Wound rotor electric machine

Abstract

A system for converting energy includes a doubly-fed induction machine including a rotor having a plurality of rotor windings and a stator having a plurality of stator windings. The system also includes a power conversion unit in electrical communication with the plurality of rotor windings, wherein the power conversion unit is configured to excite the plurality of rotor windings with alternating current. The system also includes a relay unit in electrical communication with the plurality of stator windings, wherein the relay unit is configured to electrically interconnect a plurality of terminals of the plurality of stator windings. The system also includes a controller in electrical communication with the power conversion unit and the relay unit, wherein the controller is programmed to regulate operation of the doubly-fed induction machine using the power conversion unit and the relay unit based on a rotational speed of the rotor.

Description

Technical Field

[0001] This disclosure relates to a system for converting energy, and more specifically, to a narrowband independent speed variable frequency motor. Background Technology

[0002] Electric motors (e.g., generators and motors) have been developed to convert mechanical energy into electrical energy or vice versa. Typically, the output power characteristics of an electric motor are related to the characteristics of its mechanical inputs. For example, in some motors, the frequency of the output power can be proportional to the motor's rotational speed. Generally, regardless of the characteristics of the mechanical inputs, specific characteristics of the output power are desired. For example, in some applications, it may be desirable to provide output power with a specific amplitude over a frequency range. However, the systems developed to regulate the output power characteristics of electric motors are often large, bulky, and prone to mechanical wear.

[0003] Therefore, while current systems for energy conversion have achieved their intended purpose, a new and improved system for energy conversion is needed. Summary of the Invention

[0004] According to several aspects, a system for energy conversion is provided. The system includes a doubly-fed induction motor, which includes a rotor having multiple rotor windings and a stator having multiple stator windings. The system also includes a power conversion unit electrically connected to the multiple rotor windings, wherein the power conversion unit is configured to excite the multiple rotor windings with alternating current. The system further includes a relay unit electrically connected to the multiple stator windings, wherein the relay unit is configured to electrically interconnect multiple terminals of the multiple stator windings. The system also includes a controller electrically connected to the power conversion unit and the relay unit, wherein the controller is programmed to determine the rotor's rotational speed and, based on the rotor's rotational speed, regulate the operation of the doubly-fed induction motor using the power conversion unit and the relay unit.

[0005] In another aspect of this disclosure, the plurality of rotor windings further includes a first three-phase rotor winding having a first rotor winding coil, a second rotor winding coil, and a third rotor winding coil. The plurality of rotor windings also includes a second three-phase rotor winding having a fourth rotor winding coil, a fifth rotor winding coil, and a sixth rotor winding coil. The plurality of stator windings further includes a first three-phase stator winding having: a first stator winding coil having a first terminal and a second terminal; a second stator winding coil having a first terminal and a second terminal; and a third stator winding coil having a first terminal and a second terminal. The plurality of stator windings also includes a second three-phase stator winding having: a fourth stator winding coil having a first terminal and a second terminal; a fifth stator winding coil having a first terminal and a second terminal; and a sixth stator winding coil having a first terminal and a second terminal. The system also includes a first output terminal, a second output terminal, and a third output terminal.

[0006] In another aspect of this disclosure, the power conversion unit may further include a first inverter having three outputs, wherein each output of the first inverter is electrically connected to one of a first rotor winding coil, a second rotor winding coil, or a third rotor winding coil. The power conversion unit may also include a second inverter having three outputs, wherein each output of the second inverter is electrically connected to one of a fourth rotor winding coil, a fifth rotor winding coil, or a sixth rotor winding coil. The first and second inverters are configured to be powered by a direct current (DC) power supply.

[0007] In another aspect of this disclosure, the system also includes a slip ring configured to provide electrical communication between each output of the first inverter and one of a first rotor winding coil, a second rotor winding coil, or a third rotor winding coil, and between each output of the second inverter and one of a fourth rotor winding coil, a fifth rotor winding coil, or a sixth rotor winding coil.

[0008] In another aspect of this disclosure, the relay unit may further include a plurality of solid-state relays electrically connected to the first three-phase stator winding and the second three-phase stator winding.

[0009] In another aspect of this disclosure, in order to regulate the operation of the doubly-fed induction motor, the controller is also programmed to, when the doubly-fed induction motor is used as a generator, adjust the excitation frequency of the first three-phase rotor winding using the first inverter of the power conversion unit and adjust the excitation frequency of the second three-phase rotor winding using the second inverter of the power conversion unit, based on the rotor's rotational speed, so as to regulate the output voltage frequency.

[0010] In another aspect of this disclosure, for regulating the operation of the doubly-fed induction motor, the controller is also programmed to configure the doubly-fed induction motor with four effective poles based on the rotor's rotational speed, using a power conversion unit and a relay unit, when the doubly-fed induction motor is used as a generator, to regulate the output voltage frequency. For regulating the operation of the doubly-fed induction motor, the controller is also programmed to configure the doubly-fed induction motor with eight effective poles based on the rotor's rotational speed, using a power conversion unit and a relay unit.

[0011] In another aspect of this disclosure, in order to configure the doubly-fed induction motor to have four effective poles, the controller is further programmed to configure the first inverter to excite the first rotor winding coil with a first sinusoidal current, to excite the second rotor winding coil with a second sinusoidal current, wherein the second sinusoidal current lags the first sinusoidal current by 240 degrees, and to excite the third rotor winding coil with a third sinusoidal current, wherein the third sinusoidal current lags the first sinusoidal current by 120 degrees. In order to configure the doubly-fed induction motor to have four effective poles, the controller is further programmed to: configure the second inverter to excite the fourth rotor winding coil with a fourth sinusoidal current, wherein the fourth sinusoidal current is 180 degrees out of phase with the first sinusoidal current; to excite the fifth rotor winding coil with a fifth sinusoidal current, wherein the fifth sinusoidal current is 180 degrees out of phase with the second sinusoidal current; and to excite the sixth rotor winding coil with a sixth sinusoidal current, wherein the sixth sinusoidal current is 180 degrees out of phase with the third sinusoidal current. To configure the doubly-fed induction motor with four active poles, the controller is also programmed to configure the relay unit to electrically connect the first terminal of the first stator winding coil to the second output terminal and the first terminal of the sixth stator winding coil. To configure the doubly-fed induction motor with four active poles, the controller is also programmed to configure the relay unit to electrically connect the first terminal of the second stator winding coil to the third output terminal and the first terminal of the fifth stator winding coil. To configure the doubly-fed induction motor with four active poles, the controller is also programmed to configure the relay unit to electrically connect the first terminal of the third stator winding coil to the first output terminal and the first terminal of the fourth stator winding coil. To configure the doubly-fed induction motor with four active poles, the controller is also programmed to configure the relay unit to electrically connect the second terminal of the fourth stator winding coil to the second terminals of the fifth stator winding coil and the second terminals of the sixth stator winding coil.

[0012] In another aspect of this disclosure, to configure the doubly-fed induction motor to have eight effective poles, the controller is further programmed to configure the first inverter to excite the first rotor winding coil with a first sinusoidal current; to excite the second rotor winding coil with a second sinusoidal current, wherein the second sinusoidal current lags the first sinusoidal current by 120 degrees; and to excite the third rotor winding coil with a third sinusoidal current, wherein the third sinusoidal current lags the second sinusoidal current by 120 degrees. To configure the doubly-fed induction motor to have eight effective poles, the controller is further programmed to configure the second inverter to excite the fourth rotor winding coil with the first sinusoidal current, the fifth rotor winding coil with the second sinusoidal current, and the sixth rotor winding coil with the third sinusoidal current. To configure the doubly-fed induction motor to have eight effective poles, the controller is further programmed to configure the relay unit to electrically connect the first terminal of the first stator winding coil to the third output terminal and the second terminal of the sixth stator winding coil. To configure the doubly-fed induction motor with eight active poles, the controller is also programmed to configure the relay unit to electrically connect the first terminal of the second stator winding coil to the second output terminal and the second terminal of the fifth stator winding coil. To configure the doubly-fed induction motor with eight active poles, the controller is also programmed to configure the relay unit to electrically connect the first terminal of the third stator winding coil to the first output terminal and the second terminal of the fourth stator winding coil. To configure the doubly-fed induction motor with eight active poles, the controller is also programmed to configure the relay unit to electrically connect the first terminal of the fourth stator winding coil to the first terminal of the fifth stator winding coil and the first terminal of the sixth stator winding coil.

[0013] According to several aspects, a system for converting energy is provided. The system includes a doubly-fed induction motor, which includes a rotor having multiple rotor windings and a stator having multiple stator windings. The system also includes a power conversion unit wirelessly communicated with the multiple rotor windings, wherein the power conversion unit is configured to excite the multiple rotor windings with alternating current. The system further includes a relay unit electrically communicated with the multiple stator windings, wherein the relay unit is configured to electrically interconnect multiple terminals of the multiple stator windings. The system also includes a controller electrically communicated with the power conversion unit and the relay unit, wherein the controller is programmed to determine the rotor's rotational speed and, based on the rotor's rotational speed, regulate the operation of the doubly-fed induction motor using the power conversion unit and the relay unit.

[0014] In another aspect of this disclosure, the plurality of rotor windings further includes a first three-phase rotor winding having a first rotor winding coil, a second rotor winding coil, and a third rotor winding coil. The plurality of rotor windings also includes a second three-phase rotor winding having a fourth rotor winding coil, a fifth rotor winding coil, and a sixth rotor winding coil. The plurality of stator windings further includes a first three-phase stator winding having: a first stator winding coil having a first terminal and a second terminal; a second stator winding coil having a first terminal and a second terminal; and a third stator winding coil having a first terminal and a second terminal. The plurality of stator windings also includes a second three-phase stator winding having: a fourth stator winding coil having a first terminal and a second terminal; a fifth stator winding coil having a first terminal and a second terminal; and a sixth stator winding coil having a first terminal and a second terminal. The system also includes a first output terminal, a second output terminal, and a third output terminal.

[0015] In another aspect of this disclosure, the power conversion unit may further include a first inverter with three outputs: each output of the first inverter is electrically connected to one of a first rotor winding coil, a second rotor winding coil, or a third rotor winding coil. The power conversion unit may also include a second inverter with three outputs: each output of the second inverter is electrically connected to one of a fourth rotor winding coil, a fifth rotor winding coil, or a sixth rotor winding coil. The first and second inverters are fixed to the rotor.

[0016] In another aspect of this disclosure, the power conversion unit may further include a wireless power transmission system, which includes a fixed power transmission inverter and a fixed wireless power transmission coil electrically connected to the fixed power transmission inverter. The wireless power transmission system also includes a rotating power transmission rectifier fixed to the rotor and a rotating wireless power transmission coil fixed to the rotor, wherein the rotating wireless power transmission coil is electrically connected to the rotating power transmission rectifier and a first inverter and a second inverter of the power conversion unit. The fixed wireless power transmission coil is inductively coupled to the rotating wireless power transmission coil to transmit power between the fixed power transmission inverter and the rotating power transmission rectifier. The power conversion unit may also include a wireless data transmission system, which includes a fixed wireless data transceiver and a rotating wireless data transceiver fixed to the rotor. The wireless data transmission system also includes a rotating controller fixed to the rotor, wherein the rotating controller is electrically connected to the rotating wireless data transceiver and the first inverter and the second inverter of the power conversion unit. The rotary controller is programmed to receive command data from a fixed wireless transceiver using a rotary wireless transceiver, and to regulate the operation of the first and second inverters of the power conversion unit based at least in part on the command data.

[0017] In another aspect of this disclosure, the relay unit may further include a plurality of solid-state relays electrically connected to the first three-phase stator winding and the second three-phase stator winding.

[0018] In another aspect of this disclosure, in order to regulate the operation of the doubly-fed induction motor, the controller is also programmed to, when the doubly-fed induction motor is used as a generator, use a first inverter of the power conversion unit to adjust the excitation frequency of the first three-phase rotor winding based on the rotor's rotational speed, and use a second inverter of the power conversion unit to adjust the excitation frequency of the second three-phase rotor winding, so as to regulate the output voltage frequency.

[0019] In another aspect of this disclosure, for regulating the operation of the doubly-fed induction motor, the controller is also programmed to configure the doubly-fed induction motor with four effective poles based on the rotor's rotational speed, using a power conversion unit and a relay unit, when the doubly-fed induction motor is used as a generator, to regulate the output voltage frequency. For regulating the operation of the doubly-fed induction motor, the controller is also programmed to configure the doubly-fed induction motor with eight effective poles based on the rotor's rotational speed, using a power conversion unit and a relay unit.

[0020] In another aspect of this disclosure, in order to configure the doubly-fed induction motor to have four effective poles, the controller is further programmed to configure the first inverter to excite the first rotor winding coil with a first sinusoidal current; to excite the second rotor winding coil with a second sinusoidal current, wherein the second sinusoidal current lags the first sinusoidal current by 240 degrees; and to excite the third rotor winding coil with a third sinusoidal current, wherein the third sinusoidal current lags the first sinusoidal current by 120 degrees. In order to configure the doubly-fed induction motor to have four effective poles, the controller is further programmed to configure the second inverter to excite the fourth rotor winding coil with a fourth sinusoidal current, wherein the fourth sinusoidal current is 180 degrees out of phase with the first sinusoidal current; to excite the fifth rotor winding coil with a fifth sinusoidal current, wherein the fifth sinusoidal current is 180 degrees out of phase with the second sinusoidal current; and to excite the sixth rotor winding coil with a sixth sinusoidal current, wherein the sixth sinusoidal current is 180 degrees out of phase with the third sinusoidal current. To configure the doubly-fed induction motor with four active poles, the controller is also programmed to configure the relay unit to electrically connect the first terminal of the first stator winding coil to the second output terminal and the first terminal of the sixth stator winding coil. To configure the doubly-fed induction motor with four active poles, the controller is also programmed to configure the relay unit to electrically connect the first terminal of the second stator winding coil to the third output terminal and the first terminal of the fifth stator winding coil. To configure the doubly-fed induction motor with four active poles, the controller is also programmed to configure the relay unit to electrically connect the first terminal of the third stator winding coil to the first output terminal and the first terminal of the fourth stator winding coil. To configure the doubly-fed induction motor with four active poles, the controller is also programmed to configure the relay unit to electrically connect the second terminal of the fourth stator winding coil to the second terminal of the fifth stator winding coil and the second terminal of the sixth stator winding coil.

[0021] In another aspect of this disclosure, in order to configure the doubly-fed induction motor to have eight effective poles, the controller is further programmed to configure the first inverter to excite the first rotor winding coil with a first sinusoidal current; to excite the second rotor winding coil with a second sinusoidal current, wherein the second sinusoidal current lags the first sinusoidal current by 120 degrees; and to excite the third rotor winding coil with a third sinusoidal current, wherein the third sinusoidal current lags the second sinusoidal current by 120 degrees. In order to configure the doubly-fed induction motor to have eight effective poles, the controller is further programmed to configure the second inverter to excite the fourth rotor winding coil with the first sinusoidal current; to excite the fifth rotor winding coil with the second sinusoidal current; and to excite the sixth rotor winding coil with the third sinusoidal current. In order to configure the doubly-fed induction motor to have eight effective poles, the controller is further programmed to configure the relay unit to electrically connect the first terminal of the first stator winding coil to the third output terminal and the second terminal of the sixth stator winding coil. To configure the doubly-fed induction motor with eight active poles, the controller is also programmed to configure the relay unit to electrically connect the first terminal of the second stator winding coil to the second output terminal and the second terminal of the fifth stator winding coil. To configure the doubly-fed induction motor with eight active poles, the controller is also programmed to configure the relay unit to electrically connect the first terminal of the third stator winding coil to the first output terminal and the second terminal of the fourth stator winding coil. To configure the doubly-fed induction motor with eight active poles, the controller is also programmed to configure the relay unit to electrically connect the first terminal of the fourth stator winding coil to the first terminal of the fifth stator winding coil and the first terminal of the sixth stator winding coil.

[0022] An electric motor is provided according to several aspects. The motor includes a stator having a hollow cylindrical shape, the stator including a plurality of stator slots arranged at uniform intervals along the circumference of the stator. The stator also includes a first stator coil, a second stator coil, a third stator coil, a fourth stator coil, a fifth stator coil, and a sixth stator coil, wherein each stator coil has a first stator coil loop electrically connected in series with a second stator coil loop. For each of the first, second, third, fourth, fifth, and sixth stator coils, the first stator coil loop is disposed in a first pair of stator slots, wherein a second pair of stator slots is disposed between the first pair of stator slots. The second stator coil loop is disposed in a third pair of stator slots, wherein a fourth pair of stator slots is disposed between the third pair of stator slots, and wherein the second stator coil loop and the first stator coil loop are diametrically opposed. The motor also includes a rotor rotatably disposed within the stator along the central axis of the stator, the rotor including a plurality of rotor slots arranged at uniform intervals along the circumference of the rotor. The rotor also includes a first rotor coil, a second rotor coil, a third rotor coil, a fourth rotor coil, a fifth rotor coil, and a sixth rotor coil. Each rotor coil has a first rotor coil loop that is electrically connected in series with the second rotor coil loop. For each of the first, second, third, fourth, fifth, and sixth rotor coils, the first rotor coil loop is disposed in a first pair of rotor slots, wherein a second pair of rotor slots is disposed between the first pair of rotor slots. The second rotor coil loop is disposed in a third pair of rotor slots, wherein a fourth pair of rotor slots is disposed between the third pair of rotor slots, and wherein the second rotor coil loop is diametrically opposed to the first rotor coil loop.

[0023] In another aspect of this disclosure, the motor also includes a controller fixed to the outer surface of the stator, wherein the controller is programmed to determine the rotational speed of the rotor and, at least in part based on the rotational speed of the rotor, electrically change the number of poles of the rotor and stator by adjusting the phase angle of each phase of a three-phase current source electrically connected to the rotor coils and changing a plurality of electrical connections between each of these stator coils.

[0024] Other areas of application will become apparent from the description provided herein. It should be understood that the specification and specific embodiments are for illustrative purposes only and are not intended to limit the scope of this disclosure. Attached Figure Description

[0025] The accompanying drawings described herein are for illustrative purposes only and are not intended to limit the scope of this disclosure in any way.

[0026] Figure 1 This is a block diagram of a system for energy conversion according to an exemplary embodiment;

[0027] Figure 2AThis is a diagram illustrating the stator winding configuration of an electric motor according to an exemplary embodiment;

[0028] Figure 2B This is a diagram showing the winding profile of the rotor of an electric motor according to an exemplary embodiment;

[0029] Figure 3 This is a schematic diagram of a relay unit connected to the stator winding of a motor according to an exemplary embodiment;

[0030] Figure 4 This is a block diagram of an alternative system for energy conversion according to an exemplary embodiment; and

[0031] Figure 5 This is an illustration of an operating mode of a system for converting energy according to an exemplary embodiment. Detailed Implementation

[0032] The following description is merely exemplary in nature and is not intended to limit this disclosure, application, or use.

[0033] refer to Figure 1 The figure illustrates a block diagram of a system for energy conversion, and is generally indicated by reference numeral 10. System 10 typically includes a doubly fed induction motor 12, a power conversion unit 14, multiple slip rings 15, a relay unit 16, and a controller 18.

[0034] A doubly-fed induction motor 12 is used to convert mechanical energy into electrical energy and / or electrical energy into mechanical energy. The doubly-fed induction motor 12 includes a stator 20 and a rotor 22. The stator 20 has a hollow cylindrical shape, and the rotor 22 has a solid cylindrical shape. The rotor 22 is rotatably suspended along the central axis of the stator 20. The structure of the stator 20 and rotor 22 will be discussed in further detail with reference to FIG2. In a non-limiting example, when the doubly-fed induction motor 12 is used to convert mechanical energy into electrical energy (i.e., as a generator), the rotor 22 is fixed to a source of rotating mechanical energy, such as an internal combustion engine, a jet engine, or a wind turbine. In another non-limiting example, when the doubly-fed induction motor 12 is used to convert electrical energy into mechanical energy, the stator 20 is electrically connected to an electrical energy source to rotate the rotor 22, which is then fixed to a mechanical load, and the rotor 22 rotates to provide energy to the mechanical load. In this disclosure, the term "doubly-fed" means that both the stator 20 and the rotor 22 of the doubly-fed induction motor 12 can be supplied with electrical energy.

[0035] The stator 20 is a fixed component of a doubly-fed induction motor 12 that converts electrical energy into magnetic field energy and / or magnetic field energy into electrical energy. The stator 20 includes a first three-phase stator winding 24 and a second three-phase stator winding 26. The first three-phase stator winding 24 has a first stator winding coil 28, a second stator winding coil 30, and a third stator winding coil 32. The second three-phase stator winding 26 has a fourth stator winding coil 34, a fifth stator winding coil 36, and a sixth stator winding coil 38. The first three-phase stator winding 24 and the second three-phase stator winding 26 are electrically connected to a relay unit 16. Referring to Figure 2 and... Figure 3 The electrical connections of stator 20 are discussed in more detail. In a non-limiting example, when a changing magnetic field exists in the three-phase stator windings 24 and 26, a current is induced in the three-phase stator windings 24 and 26, thereby converting the energy of the changing magnetic field into electrical energy. In another non-limiting example, when the three-phase stator windings 24 and 26 are excited by a changing electric field, a changing magnetic field is induced near the three-phase stator windings 24 and 26, thereby converting the energy of the changing electric field into a changing magnetic field.

[0036] The rotor 22 is a rotating component of a doubly-fed induction motor 12 that converts electrical energy into magnetic field energy and / or magnetic field energy into electrical energy. The rotor 22 includes a first three-phase rotor winding 40 and a second three-phase rotor winding 42. The first three-phase rotor winding 40 has a first rotor winding coil 44, a second rotor winding coil 46, and a third rotor winding coil 48. The second three-phase rotor winding 42 has a fourth rotor winding coil 50, a fifth rotor winding coil 52, and a sixth rotor winding coil 54. The first three-phase rotor winding 40 has first winding terminals 56, second winding terminals 58, and third winding terminals 60 for connecting the first three-phase rotor winding 40 to the power conversion unit 14 using multiple slip rings 15. The second three-phase rotor winding 42 has fourth winding terminals 62, fifth winding terminals 64, and sixth winding terminals 66 for connecting the second three-phase rotor winding 42 to the power conversion unit 14 using multiple slip rings 15.

[0037] exist Figure 1In the exemplary embodiment shown, the first rotor winding coil 44, the second rotor winding coil 46, and the third rotor winding coil 48 are connected in a delta configuration. In this delta configuration, a first terminal of the first rotor winding coil 44 is connected to a first terminal of the second rotor winding coil 46, a second terminal of the second rotor winding coil 46 is connected to a first terminal of the third rotor winding coil 48, and a second terminal of the third rotor winding coil 48 is connected to a second terminal of the first rotor winding coil 44. A first winding terminal 56 is connected to the first terminals of the first rotor winding coil 44 and the second rotor winding coil 46. A second winding terminal 58 is connected to the second terminals of the second rotor winding coil 46 and the first terminal of the third rotor winding coil 48. A third winding terminal 60 is connected to the second terminal of the third rotor winding coil and the second terminal of the first rotor winding coil 44. The fourth winding coil 50, the fifth winding coil 52, and the sixth rotor winding coil 54 are connected to the fourth winding terminal 62, the fifth winding terminal 64, and the sixth winding terminal 66 in the same manner as the first rotor winding coil 44, the second rotor winding coil 46, and the third rotor winding coil 48 described above. In other exemplary embodiments, the rotor winding coils 44, 46, 48, 50, 52, and 54 are connected in two Y-shaped configurations.

[0038] In a non-limiting example, when a changing magnetic field exists in the three-phase rotor windings 40 and 42, a current is induced in the three-phase rotor windings 40 and 42, thereby converting the energy of the changing magnetic field into electrical energy. In another non-limiting example, when the three-phase rotor windings 40 and 42 are excited by a changing electric field, a changing magnetic field is induced near the three-phase rotor windings 40 and 42, thereby converting the energy of the changing electric field into a changing magnetic field.

[0039] Power conversion unit 14 is used to convert direct current (DC) power supplies 72a and 72b into two three-phase alternating current (AC) power supplies, and to supply the three-phase AC power supplies to each of the three-phase rotor windings 40 and 42. Figure 1In the exemplary embodiment shown, the power conversion unit 14 includes a first inverter 68 and a second inverter 70. Inverters 68 and 70 convert direct current (DC) to alternating current (AC) and allow controller 18 to control various characteristics of the AC power. In a non-limiting example, inverters 68 and 70 respond to data signals from controller 18 by adjusting the amplitude, frequency, and / or phase angle of the AC current and / or voltage output. Inverters 68 and 70 are connected to DC power supplies 72a and 72b and provide AC power to each of the rotor winding terminals 56, 58, 60, 62, 64, and 66 using a plurality of slip rings 15. Inverters 68 and 70 are also electrically connected to controller 18. It should be understood that other methods of communication between inverters 68 and 70 and controller 18 (including wireless, wired, electrical, optical, and / or optoelectronic communication) are within the scope of this disclosure. In exemplary embodiments, inverters 68 and 70 are square wave, modified sine wave, pulsed sine wave, pulse width modulation (PWM) wave, or pure sine wave inverters. It should be understood that other types of inverters or other electrical devices designed to convert direct current (DC) to alternating current (AC) fall within the scope of this disclosure.

[0040] Multiple slip rings 15 are used to transmit alternating current (AC) between the power conversion unit 14 and the rotor 22 of the doubly-fed induction motor 12. The slip rings 15 are electromechanical devices that allow power to be transferred from a stationary structure to a rotating structure. In an exemplary embodiment, the slip rings include six conductive rings fixed to the rotor 22 and six conductive contacts fixed to the power conversion unit 14. The conductive contacts contact the conductive rings to form six consecutive conductive paths between the power conversion unit 14 and the rotor winding terminals 56, 58, 60, 62, 64, 66.

[0041] Relay unit 16 is used to switch the electrical connection between stator winding coils 28, 30, 32, 34, 36, 38 and the outputs 74, 76, and 78 of the first relay unit, the second relay unit, and the third relay unit. (See reference...) Figure 3 An exemplary embodiment of the relay unit 16 and its connections to the stator winding coils 28, 30, 32, 34, 36, and 38 are discussed in more detail below. The relay unit 16 is electrically connected to the stator winding coils 28, 30, 32, 34, 36, and 38, the controller 18, and the relay unit outputs 74, 76, and 78.

[0042] The controller 18 is used to control the operation of the doubly-fed induction motor 12 using the power conversion unit 14 and the relay unit 16. The controller 18 includes at least one processor 80 and a non-transitory computer-readable storage device or medium 82. The processor 80 may be a custom or commercially available processor, a central processing unit (CPU), a graphics processing unit (GPU), an auxiliary processor among several processors associated with the controller 18, a semiconductor-based microprocessor (in the form of a microchip or chipset), a macroprocessor, a combination thereof, or a device generally used for executing instructions. The computer-readable storage device or medium 82 may include, for example, volatile and non-volatile storage in read-only memory (ROM), random access memory (RAM), and keep-alive memory (KAM). Keep-alive memory (KAM) is a permanent or non-volatile memory that can be used to store various operational variables when the processor 80 is powered off. The computer-readable storage device or medium 82 may be implemented using multiple storage devices, such as programmable read-only memory (PROM), electrical PROM (EPROM), electrically erasable PROM (EEPROM), flash memory, or another electrical, magnetic, optical, or combined storage device capable of storing data, some of which may be used by controller 18 to control executable instructions of system 10. Controller 18 may also include multiple controllers electrically connected to each other.

[0043] The controller 18 is electrically connected to the power conversion unit 14 and the relay unit 16. The medium 82 of the controller 18 contains executable instructions for controlling the operation of the doubly-fed induction motor 12 using the power conversion unit 14 and the relay unit 16.

[0044] See Figure 2A The diagram illustrates the winding profile of the stator 20 according to an exemplary embodiment and is generally indicated by reference numeral 90. Figure 2A In the exemplary embodiment shown, the stator 20 is a hollow cylinder having a plurality of stator slots 92 arranged at uniform intervals along the circumference of the stator 20. Figure 2AIn an exemplary embodiment, the stator 20 has 24 stator slots 92. It should be understood that alternative embodiments including different numbers of stator slots 92 are included within the scope of this disclosure. The stator winding profile 90 includes six stator winding coils 28, 30, 32, 34, 36, 38, each stator winding coil having a first stator coil loop 94 and a second stator coil loop 96 connected in series. It should be understood that alternative embodiments including more than two stator coil loops and / or stator coil loops connected in series and / or in parallel are included within the scope of this disclosure. The first stator coil loop 94 and the second stator coil loop 96 include multiple conductor loops disposed in a pair of stator slots 92. For example, the first stator coil loop 94 is disposed in a first stator slot 98 and a second stator slot 100. The first stator slot 98 is separated from the second stator slot 100 by a third stator slot 102 and a fourth stator slot 104. The second stator coil loop 96 is disposed in a fifth stator slot 106 and a sixth stator slot 108. The fifth stator slot 106 is separated from the sixth stator slot 108 by the seventh stator slot 110 and the eighth stator slot 112. Therefore, the first stator coil ring 94 is diametrically opposite the second stator coil ring 96. Figure 2A As shown, the above-described line pattern is repeated for each stator coil loop of the six stator winding coils 28, 30, 32, 34, 36, and 38. The stator 20 has a central axis 114 located at the center of the hollow portion of the stator 20.

[0045] See Figure 2B The illustration shows a diagram of the winding profile of rotor 22 according to an exemplary embodiment, and is generally indicated by reference numeral 120. Figure 2BIn the exemplary embodiment shown, the rotor 22 is a solid cylinder with a plurality of rotor slots 122 evenly spaced along the circumference of the rotor 22. The rotor winding profile 120 includes six rotor winding coils 44, 46, 48, 50, 52, and 54, each rotor winding coil having a first rotor coil loop 124 and a second rotor coil loop 126. The first rotor coil loop 124 and the second rotor coil loop 126 are connected in series. It should be understood that alternative embodiments including more than two rotor coil loops and / or rotor coil loops connected in series and / or in parallel fall within the scope of this disclosure. The first rotor coil loop 124 and the second rotor coil loop 126 include a plurality of wire loops disposed in a pair of rotor slots 122. For example, the first rotor coil loop 124 is disposed in a first rotor slot 128 and a second rotor slot 136. The first rotor slot 128 is separated from the second rotor slot 136 by a third rotor slot 132 and a fourth rotor slot 134. The second rotor coil loop 126 is disposed in a fifth rotor slot 136 and a sixth rotor slot 138. The fifth rotor slot 136 is separated from the sixth rotor slot 138 by the seventh rotor slot 140 and the eighth rotor slot 142. The above-described line configuration is repeated for each of the six rotor winding coils 44, 46, 48, 50, 52, and 54. The rotor 22 has a rotor shaft 144 positioned along its central axis. The rotor shaft 144 is used to rotatably fix the rotor 22 along the central axis 114 of the stator 20. As described above, the rotor shaft 144 also serves to mechanically fix the rotor 22 to a mechanical energy source or mechanical load.

[0046] refer to Figure 3 The illustration shows a schematic diagram of a relay unit 16 connected to the three-phase stator windings 24, 26 according to an exemplary embodiment, and is generally indicated by reference numeral 150. Figure 3 In an exemplary embodiment, the relay unit 16 includes six single-pole double-throw (SPDT) relays 156, 160, 164, 166, 170, and 178 and two single-pole single-throw (SPST) relays 172 and 176. It should be understood that alternative embodiments of the relay unit 16, including relays of alternative configurations, types, and / or numbers, fall within the scope of this disclosure. Furthermore, implementations of the relay unit 16 using electromagnetic relays, solid-state relays, and / or additional types of electronically controllable relays are within the scope of this disclosure.

[0047] The first stator winding coil 28 has a first terminal 152a and a second terminal 152b. The first terminal 152a is connected to the second stator winding coil 30, and the second terminal 152b is connected to the first relay unit output 74. The second stator winding coil 30 has a first terminal 154a and a second terminal 154b. The first terminal 154a is connected to the first terminal 152a of the first stator winding coil 28, and the second terminal 154b is connected to the first relay 156. The third stator winding coil 32 has a first terminal 158a and a second terminal 158b. The first terminal 158a is connected to the first terminal 154a of the second stator winding coil 30, and the second terminal 158b is connected to the second relay 160.

[0048] The first relay 156 has an electrode 156a, a first switching terminal 156b, and a second switching terminal 156c. The electrode 156a is connected to the second terminal 154b of the second stator winding coil 30. The first switching terminal 156b is connected to the output 76 of the second relay unit. The second switching terminal 156c is connected to the output 78 of the third relay unit.

[0049] The second relay 160 has an electrode 160a, a first switching terminal 160b, and a second switching terminal 160c. The electrode 160a is connected to the second terminal 158b of the third stator winding coil 32. The first switching terminal 160b is connected to the output 78 of the third relay unit. The second switching terminal 160c is connected to the output 76 of the second relay unit.

[0050] The fourth stator winding coil 34 has a first terminal 162a and a second terminal 162b. The first terminal 162a is connected to the third relay 164, and the second terminal 162b is connected to the fourth relay 166. The fifth stator winding coil 36 has a first terminal 168a and a second terminal 168b. The first terminal 168a is connected to the fifth relay 170, and the second terminal 168b is connected to the sixth relay 172. The sixth stator winding coil 38 has a first terminal 174a and a second terminal 174b. The first terminal 174a is connected to the seventh relay 176, and the second terminal 174b is connected to the eighth relay 178.

[0051] The third relay 164 has an electrode 164a, a first switching terminal 164b, and a second switching terminal 164c. The electrode 164a is connected to the first terminal 162a of the fourth stator winding coil 34. The first switching terminal 164b is connected to the first terminal 168a of the fifth stator winding coil 36. The second switching terminal 164c is connected to the output 74 of the first relay unit.

[0052] The fourth relay 166 has an electrode 166a, a first switching terminal 166b, and a second switching terminal 166c. The electrode 166a is connected to the second terminal 162b of the fourth stator winding coil 34. The first switching terminal 166b is connected to the output 74 of the first relay unit. The second switching terminal 166c is connected to the second terminal 168b of the fifth stator winding coil 36.

[0053] The fifth relay 170 has an electrode 170a, a first switching terminal 170b, and a second switching terminal 170c. The electrode 170a is connected to the first terminal 168a of the fifth stator winding coil 36. The first switching terminal 170b is connected to the first terminal 174a of the sixth stator winding coil 38. The second switching terminal 170c is connected to the output 78 of the third relay unit.

[0054] The sixth relay 172 has a first terminal 172a and a second terminal 172b. The first terminal 172a is connected to the second terminal 168b of the fifth stator winding coil 36. The second terminal 172b is connected to the output 76 of the second relay unit.

[0055] The seventh relay 176 has a first terminal 176a and a second terminal 176b. The first terminal 176a is connected to the first terminal 174a of the sixth stator winding coil 38. The second terminal 176b is connected to the output 76 of the second relay unit.

[0056] The eighth relay 178 has an electrode 178a, a first switching terminal 178b, and a second switching terminal 178c. The electrode 178a is connected to the second terminal 174b of the sixth stator winding coil 38. The first switching terminal 178b is connected to the output 76 of the second relay unit. The second switching terminal 178c is connected to the second terminal 168b of the fifth stator winding coil 36.

[0057] exist Figure 3 In the exemplary embodiment shown, relay unit 16 is configured for eight-pole operation of the doubly-fed induction motor 12. By switching each of the relays 156, 160, 164, 166, 170, 172, 176, 178 in relay unit 16, the three-phase stator windings 24, 26 can be connected for four-pole operation of the doubly-fed induction motor 12, as will be discussed in more detail below.

[0058] refer to Figure 4 The figure illustrates a block diagram of a replaceable system for energy conversion, typically indicated by reference numeral 200. System 200 is similar to... Figure 1 The system 10 is shown, and the same components are indicated by the same reference numerals. However, in system 200, the power conversion unit 14 of system 10 is replaced by a backup power conversion unit 202.

[0059] The alternative power conversion unit 202 is used to convert a direct current (DC) input power supply into two three-phase alternating current (AC) output power supplies, and to supply the three-phase AC power supply to each of the three-phase rotor windings 40, 42. Figure 4 In the exemplary embodiment shown, the alternative power conversion unit 202 includes a fixed power transfer inverter 204, a fixed power transfer coil 206, a rotating power transfer coil 208, a rotating power transfer rectifier 210, a first inverter 68, and a second inverter 70. The alternative power conversion unit 202 also includes a fixed wireless transceiver 212, a rotating wireless transceiver 214, and a rotating controller 216. The alternative power conversion unit 202 is electrically connected to the controller 18 and DC power supplies 72a and 72b.

[0060] A fixed power transfer inverter 204 is used to convert DC power supplies 72a, 72b into alternating current (AC) for wireless power transfer using a fixed power transfer coil 206. In an exemplary embodiment, the fixed power transfer inverter 204 is fixed to the housing (not shown) of the stator 20 or the doubly fed induction motor 12, near the end of the rotor 22. The fixed power transfer inverter 204 is a square wave, modified sine wave, pulsed sine wave, pulse width modulation (PWM) wave, or pure sine wave inverter. It should be understood that other types of inverters or other electrical devices designed to convert direct current (DC) to alternating current (AC) fall within the scope of this disclosure. The fixed power transfer inverter 204 is connected to the DC power supplies 72a, 72b and the fixed power transfer coil 206.

[0061] A fixed power transfer coil 206 is used to wirelessly transfer power from a fixed power transfer inverter 204 to a rotating power transfer rectifier 210. In an exemplary embodiment, the fixed power transfer coil 206 is a coil of a resolver. The fixed power transfer coil 206 is fixed to the housing (not shown) of the stator 20 or the doubly-fed induction motor 12, near one end of the rotor 22. The fixed power transfer coil 206 is connected to the fixed power transfer inverter 204 and is inductively coupled to the rotating power transfer coil 208. The fixed power transfer inverter 204 excites the fixed power transfer coil 206 with a varying current. The varying current induces a varying magnetic field in the vicinity of the fixed power transfer coil 206.

[0062] A rotating power transfer coil 208 is used to wirelessly receive power from a fixed power transfer inverter 204 via a fixed power transfer coil 206. In an exemplary embodiment, the rotating power transfer coil 208 is a coil of a resolver. The rotating power transfer coil 208 is fixed to the rotor 22 (e.g., rotor shaft 144) of the doubly-fed induction motor 12. The rotating power transfer coil 208 is connected to a rotating power transfer rectifier 210 and is inductively coupled to the fixed power transfer coil 206. A changing magnetic field induced by the fixed power transfer coil 206 induces alternating current (AC) in the rotating power transfer coil 208. The alternating current (AC) is converted to direct current (DC) by the rotating power transfer rectifier 210.

[0063] A rotating power transfer rectifier 210 is used to convert alternating current (AC) induced in a rotating power transfer coil 208 into direct current (DC). In an exemplary embodiment, the rotating power transfer rectifier 210 is fixed to the rotor 22 (e.g., rotor shaft 144) of a doubly-fed induction motor 12. The rotating power transfer rectifier 210 is a rectifier, such as a controlled rectifier, an uncontrolled rectifier, a half-wave rectifier, a full-wave rectifier, and / or a bridge rectifier. It should be understood that other types of rectifiers or other electrical devices designed to convert alternating current (AC) to direct current (DC) fall within the scope of this disclosure. The rotating power transfer rectifier 210 is connected to the rotating power transfer coil 208 and to a first inverter 68 and a second inverter 70.

[0064] In an optional exemplary embodiment, capacitive coupling can be used instead of inductive coupling to transfer power from the fixed power transfer inverter 204 to the rotating power transfer rectifier 210. In the alternative exemplary embodiment described above, a fixed conductive electrode (not shown) is fixed to the stator 20 or the housing (not shown) of the doubly-fed induction motor 12, near the end of the rotor 22, and electrically connected to the fixed power transfer inverter 204. A rotating conductive electrode (not shown) is fixed to the rotor 22 of the doubly-fed induction motor 12 (e.g., rotor shaft 144) and electrically connected to the rotating power transfer rectifier 210. The capacitive coupling between the fixed and rotating conductive electrodes allows for wireless power transfer between the fixed power transfer inverter 204 and the rotating power transfer rectifier 210.

[0065] Inverters 68 and 70 convert direct current (DC) to alternating current (AC) and allow controller 18 to control various characteristics of the AC power. In a non-limiting example, inverters 68 and 70 are fixed to the rotor 22 (e.g., rotor shaft 144) of a doubly-fed induction motor 12. Inverters 68 and 70 respond to data signals from rotation controller 216 by adjusting the amplitude, frequency, and / or phase angle of the AC current and / or voltage output. Inverters 68 and 70 receive DC power from rotation power transfer rectifier 210 and supply AC power to each of rotor winding terminals 56, 58, 60, 62, 64, and 66. Inverters 68 and 70 are also electrically connected to rotation controller 216. In an exemplary embodiment, inverters 68 and 70 are square wave, modified sine wave, pulsed sine wave, pulse width modulation (PWM) wave, or pure sine wave inverters. It should be understood that other types of inverters or other electrical devices designed to convert direct current (DC) to alternating current (AC) fall within the scope of this disclosure.

[0066] A fixed wireless transceiver 212 is used to transmit data from the controller 18 to the rotary controller 216. In an exemplary embodiment, the fixed wireless transceiver 212 is fixed to the housing (not shown) of the stator 20 or the doubly fed induction motor 12, near the end of the rotor 22. In another exemplary embodiment, the fixed wireless transceiver 212 is located within the controller 18. The fixed wireless transceiver 212 is a device capable of wirelessly transmitting and receiving data, such as a WiFi transceiver, a Bluetooth transceiver, and / or an RF transceiver, or similar devices. It should be understood that various other types and protocols of wireless data transmission fall within the scope of this disclosure.

[0067] Rotation controller 216 receives data from controller 18 using rotational wireless transceiver 214. In an exemplary embodiment, rotational wireless transceiver 214 is fixed to the rotor 22 of doubly-fed induction motor 12 (e.g., rotor shaft 144). In another exemplary embodiment, rotational wireless transceiver 214 is located within rotation controller 216. Rotational wireless transceiver 214 is a device capable of wirelessly transmitting and receiving data, such as a WiFi transceiver, Bluetooth transceiver, and / or RF transceiver, or similar devices. It should be understood that various other types and protocols of wireless data transmission fall within the scope of this disclosure.

[0068] Rotary controller 216 is used to process and act on data received by rotary wireless transceiver 214. Rotary controller 216 is similar to controller 18 and also includes a processor (not shown) and a medium (not shown), as discussed above with reference to controller 18. Rotary controller 216 is electrically connected to rotary wireless transceiver 214, first inverter 68, and second inverter 70. In a non-limiting example, rotary controller 216 may receive data from controller 18 containing instructions to adjust the amplitude, frequency, and / or phase angle of the AC current and / or voltage output of the first inverter 68 and the second inverter 70.

[0069] In an exemplary embodiment, system 10 and / or system 200 serve as an aircraft generator in the aircraft. Rotor shaft 144 is mechanically fixed to the rotating component of the aircraft's jet engine, providing rotational energy to rotor 22. The aircraft's DC power supply provides DC power 72a, 72b to power conversion unit 14 and / or alternative power conversion unit 202. Relay unit outputs 74, 76, 78 are connected to the aircraft's three-phase AC power system, which has multiple electrical loads. Providing power with a narrow bandwidth to the three-phase AC power system is advantageous. The rotational speed of the jet engine, and therefore the rotational speed of rotor shaft 144, can vary during aircraft operation; therefore, the operation of the doubly-fed induction motor 12 must be regulated to adjust the voltage amplitude and frequency of the output power.

[0070] In order to adjust the voltage amplitude of the output power, the controller 18 is connected to the inverters 68 and 70 to increase or decrease the excitation current amplitude of the three-phase rotor windings 40 and 42, thereby adjusting the voltage amplitude of the output power.

[0071] To regulate the frequency of the output power, the medium 82 of the controller 18 contains software instructions (i.e., the controller 18 is programmed) to determine the rotational speed of the rotor shaft 144 and to regulate the operation of the doubly-fed induction motor 12 based on the rotational speed of the rotor shaft 144. In a non-limiting example, the rotational speed of the rotor shaft 144 is determined using a solver, which is a rotary transducer used to measure rotational speed. In another non-limiting example, a rotary or pulse encoder is used to determine the rotational speed of the rotor shaft 144. It should be understood that various other devices and methods that can be used by the controller 18 to determine the rotational speed of the rotor shaft 144 fall within the scope of this disclosure.

[0072] To regulate the operation of the doubly-fed induction motor 12 based on the rotational speed of the rotor shaft 144, the medium 82 of the controller 18 contains software instructions (i.e., the controller 18 is programmed) to adjust the excitation frequency of the three-phase rotor windings 40, 42, and / or adjust the number of poles of the doubly-fed induction motor 12 (i.e., the number of magnetic poles induced by the current flowing through the three-phase rotor windings 40, 42). To adjust the excitation frequency of the three-phase rotor windings 40, 42, the controller 18 communicates with the inverters 68, 70 of the power conversion unit 14 and / or the alternative power conversion unit 202 using the wired or wireless communication method described above, to command the inverters 68, 70 to increase or decrease the excitation frequency of the three-phase rotor windings 40, 42. To adjust the number of poles, controller 18 communicates with inverters 68, 70 of power conversion unit 14 and / or alternative power conversion unit 202 using the wired or wireless communication method described above, to command inverters 68, 70 to adjust multiple phase angles of the excitation of three-phase rotor windings 40, 42. Controller 18 is also communicated with relay unit 16 to connect three-phase stator windings 24, 26 for eight-pole or four-pole operation of doubly-fed induction motor 12, as described above.

[0073] refer to Figure 5 Figure 300 illustrates the operating modes of system 10 and / or system 200 according to exemplary embodiments, and is generally indicated by reference numeral 300. The vertical axis 302 of Figure 300 represents the electrical frequency in Hertz (Hz). The horizontal axis 304 of Figure 300 represents the rotational speed of rotor shaft 144 in thousands of revolutions per minute (krpm). The first line 306 is the frequency of the output power based on the rotational speed of rotor shaft 144. The second line 308 is the excitation frequency of the three-phase rotor windings 40, 42, wherein the doubly-fed induction motor 12 operates in an eight-pole mode. The third line 310 is the excitation frequency of the three-phase rotor windings 40, 42, wherein the doubly-fed induction motor 12 operates in a four-pole mode. For the second line 308 and the third line 310, a negative excitation frequency means that the magnetic field generated by the three-phase rotor windings 40, 42 rotates in the opposite direction to the mechanical rotation of rotor shaft 144.

[0074] In an exemplary embodiment, the excitation frequencies of the three-phase rotor windings 40 and 42 and the number of poles for operating the doubly-fed induction motor 12 are determined using the following formula:

[0075]

[0076] Among them, f 定子绕组 It is the frequency of the output power (i.e., 306 for the first line), f 转子绕组 is the excitation frequency of the three-phase rotor windings 40, 42 (i.e., the second line 308 and the third line 310), P is the number of poles of the doubly-fed induction motor 12 (e.g., four or eight), and V RThe rotational speed of the rotor shaft 144 is measured in revolutions per minute (rpm).

[0077] exist Figure 5 In the exemplary embodiment depicted, the number of poles switches from eight to four when the rotor shaft 144 rotates at 8 krpm. It should be understood that alternative embodiments may use other pole switching combinations (e.g., twelve to six or four to two). To operate the doubly-fed induction motor 12 in eight-pole mode, the controller 18 commands the inverters 68 and 70 to excite the first rotor winding coil 44 and the fourth rotor winding coil 50 with a first sinusoidal current, the second rotor winding coil 46 and the fifth rotor winding coil 52 with a second sinusoidal current, and the third rotor winding coil 48 and the sixth rotor winding coil 54 with a third sinusoidal current. The second sinusoidal current lags the first sinusoidal current by 120 degrees. The third sinusoidal current lags the second sinusoidal current by 120 degrees. The controller 18 also commands the relay unit 16 to connect the three-phase stator windings 24 and 26 for eight-pole operation.

[0078] To configure the relay unit 16 for eight-pole operation, the first relay 156 connects terminal 156a to the first switching terminal 156b. The second relay 160 connects terminal 160a to the first switching terminal 160b. The third relay 164 connects terminal 164a to the first switching terminal 164b. The fourth relay 166 connects terminal 166a to the first switching terminal 166b. The fifth relay 170 connects terminal 170a to the first switching terminal 170b. The sixth relay 172 connects the first terminal 172a to the second terminal 172b. The seventh relay 176 disconnects the first terminal 176a from the second terminal 176b. The eighth relay 178 connects terminal 178a to the first switching terminal 178b.

[0079] To operate the doubly-fed induction motor 12 in four-pole mode, the controller 18 commands the first inverter 68 to excite the first rotor winding coil 44 with a fourth sinusoidal current, the second rotor winding coil 46 with a fifth sinusoidal current, and the third rotor winding coil 48 with a sixth sinusoidal current. The controller 18 also commands the second inverter 70 to excite the fourth rotor winding coil 50 with a seventh sinusoidal current, the fifth rotor winding coil 52 with an eighth sinusoidal current, and the sixth rotor winding coil 54 with a ninth sinusoidal current. The fifth sinusoidal current lags the fourth sinusoidal current by 240 degrees. The sixth sinusoidal current lags the fourth sinusoidal current by 120 degrees. The seventh sinusoidal current differs from the fourth sinusoidal current by 180 degrees. The eighth sinusoidal current differs from the fifth sinusoidal current by 180 degrees. The ninth sinusoidal current differs from the sixth sinusoidal current by 180 degrees. The controller 18 also commands the relay unit 16 to connect the three-phase stator windings 24 and 26 for four-pole operation.

[0080] To configure relay unit 16 for four-pole operation, first relay 156 connects terminal 156a to second switching terminal 156c. Second relay 160 connects terminal 160a to second switching terminal 160c. Third relay 164 connects terminal 164a to second switching terminal 164c. Fourth relay 166 connects terminal 166a to second switching terminal 166c. Fifth relay 170 connects terminal 170a to second switching terminal 170c. Sixth relay 172 disconnects first terminal 172a from second terminal 172b. Seventh relay 176 connects first terminal 176a to second terminal 176b. Eighth relay 178 connects terminal 178a to second switching terminal 178c.

[0081] In another exemplary embodiment, the doubly-fed induction motor 12 is used as a motor to provide rotational energy to the jet engine of an aircraft during the start-up process of the jet engine. In yet another exemplary embodiment, system 10 or system 200 is used in a vehicle such as an automobile, and rotor shaft 144 is connected to the vehicle's drivetrain (e.g., using a transmission, gearbox, and / or other means of transmitting mechanical power). It should be understood that additional uses of systems 10, 200, and / or the doubly-fed induction motor 12 for converting energy are included within the scope of this disclosure.

[0082] The systems 10 and 200 disclosed herein offer several advantages. When used as generators, the frequency of the output power can be precisely regulated. Figure 5 In the exemplary embodiment depicted, the output frequency is maintained between 360Hz and 440Hz over a wide speed range of the rotor shaft 144. Furthermore, because the excitation frequency of the three-phase rotor windings 40, 42 is much lower than the frequency of the power induced in the three-phase stator windings 24, 26, the inverters 68, 70 only need to be rated for a small fraction of the power output of the systems 10, 200, as given by the following formula:

[0083]

[0084] Among them, P 定子绕组 The power P generated at points 24 and 26 of the three-phase stator windings 转子绕组 This is the power supplied to the three-phase rotor windings 40 and 42, f 定子绕组 It is the frequency of the output power, and f 转子绕组 It is the excitation frequency of rotor windings 40 and 42.

[0085] In addition, systems 10 and 200 can immediately cut off power in an emergency by disabling inverters 68 and 70. Even if rotor 22 is still rotating, disabling inverters 68 and 70 will stop power generation.

[0086] The description in this disclosure is exemplary in nature only, and variations thereof without departing from the spirit and scope of this disclosure are intended to be within the scope of this disclosure. Such variations should not be considered as departing from the spirit and scope of this disclosure.

Claims

1. A system for converting energy, the system comprising: Doubly fed induction motor, comprising: A rotor having multiple rotor windings; and The stator has multiple stator windings; A power conversion unit electrically connected to the plurality of rotor windings, wherein the power conversion unit is configured to excite the plurality of rotor windings with alternating current; A relay unit electrically connected to the plurality of stator windings, wherein the relay unit is configured to electrically interconnect a plurality of terminals of the plurality of stator windings; and A controller, electrically connected to the power conversion unit and the relay unit, wherein the controller is programmed to: Determine the rotational speed of the rotor; and The operation of the doubly-fed induction motor is adjusted based on the rotational speed of the rotor in the following manner: The power conversion unit is used to excite the plurality of rotor windings in a first phase configuration or a second phase configuration, wherein the first phase configuration is used to provide a first number of active poles, and the second phase configuration is used to provide a second number of active poles; and The relay unit is used to electrically interconnect one or more terminals of a plurality of terminals of the plurality of stator windings in a first connection configuration or a second connection configuration, wherein the first connection configuration is used to provide the first number of active poles and the second connection configuration is used to provide the second number of active poles.

2. The system according to claim 1, wherein: The plurality of rotor windings also include: The first three-phase rotor winding has a first rotor winding coil, a second rotor winding coil, and a third rotor winding coil; and The second and third phase rotor windings have a fourth rotor winding coil, a fifth rotor winding coil, and a sixth rotor winding coil. The plurality of stator windings also include: The first three-phase stator winding includes: a first stator winding coil having a first terminal and a second terminal, a second stator winding coil having a first terminal and a second terminal, and a third stator winding coil having a first terminal and a second terminal; and The second three-phase stator winding includes: a fourth stator winding coil having a first terminal and a second terminal; a fifth stator winding coil having a first terminal and a second terminal; and a sixth stator winding coil having a first terminal and a second terminal; and The system also includes: First output terminal, second output terminal, and third output terminal.

3. The system according to claim 2, wherein, The power conversion unit further includes: A first inverter has three outputs, each of which is electrically connected to one of the first rotor winding coil, the second rotor winding coil, or the third rotor winding coil. The second inverter has three outputs, each of which is electrically connected to one of the fourth rotor winding coil, the fifth rotor winding coil, or the sixth rotor winding coil; and The first inverter and the second inverter are configured to be powered by a DC power supply.

4. The system according to claim 3, further comprising: The slip ring is configured to provide electrical communication between each output of the first inverter and one of the first rotor winding coil, the second rotor winding coil, or the third rotor winding coil, and to provide electrical communication between each output of the second inverter and one of the fourth rotor winding coil, the fifth rotor winding coil, or the sixth rotor winding coil.

5. The system according to claim 3, wherein, The relay unit also includes: Multiple solid-state relays are electrically connected to the first three-phase stator winding and the second three-phase stator winding.

6. The system according to claim 3, wherein, To regulate the operation of the doubly-fed induction motor, the controller is also programmed to: When the doubly fed induction motor is used as a generator, the excitation frequency of the first three-phase rotor winding is adjusted using the first inverter of the power conversion unit based on the rotational speed of the rotor, and the excitation frequency of the second three-phase rotor winding is adjusted using the second inverter of the power conversion unit to regulate the output voltage frequency.

7. The system according to claim 3, wherein, To regulate the operation of the doubly-fed induction motor, the controller is also programmed to: When the doubly fed induction motor is used as a generator, the power conversion unit and the relay unit are used to configure the doubly fed induction motor to have four effective poles based on the rotational speed of the rotor in order to regulate the output voltage frequency. as well as When the doubly fed induction motor is used as a generator, the power conversion unit and the relay unit are used to configure the doubly fed induction motor to have eight effective poles based on the rotational speed of the rotor in order to regulate the output voltage frequency.

8. The system according to claim 7, wherein, To configure the doubly-fed induction motor to have four effective poles, the controller is also programmed to: Configure the first inverter as follows: The first rotor winding coil is excited by a first sinusoidal current. The second rotor winding coil is excited by a second sinusoidal current, wherein the second sinusoidal current lags the first sinusoidal current by 240 degrees. The third rotor winding coil is excited by a third sinusoidal current, wherein the third sinusoidal current lags the first sinusoidal current by 120 degrees. Configure the second inverter as follows: The fourth rotor winding coil is excited by a fourth sinusoidal current, wherein the fourth sinusoidal current is 180 degrees out of phase with the first sinusoidal current. The fifth rotor winding coil is excited by a fifth sinusoidal current, wherein the fifth sinusoidal current is 180 degrees out of phase with the second sinusoidal current; The sixth rotor winding coil is excited by a sixth sinusoidal current, wherein the sixth sinusoidal current is 180 degrees out of phase with the third sinusoidal current; and The relay unit is configured as follows: The first terminal of the first stator winding coil is electrically connected to the second output terminal and the first terminal of the sixth stator winding coil; The first terminal of the second stator winding coil is electrically connected to the third output terminal and the first terminal of the fifth stator winding coil; Electrically connect the first terminal of the third stator winding coil to the first output terminal and the first terminal of the fourth stator winding coil; and The second terminal of the fourth stator winding coil is electrically connected to the second terminal of the fifth stator winding coil and the second terminal of the sixth stator winding coil.

9. The system according to claim 7, wherein, The doubly-fed induction motor is configured to have eight effective poles, and the controller is further programmed to: Configure the first inverter as follows: The first rotor winding coil is excited by a first sinusoidal current. The second rotor winding coil is excited by a second sinusoidal current, wherein the second sinusoidal current lags the first sinusoidal current by 120 degrees. The third rotor winding coil is excited by a third sinusoidal current, wherein the third sinusoidal current lags the second sinusoidal current by 120 degrees. Configure the second inverter as follows: The first sinusoidal current is used to excite the fourth rotor winding coil; The fifth rotor winding coil is excited by the second sinusoidal current. The sixth rotor winding coil is excited by the third sinusoidal current; and The relay unit is configured as follows: The first terminal of the first stator winding coil is electrically connected to the third output terminal and the second terminal of the sixth stator winding coil; The first terminal of the second stator winding coil is electrically connected to the second output terminal and the second terminal of the fifth stator winding coil; Electrically connect the first terminal of the third stator winding coil to the first output terminal and the second terminal of the fourth stator winding coil; and The first terminal of the fourth stator winding coil is electrically connected to the first terminal of the fifth stator winding coil and the first terminal of the sixth stator winding coil.

10. A system for converting energy for a vehicle, the system comprising: Doubly fed induction motor, comprising: A rotor having multiple rotor windings, wherein the multiple rotor windings further include: a first three-phase rotor winding having a first rotor winding coil, a second rotor winding coil, and a third rotor winding coil; and a second three-phase rotor winding having a fourth rotor winding coil, a fifth rotor winding coil, and a sixth rotor winding coil; and The stator has multiple stator windings; A power conversion unit electrically connected to the plurality of rotor windings, the power conversion unit further comprising: a first inverter having three outputs and a second inverter having three outputs, wherein each output of the first inverter is electrically connected to one of the first rotor winding coil, the second rotor winding coil, or the third rotor winding coil, wherein each output of the second inverter is electrically connected to one of the fourth rotor winding coil, the fifth rotor winding coil, or the sixth rotor winding coil; A relay unit electrically connected to the plurality of stator windings; and A controller, electrically connected to the power conversion unit and the relay unit, wherein the controller is programmed to: Determine the rotational speed of the rotor; Based on the rotor's rotational speed, the power conversion unit and the relay unit are used to regulate the operation of the doubly-fed induction motor. To regulate the operation of the doubly-fed induction motor, the controller is also programmed to configure the doubly-fed induction motor with four effective poles using the power conversion unit in the following manner: The first inverter is configured to: excite the first rotor winding coil with a first sinusoidal current; excite the second rotor winding coil with a second sinusoidal current, wherein the second sinusoidal current lags the first sinusoidal current by 240 degrees; and excite the third rotor winding coil with a third sinusoidal current, wherein the third sinusoidal current lags the first sinusoidal current by 120 degrees; and The second inverter is configured to: excite the fourth rotor winding coil with a fourth sinusoidal current, wherein the fourth sinusoidal current is 180 degrees out of phase with the first sinusoidal current; excite the fifth rotor winding coil with a fifth sinusoidal current, wherein the fifth sinusoidal current is 180 degrees out of phase with the second sinusoidal current; and excite the sixth rotor winding coil with a sixth sinusoidal current, wherein the sixth sinusoidal current is 180 degrees out of phase with the third sinusoidal current.

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