Frequency conversion heat pump water heater and control method, device and storage medium thereof

Abstract

The present application discloses a variable frequency heat pump water heater and its control method, device and storage medium. The variable frequency heat pump water heater is powered by a grid-connected photovoltaic power generation system. The control method includes: obtaining the current operating state of the variable frequency heat pump water heater; determining the photovoltaic surplus power consumption scheme of the photovoltaic power generation system based on the current operating state; controlling the operation of the variable frequency heat pump water heater based on the photovoltaic surplus power consumption scheme; wherein the operating state of the variable frequency heat pump water heater includes at least: a first state in which heating is not started and a second state based on compressor heating; the types of photovoltaic surplus power consumption schemes include at least: a first scheme corresponding to the first state and a second scheme corresponding to the second state. In this way, the photovoltaic surplus power consumption scheme can be dynamically adjusted according to the current operating state of the variable frequency heat pump water heater, so that the clean energy based on photovoltaic power generation conversion can be maximized and utilized locally, thereby effectively improving the consumption effect of photovoltaic power.

Description

Technical Field

[0001] The present application relates to the technical field of water heaters, and in particular to a variable frequency heat pump water heater and a control method, device and storage medium thereof. Background Art

[0002] As a natural clean energy, solar energy is increasingly used. In related technologies, there is a method based on a grid-connected photovoltaic system to supply electricity generated by photovoltaic power generation to power loads, such as water heaters, thereby replacing traditional fossil energy with clean energy, which can reduce carbon emissions and help zero-carbon power generation.

[0003] However, the normal operation mode of the water heater is generally the default mode or the user-set mode, wherein the default mode is that the water heater is turned off when the current water temperature is greater than or equal to the default set water temperature, and is restarted when the current water temperature is less than or equal to the default set water temperature-temperature hysteresis; the user-set mode is that the water heater operates according to the target water temperature and / or operating time period pre-set by the user. The above-mentioned operation mode of the water heater does not take into account the consumption of photovoltaic power generation, which affects the recycling of clean energy. Summary of the invention

[0004] In view of this, the embodiments of the present application provide a variable frequency heat pump water heater and a control method, device and storage medium thereof, aiming to effectively improve the consumption effect of photovoltaic power.

[0005] The technical solution of the embodiment of the present application is implemented as follows:

[0006] In a first aspect, an embodiment of the present application provides a control method for a variable frequency heat pump water heater, wherein the variable frequency heat pump water heater is powered by a grid-connected photovoltaic power generation system, and the method comprises:

[0007] Obtaining the current operating status of the variable frequency heat pump water heater;

[0008] Based on the current operating state, determining a photovoltaic surplus power consumption scheme of the photovoltaic power generation system;

[0009] Based on the photovoltaic surplus power consumption scheme, controlling the operation of the variable frequency heat pump water heater;

[0010] Among them, the operating state of the variable frequency heat pump water heater includes at least: a first state where heating is not started and a second state based on compressor heating; the types of photovoltaic surplus power consumption schemes include at least: a first scheme corresponding to the first state and a second scheme corresponding to the second state.

[0011] In some implementation schemes, if the current operating state is the first state, the photovoltaic surplus power consumption scheme is the first scheme, and the control of the variable frequency heat pump water heater operation based on the photovoltaic surplus power consumption scheme includes:

[0012] Obtaining the state of charge (SOC) value of the energy storage unit in the photovoltaic power generation system, the online power value transmitted to the power grid by the photovoltaic power generation system, and the current water temperature value of the variable frequency heat pump water heater;

[0013] If it is determined that the SOC value is greater than or equal to the first set value, the online power value is greater than or equal to the first power value, and the current water temperature value is less than or equal to the second set value; then the set temperature value of the variable frequency heat pump water heater is adjusted to the current water temperature value plus the temperature hysteresis, and the compressor of the variable frequency heat pump water heater is controlled to start and run.

[0014] In some implementation schemes, if the current operating state is the second state, the photovoltaic surplus power consumption scheme is the second scheme, and the control of the variable frequency heat pump water heater operation based on the photovoltaic surplus power consumption scheme includes:

[0015] If it is determined that the running time of the compressor after starting reaches the first set time, the SOC value of the energy storage unit in the photovoltaic power generation system and the online power value transmitted by the photovoltaic power generation system to the power grid are obtained;

[0016] If it is determined that the SOC value is greater than or equal to the third set value and the online power value is greater than or equal to the second power value, the set temperature value of the variable frequency heat pump water heater is adjusted based on the current set temperature value and the set temperature adjustment value of the variable frequency heat pump water heater.

[0017] In some embodiments, adjusting the set temperature value of the variable frequency heat pump water heater based on the current set temperature value and the set temperature adjustment value of the variable frequency heat pump water heater includes:

[0018] If the current set temperature value is the initial set temperature value, then the set temperature value is updated to the sum of the initial set temperature value and the set temperature adjustment value;

[0019] If the current set temperature value is not one of the initial set temperature value and the set temperature upper limit value and the current set temperature value has been maintained for the second set time period, the smaller value of the sum of the current set temperature value plus the set temperature adjustment value and the set temperature upper limit value is updated as the set temperature value.

[0020] In some embodiments, if the variable frequency heat pump water heater has an electric heater for electric auxiliary heating and the electric heater is not turned on in the second state, the method further includes:

[0021] If the current set temperature value is the set temperature upper limit value and the current set temperature value has been maintained for the second set time period, the electric heater is turned on.

[0022] In some embodiments, if the variable frequency heat pump water heater has an electric heater for electric auxiliary heating, the operating state of the variable frequency heat pump water heater also includes: a third state in which only the electric heater is started for heating; the type of the photovoltaic surplus power consumption scheme also includes: a third scheme corresponding to the third state.

[0023] In some implementation schemes, if the current operating state is the third state, the photovoltaic surplus power consumption scheme is the third scheme, and the control of the variable frequency heat pump water heater operation based on the photovoltaic surplus power consumption scheme includes:

[0024] Obtaining the online power value transmitted to the power grid by the photovoltaic power generation system;

[0025] If it is determined that the online power value is greater than or equal to the third power value, the set temperature value of the variable frequency heat pump water heater is adjusted to a set temperature upper limit value.

[0026] In a second aspect, an embodiment of the present application provides a control device for a variable frequency heat pump water heater, wherein the variable frequency heat pump water heater is powered by a grid-connected photovoltaic power generation system, and the control device comprises:

[0027] An acquisition module, used to acquire the current operating status of the variable frequency heat pump water heater;

[0028] A determination module, used to determine a photovoltaic surplus power consumption scheme of the photovoltaic power generation system based on the current operating state;

[0029] A control module, used to control the operation of the variable frequency heat pump water heater based on the photovoltaic surplus power consumption scheme;

[0030] Among them, the operating state of the variable frequency heat pump water heater includes at least: a first state where heating is not started and a second state based on compressor heating; the types of photovoltaic surplus power consumption schemes include at least: a first scheme corresponding to the first state and a second scheme corresponding to the second state.

[0031] In a third aspect, an embodiment of the present application provides a variable frequency heat pump water heater, which is powered by a grid-connected photovoltaic power generation system, and comprises: a processor and a memory for storing a computer program that can be run on the processor, wherein the processor, when used to run the computer program, executes the steps of the method described in the first aspect of the embodiment of the present application.

[0032] In a fourth aspect, an embodiment of the present application provides a computer storage medium, on which a computer program is stored. When the computer program is executed by a processor, the steps of the method described in the first aspect of the embodiment of the present application are implemented.

[0033] The technical solution provided by the embodiment of the present application is that the variable frequency heat pump water heater is powered by a grid-connected photovoltaic power generation system, and the control method of the variable frequency heat pump water heater includes: obtaining the current operating state of the variable frequency heat pump water heater; based on the current operating state, determining the photovoltaic surplus power consumption plan of the photovoltaic power generation system; based on the photovoltaic surplus power consumption plan, controlling the operation of the variable frequency heat pump water heater; wherein, the operating state of the variable frequency heat pump water heater includes at least: a first state in which heating is not started and a second state based on compressor heating; the types of photovoltaic surplus power consumption plans include at least: a first plan corresponding to the first state and a second plan corresponding to the second state. In this way, the photovoltaic surplus power consumption plan can be dynamically adjusted according to the current operating state of the variable frequency heat pump water heater, so that the clean energy converted based on photovoltaic power generation can be maximized and utilized locally, thereby effectively improving the consumption effect of photovoltaic power. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 It is a structural schematic diagram of a heat pump water heater in the related art;

[0035] Figure 2 This is a schematic diagram of the structure in which a photovoltaic power generation system connected to the grid supplies power to a variable frequency heat pump water heater in an embodiment of the present application;

[0036] Figure 3 This is a flow chart of a control method of a variable frequency heat pump water heater according to an embodiment of the present application;

[0037] Figure 4 A flow chart of a control method for a variable frequency heat pump water heater in an application example of this application;

[0038] Figure 5 This is a schematic diagram of the structure of a control device for a variable frequency heat pump water heater according to an embodiment of the present application;

[0039] Figure 6 This is a schematic diagram of the structure of a variable frequency heat pump water heater according to an embodiment of the present application. DETAILED DESCRIPTION

[0040] The present application is further described in detail below in conjunction with the accompanying drawings and embodiments.

[0041] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art to which this application belongs. The terms used herein in the specification of this application are only for the purpose of describing specific embodiments and are not intended to limit this application.

[0042] Among the related technologies, new energy power generation, mainly photovoltaic, is developing rapidly. It is becoming increasingly popular to superimpose photovoltaic power supply (also known as superimposed light transformation) on the basis of AC power grid. Considering the volatility and intermittent characteristics of photovoltaic power generation energy, and the difficulty in storing energy, it will be wasted if it is not used in time. It is urgent to digest and absorb the energy of photovoltaic power generation (also known as photovoltaic power generation consumption). For example, the "self-generation and self-use" model can be adopted to use the energy generated by photovoltaic power generation to supply power to household power loads. However, the electricity demand of related household power loads often cannot match the volatility and intermittent characteristics of the above-mentioned photovoltaic power generation energy, which affects the photovoltaic power generation consumption effect.

[0043] Based on this, in an embodiment of the present application, a control method for a variable frequency heat pump water heater is provided, which aims to improve the photovoltaic power generation and consumption effect based on the optimized control of the variable frequency heat pump water heater.

[0044] Here, the variable frequency heat pump water heater (also known as the variable frequency air energy water heater) refers to a heat pump water heater based on variable frequency compression technology. The heat pump water heater can use air energy as a heat source, converting the heat contained in the air that cannot be directly used into usable high-level thermal energy, thereby achieving the purpose of heating water.

[0045] Simply put, the heat pump water heater works according to the "reverse Carnot" principle. Specifically, the "outdoor unit" acts as a heat exchanger to absorb heat from the outdoor air, heat the low-boiling-point working medium (refrigerant) and evaporate it. The refrigerant vapor is compressed and heated by the compressor before entering the water tank, releasing heat to the water therein and condensing it into liquid. It is then throttled, depressurized, and cooled before returning to the outdoor heat exchanger to enter the next cycle.

[0046] For example, Figure 1 As shown, the heat pump water heater includes: an evaporator arranged outdoors, a compressor and a water tank arranged indoors, the part of the refrigerant pipeline coiled around the outer wall of the water tank forms a condenser, and the refrigerant pipeline connects the evaporator and the compressor, and the refrigerant pipeline is provided with a throttling device (such as a capillary tube) between the condenser and the evaporator. Among them, the evaporator can absorb heat from the air and transfer it to the water tank through the refrigerant pipeline to heat the water in the water tank. Specifically, the refrigerant pipeline can release heat to the tap water in the water tank through the condenser coiled around the outer wall of the water tank, and the refrigerant after heat release condenses into liquid refrigerant, and the liquid refrigerant becomes a low-temperature and low-pressure two-phase fluid after the capillary is reduced in pressure. The low-temperature and low-pressure two-phase fluid absorbs heat from the outdoor air source at the evaporator, and the refrigerant after absorbing heat is introduced into the air inlet of the compressor. The high-temperature and high-pressure refrigerant compressed by the compressor is then transferred to the condenser to release heat, and the cycle is repeated to achieve the purpose of heating the tap water in the water tank.

[0047] Considering the temperature changes four degrees a year, people's demand for hot water is also different. For example, when the temperature is low, the temperature of hot water required for bathing will naturally be very high. When the temperature is high, the temperature of hot water required for bathing will naturally be relatively low. The fixed-frequency heat pump water heater can only operate at a single rated frequency, resulting in insufficient heating performance in winter and excessive heating in summer. The variable frequency heat pump water heater based on variable frequency compression technology can control the compressor speed based on the inverter, so as to better cope with environmental changes. Based on the variable frequency compression technology, the repeated switching of the compressor can be avoided, which is conducive to energy saving and consumption reduction.

[0048] It should be noted that the compressor operating frequency of the variable frequency heat pump water heater is related to the difference between the set temperature value and the current water temperature value of the variable frequency heat pump water heater. For example, the compressor operating frequency increases as the difference increases, and decreases as the difference decreases.

[0049] It should be noted that considering the stable reliability of heating, for example, when the external ambient temperature is too low, the heating effect based on the air source may be limited. The variable frequency heat pump water heater can also have an electric heater for electric auxiliary heating, and then the electric heater can be turned on for heating according to demand.

[0050] Before describing the control method of the variable frequency heat pump water heater according to the embodiment of the present application, the power supply structure of the variable frequency heat pump water heater according to the embodiment of the present application is described as an example.

[0051] In an application example, Figure 2 As shown, the variable frequency heat pump water heater 107 is powered by a grid-connected photovoltaic power generation system, which includes: at least one photovoltaic component 101, an energy storage unit 102, an inverter 103, a power sensor 104, a power grid 105 and a distribution cabinet 106.

[0052] Exemplarily, at least one photovoltaic module 101 is used to convert solar energy into direct current power output. For example, the at least one photovoltaic module 101 can be a photovoltaic panel that directly converts light energy into electrical energy by using the photovoltaic effect of the semiconductor interface. The at least one photovoltaic module 101 is connected to the energy storage unit 102 and the inverter 103. The alternating current converted by the inverter 103 is supplied to the power loads such as the variable frequency heat pump water heater 107 through the power distribution cabinet 106, and the inverter 103 can also transmit the photovoltaic surplus power to the power grid 105 through the power sensor 104, thereby forming a power supply scheme for transmitting the surplus power to the power grid, that is, forming a photovoltaic power generation grid-connected mode of self-generation and self-use, and the surplus power is connected to the grid.

[0053] Here, the power sensor 104 (also called a bidirectional meter) is used to detect the online power transmitted to the grid 105 by the photovoltaic surplus power and the power taken from the grid 105. The power distribution cabinet 106 is used to supply power to the power load. For example, an AC-AC (alternating current to direct current) conversion circuit and / or an AC-DC (alternating current to direct current) conversion circuit may be provided in the power distribution cabinet 106, which is not limited in the embodiment of the present application.

[0054] Exemplarily, the direct current outputted by at least one photovoltaic module 101 may also be converted by a DC-DC (direct current to direct current) conversion circuit and then connected to the energy storage unit 102 and the inverter 103. The DC-DC conversion circuit is used to convert the direct current outputted by at least one photovoltaic module 101 to a target direct current voltage to charge the energy storage unit 102 and / or input it to the inverter 103.

[0055] Exemplarily, the energy storage unit 102 may include: at least one battery or battery cluster and a battery management system (BMS). At least one battery or battery cluster is connected in series or in parallel to form a battery array. The number of battery clusters can be flexibly increased or decreased according to the demand for backup power or the set backup power duration. The battery management system can control and adjust the output power of the battery cluster. Due to the different numbers of batteries or battery clusters in the energy storage unit 102, the corresponding backup power or backup power duration of the energy storage unit 102 is also different.

[0056] The present application provides a control method for a variable frequency heat pump water heater. Figure 2 The control method can be operated by a variable frequency heat pump water heater or by a control device for controlling a variable frequency heat pump water heater. Figure 3 As shown, the control method includes:

[0057] Step 301, obtaining the current operating status of the variable frequency heat pump water heater.

[0058] Step 302: Determine a photovoltaic surplus power consumption plan for the photovoltaic power generation system based on the current operating state.

[0059] Step 303: Based on the photovoltaic surplus power consumption plan, control the operation of the variable frequency heat pump water heater.

[0060] Here, the operating state of the variable frequency heat pump water heater includes at least: a first state in which heating is not started and a second state based on compressor heating; the types of photovoltaic surplus power consumption schemes include at least: a first scheme corresponding to the first state and a second scheme corresponding to the second state.

[0061] It can be understood that the embodiment of the present application can dynamically adjust the photovoltaic surplus power consumption plan according to the current operating status of the variable frequency heat pump water heater, so that the clean energy converted based on photovoltaic power generation can be maximized for local utilization, thereby effectively improving the photovoltaic power consumption effect.

[0062] Specifically, since the operating frequency of the compressor of the variable frequency heat pump water heater increases during the startup phase, photovoltaic power generation may turn from surplus to deficit. The embodiment of the present application adopts different photovoltaic surplus power consumption schemes for the aforementioned first state and second state, which can maximize the utilization of hot water energy storage in the variable frequency heat pump water heater for photovoltaic power generation consumption.

[0063] In some embodiments, if the current operating state is the first state, the photovoltaic surplus power consumption scheme is the first scheme, and the control of the variable frequency heat pump water heater operation based on the photovoltaic surplus power consumption scheme includes:

[0064] Obtaining the SOC value of the energy storage unit in the photovoltaic power generation system, the online power value transmitted to the power grid by the photovoltaic power generation system, and the current water temperature value of the variable frequency heat pump water heater;

[0065] If it is determined that the SOC value is greater than or equal to the first set value, the online power value is greater than or equal to the first power value, and the current water temperature value is less than or equal to the second set value; then the set temperature value of the variable frequency heat pump water heater is adjusted to the current water temperature value plus the temperature hysteresis, and the compressor of the variable frequency heat pump water heater is controlled to start and run.

[0066] It is understandable that the SOC value of the energy storage unit is used to reflect the remaining capacity of the energy storage unit, and its numerical value is defined as the ratio of the remaining capacity to the battery capacity, usually expressed as a percentage. When SOC = 0, it means that the battery is fully discharged, and when SOC = 1, it means that the battery is fully charged. Here, the SOC value of the energy storage unit can be generated by the battery management system based on certain external characteristics of the battery. For example, based on the internal resistance, open circuit voltage, temperature, current and other related parameters of the battery, the state of charge can be monitored using a formula.

[0067] Here, the online power value transmitted to the power grid by the photovoltaic power generation system can be detected by the aforementioned power sensor, which represents the online power of the photovoltaic surplus electricity generated by the photovoltaic power generation system.

[0068] Here, the first setting value, the first power value, and the second setting value can be pre-set according to the demand for photovoltaic power generation and consumption, and the temperature hysteresis can be set based on the water temperature fluctuation control demand of the water heater. For example, in an application example, the first setting value is 80%, the first power value is the rated power value of the compressor of the variable frequency heat pump water heater, and the second setting value is the set temperature upper limit value minus the temperature hysteresis.

[0069] It can be understood that when the variable frequency heat pump water heater is in the first state, the operation of the variable frequency heat pump water heater is controlled based on the first scheme. When there is a surplus of photovoltaic power generation, the surplus photovoltaic power can be used to start the compressor, and the energy required to heat the water in the variable frequency heat pump water heater can be used to realize the absorption of photovoltaic power generation.

[0070] In some embodiments, if the current operating state is the second state, the photovoltaic surplus power consumption scheme is the second scheme, and the control of the variable frequency heat pump water heater operation based on the photovoltaic surplus power consumption scheme includes:

[0071] If it is determined that the running time of the compressor after starting reaches the first set time, the SOC value of the energy storage unit in the photovoltaic power generation system and the online power value transmitted by the photovoltaic power generation system to the power grid are obtained;

[0072] If it is determined that the SOC value is greater than or equal to the third set value and the online power value is greater than or equal to the second power value, the set temperature value of the variable frequency heat pump water heater is adjusted based on the current set temperature value and the set temperature adjustment value of the variable frequency heat pump water heater.

[0073] Here, considering that the variable frequency heat pump water heater has an increased compressor operating frequency during the startup phase, which may cause the photovoltaic power generation to turn from surplus to deficit, in order to avoid misjudgment of the photovoltaic surplus power consumption strategy caused by the increase in compressor operating power during the startup phase, the first set time can be pre-set so that after the compressor runs stably, it can be judged whether the photovoltaic power generation is surplus. Exemplarily, the first set time can be 15 minutes.

[0074] Here, the third set value and the second power value can be pre-set according to the demand for photovoltaic power generation and consumption. The set temperature value is used as the target temperature for water heating of the variable frequency heat pump water heater for heating control. When setting the thermostat value as the photovoltaic power generation surplus, the set temperature value is gradually increased based on the set step size, which can effectively avoid the photovoltaic power generation from surplus to shortage due to excessive increase in the set temperature value, which is conducive to the continuous and reliable realization of photovoltaic power generation and consumption. For example, in an application example, the third set value is 80%, the second power value is 500W (watts), and the set thermostat value is 5°C.

[0075] In some embodiments, adjusting the set temperature value of the variable frequency heat pump water heater based on the current set temperature value and the set temperature adjustment value of the variable frequency heat pump water heater includes:

[0076] If the current set temperature value is the initial set temperature value, then the set temperature value is updated to the sum of the initial set temperature value and the set temperature adjustment value;

[0077] If the current set temperature value is not one of the initial set temperature value and the set temperature upper limit value and the current set temperature value has been maintained for the second set time period, the smaller value of the sum of the current set temperature value plus the set temperature adjustment value and the set temperature upper limit value is updated as the set temperature value.

[0078] For example, the initial set temperature value may be 40°C, and the set temperature upper limit value may be 70°C. It is understood that those skilled in the art may reasonably set the above initial set temperature value and / or the set temperature upper limit value according to the demand for hot water use. For example, the second set time length may be 5 minutes, which may be understood as the interval time length for gradually increasing the set temperature value, and those skilled in the art may reasonably set it based on demand.

[0079] In some embodiments, if the variable frequency heat pump water heater has an electric heater for electric auxiliary heating and the electric heater is not turned on in the second state, the method further includes:

[0080] If the current set temperature value is the set temperature upper limit value and the current set temperature value has been maintained for the second set time period, the electric heater is turned on.

[0081] It is understandable that in the second state, if it is determined that the photovoltaic power generation is in surplus, in addition to gradually increasing the set temperature value, the electric heater can also be used for rapid heat storage. Specifically, if the variable frequency heat pump water heater is in the second state, after determining that the compressor starts running for the first set time, the SOC value obtained is greater than or equal to the third set value and the online power value is greater than or equal to the second power value, it is determined that the photovoltaic power generation is in surplus, and the current set temperature value is the set temperature upper limit value and the current set temperature value has been maintained for the second set time, then the electric heater is turned on when it is not turned on, and then the photovoltaic surplus power can be used to power the electric heater, and then the photovoltaic power generation can be quickly absorbed by heating water.

[0082] In some embodiments, if the variable frequency heat pump water heater has an electric heater for electric auxiliary heating, the operating state of the variable frequency heat pump water heater also includes: a third state in which only the electric heater is started for heating; the type of the photovoltaic surplus power consumption scheme also includes: a third scheme corresponding to the third state.

[0083] In some embodiments, if the current operating state is the third state, the photovoltaic surplus power consumption scheme is the third scheme, and the control of the variable frequency heat pump water heater operation based on the photovoltaic surplus power consumption scheme includes:

[0084] Obtaining the online power value transmitted to the power grid by the photovoltaic power generation system;

[0085] If it is determined that the online power value is greater than or equal to the third power value, the set temperature value of the variable frequency heat pump water heater is adjusted to a set temperature upper limit value.

[0086] It can be understood that in the third state, if the online power value is greater than or equal to the third power value, when it is determined that the photovoltaic power generation is in surplus, the set temperature value of the variable frequency heat pump water heater can be adjusted to the set temperature upper limit value, and then the photovoltaic surplus power can be used to power the electric heater, and the photovoltaic power generation can be maximized by heating hot water.

[0087] It should be noted that the operating state of the variable frequency heat pump water heater can be switched based on the set heating strategy or based on the user's control instructions. For example, the variable frequency heat pump water heater can operate in the above-mentioned second state or third state during the heating operation period specified by the user, and operate in the above-mentioned first state during the rest of the time period. The embodiments of the present application are not limited to this.

[0088] The control method of the variable frequency heat pump water heater in the embodiment of the present application is illustrated below with reference to an application example.

[0089] In this application example, the control method of the variable frequency heat pump water heater includes: selecting a photovoltaic surplus power consumption strategy (ie, the aforementioned photovoltaic surplus power consumption scheme) according to the current operating state of the variable frequency heat pump water heater.

[0090] Here, the operating states of the variable frequency heat pump water heater include the following four states: state a, state b, state c and state d, wherein state a indicates that both the compressor and the electric heating are off (corresponding to the aforementioned first state), state b indicates that only the electric heating is on (corresponding to the aforementioned third state), state c indicates that only the compressor is on, and state d indicates that both the compressor and the electric heating are on.

[0091] Combine the following Figure 4 The photovoltaic surplus power consumption strategy corresponding to each operating state in this application example is illustrated as follows:

[0092] If the current operating state is state a, determine whether the battery SOC value is ≥80% and the online power value is ≥P1 and T≤70℃-dT_ON, where P1 is the rated power of the compressor (i.e. the first power value mentioned above), 70℃ is the set temperature upper limit, and dT_ON is the temperature hysteresis. If so, the compressor can be started and operated using the photovoltaic surplus power, and the set temperature value Ts=T+dT_ON, where T is the current water temperature; if not, operate as usual, i.e. maintain the current operating state.

[0093] If the current operating state is state b, determine whether the online power value is ≥ P2, where P2 is the aforementioned third power value and can be 100W. If so, set the temperature value Ts=70°C; if not, run as usual.

[0094] If the current operating state is state c or state d, wait until the compressor has been running for 15 minutes to determine whether the photovoltaic power generation is surplus. If the battery SOC value is ≥80% and the online power value is ≥P3, where P3 is the second power value mentioned above, which can be 500W, if so, the set temperature value can be increased; if not, it will run as usual.

[0095] Among them, the specific strategies for increasing the set temperature value are as follows:

[0096] If the current set temperature value is Ts_0, then set the set temperature value Ts = Ts_0 + 5°C, where Ts_0 is the initial set temperature value and 5°C is the step length for gradually increasing the water temperature;

[0097] If the current set temperature is 70°C and has been maintained for 5 minutes, the electric heating will be turned on in state c, and will not be activated in state d;

[0098] If Ts≠70°C and Ts≠Ts_0, and the current set temperature value has been maintained unchanged for 5 minutes, then Ts=min(Ts+5°C, 70°C).

[0099] It can be understood that the control method of this application example has the following beneficial effects:

[0100] 1) Wait until the compressor has been running for 15 minutes before starting to judge whether photovoltaic power generation is surplus, which can effectively avoid misjudgment caused by the increase of compressor power during the startup phase. After the compressor runs stably, it can be judged whether photovoltaic power generation is surplus, so that the surplus photovoltaic power can be effectively consumed;

[0101] 2) When the photovoltaic power generation is in surplus, the water temperature is gradually increased. The set temperature value is gradually increased based on the set step size, which can effectively avoid the excessive increase in the set temperature value, causing the photovoltaic power generation to turn from surplus to shortage, and is conducive to the continuous and reliable realization of the photovoltaic surplus power consumption;

[0102] 3) When the set temperature is the upper limit of 70°C, the electric heating is not turned on, and there is a photovoltaic surplus, the photovoltaic surplus power can be used to turn on the electric heating to quickly heat the water, and then the heated water can be used to quickly consume the photovoltaic surplus power.

[0103] In order to implement the method of the embodiment of the present application, the embodiment of the present application also provides a control device of a variable frequency heat pump water heater, which corresponds to the control method of the variable frequency heat pump water heater mentioned above, and each step in the embodiment of the control method of the variable frequency heat pump water heater mentioned above is also fully applicable to the control device embodiment of the variable frequency heat pump water heater.

[0104] like Figure 5As shown, the control device of the variable frequency heat pump water heater includes: an acquisition module 501, a determination module 502 and a control module 503. The acquisition module 501 is used to acquire the current operating state of the variable frequency heat pump water heater; the determination module 502 is used to determine the photovoltaic surplus power consumption scheme of the photovoltaic power generation system based on the current operating state; the control module 503 is used to control the operation of the variable frequency heat pump water heater based on the photovoltaic surplus power consumption scheme; wherein the operating state of the variable frequency heat pump water heater includes at least: a first state in which heating is not started and a second state based on compressor heating; the types of the photovoltaic surplus power consumption scheme include at least: a first scheme corresponding to the first state and a second scheme corresponding to the second state.

[0105] In some embodiments, if the current operating state is the first state, the photovoltaic surplus power consumption scheme is the first scheme, and the control module 503 is specifically used to:

[0106] Obtaining the SOC value of the energy storage unit in the photovoltaic power generation system, the online power value transmitted to the power grid by the photovoltaic power generation system, and the current water temperature value of the variable frequency heat pump water heater;

[0107] If it is determined that the SOC value is greater than or equal to the first set value, the online power value is greater than or equal to the first power value, and the current water temperature value is less than or equal to the second set value; then the set temperature value of the variable frequency heat pump water heater is adjusted to the current water temperature value plus the temperature hysteresis, and the compressor of the variable frequency heat pump water heater is controlled to start and run.

[0108] In some embodiments, if the current operating state is the second state, the photovoltaic surplus power consumption scheme is the second scheme, and the control module 503 is specifically used to:

[0109] If it is determined that the running time of the compressor after starting reaches the first set time, the SOC value of the energy storage unit in the photovoltaic power generation system and the online power value transmitted by the photovoltaic power generation system to the power grid are obtained;

[0110] If it is determined that the SOC value is greater than or equal to the third set value and the online power value is greater than or equal to the second power value, the set temperature value of the variable frequency heat pump water heater is adjusted based on the current set temperature value and the set temperature adjustment value of the variable frequency heat pump water heater.

[0111] In some embodiments, the control module 503 adjusts the set temperature value of the variable frequency heat pump water heater based on the current set temperature value and the set temperature adjustment value of the variable frequency heat pump water heater, including:

[0112] If the current set temperature value is the initial set temperature value, then the set temperature value is updated to the sum of the initial set temperature value and the set temperature adjustment value;

[0113] If the current set temperature value is not one of the initial set temperature value and the set temperature upper limit value and the current set temperature value has been maintained for the second set time period, the smaller value of the sum of the current set temperature value plus the set temperature adjustment value and the set temperature upper limit value is updated as the set temperature value.

[0114] In some embodiments, if the variable frequency heat pump water heater has an electric heater for electric auxiliary heating and the electric heater is not turned on in the second state, the control module 503 is further used to:

[0115] If the current set temperature value is the set temperature upper limit value and the current set temperature value has been maintained for the second set time period, the electric heater is turned on.

[0116] In some embodiments, if the variable frequency heat pump water heater has an electric heater for electric auxiliary heating, the operating state of the variable frequency heat pump water heater also includes: a third state in which only the electric heater is started for heating; the type of the photovoltaic surplus power consumption scheme also includes: a third scheme corresponding to the third state.

[0117] In some embodiments, if the current operating state is the third state, the photovoltaic surplus power consumption scheme is the third scheme, and the control module 503 is specifically used to:

[0118] Obtaining the online power value transmitted to the power grid by the photovoltaic power generation system;

[0119] If it is determined that the online power value is greater than or equal to the third power value, the set temperature value of the variable frequency heat pump water heater is adjusted to a set temperature upper limit value.

[0120] In actual application, the acquisition module 501, the determination module 502 and the control module 503 can be implemented by a processor of the variable frequency heat pump water heater. Of course, the processor needs to run the computer program in the memory to realize its function.

[0121] It should be noted that: the control device of the variable frequency heat pump water heater provided in the above embodiment only uses the division of the above program modules as an example when controlling the variable frequency heat pump water heater. In actual applications, the above processing can be assigned to different program modules as needed, that is, the internal structure of the device is divided into different program modules to complete all or part of the processing described above. In addition, the control device of the variable frequency heat pump water heater provided in the above embodiment and the control method embodiment of the variable frequency heat pump water heater belong to the same concept. The specific implementation process is detailed in the method embodiment and will not be repeated here.

[0122] Based on the hardware implementation of the above program modules, and in order to implement the method of the embodiment of the present application, the embodiment of the present application also provides a variable frequency heat pump water heater. Figure 6 Only the exemplary structure of the variable frequency heat pump water heater is shown, not all structures, and can be implemented as needed. Figure 6 Partial or complete structure shown.

[0123] like Figure 6 As shown, the variable frequency heat pump water heater 600 provided in the embodiment of the present application includes: at least one processor 601, a memory 602 and a user interface 603. The various components in the variable frequency heat pump water heater 600 are coupled together through a bus system 604. It can be understood that the bus system 604 is used to realize the connection and communication between these components. In addition to the data bus, the bus system 604 also includes a power bus, a control bus and a status signal bus. However, for the sake of clarity, in Figure 6 Various buses are labeled as bus system 604 .

[0124] The user interface 603 may include a trackball, a click wheel, keys, buttons, a touch pad or a touch screen.

[0125] The memory 602 in the embodiment of the present application is used to store various types of data to support the operation of the variable frequency heat pump water heater. Examples of such data include: any computer program used to operate on the variable frequency heat pump water heater.

[0126] The control method of the variable frequency heat pump water heater disclosed in the embodiment of the present application can be applied to the processor 601, or implemented by the processor 601. The processor 601 may be an integrated circuit chip with signal processing capabilities. In the implementation process, each step of the control method of the variable frequency heat pump water heater can be completed by the hardware integrated logic circuit or software instructions in the processor 601. The above-mentioned processor 601 can be a general processor, a digital signal processor (DSP, Digital Signal Processor), or other programmable logic devices, discrete gates or transistor logic devices, discrete hardware components, etc. The processor 601 can implement or execute the various methods, steps and logic block diagrams disclosed in the embodiment of the present application. The general processor can be a microprocessor or any conventional processor, etc. In combination with the steps of the method disclosed in the embodiment of the present application, it can be directly embodied as a hardware decoding processor to execute, or it can be executed by a combination of hardware and software modules in the decoding processor. The software module can be located in a storage medium, which is located in the memory 602. The processor 601 reads the information in the memory 602 and completes the steps of the control method of the variable frequency heat pump water heater provided in the embodiment of the present application in combination with its hardware.

[0127] In an exemplary embodiment, the variable frequency heat pump water heater can be implemented by one or more application specific integrated circuits (ASIC), DSP, programmable logic device (PLD), complex programmable logic device (CPLD), field programmable gate array (FPGA), general processor, controller, microcontroller (MCU), microprocessor, or other electronic components to execute the aforementioned method.

[0128] It can be understood that the memory 602 can be a volatile memory or a non-volatile memory, and can also include both volatile and non-volatile memories. Among them, the non-volatile memory can be a read-only memory (ROM), a programmable read-only memory (PROM), an erasable programmable read-only memory (EPROM), an electrically erasable programmable read-only memory (EEPROM), a magnetic random access memory (FRAM), a flash memory, a magnetic surface memory, an optical disk, or a compact disc read-only memory (CD-ROM); the magnetic surface memory can be a disk memory or a tape memory. The volatile memory can be a random access memory (RAM), which is used as an external cache. By way of example and not limitation, many forms of RAM are available, such as static random access memory (SRAM), synchronous static random access memory (SSRAM), dynamic random access memory (DRAM), synchronous dynamic random access memory (SDRAM), double data rate synchronous dynamic random access memory (DDRSDRAM), enhanced synchronous dynamic random access memory (ESDRAM), synchronous link dynamic random access memory (SLDRAM, SyncLink Dynamic Random Access Memory), and direct RAM bus random access memory (DRRAM, Direct Rambus Random Access Memory).The memories described in the embodiments of the present application are intended to include, but are not limited to, these and any other suitable types of memories.

[0129] In an exemplary embodiment, the present application also provides a computer storage medium, which can be a computer-readable storage medium, for example, a memory 602 storing a computer program, and the computer program can be executed by a processor 601 of a variable frequency heat pump water heater to complete the steps described in the method of the present application embodiment. The computer-readable storage medium can be a memory such as a ROM, a PROM, an EPROM, an EEPROM, a Flash Memory, a magnetic surface memory, an optical disk, or a CD-ROM.

[0130] It should be noted that: "first", "second", etc. are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence.

[0131] In addition, the technical solutions described in the embodiments of the present application can be combined arbitrarily without conflict.

[0132] The above is only a specific implementation of the present application, but the protection scope of the present application is not limited thereto. Any technician familiar with the technical field can easily think of changes or substitutions within the technical scope disclosed in the present application, which should be included in the protection scope of the present application. Therefore, the protection scope of the present application should be based on the protection scope of the claims.

Claims

1. A control method for a variable frequency heat pump water heater, characterized in that: The variable frequency heat pump water heater is powered by a grid-connected photovoltaic power generation system, and the method comprises: Obtaining the current operating status of the variable frequency heat pump water heater; Based on the current operating state, determining a photovoltaic surplus power consumption scheme of the photovoltaic power generation system; Based on the photovoltaic surplus power consumption scheme, controlling the operation of the variable frequency heat pump water heater; The operating state of the variable frequency heat pump water heater includes at least: a first state in which heating is not started and a second state in which heating is based on a compressor; the types of the photovoltaic surplus power consumption scheme include at least: a first scheme corresponding to the first state and a second scheme corresponding to the second state; If the current operating state is the first state, the photovoltaic surplus power consumption scheme is the first scheme, and the control of the variable frequency heat pump water heater to operate based on the photovoltaic surplus power consumption scheme includes: Obtaining the state of charge (SOC) value of the energy storage unit in the photovoltaic power generation system, the online power value transmitted to the power grid by the photovoltaic power generation system, and the current water temperature value of the variable frequency heat pump water heater; If it is determined that the SOC value is greater than or equal to the first set value, the online power value is greater than or equal to the first power value, and the current water temperature value is less than or equal to the second set value; then the set temperature value of the variable frequency heat pump water heater is adjusted to the current water temperature value plus the temperature hysteresis, and the compressor of the variable frequency heat pump water heater is controlled to start running; If the current operating state is the second state, the photovoltaic surplus power consumption scheme is the second scheme, and the control of the variable frequency heat pump water heater to operate based on the photovoltaic surplus power consumption scheme includes: If it is determined that the running time of the compressor after starting reaches the first set time, the SOC value of the energy storage unit in the photovoltaic power generation system and the online power value transmitted by the photovoltaic power generation system to the power grid are obtained; If it is determined that the SOC value is greater than or equal to the third set value and the online power value is greater than or equal to the second power value, the set temperature value of the variable frequency heat pump water heater is adjusted based on the current set temperature value and the set temperature adjustment value of the variable frequency heat pump water heater.

2. The method according to claim 1, characterized in that: The step of adjusting the set temperature value of the variable frequency heat pump water heater based on the current set temperature value and the set temperature adjustment value of the variable frequency heat pump water heater comprises: If the current set temperature value is the initial set temperature value, then the set temperature value is updated to the sum of the initial set temperature value and the set temperature adjustment value; If the current set temperature value is not one of the initial set temperature value and the set temperature upper limit value and the current set temperature value has been maintained for the second set time period, the smaller value of the sum of the current set temperature value plus the set temperature adjustment value and the set temperature upper limit value is updated as the set temperature value.

3. The method according to claim 2, characterized in that If the variable frequency heat pump water heater has an electric heater for electric auxiliary heating and the electric heater is not turned on in the second state, the method further includes: If the current set temperature value is the set temperature upper limit value and the current set temperature value has been maintained for the second set time period, the electric heater is turned on.

4. The method according to claim 1, characterized in that If the variable frequency heat pump water heater has an electric heater for electric auxiliary heating, the operating state of the variable frequency heat pump water heater also includes: a third state in which only the electric heater is started for heating; the type of the photovoltaic surplus power consumption scheme also includes: a third scheme corresponding to the third state.

5. The method according to claim 4, characterized in that If the current operating state is the third state, the photovoltaic surplus power consumption scheme is the third scheme, and the control of the variable frequency heat pump water heater to operate based on the photovoltaic surplus power consumption scheme includes: Obtaining the online power value transmitted to the power grid by the photovoltaic power generation system; If it is determined that the online power value is greater than or equal to the third power value, the set temperature value of the variable frequency heat pump water heater is adjusted to a set temperature upper limit value.

6. A control device for a variable frequency heat pump water heater, characterized in that: The variable frequency heat pump water heater is powered by a grid-connected photovoltaic power generation system, and the control device includes: An acquisition module, used to acquire the current operating status of the variable frequency heat pump water heater; A determination module, used to determine a photovoltaic surplus power consumption scheme of the photovoltaic power generation system based on the current operating state; A control module, used to control the operation of the variable frequency heat pump water heater based on the photovoltaic surplus power consumption scheme; The operating state of the variable frequency heat pump water heater includes at least: a first state in which heating is not started and a second state in which heating is based on a compressor; the types of the photovoltaic surplus power consumption scheme include at least: a first scheme corresponding to the first state and a second scheme corresponding to the second state; The control module is specifically used for: If the current operating state is the first state, the photovoltaic surplus power consumption plan is the first plan; obtain the SOC value of the energy storage unit in the photovoltaic power generation system, the online power value transmitted to the power grid by the photovoltaic power generation system, and the current water temperature value of the variable frequency heat pump water heater; If it is determined that the SOC value is greater than or equal to the first set value, the online power value is greater than or equal to the first power value, and the current water temperature value is less than or equal to the second set value; then the set temperature value of the variable frequency heat pump water heater is adjusted to the current water temperature value plus the temperature hysteresis, and the compressor of the variable frequency heat pump water heater is controlled to start running; If the current operating state is the second state, the photovoltaic surplus power consumption plan is the second plan; if it is determined that the operating time after the compressor is started reaches the first set time, the SOC value of the energy storage unit in the photovoltaic power generation system and the online power value transmitted to the power grid by the photovoltaic power generation system are obtained; if it is determined that the SOC value is greater than or equal to the third set value and the online power value is greater than or equal to the second power value, the set temperature value of the variable frequency heat pump water heater is adjusted based on the current set temperature value and set temperature adjustment value of the variable frequency heat pump water heater; the first set time represents the time required for the compressor to start up and run stably.

7. A variable frequency heat pump water heater, characterized in that: The variable frequency heat pump water heater is powered by a grid-connected photovoltaic power generation system, and the variable frequency heat pump water heater comprises: a processor and a memory for storing a computer program that can be run on the processor, wherein: The processor is used to execute the steps of the method according to any one of claims 1 to 5 when running a computer program.

8. A computer storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the steps of the method according to any one of claims 1 to 5 are implemented.

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