A transformer for flywheel battery hybrid energy storage bidirectional conversion

Abstract

The utility model belongs to transformer technical field, concretely relates to a transformer for flywheel battery hybrid energy storage bidirectional conversion, including iron core, high voltage winding and low voltage winding, the low voltage winding adopts axial double distribution type structure, forms the first low voltage winding and the second low voltage winding of independent on circuit, symmetrical distribution on magnetic circuit, the high voltage winding is multistage radial layer structure, and adopts the folding reversal winding mode, and the winding layer is provided with insulating grid and forms honeycomb type ventilation air duct, the cross section of iron core is multistage ladder shape or optimization long circle, and its magnetic circuit joint adopts longitudinal seven step 45 degree full oblique joint structure, the high voltage winding is provided with electromagnetic shielding layer with low voltage winding, the utility model discloses through optimization design, material adopts, winding design and heat dissipation improvement etc. measure realizes the high -efficient energy -conserving target.

Description

Technical Field

[0001] This utility model belongs to the field of transformer technology, specifically relating to a transformer for bidirectional conversion of flywheel battery hybrid energy storage. Background Technology

[0002] In hybrid energy storage systems, flywheel energy storage excels in high power density, long lifespan, and fast response, while battery energy storage is superior in high energy density. Combining the two offers complementary advantages and represents a significant development direction in the current energy storage field. The core power conversion device connecting these two energy storage components is typically a bidirectional converter, and the transformer, as a key magnetic component, plays a crucial role in their performance.

[0003] Traditional transformer designs are used for power frequency, unidirectional power transmission. When applied to flywheel-battery hybrid energy storage systems, they face the following challenges: 1. Efficiency and Loss Issues: Increased Energy Conversion Losses: Traditional power frequency transformers introduce additional circuit losses during bidirectional energy conversion, resulting in high transformer losses. Inadequate traditional core materials and winding design structures lead to significant no-load and load losses, making it difficult to meet the high-efficiency and energy-saving requirements of new energy systems. Furthermore, inadequate local considerations in the electrical structure of the high-voltage winding result in relatively uneven distributed electric field effects, making partial discharge more likely.

[0004] Heat dissipation challenges: If the bidirectional converter and transformer are working, the high-frequency operation may lead to higher losses and heat generation, requiring additional heat dissipation design; the thermal conductivity of the dry-type epoxy resin casting process is insufficient, resulting in a high temperature rise and affecting long-term operational stability.

[0005] 2. Cost issues: High size and cost: Traditional transformers are usually large and heavy, which increases the physical space requirements and hardware costs of energy storage systems.

[0006] 3. Weak harmonic resistance: The grid-connected current of new energy sources contains harmonic components, and the traditional winding design parameters are prone to causing local overheating.

[0007] To address the aforementioned problems, this utility model proposes a transformer for bidirectional conversion of flywheel battery hybrid energy storage. Utility Model Content

[0008] The purpose of this invention is to provide a transformer for bidirectional conversion of flywheel battery hybrid energy storage, which achieves high efficiency and energy saving through optimized design, material selection, winding design and heat dissipation improvement.

[0009] The specific technical solution adopted by this utility model is as follows: A transformer for bidirectional conversion of flywheel battery hybrid energy storage includes an iron core, a high-voltage winding, and a low-voltage winding. The low-voltage winding adopts an axial double-split structure, forming a first low-voltage winding and a second low-voltage winding that are independent in the circuit and symmetrically distributed in the magnetic circuit. The high-voltage winding has a multi-segment radial layer structure and adopts a folded reverse winding method. Insulating grids are set between the winding layers to form a honeycomb ventilation channel. The cross-section of the iron core is a multi-step stepped shape or an optimized elongated oval shape, and its magnetic circuit joint adopts a longitudinal seven-step 45° full oblique joint structure. An electromagnetic shielding layer is provided between the high-voltage winding and the low-voltage winding.

[0010] Preferably, the core is made of low-loss silicon steel sheets, and its magnetic flux density is optimized to reduce no-load loss.

[0011] Preferably, the high-voltage winding is cast into a cylindrical shape by epoxy resin, the epoxy resin formula containing 30%-40% by mass of silica thermally conductive filler, and the cast winding has a pre-set axial through hole inside.

[0012] Preferably, an elastic silicone pad is provided between the iron core and the winding, and a rectangular shock absorber is installed on the transformer base.

[0013] Preferably, the voltage and capacity of the first low-voltage winding and the second low-voltage winding are the same, their total capacity is equal to the rated capacity of the transformer, and they can operate individually or in parallel.

[0014] The technical effects achieved by this utility model are as follows: In this invention, the high-voltage winding of the double-split transformer has a double-split structure, and the low-voltage winding is also split into two independent windings, which can be operated individually or in parallel to adapt to the different voltage requirements of flywheel energy storage and battery energy storage units.

[0015] This invention enables short-circuit current limiting by including through-impedance (impedance when low-voltage windings are connected in parallel), semi-through-impedance (impedance when a single branch is running), and split impedance (impedance between two branches). The split impedance is significantly higher than that of a conventional transformer to limit short-circuit current. This split winding structure effectively limits the short-circuit current on the low-voltage side, reduces the impact of faults, and improves system safety.

[0016] This invention boasts advantages of high stability and low loss. The independent magnetic circuit design of the split transformer reduces winding coupling, resulting in weaker magnetic coupling between the split windings. This ensures that each branch operates independently without affecting the others, and that other windings can still maintain normal power supply during faults. The overall design reduces structural losses; its low noise and low partial discharge characteristics, such as epoxy coating on the core end face, ensure long-term stable operation.

[0017] This invention boasts advantages in voltage adaptability; it supports multiple customized voltage outputs on the secondary side, such as 400V, to meet the voltage requirements of the flywheel and battery at different charging and discharging stages. Employing a symmetrical winding structure, it supports forward and reverse voltage conversion, adapting to the bidirectional energy flow requirements of energy storage systems. Optimized winding technology, using high-purity oxygen-free copper, and in conjunction with an intelligent control module, reduces energy loss, achieves high bidirectional conversion efficiency, and stably handles load fluctuations, ensuring efficient operation of the energy storage system.

[0018] This invention reduces no-load and load losses, improving energy efficiency in new energy scenarios. High-voltage coil heat dissipation structure: The double-split transformer uses a high-voltage coil body bonded into a cylindrical shape by insulating material, with several through holes to enhance directional ventilation, reduce internal airflow circulation and current stabilization phenomena, significantly improving heat dissipation performance. Optimizing the heat dissipation structure reduces temperature rise and improves long-term operational reliability.

[0019] In a flywheel-battery hybrid energy storage system, the low-voltage side of the transformer is divided into multiple branches, which can be connected to the plant busbar via external branch circuit breakers, and then grid-connected with the power electronic transformer units of the flywheel and battery, achieving flexible power supply and fault isolation for multiple energy storage units. This invention optimizes costs by optimizing the transformer design, reducing transformer size, and adapting to the compact requirements of new energy power plants. It has strong application adaptability. Hybrid energy storage synergy: In the flywheel and battery hybrid system, the double-split transformer, through flexible configuration of the low-voltage winding, balances the power transmission of both, improving frequency regulation performance. It optimizes the balance of the double-split magnetic circuit, reducing noise and vibration. It enhances harmonic resistance and reduces local overheating caused by current distortion. In the flywheel-battery hybrid energy storage system, the double-split transformer, through structural innovation and functional optimization, achieves efficient, safe, and flexible power conversion and transmission capabilities. Through multi-branch power supply and flexible voltage regulation, it effectively integrates the power demands of different energy storage units, while its heat dissipation optimization and fault isolation functions ensure the long-term stability of the system under high load or extreme conditions. Attached Figure Description

[0020] Figure 1 This is a front view of a transformer for bidirectional conversion of flywheel battery hybrid energy storage according to this utility model; Figure 2 This is a cross-sectional view of a transformer for bidirectional conversion of flywheel battery hybrid energy storage according to this utility model; Figure 3 This is the electrical operation principle diagram of the transformer for bidirectional conversion of flywheel battery hybrid energy storage according to this utility model.

[0021] In the diagram: 1. Iron core; 2. Low-voltage winding; 3. High-voltage winding. Detailed Implementation

[0022] To make the objectives and advantages of this utility model clearer, the following detailed description is provided in conjunction with embodiments. It should be understood that the following text is merely used to describe one or more specific embodiments of this utility model and does not strictly limit the scope of protection specifically claimed by this utility model.

[0023] like Figure 1 As shown, a transformer for bidirectional conversion of flywheel battery hybrid energy storage includes an iron core 1, a high-voltage winding 3, and a low-voltage winding 2. The low-voltage winding 2 adopts an axial double-split structure, forming a first low-voltage winding 2 and a second low-voltage winding 2 that are independent in the circuit and symmetrically distributed in the magnetic circuit. The high-voltage winding 3 has a multi-segment radial layer structure and adopts a folded reverse winding method. Insulating grids are set between the winding layers to form a honeycomb ventilation channel, which enhances heat dissipation and insulation strength. The cross-section of the core 1 is a multi-step stepped shape or an optimized oblong shape to reduce the additional losses caused by uneven magnetic flux distribution. Its magnetic circuit joint adopts a longitudinal seven-step 45° full oblique connection structure. The core 1 uses high-quality core 1 material (such as Shougang, or Baosteel Wuhan Iron and Steel, silicon steel R065 / 070), with a longitudinal seven-step 45° full oblique connection, and the magnetic flux density parameters are reasonably designed to reduce no-load loss by more than 20%-30%.

[0024] An electromagnetic shielding layer is provided between the high-voltage winding 3 and the low-voltage winding 2 to isolate and filter out harmonics.

[0025] Preferably, the core 1 is made of low-loss silicon steel sheet, and its magnetic flux density is optimized to reduce no-load loss.

[0026] Preferably, the high-voltage winding 3 is integrally cast into a cylindrical shape using epoxy resin. The epoxy resin formulation contains 30%-40% by weight of thermally conductive silica filler, and the cast winding has pre-set axial through holes, increasing the thermal conductivity to over 1.5 W / (m·K). A vacuum casting static process is employed to eliminate air bubbles, improve insulation strength, and reduce the risk of partial discharge. Vibration damping design: elastic silicone pads are placed between the core 1 and the winding, and rectangular vibration dampers are installed on the base, reducing noise to below 50dB.

[0027] Preferably, an elastic silicone pad is provided between the iron core 1 and the winding, and a rectangular shock absorber is installed on the transformer base.

[0028] Preferably, the first low-voltage winding 2 and the second low-voltage winding 2 have the same voltage and capacity, and their total capacity is equal to the rated capacity of the transformer, and they can operate individually or in parallel.

[0029] In this invention, the high-voltage winding 3 of the double-split transformer has a double-split structure, and the low-voltage winding 2 is also split into two independent windings, which can be operated individually or in parallel to adapt to the different voltage requirements of flywheel energy storage and battery energy storage units.

[0030] This invention enables short-circuit current limiting by including through-impedance (impedance when the two low-voltage windings are connected in parallel), semi-through-impedance (impedance when a single branch is running), and split impedance (impedance between two branches). The split impedance is significantly higher than that of a conventional transformer to limit short-circuit current. This split winding structure effectively limits the short-circuit current on the low-voltage side, reduces the impact of faults, and improves system safety.

[0031] This invention boasts advantages of high stability and low loss. The independent magnetic circuit design of the split transformer reduces winding coupling, resulting in weaker magnetic coupling between the split windings. This ensures that each branch operates independently without affecting the others, and that other windings can still maintain normal power supply during faults. The overall design reduces structural losses; its low noise and low partial discharge characteristics, such as epoxy coating on the core end face, ensure long-term stable operation.

[0032] This invention boasts advantages in voltage adaptability; it supports multiple customized voltage outputs on the secondary side, such as 400V, to meet the voltage requirements of the flywheel and battery at different charging and discharging stages. Employing a symmetrical winding structure, it supports forward and reverse voltage conversion, adapting to the bidirectional energy flow requirements of energy storage systems. Optimized winding technology, using high-purity oxygen-free copper, and in conjunction with an intelligent control module, reduces energy loss, achieves high bidirectional conversion efficiency, and stably handles load fluctuations, ensuring efficient operation of the energy storage system.

[0033] This invention reduces no-load and load losses, improving energy efficiency in new energy scenarios. High-voltage coil heat dissipation structure: The double-split transformer uses a high-voltage coil body bonded into a cylindrical shape by insulating material, with several through holes to enhance directional ventilation, reduce internal airflow circulation and current stabilization phenomena, significantly improving heat dissipation performance. Optimizing the heat dissipation structure reduces temperature rise and improves long-term operational reliability.

[0034] In the flywheel-battery hybrid energy storage system, the low-voltage side of the transformer is divided into multiple branches, which can be connected to the plant busbar via external branch circuit breakers, and then grid-connected with the power electronic transformer units of the flywheel and battery, realizing flexible power supply and fault isolation for multiple energy storage units. This invention optimizes costs by optimizing the transformer design, reducing transformer size, and adapting to the compact requirements of new energy power plants. It has strong application adaptability. Hybrid energy storage synergy: In the flywheel and battery hybrid system, the double-split transformer, through flexible configuration of the low-voltage winding 2, balances the power transmission of both, improving frequency regulation performance. It optimizes the balance of the double-split magnetic circuit, reducing noise and vibration. It enhances harmonic resistance and reduces local overheating caused by current distortion. In the flywheel-battery hybrid energy storage system, the double-split transformer, through structural innovation and functional optimization, achieves efficient, safe, and flexible power conversion and transmission capabilities. Through multi-branch power supply and flexible voltage regulation characteristics, it effectively integrates the power demands of different energy storage units, while its heat dissipation optimization and fault isolation functions ensure the long-term stability of the system under high load or extreme conditions.

[0035] The above description is merely a preferred embodiment of this utility model. It should be noted that those skilled in the art can make various improvements and modifications without departing from the principle of this utility model, and these improvements and modifications should also be considered within the scope of protection of this utility model. Structures, devices, and operating methods not specifically described or explained in this utility model, unless otherwise specified or limited, shall be implemented using conventional methods in the field.

Claims

1. A transformer for bidirectional conversion of flywheel battery hybrid energy storage, characterized in that: Including the iron core, high-voltage winding, and low-voltage winding, The low-voltage winding adopts an axial double-split structure, forming a first low-voltage winding and a second low-voltage winding that are independent in the circuit and symmetrically distributed in the magnetic circuit. The high-voltage winding has a multi-segment radial layer structure and adopts a folded reverse winding method. Insulating grids are set between the winding layers to form a honeycomb ventilation channel. The cross-section of the iron core is a multi-step stepped shape or an optimized elongated oval shape, and its magnetic circuit joint adopts a longitudinal seven-step 45° full oblique joint structure. An electromagnetic shielding layer is provided between the high-voltage winding and the low-voltage winding.

2. A transformer for bidirectional conversion of flywheel battery hybrid energy storage according to claim 1, characterized in that: The core is made of low-loss silicon steel sheets, and its magnetic flux density is optimized to reduce no-load loss.

3. A transformer for bidirectional conversion of flywheel battery hybrid energy storage according to claim 1, characterized in that: The high-voltage winding is cast into a cylindrical shape by epoxy resin. The epoxy resin formula contains 30%-40% by weight of silicon dioxide thermally conductive filler, and the cast winding has a pre-set axial through hole inside.

4. A transformer for bidirectional conversion of flywheel battery hybrid energy storage according to claim 1, characterized in that: An elastic silicone pad is provided between the iron core and the winding, and a rectangular shock absorber is installed on the transformer base.

5. A transformer for bidirectional conversion of flywheel battery hybrid energy storage according to claim 1, characterized in that: The first low-voltage winding and the second low-voltage winding have the same voltage and capacity, and their total capacity is equal to the rated capacity of the transformer. They can operate individually or in parallel.

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