A photovoltaic heat pump power supply system, heat pump system and control method

Abstract

The present application discloses a power supply system, a heat pump system and a control method for a photovoltaic heat pump; the power supply system includes: a controller, a first power conversion circuit, a second power conversion circuit and an inverter; the input end of the first power conversion circuit is used to connect to a photovoltaic array; the output end of the first power conversion circuit is connected to a DC bus; the DC end of the inverter is connected to the DC bus; the AC end of the inverter is used to connect to a compressor of a heat pump; the DC end of the second power conversion circuit is connected to the DC bus; the AC end of the second power conversion circuit is used to connect to a power grid; the controller is used to control the first power conversion circuit to reduce the output power of the photovoltaic array when the difference between the output power of the first power conversion circuit and the input power of the DC end of the second power conversion circuit is greater than the working power of the compressor. It can reduce the occurrence of overvoltage faults in the power supply system and improve the safety and stability of the power supply system of the heat pump.

Description

Technical Field

[0001] The present application relates to the field of new energy technology, and in particular to a photovoltaic heat pump power supply system, a heat pump system and a control method. Background Art

[0002] Heat pump systems are gaining more and more attention. Taking air source heat pumps as an example, heat pump systems include compressors and power supply systems. The power supply system supplies power to the compressor, which drives the air to generate heat exchange for heating. Compared with fossil fuel heating, heat pump systems generate less carbon dioxide and are energy-saving and environmentally friendly.

[0003] With the gradual development of photovoltaic power generation technology, heat pump systems have begun to use the power grid in conjunction with photovoltaic arrays for power supply. However, since the power generation power of photovoltaic arrays is affected by solar irradiance, it has strong volatility and randomness; when there is a power limit on the power grid, the power of the photovoltaic array in the power supply system exceeds the power of the compressor, resulting in the inability to absorb the excess energy, causing the heat pump power supply system to be over-voltage, affecting the safe and stable operation of the compressor. Summary of the invention

[0004] In view of this, the present application provides a power supply system, a heat pump system and a control method of a photovoltaic heat pump, which can reduce overvoltage failures in the power supply system and improve the safety and stability of the power supply system of the heat pump.

[0005] To solve the above problems, the technical solutions provided by this application are as follows:

[0006] In a first aspect, the present application provides a power supply system for a photovoltaic heat pump, comprising: a controller, a first power conversion circuit, a second power conversion circuit, and an inverter;

[0007] The input end of the first power conversion circuit is used to connect to the photovoltaic array; the output end of the first power conversion circuit is connected to the DC bus; the DC end of the inverter is connected to the DC bus; the AC end of the inverter is used to connect to the compressor of the heat pump;

[0008] The DC end of the second power conversion circuit is connected to the DC bus; the AC end of the second power conversion circuit is used to connect to the power grid;

[0009] The controller is used to control the first power conversion circuit to reduce the output power of the photovoltaic array when the difference between the output power of the first power conversion circuit and the DC end input power of the second power conversion circuit is greater than the working power of the compressor.

[0010] Preferably, the controller is specifically configured to reduce the output power of the photovoltaic array by controlling the power devices of the first power conversion circuit according to the output voltage of the first power conversion circuit and the input voltage of the first power conversion circuit.

[0011] Preferably, the controller is specifically used to reduce the output power of the photovoltaic array by controlling the power devices of the first power conversion circuit according to the output voltage of the first power conversion circuit, the preset voltage upper limit value, the maximum power tracking voltage and the input voltage of the first power conversion circuit.

[0012] Preferably, the controller is specifically used to reduce the output power of the photovoltaic array by controlling the power devices of the first power conversion circuit according to the output voltage of the first power conversion circuit, the preset voltage upper limit value, the maximum power tracking voltage, the input current of the first power conversion circuit and the input voltage of the first power conversion circuit.

[0013] Preferably, the controller is specifically used to obtain a first process instruction and a second process instruction according to a difference between an output voltage of the first power conversion circuit and a preset voltage upper limit value, and a difference between an input voltage of the first power conversion circuit and a maximum power tracking voltage; take the smaller of the first process instruction and the second process instruction as a third process instruction; and obtain a pulse width modulation drive signal of each power device in the first power conversion circuit according to the third process instruction and the input current to reduce the output power of the photovoltaic array.

[0014] Preferably, the controller is also used to reduce the operating power of the compressor when the sum of the output power of the first power conversion circuit and the output power of the second power conversion circuit is less than the required power of the compressor, so as to maintain the energy balance of the power supply system.

[0015] A second aspect of the present application provides a photovoltaic heat pump system, comprising: a compressor and the photovoltaic heat pump power supply system described above;

[0016] The first end of the power system is used to connect to the photovoltaic array;

[0017] The second end of the power supply system is used to connect to the power grid;

[0018] The third end of the power supply system is connected to the compressor for supplying power to the compressor.

[0019] A third aspect of the present application provides a control method for a power supply system of a photovoltaic heat pump, the power supply system comprising: a first power conversion circuit, a second power conversion circuit and an inverter;

[0020] The input end of the first power conversion circuit is used to connect to the photovoltaic array; the output end of the first power conversion circuit is connected to the DC bus; the DC end of the inverter is connected to the DC bus; the AC end of the inverter is used to connect to the compressor of the heat pump;

[0021] The method includes:

[0022] When the difference between the output power of the first power conversion circuit and the DC end input power of the second power conversion circuit is greater than the working power of the compressor, the first power conversion circuit is controlled to reduce the output power of the photovoltaic array.

[0023] Preferably, the method further comprises: judging, by the output voltage of the first power conversion circuit, that the difference between the output power of the first power conversion circuit and the input power of the second power conversion circuit is greater than the working power of the compressor;

[0024] Controlling the first power conversion circuit to reduce the output power of the photovoltaic array specifically includes:

[0025] According to the output voltage of the first power conversion circuit and the input voltage of the first power conversion circuit, the output power of the photovoltaic array is reduced by controlling the power devices of the first power conversion circuit.

[0026] Preferably, controlling the first power conversion circuit to reduce the output power of the photovoltaic array specifically includes:

[0027] The output power of the photovoltaic array is reduced by controlling the power devices of the first power conversion circuit according to the output voltage of the first power conversion circuit, the preset voltage upper limit value, the maximum power tracking voltage and the input voltage of the first power conversion circuit.

[0028] Preferably, controlling the first power conversion circuit to reduce the output power of the photovoltaic array specifically includes:

[0029] The output power of the photovoltaic array is reduced by controlling the power devices of the first power conversion circuit according to the output voltage of the first power conversion circuit, the preset voltage upper limit value, the maximum power tracking voltage, the input current of the first power conversion circuit and the input voltage of the first power conversion circuit.

[0030] Preferably, according to the output voltage of the first power conversion circuit, the preset voltage upper limit value, the maximum power tracking voltage, the input current of the first power conversion circuit and the input voltage of the first power conversion circuit, the output power of the photovoltaic array is reduced by controlling the power device of the first power conversion circuit, specifically including:

[0031] Obtaining a first process instruction and a second process instruction according to a difference between an output voltage of the first power conversion circuit and a preset voltage upper limit value, and a difference between an input voltage of the first power conversion circuit and a maximum power tracking voltage;

[0032] Taking the smaller of the first process instruction and the second process instruction as the third process instruction;

[0033] According to the third process instruction and the input current, a pulse width modulation drive signal of each power device in the first power conversion circuit is obtained to reduce the output power of the photovoltaic array.

[0034] It can be seen that this application has the following beneficial effects:

[0035] The power supply system of the photovoltaic heat pump provided by the present application includes: a controller, a first power conversion circuit, a second power conversion circuit and an inverter; the input end of the first power conversion circuit is used to connect to the photovoltaic array; the output end of the first power conversion circuit is connected to the DC bus; the DC end of the inverter is connected to the DC bus; the AC end of the inverter is used to connect to the compressor of the heat pump; the DC end of the second power conversion circuit is connected to the DC bus; the AC end of the second power conversion circuit is used to connect to the power grid; the controller is used to control the first power conversion circuit to reduce the output power of the photovoltaic array when the difference between the output power of the first power conversion circuit and the DC end input power of the second power conversion circuit is greater than the working power of the compressor, that is, when the energy provided by the photovoltaic array is more, to maintain the energy balance of the power supply system. After reducing the output power of the photovoltaic array, the excess power of the photovoltaic array is reduced, the energy of the power supply system is balanced, and the safety and stability are better; compared with the power supply system overvoltage causing the compressor to fail to work normally, the heat energy generated by the heat pump system is also more. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 A schematic diagram of a power supply system of a photovoltaic heat pump provided in an embodiment of the present application;

[0037] Figure 2 A schematic diagram of a controller controlling a first power conversion circuit provided by an embodiment of the present application;

[0038] Figure 3 A schematic diagram of a photovoltaic heat pump system provided in an embodiment of the present application;

[0039] Figure 4 A flow chart of a control method for a photovoltaic heat pump power system provided in an embodiment of the present application;

[0040] Figure 5 A flowchart of another method for controlling a power supply system of a photovoltaic heat pump provided in an embodiment of the present application. DETAILED DESCRIPTION

[0041] In order to enable those skilled in the art to better understand and implement the technical solution of the present application, the specific application scenarios of the present application are introduced below.

[0042] When the power supply system of the heat pump is connected to the photovoltaic array to power the heat pump, in order to obtain higher output power, the maximum power tracking of the photovoltaic array is often performed to enable the photovoltaic array to maintain the maximum power output.

[0043] When the energy provided by the photovoltaic array is greater than the energy required by the compressor of the heat pump, the excess energy will be connected to the grid. However, in order to maintain the stability of the power grid, the power grid often sets a power limit. This results in that when the output power of the photovoltaic array is high, after the compressor is powered, the excess energy cannot be fully connected to the grid, and a part of the electricity generated by the photovoltaic array has to be abandoned, resulting in energy waste and reduced energy utilization. Especially in some scenarios where anti-reverse current rectifiers are used to connect to the grid, energy is not allowed to be connected to the grid, and the phenomenon of photovoltaic power waste is more serious. In addition, the energy that the grid cannot absorb will cause the voltage of the power supply system to rise, resulting in overvoltage faults, and causing the heat pump system to fail to operate normally.

[0044] The embodiments of the present application are further described in detail below in conjunction with the accompanying drawings and specific implementation methods.

[0045] See also Figure 1 , which is a schematic diagram of a power supply system of a photovoltaic heat pump provided in an embodiment of the present application.

[0046] The photovoltaic heat pump power supply system provided in the embodiment of the present application includes: a controller (not shown in the figure), a first power conversion circuit 100, a second power conversion circuit 200 and an inverter 300.

[0047] The input end of the first power conversion circuit 100 is used to connect to the photovoltaic array; the output end of the first power conversion circuit 100 is connected to the DC bus.

[0048] The DC end of the inverter 300 is connected to the DC bus; the AC end of the inverter 300 is used to connect to the compressor of the heat pump.

[0049] The DC end of the second power conversion circuit 200 is connected to the DC bus bus; the AC end of the second power conversion circuit 200 is used to connect to the power grid.

[0050] The controller is used to control the first power conversion circuit 100 to reduce the output power of the photovoltaic array when the difference between the output power of the first power conversion circuit 100 and the DC input power of the second power conversion circuit 200 is greater than the working power of the compressor.

[0051] The difference between the output power of the first power conversion circuit 100 and the DC input power of the second power conversion circuit 200 is greater than the working power of the compressor, that is, the energy provided by the photovoltaic array is greater than the sum of the energy consumed by the compressor and the energy absorbed by the power grid. At this time, the excess energy of the photovoltaic array cannot be absorbed, which will cause the DC bus voltage to increase and cause an overvoltage fault. Therefore, the first power conversion circuit 100 is controlled to reduce the output power of the photovoltaic array to reduce the excess energy generated by the photovoltaic array.

[0052] The present application does not specifically limit the specific topology of the second power conversion circuit 200. The second power conversion circuit 200 can be a power conversion circuit with bidirectional energy flow capability, or a rectifier circuit with anti-reverse flow function, such as an uncontrolled rectifier bridge circuit. When the second power conversion circuit 200 is a rectifier circuit with anti-reverse flow function, the second power conversion circuit 200 does not transmit energy to the power grid, and its DC input power is 0.

[0053] The present application does not specifically limit the specific implementation method of judging that the difference between the output power of the first power conversion circuit 100 and the DC input power of the second power conversion circuit 200 is greater than the working power of the compressor. It should be understood that since the working power of the compressor is a positive number, this embodiment also needs to judge the absolute value of the difference between the output power of the first power conversion circuit 100 and the DC input power of the second power conversion circuit 200 with the working power of the compressor.

[0054] The controller may specifically detect the output power of the first power conversion circuit 100 and the DC input power of the second power conversion circuit 200 respectively, and then compare them with the working power of the compressor.

[0055] The controller can also specifically detect the output voltage of the first power conversion circuit 100, that is, the voltage of the DC bus. It should be understood that when the energy consumed and the energy provided in the power supply system of the heat pump are balanced, the voltage of the DC bus will be stable within a certain value range. When the output voltage of the first power conversion circuit 100 is high, it means that the first power conversion circuit 100 provides more energy.

[0056] In addition to balancing the energy of the power supply system, the first power conversion circuit 100 and the second power conversion circuit 200 are both connected to the DC bus. The electric energy generated by the new energy DC power supply can be supplied to the compressor through the first power conversion circuit 100 and the inverter 300, without the need to first be integrated into the power grid and then perform energy conversion, thereby improving the energy conversion efficiency of the heat pump power supply system.

[0057] The power supply system of the photovoltaic heat pump provided in the embodiment of the present application includes: a controller, a first power conversion circuit, a second power conversion circuit and an inverter; the input end of the first power conversion circuit is used to connect to the photovoltaic array; the output end of the first power conversion circuit is connected to the DC bus; the DC end of the inverter is connected to the DC bus; the AC end of the inverter is used to connect to the compressor of the heat pump; the DC end of the second power conversion circuit is connected to the DC bus; the AC end of the second power conversion circuit is used to connect to the power grid; the controller is used to control the first power conversion circuit to reduce the output power of the photovoltaic array when the difference between the output power of the first power conversion circuit and the DC end input power of the second power conversion circuit is greater than the working power of the compressor, that is, when the energy provided by the photovoltaic array is more, to maintain the energy balance of the power supply system. After reducing the output power of the photovoltaic array, the excess power of the photovoltaic array is reduced, the energy of the power supply system is balanced, and the safety and stability are better; compared with the power supply system overvoltage causing the compressor to fail to work normally, the heat energy generated by the heat pump system is also more.

[0058] In some embodiments, the controller is specifically configured to reduce the output power of the photovoltaic array by controlling the power devices of the first power conversion circuit according to the output voltage of the first power conversion circuit and the input voltage of the first power conversion circuit.

[0059] It should be understood that the output voltage of the first power conversion circuit, that is, the voltage of the DC bus, can be used to determine whether the energy provided by the photovoltaic array is excessive.

[0060] When the photovoltaic array generates little electricity, in order to improve photovoltaic utilization, the maximum power tracking mode is often used to control the photovoltaic array; therefore, in some embodiments, the controller is specifically used to reduce the output power of the photovoltaic array by controlling the power devices of the first power conversion circuit according to the output voltage of the first power conversion circuit, the preset voltage upper limit, the maximum power tracking voltage and the input voltage of the first power conversion circuit.

[0061] The preset voltage upper limit value refers to the upper limit value of the output voltage of the first power conversion circuit. When the output voltage exceeds the preset voltage upper limit value, it indicates that the power provided by the photovoltaic array is excessive.

[0062] Due to the output characteristic curve of the photovoltaic array, the power generated by the photovoltaic array is different under different input voltages. Therefore, the input voltage required to reduce the output power of the first power conversion circuit can be obtained through the maximum power tracking voltage and the input voltage of the first power conversion circuit.

[0063] In some embodiments, the controller can also control the power devices of the first power conversion circuit to reduce the output power of the photovoltaic array based on the output voltage of the first power conversion circuit, the preset voltage upper limit, the maximum power tracking voltage and the input voltage of the first power conversion circuit, as well as the input current of the first power conversion circuit.

[0064] In order to enable those skilled in the art to better understand the technical solution provided by the present application, a control method of a controller for the first power conversion circuit is described in detail below. Figure 2 , which is a schematic diagram of a controller controlling a first power conversion circuit provided in an embodiment of the present application.

[0065] The controller is specifically used to obtain a first process instruction and a second process instruction according to a difference between an output voltage of the first power conversion circuit and a preset voltage upper limit value, and a difference between an input voltage of the first power conversion circuit and a maximum power tracking voltage; take the smaller of the first process instruction and the second process instruction as a third process instruction; and obtain a pulse width modulation (PWM) drive signal of each power device in the first power conversion circuit according to the third process instruction and the input current to reduce the output power of the photovoltaic array.

[0066] The controller specifically includes: a first regulating module 201 , a second regulating module 202 , a third regulating module 203 , a fourth regulating module 204 and a PWM generating module 205 .

[0067] The first regulating module 201 calculates the difference between the output voltage of the first power conversion circuit and the preset voltage upper limit value, and obtains the first process instruction through calculation by the first regulating module 201 .

[0068] The second regulating module 202 calculates the difference between the input voltage of the first power conversion circuit and the maximum power tracking voltage, and obtains the second process instruction through calculation by the second regulating module 202 .

[0069] The third adjustment module 203 compares the first process instruction and the second process instruction, and takes the smaller one as the third process instruction.

[0070] The fourth regulating module 204 calculates the difference between the third process instruction and the input current of the first power conversion circuit, and outputs the PWM driving signal of each power device in the first power conversion circuit through the PWM generating module 205 .

[0071] The present application does not specifically limit the specific implementation method of the third adjustment module 203. For example, the third adjustment module 203 can be implemented by a comparator; it can also be implemented by an adder or a selector.

[0072] When the energy of the photovoltaic array is sufficient, if the output voltage of the first power conversion circuit rises to the preset voltage upper limit, the first process instruction will be reduced due to the first regulation module. When the first process instruction is less than the second process instruction, the controller will control the drive signal of the power device of the first power conversion circuit according to the first process instruction value, thereby achieving the output voltage of the first power conversion circuit, that is, the DC bus voltage is controlled below the preset voltage upper limit.

[0073] However, in addition to the situation where the PV array provides too much energy, when the PV array generates less power or there is a grid failure, the total energy of the PV array and the grid is insufficient to allow the compressor to operate at the required power. The voltage of the DC bus will inevitably drop. In order to ensure that the system can still operate stably, the controller can further control the compressor accordingly.

[0074] The controller is also used to reduce the working power of the compressor when the sum of the output power of the first power conversion circuit and the output power of the second power conversion circuit is less than the required power of the compressor to maintain the energy balance of the power supply system.

[0075] After reducing the working power of the compressor, the power consumed by the compressor is reduced, so that the power supply system has sufficient energy to support the voltage of the DC bus. The energy of the power supply system is balanced, and the safety and stability are better.

[0076] Based on the power supply system of the photovoltaic heat pump provided in the above embodiments, the embodiment of the present application further provides a photovoltaic heat pump system, which is described in detail below in conjunction with the accompanying drawings.

[0077] See also Figure 3 , which is a schematic diagram of a photovoltaic heat pump system provided in an embodiment of the present application.

[0078] The heat pump system provided in the embodiment of the present application includes: a compressor 1000 and a power supply system 2000 of the photovoltaic heat pump introduced in the above embodiment.

[0079] The first end of the photovoltaic heat pump power system 2000 is used to connect to the photovoltaic array.

[0080] The second end of the photovoltaic heat pump power system 2000 is used to connect to the power grid.

[0081] A third end of the power supply system 2000 of the photovoltaic heat pump is connected to the compressor 1000 for supplying power to the compressor 1000 .

[0082] The present application does not specifically limit the specific topological structure of the photovoltaic heat pump system. For example, the photovoltaic heat pump system may also include other components such as an evaporator and a condenser.

[0083] The specific structure of the heat pump power system 2000 and the function of the controller can be found in the above embodiments.

[0084] The heat pump system provided in the embodiment of the present application includes a compressor and the power supply system of the heat pump introduced in the above embodiment. The first end of the power supply system of the heat pump is used to connect to the photovoltaic array, the second end of the power supply system of the heat pump is used to connect to the power grid, and the third end of the power supply system of the heat pump is connected to the compressor to supply power to the compressor. Because the controller of the power supply system can control the first power conversion circuit to reduce the output power of the photovoltaic array when the sum of the output power of the first power conversion circuit and the DC input power of the second power conversion circuit is greater than the working power of the compressor, that is, when the energy provided by the photovoltaic array is relatively large, so that the energy of the power supply system is balanced. Therefore, the photovoltaic heat pump system provided in the embodiment of the present application reduces the occurrence of overvoltage in the power supply system, improves the safety and stability of the heat pump system, and improves the working efficiency of the heat pump system.

[0085] Based on the photovoltaic heat pump power supply system and photovoltaic heat pump system provided in the above embodiments, the embodiment of the present application also provides a control method for the photovoltaic heat pump power supply system, which is described in detail below with reference to the accompanying drawings.

[0086] See also Figure 4 , which is a flow chart of a control method for a photovoltaic heat pump power system provided in an embodiment of the present application.

[0087] The control method provided in the embodiments of the present application is applied to the power supply system of the photovoltaic heat pump introduced in the above embodiments.

[0088] The power supply system is the same as the above embodiment, and includes: a first power conversion circuit, a second power conversion circuit and an inverter.

[0089] The input end of the first power conversion circuit is used to connect to the photovoltaic array; the output end of the first power conversion circuit is connected to the DC bus; the DC end of the inverter is connected to the DC bus; and the AC end of the inverter is used to connect to the compressor of the heat pump.

[0090] The method includes:

[0091] S401: Determine whether the difference between the output power of the first power conversion circuit and the DC input power of the second power conversion circuit is greater than the operating power of the compressor. If yes, execute step S402.

[0092] S402: Control the first power conversion circuit to reduce the output power of the photovoltaic array.

[0093] The difference between the output power of the first power conversion circuit and the DC input power of the second power conversion circuit is greater than the working power of the compressor, that is, the energy provided by the photovoltaic array is greater than the sum of the energy consumed by the compressor and the energy absorbed by the power grid. At this time, the excess energy of the photovoltaic array cannot be absorbed, which will cause the DC bus voltage to increase and cause an overvoltage fault. Therefore, the first power conversion circuit 100 is controlled to reduce the output power of the photovoltaic array to reduce the excess energy generated by the photovoltaic array.

[0094] The control method of the power supply system of the photovoltaic heat pump provided in the embodiment of the present application, the power supply system includes: a controller, a first power conversion circuit, a second power conversion circuit and an inverter; the input end of the first power conversion circuit is used to connect the photovoltaic array; the output end of the first power conversion circuit is connected to the DC bus; the DC end of the inverter is connected to the DC bus; the AC end of the inverter is used to connect the compressor of the heat pump; the DC end of the second power conversion circuit is connected to the DC bus; the AC end of the second power conversion circuit is used to connect the power grid. The method includes: when the difference between the output power of the first power conversion circuit and the DC end input power of the second power conversion circuit is greater than the working power of the compressor, the first power conversion circuit is controlled to reduce the output power of the photovoltaic array to maintain the energy balance of the power supply system. After reducing the output power of the photovoltaic array, the excess power of the photovoltaic array is reduced, the energy of the power supply system is balanced, and the safety and stability are better; compared with the power supply system overvoltage causing the compressor to fail to work normally, the heat energy generated by the heat pump system is also more.

[0095] In some embodiments, the output power of the photovoltaic array can be reduced by controlling the power devices of the first power conversion circuit according to the output voltage of the first power conversion circuit, that is, the voltage of the DC bus, and the input voltage of the first power conversion circuit.

[0096] In some embodiments, under normal circumstances, the first power conversion circuit operates in a maximum power tracking mode. Therefore, when the energy provided by the photovoltaic array is excessive, the output power of the photovoltaic array can be reduced by controlling the power devices of the first power conversion circuit based on the output voltage of the first power conversion circuit, the preset voltage upper limit, the maximum power tracking voltage and the input voltage of the first power conversion circuit.

[0097] Furthermore, the output power of the photovoltaic array is also related to the input current of the first power conversion circuit. Therefore, in some embodiments, the output power of the photovoltaic array can be reduced based on the output voltage of the first power conversion circuit, the preset voltage upper limit, the maximum power tracking voltage, the input current of the first power conversion circuit and the input voltage of the first power conversion circuit.

[0098] See also Figure 5, which is a flow chart of another method for controlling a power supply system of a photovoltaic heat pump provided in an embodiment of the present application.

[0099] The topology and connection relationship of the power supply system can be found in the above embodiments and will not be described in detail here.

[0100] The method includes:

[0101] S501: Determine, based on the output voltage of the first power conversion circuit, that the difference between the output power of the first power conversion circuit and the input power of the second power conversion circuit is greater than the operating power of the compressor.

[0102] It should be understood that when the energy consumed and the energy provided in the power supply system of the heat pump are balanced, the output voltage of the first power conversion circuit, that is, the voltage of the DC bus, will be stable within a certain value range. When the output voltage of the first power conversion circuit is high, it means that the first power conversion circuit provides more energy.

[0103] S502: Obtain a first process instruction and a second process instruction according to a difference between an output voltage of the first power conversion circuit and a preset voltage upper limit value, and a difference between an input voltage of the first power conversion circuit and a maximum power tracking voltage.

[0104] S503: Take the smaller one of the first process instruction and the second process instruction as the third process instruction.

[0105] S504: Obtain a pulse width modulation drive signal for each power device in the first power conversion circuit according to the third process instruction and the input current, so as to reduce the output power of the photovoltaic array.

[0106] It should be noted that the various embodiments in this specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the various embodiments can be referenced to each other.

[0107] The above description of the disclosed embodiments enables those skilled in the art to implement or use the present application. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application will not be limited to the embodiments shown herein, but will conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A photovoltaic heat pump power supply system, characterized in that: include: A controller, a first power conversion circuit, a second power conversion circuit and an inverter; wherein the second power conversion circuit has a bidirectional energy flow capability; The input end of the first power conversion circuit is used to connect to the photovoltaic array; the output end of the first power conversion circuit is connected to the DC bus; the DC end of the inverter is connected to the DC bus; the AC end of the inverter is used to connect to the compressor of the heat pump; the DC end of the second power conversion circuit is connected to the DC bus; the AC end of the second power conversion circuit is used to connect to the power grid; The controller is used to obtain a first process instruction and a second process instruction according to a difference between an output voltage of the first power conversion circuit and a preset voltage upper limit value, and a difference between an input voltage of the first power conversion circuit and a maximum power tracking voltage when the difference between the output power of the first power conversion circuit and the DC end input power of the second power conversion circuit is greater than the working power of the compressor, and take the smaller of the first process instruction and the second process instruction as a third process instruction; obtain a pulse width modulation drive signal of each power device in the first power conversion circuit according to the third process instruction and the input current of the first power conversion circuit, and control the first power conversion circuit to reduce the output power of the photovoltaic array; wherein, when the output voltage of the first power conversion circuit is less than the preset voltage upper limit value, the first process instruction is greater than the second process instruction, and when the output voltage of the first power conversion circuit is greater than or equal to the preset voltage upper limit value, the first process instruction is less than the second process instruction.

2. The power supply system according to claim 1, characterized in that: The controller is also used to reduce the operating power of the compressor when the sum of the output power of the first power conversion circuit and the output power of the second power conversion circuit is less than the required power of the compressor, so as to maintain the energy balance of the power supply system.

3. A photovoltaic heat pump system, characterized in that: include: A compressor and a power supply system of a photovoltaic heat pump as claimed in claim 1 or 2; The first end of the power supply system is used to connect to a photovoltaic array; The second end of the power supply system is used to connect to the power grid; The third end of the power supply system is connected to the compressor for supplying power to the compressor.

4. A control method for a photovoltaic heat pump power supply system, characterized in that: The power supply system comprises: a first power conversion circuit, a second power conversion circuit and an inverter; wherein the second power conversion circuit has a bidirectional energy flow capability; the input end of the first power conversion circuit is used to connect to a photovoltaic array; the output end of the first power conversion circuit is connected to a DC bus; the DC end of the inverter is connected to the DC bus; the AC end of the inverter is used to connect to a compressor of the heat pump; The method comprises: When the difference between the output power of the first power conversion circuit and the DC input power of the second power conversion circuit is greater than the working power of the compressor, a first process instruction and a second process instruction are obtained according to the difference between the output voltage of the first power conversion circuit and a preset voltage upper limit value, and the difference between the input voltage of the first power conversion circuit and a maximum power tracking voltage, and the smaller of the first process instruction and the second process instruction is taken as the third process instruction; wherein, when the output voltage of the first power conversion circuit is less than the preset voltage upper limit value, the first process instruction is greater than the second process instruction, and when the output voltage of the first power conversion circuit is greater than or equal to the preset voltage upper limit value, the first process instruction is less than the second process instruction; According to the third process instruction and the input current of the first power conversion circuit, a pulse width modulation drive signal of each power device in the first power conversion circuit is obtained, and the first power conversion circuit is controlled to reduce the output power of the photovoltaic array.

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