CN118020393A

CN118020393A - System and method for power conversion using LC filters with inductors embedded in the plates

Info

Publication number: CN118020393A
Application number: CN202280065123.6A
Authority: CN
Inventors: M·普雷德尔; 周力为; W-M·欧尔; M·詹恩斯
Original assignee: Columbia University in the City of New York
Current assignee: Columbia University in the City of New York
Priority date: 2021-07-27
Filing date: 2022-07-27
Publication date: 2024-05-10
Also published as: CN118020243A; CN117981207A; CN118020244A

Abstract

Embodiments are disclosed that include a non-isolated power converter system including a filter including an inductor and a capacitor. The inductor of the filter includes a core portion and a winding portion. The core may comprise differently shaped core structures. The winding portion includes windings embedded within the printed circuit board. The printed circuit board windings may include litz wire and have one or more controllers or power switching elements on the printed circuit board.

Description

System and method for power conversion using LC filters with inductors embedded in the plates

Cross-reference to related applications

The present application claims priority from U.S. provisional application No. 63/226,136, U.S. provisional application No. 63/242,840, U.S. provisional application No. 63/345,896, U.S. provisional application No. 63/351,768, U.S. provisional application No. 63/226,059, U.S. provisional application No. 63/270,311, and U.S. provisional application No. 63/319,122, each of which is incorporated herein by reference in its entirety, as filed on 7 months 27, 2021, U.S. provisional application No. 63/226,059, U.S. provisional application No. 63/270,311, and U.S. provisional application No. 63/319,122, as filed on 3 months 11, 2022.

Statement regarding federally sponsored research

The invention was completed with government support under 1653574 awarded by the national science foundation. The government has certain rights in this invention.

Background

Various types of power converters have been produced and used in many industries and environments. Example power converters include Alternating Current (AC) to Direct Current (DC) rectifiers, DC to AC inverters, and DC to DC converters. An AC-to-DC rectifier (also referred to as an AC/DC rectifier) converts AC power to DC power. DC-to-AC inverters, also known as DC/AC inverters, convert DC power to AC power. The power converter may be used for various purposes, such as rectifying AC power from an AC grid power source to DC power for charging a battery, or inverting DC power from a battery to AC power to drive a motor or supplying AC power to an AC grid. Further, the power converter may be used in various scenarios, such as in or connected to an electric vehicle, an engine generator, a solar panel, etc.

Disclosure of Invention

The power converter may be described in terms of power conversion efficiency, power density, and cost, among other characteristics. In general, it is desirable to have a power converter that is more power efficient, higher power density, and lower cost. An efficient power converter is capable of converting power (e.g., AC to DC, DC to AC, and/or DC to DC) without significant energy loss. Low efficiency power converters experience higher energy losses during power conversion. For example, such energy loss may be manifested as heat generated by the power converter when converting power. The power efficiency of a power converter, inductor, or other electronic component may be expressed as a percentage between 0 and 100% and based on the power input of the component and the power output from the component using the equation: power efficiency= (power output)/(power input). A power converter with a high power density has a high ratio of output by the power converter compared to the physical space occupied by the power converter. The power density may use the equation: power density= (power output)/(volume of power converter).

Energy costs, including monetary and environmental costs, remain an important factor in many industries employing power converters. Thus, even a slight increase (e.g., one tenth) in power efficiency of the power converter may be significant and highly desirable. Similarly, a reduction in the materials and dimensions of the power converter may be significant and highly desirable, allowing for a reduction in the cost and physical space of accommodating the power converter in a system incorporating the power converter.

In a power converter, an inductor that is part of the LC filter may account for a significant portion of the total power loss of the converter. For high power applications, high frequency power converters with soft switching capability, system efficiency may be highly correlated to the electromagnetic performance of the inductor. Additionally, the volume of the inductor of the LC filter can affect the power density of the power converter. The efficient design of the inductor for soft switching helps to achieve higher efficiency, higher power density and lower cost of the power converter. Some examples of LC filters and inductors of LC filters described herein provide one or more benefits, such as lower cost, improved voltage regulation, less power dissipation, improved ability to withstand heavy load currents, lower ripple factor, electromagnetic interference (EMI) reduction filters, filtering higher power signals, and reduced or eliminated ventilation because less heat is generated in the inductor.

In one embodiment, a non-isolated power converter system includes a power converter including a power switching element. The controller is configured to drive the power switching element to convert the received power and output the converted power. The controller is configured to drive the power switching element using a Variable Frequency Soft Switch (VFSS). A filter including an inductor and a capacitor is coupled to the first side of the power converter to filter the power signal on the first side of the power converter. The signal received by the filter has a current ripple of at least 200% peak-to-peak ripple relative to the local average current. The inductor of the filter includes a core portion and a winding portion. The winding portion includes windings embedded in a printed circuit board.

In one embodiment, an inductor for a filter in a non-isolated power converter system includes a core and a winding portion, and the winding portion forms an inductor with the core. The winding portion includes a winding embedded in the printed circuit board and having a first terminal and a second terminal. The windings are embedded in the printed circuit board forming a litz PCB, wherein the windings comprise multiple layers of parallel strands routed in the printed circuit board.

In one embodiment, an inductor for a filter in a non-isolated power converter system includes a winding portion including a winding embedded in a printed circuit board, and the winding forms a conductor loop including a first terminal and a second terminal. The core forms an inductor including a winding portion, and the core includes a first core and a second core on opposite sides of the winding portion. The first core and the second core include planar surfaces facing the conductor loop and substantially parallel to the printed circuit board.

In one embodiment, an inductor for a filter in a non-isolated power converter system includes a winding portion including a winding embedded in a printed circuit board, and the winding forms a conductor loop including a first terminal and a second terminal. The core forms an inductor together with the winding portion, and the core includes a first core opposite to the open air portion. The first core includes a base and three legs extending from the base, with a middle leg of the three legs extending through an opening defined by the conductor loop.

In one embodiment, a non-isolated power converter system includes a power converter including a power switching element and a controller configured to drive the power switching element to convert received power and output the converted power. The filter includes an inductor and a capacitor, and the filter is coupled to the first side of the power converter to filter the power signal on the first side of the power converter. The inductor further includes a core portion and a winding portion. The printed circuit board includes an embedded winding portion and a printed circuit board located in one or more controllers or one or more power switching elements.

The foregoing and other aspects and advantages of the present disclosure will become apparent from the following description. In this description, reference is made to the accompanying drawings which form a part hereof, and in which is shown by way of illustration one or more embodiments. However, these examples do not necessarily represent the full scope of the invention and, therefore, reference should be made to the claims and herein for interpreting the scope of the invention. Like reference numerals will be used to refer to like parts between the drawings in the following description.

Drawings

Fig. 1 illustrates a power converter system according to some embodiments.

Fig. 2 illustrates a modified half-bridge converter circuit in accordance with some embodiments.

Fig. 3 illustrates a three-phase DC/AC application with LC filters, according to some embodiments.

Fig. 4 illustrates timing diagrams and boundary conditions for a soft switch, according to some embodiments.

Fig. 5 illustrates a control diagram for controlling a pair of switching elements of a power converter, in accordance with some embodiments.

Fig. 6 illustrates another control diagram for controlling a pair of switching elements of a power converter, in accordance with some embodiments.

Fig. 7A illustrates an isometric view of an EE core inductor comprising copper wire windings.

Fig. 7B illustrates a perspective view of an EE core inductor including windings embedded in a printed circuit board.

Fig. 8A illustrates an isometric view of an EI core inductor including windings embedded in a printed circuit board.

Fig. 8B illustrates a perspective view of an EI core inductor including windings embedded in a printed circuit board.

Fig. 9A illustrates an isometric view of an EA core inductor including windings embedded in a printed circuit board.

Fig. 9B illustrates a perspective view of an EA core inductor including windings embedded in a printed circuit board.

Fig. 10A illustrates an isometric view of a II core inductor including windings embedded in a printed circuit board.

Fig. 10B illustrates a perspective view of a II-core inductor including windings embedded in a printed circuit board.

Fig. 11A illustrates an isometric view of a II core.

Fig. 11B illustrates an isometric view of an EA core.

Fig. 12 includes a plan view of a printed circuit board.

Fig. 13A illustrates a plan view, perspective view of a solid winding embedded printed circuit board.

Fig. 13B illustrates a plan view, perspective view of the litz winding embedded printed circuit board.

Fig. 14 illustrates an isometric view of the litz winding.

Fig. 15 illustrates an enlarged portion of the litz winding of fig. 14.

Fig. 16 illustrates an isometric view of a litz winding comprising multiple layers.

Fig. 17 shows a graph of resistance factor versus frequency according to the type of PCB windings and the number of PCB windings.

Fig. 18 illustrates a comparison graph of inductor loss versus volume according to the type of core, the type of winding, and the number of windings.

Fig. 19 illustrates a comparative graph of inductor loss versus cost according to the type of core, the type of winding, and the number of windings.

Fig. 20 illustrates the embedded winding portion of the inductor and after one or more controllers or one or more power switching elements have been positioned in a single printed circuit board.

Fig. 21 illustrates a process of power conversion according to some embodiments.

Detailed Description

One or more embodiments are described and illustrated in the following specification and drawings. The embodiments are not limited to the specific details provided herein and may be modified in various ways. Furthermore, other embodiments not described herein are possible. In addition, functions performed by multiple components may be integrated and performed by a single component. Also, the functions described herein as being performed by one component may be performed by multiple components in a distributed fashion. Additionally, components described as performing a particular function may also perform other functions not described herein. For example, a device or structure that is "configured" in some manner is configured in at least that manner, but may also be configured in ways that are not listed.

As used in this disclosure, "non-transitory computer-readable medium" includes all computer-readable media, but does not include transitory propagating signals. Thus, the non-transitory computer readable medium may include, for example, a hard disk, a CD-ROM, an optical storage device, a magnetic storage device, a ROM (read only memory), a RAM (random access memory), a register memory, a processor cache, or any combination thereof.

Also, the phraseology and terminology used herein is for the purpose of description and should not be regarded as limiting. For example, the use of "including," "comprising," or "having" and variations thereof herein is meant to encompass the items listed thereafter and equivalents thereof as well as additional items. Additionally, the terms "connected" and "coupled" are used broadly and encompass both direct and indirect connections and couplings, and may refer to physical or electrical connections or couplings. Furthermore, the phrase "and/or" as used with two or more items is intended to encompass both the individual items as well as the two items. For example, "a and/or b" is intended to cover: a (but not b); b (but not a); and a and b.

Systems and methods related to power converters are disclosed herein that may provide power conversion with increased power efficiency, increased power density, and/or reduced cost, among other advantages.

I. Power converter system

Fig. 1 illustrates a power converter system 100 according to some embodiments. The power converter system 100 includes an electronic controller 105, a first load/source 110, a power converter 115, an LC filter 120, a contactor 125, a second source/load 130, a third source/load 135, and one or more sensors 140.

In operation, the electronic controller 105 controls the power switching elements of the power converter 115 with high frequency control signals to convert power (i) from the first source/source 110 acting as a source to the second source/load 130 or the third source/load 135 acting as a load (depending on the state of the contactor 125), or (ii) from the second source/load 130 or the third source/load 135 acting as a source (depending on the state of the contactor 125) to the first source/source 110 acting as a load. Thus, when the first source/load 110 is used as a source for the power converter 115, the second source/load 130 (or the third source/load 135, depending on the state of the contactor 125) is used as a load for the power converter 115. Conversely, when the first load/source 110 is used as a load for the power converter 115, the second source/load 130 (or the third source/load 135, depending on the state of the contactor 125) is used as a source for the power converter 115.

The first load/source 110 may be a direct power (DC) load, a DC source, or both a DC load and a DC source (i.e., depending on the mode of the power converter 115, it may be used as a DC source in some cases, and as a DC load in other cases). In some examples, the first load/source 110 is a battery. The second source/load 130 and the third source/load 135 may be a DC load, a DC source, both a DC load and a DC source, an AC load, an AC source, or both an AC load and an AC source (i.e., depending on the mode of the power converter 115, in some cases acting as an AC source, and in other cases acting as an AC load). In some examples, the second source/load 130 is an electric motor and the third source/load 135 is an AC generator or an AC power supply grid. In some examples, the second source/load 130 and the third source/load 135 are both DC batteries. In some examples of the system 100, the second source/load 130 is connected to the LC filter 120 without the intermediate contactor 125, and the contactor 125 and the third source/load 135 are not present in the system 100.

The first load/source 110 is coupled to the power converter 115 at a first side of the power converter 115, and the second source/load 130 (or third source/load 135, depending on the state of the contactor 125) is coupled to the power converter 115 at a second side of the power converter 115. Depending on the mode of the power converter, the first side may also be referred to as the input side or output side of the power converter 115, or as the DC side of the power converter 115. Depending on the mode of the power converter, the second side may also be referred to as the input side or output side of the power converter, as the DC side or AC side of the power converter 115, or as the interface side, depending on the power type of the second and/or third source/load 130, 135. In some embodiments, the second side of the power converter 115 may be an AC side having single phase AC power, three phase AC power, or an amount of AC power having another phase.

In some embodiments, the power converter 115 operates at a high DC voltage level. For example, in operation, the DC side of the power converter 115 has a DC voltage of at least 200V, at least 600V, at least 800V, at least 1000V, at least 1200V, between 200V and 1200V, between 600V and 1200V, between 800V and 1200V, or another range (e.g., across the input terminals of the power converter 115). Such high DC voltage levels may be desirable in some situations, such as some electric vehicles. For example, some current electric vehicles (e.g., passenger vehicles and hybrid electric vehicles) operate at a DC bus voltage of between about 200V and 400V. The DC bus voltage for passenger vehicles may increase in the future. In addition, some current electric vehicles (e.g., class 4-8, off-road, or other larger electric vehicles) may operate at DC bus voltages in excess of 1000V. However, high DC voltage levels may present challenges to typical power converter systems, such as increased leakage current, increased common mode voltage, higher rates of change of common mode voltage, and the like. When the second or third source/load is an electric motor (e.g., a traction motor in an electric vehicle), these challenges can lead to shaft voltage and bearing current (e.g., discharge events when lubricant dielectric breakdown occurs), resulting in bearing failure. However, as described herein, embodiments described herein may alleviate such challenges by, for example, variable frequency soft switches, elaborate LC filters, and/or additional capacitors. For example, in an electric vehicle environment, embodiments described herein may reduce bearing current and shaft voltage by controlling the common mode voltage of the system to remain below a threshold and/or by maintaining the variation of the common mode voltage below a rate of change threshold.

Sensor(s) 140 include, for example, one or more current sensors and/or one or more voltage sensors. For example, sensor(s) 140 may include respective current sensors and/or voltage sensors to monitor the current and/or voltage of each phase of one or more of first load/source 110, second source/load 130, third source/load 135, LC filter 120, or power converter 115. For example, when LC filter 120 is a three-phase LC filter, sensors 140 may include at least three current sensors, one for each sensing current at each phase of three-phase LC filter 120. In some embodiments, additional or fewer sensors 140 are included in the system 100. For example, the sensor 140 may also include one or more vibration sensors, temperature sensors, and the like. In some examples, rather than directly sensing a characteristic (e.g., current or voltage) at one or more nodes of the power converter 114, the controller 105 infers or estimates the characteristic.

Input-output (I/O) interface 142 includes or is configured to receive input from one or more inputs (e.g., one or more buttons, switches, touch screen, keyboard, etc.), and/or includes or is configured to provide output to one or more outputs (e.g., LEDs, display screen, speaker, tactile generator, etc.). Other electronic devices and/or users may communicate with the system 100, and in particular with the controller 105, via the I/O interface 142.

The electronic controller 105 includes an electronic processor 145 and a memory 150. Memory 150 includes one or more of Read Only Memory (ROM), random Access Memory (RAM), or other non-transitory computer-readable media. The electronic processor 145 is configured to, among other things, receive instructions and data from the memory 150 and execute the instructions, for example, to perform the functions of the controller 105 described herein, including the processes described below. For example, the memory 150 includes control software. As described in further detail below, in general, the electronic processor 145 may be configured to execute control software to monitor the system 100, the system 100 including the power converter 115 (e.g., based on sensor data from the sensor(s) 140), receive commands (e.g., via the input/output interface 142), and drive the power converter 115 (e.g., in accordance with the sensor data and/or commands). In some embodiments, instead of or in addition to executing software from memory 150 to perform the functions of controller 105 described herein, electronic processor 145 includes one or more hardware circuit elements configured to perform some or all of the functions described herein.

Although controller 105, electronic processor 145, and memory 150 are each illustrated as a respective single unit, in some embodiments, one or more of these components are distributed components. For example, in some embodiments, electronic processor 145 includes one or more microprocessors and/or hardware circuit elements. For example, the controller 105 or the electronic processor 145 may include a processor and a gate driver circuit, wherein the processor provides a PWM duty cycle and/or frequency to the gate driver circuit, and the gate driver circuit drives the power switching element according to the PWM duty cycle and/or frequency.

Upper capacitor for half-bridge switching converter topology

Fig. 2 illustrates an example of a half-bridge converter 200 that may be used as the power converter 115 of the system 100 of fig. 1. As shown, the converter 200 includes a DC terminal 220 (also referred to as a DC node, DC link, DC rail, etc.) having a positive DC terminal 222 and a negative DC terminal 224. The converter 200 further includes an interface terminal 225 (also referred to as an interface node) having a positive interface terminal 227 and a negative interface terminal 229. The converter 200 may operate as a bi-directional converter or as a unidirectional converter (in either direction), depending on the configuration and control of the system in which it is implemented. Thus, in some examples, DC terminal 220 may be an input terminal and interface terminal 225 may be an output terminal (e.g., DC/DC conversion and DC/AC inversion), and in some examples (e.g., AC/DC rectification), DC terminal 220 may be an output terminal and interface terminal 225 may be an input terminal. Additionally, the interface terminal 225 may be an AC input terminal (e.g., for AC/DC rectification), may be an AC output terminal (e.g., for a DC/AC inverter), or may be a DC output terminal (e.g., for DC/DC conversion).

The converter 200 further includes a DC link capacitor (C _DC) 230, a high-side (upper) power switching element (M1) 235 (also referred to as an upper switch 235), a low-side (lower) power switching element (M2) 240 (also referred to as a lower switch 240), a midpoint node 242 connecting the drain terminal of the upper switch 235 and the source terminal of the lower switch 240, and an LC filter 245.LC filter 245 is an example of LC filter 120 of system 100 of fig. 1.

The power switching elements 235 and 240 may be Field Effect Transistors (FETs), each having respective gate, source and drain terminals. The FET may be, for example, a MOSFET, a silicon carbide (SiC) FET, a gallium nitride (GaN) FET, and other types of FETs.

LC filter 245 includes switch-side inductor LF 250, lower capacitor C _B 255, and upper capacitor C _A. A switch-side inductor LF 250 is coupled between the midpoint node 242 and the filter node 260. For example, a first end of the switch-side inductor LF 250 is coupled to the midpoint node 242 and a second end is coupled to the filter node 260. A lower capacitor C _B 255 is coupled between the midpoint node 242 and the negative DC terminal 224. For example, a first end of the lower capacitor C _B is coupled to the midpoint node 242 and a second end is coupled to the negative DC terminal 224. Lower capacitor C _A is coupled between midpoint node 242 and positive DC terminal 222. For example, a first end of the lower capacitor C _A is coupled to the midpoint node 242 and a second end is coupled to the positive DC terminal 222.

In some examples, LC filter 245 is an LCL filter (LC filter with an additional inductor (L)) with an additional (interface) inductor coupled between filter node 260 and positive interface terminal 227.

The converter further includes drain-source capacitors C _DS a and 265b, and each is coupled across one of the switches 235, 240, respectively. Specifically, a first drain-source capacitor 265a is provided across the source terminal 270a and the drain terminal 275a of the upper switch (M1) 235, and a second drain-source capacitor 265b is provided across the source terminal 270b and the drain terminal 275b of the lower switch (M2) 240. The drain-source capacitors (C _DS) 265a-b may be collectively referred to herein as drain-source capacitor(s) (C _DS) 265.

The upper capacitor 215 allows the ripple current at the input and output nodes (nodes 222, 227) of the converter 200 to be shared. Since the ripple current on the input node and the ripple current on the output node have a certain correlation, the differential mode current of these input and output nodes can be eliminated by the capacitance. Such a reduction in differential mode current may result in improved EMI performance and reduced total capacitor ripple current compared to typical half-bridge converters (e.g., when the total capacitance between the two converters remains constant). Further, the reduction in the total capacitor ripple current may allow for a reduction in the capacitor size, for example, when the capacitor ripple current drives the capacitor size.

Drain-to-source capacitor (C _DS) 265 may slow down the voltage rise during the on-to-off transition of switches 235 and 240. This slowed voltage rise in turn may reduce switching losses of switches 235 and 240.

In some examples of converter 200, one or both of upper capacitor C _A and drain-source capacitor C _DS are not included in converter 200.

As described above, in some examples, the power converter 200 may be used as the power converter 115 of the system 100 in fig. 1. In the case where the power converter 115 (and thus the power converter 200) implements an AC/DC rectifier or a DC/AC inverter, the power converter 200 is a single-phase power converter 200. In some examples, multiple instances of power converter 200 are connected in parallel to collectively function as power converter 115 of fig. 1 and provide single-phase conversion (whether rectifying or inverting) or provide DC/DC power conversion. In some examples, power converter 115 is a multi-phase power converter (e.g., operating with three or more phases of AC power). In such examples, the power converter 115 may include multiple instances of the power converter 200, each instance associated with a phase of AC power, each instance having a shared DC terminal 220, and each instance having an independent V _Interface node 225. An example of such a power converter is provided in fig. 3. In some of these examples, multiple instances of power converters 200 are connected in parallel to collectively provide power conversion of the respective phases (e.g., two parallel power converters 200 for phase 1, two parallel power converters 200 for phase 2, and two parallel power converters 200 for phase 2). In some examples, a particular number of parallel power converters 200 and a number of phase changes provide single phase conversion (whether rectification or inversion) or provide DC/DC power conversion.

Fig. 3 illustrates a multiphase power converter system 300. The multiphase converter system 300 includes a multiphase converter 304, which multiphase converter 306 is coupled to a battery 306 on the DC side and to the AC power grid 302 via an LCL filter 308. The multiphase converter 304 may be used as the power converter 115 of the system 100 of fig. 1, and the LCL filter 308 may be used as the LC filter 120 of the system 100 of fig. 1. In operation, the multiphase converter 300 may be used as a DC/AC inverter or an AC/DC rectifier, depending on the source and the switches of the power switching elements.

The multi-phase converter 304 includes three instances of the power converter 200 of fig. 2, one for each phase of the AC power grid 302. Each example includes an upper switch 235 and a lower switch 240, with a drain-source capacitance coupled across each of these switches. The multiphase converter 300 is further coupled to a battery 310 via the DC terminal 220 and to an AC power grid 302 via the interface terminal 225. The multiphase converter 300 includes three LCL filters 308. Each LCL filter 308 includes components similar to LC filter 245 of fig. 2 with the addition of an interface inductor (L _fg) 347 coupled between filter node 260 and AC grid 302. That is, each LCL filter 308 includes a switch-side inductor 250 (also labeled L _fs,a、L_fs,b or L _fs,c), a lower capacitor 255 (also labeled C _f,a、C_f,b and C _f,c), an upper capacitor 215 (also labeled C _f,a、C_f,b or C _f,c). A switch-side inductor 250 is coupled between midpoint node 242 and filter node 260.

In the illustrated example, the multiphase converter 300 is coupled to a battery 306 and an AC power grid 302. In other examples, the multiphase converter 300 is coupled to a DC source/load (e.g., capacitor, supercapacitor, DC source from rectified AC power, etc.) other than the battery 306 and/or an AC source/load (e.g., three-phase motor, engine generator, etc.) other than the grid 302. Additionally, although multiphase converter 300 includes drain-source capacitors for each switch and interface inductors 347 for each phase, in some examples, one or more of these components are not included. Additionally, in some embodiments, an upper capacitor 215 for each phase is coupled between each filter node 260 and the positive DC node 222, such as shown in fig. 2 (for a single phase).

III variable frequency critical soft switch

In some examples, the half-bridge power converter 200 and/or the multi-phase power converter 300 are driven using a Variable Frequency Critical Soft Switching (VFCSS) scheme. The VFCSS approach may provide improved efficiency and reduced filter volume (i.e., improved power density) for the power converter. Soft switching allows the on-switching loss to be replaced with the off-switching loss, which is beneficial because the on-loss of silicon carbide (SiC) devices is typically much greater than the off-loss. This VFCSS technique enables an increase in switching frequency (e.g., 5 times) and a decrease in inductance (e.g., 20 times) while reducing FET losses, which results in improved power density and efficiency.

VFCSS is implemented by varying the switching frequency to achieve the desired inductor ripple current in the LC filter (e.g., in the switching side inductor 250 of the LC filter 245). The desired inductor ripple current may be derived such that the valley point of the inductor current reaches a predetermined value of the inductor threshold current I _L,thr. I _L,thr is set according to the dead time of the inductor 250 and the boundary conditions of peak/Gu Diangan device current, which can be derived from the output capacitance of the switching elements 235, 240. Fig. 4 shows the boundary relationship of dead time (T _d) with peak and Gu Diangan device currents I _L,max and I _L,min, respectively. The inductor current and dead time values that result in soft switching are identified as soft-open switching areas or regions and the inductor current and dead time values that do not result in soft switching are identified as hard switching areas or regions. The soft switching region represents an operation area where there is enough time and current to discharge the output capacitance of the power switching element (M1 or M2) before the power switching element (M1 or M2) is turned on. Analytically, these boundaries are represented as

1/2I_L,maxT_d≤Q_min≤0，

1/2I_L,minT_d≥Q_max≥0，

Where Q _min and Q _max are the minimum discharge thresholds of the switched output capacitances for the soft switches.

For high positive values of the DC inductor current, a large current ripple is required to maintain the Gu Diangan device current point below the threshold current level-I _L,thr. During the off transient of the lower switch, the negative inductor current will discharge the upper switch output capacitance. Similarly, for high negative values of the DC inductor current, a large current ripple is also required to ensure that the peak inductor current point is greater than the threshold current I _L,thr. If the lower switch output capacitance is fully discharged by the positive inductor current during the off transient of the upper switch, then Zero Voltage Switching (ZVS) of the lower switch will be achieved. In general, to achieve fully soft switching throughout a cycle (e.g., throughout a grid cycle), the current ripple should be large enough to ensure a bi-directional inductor current path, or require an extended dead time. Since unnecessarily large dead times can cause distortion, VFCSS adjust the switching frequency to maintain a critical soft switching throughout the period. The VFCSS scheme is implemented to maintain a positive threshold current during the negative portion of the cycle and a negative threshold current during the positive portion of the cycle. For any threshold, the switching frequency to achieve this can be calculated with the following equation:

Where I _L,thr is the boundary threshold current for the soft switch, which can be derived from fig. 4 by a given dead time (T _d), and I _L is the inductor current, and where d is the reference duty cycle (a value between 0 and 1).

Fig. 5 illustrates a control diagram of a pair of switching elements for controlling a power converter. Specifically, the control diagram illustrates an example of the controller 105 implementing an example control scheme for VFCSS control of the power converter 200 including the upper capacitor 215. The controller 105 includes a duty cycle generation controller 405 and a frequency generation controller 410, which may be regulators for generating a reference duty cycle (d x) and a reference switching frequency (F _SW x), respectively. The duty cycle generation controller 405 may generate a reference duty cycle (d) based on sensed (or estimated) characteristics of the power converter 200, such as current and/or voltage. For example, the duty cycle generation controller 405 may implement a PID controller or another type of regulator. The frequency generation controller 410 may generate a reference switching frequency (F _SW) based on the sensed (or estimated) characteristics of the power converter 200 and the equation for calculating F _SW as described above. The gate driver 415 receives a reference duty cycle (d) and a reference switching frequency (F _SW) from the controllers 405 and 410, respectively. Based on these received reference values, the gate driver 415 generates a first PWM control signal for the upper switch (M1) 235 and generates a second PWM control signal for the lower switch (M2) 240. For example, the gate driver 415 generates a first PWM control signal having a Frequency (FSW) equal to the reference switching frequency and a duty cycle (d ₁) equal to the reference duty cycle (d). Similarly, the gate driver 415 generates a second PWM control signal having a frequency f _SW equal to the reference switching frequency (f _SW x) and a duty cycle d ₂ equal to 1-d1- (T _d/f_sw), and wherein the on edge of the second PWM control signal lags the off edge time T _d/2 of the first PWM control signal and the off edge of the second PWM control signal leads the on edge time T _d/2 of the PWM signal.

Fig. 6 illustrates another control diagram for controlling a pair of switching elements of a power converter. Specifically, the control diagram illustrates a more detailed example of the controller 105 implementing VFCSS control as provided with respect to fig. 5. Fig. 6 is merely one example of an implementation of controller 105 implementation VFCSS, and in other embodiments controller 105 implements VFCSS using other methods. For example, a different regulator than that shown in fig. 6 may be used to generate the reference duty cycle and the reference switching frequency.

In the example of fig. 6, the duty cycle generation controller 405 includes a two-phase regulator having a first voltage regulation phase that compares a reference output voltage to a sensed output voltage of the converter (e.g., vo at interface terminal 225) and generates a reference inductor current (I _L x). The second current regulation stage receives the reference inductor current (I _L x) and compares the reference inductor current (I _L x) to the sensed inductor current (I _L) of the inductor 250 and generates a reference duty cycle d.

Also in the example of fig. 6, the frequency generation controller 410 uses the equation provided above to determine the reference switching frequency (f _SW). In some examples, the frequency generation controller 410 dynamically calculates an equation to generate the reference switching frequency (f _SW), and in other examples, a lookup table is provided to map the input of the frequency generation controller 410 to a particular value of the reference switching frequency (f _SW). In the frequency generation controller 410, a frequency limiter stage is also provided, which limits the reference switching frequency (fsw) to a maximum value and a minimum value.

As shown in fig. 6, the gate driver 415 receives a reference duty cycle (d x) and a reference switching frequency (f _SW). As previously described, the gate driver 415 then generates PWM control signals to drive the power switching elements of the power converter 200.

In a power converter, the inductor accounts for a significant portion of the total power loss. For high power applications, high frequency power converters with soft switching capability, system efficiency may be highly correlated to the electromagnetic performance of the inductor. Additionally and alternatively, the volume of the inductor may affect the power density of the energy conversion system. The efficient design of the inductor for soft switching helps to achieve higher efficiency, higher power density and lower cost of the power converter. By combining inductor and capacitor components having opposite properties, noise can be reduced and specific signals can be identified. Some examples of LC filters described herein provide one or more benefits, such as lower cost, improved voltage regulation, less power dissipation, improved ability to withstand heavy load currents, lower ripple factors, filtering higher power signals, and reduced or eliminated ventilation because less heat is generated in the inductor.

LC filter inductor

Conventional inductors include a coil wound around a core. When current begins to flow into the coil, the coil begins to establish a magnetic field. The electromagnetic storage capacity of a conventional inductor is controlled by the number of coils wound around the core, the ferrous material, the diameter of the coils, and the magnetic wire length of the coils.

Core of LC filter inductor

Referring to fig. 7A and 7B, an "EE" shaped core 700 is illustrated as part of an inductor 701 and an inductor 702, respectively. Specifically, referring to fig. 7A, an inductor 701 includes a core 705 that receives a winding portion 710. The cores of the various inductors provided herein may take a variety of shapes. The core 705 of fig. 7A includes an "EE" shaped core 700. The winding portion 710 includes a wire inductor 715, which may be litz wire or solid (cross-sectional) copper wire, wound on an "EE" shaped core 700. The "EE" shaped core 700 includes a first portion 720 and a second portion 725, each shaped like an "E", having a base 730, the base 730 having three legs 735 extending away from the base 730. The legs 735 and the base 730 may each have a generally rectangular cuboid shape. Distal ends 740 of respective legs 735 of the first and second sections 720, 725 are positioned opposite each other, separated by an air gap 745, and bases 730 of the two sections 720, 725 are on opposite ends of the "EE" shaped core 700. The middle leg 750 and the outermost leg 755 are parallel to each other, and the thickness of the middle leg 750 may be different from the thickness of the outermost leg 755.

The "EE" core, like the other cores provided herein, may also be combined with a winding section comprising or formed by PCB windings. Referring specifically to fig. 7B, an inductor 702 having an "EE" shaped core 700 (as the core) and PCB windings 760 (as the winding portions) is illustrated. Conductive strips 765 are used to connect PCB windings 760. The PCB windings 760 include embedded wiring, which will be discussed in more detail below and through fig. 11 and 12.

Referring to fig. 8A and 8B, an "EI" shaped core 800 is illustrated as part of an inductor 801 and an inductor 802, respectively. The "EI" shaped core 800 includes a first portion 805 and a second portion 810. Referring specifically to fig. 8A, an inductor 801 having an "EI" shaped core 800 (as the core) and litz PCB windings 815 (as the winding portions) is illustrated. Litz PCB winding 815 is discussed in more detail below and with reference to fig. 14-15. The first portion 805 of the core 800 is shaped like an "E" that includes a base 820, the base 820 having three legs 825 extending away from the base 820. The second portion 810 is shaped like an "I" that includes a rectangular cuboid shape that is similar to the shape of the base 820 of the first portion 805 without the legs 825. The base 820 includes or defines a first surface 830 and a second surface 835. Distal ends 840 of legs 825 of first portion 805 protrude away from base 820 of first portion 805 toward one of the surfaces of second portion 810 (e.g., toward surface 830). The first section 805 and the second section 810 are separated by an air gap 745. Additionally, the bases 820 of the second portion 810 and the first portion 805 are parallel and located at opposite ends of the inductor.

Referring specifically to fig. 8B, an inductor 802 is illustrated having an "EI" shaped core 802 (as the core) and PCB windings 850 (as the winding portions). A conductive strap 855 may be used to connect PCB windings 850. The PCB winding 850 includes embedded wiring, which will be discussed in more detail below and through fig. 11 and 12.

Referring to fig. 9A and 9B, an "EA" shaped core 900 is illustrated as part of an inductor 901 and an inductor 902, respectively. Referring specifically to fig. 9A, an inductor 901 is illustrated having an "EA" shaped core 900 (as the core) and litz PCB windings 905 (as the winding sections). The "EA" shaped core 900 includes a first portion 910 shaped like an "E" having a base 915, the base 915 having three legs 920 extending away from the base 915. The "EA" shaped core 900 further includes an air portion 925 that represents "a" of the "EA" shaped core 900 and is open on the side 930 of the inductor 901. Since the three legs 920 extend from the base 915 of the "EA" shaped core 900, the air portion 925 is adjacent to the distal ends 935 of the three legs 920 extending from the base 915 and opposite the base 915 of the "E" shaped core. A window 940 is formed between the three legs 920. The window receives the PCB windings 905 and, with the height of the legs 920, the height of the stacked PCB windings may be defined or limited.

Referring specifically to fig. 9B, an inductor 902 having an "EA" shaped core 902 (as the core) and a PCB printed inductor 945 (as the PCB portion) is illustrated. An air gap 745 may exist between each pair of extension legs 920 of the "EA" shaped core 900. The height of the air gap 745 of the "EA"900 shaped core may be adjusted by varying the leg height LH of the leg 920 (or the extension length from the base 915) or by inserting additional layers of PCB printed inductor 945 windings. For example, in comparison to inductor 902, inductor 901 of fig. 9A has a minimal air gap because the height of PCB winding 905 is nearly the same as the height of leg 920. The air gap height of the two inductors is in some examples larger and in other examples shorter (e.g., based on the height of the legs 920 and the number of PCB layers 905, 945).

Referring to fig. 10A and 10B, an "II" shaped core 1000 is illustrated as part of an inductor 1001 and an inductor 1002, respectively. Referring specifically to fig. 10A, an inductor 1001 having a "II" shaped core 1000 (as the core) and litz PCB windings 1005 (as the winding sections) is illustrated. The "II" shaped core 1000 includes a first portion 1010 and a second portion 1015, each shaped like an "I" having a generally rectangular cuboid shape. The first 1010 and second 1015 portions of the "II" shaped core are separated from each other by an air gap 745. The litz PCB winding 1005 is sandwiched between the first "I" section 1010 and the second "I" section 1015. In this inductor 1001, the core does not include legs inserted into or through the winding portion, and the winding portion is not wound around a portion of the core 1000.

Referring specifically to fig. 10B, inductor 1002 includes a "II" shaped core 1000 (as a core), and PCB windings 1025 (as winding portions) are sandwiched between first portion 1010 and second portion 1015 of "II" shaped core 1000 in air gap 745. Like the inductor 1001, in this inductor 1002, the core does not include legs inserted into or passing through the winding portion, and the winding portion is not wound around a portion of the core 1000.

Different core shapes and compositions provide different advantages and trade-offs. For example, referring to fig. 7A and 7B, an "EE" shaped core 700 has a greater volume and more material than other core shapes (e.g., "EA", "EI", and "II") increasing the cost and overall size of inductors 701 and 702 comprising the core. However, the "EE" shaped core 700 may allow for windings with greater heights (or windows), which allows more windings to be stacked in parallel to reduce coil resistance and copper losses.

Referring to the "II" shaped core 1000 of fig. 11A, the "II" shaped core 1000 has a smaller volume than other core shapes (e.g., "EA", "EI", and "EE") resulting in reduced material costs and inductor size. However, the "II" shaped core includes a minimum air gap 745, limiting the number of turns of the winding portion (whether wound wire or stacked PCB). Accordingly, the number of turns of windings and air gap 745 may be carefully designed to support the inductance desired to reduce copper losses. Still referring to fig. 11A, the air gap 745 between the first "I" shape 1110 and the second "I" shape 1115 may be determined by the height H of the windings, which may be determined by the number of PCB windings.

Referring to the "EI" shaped core 800 (of fig. 8A and 8B), the "EI" shaped core 800 is a mixture of the "EE" shaped core 700 and the "II" shaped core 1000, which can be used to reduce the volume cost (of the "EE" shape) and the copper loss (of the "II" shape). The "EI" shaped core 800 enables stacking of PCB printed windings while providing the benefit of being able to increase the air gap 745 more than (and including more windings than) the "II" shape.

Referring to the "EA" shaped core 900 of fig. 11B, the "EA" shaped core 900 includes an air gap 745, the air gap 745 being bounded by an open area 1150 on top of the "E" shaped core (e.g., an area defined by a plane extending through the distal ends 1160 of the legs 1162). Thus, in other words, the air gap 745 is limited by the length of the leg 1162 (or the extension of the leg 1162 from the base 1165). The "E" shaped core 900 defines a magnetic flux path that, at least in some examples, passes through only two window widths (W) at the top of the "E" shaped core 900 to complete a magnetic flux loop. Thus, in at least some examples, the number of PCB printed windings may not exceed a height H between the distal ends 1160 of the three legs 1162 and the base 1165. In some examples, the air gap 745 of the "EA" shaped core 900 is approximately the same as the width W of the window 940, and the "EA" shaped core 900 uses less magnetic (core) material than the "EE" shape (50% less) and than the "EI" shape, thereby reducing the cost and volume of the inductor.

Although the inductors of fig. 7B-10B are illustrated as having a particular size and number of PCB windings, the particular size and number of PCB windings varies in some examples. For example, in some examples, more or fewer PCB windings may be provided in the inductors of fig. 7B-10B. Additionally, in some examples, the specific length of the legs or spacing between the legs of the "E" shaped base, or the specific length, width, and height of the "I" shaped base of the core may be increased or decreased.

Winding of LC filter inductor

The inductor design of the present disclosure includes a winding portion surrounding one of the above-mentioned cores. Unlike conventional inductors that include wire wound coils, the present disclosure includes a Printed Circuit Board (PCB) winding, such as PCB winding 1200 of fig. 12, that includes a circuit board or substrate 1205 with an embedded inductor winding (not shown in fig. 12). The circuit board 1205 of the PCB winding 1200 includes or defines a hole 1210 disposed about the center of the PCB winding 1215. For example, in fig. 12, the aperture 1210 is rectangular in shape, but may include a different shape, such as circular, oval, or triangular, or may not be present in some examples. Similarly, the peripheral shape of the circuit board 1205 may be different from the rectangular shape shown in fig. 12, and may alternatively be a circle, an ellipse, a triangle, or the like. Inductors including PCB windings 1200 with embedded windings provide various advantages over traditional conductively wound inductors, such as, but not limited to, low cost, more robust windings, and reduced complexity for mass production.

Fig. 13A and 13B illustrate PCB windings 1300 and 1302, respectively, which may be examples of PCB winding 1200. The embedded windings of PCB windings 1300 and 1302 include a conductive material such as copper, ferrite material, or another material with similar properties (e.g., low power loss density). The embedded windings may have structures such as rectangular foil solid conductors, round wire solid conductors, and round litz wire conductors.

The PCB winding 1300 of fig. 13A may be referred to as a solid PCB winding 1300, which includes a circuit board 1310 having solid circular wire conductors 1315 embedded therein. The solid circular wire conductors 1315 extend in a rectangular spiral 1320 within the circuit board 1310 around the holes 1325 of the circuit board 1310. The number of loops that solid circular wire conductors 1315 pass over circuit board 1310 may vary based on design considerations of the inductor. For example, in general, the more loops, the greater the inductance provided by the inductor. Within circuit board 1310, embedded solid wire conductors 1315 may form multiple loops through one or both of: (1) Multiple vertical layers of circuit board 1310 such that the loops are stacked above/below each other, and (2) loops with different diameters are formed within a single layer (e.g., in the case of 2 loops, as shown in fig. 13A, the wires form inner and outer loops on a single layer).

The PCB winding 1302 of fig. 13B may be referred to as a litz PCB winding 1302. Litz PCB winding 1302 includes a circuit board 1350 having litz conductors 1355 embedded therein. As explained further below, litz conductor 1355 has properties similar to a litz wire, which is a wire having a plurality of parallel strands insulated from one another (e.g., by an insulating sleeve) along the length of the wire. Thus, the conductor 1355 is referred to herein as litz wire conductor 1355 or litz conductor 1355. Litz wire conductor 1355 creates a weave pattern 1360 within circuit board 1350. Litz wire conductor 1355 and weave pattern 1360 thereof may extend around holes 1365 of circuit board 1350. The size of the holes 1210, 1325, 1365 may be larger than the thickness of the middle leg 750 of the "E" shaped core as shown in fig. 7A, such that the middle leg 750 may pass through the holes 1210, 1325, 1365. Litz wire conductor 1355 of litz PCB winding 1302 may include layer(s) of weave pattern 1360, e.g., as described in further detail below with respect to fig. 14-16.

The solid PCB winding 1300 and the litz PCB winding 1302 provide different AC resistances that are related to the acceptable or desired frequency of current excitation. Higher frequencies will result in thinner skin depths, which will affect the corrected penetration rate and affect skin and proximity effect factors. The penetration, switching frequency, number of turns and/or number of PCB winding layers can affect the resistance factor.

Litz wire conductor 1355 used in litz PCB winding 1302 may reduce and/or eliminate the AC resistance of the inductor as compared to solid circular wire conductor 1315 of solid wire PCB winding 1300. Litz wire conductor 1355 may be manufactured by twisting multiple wires to reduce skin and proximity effects. Regarding the skin effect, because each strand has a much smaller cross-sectional area, the skin thickness is negligible compared to the diameter of litz wire conductor 1355. The proximity effect in litz conductor 1355 is offset by the confinement of the magnetic field in the adjacent strands by the evenly distributed strands. Thus, litz wire conductor 1355 reduces skin and proximity effects and reduces AC losses compared to solid wire windings, whether wound (as in fig. 7A) or embedded in a solid wire PCB (as in fig. 13A). However, the solid wire PCB winding 1300 may be manufactured with less complexity when compared to the litz PCB winding 1302.

Referring to fig. 14, a three-dimensional (3D) routed litz PCB winding 1400 is shown that includes litz wire conductor 1355. In fig. 14, a 3D litz PCB routing technique is employed to provide litz wire conductor 1355 with pattern 1360 described above with respect to fig. 13B. The pattern 1360 is formed of a plurality of strands that collectively form the litz wire conductor 1355. The 3D wired PCB winding 1400 provides benefits such as inherent insulation capability, ease of assembly, and high window space utilization, and the litz wire provides benefits such as reduced ac losses, as described above. The 3D litz PCB routing technique uses a litz structure of circular twisted conductors embedded in and routed through multiple layers of the circuit board 1350 (although the circuit board 1350 is not shown in fig. 14 to highlight the litz structure). The 3D litz PCB is routed taking into account the magnetic field generated by the strands of litz conductor 1355. For example, each strand of litz conductor in circuit board 1350 can be threaded uniformly through all layers of circuit board 1350 to cancel out the adjacent magnetic fields of adjacent strands of litz conductor 1355. In addition, the length of each strand of litz conductor 1355 can be substantially the same to avoid non-uniformity of the magnetic field between the different strands.

The 3D litz PCB routing technique can be extended and applied to a variable number of strands and layers to better simulate round litz wire. In order to uniformly route through multiple layers of the PCB, the litz PCB may be composed of six types of routing patterns, including a left-to-right pattern, a right-to-left pattern, an external via up pattern, an external via down pattern, an internal via up pattern, and an internal via down pattern. The right-to-left and left-to-right modes are wires (strands) routed directly from one side of the copper layer to the other. The outer vias are distributed in an upward and downward pattern on both sides of the edge of the circuit board to connect between adjacent copper layers. When the PCB routing method includes more than 4 layers, an internal via up and an internal via down pattern is added to the 3D litz PCB routing technology. The internal via up and internal via down patterns are distributed inside the PCB wiring away from the edge to connect adjacent copper layers. The particular thickness, number of strands, number of layers, and trace width of litz conductor 1355 of the copper wire may be selected to vary and achieve the desired performance and characteristics of litz PCB winding 1302 in combination with 3D litz PCB winding 1400. For example, the number of strands and the width of each strand (trace) can affect proximity effects and window space utilization, and can reduce resistance factors and AC losses. In general, the greater the number of strands, the smaller the width of each strand (trace), resulting in less impact of proximity effects, lower window space utilization, lower resistance, and lower AC losses.

Still referring to fig. 14, the 3d litz PCB wire (litz conductor 1355) includes a solid winding 1440 around four corner edges 1445. The solid winding angle allows the strands (or traces) between the two solid angle edges to have the same length of litz wire. When the traces reach the edge of the PCB printed inductor, vias and/or electrical connections between the copper layers will help the traces switch layers and go to another symmetrical diagonal direction. The copper layer may be designed according to skin depth to avoid the circular litz wire conductor from being affected by skin effects from the top and bottom surfaces of the litz PCB winding. For example, the thickness of the copper trace may be less than twice the skin depth.

Still referring to fig. 14, each layer of 3d litz PCB wiring includes solid terminal pads 1455 and half holes 1460. Solid terminal pads 1455 and half holes 1460 of different layers are aligned and connect different layers of the PCB windings of the circuit board. Two solid terminal pads 1455 extend laterally from the 3D litz wire between two corner edges 1445. Two solid terminal pads 1455 are separated by a gap 1465. Distal ends 1470 of two solid terminal pads 1455 include half-holes 1460, which half-holes 1460 extend outwardly away from two solid terminal pads 1455 in opposite directions. Half holes 1460 provide alignment between layers of the winding board while establishing electrical connections. Solid terminal pads 1455 and half holes 1460 are capable of balancing the winding length of the 3D litz wire per turn.

The multiple layers of litz conductor 1355 shown in fig. 14 provide an electrically conductive loop or winding for the inductor beginning at a first node (first stack of half-hole 1460 and terminal pad 1455) and ending at a second node (other stack of half-hole 1460 and terminal pad 1455). When multiple litz PCB windings 1302 are included in the inductor, each litz PCB winding 1320 includes a litz conductor 1355 such as shown in fig. 14, the node of each litz conductor 1355 can be connected to the node of another litz conductor 1355 to connect in series the conductive loops formed by the individual litz conductors 1355 to form a multi-loop winding (across the stacked litz PCB windings 1302). The terminal pairs on the solid wire PCB winding 1300 of fig. 13A may similarly be used to series the conductive loops provided by the embedded windings of the PCB 1300, forming a multi-loop winding (across the stacked solid PCB winding 1300). In some examples, a plurality of litz conductors 1355 connected in series are included within a single circuit board, providing a litz PCB winding with multiple loop windings of litz conductors. In some examples, every second layer of litz conductor 1355 forms a "loop," and the two loops (two layers per set) are connected in series. Thus, in this arrangement, the litz PCB winding with the litz conductor 1355 having four layers may be a double loop winding. In other embodiments, litz conductor 1355 is provided with more or fewer layers connected in series to provide litz PCB windings with more or fewer loops.

Referring now to fig. 15, a 3D litz wire 1500 is illustrated that includes 40 litz wires and four layers of litz wire. The 3D litz wire 1500 is an enlarged view of a cross section of the litz conductor 1355 of fig. 13B and 14. Three representative strands of the top layer of wiring 1500 are identified as strands 1501, 1502 and 1503. In fig. 15, the strands of the top and third layers, including strands 1501, 1502, and 1503, extend generally diagonally upward and leftward (when starting from the lower portion 1504 of the wire 1500). Instead, the strands of the bottom and second layers generally extend upward and rightward (when starting from the lower portion 1504 of the wire).

Referring now to fig. 16, a wiring 1500 is shown divided into four layers thereof. Top layer 1505 includes left-to-right pattern 1510 and via up pattern 1515 between winding edges 1520. The second layer 1525 includes a right-to-left pattern 1530 and a via down pattern 1535 between the winding edges 1520. The third layer 1540 includes a left-to-right pattern 1510 and a via up pattern 1515 between the winding edges 1520. Bottom layer 1545 includes right-to-left pattern 1530 and via down pattern 1535 between winding edges 1520. Solid terminal pads 1455 and half holes 1460 pair Ji Lici route four layers of 1500. The four layers of litz wire 1500 form the litz conductor 1355 of the litz PCB winding 1302 as shown in fig. 13B. Although the example of fig. 16 includes four layers, in some examples, litz PCB windings are formed using multiple or fewer layers of litz conductors 1355.

Fig. 17 illustrates resistance factor measurements of different layers of litz PCB winding 1302 and solid PCB winding 1300 at different frequencies. The proximity effect affects copper loss and the resistance factor increases with the number of stacked layers. From the results of the illustration, litz PCB windings or litz wire structures have a smaller resistance factor, which is more suitable for high frequency applications, especially when stacking multiple layers of PCB windings to form an inductor. For example, at low to high frequencies, single and double layer litz wire PCBs have lower resistance factors than conventional litz wire and single layer solid PCB windings, and three and four layer litz wire PCBs have much lower resistance factors than comparable layer solid PCB windings.

Fig. 18 and 19 illustrate plotted data points based on experimental tests for different inductor designs for inductor (power) loss, cost and volume, for use in power converters with critical soft switching conditions of high frequency (100 kHz-1 MHz) and high current ripple (50A). The reference commercial inductor cannot adequately handle these conditions due to high losses and temperature rise. Referring to the "EE" shaped core 700 of fig. 7A with the litz wire inductor 715, the wire inductor has relatively low losses, higher cost, and higher bulk. The "EE" shaped core 700 with litz PCB windings 760 illustrated in fig. 7B has a relatively low volume, high losses, and low cost. The "II" shaped core 1000 and the "EA" shaped core 900 have relatively low volume, low cost, and high losses.

Fig. 18 illustrates a comparison of inductor loss versus inductor volume. A commercial inductor is shown compared to different core shapes, turns and winding types. Litz PCB windings 1302 and solid PCB windings 1300 on "II" shaped core 1000 and "EA" shaped core 900 exhibit a smaller loss-per-inductance volume.

Fig. 19 illustrates a comparison of inductor losses versus the cost of manufacturing an inductor. A commercial inductor is shown compared to different core shapes, turns and winding types. Litz PCB windings 1302 and solid PCB windings 1300 on "II" shaped core 1000 and "EA" shaped core 900 exhibit lower cost per inductance loss.

Combined PCB with converter circuit and LC filter inductor

In some embodiments, one or more components of the power converter circuit are located (e.g., embedded, mounted, etc.) on a Printed Circuit Board (PCB). These one or more components may include, for example, the electronic controller 105 or a portion thereof (e.g., the processor 145, the memory 150, one or more gate drivers, etc.), the power converter 115 (e.g., one or more power switching elements that make up the power converter 115), or a combination thereof. In some examples, the inductors of LC filter 120 are located on the same PCB in conjunction with these one or more components of the power converter circuit, resulting in a combined PCB. For example, the PCB may include at least one turn of the coil portion of the inductor (whether as a solid wire, as a litz conductor, or another form) and may be sandwiched between two "I" cores (i.e., as part of an inductor having an "II" shaped core, as discussed in fig. 10A and 10B), or otherwise integrated with another core shape (see, e.g., EE, EI, and EA cores of fig. 7A-10B, and as described above).

Referring to fig. 20, a single PCB1900 may include an inductor 1905 combined with one or more components. For example, one or more individual PCBs including the inductor 1905, the controller 1910, and/or the gate driver 1915/silicon carbide MOSFET 1920 may be replaced with a single PCB1900, with one or more of the inductor 1905 and the controller 1910, the gate driver 1915, the silicon carbide MOSFET 1920, the input capacitor 1925, the DC input 1930, the voltage sensor 1935, the current sensor 1940, the DC output 1945, or the output capacitor 1950 located on the single PCB 1900. The inductor 1905 includes a winding portion as embedded in the PCB1900, e.g., one of the embedded windings previously described, such as the solid winding 1315 (of fig. 13A) or the litz conductor 1355 (of fig. 13B). Thus, PCB1900 may be considered, at least in part, a solid PCB winding or litz PCB winding of inductor 1905. Inductor 1905 further includes, for example, a core having a "II" shape, an "EA" shape, an "EI" shape, or an "EE" shape as a core. Thus, PCB1900 may include holes (such as holes 1325 or 1365 shown in fig. 13A-13B) that allow and receive the legs of the core (e.g., in the case of an "E" shaped base). The combined single PCB1900 may provide a more compact power converter with increased power density and reduced material that would otherwise exist for a multi-PCB implementation. In some examples, the coil portion of the inductor includes one or more additional PCBs stacked with the combined PCB to provide additional turns. These additional PCBs may be located on one side of the combined PCB (e.g., stacked on top of or below the combined PCB), or may be located on both sides of the combined PCB. In either case, the turn(s) of each PCB are conductively coupled with the turn(s) of the other PCBs in the stack, and the turns of the PCBs are aligned or nearly concentric. For example, see the PCB stacks (and the number of turns of the corresponding inductors) illustrated in fig. 7B, 8B, 9B, and 10B.

As provided herein, an inductor for an LC filter in a power converter may have various characteristics and properties related to the winding portion and core, including size, shape, number of turns, winding type, and the like. The particular combination of these characteristics may be selected to meet the requirements or preferences of a particular design. Some considerations of such designs are now provided. Typically, the inductance decreases linearly with the current level and the current increases because magnetic energy is proportional to the square of the current. The inductance of the inductor of the LC filter 120 may be designed around the area product of energy-1/2 (Li 2) 3/4.

The proportional relationship may be provided by the following equation describing the inductor (and magnetics) law:

Wherein a _w and a _i are the winding and iron region, respectively; l is inductance, I _p、I_RMS and J _RMS are peak current, RMS current and current density, respectively; b _s is saturation induction; v _l is the inductor volume. In addition, in the case of the optical fiber,

Where E _l is the energy stored in the inductor.

Thus, changing the number of turns, for example increasing the number of parallel or series turns, results in a different level of current or inductance. As used herein, an inductor, "turn" may also be referred to as a conductor loop.

Fig. 21 illustrates a process 2100 for power conversion. Process 2100 is described as being performed by power converter system 100, power converter system 100 is implemented as power converter 115 with power converter 200, and power converter system 100 includes one of the disclosed inductors provided herein as a switch-side inductor of filters 120, 245, 308 (or an inductor of each phase shown in fig. 3). However, in some embodiments, process 2100 may be implemented by another power converter system or by power converter system 100 using another power converter as power converter 115. Further, although the blocks of process 2100 are illustrated in a particular order, in some embodiments one or more blocks may be performed in part or in full parallel, may be performed in an order different than illustrated in fig. 21, or may be bypassed.

In block 2105, a power converter (e.g., power converter system 100) including a power switching element receives input power. For example, referring to fig. 2, a DC voltage terminal (e.g., DC voltage terminal 220) receives an input DC voltage, where the DC voltage terminal includes a positive DC terminal 222 and a negative DC terminal 224 on the DC side of the power converter. The input DC voltage may be provided by a DC source such as a battery, a capacitor, a supercapacitor, a DC power supply from a rectified AC source (e.g., AC grid power converted to DC power by a diode bridge rectifier), and the like. Alternatively, an interface terminal (e.g., interface terminal 225) receives an AC input voltage. The AC input voltage may be provided by an AC source, such as a power grid, an AC generator (e.g., an engine-driven generator), or the like.

In block 2110, a controller (e.g., controller 105) drives a pair of power switching elements to convert the received input power. In the case where the received input power is DC power, the power switching element converts the DC power to AC power for output via the interface terminal 225. In the case where the received input power is AC power, the power switching element converts the AC power to DC power for output via the DC terminal 220. In some examples, the controller 105 drives the power switching elements with a Variable Frequency Critical Soft Switch (VFCSS) as described above. To drive the power switching element, the controller 105 outputs a PWM control signal to a gate terminal of the power switching element. To generate the PWM control signal to drive the power switching elements (e.g., switches 235, 240), the controller 105 may sense or estimate the operating characteristics of the power converter and increase or decrease the duty cycle (and, in the case of VFCSS, the frequency) of the PWM control signal accordingly. For example, the controller 105 may implement a proportional-integral-derivative (PID) controller that receives an input voltage command (reference voltage) of the converter and a measured voltage at the output of the converter (e.g., at the interface terminal 225). The PID controller can then generate a reference current signal based on the difference between the reference voltage and the measured voltage using standard PID techniques. Typically, the reference current signal will increase if the measured voltage is lower than the reference voltage, and conversely, the reference current signal will decrease if the measured voltage is higher than the reference voltage. The reference current may then be converted to a reference duty cycle value (e.g., a value between 0-100%) that indicates the percentage of each switching cycle that the upper switch (M1) 135 should be open and closed, and likewise, the percentage of each switching cycle that the lower switch (M2) 140 should be closed. In general, within certain operating boundaries, the duty cycle of the upper switch (M1) 135 increases with increasing reference current. The controller 105 (or its gate driver) may then generate a corresponding PWM control signal according to the reference duty cycle. The PID controller is just one example of a control scheme that generates control signals to drive the power switching elements. In other examples, in block 2110, the controller 105 implements other control schemes, such as cascaded PID control, state-based control, model Predictive Control (MPC), or another tuning control scheme, to drive the power switching elements of the modified converter 210. For example, controller 105 may implement VFCSS using another control scheme.

In block 2115, an LC filter (e.g., LC filter 120, 245, 308) including an inductor and a capacitor coupled to the first side of the power converter filters the power signal on the first side of the power converter. The power signal received by the LC filter may have a current ripple of at least 200% of the peak-to-peak ripple relative to the local average current.

The switch-side inductor of the LC filter (e.g., switch-side inductor 250 of LC filter 120, 245, 308) may be implemented as one of the inductors provided herein, such as one of the inductors comprising a PCB winding, whether a solid PCB winding (see e.g., fig. 13A) or a litz PCB winding (see e.g., fig. 13B). Depending on the control or driving of the power switching element, the filtered output voltage may be an AC voltage provided to the interface terminal 225 or a DC voltage provided to the DC terminal 220.

As described above, in some examples, LC filter 120, 245 includes another inductor coupled between filter node 260 and positive interface terminal 227, thereby providing an LCL filter. Additionally, in some examples, the LC filter further includes an upper capacitor (see upper capacitor 215 of fig. 2) that can reduce the ripple current by providing a path for the ripple current to propagate between the DC terminal and the interface terminal, and eliminate at least a portion of the differential-mode current ripple between the DC terminal and the interface terminal. In some examples, each power switching element (e.g., upper switch 235 and lower switch 240) includes a drain-source capacitor (C _DS) coupled across respective source and drain terminals of switches 235, 240 (see, e.g., capacitors 265a-b of fig. 2). In some examples, the LC filter of process 2100 is included in a combined PCB, as provided with respect to fig. 20.

A controller device (e.g., a processor-based computing device) may facilitate performing the various techniques and operations described herein. Such controller devices may include processor-based devices, such as computing devices, which may include a Central Processing Unit (CPU) or a processing core. In addition to the CPU or processing core, the system includes a main memory, a cache memory, and bus interface circuitry. The controller may include a memory storage device, such as a hard disk drive (solid state drive or other type of hard drive) or flash drive associated with a computer system. The controller device may further comprise a keyboard or keypad or some other user input interface, and a monitor, such as an LCD (liquid crystal display) monitor, which may be placed where the user has access to them.

The controller device is configured to facilitate implementation of, for example, a voltage converter (e.g., by controlling switching devices of, for example, a non-isolated three-phase DC/AC voltage converter system). Thus, the storage device may include a computer program product that, when executed on a controller device (which may be a processor-based device as described), causes the processor-based device to perform operations in order to implement the programs and operations described herein. The controller device may further include peripheral devices implementing input/output functions. Such peripheral devices may include, for example, a flash drive (e.g., a removable flash drive) or a network connection (e.g., implemented using a USB port and/or a wireless transceiver) for downloading relevant content to the connected system. Such peripheral devices may also be used to download software containing the computer instructions for the purpose of the general operation of the corresponding systems/devices. Alternatively and/or additionally, in some embodiments, dedicated logic circuits, such as FPGAs (field programmable gate arrays), ASICs (application specific integrated circuits), DSP processors, graphics Processing Units (GPUs), application Processing Units (APUs), etc., may be used in the implementation of the controller device. Other modules that may be included in the controller device may include a user interface to provide or receive input and output data. The controller device may include an operating system.

Computer programs (also known as programs, software applications or code) include machine instructions for a programmable processor, and can be implemented in a high-level procedural and/or object-oriented programming language, and/or in assembly/machine language. As used herein, the term "machine-readable medium" refers to any non-transitory computer program product, apparatus and/or device (e.g., magnetic discs, optical disks, memory, programmable Logic Devices (PLDs)) used to provide machine instructions and/or data to a programmable processor, including a non-transitory machine-readable medium that receives machine instructions as a machine-readable signal.

In some embodiments, any suitable computer readable medium may be used to store instructions for performing the processes/operations/programs described herein. For example, in some embodiments, the computer readable medium may be transitory or non-transitory. For example, the non-transitory computer readable medium may include the following media, such as: magnetic media (such as hard disk, floppy disk, etc.), optical media (such as compact disk, digital video disk, blu-ray disk, etc.), semiconductor media (such as flash memory, electrically Programmable Read Only Memory (EPROM), electrically Erasable Programmable Read Only Memory (EEPROM), etc.), any suitable medium that is not transitory or that does not have any durable appearance during transmission, and/or any suitable tangible medium. As another example, a transitory computer-readable medium may include signals on a network, wires, conductors, optical fibers, circuits, any suitable medium that is transitory during transmission and that does not have any durable appearance, and/or any suitable intangible medium.

Although specific embodiments have been disclosed herein in detail, this has been done by way of example for purposes of illustration only and is not intended to be limiting with respect to the scope of the appended claims. Features of the disclosed embodiments may be combined, rearranged, etc., within the scope of the invention to produce additional embodiments. Some other aspects, advantages, and modifications are considered to be within the scope of the claims provided below. The claims presented represent at least some of the embodiments and features disclosed herein. Other unattended embodiments and features are also contemplated.

Further example

Example 1: a method, apparatus, and/or non-transitory computer readable medium storing processor-executable instructions for a non-isolated power converter system, the system comprising: a power converter including a power switching element; a controller configured to drive the power switching element to convert the received power and output the converted power, the controller configured to drive the power switching element using a variable frequency soft switch; and a filter coupled to the first side of the power converter to filter the power signal on the first side of the power converter, the power signal received by the filter having a current ripple that is at least 200% of a peak-to-peak ripple relative to the local average current, wherein the inductor comprises a core portion and a winding portion, wherein the winding portion comprises windings embedded in the printed circuit board.

Example 2: the method, apparatus, and/or non-transitory computer readable medium of example 1, wherein each loop of the winding is a wire conductor having a solid cross-section.

Example 3: the method, apparatus, and/or non-transitory computer-readable medium of any one of examples 1-2, wherein the windings embedded in the printed circuit board form a litz PCB, wherein the windings comprise multiple layers of parallel strands routed in the printed circuit board.

Example 4: the method, apparatus, and/or non-transitory computer readable medium of any one of examples 1 to 3, wherein the litz PCB comprises at least one or more layers of parallel strands, and each of the parallel strands is a conductive trace.

Example 5: the method, apparatus, and/or non-transitory computer-readable medium of any one of examples 1-4, wherein the winding portion comprises one or more additional litz PCBs, each additional litz PCB comprising additional windings comprising multiple layers of parallel strands routed in an additional printed circuit board.

Example 6: the method, apparatus, and/or non-transitory computer-readable medium of any one of examples 1-5, wherein the core comprises a first core and a second core located on opposite sides of the winding portion, wherein the first core and the second core comprise planar surfaces facing the conductor loop and substantially parallel to the printed circuit board.

The method, apparatus, and/or non-transitory computer-readable medium of example 7, wherein the core comprises a first core opposite the open air portion, the first core having a base portion and three legs extending from the base portion, wherein a middle leg of the three legs extends through an opening defined by the conductor loop.

Example 8: the method, apparatus, and/or non-transitory computer-readable medium of any one of examples 1-7, wherein the printed circuit board further comprises one or more of the following located thereon: a controller, or one or more of the power switching elements.

Example 9: the method, apparatus, and/or non-transitory computer readable medium of any one of examples 1-8, wherein the first side of the power converter is one selected from the group of a DC output side for DC/DC conversion, an AC output side for DC/AC inversion, and an AC input side for AC/DC rectification.

Example 10: a method, apparatus, and/or non-transitory computer readable medium storing processor-executable instructions for a power conversion method, the method comprising: receiving input power by a power converter comprising a power switching element; driving, by a controller, the power switching element to convert the received input power to output converted power, the controller configured to drive the power switching element using a variable frequency soft switch; and filtering the power signal on the first side of the power converter by an LC filter coupled to the first side of the power converter comprising an inductor and a capacitor, the power signal received by the filter having a current ripple of at least 200% of a peak-to-peak ripple relative to a local average current, wherein the inductor comprises a core portion and a winding portion, wherein the winding portion comprises windings embedded in a printed circuit board.

Example 11: a method, apparatus, and/or non-transitory computer readable medium storing processor-executable instructions for an inductor in a non-isolated power converter system, the inductor comprising: a core; a winding portion forming an inductor with the core, the winding portion comprising a winding embedded in a printed circuit board and having a first terminal and a second terminal, the winding embedded in the printed circuit board forming a litz PCB, wherein the winding comprises multiple layers of parallel strands routed in the printed circuit board.

Example 12: the method, apparatus, and/or non-transitory computer-readable medium of example 11, wherein the litz PCB comprises at least two layers of parallel strands, and each of the parallel strands is a conductive trace.

Example 13: the method, apparatus, and/or non-transitory computer-readable medium of any one of examples 11 to 12, wherein the winding portion comprises one or more additional litz PCBs, each additional litz PCB comprising additional windings comprising multiple layers of parallel strands routed in an additional printed circuit board.

Example 14: the method, apparatus, and/or non-transitory computer-readable medium of any one of examples 11-13, wherein the core comprises a first core and a second core located on opposite sides of the winding portion, wherein the first core and the second core comprise planar surfaces facing the conductor loop and substantially parallel to the printed circuit board.

Example 15: the method, apparatus, and/or non-transitory computer-readable medium of any one of examples 11-14, wherein the core comprises a first core opposite the open air portion, the first core having a base portion and three legs extending from the base portion, wherein a middle leg of the three legs extends through an opening defined by the conductor loop.

Example 16: the method, apparatus, and/or non-transitory computer-readable medium of any of examples 11-15, wherein the inductor is part of an LC filter that filters a power signal of the power converter, and wherein the printed circuit board further comprises one or more of the following located thereon: one or more of the power switching elements of the power converter, or a controller configured to drive the one or more power switching elements of the power converter.

Example 17: the method, apparatus, and/or non-transitory computer readable medium of any one of examples 11 to 16, wherein the power converter is one selected from the group of a DC/DC converter, a DC/AC inverter, and an AC/DC rectifier.

Example 18: a method, apparatus, and/or non-transitory computer readable medium storing processor-executable instructions for an inductor in a non-isolated power converter system, the inductor comprising: a winding portion including a winding embedded in the printed circuit board, the winding forming a conductor loop and including a first terminal and a second terminal; a core forming an inductor with the winding portion, the core comprising a first core and a second core on opposite sides of the winding portion, wherein the first core and the second core comprise planar surfaces facing the conductor loop and substantially parallel to the printed circuit board.

Example 19: the method, apparatus, and/or non-transitory computer-readable medium of example 18, wherein the core comprises a first core and a second core on opposite sides of the winding portion, wherein the plurality of printed circuit boards are sandwiched between the first core and the second core.

Example 20: the method, apparatus, and/or non-transitory computer readable medium of any of examples 18-19, wherein the conductor loop of the winding is a wire conductor having a solid cross-section.

Example 21: the method, apparatus, and/or non-transitory computer readable medium of any one of examples 18 to 20, wherein the windings embedded in the printed circuit board form a litz PCB, wherein the windings comprise multiple layers of parallel strands routed in the printed circuit board.

Example 22: the method, apparatus, and/or non-transitory computer readable medium of any one of examples 18 to 21, wherein the litz PCB comprises at least four layers of parallel strands, and each of the parallel strands is a conductive trace.

Example 23: the method, apparatus, and/or non-transitory computer-readable medium of any one of examples 18 to 22, wherein the winding portion comprises one or more additional litz PCBs, each additional litz PCB comprising additional windings comprising multiple layers of parallel strands routed in an additional printed circuit board.

Example 24: the method, apparatus, and/or non-transitory computer-readable medium of any of examples 18-23, wherein the inductor is part of an LC filter that filters a power signal of the power converter, and wherein the printed circuit board further comprises one or more of the following located thereon: one or more of the power switching elements of the power converter, or a controller configured to drive the one or more power switching elements of the power converter.

Example 25: the method, apparatus, and/or non-transitory computer readable medium of any one of examples 18 to 24, wherein the power converter is one selected from the group of a DC/DC converter, a DC/AC inverter, and an AC/DC rectifier.

Example 26: a method, apparatus, and/or non-transitory computer readable medium storing processor-executable instructions for an inductor in a non-isolated power converter system, the inductor comprising: a winding portion including a winding embedded in the printed circuit board, the winding forming a conductor loop and including a first terminal and a second terminal; a core forming an inductor with the winding portion, the core comprising a first core opposite the open air portion, the first core having a base portion and three legs extending from the base portion, wherein a middle leg of the three legs extends through an opening defined by the conductor loop.

Example 27: the method, apparatus, and/or non-transitory computer-readable medium of example 26, wherein an outermost leg of the first core is parallel to a middle leg of the three legs, the outermost leg having a different thickness than the middle leg.

Example 28: the method, apparatus and/or non-transitory computer readable medium of any one of examples 26 to 27,

Example 29: the method, apparatus, and/or non-transitory computer readable medium of any of examples 26 to 28, wherein the conductor loop of the winding is a wire conductor having a solid cross-section.

Example 30: the method, apparatus, and/or non-transitory computer readable medium of any one of examples 26 to 29, wherein the windings embedded in the printed circuit board form a litz PCB, wherein the windings comprise multiple layers of parallel strands routed in the printed circuit board.

Example 31: the method, apparatus, and/or non-transitory computer readable medium of any one of examples 26 to 30, wherein the litz PCB comprises at least four layers of parallel strands, and each of the parallel strands is a conductive trace.

Example 32: the method, apparatus, and/or non-transitory computer-readable medium of any one of examples 26 to 31, wherein the winding portion comprises one or more additional litz PCBs, each additional litz PCB comprising additional windings comprising multiple layers of parallel strands routed in an additional printed circuit board.

Example 33: the method, apparatus, and/or non-transitory computer-readable medium of any of examples 26-32, wherein the inductor is part of an LC filter that filters a power signal of the power converter, and wherein the printed circuit board further comprises one or more of the following located thereon: one or more of the power switching elements of the power converter, or a controller configured to drive the one or more power switching elements of the power converter.

Example 34: the method, apparatus, and/or non-transitory computer readable medium of any one of examples 26 to 33, wherein the power converter is one selected from the group of a DC/DC converter, a DC/AC inverter, and an AC/DC rectifier.

Example 35: a method, apparatus, and/or non-transitory computer readable medium storing processor-executable instructions for a non-isolated power converter system, the system comprising: a power converter including a power switching element; a controller configured to drive the power switching element to convert the received power and output the converted power. A filter including an inductor and a capacitor, the filter coupled to the first side of the power converter to filter a power signal on the first side of the power converter, wherein the inductor includes a core portion and a winding portion; and a printed circuit board on which the windings of the winding portion are embedded, and on which one or more of the following are provided: a controller, or one or more of the power switching elements.

Example 36: the method, apparatus, and/or non-transitory computer-readable medium of example 35, wherein each loop of the winding is a wire conductor having a solid cross-section.

Example 37: the method, apparatus, and/or non-transitory computer-readable medium of any one of examples 35 to 36, wherein the windings embedded in the printed circuit board form a litz PCB, wherein the windings comprise multiple layers of parallel strands routed in the printed circuit board.

Example 38: the method, apparatus, and/or non-transitory computer-readable medium of any one of examples 35 to 37, wherein the litz PCB comprises at least four layers of parallel strands, and each of the parallel strands is a conductive trace.

Example 39: the method, apparatus, and/or non-transitory computer-readable medium of any one of examples 35 to 38, wherein the winding portion comprises one or more additional litz PCBs, each additional litz PCB comprising additional windings comprising multiple layers of parallel strands routed in an additional printed circuit board.

Example 40: the method, apparatus, and/or non-transitory computer-readable medium of any one of examples 35-39, wherein the core comprises a first core and a second core located on opposite sides of the winding portion, wherein the first core and the second core comprise planar surfaces facing the conductor loop and substantially parallel to the printed circuit board.

Example 41: the method, apparatus, and/or non-transitory computer-readable medium of any one of examples 35-40, wherein the core comprises a first core opposite the open air portion, the first core having a base portion and three legs extending from the base portion, wherein a middle leg of the three legs extends through an opening defined by the conductor loop.

Example 42: the method, apparatus, and/or non-transitory computer-readable medium of any one of examples 35 to 41, wherein the printed circuit board further comprises one or more of the following located thereon: a controller, or one or more of the power switching elements.

Example 43: the method, apparatus, and/or non-transitory computer-readable medium of any one of examples 35 to 42, wherein the power converter is one selected from the group of a DC/DC converter, a DC/AC inverter, and an AC/DC rectifier.

Example 44: a method, apparatus, and/or non-transitory computer readable medium storing processor-executable instructions for a power conversion method, the method comprising: receiving input power by a power converter comprising a power switching element; driving, by a controller, a power switching element to convert received input power to output converted power, one or more of: (i) A controller, or (ii) one or more of the power switching elements located on the printed circuit board; the power signal on the first side of the power converter is filtered by an LC filter coupled to the first side of the power converter comprising an inductor and a capacitor, wherein the inductor comprises a core portion and a winding portion, wherein the winding portion comprises windings embedded in a printed circuit board.

Example 45: the method, apparatus, and/or non-transitory computer-readable medium of example 44, wherein driving, by the controller, the power switching element to convert the received input power to output converted power comprises at least one selected from the group consisting of: converting input power from a first DC voltage level to a second DC voltage level for outputting converted power, wherein the first side of the power converter is a DC output side; converting input power from DC to AC for outputting converted power, wherein the first side of the power converter is an AC output side; or converting input power from AC to DC for output of converted power, wherein the first side of the power converter is the AC input side.

Claim (modification according to treaty 19)

1. A non-isolated power converter system, the system comprising:

A power converter including a power switching element;

A controller configured to drive the power switching element to convert received power and output the converted power, the controller configured to drive the power switching element using a variable frequency soft switch; and

A filter comprising an inductor and a capacitor, the filter coupled to a first side of the power converter to filter a power signal on the first side of the power converter, the power signal received by the filter having a current ripple that is at least 200% of a peak-to-peak ripple relative to a local average current,

Wherein the inductor comprises a core portion and a winding portion, wherein the winding portion comprises windings embedded in a printed circuit board.

2. The non-isolated power converter system of claim 1, wherein each loop of the winding is a wire conductor having a solid cross-section.

3. The non-isolated power converter system of claim 1, wherein the windings embedded in the printed circuit board form a litz PCB, wherein the windings comprise multiple layers of parallel strands routed in the printed circuit board.

4. The non-isolated power converter system of claim 3, wherein the litz PCB comprises at least two layers of parallel strands, and each of the parallel strands is a conductive trace.

5. The non-isolated power converter system of claim 3, wherein the winding portion comprises one or more additional litz PCBs, each additional litz PCB comprising additional windings comprising multiple layers of parallel strands routed in additional printed circuit boards.

6. The non-isolated power converter system of claim 1, wherein the core comprises a first core and a second core on opposite sides of the winding portion, wherein the first core and the second core comprise planar surfaces facing a conductor loop and substantially parallel to the printed circuit board.

7. The non-isolated power converter system of claim 1, wherein the core includes a first core opposite an open air portion, the first core having a base portion and three legs extending from the base portion, wherein a middle leg of the three legs extends through an opening defined by a conductor loop.

8. The non-isolated power converter system of claim 1, wherein the printed circuit board further comprises one or more of the following located thereon:

The controller is or

One or more of the power switching elements.

9. The non-isolated power converter system of claim 1, wherein the first side of the power converter is one selected from the group of a DC output side for DC/DC conversion, an AC output side for DC/AC inversion, and an AC input side for AC/DC rectification.

10. A method of power conversion, the method comprising:

receiving input power by a power converter comprising a power switching element;

driving the power switching element by a controller to convert received input power to output converted power, the controller configured to drive the power switching element using a variable frequency soft switch; and

Filtering a power signal on a first side of the power converter by an LC filter coupled to the first side of the power converter comprising an inductor and a capacitor, the power signal received by the filter having a current ripple of at least 200% of a peak-to-peak ripple relative to a local average current,

11. The method of claim 10, wherein each loop of the winding is a wire conductor having a solid cross-section.

12. The method of claim 10, wherein the windings embedded in the printed circuit board form a litz PCB, wherein the windings comprise multiple layers of parallel strands routed in the printed circuit board.

13. The method of claim 12, wherein the litz PCB comprises at least two layers of parallel strands, and each of the parallel strands is a conductive trace.

14. The method of claim 12, wherein the winding portion comprises one or more additional litz PCBs, each additional litz PCB comprising an additional winding comprising multiple layers of parallel strands routed in an additional printed circuit board.

15. The method of claim 10, wherein the core comprises a first core and a second core on opposite sides of the winding portion, wherein the first core and the second core comprise planar surfaces facing a conductor loop and substantially parallel to the printed circuit board.

16. The method of claim 10, wherein the core comprises a first core opposite an open air portion, the first core having a base portion and three legs extending from the base portion, wherein a middle leg of the three legs extends through an opening defined by a conductor loop.

17. The method of claim 10, wherein the printed circuit board further comprises one or more of the following located thereon:

The controller is or

One or more of the power switching elements.

18. The method of claim 10, wherein driving the power switching element by the controller to convert the received input power to output converted power comprises at least one selected from the group of:

Converting the input power from a first DC voltage level to a second DC voltage level for the output converted power, wherein the first side of the power converter is a DC output side,

Converting the input power from DC to AC for the output converted power, wherein the first side of the power converter is an AC output side, or

Converting the input power from AC to DC for the output converted power, wherein the first side of the power converter is an AC input side.

19. An inductor for a filter in a non-isolated power converter system, the inductor comprising:

A core; and

A winding portion forming an inductor with the core, the winding portion comprising a winding embedded in a printed circuit board and having a first terminal and a second terminal, the winding embedded in the printed circuit board forming a litz PCB, wherein the winding comprises multiple layers of parallel strands routed in the printed circuit board.

20. The inductor of claim 19, wherein the litz PCB comprises at least two layers of parallel strands, and each of the parallel strands is a conductive trace.

21. The inductor of claim 19, wherein the winding portion comprises one or more additional litz PCBs, each additional litz PCB comprising an additional winding comprising multiple layers of parallel strands routed in an additional printed circuit board.

22. The inductor of claim 19, wherein the core comprises a first core and a second core on opposite sides of the winding portion, wherein the first core and the second core comprise planar surfaces facing a conductor loop and substantially parallel to the printed circuit board.

23. The inductor of claim 19, wherein the core comprises a first core opposite an open air portion, the first core having a base portion and three legs extending from the base portion, wherein a middle leg of the three legs extends through an opening defined by a conductor loop.

24. The inductor of claim 19, wherein the inductor is part of an LC filter that filters a power signal of a power converter, and wherein the printed circuit board further comprises one or more of the following located thereon:

one or more of the power switching elements of a power converter, or

A controller configured to drive the one or more power switching elements of the power converter.

25. The inductor of claim 19, wherein the power converter is one selected from the group of a DC/DC converter, a DC/AC inverter, and an AC/DC rectifier.

26. An inductor for a filter in a non-isolated power converter system, the inductor comprising:

A winding portion including a winding embedded in a printed circuit board, the winding forming a conductor loop and including a first terminal and a second terminal; and

A core forming an inductor with the winding portion, the core comprising a first core and a second core on opposite sides of the winding portion, wherein the first core and the second core comprise planar surfaces facing the conductor loop and substantially parallel to the printed circuit board.

27. The inductor of claim 26, wherein the core comprises a first core and a second core on opposite sides of the winding portion, wherein a plurality of printed circuit boards are sandwiched between the first core and the second core.

28. The inductor of claim 26, wherein the conductor loop of the winding is a wire conductor having a solid cross-section.

29. The inductor of claim 26, wherein the windings embedded in the printed circuit board form a litz PCB, wherein the windings comprise multiple layers of parallel strands routed in the printed circuit board.

30. The inductor of claim 29, wherein the litz PCB comprises at least two parallel strands, and each of the parallel strands is a conductive trace.

31. The inductor of claim 29, wherein the winding portion comprises one or more additional litz PCBs, each additional litz PCB comprising an additional winding comprising multiple layers of parallel strands routed in an additional printed circuit board.

32. The inductor of claim 26, wherein the inductor is part of an LC filter that filters a power signal of a power converter, and wherein the printed circuit board further comprises one or more of the following located thereon:

one or more of the power switching elements of a power converter, or

33. The inductor of claim 32, wherein the power converter is selected from one of the group of a DC/DC converter, a DC/AC inverter, and an AC/DC rectifier.

34. An inductor for a filter in a non-isolated power converter system, the inductor comprising:

A core forming an inductor with the winding portion, the core comprising a first core opposite an open air portion, the first core having a base portion and three legs extending from the base portion, wherein a middle leg of the three legs extends through an opening defined by the conductor loop.

35. The inductor of claim 34, wherein an outermost leg of the first core is parallel to the middle leg of three legs, the outermost leg having a different thickness than the middle leg.

36. The inductor of claim 34, wherein the conductor loop of the winding is a wire conductor having a solid cross-section.

37. The inductor of claim 34, wherein the windings embedded in the printed circuit board form a litz PCB, wherein the windings comprise multiple layers of parallel strands routed in the printed circuit board.

38. The inductor of claim 37, wherein the litz PCB comprises at least two layers of parallel strands, and each of the parallel strands is a conductive trace.

39. The inductor of claim 37, wherein the winding portion comprises one or more additional litz PCBs, each additional litz PCB comprising an additional winding comprising multiple layers of parallel strands routed in an additional printed circuit board.

40. The inductor of claim 34, wherein the inductor is part of an LC filter that filters a power signal of a power converter, and wherein the printed circuit board further comprises one or more of the following located thereon:

one or more of the power switching elements of a power converter, or

41. The inductor of claim 40, wherein the power converter is selected from one of the group of a DC/DC converter, a DC/AC inverter, and an AC/DC rectifier.

42. A non-isolated power converter system, the system comprising:

A power converter including a power switching element;

a controller configured to drive the power switching element to convert received power and output the converted power;

A filter comprising an inductor and a capacitor, the filter coupled to a first side of the power converter to filter a power signal on the first side of the power converter, wherein the inductor comprises a core portion and a winding portion, and

A printed circuit board on which windings of the winding portion are embedded, and on which one or more of the following are provided:

The controller is or

One or more of the power switching elements.

43. A non-isolated power converter system as in claim 42, wherein each loop of said winding is a wire conductor having a solid cross-section.

44. A non-isolated power converter system as defined in claim 42, wherein said windings embedded in said printed circuit board form a litz PCB, wherein said windings comprise multiple layers of parallel strands routed in said printed circuit board.

45. The non-isolated power converter system of claim 44, wherein said litz PCB comprises at least two layers of parallel strands, and each of said parallel strands is a conductive trace.

46. A non-isolated power converter system as defined in claim 44, wherein said winding section includes one or more additional litz PCBs, each additional litz PCB including additional windings comprising multiple layers of parallel strands routed in additional printed circuit boards.

47. A non-isolated power converter system as in claim 42, wherein said core includes first and second cores on opposite sides of said winding portion, wherein said first and second cores include planar surfaces facing a conductor loop formed by said winding and being substantially parallel to said printed circuit board.

48. A non-isolated power converter system as defined in claim 42, wherein said core includes a first core opposite an open air portion, said first core having a base portion and three legs extending from said base portion, wherein a middle leg of said three legs extends through an opening defined by a conductor loop formed by said windings.

49. A non-isolated power converter system as defined in claim 42, wherein said printed circuit board further comprises one or more of the following located thereon:

The controller is or

One or more of the power switching elements.

50. A non-isolated power converter system as defined in claim 42, wherein said power converter is one selected from the group of a DC/DC converter, a DC/AC inverter, and an AC/DC rectifier.

51. A method of power conversion, the method comprising:

Driving, by a controller, the power switching element to convert the received input power to output converted power, one or more of: (i) In a controller, or (ii) one or more of said power switching elements located on a printed circuit board; and

The power signal on the first side of the power converter is filtered by an LC filter comprising an inductor and a capacitor coupled to the first side of the power converter,

Wherein the inductor comprises a core portion and a winding portion, wherein the winding portion comprises windings embedded in the printed circuit board.

52. The method of claim 51, wherein each loop of the winding is a wire conductor having a solid cross-section.

53. The method of claim 51, wherein the windings embedded in the printed circuit board form a litz PCB, wherein the windings comprise multiple layers of parallel strands routed in the printed circuit board.

54. The method of claim 53, wherein the litz PCB comprises at least two layers of parallel strands, and each of the parallel strands is a conductive trace.

55. The method of claim 53, wherein the winding portion comprises one or more additional litz PCBs, each additional litz PCB comprising additional windings comprising multiple layers of parallel strands routed in an additional printed circuit board.

56. The method of claim 51, wherein the core comprises a first core and a second core on opposite sides of the winding portion, wherein the first core and the second core comprise planar surfaces facing a conductor loop formed by the winding and substantially parallel to the printed circuit board.

57. The method of claim 51, wherein the core comprises a first core opposite an open air portion, the first core having a base portion and three legs extending from the base portion, wherein a middle leg of the three legs extends through an opening defined by a conductor loop formed by the winding.

58. The method of claim 51, wherein the printed circuit board further comprises the controller and the power switching element located thereon.

59. The method of claim 51, wherein driving the power switching element by the controller to convert the received input power to output converted power comprises at least one selected from the group of:

Claims

1. A non-isolated power converter system, the system comprising:

A power converter including a power switching element;

The controller is or

One or more of the power switching elements.

10. A method of power conversion, the method comprising:

The controller is or

One or more of the power switching elements.

A core; and

one or more of the power switching elements of a power converter, or

42. A non-isolated power converter system, the system comprising:

A power converter including a power switching element;

The controller is or

One or more of the power switching elements.

47. A non-isolated power converter system as in claim 42, wherein said core includes first and second cores on opposite sides of said winding portion, wherein said first and second cores include planar surfaces facing said conductor loop and substantially parallel to said printed circuit board.

48. A non-isolated power converter system as defined in claim 42, wherein the core includes a first core opposite an open air portion, the first core having a base portion and three legs extending from the base portion, wherein a middle leg of the three legs extends through an opening defined by the conductor loop.

The controller is or

One or more of the power switching elements.

51. A method of power conversion, the method comprising:

56. The method of claim 51, wherein the core comprises a first core and a second core on opposite sides of the winding portion, wherein the first core and the second core comprise planar surfaces facing the conductor loop and substantially parallel to the printed circuit board.

57. The method of claim 51, wherein the core comprises a first core opposite an open air portion, the first core having a base portion and three legs extending from the base portion, wherein a middle leg of the three legs extends through an opening defined by the conductor loop.