Interleaved control of dc-dc midpoint topology

Abstract

This application discloses DCDC midpoint topology interleaving control. A DC-DC converter that converts an input DC voltage to an output DC voltage includes a first switching network, a first transformer component, a second transformer, a first secondary side rectifier circuit, and a second secondary side rectifier circuit. The first secondary side rectifier circuit receives a first secondary side AC voltage and outputs a first temporal portion of the output DC voltage during a first portion of a duty cycle. The second secondary side rectifier circuit receives a second secondary side AC voltage and outputs a second temporal portion of the output DC voltage during a second portion of the duty cycle.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims the benefit of U.S. Provisional Application Serial No. 63 / 126,601, filed on December 17, 2020, the disclosure of which is hereby incorporated by reference in its entirety. Technical Field

[0003] In at least one aspect, a method and apparatus are provided for DC-to-DC conversion in an electric or hybrid electric vehicle.

[0004] Overview

[0005] In at least one aspect, a DC-DC converter is provided for converting an input DC voltage into an output DC voltage. The DC-DC converter includes a primary-side switching network, a first transformer component, a second transformer, a first secondary-side switching network, and a second secondary-side switching network. The primary-side switching network receives an input DC voltage and outputs a primary-side AC voltage. The first transformer component includes a first plurality of primary windings and a first plurality of secondary windings. The first transformer component receives a primary-side AC voltage and outputs a first secondary-side AC voltage. The second transformer component includes a second plurality of primary windings and a second plurality of secondary windings. The first plurality of primary windings are connected in series with the second plurality of primary windings. The second transformer component receives a primary-side AC voltage and outputs a second secondary-side AC voltage. The first secondary-side switching network receives the first secondary-side AC voltage, and the second secondary-side switching network receives the second secondary-side AC voltage. Characteristically, the outputs from the first plurality of secondary windings and the second plurality of secondary windings are combined to form the output DC voltage.

[0006] In another aspect, in the DC-DC converter, there is a first phase difference between the first plurality of secondary windings and the first plurality of primary windings, and there is a second phase difference between the second plurality of secondary windings and the second plurality of primary windings.

[0007] Advantageously, the DC-DC converter improves performance while providing high flexibility. The design also offers cost reduction and time to market. The DC-DC converter is particularly well-suited for fault-tolerant applications. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] For a further understanding of the nature, objects and advantages of the present disclosure, reference should be made to the following detailed description read in conjunction with the following drawings, in which like reference numerals represent like elements, and wherein:

[0009] Figure 1A is a schematic diagram of a DC-DC converter having two transformers with primary windings configured in a series configuration.

[0010] Figure 1B is a schematic diagram of a DC-DC converter having three transformers with primary windings arranged in a series configuration.

[0011] Figure 1C yes Figure 1A and Figure 1B Schematic diagram of the transformer used in the system.

[0012] Figure 2A is the output current of a full-bridge stage during standard operation and the contribution of each of the three secondary windings.

[0013] Figure 2B is the output current of one full-bridge stage and the contribution of each of the three secondary windings during the new phase-shifted operation. Detailed description

[0014] Reference will now be made in detail to the presently preferred embodiments and methods of the present invention, which constitute the best modes of practicing the present invention presently known to the inventors. The drawings are not necessarily drawn to scale. However, it should be understood that the disclosed embodiments are merely examples of the present invention that may be implemented in various forms and alternative forms. Therefore, the specific details disclosed herein should not be construed as limiting, but merely as a representative basis for any aspect of the present invention and / or as a representative basis for teaching those skilled in the art to utilize the present invention in various ways.

[0015] It should also be understood that the present invention is not limited to the specific embodiments and methods described below, as specific components and / or conditions may vary. In addition, the terminology used herein is used only for the purpose of describing specific embodiments of the present invention and is not intended to be limiting in any way.

[0016] It must also be noted that, as used in the specification and the appended claims, the singular forms "a," "an," and "the" include plural referents unless the context clearly dictates otherwise. For example, a component mentioned in the singular is intended to include a plurality of components.

[0017] The term "comprising" is synonymous with "including," "having," "containing," or "characterized by." These terms are inclusive and open-ended and do not exclude additional, undescribed elements or method steps.

[0018] The phrase "consisting of" excludes any elements, steps, or ingredients not specified in the claim. When the phrase appears in a clause in the body of a claim rather than immediately following the preamble, it limits only the elements recited in that clause; other elements are not excluded from the claim as a whole.

[0019] The phrase "consisting essentially of" limits the scope of a claim to the specified materials or steps, plus those that do not materially affect the basic and novel characteristics of the claimed subject matter.

[0020] With respect to the terms "comprising," "consisting of," and "consisting essentially of," to the extent that one of these three terms is used herein, the presently disclosed and claimed subject matter may include the use of either of the other two terms.

[0021] It should also be appreciated that integer ranges include all intermediate integers. For example, the integer range 1-10 includes 1, 2, 3, 4, 5, 6, 7, 8, 9, and 10. Similarly, the range 1 to 100 includes 1, 2, 3, 4, ..., 97, 98, 99, 100. Similarly, when any range is required, the difference between the upper and lower limits divided by 10 as the intermediate digit of increment can be considered as an optional upper or lower limit. For example, if the range is 1.1 to 2.1, the following digits 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, and 2.0 can be selected as the lower or upper limit.

[0022] The term "connected to" means that the electrical components being connected to are in electrical communication. In one refinement, "connected to" means that the electrical components being connected to are directly connected to each other with wires. In another refinement, "connected to" means that the electrical components are communicating wirelessly or through a combination of wired and wirelessly connected components. In another refinement, "connected to" means that one or more additional electrical components are interposed between the electrical components being connected to, and that the electrical signal from the originating component is processed (e.g., filtered, amplified, modulated, rectified, attenuated, summed, subtracted, etc.) before being received by the components connected to it.

[0023] The term "electrical communication" means the transmission of an electrical signal, directly or indirectly, from an originating electronic device to a receiving electrical device. Indirect electrical communication may involve processing of the electrical signal, including but not limited to filtering of the signal, amplification of the signal, rectification of the signal, modulation of the signal, attenuation of the signal, addition of a signal to another signal, subtraction of a signal from another signal, subtraction of another signal from a signal, and the like. Electrical communication may be accomplished using wired components, wirelessly connected components, or a combination thereof.

[0024] The term "electrical signal" refers to an electrical output from or input to an electronic device. An electrical signal is characterized by voltage and / or current. An electrical signal can be a fixed signal or it can vary over time.

[0025] The term "DC signal" or "DC voltage" refers to an electrical signal or voltage having a voltage value that is always greater than 0 volts.

[0026] The term "AC signal" or "AC voltage" refers to an electrical signal or voltage having a voltage that varies between positive and negative voltages and crosses 0 volts.

[0027] The term "electronic component" refers to any physical entity in an electronic device or system that affects the state of electrons, the flow of electrons, or the electric fields associated with electrons. Examples of electronic components include, but are not limited to, capacitors, inductors, resistors, thyristors, diodes, transistors, and the like. Electronic components can be passive or active.

[0028] The term "electronic device" or "system" refers to a physical entity formed from one or more electronic components to perform a predetermined function on electrical signals.

[0029] It should be understood that in any drawings of an electronic device, a series of electronic components connected by lines (e.g., wires) indicates that such electronic components are in electrical communication with each other. In addition, when a line directs one electronic component to connect to another electronic component, these electronic components can be connected to each other as described above.

[0030] abbreviation:

[0031] "AC" means alternating current.

[0032] "DAB" means Dual Active Bridge.

[0033] "DC" means direct current.

[0034] "DCDC" means direct current to direct current.

[0035] "HV / LV" means high voltage to low voltage.

[0036] Typically, a DC / DC converter system is provided that includes two (or more) secondary-side switching networks. Each switching network typically includes an input / output voltage ratio with independent control, which can enforce a phase shift between the primary and secondary-side H-bridges.

[0037] Now refer to Figure 1A 、 Figure 1B and Figure 1C , provides a schematic diagram of a direct current / direct current (DC / DC) converter and a transformer included therein. In a variation, a DC / DC converter system 10 includes a primary stage 12 and a secondary stage 14. In this context, the primary stage 12 and the secondary stage 14 may also be referred to as the primary side 12 and the secondary side 14. The primary stage 12 is configured to receive a DC voltage VDC1 as an input, while the secondary stage is configured to output a DC voltage VDC2. Typically, DC voltage VDC2 is less than DC voltage VDC1. In a refinement, the input DC voltage VDC1 is in the range of 230 to 650 volts, while the output voltage VDC2 is in the range of approximately 10 to 18 volts. Typically, DC voltage VDC1 is approximately 400 volts, while voltage VDC2 is approximately 12 volts. In a refinement, the DC / DC converter system 10 is bidirectional. Therefore, the converter system can operate with the roles of VDC2 and VDC1 reversed, i.e., DC voltage VDC2 can be the input and DC voltage VDC1 can be the output.

[0038] The DC / DC converter system 10 also includes transformer components 18 and 18' (and optionally 18"). The first transformer component 18 includes a plurality of primary windings 20 and a plurality of secondary windings 24. The second transformer component 18' includes a plurality of primary windings 20' and a plurality of secondary windings 24'. Similarly, any additional transformer components (such as the third transformer component 18") also include a plurality of primary windings 20" and a plurality of secondary windings 24".

[0039] The primary side AC voltage VAC1 is received across the primary windings 20, 20' and 20", where each of the transformer components 18, 18' and any additional transformer components 18" outputs a secondary side AC voltage VAC2, VAC2' and VAC2". Therefore, the AC voltage VAC1 is shared between (distributed among) the primary windings 20, 20' and 20". In one example, the distribution is equal (i.e., 1 / 2 for two primary windings and 1 / 3 for three primary windings). In certain specific cases (where the secondary conditions are transferred to the corresponding primary conditions), this sharing may be different. Figure 1B A variation is depicted in which the transformer further comprises one or more additional pluralities of primary windings 20 ″ connected in series with the first and second pluralities of primary windings 20 , 20 ′.

[0040] In a variation, a first phase difference between the first plurality of secondary windings 24 and the first plurality of primary windings 20, and a second phase difference between the second plurality of secondary windings 24' and the second plurality of primary windings 20' are adjusted (e.g., optimized) to improve conversion efficiency. In the refinement, the first phase difference and the second phase difference are adjusted based on the input-to-output voltage ratio, such that conversion efficiency is improved compared to a case where the first phase difference and the second phase difference are zero. Thus, the first phase difference and the second phase difference can range from 0 degrees to 180 degrees.

[0041] In another variation, when the DC-DC converter 10 includes a third transformer component 18", the third transformer component 18" includes a third plurality of primary windings 20" and a third plurality of secondary windings 24". The third transformer component 18" receives a third portion of the primary-side AC voltage and outputs a third secondary-side AC voltage. Characteristically, the third plurality of primary windings 20" is connected in series with the first plurality of primary windings 20 and the second plurality of primary windings 20'. Furthermore, the outputs from the first plurality of secondary windings 24, the second plurality of secondary windings 24', and the third plurality of secondary windings 24" are combined to form the output DC voltage VDC2. In a refinement, the second plurality of secondary windings 24' and the third plurality of secondary windings 24" are set to the same phase difference relative to the first plurality of primary windings 20 and the second plurality of primary windings 20'. In another refinement, when the input / output voltage ratio is below a predetermined threshold, the phase opposition between the two secondary windings is fixed to produce functional cancellation. The predetermined threshold is a value that separates a high input / output voltage ratio from a low input / output voltage ratio. For example, the threshold may be approximately 35.

[0042] The characteristics are, Figure 1A 、 Figure 1B and Figure 1C As depicted, primary windings 20 and 20 ′ (and any additional primary windings 20 ″) are arranged in series. Transformers 18 , 18 ′, and 18 ″ each also include a core 28 , 28 ′, and 28 ″, respectively, each of which is typically a magnetic core. Each core 28 , 28 ′, and 28 ″ may provide electrical separation of primary stage 12 from secondary stage 14 .

[0043] In a refinement, primary windings 20, 20' (and 20", if present) are part of the primary stage, and secondary windings 24, 24' (and 24", if present) are part of the secondary stage. Primary windings 20, 20' (and 20", if present) are in electrical communication with primary-side switching network 16, and secondary windings 24 and 24' (and 24", if present) are in electrical communication with secondary-side switching networks 30 and 30' (and 30", if present), respectively.

[0044] Characteristically, the DC secondary side switch networks 30, 30' and 30" complete the conversion to the output voltage. The secondary side switch networks 30, 30' and any additional switch networks 30" receive the secondary AC voltages VAC2, VAC2' and VAC2", and the output DC voltages VDC2, VDC2' and VDC2" are output from the secondary transformer windings. In another improvement, the secondary transformer windings are capable of inducing a short circuit effect in the corresponding primary coils. In this case, the other primary windings (i.e., the primary windings not associated with the short-circuited secondary) will see an increased AC voltage while their respective secondaries also receive a higher AC voltage.

[0045] Still refer to Figure 1A and Figure 1B , primary-side switching network 16 may include a primary-side H-bridge circuit. Thus, primary-side switching network 16 includes switches SP1, SP2, SP3, and SP4. Primary-side switching network 16 includes a first H-bridge leg 36 and a second H-bridge leg 38. In first H-bridge leg 36, the source of transistor switch SP1 is connected to first input terminal Tp1 of primary winding 20 of transformer 18. The drain of transistor switch SP1 is connected to the positive side of primary-side voltage bus VPB1, which is in electrical communication with the positive side of DC input voltage VDC1. The source of transistor switch SP1 is also connected to the drain of transistor switch SP2. Thus, the source of transistor switch SP1 and the drain of transistor switch SP2 are both connected to the first input terminal Tp1 of the series combination of the primary windings 20, 20', 20". The source of transistor switch SP2 is in electrical communication with the negative side of the primary-side voltage bus VPB1, and therefore with the negative side of the DC input voltage DCV1. Similarly, in the second H-bridge arm 38, the source of transistor switch SP3 is connected to the second input terminal Tp2 of the series combination of the primary windings 20, 20', 20". The drain of transistor switch SP3 is connected to the positive side of the input voltage VDC1. The source of transistor switch SP3 is also connected to the drain of transistor switch SP4. Thus, the source of transistor switch SP3 and the drain of transistor switch SP4 are connected to the second input terminal Tp2 of the series combination of the primary windings 20, 20', 20". The source of transistor switch SP4 is in electrical communication with the negative side of the input voltage VDC1. During operation, when the primary stage receives the DC input VDC1, the primary side switching network 16 enables or establishes the first AC voltage VAC1 to be applied to the transformer 18 by generating positive and negative voltages that are alternately applied to the transformer.

[0046] The present embodiments are not limited by a particular topology of the secondary stage. Typically, the secondary side switch networks 30, 30' (and any additional switch networks 30") are configured to convert the secondary stage AC voltage VAC2, VAC2' (and VAC2", if required) to an output DC voltage VDC2. Figure 1A A specific example of such a topology is provided that includes a second switch network 46, which is disclosed in U.S. Provisional Patent No. 63067206 filed on August 18, 2020. Typically, each secondary-side switch network 30 and 30' can each include an H-bridge circuit. Thus, the first secondary-side switch network 30 includes a first secondary-side H-bridge arm 40 and a second secondary-side H-bridge arm 42. Similarly, the second secondary-side switch network 30' includes a first secondary-side H-bridge arm 40' and a second secondary-side H-bridge arm 42'. The first H-bridge arm 40 includes a first transistor switch SS1 and a second transistor switch SS2, while the second H-bridge arm 42 includes a third transistor switch SS3 and a fourth transistor switch SS4. Similarly, the first H-bridge arm 40' includes a first transistor switch SS1' and a second transistor switch SS2', while the second H-bridge arm 42' includes a third transistor switch SS3' and a fourth transistor switch SS4'.

[0047] A feature of this embodiment is that each switching network 30, 30' (and any additional switching networks) is independently controlled. In a refinement, when there are two switching networks 30, 30', the converter can be controlled so that there are different phase shifts between them (from 0° or in-phase to 180° or anti-phase).

[0048] exist Figure 1A In the specific example depicted, the plurality of secondary windings 24 includes a first group of secondary windings L1 and a second group of secondary windings L2. Similarly, the plurality of windings 24' includes a first group of secondary windings L1 and a second group of secondary windings L2. The primary-side switching network 16 and the secondary-side switching networks 30, 30', and 30" (if present) are operated so that a first current I(L1) flows through the first group of secondary windings L1 from contact Ts1 to contact Tc, a second current I(L2) flows through the second group of secondary windings L2 from contact Ts2 to contact Tc, and a third current Ip flows through the primary windings 20, 20', and 20" (if present). Characteristically, the first current, the second current, and the third current are at least partially established by mutual inductance between the primary winding and the secondary winding.

[0049] In a variation, the converter 10 further includes a microcontroller 50 configured to control the transistor switches in the primary-side switching network 16 and the secondary-side switching network 30 , 30 ′. In a refinement, the microcontroller 50 can send control signals to the gates of the transistor switches SP1, SP2, SP3, and SP4. In this regard, transistor switches SP1 and SP4 form a first primary-side H-bridge and are simultaneously turned on and off by the control signal. Similarly, transistor switches SP2 and SP3 form a second primary-side H-bridge on the primary side and are simultaneously turned on and off by the control signal. The first and second primary-side H-bridges are alternately actuated by the control signal. Therefore, the control signal for the first primary-side H-bridge is out of phase (typically 180°) with the second primary-side H-bridge. This causes the voltage output of the first primary-side H-bridge to be out of phase with the output voltage of the second primary-side H-bridge.

[0050] The microcontroller 50 may also send control signals to the gates of transistor switches SS1, SS2, SS3, SS4, SS1′, SS2′, SS3′, SS4′, SS1″, SS2″, SS3″, and SS4″. At this point, transistor switches SS1 and SS4 (or SS1′ and SS4′ or SS1″ and SS4″) form a first primary-side H-bridge and are simultaneously turned on and off by the control signal. Similarly, transistor switches SS2 and SS3 (or SS2′ and SS3′ or SS2″ and SS3″) form a second primary-side H-bridge on the secondary side and are simultaneously turned on and off by the control signal. The first secondary-side H-bridge and the second secondary-side H-bridge are alternately actuated by the control signal. Therefore, the control signal for the first secondary-side H-bridge is out of phase (typically 180°) with the second secondary-side H-bridge. This causes the voltage output of the first secondary-side H-bridge to be out of phase with the output voltage of the second secondary-side H-bridge. Although the present invention is not limited by the type and frequency of the control signal, a frequency of approximately 20 to 120 kHz may be used. The control signal may be a square wave or any other suitable waveform.

[0051] In the DC / DC converter system configuration described above, the performance of the converter can be improved by adjusting the modulation of each secondary switching unit or deactivating them according to the operating voltage range, so that when the primary and secondary voltages are at higher or lower voltage values, the converter exceeds the nominal design desired conditions. This allows the primary voltage to be adapted to the operating conditions of effective operation (the converter basically operates as a multi-level converter, in which the output voltage (i.e., the primary voltage in the present invention) is controlled by the number of effective levels (i.e., the secondary switching units in the present invention) and their modulation).

[0052] Figure 2A and Figure 2B The output current of a full-bridge stage is provided with the contribution of each of the three secondary windings. Figure 2AFigure 1 shows standard operation with the secondary windings operating in phase. This operation is challenging for extreme voltages, as shown in the simulation (250V lower limit), because the difference between the primary and secondary voltages increases the primary current. Figure 2B As depicted, the proposed topology enables the use of phase shifting to offset the voltage in the secondary winding, so that the voltage reflected in the primary winding is closer to the voltage in the primary bus, thereby reducing the primary current for the same processing power. In an example, a reduction factor of 1.7 in primary current is achieved for the same processing power. It should be appreciated that this solution can be used for any combination of input / output voltages.

[0053] Equation 1 below provides a control method by setting the DC high voltage current:

[0054]

[0055] in:

[0056] I dc (HV): DC high voltage current target. I dc (HV) is determined by the secondary power requirement (V lv *Ilv) and input V hv The voltage (VDC1) is calculated, where V lv is the low voltage (VDC2), Ilv is the current at output IDC2;

[0057] FI n : offsets the primary to one of the corresponding active secondaries (the range of active secondary is 0 to 0.25 (design constraint)). FI is the offset of the switching sequence of the secondary full bridge relative to the switching sequence of the primary full bridge. When I dc (HV), V lv 、f sw When and L are known, FI is calculated by the above formula 1. Figure 1B In the system, FIin=FI;

[0058] L: equivalent transformer leakage inductance;

[0059] f sw : variable frequency [e.g. 50..250kHz], as output power (I dc ·V lv ) function.

[0060] V lv : low voltage;

[0061] n: Equivalent primary to secondary transformer ratio (function of active secondary). Effective transformer turns ratio, which is the ratio of V hv / V lv function).

[0062] Example of control of a DCDC system with 3 active secondaries (see Figure 2A ):

[0063] For the 3 secondaries, when V hv / V lv ↑↑ (i.e., when the ratio is 450V / 8V): FI1=FI2=FI3=FI, then n=3·n p / n s , where n p is the number of turns of the transformer winding at the primary, n s is the number of transformer winding turns at the secondary. The 3 in this formula represents the number of active secondaries (all with the same FI, and therefore all contributing to power transfer) on the applied FI, which is calculated according to Formula 1. In this case, (V hv / V lv High) all secondaries have the same FI as calculated in Equation 1. Figure 2A As shown, all three secondaries are in phase, but delayed "FI" relative to the primary.

[0064] Control example for a DCDC system with 1 active secondary (see Figure 2B ):

[0065] For a secondary, when V hv / V lv ↓↓ (i.e., when the ratio is 250V / 16V): FI1 = FI, FI2 = 0, FI3 = 0.5, then n = 1·n p / n s , where n p is the number of turns of the transformer winding at the primary, and n s is the number of transformer winding turns at the secondary, and 1 in the formula is the number of active secondaries. In this case (V hv / V lv Low),( Figure 2B The two secondaries of 3 in FIG have fixed FI. The second secondary 24′ has an FI fixed to 0 (in phase with the primary), and the third secondary 24″ has an FI fixed to 0.5 (out of phase with the primary), leaving only the first secondary 24 to operate at the calculated FI. Since the secondaries 2, 24′ and 3, 24″ have opposite phases, the primary power transfer is cancelled and only the first secondary operates effectively, regulated by the FI calculated with the interpreted n value. In this case (V hv / V lv Low), only one secondary has FI according to Formula 1. For the other cases, FI is fixed to 0 and 0.5 respectively.

[0066] Although exemplary embodiments have been described above, this does not mean that these embodiments describe all possible forms of the present invention. On the contrary, the words used in this specification are illustrative rather than restrictive, and it should be understood that various changes can be made without departing from the spirit and scope of the present invention. In addition, the features of different implementation embodiments can be combined to form additional embodiments of the present invention.

[0067] Aspects of the present disclosure may be implemented in one or more of the following embodiments:

[0068] Item 1): A DC-DC converter that converts an input DC voltage into an output DC voltage, the DC-DC converter comprising:

[0069] a primary-side switching network receiving the input DC voltage and outputting a primary-side AC voltage;

[0070] a first transformer component comprising a first plurality of primary windings and a first plurality of secondary windings, the first transformer component receiving a first portion of the primary side AC voltage and outputting a first secondary side AC voltage;

[0071] a second transformer component comprising a second plurality of primary windings and a second plurality of secondary windings, the second transformer component receiving a second portion of the primary side AC voltage and outputting a second secondary side AC voltage, wherein the first plurality of primary windings are connected in series with the second plurality of primary windings;

[0072] a first secondary-side switching network receiving the first secondary-side AC voltage; and

[0073] A second secondary side switching network receives the second secondary side AC voltage, wherein outputs from the first and second pluralities of secondary windings are combined to form the output DC voltage.

[0074] Item 2): A DC-DC converter according to Item 1), wherein a first phase difference between the first plurality of secondary windings and the first plurality of primary windings and a second phase difference between the second plurality of secondary windings and the second plurality of primary windings are adjusted to improve conversion efficiency.

[0075] Item 3): A DC-DC converter according to Item 2), wherein the first phase difference and the second phase difference are adjusted according to the input-output voltage ratio, so that the conversion efficiency is improved compared to the case where the first phase difference and the second phase difference are zero.

[0076] Item 4): The DC-DC converter according to item 2), wherein the first phase difference and the second phase difference are 0 degrees to 180 degrees.

[0077] Item 5): The DC-DC converter according to Item 1) further includes a third transformer component, wherein the third transformer component includes a third plurality of primary windings and a third plurality of secondary windings, and the third transformer component receives a third part of the primary side AC voltage and outputs a third secondary side AC voltage, wherein the third plurality of primary windings are connected in series with the first plurality of primary windings and the second plurality of primary windings.

[0078] Item 6): A DC-DC converter according to Item 5), wherein the first plurality of secondary windings, the second plurality of secondary windings, and the third plurality of secondary windings are set to the same phase difference relative to the first plurality of primary windings, the second plurality of primary windings, and the third plurality of primary windings, respectively, to produce conversion within a predetermined high nominal input / output voltage ratio range.

[0079] Item 7): The DC-DC converter according to item 5), wherein when the input / output voltage ratio is lower than a predetermined threshold, the phase opposition in the two secondaries is fixed to produce functional cancellation.

[0080] Item 8): The DC-DC converter according to item 1), wherein when the input DC voltage is approximately 230 to 650 volts.

[0081] Item 9): The DC-DC converter according to item 1), wherein the primary side includes the primary side switching network and the first plurality of primary windings and the second plurality of primary windings.

[0082] Item 10): A DC-DC converter according to item 9), wherein the secondary side includes a first plurality of secondary windings and a second plurality of secondary windings, the first secondary side switch network and the second secondary side switch network.

[0083] Item 11): The DC-DC converter according to item 1), wherein the primary-side switching network comprises a primary-side H-bridge circuit.

[0084] Item 12): The DC-DC converter according to item 11), wherein the first secondary-side switching network comprises a first secondary-side H-bridge circuit.

[0085] Item 13): The DC-DC converter according to item 12), wherein the second secondary-side switching network comprises a second secondary-side H-bridge circuit.

[0086] Item 14): The DC-DC converter according to item 1) further includes a microcontroller configured to control the primary-side switching network.

[0087] Item 15): The DC-DC converter according to item 14), wherein the microcontroller is further configured to control the first secondary-side switch network and the second secondary-side switch network.

[0088] Item 16): The DC-DC converter according to item 1), wherein the output DC voltage is lower than the input DC voltage.

[0089] Item 17): The DC-DC converter according to item 1) further includes a third transformer component, wherein the third transformer component includes a third plurality of primary windings and a third plurality of secondary windings.

[0090] Item 18): The DC-DC converter according to item 1), which is configured to be bidirectional.

[0091] Item 19): A DC-DC converter according to Item 1), wherein a first phase difference between the first plurality of secondary windings and the first plurality of primary windings and a second phase difference between the second plurality of secondary windings and the second plurality of primary windings are adjusted according to an input-to-output voltage ratio, so that the conversion efficiency of the DC-DC converter is improved compared to a case where the first phase difference and the second phase difference are zero.

Claims

1. A DC-DC converter that converts an input DC voltage into an output DC voltage, the DC-DC converter comprising: a primary-side switching network receiving the input DC voltage and outputting a primary-side AC voltage; a first transformer component comprising a first plurality of primary windings and a first plurality of secondary windings, the first transformer component receiving a first portion of the primary side AC voltage and outputting a first secondary side AC voltage; a second transformer component comprising a second plurality of primary windings and a second plurality of secondary windings, the second transformer component receiving a second portion of the primary side AC voltage and outputting a second secondary side AC voltage, wherein the first plurality of primary windings are connected in series with the second plurality of primary windings; a third transformer component comprising a third plurality of primary windings and a third plurality of secondary windings; a first secondary-side switching network receiving the first secondary-side AC voltage; and a second secondary side switching network receiving the second secondary side AC voltage, wherein outputs from the first plurality of secondary windings and the second plurality of secondary windings are combined to form the output DC voltage, wherein when a ratio between the input DC voltage and the output DC voltage is below a predetermined threshold, the anti-phase of two of the first, second, and third pluralities of secondary windings are fixed to produce functional cancellation.

2. The DC-DC converter according to claim 1, wherein: A first phase difference between the first plurality of secondary windings and the first plurality of primary windings and a second phase difference between the second plurality of secondary windings and the second plurality of primary windings are adjusted to improve conversion efficiency.

3. The DC-DC converter according to claim 2, wherein: The first phase difference and the second phase difference are adjusted according to a ratio between the input DC voltage and the output DC voltage, so that the conversion efficiency is improved compared to a case where the first phase difference and the second phase difference are zero.

4. The DC-DC converter according to claim 2, wherein: The first phase difference and the second phase difference are 0 degrees to 180 degrees.

5. The DC-DC converter according to claim 1, wherein The third transformer component receives a third portion of the primary side AC voltage and outputs a third secondary side AC voltage, wherein the third plurality of primary windings are connected in series with the first and second pluralities of primary windings.

6. The DC-DC converter according to claim 5, wherein: The first plurality of secondary windings, the second plurality of secondary windings, and the third plurality of secondary windings are respectively arranged with the same phase difference relative to the first plurality of primary windings, the second plurality of primary windings, and the third plurality of primary windings to produce conversion within a predetermined high nominal input / output voltage ratio range.

7. The DC-DC converter according to claim 1, wherein: The input DC voltage is 230 to 650 volts.

8. The DC-DC converter according to claim 1, wherein The primary side includes the primary side switching network and the first and second pluralities of primary windings.

9. The DC-DC converter according to claim 8, wherein: The secondary side includes the first and second pluralities of secondary windings, the first and second secondary side switching networks.

10. The DC-DC converter according to claim 1, wherein The primary-side switching network includes a primary-side H-bridge circuit.

11. The DC-DC converter according to claim 10, wherein: The first secondary-side switching network includes a first secondary-side H-bridge circuit.

12. The DC-DC converter according to claim 11, wherein: The second secondary-side switching network includes a second secondary-side H-bridge circuit. 13 . The DC-DC converter of claim 1 , further comprising a microcontroller configured to control the primary-side switching network.

14. The DC-DC converter according to claim 13, wherein: The microcontroller is further configured to control the first secondary-side switching network and the second secondary-side switching network.

15. The DC-DC converter according to claim 1, wherein The output DC voltage is lower than the input DC voltage.

16. The DC-DC converter according to claim 1, wherein The DC-DC converter is configured to be bidirectional.

17. The DC-DC converter according to claim 1, wherein: A first phase difference between the first plurality of secondary windings and the first plurality of primary windings, and a second phase difference between the second plurality of secondary windings and the second plurality of primary windings are adjusted according to a ratio between the input DC voltage and the output DC voltage, so that the conversion efficiency of the DC-DC converter is improved compared to a case where the first phase difference and the second phase difference are zero.

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