Photovoltaic power generation system and heating system

Abstract

This utility model relates to a photovoltaic power generation system and a heating system. The photovoltaic power generation system includes photovoltaic modules, a voltage detection module for detecting the output voltage of the photovoltaic modules, a regulated power supply module connected to the voltage output terminal of the photovoltaic modules, and a load impedance module. The load impedance module is configured to perform impedance operation under control and to adjust its own impedance when performing impedance operation. A control module is connected to the voltage detection module, the regulated power supply module, and the load impedance module respectively. The control module is configured to control the load impedance module according to the voltage detection status of the voltage detection module, so as to realize that the load impedance module adjusts its own impedance and realizes that the photovoltaic modules operate near the maximum power point. In this way, not only can the photovoltaic modules be ensured to operate near the maximum power point, improving the photovoltaic power generation efficiency, but also the use of water as a medium to replace the energy storage battery has a longer cycle life and eliminates the safety risk of battery thermal runaway.

Description

Technical Field

[0001] This utility model relates to the field of photovoltaic power generation, and in particular to a photovoltaic power generation system and a heating system. Background Technology

[0002] Photovoltaic power generation, as a clean power generation technology, has been widely promoted and applied, and photovoltaic power generation systems have been used in various scenarios.

[0003] In the operation of a photovoltaic (PV) power generation system, PV power generation is a nonlinear process, and the current-voltage characteristic of PV modules is not a linear curve. Therefore, to maximize the power generation efficiency of a PV system, a maximum power point tracker (MPPT) is typically used to track the maximum power point of the PV system under the given illumination conditions. This MPPT adjusts the load impedance in real time to keep the PV modules operating near their maximum power point, thereby maximizing power generation efficiency. The MPPT requires energy storage batteries (such as lithium-ion or lead-acid batteries) to perform the maximum power point tracking function.

[0004] However, existing photovoltaic power generation methods have shortcomings: maximum power point trackers have a short lifespan and require energy storage batteries to function properly. However, energy storage batteries have a limited cycle life and are subject to thermal runaway risks, which greatly increases the safety risks of the photovoltaic power generation process.

[0005] Therefore, it is necessary to provide an alternative photovoltaic power generation method to overcome the shortcomings of existing photovoltaic power generation methods based on maximum power point trackers. Utility Model Content

[0006] In view of this, the first technical problem to be solved by this utility model is to provide a photovoltaic power generation system that can replace the maximum power point tracker and adjust the load impedance in real time to maximize power generation efficiency.

[0007] The second technical problem to be solved by this utility model is to provide a heating system that applies the above-mentioned photovoltaic power generation system.

[0008] The technical solution adopted by this utility model to solve the first technical problem is: a photovoltaic power generation system, characterized in that it includes:

[0009] Photovoltaic modules are configured to convert solar energy into electrical energy;

[0010] The voltage detection module is connected to the voltage output terminal of the photovoltaic module and is configured to detect the output voltage of the photovoltaic module.

[0011] A voltage regulator module, the input of which is connected to the voltage output of the photovoltaic module;

[0012] The load impedance module, connected to the voltage output terminal of the photovoltaic module, is configured to perform impedance operation under control and to adjust its own impedance when performing impedance operation.

[0013] The control module, which is connected to the voltage detection module, the regulated power supply module and the load impedance module respectively, is configured to control the load impedance module according to the voltage detection status of the voltage detection module, so as to enable the load impedance module to adjust its own impedance and enable the photovoltaic module to operate near the maximum power point.

[0014] As a first implementation of the load impedance module, in the photovoltaic power generation system of this utility model, the load impedance module includes a first resistor, a second resistor, a first control switch, and a second control switch; wherein:

[0015] A first resistor is configured such that its first terminal is connected to the positive terminal of the photovoltaic module via a first control switch, and its second terminal is connected to the negative terminal of the photovoltaic module; wherein the positive terminal of the photovoltaic module is the voltage output terminal of the photovoltaic module.

[0016] The second resistor is configured such that its first terminal is connected to the positive terminal of the photovoltaic module via a second control switch, and its second terminal is connected to the negative terminal of the photovoltaic module; wherein the second resistor and the first resistor are connected in parallel, and the resistance of the first resistor is greater than the resistance of the second resistor.

[0017] The control module is connected to the first control switch and the second control switch respectively to control the switching action of the first control switch and the switching action of the second control switch.

[0018] As a second implementation of the load impedance module, in the photovoltaic power generation system of this utility model, the load impedance module includes a first resistor, a second resistor, a first control switch, a second control switch, and a third control switch; wherein:

[0019] The first resistor is configured such that its first terminal is connected to the positive terminal of the photovoltaic module via a third control switch; wherein the positive terminal of the photovoltaic module is the voltage output terminal of the photovoltaic module.

[0020] The first control switch is connected in parallel across the first resistor;

[0021] A second resistor is configured such that its first end is connected to the second end of the first resistor, and the second end of the second resistor is connected to the negative terminal of the photovoltaic module; wherein the resistance of the first resistor is greater than the resistance of the second resistor.

[0022] The second control switch is connected in parallel across the two ends of the second resistor, and the second control switch is connected in series with the first control switch.

[0023] The control module is connected to the first control switch, the second control switch, and the third control switch to control the switching action of the first control switch, the second control switch, and the third control switch.

[0024] As a third implementation of the load impedance module, in the photovoltaic power generation system of this utility model, the load impedance module includes a first resistor, a second resistor, a first control switch, a second control switch, a third control switch, and a fourth control switch; wherein:

[0025] A first resistor is configured such that its first terminal is connected to the positive terminal of the photovoltaic module via a first control switch, and its second terminal is connected to the negative terminal of the photovoltaic module via a third control switch; wherein, the positive terminal of the photovoltaic module is the voltage output terminal of the photovoltaic module.

[0026] The second resistor is configured such that its first end is connected to the second end of the first resistor, the second end of the second resistor is connected to the negative terminal of the photovoltaic module through a second control switch, and the second end of the second resistor is also connected to the positive terminal of the photovoltaic module through a fourth control switch; the resistance value of the first resistor is greater than the resistance value of the second resistor.

[0027] The control module is connected to the first control switch, the second control switch, the third control switch and the fourth control switch respectively, so as to control the switching action of the first control switch, the second control switch, the third control switch and the fourth control switch.

[0028] In a further improvement, the photovoltaic power generation system in this invention also includes a delay module. The input terminal of the delay module is connected to the command output terminal of the control module, and the output terminal of the delay module is connected to the first control switch and the second control switch respectively.

[0029] Furthermore, in the photovoltaic power generation system, the voltage detection module includes a diode, a current-limiting resistor, and a voltage-stabilizing capacitor connected in series. The positive terminal of the diode is connected to the positive terminal of the photovoltaic module, and the negative terminal of the diode is connected to the first terminal of the voltage-stabilizing capacitor through the current-limiting resistor. The second terminal of the voltage-stabilizing capacitor is connected to the negative terminal of the photovoltaic module.

[0030] Alternatively, in the photovoltaic power generation system, the voltage detection module includes a diode, a current-limiting resistor, and a voltage-stabilizing capacitor connected in series. The positive terminal of the diode is connected to the positive terminal of the photovoltaic module, and the negative terminal of the diode is connected to the first terminal of the voltage-stabilizing capacitor through the current-limiting resistor. The second terminal of the voltage-stabilizing capacitor is connected to the negative terminal of the photovoltaic module. The voltage detection module is connected to the positive terminal of the photovoltaic module through a DC circuit breaker, and the first terminal of the current-limiting resistor and the second terminal of the voltage-stabilizing capacitor are respectively connected to the control module.

[0031] The technical solution adopted by this utility model to solve the second technical problem is: a heating system, including an energy storage device containing a water medium, characterized in that it applies any of the photovoltaic power generation systems described in the present invention.

[0032] Improved in this invention, the heating system further includes:

[0033] A heating device is installed in the energy storage device to heat the water medium in the energy storage device;

[0034] A temperature detection device is configured to detect the temperature of the water medium in the energy storage device.

[0035] In a further improvement, the heating system in this invention also includes:

[0036] A cold water inlet pipe, one end of which is connected to the water inlet of the energy storage device, and the second end of which is configured to be connected to a tap water pipe;

[0037] A hot water outlet pipe, one end of which is connected to the outlet of the energy storage device, and the second end of which is configured to connect to the user's hot water usage end.

[0038] In a further improvement, the heating system in this invention also includes at least one of the following: a cooling fan, corrosion-resistant components, an over-temperature and over-pressure safety valve, and a temperature display; wherein:

[0039] The cooling fan is configured to operate to ventilate and dissipate heat from the space where the control module is located;

[0040] The corrosion-resistant component is configured to have a portion disposed in the aqueous medium of the energy storage device to prevent the devices in the energy storage device from being subjected to electro-corrosion.

[0041] An over-temperature and over-pressure safety valve is configured to connect to a control module to automatically open and release pressure when the temperature of the water medium in the energy storage device exceeds a specified temperature value or the water pressure exceeds a specified water pressure value.

[0042] Compared with the prior art, the advantages of this utility model are:

[0043] First, the photovoltaic power generation system of this utility model adds a load impedance module based on the existing photovoltaic module, which is formed by a first resistor, a second resistor, a controlled first control switch, and a second control switch. By utilizing the series, parallel, and series-parallel relationships formed between the first resistor and the second resistor, and in conjunction with the switching action of the corresponding control switch, the load adjustment of the load impedance module formed under each relationship is completed respectively, ensuring that the photovoltaic module operates near the maximum power point and improving the photovoltaic power generation efficiency.

[0044] Secondly, by ensuring that at least one of the heating resistors in the first and second resistors of the photovoltaic power generation system is always connected to the photovoltaic module, this invention ensures that the output of the photovoltaic module will not be in an open circuit state. This avoids the continuous and rapid jump between the output voltage of the photovoltaic module and the open circuit value when the last heating resistor is put in or removed under extremely weak light conditions, thereby enhancing the safety of the entire photovoltaic system. Attached Figure Description

[0045] To more clearly illustrate the technical solutions in the specific embodiments of this disclosure or the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this disclosure. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0046] Figure 1 This is a schematic diagram of the photovoltaic power generation method in Embodiment 1 of this utility model;

[0047] Figure 2 This is a schematic diagram of the photovoltaic power generation system in Embodiment 1 of this utility model;

[0048] Figure 3 This is a schematic diagram of the heating system in Embodiment 1 of this utility model;

[0049] Figure 4 This is a schematic diagram of the photovoltaic power generation system in Embodiment 2 of this utility model;

[0050] Figure 5 This is a schematic diagram of the photovoltaic power generation system in Embodiment 3 of this utility model. Detailed Implementation

[0051] To make the objectives, technical solutions, and advantages of the embodiments of this utility model clearer, the technical solutions of the embodiments of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this utility model, not all embodiments. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of this utility model.

[0052] To facilitate understanding of the embodiments of this utility model, the following will provide further explanation and description with reference to the accompanying drawings and specific embodiments. These embodiments do not constitute a limitation on the embodiments of this utility model.

[0053] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments.

[0054] Example 1

[0055] This embodiment provides a photovoltaic power generation method. Specifically, see [link to documentation]. Figure 1 As shown, the photovoltaic power generation method in this embodiment includes the following steps:

[0056] Step 1: Detect the output voltage of the photovoltaic module and the temperature of the water medium in the water-based energy storage device connected to the photovoltaic power generation output terminal; wherein, in this embodiment, the detected output voltage of the photovoltaic module is denoted as U. S The detected water medium temperature in the energy storage device is marked as T;

[0057] Step 2: Make a judgment based on the detected output voltage of the photovoltaic module:

[0058] When the output voltage of the photovoltaic module reaches the minimum input voltage of the regulated power supply, the load impedance adjustment is performed to enable the photovoltaic module to operate near the maximum power point; otherwise, proceed to step 1. The maximum allowable input voltage of the regulated power supply should be greater than the maximum open-circuit voltage of the photovoltaic module and be able to adapt to changes in the output voltage of the photovoltaic module. For example, the output voltage of the regulated power supply is 5V or 12V, and the output current of the regulated power supply should meet the power capacity requirements of the logic judgment and control circuit.

[0059] For example, in this embodiment, it is assumed that the minimum input voltage of the regulated power supply is labeled U. th So, when the output voltage U of the photovoltaic module S The minimum input voltage U of the regulated power supply th At that time, i.e., U S ≥U th When this occurs, load impedance adjustment is performed to ensure that the photovoltaic modules operate near their maximum power point;

[0060] Step 3: Make a judgment based on whether the detected water medium temperature in the water medium energy storage device is within the preset temperature range:

[0061] When the water medium temperature is within the preset temperature range, load impedance adjustment is performed to enable the photovoltaic module to operate near the maximum power point; otherwise, proceed to step 4; wherein, the preset temperature range is the temperature interval defined by the preset upper limit temperature value and the preset lower limit temperature value; the preset upper limit temperature value is greater than the preset lower limit temperature value;

[0062] For example, in this embodiment, the maximum power point of the photovoltaic module during operation is denoted as P. m The voltage corresponding to the photovoltaic module operating at its maximum power point is denoted as U. m The current corresponding to the photovoltaic module when operating at its maximum power point is denoted as I. mThe preset temperature range is marked as (T1, T2), where T1 is the preset upper limit temperature value and T2 is the preset lower limit temperature value, and T1 > T2. If the detected water medium temperature T does not reach the preset upper limit temperature value T1, load impedance adjustment is performed to ensure the photovoltaic module operates at its maximum power point P. m Operating nearby;

[0063] Step 4: Make another judgment based on the detected water medium temperature in the water medium energy storage device:

[0064] When the water medium temperature reaches the preset upper limit temperature value, the control load impedance does not perform impedance operation; otherwise, the control load impedance continues to perform load impedance adjustment operation to enable the photovoltaic module to operate near the maximum power point.

[0065] In other words, in this embodiment, when the detected water medium temperature T≥T1, it means that the water temperature has risen to the preset upper limit temperature, and the control load impedance does not perform impedance operation, so the photovoltaic power generation will no longer output electrical energy; otherwise, when T≤T2, it means that the water temperature has dropped to the preset lower limit temperature, and the control load impedance continues to perform load impedance adjustment operation to realize that the photovoltaic module operates near the maximum power point.

[0066] In addition, this embodiment also provides a photovoltaic power generation system for implementing the above-described photovoltaic power generation method. Specifically, see [link to documentation]. Figure 2 As shown, the photovoltaic power generation system of this embodiment includes a photovoltaic module 11, a voltage detection module 12, a voltage regulator module 13, a load impedance module 14, and a control module 15. Wherein:

[0067] Photovoltaic module 11 is configured to convert solar energy into electrical energy; wherein, in this embodiment, various forms of photovoltaic modules can be used, such as photovoltaic panels, photovoltaic tiles, photovoltaic glass, flexible photovoltaic panels, etc.

[0068] For example, in this embodiment, two 550W photovoltaic modules are connected in parallel, and the electrical performance parameters of the photovoltaic modules are as follows:

[0069] Maximum power (Pmax): 550W

[0070] Open circuit voltage (Voc): 51.8V

[0071] Maximum power point voltage (Vmp): 41.4V

[0072] Short-circuit current (Isc): 16.47A

[0073] Maximum power point current (Imp): 13.29A

[0074] The voltage detection module 12 is connected to the voltage output terminal of the photovoltaic module 11 and is configured to detect the output voltage of the photovoltaic module.

[0075] The input terminal of the voltage regulator module 13 is connected to the voltage output terminal of the photovoltaic module 11;

[0076] The load impedance module 14 is connected to the voltage output terminal of the photovoltaic module 11 and is configured to perform impedance operation or not after being controlled and to adjust its own impedance when performing impedance operation.

[0077] The control module 15 is connected to the voltage detection module 12, the regulated power supply module 13 and the load impedance module 14 respectively. It is configured to control the load impedance module according to the voltage detection of the voltage detection module, so as to realize the load impedance module to adjust its own impedance and realize the photovoltaic module to operate near the maximum power point.

[0078] In other words, in this embodiment, the control module controls the load impedance module in the following way:

[0079] When the control module determines that the output voltage of the photovoltaic module detected by the voltage detection module has reached the minimum input voltage of the regulated power supply, it performs load impedance adjustment to enable the photovoltaic module to operate near the maximum power point.

[0080] When the control module determines that the temperature of the water medium in the water medium energy storage device is within the preset temperature range, it performs load impedance adjustment to enable the photovoltaic module to operate near the maximum power point.

[0081] When the control module determines that the temperature of the water medium in the water medium energy storage device has reached the preset upper limit temperature value, it controls the load impedance to not perform impedance adjustment; otherwise, it controls the load impedance to continue to perform load impedance adjustment to enable the photovoltaic module to operate near the maximum power point.

[0082] In the photovoltaic power generation system of this embodiment, see Figure 2 As shown, the load impedance module 14 includes a first resistor R1, a second resistor R2, a first control switch K1, and a second control switch K2; wherein:

[0083] The first resistor R1 is configured such that its first terminal is connected to the positive terminal of the photovoltaic module 11 through the first control switch K1, and the second terminal of the first resistor R1 is connected to the negative terminal of the photovoltaic module 11; wherein, the positive terminal of the photovoltaic module is the voltage output terminal of the photovoltaic module.

[0084] The second resistor R2 is configured such that its first terminal is connected to the positive terminal of the photovoltaic module 11 via the second control switch K2, and its second terminal is connected to the negative terminal of the photovoltaic module 11; wherein the second resistor R2 is connected in parallel with the first resistor R1, and the resistance value of the first resistor R1 is greater than the resistance value of the second resistor R2; for example, in this embodiment, the first resistor R1 = 5Ω, rated power 500W; the second resistor R2 = 2.5Ω, rated power 1000W;

[0085] The control module 15 is connected to the first control switch K1 and the second control switch K2 to control the switching actions of the first and second control switches. In this embodiment, the first control switch K1 is a normally closed switch, and the second control switch K2 is a normally open switch.

[0086] To meet the delay control requirements of the control module for the first and second control switches, the photovoltaic power generation system in this embodiment also includes a delay module (not shown in the figure). The input terminal of the delay module is connected to the command output terminal of the control module 15, and the output terminal of the delay module is connected to the first control switch K1 and the second control switch K2, respectively. The delay length of the delay module can be set as needed.

[0087] As a method for voltage detection, in the photovoltaic power generation system of this embodiment, see... Figure 2 As shown, the voltage detection module 12 in this embodiment includes a diode D, a current-limiting resistor R, and a voltage-stabilizing capacitor C connected in series. The positive terminal of the diode D is connected to the positive terminal of the photovoltaic module 11, and the negative terminal of the diode D is connected to the first terminal of the voltage-stabilizing capacitor C through the current-limiting resistor R. The second terminal of the voltage-stabilizing capacitor C is connected to the negative terminal of the photovoltaic module 11. To protect electrical appliances, the photovoltaic power generation system in this embodiment also includes a DC circuit breaker QF. The voltage detection module 12 is connected to the positive terminal of the photovoltaic module 11 through the DC circuit breaker QF, and the first terminal of the current-limiting resistor R and the second terminal of the voltage-stabilizing capacitor C are respectively connected to the control module 15.

[0088] The voltage regulator module 13 serves as the power source for the power generation control system. One end of the voltage regulator module 13 is connected to the positive terminal of the photovoltaic module 11 via a DC circuit breaker QF, and the other end of the voltage regulator module 13 is connected to the negative terminal of the photovoltaic module.

[0089] This embodiment also provides a heating system that utilizes the aforementioned photovoltaic power generation system. Specifically, see [link to documentation]. Figure 3As shown, the heating system of this embodiment includes an energy storage device 20 containing a water medium, a heating device 21, and a temperature detection device 22. The heating device 21 is disposed in the energy storage device 20 to heat the water medium in the energy storage device 20; the temperature detection device 22 is configured to detect the temperature of the water medium in the energy storage device 20. For example, in this embodiment, the heating device 21 is a heating rod used to convert the electrical energy generated by the photovoltaic power generation system into heat energy. Of course, by using two or more heating rods in combination, the photovoltaic module can be made to operate as close as possible to its maximum power point, thereby improving the power generation efficiency of the photovoltaic module. As needed, a temperature control module 15' can be provided, and the temperature control module 15' is connected to the temperature detection device 22 and the control module 15 respectively.

[0090] In this embodiment, the energy storage device for holding the water medium is a pressurized and insulated water tank, which is used to hold hot water.

[0091] Of course, the photovoltaic power generation system in this embodiment can also include a cold water inlet pipe 23 and a hot water outlet pipe 24. One end of the cold water inlet pipe 23 is connected to the inlet of the energy storage device, and the second end of the cold water inlet pipe 23 is configured to connect to a tap water pipe. One end of the hot water outlet pipe 24 is connected to the outlet of the energy storage device, and the second end of the hot water outlet pipe 24 is configured to connect to the user's hot water outlet. For example, the user's hot water outlet can be a shower faucet.

[0092] In this embodiment, the heating system may also include a controlled cooling fan 16 to provide ventilation and heat dissipation to the space where the control module is located.

[0093] Depending on actual needs, anti-corrosion components 25 can also be installed in the water medium of the energy storage device 20 to prevent the components in the energy storage device from being subjected to electro-corrosion. For example, the anti-corrosion component 25 here is a magnesium rod, part of which is placed in the water medium of the energy storage device, thus preventing components such as the water tank liner and heating rod from being subjected to electro-corrosion.

[0094] Of course, an over-temperature and over-pressure safety valve 26 can also be installed on the energy storage device. This over-temperature and over-pressure safety valve 26 is configured to connect to the control module so that it automatically opens to release pressure when the temperature of the water medium in the energy storage device exceeds the specified temperature value or the water pressure exceeds the specified water pressure value.

[0095] To facilitate understanding of the real-time temperature of the water medium in the energy storage device, a temperature display 27 can also be installed on the energy storage device in the heating system of this embodiment, so as to display the water medium temperature in the energy storage device detected by the temperature detection device using the temperature display 27.

[0096] The following combination Figure 2 and Figure 3 The heating control method process of the heating system in this embodiment is described below:

[0097] Step S1: In the initial state, when the photovoltaic module does not output electrical energy, the first control switch K1 (normally closed switch) and the second control switch K2 (normally open switch) do not operate. The first resistor R1 (heating resistor) is connected to the circuit, and the second resistor R2 (heating resistor) is disconnected.

[0098] Step S2: As the ambient light around the photovoltaic module increases, the output voltage of the photovoltaic module begins to rise. When the output voltage of the photovoltaic module reaches the minimum input voltage requirement of the voltage regulator module, the voltage output by the voltage regulator module enables the logic judgment and control circuit to start working normally.

[0099] Step S3: The voltage detection module determines whether to output an action signal by detecting the output voltage Us of the photovoltaic module.

[0100] When the output voltage of the photovoltaic module continues to rise, and the output voltage Us of the photovoltaic module approaches the voltage Um value of the saturation range, the first action voltage value of the voltage detection module is reached. The voltage detection module outputs an action signal to the delay module. After receiving the action signal, the delay module sends a control signal to the control circuit of the first control switch K1 and the second control switch K2 after a delay of time t1. This causes both the first control switch K1 and the second control switch K2 to act, thereby connecting the second resistor R2 into the circuit and disconnecting the first resistor R1.

[0101] When the output voltage of the photovoltaic module continues to rise, and the output voltage Us of the photovoltaic module approaches the voltage Um value of the saturation range again, the second action voltage value of the voltage detection module is reached. The voltage detection module also outputs an action signal to the delay module. After receiving the action signal, the delay module sends a control signal to the control loop of the first control switch K1 and the second control switch K2 after a delay of t3. This causes the first control switch K1 to return and the second control switch K2 to activate, thereby connecting the first resistor R1 and the second resistor R2 in parallel to the circuit.

[0102] When the output voltage of the photovoltaic module decreases, the output voltage Us of the photovoltaic module reaches the second return voltage value of the voltage detection module. At this time, the voltage detection module outputs an action signal and returns. After a delay of t4, it sends a control signal to the control loop of the first control switch K1 and the second control switch K2. Both the first control switch K1 and the second control switch K2 are activated, thereby connecting the second resistor R2 into the circuit and disconnecting the first resistor R1.

[0103] When the output voltage of the photovoltaic module continues to drop, the output voltage Us of the photovoltaic module reaches the first return voltage value of the voltage detection module; at this time, the voltage detection module outputs an action signal and returns. After a delay of time t2, the control signal is given to the control circuits of the first control switch K1 and the second control switch K2. The first control switch K1 and the second control switch K2 do not act, the first resistor R1 is connected to the circuit, and the second resistor R2 is disconnected;

[0104] Step S4, at any time, when the temperature detection device detects that the water temperature in the energy storage device reaches the preset upper limit temperature value, the control module outputs an action signal and gives the control signal to the control circuits of the first control switch K1 and the second control switch K2 without delay, so that after the first control switch K1 acts, the first resistor R1 is disconnected and after the second control switch K2 returns, the second resistor R2 is disconnected; at this time, both heating resistors R1 and R2 do not work.

[0105] When the temperature detection device detects that the water temperature in the energy storage device drops to the preset lower limit temperature value, the action signal output by the temperature detection device returns, and the control signal is given to the control circuits of the first control switch K1 and the second control switch K2 without delay, so that the first control switch K1 and the second control switch K2 act according to the output results of the control logic in steps S1 to S3, and the two heating resistors R1 and R2 work according to the logic control results.

[0106] It should be noted that in this embodiment, the set values of the action delay times t1 and t3 are such that t1 < t3; the set values of the return delay times t2 and t4 are such that t2 > t4. Specifically, the set values of the action delay times t1 and t3 are set to 30 seconds and 45 seconds respectively; the set values of the return delay times t2 and t4 are set to 3 seconds and 0 seconds respectively.

[0107] Among them, the action voltage and the return voltage need to be set according to the electrical performance parameters of the photovoltaic module and the resistance value of the heating resistor, so that the photovoltaic module can output a larger power generation power under the current light conditions.

[0108] Embodiment 2

[0109] This embodiment provides a photovoltaic power generation method. Among them, the specific implementation manner of this photovoltaic power generation method is as described in Embodiment 1, and will not be elaborated here.

[0110] This embodiment also provides a photovoltaic power generation system for implementing the above photovoltaic power generation method. The difference from the photovoltaic power generation system in Embodiment 1 is that in this Embodiment 2, as shown in Figure 4 shown, the load impedance module 14 includes a first resistor R1, a second resistor R2, a first control switch K1, a second control switch K2 and a third control switch K3; where:

[0111] The first resistor R1 is configured such that its first terminal is connected to the positive terminal of the photovoltaic module 11 via the third control switch K3; wherein, the positive terminal of the photovoltaic module is the voltage output terminal of the photovoltaic module.

[0112] The first control switch K1 is connected in parallel across the first resistor R1;

[0113] The second resistor R2 is configured such that its first end is connected to the second end of the first resistor R1, and the second end of the second resistor R2 is connected to the negative terminal of the photovoltaic module 11; wherein the resistance of the first resistor R1 is greater than the resistance of the second resistor R2.

[0114] The second control switch K2 is connected in parallel across the two ends of the second resistor R2, and the second control switch K2 is connected in series with the first control switch K1.

[0115] The control module 15 is connected to the first control switch K1, the second control switch K2 and the third control switch K3 respectively, so as to control the switching action of the first control switch, the switching action of the second control switch and the switching action of the third control switch.

[0116] This embodiment also provides a heating system that utilizes the aforementioned photovoltaic power generation system. Specifically, refer to the heating system described in Embodiment 1.

[0117] The following combination Figure 4 The heating control method process of the heating system in this embodiment is described below:

[0118] Step a1: In the initial state, when the photovoltaic module has no output, the third control switch K3 (normally closed switch), the first control switch K1 (normally open switch), and the second control switch K2 (normally open switch) are all inactive. The first resistor R1 (heating resistor) and the second resistor R2 (heating resistor) are connected in series and then connected to the circuit.

[0119] Step a2: As the ambient light around the photovoltaic module increases, the output voltage of the photovoltaic module begins to rise. When the output voltage of the photovoltaic module reaches the minimum input voltage requirement of the voltage regulator module, the voltage output by the voltage regulator module enables the logic judgment and control circuit to start working normally.

[0120] Step a3: The voltage detection module determines whether to output an action signal by detecting the output voltage Us of the photovoltaic module.

[0121] When the output voltage of the photovoltaic module continues to rise, and the output voltage Us of the photovoltaic module approaches the Um value of the saturation range, the first action voltage value of the voltage detection module is reached. At this time, the voltage detection module outputs an action signal to the delay module. After receiving the signal, the delay module sends a control signal to the control circuit of the second control switch K2 after a delay of time t1, causing the second control switch K2 to close, thereby short-circuiting the second resistor R2. At this time, only the first resistor R1 is connected to the main circuit.

[0122] When the output voltage of the photovoltaic module continues to rise, and the output voltage Us of the photovoltaic module approaches the Um value of the saturation range again, it reaches the second action voltage value of the voltage detection module. At this time, the voltage detection module also outputs an action signal to the delay module. After receiving the signal, the delay module sends a control signal to the control circuit of the first control switch K1 and the second control switch K2 after a delay of t3. This causes the first control switch K1 to close and the second control switch K2 to open, thereby short-circuiting the first resistor R1. At this time, only the second resistor R2 is connected to the circuit.

[0123] When the output voltage of the photovoltaic module decreases, the output voltage Us of the photovoltaic module reaches the second return voltage value of the voltage detection module. At this time, the voltage detection module outputs an action signal and returns. After a delay of t4, it sends a control signal to the control circuit of the first control switch K1 and the second control switch K2. The first control switch K1 returns to open and the second control switch K2 closes, thereby connecting the first resistor R1 into the circuit and short-circuiting the second resistor R2.

[0124] When the output voltage of the photovoltaic module continues to decrease, the output voltage Us of the photovoltaic module reaches the first return voltage value of the voltage detection module. At this time, the voltage detection module outputs an action signal and returns. After a delay of t2, the control signal is sent to the control loop of the first control switch K1 and the second control switch K2. Both the first control switch K1 and the second control switch K2 return to open, and the first resistor R1 and the second resistor R2 are connected in series in the circuit.

[0125] Step a4: At any time, when the temperature detection device detects that the water temperature in the energy storage device has reached the preset upper limit temperature value, the control module outputs an action signal and sends the control signal to the control circuit of the third control switch K3 without delay, so that the third control switch K3 cuts off the main circuit after it is activated; at this time, the first resistor R1 and the second resistor R2 are not working.

[0126] When the temperature detection device detects that the water temperature in the energy storage device has dropped to the preset lower limit temperature value, the control module outputs an action signal and returns. Without delay, the control signal is sent to the control circuit of the third control switch K3, so that the third control switch K3 returns and connects the main circuit. The first control switch K1 and the second control switch K2 operate according to the logic output results of steps a1 to a3; the first resistor R1 and the second resistor R2 work according to the logic control results.

[0127] The first control switch K1 and the second control switch K2 must be interlocked to ensure that only one of the two switches (K1 and K2) can be closed at the same time; otherwise, the output of the photovoltaic module will be short-circuited.

[0128] Example 3

[0129] This embodiment provides a photovoltaic power generation method. The specific implementation of this photovoltaic power generation method is described in Embodiment 1, and will not be repeated here.

[0130] This embodiment also provides a photovoltaic power generation system for implementing the above-described photovoltaic power generation method. The difference between this embodiment and the photovoltaic power generation system in Embodiment 1 is that, in this Embodiment 3, see... Figure 5 As shown, the load impedance module 14 includes a first resistor R1, a second resistor R2, a first control switch K1, a second control switch K2, a third control switch K3, and a fourth control switch K4. Wherein:

[0131] The first resistor R1 is configured such that its first terminal is connected to the positive terminal of the photovoltaic module 11 through the first control switch K1, and the second terminal of the first resistor R1 is connected to the negative terminal of the photovoltaic module 11 through the third control switch K3; wherein, the positive terminal of the photovoltaic module is the voltage output terminal of the photovoltaic module.

[0132] The second resistor R2 is configured such that its first end is connected to the second end of the first resistor R1, the second end of the second resistor R2 is connected to the negative terminal of the photovoltaic module 11 through the second control switch K2, and the second end of the second resistor R2 is also connected to the positive terminal of the photovoltaic module 11 through the fourth control switch K4; the resistance value of the first resistor R1 is greater than the resistance value of the second resistor R2.

[0133] The control module 15 is connected to the first control switch K1, the second control switch K2, the third control switch K3 and the fourth control switch K4 respectively, so as to control the switching action of the first control switch, the second control switch, the third control switch and the fourth control switch.

[0134] This embodiment also provides a heating system that utilizes the aforementioned photovoltaic power generation system. Specifically, refer to the heating system described in Embodiment 1.

[0135] The following combination Figure 5 The heating control method process of the heating system in this embodiment is described below:

[0136] Step b1: In the initial state, when the photovoltaic module has no output, the first control switch K1 (normally closed switch), the second control switch K2 (normally closed switch), the third control switch K3 (normally open switch), and the fourth control switch K4 (normally open switch) are all inactive, and the first resistor R1 (heating resistor) and the second resistor R2 (heating resistor) are connected in series to the circuit.

[0137] Step b2: As the ambient light around the photovoltaic module increases, the output voltage of the photovoltaic module begins to rise. When the output voltage of the photovoltaic module reaches the minimum input voltage requirement of the voltage regulator module, the voltage output by the voltage regulator module enables the logic judgment and control circuit to start working normally.

[0138] Step b3: The voltage detection module determines whether to output an action signal by detecting the output voltage Us of the photovoltaic module.

[0139] When the output voltage of the photovoltaic module continues to rise, and the output voltage Us of the photovoltaic module approaches the Um value of the saturation range, the first action voltage value of the voltage detection module is reached. At this time, the voltage detection module outputs an action signal to the delay module. After receiving the action signal, the delay module sends a control signal to the control circuit of the third control switch K3 after a delay of time t1, causing the third control switch K3 to close, thereby short-circuiting the second resistor R2. At this time, only the first resistor R1 is connected to the main circuit.

[0140] When the output voltage of the photovoltaic module continues to rise, and the output voltage Us of the photovoltaic module approaches the saturation value Um again, the second action voltage value of the voltage detection module is reached. At this time, the voltage detection module outputs an action signal to the delay module. After receiving the action signal, the delay module sends a control signal to the control circuit of the first control switch K1, the second control switch K2, the third control switch K3, and the fourth control switch K4 after a delay of t3. This causes all four control switches to operate, thereby disconnecting the first resistor R1. At this time, only the second resistor R2 is connected to the circuit.

[0141] When the output voltage of the photovoltaic module continues to rise, and the output voltage Us of the photovoltaic module approaches the Um value of the saturation range again, the third action voltage value of the voltage detection module is reached. At this time, the voltage detection module outputs an action signal to the delay module. After receiving the action signal, the delay module sends a control signal to the control loop of the first control switch K1, the second control switch K2, the third control switch K3, and the fourth control switch K4 after a delay of t5. This keeps the second control switch K2, the third control switch K3, and the fourth control switch K4 in the active state, and the first control switch K1 returns to closed, thereby connecting the first resistor R1 and the second resistor R2 in parallel to the main circuit.

[0142] When the output voltage of the photovoltaic module decreases, the output voltage Us of the photovoltaic module reaches the third return voltage value of the voltage detection module. At this time, the voltage detection module outputs an action signal and returns. After a delay of t6, it sends a control signal to the control circuit of the first control switch K1, the second control switch K2, the third control switch K3 and the fourth control switch K4, so that all four control switches are activated, thereby disconnecting the first resistor R1. At this time, only the second resistor R2 is connected to the circuit.

[0143] When the output voltage of the photovoltaic module decreases, the output voltage Us of the photovoltaic module reaches the second return voltage value of the voltage detection module. At this time, the voltage detection module outputs an action signal and returns. After a delay of t4, it sends a control signal to the control loop of the first control switch K1, the second control switch K2, the third control switch K3, and the fourth control switch K4, causing the first control switch K1, the second control switch K2, and the fourth control switch K4 to return, and the third control switch K3 to activate, thereby connecting the first resistor R1 to the circuit and short-circuiting the second resistor R2.

[0144] When the output voltage of the photovoltaic module continues to decrease, the output voltage Us of the photovoltaic module reaches the first return voltage value of the voltage detection module. At this time, the voltage detection module outputs an action signal and returns. After a delay of t2, the control signal is sent to the control loop of the first control switch K1, the second control switch K2, the third control switch K3 and the fourth control switch K4, so that the four control switches do not operate. The first resistor R1 and the second resistor R2 are connected in series in the circuit.

[0145] Step b4: At any time, when the temperature detection device detects that the water temperature in the energy storage device has reached the preset upper limit temperature value, the control module outputs an action signal and sends the control signal to the control circuit of the first control switch K1, the second control switch K2, the third control switch K3, and the fourth control switch K4 without delay, so that the first control switch K1 and the second control switch K2 are activated and the third control switch K3 and the fourth control switch K4 are deactivated, thus cutting off the main circuit; at this time, both the first resistor R1 and the second resistor R2 are not working.

[0146] When the temperature detection device detects that the water temperature in the energy storage device has dropped to the preset lower limit temperature value, the action signal output by the temperature detection device is returned, and the control signal is sent to the control circuit of the first control switch K1, the second control switch K2, the third control switch K3 and the fourth control switch K4 without delay, so that the four control switches act according to the logic output results of steps b1 to b3, and the first resistor R1 and the second resistor R2 work according to the logic control results.

[0147] Among them, the second control switch K2 and the fourth control switch K4 must be interlocked to ensure that only one of the two switches (K2 and K4) can be closed at the same time; otherwise, the output of the photovoltaic module will be short-circuited.

[0148] Although the preferred embodiments of the present invention have been described in detail above, it should be clearly understood that various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A photovoltaic power generation system, characterized in that, include: A photovoltaic module (11) is configured to convert solar energy into electrical energy; The voltage detection module (12) is connected to the voltage output terminal of the photovoltaic module (11) and is configured to detect the output voltage of the photovoltaic module; A voltage regulator module (13) has its input terminal connected to the voltage output terminal of the photovoltaic module (11); The load impedance module (14), connected to the voltage output terminal of the photovoltaic module (11), is configured to perform impedance operation or not after being controlled and to adjust its own impedance when performing impedance operation; The control module (15) is connected to the voltage detection module (12), the regulated power supply module (13), and the load impedance module (14), respectively.

2. The photovoltaic power generation system according to claim 1, characterized in that, The load impedance module (14) includes a first resistor (R1), a second resistor (R2), a first control switch (K1), and a second control switch (K2); wherein: A first resistor (R1) is configured such that its first terminal is connected to the positive terminal of the photovoltaic module (11) via a first control switch (K1), and its second terminal is connected to the negative terminal of the photovoltaic module (11); wherein the positive terminal of the photovoltaic module is the voltage output terminal of the photovoltaic module. The second resistor (R2) is configured such that its first end is connected to the positive terminal of the photovoltaic module (11) via the second control switch (K2), and its second end is connected to the negative terminal of the photovoltaic module (11); wherein the second resistor (R2) and the first resistor (R1) are connected in parallel, and the resistance value of the first resistor (R1) is greater than the resistance value of the second resistor (R2). The control module (15) is connected to the first control switch (K1) and the second control switch (K2) respectively to control the switching action of the first control switch and the switching action of the second control switch.

3. The photovoltaic power generation system according to claim 1, characterized in that, The load impedance module (14) includes a first resistor (R1), a second resistor (R2), a first control switch (K1), a second control switch (K2), and a third control switch (K3); wherein: The first resistor (R1) is configured such that its first terminal is connected to the positive terminal of the photovoltaic module (11) via the third control switch (K3); wherein the positive terminal of the photovoltaic module is the voltage output terminal of the photovoltaic module. The first control switch (K1) is connected in parallel across the first resistor (R1); The second resistor (R2) is configured such that its first end is connected to the second end of the first resistor (R1), and the second end of the second resistor (R2) is connected to the negative terminal of the photovoltaic module (11); wherein the resistance value of the first resistor (R1) is greater than the resistance value of the second resistor (R2). The second control switch (K2) is connected in parallel across the two ends of the second resistor (R2), and the second control switch (K2) is connected in series with the first control switch (K1); The control module (15) is connected to the first control switch (K1), the second control switch (K2) and the third control switch (K3) respectively, so as to control the switching action of the first control switch, the switching action of the second control switch and the switching action of the third control switch.

4. The photovoltaic power generation system according to claim 1, characterized in that, The load impedance module (14) includes a first resistor (R1), a second resistor (R2), a first control switch (K1), a second control switch (K2), a third control switch (K3), and a fourth control switch (K4); wherein: A first resistor (R1) is configured such that its first terminal is connected to the positive terminal of the photovoltaic module (11) via a first control switch (K1), and its second terminal is connected to the negative terminal of the photovoltaic module (11) via a third control switch (K3); wherein the positive terminal of the photovoltaic module is the voltage output terminal of the photovoltaic module. The second resistor (R2) is configured such that its first end is connected to the second end of the first resistor (R1), the second end of the second resistor (R2) is connected to the negative terminal of the photovoltaic module (11) through the second control switch (K2), and the second end of the second resistor (R2) is also connected to the positive terminal of the photovoltaic module (11) through the fourth control switch (K4); the resistance value of the first resistor (R1) is greater than the resistance value of the second resistor (R2); The control module (15) is connected to the first control switch (K1), the second control switch (K2), the third control switch (K3) and the fourth control switch (K4) respectively, so as to control the switching action of the first control switch, the second control switch, the third control switch and the fourth control switch.

5. The photovoltaic power generation system according to any one of claims 2 to 4, characterized in that, It also includes a delay module, the input of which is connected to the instruction output of the control module (15), and the output of which is connected to the first control switch (K1) and the second control switch (K2).

6. The photovoltaic power generation system according to claim 5, characterized in that, The voltage detection module (12) includes a diode (D), a current-limiting resistor (R), and a voltage-stabilizing capacitor (C) connected in series. The positive terminal of the diode (D) is connected to the positive terminal of the photovoltaic module (11), and the negative terminal of the diode (D) is connected to the first terminal of the voltage-stabilizing capacitor (C) through the current-limiting resistor (R). The second terminal of the voltage-stabilizing capacitor (C) is connected to the negative terminal of the photovoltaic module (11).

7. The photovoltaic power generation system according to claim 6, characterized in that, The voltage detection module (12) is connected to the positive terminal of the photovoltaic module (11) through a DC circuit breaker (QF), and the first terminal of the current limiting resistor (R) and the second terminal of the voltage stabilizing capacitor (C) are respectively connected to the control module (15).

8. A heating system, including an energy storage device containing a water medium, characterized in that, The application is a photovoltaic power generation system as described in any one of claims 1 to 7.

9. The heating system according to claim 8, characterized in that, Also includes: A heating device (21) is provided in the energy storage device (20) to heat the water medium in the energy storage device (20); Temperature detection device (22) is configured to detect the temperature of the water medium in the energy storage device (20).

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