A device design for terminal bidirectional voltage regulation

Abstract

The application relates to the field of low-voltage power distribution and power electronics, and discloses a design of a terminal bidirectional voltage regulating device, which comprises a bidirectional power voltage regulating module, a voltage sampling module, a control module, an automatic bypass module and a manual bypass module. The bidirectional voltage regulating device is connected in series in a low-voltage transformer area line, and can realize real-time bidirectional voltage regulation of the low-voltage line. The bidirectional voltage regulating device can be used for treating low-voltage problems at the terminal of the transformer area and can also be used for treating high-voltage problems at the terminal caused by photovoltaic grid connection. The automatic bypass module ensures that the device can realize seamless switching, and the device will not cause power failure of users on the low-voltage line when a fault occurs, thereby solving the problem that power failure of the transformer area occurs when the scheme is applied. The application has the advantages of compact structure, fast regulation response, wide application range, and can effectively solve the problems that the traditional low-voltage regulating device can only be regulated in one direction, has low voltage stabilization precision, cannot be regulated in real time, and will cause power failure of the low-voltage line when a fault occurs.

Description

Technical Field

[0001] This invention relates to the field of low-voltage power distribution technology, and in particular to a design for a bidirectional voltage regulating device at the end. Background Technology

[0002] With rapid economic growth in recent years and the booming development of urban villages and peri-urban areas, rural electricity load has surged. The contradiction between the power supply capacity of rural power distribution networks and the rapidly increasing electricity demand has become increasingly prominent, leading to frequent low-voltage problems that seriously affect users' normal electricity use and pose a severe challenge to power supply reliability. Furthermore, in remote mountainous areas, low-voltage problems are also increasing due to factors such as higher residential electricity consumption levels, excessively long power lines, and excessively thin power lines. Therefore, more and more end-user voltage regulating devices are being used to improve voltage for end users.

[0003] Conventional end-point voltage regulating devices employ a series voltage regulation scheme, which can only address low voltage at the end of a distribution area in one direction. However, with the increasing number of photovoltaic (PV) grid connections, more and more areas are experiencing high and low voltage distribution areas at the end due to PV grid connection. This design can effectively address this situation and solve the high voltage problem in the distribution area. Furthermore, series-connected devices have high reliability requirements because if the device malfunctions or requires maintenance, the power supply line must be disconnected before operation can proceed. This will cause power outages for downstream users, severely impacting their normal production and daily life. Especially in locations with high requirements for power continuity, such as hospitals, small processing plants, and important household power supplies, power outages not only cause economic losses but may also pose safety hazards. Therefore, how to ensure the normal voltage regulation function of the end-point bidirectional voltage regulating device while ensuring continuous power supply to downstream users when the device malfunctions or requires maintenance has become a critical issue that urgently needs to be addressed in the design of current end-point bidirectional voltage regulating devices. Traditional bypass designs often rely on relay-controlled contactor schemes, which have slow response speeds. Zero-crossing detection is required during bypassing, but due to the inconsistency of device parameters, the zero-crossing control effect is poor, and frequent switching of the contactor under load significantly reduces its lifespan. This automatic bypass module uses a combination of thyristors and relays to effectively bypass equipment malfunctions without affecting power supply to the end of the distribution area. Summary of the Invention

[0004] Based on this, in order to address the existing problems of low voltage and high voltage at the terminal, the present invention provides a design for a bidirectional voltage regulation device at the terminal.

[0005] The aforementioned bidirectional voltage regulating device enables bidirectional energy flow. It can address both low and high voltage issues at the end of a transformer substation.

[0006] The aforementioned end-point bidirectional voltage regulating device can achieve seamless switching through an automatic bypass module, solving the technical problem of power outages for end users caused by equipment failures in existing solutions.

[0007] The objective of this invention can be achieved through the following technical solutions.

[0008] A design for a bidirectional voltage regulation device at the end includes: a bidirectional power voltage regulation module, a voltage sampling module, a main control module, an automatic bypass module, and a manual bypass module.

[0009] Furthermore, the invention specifically includes the following steps:

[0010] S1, the terminal bidirectional voltage regulating device is connected in series to the low-voltage distribution area line and is located between the distribution area transformer and the end user;

[0011] S2, the input terminal of the voltage sampling module is connected to the input and output terminals of the bidirectional power voltage regulation module, and is also connected to the main control module;

[0012] S3, the main control module is connected to the voltage sampling module, the bidirectional power regulation module, and the automatic bypass module. The main control module has built-in overvoltage protection, overcurrent protection, and overheat protection functions. When the device triggers protection, the main control module sends signals to the bidirectional power regulation module and the automatic bypass module respectively, stopping the power regulation module from working and automatically switching to bypass mode;

[0013] S4, the automatic bypass module is connected in parallel with the bidirectional power voltage regulation module and the manual bypass module. After stabilization, it switches to the magnetic latching relay to continue bypassing, which can realize seamless uninterrupted power bypass at the end.

[0014] S5, the manual bypass module is connected to the input point and the output point of the device respectively, including an AC circuit breaker, and the manual bypass module is manually closed when the equipment needs maintenance.

[0015] S6, the voltage sampling module is used to detect the voltage values ​​of phase A, phase B, and phase C of the low-voltage side line of the distribution substation and the voltage values ​​of phase A, phase B, and phase C of the high-voltage side line of the device respectively. When the voltage value exceeds or falls below a set threshold, the voltage sampling module outputs a signal to the control module, and the control module outputs a control signal to the bidirectional power module to control the switching transistor PWM to adjust the output voltage in real time.

[0016] S7, the three phases of the aforementioned bidirectional power voltage regulation module can be decoupled and operated independently, and the output voltage of the three phases can be controlled by the main control module through the control signal issued.

[0017] S8, the aforementioned bidirectional voltage regulating device can be used for single-phase and three-phase lines. When a phase experiences low or high voltage, the voltage is detected by a voltage sampling module, allowing for real-time individual adjustment of the phase voltage. When the transformer area is within the normal range, it automatically exits the bidirectional voltage regulating module operation mode and switches to bypass mode to supply power to the terminal.

[0018] When the voltage is high at the end user, energy is transferred in the reverse direction, that is, from the end load to the distribution transformer to manage the high voltage at the end; when the voltage is low at the end user, energy is transferred in the forward direction, that is, from the distribution transformer to the end load to manage the low voltage at the end.

[0019] Beneficial technical effects of the present invention:

[0020] This invention enables bidirectional energy transmission through a bidirectional power module. In practical applications, it can address both low voltage at the end of the distribution network and high voltage at the end of the distribution area. The high voltage control function is primarily for distribution areas with grid-connected photovoltaic or other renewable energy sources, a scenario increasingly favored in recent years due to the country's strong emphasis on developing new energy sources. In practical applications, when voltage regulation is not required or equipment malfunctions, the automatic bypass module seamlessly switches to bypass mode, preventing power outages for end-users in the distribution area. This design effectively solves the problem of power outages caused by bypass switching in such solutions, significantly improving the reliability of power supply for users. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the end voltage regulating device for a single-phase line according to the present invention.

[0022] Figure 2 This is a schematic diagram of the automatic bypass module of the present invention.

[0023] Figure 3 This is a schematic diagram of the manual bypass module of the present invention.

[0024] Figure 4 This is a schematic diagram of the single-phase voltage sampling module of the present invention.

[0025] Figure 5 This is a schematic diagram of the end voltage regulating device of the three-phase line of the present invention.

[0026] Figure 6 This is a schematic diagram of the structure of the three-phase voltage sampling module of the present invention. Detailed Implementation

[0027] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to embodiments. It should be understood that the specific embodiments described herein are merely illustrative and do not limit the scope of the invention.

[0028] In one embodiment, see Figure 1 As shown, Figure 1 This is a schematic diagram of the structure of the bidirectional voltage regulation device at the end of a single-phase line according to the present invention. It mainly includes a bidirectional power voltage regulation module, a voltage sampling module, a main control module, an automatic bypass module, and a manual bypass module.

[0029] The aforementioned automatic bypass device, bidirectional power voltage regulation module, and manual bypass module are all connected in series in the circuit and in parallel. During normal voltage regulation, the bidirectional power voltage regulation module operates, while both the automatic and manual bypass modules are disconnected. When voltage regulation is not required or the device malfunctions, the bidirectional power voltage regulation module is disconnected, and the automatic bypass module is closed. When the device requires power-off detection, both the bidirectional power voltage regulation module and the automatic bypass module are disconnected, and the manual bypass module is closed.

[0030] The bidirectional voltage regulating device is connected in series to the low-voltage distribution area line and is located between the distribution transformer and the end user. The bidirectional power voltage regulating module, manual bypass module, and automatic bypass module are all connected in parallel to the power grid and are located between the distribution transformer and the end load user.

[0031] The input terminal of the voltage sampling module is connected to the input and output terminals of the bidirectional power voltage regulation module, and is also connected to the main control module.

[0032] The voltage sampling module detects the voltage value of the low-voltage side line of the distribution substation. When the voltage value exceeds or falls below a set threshold, the voltage sampling module outputs a signal to the main control module. The main control module outputs a control signal to the bidirectional power module to control the PWM duty cycle of the switching transistor to adjust the output voltage in real time.

[0033] When the bidirectional power module experiences overcurrent or overvoltage faults, the main control module transmits a signal to the automatic bypass module to close, and the bidirectional voltage regulator switches to bypass mode.

[0034] The bidirectional power module adjusts the output voltage according to the control signal from the main control module. The output voltage can reach 286V, and the output voltage is continuous with an accuracy error of less than 1%.

[0035] Reference Figure 2As shown, the automatic bypass module includes a thyristor and a magnetic latching relay. The thyristor and magnetic latching relay are connected in parallel, and then connected in series in the circuit. After the thyristor and magnetic latching relay are closed, the device enters the bypass state. Due to the excellent surge protection capability of the thyristor, the thyristor unit is controlled to close first before the magnetic latching relay unit closes, so that there is no voltage across the magnetic latching relay unit before the magnetic latching relay unit is controlled to close. At this time, there is no surge impact when the magnetic latching relay closes, which greatly improves the service life of the magnetic latching relay. Moreover, the short response time of the thyristor can complete the bypass switching within 1ms, without affecting the normal power supply of the end load users.

[0036] The automatic bypass module includes a thyristor and a magnetic latching relay. During bypass switching, leveraging the semiconductor characteristics of the thyristor and its fast response time (less than 1ms), the thyristor actuates first, followed by the magnetic latching relay closing. This ensures seamless bypass while protecting the magnetic latching relay from closing shocks, thus improving device reliability.

[0037] Reference Figure 3 As shown, the manual bypass module includes an AC circuit breaker, which is connected in series between the distribution transformer and the end load user.

[0038] The manual bypass module is disconnected when the bidirectional voltage regulator is running, and closed when manual maintenance of the device is required, without affecting the power supply to the end load.

[0039] Reference Figure 4 As shown, the voltage sampling module is connected to the input and output phases (L and N phases) of the device, and is also connected to the main control module.

[0040] The voltage sampling module measures the single-phase voltage of the L phase on the input side and the output side respectively, and transmits the collected voltage to the main control module. The main control module adjusts the output voltage of the bidirectional power module in real time based on the collected voltage of each phase.

[0041] When the voltage is high at the end user, energy is transferred in the reverse direction, that is, from the end load to the distribution transformer to manage the high voltage at the end; when the voltage is low at the end user, energy is transferred in the forward direction, that is, from the distribution transformer side to the end load to manage the low voltage at the end.

[0042] Reference Figure 5 As shown, the bidirectional end-of-phase voltage regulating device is applied in a three-phase scenario. It mainly includes a bidirectional power voltage regulating module, a voltage sampling module, a main control module, an automatic bypass module, and a manual bypass module.

[0043] The voltage sampling module is connected to the input and output phases A, B, C, and N of the device, and is also connected to the main control module.

[0044] The voltage sampling module measures the three-phase voltages (A-phase, B-phase, and C-phase) on both the input and output sides, and transmits the collected voltages to the main control module. The main control module then adjusts the output voltage of the bidirectional power module in real time based on the voltage collected from each phase.

[0045] When the voltage is high at the end user, energy is transferred in the reverse direction, that is, from the end load to the distribution transformer to manage the high voltage at the end; when the voltage is low at the end user, energy is transferred in the forward direction, that is, from the distribution transformer side to the end load to manage the low voltage at the end.

[0046] The three-phase voltage regulating device is independently decoupled in all three phases, and can intelligently adjust the phase voltage that needs to be adjusted.

[0047] The aforementioned bidirectional voltage regulator at the end of the circuit can be used in single-phase and three-phase lines. It adjusts the output voltage of the bidirectional power module in real time by detecting the input and output voltages. When the voltage is normal, the device switches to automatic bypass mode; when the voltage exceeds or falls below a threshold voltage, the device switches to normal operation mode and regulates the voltage in real time. During the switching between bypass and normal operation modes, fast-response semiconductor devices such as thyristors are used to achieve seamless switching without affecting the normal power supply to end users, thus solving the problem of power outages caused by bypassing such equipment. The bidirectional voltage regulator at the end of the circuit monitors the input and output voltages in real time, enabling bidirectional energy transfer based on the voltage conditions, thus managing both high and low voltage at end users.

[0048] This invention's terminal voltage regulating device can widely utilize mature components and equipment, has low loss, a compact structure, and is easy to transport, install, and maintain, making it suitable for long-term outdoor operation. This invention enables real-time voltage regulation, with intelligent and flexible regulation and a voltage regulation accuracy error of less than 1%. It can effectively solve the problems of low and high voltage at the terminal, truly achieving the effect of "solving big problems with small investment."

[0049] The above-described embodiments illustrate several implementation methods of the present invention, and are described in a relatively specific and detailed manner. However, they should not be construed as limiting the scope of the present invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these modifications and improvements all fall within the protection scope of the present invention. Therefore, the protection scope of the present invention should be determined by the appended claims.

Claims

1. A bidirectional voltage regulating device at the end, characterized in that, include: Two-way power voltage regulation module, voltage sampling module, control module, automatic bypass module, and manual bypass module.

2. The bidirectional voltage regulating device at the end according to claim 1, characterized in that, The bidirectional power voltage regulation module is connected in series between the low-voltage power grid and the load, and can realize bidirectional switching between forward boost voltage regulation and reverse buck voltage regulation according to the drive signal. The voltage regulation accuracy of the bidirectional power voltage regulation module reaches 1%.

3. The bidirectional voltage regulating device at the end according to claim 1, characterized in that, The bidirectional power regulation module is an AC / AC power supply module.

4. The bidirectional voltage regulating device at the end according to claim 1, characterized in that, The voltage sampling module is connected to the input terminal of the low-voltage power grid and the output terminal of the load, respectively, to collect the input voltage signal and the output voltage signal, and transmit the two voltage signals to the main control module.

5. The bidirectional voltage regulating device at the end according to claim 1, characterized in that, The automatic bypass module is connected in parallel with the bidirectional power voltage regulation module to the power grid, and includes a thyristor and a magnetic latching relay. When the device fails, the automatic bypass module operates to achieve seamless bypass switching.

6. The bidirectional voltage regulating device at the end according to claim 1, characterized in that, The manual bypass module is connected to the input and output sides of the bidirectional voltage regulator and consists of an AC circuit breaker. The manual bypass module is activated when the device needs to be manually powered off.

7. The bidirectional voltage regulating device at the end according to claim 1, characterized in that, The power voltage regulation module, automatic bypass module, and manual bypass module are three-phase modules.

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