Photovoltaic system fault escape circuit

Abstract

The application belongs to the technical field of photovoltaic power generation, and particularly relates to a power optimizer escape circuit applied to a group string type photovoltaic system, which comprises: a fault detection unit for monitoring the working state of the power optimizer and outputting a control signal; a channel switching unit responding to the control signal output by the fault detection unit; a main power channel containing a power regulation module, used for transmitting and regulating the output power of a photovoltaic module when the power optimizer is normally working; and an escape channel used for transmitting the output power of the photovoltaic module when the power optimizer is faulty. The application constructs an intelligent switching channel through double MOSFET switches, seamlessly switches to a passive bypass path when the optimizer is faulty, guarantees the continuous power generation of the module, completely avoids the high-voltage electric shock risk through the hardware-level direct current channel, automatically restores the operation of the main power channel after the fault is eliminated, does not need manual intervention, and finally realizes the minimization of power generation loss, the maximization of system safety, and the fundamental reduction of operation and maintenance cost.

Description

Technical Field

[0001] This invention belongs to the field of photovoltaic power generation technology, specifically relating to an escape circuit for a power optimizer applied to a string photovoltaic system. Background Technology

[0002] A photovoltaic (PV) system is a power generation device that converts solar energy into electrical energy. It mainly consists of PV modules, a power optimizer, an inverter, and grid connection equipment. The PV modules generate direct current (DC), the power optimizer performs maximum power point tracking (MPPT) and voltage / current optimization on individual or string modules, and the inverter converts the DC to alternating current (AC) and feeds it into the grid. System efficiency is highly dependent on the normal operation of the power optimizer, and the fault escape circuit is a core safety redundancy design of the PV power optimizer, providing a current bypass path in the event of an internal fault. Its core function is to use hardware switching to allow the PV module current to bypass the faulty main power regulation module and output directly, ensuring continuous power generation during a fault while eliminating the risk of high-voltage electric shock.

[0003] Therefore, the fault escape circuit and the photovoltaic system form a symbiotic relationship: as an embedded protection unit of the power optimizer, it directly determines the system's power generation capacity and safety during partial faults. Traditional systems, lacking this design, suffer complete module shutdown due to a single point of failure; while the optimizer with integrated escape circuit can maintain part of the system's power generation capacity, significantly improving overall reliability.

[0004] Generally, traditional solutions employ a two-stage shutdown mechanism: when a fault is detected, the power optimizer completely shuts off its output (level one shutdown), or it relies on the inverter side to shut down (level two shutdown). The former results in zero power generation from the faulty component; the latter poses a high-voltage safety hazard because the component remains energized, and both solutions require manual reset to restore power generation, leading to power loss and increased maintenance costs.

[0005] Based on this, the present invention provides a photovoltaic system fault escape circuit to solve the above-mentioned technical problems. Summary of the Invention

[0006] The purpose of this invention is to provide a fault escape circuit for a photovoltaic system, thereby solving the problems mentioned in the background art.

[0007] To achieve the above objectives, the present invention provides the following technical solution:

[0008] This invention provides a fault escape circuit for a photovoltaic system, comprising:

[0009] The fault detection unit is used to monitor the operating status of the power optimizer and output control signals;

[0010] The channel switching unit responds to the control signal output by the fault detection unit;

[0011] The main power channel, which includes a power conditioning module, is used to transmit and regulate the output power of the photovoltaic modules when the power optimizer is working normally;

[0012] An escape route is used to transfer the output power of the photovoltaic modules in the event of a power optimizer failure;

[0013] The channel switching unit includes a first switch Q1 and a second switch Q3;

[0014] The controlled terminal of the second switching transistor Q3 is connected to the output terminal of the fault detection unit to receive the control signal;

[0015] The controlled terminal of the first switch Q1 is connected between the output terminal of the second switch Q3 and the reference ground;

[0016] The escape route is formed by the first switch Q1 in the conducting state;

[0017] The input end of the main power channel and the input end of the escape channel are both connected to the positive electrode of the photovoltaic module;

[0018] The output terminals of the main power channel and the escape channel are both connected to the system output terminal.

[0019] Preferably, the connection relationship between the first switch Q1 and the second switch Q3 is as follows:

[0020] a1. When the fault detection unit detects that the power optimizer is working normally, it outputs a high-level control signal to turn on the second switch Q3, thereby turning off the first switch Q1, and the current flows through the main power channel.

[0021] a2. When the fault detection unit detects a fault in the power optimizer, it outputs a low-level control signal to turn off the second switch Q3, thereby turning on the first switch Q1, and allowing current to flow through the escape channel.

[0022] Preferably, the power optimizer fault type includes at least one of MPPT failure, over-temperature protection triggering, or communication interruption.

[0023] Preferably, both the first switch Q1 and the second switch Q3 are MOSFET transistors.

[0024] Preferably, the source of the first switch Q1 is connected to the positive terminal of the photovoltaic module, and the drain is connected to the system output terminal.

[0025] Preferably, the drain of the second switch Q3 is connected to the gate of the first switch Q1, and the source is grounded.

[0026] Preferably, the main power channel includes a DC-DC converter circuit for realizing maximum power point tracking (MPPT) and voltage / current conversion.

[0027] Preferably, it further includes an automatic recovery unit for controlling the channel switching unit to switch the current path from the escape channel back to the main power channel after the fault is cleared.

[0028] Preferably, the escape channel is a passive direct path, which allows the output current of the photovoltaic module to directly bypass the power regulation module in the main power channel when the circuit is open.

[0029] Compared with the prior art, the beneficial effects of the present invention are:

[0030] This invention constructs an intelligent switching channel through dual MOSFET switches, seamlessly switching to a passive bypass path in the event of an optimizer failure, ensuring continuous power generation of the components, and completely avoiding the risk of high-voltage electric shock through the hardware-level DC path; after the fault is cleared, the main power channel is automatically restored to operation without manual intervention, ultimately minimizing power generation loss, maximizing system safety, and fundamentally reducing operation and maintenance costs. Attached Figure Description

[0031] Figure 1 This is a fault escape circuit diagram for the photovoltaic system of the present invention;

[0032] Figure 2 This is a structural diagram of the photovoltaic system fault escape circuit unit of the present invention. Detailed Implementation

[0033] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0034] Example 1, please refer to Figure 1 and Figure 2 The present invention provides a photovoltaic system fault escape circuit, comprising:

[0035] The fault detection unit is used to monitor the operating status of the power optimizer and output control signals;

[0036] The channel switching unit responds to the control signal output by the fault detection unit;

[0037] The main power channel, which includes a power conditioning module, is used to transmit and regulate the output power of the photovoltaic modules when the power optimizer is working normally;

[0038] An escape route is used to transfer the output power of the photovoltaic modules in the event of a power optimizer failure;

[0039] The channel switching unit includes a first switch Q1 and a second switch Q3;

[0040] The controlled terminal of the second switching transistor Q3 is connected to the output terminal of the fault detection unit to receive the control signal;

[0041] The controlled terminal of the first switch Q1 is connected between the output terminal of the second switch Q3 and the reference ground;

[0042] The escape route is formed by the first switch Q1 in the conducting state;

[0043] The input end of the main power channel and the input end of the escape channel are both connected to the positive electrode of the photovoltaic module;

[0044] The output terminals of the main power channel and the escape channel are both connected to the system output terminal.

[0045] It should also be noted that the connection relationship between the first switch Q1 and the second switch Q3 is as follows:

[0046] a1. When the fault detection unit detects that the power optimizer is working normally, it outputs a high-level control signal to turn on the second switch Q3, thereby turning off the first switch Q1, and the current flows through the main power channel.

[0047] a2. When the fault detection unit detects a fault in the power optimizer, it outputs a low-level control signal to turn off the second switch Q3, thereby turning on the first switch Q1, and allowing current to flow through the escape channel.

[0048] It should also be noted that the power optimizer fault types include at least one of MPPT failure, over-temperature protection triggering, or communication interruption.

[0049] It should also be noted that both the first switch Q1 and the second switch Q3 are MOSFET transistors.

[0050] It should also be noted that the source of the first switching transistor Q1 is connected to the positive terminal of the photovoltaic module, and the drain is connected to the system output terminal.

[0051] It should also be noted that the drain of the second switch Q3 is connected to the gate of the first switch Q1, and the source is grounded.

[0052] It should also be noted that the main power channel includes a DC-DC converter circuit, which is used to achieve maximum power point tracking (MPPT) and voltage / current conversion.

[0053] Preferably, it further includes an automatic recovery unit for controlling the channel switching unit to switch the current path from the escape channel back to the main power channel after the fault is cleared.

[0054] It should also be noted that the escape route is a passive direct path, which allows the output current of the photovoltaic module to directly bypass the power regulation module in the main power channel when the circuit is open.

[0055] Example 2: In practical applications, please refer to... Figure 1 The photovoltaic power optimizer fault escape circuit of this invention mainly comprises four parts: a fault detection unit, a channel switching unit, a main power channel, and an escape channel. When the fault detection unit detects a fault in the optimizer system, such as MPPT failure, overheating, or communication interruption, the switching unit controls the channel to switch from the main power channel to the escape channel to ensure normal power generation of the photovoltaic modules. After the system fault is cleared, it switches back to the main power channel.

[0056] Please see Figure 2 After the optimizer is connected to the module, the fault detection unit checks whether the optimizer is abnormal. If there is no abnormality, the Control signal is high, Q3 is turned on, the gate of Q1 is low, Q1 is turned off, and the current flows through the main power module, performing normal power regulation. If there is an abnormality, the Control signal is low, Q3 is turned off, the gate of Q1 is high, Q1 is turned on, and the current flows through the escape channel. Even if the optimizer is damaged, it will not affect the power generation of the module.

[0057] In summary, this invention achieves three breakthroughs by constructing an intelligent switching channel using dual MOSFET switches: first, seamless switching to a passive bypass path in the event of an optimizer failure, ensuring continuous power generation from the components; second, a hardware-level DC path that completely eliminates the risk of high-voltage electric shock; and third, automatic restoration of the main power channel operation after the fault is cleared, requiring no manual intervention. Ultimately, this minimizes power generation losses, maximizes system safety, and fundamentally reduces operation and maintenance costs.

[0058] In the description of this specification, references to terms such as "an embodiment," "example," "specific example," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0059] The preferred embodiments of the present invention disclosed above are merely illustrative of the invention. These preferred embodiments do not exhaustively describe all details, nor do they limit the invention to the specific implementations described. Clearly, many modifications and variations can be made based on the content of this specification. This specification selects and specifically describes these embodiments to better explain the principles and practical applications of the invention, thereby enabling those skilled in the art to better understand and utilize the invention. The invention is limited only by the claims and their full scope and equivalents.

Claims

1. A fault escape circuit for a photovoltaic system, characterized in that, include: The fault detection unit is used to monitor the operating status of the power optimizer and output control signals; The channel switching unit responds to the control signal output by the fault detection unit; The main power channel, which includes a power conditioning module, is used to transmit and regulate the output power of the photovoltaic modules when the power optimizer is working normally; An escape route is used to transfer the output power of the photovoltaic modules in the event of a power optimizer failure; The channel switching unit includes a first switch Q1 and a second switch Q3; The controlled terminal of the second switching transistor Q3 is connected to the output terminal of the fault detection unit to receive the control signal; The controlled terminal of the first switch Q1 is connected between the output terminal of the second switch Q3 and the reference ground; The escape route is formed by the first switch Q1 in the conducting state; The input end of the main power channel and the input end of the escape channel are both connected to the positive electrode of the photovoltaic module; The output terminals of the main power channel and the escape channel are both connected to the system output terminal.

2. The photovoltaic system fault escape circuit according to claim 1, characterized in that, The connection relationship between the first switch Q1 and the second switch Q3 is as follows: a1. When the fault detection unit detects that the power optimizer is working normally, it outputs a high-level control signal to turn on the second switch Q3, thereby turning off the first switch Q1, and the current flows through the main power channel. a2. When the fault detection unit detects a fault in the power optimizer, it outputs a low-level control signal to turn off the second switch Q3, thereby turning on the first switch Q1, and allowing current to flow through the escape channel.

3. A photovoltaic system fault escape circuit according to claim 2, characterized in that, The power optimizer fault types include at least one of MPPT failure, over-temperature protection triggering, or communication interruption.

4. A photovoltaic system fault escape circuit according to claim 3, characterized in that, Both the first switch Q1 and the second switch Q3 are MOSFET transistors.

5. A photovoltaic system fault escape circuit according to claim 4, characterized in that, The source of the first switch Q1 is connected to the positive terminal of the photovoltaic module, and the drain is connected to the system output terminal.

6. A photovoltaic system fault escape circuit according to claim 5, characterized in that, The drain of the second switch Q3 is connected to the gate of the first switch Q1, and the source is grounded.

7. A photovoltaic system fault escape circuit according to claim 6, characterized in that, The main power channel includes a DC-DC converter circuit for achieving maximum power point tracking (MPPT) and voltage / current conversion.

8. A photovoltaic system fault escape circuit according to claim 7, characterized in that, It also includes an automatic recovery unit for controlling the channel switching unit to switch the current path from the escape channel back to the main power channel after the fault is cleared.

9. A photovoltaic system fault escape circuit according to claim 8, characterized in that, The escape channel is a passive direct path, which allows the output current of the photovoltaic module to directly bypass the power regulation module in the main power channel when the circuit is on.

Images