Solar photovoltaic water heater control assembly

Abstract

The utility model discloses a control assembly of a solar photovoltaic water heater, and relates to the field of solar photovoltaics. The solar photovoltaic water heater control assembly comprises an MCU control driving module, a photovoltaic panel electric energy optimal adaptation module, an anti-reverse connection module and an operation display panel module. According to the solar photovoltaic water heater control assembly, photovoltaic input and output, water tank temperature, output current and other information are detected through the MCU, the duty ratio is fed back and adjusted to the grid driving chip module, and the grid driving chip module outputs a duty ratio driving signal with a certain frequency according to the information of the mcu to drive the switching time of the power switching device module. Therefore, the output voltage is adjusted, photovoltaic solar optimal adaptive use is realized, and the utilization rate of the electric energy of the photovoltaic panel is improved.

Description

Technical Field

[0001] The utility model relates to the technical field of solar photovoltaic technology, in particular to a solar photovoltaic water heater control component. Background Art

[0002] A photovoltaic water heater is a water heater that converts solar energy into electrical energy and then uses the electrical energy to heat water.

[0003] Photovoltaic water heaters convert sunlight's photon energy into electrical energy through photovoltaic panel assemblies. When light hits the surface of the cell, the photons are absorbed by the semiconductor material, causing electron transitions and forming a potential difference, thereby generating current. The converted electrical energy is stored and controlled by a controller, and then transferred to the electric heater in the water heater to heat the water.

[0004] In the existing technology, photovoltaic water heaters can only work normally when there is AC power. The voltage generated by the AC power is used to drive the corresponding MOS tube, and the photovoltaic panel voltage and the DC heating tube form a loop. The DC heating tube works to heat. When the AC power is disconnected, the power switch tube is disconnected and the DC heating tube will not work, resulting in the photovoltaic panel power not being used to the maximum and optimal extent. Therefore, we propose a solar photovoltaic water heater control component. Utility Model Content

[0005] In response to the deficiencies of the existing technology, the utility model provides a solar photovoltaic water heater control component, which solves the problem that when the mains power is disconnected, the power switch tube is disconnected, the DC heating tube will not work, resulting in the photovoltaic panel power not being used to the maximum and optimal extent.

[0006] To achieve the above objectives, the present invention is implemented through the following technical solutions: A solar photovoltaic water heater control component, comprising:

[0007] MCU control drive module, photovoltaic panel power optimal adaptation module, anti-reverse connection module and operation display panel module,

[0008] The MCU control drive module includes AC control components and DC control components;

[0009] The photovoltaic panel power optimal adaptation module is provided with a hardware circuit DC-DC conversion circuit;

[0010] The hardware circuit DC-DC conversion circuit is provided with a MOSFET gate protection circuit, and a gate drive chip is installed on the MOSFET gate protection circuit.

[0011] Preferably, the MCU control drive module includes resistors R7, R46 and gate drive chips U1, ZD1, D3, C25, C4, C31, C3, and E1. One end of the resistors R7 and R46 are connected to the HO and LO pins of the MCU, E1 is a bootstrap capacitor, and ZD1 is a voltage regulator.

[0012] Preferably, the DC control component includes resistors R1, R16, resistors R6, R44, diodes D1, D16, power switches Q10, Q11, D41 and inductor L1.

[0013] Preferably, the DC control component includes its gate drive chip.

[0014] Preferably, the DC control component includes a power switch tube MOSFET, an IGBT device, and the gate protection circuit includes resistors R6, R44 and clamp protections ZD9, ZD10.

[0015] Preferably, the AC control component includes resistors R41, R42, resistors R43, R8, R18, a diode D10, transistors Q3, Q4, and a relay JK1.

[0016] Preferably, the photovoltaic panel power optimal adaptation module includes a photovoltaic panel voltage module, a gate drive module, a power switch device module, an energy storage inductor L1, a current and voltage sampling module and a DC heating tube.

[0017] Preferably, the DC-DC conversion circuit module includes a gate drive chip module, a power switch device module, an energy storage inductor L4, a fast recovery diode D26 or Q11 and D41 in a synchronous DC-DC conversion module.

[0018] Preferably, the solar photovoltaic water heater control component is provided with an anti-reverse connection module, and the solar photovoltaic water heater control component is connected in series with a temperature fuse.

[0019] The utility model discloses a solar photovoltaic water heater control assembly, which has the following beneficial effects:

[0020] The solar photovoltaic water heater control component uses the MCU to detect photovoltaic input and output, and the water tank temperature, output current and other information are fed back to adjust the duty cycle to the gate drive chip module. The gate drive module outputs a duty cycle drive signal of a certain frequency based on the information from the MCU to drive the switching time of the power switch device module, thereby adjusting the output voltage to achieve optimal adaptive use of photovoltaic solar energy and ensure that the utilization rate of photovoltaic panel electricity is improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0022] Figure 1 This is the circuit diagram of the AC / DC heating control component of the utility model;

[0023] Figure 2 This is the circuit diagram of the MCU control drive module of the utility model;

[0024] Figure 3 This is the circuit diagram of the AC control component of the utility model;

[0025] Figure 4 This is the circuit diagram of the photovoltaic panel power optimal adaptation module of the utility model;

[0026] Figure 5 This is the circuit diagram of the current and voltage sampling module of the utility model;

[0027] Figure 6 This is the boost-down conversion circuit diagram of the utility model;

[0028] Figure 7 This is the synchronous rectification DC-DC conversion circuit diagram of the utility model;

[0029] Figure 8 This is the buck-boost conversion circuit diagram of the utility model;

[0030] Figure 9 This is the DC-DC conversion circuit diagram of the asynchronous rectification circuit of the utility model;

[0031] Figure 10 This is the MOS anti-reverse connection circuit diagram of the utility model;

[0032] Figure 11 This is the reverse connection circuit diagram of the diode of the utility model;

[0033] Figure 12 This is the circuit diagram of the rectifier bridge anti-reverse connection of the utility model;

[0034] Figure 13 This is the EMI suppression processing circuit diagram of the DC-DC conversion circuit of the utility model;

[0035] Figure 14 This is the circuit diagram of the operation display panel module of the utility model;

[0036] Figure 15 This is a display diagram of the operation display panel module of the utility model. DETAILED DESCRIPTION

[0037] To make the purpose, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions in the embodiments of the present invention are clearly and completely described. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts are within the scope of protection of the present invention.

[0038] The embodiment of the present application provides a solar photovoltaic water heater control component to solve the problem that when the mains power is disconnected, the power switch tube is disconnected, the DC heating tube will not work, and the photovoltaic panel power cannot be used to the maximum and optimal extent. The MCU detects the photovoltaic input and output, and the water tank temperature, output current and other information are fed back to adjust the duty cycle to the gate drive chip module. The gate drive module outputs a duty cycle drive signal of a certain frequency according to the information of the MCU to drive the switching time of the power switch device module, thereby adjusting the output voltage, achieving optimal adaptive use of photovoltaic solar energy, and ensuring that the utilization rate of photovoltaic panel power is improved.

[0039] In order to better understand the above technical solution, the above technical solution will be described in detail below with reference to the accompanying drawings and specific implementation methods.

[0040] The embodiment of the utility model discloses a solar photovoltaic water heater control component.

[0041] According to the attached Figure 1-15 As shown, the control component includes: MCU control drive module and photovoltaic panel power optimal adaptation module,

[0042] MCU control drive module is based on AC heating and photovoltaic DC control heating control;

[0043] The MCU controls the drive module, which is used to control the gate drive chip. The gate drive chip drives the power switching device. The photovoltaic input power is dynamically adjusted by the power switching device and the energy storage inductor, that is, DC-DC conversion, and the control output adapts to the voltage and current of the photovoltaic panel and heating tube configuration.

[0044] The MCU controls the photovoltaic drive module to drive the power devices and dynamically adjusts the DC-DC conversion based on control panel control, water temperature, photovoltaic input voltage, output current and other factors.

[0045] The MCU adjusts the output through the duty cycle. The gate driver chip drives the power switching device according to the signal output from the MCU, adjusts the output voltage, achieves the optimal adaptation of photovoltaic solar energy, and ensures better utilization of photovoltaic panel electricity.

[0046] The MCU control drive module controls the AC input signal based on the control panel to realize AC heating control.

[0047] Photovoltaic panel power optimal adaptation module, which is equipped with a hardware circuit DC-DC conversion circuit, a photovoltaic panel power optimization module, and hardware and software to achieve the optimal output of photovoltaic solar energy, ensuring better utilization of photovoltaic panel power;

[0048] Hardware circuit DC-DC conversion circuit is divided into synchronous rectification converter and asynchronous rectification converter for different models and specifications of water heaters and the scale of photovoltaic panels. Synchronous rectification is further divided into half-bridge synchronous rectification and full-bridge synchronous rectification in terms of circuit structure.

[0049] When the current required for DC heating is large, a synchronous rectification circuit is used. When the current required for DC heating is not large, an asynchronous rectification circuit can be used.

[0050] Specifically, it is necessary to better control the conversion efficiency, performance, structure and cost based on the parameters of the DC heating tube and the parameters of the outdoor photovoltaic modules.

[0051] The DC-DC converter circuit, a hardware circuit in the photovoltaic panel power optimal adaptation module, is an active power regulation circuit that involves the switching action of the power switch tube and inductive energy storage. Therefore, electromagnetic interference is also a difficult and key point in controlling this component. The controller component also has EMI suppression processing.

[0052] The hardware circuit DC-DC conversion circuit is equipped with a MOSFET gate protection circuit, and a gate driver chip is installed on the MOSFET gate protection circuit. The gate driver chip ensures that the driving signal voltage meets the gate opening and closing conditions of the power switching device, and the driving current meets the opening requirements of the power switching device; appropriate gate resistance ensures the adaptation of the switching frequency and normal switching speed under low switching loss; the gate-source resistance ensures that when the input signal is open, the gate-source voltage is 0V, that is, the power switching device is in the off state.

[0053] The anti-reverse connection module prevents the photovoltaic panel power line from entering the house in reverse, protects the control circuit, and improves safety; the lightning protection surge protection circuit is also equipped with a series thermal fuse. When a module component operates abnormally and the temperature rises too high, the thermal fuse will disconnect and cut off the photovoltaic power, providing multiple safety guarantees.

[0054] The operation display panel module realizes button operation, mode selection, photovoltaic power metering, mode status indication, remote data and other functions, so that the photovoltaic panel power is optimally adapted to the module, and the hardware and software realize the optimal adaptation of the photovoltaic panel power to ensure better utilization of the photovoltaic panel power.

[0055] The MCU control drive module includes resistors R7, R46 and gate drive chip U1, ZD1, D3, C25, C4, C31, C3, and E1. One end of the resistors R7 and R46 is connected to the HO and LO pins of the MCU. E1 is a bootstrap capacitor and ZD1 is a voltage regulator to protect the gate drive chip U1.

[0056] The DC control components include resistors R1, R16, resistors R6, R44, diodes D1, D16, power switches Q10, Q11, D41, and inductor L1. Resistors R1, R16, resistors R6, R44, diodes D1, D16 adapt the power switch's turn-on and turn-off speeds, reduce switching losses, and protect the power switch.

[0057] Since different power switches or power switches with different parameters have different input, output, and reverse transmission parasitic capacitances, and because of the influence of line stray inductance and other factors, spike voltages may be generated between the drain and source. Therefore, different power switches need to select appropriate gate resistors to adapt their turn-on and turn-off speeds.

[0058] The DC control component includes its gate drive chip, which ensures that the drive signal voltage meets the gate opening and closing conditions of the power switching device, and the drive current meets the opening current of the power switching device.

[0059] The DC control components include power switch tubes MOSFET and IGBT devices. The gate protection circuit includes resistors R6, R44 and clamp protection ZD9 and ZD10, which are used for gate spike voltage protection to prevent electrostatic discharge and spike voltage, and prevent low-side power devices from self-turning on.

[0060] The AC control components include resistors R41, R42, R43, R8, R18, diode D10, transistors Q3, Q4, and relay JK1. Resistors R41, R42, R43, and transistor Q4 form the AC power detection circuit to detect whether there is AC input;

[0061] Resistors R8, R18, transistor Q3, diode D10, and relay JK1 form an AC heating control circuit, and one end of R18 is connected to the microcontroller control pin.

[0062] The photovoltaic panel power optimal adaptation module includes a photovoltaic panel voltage module, a gate drive module, a power switching device module, an energy storage inductor L1, a current and voltage sampling module, and a DC heating tube. It adjusts the DC-DC conversion circuit according to the load conditions to enable the photovoltaic panel power to be output most efficiently.

[0063] The DC-DC conversion circuit module includes a gate driver chip module, a power switch device module, an energy storage inductor L4, and a fast recovery diode D26 (see Figure 1). Alternatively, Q11 and D41 in a synchronous DC-DC conversion module are used. When the load current is relatively low, a non-synchronous rectification DC-DC conversion circuit is used, and a fast recovery diode D26 is used for freewheeling.

[0064] When the load current is relatively large, a synchronous rectifier circuit is generally used. The dead time must be set for the synchronous rectifier circuit control. During the dead time, Q11 is not turned on, and the current is continued through the body diode. Since the reverse recovery time of the body diode of the power device is slow, a Schottky diode D41 must be connected in parallel with the power device. The rated current of this diode can be relatively small because the dead time is very small.

[0065] The solar photovoltaic water heater control component is equipped with an anti-reverse connection module to prevent the photovoltaic panel power line from entering the house in the reverse direction, protecting the control circuit and improving safety;

[0066] The circuit includes but is not limited to Figure 2 D14 and D15 in Figure 5 D24 and D25, Figure 6 D19 and D20, Figure 7 D29 and D30, Figure 8 D35 and D36, Figure 9 The D47 and D48 diodes in the reverse connection protection circuit have different positions according to the different DC-DC conversion circuit topologies.

[0067] In addition, there are rectifier bridge anti-reverse connection and MOS anti-reverse connection circuits, among which MOS anti-reverse connection is divided into NMOS and PMOS anti-reverse connection.

[0068] MOS is used to prevent reverse connection for low voltage and high current, while diodes and rectifier bridges are used to prevent reverse connection for medium, high voltage and low current.

[0069] The solar photovoltaic water heater control component is connected in series with a temperature fuse. When a module component works abnormally and the temperature rises too high, the temperature fuse is disconnected and the photovoltaic power is cut off, providing multiple safety guarantees.

[0070] The DC-DC conversion circuit, a hardware circuit in the photovoltaic panel power optimization module, is an active power regulation circuit that involves the switching action of the power switch tube and inductive energy storage. The controller component also has EMI suppression processing. Inductor L8 and Cy1, Cy2, Cy3, Cy4, Cx1, and Cx2 implement common-mode and differential-mode suppression. Interference is effectively suppressed by adding filter capacitors to the communication lines, stringing magnetic beads, and PCB wiring loops.

[0071] Working principle: The MCU detects photovoltaic input and output, and uses information such as water tank temperature and output current to adjust the duty cycle and give it to the gate drive chip module. The gate drive module outputs a duty cycle drive signal of a certain frequency according to the information of the MCU to drive the switching time of the power switching device module, thereby adjusting the output voltage to achieve optimal adaptation of photovoltaic solar energy and ensure that the utilization rate of photovoltaic panel electricity is improved.

[0072] The above shows and describes the basic principles, main features and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The above embodiments and descriptions are merely illustrative of the principles of the present invention. Various changes and improvements may be made to the present invention without departing from the spirit and scope of the present invention. Such changes and improvements are intended to fall within the scope of the present invention. The scope of protection claimed in this invention is defined by the appended claims and their equivalents.

Claims

1. A solar photovoltaic water heater control component, characterized in that: include: MCU control drive module, photovoltaic panel power optimal adaptation module, anti-reverse connection module and operation display panel module, The MCU control drive module includes AC control components and DC control components; The photovoltaic panel power optimal adaptation module is provided with a hardware circuit DC-DC conversion circuit; The hardware circuit DC-DC conversion circuit is provided with a MOSFET gate protection circuit, and a gate drive chip is installed on the MOSFET gate protection circuit.

2. A solar photovoltaic water heater control assembly according to claim 1, characterized in that: The MCU control drive module includes resistors R7, R46 and gate drive chips U1, ZD1, D3, C25, C4, C31, C3, and E1. One end of the resistors R7 and R46 are connected to the HO and LO pins of the MCU. E1 is a bootstrap capacitor and ZD1 is a voltage regulator.

3. A solar photovoltaic water heater control assembly according to claim 1, characterized in that: The DC control component includes resistors R1 and R16, resistors R6 and R44, diodes D1 and D16, power switches Q10, Q11 and D41, and an inductor L1.

4. A solar photovoltaic water heater control assembly according to claim 1, characterized in that: The DC control component includes its gate drive chip.

5. A solar photovoltaic water heater control assembly according to claim 1, characterized in that: The DC control component includes a power switch tube MOSFET, an IGBT device, and a gate protection circuit includes resistors R6, R44 and clamp protections ZD9, ZD10.

6. A solar photovoltaic water heater control assembly according to claim 1, characterized in that: The AC control component includes resistors R41, R42, resistors R43, R8, R18, a diode D10, transistors Q3, Q4, and a relay JK1.

7. A solar photovoltaic water heater control assembly according to claim 1, characterized in that: The photovoltaic panel power optimal adaptation module includes a photovoltaic panel voltage module, a gate drive module, a power switch device module, an energy storage inductor L1, a current and voltage sampling module and a DC heating tube.

8. A solar photovoltaic water heater control assembly according to claim 1, characterized in that: The DC-DC conversion circuit module includes a gate drive chip module, a power switch device module, an energy storage inductor L4, a fast recovery diode D26 or Q11 and D41 in the synchronous DC-DC conversion module.

9. A solar photovoltaic water heater control assembly according to claim 1, characterized in that: The solar photovoltaic water heater control component is provided with an anti-reverse connection module, and the solar photovoltaic water heater control component is connected in series with a temperature fuse.

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