Direct current power converter

Abstract

A direct current power converter DPX, connected with a primary port comprising a DC or AC power source and a secondary port comprising a DC or AC load; comprising a transformer or autotransformer; a first power switch between two nodes, having two power terminals and a first control terminal; a second power switch between two other different nodes, having two power terminals and a second control terminal, wherein said switches are configured to connect the primary port power source to the secondary port load through the transformer or autotransformer. The cited first and second power switches are configured to operate simultaneously under the action of a logic control signal, providing an on state in which all power switches are simultaneously in an open state or all power switches are simultaneously in a closed state, connecting or disconnecting said transformer simultaneously with said primary port and said secondary port.

Description

TECHNICAL FIELD

[0001] The present invention relates in a first aspect to a power converter comprising a transformer or autotransformer to connect a primary port comprising a DC or AC power source to a secondary port comprising a DC or AC load,

[0002] The present invention thus belongs to the field of power converters that handle power from a DC or AC input power source to a DC or AC load output, where power can flow bi-directionally, requiring only to exchange power source and load.

[0003] DC / DC power conversion units can be used to implement DC / AC, AC / AC and AC / DC power converters.

[0004] In this description, the concept of Figure of Merit is used in power converters, according to the following definition.

[0005] The typical Figure of Merit (FOM) for high density power converters is "power loss" times "volume". A more specific FOM for high current converters is "conduction power loss of power switches" times "footprint of power switches". Assuming that all power switches in the DC ports of a DC-DC converter have the same area, the simplified FOM * port can be normalized to FOM port as follows:

[0006]

[0007]

[0008] j denotes each power switch (inverter power switch or rectifier power switch) in the DC port, i j_rms denotes the RMS value of the current flowing through each power switch, I port denotes the average value of the current flowing into or out of each DC port.

[0009] The present invention relates in a second aspect to a three power terminal power switch device 3PTPS suitable for use in a variety of power converter topologies.

[0010] Although the present invention relates to a three power terminal power switch, embodiments involving a four or more additional power terminals are also included in this description. BACKGROUND

[0011] In 1966, Moore and T.G. Wilson published a foundational paper entitled "Basic Considerations for DC to DC Conversion Networks." In 1969, Dr. Dan Holden Wolaver of MIT publicly disclosed his doctoral thesis entitled "Fundamental study of DC to DC conversion systems." Both works indicated that in a switched mode DC-DC converter, at least one power switch produces "AC" or "indirect" power and at least one power switch rectifies the "AC" power back to "DC" power. At that time, power switches were represented by variable resistors. "Rac" and "Rdc" refer to the inverter power switch and the rectifier power switch.

[0012] These power switches alternate between being on and off, which means that at least one power switch is operating at a duty cycle of less than or equal to 50%.

[0013] Typical switched mode power topologies for power converters are Buck, Boost, Buck-Boost, Sepic / Cuk, Zeta, Flyback, and Flyback with two power switches, Active Clamp / Single Power Switch / Two Power Switch Forward, Push-Pull, Weinberg, Half-Bridge, Full-Bridge, Phase-Shifted Full-Bridge, Resonant LLC, and many others that are more complex in their technical level.

[0014] Due to the demand for high power by complex loads such as microprocessors, CPUs, GPUs, and XPU's (including artificial intelligence integrated circuits and service devices, electric vehicles, communications, and other electrical devices), the demand for small, high performance, and high efficiency power converters is growing.

[0015] Switched mode DC-DC power converters, including DC-AC, AC-DC, and AC-AC power converters composed of quasi-static DC-DC cells, include two power switches or more. Power switches include power transistors (controllable devices) and power diodes (non-controllable devices). One of the power switches (controllable device) produces "AC power," also known as "indirect power," which requires voltage (or current) gain regulation to be implemented. The second power switch (diode in a unidirectional power converter or transistor, or transistor in a bidirectional converter) needs to rectify the "AC" or "indirect" power and provide it to the output port.

[0016] The basic cell of a DC-DC power converter is the Buck (step-down). Boost (step-up) and Buck-boost (step-up / step-down), where two power switches are not simultaneously on.

[0017] The duty cycle "d" is defined as the fraction of the switching period (T) during which the power switch is on (ton), i.e. d = ton / T. Since the two power switches are alternately on, not simultaneously on, the duty cycle of at least one power switch is lower than or equal to 50%.

[0018] There are many dual power terminal power switches on the market that are co-packaged. These power switches are independently driven, alternately driven in the power supply.

[0019] In some cases, the two alternately switched are driven with a single logic control signal, because their on and off states are determined by complementary logic.

[0020] In other cases, the two power switches are connected in parallel, forming a single dual power terminal power switch, which has better performance (i.e. on-resistance) than a single power switch.

[0021] The present invention has nothing to do with the known dual power switch configuration shown in Figure 2B, because the difference compared to the three power terminal power switch embodiment of the present invention is that, finally, all the power switches of the power converter are configured to operate simultaneously in the on state and simultaneously in the off state, so that, under the action of a single logic control signal (100a), i.e. all different power switches are simultaneously in the on state or simultaneously in the off state.

[0022] US2003090237, JP2011130552, EP1115203 and US2013181723 disclose three power terminal power switch devices, where all the power switches are not simultaneously operated in the on state or off state.

[0023] In US2003090237, switches 128 and 130 (see Figure 1) are operated out of phase (i.e. alternately) by a logic control signal (e.g. a single gate driver). This is possible because switches 128 and 130 are of different types (N-channel and P-channel), and one switch 128 is on at a high logic level and the other 130 is on at a low logic level.

[0024] In patents US4561046 and US5521807, the "resonant reset" strategy for transformers is implemented. In both cases, compared to the present invention, additional circuits are necessary for the operation of the circuit. In US4561046, at least an LC output filter and a diode are necessary for storing and delivering AC energy and for facilitating voltage regulation. In US5521807, at least an auxiliary winding in the "flyback" connection is responsible for demagnetizing the transformer.

[0025] In the prior art, the duty cycle of the power switches of the basic cell is d ac and d dc Since the power switches are not simultaneously on, but are alternately on, d ac +d dc ≤ 1 always applies.

[0026] The power supply topology of the prior art uses alternating power switches, so the optimal FOM (the lower the better) of the power switches of the input and output ports cannot be chosen independently. Figure 3C It is shown that a high value of the duty cycle (i.e. 90%) (point B) gives the optimal FOM. In the prior art converter, if a high duty cycle is chosen for one of the ports (input or output), the other port (output or input) works with a low duty cycle (i.e. 10%) and is accompanied by a worse (higher) FOM (point A).

[0027] Conversely, in the present invention, both the switches of the input and output ports can work with a good FOM (d > 50%, i.e. 90%) since both switches are simultaneously on and simultaneously off.

[0028] In the present invention, the resonant reset demagnetization occurs between the magnetizing inductance and the parasitic (or additional) capacitance and does not require any of the additional circuits mentioned above. SUMMARY

[0029] The present invention relates to a power converter configured to connect a primary port with a secondary port, the primary port comprising a DC or AC power source, the secondary port comprising a DC or AC load, and according to the mentioned prior art, therefore comprising:

[0030] a transformer or autotransformer and optionally a passive network of capacitors, inductors or resistors connected to a plurality of nodes of the power converter;

[0031] a first power switch between two nodes of said plurality of nodes, the first power switch having two power terminals and at least a first control terminal; and

[0032] at least a second power switch between other different two nodes of the plurality of nodes, the at least second power switch having two power terminals and at least a second control terminal;

[0033] wherein the first power switch and the at least second power switch are configured to be interconnected with the cited plurality of nodes; and

[0034] wherein the at least first and second control terminals of the first and second power switches are different terminals or a single terminal.

[0035] According to the present invention, the cited first and at least second power switches connect an input DC or AC port power supply with an output DC or AC load through a transformer or autotransformer, providing power transfer only through a DC path, not generating and not storing "AC power" to regulate power conversion, and these power switches are configured to be operated under the action of a logic control signal, providing a conducting state when all power switches are simultaneously in an open state or all power switches are simultaneously in a closed state, connecting or disconnecting the transformer or autotransformer simultaneously with the primary port and the secondary port, and forming a direct current power converter DPX.

[0036] Under these conditions, the open state time of all power switches simultaneously activated in a given time period provides a conduction duty cycle even higher than 50% in all power switches, thus reducing the RMS value of the current flowing through the power switches for a given average converter input and output current.

[0037] In one embodiment, the cited first and at least second power switches are integrated in a single structure of three power terminals, and the first and at least second power switches are connected together in a common node. The cited structure provides a three power terminal power switch device whose single control terminal replaces the control terminals of the first and at least second power switches. The logic control signal is applied to the single control terminal of the device.

[0038] Power stage circuit topologies vary widely, including additional power switches, transistors or diodes, and can include transformers. Typical circuit topologies are "Flyback", "Forward", "Push-pull", "Half-Bridge" and "Full-Bridge". These circuit topologies also have "Current Fed" versions and identical "Resonant" versions. There are also a variety of output filters, including C, LC and "Current Doubler". Some additional active or passive networks can be added to achieve soft switching (zero voltage or zero current switching). In some cases, several basic cells are interconnected and simplified by removing some redundant power switches, such as Sepic, Cuk or Zeta converters. Transformers can also be included in their structure.

[0039] All of them have in common that, in the case of d> 50%, they do not operate all the power switches. Even if there is one less switch in d> 50%, at least one power switch operates in d< 50%. An extreme case is to have all power switches operating at 50%. There are no power converters in switch mode where d> 50% for all power switches of the power topology.

[0040] In the proposed invention, because there is no need for AC power to provide DC-DC conversion (see Figure 3A ), there is no inversion and rectification of power switches.

[0041] Instead, power flows directly from input to output through a magnetic element, and voltage conversion is achieved by the turns ratio of a transformer or autotransformer, through Figure 3A both power switches in the DC path are connected to the input and output ports simultaneously, instead of on the AC path (see Figure 1).

[0042] In this way, all the power switches involved are activated simultaneously, providing power transfer through the DC path, which can operate with a duty cycle greater than 50%. During the on state, the magnetization of the transformer or autotransformer is reset during the off state through the resonance between the magnetizing inductance of the transformer or autotransformer and the parasitic (or parallel) capacitance of the power switches.

[0043] In one embodiment, the power converter includes additional control means configured to provide additional timing control, which can advance or delay the physical drive signal corresponding to the logical control signal applied to each power switch during the transition between said on and off states, in order to reduce switching losses.

[0044] In one embodiment, the first or at least the second power switch is inserted in or part of a winding of a transformer or autotransformer, coupled in the same magnetic element.

[0045] The at least two first and second power switches of the power converter involved are either both controlled switches implemented with transistors, or comprise at least one controlled switch implemented with a transistor and at least one uncontrolled switch implemented with a diode.

[0046] Alternatively, the at least two first and second power switches are implemented with electromechanical devices.

[0047] Furthermore, the on-state time of the power switches of the power converter should be long enough to provide a current through the secondary winding of the transformer or autotransformer to reach a steady state, whereby the gain of the converter does not depend on the specific duration of this on-state time.

[0048] However, in another embodiment, the gain of the power converter can be adjusted by using the leakage inductance of the power transformer or autotransformer or an additional inductance in series, thereby varying the duty cycle and / or the switching frequency of the power switches, wherein the on-time of the switches is not long enough to reach a steady state of the current flowing through the power switches within a switching period.

[0049] The power converter of the present invention and the three power terminal power switching device involved can be implemented using semiconductor technology selected from Si, GaN, SiC or other semiconductors, comprising one or more of the following components: a junction or heterojunction, a heterostructure, a piezoelectric structure, a metal-oxide-semiconductor field-effect transistor, an insulated-gate bipolar transistor, a bipolar junction transistor, a gate turn-off thyristor or a combination thereof.

[0050] Further features of the present invention will be described in detail hereinafter. BRIEF DESCRIPTION OF DRAWINGS

[0051] Fig. 1 schematically illustrates the concept of power transfer between a DC power source and a load in a conventional power converter, more specifically according to a switched mode power supply (SMPS), comprising two power switches, the first one acting as an inverter power switch and the second one acting as a rectifier power switch, wherein in operation one power switch is in an on-state and the other one is in an off-state, and vice versa.

[0052] Fig. 2A shows an embodiment of a prior art power device with two power switches.

[0053] Fig. 2B shows an embodiment of a power device with a dual power switch configuration similar to Fig. 2A.

[0054] Figure 3AThe power transfer concept using the power converter of the present application, i.e. a DC power converter DPX, is schematically shown, with the involved power switches simultaneously activated, providing only power transfer through the DC path, without generating AC power, implementing power conversion.

[0055] Figure 3B The duty cycle of the involved power switches simultaneously activated is shown.

[0056] Figure 3C The quality factor of the inverter and rectifier combination of the power switches is shown as a function of its duty cycle.

[0057] Figure 4 An embodiment of the present application is shown, where the power switches are all simultaneously in the on state or in the off state, with the first and second power switches integrated in a single structure comprising three power terminals, forming a three power terminal power switch (3PTPS).

[0058] Figure 5A The electrical symbol of the three power terminal power switch of the present application is shown.

[0059] Figure 5B The electrical symbol of the three power terminal power switch in the on state is shown.

[0060] Figure 5C The electrical symbol of the three power terminal power switch in the off state is shown.

[0061] Figure 6 The circuit of a power converter according to the present application, with a three power terminal power switch or comprising more power switches, is shown with dashed lines.

[0062] Figure 7A An embodiment of the circuit of a power converter according to the present application, with a transformer comprising two power switches configured to operate simultaneously, is shown.

[0063] Figure 7B Equivalent to Figure 7A Using a 3PTPS as power switch.

[0064] Figure 8A An embodiment of the circuit of a power converter according to the present application, with a autotransformer comprising two power switches configured to operate simultaneously, is shown.

[0065] Figure 8B The circuit of the autotransformer in Figure 8A is shown in another arrangement.

[0066] Figure 8C With Figure 8Bcorresponding to the circuit of Figure 1, using a three-terminal power switching device (3PTPS).

[0067] Figure 9 is another embodiment of a circuit with a transformer according to the present application, the transformer comprising two power switches configured to operate simultaneously.

[0068] Figure 10 is an embodiment comprising a controlled switch implemented with a transistor and an uncontrolled switch implemented with a diode.

[0069] Figure 11A is shown another embodiment according to the present application, the transformer comprising two power switches configured to operate simultaneously, one of the power switches being included between windings or parts of windings of the transformer, coupled in the same magnetic structure.

[0070] Figure 11B is shown Figure 11A a circuit with a transformer and insulation instead of a transformer.

[0071] Figure 12A is shown Figure 9 the same embodiment of a circuit according to the present application, with a transformer comprising two power switches configured to operate simultaneously, but in which energy flows in opposite directions, demonstrating the bidirectional nature of the power converter.

[0072] Figure 12B is shown Figure 12A a circuit with a 3PTPS device.

[0073] Figure 13A is shown a circuit with a transformer and multiple outputs according to the present application, comprising two power switches configured to operate simultaneously.

[0074] Figure 13B is a circuit with a 3PTPS device. Figure 13A

[0075] Figure 14 is shown an equivalent circuit of the power converter of the present application, comprising two power switches configured to operate simultaneously and parasitic or additional elements of the power converter.

[0076] Figure 15 is a graph illustrating the behavior of the power converter of the present application, showing details of zero voltage switching (ZVS).

[0077] Figure 16 is a graph illustrating the behavior of the power converter of the present application, showing details of zero current switching (ZCS).

[0078] Figure 17 ​is the same as Figure 10 The same as the previous embodiment, with the addition of a series leakage inductance, which can be used to adjust the gain of the converter.

[0079] Figure 18 is another equivalent circuit of the alternative embodiment.

[0080] Figure 19 Several current vs. time plots are shown in a transformer or autotransformer, in response to the influence of different values of the parasitic capacitance, illustrating that the turn-on time can be long enough that the voltage gain is not adjusted, or short enough to provide charge control, thus achieving voltage regulation. Other plots can be obtained in response to the influence of different values of the parasitic inductance.

[0081] Figure 20 and 21 A power converter is shown, comprising the integration of a Buck converter with a DPX converter of the present invention, forming a three-port Buck-DPX regulating converter.

[0082] Figure 22 A three-port Buck-DPX converter is shown acting as an "energy-buffered AC-DC power converter", where port 2 is the energy buffer, port 1 is the rectified AC voltage, and port 3 is the DC load.

[0083] Figure 23A A three-port power converter of Figure 22 is shown, illustrating the power flow from the rectified AC voltage (DC port 1) to the energy buffer (DC port 2) and the DC load (DC port 3).

[0084] Figure 23B A three-port power converter of Figure 22 is shown, illustrating the power flow from the rectified AC voltage (DC port 1) and the energy buffer (DC port 2) to the DC load (DC port 3).

[0085] Figure 23C A three-port power converter of Figure 22 is shown, illustrating the power flow from the energy buffer (DC port 2) to the DC load (DC port 3).

[0086] Figure 24 A waveform example of the voltage (dashed line) and input current in the rectified AC (DC port 1) is shown, as well as the resulting pulsed input power (dashed line), which is buffered in DC port 3 and converted to constant DC power. DETAILED DESCRIPTION

[0087] The present invention relates to a power converter configured to connect a primary port with a secondary port, the primary port comprising a DC or AC power source and the secondary port comprising a DC or AC load, comprising:

[0088] a transformer or autotransformer and optionally a passive network of capacitors, inductors or resistors connected to a plurality of nodes of the power converter;

[0089] a first power switch between two nodes of the plurality of nodes, the first power switch having two power terminals and at least a first control terminal; and

[0090] at least a second power switch between other different two nodes of the plurality of nodes, the at least second power switch having two power terminals and at least a second control terminal;

[0091] wherein the first power switch and the at least second power switch are configured to interconnect the plurality of nodes as referred to.

[0092] The present invention proposes a completely different approach which provides a power converter 2 resulting from several topologies wherein the first and at least second power switches 31, 32 are configured to operate simultaneously under the action of a logical control signal 100a, providing a conduction state when all power switches 31, 32 are simultaneously in an on state or all power switches are in an off state, connecting or disconnecting the transformer or autotransformer simultaneously with the primary port and the secondary port and forming a direct current power converter DPX.

[0093] In this way, the power switches 31, 32 are activated simultaneously in a given period of time, the on state time of all power switches 31, 32 providing a conduction duty cycle even higher than 50% in all power switches 31, 32, thus reducing the RMS value of the current flowing through the power switches 31, 32 for a given average converter output current.

[0094] The proposed power converter 2 comprises two or more power switches 31, 32 connected in series, in parallel or in a combination of series and parallel between them.

[0095] In one embodiment, the first and second power switches 31, 32 are integrated in a single structure of three power terminals 11, 12, 13; see Figure 4The single control gate of the device 100 replaces the control gates 101, 102 of the first and second power switches (see prior art embodiments of Figures 2A and 2B) and simultaneously operates both power switches 31, 32, causing the first and second power switches 31, 32 to open or close simultaneously under the action of a single logic control signal 100a, to turn on or off the different nodes, applied to the single control gate of the device 100, and to obtain a three-terminal power supply switch device 1.

[0096] The voltages and currents in the three terminals can be positive or negative, meaning the bidirectionality of the voltages and currents, so the power supply can flow from the input ports to the output ports of the device and vice versa.

[0097] In the three-terminal power supply switch device 1 according to the present invention, at least two first and second power switches 31, 32 are simultaneously opened or closed under the action of a single logic control signal 100A, applied to the single control gate of the device 100 to be connected together in series or parallel.

[0098] In the disclosed embodiment of the three-terminal power supply switch device, at least two first and second power switches 31, 32 are not connected together.

[0099] A further feature of the present invention is to optimize the quality factor of the three-terminal power supply switch device 1 by simultaneously opening or closing at least two first and second power switches 31, 32.

[0100] As previously mentioned, in the proposed power converter an additional control means is provided, configured to provide an additional timing control, to advance or delay the logic control signal applied to each power switch during the power switch transition between said common on and off states, to reduce the switching losses.

[0101] The gain of the power converter 2 of the present invention is based on the energy transfer through a transformer or autotransformer, see Figure 6 where the power converter 2 has regulated or unregulated voltage and current gain.

[0102] As shown in Figure 3A in the proposed power converter 2, the power can flow directly from the input to the output through an autotransformer.

[0103] Furthermore, the three-terminal power supply switch 1 according to the present invention is configured to operate in a quasi-static manner, which consists of a quasi-static DC-DC unit, comprising two or more power switches.

[0104] The proposed power converter can further comprise a control means adapted to:

[0105] configuring the turn-off time of all power switches by adjusting the cited logical control signal, so that at least one of the at least two power switches turns on once its own voltage is close to or equal to zero;

[0106] configuring the turn-on time of all power switches by adjusting the cited logical control signal, so that the turn-off of the at least second power switch (32) is delayed with respect to the first power switch (31), so that the second power switch (32) turns off once its own current is close to or equal to zero; and

[0107] adjusting the duty cycle of the power switches to maintain the peak voltage of the power switches under given constraints.

[0108] In one embodiment, the cited control device further comprises a leakage inductance of the power transformer or autotransformer (see Figure 17 ) or an additional inductance in series, configured to adjust the gain of the power converter to be regulated by varying the duty cycle and / or the switching frequency of the power switches, wherein the turn-on time of the switches is not sufficient to bring the current flowing through the power switches (31, 32) to steady state within the switching period.

[0109] Zero Voltage Switching ZVS:

[0110] In the power converter of the present invention, a single logical control signal 100a is adjusted so that at least one of the at least two power switch devices 31, 32 turns on, i.e. Zero Voltage Switching ZVS, once the voltage in the power switch 32 is close to or equal to zero, and wherein the voltage or current in the power switch 32 can be sensed or calculated to achieve the timing according to which the magnetizing current increases during the turn-on time of the power switch 31, while resonance occurs during the turn-off, wherein the energy stored in the magnetizing inductance is transferred to the capacitors C1 and C2, increasing their voltage to a maximum and returning to zero in a resonant manner, and wherein the turn-off time of the first power switch 31 and the second power switch 32 is determined by "sensing" the voltage or by other means of calculating the voltage in the first power switch 31 and the second power switch 32. The voltage or current in the power switches or equivalent can be sensed or calculated to achieve this timing.

[0111] To understand how ZVS is achieved, the circuit is simplified as shown in Figure 14 When the power switches are turned on at the same time, the transformer demagnetizes in a resonant manner through the parasitic capacitance.

[0112] This resonance is caused by the magnetizing inductance and the parasitic capacitance, so, referring to the capacity of the power switches from secondary to primary, we can express it with the following formula:

[0113] InFigure 15 More details of this ZVS timing can be seen in the graph of figure 1

[0114]

[0115] The magnetizing inductance of the magnetic element resonates with the parasitic or intentionally added capacitance, which is in parallel with the power switch, whose equivalent circuit is shown in figure 2 Figure 14

[0116] During the turn-on time of S1 and S2, the magnetizing current increases;

[0117] During the turn-off time, resonance occurs, in which the energy of the magnetizing inductance is transferred to the capacitances Cl and C2 in a resonant manner, increasing their voltage to a maximum value and returning to zero.

[0118] The switches S1 and S2 are turned on when the voltage across their power terminals decreases to near zero, which is known in the literature as "zero voltage switching". The turn-off time in S1 and S2 is determined by "sensing" the voltage or "estimating" or by other means calculating the voltage in S1 and / or S2.

[0119] Zero current switching ZCS:

[0120] Figure 16 This mode of operation of the power converter 2 of the invention is illustrated in figure 3, in which the turn-off of one power switch 31 is delayed with respect to the other power switch 32, so that, once the current is close to or equal to zero, one power switch 32 is turned off, i.e. zero current switching ZCS, and in which the voltage or current in the power switch 31 can be sensed or calculated to implement the timing according to which, when the first power switch 31 goes to the off state and the second power switch 32 remains in the on state for a certain delay time t delay , the currents il and i2 start to decrease, after the first power switch 31 is turned off, until the current flowing through the second power switch 32 decreases to near zero, which is known in the literature as zero current switching ZCS. The delay time t delay between the turn-off of the first power switch 31 and the turn-off of the second power switch 32 is determined by sensing the current or by other means calculating the current in the second power switch 32.

[0121] In other words, the turn-off of one power switch is delayed with respect to the other power switch, so that, once the current is close to or equal to zero, the power switch is turned off, i.e. zero current switching ZCS, and in addition, the voltage or current of the power switch or equivalent can be sensed to implement this timing.

[0122] Zero current switching ZCS can be obtained in a simple way, just by turning off the primary power switch a little earlier than the secondary power switch. ​

[0123] In this short time, the current will stop flowing through the secondary power switch, so the secondary power switch will not turn off while high output current is passing through the secondary power switch, as Figure 15 shown.

[0124] When the logic control signal of S1 goes to the off state, the currents i1 and i2 start to decrease.

[0125] A certain delay time t delay after S1 turns off, the logic control signal of S2 remains in the on state until the current flowing through the power switch S2 decreases to around zero, which is called zero current switching (ZCS) in the literature.

[0126] The delay time t delay between S1 turning off and S2 turning off is determined by "sensing" the current or by other means "calculating" the current in S2.

[0127] The details of the results in the known topology achieved by the principle of the present application are described in detail below.

[0128] Table I shows typical power topology structures for the input port, FOM port , maximum voltage, and duty cycle range of a DC-DC converter:

[0129]

[0130] Table II shows typical power topology structures for the output port, FOM port , maximum voltage, and duty cycle range of a DC-DC converter:

[0131]

[0132] In one embodiment of the present application, the power converter 2 (DPX) of the present application further comprises the integration of a Buck converter 3 (see Figure 20 ), resulting in a three-port Buck-DPX 4 regulated DC-DC-DC converter as Figure 21 shown, where the magnetizing inductance of the DPX converter 2 is used as the inductance of the Buck converter 3, and the gain of the converter between the input and output ports is regulated by changing the duty cycle and / or switching frequency, where power can flow from at least one of the three ports to at least one of the remaining ports.

[0133] In an alternative embodiment, the three-port Buck-DPX 4 of Figure 22 is an adjustable AC-DC-DC converter.

[0134] Regarding Figure 21 and 22In the referenced embodiments of DPX2, the power switch 31 of DPX2 and the 33 of Buck converter 3 are configured to operate the three-port Buck-DPX 4 as a quasi-static DC-DC unit, wherein the first DC input port 201 receives a DC quasi-static voltage from a rectified high power factor AC voltage source, the second DC output port 202 is configured to act as an energy buffer and the third DC output port 203 is configured to have a tight DC voltage regulation.

[0135] Also with respect to the referenced embodiments of DPX2, Figure 21 and 22 the present invention proposes control means of the switching frequency, the duty cycle of the power switch 31 of DPX2 and the 33 of Buck converter 3 of the three-port Buck-DPX 4 to provide power flow according to three different operative power pathways:

[0136] A. Power flow from AC input port 201 through the first DC output port 202 and the second DC output port 203 (see Figure 23A ) ;

[0137] B. Power flow from AC input port 201 and the first DC output port 202 to the second DC output port 203 (see Figure 23B ) ;

[0138] C. Power flow from the first DC output port 202 to the second DC output port 203 (see Figure 23C ).

[0139] In further embodiments of the three-port Buck-DPX 4, the energy buffer comprises one or more capacitors configured to dynamically adjust to minimize indirect power having a voltage average related to the RMS value of the input voltage. Figure 24 AC line voltage is shown for the high voltage range (85-264 Vac) of the universal input voltage.

Claims

1. A power converter configured to connect a primary port comprising a DC power source and a secondary port comprising a DC load, the power converter (2) comprising: - a transformer or autotransformer connected to a plurality of nodes of the power converter; - at least one first power switch (31) between two nodes (31a; 31b) of the plurality of nodes, the at least one first power switch (31) having two power terminals, at least one first control terminal (101) and a first parallel capacitor; - and - at least one second power switch (32) between two other different nodes (32a; 32b) of the plurality of nodes, the at least one second power switch (32) having two power terminals, at least one second control terminal (102) and a second parallel capacitor; - the first power switch (31) being arranged on a primary side of the transformer or autotransformer and the second power switch (32) being arranged on a secondary side of the transformer or autotransformer, the first power switch (31) and the second power switch (32) being configured to connect the primary port to the secondary port through the transformer or autotransformer; - the at least first control terminal (101) and second control terminal (102) of the first power switch (31) and the second power switch (32) being different terminals or a single control terminal (100); and - the first power switch (31) and the second power switch (32) being further configured to be simultaneously operated under the effect of a logic control signal (100a) configured to provide an on state, wherein the first power switch (31) and the second power switch (32) are simultaneously in an on state or in an off state, connecting or disconnecting the transformer or autotransformer to the primary port and to the secondary port at the same time and forming a direct current power converter DPX; characterized in that: - the first power switch (31) and the second power switch (32) are simultaneously activated during a given time period, the on state time of the first power switch (31) and the second power switch (32) providing a direct current power path from the DC power source to the DC load through the transformer or autotransformer, the on duty cycle range of the first power switch (31) and the second power switch (32) being higher than 50% so that, for a given average converter output current, the RMS value of the current flowing through the first power switch (31) and the second power switch (32) is reduced, and - the on duty cycle of the first power switch (31) and the second power switch (32) is adjusted to maintain the peak voltage of the first power switch (31) and the second power switch (32) under given constraints. Thus, the magnetization of the transformer or autotransformer during said ON state is reset during said OFF state by resonance between the magnetizing inductance of said transformer or autotransformer and the first parallel capacitor connected across said first power switch (31) and the second parallel capacitor connected across said second power switch (32).

2. The power converter of claim 1, wherein, said first power switch (31) and said second power switch (32) are integrated in a single structure of three power terminals (11; 12; 13) and are connected together in a common node, providing a three power terminal power switch device (1), and a single control terminal (100) of said three power terminal power switch device (1) replaces said at least first control terminal (101) and second control terminal (102) of said first power switch (31) and said second power switch (32), wherein said logic control signal (100a) is applied to said single control terminal (100).

3. The power converter of claim 1, further comprising a control device configured to provide additional timing control, in advance or in delay of the application of said logic control signal (100a) to said first power switch (31) and said second power switch (32) during the power switch transition between said ON state and said OFF state, to reduce switching losses.

4. The power converter of claim 1, wherein, said first power switch (31) and said second power switch (32) are controlled switches implemented with transistors, or comprise at least one controlled switch implemented with a transistor and at least one uncontrolled switch implemented with a diode.

5. The power converter of claim 1, wherein, said ON state time of said first power switch (31) and said second power switch (32) is long enough to provide a current through the secondary winding of said transformer or autotransformer to reach a steady state, whereby the gain of the converter does not depend on the specific duration of said ON state time.

6. The power converter of claim 1, implemented using semiconductor technology selected from Si, GaN, SiC or by using a semiconductor comprising one or more components selected from a junction or heterojunction, a heterostructure, a piezoelectric structure, a metal-oxide-semiconductor field-effect transistor, an insulated-gate bipolar transistor, a bipolar junction transistor, a gate turn-off thyristor or a combination thereof.

7. The power converter of claim 1, wherein, said first power switch (31) and said second power switch (32) are respectively inserted in a winding of said transformer or autotransformer, or in a portion of said transformer or autotransformer.

8. The power converter of claim 1, comprising a control device adapted to configure the OFF state time of said first power switch (31) and said second power switch (32) by adjusting said logic control signal (100a) so that said first power switch (31) turns ON as soon as its own voltage equals zero.

9. The power converter of claim 1, comprising a control device adapted to configure the turn-on time of the first power switch (31) and the second power switch (32) by adjusting the logic control signal (100a) so that the turn-off of the second power switch (32) is delayed with respect to the first power switch (31) so that, once the current of the second power switch (32) itself is equal to zero, the second power switch (32) turns off or turns on with a certain delay to control the current delivered by the transformer.

10. The power converter of claim 9, wherein, The control device further comprises the leakage inductance of the transformer or autotransformer or an additional inductance in series configured to control the current delivered by the transformer by varying at least one of the duty cycle of the first power switch (31) and the second power switch (32), the delay and the switching frequency.

11. The power converter of claim 1, further comprising a Buck converter forming a three-port Buck-DPX (4) regulated DC-DC-DC converter, wherein, The magnetizing inductance of the DPX converter is used as the inductance of the Buck converter, wherein the gain of the DPX converter between the input port and the output port is adjusted by varying at least one of the duty cycle and the switching frequency, and wherein the power flows from at least one of the three ports to at least one of the remaining ports.

12. The power converter of claim 1, further comprising a Buck converter (3) comprising a power switch (33), forming a three-port Buck-DPX (4) regulated AC-DC-DC converter, wherein, The magnetizing inductance of the DPX converter is used as the inductance of the Buck converter, wherein the gain of the DPX converter between the input port and the output port is adjusted by varying at least one of the duty cycle and the switching frequency, and wherein the power flows from at least one of the three ports to at least one of the remaining ports.

13. The power converter of claim 12, wherein, The first power switch (31) of the DPX converter and the power switch (33) of the Buck converter (3) are configured to use the three-port Buck-DPX (4) as a quasi-static DC-DC unit, wherein the first DC input port (201) is configured to receive a DC quasi-static voltage from a rectified high power factor AC voltage, the second DC port (202) is configured to act as an energy buffer, and the third DC output port (203) is configured to have a strict DC voltage regulation.

14. The power converter of claim 12, wherein, The first power switch (31) of the DPX converter and the power switch (33) of the Buck converter (3) are configured to use the three-port Buck-DPX (4) as a quasi-static DC-DC unit, wherein the first DC input port (201) is configured to receive a DC quasi-static voltage from a rectified high power factor AC voltage, the second DC port (202) is configured to act as an energy buffer, the third DC output port (203) is configured to have a strict DC voltage regulation, and the power converter (2) comprises a control device of the switching frequency, the duty cycle of the first power switch (31) of the DPX converter and the power switch (33) of the Buck converter (3) to provide power flow according to three power operating paths: A. power from the first DC input port (201) is configured to flow through the second DC port (202) and the third DC output port (203); B. power from the first DC input port (201) and the second DC port (202) is configured to flow to the third DC output port (203); C. power from the second DC port (202) is configured to flow to the third DC output port (203).

15. The power converter of claim 14, wherein, The energy buffer comprises at least one capacitor configured to dynamically adjust to minimize indirect power having a voltage average related to the RMS value.

16. The power converter of claim 13, wherein, The DC power source or the DC load is a quasi-static DC voltage forming an AC voltage source or an AC load.

17. The power converter of claim 1, comprising a control device to adjust the peak voltage of the first power switch (31) and the second power switch (32) by active clamping, thereby dynamically regulating power conversion by adjusting the duty cycle, delay, and switching frequency of the first power switch (31) and the second power switch (32) under changes in input voltage, output voltage scaling, and positive / negative load current steps.

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