Dynamically configurable isolated rectifier bridges

Abstract

A configurable rectifier for a poly-phase generator. The rectifier may have multiple windings for multiple phases of current. The rectifier may include at least two rectifier bridges. The rectifier bridges may be connected in parallel in a first position and may be connected in series in a second position.

Description

Attorney Docket No.061754-1400205 Client Ref. No. B-028968PCT01 DYNAMICALLY CONFIGURABLE ISOLATED RECTIFIER BRIDGES FIELD OF THE INVENTION

[0001] This invention relates to power generation, and in particular, to dynamically configurable individually isolated rectifier bridges for power generation systems. BACKGROUND

[0002] Aircraft often power their electrical systems with generators attached to engines. The speed of aircraft engines can vary greatly depending on the operating context. For instance, aircraft turbine engines may run at much lower speeds during ground idle than during takeoff. Because aircraft turbine engines speed can vary so greatly, the available output voltage and power of the driven generators, which varies proportionally, can also vary greatly. Large variations in generator voltage output can create challenges for creating a lightweight machine that provides usable power over the speed range. Consequently, new solutions are needed. SUMMARY

[0003] The terms “invention,” “the invention,” “this invention” and “the present invention” used in this patent are intended to refer broadly to all the subject matter of this patent and the patent claims below. Statements containing these terms should be understood not to limit the subject matter described herein or to limit the meaning or scope of the patent claims below. Aspects of the invention covered by this patent are defined by the claims below, not this summary. This summary is a high-level overview of various aspects of the invention and introduces some of the concepts that are further described in the Detailed Description section below. This summary is not intended to identify key or essential features of the claimed subject matter, nor is it intended to be used in isolation to determine the scope of the claimed subject matter. The subject matter should be understood by reference to appropriate portions of the entire specification of this patent, any or all drawings and each claim.

[0004] In an example, a system includes configurable rectifier bridges for a poly-phase electric generator. The system includes a first stator winding and a second stator winding associated with a first phase of the electric generator. The system further includes a third stator winding and a fourth stator winding associated with a second phase of the electric generator. The system further includes a fifth stator winding and a sixth stator winding associated with a 1 US2008225041042Attorney Docket No.061754-1400205 Client Ref. No. B-028968PCT01 third phase of the electric generator. The system further includes a three-phase rectifier circuit. The three-phase rectifier circuit includes a first rectifier bridge connected to the first stator winding, the second stator winding, and the third stator winding. The three-phase rectifier circuit includes a second rectifier bridge connected to the fourth stator winding, the fifth stator winding, and the sixth stator winding. The three-phase rectifier circuit includes switches configured to control the three-phase rectifier circuit. When in respective first positions, the switches connect the first rectifier bridge to a DC output, connect the first rectifier bridge in series with the second rectifier bridge, and connect the second rectifier bridge to the DC output. When in respective second positions, the switches connect the first rectifier bridge to the DC output, connect the first rectifier bridge in parallel with the second rectifier bridge, and connect the second rectifier bridge to the DC output.

[0005] In an example, a method of controlling a rectifier for a poly-phase electric generator is disclosed. The method includes receiving an input signal representing a speed of a generator. The method further includes, when the input signal represents a first turbine speed below a threshold, connecting a first rectifier bridge in series with a second rectifier bridge. The first rectifier bridge is connected to a first stator winding, a second stator winding, and a third stator winding of a poly-phase electric generator. The second rectifier bridge is connected to a fourth stator winding, fifth stator winding, and sixth stator winding. The method further includes outputting a first rectified direct current voltage from the first rectifier bridge and the second rectifier bridge. The method further includes, when the input signal represents a second turbine speed above a threshold, connecting the first rectifier bridge in parallel with the second rectifier bridge and outputting a second rectified direct current voltage from the first rectifier bridge and the second rectifier bridge. BRIEF DESCRIPTION OF THE DRAWINGS

[0006] Figure 1 depicts a configurable rectifier system for a poly phase generator, in accordance with certain aspects.

[0007] Figure 2 depicts connection of stator windings to diodes of rectifier bridges, in accordance with certain aspects.

[0008] Figure 3 depicts a parallel connection of rectifier bridges, in accordance with certain aspects.

[0009] Figure 4 depicts a series connection of rectifier bridges, in accordance with certain aspects. 2 US2008225041042Attorney Docket No.061754-1400205 Client Ref. No. B-028968PCT01

[0010] Figure 5 depicts a method of reconfiguring a configurable rectifier system for a poly phase generator, in accordance with certain aspects.

[0011] Figure 6 illustrates computing environment used to implement certain functions, according to an aspect. DETAILED DESCRIPTION

[0012] The subject matter of aspects of the present disclosure is described here with specificity to meet statutory requirements, but this description is not necessarily intended to limit the scope of the claims. The claimed subject matter may be embodied in other ways, may include different elements or steps, and may be used in conjunction with other existing or future technologies. This description should not be interpreted as implying any particular order or arrangement among or between various steps or elements except when the order of individual steps or arrangement of elements is explicitly described.

[0013] Certain aspects relate to systems of reconfigurable rectifier bridges for use in power generation systems, particularly engine-mounted aircraft electrical power systems. But while these aspects are discussed for use with engines in aircraft, they are by no means so limited. Rather, disclosed systems may be used with any suitable power-generating application.

[0014] A high pressure spool of a turbine can vary as much as 2:1 from a highest to a lowest speed and a low pressure spool can vary as much as 5:1 from a highest to a lowest speed. Given that an output voltage of a generator is proportional to the speed of the rotor, given the wide range of speeds, outputting a constant voltage from a generator becomes difficult and beyond what can be done by adjusting the excitation of the generator windings. Adding windings or increasing size of the generator is undesirable because it adds unnecessary weight to the aircraft.

[0015] Disclosed solutions overcome these limitations by using dynamically configurable rectifier bridges that can change from a series configuration at low-speed operation to a parallel configuration at high-speed operation. In a more specific example, a generator is powered from a turbine. Within the generator, two or more rectifier bridges (full wave rectifiers) are configured in a series configuration. Each rectifier bridge is connected to a wye connected three-phase stator winding, each windings representing a respective isolated winding of the generator. As the engine speed increases from idle and passes a threshold speed, a controller switches the rectifier bridges to be connected in a parallel configuration. 3 US2008225041042Attorney Docket No.061754-1400205 Client Ref. No. B-028968PCT01 Conversely, when the engine speed decreases beyond the threshold, the controller switches the rectifier bridges back to the series configuration.

[0016] Turning now to the figures, Figure 1 depicts a configurable rectifier system for a poly phase generator, in accordance with certain aspects. The configurable rectifier system includes a generator 101, a switchable bridge circuit 103, and a direct current output 105. In the example depicted in Figure 1, generator 101 is connected to switchable bridge circuit 103, which includes two or more rectifier bridges configurable in series or parallel. In turn, the switchable bridge circuit 103 outputs direct current via direct current output 105. An example voltage output from output 105 is 270 VDC.

[0017] Generator 101 includes isolated stator windings. Different numbers and configurations of generator windings are possible. In some examples, generator 101 may be wound in a 2x3, 3x3, or 4x3 phase configuration. In a 2x3 configuration, generator 101 is wound with two isolated 3-phase windings. In a 3x3 configuration, generator 101 is wound with three isolated 3-phase windings. In a 4x3 configuration, generator 101 is wound with four isolated 3-phase windings. The windings of generator 101 are connected to switchable rectifier bridge 103.

[0018] Switchable rectifier bridge 103 includes two or more full wave rectifier bridges, depending on the configuration of generator 101. For example, in a configuration in which each phase has two windings, two rectifier bridges are needed. Each rectifier bridge receives all three phases. The rectifier bridges are reconfigured from series to parallel such that the parallel configuration is used with a turbine operating at high-speed and a series configuration is used when the turbine is operating at low-speed. The generator 101 may be mounted at the nose end of a turbine engine air inlet.

[0019] Example rectifier bridges are discussed further with respect to Figure 2. The rectifier bridges are reconfigurable with respect to each other on a dynamic basis, for example, based on a speed of a turbine driving the generator. The reconfiguration can employ solid state switches, relays, or other types of remote controlled switches. Figure 3 depicts an example of a parallel configuration while Figure 4 depicts an example of a series configuration. An example of a method of reconfiguring the rectifier bridges is shown with respect to Figure 5.

[0020] Figure 2 depicts connection of stator windings to diodes of rectifier bridges, in accordance with certain aspects. Figure 2 depicts circuits 200a-b. Each circuit 200a-b includes a respective set of windings 231a-b and a rectifier bridge 233a-b. While only two circuits are 4 US2008225041042Attorney Docket No.061754-1400205 Client Ref. No. B-028968PCT01 depicted, any number of circuits 200a-b is possible. Each rectifier bridge 233a-b includes multiple diodes that perform rectification of signals from three phases.

[0021] As depicted, the set of windings 231a includes stator windings 201a, 203a, and 205a, each representing a phase of the generator. Continuing the example, set of windings 231b includes stator windings 201b, 203b, and 205b, each representing one of the three phases. Additional sets of windings are possible.

[0022] In the example configuration with two sets of windings, a first stator winding 201a is associated with a first phase of an electric generator. The first stator winding 201a connects to a node 221a of rectifier bridge 233a, between diode 207a and diode 213a. A third stator winding 203a is associated with a second phase of the electric generator. The third stator winding 203a connects to a node 223a of rectifier bridge 233a, between diode 209a and 215a. A fifth stator winding 205a is associated with a third phase of the electric generator. The fifth stator winding 205a connects to a node 225a of rectifier bridge 233a, between diode 211a and 217a.

[0023] Continuing the example, second stator winding 201b is also associated with the first phase of an electric generator. The second stator winding 201b connects to a node 221b of rectifier bridge 233b, between diode 207b and diode 213b. A fourth stator winding is also associated with a second phase of the electric generator. The fourth stator winding connects to a node 223b of rectifier bridge 233b, between diode 209b and 215b. A sixth stator winding is also associated with a third phase of the electric generator. The sixth stator winding connects to a node 225b of rectifier bridge 233b, between diode 211b and 217b.

[0024] In an example, the three phases are 120 degrees out-of-phase with each other. Additionally, the windings corresponding to different rectifier bridges can be out of phase by an additional amount. These additional amounts help reduce output ripple. In the case of a 2x3- phase configuration, the additional amount is typically 30 degrees. In the case of 3x3-phase, the additional amount is typically 20 degrees. In the case of 4x4-phase, the additional amount is typically 15 degrees.

[0025] For example, the fourth stator winding can be out of phase as compared to the first stator winding by the additional amount. Similarly, fifth stator winding can be out of phase as compared to the second stator winding by the additional amount. The sixth stator winding also can be out of phase as compared to the third stator winding by the additional amount. 5 US2008225041042Attorney Docket No.061754-1400205 Client Ref. No. B-028968PCT01

[0026] The rectifier bridges depicted herein can be configured in a parallel configuration, e.g., as depicted in Figure 3, or a series configuration, e.g., as depicted in Figure 4.

[0027] Figure 3 depicts a parallel connection of rectifier bridges, in accordance with certain aspects. Figure 3 depicts rectifier bridges 321a, 321b, and 321c. The rectifier bridges 321a-c are connected in parallel, joined to a positive terminal 311 by buses 307a-c and joined to a negative terminal 313 by buses 309a-c. Rectifier bridges 321a-c may be switched to the depicted parallel configuration by one or more switches connecting or disconnecting buses 307a-c. The switches can be controlled by a processor, such as processor 602, receiving a control signal indicating a turbine is above a speed threshold, or a switch-over point.

[0028] The rectifier bridge 321a includes nodes 301a, 303a, and 305a, each of which may be connected to a stator winding having a corresponding phase. The rectifier bridge 321b includes nodes 301b, 303b, and 305b, each of which may be connected to a stator winding having a corresponding phase. The rectifier bridge 321c includes nodes 301c, 303c, and 305c, each of which may be connected to a stator winding having a corresponding phase.

[0029] Figure 4 depicts a series connection of rectifier bridges, in accordance with certain aspects. Figure 4 depicts rectifier bridges 421a-c, which are connected via buses 407, 409, 411 and 413. As depicted, first rectifier bridge 421a is in series between bus 407 and bus 409, which is in turn in series with rectifier bridge 421b, which is in series with bus 411. Bus 411 is in series with rectifier bridge 421c, and bus 413. In series, the three rectifier bridges connect to a positive terminal 415 by bus 407 and a negative terminal 417 by bus 413. In some aspects, the three bridges may be switched to the present series configuration by a controller receiving a control signal indicating a turbine is beneath a speed threshold.

[0030] The first rectifier bridge 421a includes nodes 403a, 405a, and 407a, which may be connected to three phases of a first stator, where each phases may be offset by 120 degrees from each other. The second rectifier bridge 421b includes nodes 403b, 405b, and 407b, which may be connected to three phases of a second stator. The third rectifier bridge 421c includes nodes 403c, 405c, and 407c, which may be connected to three phases of a third stator.

[0031] As discussed, the rectifier bridges discussed herein can be configured in a parallel or series configuration. For example, switches can be employed to reconfigure busses 307a-c and 309a-c to busses 401, 409, 411, and 413 and vice versa. Figure 5 depicts a method for one such reconfiguration. 6 US2008225041042Attorney Docket No.061754-1400205 Client Ref. No. B-028968PCT01

[0032] Figure 5 depicts a method 500 of reconfiguring a configurable rectifier system for a poly phase generator, in accordance with certain aspects. Method 500 involves controlling switches such that the busses described with respect to Figures 3 and 4 are reconfigured.

[0033] Any suitable computing system or device may be used for performing the operations described herein such as implementing the functions described with respect to method 500. Further, the operations described in method 500 can be supplemented with additional operations, certain operations can be skipped, and / or certain operations can be performed out of order. For illustrative purposes, method 500 is discussed as implemented via computing environment 600.

[0034] At block 501 the method involves receiving an input signal representing a speed or a frequency, for instance, of a turbine or a generator rotor. The input may be received by a controller. The speed of the turbine can be derived from the speed of the generator rotor.

[0035] At block 503, the method includes, when the input signal represents a first speed that is below a threshold, connecting a first rectifier bridge in series with a second rectifier bridge and outputting a first rectified direct current voltage from the first and second rectifier bridge. In examples in which the rectifier bridge includes a third or fourth rectifier bridge, the third or fourth rectifier bridge also may be connected in series with the first and second rectifier bridge in response to the detection. Connecting all rectifier bridges in series may result from the switches of the rectifier circuit conforming to a first position.

[0036] For example, at block 503, processor 602 causes switches, e.g., solid state switches, remote controlled switches, or relay switches to reconfigure busses 307a-c and 309a- c to busses 401, 409, 411, and 413 and vice versa. In such an example, bus 307a switches to become bus 401, two buses 309a and 307b switch to become one, single bus 409, two buses 309b and 307c switch to become one, single bus 411, and bus 309c switches to become bus 413.

[0037] At block 505, the method includes, when the input signal represents a second speed above the threshold, connecting the first rectifier bridge in parallel with a second rectifier bridge and outputting a second rectified direct current voltage from the first rectifier bridge and the second rectifier bridge. In examples where the rectifier bridge includes a third or fourth rectifier bridge, the third or fourth rectifier bridge may be connected in parallel with the first and second rectifier bridge also. Connecting all rectifier bridge in parallel may result from a plurality of switches of the rectifier circuit conforming to a second position. 7 US2008225041042Attorney Docket No.061754-1400205 Client Ref. No. B-028968PCT01

[0038] For example, at block 505, processor 602 causes the switches to reconfigure buses 401, 409, 411, and 413 to busses 307a-c and 309a-c. In such an example, bus 401 becomes bus 307a, bus 409 switches to become the two busses 309a and 307b, bus 411 switches to become two busses 309b and 307c, and bus 413 switches to become bus 309c.

[0039] To avoid unnecessary switching, the speed threshold which causes the rectifier bridges to enter the first positions may be lower than the speed threshold which causes the rectifier bridges to enter the second position. For example, at 2600 RPM, the speed threshold to enter the first position may be triggered. The speed may increase to 6000 RPM, which may cause the second speed threshold to trigger the second positions. In this manner, the thresholds form a hysteresis-like relationship between speed and switching.

[0040] Figure 6 illustrates computing environment 600 used to implement certain functions, according to an aspect. The depicted computing device 601 includes a processor 602 communicatively coupled to one or more memory devices 604. The processor 602 executes computer-executable program code 630 stored in a memory device 604, accesses data 620 stored in the memory device 604, or both. Examples of the processor 602 include a microprocessor, an application-specific integrated circuit (“ASIC”), a field-programmable gate array (“FPGA”), or any other suitable processing device. The processor 602 can include any number of processing devices or cores, including a single processing device. The functionality of the computing device may be implemented in hardware, software, firmware, or a combination thereof.

[0041] The memory device 604 includes any suitable non-transitory computer-readable medium for storing data, program code, or both. A computer-readable medium can include any electronic, optical, magnetic, or other storage device capable of providing a processor with computer-readable instructions or other program code. Non-limiting examples of a computer- readable medium include a flash memory, a ROM, a RAM, an ASIC, or any other medium from which a processing device can read instructions. The instructions may include processor- specific instructions generated by a compiler or an interpreter from code written in any suitable computer-programming language, including, for example, C, C++, C#, Visual Basic, Java, or scripting language.

[0042] The computing device 601 may also include a number of external or internal devices, such as input or output devices. For example, the computing device 601 is shown with one or more input / output (“I / O”) interfaces 608. An I / O interface 608 can receive input from input devices or provide output to output devices. One or more busses 606 are also included in 8 US2008225041042Attorney Docket No.061754-1400205 Client Ref. No. B-028968PCT01 the computing device 601. The bus 606 communicatively couples one or more components of a respective one of the computing device 601.

[0043] The computing device 601 executes program code 630 that configures the processor 602 to perform one or more of the operations described herein. For example, the program code 630 causes the processor to perform the operations described in Figures 3.

[0044] The computing device 601 also includes a network interface device 610. The network interface device 610 includes any device or group of devices suitable for establishing a wired or wireless data connection to one or more data networks. The network interface device 610 may be a wireless device and have an antenna 614. The computing device 601 can communicate with one or more other computing devices implementing the computing device or other functionality via a data network using the network interface device 610.

[0045] The computing device 601 can also include a display device 612. Display device 612 can be a LCD, LED, touch-screen or other device operable to display information about the computing device 601.

[0046] In the following, further examples are described to facilitate the understanding of the disclosure: Example A. A configurable rectifier for a poly-phase electric generator, the rectifier comprising a first stator winding and a second stator winding associated with a first phase of the electric generator; a third stator winding and a fourth stator winding associated with a second phase of the electric generator; a fifth stator winding and a sixth stator winding associated with a third phase of the electric generator; a three-phase rectifier circuit comprising: a first rectifier bridge connected to the first stator winding, the second stator winding, and the third stator winding; a second rectifier bridge connected to the fourth stator winding, the fifth stator winding, and the sixth stator winding; and a plurality of switches configured to control the three-phase rectifier circuit, wherein: when in respective first positions, the switches: connect the first rectifier bridge to a DC output; connect the first rectifier bridge in series with the second rectifier bridge; and connect the second rectifier bridge to the DC output; when in respective second positions, the switches: connect the first rectifier bridge to the DC output; connect the first rectifier bridge in parallel with the second rectifier bridge; and connect the second rectifier bridge to the DC output. 9 US2008225041042Attorney Docket No.061754-1400205 Client Ref. No. B-028968PCT01 Example B. The configurable rectifier bridge of any preceding or subsequent examples, wherein the first stator winding is out of phase with the second stator winding by twenty degrees; the third stator winding is out of phase with the fourth stator winding by twenty degrees; and fifth stator winding is out of phase with the sixth stator winding by twenty degrees. Example C. The configurable rectifier of any preceding or subsequent examples, wherein each rectifier bridge comprises three pairs of diodes, wherein each pair of diodes is connected to a corresponding stator winding. Example D. The configurable rectifier bridge of any preceding or subsequent examples, wherein the rectifier comprises: an input for receiving a control signal; and a controller configured to receive the control signal and upon detecting that the control signal is beyond a threshold, configured to cause the switches to switch from the first positions to the second positions. Example E. The configurable rectifier of any preceding or subsequent examples, wherein the control signal represents a speed of a generator. Example F. The configurable rectifier of any preceding or subsequent examples, wherein the first positions are associated with a generator speed of less than a threshold and the second positions are associated with a generator speed of more than a threshold. Example G. A method of controlling a rectifier for a poly-phase electric generator, the method comprising: receiving an input signal representing a speed of a generator; when the input signal represents a first generator speed below a threshold: connecting a first rectifier bridge in series with a second rectifier bridge, wherein the first rectifier bridge is connected to a first stator winding, a second stator winding, and a third stator winding of a poly-phase electric generator; and a second rectifier bridge is connected to a fourth stator winding, a fifth stator winding, and the sixth stator winding of the generator; and outputting a first rectified direct current voltage from the first rectifier bridge and the second rectifier bridge; and when the input signal represents a second generator speed above a threshold: connecting the first rectifier bridge in parallel with the second rectifier bridge; and outputting a second rectified direct current voltage from the first rectifier bridge and the second rectifier bridge. Example H. The method of any preceding or subsequent examples, the first stator winding is out of phase with the second stator winding by twenty degrees; the third stator winding is out of phase with the fourth stator winding by twenty degrees; and fifth stator winding is out of phase with the sixth stator winding by twenty degrees. 10 US2008225041042Attorney Docket No.061754-1400205 Client Ref. No. B-028968PCT01 Example I. The method of any preceding or subsequent examples, wherein each rectifier bridge comprises three pairs of diodes, wherein each pair of diodes is connected to a corresponding stator winding. Example J. The method of any preceding or subsequent examples, wherein the rectifier comprises: an input for receiving a control signal; and a controller configured to receive the control signal and upon detecting that the control signal is beyond a threshold, configured to cause the switches to switch from the first positions to the second positions. Example K. The method of any preceding or subsequent examples, wherein the control signal represents a speed of a generator. Example L. The method of any preceding or subsequent examples, wherein the first positions are associated with a generator speed of less than a threshold and the second positions are associated with a generator speed of more than a threshold. Example M. An electric generator comprising: a stator comprising: a first stator winding and a second stator winding associated with a first phase of the electric generator; a third stator winding and a fourth stator winding associated with a second phase of the electric generator; a fifth stator winding and a sixth stator winding associated with a third phase of the electric generator; a DC output circuit; a three-phase rectifier circuit comprising: a first rectifier bridge connected to the first stator winding, the second stator winding, and the third stator winding; a second rectifier bridge connected to the fourth stator winding, the fifth stator winding, and the sixth stator winding; and a plurality of switches configured to control the three-phase rectifier circuit, wherein: when in respective first positions, the switches: connect the first rectifier bridge to the DC output circuit; connect the first rectifier bridge in series with the second rectifier bridge; and connect the second rectifier bridge to the DC output circuit; when in respective second positions, the switches: connect the first rectifier bridge to the DC output circuit; connect the first rectifier bridge in parallel with the second rectifier bridge; and connect the second rectifier bridge to the DC output circuit. Example B. The configurable rectifier of any preceding or subsequent examples, wherein the first stator winding is out of phase with the second stator winding by twenty degrees; the third stator winding is out of phase with the fourth stator winding by twenty degrees; and fifth stator winding is out of phase with the sixth stator winding by twenty degrees. Example N. The electric generator of any preceding or subsequent examples, wherein each rectifier bridge comprises three pairs of diodes, wherein each pair of diodes is connected to a corresponding stator winding. 11 US2008225041042Attorney Docket No.061754-1400205 Client Ref. No. B-028968PCT01 Example M. The electric generator of any preceding or subsequent examples, wherein the rectifier comprises: an input for receiving a control signal; and a controller configured to receive the control signal and upon detecting that the control signal is beyond a threshold, configured to cause the switches to switch from the first positions to the second positions. Example O. The electric generator of any preceding or subsequent examples, wherein the control signal represents a speed of a generator. Example P. The electric generator of any preceding or subsequent examples, wherein the first positions are associated with a generator speed of less than a threshold and the second positions are associated with a generator speed of more than a threshold. Example Q. The electric generator of any preceding or subsequent examples, wherein the first positions are associated with a generator speed of a first threshold and the second positions are associated with a generator speed of more than a second threshold. Example R. The configurable rectifier of any preceding or subsequent examples, wherein the first positions are associated with a generator speed of a first threshold and the second positions are associated with a generator speed of more than a second threshold.

[0047] Different arrangements of the components depicted in the drawings or described above, as well as components and steps not shown or described are possible. Similarly, some features and sub-combinations are useful and may be employed without reference to other features and sub-combinations. Aspects of the disclosure have been described for illustrative and not restrictive purposes, and alternative aspects will become apparent to readers of this patent. Accordingly, the present disclosure is not limited to the aspects described above or depicted in the drawings, and various aspects and modifications may be made without departing from the scope of the claims below.

[0048] The specification and drawings are, accordingly, to be regarded in an illustrative rather than a restrictive sense. It will, however, be evident that various modifications and changes may be made thereunto without departing from the broader spirit and scope of the disclosure as set forth in the claims.

[0049] Other variations are within the spirit of the present disclosure. Thus, while the disclosed techniques are susceptible to various modifications and alternative constructions, certain illustrated examples thereof are shown in the drawings and have been described above in detail. It should be understood, however, that there is no intention to limit the disclosure to the specific form or forms disclosed, but on the contrary, the intention is to cover all 12 US2008225041042Attorney Docket No.061754-1400205 Client Ref. No. B-028968PCT01 modifications, alternative constructions and equivalents falling within the spirit and scope of the disclosure, as defined in the appended claims.

[0050] The use of the terms “a” and “an” and “the” and similar referents in the context of describing the disclosed examples (especially in the context of the following claims) are to be construed to cover both the singular and the plural, unless otherwise indicated herein or clearly contradicted by context. The terms “comprising,” “having,” “including,” and “containing” are to be construed as open-ended terms (e.g., meaning “including, but not limited to,”) unless otherwise noted. The term “connected” is to be construed as partly or wholly contained within, attached to, or joined together, even if there is something intervening. Recitation of ranges of values herein are merely intended to serve as a shorthand method of referring individually to each separate value falling within the range, unless otherwise indicated herein, and each separate value is incorporated into the specification as if it were individually recited herein. All methods described herein can be performed in any suitable order unless otherwise indicated herein or otherwise clearly contradicted by context. The use of any and all examples, or exemplary language (e.g., “such as”) provided herein, is intended merely to better illuminate examples of the disclosure, and does not pose a limitation on the scope of the disclosure unless otherwise claimed. No language in the specification should be construed as indicating any non-claimed element as essential to the practice of the disclosure.

[0051] Disjunctive language such as the phrase “at least one of X, Y, or Z,” unless specifically stated otherwise, is otherwise understood within the context as used in general to present that an item, term, etc., may be either X, Y, or Z, or any combination thereof (e.g., X, Y, and / or Z). Thus, such disjunctive language is not generally intended to, and should not, imply that certain examples require at least one of X, at least one of Y, or at least one of Z to each be present.

[0052] Use herein of the word “or” is intended to cover inclusive and exclusive OR conditions. In other words, A or B or C includes any or all of the following alternative combinations as appropriate for a particular usage: A alone; B alone; C alone; A and B only; A and C only; B and C only; and all three of A, B, and C.

[0053] Preferred examples of this disclosure are described herein, including the best mode known to the inventors for carrying out the disclosure. Variations of those preferred examples may become apparent to those of ordinary skill in the art upon reading the foregoing description. The inventors expect skilled artisans to employ such variations as appropriate, and the inventors intend for the disclosure to be practiced otherwise than as specifically described 13 US2008225041042Attorney Docket No.061754-1400205 Client Ref. No. B-028968PCT01 herein. Accordingly, this disclosure includes all modifications and equivalents of the subject matter recited in the claims appended hereto as permitted by applicable law. Moreover, any combination of the above-described elements in all possible variations thereof is encompassed by the disclosure unless otherwise indicated herein or otherwise clearly contradicted by context.

[0054] All references, including publications, patent applications, and patents, cited herein are hereby incorporated by reference to the same extent as if each reference were individually and specifically indicated to be incorporated by reference and were set forth in its entirety herein. 14 US2008225041042

Claims

Attorney Docket No.061754-1400205 Client Ref. No. B-028968PCT01 CLAIMS What is claimed is:

1. A system of configurable rectifier bridges for a poly-phase electric generator, the system comprising: a first stator winding and a second stator winding associated with a first phase of the electric generator; a third stator winding and a fourth stator winding associated with a second phase of the electric generator; a fifth stator winding and a sixth stator winding associated with a third phase of the electric generator; a three-phase rectifier circuit comprising: a first rectifier bridge connected to the first stator winding, the second stator winding, and the third stator winding; a second rectifier bridge connected to the fourth stator winding, the fifth stator winding, and the sixth stator winding; and a plurality of switches configured to control the three-phase rectifier circuit, wherein: when in respective first positions, the switches: connect the first rectifier bridge to a DC output; connect the first rectifier bridge in series with the second rectifier bridge; and connect the second rectifier bridge to the DC output; when in respective second positions, the switches: connect the first rectifier bridge to the DC output; connect the first rectifier bridge in parallel with the second rectifier bridge; and connect the second rectifier bridge to the DC output.

2. The rectifier of claim 1, wherein: the first stator winding is out of phase with the second stator winding by twenty degrees; the third stator winding is out of phase with the fourth stator winding by twenty degrees; and 15 US2008225041042Attorney Docket No.061754-1400205 Client Ref. No. B-028968PCT01 fifth stator winding is out of phase with the sixth stator winding by twenty degrees.

3. The rectifier of claim 1, wherein each rectifier bridge comprises three pairs of diodes, wherein each pair of diodes is connected to a corresponding stator winding.

4. The generator of claim 1, wherein the rectifier comprises: an input for receiving a control signal; and a controller configured to receive the control signal and upon detecting that the control signal is beyond a threshold, cause the switches to switch from the first positions to the second positions.

5. The generator of claim 1, wherein the control signal represents a speed of a generator .

6. The generator of claim 1, wherein the first positions are associated with a generator speed of less than a threshold and the second positions are associated with a turbine speed of more than the threshold.

7. The generator of claim 1, wherein the first positions are associated with a generator speed of a first threshold and the second positions are associated with a generator speed of more than a second threshold that is different than the first threshold.

8. A method of controlling a rectifier for a poly-phase electric generator, the method comprising: receiving an input signal representing a speed of a generator ; when the input signal represents a first generator speed below a threshold: connecting a first rectifier bridge in series with a second rectifier bridge, wherein the first rectifier bridge is connected to a first stator winding, a second stator winding, and a third stator winding of a poly-phase electric generator; and the second rectifier bridge is connected to a fourth stator winding, a fifth stator winding, and a sixth stator winding of the generator; and outputting a first rectified direct current voltage from the first rectifier bridge and the second rectifier bridge; and 16 US2008225041042Attorney Docket No.061754-1400205 Client Ref. No. B-028968PCT01 when the input signal represents a second generator speed above a threshold: connecting the first rectifier bridge in parallel with the second rectifier bridge; and outputting a second rectified direct current voltage from the first rectifier bridge and the second rectifier bridge.

9. The method of claim 8, wherein: the first stator winding is out of phase with the second stator winding by twenty degrees; the third stator winding is out of phase with the fourth stator winding by twenty degrees; and fifth stator winding is out of phase with the sixth stator winding by twenty degrees.

10. The method of claim 8, wherein each rectifier bridge comprises three pairs of diodes, wherein each pair of diodes is connected to a corresponding stator winding.

11. The method of claim 9, wherein the rectifier comprises: an input for receiving a control signal; and a controller configured to receive the control signal and upon detecting that the control signal is beyond a threshold, configured to cause the switches to switch from the first positions to the second positions.

12. The method of claim 9, wherein the control signal represents a speed of a generator.

13. The method of claim 9, wherein the first positions are associated with a generator speed of less than a threshold and the second positions are associated with a generator speed of more than the threshold.

14. An electric generator comprising: a stator comprising: a first stator winding and a second stator winding associated with a first phase of the electric generator; 17 US2008225041042Attorney Docket No.061754-1400205 Client Ref. No. B-028968PCT01 a third stator winding and a fourth stator winding associated with a second phase of the electric generator; and a fifth stator winding and a sixth stator winding associated with a third phase of the electric generator; a DC output circuit; a three-phase rectifier circuit comprising: a first rectifier bridge connected to the first stator winding, the second stator winding, and the third stator winding; a second rectifier bridge connected to the fourth stator winding, the fifth stator winding, and the sixth stator winding; and a plurality of switches configured to control the three-phase rectifier circuit, wherein: when in respective first positions, the switches connect the first rectifier bridge in series with the second rectifier bridge; and when in respective second positions, the switches connect the first rectifier bridge in parallel with the second rectifier bridge.

15. The electric generator of claim 14, wherein: the first stator winding is out of phase with the second stator winding by twenty degrees; the third stator winding is out of phase with the fourth stator winding by twenty degrees; and fifth stator winding is out of phase with the sixth stator winding by twenty degrees.

16. The electric generator of claim 14, wherein each rectifier bridge comprises three pairs of diodes, wherein each pair of diodes is connected to a corresponding stator winding.

17. The electric generator of claim 14, wherein the rectifier circuit further comprises: an input for receiving a control signal; and a controller configured to receive the control signal and upon detecting that the control signal is beyond a threshold, configured to cause the switches to switch from the first positions to the second positions. 18 US2008225041042Attorney Docket No.061754-1400205 Client Ref. No. B-028968PCT01 18. The electric generator of claim 14, wherein the control signal represents a speed of a generator.

19. The electric generator of claim 14, wherein the first positions are associated with a generator speed of less than a threshold and the second positions are associated with a generator speed of more than the threshold.

20. The electrical generator of claim 14, wherein the first positions are associated with a generator speed of a first threshold and the second positions are associated with a generator speed of more than a second threshold that is different from the first threshold. 19 US2008225041042

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