Circuit for controlling MPPT (Maximum Power Point Tracking) photovoltaic inverter hot water system and hot water system

Abstract

The utility model is applicable to the technical field of photovoltaic conversion, and provides a circuit for controlling an MPPT (maximum power point tracking) photovoltaic inversion hot water system and the hot water system, the circuit comprises a photovoltaic module, a mains supply module, an MPPT inversion control module, a heating module and an interaction module, the photovoltaic module is used for converting light energy into electric energy and outputting direct-current voltage; the commercial power module is used for outputting a first AC voltage. The MPPT inversion control module is used for selecting the photovoltaic module or the commercial power module for connection, inverting a DC voltage output by the photovoltaic module into a second AC voltage, adjusting the second AC voltage in real time, outputting a first / second AC voltage, and receiving interaction data of the interaction module; the heating module is used for achieving the heating function of the hot water system. And the interaction module is used for sending interaction data of a user and the circuit for controlling the MPPT photovoltaic inverter hot water system. According to the utility model, the problem of large electric energy loss in the photovoltaic power supply process is solved.

Description

Technical Field

[0001] This utility model belongs to the field of photovoltaic conversion technology, and in particular relates to a control circuit for an MPPT photovoltaic inverter hot water system and a hot water system. Background Technology

[0002] A photovoltaic (PV) water heater, also known as a solar water heater, is a device that converts solar energy into heat energy to meet the hot water needs of households or businesses. The traditional working principle of a PV water heater is to use sunlight to irradiate a solar collector, transferring heat to the water inside the collector, raising the water temperature, and then storing the heated water in an insulated tank for user use.

[0003] Currently, there is a type of photovoltaic water heater that first stores the direct current (DC) from the photovoltaic panel into an energy storage device, then outputs stable DC power from the energy storage device, and finally inverts the DC power output from the energy storage device into alternating current (AC) to power the PTC heating element, thereby realizing the heating function of the water heater.

[0004] This requires energy storage devices as an intermediate medium, and the energy storage devices will also cause energy loss during the process of storing and converting electrical energy, resulting in a large energy loss problem in the process of photovoltaic power supply. Utility Model Content

[0005] The purpose of this utility model embodiment is to provide a control circuit for an MPPT photovoltaic inverter hot water system, which aims to solve the problem of large power loss during photovoltaic power supply.

[0006] This utility model embodiment is implemented as follows: a control circuit for an MPPT photovoltaic inverter hot water system, the control circuit for the MPPT photovoltaic inverter hot water system includes: a photovoltaic module, a mains power module, an MPPT inverter control module, a heating module, and an interactive module;

[0007] The photovoltaic module is connected to the MPPT inverter control module and is used to convert light energy into electrical energy and output DC voltage to the MPPT inverter control module.

[0008] The mains power module is connected to the MPPT inverter control module and is used to output a first AC voltage to the MPPT inverter control module;

[0009] The MPPT inverter control module is connected to the heating module and the interaction module. It is used to select the photovoltaic module or the mains module to connect to based on the DC voltage output by the photovoltaic module, invert the DC voltage output by the photovoltaic module into a second AC voltage and adjust the second AC voltage in real time according to the DC voltage and DC current output by the photovoltaic module, output a first / second AC voltage to the heating module, receive interactive data from the interaction module and select the photovoltaic module or the mains module to connect according to the interactive data.

[0010] The heating module is used to realize the heating function of the hot water system;

[0011] The interactive module is used to send interactive data between the user and the control circuit of the MPPT photovoltaic inverter hot water system to the MPPT inverter control module.

[0012] Preferably, the photovoltaic module includes: a photovoltaic panel, a surge protector, and a DC circuit breaker;

[0013] The output terminal of the photovoltaic panel is connected to one end of the surge protector;

[0014] The end of the surge protector that is not connected to the output terminal of the photovoltaic panel is connected to one end of the DC circuit breaker.

[0015] The end of the DC circuit breaker that is not connected to the surge protector is connected to one end of the MPPT inverter control module.

[0016] Preferably, the mains power module includes: an AC circuit breaker, a residual current device (RCD), and a power switch;

[0017] The output terminal of the AC circuit breaker is connected to the AC output interface, and the output terminal is connected to one end of the leakage current switch.

[0018] The end of the residual current device that is not connected to the output terminal of the AC circuit breaker is connected to one end of the power switch.

[0019] The end of the power switch that is not connected to the leakage current switch is connected to one end of the MPPT inverter control module.

[0020] Preferably, the MPPT inverter control module includes an MCU module, an MPPT inverter module, and a switching module;

[0021] The MCU module is connected to the MPPT inverter module, the switching module, and the interaction module. It is used to send a switching signal to the switching module according to the DC voltage output by the photovoltaic module, send an adjustment signal to the MPPT inverter module according to the DC voltage and DC current output by the photovoltaic module, and receive interactive data between the user and the control circuit of the MPPT photovoltaic inverter hot water system sent by the interaction module.

[0022] The MPPT inverter module is connected to the photovoltaic module and the switching module, and is used to invert the DC voltage output by the photovoltaic module into a second AC voltage and adjust the second AC voltage in real time according to the adjustment signal sent by the MCU module.

[0023] The switching module is connected to the mains power module and the heating module, and is used to select the photovoltaic module or the mains power module to connect to according to the switching signal sent by the MCU module, and output a first / second AC voltage to the heating module.

[0024] Preferably, the MCU module includes chip U7, chip U12, chip U13, resistor 24, resistor R25, resistor R26, resistor R27, resistor R1 and resistor R3;

[0025] The TIM3_CH2 interface of chip U7 is connected to the LIN interface of chip U12 through resistor R24, the TIM1_CH1 interface is connected to the HIN interface of chip U12 through resistor R25, the TIM3_CH3 interface is connected to the LIN interface of chip U13 through resistor R26, the TIM1_CH2 interface is connected to the HIN interface of chip U13 through resistor R27, and the first IO interface is connected to the switching module.

[0026] The LO and HO interfaces of the chip U12 are connected to the MPPT inverter module, and the VS interface is connected to the MPPT inverter module through the resistor R1.

[0027] The LO and HO interfaces of the chip U13 are connected to the MPPT inverter module, and the VS interface is connected to the MPPT inverter module through the resistor R3.

[0028] Preferably, the MPPT inverter module includes: MOSFET Q1, MOSFET Q2, MOSFET Q3, MOSFET Q4, resistor R90, resistor R91, resistor R92, resistor R93 and resistor R94;

[0029] The drain (D) of the MOSFET Q1 is connected to the positive terminal of the photovoltaic module, the gate (G) is connected to the HO interface of the chip U12 through the resistor R90, the source (S) is connected to the switching module, and the source (S) is connected to the VS interface of the chip U12 through the resistor R1.

[0030] The drain (D) of the MOSFET Q2 is connected to the positive terminal of the photovoltaic module, the gate (G) is connected to the HO interface of the chip U13 through the resistor R91, the source (S) is connected to the switching module, and the source (S) is connected to the VS interface of the chip U13 through the resistor R3.

[0031] The source (S) terminal of the MOSFET Q3 is connected to the negative terminal of the photovoltaic module, the gate (G) terminal is connected to the LO interface of the chip U12 through the resistor R92, and the drain (D) terminal is connected to the source (S) terminal of the MOSFET Q1.

[0032] The source (S) terminal of the MOSFET Q4 is connected to the negative terminal of the photovoltaic module, the gate (G) terminal is connected to the LO interface of the chip U13 through the resistor R93, and the drain (D) terminal is connected to the source (S) terminal of the MOSFET Q2.

[0033] One end of the resistor R94 is connected to the source (S) terminal of the MOSFET Q1, and the other end is connected to the source (S) terminal of the MOSFET Q2.

[0034] Preferably, the switching module includes transistor Q5, transistor Q6, diode D7, diode D8, relay RLY1, relay RLY2, transformer T2, resistor R39, resistor R38 and resistor R81;

[0035] The base (b) of transistor Q5 is connected to the first I / O interface of chip U7 through resistor R39, the emitter (e) is connected to the negative terminal of photovoltaic module, and the collector (c) is connected to the positive terminal of diode D7.

[0036] The base (b) of transistor Q6 is connected to the first I / O interface of chip U7 through resistor R38, the emitter (e) is connected to the negative terminal of photovoltaic module, and the collector (c) is connected to the positive terminal of diode D8.

[0037] The negative terminal of diode D7 is connected to the output terminal of the voltage conversion module;

[0038] The negative terminal of diode D8 is connected to the output terminal of the voltage conversion module;

[0039] The positive terminal of the relay RLY1 is connected to the negative terminal of the diode D8, and the negative terminal is connected to the collector terminal of the transistor Q6. The first input terminal is connected to the inductor terminal of the mains module, the second input terminal is connected to the source terminal of the MOSFET Q2, and the output terminal is connected to the first interface of the input terminal of the transformer T2.

[0040] The positive terminal of the relay RLY2 is connected to the negative terminal of the diode D7, and the negative terminal is connected to the collector terminal of the transistor Q5. The first input terminal is connected to the N terminal of the mains power module, the second input terminal is connected to the source terminal of the MOSFET Q1, and the output terminal is connected to the heating module.

[0041] The second interface of the input terminal of the transformer T2 is connected to the heating module, and the first interface of the output terminal is connected to the second interface of the output terminal of the transformer T2 through the resistor R81.

[0042] Preferably, the heating module includes a heating element and a water temperature sensor;

[0043] The L end of the heating tube is connected to the second interface of the input terminal of the transformer T2, and the N end is connected to the output terminal of the relay RLY2, so as to realize the heating function of the hot water system.

[0044] The water temperature sensor is connected to the heating element and the MCU module, and is used to obtain the temperature of the heating element and send temperature data to the MCU module.

[0045] Preferably, the interactive module includes a communication module and a touch module;

[0046] The communication module is used to receive interactive data from the mobile terminal and send the interactive data from the mobile terminal to the MPPT inverter control module.

[0047] The touch module is used to generate interactive data between the user and the control circuit of the MPPT photovoltaic inverter hot water system based on the user's touch settings, and send the interactive data to the MPPT inverter control module.

[0048] Another objective of this utility model embodiment is a hot water system, which includes: a water tank and a heating device equipped with a control circuit for the MPPT photovoltaic inverter hot water system as described above.

[0049] This invention provides a control circuit for an MPPT photovoltaic inverter hot water system. The MPPT inverter control module selects either the photovoltaic module or the mains power module for connection based on the DC voltage output by the photovoltaic module. When the photovoltaic module is selected, the MPPT inverter control module inverts the DC voltage output by the photovoltaic module into a second AC voltage and adjusts the second AC voltage in real time according to the DC voltage and DC current output by the photovoltaic module. This second AC voltage is then output to the heating module to enable the heating function of the hot water system. This invention's MPPT inverter control module does not require an energy storage device as an intermediate medium. It can directly invert the DC voltage output by the photovoltaic module into a second AC voltage usable by the heating module. Simultaneously, during the inversion process, the real-time adjustment of the second AC voltage based on the DC voltage and DC current output by the photovoltaic module keeps the hot water system operating at its highest efficiency. By eliminating the need for energy storage and the real-time adjustment of the second AC voltage during energy conversion, the problem of significant energy loss during photovoltaic power supply is solved. Attached Figure Description

[0050] Figure 1 A structural diagram of a control circuit for an MPPT photovoltaic inverter hot water system provided in an embodiment of this utility model;

[0051] Figure 2 Circuit for MCU module Figure 1 ;

[0052] Figure 3 Circuit for MCU module Figure 2 ;

[0053] Figure 4 This is the circuit diagram of the MPPT inverter module;

[0054] Figure 5 This is the circuit diagram for the switching module. Detailed Implementation

[0055] To make the objectives, technical solutions, and advantages of this utility model clearer, the present utility model will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the present utility model and are not intended to limit the present utility model.

[0056] The specific implementation of this utility model will be described in detail below with reference to specific embodiments.

[0057] like Figure 1 The diagram shown is a structural diagram of a control circuit for an MPPT photovoltaic inverter hot water system provided in an embodiment of this utility model, comprising:

[0058] Photovoltaic module, mains power module, MPPT inverter control module, heating module, and interactive module;

[0059] The photovoltaic module is connected to the MPPT inverter control module and is used to convert light energy into electrical energy and output DC voltage to the MPPT inverter control module.

[0060] The mains power module is connected to the MPPT inverter control module and is used to output a first AC voltage to the MPPT inverter control module;

[0061] The MPPT inverter control module is connected to the heating module and the interaction module. It is used to select the photovoltaic module or the mains module to connect to based on the DC voltage output by the photovoltaic module, invert the DC voltage output by the photovoltaic module into a second AC voltage and adjust the second AC voltage in real time according to the DC voltage and DC current output by the photovoltaic module, output a first / second AC voltage to the heating module, receive interactive data from the interaction module and select the photovoltaic module or the mains module to connect according to the interactive data.

[0062] The heating module is used to realize the heating function of the hot water system;

[0063] The interactive module is used to send interactive data between the user and the control circuit of the MPPT photovoltaic inverter hot water system to the MPPT inverter control module.

[0064] In this embodiment of the invention, the first AC voltage output by the mains power module is a stable AC voltage and AC current, while the photovoltaic module outputs a changing DC voltage.

[0065] In this embodiment of the invention, selecting the photovoltaic module or the mains module for connection based on the DC voltage output by the photovoltaic module means that if the DC voltage output by the photovoltaic module is less than a preset voltage, then the mains module is selected to be connected to the MPPT inverter control module; if the DC voltage output by the photovoltaic module is greater than or equal to the preset voltage, then the photovoltaic module is selected to be connected to the MPPT inverter control module. The operating voltage of the heating module is AC voltage. The operating voltage of the heating module is rectified to DC voltage, and this DC voltage is the preset voltage. A common scenario is at night or on a cloudy day, when the DC voltage output by the photovoltaic module is less than the preset voltage. In this case, the mains module needs to output a first AC voltage to the heating module, i.e., the mains module is selected to be connected to the MPPT inverter control module.

[0066] In this embodiment of the invention, since the photovoltaic module outputs a changing DC voltage, the MPPT inverter control module inverts the DC voltage output by the photovoltaic module into a changing second AC voltage. Real-time adjustment of the second AC voltage based on the DC voltage and DC current output by the photovoltaic module refers to sampling the DC voltage and DC current output by the photovoltaic module and adjusting the second AC voltage in real time using the MPPT algorithm so that the obtained second AC voltage is obtained from the photovoltaic module at its highest output power, thus enabling the photovoltaic module to have higher power generation efficiency.

[0067] In this embodiment of the invention, the control circuit for the MPPT photovoltaic inverter hot water system may further include a storage battery, which is connected to the photovoltaic module and is used to store excess electrical energy generated by the photovoltaic module.

[0068] In this embodiment of the invention, the control circuit for the MPPT photovoltaic inverter hot water system further includes a voltage conversion module; the input terminal of the voltage conversion module is connected to the output terminal of the battery, and is used to convert the output voltage of the battery into the operating voltage of the chips and other components in the MPPT inverter control module. The battery can be a rechargeable battery or a disposable battery.

[0069] In this embodiment of the invention, the interactive data can be communication data from a mobile terminal such as a mobile phone, or setting data that the user makes via touch settings through internal devices such as a button module or touch module. Selecting the photovoltaic module or the mains power module for connection based on the interactive data means that the user selects to use either the photovoltaic module or the mains power module via a mobile phone or button module. The priority of selecting the photovoltaic module or the mains power module for connection based on interactive data is higher than selecting the photovoltaic module or the mains power module for connection based on the DC voltage output by the photovoltaic module.

[0070] This invention provides a control circuit for an MPPT photovoltaic inverter hot water system. The MPPT inverter control module selects either the photovoltaic module or the mains power module for connection based on the DC voltage output by the photovoltaic module. When the photovoltaic module is selected, the MPPT inverter control module inverts the DC voltage output by the photovoltaic module into a second AC voltage and adjusts the second AC voltage in real time according to the DC voltage and DC current output by the photovoltaic module. This second AC voltage is then output to the heating module to enable the heating function of the hot water system. This invention's MPPT inverter control module does not require an energy storage device as an intermediate medium. It can directly invert the DC voltage output by the photovoltaic module into a second AC voltage usable by the heating module. Simultaneously, during the inversion process, the second AC voltage is adjusted in real time according to the DC voltage and DC current output by the photovoltaic module, ensuring that the obtained second AC voltage is obtained at the highest output power of the photovoltaic module. This solves the problem of significant energy loss during photovoltaic power supply by subtracting the energy storage process and by adjusting the second AC voltage in real time during energy conversion.

[0071] like Figure 1 As shown, in a preferred embodiment of the present invention, the photovoltaic module includes: a photovoltaic panel, a surge protector, and a DC circuit breaker;

[0072] The output terminal of the photovoltaic panel is connected to one end of the surge protector;

[0073] The end of the surge protector that is not connected to the output terminal of the photovoltaic panel is connected to one end of the DC circuit breaker.

[0074] The end of the DC circuit breaker that is not connected to the surge protector is connected to one end of the MPPT inverter control module.

[0075] In this embodiment of the invention, the input end of the photovoltaic panel is a photosensitive surface that receives solar energy. The function of the photovoltaic panel is to convert solar energy into a DC voltage, which is a variable voltage.

[0076] In this embodiment of the invention, the surge protector serves a protective function.

[0077] In this embodiment of the invention, the DC circuit breaker is normally closed. If the DC circuit breaker is open, the output voltage of the photovoltaic panel cannot be transmitted to the MPPT inverter control module.

[0078] In this embodiment of the invention, the output voltage of the photovoltaic panel is the DC voltage output by the photovoltaic module.

[0079] like Figure 1As shown, in a preferred embodiment of this utility model, the mains power module includes: an AC circuit breaker, a residual current device (RCD), and a power switch;

[0080] The input terminal of the AC circuit breaker is connected to the mains power, and the output terminal is connected to one end of the leakage current switch.

[0081] The end of the residual current device that is not connected to the output terminal of the AC circuit breaker is connected to one end of the power switch.

[0082] The end of the power switch that is not connected to the leakage current switch is connected to one end of the MPPT inverter control module.

[0083] In this embodiment of the utility model, the mains power is typically 220V AC.

[0084] In this embodiment of the invention, the leakage current switch serves a protective function.

[0085] In this embodiment of the invention, the AC circuit breaker and power switch are normally in the closed state. If the AC circuit breaker or power switch is in the open state, the mains power cannot be transmitted to the MPPT inverter control module.

[0086] like Figure 1 As shown, in a preferred embodiment of this utility model, the MPPT inverter control module includes an MCU module, an MPPT inverter module, and a switching module;

[0087] The MCU module is connected to the MPPT inverter module, the switching module, and the interaction module. It is used to send a switching signal to the switching module according to the DC voltage output by the photovoltaic module, send an adjustment signal to the MPPT inverter module according to the DC voltage and DC current output by the photovoltaic module, receive interactive data between the user and the control circuit of the MPPT photovoltaic inverter hot water system sent by the interaction module, and send a switching signal to the switching module according to the interactive data.

[0088] The MPPT inverter module is connected to the photovoltaic module and the switching module, and is used to invert the DC voltage output by the photovoltaic module into a second AC voltage and adjust the second AC voltage in real time according to the adjustment signal sent by the MCU module.

[0089] The switching module is connected to the mains power module and the heating module, and is used to select the photovoltaic module or the mains power module to connect to according to the switching signal sent by the MCU module, and output a first / second AC voltage to the heating module.

[0090] In this embodiment of the invention, the MCU module samples the DC voltage output by the photovoltaic module. The DC voltage output by the photovoltaic module is applied to the MPPT inverter module, and after being inverted into a second AC voltage, it is applied to the heating module. The first AC voltage from the mains power module is applied to the heating module.

[0091] like Figure 2 , Figure 3 As shown, in a preferred embodiment of the present invention, the MCU module includes chip U7, chip U12, chip U13, resistor 24, resistor R25, resistor R26, resistor R27, resistor R1 and resistor R3.

[0092] The TIM3_CH2 interface of chip U7 is connected to the LIN interface of chip U12 through resistor R24, the TIM1_CH1 interface is connected to the HIN interface of chip U12 through resistor R25, the TIM3_CH3 interface is connected to the LIN interface of chip U13 through resistor R26, the TIM1_CH2 interface is connected to the HIN interface of chip U13 through resistor R27, and the first IO interface is connected to the switching module.

[0093] The LO and HO interfaces of the chip U12 are connected to the MPPT inverter module, and the VS interface is connected to the MPPT inverter module through the resistor R1.

[0094] The LO and HO interfaces of the chip U13 are connected to the MPPT inverter module, and the VS interface is connected to the MPPT inverter module through the resistor R3.

[0095] In this embodiment of the invention, the switching signal is sent by the first IO interface, and the switching signal sent by the first IO interface is a high-level or low-level signal. The adjustment signal is sent by the LO and HO interfaces of chip U12 and the LO and HO interfaces of chip U13, and the adjustment signal sent by these four interfaces is a high-level or low-level signal.

[0096] In this embodiment of the invention, chip U7 can sample the DC voltage output by the photovoltaic module through an ADC interface, for example... Figure 2 The ADC_IN11 interface in [the context of the application].

[0097] In this embodiment of the invention, the TIM3_CH2, TIM1_CH1, TIM3_CH3, and TIM1_CH2 interfaces are output interfaces of the advanced timer, used for PWM output. However, these four interfaces are not strictly necessary for connection; any data interface of the advanced timer can be used to replace them.

[0098] In this embodiment of the utility model, chip U12 and chip U13 are the same type of chip, which is a MOS driver IC.

[0099] In this embodiment of the invention, the conventional interfaces such as the power interface and ground interface in chips U7, U12, and U13 can be connected according to existing technology. For example, the power interface is connected to the output terminal of the voltage conversion module, and the ground interface is connected to the ground wire. The voltage conversion module can have multiple output terminals and can output various DC voltage specifications, such as 12V, 5V, etc.

[0100] like Figure 4 As shown, in a preferred embodiment of the present invention, the MPPT inverter module includes: MOSFET Q1, MOSFET Q2, MOSFET Q3, MOSFET Q4, resistor R90, resistor R91, resistor R92, resistor R93 and resistor R94;

[0101] The drain (D) of the MOSFET Q1 is connected to the positive terminal of the photovoltaic module, the gate (G) is connected to the HO interface of the chip U12 through the resistor R90, the source (S) is connected to the switching module, and the source (S) is connected to the VS interface of the chip U12 through the resistor R1.

[0102] The drain (D) of the MOSFET Q2 is connected to the positive terminal of the photovoltaic module, the gate (G) is connected to the HO interface of the chip U13 through the resistor R91, the source (S) is connected to the switching module, and the source (S) is connected to the VS interface of the chip U13 through the resistor R3.

[0103] The source (S) terminal of the MOSFET Q3 is connected to the negative terminal of the photovoltaic module, the gate (G) terminal is connected to the LO interface of the chip U12 through the resistor R92, and the drain (D) terminal is connected to the source (S) terminal of the MOSFET Q1.

[0104] The source (S) terminal of the MOSFET Q4 is connected to the negative terminal of the photovoltaic module, the gate (G) terminal is connected to the LO interface of the chip U13 through the resistor R93, and the drain (D) terminal is connected to the source (S) terminal of the MOSFET Q2.

[0105] One end of the resistor R94 is connected to the source (S) terminal of the MOSFET Q1, and the other end is connected to the source (S) terminal of the MOSFET Q2.

[0106] In the embodiments of this utility model, such as Figure 4 As shown, the positive terminal of the photovoltaic module is PV+, and the negative terminal is PV2-. The negative terminal of the photovoltaic module is generally connected to the ground wire.

[0107] In this embodiment of the invention, the MPPT inverter module further includes diodes D9, D10, D11, and D12. Diode D9 is connected in parallel across resistor R90, with its anode connected to the gate (G) of MOSFET Q1; diode D11 is connected in parallel across resistor R91, with its anode connected to the gate (G) of MOSFET Q2; diode D10 is connected in parallel across resistor R92, with its anode connected to the gate (G) of MOSFET Q3; and diode D13 is connected in parallel across resistor R93, with its anode connected to the gate (G) of MOSFET Q4.

[0108] In this embodiment of the invention, MOSFETs Q1, Q2, Q3, and Q4 form an H-bridge. By driving the four MOSFETs (Q1, Q2, Q3, and Q4) on the H-bridge, the DC voltage output by the photovoltaic module is inverted into a second AC voltage. The signal driving the H-bridge is an adjustment signal sent by the MCU module. For example, if MOSFETs Q1 and Q4 are simultaneously turned on, the current flows from the positive terminal of the photovoltaic module into the drain (D) of MOSFET Q1 and then through resistor R94 from the drain (D) of MOSFET Q4 to the source (S) of MOSFET Q4 and out to the negative terminal of the photovoltaic module. At this time, the voltage at point AH is the positive AC voltage, and the voltage at point BH is the negative AC voltage. If MOSFETs Q2 and Q3 are turned on, the voltage at point AH is the negative AC voltage, and the voltage at point BH is the positive AC voltage. This enables the DC voltage output by the photovoltaic module to be inverted into a second AC voltage.

[0109] In this embodiment of the invention, real-time adjustment of the second AC voltage essentially involves adjusting the duty cycle of the PWM signals output to the gates (G) of MOSFETs Q1, Q2, Q3, and Q4. The duty cycle is determined by the TIM3_CH2, TIM1_CH1, TIM3_CH3, and TIM1_CH2 interfaces of chip U7. The outputs of these interfaces are determined by chip U7 based on the DC voltage and current output from the photovoltaic module. Therefore, the second AC voltage is adjusted in real-time according to the DC voltage and current output from the photovoltaic module.

[0110] like Figure 5 As shown, in a preferred embodiment of this utility model, the switching module includes transistor Q5, transistor Q6, diode D7, diode D8, relay RLY1, relay RLY2, transformer T2, resistor R39, resistor R38 and resistor R81;

[0111] The base (b) of transistor Q5 is connected to the first I / O interface of chip U7 through resistor R39, the emitter (e) is connected to the negative terminal of photovoltaic module, and the collector (c) is connected to the positive terminal of diode D7.

[0112] The base (b) of transistor Q6 is connected to the first I / O interface of chip U7 through resistor R38, the emitter (e) is connected to the negative terminal of photovoltaic module, and the collector (c) is connected to the positive terminal of diode D8.

[0113] The negative terminal of diode D7 is connected to the output terminal of the voltage conversion module;

[0114] The negative terminal of diode D8 is connected to the output terminal of the voltage conversion module;

[0115] The positive terminal of the relay RLY1 is connected to the negative terminal of the diode D8, and the negative terminal is connected to the collector terminal of the transistor Q6. The first input terminal is connected to the inductor terminal of the mains module, the second input terminal is connected to the source terminal of the MOSFET Q2, and the output terminal is connected to the first interface of the input terminal of the transformer T2.

[0116] The positive terminal of the relay RLY2 is connected to the negative terminal of the diode D7, and the negative terminal is connected to the collector terminal of the transistor Q5. The first input terminal is connected to the N terminal of the mains power module, the second input terminal is connected to the source terminal of the MOSFET Q1, and the output terminal is connected to the heating module.

[0117] The second interface of the input terminal of the transformer T2 is connected to the heating module, and the first interface of the output terminal is connected to the second interface of the output terminal of the transformer T2 through the resistor R81.

[0118] In the embodiments of this utility model, such as Figure 5 As shown, the output of the voltage conversion module is 12V.

[0119] In this embodiment of the invention, when the first IO interface of chip U7 outputs a low level, transistors Q5 and Q6 are turned on. At this time, relay RLY2 is energized, connecting the first output terminal of relay RLY2 to the output terminal, i.e., the N terminal of the mains module is connected to the N terminal of the heating tube. Relay RLY1 is energized, connecting the first output terminal of relay RLY1 to the output terminal, i.e., the L terminal of the mains module is connected to the L terminal of the heating tube after passing through transformer T2, thereby providing a first AC voltage to the heating tube. When the first IO interface of chip U7 outputs a high level, transistors Q5 and Q6 are not turned on. Relay RLY2 is de-energized, connecting the second output terminal of relay RLY2 to the output terminal, i.e., the S terminal of MOSFET Q1 is connected to the N terminal of the heating tube. Relay RLY1 is energized, connecting the second output terminal of relay RLY1 to the output terminal, i.e., the S terminal of MOSFET Q2 is connected to the L terminal of the heating tube after passing through transformer T2, thereby providing a second AC voltage to the heating tube.

[0120] In this embodiment of the invention, transformer T2 and resistor R81 are used for detecting current and power when powered by mains electricity, ensuring that users can monitor real-time or cumulative power consumption on the APP. This step can be achieved by connecting the first and second interfaces of the output terminal of transformer T2 to the sampling circuit.

[0121] like Figure 1 As shown, in a preferred embodiment of this utility model, the heating module includes a heating tube and a water temperature sensor;

[0122] The L end of the heating tube is connected to the second interface of the input terminal of the transformer T2, and the N end is connected to the output terminal of the relay RLY2, so as to realize the heating function of the hot water system.

[0123] The water temperature sensor is connected to the heating element and the MCU module, and is used to obtain the temperature of the heating element and send temperature data to the MCU module.

[0124] In this embodiment of the invention, a multi-position toggle switch and several resistors may be provided between the circuit connecting the L end of the heating tube and the second interface of the input terminal of the transformer T2, for controlling the opening, closing and adjustment of the heating function.

[0125] like Figure 1 As shown, in a preferred embodiment of this utility model, the interactive module includes a communication module and a touch module;

[0126] The communication module is used to receive interactive data from the mobile terminal and send the interactive data from the mobile terminal to the MPPT inverter control module.

[0127] The touch module is used to generate interactive data between the user and the control circuit of the MPPT photovoltaic inverter hot water system based on the user's touch settings, and send the interactive data to the MPPT inverter control module.

[0128] In this embodiment of the invention, the mobile terminal can be a mobile phone, remote control, tablet, or other device with communication capabilities. The touch module includes a display screen, buttons, and other devices that are wiredly connected to the MCU module in the MPPT inverter control module.

[0129] In this embodiment of the invention, the chip U7 in the MCU module of the MPPT inverter control module can interact with the communication module through the RX interface and the TX interface, and can interact with the touch module through any IO interface.

[0130] In this embodiment of the invention, the interactive data received from the mobile terminal is communication data, and the interactive data generated between the user and the control circuit of the MPPT photovoltaic inverter hot water system based on the user's touch settings is setting data.

[0131] This utility model embodiment also provides a hot water system, which includes: a water tank and a heating device equipped with a control circuit for the MPPT photovoltaic inverter hot water system as described above.

[0132] In this embodiment of the invention, only the heating module contacts the water tank and the heating device of the MPPT photovoltaic inverter hot water system control circuit.

[0133] This utility model provides a hot water system that uses an MPPT inverter control module to select either a photovoltaic module or a mains power module for connection based on the DC voltage output by the photovoltaic module. When the photovoltaic module is selected, the MPPT inverter control module inverts the DC voltage output by the photovoltaic module into a second AC voltage and adjusts the second AC voltage in real time according to the DC voltage and DC current output by the photovoltaic module, outputting the second AC voltage to the heating module to enable the heating module to perform the heating function of the hot water system. This utility model's MPPT inverter control module does not require an energy storage device as an intermediate medium; it can directly invert the DC voltage output by the photovoltaic module into a second AC voltage usable by the heating module. Simultaneously, during the inversion process, the second AC voltage is adjusted in real time according to the DC voltage and DC current output by the photovoltaic module, ensuring that the obtained second AC voltage is obtained from the photovoltaic module at its maximum output power. This solves the problem of significant energy loss during photovoltaic power supply by subtracting the energy storage process and by adjusting the second AC voltage in real time during energy conversion.

[0134] The above description is only a preferred embodiment of the present utility model and is not intended to limit the present utility model. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present utility model should be included within the protection scope of the present utility model.

Claims

1. A control circuit for an MPPT photovoltaic inverter hot water system, characterized in that, The control circuit for the MPPT photovoltaic inverter hot water system includes: a photovoltaic module, a mains power module, an MPPT inverter control module, a heating module, and an interactive module; The photovoltaic module is connected to the MPPT inverter control module and is used to convert light energy into electrical energy and output DC voltage to the MPPT inverter control module. The mains power module is connected to the MPPT inverter control module and is used to output a first AC voltage to the MPPT inverter control module; The MPPT inverter control module is connected to the heating module and the interaction module. It is used to select the photovoltaic module or the mains module to connect to based on the DC voltage output by the photovoltaic module, invert the DC voltage output by the photovoltaic module into a second AC voltage and adjust the second AC voltage in real time according to the DC voltage and DC current output by the photovoltaic module, output a first / second AC voltage to the heating module, receive interactive data from the interaction module and select the photovoltaic module or the mains module to connect according to the interactive data. The heating module is used to realize the heating function of the hot water system; The interactive module is used to send interactive data between the user and the control circuit of the MPPT photovoltaic inverter hot water system to the MPPT inverter control module.

2. The MPPT photovoltaic inverter water heating system control circuit according to claim 1, wherein, The photovoltaic module includes: a photovoltaic panel, a surge protector, and a DC circuit breaker; The output terminal of the photovoltaic panel is connected to one end of the surge protector; The end of the surge protector that is not connected to the output terminal of the photovoltaic panel is connected to one end of the DC circuit breaker. The end of the DC circuit breaker that is not connected to the surge protector is connected to one end of the MPPT inverter control module.

3. The MPPT photovoltaic inverter water heating system control circuit according to claim 1, wherein, The mains power module includes: an AC circuit breaker, a residual current device (RCD), and a power switch; The input terminal of the AC circuit breaker is connected to the mains power, and the output terminal is connected to one end of the leakage current switch. The end of the residual current device that is not connected to the output terminal of the AC circuit breaker is connected to one end of the power switch. The end of the power switch that is not connected to the leakage current switch is connected to one end of the MPPT inverter control module.

4. The MPPT photovoltaic inverter water heating system control circuit according to claim 1, wherein, The MPPT inverter control module includes an MCU module, an MPPT inverter module, and a switching module; The MCU module is connected to the MPPT inverter module, the switching module, and the interaction module. It is used to send a switching signal to the switching module according to the DC voltage output by the photovoltaic module, send an adjustment signal to the MPPT inverter module according to the DC voltage and DC current output by the photovoltaic module, receive interactive data between the user and the control circuit of the MPPT photovoltaic inverter hot water system sent by the interaction module, and send a switching signal to the switching module according to the interactive data. The MPPT inverter module is connected to the photovoltaic module and the switching module, and is used to invert the DC voltage output by the photovoltaic module into a second AC voltage and adjust the second AC voltage in real time according to the adjustment signal sent by the MCU module. The switching module is connected to the mains power module and the heating module, and is used to select the photovoltaic module or the mains power module to connect to according to the switching signal sent by the MCU module, and output a first / second AC voltage to the heating module.

5. The MPPT photovoltaic inverter water heating system control circuit according to claim 4, wherein, The MCU module includes chip U7, chip U12, chip U13, resistor R24, resistor R25, resistor R26, resistor R27, resistor R1 and resistor R3; The TIM3_CH2 interface of chip U7 is connected to the LIN interface of chip U12 through resistor R24, the TIM1_CH1 interface is connected to the HIN interface of chip U12 through resistor R25, the TIM3_CH3 interface is connected to the LIN interface of chip U13 through resistor R26, the TIM1_CH2 interface is connected to the HIN interface of chip U13 through resistor R27, and the first IO interface is connected to the switching module. The LO and HO interfaces of the chip U12 are connected to the MPPT inverter module, and the VS interface is connected to the MPPT inverter module through the resistor R1. The LO and HO interfaces of the chip U13 are connected to the MPPT inverter module, and the VS interface is connected to the MPPT inverter module through the resistor R3.

6. The MPPT photovoltaic inverter water heating system control circuit according to claim 5, wherein, The MPPT inverter module includes: MOSFET Q1, MOSFET Q2, MOSFET Q3, MOSFET Q4, resistor R90, resistor R91, resistor R92, resistor R93 and resistor R94; The drain (D) of the MOSFET Q1 is connected to the positive terminal of the photovoltaic module, the gate (G) is connected to the HO interface of the chip U12 through the resistor R90, the source (S) is connected to the switching module, and the source (S) is connected to the VS interface of the chip U12 through the resistor R1. The drain (D) of the MOSFET Q2 is connected to the positive terminal of the photovoltaic module, the gate (G) is connected to the HO interface of the chip U13 through the resistor R91, the source (S) is connected to the switching module, and the source (S) is connected to the VS interface of the chip U13 through the resistor R3. The source (S) terminal of the MOSFET Q3 is connected to the negative terminal of the photovoltaic module, the gate (G) terminal is connected to the LO interface of the chip U12 through the resistor R92, and the drain (D) terminal is connected to the source (S) terminal of the MOSFET Q1. The source (S) terminal of the MOSFET Q4 is connected to the negative terminal of the photovoltaic module, the gate (G) terminal is connected to the LO interface of the chip U13 through the resistor R93, and the drain (D) terminal is connected to the source (S) terminal of the MOSFET Q2. One end of the resistor R94 is connected to the source (S) terminal of the MOSFET Q1, and the other end is connected to the source (S) terminal of the MOSFET Q2.

7. The MPPT photovoltaic inverter water heating system control circuit according to claim 6, wherein, The switching module includes transistor Q5, transistor Q6, diode D7, diode D8, relay RLY1, relay RLY2, transformer T2, resistor R39, resistor R38 and resistor R81; The base (b) of transistor Q5 is connected to the first I / O interface of chip U7 through resistor R39, the emitter (e) is connected to the negative terminal of photovoltaic module, and the collector (c) is connected to the positive terminal of diode D7. The base (b) of transistor Q6 is connected to the first I / O interface of chip U7 through resistor R38, the emitter (e) is connected to the negative terminal of photovoltaic module, and the collector (c) is connected to the positive terminal of diode D8. The negative terminal of diode D7 is connected to the output terminal of the voltage conversion module; The negative terminal of diode D8 is connected to the output terminal of the voltage conversion module; The positive terminal of the relay RLY1 is connected to the negative terminal of the diode D8, and the negative terminal is connected to the collector terminal of the transistor Q6. The first input terminal is connected to the inductor terminal of the mains module, the second input terminal is connected to the source terminal of the MOSFET Q2, and the output terminal is connected to the first interface of the input terminal of the transformer T2. The positive terminal of the relay RLY2 is connected to the negative terminal of the diode D7, and the negative terminal is connected to the collector terminal of the transistor Q5. The first input terminal is connected to the N terminal of the mains power module, the second input terminal is connected to the source terminal of the MOSFET Q1, and the output terminal is connected to the heating module. The second interface of the input terminal of the transformer T2 is connected to the heating module, and the first interface of the output terminal is connected to the second interface of the output terminal of the transformer T2 through the resistor R81.

8. The control circuit for the MPPT photovoltaic inverter hot water system according to claim 7, characterized in that, The heating module includes a heating element and a water temperature sensor; The L end of the heating tube is connected to the second interface of the input terminal of the transformer T2, and the N end is connected to the output terminal of the relay RLY2, so as to realize the heating function of the hot water system. The water temperature sensor is connected to the heating element and the MCU module, and is used to obtain the temperature of the heating element and send temperature data to the MCU module.

9. The control circuit for the MPPT photovoltaic inverter hot water system according to claim 1, characterized in that, The interactive module includes a communication module and a touch module; The communication module is used to receive interactive data from the mobile terminal and send the interactive data from the mobile terminal to the MPPT inverter control module. The touch module is used to generate interactive data between the user and the control circuit of the MPPT photovoltaic inverter hot water system based on the user's touch settings, and send the interactive data to the MPPT inverter control module.

10. A hot water system characterised by, The hot water system includes: a water tank and a heating device equipped with a control circuit for the MPPT photovoltaic inverter hot water system as described in any one of claims 1-9.

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