High-power telescoped transformer

Abstract

To provide a high-power telescoped transformer that can be used to provide efficient power conversion in an electric vehicle (EV) fast charger.SOLUTION: The telescoped transformer includes a pair of concentric toroidal magnetic cores 400, 402, where a primary winding set consisting of long windings 404a and short windings 404b wraps around both cores, and where a secondary winding set 406 wraps around one of the cores. By using a shorter total length of wire for the windings, resistive power losses are reduced, compared with conventional transformer and inductance combinations. This also results in a reduced volume of the EV fast charger. Multiple transformer modules can be coupled in series to form a high-power EV charger.SELECTED DRAWING: Figure 6

Description

[Technical Field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS This patent application claims the benefit of U.S. patent application Ser. No. 18 / 613,846, filed Mar. 22, 2024, entitled "High Power Telescope Transformer," the entire contents of which are incorporated herein by reference.

[0002] The present disclosure relates to a power converter including a high frequency nested transformer suitable for use in electric vehicle (EV) charging stations. [Background technology]

[0003] Various types of electric vehicle charging stations have different voltage ratings and different charging speeds. Level 1 chargers plug into a standard 120V AC (alternating current) outlet and can charge an EV battery overnight. Level 2 chargers plug into a 240V AC outlet and can charge an EV battery in a few hours. Level 3 "fast" DC chargers are used in public charging stations and can charge an EV battery in less than an hour. Summary of the Invention

[0004] In some aspects, the technology described herein relates to an apparatus including a base toroidal outer core having an opening and a longitudinal axis passing through the opening; a base toroidal inner core disposed within the opening and coaxial with the base toroidal outer core; a first set of conductive windings wound around the base toroidal outer core and the base toroidal inner core and passing through the opening; and a second set of conductive windings wound around the base toroidal outer core and passing through the opening.

[0005] In some aspects, the techniques described herein relate to a device further including one or more additional toroidal outer cores stacked on top of the base toroidal outer core to form an outer cylinder having an opening, wherein the first and second sets of conductive windings are wound around the outer cylinder and pass through the opening.

[0006] In some aspects, the techniques described herein relate to an apparatus further including an additional toroidal inner core stacked on the base toroidal inner core to form an inner cylinder having an opening, wherein a first set of conductive windings is wound around the inner cylinder and passes through the opening.

[0007] In some aspects, the techniques described herein relate to an apparatus in which the outer cylinder is a transformer core and the inner cylinder is an inductance core.

[0008] In some aspects, the techniques described herein relate to an apparatus in which the second set of conductive windings is shorter than the first set of conductive windings by a length equal to approximately twice the radial thickness of the base toroidal inner core.

[0009] In some aspects, the techniques described herein relate to an apparatus in which the base toroidal outer core and the base toroidal inner core comprise a ferrite material.

[0010] In some aspects, the techniques described herein relate to devices in which the ferrite material comprises a zinc alloy.

[0011] In some aspects, techniques described herein relate to a method that includes energizing a primary winding of a nested transformer to induce a magnetic field in an outer transformer core and an inner inductor core, inducing a current in a secondary winding of the nested transformer via the magnetic field in the outer transformer core, and operating the nested transformer to supply power to an electric vehicle charger via the secondary winding.

[0012] In some aspects, the techniques described herein relate to a method in which operating the nested transformer includes energizing a long primary winding wound around both an outer transformer core and an inner inductor core.

[0013] In some aspects, techniques described herein relate to a method in which operating the nested transformer includes energizing a short primary winding wound around an outer transformer core.

[0014] In some aspects, the techniques described herein relate to methods whereby a power-to-volume ratio exceeds 10 kW / liter while operating a nested transformer.

[0015] In some aspects, the techniques described herein relate to an electric vehicle charging station that includes a power module including a printed circuit board; a nested transformer coupled to the printed circuit board, the nested transformer having an inner core within an outer core; a microcontroller mounted on the printed circuit board and coupled to the nested transformer, the microcontroller configured to control operation of the nested transformer; and a cable configured to couple the power module to the electric vehicle.

[0016] In some aspects, the techniques described herein relate to an EV charging station further including additional nested transformers coupled in parallel to increase the charging capacity of the electric vehicle charging station.

[0017] In some aspects, the techniques described herein relate to an electric vehicle charging station that further includes additional power modules coupled in parallel to increase the charging capacity of the electric vehicle charging station.

[0018] In some aspects, the techniques described herein relate to an electric vehicle charging station in which the power modules provide approximately 25 kW of power.

[0019] In some aspects, the techniques described herein relate to an electric vehicle charging station in which a nested transformer includes a stack of multiple toroidal outer magnetic cores.

[0020] In some aspects, the techniques described herein relate to electric vehicle charging stations in which a nested transformer has a substantially circular footprint on a printed circuit board.

[0021] In some aspects, the techniques described herein relate to electric vehicle charging stations that provide approximately 300 kW of total power.

[0022] In some aspects, the techniques described herein relate to electric vehicle charging stations in which the power modules include silicon carbide (SiC).

[0023] In some aspects, the techniques described herein relate to electric vehicle charging stations configured to operate at 240V. [Brief explanation of the drawings]

[0024] [Figure 1] 1 is a diagram of an electric vehicle (EV) fast charging station including a high-power nested transformer according to an implementation of the present disclosure. [Figure 2A] FIG. 1 is a perspective view of a transformer module according to an implementation of the present disclosure. [Figure 2B] FIG. 1 is a block diagram of a modular EV fast charger according to an implementation of the present disclosure. [Figure 3] 1A and 1B are top plan views of an AC-DC converter circuit board and a DC-DC converter circuit board to which a high-power nested transformer is coupled, according to an implementation of the present disclosure. [Figure 4] FIG. 1 is a perspective view of a high-power nested transformer according to an implementation of the present disclosure. [Figure 5] FIG. 1 is a flow diagram illustrating a method for operating a high-power nested transformer according to one implementation of the present disclosure. [Figure 6] FIG. 1 is a schematic diagram of a high-power nested transformer according to an implementation of the present disclosure. [Figure 7] FIG. 10 is a cross-sectional view of a high-power nested transformer during a short-circuit simulation in accordance with an implementation of the present disclosure. [Figure 8] FIG. 1 illustrates a cross-sectional view of a high-power nested transformer during an open-circuit simulation in accordance with an implementation of the present disclosure.

[0025] Aspects of the present disclosure are best understood from the following detailed description when read in conjunction with the accompanying drawings. It should be noted that, according to common practice in the industry, various features are not necessarily drawn to scale. Dimensions of various features may be arbitrarily increased or decreased for clarity of illustration. In the drawings, the same reference numerals may indicate the same and / or similar components (elements, structures, etc.) in different views. The drawings generally illustrate various implementations discussed in the present disclosure, by way of example, and not by way of limitation. Reference numerals shown in one drawing may not be repeated for the same and / or similar elements in associated figures. Reference numerals that are repeated in multiple drawings may not be specifically discussed with respect to each of those drawings, but are provided for context between the associated figures. Also, when multiple examples of an element are shown, not all of the same elements in the drawings are specifically referred to with a single reference numeral. DETAILED DESCRIPTION OF THE INVENTION

[0026] Most EV batteries in use today are rated at 400V DC (direct current). When using AC (alternating current) power, an AC-DC converter can be provided in the charger, or an internal AC-DC converter in the EV can be used. A DC-DC power converter can be provided, for example, in a fast charger to convert the high voltage (e.g., 480V DC) provided by the charging station to a lower voltage (e.g., 400V) that matches the rating of the EV battery being charged. DC-DC power converters are also used in many industrial applications, such as power supplies for internet servers and solid-state transformers.

[0027] An isolated DC-DC power converter can include an on-board high-frequency transformer with additional integrated inductance. The high-frequency transformer can operate in the range of approximately 100 kHz to approximately 300 kHz. The transformer is formed by winding a primary conductor and a secondary conductor around a common magnetic core to form a coil. When a time-varying signal is applied to either the primary or secondary conductor, a current is induced in the other conductor due to magnetic coupling. To increase the efficiency of the power converter, it is advantageous to increase the inductance of the transformer while reducing resistive losses in the coil. The inductance of a cylindrical coil is L = μN. 2 A / l, where μ is the permeability of the magnetic core, N is the number of turns in the coil, and A is given by πr 2 where ρ is the area of ​​the coil, and l is the length of the coil. Therefore, the inductance L of a transformer can be increased by increasing the number of turns or by increasing the radius of the core to increase the strength of the magnetic field. The resistance in a transformer coil winding is given by R = ρl / A, where ρ is the resistivity of the winding material, l is the length of the winding, and A is the cross-sectional area of ​​the wire used in the winding. Therefore, the resistance of a winding can be reduced by reducing the length of the wire used in the winding and by using a low-resistivity material for the winding, such as copper.

[0028] When losses in a transformer are primarily driven by core losses, e.g., for low- to medium-power magnets below approximately 10 kW, the transformer can be made more efficient by increasing the core's equivalent magnetic area and / or increasing the number of windings. When losses in a transformer are primarily driven by winding losses, e.g., for high-power magnets used in EV chargers, the transformer can be made more efficient by increasing the core's size (e.g., radius) and decreasing the number of windings, e.g., number of turns N (thereby decreasing winding length l). One way to effectively increase the core's equivalent magnetic area is to use the same winding to excite two magnetic cores. One geometry that supports such a design is the toroidal transformer, in which two or more magnetic cores are stacked on top of each other to increase the cross-sectional area and therefore the effective magnetic area.

[0029] DC-DC converter topologies, such as dual active bridge or resonant LLC converters, include two magnetic components: a transformer to provide galvanic isolation and voltage conversion, and an additional inductance to limit power flow between the two sides of the transformer. Each of these magnetic components has its own winding. By nesting two toroidal cores, some or all of the windings of one toroidal core can be wound around the other toroidal core. This reduces the overall length of the windings compared to using two separate magnetic components.

[0030] FIG. 1 is a perspective view of an EV charging station 100 according to some implementations of the present disclosure. The EV charging station 100 includes one or more EV fast chargers 102 (nine are shown in this example). In some implementations, the EV fast chargers 102 are public-use Level 3 chargers capable of charging an EV battery to approximately 80% capacity in approximately 30 minutes. In some implementations, the one or more EV fast chargers 102 can be located indoors in a parking garage, adjacent to an outdoor parking space, or at a designated EV charging station, e.g., an EV charging station 100 similar to a gas station for fuel vehicles. Each of the EV fast chargers 102 shown in FIG. 1 supports three charging cables 104. Internal components of the EV fast charger 102 include a transformer module 106 that can step down the voltage of a high-power supply powering the EV fast charger 102 to the voltage of a load, e.g., an EV battery.

[0031] FIG. 2A is a perspective view of a transformer module 106 in an EV fast charger 102 according to some implementations of the present disclosure. In some implementations, the transformer module 106 may be in the form of a double-decker printed circuit board (PCB) including an upper circuit board 200 (e.g., an upper PCB) and a lower circuit board 202 (e.g., a lower PCB). The upper circuit board 200 may be attached to the lower circuit board 202 by support posts 204. In some implementations, the upper circuit board 200 may include, among other components, one or more inductors 205 (three are shown). In some implementations, the lower circuit board 202 may include a single high-power nested transformer 206 (shown in FIGS. 2A and 3). In some implementations, one or more microprocessors 208 in the transformer module 106 may be used to control power delivery to the inductors 205 and the high-power nested transformer 206. The inductor 205 can be mounted to the upper circuit board 200 using a mounting plate 210 adjacent to heat sinks 212 (three shown). In some implementations, the high-power nested transformer 206 can be mounted to one or more heat sinks 212 (two shown) and electrically connected to the lower circuit board 202. In some implementations, the mounting plate 210 can act to dissipate heat and / or conduct heat to the heat sinks 212.

[0032] 2B is a block diagram of an EV fast charger 102 according to some implementations of the present disclosure. In some implementations, multiple transformer modules 106 can be used as building blocks that, when combined, can provide a desired total power delivery level for the EV fast charger 102. In some implementations, for example, each transformer module 106 can be a silicon carbide (SiC)-based 25 kW DC fast charger. When 12 such transformer modules 106 are used together, e.g., coupled in parallel, they can supply a total of 300 kW of DC power to the EV fast charger 102. The transformer modules 106 can operate within a frequency range of approximately 225 kHz to approximately 275 kHz.

[0033] Figure 3 shows further details of the transformer module 106 according to some implementations of the present disclosure. In Figure 3, an upper circuit board 200 and a lower circuit board 202 are shown arranged side by side. The left side of Figure 3 shows a top view of the upper circuit board 200 within the transformer module 106, and in the illustrated example, an inductor 205 is mounted to the upper circuit board. The right side of Figure 3 shows a top view of the lower circuit board 202 within the transformer module 106, to which a nested transformer 206 is mounted.

[0034] One high-power nested transformer 206 and corresponding microprocessor 208 (four shown) are shown as components of the lower circuit board 202 of the transformer module 106. In some implementations, a different number of high-power transformers 206 can be incorporated into the transformer module 106. If the operating current supplied to the high-power nested transformer 206 is too high, the magnetic material in the core of the high-power nested transformer 206 may saturate, causing the EV fast charger 102 to malfunction. The microprocessor 208 may be implemented as a microcontroller that controls semiconductor switches to limit the operating current so that the desired power is supplied to the nested transformer 206. This ensures safe operation of the high-power nested transformer 206. The high-power nested transformer 206 may be coupled to the lower circuit board 202 adjacent to a heat sink 212. In some implementations, each high-power nested transformer 206 has a substantially circular footprint and extends approximately 100 cm above the lower circuit board 200. 2 occupies a surface area of

[0035] In some implementations, the transformer module 106 is a power integration module in which the upper circuit board 200 functions as an AC / DC power converter and the lower circuit board 202 functions as a DC / DC power converter. The upper circuit board 200 includes an AC input port 300 and a DC output port 302. In some implementations, the upper circuit board 200 can receive an AC input of, for example, 480 V at the AC input port 300 and provide a DC output voltage of 800 V at the DC output port 302.

[0036] In some implementations, the lower circuit board 202 is a DC / DC power converter having a DC input port 304 and a DC output port 306. The lower circuit board 202 can receive 800V DC as an input from the upper circuit board 200 at the DC input port 304. The lower circuit board 202 can then provide a DC output voltage in the range of approximately 150V to 1000V at the DC output port 306. Standard EV batteries are rated at 400V, although some newer models have been developed with 800V capacities. Thus, the transformer module 106 can provide a range of voltages to accommodate different battery designs.

[0037] FIG. 4 is a perspective view of a high-power nested transformer 206 according to some implementations of the present disclosure. In some implementations, the high-power nested transformer 206 has a toroidal structure including an inductor core 400 nested within a transformer core 402. The inductor core 400 and the transformer core 402 may be formed from a ferrite material for high-frequency operation. In some implementations, the transformer core 402 may include, for example, a nickel-zinc (NiZn) or manganese-zinc (MnZn) solid ferrite core. The inductor core 400 may be a distributed gap core, which is less pure and magnetically weaker than the transformer core 402. The inductor core 400 is an inner toroidal magnetic core, and the transformer core 402 is an outer toroidal magnetic core. The inductor core 400 and the transformer core 402 are separated by a gap 403. In some implementations, the transformer core 402 can be in the form of a stack of multiple toroidal outer magnetic cores (four shown: 402a, 402b, 402c, and 402d), with the outer toroidal magnetic core 402d being the base outer toroidal magnetic core and the outer toroidal magnetic cores 402a, 402b, and 402c being stacked on top of the base outer toroidal magnetic core 402d. In some implementations, the inductor core 400 can also be formed from a base toroidal inductor core and multiple segments stacked on top of the base toroidal inductor core, similar to the laminated elements of the transformer core 402.

[0038] The inductance core 400 and the transformer core 402 form a concentric cylinder with a central opening 405 coaxial with a central longitudinal axis Z-Z'. The central longitudinal axis Z-Z' extends through the central opening 405. The empty volume inside the toroidal structure of the high-power nested transformer 206, for example, within the central opening 405, is used for stray / resonant inductance, resulting in a smaller volume occupied by magnetic components. Using a nested structure, the volume of the high-power nested transformer 206 can be minimized to a volume of approximately 0.8 liters. In some implementations, the outer radius of the transformer core 402 can be approximately 50 mm, corresponding to a diameter of approximately 10 cm. The corresponding power-to-volume ratio can be in the range of approximately 10 kW / liter to approximately 20 kW / liter.

[0039] The high-power nested transformer 206 further includes a primary winding set 404 and a secondary winding set 406. The primary winding set 404 includes several long windings 404a wound around both the inner cylinder forming the inductor core 400 and the outer cylinder forming the transformer core 402, passing through a central opening 405. The primary winding set 404 also includes several short windings 404b wound only around the transformer core 402 and not around the inductor core 400. In some implementations, it may be sufficient for some but not all of the turns of the primary winding set 404, e.g., winding 404a, to be wound around both magnetic cores, as shown in FIG. 4. For example, in FIG. 4, the number of long windings 404a is approximately equal to the number of short windings 404b, which is approximately equal to the number of turns of the secondary winding set 406. In some implementations, the primary winding set 404 can have a different ratio between the number of long windings 404a wound around both magnetic cores and the number of short windings 404b wound around one magnetic core than shown in this example. This ratio affects both the inductance of the high-power nested transformer 206 and the length of wire used for the primary winding set 404, which affects power loss. In some implementations, the total number of turns of the primary winding set 404, including both the long windings 404a and the short windings 404b, can be approximately twice the number of turns of the secondary winding set 406, as in the example shown in FIG. 4. As a result, in such implementations, the length of wire used for the primary winding set is more than twice the length of wire used for the secondary winding set due to the different lengths of the short windings 404b and the long windings 404a. In some implementations, the number of turns of the long windings 404b can be different from the number of turns of the short windings 404b. In general, without limitation, there may be any number of long windings 404a, any number of short windings 404b, and any number of turns in the secondary winding set 406. Furthermore, the windings are not limited to the exemplary order shown in FIG.

[0040] The geometry of the cylinder, for example, the radius of each magnetic core and the gap 403 between the inductance core 400 and the transformer core 402, also determines the length of wire required for the primary winding set 404 and the secondary winding set 406. Therefore, the particular nesting geometry also affects the resistive losses and therefore the efficiency of the EV fast charger 102.

[0041] The secondary winding set 406 is wound around the outer cylinder forming the transformer core 402 and passes through the gap 403 as shown. In some implementations, rather than winding around both magnetic cores, the secondary winding set 406 can be wound around the inner cylinder forming the inductance core 400 and pass through the central opening 405. In the example shown in FIG. 4, the secondary winding sets 406 are evenly distributed among the primary winding sets 404. However, this distribution or ordering of the windings is arbitrary. For example, all of the secondary winding sets 406 can be on one side of the toroidal structure of the high-power nested transformer 206, while all of the primary winding sets 404 can be on the other side of the toroidal structure. Any configuration can be used as long as the primary and secondary winding sets are not electrically or physically connected to each other. Coupling between the primary winding set 404 and the secondary winding set 406 occurs through magnetic induction in the transformer core.

[0042] In some implementations, the primary winding set 404 and / or the secondary winding set 406 can be copper windings. In some implementations, the inner diameter of the transformer core 402 can have a dimension that allows the inductance core 400 to fit inside the transformer core 402 with a gap 403 sufficient to accommodate the windings.

[0043] Each individual turn of the long primary winding set 404a is approximately 2l longer than the turns of the short primary winding set 404b and the turns of the secondary winding set 406, where 1 is the radial thickness of the inductance core 400. Because only a portion of the primary winding set 404 (e.g., the long winding 404a) is wound around both magnetic cores, and because of its compact construction, the high-power nested transformer 206 requires less wire for the windings than would be required with two separate components as shown in Figure 3. Less wire results in less resistive losses and, therefore, a more efficient transformer.

[0044] Although both primary winding set 404 and secondary winding set 406 are shown as having rectangular profiles, in some implementations, the winding profile can have another shape. For example, the winding profile can be circular. That is, individual windings 404a, 404b, and / or 406 can have rounded edges, and the winding turns need not be rectangular or have corners at the top and bottom of each turn, as shown in the example of FIG. 4. Instead, the winding turns can be curved, as shown, for example, in FIG. 6.

[0045] FIG. 5 is a flowchart illustrating a method 500 for operating a nested transformer, such as the high-power nested transformer 206, according to some implementations of the present disclosure described herein with reference to FIGS. 1-4 and 6-8. Operations 502-506 of method 500 may be performed to improve the efficiency of a high-power fast EV charger, such as the EV charger 102, according to some implementations. The operations of method 500 may be performed in a different order, or not at all, depending on the particular application. It should be noted that method 500 may not be the only way to operate the high-power nested transformer 206. Accordingly, it should be understood that additional processes may be provided before, during, or after method 500, and that some of these additional processes may be briefly described herein.

[0046] At 502, the method 500 includes energizing the primary winding set 404 according to some implementations of the present disclosure, as shown and described with reference to Figure 6. Because the primary winding set 404 is wound around both of the magnetic cores, applying a voltage to the primary winding set 404 induces a magnetic field in both the inductance core 400 and the transformer core 402.

[0047] 6 is a schematic diagram of a high-power nested transformer 206 according to some implementations of the present disclosure. FIG. 6 shows an inductance core 400 surrounded by a transformer core 402. In some implementations, as shown in FIG. One or both of the inductance core 400 and the transformer core 402 may be in the form of laminated elements (e.g., 402a, 402b, 402c, and 402d). For purposes of illustration, FIG. 6 appears to show only one such laminated element. However, items 400 and 402 in FIG. 6 are intended to represent any solid or laminated structure of nested magnetic cores. FIG. 6 also shows a secondary winding set 406 wound around the transformer core 402 and a portion of the primary winding set 404a wound around both the inductance core 400 and the transformer core 402. In some implementations, as shown in FIG. 6, some of the turns of the primary winding set 404, e.g., the long winding 404a, may be wound around both magnetic cores, and one or more of the turns of the primary winding set 404, e.g., the short winding 404b, may be wound only around the transformer core 402. In some implementations, all of the turns of the primary winding set 404 can be windings 404a that are wound around both magnetic cores.

[0048] In operation, the time-varying (alternating) current i p is applied to the primary winding set 404, which includes both the long winding 404a and the short winding 404b, a clockwise magnetic flux φ T is induced in the transformer core 402 according to the following relationship:

[0049]

number

[0050] Time-varying (AC) current i s is applied to the secondary winding set 406, a clockwise magnetic flux φ T is induced in the transformer core 402 according to the following relationship:

[0051]

number

[0052] The total magnetic flux induced in the transformer core 402 is given by the sum of two contributions:

[0053]

number

[0054] The current i applied to the primary winding set 404 p Also, clockwise magnetic flux φ is generated in the inductance core 400 according to the following relationship: I Induce.

[0055]

number

[0056] The current is does not contribute to the magnetic flux φI in the inductance core 400. However, energizing the secondary winding set 406 can indirectly affect the inductance core 400 by inducing a current in the primary winding set 404.

[0057] At 504, the method 500 includes inducing a current in the secondary winding set 406, according to some implementations of the present disclosure shown and described with reference to Figure 6. Because the secondary winding set 406 is wound around one of the magnetic cores, a magnetic flux generated by the current i p in either core coupled to the secondary winding set 406 induces a current therein.

[0058] At 506, the method 500 includes operating the high-power nested transformer 206, which operates the nested transformer to supply power to an EV charger, e.g., the EV charger 102, via the secondary winding set 406. The high-power nested transformer 206 operates in a DC-DC converter with less power loss than a conventional transformer and inductor combination constructed from separate components. In some implementations, the electrical behavior of the high-power nested transformer 206 may be substantially the same as a non-nested transformer with additional stray / resonant inductance. However, an advantage of the high-power nested transformer 206 is that the overall length of the copper windings is shorter than the length of the windings of an equivalent non-nested transformer. For example, the length of the copper windings in the high-power nested transformer 206 may be approximately 10 meters, compared to approximately 13 meters for a non-nested transformer. Fewer windings lower the resistive "I2R" power losses in the copper wire. As the current through the windings increases, the difference in power loss between a conventional transformer and the high-power nested transformer 206 increases. Therefore, in high-power applications, reducing the length of the copper windings is the preferred method for addressing the dominant loss source, i.e., losses in the windings, as opposed to power losses in the magnetic core.

[0059] 7 is a cross-sectional view of the high-power nested transformer 206 shown in FIG. 4 during a short-circuit simulation in accordance with some implementations of the present disclosure. FIG. 7 illustrates different magnetic field strengths B in Tesla induced within the inductance core 400 in response to short-circuit excitation. In the short-circuit simulation shown in FIG. 7, i p n p =i s n s where n pis the number of turns in the primary winding set 404, and n s is the number of turns in the secondary winding set 406, and i p is the current in the primary winding set 404, and i s is the current in the secondary winding set 406. A short-circuit magnetic flux is induced in the inner inductance core 400. The magnetic field strength generated in the inductance core 400 is greatest near the center of the inductance core 400 and decreases in strength with radial distance away from the central longitudinal axis Z-Z'. In some implementations, the maximum strength of the magnetic field induced during the short-circuit simulation may be about 0.3 Tesla to about 0.4 Tesla.

[0060] 8 is a cross-sectional view of the high-power nested transformer 206 shown in FIG. 4 during an open-circuit simulation in accordance with some implementations of the present disclosure. FIG. 8 illustrates different magnetic field strengths B in Tesla induced in the transformer core 402 in response to open-circuit excitation. In the simulation shown in FIG. 8, the current i in the secondary winding set 406 s = 0. The open circuit magnetic flux is the current i in the primary winding set 404. p The magnetic field strength within each of the stacked outer magnetic cores is greatest nearest the center of the transformer core 402 and decreases with increasing radial distance from the central longitudinal axis Z-Z'. In some implementations, the strength of the magnetic field induced within the outer transformer core 402 during an open-circuit simulation may be approximately 0.3 Tesla.

[0061] As described above, various implementations of the high-power nested transformer 206 can improve the efficiency of operating the EV charger 102. In some implementations, core losses are reduced by reducing the volume of the magnetic core through the use of a nested toroidal structure. In some implementations, resistive losses are reduced by reducing the length of copper wire required for the transformer windings.

[0062] In the foregoing description, when an element, such as a layer, region, or substrate, is referred to as being on, connected to, electrically connected to, coupled to, or electrically coupled to another element, it will be understood that it can be directly disposed on, connected to, or coupled to the other element, or that one or more intervening elements may be present. Conversely, when an element is referred to as being directly on, directly connected to, or directly coupled to another element or layer, no intervening elements or layers are present. Throughout the detailed description of the present invention, the terms directly, directly connected, or directly coupled may not be used, but elements shown as being directly on, directly connected, or directly coupled may be referred to as such. The claims of this application may be amended to describe the exemplary relationships described herein or shown in the figures.

[0063] As used herein, the singular can include the plural unless the context clearly dictates otherwise. Spatially relative terms (e.g., throughout, above, above, below, lower, underneath, lower, top, bottom, etc.) are intended to encompass different orientations of the device during use or operation in addition to the orientation depicted in the drawings. In some implementations, the relative terms above and below can include vertically above and vertically below, respectively. In some implementations, the term adjacent can include laterally adjacent or horizontally adjacent.

[0064] Some implementations may be implemented using various semiconductor processing and / or packaging technologies, such as, but not limited to, silicon (Si), silicon carbide (SiC), gallium arsenide (GaAs), gallium nitride (GaN), and / or other types of semiconductor processing technologies associated with semiconductor substrates.

[0065] While certain features of the described implementations have been illustrated as described herein, those skilled in the art will now recognize numerous modifications, substitutions, changes, and equivalents. For example, features illustrated with respect to one implementation may, where appropriate, be included in other implementations. It will therefore be understood that the appended claims are intended to cover all such modifications and changes as fall within the scope of the implementations. These have been presented by way of example only, and not limitation, and it will be understood that various changes in form and detail may be made. Any portions of the apparatus and / or methods described herein may be combined in any combination except mutually exclusive combinations. The implementations described herein may include various combinations and / or subcombinations of functions, components, and / or features of the different implementations described.

Claims

1. a base toroidal outer core having an opening and a longitudinal axis passing through the opening; a base toroidal inner core disposed within the opening and coaxial with the base toroidal outer core; a first set of conductive windings wound around the base toroidal outer core and the base toroidal inner core and passing through the opening; a second set of conductive windings wound around the base toroidal outer core and passing through the opening; and An apparatus comprising:

2. one or more additional toroidal outer cores stacked on the base toroidal outer core to form an outer cylinder having an opening, the first and second sets of conductive windings being wound around the outer cylinder and passing through the opening; or an additional toroidal inner core stacked on the base toroidal inner core to form an inner cylinder having an opening, the first set of conductive windings being wound around the inner cylinder and passing through the opening; The apparatus of claim 1 further comprising:

3. The outer cylinder is a transformer core and the inner cylinder is an inductor core; or the second set of conductive windings is shorter than the first set of conductive windings by a length equal to approximately twice the radial thickness of the base toroidal inner core; or the base toroidal outer core and the base toroidal inner core comprise a ferrite material; 3. The apparatus of claim 2.

4. energizing a primary winding of the nested transformer to induce a magnetic field in the outer transformer core and the inner inductor core; inducing a current in a secondary winding of a nested transformer via the magnetic field in the outer transformer core; operating the nested transformer to supply power to an electric vehicle charger through the secondary winding; Including, operating the nested transformer includes energizing a long primary winding wound around both the outer transformer core and the inner inductor core; or operating the nested transformer includes energizing a short primary winding wound around the outer transformer core; or During operation of the nested transformer, the power-to-volume ratio is greater than 10 kW / liter; method.

5. 1. An electric vehicle charging station comprising: a power module including a printed circuit board; a nested transformer coupled to the printed circuit board, the nested transformer having an inner core within an outer core; a microcontroller mounted on the printed circuit board and coupled to the nested transformer, the microcontroller configured to control operation of the nested transformer; a cable configured to couple the power module to an electric vehicle; additional nested transformers coupled in parallel to increase the charging capacity of the electric vehicle charging station; additional power modules coupled in parallel to increase the charging capacity of the electric vehicle charging station; Equipped with the power module comprises silicon carbide (SiC); or the nested transformer comprises a stack of multiple toroidal outer magnetic cores; or the nested transformer has a substantially circular footprint on the printed circuit board; or the electric vehicle charging station provides a total power of about 300 kW; or the power module provides approximately 25 kW of power; or the electric vehicle charging station is configured to operate at 240V; Electric vehicle charging station.

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