Off-grid photovoltaic inverter compatible with ip21 and ip65

Abstract

This invention provides an off-grid photovoltaic inverter compatible with IP21 and IP65 standards. The inverter has openings at the top and bottom, and consists of a fan cover, a heat sink, a power board PCB, and a fan forming a sealed airflow cavity. A first heat source is placed within this cavity, and a second heat source is connected to the heat sink. A thermistor is positioned on the heat sink near the first heat source, and its signal lines are integrated on the power board PCB and connected to a temperature controller. This invention integrates the high-efficiency heat dissipation of IP21 standards with the outdoor protection of IP65 standards, achieving a comprehensive advantage of high heat dissipation efficiency, no need for component derating, low production cost, maintenance-free operation, and high reliability, significantly expanding the product's application scenarios.

Description

Technical Field

[0001] This invention relates to a photovoltaic inverter, belonging to the field of off-grid photovoltaic inverters, and specifically to an off-grid photovoltaic inverter compatible with IP21 and IP65. Background Technology

[0002] Currently, off-grid photovoltaic inverters in the industry are mainly designed with an IP21 structural standard for their casing. Due to heat dissipation requirements, the unit needs to have an internal fan, and the casing needs to have corresponding openings to provide airflow for the fan (see attached diagram). Figure 1 This cannot cover the needs of outdoor scenarios, but if an IP65-rated overall structure is to be made (see attached diagram), it would be unacceptable. Figure 2 Furthermore, it requires externalizing the magnetic components and encapsulating them with a large amount of thermally conductive adhesive, which is too costly.

[0003] In the industry, off-grid inverters primarily use wired thermistors latched onto the heat sink for temperature control (see attached diagram). Figure 3 Firstly, it affects the assembly of the entire machine (requiring additional processing during production), and secondly, the monitoring points are relatively limited (only the radiator temperature can be monitored).

[0004] Disadvantages of existing off-grid photovoltaic inverters: 1. Limited application scenarios: Due to its IP21 overall structure, it can only be installed indoors and cannot meet the needs of clients in outdoor scenarios; 2. Actual output power loss: Because its air duct is not straight-through and the air inlet needs to be opened on the side, the temperature rise is relatively high. Some heat-generating components need to be derated to meet the demand, which means that the actual rated power output time cannot be too long, thus affecting the actual output power. 3. Short service life: Typically, the inside of the chassis becomes covered with dust after 3-6 months of use, and the dust filter needs to be replaced regularly. This not only makes the machine prone to dust accumulation and moisture damage, but also directly leads to poor heat dissipation, performance degradation, and even machine damage if the dust is not cleaned regularly. The new design eliminates the dust cover, so the machine's heat dissipation performance is not affected even after long-term use, and the maintenance cost is reduced. The magnetic components can be directly dissipated because they are exposed. 4. High design costs: a. To achieve IP65 rating, traditional off-grid inverters must use a fully enclosed casing. Internal components such as the heat-generating switching transistors and magnetic devices must be housed using thermally conductive adhesive and large heat sinks, resulting in very high costs and difficult manufacturing. (See details...) Figure 2 ) b. Traditional IP21 off-grid inverters have low heat dissipation efficiency due to their non-direct ventilation, requiring at least two fans (≥3K, off-grid inverters generally require power of 3K or more). 5. High maintenance costs: Traditional off-grid inverters require frequent replacement of dust covers to address the problem of poor heat dissipation.

[0005] 6. Temperature control is relatively simple and inconvenient to install. Traditional inverters mainly use wired thermistors attached to the heat sink, which can only monitor the temperature of the heat sink and cannot monitor the temperature of other important heat-generating components such as transformers, inductors, and capacitors.

[0006] To address the above problems, this invention proposes an off-grid photovoltaic inverter compatible with IP21 and IP65 standards. Summary of the Invention

[0007] The purpose of this invention is to address the limitations of existing technologies by proposing an off-grid photovoltaic inverter compatible with IP21 and IP65 standards.

[0008] The present invention adopts the following technical solution: The present invention discloses an off-grid photovoltaic inverter compatible with IP21 and IP65, characterized in that the inverter has openings at the top and bottom, and forms a sealed air duct cavity with a fan cover, a heat sink, a power board PCB, and a fan. A first heat source is placed in the air duct cavity, a second heat source is connected to the heat sink, a thermistor is placed at the end of the heat sink near the first heat source, and the electrical signal line of the thermistor is integrated on the power board PCB and connected to the temperature controller signal.

[0009] Preferably, a soft thermally conductive adhesive is provided between the thermistor and the heat sink.

[0010] Preferably, the first heat source includes a PV for boosting voltage, an inverter inductor for boosting or bucking voltage, and a transformer for AC-DC conversion.

[0011] Preferably, the second heat source includes a switching transistor.

[0012] Preferably, the inverter's temperature controller is used to automatically control the fan based on the signal from the thermistor, and the temperature controller is an integrated board type.

[0013] Preferably, it also includes an upper cover, a lower shell, a wiring cover, and an air duct cover.

[0014] Preferably, a waterproof connection is used between the fan cover and the heat sink; at the same time, a layer of waterproof thermally conductive adhesive is laid at the bottom of the air duct cavity.

[0015] Preferably, the components inside the air duct cavity are also covered with waterproof and thermally conductive adhesive. This ensures the overall unit meets the IP65 waterproof standard.

[0016] Preferably, the waterproof connection includes waterproofing via a sealing ring connection, and also uses waterproof screws.

[0017] The beneficial effects achieved by this invention are: This invention uses a wireless thermistor, integrating the thermistor communication line onto the power board PCB, and connecting it to the heat sink via thermal adhesive. This allows for monitoring not only the heat sink temperature but also the temperatures of heat-generating components such as inductors, transformers, and capacitors. The control system adjusts the fan speed, thereby regulating the overall temperature of the entire machine, improving reliability and fan lifespan.

[0018] The heat source of this invention is entirely in a straight air duct, resulting in low air resistance, short air path, high heat dissipation efficiency, and no need for derating of the heating device, thus meeting the requirements of full load for a long time.

[0019] Because this invention has higher ventilation efficiency than traditional methods, only one fan is needed to meet the requirements, thus reducing production costs.

[0020] To further understand the features and technical content of the present invention, please refer to the following detailed description and drawings of the present invention. However, the drawings provided are for reference and illustration only and are not intended to limit the present invention. Attached Figure Description

[0021] Figure 1 For off-grid inverters of the traditional IP21; Figure 2 For traditional IP65 off-grid inverters; Figure 3 It is a traditional thermostat; Figure 4 This is a structural diagram of Embodiment 1 of the present invention; Figure 5 For the present invention Figure 4 Detailed illustration; Figure 6 This is an assembly drawing of the complete machine according to Embodiment 2 of the present invention; Figure 7 This is a disassembly diagram of the entire machine according to Embodiment 2 of the present invention; Figure 8 This is a schematic diagram of the air duct of the present invention; Figure 9 This is a schematic diagram of the top fan cover of the present invention. Detailed Implementation

[0022] The following specific embodiments illustrate the implementation of the present invention. Those skilled in the art can understand the advantages and effects of the present invention from the content disclosed in this specification. The present invention can be implemented or applied through other different specific embodiments, and various details in this specification can also be modified and changed based on different viewpoints and applications without departing from the spirit of the present invention. Furthermore, the accompanying drawings of the present invention are for simple illustrative purposes only and are not depictions of actual dimensions; this is stated in advance. The following embodiments will further describe the relevant technical content of the present invention in detail, but the disclosed content is not intended to limit the scope of protection of the present invention.

[0023] Example 1: As Figure 2 As shown, the existing IP65-rated inverter structure includes a wiring cover, upper cover, lower shell assembly; PV inductor box, inverter inductor potting tank, large heat sink, transformer potting tank, waterproof fan; waterproof sealing ring, power board, thermally conductive ceramic gasket, and heating switch tube. Existing off-grid photovoltaic inverters are constructed as follows: Figure 2 The traditional structure requires externalizing the magnetic components and encapsulating them with a large amount of thermally conductive adhesive, which is too costly. Therefore, this invention provides an off-grid photovoltaic inverter compatible with IP21 and IP65 standards, such as... Figure 4 , Figure 5 As shown, the inverter has openings at the top and bottom, forming a sealed airflow cavity with a fan cover, heat sink, power board PCB, and fan. A first heat source is placed within this airflow cavity, and a second heat source is connected to the heat sink. A thermistor is placed at the end of the heat sink near the first heat source, and the thermistor's signal lines are integrated on the power board PCB and connected to the temperature controller signal. Two heat sinks are used and symmetrically arranged.

[0024] This allows the second heat source to be transferred to the radiator via heat conduction, and then the heat is carried away by cold air through the air duct cavity, forming an efficient direct heat dissipation method.

[0025] In this embodiment, all heat sources are located in a straight air duct, resulting in low air resistance, a short air path, high heat dissipation efficiency, and no need to derating the heat-generating devices. This allows the device to meet full load requirements for extended periods.

[0026] In this embodiment, the inverter has openings on both the top and bottom of the unit (see attached diagram). Figure 6 , Figure 6 (The lower opening is shown; the upper opening is not shown.) Since the air duct is straight, the cooling rate can be accelerated when there are openings at both the top and bottom.

[0027] Preferably, a soft thermally conductive adhesive is provided between the thermistor and the heat sink. The soft thermally conductive adhesive is thermally conductive silicone, and its location is as follows: Figure 5The shaded area. This allows for real-time monitoring of the heatsink temperature. Furthermore, the thermistor's communication lines are integrated onto the board, so there's no need to expose them. Figure 3 The thermistor (with exposed wires) is mounted on the heat sink, and the temperature of its associated inductors and capacitors is also monitored, thus all heat sources can be effectively monitored.

[0028] Preferably, the first heat source is Figure 6 The heat source 1 in the middle is a heating magnetic device, including a PV for boosting voltage, an inverter inductor for boosting and bucking voltage, and a transformer for AC-DC conversion.

[0029] Preferably, the second heat source is Figure 6 The second heat source includes a switching transistor. The switching transistor functions as a rectifier, inverter, and voltage boost / buck converter.

[0030] Preferably, the inverter's temperature controller is used to automatically control the fan based on the signal from the thermistor, and the temperature controller is an integrated board type.

[0031] Preferably, it also includes an upper cover, a lower shell, a wiring cover, and an air duct cover.

[0032] Existing technologies have convoluted air ducts (such as...) Figure 3 As shown in the figure, the air duct in this embodiment adopts a straight-through mode, which improves the utilization rate of the fan. At the same time, since the structure is compatible with IP21 and IP65, the cost of the whole machine is controlled.

[0033] In this embodiment, the temperature controller is integrated into a board, which can monitor not only the heat sink temperature, but also the temperature of inductors and capacitors, thereby controlling the fan speed and regulating the device temperature in real time, and improving the service life of the devices.

[0034] This embodiment features a newly designed ventilation system with high efficiency and a straight air duct, enhancing the product's heat dissipation capacity and providing a wider temperature rise control range. It eliminates the need for derating, further improving overall efficiency and extending product lifespan.

[0035] This embodiment reduces design and maintenance costs: it eliminates the need for frequent maintenance (replacing dust covers), and due to its strong ventilation, only one fan is needed for the same power range.

[0036] This embodiment increases reliability. Temperature monitoring can monitor not only the temperature of the heat sink, but also the temperature of the inductor and capacitor, thereby controlling the fan speed to regulate the device temperature in real time and improve the device's lifespan.

[0037] In this embodiment, all heating elements are located on the direct ventilation duct, providing ample temperature margin. Furthermore, there is no dust in other parts of the circuit board, and the ventilation duct cavity is covered with waterproof thermally conductive adhesive, ensuring that the elements are not affected by dust and thus have a longer lifespan than traditional machines.

[0038] Example 2: This example should be understood as including all the features of any of the foregoing examples, and further improving upon them. Preferably, see the accompanying drawings. Figure 6 , Figure 7 , Figure 8 , Figure 9 The off-grid photovoltaic inverter compatible with IP21 and IP65 also includes an upper cover, a lower shell, a wiring cover, and a duct cover. The fan cover and the heat sink are connected in a waterproof manner. At the same time, a layer of waterproof and thermally conductive adhesive is laid at the bottom of the duct cavity.

[0039] Preferably, the components inside the air duct cavity are also covered with waterproof and thermally conductive adhesive. This ensures the overall unit meets the IP65 waterproof standard.

[0040] Preferably, the waterproof connection includes waterproofing via a sealing ring connection, and also uses waterproof screws.

[0041] Preferably, the upper cover and wiring cover are made of plastic, and the lower shell is made of an integrally stamped and stretched part.

[0042] Preferred, such as Figure 8 As shown, the waterproof adhesive at the bottom of the air duct cavity is 5mm thick.

[0043] Preferably, the air duct is provided with a first cover plate consisting of a fan cover and a fan cover plate, and the first cover plate together with the heat sink and the power board forms the section of the air duct.

[0044] Preferably, the lower cover has a waterproof silicone ring at the input / output terminals, and the screws are waterproof screws. The waterproof screws have screw sealing rings.

[0045] Preferably, the LCD on the lower cover is equipped with a waterproof LCD film.

[0046] Preferably, it is equipped with a wiring cover sealing ring, an upper cover sealing ring, an air duct cover sealing ring, a fan cover, and a radiator splicing sealing ring.

[0047] This embodiment further defines the structure that is compatible with IP65. It is not only compatible with IP65 in terms of external structure, but also fundamentally compatible with IP65 outdoor use scenarios that require waterproofing through waterproof design.

[0048] This embodiment solves the compatibility mode under the dual conditions of IP21 ventilation and IP65 waterproof. The air duct adopts a straight-through mode, which improves the utilization rate of the fan and controls the overall cost of the machine.

[0049] This embodiment has a low cost for the outer shell: the lower shell is made of a one-piece stamped and stretched part, which makes the outer shell mold integrally formed, and the upper cover and wiring cover are made of plastic parts. The lower shell is made of a one-piece stamped and stretched part, which reduces high-cost processing technology (such as housing welding) and high-cost raw materials (magnetic device potting tank, large heat sink, ceramic gasket).

[0050] Because this invention has higher ventilation efficiency than traditional methods, only one fan is needed to meet the requirements. Since all exposed cavities are covered with adhesive, this invention eliminates the need for dust covers and frequent maintenance.

[0051] The content disclosed above is only a preferred and feasible embodiment of the present invention, and is not intended to limit the scope of protection of the present invention. Therefore, all equivalent technical changes made based on the content of the present invention specification and drawings are included within the scope of protection of the present invention. Furthermore, the elements therein can be updated as technology develops.

Claims

1. An off-grid photovoltaic inverter compatible with IP21 and IP65, characterized in that, The inverter has openings at the top and bottom. It consists of a fan cover, a heat sink, a power board PCB, and a fan forming a sealed airflow cavity. The first heat source is placed in the airflow cavity, and the second heat source is connected to the heat sink. The thermistor is placed at the end of the heat sink near the first heat source, and the electrical signal line of the thermistor is integrated on the power board PCB and connected to the temperature controller signal.

2. An off-grid photovoltaic inverter compatible with IP21 and IP65 as described in claim 1, characterized in that, A soft thermally conductive adhesive is provided between the thermistor and the heat sink.

3. An off-grid photovoltaic inverter compatible with IP21 and IP65 as described in claim 2, characterized in that, The first heat source includes a PV for boosting voltage, an inverter inductor for boosting or bucking voltage, and a transformer for AC-DC conversion.

4. An off-grid photovoltaic inverter compatible with IP21 and IP65 as described in claim 3, characterized in that, The second heat source includes a switching transistor.

5. An off-grid photovoltaic inverter compatible with IP21 and IP65 as described in claim 4, characterized in that, The inverter's temperature controller is used to automatically control the fan based on the signal from the thermistor. The temperature controller is integrated into a circuit board.

6. An off-grid photovoltaic inverter compatible with IP21 and IP65 as described in claim 5, characterized in that, It also includes the top cover, bottom shell, wiring cover, and air duct cover.

7. An off-grid photovoltaic inverter compatible with IP21 and IP65 as described in claim 6, characterized in that, A waterproof connection is used between the fan cover and the heat sink; at the same time, a layer of waterproof thermally conductive adhesive is laid at the bottom of the air duct cavity.

8. An off-grid photovoltaic inverter compatible with IP21 and IP65 as described in claim 7, characterized in that, The components inside the air duct cavity are also covered with waterproof and thermally conductive adhesive.

9. An off-grid photovoltaic inverter compatible with IP21 and IP65 as described in claim 8, characterized in that, The waterproof connection includes a sealing ring connection and a waterproof screw.

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