A reverse current prevention controller, a reverse current prevention reclosing circuit breaker and a photovoltaic system

Abstract

The utility model relates to circuit breaker technical field discloses a kind of anti -reverse flow controller, anti -reverse flow reclosing circuit breaker and photovoltaic system, wherein, anti -reverse flow controller includes: control unit, voltage current detection unit, temperature detection unit and drive unit, wherein, the input end of voltage current detection unit gathers the voltage signal and current signal of public power grid grid-connected place;The input end of temperature detection unit gathers the temperature signal of the first end of external switch unit;The first output end of control unit is connected with the control end of drive unit;The output end of drive unit is connected with the control end of external switch unit;Control unit, voltage current detection unit, temperature detection unit, drive unit and external switch unit are packaged in same shell.The utility model simplifies the structure and wiring of anti -reverse flow controller, reduce cost.

Description

Technical Field

[0001] This utility model relates to the field of circuit breaker technology, specifically to an anti-backflow controller, an anti-backflow reclosing circuit breaker, and a photovoltaic system. Background Technology

[0002] In grid-connected systems such as distributed photovoltaic power generation and small-scale wind power generation, to ensure grid frequency and voltage stability and the safety of maintenance personnel, it is necessary to strictly prevent the reverse flow of generated electricity into the grid, i.e., "anti-reverse current." The most widely used rigid anti-reverse current technology in the industry currently achieves a functional closed loop through a combination architecture of "anti-reverse current controller + main circuit breaker," but it has the following problems: 1. Significant disadvantages in cost and economy: Rigid anti-backflow technology requires the simultaneous purchase of two core devices: an anti-backflow controller and a dedicated high-voltage circuit breaker. Both types of devices contain independent hardware circuits and control modules, and the combined installation and commissioning costs result in a high cost for the anti-backflow function of a single system.

[0003] 2. Response delay leads to power grid assessment risk: From the detection of reverse power, analysis and judgment, and sending of instructions by the anti-reverse current controller to the mechanical action of the circuit breaker to complete the tripping, there is an inherent response delay in the whole process. During this period, even a short-term instantaneous reverse current may be captured by the monitoring device of the power grid dispatching system, thereby triggering the assessment mechanism of the power grid operator.

[0004] 3. Operation and maintenance and reliability risks: The complex circuit structure increases the difficulty of troubleshooting. Problems such as signal transmission failure between the controller and the circuit breaker, and wear of mechanical parts of the circuit breaker may cause the anti-reverse current function to fail. In addition, manual on-site reset is required after each trip, which will prolong the system downtime in unattended power stations. Utility Model Content

[0005] This invention provides an anti-backflow controller, an anti-backflow reclosing circuit breaker, and a photovoltaic system to solve the problem of complex structure in traditional reclosing control devices.

[0006] In a first aspect, this utility model provides an anti-reverse current controller, applied to a grid-connected system including a public power grid and local distributed power sources. The anti-reverse current controller includes: a control unit, a voltage and current detection unit, a temperature detection unit, and a drive unit. The input terminal of the voltage and current detection unit collects voltage and current signals at the point of grid connection with the public power grid. The first and second output terminals of the voltage and current detection unit are respectively connected to the first and second input terminals of the control unit. The input terminal of the temperature detection unit collects the temperature signal from the first terminal of an external switch unit. The output terminal of the temperature detection unit is connected to the third input terminal of the control unit. The first output terminal of the control unit is connected to... The control unit is connected to the control unit, which is used to calculate the power flow direction at the grid connection point based on voltage and current signals, and outputs a first drive signal and a second drive signal based on temperature signals when power reverse flow is detected. The output of the drive unit is connected to the control unit of the external switch unit. The first end of the external switch unit is connected to the local distributed power source, and the second end of the external switch unit is connected to the public power grid. The drive unit is used to control the on / off state of the external switch unit based on the first and second drive signals to control the local distributed power source to disconnect from the grid. The control unit, voltage and current detection unit, temperature detection unit, drive unit, and external switch unit are encapsulated in the same housing.

[0007] The anti-reverse current controller provided by this utility model collects electrical signals at the grid connection point in real time through an integrated voltage and current detection unit, and the control unit calculates the power flow direction. When it detects power reverse flow from the local distributed power source to the public grid, it can quickly respond and output a drive signal. The drive unit quickly cuts off the grid connection switch, thereby actively preventing reverse power from being injected into the grid. This effectively solves the problem of instantaneous reverse current exceeding the limit caused by the coordination delay between the external controller and the circuit breaker in traditional solutions. At the same time, the built-in temperature detection unit continuously monitors the switching nodes and triggers protective tripping when overheating occurs, further improving system reliability. This controller highly integrates detection, judgment, and execution functions, which not only improves response speed but also significantly reduces system cost and installation complexity, providing an efficient, compact, and reliable localized protection method for the safe grid connection of distributed energy.

[0008] The anti-backflow controller provided by this utility model achieves integrated and modular anti-backflow protection by highly integrating and encapsulating the control unit, voltage and current detection unit, temperature detection unit, drive unit, and switch unit in the same housing. This integrated design completely eliminates the complex external wiring and communication interfaces between the controller, sensor, and actuator in traditional separate solutions. It not only greatly simplifies the system wiring and installation process and reduces the overall cost and probability of failure, but also improves the response speed of backflow detection and protection due to the extremely short internal signal path, fundamentally eliminating the problem of instantaneous backflow exceeding the limit caused by response delay.

[0009] In one optional embodiment, the temperature detection unit includes: a first resistor, a second resistor, a first capacitor, an inductor, and a thermistor, wherein the first end of the first resistor is connected to the first end of the first capacitor and the third input terminal of the control unit; the second end of the first resistor is connected to the first end of the second resistor and the first end of the inductor; the second end of the second resistor is connected to the second end of the first capacitor and grounded; the second end of the inductor is connected to the first end of the thermistor; and the second end of the thermistor collects the supply voltage.

[0010] In one optional embodiment, the voltage and current detection unit includes a voltage sampling circuit and a current sampling circuit, wherein the input terminal of the voltage sampling circuit acquires the voltage signal at the grid connection point, and the output terminal of the voltage sampling circuit is connected to the first input terminal of the control unit; the input terminal of the current sampling circuit acquires the current signal at the grid connection point, and the output terminal of the current sampling circuit is connected to the second input terminal of the control unit.

[0011] In one optional embodiment, the current sampling circuit includes: a third resistor, a fourth resistor, a fifth resistor, a second capacitor, and a third capacitor, wherein the first end of the third resistor is connected to the first end of the fourth resistor and the positive terminal of the public power grid at the grid connection point; the second end of the third resistor is connected to the first end of the second capacitor and the second input terminal of the control unit; the second end of the fourth resistor is connected to the first end of the fifth resistor and the negative terminal of the public power grid at the grid connection point; the second end of the fifth resistor is connected to the first end of the third capacitor and the second input terminal of the control unit; and the second end of the second capacitor is connected to the second end of the third capacitor and grounded.

[0012] In one optional embodiment, the voltage sampling circuit includes: a sixth resistor, a seventh resistor, an eighth resistor, a ninth resistor, a tenth resistor, an eleventh resistor, a twelfth resistor, a fourth capacitor, a fifth capacitor, and a voltage transformer. The first terminal of the seventh resistor is connected to the positive terminal of the public power grid at the grid connection point, and the second terminal of the seventh resistor is connected to the first terminal of the eighth resistor. The second terminal of the eighth resistor is connected to the first terminal of the voltage transformer. The first terminal of the eleventh resistor is connected to the negative terminal of the public power grid at the grid connection point, and the second terminal of the eleventh resistor is connected to the first terminal of the twelfth resistor. The second terminal of the twelfth resistor is connected to the second terminal of the voltage transformer. The first terminal of the ninth resistor is connected to the first terminal of the sixth resistor and the third terminal of the voltage transformer, and the second terminal of the ninth resistor is connected to the first terminal of the tenth resistor and the fourth terminal of the voltage transformer. The second terminal of the sixth resistor is connected to the first terminal of the fourth capacitor and the first input terminal of the control unit. The second terminal of the tenth resistor is connected to the first terminal of the fifth capacitor and the first input terminal of the control unit. The second terminal of the fourth capacitor is connected to the second terminal of the fifth capacitor and grounded.

[0013] In one optional embodiment, the anti-reverse current controller further includes a voltage conversion unit, wherein the input terminal of the voltage conversion unit receives the voltage of the public power grid, and the output terminal of the voltage conversion unit outputs the supply voltage.

[0014] In one optional embodiment, the voltage conversion unit includes: an input preprocessing circuit, a drive control circuit, and a voltage regulator circuit. The input terminal of the input preprocessing circuit receives the voltage from the public power grid, and its output terminal is connected to the input terminal of the drive control circuit. The input preprocessing circuit clamps and filters the voltage from the public power grid before outputting a preprocessed voltage. The output terminal of the drive control circuit is connected to the input terminal of the voltage regulator circuit. The drive control circuit rectifies and filters the preprocessed voltage before outputting a primary supply voltage. The voltage regulator circuit regulates the primary supply voltage before outputting the supply voltage.

[0015] In one optional embodiment, the anti-backflow controller further includes a display unit, wherein the control terminal of the display unit is connected to the second output terminal of the control unit, and the display unit is used to display the status information of the control unit.

[0016] Secondly, this utility model provides an anti-reverse current reclosing circuit breaker, comprising: a housing, a circuit breaker body, and an anti-reverse current controller according to the first aspect or any corresponding embodiment thereof, wherein the anti-reverse current controller and the circuit breaker body are both integrated in the housing, the voltage input terminal of the voltage and current detection unit in the anti-reverse current controller collects the voltage signal at the grid connection point of the public power grid through the second terminal of the circuit breaker body, and the current input terminal of the voltage and current detection unit collects the current signal at the grid connection point of the public power grid; the first terminal of the circuit breaker body is connected to the local distributed power source, and the control terminal of the circuit breaker body is connected to the output terminal of the drive unit in the anti-reverse current controller.

[0017] The anti-backflow reclosing circuit breaker provided by this utility model is an integrated reclosing device with intelligent anti-backflow protection capabilities. This device directly collects real-time electrical parameters of the grid connection point through an internally integrated voltage and current detection unit, and uses a built-in control unit to determine the power flow direction. When backflow is detected, it directly drives the circuit breaker's tripping mechanism to perform rapid tripping. This integrated design eliminates the external wiring, communication delays, and coordination costs associated with independent anti-backflow controllers and circuit breakers in traditional solutions. This not only greatly simplifies the system structure and reduces space occupation but also achieves extremely fast protection response speed due to the extremely short signal path, fundamentally eliminating the risk of instantaneous backflow exceeding limits caused by response delays. Simultaneously, the device retains the reclosing function, automatically restoring power supply after backflow elimination, achieving autonomous operation integrating detection, protection, and restoration, significantly improving the safety, reliability, and economy of distributed energy grid-connected systems.

[0018] Thirdly, this utility model provides a photovoltaic system, including: a photovoltaic power generation device and the anti-reverse current reclosing circuit breaker mentioned in the second aspect above, wherein the first end of the anti-reverse current reclosing circuit breaker is connected to the photovoltaic power generation device, and the second end of the anti-reverse current reclosing circuit breaker is connected to the public power grid.

[0019] The photovoltaic system provided by this utility model integrates millisecond-level reverse current protection capabilities directly into key grid-connected nodes by building the system on top of an anti-reverse current reclosing circuit breaker. This circuit breaker, as the core protection unit of the system, monitors the balance between photovoltaic power generation and load demand in real time. It rapidly disconnects the grid connection the instant that a power surplus might cause reverse current, physically blocking unauthorized power feeding and ensuring the power station strictly complies with grid anti-reverse current regulations. This solution replaces the complex combination of traditional controller-transformer-circuit breaker with a single integrated device, simplifying the system architecture, reducing construction and operation costs, and effectively ensuring the long-term compliant operation and revenue security of the photovoltaic power station by improving the real-time performance and reliability of protection. Attached Figure Description

[0020] To more clearly illustrate the specific embodiments of this utility model or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this utility model. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0021] Figure 1 This is a first configuration diagram of the anti-backflow controller according to an embodiment of the present utility model; Figure 2 This is a detailed circuit diagram of the temperature detection unit according to an embodiment of the present invention; Figure 3 This is a detailed circuit diagram of the current sampling circuit according to an embodiment of the present invention; Figure 4 This is a detailed circuit diagram of the voltage sampling circuit according to an embodiment of the present invention; Figure 5 This is a second composition diagram of the anti-backflow controller according to an embodiment of the present utility model; Figure 6 This is a specific circuit diagram of the voltage conversion unit according to an embodiment of the present utility model; Figure 7 This is a diagram illustrating the composition of the anti-reverse current reclosing circuit breaker according to an embodiment of the present invention. Figure 8 This is a composition diagram of a photovoltaic system according to an embodiment of the present utility model. Detailed Implementation

[0022] To make the objectives, technical solutions, and advantages of the embodiments of this utility model clearer, the technical solutions of the embodiments of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this utility model, not all embodiments. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of this utility model.

[0023] It is understood that before using the technical solutions disclosed in the various embodiments of this utility model, users should be informed of the types, scope of use, and usage scenarios of the personal information involved in this utility model in an appropriate manner in accordance with relevant laws and regulations, and user authorization should be obtained.

[0024] The terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this utility model, "a plurality of" means two or more, unless otherwise explicitly specified.

[0025] This embodiment provides an anti-reverse current controller, applicable to grid-connected systems that include both public power grids and local distributed power sources, such as... Figure 1 As shown, the anti-reverse current controller includes: voltage and current detection unit 1, temperature detection unit 2, control unit 3, and drive unit 4.

[0026] Figure 1 In the process, the input terminal of the voltage and current detection unit 1 collects the voltage and current signals at the grid connection point of the public power grid, and the first output terminal and the second output terminal of the voltage and current detection unit 1 are respectively connected to the first input terminal and the second input terminal of the control unit 3.

[0027] Specifically, Figure 1 In this system, voltage and current detection unit 1 captures the instantaneous voltage and current waveforms at the grid connection point of the public power grid and the local distributed power system in real time through its voltage and current input interfaces. Voltage and current detection unit 1 integrates a high-precision signal conditioning circuit (which may include transformers, voltage divider networks, and filtering devices) to safely isolate, scale, and suppress noise in the acquired high-voltage and high-current signals, converting them into standardized low-voltage analog or digital signals that can be processed by control unit 3. Subsequently, voltage and current detection unit 1 transmits the processed voltage and current signals to the corresponding signal acquisition ports of control unit 3 through its first and second output channels, respectively.

[0028] Figure 1In the process, the input terminal of the temperature detection unit 2 collects the temperature signal from the first terminal of the external switch unit, and the output terminal of the temperature detection unit 2 is connected to the third input terminal of the control unit 3.

[0029] Specifically, Figure 1 In this circuit, temperature detection unit 2, through its configured temperature sensor, can closely attach to the thermistor element mounted on the surface of the first end guide component of the external switching unit, and sense the temperature change at this critical connection point in real time, converting it into a corresponding electrical signal. Temperature detection unit 2 incorporates signal conditioning circuits for amplification, filtering, and linearization processing to amplify, reduce noise, and standardize the original temperature sensing signal, eliminating environmental interference and improving measurement accuracy and stability. The processed high-precision temperature signal is then transmitted to the third input terminal of control unit 3.

[0030] Figure 1 In the process, the first output terminal of the control unit 3 is connected to the control terminal of the drive unit 4. The control unit 3 is used to calculate the power flow direction at the grid connection based on the voltage signal and the current signal, and outputs the first drive signal and the second drive signal based on the temperature signal when the power reverse flow is detected.

[0031] Specifically, Figure 1 In this system, control unit 3 uses embedded, mature computing software to process voltage and current signals based on instantaneous power theory or zero-crossing phase comparison method. It calculates the instantaneous active power value and direction at the grid connection point in real time to determine if there is reverse power flow from the local distributed power source to the public grid. When the amplitude of the reverse active power detected by control unit 3 exceeds a preset threshold, a reverse flow fault is determined, and a first drive signal is immediately output. Simultaneously, control unit 3 continuously monitors the temperature signal; if the signal exceeds a safety threshold, an over-temperature condition is determined, and a second drive signal is immediately output.

[0032] Figure 1 In this configuration, the output terminal of the drive unit 4 is connected to the control terminal of the external switch unit. The first terminal of the external switch unit is connected to the local distributed power source, and the second terminal of the external switch unit is connected to the public power grid. The drive unit 4 is used to control the on / off state of the external switch unit based on the first drive signal and the second drive signal, so as to control the local distributed power source and disconnect it from the grid.

[0033] Specifically, Figure 1 In this configuration, both the first and second drive signals serve as trigger commands. When the drive unit 4 receives the first or second drive signal, it immediately outputs an electrical signal to the control terminal of the external switch unit to drive the external switch unit to operate. This causes the external switch unit to quickly disconnect the main circuit connecting the local distributed power source and the public power grid, enabling a rapid and reliable response to reverse current or overheating faults.

[0034] Figure 1 In this unit, the control unit 3, voltage and current detection unit 1, temperature detection unit 2, drive unit 4, and external switch unit are encapsulated in the same housing.

[0035] Specifically, Figure 1 In this design, the control unit 3, voltage and current detection unit 1, temperature detection unit 2, drive unit 4, and external switch unit are physically integrated and encapsulated within the same protective housing. This integrated housing serves as the sole external enclosure for the entire device. This design eliminates the external connection cables and interfaces between multiple independent devices found in traditional solutions, allowing the complete protection logic—from voltage and current signal acquisition, temperature monitoring, and reverse current detection to tripping execution—to be completed within a sealed space. This significantly improves the overall reliability, anti-interference capability, and environmental adaptability of the system, while also significantly reducing the installation size. It achieves modularity, compactness, and plug-and-play functionality for the anti-reverse current protection device.

[0036] The anti-reverse current controller provided in this embodiment collects electrical signals from the grid connection point in real time through an integrated voltage and current detection unit. The control unit calculates the power flow direction. When it detects power reversal from the local distributed power source to the public grid, it can quickly respond and output a drive signal. The drive unit quickly disconnects the grid connection switch, thereby actively preventing reverse power from being injected into the grid. This effectively solves the problem of instantaneous reverse current exceeding the limit caused by the coordination delay between the external controller and the circuit breaker in traditional solutions. At the same time, the built-in temperature detection unit continuously monitors the switching nodes and triggers protective tripping when overheating occurs, further improving system reliability. This controller highly integrates detection, judgment, and execution functions, which not only improves response speed but also significantly reduces system cost and installation complexity, providing an efficient, compact, and reliable localized protection method for the safe grid connection of distributed energy.

[0037] The backflow prevention controller provided in this embodiment integrates the control unit, voltage and current detection unit, temperature detection unit, drive unit, and switching unit into a single housing, achieving integrated and modular backflow prevention protection. This integrated design completely eliminates the complex external wiring and communication interfaces between the controller, sensors, and actuators in traditional separate solutions. This not only greatly simplifies system wiring and installation processes and reduces overall costs and failure probability, but also improves the response speed of backflow detection and protection due to the extremely short internal signal path, fundamentally eliminating the problem of instantaneous backflow exceeding limits caused by response delays.

[0038] In some alternative implementations, such as Figure 2As shown, the temperature detection unit includes: a first resistor R1, a second resistor R2, a first capacitor C1, an inductor L1, and a thermistor RT1. The first end of the first resistor R1 is connected to the first end of the first capacitor C1 and the third input terminal (i.e., terminal T1) of the control unit 3. The second end of the first resistor R1 is connected to the first end of the second resistor R2 and the first end of the inductor L1. The second end of the second resistor R2 is connected to the second end of the first capacitor C1 and grounded. The second end of the inductor L1 is connected to the first end of the thermistor RT1. The second end of the thermistor RT1 collects the supply voltage VCC.

[0039] Specifically, Figure 2 In this circuit, the resistance of RT1 changes with temperature, and together with R1 and L1, they form a voltage divider, converting the sensed temperature change into a stable voltage signal. This voltage signal is then filtered by R2 and C1 to obtain a smooth DC temperature signal, which is input to the control unit through the T1 terminal, thereby enabling the control unit to accurately monitor the temperature and determine over-temperature protection.

[0040] In some optional implementations, the voltage and current detection unit includes: a voltage sampling circuit and a current sampling circuit, wherein, for example... Figure 3 As shown, the input terminals (I1-1 and I1-2) of the current sampling circuit collect the current signal at the grid connection point, and the output terminals (Iout1-1 and Iout1-2) of the current sampling circuit are connected to the second input terminal of the control unit; as shown... Figure 4 As shown, the input terminals (i.e., U1-1 and U1-2) of the voltage sampling circuit collect the voltage signal at the grid connection point, and the output terminals (i.e., Uout1-1 and Uout1-2) of the voltage sampling circuit are connected to the first input terminal of the control unit.

[0041] Specifically, Figure 3 The current sampling circuit includes: a third resistor R3, a fourth resistor R4, a fifth resistor R5, a second capacitor C2, and a third capacitor C3. The first terminal of the third resistor R3 is connected to the first terminal of the fourth resistor R4 and the positive terminal of the public power grid at the grid connection point; the second terminal of the third resistor R3 is connected to the first terminal of the second capacitor C2 and the second input terminal of the control unit 3; the second terminal of the fourth resistor R4 is connected to the first terminal of the fifth resistor R5 and the negative terminal of the public power grid at the grid connection point; the second terminal of the fifth resistor R5 is connected to the first terminal of the third capacitor C3 and the second input terminal of the control unit 3; and the second terminal of the second capacitor C2 is connected to the second terminal of the third capacitor C3 and grounded.

[0042] Specifically, Figure 3In this circuit, R3 and R4 are connected in parallel to form a shunt network, which is connected between the positive and negative terminals of the power grid. This network proportionally converts the main circuit current flowing through the grid connection point into a weak differential voltage signal. This voltage signal is then processed by a symmetrical RC filter network composed of R5, C2, and C3. This network acts as a low-pass filter to effectively suppress high-frequency noise and switching interference, and significantly attenuates common-mode noise through its differential structure, thereby outputting a stable and clean current signal to the control unit.

[0043] Specifically, Figure 4 The voltage sampling circuit includes: a sixth resistor R6, a seventh resistor R7, an eighth resistor R8, a ninth resistor R9, a tenth resistor R10, an eleventh resistor R11, a twelfth resistor R12, a fourth capacitor C4, a fifth capacitor C5, and a voltage transformer T1. The first terminal of the seventh resistor R7 is connected to the positive terminal of the public power grid at the grid connection point, and the second terminal of the seventh resistor R7 is connected to the first terminal of the eighth resistor R8. The second terminal of the eighth resistor R8 is connected to the first terminal of the voltage transformer T1. The first terminal of the eleventh resistor R11 is connected to the negative terminal of the public power grid at the grid connection point, and the second terminal of the eleventh resistor R11 is connected to the first terminal of the twelfth resistor R12. The first terminal of resistor R12 is connected to the second terminal of voltage transformer T1; the first terminal of resistor R9 is connected to the first terminal of resistor R6 and the third terminal of voltage transformer T1; the second terminal of resistor R9 is connected to the first terminal of resistor R10 and the fourth terminal of voltage transformer T1; the second terminal of resistor R6 is connected to the first terminal of capacitor C4 and the first input terminal of control unit 3; the second terminal of resistor R10 is connected to the first terminal of capacitor C5 and the first input terminal of control unit 3; the second terminal of capacitor C4 is connected to the second terminal of capacitor C5 and grounded.

[0044] Specifically, Figure 4 In this circuit, resistors R7, R8, R11, and R12 form a symmetrical high-voltage divider network, significantly attenuating the grid voltage to the low-voltage range and providing current-limiting protection through series resistors. The divided signal drives the primary winding of voltage transformer T1, and electromagnetic isolation completely isolates the high-voltage side from the low-voltage control circuit, fundamentally eliminating the risk of high-voltage intrusion and ensuring system safety. The signal output from the secondary side of the voltage transformer is impedance matched by resistors R9 and R10, and then further conditioned by a differential low-pass filter network composed of resistors R6, C4, and C5. This network effectively suppresses high-frequency noise and common-mode interference, thereby outputting a pair of stable and clean differential voltage signals to the control unit.

[0045] Specifically, Figure 1Subsequently, the control unit performs synchronous sampling and digitization based on the current and voltage signals, utilizing its embedded high-performance analog-to-digital converter. By performing high-speed calculations on these two time-domain-aligned instantaneous voltage and current values, the real-time value and direction of the instantaneous active power at the grid connection point are calculated. When the calculation results indicate the presence of continuous active power flowing from the local distributed power source to the public grid, and its average or integral value exceeds the preset anti-reverse current threshold, the control unit determines that a power reverse current fault has occurred. Simultaneously, the control unit continuously monitors the temperature signal from the temperature detection unit. If this signal exceeds the set over-temperature protection threshold, it determines that the equipment is in an overheated state. For any of the above fault determinations, the control unit will immediately send a corresponding drive signal (such as a reverse current trip command or an over-temperature trip command) to the drive unit through its output terminal, thereby triggering subsequent protection action logic.

[0046] It should be noted that the software algorithm running within the control unit in this embodiment employs conventional signal processing and power calculation methods that are mature in the field, such as multiplication and accumulation operations based on instantaneous voltage and current sample values, zero-crossing comparison, and threshold judgment. That is, this embodiment only protects the specific structure of the anti-reverse current controller, and does not protect the calculation process and judgment methods of the control unit.

[0047] In some alternative implementations, such as Figure 5 As shown, the anti-reverse current controller also includes a voltage conversion unit 5, wherein the input terminal of the voltage conversion unit 5 receives the voltage of the public power grid, and the output terminal of the voltage conversion unit 5 outputs the supply voltage.

[0048] Specifically, Figure 6 The voltage conversion unit includes an input preprocessing circuit 51, a drive control circuit 52, and a voltage regulator circuit 53. The input terminal of the input preprocessing circuit 51 receives the voltage of the public power grid (i.e., V1-1 and V1-2), and the output terminal of the input preprocessing circuit 51 is connected to the input terminal of the drive control circuit 52. The input preprocessing circuit 51 is used to clamp and filter the voltage of the public power grid and output the preprocessed voltage. The output terminal of the drive control circuit 52 is connected to the input terminal of the voltage regulator circuit 53. The drive control circuit 52 is used to rectify and filter the preprocessed voltage and output the primary supply voltage. The voltage regulator circuit 53 is used to regulate the primary supply voltage and output the supply voltage VCC.

[0049] Optionally, Figure 5 In the process, the anti-reverse current controller also includes a display unit 6, wherein the control terminal of the display unit 6 is connected to the second output terminal of the control unit 3, and the display unit 6 is used to display the status information of the control unit 3, such as the parameter values ​​of voltage, current, power, temperature, etc. stored in the control unit, and the status information of the control unit.

[0050] This embodiment provides a circuit breaker for preventing backflow reclosing, such as... Figure 7 As shown, it includes: a housing, a circuit breaker body, and an anti-reverse current controller as described in the above embodiment. The anti-reverse current controller and the circuit breaker body are both integrated in the housing. The voltage input terminal of the voltage and current detection unit 1 in the anti-reverse current controller collects the voltage signal at the grid connection point of the public power grid through the second terminal of the circuit breaker body. The current input terminal of the voltage and current detection unit 1 collects the current signal at the grid connection point of the public power grid. The first terminal of the circuit breaker body is connected to the local distributed power source, and the control terminal of the circuit breaker body is connected to the output terminal of the drive unit 4 in the anti-reverse current controller.

[0051] Specifically, Figure 7 In this design, the voltage and current detection unit 1 of the anti-reverse current controller directly reuses the main circuit terminal (i.e., the second terminal) of the circuit breaker body as the voltage sampling point through internal electrical connections. It also utilizes an external current transformer to collect the current signal flowing through the power grid to the load near the grid, achieving direct and lag-free acquisition of the electrical status of the grid connection point. The operating mechanism (trip coil or motor) of the circuit breaker body is directly coupled to the drive unit of the anti-reverse current controller. When the control unit 3 determines power reverse current or detects over-temperature based on the sampled signal, it immediately controls the drive unit 4 to output drive energy to the circuit breaker's tripping system, triggering rapid tripping. This deep integration allows the entire chain from signal detection and intelligent processing to protection execution to be completed within a single housing. This not only completely eliminates all external connection lines and independent controllers, significantly improving system reliability, response speed, and environmental adaptability, but also makes the product a plug-and-play, field-configurable standardized protection unit, greatly simplifying the installation, commissioning, and maintenance process of distributed energy grid-connected systems.

[0052] The anti-backflow reclosing circuit breaker provided in this embodiment is an integrated reclosing device with intelligent anti-backflow protection capabilities. This device directly collects real-time electrical parameters of the grid connection point through an internally integrated voltage and current detection unit, and uses a built-in control unit to determine the power flow direction. When backflow is detected, it directly drives the circuit breaker's tripping mechanism to perform rapid tripping. This integrated design eliminates the external wiring, communication delays, and coordination costs associated with independent anti-backflow controllers and circuit breakers in traditional solutions. This not only greatly simplifies the system structure and reduces space requirements but also achieves extremely fast protection response speed due to the extremely short signal path, fundamentally eliminating the risk of instantaneous backflow exceeding limits caused by response delays. Simultaneously, the device retains the reclosing function, automatically restoring power supply after backflow elimination, achieving autonomous operation integrating detection, protection, and recovery, significantly improving the safety, reliability, and economy of distributed energy grid-connected systems.

[0053] This embodiment provides a photovoltaic system, such as Figure 8As shown, it includes: a photovoltaic power generation device and a reverse current reclosing circuit breaker according to the above embodiment, wherein the first end of the reverse current reclosing circuit breaker is connected to the photovoltaic power generation device, and the second end of the reverse current reclosing circuit breaker is connected to the public power grid.

[0054] Specifically, Figure 8 In this circuit breaker, the first terminal is directly connected to the output of the photovoltaic inverter, and the second terminal is connected to the power grid distribution point to collect the voltage and current at the grid connection point. During operation, the anti-reverse current controller integrated inside the circuit breaker continuously monitors the voltage and current at the grid connection point and calculates the balance between photovoltaic power generation and local load consumption in real time. Once it is detected that the photovoltaic power generation exceeds the local absorption capacity, forming active power fed back to the grid (i.e., reverse current) and reaching a set threshold, the built-in control unit will drive the circuit breaker to open within milliseconds, physically blocking the injection of reverse current into the grid and ensuring that the system strictly complies with the grid's anti-reverse current specifications. After the fault is cleared, the circuit breaker can automatically reclose to restore power supply.

[0055] The photovoltaic system provided in this embodiment integrates millisecond-level reverse current protection capabilities directly into key grid-connected nodes by building the system on top of an anti-reverse current reclosing circuit breaker. This circuit breaker, as the core protection unit of the system, monitors the balance between photovoltaic power generation and load demand in real time. It rapidly disconnects the grid connection the instant a potential reverse current flow occurs due to power surplus, physically blocking unauthorized power feeding and ensuring the power station strictly complies with grid anti-reverse current regulations. This solution replaces the complex combination of traditional controller-transformer-circuit breaker with a single integrated device, simplifying the system architecture, reducing construction and operation costs, and effectively ensuring the long-term compliant operation and revenue security of the photovoltaic power station by improving the real-time performance and reliability of protection.

[0056] Although embodiments of the present invention have been described in conjunction with the accompanying drawings, those skilled in the art can make various modifications and variations without departing from the spirit and scope of the present invention, and such modifications and variations all fall within the scope defined by the appended claims.

Claims

1. A backflow prevention controller, characterized in that, The anti-reverse current controller, applicable to grid-connected systems including public power grids and local distributed power sources, comprises: a control unit, a voltage and current detection unit, a temperature detection unit, and a drive unit, wherein... The input terminal of the voltage and current detection unit collects the voltage and current signals at the grid connection point of the public power grid, and the first output terminal and the second output terminal of the voltage and current detection unit are respectively connected to the first input terminal and the second input terminal of the control unit. The temperature detection unit acquires the temperature signal from the first terminal of the external switch unit at its input terminal, and the output terminal of the temperature detection unit is connected to the third input terminal of the control unit. The first output terminal of the control unit is connected to the control terminal of the drive unit. The control unit is used to calculate the power flow direction at the grid connection based on the voltage signal and the current signal, and output a first drive signal and a second drive signal based on the temperature signal when power reverse flow is detected. The output terminal of the drive unit is connected to the control terminal of the external switch unit. The first terminal of the external switch unit is connected to the local distributed power source, and the second terminal of the external switch unit is connected to the public power grid. The drive unit is used to control the on / off state of the external switch unit based on the first drive signal and the second drive signal, so as to control the local distributed power source and disconnect it from the grid. The control unit, voltage and current detection unit, temperature detection unit, drive unit, and external switch unit are encapsulated in the same housing.

2. The anti-backflow controller according to claim 1, characterized in that, The temperature detection unit includes: a first resistor, a second resistor, a first capacitor, an inductor, and a thermistor, wherein, The first end of the first resistor is connected to the first end of the first capacitor and the third input terminal of the control unit, and the second end of the first resistor is connected to the first end of the second resistor and the first end of the inductor. The second terminal of the second resistor is connected to the second terminal of the first capacitor and grounded; The second end of the inductor is connected to the first end of the temperature-sensitive resistor; The second terminal of the thermistor collects the power supply voltage.

3. The anti-backflow controller according to claim 1, characterized in that, The voltage and current detection unit includes: a voltage sampling circuit and a current sampling circuit, wherein... The input terminal of the voltage sampling circuit collects the voltage signal at the grid connection point, and the output terminal of the voltage sampling circuit is connected to the first input terminal of the control unit. The input terminal of the current sampling circuit collects the current signal at the grid connection point, and the output terminal of the current sampling circuit is connected to the second input terminal of the control unit.

4. The anti-backflow controller according to claim 3, characterized in that, The current sampling circuit includes: a third resistor, a fourth resistor, a fifth resistor, a second capacitor, and a third capacitor, wherein, The first end of the third resistor is connected to the first end of the fourth resistor and the positive terminal of the public power grid at the grid connection point; the second end of the third resistor is connected to the first end of the second capacitor and the second input terminal of the control unit. The second end of the fourth resistor is connected to the first end of the fifth resistor and the negative end of the public power grid at the grid connection point; The second end of the fifth resistor is connected to the first end of the third capacitor and the second input end of the control unit; The second terminal of the second capacitor is connected to the second terminal of the third capacitor and grounded.

5. The anti-backflow controller according to claim 3, characterized in that, The voltage sampling circuit includes: a sixth resistor, a seventh resistor, an eighth resistor, a ninth resistor, a tenth resistor, an eleventh resistor, a twelfth resistor, a fourth capacitor, a fifth capacitor, and a voltage transformer, wherein, The first end of the seventh resistor is connected to the positive end of the public power grid at the grid connection point, and the second end of the seventh resistor is connected to the first end of the eighth resistor; The second end of the eighth resistor is connected to the first end of the voltage transformer; The first end of the eleventh resistor is connected to the negative end of the public power grid at the grid connection point, and the second end of the eleventh resistor is connected to the first end of the twelfth resistor. The second terminal of the twelfth resistor is connected to the second terminal of the voltage transformer; The first end of the ninth resistor is connected to the first end of the sixth resistor and the third end of the voltage transformer, and the second end of the ninth resistor is connected to the first end of the tenth resistor and the fourth end of the voltage transformer. The second end of the sixth resistor is connected to the first end of the fourth capacitor and the first input end of the control unit; The second end of the tenth resistor is connected to the first end of the fifth capacitor and the first input end of the control unit; The second terminal of the fourth capacitor is connected to the second terminal of the fifth capacitor and grounded.

6. The anti-backflow controller according to claim 1, characterized in that, Also includes: Voltage conversion unit, wherein, The voltage of the public power grid is input to the input terminal of the voltage conversion unit, and the supply voltage is output to the output terminal of the voltage conversion unit.

7. The anti-backflow controller according to claim 6, characterized in that, The voltage conversion unit includes: an input preprocessing circuit, a drive control circuit, and a voltage regulation circuit, wherein... The input terminal of the input preprocessing circuit receives the voltage of the public power grid, and the output terminal of the input preprocessing circuit is connected to the input terminal of the drive control circuit. The input preprocessing circuit is used to clamp and filter the voltage of the public power grid and output the preprocessed voltage. The output terminal of the drive control circuit is connected to the input terminal of the voltage regulator circuit. The drive control circuit is used to rectify and filter the pre-processed voltage and output the primary power supply voltage. The voltage regulator circuit is used to regulate the primary supply voltage and then output the supply voltage.

8. The anti-backflow controller according to claim 1, characterized in that, Also includes: Display unit, wherein The control terminal of the display unit is connected to the second output terminal of the control unit, and the display unit is used to display the status information of the control unit.

9. A circuit breaker for preventing backflow reclosing, characterized in that, include: The housing, the circuit breaker body, and the anti-backflow controller according to any one of claims 1 to 8, wherein, The anti-reverse current controller and the circuit breaker body are both integrated in the housing. The voltage input terminal of the voltage and current detection unit in the anti-reverse current controller collects the voltage signal at the grid connection point of the public power grid through the second terminal of the circuit breaker body, and the current input terminal of the voltage and current detection unit collects the current signal at the grid connection point of the public power grid. The first end of the circuit breaker body is connected to the local distributed power supply, and the control end of the circuit breaker body is connected to the output end of the drive unit in the anti-reverse current controller.

10. A photovoltaic system, characterized in that, include: The photovoltaic power generation device and the anti-reverse current reclosing circuit breaker as described in claim 9, wherein, The first end of the anti-reverse current reclosing circuit breaker is connected to the photovoltaic power generation device, and the second end of the anti-reverse current reclosing circuit breaker is connected to the public power grid.

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