Active damping of soft-switching resonant converters

Abstract

Embodiments of the present disclosure relate to active damping of soft-switching resonant converters. A soft-switching resonant converter is disclosed. The converter includes a power switch operable to connect and disconnect a DC link rail node with an output node. A resonant capacitor is coupled with the power switch. An auxiliary arm is coupled with a DC link midpoint node and the output node. An active damper is coupled in series with the resonant capacitor and the output node, and the active damper is controllable to provide a first resistance of the active damper in a first state and a second resistance of the active damper in a second state, the first resistance having a lower magnitude than the second resistance. A driver controls a damper switch to provide the first resistance during soft-switching operation of the power switch and to provide the second resistance after soft-switching operation of the power switch.

Description

Technical Field

[0001] The present application relates to soft-switching resonant converters, such as auxiliary resonant commutated pole inverters (ARCPI), and more particularly, but not exclusively, to damping current and voltage ringing in the commutation loop of such converters. Background Art

[0002] Soft switching converters (such as ARCPI) offer advantages over hard switching converters including low switching losses and improved suitability for high frequency switching applications. However, such converters face a number of difficulties, such as undesirable voltage or current oscillations, sometimes referred to as voltage and current ringing. Many efforts have been made to mitigate voltage and current circuit ringing. Some approaches seek to utilize small resonant capacitors with inherently high damping factors and ringing frequencies. However, for applications where large resonant capacitors are required and the commutation loop inductance cannot be minimized, this approach is insufficient. In such applications, the voltage and current ringing may be worse due to the lower ringing frequency and lower damping factor. In addition, additional damping is required to operate properly at high switching frequencies. There remains a large unmet need for the unique apparatus, methods, and systems disclosed herein. Summary of the Invention

[0003] In order to clearly, concisely, and accurately describe the exemplary embodiments of the present disclosure, the manner and process of making and using the same, and to enable the practice, making, and use of the exemplary embodiments of the present disclosure, reference will now be made to certain exemplary embodiments, including those shown in the accompanying drawings, and specific language will be used to describe these exemplary embodiments. However, it should be understood that no limitation is created thereby as to the scope of the present invention, and that the present invention includes and protects such changes, modifications, and other applications of the exemplary embodiments as will occur to those skilled in the art.

[0004] One exemplary embodiment is a unique soft-switching resonant converter including an active damper. Another exemplary embodiment is a unique method of operating a soft-switching resonant converter including an active damper. Another exemplary embodiment is a unique system including a soft-switching resonant converter including an active damper. Further embodiments, aspects, objects, features, advantages, aspects, and benefits will become apparent from the following description and accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0005] Figure 1 is a schematic circuit diagram depicting certain aspects of a soft-switching resonant converter circuit arrangement according to an example embodiment.

[0006] Figure 2 is a signal timing diagram depicting certain aspects of the operation of a soft-switching resonant converter circuit arrangement according to an example embodiment.

[0007] Figure 3A It is a depiction Figure 1 Schematic circuit diagram of certain aspects of the active damping operating regime of a soft-switching resonant converter circuit arrangement.

[0008] Figure 3B It is a depiction Figure 1 Schematic circuit diagram of certain aspects of another active damping operating state of a soft-switching resonant converter circuit arrangement.

[0009] Figure 4 is a schematic circuit diagram depicting certain aspects of a soft-switching resonant converter circuit arrangement according to another example embodiment.

[0010] Figure 5 is a schematic circuit diagram depicting certain aspects of example control and drive circuitry.

[0011] Figure 6 and Figure 7 is a schematic circuit diagram depicting certain aspects of an example power supply circuit arrangement.

[0012] Figures 8 to 14 are schematic circuit diagrams depicting certain aspects of several example bidirectional switches. DETAILED DESCRIPTION

[0013] refer to Figure 1 , illustrates an example embodiment of a soft-switching resonant converter circuit arrangement 100 (also referred to herein as circuit arrangement 100). In the illustrated embodiment, circuit arrangement 100 is configured as an auxiliary resonant commutated pole (ARCP) inverter (also referred to herein as ARCPI). It should be understood that in other embodiments, circuit arrangement 100 can be configured as various other types of soft-switching resonant converters, including, for example, a resonant load inverter, a resonant link inverter, a resonant pole inverter, or other types of soft-switching resonant converters. It should be understood that ARCP converters include various converter types that utilize an auxiliary pole to achieve soft switching and are not limited to the illustrated embodiment. Other embodiments include poles with various structures and connections. Furthermore, the present disclosure contemplates various architectures and configurations of soft-switching resonant converters in which capacitors (sometimes also referred to as resonant capacitors or snubber capacitors) are arranged in parallel with semiconductor switches, wherein the disclosed active damping circuit arrangement architecture can be applied to the commutation loop between the switch and the capacitor. Therefore, it should be understood that the description of the illustrated aspects of circuit arrangement 100 is applicable to related aspects of other such converters as would be understood by those skilled in the art having the benefit of this disclosure.

[0014] Circuit arrangement 100 includes a DC link 110 including a first DC link capacitor 111 coupled to a first DC link rail 113 and a DC link midpoint 115, and a second DC link capacitor 112 coupled to a second DC link rail 114 and the DC link midpoint 115. During operation, first DC link rail 113 is at a first voltage, second DC link rail 114 is at a second voltage lower than the first DC voltage, and DC link midpoint 115 is at a midpoint voltage. First DC link rail 113 includes an equivalent series inductance (ESL) 103, which is an inherent inductance or parasitic inductance of first DC link rail 113 rather than a discrete inductor. Second DC link rail 114 includes ESL 104, which is an inherent inductance or parasitic inductance of second DC link rail 114 rather than a discrete inductor.

[0015] It should be understood that the DC link 110 can be provided in a variety of forms and can have a variety of voltages and other properties. Certain embodiments include low voltage (LV) applications, where the voltage difference between the positive DC link rail and the negative DC link rail (e.g., DC link rail 113 and DC link rail 114) can be between 50 VDC and 1000 VDC. In other embodiments, higher voltage levels in the range of several kV are contemplated. Other embodiments contemplate a variety of other voltage magnitudes and voltage differences. It should also be understood that the voltage difference between the positive DC link rail and the negative DC link rail (e.g., DC link rail 113 and DC link rail 114) is flexible, depending on how the DC link 110 is fed. For example, some embodiments may use a front-end isolation transformer and rectifier connected to the DC link, where the positive and negative rails are floating and the differential voltage is typically in the range of 50 V to 1500 V, but in principle other voltages outside this range are also possible. In other embodiments, the positive rail, midpoint, or negative rail may be grounded to earth ground. Preferably, the positive and negative rails (e.g., DC link rail 113 and DC link rail 114) are balanced. For example, if DC link midpoint 115 is at 0 VDC, DC link rail 113 will be at a positive voltage (e.g., in the range of +25 VDC to +500 VDC, in the range of +150 VDC to +400 VDC, or in another positive voltage range) and DC link rail 114 will be at a negative voltage corresponding to the positive voltage (e.g., in the range of -25 VDC to -500 VDC, in the range of -150 VDC to -400 VDC, or in another negative voltage range corresponding to another positive voltage range). It should be understood that the foregoing examples are only some of the many voltage magnitudes and polarities that may exist in or be associated with the operation of DC link 110. It should also be understood that the foregoing example voltage magnitudes may be subject to fluctuations, error margins, tolerances, and other variations and may not be strictly fixed to the exact example magnitudes described. It should also be understood that the term "bus" may be used instead of the term "link", so that, for example, reference to a DC link is understood to include a DC bus and vice versa.

[0016] The circuit arrangement 100 includes a power section 120 including a first power switch 121 coupled to the first DC link rail 113 at a first DC link rail node 117 and to an AC load (not shown) at an output node 125, and a second power switch 122 coupled in series with the second DC link rail 114, the second DC link rail node 118, and the output node 125. The first power switch 121 is operable to respond to a signal from the control and driver circuit arrangement ( Figure 111. The first power switch 121 includes an ESL (equivalent series inductance) 123, which is an inherent or parasitic inductance of the first power switch 121 and the connection to the DC link rail 113. The ESL 123 corresponds to a portion of the total commutation loop inductance (rather than a discrete inductor). The second power switch 122 includes an ESL 124, which is an inherent or parasitic inductance of the second power switch 122 and the connection to the DC link rail 114 (rather than a discrete inductor).

[0017] When the first power switch 121 is closed (eg, controlled to be in an on or conducting state), the first switch current i S1 The second switching current i may flow between the DC link rail node 117 and the output node 125. Similarly, when the second power switch 122 is closed (eg, controlled to be in an on or conducting state), the second switching current i S2 The first switching current i may flow between the output node 125 and the DC link rail node 118. On the other hand, when the first power switch 121 is turned off (eg, controlled to be in an off or non-conductive state), the first switching current i S1 will not flow between the DC link rail node 117 and the output node 125 in the switching forward direction (although current can flow in the switching reverse direction through the anti-parallel diode of the first power switch 121). Similarly, when the second power switch 122 is open (e.g., controlled to an off or non-conducting state), the second switch current i S2 Current will not flow between DC link rail node 118 and output node 125 in the switched forward direction (although current can flow in the switched reverse direction through the anti-parallel diode of second power switch 122). Therefore, by opening and closing first power switch 121 and second power switch 122, the load voltage at output node 125 will be controlled to either the voltage from DC link rail 113 or the voltage from DC link rail 114.

[0018] The first power switch 121 and the second power switch 122 can be provided in a variety of forms, including, for example, semiconductor switching devices such as insulated gate bipolar transistors (IGBTs), metal oxide semiconductor field effect transistors (MOSFETs), silicon carbide metal oxide semiconductor field effect transistors (SiC MOSFETs), SiC junction gate field effect transistors (SiC JFETs), gallium nitride high electron mobility transistors (GaN HEMTs), gallium nitride metal oxide semiconductor field effect transistors (GaN MOSFETs), or other types of power switching devices understood by those skilled in the art with the benefit of this disclosure. In some forms, the first power switch 121 and the second power switch 122 are provided as IGBTs having a blocking voltage rating greater than VDC, for example, 1.2 kV or in the range of 1 kV or greater.

[0019] Circuit arrangement 100 includes a commutation section 130 including a first resonant capacitor 131 connected in parallel with a first power switch 121 to provide a first commutation loop 133, and a second resonant capacitor 132 connected in parallel with a second power switch 122 to provide a second commutation loop 134. The first resonant capacitor 131 includes an ESL 135 as an inherent inductance or parasitic inductance of the first resonant capacitor 131. The second resonant capacitor 132 includes an ESL 136 as an inherent inductance or parasitic inductance of the first resonant capacitor 131.

[0020] The circuit arrangement 100 includes an auxiliary arm 140 coupled in series with a DC link midpoint node 115 and an output node 125. The auxiliary arm 140 includes an auxiliary switch 142 and an inductor 145. The auxiliary switch 142 is operable to connect and disconnect the DC link midpoint node 115 from the output node 125 in coordination with the operation of the power switch 121 and the second power switch 122 to provide soft switching of the first power switch 121 and the second power switch 122. In the illustrated embodiment, the auxiliary switch 142 is a bidirectional switch that includes two switching devices 142a, 142b in an anti-series configuration or connected in series with opposite polarity. The switching devices 142a, 142b may be IGBTs, MOSFETs, or other types of power switching devices as will be understood by those skilled in the art having the benefit of this disclosure. In other embodiments, the auxiliary switch 142 may be a single device bidirectional switch, such as a bidirectional gallium nitride (GaN) switching device or various other bidirectional controllable switch topologies, including, for example, those described further below. Figures 8 to 11 The device shown.

[0021] When the auxiliary switch 142 is closed (eg, controlled to be in an on or conducting state), the auxiliary current i auxmay flow between the midpoint node 115 and the output node 125. On the other hand, when the auxiliary switch 142 is open (e.g., controlled to an off or non-conductive state), no auxiliary current i aux may flow between the midpoint node 115 and the output node 125. Similarly, when the second power switch 122 is open (e.g., controlled to an off or non-conductive state), no second switch current i S2 may flow between the output node 125 and the DC link rail node 118.

[0022] The circuit arrangement 100 includes an active damper 150 coupled between the midpoint of the capacitors 131-132 and the output node 125, and including a damper switch controllable to provide a first resistance of the active damper in a first switch state and a second resistance of the active damper in a second switch state, the first resistance having a lower magnitude than the second resistance. The active damper can be provided in a variety of forms. In the illustrated embodiment, the active damper 150 includes a bidirectional damper switch 151 (sometimes referred to herein as the damper switch 151 or the bidirectional switch 151) including a first switch device 151a and a second switch device 151b arranged in an anti-series relationship, and a damping resistor 152 disposed in parallel with the first and second switch devices 151a-151b. The first and second switch devices 151a-151b can be MOSFET devices having a blocking voltage rating in the range of 100-200V or approximately 20% of the DC bus voltage Vdc. It will be appreciated that the use of such devices provides significantly lower on-state losses relative to switch devices having higher voltage ratings, such as the voltage ratings of the first and second power switches 121-122, which can be, for example, 1200V. Figure 1 The illustrated embodiment, the active damper 150 includes a bidirectional damper switch 151 (sometimes referred to herein as the damper switch 151 or the bidirectional switch 151) including a first switch device 151a and a second switch device 151b arranged in an anti-series relationship, and a damping resistor 152 disposed in parallel with the first and second switch devices 151a-151b. The first and second switch devices 151a-151b can be MOSFET devices having a blocking voltage rating in the range of 100-200V or approximately 20% of the DC bus voltage Vdc. It will be appreciated that the use of such devices provides significantly lower on-state losses relative to switch devices having higher voltage ratings, such as the voltage ratings of the first and second power switches 121-122, which can be, for example, 1200V.

[0023] When the first and second switch devices are closed (e.g., controlled to an on or conductive state), the active damper 150 provides a bidirectional first resistance to the resonant capacitor current i Cr , which can be zero or near zero, e.g., the inherent resistance of the first and second switch devices 151a-151b in the on or conductive state. When the first and second switch devices 151a-151b are open (e.g., controlled to an off or non-conductive state), the active damper 150 provides a bidirectional second resistance to the resonant capacitor current i Cr , depending on the value of the damping resistor 152. In certain forms, the second resistance provided by the damping resistor 152 can be, for example, 0.1-0.5 ohms or other values, depending on the rated current of the converter.

[0024] In other embodiments, the active damper 150 may be provided in a variety of other forms. For example, in some forms, rather than including a first switching device 151a and a second switching device 151b, the damping switch 151 may include a single bidirectional switching device, such as a gallium nitride (GaN) transistor, arranged in parallel with a damping resistor 152. In some forms, instead of the damping switch 151 and the damping resistor 152, a three-state device may be controlled to provide a first resistance in a first state and may be used to provide a second resistance in a second state. It will be understood that the three-state device may include a bidirectional switch, such as the bidirectional switch 151 without the resistor 152, where the bidirectional switch is controlled in a three-state manner by a gate voltage / current, as opposed to being conventionally on or off. The third state corresponds to an intermediate desired resistance value; higher than the on state and much lower than the off state. It should also be understood that the foregoing examples are only a few examples of active dampers including a damper switch that can be controlled to provide a first resistance of the active damper in a first switching state and a second resistance of the active damper in a second switching state, the first resistance having a lower magnitude than the second resistance, and that the active damper 150 also contemplates other forms and variations that would be understood by those skilled in the art having the benefit of this disclosure.

[0025] refer to Figures 8 to 11 , shows several other examples of bidirectional switches that can be used in place of the bidirectional damping switch 151 of the active damper 150 , in place of the auxiliary switch 142 of the auxiliary arm 140 , or in place of other switches according to the present disclosure.

[0026] Figure 8 A bidirectional switch 251 is shown as an example of a gallium nitride (GaN)-based switch. The bidirectional switch 251 is a four-terminal GaN HMET device including first and second switch terminal nodes S1, S2, and first and second gate terminal nodes G1, G2. The source of the GaN switch device portion 202 is coupled to the switch terminal node S1, the source of the GaN switch device portion 204 is coupled to the switch terminal node S2, and the drains of the GaN switch device portions 202 and 204 are coupled to each other and can share the same drain region inside the GaN device to have a lower on-resistance. The first and second gate terminal nodes G1 and G2 are connected to the corresponding first driver voltage V g1 and the second driver voltage V g2 coupling.

[0027] Figure 9A bidirectional switch 351 is shown, which includes four diodes 301, 303, 305, and 307 and a single IGBT switching device 302. The anode of diode 301 and the cathode of diode 305 are coupled to a first switching terminal node. The anode of diode 303 and the cathode of diode 307 are coupled to a second switching terminal node. The cathode of diode 301, the cathode of diode 303, and the collector of IGBT switching device 302 are coupled to a third node. The anode of diode 305, the anode of diode 307, and the emitter of IGBT switching device 302 are coupled to a fourth node.

[0028] Figure 10 A bidirectional switch 451 is shown, which includes IGBT switching devices 402 and 404 and freewheeling diodes 401 and 403. The anode of diode 401 and the emitter of IGBT switching device 404 are coupled to a first switch terminal node. The anode of diode 403 and the emitter of IGBT switching device 402 are coupled to a second switch terminal node. The cathodes of diodes 401 and 403 and the collectors of IGBT switching devices 402 and 404 are coupled to a common center node.

[0029] Figure 11 A bidirectional switch 551 is shown that includes two reverse-blocking IGBT switching devices 502 and 504 arranged in an anti-parallel configuration. The emitter of the reverse-blocking IGBT switching device 502 and the collector of the reverse-blocking IGBT switching device 504 are coupled to a first switching terminal node. The collector of the reverse-blocking IGBT switching device 502 and the emitter of the reverse-blocking IGBT switching device 504 are coupled to a second switching terminal node.

[0030] Figure 12 A common-emitter version of a bidirectional switch 651 is shown, comprising reverse-blocking IGBT switching devices 602 and 604 and diodes 601 and 603. The cathode of diode 601 and the collector of IGBT switching device 604 are coupled to a first switch terminal node. The cathode of diode 603 and the collector of IGBT switching device 602 are coupled to a second switch terminal node. The anodes of diodes 601 and 603 and the emitters of IGBT switching devices 602 and 604 are coupled to a common center node. It is also contemplated that a common-source version of the bidirectional switch may be used, similar to the common-emitter version of bidirectional switch 651, wherein the source of a MOSFET or other FET device is coupled in a manner corresponding to the emitter of the IGBT switching devices 602 and 604, and the drain of the MOSFET or other FET device is coupled in a manner corresponding to the collector of the IGBT switching devices 602 and 604.

[0031] Figure 13Another form of a bidirectional switch 751 is shown, comprising BJT switching devices 702 and 704 and diodes 701 and 703. The cathode of diode 701 and the collector of BJT switching device 704 are coupled to a first switch terminal node. The cathode of diode 703 and the collector of BJT switching device 702 are coupled to a second switch terminal node. Diode 701 is connected in series with BJT switching device 702, wherein the anode of diode 701 is coupled to the emitter of BJT switching device 702. Diode 703 is connected in series with BJT switching device 704, wherein the anode of diode 703 is coupled to the emitter of BJT switching device 704.

[0032] Figure 14 Additional forms of bidirectional switches are shown. Bidirectional switch 851 includes Si MOSFETs 853, 855 arranged in series in a common drain configuration, wherein the drains of Si MOSFETs 853, 855 are coupled at a common central node. Bidirectional switch 951 includes Si MOSFETs 953, 955 arranged in series in a common source configuration, wherein the sources of Si MOSFETs 953, 955 are coupled at a common central node. It should be understood that Si MOSFETs 853, 855, 953, 955 do not utilize parasitic diodes or body diodes (e.g., similar to external diodes for IGBTs) to conduct bidirectional current, but instead use their respective channels to conduct bidirectional current. This form may be preferred to provide lower losses because diodes have greater losses than Si MOSFET channels. Bidirectional switches (such as bidirectional switches 851, 951) provide lower losses at lower voltage ratings (e.g., at 20% of the voltage rating of the main IGBT).

[0033] refer to Figure 2 , shows a signal timing diagram 200 depicting certain aspects of the operation of a soft switching resonant converter circuit device according to an example embodiment. The signal timing diagram 200 shows several signal groups, including signal group 210, signal group 220, signal group 230, signal group 240, and signal group 250. Signal group 210 shows the output voltage signal v o , the first power switch current signal i s1 , and the second power switch current signal i s2 . Output voltage signal v o is the voltage at an output node (such as output node 125 of circuit arrangement 100) relative to the DC link capacitor midpoint 115. The first power switch current signal i s1 is the current through the first power switch (such as the power switch 121 of the circuit arrangement 100). The second power switch current signal i s2is the current through a second power switch (such as power switch 122 of circuit arrangement 100 ).

[0034] Signal group 220 shows the output current signal i o , resonant capacitor current signal i Cr , and auxiliary current signal i aux . Output current signal i o The resonant capacitor current signal i is the current flowing from an output node (such as output node 125 of circuit arrangement 100) to a load connected to the output node. Cr is the current flowing to the resonant capacitor (such as the resonant capacitor 131 or the resonant capacitor 132 of the circuit device 100). aux is the current flowing through the auxiliary arm of the converter, such as the auxiliary arm 140 of the circuit arrangement 100 .

[0035] Signal group 230 shows a first power switch drive logic signal G1 and a second power switch drive logic signal G2. The first power switch drive logic signal G1 is provided and used to control the operating state of a first power switch (such as the first power switch 121 of the circuit device 100). When the first power switch drive logic signal G1 is at a logic high value ("1"), the first power switch is turned on (i.e., closed), and when the first power switch drive logic signal G1 is at a logic low value ("0"), the first power switch is turned off (i.e., opened). The second power switch drive logic signal G2 is provided and used to control the operating state of a second power switch. When the second power switch drive logic signal G2 is at a logic high value ("1"), the second power switch is turned on (i.e., closed), and when the second power switch drive logic signal G2 is at a logic low value ("0"), the second power switch is turned off (i.e., opened).

[0036] Signal group 240 shows the first auxiliary switch driving logic signal G a1 and the second auxiliary switch driving logic signal G a2 The first auxiliary switch drives the logic signal G a1 is provided and used to control the operating state of a first auxiliary switch (such as the switching device 142a of the circuit arrangement 100). When the first auxiliary switch drives the logic signal G a1 When the first auxiliary switch is at a logic high value (“1”), the first auxiliary switch is turned on (ie, closed), and when the first auxiliary switch drives the logic signal G a1 When the first auxiliary switch is at a logic low value ("0"), the first auxiliary switch is turned off (ie, open). The second auxiliary switch drives the logic signal G a2 is provided and used to control the operating state of the second auxiliary switch (such as the switching device 142b of the circuit arrangement 100). When the second auxiliary switch drives the logic signal G a2When the second auxiliary switch is at a logic high value (“1”), the second auxiliary switch is turned on (ie, closed), and when the second auxiliary switch drives the logic signal G a2 When at a logic low value ("0"), the second auxiliary switch is off (ie, open).

[0037] Signal group 250 shows the active damper drive logic signal G d , the active damper drives the logic signal G d is provided and used to control the operating state of an active damper switch (such as the active damper switch 150 or more specifically the first switching device 151a and the second switching device 151b of the circuit arrangement 100). d When at a logic high value (“1”), the active damper switch is on (ie, closed), and when the active damper drive logic signal G d When at a logic low value ("0"), the active damper is off (ie, disconnected). It should be understood that the signals G1, G2, G a1 , G a2 and G d It may also be considered and referred to as a gate signal in embodiments where its corresponding switch includes a semiconductor device including a gate input (eg, an IGBT, MOSFET, other field effect transistor, or other semiconductor device including a gate).

[0038] Signal groups 230 and 240 are configured to control the power switches and auxiliary switches described above by providing the current and voltage signals shown in signal groups 210 and 220 to provide zero-voltage soft switching of first and second power switches (such as first power switch 211 and second power switch 212 of circuit arrangement 100). More details regarding the operation of the power switches and auxiliary switches of an example soft-switching resonant converter can be found in U.S. Patent No. 7,411,797, the disclosure of which is incorporated herein by reference.

[0039] The signal group 250 is configured to control a damper switch (such as the damper switch 151 of the circuit arrangement 100) to provide active damping of voltage and current ringing following soft-switching operation of the first power switch and the second power switch. From time t0 to time t1, the damper switch can be controlled to be on (i.e., closed) or off (i.e., open), as either state will allow for the desired operation of the soft-switching resonant converter circuit arrangement.

[0040] At time t lThe damper switch is controlled to be on (i.e., closed) to provide a relatively low magnitude resistance that allows soft-switching operation to occur without interfering with the active damper circuit device beginning at time tl and continuing to time t2. For example, during this time period, the first power switch (such as power switch 121 of circuit device 100) can be turned off (i.e., opened) at substantially zero voltage, the second power switch 122 (such as power switch 122 of circuit device 100) can be turned on (i.e., closed) at substantially zero voltage, and the resistance of the damper switch, if any, will have minimal impact on this soft-switching operation and the relatively high resonant current peaks used to provide such soft-switching. Because it is desirable, although not necessary, for the damper switch to be on (i.e., closed) throughout the time between times tl and t2, the precise timing of the damper drive logic signal G d can be selected to ensure that the damper switch is on (i.e., closed) at or before time tl.

[0041] Beginning at time t2 and continuing to time t3, the damper switch is controlled to be off (i.e., opened) to provide a relatively high magnitude resistance that effectively damps the current and voltage ringing in the soft-switching resonant converter circuit device. For example, referring to Figure 3A , a state of operation of circuit device 100 is shown between times t2 and t3 in which power switch 121 is controlled to be off (i.e., opened), power switch 122 is controlled to be on (i.e., closed), and active damper 150 is controlled to provide the resistance of damping resistor 152 to attenuate the current and voltage ringing in first loop 171 and second loop 172. As shown in Figure 3A , first loop 171 includes second power switch 122, active damper 150, and second commutation loop 134 (including second resonant capacitor 132). In addition, second loop 172 includes first DC link rail 113, a portion of first commutation loop 133 including first resonant capacitor 131, active damper 150, second power switch 122, second DC link rail 114, and DC link capacitors 111, 112.

[0042] From time t3 to time t4, the damper switch can be controlled to be on (i.e., closed) or off (i.e., open), as either state will allow the desired operation of the soft-switching resonant converter circuit device. Starting at time t4 and continuing until time t5, when the commutating resonant current flows into the resonant capacitors 131 and 132, the damper switch is controlled to be on (i.e., closed) to provide a relatively low resistance of sufficient magnitude to allow soft switching operation to occur without interfering with the active damper circuit device. For example, during this time period, the first power switch (such as the power switch 121 of the circuit device 100) can be turned on (i.e., closed) at substantially zero voltage, the second power switch 122 (such as the power switch 122 of the circuit device 100) can be turned off (i.e., open) at substantially zero voltage, and the resistance of the damper switch will provide minimal, if any, impact on the soft switching operation and the relatively high resonant current peak used to provide such soft switching. Because it is desired that the damper switch be on (ie, closed) throughout the time between time t4 and t5, the damper drive logic signal G may be selected to be d The precise timing of the damper switch is to ensure that the damper switch is turned on (ie, closed) at or before time t4.

[0043] Beginning at time t5 and continuing until time t6, the damper switch is controlled to be off (i.e., open) to provide a relatively high resistance of sufficient magnitude to damp the current and voltage ringing in the soft-switching resonant converter circuit arrangement. This damping operation is Figure 3B and similar to Figure 3A The operating state shown in Figure 3A The operating state shown in FIG is opposite, wherein the power switch 121 is controlled to be on (i.e., closed), the power switch 121 is controlled to be off (i.e., open), and the active damper 150 is controlled to provide the resistance of the damping resistor 152 to attenuate the current and voltage ringing in the third loop 171 ′ and the fourth loop 172 ′, the third loop 171 ′ being similar to but opposite to the first loop 171 and the fourth loop 172 ′ being similar to but opposite to the loop 172. Therefore, compared Figure 3A and Figure 3B, it can be seen that the third loop 171′ is on the side of the circuit arrangement 100 opposite the first loop 171 and includes the first power switch 121, the active damper 150, and the first commutation loop 133 (including the first resonant capacitor 131). Similarly, the fourth loop 172′ is on the side of the circuit arrangement 100 opposite the second loop 172 and includes: the second DC link rail 114, the first power switch 121, the active damper 150, a portion of the second commutation loop 134 including the second resonant capacitor 132, the first DC link rail 113, and the DC link capacitors 111 and 112. Starting at time t6 (which can be considered a new time t0), the previous description of the signal timing diagram 200 is repeated.

[0044] refer to Figure 4 , a schematic diagram depicting certain aspects of an example circuit device 101 configured as an additional example of ARCPI is shown. In other embodiments, the circuit device 101 can be configured to include various other types of soft-switching resonant converters of the examples described in conjunction with the circuit device 100. The circuit device 101 includes a plurality of elements that are the same as or substantially similar to corresponding elements of the circuit device 100. Such elements are used in conjunction with the circuit device 100 and Figure 1 The same reference numerals are used to designate these elements, and it should be understood that the preceding description of these elements in conjunction with circuit arrangement 100 applies to corresponding elements of circuit arrangement 101. Circuit arrangement 101 also differs from circuit arrangement 100 in certain respects. For example, the commutation portion of circuit arrangement 101 includes a single resonant capacitor 232 coupled in parallel with second power switch 122 to provide a commutation loop 234. Resonant capacitor 232 includes an ESL 236, which is the inherent inductance or parasitic inductance of resonant capacitor 232, rather than a discrete inductor. Resonant capacitor 232 is configured to provide a soft switching function for both power switch 121 and power switch 122, and is therefore sized to provide twice the capacitance of either resonant capacitor 131 or resonant capacitor 132 alone.

[0045] refer to Figure 5 , shows an example embodiment of a driver circuit arrangement 500. In the shown example of the driver circuit arrangement 500, the damping switch S d (eg, the gate signal (G Sd ) from the gate signal (G 1 / 2 ) and auxiliary switch G a1 or G a2 The gating signal (G a1 / 2 ) is generated. Due to the damping switch S dThe control logic 510 can be used to perform a logical NOT operation (G1 NOR G2) on the gate control signals for the power switches to generate the gate driver control signal G provided to the damper gate driver 520, as long as the first and second power switches (such as the power switches 121 and 122 of the circuit arrangement 100) are turned on during the dead time or steady state time or when the commutation resonant current flows through the resonant capacitors 133 and 134. d In response to this signal, the gate driver 520 generates the damper switch gate drive signal G Sd , the damper switch gate drive signal G Sd is provided to drive the damping switch S d The gate of the damper switch (eg, the gate of the switching devices 151a, 151b of the circuit arrangement 100). The gate driver 520 also receives the damper switch supply voltage V cc,Sd and the supply voltage S Sd , the gate driver 520 generates the damper switch gate drive signal G Sd When using the damper switch power supply voltage V cc,Sd and the supply voltage S Sd It should be understood that for practical implementation, some delay circuitry may be required to align the switching timings.

[0046] The driver circuit device 500 is an example of a damper driver that is operably coupled to a damper switch and configured to control the damper switch such that during a soft switching operation of the power switch, the damper switch is in a first state, and once the soft switching operation of the power switch is completed, the damper is in a second state. It should be understood that in other embodiments, the control and driver circuit device 500 may be provided in a variety of different forms. The control logic 510 may be provided in a variety of forms, including, for example, a microprocessor or microcontroller-based form that executes instructions stored in a non-transitory memory medium, a component of a logic gate circuit device, a component of an analog circuit device, a field programmable gate array (FPGA), and combinations of these and / or other forms of control logic. In some forms, the control logic 510 may utilize other logic to identify the dead time or steady state time of the power switch. In some forms, the control logic 510 may utilize sensed or measured current and voltage signals associated with the power switch (e.g., power switches 121, 122), the load current and voltage (e.g., current i o and voltage v o), and / or currents and voltages associated with other elements or nodes of the soft-switching resonant converter from which the operation of the power switch can be determined or identified. In this form, a field programmable gate array (FPGA) can be used to process the sensed or measured current and voltage values. It should also be understood that embodiments utilizing a tri-state device as the damping switch will include additional control circuitry depending on the topology of the given tri-state device.

[0047] refer to Figure 6 , shows an example embodiment of an isolated gate driver power supply 600. In the illustrated embodiment, the power supply (PS) 600 includes a voltage source 601 that is specific and dedicated to powering a damper switch of a soft-switching resonant converter circuit arrangement (such as the damper switch 150 of the circuit arrangement 100). The power supply 100 also includes an isolation circuit arrangement 610 that may include one or more transformers or other core and winding assemblies configured to transfer power from the voltage source 601 in an isolated manner without using a conductive current path between the other illustrated circuit arrangements of the circuit arrangement 600 and the voltage source 601. The power supply 600 also includes a supply capacitor 620, a damper switch supply voltage (V cc,Sd ) output and power supply or reference voltage (S Sd It should be understood that the power supply 600 is isolated from one or more additional power supplies used to drive the power switches (such as power switches 121 , 122 ) and / or the auxiliary switches (such as auxiliary switch 142 ).

[0048] refer to Figure 7 , shows an example embodiment of a non-isolated gate driver power supply 700. In the illustrated embodiment, the power supply 700 draws power from a voltage source 701 that is configured to supply power to a power switch, such as one or more of the power switches 121, 122 of the circuit arrangement 100. Because the damper switch and the power switch do not always have a common power supply, additional circuit arrangements can be utilized to accommodate the use of a common voltage source between these switches. During operating periods other than ringing damping (e.g., all periods other than the period between time t2 and t3 or between time t5 and t6 of the signal timing diagram 200), the damping switch S d The source S Sd and the source S of the power switch S1 S1 have commonality, and the two sources have the same potential because they are connected by the damping switch S d or damping resistor R dThus, power can be delivered from the power supply for the power switch driver to the damping switch driver. During the ringing damping period (e.g., the period between time t2 and t3 and between time t5 and t6 of the signal timing diagram 200), the damping resistor R d The voltage drop across the damping switch actuator S Sd The potential of the power switch driver S S1 To limit current surges, the positive rails of the two power supplies are connected through resistor R1 of resistor 716, and Zener diode 718 is used to clamp any surge voltage above the designed drive voltage.

[0049] Aspects of the example embodiments disclosed herein will now be further described. A first example embodiment is a power converter comprising: a power switch coupled to a DC link rail node and an output node, the power switch operable to connect and disconnect the DC link rail node from the output node; a resonant capacitor coupled to the power switch; an active damper coupled in series with the resonant capacitor and the output node, the active damper comprising a damper switch controllable to provide a first resistance of the active damper in a first state and a second resistance of the active damper in a second switching state, the first resistance having a lower magnitude than the second resistance; and a damper driver operably coupled to the damper switch, the damper driver being configured to control the damper switch such that the damper switch is in the first state during soft switching operation of the power switch and is in the second state after the soft switching operation of the power switch is completed.

[0050] A second example embodiment includes the features of the first example embodiment, wherein the damper driver is configured to control the damper switch such that the damper switch is in the first state before the soft switching operation of the power switch is initiated.

[0051] A third example embodiment includes the features of the first or second example embodiment, wherein the damper driver is configured to control the damper switch such that the damper switch is switched to the first state simultaneously with the start of the soft switching operation of the power switch.

[0052] The fourth example embodiment includes the features of any one of the first to third example embodiments, wherein the damper driver is configured to control the damper switch so that the damper switch switches to the second state simultaneously with the end of the soft switching operation of the power switch.

[0053] A fifth example embodiment includes the features of any one of the first to fourth example embodiments, wherein a resonant capacitor is coupled in parallel with the power switch.

[0054] A sixth example embodiment includes the features of any one of the first to fifth example embodiments, wherein the damper switch includes a bidirectional switching device.

[0055] A seventh example embodiment includes the features of the sixth example embodiment, wherein the bidirectional switch device includes a first silicon metal oxide semiconductor field effect transistor (Si MOSFET) and a second Si MOSFET coupled in series with opposite polarities.

[0056] The eighth example embodiment includes the features of any one of the first to seventh example embodiments, and includes an auxiliary arm coupled in series with the DC link midpoint node and the output node, the auxiliary arm including an auxiliary switch and an inductor, the auxiliary switch being operable to connect and disconnect the DC link midpoint node from the output node in coordination with the operation of the power switch to provide soft switching of the power switch.

[0057] A ninth example embodiment includes the features of the eighth example embodiment and comprises: a second power switch coupled to the second DC link rail node and the output node, the second power switch being operable to connect and disconnect the second DC link rail node from the output node; and a second resonant capacitor coupled to the second power switch.

[0058] A tenth example embodiment includes the features of any one of the first to ninth example embodiments, wherein the damper driver is configured to control the damper switch in response to a gate control signal for the power switch.

[0059] An eleventh example embodiment includes the features of the tenth example embodiment, wherein the damper driver is configured to control the damper switch in response to the sensed current value and voltage value.

[0060] The twelfth example embodiment includes the features of any one of the first to eleventh example embodiments, wherein the active damper is configured to suppress ringing in the first current loop and the second current loop.

[0061] The thirteenth example embodiment includes the features of any one of the first to twelfth example embodiments, including the features of any one of the first to third example embodiments, wherein the first current loop includes a power switch, an active damper, and a resonant capacitor.

[0062] A fourteenth example embodiment includes the features of any one of the first to thirteenth example embodiments, wherein the second current loop includes a power switch, an active damper, and a DC link capacitor.

[0063] The fifteenth example embodiment includes the features of any one of the first to fourteenth example embodiments, wherein the power switch has a first voltage rating, the damper switch has a second voltage rating, and the first voltage rating is at least 5 times the second voltage rating.

[0064] The sixteenth example embodiment includes the features of any one of the first to fifteenth example embodiments, and includes a non-isolated power supply that is operably coupled to the power switch and the active damper, and the non-isolated power supply is configured to provide a drive voltage for the power switch and the active damper.

[0065] The seventeenth example embodiment includes the features of the sixteenth example embodiment, wherein the non-isolated power supply includes a resistor operably coupled to the voltage source at a first node and operably coupled to a capacitor and a Zener diode at a second node, the capacitor and the Zener diode being operably coupled in a parallel relationship.

[0066] An eighteenth example embodiment is a system comprising: a DC link including a first DC link rail node and a second DC link rail node; a first power switch coupled to the first DC link rail node and an output node, the first power switch being operable to connect and disconnect the first DC link rail node from the output node; a second power switch coupled to the output node and the second DC link rail node, the second power switch being operable to connect and disconnect the output node from the second DC link rail node; and a commutation loop coupled to one of the first and second DC link rail nodes and the output node, the commutation loop comprising a resonant capacitor and an active damper controllable to change a resistance of the commutation loop to a first resistance and a second resistance greater than the first resistance.

[0067] A nineteenth example embodiment includes the features of the eighteenth example embodiment, wherein the active damper comprises a bidirectional switch, the active damper providing a first resistance when the bidirectional switch is closed, and the active damper providing a second resistance when the bidirectional switch is open.

[0068] A twentieth example embodiment includes the features of the nineteenth example embodiment, wherein the first power switch has a first voltage rating, the bidirectional switch has a second voltage rating, and the second voltage rating is 20% or less of the first voltage rating.

[0069] A twenty-first example embodiment includes the features of any one of the eighteenth to twentieth example embodiments, and includes a second commutation loop operably coupled to the other of the first and second DC link rail nodes and the output node, and the second commutation loop includes a second resonant capacitor and an active damper.

[0070] The twenty-second example embodiment includes the features of the twenty-first example embodiment, wherein the active damper is controllable to suppress current and voltage ringing in the commutation loop, in the first main power path including the first power switch, in the second commutation loop, and in the second main power path including the first power switch.

[0071] A twenty-third example embodiment is a method of controlling operation of a power converter, the method comprising: performing a soft switching operation, the soft switching operation comprising closing a first power switch to connect a first DC link rail node with an output node, and opening a second power switch to disconnect a second DC link rail node from the output node; controlling an active damper to provide an undamped resistance during the soft switching operation, the active damper being in a commutation loop, the commutation loop comprising a resonant capacitor coupled to the output node; and controlling the active damper to provide a damping resistance after the soft switching operation is completed, the damping resistance being higher than the undamped resistance, the damping resistance attenuating current and voltage ringing in the commutation loop and in a second loop comprising the first power switch.

[0072] A twenty-fourth example embodiment includes the features of the twenty-third example embodiment, wherein the act of controlling the active damper to provide an undamped resistance occurs before initiation of the soft switching operation.

[0073] A twenty-fifth example embodiment includes the features of the twenty-third example embodiment, wherein the act of controlling the active damper to provide an undamped resistance occurs simultaneously with initiation of the soft switching operation.

[0074] A twenty-sixth example embodiment includes the features of the twenty-third example embodiment, wherein the act of controlling the active damper to provide the damping resistance occurs simultaneously with the end of the soft switching operation.

[0075] Although example embodiments of the present disclosure have been described and illustrated in detail in the drawings and the foregoing description, the example embodiments of the present disclosure are to be considered illustrative rather than restrictive in nature, and it should be understood that only certain example embodiments have been shown and described, and that protection is intended for all changes and modifications that come within the spirit of the claimed invention. It should be understood that although the use of words such as "preferred," "preferably," or "more preferred" in the above description indicates that the feature described may be more desirable, nonetheless, the feature may not be required, and embodiments lacking the feature may be considered to be within the scope of the present invention, which is defined by the appended claims. When reading the claims, it is intended that when words such as "a," "an," "at least one," or "at least one portion" are used, there is no intention to limit the claim to only one item, unless specifically stated to the contrary in the claim. When the language "at least a portion" and / or "a portion" is used, the item may include a portion and / or the entire item, unless specifically stated to the contrary.

Claims

1. A power converter comprising: a first power switch coupled between a first DC link rail node and an output node, and the first power switch operable to connect and disconnect the first DC link rail node from the output node; a first resonant capacitor coupled to the first power switch; an active damper coupled in series with the first resonant capacitor and the output node, the active damper comprising a damper switch controllable to provide a first resistance of the active damper in a first state and a second resistance of the active damper in a second state, the first resistance having a lower magnitude than the second resistance; a damper driver operatively coupled to the damper switch, the damper driver being configured to control the damper switch so that the damper switch is in the first state during a soft switching operation of the first power switch and is in the second state after the soft switching operation of the first power switch is completed; an auxiliary arm coupled between a DC link midpoint node and the output node, the auxiliary arm comprising an auxiliary switch connected in series with an inductor, the auxiliary switch operable to connect and disconnect the DC link midpoint node from the output node in coordination with operation of the first power switch to provide soft switching of the first power switch; a second power switch coupled between a second DC link rail node and the output node, the second power switch being operable to connect and disconnect the second DC link rail node from the output node; as well as a second resonant capacitor coupled between the second DC link rail node and a midpoint between the first resonant capacitor and the second resonant capacitor, The active damper is configured to suppress current and voltage ringing in a first commutation loop, in a first main power path including the first power switch, in a second commutation loop, and in a second main power path including the second power switch, the first commutation loop including a first resonant capacitor and the active damper. 2 . The power converter of claim 1 , wherein the damper driver is configured to control the damper switch such that the damper switch is in the first state before the soft switching operation of the first power switch is initiated. 3 . The power converter of claim 1 , wherein the damper driver is configured to control the damper switch so that the damper switch is switched to the first state simultaneously with the start of the soft switching operation of the first power switch. 4 . The power converter of claim 1 , wherein the damper driver is configured to control the damper switch so that the damper switch switches to the second state simultaneously with the end of the soft switching operation of the first power switch. The power converter of claim 1 , wherein the first resonant capacitor is coupled in parallel with the first power switch. The power converter of claim 1 , wherein the damper switch comprises a bidirectional switching device. 7 . The power converter according to claim 6 , wherein the bidirectional switch device comprises a first silicon metal oxide semiconductor field effect transistor (SiMOSFET) and a second SiMOSFET coupled in series with the first SiMOSFET in opposite polarity. 8 . The power converter of claim 1 , wherein the damper driver is configured to control the damper switch in response to a gate control signal for the first power switch. 9 . The power converter of claim 1 , wherein the damper driver is configured to control the damper switch in response to the sensed current and voltage values.

10. The power converter of claim 1, wherein a first loop comprises the second power switch, the active damper, and the second resonant capacitor. 11 . The power converter of claim 1 , wherein a second loop comprises the second power switch, the active damper, and a DC link capacitor. 12 . The power converter of claim 1 , wherein the first power switch has a first voltage rating, the damper switch has a second voltage rating, and the first voltage rating is at least 5 times greater than the second voltage rating.

13. The power converter of claim 1, comprising a non-isolated power supply operatively coupled to the first power switch and the active damper, and configured to provide a driving voltage for the first power switch and the active damper.

14. The power converter of claim 13 , wherein the non-isolated power supply comprises a resistor operably coupled to a voltage source at a first node and operably coupled to a capacitor and a Zener diode at a second node, the capacitor and Zener diode being operably coupled in parallel.

15. A system comprising a power converter, wherein the power converter is a power converter according to claim 1, the DC link comprising the first DC link rail node and a second DC link rail node; The system further comprises: a first commutation loop coupled to one of the first and second DC link rail nodes and the output node, the first commutation loop comprising the first resonant capacitor and an active damper coupled in parallel with the first power switch, the active damper configured to change a resistance of the first commutation loop to a first resistance and a second resistance greater than the first resistance; a second commutation loop coupled to the other of the first and second DC link rail nodes and the output node, and comprising the second resonant capacitor and an active damper coupled in parallel with the second power switch; and The active damper is configured to suppress current and voltage ringing in a first commutation loop, in a first main power path including the first power switch, in the second commutation loop, and in a second main power path including the second power switch.

16. The system of claim 15, wherein the active damper comprises a bidirectional switch, the active damper providing the first resistance when the bidirectional switch is closed, and the active damper providing the second resistance when the bidirectional switch is open. 17 . The system of claim 16 , wherein the first power switch has a first voltage rating, the bidirectional switch has a second voltage rating, and the second voltage rating is 20% or less of the first voltage rating.

18. A method of controlling operation of a power converter, the method comprising: providing a first commutation loop coupled to one of a first DC link rail node and a second DC link rail node and an output node, the first commutation loop comprising a first resonant capacitor, a first power switch coupled in parallel with the first resonant capacitor, and an active damper configured to change a resistance of the first commutation loop into a damping resistance and an undamped resistance greater than the damping resistance; providing an auxiliary arm coupled in series with a DC link midpoint node and the output node, the auxiliary arm including an auxiliary switch connected in series with an inductor, the auxiliary switch operable to connect and disconnect the DC link midpoint node from the output node in coordination with operation of the first power switch to provide soft switching of the first power switch; providing a second commutation loop coupled to the other of the first and second DC link rail nodes and the output node, the second commutation loop including a second resonant capacitor and an active damper, the second commutation loop including a second power switch connected in parallel with the second resonant capacitor; performing a soft switching operation, the soft switching operation comprising closing the first power switch to connect the first DC link rail node with the output node, and opening the second power switch to disconnect the second DC link rail node from the output node; controlling the active damper to provide the undamped resistance during the soft switching operation; as well as controlling the active damper to provide the damping resistance after the soft switching operation is completed, the damping resistance attenuating current and voltage ringing in the first commutation loop and in the second commutation loop, and The active damper is configured to suppress current and voltage ringing in a first main power path including the first power switch and in a second main power path including the second power switch.

19. The method of claim 18, wherein controlling the active damper to provide the undamped resistance occurs before initiation of the soft switching operation.

20. The method of claim 18, wherein the act of controlling the active damper to provide the undamped resistance occurs simultaneously with initiation of the soft switching operation.

21. The method of claim 18, wherein the act of controlling the active damper to provide the damping resistance occurs simultaneously with the end of the soft switching operation.

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