Coupled filter inductors for interleaved power converters

Abstract

Aspects of the present disclosure include a filter comprising a first interleaved input, a second interleaved input, an output, a first transformer comprising a first primary winding having N1 turns and a first secondary winding having N2 turns, and a second transformer comprising a second primary winding having N3 turns and a second secondary winding having N4 turns, wherein the first primary winding and the second secondary winding are connected in series with the first interleaved input and output, and the first secondary winding and the second primary winding are connected in series with the second interleaved input and output.

Description

Technical Field

[0001] At least one example according to the present disclosure generally relates to a power device. Background Art

[0002] Power devices, such as uninterruptible power supplies (UPSs), can be used to supply power to one or more loads. Power devices can include power converters, such as DC / DC converters, AC / DC converters, and DC / AC converters. A DC / DC converter converts DC power at one voltage level to DC power at another voltage level. A DC / AC converter, or "inverter," converts DC power to AC power. An AC / DC converter, or "rectifier," converts AC power to DC power. Summary of the Invention

[0003] According to at least one aspect of the present disclosure, a filter is provided, comprising a first interleaved input, a second interleaved input, an output, a first transformer comprising a first primary winding having N1 turns and a first secondary winding having N2 turns, and a second transformer comprising a second primary winding having N3 turns and a second secondary winding having N4 turns, wherein the first primary winding and the second secondary winding are connected in series with the first interleaved input and the output, and the first secondary winding and the second primary winding are connected in series with the second interleaved input and the output.

[0004] In at least one example, the first primary winding and the first secondary winding are configured to generate in-phase magnetic fields that cancel each other. In some examples, the second primary winding and the second secondary winding are configured to generate in-phase magnetic fields that cancel each other. In various examples, the number of turns of N1 is within 20% of the number of turns of N4. In at least one example, the number of turns of N2 is within 20% of the number of turns of N3. In some examples, the number of turns of N2 is within 20% of the number of turns of N3. In at least one example, the same-name end of the first primary winding is coupled to the first interleaved input, and the opposite-name end of the first primary winding is coupled to the second secondary winding.

[0005] In some examples, the opposite-name terminal of the first secondary winding is coupled to the second interleaved input, and the same-name terminal of the first secondary winding is coupled to the second primary winding. In various examples, the opposite-name terminal of the second secondary winding is coupled to the opposite-name terminal of the first primary winding, and the same-name terminal of the second secondary winding is coupled to the output. In at least one example, the same-name terminal of the second primary winding is coupled to the first secondary winding, and the opposite-name terminal of the second primary winding is coupled to the output. In some examples, the opposite-name terminal of the first secondary winding is coupled to the second interleaved input, and the same-name terminal of the first secondary winding is coupled to the same-name terminal of the second primary winding.

[0006] In various examples, the first interleaved input is configured to couple to a first interleaved inverter, and the second interleaved input is configured to couple to a second interleaved inverter. In at least one example, a series connection of the first primary winding and the second secondary winding is coupled in parallel with a series combination of the first secondary winding and the second primary winding. In some examples, the first interleaved input is configured to receive a first signal, and the second interleaved input is configured to receive a second signal that is opposite in phase to the first signal. In various examples, a first magnetic field generated by the first primary winding in response to receiving the first signal is summed with a second magnetic field generated by the second primary winding in response to receiving the second signal.

[0007] In at least one example, in response to receiving a first signal with an anti-phase frequency and a second signal with an anti-phase frequency, the first transformer and the second transformer present an impedance to the first and second signals that is proportional to the square of the sum of N1 and N2. In some examples, the first interleaved input and the second interleaved input are configured to couple to a power converter having one or more switches configured to receive a pulse-width modulated switching signal, and the anti-phase frequency of the first and second signals is the frequency of the pulse-width modulated switching signal. In various examples, the first interleaved input is configured to receive the first signal, and the second interleaved input is configured to receive the second signal that is in phase with the first signal.

[0008] In at least one example, a first magnetic field generated by the first primary winding in response to receiving the first signal cancels a second magnetic field generated by the second primary winding in response to receiving the second signal. In some examples, in response to receiving the first signal and the second signal at the same frequency, the first transformer and the second transformer present an impedance to the first and second signals that is proportional to the square of the difference between N1 and N2. In various examples, the output is configured to couple to at least one load and provide output power to the at least one load, and wherein the in-phase frequencies of the first and second signals are the frequency of the output power.

[0009] According to at least one example of the present disclosure, a filtering system is provided, comprising a first interleaved input configured to be coupled to a first power converter, a second interleaved input configured to be coupled to a second power converter, an output, and a device for reducing a ripple current received from at least one of the first power converter or the second power converter.

[0010] According to at least one example of the present disclosure, a method for filtering a signal is provided, the method including receiving a first signal at a first interleaved input, providing the first signal to a first primary winding of a first transformer, the first transformer including a first primary winding having N1 turns and a first secondary winding having N2 turns, providing the first signal from the first primary winding to a second secondary winding of a second transformer including a second primary winding having N3 turns and a second secondary winding having N4 turns, providing the first signal from the second secondary winding to an output, receiving a second signal at a second interleaved input, providing the second signal to the first secondary winding, providing the second signal from the first secondary winding to the second primary winding, and providing the second signal from the second primary winding to the output. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Various aspects of at least one embodiment are discussed below with reference to the accompanying drawings, which are not intended to be drawn to scale. The accompanying drawings are included to provide illustration and a further understanding of the various aspects and embodiments and are incorporated into and constitute a part of the specification, but are not intended to be a definition of the limits of any particular embodiment. The accompanying drawings, together with the rest of the specification, serve to explain the principles and operation of the described and claimed aspects and embodiments. In the drawings, each identical or nearly identical component that is illustrated in various figures is represented by a like numeral. For clarity, not every component is labeled in every figure. In the drawings:

[0012] Figure 1 shows a block diagram of an uninterruptible power supply according to an example;

[0013] Figure 2 shows a block diagram of a power converter according to an example;

[0014] Figure 3 shows a schematic diagram of a filter according to an example;

[0015] Figure 4 shows a schematic diagram of a filter according to another example; and

[0016] Figure 5 A schematic diagram of a filter according to another example is shown. DETAILED DESCRIPTION

[0017] The examples of the methods and systems discussed herein are not limited in application to the details of construction and component arrangement set forth in the following description or shown in the accompanying drawings. These methods and systems can be implemented in other embodiments and can be practiced or implemented in various ways. The examples of specific implementations provided herein are for illustrative purposes only and are not intended to be limiting. In particular, the actions, components, elements, and features discussed in conjunction with any one or more examples are not intended to be excluded from similar roles in any other examples.

[0018] In addition, the wording and terminology used herein are for the purpose of description and should not be considered as restrictive. Any reference to the example, embodiment, assembly, element or action of the system and method mentioned in the singular herein may also cover the embodiment comprising a plurality, and any reference to any embodiment, assembly, element or action mentioned in the plural herein may also cover the embodiment comprising only the singular. Reference in the singular or plural form is not intended to limit the currently disclosed system or method, their assembly, action or element. " comprising ", " including ", " having ", " comprising ", " relating to " and its variants used herein are meant to include the project and its equivalent and additional project listed thereafter.

[0019] References to "or" may be interpreted as inclusive, such that any term described using "or" may refer to any of the described terms singly, more than one, and all of the described terms. Furthermore, in the event of inconsistencies in the usage of terms between this document and documents incorporated herein by reference, the usage of the term in the incorporated features supplements this document; for irreconcilable differences, the usage of the term in this document controls.

[0020] As described above, an electrical device such as an uninterruptible power supply (UPS) may include one or more power converters. A power converter converts power from one state to another. A power converter may include one or more switches configured to open or close in response to receiving a pulse width modulation (PWM) signal from a controller. The controller may use the PWM signal to control power conversion.

[0021] In some examples, it may be advantageous to interleave two or more power converter branches. Rather than implementing a single power converter to convert power, two or more converter branches may be connected in parallel. The PWM signals provided to the two or more converter branches may be time-shifted based on the number of converter branches. In one example, the PWM signals may be time-shifted by 360 / n degrees, where n is the number of interleaved power converter branches. For example, in the case of two interleaved converter branches, the controller may provide PWM signals to the two interleaved converter branches that are time-shifted by 180°.

[0022] Compared to implementing a single power converter, interleaving can advantageously reduce ripple current at the PWM frequency (and its odd harmonics). The total ripple current can be reduced, at least in part, because the ripple current in one converter leg can be in opposite phase to the ripple current in another converter leg at the PWM frequency (and its odd harmonics). As a result, the ripple current from each leg can cancel each other at the PWM frequency and its odd harmonics.

[0023] Reducing ripple current can reduce the size of filter components coupled to the power converter, such as capacitors and inductors. However, other factors may also affect the size of filter components. For example, reducing the size of one or more components may adversely affect the dynamic performance of the filter when a load step is present. Load steps may cause output voltage drops, which increase with decreasing component size. Therefore, component size can be selected based at least in part on dynamic performance constraints, which may be specified by regulators or consultants based on acceptable voltage drops caused by load steps.

[0024] The examples described herein provide filters configured to reduce ripple current while improving dynamic performance compared to existing solutions. In one example, the filter includes two or more interleaved coupled inductors connected to the output of a power converter. Interleaving can advantageously improve dynamic performance at least in part by presenting a short circuit to the load step current. In addition, the arrangement of the interleaved coupled inductors can advantageously avoid excessive core losses at least in part because both coupled inductors can filter out even and odd harmonics. Therefore, the filter provided herein improves filter performance relative to existing filters.

[0025] As mentioned above, filters are often used in power supply devices such as uninterruptible power supplies. Figure 1 is a block diagram of a UPS 100 according to one example. In another example, Figure 1 A block diagram of one of several power modules of a UPS may be shown. UPS 100 includes an input 102, an AC / DC converter 104, one or more DC buses 106, a DC / DC converter 108, an energy storage device interface 110, at least one controller 112 ("controller 112"), a DC / AC inverter 114, an output 116, memory and / or storage 118, and one or more communication interfaces 120 ("communication interfaces 120"), which may be communicatively coupled to one or more external systems 122 ("external systems 122").

[0026] Input 102 is coupled to an AC / DC converter 104 and an AC power source (not shown), such as an AC mains power source. AC / DC converter 104 is coupled to input 102 and one or more DC buses 106, and is communicatively coupled to a controller 112. One or more DC buses 106 are coupled to AC / DC converter 104, DC / DC converter 108, and DC / AC inverter 114, and are communicatively coupled to controller 112. DC / DC converter 108 is coupled to one or more DC buses 106 and an energy storage device interface 110, and is communicatively coupled to controller 112. Energy storage device interface 110 is coupled to DC / DC converter 108 and is configured to couple to at least one energy storage device 124 and / or another energy storage device.

[0027] In some examples, energy storage device 124 is external to UPS 100 and coupled to UPS 100 via energy storage device interface 110. In various examples, UPS 100 may include one or more energy storage devices, which may include energy storage device 124. Energy storage device 124 may include one or more batteries, capacitors, flywheels, or other energy storage devices.

[0028] The DC / AC inverter 114 is coupled to one or more DC buses 106 and an output 116, and is communicatively coupled to a controller 112. The output 116 is coupled to the DC / AC inverter 114 and an external load (not shown). The controller 112 is communicatively coupled to the AC / DC converter 104, the one or more DC buses 106, the DC / DC converter 108, the energy storage device interface 110, the DC / AC inverter 114, a memory and / or storage 118, and a communication interface 120.

[0029] The input 102 is configured to couple to an AC mains power source and receive input AC power having an input voltage level. The UPS 100 is configured to operate in different operating modes based on the input voltage of the AC power provided to the input 102. The controller 112 may determine the operating mode of the UPS 100 based on whether the input voltage of the AC power is acceptable. The controller 112 may include or be coupled to one or more sensors configured to sense input voltage parameters. For example, the controller 112 may include or be coupled to one or more sensors configured to sense the voltage level of the AC power received at the input 102.

[0030] When the AC power provided to input 102 is acceptable (e.g., by having parameters that meet specified values, such as an input voltage value, e.g., by falling within a range of acceptable input voltage values), controller 112 controls the components of UPS 100 to operate in a normal operating mode. In normal operating mode, AC power received at input 102 is provided to AC / DC converter 104. AC / DC converter 104 converts the AC power to DC power and provides the DC power to one or more DC buses 106. One or more DC buses 106 distribute the DC power to DC / DC converter 108 and DC / AC inverter 114. DC / DC converter 108 converts the received DC power and provides the converted DC power to energy storage device interface 110. Energy storage device interface 110 receives the converted DC power and provides the converted DC power to energy storage device 124 to charge energy storage device 124. DC / AC inverter 114 receives DC power from one or more DC buses 106, converts the DC power to conditioned AC power, and provides the conditioned AC power to output 116 for delivery to a load.

[0031] When the AC power provided to input 102 from the AC main power source is unacceptable (e.g., by having parameters that do not meet specified values, such as an input voltage value, such as by falling outside a range of acceptable input voltage values), controller 112 controls the components of UPS 100 to operate in a backup operating mode. In the backup operating mode, DC power is released from energy storage device 124 to energy storage device interface 110, which provides the released DC power to DC / DC converter 108. DC / DC converter 108 converts the received DC power and distributes the DC power among one or more DC buses 106. For example, DC / DC converter 108 can evenly distribute the power among one or more DC buses 106. One or more DC buses 106 provide the received power to DC / AC inverter 114. DC / AC inverter 114 receives DC power from one or more DC buses 106, converts the DC power into conditioned AC power, and provides the conditioned AC power to output 116.

[0032] The controller 112 may store information in the memory and / or storage 118 and / or retrieve information from the memory and / or storage 118. For example, the controller 112 may store information indicating a sensed parameter (e.g., an input voltage value of the AC power received at the input 102) in the memory and / or storage 118. The controller 112 may also receive information from the communication interface 120 or provide information to the communication interface 120. The communication interface 120 may include one or more communication interfaces, including, for example, a user interface (such as a display screen, a touch screen, a keyboard, a mouse, a trackpad, a dial, a button, a switch, a slider, a light emitting component such as a light emitting diode, a sound emitting component such as a speaker, a buzzer, etc., configured to output sounds within and / or outside the frequency range audible to humans, etc.), a wired communication interface (such as a wired port), a wireless communication interface (such as an antenna), etc., configured to exchange information with one or more systems, such as the external system 122 or other entities, such as humans. The external system 122 may include any device, component, module, etc. external to the UPS 100, such as a server, database, laptop computer, desktop computer, tablet computer, smart phone, central controller or data aggregation system, other UPS, etc.

[0033] In some examples, UPS 100 may be a multi-phase UPS, such as a three-phase UPS. For example, input 102 may include multiple inputs, each configured to receive a corresponding phase line (and, in some examples, the multiple inputs may include a return input). Thus, although Figure 1 The examples may be described with respect to a single connection and / or single phase operation, but it should be understood that multi-phase operation is Figure 1 and the entire public domain.

[0034] As described above, the power converters may include and / or be coupled to filters. For example, one or more of converters 104, 108, 114 may include and / or be coupled to one or more filters. Converters 104, 108, 114 may include one or more filtering components to, for example, reduce ripple current. In some examples, converters 104, 108, 114 may each be implemented with multiple interleaved converter branches in a single-phase or multi-phase system. For example, UPS 100 may be a three-phase UPS, and one or more converters 104, 108, 114 may include two or more interleaved power conversion branches. For purposes of explanation, an example is provided in which one or more converters 104, 108, 114 include two or more interleaved power conversion branches.

[0035] Figure 2A block diagram of a power converter 200 according to an example is shown. In some examples, power converter 200 can be an example of any power converter 104, 108, 114. Power converter 200 includes an input 202, an output 204, a first branch 206, a second branch 208, and in some examples, an optional output filter 210. First branch 206 includes a first interleaved power converter 212a and one or more filtering components 214a ("first filtering component 214a"). Second branch 208 includes a second interleaved power converter 212b and one or more filtering components 214b ("second filtering component 214b"). First filtering component 214a and second filtering component 214b together form filter 216. It should be understood that power converter 200 can include any number of interleaved branches (including three or more branches), and only two branches are shown for illustrative purposes.

[0036] Input 202 is coupled to branches 206 and 208 and is configured to be coupled to a power supply and / or a power sink. Branches 206 and 208 are coupled in parallel with each other, and each branch is coupled to input 202 at a respective first connection and to an optional output filter 210 at a respective second connection. In examples where optional output filter 210 is not included, branches 206 and 208 can be coupled directly to output 204 at respective second connections. In examples where filter 210 is included, optional output filter 210 is coupled to branches 206 and 208 at a first connection and to output 204 at a second connection. Output 204 is coupled to optional output filter 210 and is configured to be coupled to a power sink and / or a power supply. In examples where optional output filter 210 is not included, output 204 can be coupled to filter 216 in place of optional output filter 210.

[0037] In each branch 206, 208, a corresponding interleaved power converter 212 (i.e., either one of power converters 212a, 212b) is coupled at a first connection to a corresponding filtering component 214 (i.e., a corresponding one of filtering components 214a, 214b) and at a second connection to input 202. Each filtering component 214 is coupled at a first connection to a corresponding one of interleaved power converters 212 and at a second connection to optional output filter 210. In examples where optional output filter 210 is not included, each filtering component 214 can be coupled directly to output 204 at a second connection.

[0038] Although the filter components 214 are shown as separate components for purposes of explanation, in some examples, the filter components 214 can be coupled to each other. For example, a first filter component 214a can include at least one first inductor, and a second filter component 214b can include at least one second inductor magnetically coupled to the at least one first inductor, such that the filter components 214 collectively constitute a filter 216. In other examples, the filter components 214 can operate independently of each other.

[0039] As described above, the power converter 200 can be implemented as any of the power converters 104, 108, 114. For example, where the power converter 200 is an implementation of the AC / DC converter 104, the input 202 can be coupled to the input 102, and the output 204 can be coupled to the DC bus 106. It should be understood that the term "input" does not imply any limitation. One or more of the power converters 104, 108, 114 can be bidirectional. For example, the DC / DC converter 108 can draw power from the energy storage device 124 via the energy storage device interface 110 at one point in time (e.g., during a backup operating mode in which utility power is unavailable, as described above), and can provide power to the energy storage device 124 via the energy storage device interface 110 at another point in time (e.g., during a normal operating mode in which utility power is available and used to charge the energy storage device 124, as described above).

[0040] Thus, although power converter 200 may be described as providing power in a certain direction (e.g., drawing power at input 202 and providing power at output 204), it should be understood that power converter 200 or other power converters within the scope of the present disclosure may be bidirectional. For example, where power converter 200 is an implementation of DC / DC converter 108, input 202 may be coupled to DC bus 106, and output 204 may be coupled to energy storage device interface 110. However, because DC / DC converter 108 may be bidirectional in some examples, DC / DC converter 108 may also provide power to DC bus 106 at input 202 and receive power from energy storage device interface 110 at output 204. Thus, it should be understood that a component referred to as an "input" may provide and / or receive power, and a component referred to as an "output" may receive and / or provide power.

[0041] Each interleaved power converter 212 may include one or more switches. The one or more switches may be modulated to convert power. The controller 112 may be coupled to each interleaved power converter 212 to control the one or more switches, thereby controlling power conversion. For example, the controller 112 may send one or more PWM signals to the one or more switches to control the corresponding switching state of each of the one or more switches.

[0042] The controller 112 can send a time-shifted PWM signal to the interleaved power converters 212. As will be appreciated by one of ordinary skill in the art, the time-shifted PWM signals can be identical, except that the signals are shifted in time relative to each other. In various examples, the signals can be shifted by 360 / n degrees, where n is the number of interleaved power converters. For example, if the interleaved power converters 212 include three interleaved power converters, the controller 112 can provide a PWM signal that is time-shifted by 120° to the interleaved power converters 212. Similarly, if the interleaved power converters 212 include two interleaved power converters, the controller 112 can provide a PWM signal that is time-shifted by 180° to the interleaved power converters 212. An example of a system with two interleaved power converters 212 is provided below.

[0043] Figure 3 A schematic diagram of a filter 300 according to an example is shown. Filter 300 may illustrate an example of filter 216. Filter 300 includes a first inductor 302 and a second inductor 304. First inductor 302 may illustrate an example of first filtering component 214a. Second inductor 304 may illustrate an example of second filtering component 214b. In some examples, inductors 302 and 304 are magnetically coupled to each other. In other examples, inductors 302 and 304 are not magnetically coupled to each other.

[0044] First inductor 302 is configured to be coupled to a first power converter at a first connection (e.g., to first interleaved power converter 212a) and to be coupled to an output at a second connection (e.g., directly to output 204 or, in some examples, via optional output filter 210). Second inductor 304 is configured to be coupled to a second power converter at a first connection (e.g., to second interleaved power converter 212b) and to be coupled to an output at a second connection (e.g., directly to output 204 or, in some examples, via optional output filter 210).

[0045] Filter 300 can filter a signal received from an interleaved power converter to provide a filtered output signal to an output. For example, where filter 300 is an example of filter 216, filter 300 can filter a signal received from interleaved power converter 212 to provide a filtered output signal to output 204. Filter 300 can reduce ripple current and smooth the output signal (e.g., by smoothing a relative square wave into a relative sine wave). However, the size of inductors 302, 304 may be relatively large to achieve the desired ripple current reduction, which may adversely affect the dynamic response of filter 300.

[0046] Figure 4 A schematic diagram of a filter 400 according to another example is shown. Filter 400 can illustrate an example of filter 216. Filter 400 includes a first inductor 402, a second inductor 404, and a coupled inductor 406 having a first portion 408 and a second portion 410. First inductor 402 and first portion 408 of coupled inductor 406 can collectively represent an example of first filter component 214a. Second inductor 404 and second portion 410 of coupled inductor 406 can collectively represent an example of second filter component 214b.

[0047] First inductor 402 is coupled to first portion 408 of coupled inductor 406 at a first connection and is configured to be coupled to a first power converter (e.g., first interleaved power converter 212a) at a second connection. In some examples, first inductor 402 is magnetically coupled to second inductor 404. Second inductor 404 is coupled to second portion 410 of coupled inductor 406 at a first connection and is configured to be coupled to a second power converter (e.g., second interleaved power converter 212b) at a second connection. In some examples, second inductor 404 is magnetically coupled to first inductor 402.

[0048] A first portion 408 of coupled inductor 406 is coupled to first inductor 402 at a like-name terminal and to an output at an opposite-name terminal (e.g., output 204, either directly or, in some examples, via optional output filter 210). In some examples, first portion 408 of coupled inductor 406 is magnetically coupled to second portion 410 of coupled inductor 406. Second portion 410 of coupled inductor 406 is coupled to second inductor 404 at an opposite-name terminal and to an output at a like-name terminal (e.g., output 204, either directly or, in some examples, via optional output filter 210). In some examples, second portion 410 of coupled inductor 406 is magnetically coupled to first portion 408 of coupled inductor 406.

[0049] Filter 400 can filter the signal received from interleaved power converter 212 to provide a filtered output signal to output 204. First inductor 402 and second inductor 404 of filter 400 can operate in a similar manner to first inductor 302 and second inductor 304 of filter 300. Coupled inductor 406 can act as a transformer, where the current in first portion 408 of coupled inductor 406 generates a magnetic field that cancels the magnetic field generated by the opposite-phase current in second portion 410 of coupled inductor 408. Thus, filter 400 can present a relatively large impedance to the opposite-phase current, such as ripple current at the PWM frequency.

[0050] However, filter 400 can present a relatively small impedance to currents in phase with the load current, at least in part because the in-phase currents in coupled inductor 406 generate mutually canceling magnetic fields, thereby approximately acting as a short circuit for the in-phase currents. Thus, while inductors 402 and 404 can present a relatively large impedance to in-phase currents, coupled inductor 406 can present a relatively large impedance to out-of-phase currents.

[0051] In various examples, the size of inductors 402, 404 can be smaller than the size of inductors 302, 304, at least in part because ripple current at the PWM frequency and its odd harmonics is minimized by the high impedance of coupled inductor 406. Furthermore, the dynamic response of filter 400 can be improved relative to filter 300, at least in part because load steps present currents to inductors 402, 404 at substantially similar times, thereby presenting in-phase currents to the branches of filter 400.

[0052] As described above, the inductors 402, 404 of the filter 400 can be much smaller than the inductors 302, 304 of the filter 300. However, the coupled inductor 406 can experience relatively high losses from the harmonic voltages of the PWM frequency, at least in part because, as described above, the coupled inductor 406 can be primarily responsible for absorbing the harmonic voltages in the filter 400. Although low-loss magnetic core materials (e.g., amorphous cores, ferrite cores, etc.) can be achieved, these materials can be expensive, bulky, and / or introduce challenging design requirements. In addition, accurate current sensing and control instrumentation can be implemented to avoid current imbalance and core saturation, thereby introducing additional cost and complexity.

[0053] Figure 5Schematic diagram of a filter 500 according to another example is shown. Filter 500 can illustrate an example of filter 216. Filter 500 includes a first transformer 502 and a second transformer 504. First transformer 502 includes a first primary winding 506 and a first secondary winding 508. Second transformer 504 includes a second primary winding 510 and a second secondary winding 512. First primary winding 506 and second secondary winding 512 can collectively represent an example of first filter component 214a. First secondary winding 508 and second primary winding 510 can collectively represent an example of second filter component 214b. Filter 500 also includes a first interleaved input 514, a second interleaved input 516, and an output 518.

[0054] The first primary winding 506 is coupled to the first interleaved input 514 at the same terminal and to the second secondary winding 512 at the opposite terminal. In some examples, the first primary winding 506 is magnetically coupled to the first secondary winding 508. The first secondary winding 508 is coupled to the second interleaved input 516 at the opposite terminal and to the second primary winding 510 at the same terminal. In some examples, the first secondary winding 508 is magnetically coupled to the first primary winding 506.

[0055] The second primary winding 510 is coupled to the first secondary winding 508 at a like-name terminal and to the output 518 at an opposite-name terminal. In some examples, the second primary winding 510 is magnetically coupled to the second secondary winding 512. The second secondary winding 512 is coupled to the first primary winding 506 at an opposite-name terminal and to the output 518 at a like-name terminal. In some examples, the second secondary winding 512 is magnetically coupled to the second primary winding 510.

[0056] A first interleaved input 514 is coupled to the first primary winding 506 and is configured to be coupled to a power converter (e.g., the first interleaved power converter 212a). A second interleaved input 516 is coupled to the first secondary winding 508 and is configured to be coupled to a power converter (e.g., the second interleaved power converter 212b). An output 518 is coupled to the second primary winding 510 and the second secondary winding 512 and is configured to be coupled to a power converter output (e.g., directly to the output 204 or, in some examples, via the optional output filter 210).

[0057] A first signal can be received at a first interleaved input 514 and provided to the first primary winding 506. The first signal can generate a magnetic field in the first primary winding 506, which can induce a current in the first secondary winding 508. The first primary winding 506 can provide the first signal to the second secondary winding 512. The first signal can generate a magnetic field in the second secondary winding 512, which can induce a current in the second primary winding 510. The second secondary winding 512 can provide the first signal to the output 518.

[0058] A second signal can be received at the second interleaved input 516 and provided to the first secondary winding 508. The second signal can generate a magnetic field in the first secondary winding 508, which can induce a current in the first primary winding 506. The first secondary winding 508 can provide a second signal to the second primary winding 510. The second signal can generate a magnetic field in the second primary winding 510, which can induce a current in the second secondary winding 512. The second primary winding 510 can provide a second signal to the output 518.

[0059] In various examples, the impedance presented by transformers 502, 504 to the first and / or second signals depends at least in part on the number of windings of transformers 502, 504. First primary winding 506 has N1 windings, first secondary winding 508 has N2 windings, second primary winding 510 has N4 windings, and second secondary winding 512 has N3 windings. In one example, N1 is approximately equal to N4, and N2 is approximately equal to N3. The impedance presented by transformers 502, 504 may also depend at least in part on the frequency of the signal received by transformers 502, 504.

[0060] Due to the interleaving of the power converters, the signals received at the PWM frequency arrive at the filter 500 in opposite phase. The magnetic fields generated by the opposite currents in the transformers 502, 504 can add to each other. The inductance presented to the signal by the first transformer 502 can be equal to (N1 + N2) 2 *A L , where A L is the specific inductance of a single turn of the magnetic core used for windings 506, 508. In some examples, each turn of windings 506, 508 may have the same specific inductance A. L In other examples, the turns may have different specific inductances (e.g., due to manufacturing variations), and A L The inductance presented to the signal by the second transformer 504 may be equal to (N3 + N4) 2 *A L , where A Lis the specific inductance of a single turn of the magnetic core used for windings 510, 512. In some examples, each turn of windings 510, 512 may have the same specific inductance A. L In other examples, the turns may have different specific inductances (e.g., due to manufacturing variations), and A L It can be expressed as the average specific inductance of a turn.

[0061] Signals received at the load current frequency or other non-interleaved frequencies may arrive at the filter 500 in phase with each other. The magnetic fields generated by the in-phase currents in the transformers 502, 504 may oppose each other. The inductance presented to the signal by the first transformer 502 may be equal to (N1-N2) 2 *A L , where AL is the specific inductance of a single turn of the magnetic core used for windings 506, 508. In some examples, each turn of windings 506, 508 may have the same specific inductance A. L In other examples, the turns may have different specific inductances (e.g., due to manufacturing variations), and A L The inductance presented to the signal by the second transformer 504 may be equal to (N4 – N3) 2 *A L , where A L is the specific inductance of a single turn of the magnetic core used for windings 510, 512. In some examples, each turn of windings 510, 512 may have the same specific inductance A. L In other examples, the turns may have different specific inductances (e.g., due to manufacturing variations), and A L It can be expressed as the average specific inductance of a turn.

[0062] Thus, transformers 502, 504 can present different inductances (and therefore different impedances) to in-phase currents (e.g., signals at the load frequency), as opposed to out-of-phase currents (e.g., signals at the PWM frequency). The effective number of turns experienced by an in-phase current, such as the load current, can be proportional to the difference (e.g., the squared difference) between the number of primary and secondary windings of each transformer 502, 504. The effective number of turns experienced by an out-of-phase current (e.g., a signal at the PWM frequency) can be proportional to the sum (e.g., the squared sum) of the number of primary and secondary windings of each transformer 502, 504. The magnetic field generated by the in-phase current can be reduced by the same factor as the effective inductance is reduced (relative to, for example, other filters having the same number of turns but a different arrangement, such as filter 300), which can allow a higher core permeability material to be used as the core material of transformers 502, 504 without substantially changing the overall relative core saturation.

[0063] Thus, the examples provided herein improve power converter filtering at least in part by reducing ripple current while improving dynamic response to load step currents. In various examples, transformers 502, 504 can be designed as substantially similar or identical components, thereby reducing the complexity of filter 500. The number of windings of transformers 502, 504 can be selected based on the design requirements of filter 500, and in various examples, transformers 502, 504 can include low-cost and / or low-complexity core materials. Thus, filter 500 can be reduced in size, cost, and / or complexity compared to some existing solutions.

[0064] As described above, N1, N2, N3, and N4 can be selected based on one or more design requirements. In some examples, N1 can be configured to be within a specific number of turns of N4. For example, N1 can be configured to be within 12 turns of N4. Continuing with this example, if N1 has 35 turns, then N4 can have 23 to 47 turns. In other examples, N1 can be configured to have a number of turns that is within a certain percentage of N4's number of turns. For example, N1 can be configured to have a number of turns that is within 20% of N4's number of turns. Continuing with this example, if N1 has 35 turns, then N4 can have 28 to 42 turns, i.e., within 7 turns of 35.

[0065] Similarly, in various examples, N2 can be configured to be within a specific number of turns of N3. For example, N2 can be configured to be within two turns of N3. Continuing with this example, if N2 has seven turns, then N3 may have five to nine turns. In other examples, N2 can be configured to have a number of turns that is within a certain percentage of N3's number of turns. For example, N2 can be configured to have a number of turns that is within 20% of N3's number of turns. Continuing with this example, if N2 has seven turns, then N3 may have six to eight turns, i.e., within 1.4 of seven turns.

[0066] In one example, the ratio of N1:N2 and N4:N3 is between 4:1 and 6:1. In one example, N1 and N4 are each approximately 35, and N2 and N3 are each approximately 7. Therefore, in one example, N1 equals N4, N2 equals N3, and N1:N2 is 35:7.

[0067] As described above, the optional output filter 210 may include one or more filtering components. In one example, the optional output filter 210 includes one or more capacitors. For example, the optional output filter 210 may include one or more capacitors that present a 40 μF capacitance to the signal originating from each of the second primary winding 510 and the second secondary winding 512. In some examples, the capacitance may depend in part on N1, N2, N3, N4, and A. L In some cases, A L It can be about 138nH.

[0068] In various examples, where power converter 200 is bidirectional, components of power converter 200 may be added, removed, and / or rearranged. For example, power converter 200 may include additional filters between interleaved power converter 212 and input 202, and / or may include one or more bypass switches to route signals as needed or desired.

[0069] Various controllers, such as controller 112, can perform the various operations described above. For example, as described above, controller 112 can control the switching operations of converters 104, 108, and 114, as well as other operations. Using data stored in associated memory and / or storage devices, controller 112 can execute one or more instructions stored on one or more non-transitory computer-readable media that controller 112 may include and / or be coupled to, which can generate manipulated data. In some examples, controller 112 may include one or more processors or other types of controllers. In one example, controller 112 is or includes at least one processor. In another example, in addition to or in lieu of a general-purpose processor, controller 112 uses an application-specific integrated circuit (ASIC) customized to perform the specific operations to perform at least a portion of the operations described above. As these examples illustrate, many specific combinations of hardware and software may be used to perform the operations described herein, according to examples of the present disclosure, and the present disclosure is not limited to any specific combination of hardware and software components. Examples of the present disclosure may include computer program products configured to perform the methods, processes, and / or operations described above. The computer program product may be or include one or more controllers and / or processors configured to execute instructions to perform the above-described methods, processes, and / or operations.

[0070] Having thus described several aspects of at least one embodiment, it should be understood that various alterations, modifications, and improvements will readily occur to those skilled in the art. Such alterations, modifications, and improvements are intended to be a part of this disclosure and are within the spirit and scope of this disclosure. Therefore, the foregoing description and accompanying drawings are merely illustrative.

Claims

1. A filter comprising: a first interleaved input configured to receive a first signal; a second interleaved input configured to receive a second signal in phase with the first signal; Output; A first transformer including a first primary winding having N1 turns and a first secondary winding having N2 turns; and The second transformer includes a second primary winding having N4 turns and a second secondary winding having N3 turns, wherein A first primary winding and a second secondary winding are connected in series with the first interleaved input and output, and The first secondary winding and the second primary winding are connected in series with the second interleaved input and output.

2. The filter according to claim 1, wherein The first primary winding and the first secondary winding are configured to generate in-phase magnetic fields that cancel each other.

3. The filter according to claim 1, wherein The second primary winding and the second secondary winding are configured to generate in-phase magnetic fields that cancel each other.

4. The filter according to claim 1, wherein The number of turns of N1 is within 20% of the number of turns of N4.

5. The filter according to claim 4, wherein The number of turns of N2 is within 20% of the number of turns of N3.

6. The filter according to claim 1, wherein The number of turns of N2 is within 20% of the number of turns of N3.

7. The filter according to claim 1, wherein A like-name terminal of the first primary winding is coupled to the first interleaved input, and an opposite-name terminal of the first primary winding is coupled to the second secondary winding.

8. The filter according to claim 7, wherein The opposite-signal terminal of the first secondary winding is coupled to the second interleaved input, and the same-signal terminal of the first secondary winding is coupled to the second primary winding.

9. The filter according to claim 7, wherein The opposite-name terminal of the second secondary winding is coupled to the opposite-name terminal of the first primary winding, and the same-name terminal of the second secondary winding is coupled to the output.

10. The filter according to claim 9, wherein The same-name terminal of the second primary winding is coupled to the first secondary winding, and the opposite-name terminal of the second primary winding is coupled to the output.

11. The filter according to claim 10, wherein The opposite-name terminal of the first secondary winding is coupled to the second interleaved input, and the same-name terminal of the first secondary winding is coupled to the same-name terminal of the second primary winding.

12. The filter according to claim 1, wherein The first interleaving input is configured to be coupled to a first interleaving inverter, and wherein the second interleaving input is configured to be coupled to a second interleaving inverter.

13. The filter according to claim 1, wherein The series connection of the first primary winding and the second secondary winding is coupled in parallel with the series combination of the first secondary winding and the second primary winding.

14. The filter according to claim 1, wherein A first magnetic field generated by the first primary winding in response to receiving the first signal and a second magnetic field generated by the second primary winding in response to receiving the second signal cancel each other out.

15. The filter according to claim 1, wherein In response to receiving a first signal at an in-phase frequency and a second signal at an in-phase frequency, the first transformer and the second transformer present an impedance to the first signal and the second signal that is proportional to the square of the difference between N1 and N2.

16. The filter according to claim 15, wherein The output is configured to couple to at least one load and provide output power to the at least one load, and wherein the in-phase frequency of the first signal and the second signal is the frequency of the output power.

17. A method for filtering a signal, the method comprising: receiving a first signal at a first interleave input; providing a first signal to a first primary winding of a first transformer, the first transformer including a first primary winding having N1 turns and a first secondary winding having N2 turns; providing a first signal from the first primary winding to a second secondary winding of a second transformer, the second transformer including a second primary winding having N4 turns and a second secondary winding having N3 turns; providing a first signal from the second secondary winding to an output; receiving a second signal in phase with the first signal at a second interleaved input; providing a second signal to the first secondary winding; providing a second signal from the first secondary winding to the second primary winding; and A second signal from the second primary winding is provided to the output.

18. A filter comprising: a first interleaved input configured to receive a first signal; a second interleaved input configured to receive a second signal having an opposite phase to the first signal; Output; A first transformer including a first primary winding having N1 turns and a first secondary winding having N2 turns; and The second transformer includes a second primary winding having N4 turns and a second secondary winding having N3 turns, wherein A first primary winding and a second secondary winding are connected in series with the first interleaved input and output, and The first secondary winding and the second primary winding are connected in series with the second interleaved input and output, and In response to receiving a first signal at an anti-phase frequency and a second signal at an anti-phase frequency, the first transformer and the second transformer present an impedance proportional to the square of the sum of N1 and N2 to the first signal and the second signal.

19. The filter of claim 18, wherein a first magnetic field generated by the first primary winding in response to receiving the first signal is added to a second magnetic field generated by the second primary winding in response to receiving the second signal.

20. The filter of claim 18, wherein the first interleaved input and the second interleaved input are configured to be coupled to a power converter having one or more switches configured to receive a pulse width modulated switching signal, and wherein the anti-phase frequency of the first signal and the second signal is the frequency of the pulse width modulated switching signal.

21. A filter comprising: First interleaved input; Second interleaved input; Output; A first transformer including a first primary winding having N1 turns and a first secondary winding having N2 turns; and The second transformer includes a second primary winding having N4 turns and a second secondary winding having N3 turns, wherein a first primary winding and a second secondary winding connected in series with the first interleaved input and output, a first secondary winding and a second primary winding connected in series with a second interleaved input and output, The same-name end of the first primary winding is coupled to the first interleaved input, The opposite end of the first primary winding is coupled to the second secondary winding, The opposite-signal end of the first secondary winding is coupled to the second interleaved input, and The like-named end of the first secondary winding is coupled to the second primary winding.

22. The filter of claim 21, wherein a like-name terminal of the second primary winding is coupled to the first secondary winding, and an opposite-name terminal of the second primary winding is coupled to the output.

23. A filter comprising: First interleaved input; Second interleaved input; Output; A first transformer including a first primary winding having N1 turns and a first secondary winding having N2 turns; and The second transformer includes a second primary winding having N4 turns and a second secondary winding having N3 turns, wherein a first primary winding and a second secondary winding connected in series with the first interleaved input and output, a first secondary winding and a second primary winding connected in series with a second interleaved input and output, The same-name end of the first primary winding is coupled to the first interleaved input, The opposite end of the first primary winding is coupled to the second secondary winding, The opposite-signal end of the second secondary winding is coupled to the opposite-signal end of the first primary winding, and The like-named end of the second secondary winding is coupled to the output.

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