Flux-modulated electromagnetic apparatus

Abstract

A flux-modulated electromagnetic apparatus includes an induction machine including a rotor and a stator surrounding the rotor. The rotor includes a core and a rotor winding including a plurality of metal bars in contact with an outer surface of the rotor or an outer surface of the core. The stator includes slots, a power winding, a first control winding and a second control winding. The flux-modulated electromagnetic apparatus includes a first voltage source converter electrically coupled to the stator having a first AC terminal and a first DC terminal and a second voltage source converter electrically coupled to the stator having a second AC terminal and a second DC terminal. The first DC terminal is electrically coupled to the second DC terminal via a capacitor. The first AC terminal is electrically coupled to the first control winding. The second AC terminal is electrically coupled to the second control winding.

Description

FLUX-MODULATED ELECTROMAGNETIC APPARATUSTECHNICAL FIELD

[0001] The present disclosure relates generally to electromagnetic devices, and more specifically to a flux-modulated electromagnetic apparatus.BACKGROUND

[0002] Electromagnetic machines may be operated in both generator and motor modes. For many applications of electromagnetic machines, it is desirable to achieve smooth torque profiles during operation.SUMMARY

[0003] The system described in the present disclosure provides several practical applications and technical advantages that overcome the current technical problems with electromagnetic devices. In particular, some existing electromagnetic devices may exhibit torque ripples that adversely affect the performance in both motoring and generating modes.

[0004] In general, a flux-modulated electromagnetic apparatus includes an induction machine operably coupled to a power grid and a back-to-back (B2B) converter. The B2B converter is operably coupled to a control system via a network. The induction machine includes a rotor and a stator surrounding a rotor. The rotor includes a core (e.g., cylindrical laminated steel core) and a rotor winding embedded in the core at an outer surface of the rotor or an outer surface of the core. The stator includes a plurality of slots at an inner surface of the stator and a power winding, a first control winding and a second control winding extending through the plurality of slots. The rotor and the stator are spaced apart such that an air gap exists between the inner surface of the stator and the outer surface of the rotor. The power winding of the stator is operably coupled to the power grid. The B2B converter includes a first voltage source converter and a second voltage source converter operably coupled to the first voltage source converter via a capacitor. An alternating current (AC) terminal of the first voltage source converter is operably coupled to the first control winding of the stator. A direct current (DC) terminal of the first voltage source converter is operably coupled to the capacitor. An AC terminal of the second voltage source converter is operably coupled to the second controlwinding of the stator. A DC terminal of the second voltage source converter is operably coupled to the capacitor.

[0005] In operation, the control system is configured to generate one or more instructions and send the one or more instructions to the B2B converter via the network. The one or more instructions may be determined based on a current angular speed and a synchronous angular speed of the rotor of the induction machine. The one or more instructions may instruct the B2B converter to generate one or more control signals for the stator of the induction machine, such that the one or more control signals alter the synchronous angular speed and cause the synchronous angular speed to match the current angular speed. The one or more instructions may be determined and sent to the B2B converter for a desired time period, such that the synchronous angular speed matches the current angular speed for the desired time period.

[0006] By matching the synchronous angular speed to the current angular speed of the rotor of the induction machine, a torque profile of the induction machine is improved in the motor mode and an electrical signal generated by the induction machine is improved in the generator mode.

[0007] In a particular embodiment, a flux-modulated electromagnetic apparatus includes an induction machine. The induction machine includes a rotor and a stator surrounding the rotor. The rotor includes a core and a rotor winding in contact with an outer surface of the rotor or an outer surface of the core. The rotor winding includes a plurality of metal bars. The stator includes a plurality of slots at an inner surface of the stator, a power winding wrapped around the rotor and extending through a first set of the plurality of slots, a first control winding wrapped around the rotor and extending through a second set of the plurality of slots, and a second control winding wrapped around the rotor and extending through a third set of the plurality of slots. The power winding is electrically coupled to a power grid. The induction machine further includes an air gap between the inner surface of the stator and the outer surface of the rotor. The flux-modulated electromagnetic apparatus further includes a first voltage source converter electrically coupled to the stator and having a first alternating current (AC) terminal and a first direct current (DC) terminal and a second voltage source converter electrically coupled to the stator and having a second AC terminal and a second DC terminal. The first DC terminal is electrically coupled to the second DC terminal via a capacitor. The first AC terminal is electrically coupled to the first control winding. The second AC terminal is electrically coupled to the second control winding.

[0008] Certain embodiments of this disclosure may include some, all, or none of these advantages. These advantages and other features will be more clearly understood from the following detailed description taken in conjunction with the accompanying drawings and claims.BRIEF DESCRIPTION OF THE DRAWINGS

[0009] For a more complete understanding of this disclosure, reference is now made to the following brief description, taken in connection with the accompanying drawings and detailed description, where like reference numerals represent like parts.

[0010] FIG. 1 illustrates a schematic view of an embodiment of a flux-modulated electromagnetic machine apparatus;

[0011] FIG. 2 illustrates a cross-sectional view of an embodiment of an induction machine;

[0012] FIG. 3 illustrates a cross-sectional view of an embodiment of a stator with a power winding;

[0013] FIG. 4 illustrates a layout of an embodiment of a power winding;

[0014] FIG. 5 illustrates a plot of a magnetomotive force generated by an embodiment of a power winding;

[0015] FIG. 6 illustrates a harmonic analysis of a magnetomotive force generated by an embodiment of a power winding;

[0016] FIG. 7 illustrates a slot star plot of an embodiment of a power winding;

[0017] FIG. 8 illustrates a cross-sectional view of an embodiment of a stator with a first control winding;

[0018] FIG. 9 illustrates a layout of an embodiment of a first control winding;

[0019] FIG. 10 illustrates a plot of a magnetomotive force generated by an embodiment of a first control winding;

[0020] FIG. 11 illustrates a harmonic analysis of a magnetomotive force generated by an embodiment of a first control winding;

[0021] FIG. 12 illustrates a slot star plot of an embodiment of a first control winding;

[0022] FIG. 13 illustrates a cross-sectional view of an embodiment of a stator with a second control winding;

[0023] FIG. 14 illustrates a layout of an embodiment of a second control winding;

[0024] FIG. 15 illustrates a plot of a magnetomotive force generated by an embodiment of a second control winding;

[0025] FIG. 16 illustrates a harmonic analysis of a magnetomotive force generated by an embodiment of a second control winding; and

[0026] FIG. 17 illustrates a slot star plot of an embodiment of a second control winding.DETAILED DESCRIPTION

[0027] Previous technologies fail to provide an effective control mechanism for electromagnetic devices. Embodiments of the present disclosure and its advantages may be understood by referring to FIGS. 1 through 17. FIGS. 1 through 17 are used to describe a flux- modulated electromagnetic apparatus.Overview of a Flux-Modulated Electromagnetic Apparatus

[0028] FIG. 1 illustrates a schematic view of an embodiment of a flux-modulated electromagnetic apparatus 100. The flux-modulated electromagnetic apparatus 100 comprises an induction machine 102 operably coupled to a power grid 104 and a back-to-back (B2B) converter 106 via wirings 108, 110 and 112. The B2B converter 106 is operably coupled to a control system 136 via a network 134. Each of the wirings 108, 110 and 112 may comprise a three-phase wiring. In the illustrated embodiment, the flux-modulated electromagnetic apparatus 100 is configured as a wind turbine and converts wind energy into electromagnetic energy, such that the generated electromagnetic energy is delivered to the power grid 104 via the wiring 108. In such embodiments, the induction machine 102 is mechanically coupled to a gearbox 114 using a shaft 116. The shaft 116 may comprise a stainless steel and is configured to transfer mechanical energy from the gearbox 114 to the induction machine 102. The gearbox 114 is mechanically coupled to a plurality of blades 118. The B2B converter 106 comprises a first voltage source converter 120 operably coupled to a second voltage source converter 122 via a capacitor 124.

[0029] In operation, the control system 136 is configured to generate one or more instructions 146 and send the one or more instructions 146 to the B2B converter 106 via the network 134. The one or more instructions 146 may be determined based on a current angular speed and a synchronous angular speed of a rotor 202 (see FIG. 2) of the induction machine 102. The oneor more instructions 146 may instruct the B2B converter 106 to generate one or more control signals (e.g., control signals 148 and / or 150) for a stator 210 (see FIG. 2) of the induction machine 102, such that the one or more control signals alter the synchronous angular speed and cause the synchronous angular speed to match the current angular speed. The one or more instructions may be determined and sent to the B2B converter 106 for a desired time period, such that the synchronous angular speed matches the current angular speed for the desired time period.Apparatus componentsNetwork

[0030] Network 134 may be any suitable type of wireless and / or wired network. Network 134 may or may not be connected to the Internet or public network. Network 134 may include all or a portion of an Intranet, a peer-to-peer network, a switched telephone network, a local area network (LAN), a wide area network (WAN), a metropolitan area network (MAN), a personal area network (PAN), a wireless PAN (WPAN), an overlay network, a software-defined network (SDN), a virtual private network (VPN), a mobile telephone network (e.g., cellular networks, such as 4G or 5G), a plain old telephone (POT) network, a wireless data network (e.g., WiFi, WiGig, WiMax, etc.), a long-term evolution (LTE) network, a universal mobile telecommunications system (UMTS) network, a peer-to-peer (P2P) network, a Bluetooth network, a near field communication (NFC) network, and / or any other suitable network. Network 134 may be configured to support any suitable type of communication protocol as would be appreciated by one of ordinary skill in the art.Induction Machine

[0031] FIG. 2 illustrates a cross-sectional view of an embodiment of the induction machine 102. The induction machine 102 comprises a rotor 202. The rotor 202 comprises a cylindrical laminated steel core 204 and a winding 206 embedded in the core 204 or wrapped around the rotor 202. The core 204 may be a cylindrical laminated steel core. The winding 206 may be in contact with an outer surface of the rotor 202 or an outer surface of the core 204. The winding 206 comprises a plurality of metal bars 208 embedded at an outer surface of the cylindricallaminated steel core 204 or at an outer surface of the rotor 202. The metal bars 208 may extend along a cylindrical axis of the cylindrical laminated steel core 204. In the illustrated embodiment, the winding 206 comprises 30 metal bars 208. In other embodiments, a number of metal bars 208 may be chosen according to desired characteristics of the induction machine 102. The metal bars 208 may be connected to each other through an end-ring (not shown). In certain embodiments, the cylindrical laminated steel core 204 is an annular structure. In such embodiments, the shaft 116 extends through the cylindrical laminated steel core 204 and mechanically couples the rotor 202 to the gearbox 114 (see FIG. 1). The winding 206 may be also referred to as a bar cage winding or a rotor winding.

[0032] The stator 210 surrounds the rotor 202. The stator 210 comprises a cylindrical body 212. In certain embodiments, the cylindrical body 212 is an annular structure. In such embodiments, the rotor 202 extends through the cylindrical body 212 of the stator 210. The cylindrical body 212 comprise a plurality of slots 214 at an inner surface of the cylindrical body 212. Each of the slots 214 may comprise a trench in the cylindrical body 212 that extends along a cylindrical axis of the cylindrical body 212. In the illustrated embodiment, the cylindrical body 212 comprise 48 slots 214. In other embodiments, a number of slots 214 may be chosen according to desired characteristics of the induction machine 102. The stator 210 comprises windings 216, 218 and 220 wrapped around the cylindrical body 212 and extending through the plurality of slots 214. The winding 216 is placed proximate to the inner surface of the cylindrical body 212, the winding 220 is proximate to bottoms of the slots 214, and the winding 218 is interposed between the winding 216 and the winding 220. The rotor 202 and the stator 210 are spaced apart such that an air gap 222 is interposed between an outer surface of the rotor 202 and an inner surface of the stator 210. The windings 216, 218 and 220 may comprise a conductive material such as aluminum, copper, or the like. The windings 216, 218 and 220 generate a rotating magnetic field (RMF) withing the air gap 222.

[0033] The winding 216 is electrically coupled to the power grid 104 using the wiring 108 (see FIG. 1). The winding 216 may be also referred to as a power winding. The winding 220 is operably coupled to the first voltage source converter 120 of the B2B converter 106 using the wiring 110. The winding 220 may also be referred to as a first control winding. The winding 218 is operably coupled to the second voltage source converter 122 of the B2B converter 106 using the wiring 112. The winding 218 may also be referred to as a second control winding.The winding 216, 218 and 220 are electrically coupled to each other via a time-dependent electromagnetic field.

[0034] A synchronous angular speed a)rsof the rotor 202 is determined by an equation (1):

[0035] where a)s, a)D, and )Eare angular frequencies of currents (or voltages) in the windings 216, 218, and 220, respectively, and Ps, PD, and PEare pole pair numbers of the windings 216, 218, and 220, respectively. Based on the equation (1), the synchronous angular speed )rsof the rotor 202 may be controlled by controlling angular frequencies a)Dand )Eof currents (or voltages) in the windings 218 and 220, respectively, which are generated by the B2B converter 106.

[0036] A rotating magnetic field (RMF) generated by a winding (e.g., the windings 216, 218 and 220) has a phase shift a defined by an equation (2):2nP a = - ,Z

[0037] where Z is a total number of slots 214 and P is the pole pair number of the winding. The RMF generated by the winding 220 is offset by the RMFs generated by the windings 216 and 218, which may be used to control the total RMF that is applied to the winding 206 of the rotor 202 by the windings 216, 218 and 220 of the stator 210.

[0038] In operation, when an angular speed of a)rof the rotor 202 is less than the synchronous angular speed a)rs, an electrical power of the winding 220 is compensated by the winding 218 with the help of the B2B converter 106. On the other hand, when the angular speed of a)rof the rotor 202 is greater than the synchronous angular speed a)rs, the winding 206 sends an electrical power back to the winding 216 through the help of the winding 218 and 220 that are coupled to the B2B converter 106. Accordingly, the synchronous angular speed a)rsof the rotor 202 can be adjusted based on the angular speed of a)rof the rotor 202, which is driven by the shaft 116, the blades 118 and the gearbox 114. Therefore, the synchronous angular speed a)rscan be reached within a wide range of wind speed, allowing improved electrical signal being sent to the power grid 104. In addition, the B2B converter 106 can be configured to reduce high-order harmonics of an magnetomotive force (MMF) generated by the winding 216, 218 and 220.

[0039] FIG. 3 illustrates a cross-sectional view of the stator 210 with the winding 216. In certain embodiments, the winding 216 may be a three-phase winding comprising a phase A winding 302, a phase B winding 304 and a phase C winding 306. In the illustrated embodiment, the pole pair number Psof the winding 216 is 2. In other embodiments, the winding 216 may be designed such that the pole pair number Psof the winding 216 is any desired number based on desired characteristics of the induction machine 102.

[0040] FIG. 4 illustrates an embodiment of a layout 400 of the winding 216. In the illustrated embodiment, the winding 216 comprises the phase A winding 302, the phase B winding 304 and the phase C winding 306 that are star connected with one parallel path to each winding.

[0041] FIG. 5 illustrates a plot 500 of a magnetomotive force (MMF) generated by the winding 216 in the air gap 222 (see FIG. 2). The plot 500 includes a phase A MMF 502, a phase B MMF 504, a phase C MMF 506, and a total MMF 508 as a function of a location within the air gap 222 defined by a mechanical angle 224 (see FIG. 2).

[0042] FIG. 6 illustrates a harmonic analysis of the MMF generated by the winding 216 in the air gap 222 (see FIG. 2). In particular, FIG. 2 illustrates a spectrum 600 of the total MMF 508 (see FIG. 5) determined by a fast-Fourier transformation (FFT). The spectrum 600 comprises a plurality of harmonics 602. In the illustrated embodiment, high-order harmonics have less weights compared to the 1 st order harmonic 602- 1 , with a 5th order harmonic 602-5 and a 7th order harmonic 602-7 having large weights. In certain embodiments, weights of the high-order harmonics may be reduced with the help of the B2B converter 106 (see FIG. 1).

[0043] FIG. 7 illustrates a slot star plot 700 of the winding 216. The slot star plot 700 illustrates the MMF distribution generated by the winding 216. The slot star plot 700 shows that the MMF is sinusoidally distributed in the airgap 222 (see FIG. 2) such that a balanced electromagnetic signal can be produced.

[0044] FIG. 8 illustrates a cross-sectional view of the stator 210 with the winding 220. In certain embodiments, the winding 220 may be a three-phase winding comprising a phase A winding 802, a phase B winding 804 and a phase C winding 806. In the illustrated embodiment, the pole pair number PEof the winding 220 is 4. In other embodiments, the winding 220 may be designed such that the pole pair number PEof the winding 220 is any desired number based on desired characteristics of the induction machine 102.

[0045] FIG. 9 illustrates an embodiment of a layout 900 of the winding 220. In the illustrated embodiment, the winding 220 comprises the phase A winding 802, the phase B winding 804 and the phase C winding 806 that are star connected with one parallel path to each winding.

[0046] FIG. 10 illustrates a plot 1000 of a magnetomotive force (MMF) generated by the winding 220 in the air gap 222 (see FIG. 2). The plot 1000 includes a phase A MMF 1002, a phase B MMF 1004, a phase C MMF 1006, and a total MMF 1008 as a function of a location within the air gap 222 defined by the mechanical angle 224 (see FIG. 2).

[0047] FIG. 11 illustrates a harmonic analysis of the MMF generated by the winding 220 in the air gap 222 (see FIG. 2). In particular, FIG. 11 illustrates a spectrum 1100 of the total MMF 1008 (see FIG. 10) determined by a fast-Fourier transformation (FFT). The spectrum 1100 comprises a plurality of harmonics 1102. In the illustrated embodiment, high-order harmonics have less weights compared to the 1st order harmonic 1102-1, with the forty-seventh order harmonic 1102-2 having a largest weight among the high-order harmonics. In certain embodiments, weights of the high-order harmonics may be reduced with the help of the B2B converter 106 (see FIG. 1).

[0048] FIG. 12 illustrates a slot star plot 1200 of the winding 220. The slot star plot 1200 illustrates the MMF distribution generated by the winding 220. The slot star plot 1200 shows that the MMF is sinusoidally distributed in the airgap 222 (see FIG. 2) such that a balanced electromagnetic signal can be produced.

[0049] FIG. 13 illustrates a cross-sectional view of the stator 210 with the winding 218. In certain embodiments, the winding 218 may be a three-phase winding comprising a phase A winding 1302, a phase B winding 1304 and a phase C winding 1306. In the illustrated embodiment, the pole pair number PDof the winding 218 is 2. In other embodiments, the winding 218 may be designed such that the pole pair number PDof the winding 218 is any desired number based on desired characteristics of the induction machine 102. In certain embodiments, the windings 218 may have a layout similar to the winding 216 (see FIGD. 3 and 4). In such embodiments, the windings 218 and 216 have different number turns and different dimensions.

[0050] FIG. 14 illustrates a layout 1400 of the winding 218. In the illustrated embodiment, the winding 218 comprises the phase A winding 1302, the phase B winding 1304 and the phase C winding 1306 that are star connected with one parallel path to each winding.

[0051] FIG. 15 illustrates a plot 1500 of a magnetomotive force (MMF) generated by the winding 218 in the air gap 222 (see FIG. 2). The plot 1500 includes a phase A MMF 1502, a phase B MMF 1504, a phase C MMF 1506, and a total MMF 1508 as a function of a location within the air gap 222 defined by the mechanical angle 224 (see FIG. 2).

[0052] FIG. 16 illustrates a harmonic analysis of the MMF generated by the winding 218 in the air gap 222 (see FIG. 2). In particular, FIG. 16 illustrates a spectrum 1600 of the total MMF 1508 (see FIG. 15) determined by the FFT. The spectrum 1600 comprises a plurality of harmonics 1602. In the illustrated embodiment, high-order harmonics have less weights compared to the 1st order harmonic 1602-1, with the forty-seventh order harmonic 1602-2 having a largest weight among the high-order harmonics. In certain embodiments, weights of the high-order harmonics may be reduced with the help of the B2B converter 106 (see FIG. 1).

[0053] FIG. 17 illustrates a slot star plot 1700 of the winding 218. The slot star plot 1700 illustrates the MMF distribution generated by the winding 218. The slot star plot 1700 shows that the MMF is sinusoidally distributed in the airgap 222 (see FIG. 2) such that a balanced electromagnetic signal can be produced.Back-to-back Converter

[0054] The B2B converter 106 (see FIG. 1) comprises a first voltage source converter 120 electrically coupled to a second voltage source converter 122 via a capacitor 124. Each of the first voltage source converter 120 and the second voltage source converter 122 is configured to function both as a converter, to convert electric power from alternating current (AC) to direct current (DC), and as an inverter, to convert electric power from DC to AC. Each of the first voltage source converter 120 and the second voltage source converter 122 may comprise a plurality of transistors and a plurality of capacitors. In certain embodiments, a voltage source converter includes a multilevel converter arrangement. The multilevel converter arrangement includes converter bridges or cells connected in series, each converter cell including a pair of series connected transistors connected in parallel with a capacitor. The transistors may be silicon carbide-based metal-oxide semiconductor field-effect transistors, insulated-gate bipolar transistors and / or gallium nitride transistors.

[0055] An AC terminal 126 of the first voltage source converter 120 is electrically coupled to the winding 220 (see FIG. 2) of the stator 210 using the wiring 110 and a DC terminal 128 ofthe first voltage source converter 120 is electrically coupled to the capacitor 124. An AC terminal 132 of the second voltage source converter 122 is electrically coupled to the winding 218 (see FIG. 2) of the stator 210 using the wiring 112 and a DC terminal 130 of the second voltage source converter 122 is electrically coupled to the capacitor 124.

[0056] In operation, the first voltage source converter 120 is configured to provide one or more control signals 148 to the winding 220 of the stator 210 via the wiring 1 10 and the second voltage source converter 122 is configured to provide one or more control signals 150 to the winding 218 of the stator 210 via the wiring 112.Control system

[0057] The control system 136 is generally any device that is configured to process data and communicate with other components of the flux-modulated electromagnetic apparatus 100 via the network 134. The control system 136 may comprise a processor 138 in signal communication with a memory 142 and a network interface 140.

[0058] Processor 138 comprises one or more processors operably coupled to the memory 142. Processor 138 is any electronic circuitry, including, but not limited to, state machines, one or more central processing unit (CPU) chips, logic units, cores (e.g., a multi-core processor), field- programmable gate array (FPGAs), application-specific integrated circuits (ASICs), or digital signal processors (DSPs). Processor 138 may be a programmable logic device, a microcontroller, a microprocessor, or any suitable combination of the preceding. The one or more processors are configured to process data and may be implemented in hardware or software. For example, processor 138 may be 8-bit, 16-bit, 32-bit, 64-bit, or of any other suitable architecture. The one or more processors are configured to implement various software instructions to perform operations of the control system 136.

[0059] Network interface 140 is configured to enable wired and / or wireless communications (e.g., via network 134). Network interface 140 is configured to communicate data between the control system 136 and other components of the flux-modulated electromagnetic apparatus 100 (e.g., B2B converter 106). For example, network interface 140 may comprise a WIFI interface, a local area network (LAN) interface, a wide area network (WAN) interface, a modem, a switch, or a router. Processor 138 is configured to send and receive data using network interface140. Network interface 140 may be configured to use any suitable type of communication protocol as would be appreciated by one of ordinary skill in the art.

[0060] Memory 142 comprises a non-transitory computer-readable medium such as one or more disks, tape drives, or solid-state drives, and may be used as an over-flow data storage device, to store programs when such programs are selected for execution, and to store instructions and data that are read during program execution. Memory 142 may be volatile or non-volatile and may comprise a read-only memory (ROM), random-access memory (RAM), ternary content-addressable memory (TCAM), dynamic random-access memory (DRAM), and static random-access memory (SRAM). Memory 142 may be implemented using one or more disks, tape drives, solid-state drives, and / or the like. Memory 142 may store any of the information described in FIGS. 1 and 2 along with any other data, instructions, logic, rules, or code operable to implement the function(s) described herein. Memory 142 is operable to store software instructions 144 and / or any other data and instructions. Software instructions 144 may comprise any suitable set of software instructions, logic, rules, or code operable to be executed by processor 138.

[0061] In operation, the processor 138 of control system 136 is configured to generate one or more instructions 146 and send the one or more instructions 146 to the B2B converter 106 via the network 134. In the illustrated embodiment, the processor 138 sends the one or more instructions 146 to the first voltage source converter 120 of the B2B converter 106. In other embodiments, the processor 138 may send the one or more instructions 146 to the second voltage source converter 122 of the B2B converter 106. In yet other embodiments, the processor 138 may send the one or more instructions 146 to both the first voltage source converter 120 and the second voltage source converter 122 of the B2B converter 106.

[0062] In certain embodiments, the one or more instructions 146 may be determined based on a current angular speed a)rand a synchronous angular speed a)rsof the rotor 202. The one or more instructions 146 may instruct the B2B converter 106 to generate one or more control signals 148 for the winding 220 ofthe stator 210 and / or one or more control signals 150 for the winding 218 of the stator 210, such that the one or more control signals 148 and / or 160 alter the synchronous angular speed a)rsand cause the synchronous angular speed a)rsto match the current angular speed a)r. The one or more instructions 146 may be determined and sent to theB2B converter 106 for a desired time period, such that the synchronous angular speed &>rsmatches the current angular speed a)rfor the desired time period.

[0063] While several embodiments have been provided in the present disclosure, it should be understood that the disclosed systems and methods might be embodied in many other specific forms without departing from the spirit or scope of the present disclosure. The present examples are to be considered as illustrative and not restrictive, and the intention is not to be limited to the details given herein. For example, the various elements or components may be combined or integrated with another system or certain features may be omitted, or not implemented.

[0064] In addition, techniques, systems, subsystems, and methods described and illustrated in the various embodiments as discrete or separate may be combined or integrated with other systems, modules, techniques, or methods without departing from the scope of the present disclosure. Other items shown or discussed as coupled or directly coupled or communicating with each other may be indirectly coupled or communicating through some interface, device, or intermediate component whether electrically, mechanically, or otherwise. Other examples of changes, substitutions, and alterations are ascertainable by one skilled in the art and could be made without departing from the spirit and scope disclosed herein.

[0065] To aid the Patent Office, and any readers of any patent issued on this application in interpreting the claims appended hereto, applicants note that they do not intend any of the appended claims to invoke 35 U.S.C. § 112(f) as it exists on the date of filing hereof unless the words “means for” or “step for” are explicitly used in the particular claim.

Claims

CLAIMS1. A flux-modulated electromagnetic apparatus comprising: an induction machine comprising: a rotor comprising: a core; and a rotor winding comprising a plurality of metal bars in contact with an outer surface of the rotor or an outer surface of the core; a stator surrounding the rotor, the stator comprising: a plurality of slots at an inner surface of the stator; a power winding extending through a first set of the plurality of slots, wherein the power winding is configured to electrically couple to a power grid; a first control winding extending through a second set of the plurality of slots; and a second control winding extending through a third set of the plurality of slots; and an air gap between the inner surface of the stator and the outer surface of the rotor; a first voltage source converter electrically coupled to the stator and having a first alternating current (AC) terminal and a first direct current (DC) terminal; and a second voltage source converter electrically coupled to the stator and having a second AC terminal and a second DC terminal, wherein: the first DC terminal is electrically coupled to the second DC terminal via a capacitor; the first AC terminal is electrically coupled to the first control winding; and the second AC terminal is electrically coupled to the second control winding.

2. The flux-modulated electromagnetic apparatus of Claim 1, further comprising: a gearbox mechanically coupled to the rotor; and a plurality of blades mechanically coupled to the gearbox.

3. The flux-modulated electromagnetic apparatus of Claim 1, wherein each of the power winding, the first control winding and the second control winding is a three-phase winding.

4. The flux-modulated electromagnetic apparatus of Claim 1, wherein a pole pair number of the power winding is 2.

5. The flux-modulated electromagnetic apparatus of Claim 1, wherein a pole pair number of the first control winding is 4.

6. The flux-modulated electromagnetic apparatus of Claim 1, wherein a pole pair number of the second control winding is 2.

7. The flux-modulated electromagnetic apparatus of Claim 1 , wherein the plurality of slots comprises 48 slots.

8. The flux-modulated electromagnetic apparatus of Claim 1 , wherein the plurality of metal bars comprises 30 metal bars.

9. The flux-modulated electromagnetic apparatus of Claim 1, wherein the power winding and the second control winding comprise a different number of turns.

10. The flux-modulated electromagnetic apparatus of Claim 1, wherein the core comprises cylindrical laminated steel.

11. The flux-modulated electromagnetic apparatus of Claim 1, wherein the control winding, the first winding, and the second winding are each wrapped around the rotor.

12. The flux-modulated electromagnetic apparatus of Claim 1, wherein the rotor winding comprises a plurality of metal bars embedded at an outer surface of the core.

13. The flux-modulated electromagnetic apparatus of Claim 1, wherein the rotor winding is wound around an outer surface of the rotor.

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