Apparatus and method with power conversion using multiple rectifier circuits

Abstract

To provide an apparatus with power conversion using a plurality of rectifier circuits.SOLUTION: An apparatus includes a direct current (DC) to alternating current (AC) inversion circuit, a first circuit, a second circuit, and an output circuit. The DC-AC inverter circuit inverts at least one DC input signal corresponding to the input voltage into at least one AC signal. The first circuit and the second circuit each comprise an inductively isolated circuit responsive to power from the at least one alternating current signal to drive the inductively isolated circuit, and a rectifier circuit responsive to the inductively isolated circuit by outputting a first rectified signal and a second rectified signal, wherein at least one of the first rectifier circuit and the second rectifier circuit is limited by a voltage breakdown rating. The output circuit provides a DC output voltage signal, cascades a plurality of signals including the first rectified signal and the second rectified signal, is dependent on the first rectified signal and the second rectified signal, and is greater than a voltage breakdown rating.SELECTED DRAWING: Figure 1

Description

[Background technology]

[0001] High voltage (e.g., 10-100 kilovolts), low current (1-100 milliamps) power sources can be beneficial in numerous applications, including medical, environmental, security, and aerospace applications, among others. Additionally, increased portability of high voltage devices can lead to new uses, improved performance, and / or new applications of the technology.

[0002] These and other issues have presented challenges to power conversion in a variety of applications. Summary of the Invention

[0003] Aspects of various embodiments are directed to apparatus and / or methods comprising power conversion using multiple rectifier circuits. In the following description, various implementations and applications are disclosed to provide an understanding of the present disclosure through non-limiting exemplary embodiments.

[0004] Various aspects are directed to and / or include power conversion provided by multiple stacked rectifier circuits, at least one of which has inductive isolation between a front-end portion and a back-end portion, the back-end portion operable to provide a power converted output stage signal having a steady-state voltage significantly greater than a voltage stress / breakdown rating associated with one or more elements of the front portion.

[0005] Many aspects are directed to a power converter having a class DE resonant rectifier with capacitive direct current (DC) isolation for generating hundreds of volts. With the rectifier diodes and output terminals DC-isolated from the input, dozens of rectifier units are stacked, resulting in the signals output by the units being serially connected, generating an output voltage of several kilovolts. In this configuration, with the isolated total output voltage symmetrically branched in the positive and negative directions, the output voltage can be up to twice the voltage rating of the DC-isolation capacitors because the voltage stress on the capacitors of the top and bottom rectifiers is half the total output voltage. To achieve higher output voltages, various embodiments include an air-core transformer that acts as an additional DC isolation barrier. As described above, multiple units of the multi-stage class DE rectifier can be cascaded. Using such an exemplary configuration, high output voltages can be generated because the achievable voltage is the breakdown voltage of the inductive isolation barrier between the primary and secondary windings of the transformer.

[0006] A more specific aspect is directed to an apparatus including a DC-to-AC (AC) inverter circuit, a first circuit, a second circuit, and an output circuit. The DC-to-AC inverter circuit inverts at least one DC input signal corresponding to an input voltage into at least one AC signal. The first circuit includes a first inductive isolation circuit responsive to power from the at least one AC signal and a first rectifier circuit. The first rectifier circuit responds to the first inductive isolation circuit by outputting a first rectified signal to a first pair of output terminals. The second circuit includes a second inductive isolation circuit responsive to power from the at least one AC signal and a second rectifier circuit. The second rectifier circuit responds to the second inductive isolation circuit by outputting a second rectified signal to a second pair of output terminals. At least one of the first rectifier circuit and the second rectifier circuit is limited by a voltage breakdown rating. The output circuit provides a DC output voltage signal between the voltage source terminals and cascades a plurality of signals including the first rectified signal and the second rectified signal, with one of the output terminals of one of the pair of output terminals being a source of supply to one of the other output terminals of the pair of output terminals. The voltage source terminals provide a voltage source slaved to the first rectified signal and the second rectified signal and greater than a voltage breakdown rating of at least one of the first rectifier circuit and the second rectifier circuit.

[0007] In related more specific aspects, each of the first and second rectifier circuits includes or is configured as a class DE rectifier, and / or each rectifier circuit is one of a multi-stage rectifier connected in parallel. A voltage breakdown rating is defined by a DC isolation capacitor used in the signal path of one of the first and second circuits between the output terminal of the inductive isolation circuit and the diode of the rectifier circuit. In certain embodiments, at least one of the first and second rectifier circuits provides a DC output voltage signal for an associated rectified signal that is greater than two times the voltage breakdown rating of at least one of the first and second rectifier circuits. In more specific related embodiments, the DC output voltage signal is greater than three, four, five, six, or more times the voltage breakdown rating.

[0008] At least one of the first inductive isolation circuit and the second inductive isolation circuit is associated with another voltage breakdown rating that is greater than the voltage breakdown rating of at least one of the first rectifier circuit and the second rectifier circuit, for example, the first inductive isolation circuit and the second inductive isolation circuit each include an air core transformer having an associated voltage breakdown rating that is greater than the voltage breakdown rating of at least one of the first rectifier circuit and the second rectifier circuit, defining a minimum overall voltage breakdown rating for circuits included in the inductive isolation circuit.

[0009] In many related aspects, the apparatus further includes additional rectifier circuits having outputs cascaded with the first rectifier circuit and the second rectifier circuit, each of which includes or is configured as a class DE rectifier, is DC isolated from the input voltage, and / or is rated for 300 volts or greater. The apparatus further includes a third circuit having a third inductively isolated circuit responsive to power from the at least one AC signal, and the third rectifier circuit responsive to the third inductively isolated circuit by outputting a third rectified signal to a third pair of output terminals. The output circuit provides a DC output voltage signal between the voltage source terminals and cascades multiple signals including the first rectified signal, the second rectified signal, and the third rectified signal by coupling selected ones of the output terminals of the first pair, the second pair, and the third pair of output terminals as a cascaded source of power to the first voltage source terminal, the second voltage source terminal, and the third voltage source terminal collectively arranged to provide a voltage source slaved to the first rectified signal, the second rectified signal, and the third rectified signal and greater than the voltage breakdown rating. In such a configuration, the input terminals to the multiple rectifier circuits are in parallel and the output terminals are in series.

[0010] Another aspect is directed to a DC power supply for providing a DC voltage in response to at least one AC signal related to an input voltage signal. The DC power supply includes a first circuit, a second circuit, and an output circuit. The first circuit includes a first inductive isolation circuit responsive to power from the at least one AC signal and a first rectifier circuit responsive to the first inductive isolation circuit by outputting a first rectified signal on a first pair of output terminals. The second circuit includes a second inductive isolation circuit responsive to power from the at least one AC signal and a second rectifier circuit responsive to the second inductive isolation circuit by outputting a second rectified signal on a second pair of output terminals, at least one of the first rectifier circuit and the second rectifier circuit being limited by a voltage breakdown rating. The output circuit provides a DC output voltage signal between the voltage source terminals and cascades a plurality of signals including the first rectified signal and the second rectified signal with one of the output terminals of the pair of output terminals being a source to one of the other output terminals of the pair of output terminals, the voltage source terminals providing a voltage source slaved to the first rectified signal and the second rectified signal and greater than a voltage breakdown rating of at least one of the first rectifier circuit and the second rectifier circuit.

[0011] As described above, each of the first inductive isolation circuit and the second inductive isolation circuit comprises an air-core transformer having a voltage breakdown rating greater than that of at least one of the first rectifier circuit and the second rectifier circuit, the voltage breakdown rating being associated with a material between the windings of the air-core transformer. At least one of the first rectifier circuit and the second rectifier circuit comprises a DC isolation capacitor used in a signal path of one of the first circuit and the second circuit between the output terminal of the inductive isolation circuit and the diode of the rectifier circuit. The DC isolation capacitor is characterized by being limited by the voltage breakdown rating. The device further comprises a plurality of circuits, including a first circuit and a second circuit, cascaded in an arrangement between voltage rails, with at least one of the first rectifier circuit and the second rectifier circuit each disposed proximate to one of the voltage rails.

[0012] In many related, more specific aspects, the DC power source and / or the device including the DC power source further includes a front-end drive circuit that provides at least one AC signal to the first inductive isolation circuit and the second inductive isolation circuit. In more specific aspects, the front-end drive circuit includes one or more DC-to-AC inverter circuits configured and arranged to invert at least one DC input signal corresponding to the input voltage signal into at least one AC signal and drive the first inductive isolation circuit and the second inductive isolation circuit via the at least one AC signal. In another aspect, the front-end drive circuit includes an AC-to-AC inverter circuit configured and arranged to invert the input voltage signal and the at least one AC input signal corresponding to a first frequency into at least one AC signal corresponding to a second frequency and drive the first inductive isolation circuit and the second inductive isolation circuit via the at least one AC signal at the second frequency.

[0013] Numerous aspects are directed to methods of power conversion using one or more of the above-described devices. The method includes providing at least one alternating current (AC) signal from a direct current (DC) voltage input signal and using parallel first and second circuits, each providing inductive isolation, driving in response to power from the at least one AC signal, and rectifying in response to the inductive isolation by outputting a rectified signal at an associated pair of output terminals. The rectification associated with at least one of the first and second circuits is characterized by being limited by a voltage breakdown rating. The method further includes providing a DC output voltage signal between the voltage source terminals by cascading a plurality of signals, including the rectified signal, to a DC output voltage signal dependent on the rectified signal and greater than the voltage breakdown rating.

[0014] Accordingly, various embodiments are directed to solving the above-mentioned problems and others that may be beneficial to various power converters and / or multi-stage rectifiers. The above description / summary is not intended to describe each embodiment or every implementation of the present disclosure. The following figures and detailed description also illustrate various embodiments.

[0015] Various exemplary embodiments may be more fully understood in consideration of the following detailed description in conjunction with the accompanying drawings. [Brief explanation of the drawings]

[0016] [Figure 1] FIG. 1 illustrates an example of an apparatus with power conversion according to various embodiments of the present disclosure. [Figure 2] 2A-2B illustrate another example of an apparatus with power conversion according to various embodiments of the present disclosure. [Figure 3] FIG. 3 illustrates an example of a front-end driver circuit for an apparatus according to various embodiments of the present disclosure. [Figure 4] 4A-4C show experimental examples of inductive isolation circuits of devices according to various embodiments of the present disclosure. [Figure 5] 5A-5B show experimental examples of multi-stage rectifiers of devices according to various embodiments of the present disclosure. [Figure 6] 6A-6C show example experimental results for power converters according to various embodiments of the present disclosure. [Figure 7] 7A-7D show example experimental results for another power converter, according to various embodiments of the present disclosure. [Figure 8] 8A-8B show example experimental performance results of another power converter according to various embodiments of the present disclosure. [Figure 9] FIG. 9 illustrates an example of a computed tomography (CT) scanner having an apparatus according to various embodiments of the present disclosure. [Figure 10] FIG. 10 illustrates an example of a traveling wave tube (TWT) radar power supply, according to various embodiments of the present disclosure.

[0017] The various embodiments described herein are susceptible to modification and alteration, aspects of which have been shown by way of example in the drawings and will be described in detail. It is understood, however, that the intention is not to limit the disclosure to the particular embodiments. Rather, the intention is to cover all modifications, equivalents, or alternatives within the scope of the disclosure, including aspects defined in the claims. Also, the term "example" as used throughout this application is for purposes of illustration only and is not limiting. DETAILED DESCRIPTION OF THE INVENTION

[0018] Aspects of the present disclosure are believed to be applicable to various types of devices, systems, and methods involving power conversion using multiple rectifier circuits. In certain embodiments, the power converter outputs a voltage greater than twice the breakdown voltage rating of the capacitors of the multiple rectifier circuits cascaded in layers. While the present invention is not necessarily limited to such applications, various aspects of the present invention are utilized to illustrate various examples using this context.

[0019] Thus, in the following description, various details are used to describe specific examples of the present specification. However, it will be apparent to one skilled in the art that one or more alternative examples and / or variations of these examples may be practiced without all of the specific details described below. For example, well-known features will not be described in detail so as not to obscure the description of the examples of the present specification. For simplicity of description, the same reference numbers may be used in different figures to refer to the same element or additional instances of the same element. Also, although aspects and features in some cases are described in separate figures, it will be understood that features from one figure or embodiment can be combined with features from another figure or embodiment, even if the combination is not explicitly stated or is not explicitly stated as a combination.

[0020] Certain example embodiments are directed to a power converter having multiple inductively isolated stacked rectifier circuits. For example, at least one rectifier circuit has inductive isolation between a front-end section and a back-end section, allowing the back-end section to be used to provide a power-converted output-stage signal with a steady-state voltage significantly greater than a voltage breakdown rating associated with one or more elements of the back-end section. One or more elements may include one or more DC-isolation capacitors in the rectifier circuit that provide DC isolation for the rectifier diodes. Further inductive isolation is provided by an inductive isolation circuit, such as an air-core transformer, between the front-end section and the back-end section. The front-end section is referred to herein as a "front-end drive circuit." The back-end section includes multiple rectifier circuits. The inductive isolation circuit can increase the maximum output voltage of the power converter circuit compared to a voltage breakdown rating associated with one or more elements of the back-end section. For example, embodiments may include inductively isolating the front-end drive circuit from the rectifier circuit and using it to provide a power-converted output-stage signal with a steady-state voltage greater than twice the voltage breakdown rating associated with each rectifier circuit element. Such an embodiment may include the use of multiple rectifier circuits arranged in cascade between the voltage rails, with at least two rectifier circuits each arranged closest to a voltage rail.

[0021] Certain embodiments are directed to solving challenges related to high DC voltages. High DC voltages, such as tens of kilovolts (kV) or higher, are beneficial for various systems, devices, and / or methods. Small, lightweight, high-wattage power supplies are often used to improve the portability of the devices described below without compromising their performance. As described further herein, various embodiments are directed to small, lightweight, high-voltage power (i.e., DC-DC) converters with fast transient response that may be used for various applications. Some exemplary systems, devices, and / or methods include electrostatic precipitators (ESPs), X-ray and neutron sources for airport security, weapons and explosives detection, and medical equipment such as dental X-ray or computed tomography (CT) scanners.

[0022] Certain aspects of the present disclosure are directed to power conversion provided by multiple stacked rectifier circuits, such as multi-stage class DE rectifiers, with inductive isolation that exceeds the limits set by the capacitor voltage ratings of the class DE rectifiers. Inserting an air-core transformer improves the DC voltage isolation capability against the breakdown voltage of the material between the transformer windings. Furthermore, parallel connection of the stages allows for fast rise times, making the circuit particularly suitable for systems requiring pulsed DC voltages. Various embodiments include multiple stacked rectifier circuits, such as multi-stage class DE rectifiers, that allow all input terminals of the rectifiers to be connected in parallel and all output terminals in series, thereby providing current from the input to all nodes simultaneously. In such a configuration, the maximum number of cascaded rectifier stages is limited by the voltage ratings of the top and bottom DC isolation capacitors, and therefore the converter output voltage does not exceed twice the capacitor voltage rating. Further specific embodiments of the present disclosure include multiple stacked rectifier circuits with inductive isolation that exceeds the limits set by the capacitor voltage ratings. The insertion of an air-core transformer improves the DC voltage insulation capability against the breakdown voltage of the material between the transformer windings. Furthermore, the parallel connection of the stages allows for fast rise times, making the circuit particularly suitable for systems requiring pulsed DC voltages.

[0023] Certain exemplary embodiments are directed to a method and / or apparatus comprising a DC-to-AC inverter circuit, a first circuit, a second circuit, and an output circuit. The DC-to-AC inverter circuit inverts at least one DC input signal corresponding to an input voltage into at least one AC signal. The first circuit comprises a first inductive isolation circuit responsive to power from the at least one AC signal and a first rectifier circuit. The first rectifier circuit responds to the first inductive isolation circuit by outputting a first rectified signal to a first pair of output terminals. The second circuit comprises a second inductive isolation circuit responsive to power from the at least one AC signal and a second rectifier circuit. The second rectifier circuit responds to the second inductive isolation circuit by outputting a second rectified signal to a second pair of output terminals. At least one of the first rectifier circuit and the second rectifier circuit is characterized by a voltage breakdown rating. The output circuit provides a DC output voltage signal between the voltage source terminals and cascades a plurality of signals including the first rectified signal and the second rectified signal, with one of the output terminals of one of the pair of output terminals being a source of supply to one of the other output terminals of the pair of output terminals. The voltage source terminals provide a voltage source slaved to the first rectified signal and the second rectified signal and greater than a voltage breakdown rating of at least one of the first rectifier circuit and the second rectifier circuit.

[0024] In a related more specific aspect, each rectifier circuit includes or is configured as a class DE rectifier, and / or each rectifier circuit is one of multiple rectification stages connected in parallel. A voltage breakdown rating is defined by a DC isolation capacitor used in the signal path of one of the first and second circuits between the output terminals of the inductive isolation circuit and the diodes of the rectifier circuits. In certain embodiments, at least one of the rectifier circuits provides a DC output voltage signal for an associated rectified signal that is greater than twice the voltage breakdown rating of at least one of the first and second rectifier circuits.

[0025] At least one of the inductive isolation circuits may be associated with another voltage breakdown rating that is greater than the voltage breakdown rating of at least one of the first rectifier circuit and the second rectifier circuit, for example, the first inductive isolation circuit and the second inductive isolation circuit each include an air core transformer having an associated voltage breakdown rating that is greater than the voltage breakdown rating of at least one of the first rectifier circuit and the second rectifier circuit, defining a minimum overall voltage breakdown rating for circuits included in the inductive isolation circuit.

[0026] The above apparatus may further include additional rectifier circuits having outputs cascaded with the first rectifier circuit and the second rectifier circuit, each of which may include or be configured as a class DE rectifier, be galvanically isolated from the input voltage, and / or be rated for 300 volts or greater. For example, the apparatus may further include a third circuit having a third inductively isolated circuit responsive to power from the at least one AC signal, and a third rectifier circuit responsive to the third inductively isolated circuit by outputting a third rectified signal to a third pair of output terminals. The output circuit provides a DC output voltage signal between the voltage source terminals and cascades a plurality of signals including the first rectified signal, the second rectified signal, and the third rectified signal by coupling selected ones of the output terminals of the first pair, the second pair, and the third pair of output terminals as a cascaded source of power to the first voltage source terminal, the second voltage source terminal, and the third voltage source terminal collectively arranged to provide a voltage source slaved to the first rectified signal, the second rectified signal, and the third rectified signal and greater than the voltage breakdown rating.

[0027] Another embodiment is directed to a DC power supply for supplying a DC voltage in response to at least one AC signal related to an input voltage signal. The DC power supply comprises the first circuit described above, a second circuit, and an output circuit. As described above, each of the first inductive isolation circuit and the second inductive isolation circuit comprises an air-core transformer having a voltage breakdown rating greater than the voltage breakdown rating of at least one of the first rectifier circuit and the second rectifier circuit, the voltage breakdown rating being associated with material between the windings of the air-core transformer. At least one of the first rectifier circuit and the second rectifier circuit comprises a DC isolation capacitor used in a signal path of one of the first circuit and the second circuit, the DC isolation capacitor being limited by the voltage breakdown rating. The apparatus further comprises a plurality of circuits, including the first circuit and the second circuit, cascaded in an arrangement between voltage rails, with at least one of the first rectifier circuit and the second rectifier circuit each disposed proximate one of the voltage rails.

[0028] In many related, more specific aspects, the apparatus further comprises a front-end drive circuit that provides at least one AC signal to the first inductive isolation circuit and the second inductive isolation circuit. The front-end drive circuit comprises one or more DC-to-AC inverter circuits that invert at least one DC input signal corresponding to an input voltage into at least one AC signal and drive the first inductive isolation circuit and the second inductive isolation circuit via the at least one AC signal. In another embodiment, the front-end drive circuit comprises one or more AC-to-AC inverter circuits that invert at least one AC input signal corresponding to a first frequency (and input voltage) into at least one AC signal corresponding to a second frequency and drive the first inductive isolation circuit and the second inductive isolation circuit via the at least one AC signal at the second frequency.

[0029] One or more embodiments are directed to systems and / or methods including computed tomography (CT) scanner gantries and other devices (e.g., centrifugal-type devices) having high-speed rotating members, such as rotating gantry members. CT scanners are designed and / or configured based on power conversion circuitry and their weight to allow for faster rotational speeds, with the upper speed limit at least partially due to the power conversion circuitry that provides power to the CT scanner. For example, the overall use and weight of a CT scanner is related to the particular rotational speed at which the gantry rotates. Because faster rotation exposes the patient to radiation for a shorter period of time (e.g., for localized irradiation), faster rotational speeds, combined with shorter output voltage ramp-ups and ramp-downs, reduce patient exposure.

[0030] One or more other embodiments are directed to a machine including a traveling wave tube (TWT) radar power supply having the power conversion circuit described above. The power conversion circuit reduces the overall system size, allowing powerful radar systems that were previously too large due to their system size and weight to be used in mobile applications or mounted in smaller vehicles (e.g., drones, cars, etc.). For example, the weight of a machine depends on the weight associated with the power conversion circuit used to power the circuitry used to prepare electrostatic bonding.

[0031] Those skilled in the art will understand that embodiments are not limited to the above systems and / or methods. Other systems and / or methods that include the above power conversion include electrostatic painting, electrohydrodynamic propulsion devices, high-power laser power supplies, TASER guns, particle accelerators, plasma generators, capacitor charging, and ozone generators, among other types of systems and / or methods. Some embodiments include or comprise a medical system (e.g., an X-ray machine) that includes a gantry capable of providing a voltage-based radiation dose to a patient, the medical system being designed and / or configured to include a gantry configured to rotate at a high speed, the upper limit of which is limited at least in part by the power conversion circuitry, and the radiation dose being determined at least in part by the upper limit rotational speed of the gantry. Another embodiment includes or comprises an ion source machine (e.g., an x-ray machine, a linear accelerator, a neutron generator for explosive detection, a drill head / system configured for drilling / imaging for oil logging and geological exploration) with a voltage-based member or voltage-based gantry, where the ion source machine is constructed and arranged to be portable as a handheld machine, the weight of the handheld machine being dependent on the weight associated with the power conversion circuitry used to affect rotation of the voltage-based member or voltage-based gantry. An additional embodiment includes or comprises a machine configured to provide electrostatic bonding, the weight of the machine being dependent on the weight associated with the power conversion circuitry used to power the circuitry used to prepare for electrostatic bonding.

[0032] The above-described devices can be used to implement various methods for converting electrical power, as further described herein.

[0033] Referring to the drawings, Figure 1 illustrates an example of an apparatus comprising power conversion, according to various embodiments of the present disclosure. As shown, the apparatus comprises a front-end drive circuit 102, first and second circuits (described in detail below), and an output circuit 112. In various embodiments, the apparatus comprises a power converter comprising a cascaded inverter circuit, an inductive isolation circuit, and a rectifier circuit. As described further herein, the first and second circuits comprise inductive isolation circuits 104 and 108 and rectifier circuits 106 and 110, respectively.

[0034] The front-end drive circuit 102 provides an oscillating signal, such as one or more AC signals, to the inductive isolation circuits 104 and 108. In certain embodiments, the front-end drive circuit 102 also provides at least one DC input signal (e.g., V DD The front-end drive circuit 102 includes one or more DC-to-AC inverter circuits 103 and 105 that convert the AC input signal at a first frequency into at least one AC signal. While the first and second circuits are described one by one below, the embodiments are not limited to these. The at least one AC signal is used to drive the first and second circuits. Furthermore, the embodiments are not limited to DC-to-AC inverter circuits. For example, the front-end drive circuit 102 may include a circuit that provides an oscillation signal. In some specific embodiments, the front-end drive circuit 102 includes one or more AC-to-AC inverter circuits that convert an AC input signal at a first frequency into an output AC signal at a second frequency. In alternative and / or additional embodiments, the front-end drive circuit 102 directly induces the AC signal.

[0035] The first and second circuits each include an inductive isolation circuit 104 and 108 and a rectifier circuit 106 and 110. For example, the first circuit includes a first inductive isolation circuit 104 that operates in response to power from at least one AC signal, and a first rectifier circuit 106. The first rectifier circuit 106 responds to the first inductive isolation circuit 104 by outputting a first rectified signal to a first pair of output terminals. The second circuit includes a second inductive isolation circuit 108 that operates in response to power from the at least one AC signal, and a second rectifier circuit 110 that responds to the second inductive isolation circuit 108 by outputting a second rectified signal to a second pair of output terminals. As described further herein, the first rectifier circuit 106 and / or the second rectifier circuit 110 may include one or more DC isolation capacitors used in the signal path of one of the first and second circuits between the output terminals of the inductive isolation circuits 104 and / or 108 and the diodes of the rectifier circuits 106 and / or 110. For example, the first rectifier circuit 106 and / or the second rectifier circuit 110 may be configured as a Class DE rectifier. In such embodiments, the first and second circuits are characterized by being limited by a voltage breakdown rating that may be associated with the DC isolation capacitor. As described further herein, it will be apparent that the capacitor may have a voltage breakdown rating that defines the breakdown of the capacitor.

[0036] The first inductive isolation circuit 104 and the second inductive isolation circuit 108 comprise a transformer, such as an air core transformer. One or more of the first inductive isolation circuit 104 and the second inductive isolation circuit 108 are associated with another voltage breakdown rating that is greater than the voltage breakdown rating of at least one of the first rectifier circuit 106 and the second rectifier circuit 110 and / or defines a minimum overall voltage breakdown rating for the circuits included in the first inductive isolation circuit 104 and the second inductive isolation circuit 108.

[0037] The rectifier circuits may be in a cascade arrangement, with output circuit 112 influencing or providing the cascade connection between rectifier circuits 106 and 110. As used herein, output circuit 112 includes or refers to wiring used to influence the cascade connection of the rectifier circuits. For example, output circuit 112 provides a DC output voltage signal between voltage source terminals and cascades multiple signals including a first rectified signal and a second rectified signal, with one output terminal of one of the pair of output terminals being the source of a supply to one of the other output terminals of the pair of output terminals. The voltage source terminal provides a voltage source slaved to the first rectified signal and the second rectified signal and greater than the voltage breakdown rating of at least one of the first rectifier circuit and the second rectifier circuit. As further described herein, at least one of the rectifier circuits 106 and 110 provides a DC output voltage signal that is greater than twice the voltage breakdown rating of at least one of the first rectifier circuit 106 and the second rectifier circuit 110 for the associated rectified signal.

[0038] In certain embodiments, each of rectifier circuits 106 and 110 is one of multiple rectification stages connected via output circuit 112. For example, the input terminals are in parallel and the output terminals are in series. While the embodiment of FIG. 1 shows two stages (e.g., two rectifiers), embodiments are not so limited. For example, the device may include additional rectifier circuits having outputs cascaded to first rectifier circuit 106 and second rectifier circuit 110. Each of the rectifier circuits may include or be configured as a class DE rectifier, be galvanically isolated from the input voltage, and / or be rated for 300 volts or greater. In a more specific example, the device may further include at least one additional circuit, including a third circuit having a third inductively isolated circuit responsive to power from at least one AC signal, and the third rectifier circuit responsive to the third inductively isolated circuit by outputting a third rectified signal to a third pair of output terminals. The output circuit 112 provides a DC output voltage signal between the voltage source terminals and cascades multiple signals including the first rectified signal, the second rectified signal, and the third rectified signal by coupling selected ones of the output terminals of the first pair, the second pair, and the third pair of output terminals as a cascaded source of power to the first voltage source terminal, the second voltage source terminal, and the third voltage source terminal that are slaved to the first rectified signal, the second rectified signal, and the third rectified signal and are collectively arranged to provide a voltage source greater than the voltage breakdown rating.

[0039] While the embodiment of Figure 1 illustrates an apparatus including a front-end drive circuit 102, embodiments are not so limited. For example, the apparatus may include a DC power supply that provides a DC voltage in response to at least one AC signal related to an input voltage signal. As described and illustrated by Figure 1, the DC power supply includes the first circuit (e.g., first inductive isolation circuit 104 and first rectifier circuit 106), a second circuit (e.g., second inductive isolation circuit 108 and second rectifier circuit 110), and an output circuit 112.

[0040] The above-described apparatus may include a power converter with one or more rectifier circuits with inductive isolation that overcomes the limitations imposed by capacitor voltage ratings. The use of an air-core transformer improves the DC voltage insulation capability against the breakdown voltage of the material between the transformer windings. Furthermore, the parallel connection of the rectifier stages allows for sufficient rise time, making the circuit suitable for systems requiring pulsed DC voltage.

[0041] 2A and 2B illustrate another example of an apparatus including power conversion, according to various embodiments of the present disclosure. Similar to FIG. 1, the apparatus shown in FIG. 2A includes an inverter circuit 220, an inductive isolation circuit 222, and a plurality of rectifier circuits 224-1, 224-2, ... 224-N (referred to herein as "rectifier circuits 224" for ease of explanation).

[0042] The rectifier circuits 224 may be arranged as a multi-stage class DE rectifier. Each rectifier circuit 224 is connected via an output circuit that connects the rectifier's input terminals (or ports) in parallel and its output terminals (or ports) in series, thereby simultaneously providing current from the input to each rectifier circuit 224. The rectifier circuits are thus in a cascade configuration. The device may include multiple circuits, including the first and second circuits shown in FIG. 1, cascaded in an inter-voltage rail configuration. At least the circuits closest to each voltage rail, and in some embodiments, all of the circuits, may comprise a class DE rectifier with at least one DC isolation capacitor coupled to an air-core transformer that provides additional isolation. In certain embodiments, the rectifier circuits 224 in the stack may have input terminals / ports connected in parallel (e.g., via the output circuit) and output terminals / ports connected in series.

[0043] An example of a class DE rectifier 224-2 with an output circuit is shown in FIG. 2B. As shown, the class DE rectifier 224-2 includes one or more DC isolation capacitors that isolate the rectifier diodes when the rectifier circuit 224 outputs a DC output voltage signal. More specifically, DC isolation capacitors are used in one or more signal paths of the first and second circuits between the output terminals of the inductive isolation circuit and the diodes of the rectifier circuit 224. Once the rectifier diodes and output terminals are DC isolated from the input, the output terminals of the rectifiers are in series, and multiple units of the rectifier are stacked to provide a specific voltage output. In some embodiments, 20 300V rectifiers are stacked and used to provide a 6kV voltage, although embodiments are not limited thereto. As noted above, the DC isolation capacitors are characterized by a voltage breakdown rating.

[0044] According to various embodiments, the number of cascaded rectification stages is not limited by the voltage breakdown rating of the DC isolation capacitors in one or more stages, such as the top and bottom stages, and therefore the output voltage of the power converter may exceed twice the voltage breakdown rating of each capacitor in one or more rectification circuits 224. In certain embodiments, including those described above, the output voltage Vout is limited by the voltage breakdown rating of the DC isolation capacitors C, as shown by FIG. Bt and C Bb , due to the additional DC isolation provided by the inductive isolation circuit 222. To achieve higher output voltages, various embodiments include an air core transformer that acts as an additional DC isolation barrier. Without the additional DC isolation, under the condition that the isolated total output voltage branches symmetrically in the positive and negative directions, the output voltage Vout may be up to twice the voltage rating of the DC isolation capacitors, since the voltage stress on the capacitors of the top and bottom rectifiers is half of the total output voltage. In general, if the number of cascaded class DE rectifiers is N and the DC isolation capacitance is significantly larger than the diode branch capacitance, the voltage stress on the N-stage capacitors is given by C Bt、n The voltage stress of

number

number

[0045] According to various embodiments described above, the apparatus may be used to implement various methods. An example method includes providing at least one AC signal from a DC voltage input signal and using first and second circuits, each providing inductive isolation, each driven in response to power from the at least one AC signal, and each performing rectification in response to the inductive isolation by outputting a rectified signal on an associated pair of output terminals. As described above, each rectification circuit is connected via an output circuit connecting the rectifier input terminals in parallel and the output terminals in series. The rectification associated with at least one of the first and second circuits is associated with a circuit characterized by being limited by a voltage breakdown rating. The method further includes cascading multiple signals, including the rectified signal (e.g., first and second), to a DC output voltage signal dependent on the rectified signal and greater than the voltage breakdown rating.

[0046] Additionally, the above-described devices can be used in a variety of applications, such as various systems, devices, and / or methods. Some exemplary systems, devices, and / or methods include electrostatic precipitators (ESPs), X-ray and neutron sources for airport security, weapons and explosives detection, and medical equipment such as dental X-ray or computed tomography (CT) scanners.

[0047] As a specific example, an ESP is an air cleaning device that uses high voltage to electrostatically collect and subsequently remove dust particles. ESPs represent a viable solution to the air pollution problem that kills 43 million people each year. ESP designs using power converters according to various embodiments can be installed in smaller spaces and / or require less high power, thereby enabling the minimization and use of ESPs in rural areas of developing countries.

[0048] CT scanners comprise another specific example. To obtain images of the human body, CT scanners use x-rays generated from high electric fields. CT scans expose patients to potentially harmful radiation. While exposure levels can be reduced by rapidly modulating the x-ray source, CT scanners using various embodiments of power converters can provide sufficiently fast rise and fall times (e.g., 10-100 us). Such exemplary CT scanners can shorten the CT scan time required for a patient in a clinical setting because the scanner rotates faster, reducing mechanical stress on the rotating parts. In such embodiments, the weight and size of the onboard electronics are reduced, allowing the system to rotate faster and reducing scan time.

[0049] Another specific example includes electrohydrodynamic (EHD) ion-propulsion aircraft, an emerging aerospace technology in which thrust is generated by multiple pairs of electrodes that ionize air molecules. EHD could be used for silent unmanned aerial vehicles, which could be useful in military operations. To achieve this, a power source light enough for flight would be used, while providing power to the aircraft at hundreds of watts and voltages approaching 100 kV.

[0050] Other systems, devices, and / or methods may include high-power electronics used in security scanners that use x-ray, ion, and neutron sources. Such scanners are used for cargo inspection at airports, borders, checkpoints, and the like. If made as portable devices, such scanners may be useful to explosive ordnance disposal units or law enforcement officers, such as border patrol. High-performance neutron generators may also be beneficial to the petroleum industry, as they are widely used in oil well logging operations.

[0051] Embodiments may include, but are not limited to, various applications and / or methods relating to compact, lightweight, fast-response high-voltage power (eg, DC-DC) converters.

[0052] As noted above, various embodiments are directed to devices comprising power conversion. In certain embodiments, the device includes multiple stacked rectifier circuits (e.g., multi-stage rectifiers, such as the series 300VDE resonant-class rectifiers shown in FIG. 2B). The device may include an air-core transformer that serves as an additional DC isolation barrier. As noted above and further illustrated in Appendix A of the basic provisional application, FIG. 2B illustrates an example of a 300VDE resonant-class rectifier with capacitive DC isolation that may be used in a high-voltage generator. Because the rectifier diodes and output terminals are DC isolated from the input, multiple units (e.g., 20 units) of the 300V rectifier may be stacked to generate a 6kV voltage output, as shown in FIG. 2B and FIG. lb of Appendix A. Using the example device shown in FIG. 2A, high output voltages can be generated because the limit of the achievable voltage is the breakdown voltage of the inductive isolation barrier between the primary and secondary windings of the transformer.

[0053] In various embodiments, a device that may include an inverter circuit described herein converts a DC input into a high-frequency AC voltage. The device may include a full-bridge resonant inverter implemented for the DC-to-AC stage. Various embodiments are directed to a device that includes an inverter circuit, a multi-layer rectifier circuit, and a transformer circuit. An example PCB transformer design is further illustrated in Figure 4A and in Figures 3a-3d of Appendix A.

[0054] Various experimental embodiments are directed to a multi-stage class DE rectification structure with inductive isolation. High frequency operation allows for fast transient response in the output voltage. An input-parallel output-series structure using an air-core PCB with high DC voltage isolation capability results in a high achievable output voltage for the DC-DC converter. A 60V to 6kV DC-DC converter is demonstrated at a 1.25MHz switching frequency capable of delivering 36W of power to the load, and a high-gain DC-DC converter in a multi-stage configuration capable of pulsing the output with a rise time of 296 microseconds (μs) and delivering 35kV and 203 watts (W) of power to the load while maintaining 73 percent efficiency.

[0055] 3 illustrates an example front-end drive circuit for an apparatus according to various embodiments of the present disclosure. As described above, the front-end drive circuit 330 provides at least one AC signal to the first inductive isolation circuit and the second inductive isolation circuit, thereby driving the first inductive isolation circuit and the second inductive isolation circuit, respectively. As described above, the front-end drive circuit 330 may include one or more DC-to-AC inverters or one or more AC-to-AC inverters.

[0056] 3, the front-end drive circuit 330 includes a gate driver (e.g., a gate signal generator) 331 and a DC-to-AC inverter that converts a DC input into a high-frequency AC voltage using a power stage 333. The DC-to-AC inverter is coupled to at least a portion of an inductively isolated circuit 335, referred to herein as the "primary side."

[0057] As shown in Figure 3, the DC to AC inverter is a full-bridge resonant inverter implemented for the DC to AC stage. In a particular embodiment, the DC input V DDIf the input voltage is 60V, two 80V half-bridge circuits are used to form a full bridge. Each half-bridge is implemented using a GaN power stage with an integrated gate driver 331. To maintain symmetry, two capacitances in series provide the resonant capacitance. Based on printed circuit board (PCB) planner transformer parameters, as detailed below, the series leakage inductance of the primary in a specific embodiment is 1.7 microhenries (μH). To provide a series resonant frequency of 1 megahertz (MHz), the series resonant capacitance is 15 nanofarads (nF), and each capacitance is 30 nF. For each Cs, a 22 nF ceramic capacitor and an 8.2 nF ceramic capacitor may be placed in parallel. The low-voltage input signal from the timing circuit is isolated from the GaN half-bridge module using a digital isolator. Isolated 5V is provided to the dead-time and pulse circuits using a push-pull transformer driver. Tables 1 and 2 in Appendix A of the basic provisional application provide example inverter and transformer designs for isolated 5V according to various experimental embodiments, but this application is not limited thereto.

[0058] 4A-4C illustrate example inductive isolation circuits for devices according to various embodiments of the present disclosure. More specifically, FIG. 4A illustrates an example transformer PCB design 450 for both the primary winding (e.g., front-end drive side) and the secondary winding (e.g., rectifier side). It is understood that the transformer may be coupled to a coil model. The transformer comprises an air-core planar PCB transformer that provides inductive isolation. Both the inverter-side primary winding PCB design and the rectifier-side secondary winding PCB design comprise upper and lower copper and therebetween. Table 2 in Appendix A of the basic provisional application lists the geometric parameters of the transformer design.

[0059] The particular cross-section of the transformer shown in Figure 4A shows the arrangement of 3 mil (76.2 μm) thick Kapton sheets, each rated for 4.5 kV / mil dielectric strength. In a particular experimental example, as further described herein, four 3 mil (76.2 μm) Kapton sheets were used between two transformer windings to provide 54 kV of DC insulation. The top two Kapton sheets cover the bottom side of the rectifier to prevent or reduce arcing between the rectifiers when the DC-DC converters are stacked. Similarly, the bottom two Kapton sheets are bent to cover the bottom of the inverter to provide DC insulation between the inverter and the primary winding of the DC-DC converter below it in a multi-stage configuration. 2 oz (71 microns) thick copper may be used for trace implementation. Typically, thicker copper is used because the AC resistance of the transformer winding at megahertz frequencies is inversely proportional to the copper thickness. This is because currents crowding towards the inside of the copper traces at high frequencies.

[0060] In a specific experimental embodiment, the circuit board and Kapton sheet are fastened together with nylon screws and nuts. The screw holes are filled with a high-voltage insulating coating to prevent or reduce arcing through the screw holes. With this design, the resulting transformer has Lp = 7:1 μH, Ls = 99:7 μH, and k = 0:87. Figure 4B shows this coupled insulation model, and Figure 4C shows the equivalent leakage and magnetizing inductance model of the transformer.

[0061] 5A-5B show an experimental example of a multi-stage rectifier of an apparatus according to various embodiments of the present disclosure. More specifically, FIGS. 5A-5B show an example of a 20-stage cascaded class DE rectifier for a 6 kV DC output. FIG. 5A is a PCB design, and FIG. 5B is a photograph from the experimental embodiment. The 20-stage cascaded class DE rectifier shown in FIGS. 5A-5B is similar to the C class DE rectifier shown in FIG. 2B above. Bt and C BbIn a specific experimental embodiment, the DC isolation capacitor is a 33 picofarad (pF) X1Y2 capacitor. For the diode labeled D in FIG. 2B, two 240 VSi Schottky barrier diodes are connected in series as a 480 V rated rectifier. Table 3 in Appendix A of the basic provisional application lists the part numbers of the elements.

[0062] Various experimental embodiments are directed to a 60V to 6kV power converter, a 60V to 24kV power converter, a 60V to 30kV power converter, and a 60V to 35kV power converter. The rectifiers may be single stage or multi-stage cascaded. In certain experimental embodiments, the 60V to 6kV power converter may be 6 inches by 2 inches (e.g., 15cm by 5cm). The 60V to 35kV DC-DC converter is implemented by stacking six 60V to 6kV DC-DC converters, with the converters cascaded in multi-stage.

[0063] In various embodiments, the 60V to radio frequency (RF) inverter, transformer, and RF to 6 kV rectifier described above are combined to create a 60V to 6 kV DC-DC converter. An insulating varnish may be applied to the threaded holes.

[0064] Additionally, multiple 60V to 6kV DC-DC converters may be stacked in a multi-stage configuration. DC-DC converters may be stacked in four to six stages. Multiple units of 6kV rectifiers are connected in series, and 60V inverters are connected in parallel. An example of experimental dimensions for a six-stage converter is 8 inches wide x 2.5 inches long x 2 inches high (20cm x 6cm x 5cm). The weight of the converter is 188g, although embodiments are not limited thereto.

[0065] Various experimental embodiments include a power supply, probes, and an oscilloscope connected to the DC-DC converter under test. Because the experiments involve high voltages of tens of kV, special care is taken to ensure that the experimenter is not exposed to any electrical or physical hazards. The high-voltage DC-DC converter and load are grounded by a Faraday cage shorted to a nearby water pipe. Additionally, an acrylic sheet is placed between the experimenter and the high-voltage converter to prevent potential injury from flying sparks or debris in the unlikely event of a major accident. A differential probe (model number CT4079; manufactured by Elditest) capable of measuring up to ±15 kV is used. Due to the voltage capacity limitations of the probe, voltage measurements are used on one or two resistor units of the resistor chain (each unit of resistor is 1 M). The measured voltage is scaled up by a voltage division ratio to measure the end-to-end voltage applied to the resistor chain.

[0066] 6A-6C show example experimental results for a power converter according to various embodiments of the present disclosure. More specifically, FIGS. 6A-6C show example experimental results for a 60V to 6kV DC-DC converter. The converter has its output voltage peak in the switching frequency range of 0.9 to 1 MHz, and a frequency of 1.25 MHz is used to simultaneously achieve a reasonably high output voltage and a fast rise time. Using an output voltage of 6.1 kV, 37 W of power is delivered to a 1M resistor as a load.

[0067] Figure 6A shows a thermal image of a DC-DC converter with 6 kV and 36 W output after three minutes of continuous operation. More specifically, the image shown is of a 60 V to 6 kV DC-DC converter. The temperature of the planar PCB transformer increased slowly but steadily during operation, reaching 155 degrees Celsius (C) after three minutes of continuous operation, at which point the converter was shut down to avoid damaging the transformer. In a specific experimental embodiment, an FR4 substrate was used with a Tg rating of 130 degrees Celsius.

[0068] FIG. 6B shows the output voltage and inverter half-bridge output waveforms at the moment the converter is turned on, with a measured 10 to 90 percent rise time of 135 μs. The waveforms shown show the output voltage 660 (blue) and inverter half-bridge output 661 (yellow) when the converter is turned on, with a horizontal scale of 50 μs / div and a vertical scale of 1 kV / div. FIG. 6C shows the converter's 0 to 6 kV pulsed operation, for example. The steady-state output voltage is 6.08 kV, and the DC-to-DC efficiency is 81 percent.

[0069] Various experiments are conducted on a multi-stage 60V to 24kV power converter, a 60V to 30kV power converter, and a 60V to 35kV DC-DC converter. In these experimental embodiments, the number of stacked DC-DC converter units ranges from 4 to 6, and the performance of each configuration is measured.

[0070] 7A-7D show examples of experimental results for different power converters according to various embodiments of the present disclosure. More specifically, FIGS. 7A-7D show output voltage waveforms for four-stage, five-stage, and six-stage cascaded converters, with steady-state output voltages measured to be 23.9 kV, 30.4 kV, and 35.0 kV. FIG. 7A shows the pulsed operation of a four-stage 60V to 24 kV DC-DC converter, with a horizontal scale of 500 μs / div and a vertical scale of 4 kV / div (voltages are scaled down at a 2:1 ratio on the screen). FIG. 7B shows the pulsed operation of a five-stage 60V to 30 kV DC-DC converter, with a horizontal scale of 500 μs / div and a vertical scale of 5 kV / div (voltages are scaled down at a 5:1 ratio on the screen). FIG. 7C shows the pulsed operation of a six-stage 60V to 35 kV DC-DC converter. The horizontal scale is 100 μs / div and the vertical scale is 6 kV / div (the voltage is scaled down at a ratio of 3:1 on the screen). Figure 7D shows the pulse operation of a six-stage 60 V to 35 kV DC-DC converter. The horizontal and vertical scales are the same as those in Figure 7C.

[0071] 8A-8B show example experimental performance results for another power converter according to various embodiments of the present disclosure. More specifically, FIGS. 8A-8B show the performance variation of a DC-DC converter stacked with different numbers of 6 kV units, FIG. 8 shows the efficiency variation, and FIG. 8B shows the rise time variation from 10 percent to 90 percent. Efficiency tended to decrease with the number of stacked units, decreasing from 82 percent for a single 6 kV unit to 73 percent for a six-stage configuration. One possible reason for this decrease in efficiency is that the high-frequency current distribution in the transformer windings due to the tight stacking of these multiple transformers is different from that of a single stage, thereby increasing conduction losses in the planar PCB transformer. The rise time of the inverted transformer tended to increase with the number of stacked units, increasing from 135 μs for a single unit to 296 μs for a six-unit cascade. This increase is primarily due to the regulated capacitance between the primary and secondary windings of the transformer, which charges to half the voltage of the DC-DC converter output when the converter is turned on.

[0072] As noted above, the above-described devices can be implemented in a variety of systems and other devices. Example systems include CT scanner gantries, ion sources (e.g., X-ray sources for medical imaging, linear accelerators, neutron generators for explosive detection, drill head imaging for oil logging and geological exploration), electrostatic adhesion (e.g., portable high-voltage power supplies enabling electrostatic adhesion applications such as material processing, robotic grippers, and drone parking), TWT power supplies, electrostatic filters, electrostatic spraying (e.g., using large electric fields to ionize particles for adhesion in coating applications), electrohydrodynamic propulsion (e.g., using large electric fields to ionize and accelerate air to generate thrust for aeronautical propulsion), high-power laser power supplies, tasers, particle accelerators, plasma generators (e.g., for controlling surfaces and regulating airflow in aerodynamics), capacitor charging, and ozone generators.

[0073] 9 shows an example of a computed tomography (CT) scanner gantry with devices according to various embodiments of the present disclosure. The CT scanner gantry 970 includes one or more of the above devices forming part of a high-voltage generator 972. A CT scanner gantry utilizing the above power conversion devices is smaller, lighter, and allows for faster gantry rotation 971 than other solutions. Faster rotation reduces radiation dose to the patient. Using a CT scanner gantry according to various embodiments results in a reduced radiation dose to the patient.

[0074] 10 illustrates an example of a traveling wave tube (TWT) radar power supply, according to various embodiments of the present disclosure. A TWT radar power supply utilizing the above-described apparatus 1080 can reduce its size, allowing powerful radar systems that were previously too large due to their system size and weight to be used in mobile applications or mounted in smaller vehicles (e.g., drones, automobiles, etc.). The apparatus 1080 includes a TWT 1081 and an HV source 1082 that includes the above-described power converter.

[0075] Embodiments herein are not limited to the specific example systems and / or methods illustrated by FIGS. 9-10, and Appendices B and C provide example systems and / or methods comprising power conversion that can be used in various specific embodiments.

[0076] As described herein, various embodiments are directed to a multi-stage class DE rectifier circuit with inductive isolation. High frequency operation enables fast transient response in the output voltage. An input-parallel, output-series configuration using an air-core PCB transformer with high DC voltage isolation results in a high output voltage for the DC-DC converter. Specific experimental embodiments demonstrate a 60V to 6kV DC-DC converter at a 1.25MHz switching frequency capable of delivering 36W of power to a load, and a high-gain DC-DC converter in a multi-stage configuration capable of delivering 35kV voltage and 203W of power to a load while maintaining 73 percent efficiency, and pulsing the output with a rise time of 296 microseconds (μs).

[0077] Various embodiments are implemented by the basic provisional application entitled "Apparayusses and Methods Involving a Power Converter that Includes a Multi-Stage Rectifier" (Ser. No. 62 / 639,865), filed March 7, 2018, and its three appendices, the benefit of which is claimed and which are incorporated herein by reference in their entirety. For example, the embodiments in this specification and / or the basic provisional application (including its appendices) may be combined to different degrees (including entirely). Reference may also be made to the experimental teachings and basic references provided in the basic provisional application, including any appendices that form part of the provisional application. The embodiments described in the appendices do not in any way limit the entire technical disclosure or any portion of the claimed invention, unless specifically stated otherwise.

[0078] The appendices to the basic provisional application are fully incorporated by reference for their general and specific disclosures. Appendix A, entitled "60 V-to-35 kV Input-Parallel Output-Series DC-DC Converter Using Multi-Level Class-DE Rectifiers," describes generally and specifically various power converters, rectifiers, multi-stage rectifier stacks, inverters, and methods of use thereof as illustrated herein. Appendix B, entitled "High-Voltage-High-Gain DC-DC Converter with Inductive Isolation for Multi-Level Cascade of Class-DE Rectifiers," describes generally and specifically applications of power converters as illustrated herein. Appendix C, entitled "High Voltage Generator," describes generally and specifically the use and application of power converters comprising high-voltage generators as illustrated herein. These documents are fully incorporated by reference herein for the general and specific teachings of the structures, processes, methods, and uses illustrated and described therein (including the background references cited therein, which are useful applications to aspects of the present disclosure).

[0079] Various blocks, modules, or other circuits may be implemented to perform one or more of the operations and activities described herein and / or illustrated in the figures. In these contexts, a "block" (sometimes also referred to as a "logic circuit" or "module") is a circuit for performing one or more of these or related operations / activities (e.g., as illustrated in one or more blocks or circuit elements shown in FIG. 1). For example, in certain of the above-described embodiments, one or more modules, such as the circuit modules shown in FIG. 1, are discrete logic circuits or programmable logic circuits configured and arranged to implement these operations / activities. In certain embodiments, such programmable circuits are one or more computer circuits programmed to execute a set (or sets) of instructions (and / or configuration data). The instructions (and / or configuration data) may be in the form of firmware or software stored in and accessible from memory. As an example, the first module and the second module include a combination of sets of instructions in the form of CPU hardware-based circuit firmware, where the first module is a first CPU hardware circuit with one set of instructions and the second module is a second CPU hardware circuit with another set of instructions.

[0080] Certain embodiments are directed to a computer program product (e.g., non-volatile memory) that includes a machine- or computer-readable medium that stores instructions that are executed by a computer (or other electronic device) to perform its operations / activities.

[0081] Based on the above description and illustrations, it will be apparent to those skilled in the art that various modifications and variations can be made without strictly adhering to the exemplary embodiments and applications described and illustrated herein. For example, various image processing circuits described herein may be implemented. Also, various embodiments described herein may be combined into specific embodiments, and various aspects of individual embodiments may be implemented as separate embodiments. Such variations do not depart from the true spirit and scope of the various aspects of the disclosure, including the aspects set forth in the claims.

Claims

1. a direct current to alternating current (AC) inverter circuit configured to invert at least one direct current (DC) input signal corresponding to an input voltage into at least one alternating current (AC) signal; a first circuit including a first inductive isolation circuit responsive to power from the at least one AC signal and including a first rectifier circuit responsive to the first inductive isolation circuit by outputting a first rectified signal on a first pair of output terminals; a second circuit including a second inductively isolated circuit responsive to power from the at least one AC signal and including a second rectifier circuit responsive to the second inductively isolated circuit by outputting a second rectified signal on a second pair of output terminals, at least one of the first rectifier circuit and the second rectifier circuit being limited by a voltage breakdown rating; an output circuit constructed and arranged to provide a DC output voltage signal between voltage source terminals, and cascade a plurality of signals including the first rectified signal and the second rectified signal, with one of the output terminals of one of the pair of output terminals being a source of supply to one of the other output terminals of the pair of output terminals, the voltage source terminal providing a voltage source slaved to the first rectified signal and the second rectified signal and greater than the voltage breakdown rating of at least one of the first rectifier circuit and the second rectifier circuit; An apparatus comprising:

2. 2. The apparatus of claim 1 , wherein at least one of the first inductive isolation circuit and the second inductive isolation circuit is associated with a different voltage breakdown rating that is greater than the voltage breakdown rating of at least one of the first rectifier circuit and the second rectifier circuit.

3. 2. The apparatus of claim 1, wherein at least one of the first rectifier circuit and the second rectifier circuit is constructed and arranged to provide a DC output voltage signal for the associated rectified signal that is greater than twice the voltage breakdown rating of at least one of the first rectifier circuit and the second rectifier circuit.

4. 2. The apparatus of claim 1, wherein the first inductive isolation circuit and the second inductive isolation circuit each comprise an air core transformer having an associated voltage breakdown rating that is greater than the voltage breakdown rating of at least one of the first rectifier circuit and the second rectifier circuit and defines a minimum overall voltage breakdown rating for circuits included in the first inductive isolation circuit and the second inductive isolation circuit.

5. 2. The apparatus of claim 1, wherein the voltage breakdown rating is defined by a DC isolation capacitor used in the signal path of one of the first circuit and the second circuit between the output terminal of the inductive isolation circuit and a diode of the rectifier circuit.

6. The apparatus of claim 1 , wherein the first rectifier circuit and the second rectifier circuit each include or are configured as a class DE rectifier.

7. further comprising an additional rectifier circuit having an output cascaded to the first rectifier circuit and the second rectifier circuit; each of the rectifier circuits includes or is configured as a class DE rectifier, is galvanically isolated from the input voltage, and is rated for 300 volts or greater; 10. The apparatus of claim 1.

8. a third circuit including a third inductive isolation circuit responsive to power from the at least one AC signal and a third rectifier circuit responsive to the third inductive isolation circuit by outputting a third rectified signal on a third pair of output terminals; the output circuit provides a DC output voltage signal between voltage source terminals and cascades a plurality of signals including the first rectified signal, the second rectified signal, and the third rectified signal by coupling a selected one of the output terminals of the first pair, the second pair, and the third pair of output terminals as a cascaded source of power to the first voltage source terminal, the second voltage source terminal, and the third voltage source terminal collectively arranged to provide a voltage source slaved to the first rectified signal, the second rectified signal, and the third rectified signal and greater than the voltage breakdown rating; 10. The apparatus of claim 1.

9. 2. The apparatus of claim 1, wherein each of the first rectifier circuit and the second rectifier circuit is one of a plurality of rectifier stages connected in parallel.

10. providing at least one alternating current (AC) signal from a direct current (DC) voltage input signal; using parallel first and second circuits, each providing inductive isolation, driving in response to power from the at least one AC signal, and rectifying in response to the inductive isolation by outputting a rectified signal at an associated pair of output terminals, wherein the rectification associated with at least one of the first and second circuits is limited by a voltage breakdown rating; providing a DC output voltage signal between voltage source terminals by cascading a plurality of signals including the rectified signal to a DC output voltage signal slaved to a second rectified signal and greater than the voltage breakdown rating; A method for providing

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