A centralized converter and voltage booster integrated device and a control method thereof

Abstract

This invention relates to the field of integrated converter and booster technology, and more particularly to a centralized integrated converter and booster device, comprising an integrated converter and booster used to convert and boost the electrical energy from a new energy power generation unit before connecting it to the power grid. The integrated converter and booster includes: a main unit, comprising a prefabricated cabin, the interior of which is divided by longitudinally arranged heat-insulating partitions into a power unit chamber, a transformer chamber, and a high-voltage chamber arranged sequentially along a first direction, the heat-insulating partitions being filled with phase change thermal storage material; a converter unit, located in the power unit chamber, comprising two power modules connected in parallel, the AC sides of the two power modules being converged by flexible laminated copper busbars to form the AC output terminal of the converter unit; through integrated layout, intelligent equalization control, online status monitoring, on-demand environmental regulation, and retractable hoisting design, it significantly improves space utilization, operational reliability, maintenance convenience, and grid fault ride-through capability.

Description

Technical Field

[0001] This invention relates to the field of integrated converter and boost converter technology, specifically to a centralized integrated converter and boost converter device and its control method. Background Technology

[0002] With the rapid development of new energy power generation technologies such as photovoltaic power generation and wind power generation, the installed capacity of new energy power plants is constantly expanding; the electrical energy generated by new energy power generation units needs to be converted and boosted before it can be connected to the power grid. According to CN221353687U, a centralized converter-boost integrated unit is disclosed. This technology discloses a technical solution including "a base, an installation plate on the top of the base, and the converter-boost integrated unit body on the top of the installation plate, with operating platforms on all four sides of the base". It has the following technical effects: "To meet the modular, integrated, and convenient design requirements of large-scale energy storage power stations, the converter-boost integrated unit body pre-installs the boost transformer, energy storage converter, high and low voltage power distribution unit, communication unit, etc. in a movable prefabricated cabin, providing an integrated "inverter" and "converter" product. It adopts an integrated design of converter and American-style box-type transformer, which can not only reduce the total investment cost of the system and improve the system efficiency, but also facilitates the overall hoisting, which is convenient and quick, greatly shortens the construction cycle of the power station, saves construction costs, reduces construction difficulty and uncontrollable risks, and enables the rapid construction of energy storage power stations." In existing centralized converter-boost integrated devices, during long-term operation, the actual junction temperature and output current of multiple power modules connected in parallel indoors vary due to differences in manufacturing processes, installation locations, and operating conditions. Some power modules operate under high loads for extended periods, while others operate under relatively low loads. This unbalanced operating state results in greater junction temperature fluctuations and faster aging rates in the power modules with higher loads. When these power modules fail prematurely due to overload, although the parallel structure can still maintain the device's operation, the remaining power modules need to bear even higher loads, further accelerating the aging process of the remaining power modules. Ultimately, this leads to the overall service life of the converter unit being far shorter than the design life of each power module, increasing the operation and maintenance costs and equipment replacement frequency of new energy power plants. Summary of the Invention

[0003] To address the shortcomings of existing technologies, this invention provides a centralized converter-boost integrated device and its control method. Through integrated layout, intelligent equalization control, online status monitoring, on-demand environmental regulation, and retractable hoisting design, it significantly improves space utilization, operational reliability, ease of operation and maintenance, and grid fault ride-through capability.

[0004] To achieve the above objectives, the present invention provides the following technical solution: a centralized converter-boost integrated device, comprising a converter-boost integrated unit for converting and boosting the electrical energy from a new energy power generation unit before connecting it to the power grid, the converter-boost integrated unit comprising: The main unit includes a prefabricated cabin, the interior of which is divided into a power unit chamber, a transformer chamber and a high voltage chamber arranged in sequence along the first direction by longitudinally arranged heat insulation partitions, and the interior of the heat insulation partitions is filled with phase change heat storage material. The converter unit, located in the power unit room, includes two power modules connected in parallel. The AC sides of the two power modules are collected through a flexible laminated copper busbar to form the AC output terminal of the converter unit. The step-up unit, located in the transformer room, includes a through-wall bushing assembly that penetrates and seals the heat insulation partition and a split-winding transformer. The first end of the through-wall bushing assembly is electrically connected to the AC output terminal of the converter unit, and its second end is electrically connected to the low-voltage side of the split-winding transformer. The high-voltage side of the split-winding transformer is used to output the stepped-up electrical energy. The high-voltage switch unit, located in the high-voltage room, includes a gas-insulated busbar and a switch body. One end of the gas-insulated busbar is electrically connected to the high-voltage side of the step-up unit, and the other end is electrically connected to the input end of the switch body. The output end of the switch body is used to connect to the power grid. An integrated monitoring unit is installed in the high-voltage room on the side near the high-voltage switch unit, and is connected to the converter unit, the step-up unit and the high-voltage switch unit for communication.

[0005] Preferably, the converter unit further includes: The module status monitoring array includes multiple temperature sensors and multiple current sensors respectively installed inside each power module; A ring-shaped communication fiber optic network connects the controllers of each power module in sequence into a ring topology and connects them to an integrated monitoring unit. The module equalization controller, integrated within the integrated monitoring unit, acquires real-time temperature and output current data of each power module through a ring-shaped fiber optic communication network. Based on a preset lifetime equalization algorithm, it calculates the real-time loss weight factor of each power module and dynamically adjusts the PWM carrier phase and modulation amplitude of each power module according to the loss weight factor.

[0006] The preferred through-wall sleeve assembly includes: The insulating sleeve body penetrates and is fixed to the heat insulation partition; The conductive rod is inserted inside the insulating sleeve body, with its two ends located in the power unit chamber and the transformer chamber, respectively; The first stress cone is located at the end of the conductive rod near the power unit chamber; The second stress cone is located at one end of the conductive rod near the transformer chamber; The shielding layer is located inside the insulating sleeve body and forms a capacitive voltage divider structure with the conductive rod. The shielding layer is connected to the integrated monitoring unit through lead terminals to collect the voltage signal on the conductive rod in real time.

[0007] Preferably, the gas-insulated busbar comprises: A metal enclosed shell filled with insulating gas; The center conductor is supported inside a metal enclosed shell by a basin-type insulator; The expansion joint structure is located in the middle of the metal enclosed shell and is used to absorb the relative displacement of the boost unit and the high-voltage switching unit caused by temperature changes. The displacement sensor is mechanically connected to the expansion joint structure and communicates with the integrated monitoring unit to monitor the expansion and contraction of the expansion joint structure in real time.

[0008] Preferably, the integrated converter and boost converter further includes an environmental control unit, comprising: The first heat exchanger is embedded in the wall of the corresponding power unit chamber; The second heat exchanger is embedded in the wall of the corresponding compartment of the transformer room; The shared compressor unit is located on the top outside of the prefabricated cabin and is connected to the first heat exchanger and the second heat exchanger respectively through refrigerant pipelines; An electric regulating valve assembly, located on the refrigerant pipeline and connected in communication with the integrated monitoring unit, is used to independently control the refrigerant flow to the first and second heat exchangers.

[0009] Preferably, the integrated converter and booster unit further includes a hoisting unit, comprising thickened seats fixed to the four upper corners inside the prefabricated cabin, with cylindrical cavities inside the thickened seats, springs installed at the lower ends of the cylindrical cavities, and protrusions fixed transversely through both ends of the cylindrical cavities. A column is slidably installed longitudinally inside the cylindrical cavities, with a lifting ring fixed at the upper end of the column. Longitudinal grooves are provided on the outer walls of both ends of the lifting rings, and transverse grooves communicating with the longitudinal grooves are provided at the upper ends of the longitudinal grooves.

[0010] Preferably, the hoisting unit further includes a sealing cover inserted into the upper part of the thickened seat, and the thickened seat has a buckle groove on both sides of the top.

[0011] This invention also discloses a control method for a centralized converter-boost integrated device, comprising the following steps: S1, the integrated monitoring unit collects grid voltage data and grid frequency data, and at the same time obtains the voltage signal of the through-wall bushing assembly through the lead terminal, and obtains the expansion and contraction data of the gas-insulated busbar through the displacement sensor; S2, the integrated monitoring unit determines whether a voltage drop has occurred in the power grid based on the power grid voltage data, and analyzes whether there is a risk of partial discharge in the wall bushing assembly based on the voltage signal, and analyzes whether there is a risk of excessive mechanical stress in the gas-insulated busbar based on the expansion and contraction data, and generates a risk coefficient based on the degree of partial discharge risk and the degree of excessive mechanical stress. S3, When it is determined that the power grid is in a voltage drop state, the integrated monitoring unit calculates the required reactive current target value based on the voltage drop depth of the power grid, calculates the frequency response component based on the power grid frequency deviation to correct the reactive current target value, and corrects the current limit value of the converter unit based on the risk coefficient. Then, it calculates the active current target value based on the corrected current limit value and the reactive current target value. S4, the converter unit generates a PWM drive signal based on the target values ​​of reactive current and active current, and corrects the carrier frequency of the PWM drive signal according to the risk coefficient, injecting reactive current into the grid to support the recovery of grid voltage; S5, during the period of grid voltage drop, the integrated monitoring unit continuously monitors the temperature of the boost unit and the DC bus voltage of the converter unit. When the temperature of the boost unit exceeds the first threshold or the DC bus voltage exceeds the second threshold, the required heat dissipation increment is calculated according to the degree of over-limit, and the opening of the electric regulating valve group is adjusted accordingly to increase the refrigerant flow to the corresponding heat exchanger.

[0012] This invention provides a centralized converter-boost integrated device and its control method. Compared with the prior art, it has the following advantages: 1. The power unit compartment, transformer compartment, and high-voltage compartment are sequentially separated by longitudinally arranged thermal insulation partitions within the prefabricated cabin. Phase change thermal storage material is filled inside the thermal insulation partitions to effectively suppress the mutual transfer of heat between the functional compartments. The converter unit adopts parallel-connected power modules with flexible laminated copper busbars, which improves system redundancy and reduces switch overvoltage stress. The boost unit is directly connected to the converter unit through a through-wall bushing assembly that penetrates the thermal insulation partition, shortening the low-voltage AC path. The split-winding transformer suppresses harmonic components. The high-voltage switch unit achieves a compact connection through gas-insulated busbars. The integrated monitoring unit centrally communicates with each unit, realizing real-time monitoring and unified scheduling of the entire plant's operating status.

[0013] 2. The through-wall bushing assembly forms a capacitive voltage divider structure with the conductive rod through an internal shielding layer, enabling online monitoring of the bushing insulation status and partial discharge early warning; the gas-insulated busbar absorbs the relative displacement caused by thermal expansion and contraction through an expansion joint structure, and works with a displacement sensor to monitor the mechanical stress status in real time, preventing structural damage caused by thermal stress; the environmental control unit achieves precise on-demand temperature control of the power unit room and transformer room through a shared compressor unit and independently adjustable electric regulating valve group, ensuring that the equipment operates within a suitable temperature range and avoiding energy waste.

[0014] 3. The hoisting unit, through a retractable lifting ring structure combined with springs, protrusions, and guide grooves, achieves the concealment and rapid deployment of the lifting points, solving the maintenance problem of replacing large equipment without a load-bearing point inside the cabin. The control method uses an integrated monitoring unit to collect grid data and equipment status signals in real time. When the grid drops, it calculates the target value of reactive current based on the drop depth and frequency deviation, and generates a risk coefficient based on the equipment health status to correct the current limit value and carrier frequency. At the same time, it links with the environmental control unit to enhance heat dissipation, achieving a deep integration of electrical control and mechanical condition monitoring. Attached Figure Description

[0015] Figure 1 This is a three-dimensional structural diagram of the present invention; Figure 2 This is a block diagram of the overall device in this invention; Figure 3 This is a block diagram of the method steps in this invention; Figure 4 This is a schematic diagram of the hoisting unit in this invention; Figure 5 This is a cross-sectional structural diagram of the hoisting unit in this invention; Figure 6 This is a schematic diagram of the column structure in this invention.

[0016] In the diagram: 1. Converter and booster integrated unit; 17. Lifting unit; 171. Thickened base; 172. Cylindrical cavity; 173. Spring; 174. Protrusion; 175. Sealing cover; 176. Clip groove; 177. Column; 178. Lifting ring; 179. Longitudinal groove; 1710. Transverse groove. Detailed Implementation

[0017] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. 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.

[0018] Please see Figure 1 - Figure 6 This invention provides a technical solution: a centralized converter-boost integrated device, comprising a converter-boost integrated unit for converting and boosting the electrical energy from a new energy power generation unit before connecting it to the power grid. The converter-boost integrated unit includes: The main unit includes a prefabricated cabin, the interior of which is divided into a power unit chamber, a transformer chamber and a high voltage chamber arranged in sequence along the first direction by longitudinally arranged heat insulation partitions, and the interior of the heat insulation partitions is filled with phase change heat storage material. The converter unit, located in the power unit room, includes two power modules connected in parallel. The AC sides of the two power modules are collected through a flexible laminated copper busbar to form the AC output terminal of the converter unit. The step-up unit, located in the transformer room, includes a through-wall bushing assembly that penetrates and seals the heat insulation partition and a split-winding transformer. The first end of the through-wall bushing assembly is electrically connected to the AC output terminal of the converter unit, and its second end is electrically connected to the low-voltage side of the split-winding transformer. The high-voltage side of the split-winding transformer is used to output the stepped-up electrical energy. The high-voltage switch unit, located in the high-voltage room, includes a gas-insulated busbar and a switch body. One end of the gas-insulated busbar is electrically connected to the high-voltage side of the step-up unit, and the other end is electrically connected to the input end of the switch body. The output end of the switch body is used to connect to the power grid. An integrated monitoring unit is installed in the high-voltage room on the side near the high-voltage switch unit, and is connected to the converter unit, the step-up unit and the high-voltage switch unit for communication.

[0019] In this implementation scheme, the integrated converter and booster unit arranges the power unit chamber, transformer chamber, and high-voltage chamber sequentially along the first direction through a prefabricated cabin of the main unit, and achieves physical isolation by longitudinally arranged heat insulation partitions. The phase change heat storage material filled inside the heat insulation partitions absorbs heat and undergoes a phase change when the temperature rises, and releases heat when the temperature drops, thereby inhibiting the mutual transfer of heat between the power unit chamber and the transformer chamber. The converter unit is located in the power unit chamber, and its two parallel-connected power modules convert the DC power input from the new energy power generation unit into AC power during operation. The AC sides of the two power modules are converged through flexible laminated copper busbars to form the AC output terminal of the converter unit. The parallel structure allows the other power module to continue operating when one power module fails. The low stray inductance characteristics of the flexible laminated copper busbars reduce the overvoltage stress during the switching process of the power modules. The booster unit is located in the transformer chamber, and the through-wall bushing assembly penetrates the heat insulation partition and is sealed to it. Its first end is connected to the converter unit. The AC output terminal is electrically connected, and its second terminal is electrically connected to the low-voltage side of the split-winding transformer. The split-winding transformer steps up the low-voltage AC to medium-high voltage AC and outputs it through its high-voltage side. The through-wall bushing assembly allows the AC output from the converter unit to directly pass through the heat insulation partition into the transformer room, shortening the low-voltage AC path. The two independent windings of the split-winding transformer suppress the harmonic components generated by the converter unit. The high-voltage switch unit is located in the high-voltage room. One end of the gas-insulated busbar is electrically connected to the high-voltage side of the step-up unit, and the other end is electrically connected to the input terminal of the switch body. The output terminal of the switch body is used to connect to the power grid. The stepped-up electrical energy is transmitted to the switch body through the gas-insulated busbar, and the switch body controls the grid connection. The integrated monitoring unit is located in the high-voltage room on the side close to the high-voltage switch unit. It is communicatively connected to the converter unit, the step-up unit, and the high-voltage switch unit, respectively, to collect the operating data of each unit in real time and issue control commands, realizing centralized monitoring of the converter-step-up integrated unit.

[0020] Specifically, the converter unit further includes: The module status monitoring array includes multiple temperature sensors and multiple current sensors respectively installed inside each power module; A ring-shaped communication fiber optic network connects the controllers of each power module in sequence into a ring topology and connects them to an integrated monitoring unit. The module equalization controller, integrated within the integrated monitoring unit, acquires real-time temperature and output current data of each power module through a ring-shaped fiber optic communication network. Based on a preset lifetime equalization algorithm, it calculates the real-time loss weight factor of each power module and dynamically adjusts the PWM carrier phase and modulation amplitude of each power module according to the loss weight factor.

[0021] In this embodiment, the converter unit collects real-time operating status data of each power module through a module status monitoring array. Multiple temperature sensors installed inside each power module monitor the real-time junction temperature, and multiple current sensors monitor the output current. A ring-shaped fiber optic communication network connects the controllers of each power module sequentially into a ring topology and connects to the integrated monitoring unit, forming a high-speed bidirectional communication loop. When any communication path in the ring-shaped fiber optic communication network is interrupted, data continues to be transmitted in the other direction, ensuring communication reliability. The module equalization controller is integrated within the integrated monitoring unit and acquires real-time temperature data and output current data of each power module through the ring-shaped fiber optic communication network. The system collects streaming data and calculates the real-time loss weight factor for each power module based on a preset lifespan balancing algorithm. This loss weight factor reflects the aging rate of each power module under the current operating conditions. The module balancing controller dynamically adjusts the PWM carrier phase and modulation amplitude of each power module according to the loss weight factor, so that the power module with a higher loss weight factor bears lower switching and conduction losses, and the power module with a lower loss weight factor bears higher switching and conduction losses. This makes the junction temperature fluctuation of each power module more consistent and the aging rate of each power module more balanced, avoiding premature failure due to long-term overload of individual power modules and extending the overall service life of the converter unit.

[0022] Specifically, the through-wall sleeve assembly includes: The insulating sleeve body penetrates and is fixed to the heat insulation partition; The conductive rod is inserted inside the insulating sleeve body, with its two ends located in the power unit chamber and the transformer chamber, respectively; The first stress cone is located at the end of the conductive rod near the power unit chamber; The second stress cone is located at one end of the conductive rod near the transformer chamber; The shielding layer is located inside the insulating sleeve body and forms a capacitive voltage divider structure with the conductive rod. The shielding layer is connected to the integrated monitoring unit through lead terminals to collect the voltage signal on the conductive rod in real time.

[0023] In this embodiment, the through-wall bushing assembly penetrates and is fixed to the heat insulation partition through the insulating bushing body, realizing the electrical connection and physical isolation between the power unit chamber and the transformer chamber; the conductive rod is inserted inside the insulating bushing body, with its two ends located in the power unit chamber and the transformer chamber respectively, serving as a channel for power transmission to introduce the AC power output from the converter unit from the power unit chamber into the transformer chamber; a first stress cone is located at the end of the conductive rod near the power unit chamber, and a second stress cone is located at the end of the conductive rod near the transformer chamber, with the two stress cones uniformly distributing electric fields to prevent partial discharge caused by electric field concentration at both ends of the conductive rod; shielding layer Located inside the insulating bushing body, it forms a capacitive voltage divider structure with the conductive rod. When the conductive rod carries high-voltage AC current, the shielding layer induces a voltage divider signal proportional to the voltage of the conductive rod. This signal is connected to the integrated monitoring unit through the lead terminals. The integrated monitoring unit collects the voltage waveform data on the conductive rod in real time based on this signal. When insulation degradation or partial discharge occurs inside the insulating bushing body, high-frequency harmonic components or abnormal amplitude fluctuations appear in the voltage signal of the conductive rod. The integrated monitoring unit analyzes the voltage signal characteristics to determine the insulation status of the through-wall bushing assembly, thereby realizing online monitoring and early warning of the healthy operation of the through-wall bushing assembly.

[0024] Specifically, the gas-insulated busbar includes: A metal enclosed shell filled with insulating gas; The center conductor is supported inside a metal enclosed shell by a basin-type insulator; The expansion joint structure is located in the middle of the metal enclosed shell and is used to absorb the relative displacement of the boost unit and the high-voltage switching unit caused by temperature changes. The displacement sensor is mechanically connected to the expansion joint structure and communicates with the integrated monitoring unit to monitor the expansion and contraction of the expansion joint structure in real time.

[0025] In this embodiment, the gas-insulated busbar achieves electrical insulation between the central conductor and the outer shell through insulating gas filling the metal enclosure, enabling safe transmission of high-voltage power within a compact space. The central conductor is supported inside the metal enclosure by basin-type insulators, which provide both mechanical support and electrical isolation. An expansion joint structure is located in the middle of the metal enclosure. When changes in ambient temperature or load current cause thermal expansion and contraction of the booster unit and the high-voltage switch unit, the expansion joint structure absorbs the relative displacement between them through elastic deformation, preventing cracking of the weld seam of the metal enclosure or breakage of the basin-type insulator due to thermal stress. A displacement sensor is mechanically connected to the expansion joint structure to monitor the expansion and contraction data of the expansion joint structure in real time and transmits this data to the integrated monitoring unit. The integrated monitoring unit determines the current mechanical stress state of the gas-insulated busbar based on the expansion and contraction data. When the expansion and contraction exceeds the normal range, it indicates abnormal displacement between the booster unit and the high-voltage switch unit. The integrated monitoring unit then issues a warning signal to prevent damage to the gas-insulated busbar structure due to accumulated mechanical stress.

[0026] Specifically, the integrated converter and boost converter also includes an environmental control unit, comprising: The first heat exchanger is embedded in the wall of the corresponding power unit chamber; The second heat exchanger is embedded in the wall of the corresponding compartment of the transformer room; The shared compressor unit is located on the top outside of the prefabricated cabin and is connected to the first heat exchanger and the second heat exchanger respectively through refrigerant pipelines; An electric regulating valve assembly, located on the refrigerant pipeline and connected in communication with the integrated monitoring unit, is used to independently control the refrigerant flow to the first and second heat exchangers.

[0027] In this embodiment, the environmental control unit generates refrigerant circulation power through a shared compressor unit. The compressor unit is located on the top outer side of the prefabricated cabin to prevent its operational vibration and heat from affecting the equipment inside the cabin. The first heat exchanger is embedded in the cabin wall corresponding to the power unit compartment, and the second heat exchanger is embedded in the cabin wall corresponding to the transformer compartment. The two heat exchangers independently regulate the temperature of the power unit compartment and the transformer compartment, respectively. An electric regulating valve group is located on the refrigerant pipeline and is communicatively connected to the integrated monitoring unit. Based on the real-time temperature requirements of the power unit compartment and the transformer compartment, the integrated monitoring unit sends opening control commands to the corresponding valves in the electric regulating valve group to independently regulate the flow to the first heat exchanger and the second heat exchanger. The refrigerant flow rate of the two heat exchangers; when the power module is running at high load, the heat generation in the power unit chamber increases, and the integrated monitoring unit increases the opening of the corresponding electric regulating valve, allowing more refrigerant to flow into the first heat exchanger to enhance heat dissipation; when the load of the split winding transformer is low, the heat generation in the transformer chamber decreases, and the integrated monitoring unit decreases the opening of the corresponding electric regulating valve to reduce the flow of refrigerant into the second heat exchanger and avoid overcooling; through the structure of shared compressor units but independent heat exchangers and independent flow regulation, the environmental control unit achieves on-demand precise temperature control of the power unit chamber and transformer chamber, ensuring that the equipment in each functional chamber operates within a suitable temperature range, and avoiding energy waste caused by unified control.

[0028] Specifically, the integrated converter and booster unit 1 also includes a hoisting unit 17, which includes thickened seats 171 fixed to the four corners of the upper part of the prefabricated cabin. The thickened seats 171 have cylindrical cavities 172 inside. A spring 173 is installed at the lower end of the cylindrical cavity 172. Both ends of the cylindrical cavity 172 are horizontally fixed with protrusions 174. A column 177 is longitudinally slidably installed inside the cylindrical cavity 172. A lifting ring 178 is fixed at the upper end of the column 177. Both ends of the lifting ring 178 have longitudinal grooves 179 on their outer walls. The upper end of the longitudinal groove 179 has a transverse groove 1710 connected to it.

[0029] In this embodiment, the hoisting unit 17 provides a bearing base through thickened seats 171 fixed at the four corners of the upper end inside the prefabricated cabin 111. The cylindrical cavity 172 inside the thickened seat 171 is used to accommodate the retractable lifting ring structure. The spring 173 installed at the lower end inside the cylindrical cavity 172 is in a compressed state when the lifting ring 178 is in the retracted state, providing auxiliary thrust for the lifting ring 178 to pop out. The protrusions 174 fixed laterally through both ends of the cylindrical cavity 172 cooperate with the longitudinal grooves 179 and the transverse grooves 1710 on the column 177 to form a guide and limiting mechanism. The column 177 is longitudinally slidably installed inside the cylindrical cavity 172, and the lifting ring 178 is fixed at its upper end. The longitudinal grooves 179 on the outer walls at both ends of the lifting ring 178 are slidably engaged with the protrusions 174. The transverse grooves 1710 on the upper end of the longitudinal grooves 179 are slidably engaged with the protrusions 174. 10 is connected to the longitudinal groove 179; when the column 177 extends upward, the protrusion 174 is located at the lower end of the longitudinal groove 179, and the column 177 slides upward along the longitudinal groove 179 until the protrusion 174 slides to the upper end of the longitudinal groove 179. At this time, the lifting ring 178 is rotated to make the protrusion 174 get into the transverse groove 1710, and the column 177 is locked in the extended state; when the column 177 is retracted downward, the lifting ring 178 is rotated in the opposite direction to make the protrusion 174 get out of the transverse groove 1710 and enter the upper end of the longitudinal groove 179. Under the action of pressure, the column 177 compresses the spring 173 and slides downward along the longitudinal groove 179 until the protrusion 174 is located at the end of the transverse groove 1710 away from the longitudinal groove 179. The column 177 is completely retracted into the cylindrical cavity 172, and the upper end surface of the lifting ring 178 is flush with the upper end surface of the thickened seat 171.

[0030] Specifically, the hoisting unit 17 also includes a sealing cover 175 inserted into the upper part of the thickened base 171, and the thickened base 171 has a buckle groove 176 on both sides of the top.

[0031] In this embodiment, the hoisting unit 17 seals the cylindrical cavity 172 by inserting a sealing cover 175 installed inside the upper part of the thickened base 171. The sealing cover 175 is connected to the thickened base 171 by an interference fit, which prevents dust, moisture or foreign objects from entering the cylindrical cavity 172 when not in operation, and avoids corrosion of the spring 173 or sliding jamming of the column 177. The buckle grooves 176 opened on both sides of the top of the thickened base 171 provide a force point for maintenance personnel to remove the sealing cover 175.

[0032] This invention also discloses a control method for a centralized converter-boost integrated device, comprising the following steps: S1, the integrated monitoring unit collects grid voltage data and grid frequency data, and at the same time obtains the voltage signal of the through-wall bushing assembly through the lead terminal, and obtains the expansion and contraction data of the gas-insulated busbar through the displacement sensor; S2, the integrated monitoring unit determines whether a voltage drop has occurred in the power grid based on the power grid voltage data, and analyzes whether there is a risk of partial discharge in the wall bushing assembly based on the voltage signal, and analyzes whether there is a risk of excessive mechanical stress in the gas-insulated busbar based on the expansion and contraction data, and generates a risk coefficient based on the degree of partial discharge risk and the degree of excessive mechanical stress. S3, When it is determined that the power grid is in a voltage drop state, the integrated monitoring unit calculates the required reactive current target value based on the voltage drop depth of the power grid, calculates the frequency response component based on the power grid frequency deviation to correct the reactive current target value, and corrects the current limit value of the converter unit based on the risk coefficient. Then, it calculates the active current target value based on the corrected current limit value and the reactive current target value. S4, the converter unit generates a PWM drive signal based on the target values ​​of reactive current and active current, and corrects the carrier frequency of the PWM drive signal according to the risk coefficient, injecting reactive current into the grid to support the recovery of grid voltage; S5, during the period of grid voltage drop, the integrated monitoring unit continuously monitors the temperature of the boost unit and the DC bus voltage of the converter unit. When the temperature of the boost unit exceeds the first threshold or the DC bus voltage exceeds the second threshold, the required heat dissipation increment is calculated according to the degree of over-limit, and the opening of the electric regulating valve group is adjusted accordingly to increase the refrigerant flow to the corresponding heat exchanger.

[0033] In this embodiment, the integrated monitoring unit collects grid voltage and frequency data in real time in step S1 to obtain the grid connection point's operating status. Simultaneously, it acquires the voltage signal of the conductive rod inside the through-wall bushing assembly through the lead terminals and obtains the expansion and contraction data of the gas-insulated busbar expansion joint structure through a displacement sensor, achieving multi-dimensional perception of the grid status and equipment health status. In step S2, the integrated monitoring unit determines whether a voltage drop has occurred in the grid based on the grid voltage data. It also analyzes whether there is a risk of partial discharge in the through-wall bushing assembly based on the voltage signal and whether there is a risk of excessive mechanical stress in the gas-insulated busbar based on the expansion and contraction data. A risk coefficient is generated based on the degree of partial discharge risk and the degree of excessive mechanical stress. In step S3, when the grid is determined to be in a voltage drop state, the integrated monitoring unit calculates the required reactive current target value based on the grid voltage drop depth, corrects the reactive current target value based on the frequency response component calculated according to the grid frequency deviation, and corrects the current limit value of the converter unit based on the risk coefficient. When there is a high risk in the through-wall bushing assembly or the gas-insulated busbar... The current limit value is reduced accordingly, and then the active current target value is calculated based on the corrected current limit value and the reactive current target value to ensure that the total current does not exceed the corrected limit value. In step S4, the converter unit generates a PWM drive signal based on the reactive current target value and the active current target value, and corrects the carrier frequency of the PWM drive signal according to the risk coefficient. When the risk is high, the carrier frequency is increased to reduce switching losses, so that the power module actively derated when there is a potential fault risk in the equipment. The converter unit injects reactive current into the grid to support the grid voltage recovery. In step S5, during the grid voltage drop, the integrated monitoring unit continuously monitors the temperature of the boost unit and the DC bus voltage of the converter unit. When the temperature of the boost unit exceeds the first threshold, it indicates that the split winding transformer is overheating. When the DC bus voltage exceeds the second threshold, it indicates that the DC side energy accumulation may endanger the power module. The integrated monitoring unit calculates the required heat dissipation increment according to the degree of over-limit and adjusts the opening of the electric regulating valve group accordingly to increase the refrigerant flow to the first heat exchanger or the second heat exchanger and enhance the heat dissipation of the power unit room or transformer room.

[0034] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.

[0035] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A centralized converter-boost integrated device, characterized in that: The converter-boost integrated unit (1) is used to convert and boost the electrical energy from the new energy power generation unit and connect it to the power grid. The converter-boost integrated unit (1) includes: The main unit includes a prefabricated cabin, the interior of which is divided into a power unit chamber, a transformer chamber and a high voltage chamber arranged in sequence along the first direction by longitudinally arranged heat insulation partitions, and the interior of the heat insulation partitions is filled with phase change heat storage material. The converter unit, located in the power unit room, includes two power modules connected in parallel. The AC sides of the two power modules are collected through a flexible laminated copper busbar to form the AC output terminal of the converter unit. The step-up unit, located in the transformer room, includes a through-wall bushing assembly that penetrates and seals the heat insulation partition and a split-winding transformer. The first end of the through-wall bushing assembly is electrically connected to the AC output terminal of the converter unit, and its second end is electrically connected to the low-voltage side of the split-winding transformer. The high-voltage side of the split-winding transformer is used to output the stepped-up electrical energy. The high-voltage switch unit, located in the high-voltage room, includes a gas-insulated busbar and a switch body. One end of the gas-insulated busbar is electrically connected to the high-voltage side of the step-up unit, and the other end is electrically connected to the input end of the switch body. The output end of the switch body is used to connect to the power grid. An integrated monitoring unit is installed in the high-voltage room on the side near the high-voltage switch unit, and is connected to the converter unit, the step-up unit and the high-voltage switch unit for communication.

2. The centralized converter-boost integrated device according to claim 1, characterized in that: The converter unit also includes: The module status monitoring array includes multiple temperature sensors and multiple current sensors respectively installed inside each power module; A ring-shaped communication fiber optic network connects the controllers of each power module in sequence into a ring topology and connects them to an integrated monitoring unit. The module equalization controller, integrated within the integrated monitoring unit, acquires real-time temperature and output current data of each power module through a ring-shaped fiber optic communication network. Based on a preset lifetime equalization algorithm, it calculates the real-time loss weight factor of each power module and dynamically adjusts the PWM carrier phase and modulation amplitude of each power module according to the loss weight factor.

3. The centralized converter-boost integrated device according to claim 1, characterized in that: The through-wall sleeve assembly includes: The insulating sleeve body penetrates and is fixed to the heat insulation partition; The conductive rod is inserted inside the insulating sleeve body, with its two ends located in the power unit chamber and the transformer chamber, respectively; The first stress cone is located at the end of the conductive rod near the power unit chamber; The second stress cone is located at one end of the conductive rod near the transformer chamber; The shielding layer is located inside the insulating sleeve body and forms a capacitive voltage divider structure with the conductive rod. The shielding layer is connected to the integrated monitoring unit through lead terminals to collect the voltage signal on the conductive rod in real time.

4. The centralized converter-boost integrated device according to claim 1, characterized in that: The gas-insulated busbar includes: A metal enclosed shell filled with insulating gas; The center conductor is supported inside a metal enclosed shell by a basin-type insulator; The expansion joint structure is located in the middle of the metal enclosed shell and is used to absorb the relative displacement of the boost unit and the high-voltage switching unit caused by temperature changes. The displacement sensor is mechanically connected to the expansion joint structure and communicates with the integrated monitoring unit to monitor the expansion and contraction of the expansion joint structure in real time.

5. The centralized converter-boost integrated device and its control method according to claim 1, characterized in that: The integrated converter and boost converter also includes an environmental control unit, comprising: The first heat exchanger is embedded in the wall of the corresponding power unit chamber; The second heat exchanger is embedded in the wall of the corresponding compartment of the transformer room; The shared compressor unit is located on the top outside of the prefabricated cabin and is connected to the first heat exchanger and the second heat exchanger respectively through refrigerant pipelines; An electric regulating valve assembly, located on the refrigerant pipeline and connected in communication with the integrated monitoring unit, is used to independently control the refrigerant flow to the first and second heat exchangers.

6. The centralized converter-boost integrated device according to claim 1, characterized in that: The converter booster integrated machine (1) also includes a hoisting unit (17), including a thickened seat (171) fixed at the four corners of the upper end of the prefabricated cabin. The thickened seat (171) has a cylindrical cavity (172) inside. A spring (173) is installed at the lower end of the cylindrical cavity (172). Both ends of the cylindrical cavity (172) are horizontally fixed with protrusions (174). A column (177) is longitudinally slidably installed inside the cylindrical cavity (172). A lifting ring (178) is fixed at the upper end of the column (177). Both ends of the lifting ring (178) have longitudinal grooves (179) on their outer walls. The upper end of the longitudinal groove (179) has a transverse groove (1710) connected to it.

7. A centralized converter-boost integrated device according to claim 6, characterized in that: The hoisting unit (17) also includes a sealing cover (175) inserted into the upper part of the thickened seat (171), and the thickened seat (171) has a buckle groove (176) on both sides of the top.

8. A control method for a centralized converter-boost integrated device, characterized in that: The centralized converter-boost integrated device according to any one of claims 1-7 includes the following steps: S1, the integrated monitoring unit collects grid voltage data and grid frequency data, and at the same time obtains the voltage signal of the through-wall bushing assembly through the lead terminal, and obtains the expansion and contraction data of the gas-insulated busbar through the displacement sensor; S2, the integrated monitoring unit determines whether a voltage drop has occurred in the power grid based on the power grid voltage data, and analyzes whether there is a risk of partial discharge in the wall bushing assembly based on the voltage signal, and analyzes whether there is a risk of excessive mechanical stress in the gas-insulated busbar based on the expansion and contraction data, and generates a risk coefficient based on the degree of partial discharge risk and the degree of excessive mechanical stress. S3, When it is determined that the power grid is in a voltage drop state, the integrated monitoring unit calculates the required reactive current target value based on the voltage drop depth of the power grid, calculates the frequency response component based on the power grid frequency deviation to correct the reactive current target value, and corrects the current limit value of the converter unit based on the risk coefficient. Then, it calculates the active current target value based on the corrected current limit value and the reactive current target value. S4, the converter unit generates a PWM drive signal based on the target values ​​of reactive current and active current, and corrects the carrier frequency of the PWM drive signal according to the risk coefficient, injecting reactive current into the grid to support the recovery of grid voltage; S5, during the period of grid voltage drop, the integrated monitoring unit continuously monitors the temperature of the boost unit and the DC bus voltage of the converter unit. When the temperature of the boost unit exceeds the first threshold or the DC bus voltage exceeds the second threshold, the required heat dissipation increment is calculated according to the degree of over-limit, and the opening of the electric regulating valve group is adjusted accordingly to increase the refrigerant flow to the corresponding heat exchanger.

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