Power supply control device and method of photovoltaic air conditioning system and photovoltaic air conditioning system

Abstract

The invention discloses a power supply control device of a photovoltaic air-conditioning system, the photovoltaic air-conditioning system and a power supply control method of the photovoltaic air-conditioning system, and the device is characterized in that a storage battery is connected to the input side of a power supply bus of the photovoltaic air-conditioning system after passing through a third switch; the acquisition module is used for acquiring the photovoltaic voltage of the photovoltaic module, the output voltage of the energy storage system, the residual electric quantity of the energy storage system and the bus voltage of the power supply bus; the control module is used for controlling the on and off of the first switch, the second switch and the third switch by combining the photovoltaic voltage of the photovoltaic module, the output voltage of the energy storage system, the residual electric quantity of the energy storage system and the bus voltage of the power supply bus; and controlling at least one of whether the photovoltaic air conditioning system works or not, whether the photovoltaic module supplies power or not, whether the mains supply supplies power or not, and charging or discharging operation of the energy storage system. According to the scheme, a voltage conversion unit between the energy storage system and the photovoltaic air conditioning system is omitted, the voltage conversion link is reduced, and the energy utilization efficiency is improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of photovoltaic air-conditioning systems, and specifically relates to a power supply control device for a photovoltaic air-conditioning system, a photovoltaic air-conditioning system and a power supply control method thereof, and in particular to an integrated power supply control system integrating household photovoltaics, variable frequency air-conditioning and energy storage systems, a photovoltaic air-conditioning system having the integrated power supply control system, and an integrated power supply control method for the photovoltaic air-conditioning system. Background Art

[0002] Under the background of carbon neutrality, clean and environmentally friendly photovoltaic power generation and its application have become one of the more popular research fields in the world, and the market prospects of photovoltaic related fields are relatively broad; air conditioning systems are large power consumers in households, and how to reduce air conditioning power consumption is the most important research content for household energy conservation and emission reduction. The direct application of photovoltaic energy to air conditioning systems can reduce the dependence of household air conditioning systems on municipal electricity. More and more people are conducting research and launching related products in related schemes. However, photovoltaic energy, as a special energy source, is directly related to weather and time. It can only be used during the day and cannot be used at night, which seriously restricts the promotion and application of photovoltaic energy; therefore, the photovoltaic energy during the day is stored in the energy storage system through energy storage and used at night, which effectively solves the timeliness problem of photovoltaics. However, there is also the problem of power conversion loss in the conversion of photovoltaic energy through charging and discharging of the energy storage system, which affects the utilization rate of photovoltaic energy.

[0003] The above contents are only used to assist in understanding the technical solution of the present invention and do not constitute an admission that the above contents are prior art. Summary of the invention

[0004] The purpose of the present invention is to provide a power supply control device for a photovoltaic air-conditioning system, a photovoltaic air-conditioning system and a power supply control method thereof, so as to solve the problem that in the photovoltaic air-conditioning system, there is a power conversion loss in the conversion of photovoltaic energy through the charging and discharging of an energy storage system, which affects the utilization rate of the photovoltaic energy, so as to achieve the effect of improving the energy utilization efficiency by eliminating the voltage conversion unit between the energy storage system and the air-conditioning system, reducing the voltage conversion links between the energy storage system and the air-conditioning system.

[0005] The present invention provides a power supply control device for a photovoltaic air-conditioning system, wherein the power supply of the photovoltaic air-conditioning system comprises: a photovoltaic component, an energy storage system and a mains supply, wherein the energy storage system has a battery; a photovoltaic MPPT unit, a rectifier unit, a PFC unit and an external machine load unit are arranged on the external machine side of the photovoltaic air-conditioning system; an internal machine load unit is arranged on the internal machine side of the photovoltaic air-conditioning system; after the photovoltaic component is connected to the photovoltaic MPPT unit through a first switch, the mains supply is connected to the mains supply through a second switch, the rectifier unit and the PFC circuit, and the battery is connected to the mains supply through a third switch, the output side of the power supply bus is connected to the external machine load unit and the internal machine load unit respectively; the power supply of the photovoltaic air-conditioning system The control device comprises: an acquisition module and a control module; wherein the acquisition module is used to acquire the photovoltaic voltage of the photovoltaic component, acquire the output voltage of the energy storage system, acquire the remaining power of the energy storage system, and acquire the bus voltage of the power supply bus; the control module is used to control the opening and closing of the first switch, the second switch and the third switch in combination with the photovoltaic voltage of the photovoltaic component, the output voltage of the energy storage system, the remaining power of the energy storage system, and the bus voltage of the power supply bus, and in combination with controlling the opening and closing of the photovoltaic MPPT unit and the PFC unit, so as to control at least one of the following: whether the photovoltaic air-conditioning system works, whether the photovoltaic component is powered, whether the mains is powered, and the charging or discharging operation of the energy storage system.

[0006] In some embodiments, the voltage selection of the energy storage system is determined based on the required voltage of the power supply bus of the photovoltaic air-conditioning system; wherein, the rated voltage of the energy storage system needs to be equal to the rated operating voltage of the photovoltaic air-conditioning system; the maximum voltage allowed by the energy storage system needs to be less than the maximum operating voltage allowed by the internal controller hardware and load unit of the photovoltaic air-conditioning system, and the external controller hardware and load unit of the photovoltaic air-conditioning system.

[0007] In some embodiments, the control module controls the opening and closing of the first switch, the second switch and the third switch in combination with the photovoltaic voltage of the photovoltaic component, the output voltage of the energy storage system, the remaining power of the energy storage system, and the bus voltage of the power supply bus, and controls the opening and closing of the photovoltaic MPPT unit and the PFC unit in combination to control at least one of the following: whether the photovoltaic air-conditioning system works, whether the photovoltaic component is powered, whether the mains is powered, and the charging or discharging operation of the energy storage system, including: when the first switch is closed, if the photovoltaic voltage of the photovoltaic component is greater than the maximum voltage allowed by the photovoltaic air-conditioning system, then the first switch is controlled to be disconnected; wherein the maximum voltage allowed by the photovoltaic air-conditioning system is the maximum operating voltage allowed by the indoor load unit and the outdoor load unit; when the second switch is closed, if the input voltage of the mains is greater than the maximum voltage allowed by the photovoltaic air-conditioning system, then the second switch is controlled to be disconnected; when the third switch is closed, if the bus voltage of the power supply bus is greater than the maximum voltage allowed by the energy storage system, then the third switch is controlled to be disconnected.

[0008] In some embodiments, the control module controls the opening and closing of the first switch, the second switch and the third switch in combination with the photovoltaic voltage of the photovoltaic component, the output voltage of the energy storage system, the remaining power of the energy storage system, and the bus voltage of the power supply bus, and controls the opening and closing of the photovoltaic MPPT unit and the PFC unit in combination to control at least one of the following: whether the photovoltaic air-conditioning system is working, whether the photovoltaic component is powered, whether the mains is powered, and the charging or discharging operation of the energy storage system, and also includes: after the photovoltaic component is powered on, controlling the first switch to close, setting the target voltage to the output voltage of the energy storage system, starting the photovoltaic MPPT unit or the PFC unit, and determining whether the absolute value of the difference between the output voltage of the energy storage system and the bus voltage of the power supply bus is less than a preset voltage Error; if it is determined that the absolute value of the difference between the output voltage of the energy storage system and the bus voltage of the power supply bus is less than a preset voltage error, the third switch is controlled to close to start the charging mode of the energy storage system and charge the battery in the energy storage system; at this time, the working mode of charging only the energy storage system is executed; if it is determined that the remaining power of the energy storage system is less than or equal to the preset charging power threshold, the preset constant current control strategy is used to control the charging operation of the energy storage system; if it is determined that the remaining power of the energy storage system is greater than the preset charging power threshold, the preset constant voltage control strategy is used to control the charging operation of the energy storage system; if it is determined that the remaining power of the energy storage system is equal to the preset full power threshold, the third switch is controlled to be disconnected, the started photovoltaic MPPT unit or the PFC unit is controlled to stop working, and the charging of the battery is completed.

[0009] In some embodiments, the control module controls the opening and closing of the first switch, the second switch and the third switch in combination with the photovoltaic voltage of the photovoltaic component, the output voltage of the energy storage system, the remaining power of the energy storage system, and the bus voltage of the power supply bus, and controls the opening and closing of the photovoltaic MPPT unit and the PFC unit in combination to control at least one of the following: whether the photovoltaic air-conditioning system works or not, whether the photovoltaic component is powered on or not, whether the mains is powered on or not, and the charging or discharging operation of the energy storage system, and also includes: after the photovoltaic component is powered on, controlling the first switch to close; after the mains is powered on, controlling the second switch to close; setting the target voltage of the photovoltaic MPPT unit and the target voltage of the PFC unit, starting the photovoltaic MPPT unit and the PFC unit, and controlling the third switch to open so that the photovoltaic air-conditioning system works and the energy storage system does not work; at this time, a working mode in which only the photovoltaic air-conditioning system works is executed; wherein, in order to achieve the purpose of giving priority to the voltage of the photovoltaic component, the working target voltage of the photovoltaic MPPT unit is further made greater than the target voltage of the PFC unit.

[0010] In some embodiments, the control module controls the opening and closing of the first switch, the second switch and the third switch in combination with the photovoltaic voltage of the photovoltaic component, the output voltage of the energy storage system, the remaining power of the energy storage system, and the bus voltage of the power supply bus, and controls the opening and closing of the photovoltaic MPPT unit and the PFC unit in combination to control at least one of the following: whether the photovoltaic air-conditioning system works or not, whether the photovoltaic component is powered or not, whether the mains is powered or not, and the charging or discharging operation of the energy storage system, and also includes: after the photovoltaic component is powered on, controlling the first switch to close, setting the target voltage to the output voltage of the energy storage system, starting the photovoltaic MPPT unit, and determining whether the absolute value of the difference between the output voltage of the energy storage system and the bus voltage of the power supply bus is is less than a preset voltage error; if it is determined that the absolute value of the difference between the output voltage of the energy storage system and the bus voltage of the power supply bus is less than a preset voltage error, the third switch is controlled to close to start the charging mode of the energy storage system and charge the battery in the energy storage system; at this time, the photovoltaic component and the energy storage system simultaneously power the photovoltaic air-conditioning system, and execute the working mode in which the photovoltaic air-conditioning system works and the energy storage system is charged; according to the power of the photovoltaic component and the power of the photovoltaic air-conditioning system, the maximum allowable charging current of the energy storage system is determined, and the charging operation of the energy storage system is controlled according to the maximum allowable charging current of the energy storage system, until the charging of the battery is completed, and then the third switch is controlled to be disconnected, switching to the working mode in which only the photovoltaic air-conditioning system works.

[0011] In some embodiments, the control module controls the opening and closing of the first switch, the second switch, and the third switch in combination with the photovoltaic voltage of the photovoltaic component, the output voltage of the energy storage system, the remaining power of the energy storage system, and the bus voltage of the power supply bus, and controls the opening and closing of the photovoltaic MPPT unit and the PFC unit in combination to control at least one of the following: whether the photovoltaic air-conditioning system works or not, whether the photovoltaic component is powered or not, whether the mains is powered or not, and the charging or discharging operation of the energy storage system, and also includes: after the photovoltaic component is powered on, controlling the first switch to close, setting the target voltage to the output voltage of the energy storage system, starting the photovoltaic MPPT unit, and determining whether the absolute value of the difference between the output voltage of the energy storage system and the bus voltage of the power supply bus is less than a preset voltage error; if it is determined that the output voltage of the energy storage system is If the absolute value of the difference between the voltage of the photovoltaic module and the bus voltage of the power supply bus is less than the preset voltage error, the third switch is controlled to close to start the discharge mode of the energy storage system and discharge the battery in the energy storage system; at this time, the photovoltaic module and the energy storage system simultaneously power the photovoltaic air-conditioning system or the energy storage system alone powers the photovoltaic air-conditioning system, and the working mode in which the photovoltaic air-conditioning system works and the energy storage system discharges is executed; according to the power of the photovoltaic module and the power of the photovoltaic air-conditioning system, the maximum allowable output current of the photovoltaic module is determined, and the discharge operation of the energy storage system is controlled according to the maximum allowable output current of the photovoltaic module, until the discharge current of the energy storage system is less than 0 and the power of the photovoltaic module is greater than the power of the photovoltaic air-conditioning system, the working mode in which the photovoltaic air-conditioning system works and the energy storage system is charged is switched.

[0012] Matching the above-mentioned device, the present invention provides a photovoltaic air-conditioning system on another aspect, including: the power supply control device of the photovoltaic air-conditioning system mentioned above.

[0013] Matching the above-mentioned photovoltaic air-conditioning system, the present invention provides a power supply control method for a photovoltaic air-conditioning system on another aspect, comprising: obtaining the photovoltaic voltage of the photovoltaic component, obtaining the output voltage of the energy storage system, obtaining the remaining power of the energy storage system, and obtaining the bus voltage of the power supply bus; combining the photovoltaic voltage of the photovoltaic component, the output voltage of the energy storage system, the remaining power of the energy storage system, and the bus voltage of the power supply bus, controlling the opening and closing of the first switch, the second switch, and the third switch, and combining the control of the opening and closing of the photovoltaic MPPT unit and the PFC unit to control at least one of the following: whether the photovoltaic air-conditioning system is working, whether the photovoltaic component is powered, whether the mains is powered, and the charging or discharging operation of the energy storage system.

[0014] In some embodiments, the voltage selection of the energy storage system is determined based on the required voltage of the power supply bus of the photovoltaic air-conditioning system; wherein, the rated voltage of the energy storage system needs to be equal to the rated operating voltage of the photovoltaic air-conditioning system; the maximum voltage allowed by the energy storage system needs to be less than the maximum operating voltage allowed by the internal controller hardware and load unit of the photovoltaic air-conditioning system, and the external controller hardware and load unit of the photovoltaic air-conditioning system.

[0015] In some embodiments, the opening and closing of the first switch, the second switch and the third switch are controlled in combination with the photovoltaic voltage of the photovoltaic component, the output voltage of the energy storage system, the remaining power of the energy storage system, and the bus voltage of the power supply bus, and the opening and closing of the photovoltaic MPPT unit and the PFC unit are controlled in combination to control at least one of the following: whether the photovoltaic air-conditioning system works, whether the photovoltaic component is powered, whether the mains is powered, and the charging or discharging operation of the energy storage system, including: when the first switch is closed, if the photovoltaic voltage of the photovoltaic component is greater than the maximum voltage allowed by the photovoltaic air-conditioning system, the first switch is controlled to be disconnected; wherein the maximum voltage allowed by the photovoltaic air-conditioning system is the maximum operating voltage allowed by the indoor load unit and the outdoor load unit; when the second switch is closed, if the input voltage of the mains is greater than the maximum voltage allowed by the photovoltaic air-conditioning system, the second switch is controlled to be disconnected; when the third switch is closed, if the bus voltage of the power supply bus is greater than the maximum voltage allowed by the energy storage system, the third switch is controlled to be disconnected.

[0016] In some embodiments, the first switch, the second switch and the third switch are controlled to be turned on and off in combination with the photovoltaic voltage of the photovoltaic component, the output voltage of the energy storage system, the remaining power of the energy storage system, and the bus voltage of the power supply bus, and the photovoltaic MPPT unit and the PFC unit are controlled to be turned on and off in combination to control at least one of the following: whether the photovoltaic air-conditioning system works, whether the photovoltaic component is powered, whether the mains is powered, and the charging or discharging operation of the energy storage system, and also includes: after the photovoltaic component is powered on, the first switch is controlled to be closed, the target voltage is set to the output voltage of the energy storage system, the photovoltaic MPPT unit or the PFC unit is started, and it is determined whether the absolute value of the difference between the output voltage of the energy storage system and the bus voltage of the power supply bus is less than a preset voltage error; If it is determined that the absolute value of the difference between the output voltage of the energy storage system and the bus voltage of the power supply bus is less than a preset voltage error, the third switch is controlled to close to start the charging mode of the energy storage system and charge the battery in the energy storage system; at this time, the working mode of charging only the energy storage system is executed; if it is determined that the remaining power of the energy storage system is less than or equal to the preset charging power threshold, the preset constant current control strategy is used to control the charging operation of the energy storage system; if it is determined that the remaining power of the energy storage system is greater than the preset charging power threshold, the preset constant voltage control strategy is used to control the charging operation of the energy storage system; if it is determined that the remaining power of the energy storage system is equal to the preset full power threshold, the third switch is controlled to be disconnected, and the started photovoltaic MPPT unit or the PFC unit is controlled to stop working, so as to complete the charging of the battery.

[0017] In some embodiments, the opening and closing of the first switch, the second switch and the third switch are controlled in combination with the photovoltaic voltage of the photovoltaic component, the output voltage of the energy storage system, the remaining power of the energy storage system, and the bus voltage of the power supply bus, and the opening and closing of the photovoltaic MPPT unit and the PFC unit are controlled in combination to control at least one of the following: whether the photovoltaic air-conditioning system works or not, whether the photovoltaic component is powered or not, whether the mains is powered or not, and the charging or discharging operation of the energy storage system, and also includes: after the photovoltaic component is powered on, the first switch is controlled to be closed; after the mains is powered on, the second switch is controlled to be closed; the target voltage is set to the output voltage of the energy storage system, the photovoltaic MPPT unit and the PFC unit are started, and the third switch is controlled to be disconnected so that the photovoltaic air-conditioning system works and the energy storage system does not work; at this time, a working mode in which only the photovoltaic air-conditioning system works is executed; wherein, based on the set target voltage, the working target voltage of the photovoltaic MPPT unit is further made greater than the target voltage of the PFC unit.

[0018] In some embodiments, the first switch, the second switch, and the third switch are controlled to be turned on and off in combination with the photovoltaic voltage of the photovoltaic component, the output voltage of the energy storage system, the remaining power of the energy storage system, and the bus voltage of the power supply bus, and the photovoltaic MPPT unit and the PFC unit are controlled to be turned on and off in combination to control at least one of the following: whether the photovoltaic air-conditioning system is working, whether the photovoltaic component is powered, whether the mains is powered, and the charging or discharging operation of the energy storage system, and also includes: after the photovoltaic component is powered on, the first switch is controlled to be closed, the target voltage is set to the output voltage of the energy storage system, the photovoltaic MPPT unit is started, and it is determined whether the absolute value of the difference between the output voltage of the energy storage system and the bus voltage of the power supply bus is less than Preset voltage error; if it is determined that the absolute value of the difference between the output voltage of the energy storage system and the bus voltage of the power supply bus is less than the preset voltage error, the third switch is controlled to close to start the charging mode of the energy storage system and charge the battery in the energy storage system; at this time, the photovoltaic component and the energy storage system simultaneously power the photovoltaic air-conditioning system, and execute the working mode in which the photovoltaic air-conditioning system works and the energy storage system is charged; according to the power of the photovoltaic component and the power of the photovoltaic air-conditioning system, the maximum allowable charging current of the energy storage system is determined, and the charging operation of the energy storage system is controlled according to the maximum allowable charging current of the energy storage system, until the charging of the battery is completed, and then the third switch is controlled to be disconnected, switching to the working mode in which only the photovoltaic air-conditioning system works.

[0019] In some embodiments, the opening and closing of the first switch, the second switch and the third switch are controlled in combination with the photovoltaic voltage of the photovoltaic component, the output voltage of the energy storage system, the remaining power of the energy storage system, and the bus voltage of the power supply bus, and the opening and closing of the photovoltaic MPPT unit and the PFC unit are controlled in combination to control at least one of the following: whether the photovoltaic air-conditioning system is working, whether the photovoltaic component is powered, whether the mains is powered, and the charging or discharging operation of the energy storage system, and also includes: after the photovoltaic component is powered on, controlling the first switch to close, setting the target voltage to the output voltage of the energy storage system, starting the photovoltaic MPPT unit, and determining whether the absolute value of the difference between the output voltage of the energy storage system and the bus voltage of the power supply bus is less than a preset voltage error; if it is determined that the output voltage of the energy storage system is less than the preset voltage error, the target voltage is set to the output voltage of the energy storage system, and ... If the absolute value of the difference between the bus voltages of the power supply buses is less than a preset voltage error, the third switch is controlled to close to start the discharge mode of the energy storage system and discharge the battery in the energy storage system; at this time, the photovoltaic module and the energy storage system simultaneously power the photovoltaic air-conditioning system or the energy storage system alone powers the photovoltaic air-conditioning system, and a working mode in which the photovoltaic air-conditioning system works and the energy storage system discharges is executed; according to the power of the photovoltaic module and the power of the photovoltaic air-conditioning system, the maximum allowable output current of the photovoltaic module is determined, and the discharge operation of the energy storage system is controlled according to the maximum allowable output current of the photovoltaic module, until the discharge current of the energy storage system is less than 0 and the power of the photovoltaic module is greater than the power of the photovoltaic air-conditioning system, the working mode in which the photovoltaic air-conditioning system works and the energy storage system is charged is switched.

[0020] Therefore, the scheme of the present invention, for the case where the external input source of the photovoltaic air-conditioning system is the photovoltaic module, the energy storage system and the mains, is provided in the outdoor unit and the control unit with a first switch and a photovoltaic MPPT circuit connected between the photovoltaic module and the power supply bus, a second switch connected between the mains and the photovoltaic module, a rectifier bridge and a PFC circuit, a switching power supply connected to the power supply bus, other loads inside the air conditioner, a compressor connected to the power supply bus via a first inverter, an outdoor fan connected to the power supply bus via a second inverter, an indoor fan connected to the power supply bus via a third inverter is provided in the indoor unit and the control unit, and a battery connected to the power supply bus via a third switch is provided in the energy storage and control unit; when working, the outdoor unit controller determines the charging and discharging operation of the battery according to the photovoltaic intensity of the photovoltaic module, the state of the battery and the operating state of the air-conditioning system; thereby, by eliminating the voltage conversion unit (such as a bidirectional DC-DC inverter) between the energy storage system and the air-conditioning system, the voltage conversion link between the energy storage system and the air-conditioning system is reduced, and the energy utilization efficiency is improved.

[0021] Other features and advantages of the present invention will be set forth in the description which follows, and in part will be apparent from the description, or may be learned by practice of the present invention.

[0022] The technical solution of the present invention is further described in detail below through the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 It is a structural schematic diagram of an embodiment of a power supply control device for a photovoltaic air conditioning system of the present invention;

[0024] Figure 2 It is a structural schematic diagram of an embodiment of a household light storage system in a related scheme;

[0025] Figure 3 It is a structural schematic diagram of an embodiment of a household light storage system of the present invention;

[0026] Figure 4 It is a structural schematic diagram of an embodiment of a household light storage system of the present invention;

[0027] Figure 5 It is a flow chart of the pure charging mode of the energy storage system;

[0028] Figure 6 Schematic diagram of the working process of photovoltaic air conditioning system;

[0029] Figure 7 A schematic diagram of the charging mode of the energy storage system + the working process of the air conditioning system;

[0030] Figure 8 Schematic diagram of the discharge mode of the energy storage system + the working process of the air conditioning system;

[0031] Fig. 9 It is a schematic diagram of the conversion efficiency of charging and discharging of the energy storage system;

[0032] Fig.10 A schematic flow chart of an embodiment of a power supply control method for a photovoltaic air conditioning system of the present invention;

[0033] Fig.11 A flow chart of an embodiment of control in the method of the present invention when only the energy storage system is charged;

[0034] Fig.12 It is a flow chart of an embodiment of the control in the method of the present invention when only the photovoltaic air conditioning system is working;

[0035] Fig.13 A flow chart of an embodiment of the control in the method of the present invention when the photovoltaic air-conditioning system is working and the energy storage system is charging;

[0036] Fig.14 It is a flow chart of an embodiment of the control in the method of the present invention when the photovoltaic air-conditioning system is working and the energy storage system is discharging. DETAILED DESCRIPTION

[0037] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention will be clearly and completely described below in conjunction with the specific embodiments of the present invention and the corresponding drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0038] Considering that the conversion of photovoltaic energy through charging and discharging of the energy storage system has the problem of power conversion loss, it affects the utilization rate of photovoltaic energy. The more power conversion links there are, the more energy loss there is. Therefore, how to reduce the power conversion links and improve energy utilization efficiency is an important research topic.

[0039] Therefore, the scheme of the present invention proposes a new control strategy from the perspective of an integrated power supply control system integrating household photovoltaic, variable frequency air conditioning and energy storage system: in view of the complex power supply system of household photovoltaic storage system (i.e., a system integrating household photovoltaic, variable frequency air conditioning and energy storage system), and the need to design a dedicated control unit for the energy storage system, the scheme of the present invention cancels the bidirectional DC-DC inverter controlled by the energy storage system, and the charging and discharging of the energy storage system are controlled by the photovoltaic MPPT circuit of the built-in control unit of the air-conditioning system (i.e., photovoltaic air-conditioning) and the power factor correction (Power Factor Correction, PFC) circuit of the mains, and the energy storage system exchanges data with the built-in control unit of the air-conditioning system through communication. By optimizing the power control strategy and systematic integrated design, the bidirectional DC-DC (i.e., a device that converts electric energy of one voltage value into electric energy of another voltage value in a DC circuit) inverter controlled by the energy storage system is cancelled, the power conversion links are reduced, and the energy utilization efficiency is improved.

[0040] According to an embodiment of the present invention, a power supply control device for a photovoltaic air conditioning system is provided. Figure 1The schematic diagram of the structure of an embodiment of the device of the present invention is shown. The power supply of the photovoltaic air-conditioning system includes: photovoltaic components, energy storage system and mains electricity, and the energy storage system has a battery; on the external machine side of the photovoltaic air-conditioning system, a photovoltaic MPPT unit, a rectifier unit, a PFC unit and an external machine load unit are arranged, the photovoltaic MPPT unit is such as a photovoltaic MPPT circuit, the rectifier unit is such as a rectifier bridge DB1, the PFC unit is such as a PFC circuit, the external machine load unit is such as a switching power supply, other loads inside the air conditioner, a compressor and inverter 1, an external fan and inverter 2; on the internal machine side of the photovoltaic air-conditioning system, an internal machine load unit is arranged, such as an internal fan and inverter 3; the photovoltaic components After passing through the first switch and the photovoltaic MPPT unit, the mains power passes through the second switch, the rectifier unit and the PFC circuit, and the battery passes through the third switch, and is connected to the input side of the power supply bus of the photovoltaic air-conditioning system. That is, after the photovoltaic voltage is inverted, the mains power passes through the PFC circuit, and the energy storage system passes through the third switch, they are all connected to the voltage bus; the first switch is like the first switch circuit K1, the second switch is like the second switch circuit K2, and the third switch is like the third switch circuit K3; the output side of the power supply bus is connected to the external machine load unit and the internal machine load unit respectively; Figure 2 FIG. 1 is a schematic diagram of a structure of an embodiment of a household light storage system in a related solution. Figure 2 As shown in the figure, the energy storage unit (such as a battery) in the energy storage system is connected to the PFC circuit of the mains, the photovoltaic MPPT circuit of the photovoltaic module, and the load inverter of the air conditioning system through a bidirectional DC-DC inverter; the load of the air conditioning system is such as a compressor, an outdoor fan, an indoor fan, etc., and the load inverter of the air conditioning system is such as a compressor inverter, an outdoor fan inverter, an indoor fan inverter, etc. The alternating current (AC) of the mains is output as direct current (DC) after rectification and filtering modules, and then connected to the bidirectional DC-DC inverter and the load inverter after passing through the PFC circuit. The photovoltaic voltage output by the photovoltaic module is connected to the bidirectional DC-DC inverter and the load inverter after passing through the filtering module and the photovoltaic MPPT circuit. Figure 3 FIG. 1 is a schematic diagram of the structure of an embodiment of the household light storage system of the present invention. Figure 3 Compared with the household solar storage system shown in Figure 2 The household solar energy storage system shown in the figure eliminates the bidirectional DC-DC inverter, which can save installation space, save costs and improve efficiency.

[0041] Figure 4 FIG. 1 is a schematic diagram of the structure of an embodiment of the household light storage system of the present invention. Figure 4As shown, the entire household solar energy storage system consists of an indoor unit and control unit, an energy storage and control unit, and an outdoor unit and control unit. The outdoor unit and control unit include: a photovoltaic MPPT circuit on the output side of the photovoltaic module, a rectifier bridge DB1 and a PFC circuit on the output side of the mains power supply, a switch circuit K1 is provided between the output side of the solar photovoltaic module and the photovoltaic MPPT circuit, a switch circuit K2 is provided between the output side of the mains power supply AC and the rectifier bridge DB1, a switching power supply, other loads inside the air conditioner, a compressor and an inverter 1 connected to the compressor, an outdoor fan and an inverter 2 connected to the outdoor fan; the photovoltaic MPPT circuit includes an inductor L1, a diode D1 and a switch tube Q1, and the PFC circuit includes an inductor L2, a diode D2 and a switch tube Q2. The energy storage and control unit includes: a battery, and a switch circuit K3 connected to the output end of the battery. The indoor unit and control unit include: an indoor fan and an inverter 3 connected to the indoor fan. One end of the solar photovoltaic module is connected to the anode of the diode D1 through the switch circuit K1 and the inductor L1, and the cathode of the diode D1 is connected to the first connection end of the power supply bus of the photovoltaic air conditioning system; the collector of the switch tube Q1 is connected to the anode of the diode D1, the emitter of the switch tube Q1 is grounded, and is connected to the other end of the solar photovoltaic module and the second connection end of the power supply bus of the photovoltaic air conditioning system. One end of the mains AC is connected to one end of the input end of the rectifier bridge DB1 through the switch circuit K2, the other end of the mains AC is connected to the other end of the input end of the rectifier bridge DB1, one end of the output end of the rectifier bridge DB1 is connected to the anode of the diode D2 through the inductor L2, and the cathode of the diode D2 is connected to the first connection end of the power supply bus of the photovoltaic air conditioning system; the collector of the switch tube Q2 is connected to the anode of the diode D2, the emitter of the switch tube Q2 is grounded, and is connected to the other end of the output end of the rectifier bridge DB1 and the second connection end of the power supply bus of the photovoltaic air conditioning system.

[0042] exist Figure 4 In the example shown, the photovoltaic voltage VDC1 output by the photovoltaic power source (i.e., the solar photovoltaic module) is converted into a DC voltage after passing through the photovoltaic MPPT circuit, and is connected to the DC voltage of the voltage VDC2 provided by the mains after passing through the PFC circuit to form a system bus voltage VDC4, which is directly supplied to inverter 1 and inverter 2 after capacitor filtering to drive the compressor and the outdoor fan, and also supplies power to the switching power supply; the power supply for the indoor unit and the control unit is also directly provided by the bus voltage of the outdoor unit and the control unit; the output of the energy storage and control unit (i.e., the output voltage VDC3 of the battery) is directly connected to the system bus voltage.

[0043] In the scheme of the present invention, the bidirectional DC-DC inverter controlled by the energy storage system is cancelled, and the voltage of the energy storage system is set to about 370 volts from the perspective of the household photovoltaic storage system. Specifically, a suitable voltage is set according to the different requirements of the air-conditioning system bus voltage, so that the energy storage system directly supplies power to the air-conditioning system. There is no need for the bidirectional DC-DC inverter controlled by the energy storage system to perform secondary conversion of the photovoltaic voltage, thereby reducing the power conversion links and improving energy utilization efficiency.

[0044] In the scheme of the present invention, Figure 1 As shown, the power supply control device of the photovoltaic air conditioning system includes: an acquisition module and a control module, the acquisition module is such as a voltage detection device, and the control module is such as an external unit controller.

[0045] The acquisition module is used to acquire the photovoltaic voltage of the photovoltaic module, acquire the output voltage of the energy storage system, acquire the remaining power of the energy storage system, and acquire the bus voltage of the power supply bus. The photovoltaic voltage of the photovoltaic module is such as voltage VDC1, the output voltage of the energy storage system is such as voltage VDC3, the remaining power of the energy storage system is such as the state of charge SOC of the battery, and the bus voltage of the power supply bus is such as DC bus voltage VDC4.

[0046] The control module is used to control the opening and closing of the first switch, the second switch and the third switch in combination with the photovoltaic voltage of the photovoltaic component, the output voltage of the energy storage system, the remaining power of the energy storage system, and the bus voltage of the power supply bus, and to control the opening and closing of the photovoltaic MPPT unit and the PFC unit in combination to control at least one of the following: whether the photovoltaic air-conditioning system is working, whether the photovoltaic component is powered, whether the mains is powered, and the charging or discharging operation of the energy storage system.

[0047] The solution of the present invention eliminates the bidirectional DC-DC inverter controlled by the energy storage system. The charging and discharging of the energy storage system are controlled by the photovoltaic MPPT circuit of the built-in control unit of the air-conditioning system (i.e., photovoltaic air-conditioning system) and the PFC circuit of the mains. The energy storage system exchanges data with the built-in control unit of the air-conditioning system through communication, reducing the voltage conversion link between the energy storage system and the air-conditioning system, thereby reducing the power conversion link and improving energy utilization efficiency. At the same time, due to the elimination of the bidirectional DC-DC inverter controlled by the energy storage system, not only the cost is saved, but also the installation space and installation time of the customer are saved.

[0048] In some embodiments, the voltage selection of the energy storage system is determined according to the required voltage of the power supply bus of the photovoltaic air conditioning system. The rated voltage of the energy storage system needs to be equal to the rated working voltage of the photovoltaic air conditioning system; the maximum voltage allowed by the energy storage system needs to be less than the maximum working voltage allowed by the internal controller hardware and load unit of the photovoltaic air conditioning system, and the external controller hardware and load unit of the photovoltaic air conditioning system.

[0049] exist Figure 4 In the example shown, the design of the energy storage and control unit is the key to the operation of the entire household solar energy storage system. Since the output voltage VDC3 of the battery in the energy storage system is directly connected to the bus voltage VDC4 of the air conditioning system, the bus voltage of the energy storage system needs to meet the operating requirements of the air conditioning system. If the rated operating voltage of the air conditioning system is V an , then the rated voltage value of the energy storage system is V cn It should also be designed in this way, that is, V cn =V an Only in this way can the voltage of the energy storage system and the bus voltage of the air conditioning system be directly connected without the need for a conversion unit. Take the example of selecting lithium iron phosphate batteries for energy storage units (lithium titanate or ternary lithium batteries can also be selected). Since the voltage of the battery is different under different states of charge, the rated voltage of a single cell is 3.2 volts, and the voltage of a single cell when fully charged is about 3.65 volts. If the rated voltage of the energy storage system is 371.2 volts, the maximum operating voltage after full charge is 423.4 volts. Therefore, when designing an energy storage system, it is necessary to consider the maximum voltage V of the energy storage system when the battery is fully charged. bmax It needs to be smaller than the maximum operating voltage V allowed by the indoor unit and control unit, outdoor unit and control unit of the air conditioning system. amax , that is, V bmax ≤V amax .

[0050] In the related schemes, the battery of the energy storage system was designed without considering the needs of the air conditioning system. The energy storage system and the air conditioning system were designed independently, and both needed to be converted twice through DC-DC. In the related schemes, the charging and discharging of the energy storage cabinet must pass through DC-DC. However, in the scheme of the present invention, the energy storage system does not need DC-DC, and the charging and discharging of the energy storage cabinet are controlled by the external mainboard of the air conditioning system. The external mainboard of the air conditioning system not only integrates the photovoltaic MPPT circuit, but also has the charging and discharging control functions. In the scheme of the present invention, the photovoltaic MPPT circuit and the external controller of the air conditioning system are integrated to realize single-core control, and the DC-DC of the energy storage part is eliminated at the same time, and the DC-DC related to the energy storage is integrated and controlled through the external controller of the air conditioning system.

[0051] In some embodiments, the control module, in combination with the photovoltaic voltage of the photovoltaic component, the output voltage of the energy storage system, the remaining power of the energy storage system, and the bus voltage of the power supply bus, controls the opening and closing of the first switch, the second switch, and the third switch, and controls the opening and closing of the photovoltaic MPPT unit and the PFC unit in combination to control at least one of the following: whether the photovoltaic air-conditioning system is working, whether the photovoltaic component is powered, whether the mains is powered, and the charging or discharging operation of the energy storage system, including: a process of controlling based on the maximum voltage allowed by the photovoltaic air-conditioning system, specifically including at least one of the following control situations.

[0052] The first control scenario: the control module is specifically used to control the first switch to be opened if the photovoltaic voltage of the photovoltaic component is greater than the maximum voltage allowed by the photovoltaic air-conditioning system when the first switch is closed; wherein the maximum voltage allowed by the photovoltaic air-conditioning system is the maximum operating voltage allowed by the indoor load unit and the outdoor load unit.

[0053] The second control scenario: the control module is specifically used to control the second switch to be opened if the input voltage of the mains is greater than the maximum voltage allowed by the photovoltaic air-conditioning system when the second switch is closed.

[0054] The third control scenario: the control module is further configured to control the third switch to be opened if the bus voltage of the power supply bus is greater than the maximum voltage allowed by the energy storage system when the third switch is closed.

[0055] exist Figure 4 In the example shown, the switch circuit K1 controls the input of the solar photovoltaic power source; the switch circuit K2 controls the input of the mains power; and the switch circuit K3 controls whether the battery is connected to the air conditioning system. When it is detected that the photovoltaic input voltage VDC1 is greater than the maximum voltage allowed by the entire household photovoltaic energy storage system, the switch circuit K1 is disconnected; when it is detected that the mains power input voltage VDC2 is greater than the maximum voltage allowed by the entire household photovoltaic energy storage system, the switch circuit K2 is disconnected; if it is detected that the system bus voltage VDC4 is greater than the maximum voltage allowed by the energy storage system V bmax When VDC4>V bmax To ensure the safety of the battery, the switch circuit K3 is disconnected.

[0056] In the solution of the present invention, in order to prevent external overvoltage, the external controller detects the input photovoltaic voltage. When the photovoltaic voltage exceeds the allowable voltage, the switch connected to the photovoltaic module is disconnected, and the photovoltaic voltage is not connected to the external power supply system (i.e., the power supply system controlled by the external controller); only when the photovoltaic overvoltage meets the set requirements, the switch connected to the photovoltaic module is closed, and the photovoltaic voltage is connected to the external power supply system, thereby improving safety.

[0057] The solution of the present invention, in the topology of the light-storage-air system, eliminates the DC-DC between the energy storage system and the air conditioner, and the bus of the air conditioner is connected to the bus of the energy storage cabinet through the switch circuit K3; the photovoltaic MPPT circuit between the photovoltaic part and the air conditioning system is eliminated, and the photovoltaic MPPT circuit is integrated into the external controller of the air conditioning system; the charging and discharging control of the energy storage system is realized by controlling the photovoltaic MPPT circuit and the switch circuit K3. Under different working states of the air conditioning system, the integrated control of the light-storage-air system can be realized by controlling the states of the switch circuit K1, the switch circuit K2, the switch circuit K3 and the photovoltaic MPPT circuit and the PFC circuit. The control between the energy storage system and the air conditioning system is carried out through the switch circuit, without a voltage conversion link, reducing the conversion loss. Through this topology, the control system is simplified and the energy efficiency of the system is improved.

[0058] In some embodiments, the control module controls the opening and closing of the first switch, the second switch, and the third switch in combination with the photovoltaic voltage of the photovoltaic assembly, the output voltage of the energy storage system, the remaining power of the energy storage system, and the bus voltage of the power supply bus, and controls the opening and closing of the photovoltaic MPPT unit and the PFC unit in combination to control at least one of the following: whether the photovoltaic air-conditioning system works, whether the photovoltaic assembly is powered, whether the mains is powered, and the charging or discharging operation of the energy storage system, and also includes: the control process when only the energy storage system is charged, which is as follows:

[0059] The control module is further used to control the first switch to close after the photovoltaic assembly is powered on, set the target voltage to the output voltage of the energy storage system, start the photovoltaic MPPT unit or the PFC unit, and determine whether the absolute value of the difference between the output voltage of the energy storage system and the bus voltage of the power supply bus is less than a preset voltage error. The preset voltage error is, for example, 5V.

[0060] The control module is further specifically used to control the third switch to close if it is determined that the absolute value of the difference between the output voltage of the energy storage system and the bus voltage of the power supply bus is less than a preset voltage error, so as to start the charging mode of the energy storage system and charge the battery in the energy storage system; at this time, the working mode of charging only the energy storage system is executed.

[0061] The control module is also specifically used for, in the charging mode of the energy storage system, if it is determined that the remaining power of the energy storage system is less than or equal to the preset charging power threshold, then adopting a preset constant current control strategy to control the charging operation of the energy storage system; if it is determined that the remaining power of the energy storage system is greater than the preset charging power threshold, then adopting a preset constant voltage control strategy to control the charging operation of the energy storage system; if it is determined that the remaining power of the energy storage system is equal to the preset full power threshold, then controlling the third switch to disconnect, controlling the started photovoltaic MPPT unit or the PFC unit to stop working, and completing the charging of the battery. Among them, the preset charging power threshold is such as the power when the battery's state of charge is 95, and the preset full power threshold is such as the power when the battery's state of charge is 100.

[0062] Working mode 1 of the household solar energy storage system: the air conditioning system is not working and the energy storage system is charging. Figure 5 Figure 1 is a flow chart of the pure charging mode of the energy storage system. Figure 5 As shown in the figure, the process of pure charging mode of the energy storage system includes:

[0063] Step 11, the photovoltaic module is powered on, the switch circuit K1 is closed, the target voltage is set to VDC3, the photovoltaic MPPT circuit is started (of course, the switch circuit K2 can also be closed to start the PFC circuit), the energy storage system is the only load, and then step 12 is executed.

[0064] Step 12: The photovoltaic voltage VDC1 output by the photovoltaic module charges the energy storage system through the photovoltaic MPPT circuit. The target voltage of the photovoltaic MPPT circuit is adjusted to achieve the goal of controlling the charging current of the battery. When it is determined that |VDC3-VDC4|<5V is satisfied, execute step 13.

[0065] Step 13, when |VDC3-VDC4|<5V, the switch circuit K3 is closed and the battery charging mode is started: when the battery state of charge SOC≤95 (the specific value can be determined according to the characteristics of the battery), a constant current control strategy is adopted, and the output current I3 of the battery is used as the negative feedback amount of the photovoltaic MPPT circuit or the PFC circuit for control; when SOC>95, a constant voltage control strategy is adopted; when SOC=100, the switch circuit K3 is disconnected, charging is stopped, and the photovoltaic MPPT circuit stops working at the same time, and charging is completed.

[0066] In the solution of the present invention, the voltage and current of the energy storage system are completed by the voltage and current detection unit of the battery management system (BMS) inside the energy storage system, and sent to the external controller of the air-conditioning system through communication to control the charging and discharging of the battery.

[0067] The solution of the present invention, when only the energy storage system is charged, can realize the integrated control of the photovoltaic storage system by controlling the states of the switch circuit K1, the switch circuit K2, the switch circuit K3 and the photovoltaic MPPT circuit and the PFC circuit. The energy storage system and the air-conditioning system are controlled by the switch circuit, without the voltage conversion link, thus reducing the conversion loss. This topology simplifies the control system and improves the energy efficiency of the system.

[0068] In some embodiments, the control module controls the opening and closing of the first switch, the second switch, and the third switch in combination with the photovoltaic voltage of the photovoltaic assembly, the output voltage of the energy storage system, the remaining power of the energy storage system, and the bus voltage of the power supply bus, and controls the opening and closing of the photovoltaic MPPT unit and the PFC unit in combination to control at least one of the following: whether the photovoltaic air-conditioning system works, whether the photovoltaic assembly is powered, whether the mains is powered, and the charging or discharging operation of the energy storage system, and also includes: the control process when only the photovoltaic air-conditioning system is working, which is specifically as follows:

[0069] The control module is further specifically used to control the first switch to be closed after the photovoltaic assembly is powered on; and to control the second switch to be closed after the mains power is powered on.

[0070] The control module is further specifically used to set the target voltage as the output voltage of the energy storage system, start the photovoltaic MPPT unit and the PFC unit, and control the third switch to be disconnected so that the photovoltaic air-conditioning system works and the energy storage system does not work; at this time, a working mode in which only the photovoltaic air-conditioning system works is executed; wherein, based on the set target voltage, the working target voltage of the photovoltaic MPPT unit is further made greater than the target voltage of the PFC unit.

[0071] Working mode 2 of the household solar energy storage system: photovoltaic air conditioning system working. Figure 6 This is a schematic diagram of the working process of the photovoltaic air conditioning system. Figure 6 As shown in the figure, the working process of the photovoltaic air conditioning system includes:

[0072] Step 21, the AC power is turned on, and the switch circuit K2 is closed; the photovoltaic module is powered on, and the switch circuit K1 is closed, and then step 22 is executed.

[0073] Step 22, set the target voltage to VDC3, start the photovoltaic MPPT circuit or PFC circuit, the air conditioning system works, and the energy storage system does not work. At this time, the switch circuit K3 is disconnected, and the photovoltaic MPPT circuit and the mains PFC circuit unit are put into operation. To ensure limited use of photovoltaics, the working target voltage setting value of the photovoltaic power supply circuit can be 10 volts higher than the mains target voltage setting value. For example: the target voltage of the photovoltaic MPPT circuit is set to Vset1, and the target voltage of the mains PFC circuit is set to Vset1-10V.

[0074] The solution of the present invention, when only the photovoltaic air-conditioning system is working, can realize the integrated control of the photovoltaic energy storage system by controlling the states of the switch circuit K1, the switch circuit K2, the switch circuit K3 and the photovoltaic MPPT circuit and the PFC circuit. The energy storage system and the air-conditioning system are controlled by the switch circuit, without the voltage conversion link, thus reducing the conversion loss. This topology simplifies the control system and improves the energy efficiency of the system.

[0075] In some embodiments, the control module controls the opening and closing of the first switch, the second switch, and the third switch in combination with the photovoltaic voltage of the photovoltaic assembly, the output voltage of the energy storage system, the remaining power of the energy storage system, and the bus voltage of the power supply bus, and controls the opening and closing of the photovoltaic MPPT unit and the PFC unit in combination to control at least one of the following: whether the photovoltaic air-conditioning system works, whether the photovoltaic assembly is powered, whether the mains is powered, and the charging or discharging operation of the energy storage system, and also includes: the control process when the photovoltaic air-conditioning system works + the energy storage system is charged, which is as follows:

[0076] The control module is further used to control the first switch to close after the photovoltaic assembly is powered on, set the target voltage to the output voltage of the energy storage system, start the photovoltaic MPPT unit, and determine whether the absolute value of the difference between the output voltage of the energy storage system and the bus voltage of the power supply bus is less than a preset voltage error. The preset voltage error is, for example, 5V.

[0077] The control module is further specifically used to control the third switch to close if it is determined that the absolute value of the difference between the output voltage of the energy storage system and the bus voltage of the power supply bus is less than a preset voltage error, so as to start the charging mode of the energy storage system and charge the battery in the energy storage system; at this time, the photovoltaic component and the energy storage system simultaneously power the photovoltaic air-conditioning system, and execute the working mode of the photovoltaic air-conditioning system working and the energy storage system charging.

[0078] The control module is further specifically used to determine the maximum allowable charging current of the energy storage system according to the power of the photovoltaic component and the power of the photovoltaic air-conditioning system, and control the charging operation of the energy storage system according to the maximum allowable charging current of the energy storage system until the charging of the battery is completed, and then control the third switch to be disconnected and switch to a working mode in which only the photovoltaic air-conditioning system is operated.

[0079] Among them, when executing the working mode in which the photovoltaic air-conditioning system is working and the energy storage system is charging, in the charging mode of the energy storage system, if it is determined that the remaining power of the energy storage system is less than or equal to the preset charging power threshold, the preset constant current control strategy is adopted to control the charging operation of the energy storage system; if it is determined that the remaining power of the energy storage system is greater than the preset charging power threshold, the preset constant voltage control strategy is adopted to control the charging operation of the energy storage system; if it is determined that the remaining power of the energy storage system is equal to the preset full power threshold, the third switch is controlled to be disconnected, the started photovoltaic MPPT unit or the PFC unit is controlled to stop working, the charging of the battery is completed, and the working mode in which only the photovoltaic air-conditioning system is working is switched.

[0080] Working mode 3 of the household solar energy storage system: the air conditioning system is working and the energy storage system is charging. Figure 7 This is a schematic diagram of the charging mode of the energy storage system + the working process of the air conditioning system. Figure 7 As shown in the figure, the charging mode of the energy storage system + the working process of the air conditioning system include:

[0081] Step 31, the photovoltaic module is powered on, the switch circuit K1 is closed, and then step 32 is executed.

[0082] Step 32: Set the target voltage to VDC3, start the photovoltaic MPPT circuit, and when it is determined that |VDC3-VDC4|<5V, execute step 33.

[0083] Step 33, when |VDC3-VDC4|<5V, the switch circuit K3 is closed and charging is started. At this time, the air-conditioning system and the energy storage system work as loads at the same time, and the photovoltaic voltage VDC1 works as an electric energy source. The photovoltaic voltage VDC1 inputs electric energy through the photovoltaic MPPT circuit. It can be seen from the working mode 1 of the household photovoltaic storage system that in order to control the charging current of the battery, it is necessary to adjust the target voltage of the photovoltaic MPPT circuit. If the power of the photovoltaic MPPT circuit is Ps and the power of the air-conditioning system is Pc, the allowable power for charging the energy storage system is Pb=Ps-Pc. The allowable charging current value Is=(Ps-Pc) / Ub of the energy storage system can be calculated through the allowable charging power Pb of the energy storage system. The allowable charging current value Is is set as the target current for control, and the charging current of the energy storage system is controlled as negative feedback to achieve charging control.

[0084] Among them, when the state of charge SOC of the battery is ≤95 (the specific value can be determined according to the characteristics of the battery), a constant current control strategy is adopted, and the output current I3 of the battery is used as the negative feedback amount of the photovoltaic MPPT circuit or PFC circuit for control; when SOC>95, a constant voltage control strategy is adopted; when SOC=100, charging is terminated, the switch circuit K3 is disconnected, and the household solar-storage-air system enters working mode 2.

[0085] According to the solution of the present invention, when the photovoltaic air-conditioning system is working and the energy storage system is charging, the integrated control of the photovoltaic air-storage system can be achieved by controlling the states of the switch circuit K1, the switch circuit K2, and the switch circuit K3 and the photovoltaic MPPT circuit and the PFC circuit. The energy storage system and the air-conditioning system are controlled by the switch circuit without a voltage conversion link, thereby reducing the conversion loss. This topology simplifies the control system and improves the energy efficiency of the system.

[0086] In some embodiments, the control module controls the opening and closing of the first switch, the second switch, and the third switch in combination with the photovoltaic voltage of the photovoltaic assembly, the output voltage of the energy storage system, the remaining power of the energy storage system, and the bus voltage of the power supply bus, and controls the opening and closing of the photovoltaic MPPT unit and the PFC unit in combination to control at least one of the following: whether the photovoltaic air-conditioning system works, whether the photovoltaic assembly is powered, whether the mains is powered, and the charging or discharging operation of the energy storage system, and also includes: the control process when the photovoltaic air-conditioning system works + the energy storage system is discharged, which is as follows:

[0087] The control module is specifically used to control the first switch to close after the photovoltaic component is powered on, set the target voltage to the output voltage of the energy storage system, start the photovoltaic MPPT unit, and determine whether the absolute value of the difference between the output voltage of the energy storage system and the bus voltage of the power supply bus is less than a preset voltage error; wherein the preset voltage error is, for example, 5V.

[0088] The control module is further specifically used to control the third switch to close if it is determined that the absolute value of the difference between the output voltage of the energy storage system and the bus voltage of the power supply bus is less than a preset voltage error, so as to start the discharge mode of the energy storage system and discharge the battery in the energy storage system; at this time, the photovoltaic assembly and the energy storage system simultaneously supply power to the photovoltaic air-conditioning system or the energy storage system alone supplies power to the photovoltaic air-conditioning system, and the photovoltaic air-conditioning system is in operation and the energy storage system is discharged.

[0089] The control module is specifically used to determine the maximum allowable output current of the photovoltaic component according to the power of the photovoltaic component and the power of the photovoltaic air-conditioning system, and control the discharge operation of the energy storage system according to the maximum allowable output current of the photovoltaic component, until the discharge current of the energy storage system is less than 0 and the power of the photovoltaic component is greater than the power of the photovoltaic air-conditioning system, and then switch to the working mode in which the photovoltaic air-conditioning system is operated and the energy storage system is charged.

[0090] Working mode 4 of the household solar energy storage system: the air conditioning system works and the energy storage system discharges. Figure 8 This is a schematic diagram of the discharge mode of the energy storage system + the operation flow of the air conditioning system. Figure 8 As shown in the figure, the discharge mode of the energy storage system + the working process of the air conditioning system include:

[0091] Step 41 , the photovoltaic module is powered on, the switch circuit K1 is closed, and then step 42 is executed.

[0092] Step 42, set the target voltage to VDC3, start the photovoltaic MPPT circuit, and when it is determined that |VDC3-VDC4|<5V, execute step 33.

[0093] Step 33: When |VDC3-VDC4|<5V, the switch circuit K3 is closed, and then step 34 is executed.

[0094] Step 34, in this mode, the mains does not participate in the power supply. It is mainly when the photovoltaic voltage is insufficient or there is no photovoltaic voltage. In order to meet the requirements allowed by the air-conditioning system, the electric energy released by the energy storage system is used for the operation of the air-conditioning system. In this mode, the photovoltaic components and the energy storage system may be powered at the same time, or the energy storage system may be powered alone. Since the energy storage battery is directly connected to the system bus voltage, when the switch circuit K3 is energized, VDC3=VDC4. At this time, the target voltage Vset of the photovoltaic MPPT circuit is set to 5 volts greater than the battery voltage Vb of the energy storage system. Since the photovoltaic voltage is insufficient at this time, the power Ps of the photovoltaic component is less than the power Pc of the air-conditioning system, and the output voltage of the photovoltaic component cannot reach the target value. At the same time, the effect of preferential use of photovoltaic energy can be achieved. Calculate the charging allowable current value Is=(Ps-Pc) / Ub of the energy storage system, set the charging allowable current value Is as the target current for control, and control the charging current of the energy storage system as negative feedback to achieve charging control.

[0095] Due to the instability of photovoltaic voltage, in order to ensure the stability of air-conditioning system operation, the current of the energy storage system needs to be detected in real time: when the output current I3 of the energy storage system is large, it means that the power Ps of the photovoltaic module is less than the power Pc of the air-conditioning system; when the output current I3 of the energy storage system is equal to 0, it means that the power Ps of the photovoltaic module is equal to the power Pc of the air-conditioning system. When the output current I3 of the energy storage system is converted into input current, it means that the power Ps of the photovoltaic module is greater than the power Pc of the air-conditioning system, and the system has entered the charging mode. At this time, the household photovoltaic storage system needs to be adjusted from working mode 4 to working mode 3 as soon as possible. If there is no photovoltaic voltage, the requirement that the power Ps of the photovoltaic module is less than the power Pc of the air-conditioning system is still met, and control can be performed according to this mode.

[0096] According to the solution of the present invention, when the photovoltaic air-conditioning system is working and the energy storage system is discharging, the integrated control of the photovoltaic air-storage system can be achieved by controlling the states of the switch circuit K1, the switch circuit K2, and the switch circuit K3 and the photovoltaic MPPT circuit and the PFC circuit. The energy storage system and the air-conditioning system are controlled by the switch circuit without a voltage conversion link, thereby reducing the conversion loss. This topology simplifies the control system and improves the energy efficiency of the system.

[0097] In summary, in the entire household solar-energy storage system, the indoor unit and outdoor unit of the air-conditioning system are the loads of the entire household solar-energy storage system. When the air-conditioning system is turned on, electricity will be consumed; the photovoltaic system and the power grid system are the power supply part of the entire household solar-energy storage system, which can provide electricity for the air-conditioning system; the energy storage system is relatively special, and it has two working modes. When it works in charging mode, it needs to consume electricity, which is equivalent to a load. When it works in discharging mode, it can provide electricity to the load, which is equivalent to a power supply. Therefore, according to the system working mode and the functions of each part, the household solar-energy storage system can be divided into multiple working modes. If classified according to the source and load modes, it can be divided into four modes: working mode 1, working mode 2, working mode 3 and working mode 4.

[0098] In the scheme of the present invention, the energy storage system and the external controller interact by means of communication to protect the battery cells and perform charging and discharging control. In the scheme of the present invention, the charging and discharging of the battery of the energy storage system, the photovoltaic conversion of the photovoltaic module, and the operation of the air-conditioning system are all centrally controlled by the external controller of the air-conditioning system. The external controller determines the charging and discharging operation of the battery according to the photovoltaic intensity of the photovoltaic module, the state of the battery, and the operating state of the air-conditioning system, thereby reducing the power conversion links and improving the energy utilization efficiency.

[0099] In the solution of the present invention, the bidirectional DC-DC inverter controlled by the energy storage system is eliminated, and the charging and discharging of the energy storage system are controlled by the photovoltaic MPPT circuit of the built-in control unit of the air-conditioning system (i.e., photovoltaic air-conditioning) and the PFC circuit of the mains. The energy storage system exchanges data with the built-in control unit of the air-conditioning system through communication, reducing the voltage conversion link between the energy storage system and the air-conditioning system, thereby reducing the power conversion link and improving energy utilization efficiency, such as increasing the energy efficiency of the entire household photovoltaic storage system by more than 5%. At the same time, due to the elimination of the bidirectional DC-DC inverter controlled by the energy storage system, not only the cost is saved, but also the installation space and installation time of the customer are saved.

[0100] Fig. 9 The figure is a schematic diagram of the conversion efficiency of the energy storage system for charging and discharging, where the horizontal axis is power in kW and the vertical axis is efficiency. Fig. 9 As shown, the maximum conversion efficiency of the bidirectional DC-DC inverter controlled by the energy storage system is about 97%, and the loss after charging and discharging reaches 6%. The solution of the present invention cancels the bidirectional DC-DC inverter controlled by the energy storage system, reduces the voltage conversion link between the energy storage system and the air-conditioning system, and improves the energy efficiency of the entire household photovoltaic storage system by more than 5%, and 5% is a conservative figure.

[0101] According to the technical solution of the present invention, in view of the situation that the external input source of the photovoltaic air-conditioning system is the photovoltaic module, the energy storage system and the mains, a first switch and a photovoltaic MPPT circuit connected between the photovoltaic module and the power supply bus, a second switch connected between the mains and the photovoltaic module, a rectifier bridge and a PFC circuit, a switching power supply connected to the power supply bus, other loads inside the air conditioner, a compressor connected to the power supply bus via a first inverter, an external fan connected to the power supply bus via a second inverter are arranged in the outdoor unit and the control unit, an indoor fan connected to the power supply bus via a third inverter is arranged in the indoor unit and the control unit, and a battery connected to the power supply bus via a third switch is arranged in the energy storage and control unit; when working, the outdoor unit controller determines the charging and discharging operation of the battery according to the photovoltaic intensity of the photovoltaic module, the state of the battery and the operating state of the air-conditioning system; thereby, by eliminating the voltage conversion unit (such as a bidirectional DC-DC inverter) between the energy storage system and the air-conditioning system, the voltage conversion link between the energy storage system and the air-conditioning system is reduced, and the energy utilization efficiency is improved.

[0102] According to an embodiment of the present invention, a photovoltaic air conditioning system corresponding to the power supply control device of the photovoltaic air conditioning system is also provided. The photovoltaic air conditioning system may include: the power supply control device of the photovoltaic air conditioning system described above.

[0103] Since the processing and functions implemented by the photovoltaic air-conditioning system of this embodiment basically correspond to the embodiments, principles and examples of the device, for the details not described in this embodiment, please refer to the relevant descriptions in the aforementioned embodiments and will not be repeated here.

[0104] According to an embodiment of the present invention, a power supply control method for a photovoltaic air conditioning system corresponding to the photovoltaic air conditioning system is also provided. Fig.10 The schematic flow chart of an embodiment of the method of the present invention is shown. The power supply control method of the photovoltaic air conditioning system may include: step S110 to step S120.

[0105] In step S110, the photovoltaic voltage of the photovoltaic module is obtained, the output voltage of the energy storage system is obtained, the remaining power of the energy storage system is obtained, and the bus voltage of the power supply bus is obtained. The photovoltaic voltage of the photovoltaic module is such as voltage VDC1, the output voltage of the energy storage system is such as voltage VDC3, the remaining power of the energy storage system is such as the state of charge SOC of the battery, and the bus voltage of the power supply bus is such as DC bus voltage VDC4.

[0106] At step S120, the first switch, the second switch and the third switch are controlled to be turned on and off in combination with the photovoltaic voltage of the photovoltaic component, the output voltage of the energy storage system, the remaining power of the energy storage system, and the bus voltage of the power supply bus, and the photovoltaic MPPT unit and the PFC unit are controlled to be turned on and off in combination to control at least one of the following: whether the photovoltaic air-conditioning system is working, whether the photovoltaic component is powered, whether the mains is powered, and the charging or discharging operation of the energy storage system.

[0107] The solution of the present invention eliminates the bidirectional DC-DC inverter controlled by the energy storage system. The charging and discharging of the energy storage system are controlled by the photovoltaic MPPT circuit of the built-in control unit of the air-conditioning system (i.e., photovoltaic air-conditioning system) and the PFC circuit of the mains. The energy storage system exchanges data with the built-in control unit of the air-conditioning system through communication, reducing the voltage conversion link between the energy storage system and the air-conditioning system, thereby reducing the power conversion link and improving energy utilization efficiency. At the same time, due to the elimination of the bidirectional DC-DC inverter controlled by the energy storage system, not only the cost is saved, but also the installation space and installation time of the customer are saved.

[0108] In some embodiments, the voltage selection of the energy storage system is determined according to the required voltage of the power supply bus of the photovoltaic air conditioning system. The rated voltage of the energy storage system needs to be equal to the rated working voltage of the photovoltaic air conditioning system; the maximum voltage allowed by the energy storage system needs to be less than the maximum working voltage allowed by the internal controller hardware and load unit of the photovoltaic air conditioning system, and the external controller hardware and load unit of the photovoltaic air conditioning system.

[0109] exist Figure 4 In the example shown, the design of the energy storage and control unit is the key to the operation of the entire household solar energy storage system. Since the output voltage VDC3 of the battery in the energy storage system is directly connected to the bus voltage VDC4 of the air conditioning system, the bus voltage of the energy storage system needs to meet the operating requirements of the air conditioning system. If the rated operating voltage of the air conditioning system is V an , then the rated voltage value of the energy storage system is V cn It should also be designed in this way, that is, V cn =V an Only in this way can the voltage of the energy storage system and the bus voltage of the air conditioning system be directly connected without the need for a conversion unit. Take the example of selecting lithium iron phosphate batteries for energy storage units (lithium titanate or ternary lithium batteries can also be selected). Since the voltage of the battery is different under different states of charge, the rated voltage of a single cell is 3.2 volts, and the voltage of a single cell when fully charged is about 3.65 volts. If the rated voltage of the energy storage system is 371.2 volts, the maximum operating voltage after full charge is 423.4 volts. Therefore, when designing an energy storage system, it is necessary to consider the maximum voltage V of the energy storage system when the battery is fully charged. bmax It needs to be smaller than the maximum operating voltage V allowed by the indoor unit and control unit, outdoor unit and control unit of the air conditioning system. amax , that is, V bmax ≤V amax .

[0110] In the related schemes, the battery of the energy storage system was designed without considering the needs of the air conditioning system. The energy storage system and the air conditioning system were designed independently, and both needed to be converted twice through DC-DC. In the related schemes, the charging and discharging of the energy storage cabinet must pass through DC-DC. However, in the scheme of the present invention, the energy storage system does not need DC-DC, and the charging and discharging of the energy storage cabinet are controlled by the external mainboard of the air conditioning system. The external mainboard of the air conditioning system not only integrates the photovoltaic MPPT circuit, but also has the charging and discharging control functions. In the scheme of the present invention, the photovoltaic MPPT circuit and the external controller of the air conditioning system are integrated to realize single-core control, and the DC-DC of the energy storage part is eliminated at the same time, and the DC-DC related to the energy storage is integrated and controlled through the external controller of the air conditioning system.

[0111] In some embodiments, in step S120, the photovoltaic voltage of the photovoltaic component, the output voltage of the energy storage system, the remaining power of the energy storage system, and the bus voltage of the power supply bus are combined to control the opening and closing of the first switch, the second switch, and the third switch, and the opening and closing of the photovoltaic MPPT unit and the PFC unit are combined to control at least one of the following: whether the photovoltaic air-conditioning system is working, whether the photovoltaic component is powered, whether the mains is powered, and the charging or discharging operation of the energy storage system, including: a process of controlling based on the maximum voltage allowed by the photovoltaic air-conditioning system, specifically including at least one of the following control situations.

[0112] The first control scenario: when the first switch is closed, if the photovoltaic voltage of the photovoltaic component is greater than the maximum voltage allowed by the photovoltaic air-conditioning system, the first switch is controlled to be disconnected; wherein the maximum voltage allowed by the photovoltaic air-conditioning system is the maximum operating voltage allowed by the indoor load unit and the outdoor load unit.

[0113] The second control situation: when the second switch is closed, if the input voltage of the mains is greater than the maximum voltage allowed by the photovoltaic air-conditioning system, the second switch is controlled to be opened.

[0114] The third control scenario: when the third switch is closed, if the bus voltage of the power supply bus is greater than the maximum voltage allowed by the energy storage system, the third switch is controlled to be open.

[0115] exist Figure 4 In the example shown, the switch circuit K1 controls the input of the solar photovoltaic power source; the switch circuit K2 controls the input of the mains power; and the switch circuit K3 controls whether the battery is connected to the air conditioning system. When it is detected that the photovoltaic input voltage VDC1 is greater than the maximum voltage allowed by the entire household photovoltaic energy storage system, the switch circuit K1 is disconnected; when it is detected that the mains power input voltage VDC2 is greater than the maximum voltage allowed by the entire household photovoltaic energy storage system, the switch circuit K2 is disconnected; if it is detected that the system bus voltage VDC4 is greater than the maximum voltage allowed by the energy storage system V bmax When VDC4>V bmax To ensure the safety of the battery, the switch circuit K3 is disconnected.

[0116] In the solution of the present invention, in order to prevent external overvoltage, the external controller detects the input photovoltaic voltage. When the photovoltaic voltage exceeds the allowable voltage, the switch connected to the photovoltaic module is disconnected, and the photovoltaic voltage is not connected to the external power supply system (i.e., the power supply system controlled by the external controller); only when the photovoltaic overvoltage meets the set requirements, the switch connected to the photovoltaic module is closed, and the photovoltaic voltage is connected to the external power supply system, thereby improving safety.

[0117] The solution of the present invention, in the topology of the light-storage-air system, eliminates the DC-DC between the energy storage system and the air conditioner, and the bus of the air conditioner is connected to the bus of the energy storage cabinet through the switch circuit K3; the photovoltaic MPPT circuit between the photovoltaic part and the air conditioning system is eliminated, and the photovoltaic MPPT circuit is integrated into the external controller of the air conditioning system; the charging and discharging control of the energy storage system is realized by controlling the photovoltaic MPPT circuit and the switch circuit K3. Under different working states of the air conditioning system, the integrated control of the light-storage-air system can be realized by controlling the states of the switch circuit K1, the switch circuit K2, the switch circuit K3 and the photovoltaic MPPT circuit and the PFC circuit. The control between the energy storage system and the air conditioning system is carried out through the switch circuit, without a voltage conversion link, reducing the conversion loss. Through this topology, the control system is simplified and the energy efficiency of the system is improved.

[0118] In some embodiments, in step S120, the photovoltaic voltage of the photovoltaic component, the output voltage of the energy storage system, the remaining power of the energy storage system, and the bus voltage of the power supply bus are combined to control the opening and closing of the first switch, the second switch, and the third switch, and the opening and closing of the photovoltaic MPPT unit and the PFC unit are combined to control at least one of the following: whether the photovoltaic air-conditioning system is working, whether the photovoltaic component is powered, whether the mains is powered, and the charging or discharging operation of the energy storage system, and also includes: a control process when only the energy storage system is charged.

[0119] Combine the following Fig.11 The flowchart of an embodiment of the control in the method of the present invention when only the energy storage system is charged is shown, which further illustrates the specific process of the control in step S120 when only the energy storage system is charged, including; step S210 to step S230.

[0120] Step S210, after the photovoltaic assembly is powered on, the first switch is controlled to close, the target voltage is set to the output voltage of the energy storage system, the photovoltaic MPPT unit or the PFC unit is started, and it is determined whether the absolute value of the difference between the output voltage of the energy storage system and the bus voltage of the power supply bus is less than a preset voltage error. The preset voltage error is, for example, 5V.

[0121] Step S220: If it is determined that the absolute value of the difference between the output voltage of the energy storage system and the bus voltage of the power supply bus is less than a preset voltage error, the third switch is controlled to close to start the charging mode of the energy storage system to charge the battery in the energy storage system; at this time, the working mode of charging only the energy storage system is executed.

[0122] Step S230, in the charging mode of the energy storage system, if it is determined that the remaining power of the energy storage system is less than or equal to the preset charging power threshold, the preset constant current control strategy is used to control the charging operation of the energy storage system; if it is determined that the remaining power of the energy storage system is greater than the preset charging power threshold, the preset constant voltage control strategy is used to control the charging operation of the energy storage system; if it is determined that the remaining power of the energy storage system is equal to the preset full power threshold, the third switch is controlled to be disconnected, and the started photovoltaic MPPT unit or the PFC unit is controlled to stop working, so as to complete the charging of the battery. Among them, the preset charging power threshold is such as the power when the battery's state of charge is 95, and the preset full power threshold is such as the power when the battery's state of charge is 100.

[0123] Working mode 1 of the household solar energy storage system: the air conditioning system is not working and the energy storage system is charging. Figure 5 Figure 1 is a flow chart of the pure charging mode of the energy storage system. Figure 5 As shown in the figure, the process of pure charging mode of the energy storage system includes:

[0124] Step 11, the photovoltaic module is powered on, the switch circuit K1 is closed, the target voltage is set to VDC3, the photovoltaic MPPT circuit is started (of course, the switch circuit K2 can also be closed to start the PFC circuit), the energy storage system is the only load, and then step 12 is executed. Among them, the initial target voltage is set to VD3 in order to attract the relay K3, and different voltages are set later to achieve priority use of electric energy, and the target voltage with a higher target voltage will be used first.

[0125] Step 12: The photovoltaic voltage VDC1 output by the photovoltaic module charges the energy storage system through the photovoltaic MPPT circuit. The target voltage of the photovoltaic MPPT circuit is adjusted to achieve the goal of controlling the charging current of the battery. When it is determined that |VDC3-VDC4|<5V is satisfied, execute step 13.

[0126] Step 13, when |VDC3-VDC4|<5V, the switch circuit K3 is closed and the battery charging mode is started: when the battery state of charge SOC≤95 (the specific value can be determined according to the characteristics of the battery), a constant current control strategy is adopted, and the current is determined by the photovoltaic power generation power and the load power. During charging, the charging voltage shall not be greater than the maximum voltage allowed by the battery system. The output current I3 of the battery is used as the negative feedback amount of the photovoltaic MPPT circuit or the PFC circuit for control, and the current is controlled by adjusting the bus voltage; when SOC>95, a constant voltage control strategy is adopted, and the highest voltage of the energy storage system is used as the target voltage for control; when SOC=100, the switch circuit K3 is disconnected, charging is stopped, and the photovoltaic MPPT circuit stops working at the same time, and charging is completed.

[0127] In the solution of the present invention, the voltage and current of the energy storage system are completed by the voltage and current detection unit of the battery management system (BMS) inside the energy storage system, and sent to the external controller of the air-conditioning system through communication to control the charging and discharging of the battery.

[0128] The solution of the present invention, when only the energy storage system is charged, can realize the integrated control of the photovoltaic storage system by controlling the states of the switch circuit K1, the switch circuit K2, the switch circuit K3 and the photovoltaic MPPT circuit and the PFC circuit. The energy storage system and the air-conditioning system are controlled by the switch circuit, without the voltage conversion link, thus reducing the conversion loss. This topology simplifies the control system and improves the energy efficiency of the system.

[0129] In some embodiments, in step S120, the photovoltaic voltage of the photovoltaic component, the output voltage of the energy storage system, the remaining power of the energy storage system, and the bus voltage of the power supply bus are combined to control the opening and closing of the first switch, the second switch, and the third switch, and the opening and closing of the photovoltaic MPPT unit and the PFC unit are combined to control at least one of the following: whether the photovoltaic air-conditioning system is working, whether the photovoltaic component is powered, whether the mains is powered, and the charging or discharging operation of the energy storage system, and also includes: a control process when only the photovoltaic air-conditioning system is working.

[0130] Combine the following Fig.12 The flowchart of an embodiment of the control in the method of the present invention when only the photovoltaic air-conditioning system is working is shown, which further illustrates the specific process of the control in step S120 when only the photovoltaic air-conditioning system is working, including: step S310 to step S320.

[0131] Step S310, after the photovoltaic assembly is powered on, controlling the first switch to be closed; after the mains power is powered on, controlling the second switch to be closed.

[0132] Step S320, setting the target voltage of the photovoltaic MPPT unit and the target voltage of the PFC unit (i.e., the mains PFC circuit), starting the photovoltaic MPPT unit and the PFC unit, and controlling the third switch to disconnect so that the photovoltaic air-conditioning system works and the energy storage system does not work; at this time, the working mode in which only the photovoltaic air-conditioning system works is executed; wherein, in order to achieve the purpose of giving priority to the voltage of the photovoltaic module, that is, in order to achieve the purpose of giving priority to the use of photovoltaic energy, the working target voltage of the photovoltaic MPPT unit is further made greater than the target voltage of the PFC unit.

[0133] Working mode 2 of the household solar energy storage system: photovoltaic air conditioning system working. Figure 6 This is a schematic diagram of the working process of the photovoltaic air conditioning system. Figure 6 As shown in the figure, the working process of the photovoltaic air conditioning system includes:

[0134] Step 21, the AC power is turned on, and the switch circuit K2 is closed; the photovoltaic module is powered on, and the switch circuit K1 is closed, and then step 22 is executed.

[0135] Step 22, set the target voltage of the photovoltaic MPPT unit and the target voltage of the mains PFC unit, start the photovoltaic MPPT circuit or PFC circuit, the air conditioning system works, and the energy storage system does not work. At this time, the switch circuit K3 is disconnected, and the photovoltaic MPPT circuit and the mains PFC circuit unit are put into operation. To ensure limited use of photovoltaics, the working target voltage setting value of the photovoltaic power supply circuit can be 10 volts higher than the mains target voltage setting value. For example: the target voltage of the photovoltaic MPPT circuit is set to Vset1, and the target voltage of the mains PFC circuit is set to Vset1-10V.

[0136] The solution of the present invention, when only the photovoltaic air-conditioning system is working, can realize the integrated control of the photovoltaic energy storage system by controlling the states of the switch circuit K1, the switch circuit K2, the switch circuit K3 and the photovoltaic MPPT circuit and the PFC circuit. The energy storage system and the air-conditioning system are controlled by the switch circuit, without the voltage conversion link, thus reducing the conversion loss. This topology simplifies the control system and improves the energy efficiency of the system.

[0137] In some embodiments, in step S120, the photovoltaic voltage of the photovoltaic component, the output voltage of the energy storage system, the remaining power of the energy storage system, and the bus voltage of the power supply bus are combined to control the opening and closing of the first switch, the second switch, and the third switch, and the opening and closing of the photovoltaic MPPT unit and the PFC unit are combined to control at least one of the following: whether the photovoltaic air-conditioning system is working, whether the photovoltaic component is powered, whether the mains is powered, and the charging or discharging operation of the energy storage system, and also includes: the control process when the photovoltaic air-conditioning system is working + the energy storage system is charging.

[0138] Combine the following Fig.13 The flowchart of an embodiment of the control in the method of the present invention when the photovoltaic air-conditioning system is working + the energy storage system is charging is shown, which further illustrates the specific process of control in step S120 when the photovoltaic air-conditioning system is working + the energy storage system is charging, including: step S410 to step S430.

[0139] Step S410, after the photovoltaic assembly is powered on, the first switch is controlled to close, the target voltage is set to the output voltage of the energy storage system, the photovoltaic MPPT unit is started, and it is determined whether the absolute value of the difference between the output voltage of the energy storage system and the bus voltage of the power supply bus is less than a preset voltage error. The preset voltage error is, for example, 5V.

[0140] Step S420, if it is determined that the absolute value of the difference between the output voltage of the energy storage system and the bus voltage of the power supply bus is less than a preset voltage error, the third switch is controlled to close to start the charging mode of the energy storage system to charge the battery in the energy storage system; at this time, the photovoltaic assembly and the energy storage system simultaneously supply power to the photovoltaic air-conditioning system, executing the working mode of the photovoltaic air-conditioning system working and the energy storage system charging.

[0141] Step S430, determining the maximum allowable charging current of the energy storage system according to the power of the photovoltaic module and the power of the photovoltaic air-conditioning system, and controlling the charging operation of the energy storage system according to the maximum allowable charging current of the energy storage system until the charging of the battery is completed, and then controlling the third switch to disconnect and switch to the working mode in which only the photovoltaic air-conditioning system works.

[0142] Among them, when executing the working mode in which the photovoltaic air-conditioning system is working and the energy storage system is charging, in the charging mode of the energy storage system, if it is determined that the remaining power of the energy storage system is less than or equal to the preset charging power threshold, the preset constant current control strategy is adopted to control the charging operation of the energy storage system; if it is determined that the remaining power of the energy storage system is greater than the preset charging power threshold, the preset constant voltage control strategy is adopted to control the charging operation of the energy storage system; if it is determined that the remaining power of the energy storage system is equal to the preset full power threshold, the third switch is controlled to be disconnected, the started photovoltaic MPPT unit or the PFC unit is controlled to stop working, the charging of the battery is completed, and the working mode in which only the photovoltaic air-conditioning system is working is switched.

[0143] Working mode 3 of the household solar energy storage system: the air conditioning system is working and the energy storage system is charging. Figure 7 This is a schematic diagram of the charging mode of the energy storage system + the working process of the air conditioning system. Figure 7 As shown in the figure, the charging mode of the energy storage system + the working process of the air conditioning system include:

[0144] Step 31, the photovoltaic module is powered on, the switch circuit K1 is closed, and then step 32 is executed.

[0145] Step 32, set the target voltage of the photovoltaic MPPT unit to VD3, in order to make the bus voltage and the energy storage system voltage close to each other and realize the pull-in of relay K3; start the photovoltaic MPPT circuit, and when it is determined that |VDC3-VDC4|<5V is satisfied, execute step 33.

[0146] Step 33, when |VDC3-VDC4|<5V, the switch circuit K3 is closed and charging is started. At this time, the air conditioning system and the energy storage system work as loads at the same time, and the photovoltaic voltage VDC1 works as an electric energy source. The photovoltaic voltage VDC1 inputs electric energy through the photovoltaic MPPT circuit. It can be seen from the working mode 1 of the household light-storage air system that in order to control the charging current of the battery, the target voltage of the photovoltaic MPPT circuit needs to be adjusted. If the power of the photovoltaic MPPT circuit is Ps and the power of the air conditioning system is Pc, the allowable power for charging the energy storage system is Pb=Ps-Pc. The charging allowable current value Is=(Ps-Pc) / Ub of the energy storage system can be calculated through the charging allowable power Pb of the energy storage system. The charging allowable current value Is is set as the target current for control, and the charging current of the energy storage system is controlled as negative feedback, so that the charging control can be achieved. Among them, Ub is the voltage of the battery. PID control is adopted here, and the voltage is adjusted by the current. When the voltage increases, the current increases, and when the voltage decreases, the current decreases, so as to achieve the goal of controlling the current.

[0147] Among them, when the state of charge SOC of the battery is ≤95 (the specific value can be determined according to the characteristics of the battery), a constant current control strategy is adopted, and the output current I3 of the battery is used as the negative feedback amount of the photovoltaic MPPT circuit or PFC circuit for control; when SOC>95, a constant voltage control strategy is adopted; when SOC=100, charging is terminated, the switch circuit K3 is disconnected, and the household solar-storage-air system enters working mode 2.

[0148] According to the solution of the present invention, when the photovoltaic air-conditioning system is working and the energy storage system is charging, the integrated control of the photovoltaic air-storage system can be achieved by controlling the states of the switch circuit K1, the switch circuit K2, and the switch circuit K3 and the photovoltaic MPPT circuit and the PFC circuit. The energy storage system and the air-conditioning system are controlled by the switch circuit without a voltage conversion link, thereby reducing the conversion loss. This topology simplifies the control system and improves the energy efficiency of the system.

[0149] In some embodiments, in step S120, the photovoltaic voltage of the photovoltaic component, the output voltage of the energy storage system, the remaining power of the energy storage system, and the bus voltage of the power supply bus are combined to control the opening and closing of the first switch, the second switch, and the third switch, and the opening and closing of the photovoltaic MPPT unit and the PFC unit are combined to control at least one of the following: whether the photovoltaic air-conditioning system is working, whether the photovoltaic component is powered, whether the mains is powered, and the charging or discharging operation of the energy storage system, and also includes: the control process when the photovoltaic air-conditioning system is working + the energy storage system is discharging.

[0150] Combine the following Fig.14 The flowchart of an embodiment of the control in the method of the present invention when the photovoltaic air-conditioning system is working + the energy storage system is discharging is shown, which further illustrates the specific process of control in step S120 when the photovoltaic air-conditioning system is working + the energy storage system is discharging, including: step S510 to step S530.

[0151] Step S510, after the photovoltaic assembly is powered on, the first switch is controlled to close, the target voltage is set to the output voltage of the energy storage system, the photovoltaic MPPT unit is started, and it is determined whether the absolute value of the difference between the output voltage of the energy storage system and the bus voltage of the power supply bus is less than a preset voltage error. The preset voltage error is, for example, 5V.

[0152] Step S520: If it is determined that the absolute value of the difference between the output voltage of the energy storage system and the bus voltage of the power supply bus is less than a preset voltage error, the third switch is controlled to close to start the discharge mode of the energy storage system to discharge the battery in the energy storage system; at this time, the photovoltaic assembly and the energy storage system simultaneously supply power to the photovoltaic air-conditioning system or the energy storage system alone supplies power to the photovoltaic air-conditioning system, and the photovoltaic air-conditioning system is executed in a working mode in which the energy storage system is in operation and the energy storage system is discharged.

[0153] Step S530, according to the power of the photovoltaic module and the power of the photovoltaic air-conditioning system, determine the maximum allowable output current of the photovoltaic module, and control the discharge operation of the energy storage system according to the maximum allowable output current of the photovoltaic module, until the discharge current of the energy storage system is less than 0 and the power of the photovoltaic module is greater than the power of the photovoltaic air-conditioning system, and then switch to the working mode of executing the photovoltaic air-conditioning system and charging the energy storage system.

[0154] Working mode 4 of the household solar energy storage system: the air conditioning system works and the energy storage system discharges. Figure 8 This is a schematic diagram of the discharge mode of the energy storage system + the operation flow of the air conditioning system. Figure 8As shown in the figure, the discharge mode of the energy storage system + the working process of the air conditioning system include:

[0155] Step 41 , the photovoltaic module is powered on, the switch circuit K1 is closed, and then step 42 is executed.

[0156] Step 42, setting the target voltage of the photovoltaic MPPT circuit to VDC3, that is, setting the rated target voltage of photovoltaic and mains, the purpose is to make the bus voltage and the energy storage system voltage close to each other, so as to realize the attraction of relay K3; starting the photovoltaic MPPT circuit, and when it is determined that |VDC3-VDC4|<5V is satisfied, executing step 33.

[0157] Step 33: When |VDC3-VDC4|<5V, the switch circuit K3 is closed, and then step 34 is executed.

[0158] Step 34, in this mode, the mains does not participate in the power supply. It is mainly when the photovoltaic voltage is insufficient or there is no photovoltaic voltage. In order to meet the requirements allowed by the air-conditioning system, the electric energy released by the energy storage system is used for the operation of the air-conditioning system. In this mode, the photovoltaic components and the energy storage system may be powered at the same time, or the energy storage system may be powered alone. Since the energy storage battery is directly connected to the system bus voltage, when the switch circuit K3 is energized, VDC3=VDC4. At this time, the target voltage Vset of the photovoltaic MPPT circuit is set to a value 5 volts greater than the battery voltage Vb of the energy storage system. Since the photovoltaic voltage is insufficient at this time, the power Ps of the photovoltaic component is less than the power Pc of the air-conditioning system, and the output voltage of the photovoltaic component cannot reach the target value. At the same time, the effect of giving priority to the use of photovoltaic energy can be achieved. Calculate the current value Is=(Ps-Pc) / Ub required for the energy storage system to be discharged, set the current value Is required to be discharged as the target current for control, and control the discharge current of the energy storage system as negative feedback to achieve control of the discharge.

[0159] Due to the instability of photovoltaic voltage, in order to ensure the stability of air-conditioning system operation, the current of the energy storage system needs to be detected in real time: when the output current I3 of the energy storage system is large, it means that the power Ps of the photovoltaic module is less than the power Pc of the air-conditioning system; when the output current I3 of the energy storage system is equal to 0, it means that the power Ps of the photovoltaic module is equal to the power Pc of the air-conditioning system. When the output current I3 of the energy storage system is converted into input current, it means that the power Ps of the photovoltaic module is greater than the power Pc of the air-conditioning system, and the system has entered the charging mode. At this time, the household photovoltaic storage system needs to be adjusted from working mode 4 to working mode 3 as soon as possible. If there is no photovoltaic voltage, the requirement that the power Ps of the photovoltaic module is less than the power Pc of the air-conditioning system is still met, and control can be performed according to this mode.

[0160] According to the solution of the present invention, when the photovoltaic air-conditioning system is working and the energy storage system is discharging, the integrated control of the photovoltaic air-storage system can be achieved by controlling the states of the switch circuit K1, the switch circuit K2, and the switch circuit K3 and the photovoltaic MPPT circuit and the PFC circuit. The energy storage system and the air-conditioning system are controlled by the switch circuit without a voltage conversion link, thereby reducing the conversion loss. This topology simplifies the control system and improves the energy efficiency of the system.

[0161] In summary, in the entire household solar-energy storage system, the indoor unit and outdoor unit of the air-conditioning system are the loads of the entire household solar-energy storage system. When the air-conditioning system is turned on, electricity will be consumed; the photovoltaic system and the power grid system are the power supply part of the entire household solar-energy storage system, which can provide electricity for the air-conditioning system; the energy storage system is relatively special, and it has two working modes. When it works in charging mode, it needs to consume electricity, which is equivalent to a load. When it works in discharging mode, it can provide electricity to the load, which is equivalent to a power supply. Therefore, according to the system working mode and the functions of each part, the household solar-energy storage system can be divided into multiple working modes. If classified according to the source and load modes, it can be divided into four modes: working mode 1, working mode 2, working mode 3 and working mode 4.

[0162] In the scheme of the present invention, the energy storage system and the external controller interact by means of communication to protect the battery cells and perform charging and discharging control. In the scheme of the present invention, the charging and discharging of the battery of the energy storage system, the photovoltaic conversion of the photovoltaic module, and the operation of the air-conditioning system are all centrally controlled by the external controller of the air-conditioning system. The external controller determines the charging and discharging operation of the battery according to the photovoltaic intensity of the photovoltaic module, the state of the battery, and the operating state of the air-conditioning system, thereby reducing the power conversion links and improving the energy utilization efficiency.

[0163] Since the processing and functions implemented by the method of this embodiment basically correspond to the embodiments, principles and examples of the aforementioned photovoltaic air-conditioning system, for the details not fully described in this embodiment, please refer to the relevant descriptions in the aforementioned embodiments and will not be repeated here.

[0164] In summary, it is easy for those skilled in the art to understand that, under the premise of no conflict, the above-mentioned advantageous methods can be freely combined and superimposed.

[0165] The above description is only an embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent substitution, improvement, etc. made within the spirit and principle of the present invention shall be included in the scope of the claims of the present invention.

Claims

1. A power supply control device for a photovoltaic air conditioning system, characterized in that: The power supply of the photovoltaic air-conditioning system includes: photovoltaic components, energy storage system and mains power, wherein the energy storage system has a battery; on the external unit side of the photovoltaic air-conditioning system, a photovoltaic MPPT unit, a rectifier unit, a PFC unit and an external unit load unit are arranged; on the internal unit side of the photovoltaic air-conditioning system, an internal unit load unit is arranged; after the photovoltaic components are connected to the photovoltaic MPPT unit through a first switch, the mains power is connected to the input side of the power supply bus of the photovoltaic air-conditioning system through a second switch, the rectifier unit and the PFC circuit, and the battery is connected to the input side of the power supply bus of the photovoltaic air-conditioning system through a third switch; the output side of the power supply bus is connected to the external unit load unit and the internal unit load unit respectively; the power supply control device of the photovoltaic air-conditioning system includes: an acquisition module and a control module; wherein, The acquisition module is used to acquire the photovoltaic voltage of the photovoltaic assembly, acquire the output voltage of the energy storage system, acquire the remaining power of the energy storage system, and acquire the bus voltage of the power supply bus; The control module is used to control the opening and closing of the first switch, the second switch and the third switch in combination with the photovoltaic voltage of the photovoltaic component, the output voltage of the energy storage system, the remaining power of the energy storage system, and the bus voltage of the power supply bus, and to control the opening and closing of the photovoltaic MPPT unit and the PFC unit in combination to control at least one of the following: whether the photovoltaic air-conditioning system is working, whether the photovoltaic component is powered, whether the mains is powered, and the charging or discharging operation of the energy storage system.

2. The power supply control device for the photovoltaic air conditioning system according to claim 1, characterized in that: The voltage selection of the energy storage system is determined according to the required voltage of the power supply bus of the photovoltaic air conditioning system; wherein, The rated voltage of the energy storage system needs to be equal to the rated operating voltage of the photovoltaic air conditioning system; The maximum voltage allowed by the energy storage system needs to be smaller than the maximum operating voltage allowed by the hardware and load unit of the indoor controller of the photovoltaic air-conditioning system, and the hardware and load unit of the outdoor controller of the photovoltaic air-conditioning system.

3. A photovoltaic air conditioning system, characterized in that: include: A power supply control device for a photovoltaic air conditioning system as claimed in any one of claims 1 to 2.

4. A control method for a photovoltaic air conditioning system as claimed in claim 3, characterized in that: include: Obtaining the photovoltaic voltage of the photovoltaic assembly, obtaining the output voltage of the energy storage system, obtaining the remaining power of the energy storage system, and obtaining the bus voltage of the power supply bus; In combination with the photovoltaic voltage of the photovoltaic component, the output voltage of the energy storage system, the remaining power of the energy storage system, and the bus voltage of the power supply bus, the opening and closing of the first switch, the second switch, and the third switch are controlled, and in combination with the opening and closing of the photovoltaic MPPT unit and the PFC unit, at least one of the following is controlled: whether the photovoltaic air-conditioning system is working, whether the photovoltaic component is powered, whether the mains is powered, and the charging or discharging operation of the energy storage system.

5. The power supply control method of the photovoltaic air conditioning system according to claim 4, characterized in that: The voltage selection of the energy storage system is determined according to the required voltage of the power supply bus of the photovoltaic air conditioning system; wherein, The rated voltage of the energy storage system needs to be equal to the rated operating voltage of the photovoltaic air conditioning system; The maximum voltage allowed by the energy storage system needs to be smaller than the maximum operating voltage allowed by the hardware and load unit of the indoor controller of the photovoltaic air-conditioning system, and the hardware and load unit of the outdoor controller of the photovoltaic air-conditioning system.

6. The power supply control method of the photovoltaic air conditioning system according to claim 4 or 5, characterized in that: In combination with the photovoltaic voltage of the photovoltaic module, the output voltage of the energy storage system, the remaining power of the energy storage system, and the bus voltage of the power supply bus, the first switch, the second switch, and the third switch are controlled to be turned on and off, and the photovoltaic MPPT unit and the PFC unit are controlled to be turned on and off, so as to control at least one of the following: whether the photovoltaic air-conditioning system works, whether the photovoltaic module is powered, whether the mains is powered, and the charging or discharging operation of the energy storage system, including: When the first switch is closed, if the photovoltaic voltage of the photovoltaic module is greater than the maximum voltage allowed by the photovoltaic air-conditioning system, the first switch is controlled to be disconnected; wherein the maximum voltage allowed by the photovoltaic air-conditioning system is the maximum operating voltage allowed by the indoor load unit and the outdoor load unit; When the second switch is closed, if the input voltage of the mains is greater than the maximum voltage allowed by the photovoltaic air-conditioning system, the second switch is controlled to be opened; When the third switch is closed, if the bus voltage of the power supply bus is greater than the maximum voltage allowed by the energy storage system, the third switch is controlled to be opened.

7. The power supply control method of the photovoltaic air conditioning system according to claim 4 or 5, characterized in that: In combination with the photovoltaic voltage of the photovoltaic module, the output voltage of the energy storage system, the remaining power of the energy storage system, and the bus voltage of the power supply bus, the first switch, the second switch, and the third switch are controlled to be turned on and off, and the photovoltaic MPPT unit and the PFC unit are controlled to be turned on and off to control at least one of the following: whether the photovoltaic air-conditioning system works, whether the photovoltaic module is powered, whether the mains is powered, and the charging or discharging operation of the energy storage system, and also includes: After the photovoltaic assembly is powered on, the first switch is controlled to close, the target voltage is set to the output voltage of the energy storage system, the photovoltaic MPPT unit or the PFC unit is started, and it is determined whether the absolute value of the difference between the output voltage of the energy storage system and the bus voltage of the power supply bus is less than a preset voltage error; If it is determined that the absolute value of the difference between the output voltage of the energy storage system and the bus voltage of the power supply bus is less than a preset voltage error, the third switch is controlled to close to start the charging mode of the energy storage system to charge the battery in the energy storage system; at this time, the working mode of charging only the energy storage system is executed; If it is determined that the remaining power of the energy storage system is less than or equal to the preset charging power threshold, the preset constant current control strategy is adopted to control the charging operation of the energy storage system; if it is determined that the remaining power of the energy storage system is greater than the preset charging power threshold, the preset constant voltage control strategy is adopted to control the charging operation of the energy storage system; if it is determined that the remaining power of the energy storage system is equal to the preset full power threshold, the third switch is controlled to be disconnected, and the started photovoltaic MPPT unit or the PFC unit is controlled to stop working, so as to complete the charging of the battery.

8. The power supply control method of the photovoltaic air conditioning system according to claim 4 or 5, characterized in that: In combination with the photovoltaic voltage of the photovoltaic module, the output voltage of the energy storage system, the remaining power of the energy storage system, and the bus voltage of the power supply bus, the first switch, the second switch, and the third switch are controlled to be turned on and off, and the photovoltaic MPPT unit and the PFC unit are controlled to be turned on and off to control at least one of the following: whether the photovoltaic air-conditioning system works, whether the photovoltaic module is powered, whether the mains is powered, and the charging or discharging operation of the energy storage system, and also includes: After the photovoltaic assembly is powered on, the first switch is controlled to be closed; after the mains power is powered on, the second switch is controlled to be closed; The target voltage of the photovoltaic MPPT unit and the target voltage of the PFC unit are set, the photovoltaic MPPT unit and the PFC unit are started, and the third switch is controlled to be disconnected so that the photovoltaic air-conditioning system works and the energy storage system does not work; at this time, a working mode in which only the photovoltaic air-conditioning system works is executed; wherein, in order to achieve the purpose of giving priority to the voltage of the photovoltaic module, the working target voltage of the photovoltaic MPPT unit is further made greater than the target voltage of the PFC unit.

9. The power supply control method of the photovoltaic air conditioning system according to claim 4 or 5, characterized in that: In combination with the photovoltaic voltage of the photovoltaic module, the output voltage of the energy storage system, the remaining power of the energy storage system, and the bus voltage of the power supply bus, the first switch, the second switch, and the third switch are controlled to be turned on and off, and the photovoltaic MPPT unit and the PFC unit are controlled to be turned on and off to control at least one of the following: whether the photovoltaic air-conditioning system works, whether the photovoltaic module is powered, whether the mains is powered, and the charging or discharging operation of the energy storage system, and also includes: After the photovoltaic assembly is powered on, the first switch is controlled to close, the target voltage is set to the output voltage of the energy storage system, the photovoltaic MPPT unit is started, and it is determined whether the absolute value of the difference between the output voltage of the energy storage system and the bus voltage of the power supply bus is less than a preset voltage error; If it is determined that the absolute value of the difference between the output voltage of the energy storage system and the bus voltage of the power supply bus is less than a preset voltage error, the third switch is controlled to close to start the charging mode of the energy storage system to charge the battery in the energy storage system; at this time, the photovoltaic assembly and the energy storage system simultaneously supply power to the photovoltaic air-conditioning system, and the photovoltaic air-conditioning system is operated and the energy storage system is charged. According to the power of the photovoltaic module and the power of the photovoltaic air-conditioning system, the maximum allowable charging current of the energy storage system is determined, and the charging operation of the energy storage system is controlled according to the maximum allowable charging current of the energy storage system until the charging of the battery is completed, and then the third switch is controlled to disconnect and switch to an operating mode in which only the photovoltaic air-conditioning system is operated.

10. The power supply control method of the photovoltaic air conditioning system according to claim 4 or 5, characterized in that: In combination with the photovoltaic voltage of the photovoltaic module, the output voltage of the energy storage system, the remaining power of the energy storage system, and the bus voltage of the power supply bus, the first switch, the second switch, and the third switch are controlled to be turned on and off, and the photovoltaic MPPT unit and the PFC unit are controlled to be turned on and off to control at least one of the following: whether the photovoltaic air-conditioning system works, whether the photovoltaic module is powered, whether the mains is powered, and the charging or discharging operation of the energy storage system, and also includes: After the photovoltaic assembly is powered on, the first switch is controlled to close, the target voltage is set to the output voltage of the energy storage system, the photovoltaic MPPT unit is started, and it is determined whether the absolute value of the difference between the output voltage of the energy storage system and the bus voltage of the power supply bus is less than a preset voltage error; If it is determined that the absolute value of the difference between the output voltage of the energy storage system and the bus voltage of the power supply bus is less than a preset voltage error, the third switch is controlled to close to start the discharge mode of the energy storage system to discharge the battery in the energy storage system; at this time, the photovoltaic assembly and the energy storage system simultaneously supply power to the photovoltaic air-conditioning system or the energy storage system alone supplies power to the photovoltaic air-conditioning system, and the photovoltaic air-conditioning system is operated and the energy storage system is discharged. According to the power of the photovoltaic module and the power of the photovoltaic air-conditioning system, the maximum allowable output current of the photovoltaic module is determined, and the discharge operation of the energy storage system is controlled according to the maximum allowable output current of the photovoltaic module, until the discharge current of the energy storage system is less than 0 and the power of the photovoltaic module is greater than the power of the photovoltaic air-conditioning system, and then the operation mode is switched to execute the photovoltaic air-conditioning system and charge the energy storage system.

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