump air conditioner, characterized in that, The photovoltaic direct-drive off-grid inverter heat pump air conditioner includes: The energy acquisition module collects the output voltage and current values ​​of the photovoltaic modules and the current voltage value of the DC bus, calculates the product of voltage and current to obtain the photovoltaic input power value, and generates the DC power supply status by combining the bus voltage. Based on the DC power supply status, the circulation module collects the DC inverter compressor frequency value, indoor circulation fan speed value, outdoor circulation fan speed value, and four-way reversing valve holding current value, calculates the corresponding power, and obtains the minimum operating power of the heat pump. The selective charging module calculates the difference between the photovoltaic input power value and the heat pump's guaranteed operating power based on the heat pump's operating minimum power and the DC power supply status, obtains the operating minimum remaining power difference, collects the current DC bus voltage value, detects the compressor driver undervoltage protection threshold as the undervoltage threshold, compares the operating minimum remaining power difference, the current DC bus voltage value, and the undervoltage threshold, and generates the energy storage charging channel status. The discharge module collects the percentage of charge of the energy storage battery pack, the energy storage terminal voltage, the allowable discharge current, and the current DC bus voltage in the photovoltaic direct-drive off-grid inverter heat pump air conditioner based on the guaranteed operating power of the heat pump and the status of the energy storage charging channel. It also reads the DC bus voltage value of the previous control cycle in the operation record area of ​​the photovoltaic direct-drive off-grid inverter heat pump air conditioner, calculates the difference between the current DC bus voltage value and the DC bus voltage value of the previous control cycle, determines the DC bus voltage protection range in which the bus voltage drop amplitude is located and the battery charge state range in which the percentage of charge of the energy storage is located, and generates the energy storage discharge operation status. The power replenishment module detects the mains voltage according to the energy storage discharge operation status and the heat pump operation minimum power, calculates the power supply gap power and the battery maximum discharge power, compares the battery maximum discharge power and the power supply gap power, and obtains the air conditioning power supply scheduling command.

2. The photovoltaic direct-drive off-grid inverter heat pump air conditioner according to claim 1, characterized in that: The DC power supply status includes sufficient power supply, critical power supply, and undervoltage power supply; the heat pump operation minimum power guarantee includes compressor minimum power guarantee, indoor unit air supply minimum power guarantee, outdoor unit heat exchange minimum power guarantee, and valve maintenance minimum power guarantee; the energy storage charging channel status includes charging permitted status, charging current limiting status, and charging prohibited status; the energy storage discharging operation status includes discharging supported status, discharging derating status, and discharging cutoff status; the air conditioning power supply scheduling commands include photovoltaic direct supply commands, energy storage compensation commands, mains power supplement commands, and load power reduction commands.

3. The photovoltaic direct-drive off-grid inverter heat pump air conditioner according to claim 1, characterized in that: The determination of the DC bus voltage drop amplitude within the DC bus voltage protection range and the battery charge state range within the energy storage charge percentage range, and the generation of energy storage discharge operation status, includes dividing the current DC bus voltage value into three DC bus voltage protection ranges: below the undervoltage threshold, equal to the undervoltage threshold, and above the undervoltage threshold, based on the undervoltage threshold as a comparison benchmark.

4. The photovoltaic direct-drive off-grid inverter heat pump air conditioner according to claim 1, characterized in that: The energy storage battery pack's charge percentage is divided into a zero range, a range greater than zero and less than 20%, a range of 20% to 80%, and a range greater than 80%.

5. The photovoltaic direct-drive off-grid inverter heat pump air conditioner according to claim 1, characterized in that, The energy harvesting module includes: The electrical parameter acquisition submodule acquires the output voltage, output current and current DC bus voltage of the photovoltaic module in the photovoltaic direct-drive off-grid variable frequency heat pump air conditioner, monitors the writing status of the voltage channel, current channel and DC bus channel in the sampling buffer, verifies the channel data ownership relationship according to the sampling time sequence, writes the verification mark to the end of the data, and generates an electrical sampling vector. The power evaluation submodule calls the power sampling vector, reads the output voltage value according to the voltage channel, reads the output current value according to the current channel, reads data within the same sampling time sequence, calculates the photovoltaic input power value, writes the power data into the corresponding register bit, and binds the verification flag to the power register bit to obtain the photovoltaic input power; The power generation submodule reads the current DC bus voltage value based on the power sampling vector, calls the photovoltaic input power, detects the bus voltage access threshold and input power access threshold in the control register, determines the access status corresponding to the current DC bus voltage value and photovoltaic input power value, writes the determination flag into the power supply status bit, and generates the DC power supply status.

6. The photovoltaic direct-drive off-grid inverter heat pump air conditioner according to claim 1, characterized in that, The loop module includes: Based on the DC power supply status, the status access submodule collects the frequency value of the DC inverter compressor, the speed value of the indoor circulating fan, the speed value of the outdoor circulating fan, and the holding current value of the four-way reversing valve. It monitors the channel writing status in the operation sampling buffer area, determines the relationship between the operation data and the DC power supply status according to the sampling timing, and generates an operation condition vector. The power mapping submodule calls the operating condition vector, reads the operating permit identifier according to the DC power supply status, detects the power mapping table in the drive register area, and calculates the component power value for the DC inverter compressor frequency value, indoor circulating fan speed value, outdoor circulating fan speed value, and four-way reversing valve holding current value to obtain the component power sequence. The minimum power guarantee submodule, based on the component power sequence, calls the sampling timing identifier in the operating condition vector, reads the operating permit identifier according to the DC power supply status, monitors the write status of the minimum power guarantee register area, calculates the corresponding power sum for the component power sequence values ​​within the same sampling timing, and obtains the minimum power guarantee for heat pump operation.

7. The photovoltaic direct-drive off-grid inverter heat pump air conditioner according to claim 1, characterized in that, The optional charging module includes: The residual power calculation submodule calls the heat pump's guaranteed operating power and the DC power supply status, calls the photovoltaic input power value, reads the power supply permit identifier according to the DC power supply status, calculates the residual power difference for the guaranteed operating power for the photovoltaic input power value and the heat pump's guaranteed operating power under the same sampling time sequence, writes the residual power identifier into the residual power register, and obtains the residual power difference for the guaranteed operating power. The threshold comparison submodule collects the current DC bus voltage value based on the operating backup power difference, detects the compressor driver undervoltage protection threshold, reads the power supply permission identifier according to the DC power supply status, compares the current DC bus voltage value with the compressor driver undervoltage protection threshold for the access relationship, writes the access identifier into the voltage determination register, and generates the bus voltage access value. The channel determination submodule calls the bus voltage access value and the operating backup power difference, reads the power supply permit identifier according to the DC power supply status, monitors the channel writing status of the charging control register area, determines the channel access relationship corresponding to the operating backup power difference, bus voltage access value and power supply permit identifier, writes the channel identifier into the energy storage charging control bit, and generates the energy storage charging channel status.

8. The photovoltaic direct-drive off-grid inverter heat pump air conditioner according to claim 1, characterized in that, The discharge module includes: The discharge acquisition submodule acquires the percentage of charge of the energy storage battery pack, the voltage value of the energy storage terminal, the allowable discharge current value of the energy storage and the current voltage value of the DC bus based on the guaranteed power of the heat pump and the status of the energy storage charging channel. It also monitors the writing status of the discharge sampling buffer channel, determines the relationship between the sampling timing and the operating status, and generates the energy storage operation vector. The voltage drop calculation submodule calls the energy storage operation vector, reads the DC bus voltage value of the previous control cycle in the operation record area of ​​the photovoltaic direct-drive off-grid variable frequency heat pump air conditioner, extracts the current DC bus voltage value according to the sampling time sequence, calculates the bus voltage drop amplitude value for the bus voltage data in the same control cycle link, and obtains the bus voltage drop amplitude. The status determination submodule, based on the bus voltage drop amplitude, calls the energy storage battery pack charge percentage in the energy storage operation vector, detects the DC bus voltage protection range and battery charge state interval, reads the channel status identifier according to the energy storage charging channel status, determines the discharge access relationship, and generates the energy storage discharge operation status.

9. The photovoltaic direct-drive off-grid inverter heat pump air conditioner according to claim 1, characterized in that, The power replenishment module includes: The mains power detection submodule detects the effective voltage value of the AC mains power input terminal for the energy storage discharge operation status and the heat pump operation backup power, monitors the writing status of the supplementary power sampling buffer channel, and generates the mains power access status based on the sampling timing sequence associated with the energy storage discharge operation status, the heat pump operation backup power and the effective voltage value of the AC mains power input terminal. The gap calculation submodule calls the mains access status, reads the discharge permit identifier according to the energy storage discharge operation status, calculates the power supply gap power value and the maximum battery discharge power value based on the heat pump operation minimum power and the effective voltage value of the AC mains input terminal, writes the two power data into the power replenishment register area, and obtains the power replenishment comparison value. Based on the supplementary power comparison value, the scheduling generation submodule calls the mains power access status, reads the discharge permission identifier according to the energy storage discharge operation status, compares the scheduling access relationship between the battery maximum discharge power value and the power supply gap power value, writes the mains power access status value and the scheduling access relationship into the power supply scheduling register, and obtains the air conditioning power supply scheduling instruction.

10. The photovoltaic direct-drive off-grid inverter heat pump air conditioner according to claim 1, characterized in that: When the current voltage of the DC bus is lower than the undervoltage threshold, and the charge percentage of the energy storage battery pack is in the range of 20% to 80% or greater than 80%, the allowable discharge current value of the energy storage and the voltage value of the energy storage terminal are used as inputs to generate the energy storage discharge operation state.

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