Independent speed-regulating variable-frequency generator system and independent speed-regulating variable-frequency power generation method

Abstract

The present application relates to an independent speed-adjustable variable frequency generator system and a method for independent speed-adjustable variable frequency power generation. An independent speed-adjustable variable frequency generator system is described, which may include a rotor and a stator. The system may also include a pilot generator stage, which includes a magnetic field source located on the rotor and a group of pilot multi-phase windings located on the stator. The system may also include a high-frequency transformer stage, which includes a first group of high-frequency transformer multi-phase windings located on the stator and a second group of high-frequency transformer multi-phase windings located on the rotor. The system may also include a host stage, which includes a group of main magnetic field multi-phase windings located on the rotor and a group of main armature multi-phase windings located on the stator, wherein the second group of high-frequency transformer multi-phase windings is directly connected to the group of main magnetic field multi-phase windings. The system may include a generator control unit.

Description

Technical Field

[0001] The present disclosure relates generally to the field of generators, and more particularly to externally modulated independent speed variable frequency generators. Background Art

[0002] In a typical AC power generation system, the frequency of the generated AC power signal depends on the rotational frequency of the rotor of the power generation system. Likewise, in a multi-phase AC power generation system, the frequency of each phase of the power signal depends on the rotational frequency of the rotor.

[0003] An independent variable speed frequency (ISVF) generator enables the generation of an AC electric power signal having a frequency that is independent of the rotor speed. To achieve the independent frequency, the AC power signal generated during the pilot stage may be sent back to the rotor of the ISVF generator. The power may then be modulated and used to generate a second magnetic flux at the rotor that rotates relative to the rotor. The second magnetic flux may be used to generate a main machine stage power signal for distribution. The frequency of the main machine stage power signal may depend on both the rotational frequency of the rotor and the rotational frequency of the second magnetic flux. Thus, the frequency is independent of the rotational frequency of the rotor alone. The ISVF generator also enables the control of other parameters (e.g., magnitude and phase) of the main machine stage power signal.

[0004] Including a modulation stage (e.g., rectifier circuit, inverter circuit, or other circuit) on the rotor of the generator may increase the costs associated with the design and manufacture of a stand-alone variable speed variable frequency generator device. In addition, the strong rotational forces on the rotor may cause the life of the electronic components used to implement the rectifier circuit and inverter circuit to be reduced. There may be other disadvantages. Summary of the invention

[0005] An externally modulated ISVF generator system is disclosed that addresses one or more of the above-mentioned disadvantages. Specifically, the ISVF generator system described herein may perform a modulation function external to the rotor of the ISVF generator. A high-frequency modulated multiphase power signal may be generated external to the rotor, transmitted to the rotor, and used directly to drive the main engine stage of the ISVF generator. Thus, the rotor may not include any modulation circuitry.

[0006] In an embodiment, an independent speed-regulated variable frequency generator system includes a rotor and a stator. The system also includes a pilot generator stage, which includes a magnetic field source located on the rotor and a group of pilot multiphase windings located on the stator. The system also includes a high-frequency transformer stage, which includes a first group of high-frequency transformer multiphase windings located on the stator and a second group of high-frequency transformer multiphase windings located on the rotor. The system includes a host stage, which includes a group of main field multiphase windings located on the rotor and a group of main armature multiphase windings located on the stator, wherein the second group of high-frequency transformer multiphase windings is directly connected to the group of main field multiphase windings. The system also includes a generator control unit.

[0007] In some embodiments, the generator control unit includes a multiphase inverter having a plurality of switch circuits and a controller circuit, and the input end of each of the plurality of switch circuits is connected to the controller circuit. In some embodiments, in the motor state, the controller circuit is configured to disconnect each of the plurality of switch circuits to prevent output at the multiphase inverter. In some embodiments, in the power generation state, the controller circuit is configured to open and close the plurality of switch circuits in a manner to generate a high-frequency modulated multiphase power signal, the high-frequency modulated multiphase power signal including a main magnetic field multiphase power signal component that can be used to drive the set of main magnetic field multiphase windings to generate a rotating magnetic flux that rotates relative to the rotor.

[0008] In some embodiments, the system includes a frequency sensor connected to the output of the multi-phase inverter, wherein the controller circuit is configured to adjust the frequency of the main magnetic field multi-phase power signal component based on the difference between the reference frequency and the main magnetic field frequency measured by the frequency sensor. In some embodiments, the system includes a voltage sensor connected to the output of the set of main armature multi-phase windings, wherein the controller circuit is configured to adjust the voltage of the main magnetic field multi-phase power signal component based on the difference between the reference voltage and the output voltage measured by the voltage sensor. In some embodiments, the system includes an encoder configured to detect the rotational frequency of the rotor, wherein the controller circuit is configured to adjust the frequency of the main magnetic field multi-phase power signal component based on the difference between the reference frequency and the rotor frequency measured by the encoder.

[0009] In some embodiments, the system includes: an external power source; and a first switch circuit configured to open and close the connection between the pilot generator stage and the generator control unit and to open and close the connection between the external power source and the generator control unit. In some embodiments, the system includes: a motor starter drive; and a second switch circuit configured to open and close the connection between the fourth set of multi-phase windings and the power distribution bus and to open and close the connection between the fourth set of multi-phase windings and the motor starter drive.

[0010] In an embodiment, a method for independent speed-regulated variable frequency power generation includes: generating a high-frequency modulated multiphase power signal at a generator control unit located outside the rotor of the independent speed-regulated variable frequency generator, the high-frequency modulated multiphase power signal including a main magnetic field multiphase power signal component. The method also includes: transmitting the high-frequency multiphase power signal from the stator of the independent speed-regulated variable frequency generator to the rotor via a high-frequency transformer stage. The method also includes: generating an asynchronous rotating magnetic flux at the main magnetic field multiphase winding by applying the main magnetic field multiphase power signal component of the high-frequency modulated multiphase power signal to a set of main magnetic field multiphase windings located on the rotor. The method also includes: converting the asynchronous rotating magnetic flux into a host multiphase power signal at a set of main armature multiphase windings located on the stator.

[0011] In some embodiments, the method includes: connecting a set of leading multi-phase windings located on the stator to a multi-phase rectifier of a generator control unit; generating a synchronous rotating magnetic flux that rotates synchronously with the rotor at a magnetic field source located on the rotor; using the set of leading multi-phase windings to convert the synchronous rotating magnetic flux into a leading multi-phase power signal; rectifying the leading multi-phase power signal at the generator control unit to generate a rectified power signal; and using the rectified power signal to generate a high-frequency modulated multi-phase power signal.

[0012] In some embodiments, the method includes: connecting an external power source to a generator control unit; and using a power signal from the external power source to generate a high-frequency modulated multi-phase power signal. In some embodiments, the step of generating a high-frequency modulated multi-phase power signal includes: opening and closing a plurality of switch circuits of a multi-phase inverter in a manner that generates a high-frequency modulated multi-phase power signal at a controller circuit of the generator control unit.

[0013] In some embodiments, the method includes: connecting a motor starting drive to the set of main armature multi-phase windings before generating a high-frequency modulated multi-phase power signal; disconnecting the multiple switching circuits to prevent output at the multi-phase inverter; and sending a current pattern from the motor starting drive through the set of main armature multi-phase windings to generate a rotating flux pattern that causes the rotor to rotate, thereby starting the engine.

[0014] In some embodiments, the method includes: disconnecting the set of main armature multi-phase windings from a motor starter drive after engine starting; and connecting the set of main armature multi-phase windings to a power distribution bus.

[0015] In some embodiments, the method includes: receiving a main magnetic field frequency signal; receiving a reference frequency signal; and adjusting the frequency of a main magnetic field multiphase power signal component of a high-frequency modulated multiphase power signal based on a difference between the main magnetic field frequency signal and the reference frequency signal. In some embodiments, the method includes: receiving an output voltage signal; receiving a reference voltage signal; and adjusting the voltage of a main magnetic field multiphase power signal component of a high-frequency modulated multiphase power signal based on a difference between the reference voltage and the output voltage. In some embodiments, the method includes: receiving a rotor frequency signal; receiving a reference frequency signal; and adjusting the frequency of a main magnetic field multiphase power signal component of a high-frequency modulated multiphase power signal based on a difference between the rotor frequency signal and the reference frequency signal.

[0016] In an embodiment, an independent speed-regulating variable-frequency generator system includes a rotor and a stator. The system also includes: a high-frequency transformer stage, which includes a first set of high-frequency transformer multi-phase windings located on the stator and a second set of high-frequency transformer multi-phase windings located on the rotor. The system also includes: a host stage, which includes a set of main magnetic field multi-phase windings located on the rotor and a set of main armature multi-phase windings located on the stator, wherein the second set of high-frequency transformer multi-phase windings is directly connected to the set of main magnetic field multi-phase windings.

[0017] In some embodiments, the system includes: a generator control unit configured to generate a high-frequency modulated multi-phase power signal, the high-frequency modulated multi-phase power signal including a main magnetic field multi-phase power signal component that can be used to drive the set of main magnetic field multi-phase windings to generate an asynchronous rotating magnetic flux relative to the rotor rotation. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 is a schematic block diagram depicting an embodiment of an externally modulated stand-alone variable speed variable frequency generator system.

[0019] Figure 2 is a schematic block diagram depicting an embodiment of a pulse width modulation frequency converter.

[0020] Figure 3 is a block diagram depicting an embodiment of a signal control system for a stand-alone variable speed AC generator system.

[0021] Figure 4 is a flow chart depicting an embodiment of a method for externally modulated independent variable speed power generation.

[0022] Figure 5 is a flow chart depicting an embodiment of a method for externally modulated independent variable speed power generation.

[0023] Figure 6 is a flow chart depicting an embodiment of a method of operating an externally modulated stand-alone variable speed variable frequency generator system as a starter.

[0024] Although the present disclosure is susceptible to various modifications and alternative forms, specific embodiments are shown as examples in the drawings and will be described in detail herein. However, it should be understood that the present disclosure is not intended to be limited to the specific forms disclosed. On the contrary, the present invention is intended to cover all modifications, equivalents and substitutes that fall within the scope of the present disclosure. DETAILED DESCRIPTION

[0025] As described above, the ISVF generator enables the generation of a multiphase power signal having a frequency that is independent of the rotational frequency of the generator rotor. A non-limiting example of an ISVF device is described in U.S. Patent Application No. 15 / 819,919, filed on November 21, 2017, entitled “Independent Speed ​​Variable Frequency Alternating Current Generator.” Another non-limiting example of a system including an ISVF generator device as both a generator and a starter is described in U.S. Patent Application No. 15 / 872,383, filed on January 16, 2018, entitled “System and Method for Operating an Independent Speed ​​Variable Frequency Generator as a Starter.” Another non-limiting example of a system including an ISVF generator device is described in U.S. Patent Application No. 15 / 866,064, filed on January 9, 2018, entitled “Independent Speed ​​Variable Frequency Based Electrified Propulsion System Architecture.” Each of the above-listed patent applications is incorporated herein by reference in its entirety.

[0026] Reference Figure 1 , describes an embodiment of an externally modulated ISVF generator system 100. The system 100 may include a rotor 102 and a stator 104. The rotor 102 may be configured to rotate relative to the stator 104 to generate power in stages as described herein. The system 100 may include a pilot stage 106, a high frequency transformer stage 108, and a main stage 110.

[0027] The pilot stage may include a magnetic field source 112 coupled to the rotor 102 and a first set of multi-phase windings 114 (also referred to as a pilot set of multi-phase windings to distinguish the first set of multi-phase windings 114 from other sets of multi-phase windings of the system 100). Figure 1As depicted in , the first set of multiphase windings 114 can be configured to generate a 3-phase power signal. However, the present disclosure is not limited to a 3-phase system. More or less than 3 phases are also possible. In addition, the magnetic field source 112 can include a permanent magnet or another type of magnetic source, such as a set of induction generator windings.

[0028] The high frequency transformer stage 108 may include a second set of multi-phase windings 116 (also referred to as a first set of high frequency multi-phase windings) and a third set of multi-phase windings 118 (also referred to as a second set of high frequency multi-phase windings). The second set of multi-phase windings 116 and the third set of multi-phase windings 118 may be configured such that a high frequency modulated power signal is transmitted from the stator 104 to the rotor 102. As used herein, the term "high frequency modulation" means a signal having a modulated component whose frequency exceeds the rotational frequency of the rotor 102.

[0029] The main stage 110 may include a fourth set of multi-phase windings 120 (also referred to as main field multi-phase windings) and a fifth set of multi-phase windings 122 (also referred to as main armature multi-phase windings). Figure 1 , the second set of multi-phase windings 118 may be directly coupled to a set of main field multi-phase windings 120. As used herein, direct coupling means that there is no intermediate modulation circuit (e.g., rectifier or inverter) connected between the third set of multi-phase windings 118 (i.e., the second set of high-frequency transformer multi-phase windings) and the fourth set of multi-phase windings 120 (i.e., a set of main field multi-phase windings).

[0030] The system 100 may also include a generator control unit 124. The generator control unit 124 may include a pulse width modulation inverter 126 and a controller circuit 128. The pulse width modulation inverter 126 is further described herein. The controller circuit 128 may be configured to control the pulse width modulation inverter 126 to modulate and convert the multi-phase power signal to generate a high frequency modulated multi-phase power signal for transmission via the second set of multi-phase windings 116 and the third set of multi-phase windings 118.

[0031] The controller circuit 128 may include any logic circuit or processor (e.g., a microprocessor) with associated software to perform control functions as described herein. For example, in some embodiments, the controller circuit 128 may include a central processing unit (CPU), a graphics processing unit (GPU), a digital signal processor (DSP), a peripheral interface controller (PIC), another type of microprocessor, and / or a combination thereof. The controller circuit 128 may be implemented as an integrated circuit, a field programmable gate array (FPGA), an application specific integrated circuit (ASIC), a combination of logic gate circuits, other types of digital or analog electrical design components, or a combination thereof.

[0032] The system 100 may include a feedback sensor to enable the controller circuit 128 to perform control functions related to generating a high-frequency modulated multiphase power signal. For example, the system 100 may include a frequency sensor 130 connected to the output of the pulse width modulation inverter 126. The frequency sensor 130 may be configured to detect the frequency of the multiphase power signal component of the high-frequency modulated multiphase power signal generated by the pulse width modulation inverter 126. Based on the difference between the measured frequency and a reference frequency (e.g., the desired frequency output of the power signal generated by the host stage 110), the controller circuit 128 may adjust the pulse width modulation inverter 126 to achieve the reference frequency.

[0033] The system 100 may also include a voltage sensor 132 connected to the output of the set of main armature multiphase windings 122. The voltage sensor 132 may determine the magnitude of the voltage generated by the main stage 110. The measured voltage may also be used by the controller circuit 128 to adjust the magnitude of the voltage of the multiphase power signal component of the high frequency modulated multiphase power signal generated by the pulse width modulation inverter 126 based on the difference between the measured voltage and a reference voltage.

[0034] System 100 may also include encoder 134 positioned proximate rotor 102 and configured to detect a rotational frequency of rotor 102. Rotor 102 rotational frequency may be used by controller circuit 128 to determine a frequency of a multiphase power signal component of a high frequency modulated multiphase power signal generated by pulse width modulation inverter 126.

[0035] The system 100 may include an external power source 136 and a first switching circuit 138. The external power source 136 may include a ground power distribution system, a generator, a battery, or a combination thereof, and may be fixed or movable relative to the system 100. The first switching circuit 138 may be configured to open and close the connection between the generator control unit 124 and the pilot stage 106 and to open and close the connection between the generator control unit 124 and the external power source 136. Although Figure 1 The input and output of the first switch circuit 138 are depicted as a single line, it should be understood that the input and output can represent multi-phase power input and output. Specifically, the input and output of the first switch circuit 138 can be configured as a three-phase power signal. The first switch circuit 138 may include a physical switch or a logical switch circuit configured to selectively open and close an electrical connection.

[0036] The system may include a motor starter drive 140, a power distribution bus 142, and a second switch circuit 144. The motor starter drive 140 may include a circuit configured to apply a current pattern to the motor so as to cause the engine to turn over and start. For example, the motor starter drive 140 may be configured to apply a field oriented control (FOC) signal to the set of main armature multi-phase windings 122, or generate a direct torque control (DTC) signal to the set of main armature multi-phase windings 122. The motor starter drive 140 may include different types of variable frequency motor drive (VFMD) topologies. The second switch circuit 144 may be configured to open and close the connection between the motor starter drive 140 and the set of main armature multi-phase windings 122 and to open and close the connection between the power distribution bus 142 and the set of main armature multi-phase windings 122. As with the first switch circuit 138, although Figure 1 The input and output of the second switch circuit 144 are depicted as a single line, it being understood that the input and output may represent multi-phase power input and output. The second switch circuit 144 may include a physical switch or a logical switch circuit configured to selectively open and close an electrical connection.

[0037] During operation, the system 100 can operate in different states or modes of operation. In a first state, the system 100 can be configured to generate power based on the rotation of the rotor 102 by a prime mover (e.g., an engine). In a second state, the system 100 can be configured to generate or convert power based on power received from an external power source 136. In a third state, the system 100 can be configured to act as a motor or starter to start the engine. Other states or combinations of states are also possible.

[0038] When in the first state, the first switching circuit can be configured to close the connection between the first set of multi-phase windings 114 and the generator control unit 124 (ie, connect) and disconnect the connection between the external power supply 136 and the generator control unit 124 (ie, disconnect).

[0039] A prime mover (e.g., a vehicle engine) may rotate the rotor 102, causing the magnetic field source 112 attached to the rotor 102 to also rotate, thereby generating magnetic flux at the lead stage 106. The rotating magnetic flux may be used to generate a lead multiphase power signal at the first set of multiphase windings 114. Since the rotational frequency of the rotating magnetic flux depends on the rotational frequency of the rotor 102, the rotating magnetic flux may be considered synchronous, meaning that the magnetic flux is synchronized with the rotor 102. The lead multiphase power signal may be used as an input to a pulse width modulated frequency converter 126 of a generator control unit 124.

[0040] The controller circuit 128 may rely on feedback received from the frequency sensor 130, the voltage sensor 132, and the encoder 134 to generate a high-frequency modulated multiphase power signal including a high-frequency modulation component and a low-frequency multiphase power signal component. The high-frequency modulated multiphase power signal may be transmitted from the second set of multiphase windings 116 on the stator 104 to the third set of multiphase windings 118 on the rotor 102.

[0041] The fourth set of multiphase windings 120 can be directly coupled to the third set of multiphase windings 118. Thus, the high frequency modulated multiphase power signal can be directly transmitted to the fourth set of multiphase windings 120. Due to the inherent inductance exhibited by the third set of multiphase windings 118 and the fourth set of multiphase windings 120, the high frequency modulated component of the high frequency modulated multiphase power signal can be filtered out, leaving only the multiphase power signal component. In some embodiments, additional circuitry can be included to filter the high frequency modulated component. The remaining multiphase power signal component can drive the current at the fourth set of multiphase windings 120, thereby generating magnetic flux.

[0042] The controller circuit 128 may signal the pulse width modulation inverter 126 to generate a multiphase power signal component having a frequency that causes the magnetic flux at the fourth set of multiphase windings 120 to rotate relative to the rotor 102. Therefore, the frequency of the rotating magnetic flux at the fourth set of multiphase windings 120 is a combination of the rotational frequency of the rotor 102 and the frequency of the rotating magnetic flux at the fourth set of multiphase windings 120. The rotating magnetic flux may be asynchronous because its rotational frequency does not depend solely on the rotational frequency of the rotor 102. In other words, the rotating magnetic flux may be asynchronous with the rotor 102.

[0043] The rotating magnetic flux may be used to generate a main stage multi-phase power signal at the fifth set of multi-phase windings 122. The main stage multi-phase power signal may be distributed via the power distribution bus 142. As such, the frequency, voltage, and phase of the power signal at the power distribution bus 142 may be controlled by the generator control unit 124 and may be independent of the rotational frequency of the rotor 102.

[0044] When in the second state, the first switch circuit 138 can be configured to open the connection between the first set of multi-phase windings 114 and the generator control unit 124 (i.e., disconnect) and close the connection between the external power source 136 and the generator control unit 124 (i.e., connect). In this state, the external power source 136 can drive the pulse width modulation inverter 126 instead of the pilot stage 106. The system 100 then acts as a power converter to convert the frequency, voltage, phase, or any combination thereof into a multi-phase power signal having parameters specific to the distribution bus 142.

[0045] When in the third state, the second switching circuit 144 can be configured to close the connection (i.e., connect) between the motor starting drive 140 and the fifth group of multi-phase windings 122 (i.e., a group of main armature multi-phase windings) and disconnect the connection (i.e., disconnect) between the distribution bus 142 and the fifth group of multi-phase windings 122.

[0046] In this state, the controller circuit 128 may prevent output at the pulse width modulation inverter 126. Then, the third set of multi-phase windings 118 and the fourth set of multi-phase windings 120 may operate as an induction motor. The motor starter drive 140 may be configured to send a current pattern through the fifth set of multi-phase windings 122 to generate a rotating flux pattern that interacts with the fourth set of multi-phase windings 120 and causes the rotor 102 to rotate. As the rotor 102 rotates, the engine may be started.

[0047] A benefit of the system 100 is that the modulation and conversion of the multi-phase power signal used to drive a set of main field multi-phase windings can occur outside of the rotor 102. This limits the number of electronic components that can be located on the rotor 102, resulting in a longer life and less complexity for the rotor 102. Other benefits and advantages may exist.

[0048] Reference Figure 2 , depicting an embodiment of a pulse width modulation inverter 126. The pulse width modulation inverter 126 may include a rectifier 210 and an inverter 220. The rectifier 210 may include a first set of diodes 211, 213, 215 and a second set of diodes 212, 214, 216. Each of the first set of diodes 211, 213, 215 may be paired with a corresponding diode in the second set of diodes 212, 214, 216, and each pair is used to rectify a single phase of the input multiphase power signal 230. For example, the diode 211 may be paired with the diode 212, the diode 213 may be paired with the diode 214, and the diode 215 may be paired with the diode 216.

[0049] It should be noted that although Figure 2 While rectifier 210 is depicted as performing three-phase rectification, it may rectify more or less than three phases. Figure 2 Only one embodiment of a rectifier topology is depicted. As will be appreciated by one of ordinary skill in the art having the benefit of this disclosure, other topologies may be used.

[0050] The inverter 220 may include a first set of switches 221, 223, 225 and a second set of switches 222, 224, 226. Each of the first set of switches 221, 223, 225 may be paired with a corresponding switch in the second set of switches 222, 224, 226, and each pair is used to generate a phase of the high-frequency modulated multi-phase power signal 232. For example, the switch 221 may be paired with the switch 222, the switch 223 may be paired with the switch 224, and the switch 225 may be paired with the switch 226. The controller circuit 128 (shown in FIG. Figure 1 ) can be connected to each input terminal of switches 221-226.

[0051] The capacitor 228 may maintain the DC voltage level of the rectified DC power signal during operation. The output of the inverter 220 may be connected to the frequency sensor 130 .

[0052] During power generation, the input of each of the switches 221-226 can be operated to modulate the DC power signal from the rectifier 210 to generate a high-frequency modulated multiphase power signal 232. The high-frequency modulated multiphase power signal may include a modulation component (including a high-frequency modulation component) and a multiphase power signal component. The multiphase power signal component may be used to drive the fourth set of multiphase windings 120 (shown in FIG. Figure 1 ) to generate relative to the rotor 102 (shown in Figure 1 )The rotating magnetic flux that rotates.

[0053] In another state, each of the switches 221-226 may be open (i.e., current and voltage are prevented from passing through the switches 221-226). In this state, the multi-phase inverter 220 does not generate an output. This state may be used to convert the system 100 (shown in FIG. 1 ) into a Figure 1 ) operates as a motor.

[0054] In practice, additional components may be included within the switching topology of inverter 220. For example, each of switches 221-226 may include a switch-diode pair. Furthermore, various types of switches may be used with the present disclosure, including metal oxide semiconductor field effect transistors (MOSFETs), insulated gate bipolar transistors (IGBTs), and / or other types of semiconductor switches. Although Figure 2 Six switches 221 - 226 are depicted, but inverter 220 may include more or less than six in order to generate a multi-phase power signal having a different number of phases.

[0055] A benefit of the pulse width modulated inverter 126 is that it can be located on the stator 104 of the system 100, rather than being attached to the rotor 102. Thus, the rotor can be manufactured at a lower cost, and the components used to construct the pulse width modulated inverter 126 do not need to withstand the strong rotational forces associated with the rotor 102. Other benefits and advantages may exist.

[0056] Reference Figure 3 , depicts a control signal system 300 for an externally modulated ISVF generator. The control signal system 300 is functionally depicted as including summing points 306, 318, 342, absolute value functions 312, 334, and sign function 350. Although depicted functionally, each of these elements may be implemented using structural components. For example, the summing points 306, 318, 342 and the absolute value functions 312, 334 may be implemented as logic hardware (digital logic gates or analog comparison circuits) or in the controller circuit 128 (shown in FIG. Figure 1 ) is software that runs on a processor within the . The hardware associated with these functions is available on Figure 1 The outside of the rotor 102.

[0057] The system 300 may receive a reference frequency signal 302. The reference frequency signal 302 may represent a desired frequency of a multi-phase power distribution system. Specifically, a multi-phase power distribution system may be used in aerospace applications and may provide power to propulsion motors and / or other systems and devices. The reference frequency signal 302 may be "hardwired" to the generator control unit 124 (shown in FIG. Figure 1 ) or may be an adjustable input. For example, the system 300 may be configured to generate a power signal of variable frequency to meet the needs of a particular load. When the load is a motor, the system 300 may output a variable frequency to meet the needs of variable speed. In the case of a desired constant frequency, it may output a fixed frequency. The reference frequency signal 302 may be generated by software running at a processor (e.g., a processor of the generator control unit 124) or by other logic and / or hardware. Therefore, the reference frequency signal 302 may be static or dynamic and may be modified based on a particular load.

[0058] The reference frequency signal 302 may be combined with the rotor frequency signal 304 at a first summing junction 306, and a first intermediate signal 308 may be generated that represents the difference between the reference frequency signal 302 and the rotor frequency signal 304. Conceptually, the first intermediate signal 308 may represent the rotational frequency of the rotating magnetic field relative to the measured rotor 102 (shown in FIG. Figure 1 )’s desired change in rotational frequency.

[0059] As a non-limiting example, the reference frequency signal 302 may be equal to 400 Hz. If the rotor frequency signal 304 is equal to 300 Hz, the first intermediate signal 308 will be equal to 100 Hz, which represents a desired frequency increase relative to the rotational frequency of the rotor 102 (i.e., 300 Hz) in order to equal the reference frequency signal 302 (i.e., 400 Hz).

[0060] The first intermediate signal 308 may be input into an absolute value function 312 to generate a magnitude signal 314 of the first intermediate signal 308. At a second summing point 318, the magnitude signal 314 of the first intermediate signal 308 may be combined with the magnitude signal 316 of the main magnetic field frequency signal 332 (given by Figure 1 The first intermediate signal 308 and the second intermediate signal 320 are combined to generate a second intermediate signal 320. The second intermediate signal 320 may represent the difference between the magnitude of the first intermediate signal 308 and the main magnetic field frequency signal 332. In other words, the second intermediate signal 320 may represent the desired change in the rotational frequency of the main rotating magnetic field relative to the current rotational frequency of the main rotating magnetic field at a set of main stage windings (e.g., the fourth set of multi-phase windings 120). Continuing with the above example, if the main magnetic field frequency signal 332 is equal to 90 Hz, the second intermediate signal 320 will be equal to 10 Hz, which means that the rotational frequency of the rotating magnetic field is relative to the rotor (e.g., Figure 1 of the rotor 102).

[0061] In other words, in the illustrative example, the main rotating magnetic field may rotate at a frequency of 90 Hz relative to the rotor 102, and the rotor 102 may rotate at a frequency of 300 Hz relative to the stator 104. Therefore, the main rotating magnetic field may rotate at a frequency of 390 Hz relative to the stator 104. In order to generate a power signal with a frequency of 400 Hz, the rotation frequency of the main rotating magnetic field will need to be increased by 10 Hz. Therefore, in this example, the second intermediate signal 320 will be equal to 10 Hz.

[0062] The second intermediate signal 320 may be provided to a first proportional-integral-derivative (PID) controller 322. The first PID controller 322 may convert the second intermediate signal 320 into an inverter control signal 324, which instructs the inverter 220 to adjust a multiphase power signal component 328 of a high frequency modulated multiphase power signal of a main stage that is ultimately provided to the rotor. The multiphase power signal component 328 is a current passing through a set of main stage multiphase windings (e.g., Figure 1 When the inverter 220 is connected to the fourth multi-phase winding 120 of the rotor 102, a rotating magnetic field may be generated, wherein the frequency, magnitude, and phase of the rotating magnetic field depend on the frequency, magnitude, and phase of the multi-phase power signal component 328. By adjusting the multi-phase power signal component 328, the inverter 220 may control the rotation of the rotating magnetic field relative to the rotor 102, thereby separating the rotation frequency of the rotating magnetic field from the rotation frequency of the rotor 102. The first PID controller 322 may be Figure 1 Part of the controller circuit 128.

[0063] From the multiphase power signal component 328, a main magnetic field frequency signal 332 may be measured and derived for use as a feedback signal at the second summing junction 318. The main magnetic field frequency signal 332 may be passed through an absolute value function 334 to generate a magnitude signal 316 of the main magnetic field frequency signal 232 used at the second summing junction 318. Typically, the rotor speed encoder 134 may measure and derive a rotor frequency signal 304 based on the rotational frequency of the rotor 102. The rotor frequency signal 304 may be provided as a feedback signal used at the first summing junction 306.

[0064] The first intermediate signal 308 may also be passed to a sign function 350. The sign function 350 may convert the first intermediate signal 308 into a direction signal 352. The direction signal 352 may indicate a desired rotational direction of the rotating magnetic field relative to the rotor 102. A negative direction signal may indicate that the desired rotational frequency is less than the rotational frequency of the rotor 102. A positive direction signal may indicate that the desired rotational frequency is greater than the rotational frequency of the rotor 102. The direction signal 352 may be used by the inverter 220 to control the multi-phase power signal component 328 to achieve the desired rotational direction of the rotating magnetic field relative to the rotor 102.

[0065] The system 300 may also receive a reference voltage signal 338. The reference voltage signal 338 may represent a desired voltage for a multi-phase power distribution system. Specifically, a multi-phase power distribution system may be used in aerospace applications and may provide power to a propulsion motor and / or other systems and devices. The reference voltage signal 338 may be a constant input signal that is "hardwired" into the generator control unit 124, or may be an adjustable input. It may be generated by software running at a processor (e.g., a processor of the generator control unit 124) or by other logic and / or hardware. In an illustrative example, the reference voltage signal 338 may be equal to 105VAC or 230VAC.

[0066] The reference voltage signal 338 may be combined with the stator output voltage signal 340 at a third summing junction 342, and a third intermediate signal 344 may be generated that represents the difference between the reference voltage signal 338 and the stator output voltage signal 340. Conceptually, the third intermediate signal 344 may represent the difference between the primary stator winding (e.g., Figure 1 A desired change in the voltage generated at the fifth set of multi-phase windings 122).

[0067] The third intermediate signal 344 may be provided to a second PID controller 346. The second PID controller 346 may convert the third intermediate signal 340 into an inverter control signal 348, which instructs the inverter 220 to adjust the multi-phase power signal component 328. Specifically, the magnitude of the multi-phase power signal component 328 may be adjusted to increase or decrease the magnitude of the rotating magnetic field, thereby resulting in a higher or lower voltage being generated at the primary stator winding (e.g., the fifth set of multi-phase windings 122). Like the first PID controller 322, the second PID controller 346 may be part of the controller circuit 128.

[0068] Figure 3 The various components described in can be external to the rotor 102 of the system 100. A benefit of the system 300 is that by being external to the rotor 102, the rotational forces applied to the system 300 can be reduced, thereby increasing the life of the system 300. Other benefits and advantages may exist.

[0069] Reference Figure 4 , depicting a method 400 for an embodiment of an externally modulated independent variable speed power generation. The method 400 may include, at 402, generating a high frequency modulated multiphase power signal at a generator control unit located outside a rotor of an independent variable speed power generator. The high frequency modulated multiphase power signal includes a main field multiphase power signal component. For example, the generator control unit 124 may generate the high frequency modulated multiphase power signal.

[0070] The method 400 may further include transmitting the high frequency multiphase power signal from the stator of the independent variable speed generator to the rotor via the high frequency transformer stage at 404. For example, the high frequency modulated multiphase power signal may be transmitted from the stator 104 to the rotor 102 via the high frequency transformer stage 108.

[0071] The method 400 may also include generating an asynchronous rotating flux at a main field multiphase winding by applying a main field multiphase power signal component of a high frequency modulated multiphase power signal to a set of main field multiphase windings located on the rotor at 406. For example, the asynchronous rotating flux may be generated at the fourth set of multiphase windings 120.

[0072] The method 400 may include converting the asynchronous rotating flux into a host multiphase power signal at a set of main armature multiphase windings on the stator at 408. For example, the asynchronous rotating flux may be converted into a host multiphase power signal at the fifth set of multiphase windings 122.

[0073] An advantage of the method 400 is that an asynchronous rotating flux may be generated without a modulation circuit located on the rotor of a stand-alone variable speed variable frequency generator.Other benefits and advantages may exist.

[0074] Reference Figure 5, depicts an embodiment of a method 500 for externally modulated independent variable speed power generation. The method 500 may be used in situations where a pilot stage (eg, pilot stage 106) is unavailable for a variety of reasons.

[0075] The method 500 may include disconnecting the pilot stage from the generator control unit at 502. For example, the first switch circuit 138 may be used to disconnect the pilot stage 106 from the generator control unit.

[0076] The method 500 may include connecting the external power source to the generator control unit at 504. For example, the external power source 136 may be connected to the generator control unit 124 using the first switching circuit 138.

[0077] The method 500 may also include generating a high frequency modulated multiphase power signal using a power signal from an external power source at 506. For example, the generator control unit 124 may generate a high frequency modulated multiphase power signal using a multiphase power signal received from the external power source 136.

[0078] After method 500 has been completed, method 400 may be used to generate a multiphase power signal that is independent of the rotational frequency of rotor 102, which relies on power from an external power source to generate a high frequency modulated multiphase power signal. A benefit of method 500 is that external power source 136 may provide electrical power for generating a high frequency modulated multiphase power signal for use at master stage 110 of system 100, rather than using power from pilot stage 106. Other benefits and advantages may exist.

[0079] Reference Figure 6 , depicts an embodiment of a method 600 for operating an externally modulated stand-alone variable speed variable frequency generator system as a starter. The method 600 may include, at 602, connecting a motor starter drive to a set of main armature multi-phase windings before generating a high frequency modulated multi-phase power signal. For example, the switch circuit 144 may be controlled to connect the motor starter drive 140 to the fifth set of multi-phase windings 122.

[0080] The method 600 may further include, at 604 , disconnecting the plurality of switch circuits to prevent output at the multi-phase inverter. For example, the controller circuit 128 may control the pulse width modulation inverter 126 to disconnect the switch circuits 221 - 226 of the multi-phase inverter 220 .

[0081] The method 600 may also include sending a current pattern from a motor starter drive through a set of main armature multi-phase windings to generate a rotating flux pattern that causes the rotor to rotate, thereby starting the engine at 606. For example, the current pattern may be sent from the motor starter drive 140 to start the engine coupled to the rotor 102.

[0082] After method 600 is performed and the engine is started, methods 400 and / or 500 may be performed to generate a multiphase power signal that is independent of the rotational frequency of rotor 102. A benefit of method 600 may be that system 100 may operate as a starter for an engine coupled to rotor 102.

[0083] Furthermore, the present disclosure includes implementations according to the following clauses:

[0084] Clause 1. An independent speed-adjustable variable-frequency generator system (100), the independent speed-adjustable variable-frequency generator system comprising:

[0085] A rotor (102);

[0086] stator (104);

[0087] A lead generator stage (106) comprising a magnetic field source (112) located on the rotor (102) and a set of lead multi-phase windings (114) located on the stator (104);

[0088] A high frequency transformer stage (108) comprising a first set of high frequency transformer multiphase windings (116) located on the stator (104) and a second set of high frequency transformer multiphase windings (118) located on the rotor (102);

[0089] A main machine stage (110), comprising a set of main field multi-phase windings (120) located on the rotor (102) and a set of main armature multi-phase windings (122) located on the stator (104), wherein a second set of high-frequency transformer multi-phase windings (118) is directly coupled to the set of main field multi-phase windings (120); and

[0090] A generator control unit (124).

[0091] Clause 2. The independent variable speed generator system according to clause 1, wherein the generator control unit (124) comprises:

[0092] A multi-phase inverter (220) having a plurality of switching circuits (221-226); and

[0093] A controller circuit (128) is connected to an input terminal of each of the plurality of switch circuits.

[0094] Clause 3. An independent variable speed generator system according to clause 2, wherein, in the motor state, the controller circuit (128) is configured to disconnect each of the plurality of switch circuits (221-226) to prevent output at the multi-phase inverter (220).

[0095] Clause 4. An independent variable speed generator system according to Clause 2, wherein, in a power generation state, the controller circuit (128) is configured to open and close the plurality of switch circuits (221-226) in a manner to generate a high-frequency modulated multi-phase power signal (232), wherein the high-frequency modulated multi-phase power signal (232) includes a main magnetic field multi-phase power signal component (328) that can be used to drive the set of main magnetic field multi-phase windings (120) to generate a rotating magnetic flux that rotates relative to the rotor (102).

[0096] Clause 5. The independent speed-adjustable variable-frequency generator system according to Clause 4, further comprising:

[0097] A frequency sensor (130) is connected to the output of the multiphase inverter (220), wherein the controller circuit (128) is configured to adjust the frequency of the main magnetic field multiphase power signal component (328) based on the difference between the reference frequency (302) and the main magnetic field frequency (332) measured by the frequency sensor (130).

[0098] Clause 6. The independent speed-adjustable variable-frequency generator system according to Clause 4, further comprising:

[0099] A voltage sensor is connected to the output end of the set of main armature multiphase windings, wherein the controller circuit (128) is configured to adjust the voltage of the main field multiphase power signal component (328) based on the difference between the reference voltage (338) and the output voltage (340) measured by the voltage sensor (132).

[0100] Clause 7. The independent speed-adjustable variable-frequency generator system according to Clause 4, further comprising:

[0101] An encoder (134) is configured to detect a rotational frequency of a rotor (102), wherein a controller circuit (128) is configured to adjust a frequency of a main field multiphase power signal component (328) based on a difference between a reference frequency (302) and a rotor frequency (304) measured by the encoder (134).

[0102] Clause 8. The independent speed-adjustable variable-frequency generator system according to Clause 1, further comprising:

[0103] an external power source (136); and

[0104] A first switching circuit (138) is configured to open and close a connection between a lead generator stage (106) and a generator control unit (124) and to open and close a connection between an external power source (136) and the generator control unit (124).

[0105] Clause 9. The independent speed-adjustable variable-frequency generator system according to Clause 1, further comprising:

[0106] a motor starter driver (140); and

[0107] A second switching circuit (144) is configured to open and close the connection between the set of main armature multi-phase windings (122) and the power distribution bus (142) and to open and close the connection between the fourth set of multi-phase windings (122) and the motor starter drive (140).

[0108] Clause 10. A method for independent speed regulation and frequency conversion power generation, the method comprising the following steps:

[0109] Generating (402) a high frequency modulated multiphase power signal (232) at a generator control unit (124) located outside a rotor (102) of an independent variable speed generator (100), the high frequency modulated multiphase power signal (232) comprising a main field multiphase power signal component (328);

[0110] Transmitting (404) a high frequency multiphase power signal (232) from a stator (104) of an independent variable speed generator to a rotor (102) via a high frequency transformer stage;

[0111] Generating (406) an asynchronous rotating magnetic flux at a main field multiphase winding (120) by applying a main field multiphase power signal component (328) of a high frequency modulated multiphase power signal (232) to a set of main field multiphase windings (120) located on a rotor (102); and

[0112] Asynchronous rotating magnetic flux is converted (408) into a host multi-phase power signal at a set of main armature multi-phase windings (122) located on a stator (104).

[0113] Clause 11. The method according to clause 10, further comprising the following steps:

[0114] Connecting a set of pilot multi-phase windings (114) on the stator (104) to a multi-phase rectifier (210) of a generator control unit (124);

[0115] Generating a synchronously rotating magnetic flux at a magnetic field source (112) located on the rotor (102) that rotates synchronously with the rotor (102);

[0116] converting the synchronous rotating magnetic flux into a pilot multiphase power signal (230) using the set of pilot multiphase windings (114);

[0117] rectifying the pilot multiphase power signal (230) at the generator control unit (124) to generate a rectified power signal; and

[0118] The rectified power signal is used to generate a high frequency modulated multiphase power signal (232).

[0119] Clause 12. The method according to clause 10, further comprising the following steps:

[0120] connecting an external power source (136) to the generator control unit (124); and

[0121] A high frequency modulated multiphase power signal (232) is generated using a power signal from the external power source (136).

[0122] Clause 13. The method of clause 10, wherein the step of generating a high frequency modulated multiphase power signal (232) comprises:

[0123] A plurality of switch circuits (221-226) of a multiphase inverter (220) are opened and closed in a manner to generate a high frequency modulated multiphase power signal (232) at a controller circuit (128) of a generator control unit (124).

[0124] Clause 14. The method according to clause 13, further comprising the following steps:

[0125] connecting a motor starter drive (140) to the set of main armature multiphase windings (122) prior to generating a high frequency modulated multiphase power signal (232);

[0126] disconnecting the plurality of switch circuits (221-226) to prevent output at the multi-phase inverter (220); and

[0127] A current pattern is sent from a motor starter drive (140) through the set of main armature multiphase windings (122) to generate a rotating flux pattern that causes the rotor (102) to rotate, thereby causing the engine to start.

[0128] Clause 15. The method according to clause 14, further comprising the following steps:

[0129] After the engine is started, disconnecting the set of main armature multiphase windings (122) from the motor starter drive (140); and

[0130] The set of main armature multiphase windings (122) is connected to a power distribution bus (142).

[0131] Clause 16. The method according to clause 10, further comprising the following steps:

[0132] Receive a main magnetic field frequency signal (332);

[0133] receiving a reference frequency signal (302); and

[0134] The frequency of a main magnetic field multiphase power signal component (328) of a high frequency modulated multiphase power signal (232) is adjusted based on a difference between the main magnetic field frequency signal (332) and a reference frequency signal (302).

[0135] Clause 17. The method according to clause 10, further comprising the following steps:

[0136] Receiving an output voltage signal (340);

[0137] receiving a reference voltage signal (338); and

[0138] The voltage of a main magnetic field multiphase power signal component (328) of a high frequency modulated multiphase power signal (232) is adjusted based on a difference between a reference voltage (338) and an output voltage (340).

[0139] Clause 18. The method according to clause 10, further comprising the following steps:

[0140] Receiving a rotor frequency signal (304);

[0141] receiving a reference frequency signal (302); and

[0142] The frequency of a main field multiphase power signal component (328) of a high frequency modulated multiphase power signal (232) is adjusted based on a difference between a rotor frequency signal (304) and a reference frequency signal (302).

[0143] Clause 19. An independent speed-adjustable variable-frequency generator system (100), the independent speed-adjustable variable-frequency generator system comprising:

[0144] A rotor (102);

[0145] stator (104);

[0146] a high frequency transformer stage (106) comprising a first set of high frequency transformer multiphase windings (116) located on the stator (104) and a second set of high frequency transformer multiphase windings (118) located on the rotor (102); and

[0147] A main machine stage (110) includes a set of main field multi-phase windings (120) located on a rotor (102) and a set of main armature multi-phase windings (122) located on a stator (104), wherein a second set of high-frequency transformer multi-phase windings (118) is directly coupled to the set of main field multi-phase windings (120).

[0148] Clause 20. The independent speed-adjustable variable-frequency generator system according to Clause 19, further comprising:

[0149] A generator control unit (124) is configured to generate a high frequency modulated multiphase power signal (232), the high frequency modulated multiphase power signal (232) including a main field multiphase power signal component (328) that can be used to drive the set of main field multiphase windings (120) to generate an asynchronous rotating magnetic flux that rotates relative to the rotor (102).

[0150] Although various embodiments have been shown and described, the present disclosure is not limited thereto but is to be understood to include all modifications and variations that will be apparent to those skilled in the art.

Claims

1. An independent speed-regulating variable-frequency generator system (100), the independent speed-regulating variable-frequency generator system comprising: A rotor (102); stator (104); A lead generator stage (106) comprising a magnetic field source (112) located on the rotor (102) and a set of lead multi-phase windings (114) located on the stator (104); A high frequency transformer stage (108), the high frequency transformer stage (108) comprising a first set of high frequency transformer multi-phase windings (116) located on the stator (104) and a second set of high frequency transformer multi-phase windings (118) located on the rotor (102); A main engine stage (110), the main engine stage (110) comprising a group of main field multi-phase windings (120) located on the rotor (102) and a group of main armature multi-phase windings (122) located on the stator (104), wherein the second group of high-frequency transformer multi-phase windings (118) is directly connected to the group of main field multi-phase windings (120); A generator control unit (124), the generator control unit (124) comprising: a multi-phase inverter (220), the multi-phase inverter (220) having a plurality of switch circuits (221-226); and a controller circuit (128), the input end of each switch circuit in the plurality of switch circuits being connected to the controller circuit (128); an external power source (136); and A first switching circuit (138) is configured to open and close the connection between the pilot generator stage (106) and the generator control unit (124), and to open and close the connection between the external power source (136) and the generator control unit (124).

2. The independent speed-regulating variable-frequency generator system according to claim 1, wherein: In a motor state, the controller circuit (128) is configured to disconnect each of the plurality of switch circuits (221-226) to prevent output at the multi-phase inverter (220).

3. The independent speed-regulating variable-frequency generator system according to claim 1, wherein: In a power generation state, the controller circuit (128) is configured to open and close the plurality of switch circuits (221-226) in a manner to generate a high-frequency modulated multi-phase power signal (232), wherein the high-frequency modulated multi-phase power signal (232) includes a main magnetic field multi-phase power signal component (328) that can be used to drive the set of main magnetic field multi-phase windings (120) to generate a rotating magnetic flux that rotates relative to the rotor (102).

4. The independent speed-adjustable variable-frequency generator system according to claim 3, further comprising: A frequency sensor (130) is connected to the output of the multiphase inverter (220), wherein the controller circuit (128) is configured to adjust the frequency of the main magnetic field multiphase power signal component (328) based on a difference between a reference frequency (302) and a main magnetic field frequency (332) measured by the frequency sensor (130).

5. The independent speed-adjustable variable-frequency generator system according to claim 3, further comprising: A voltage sensor (132) is connected to the output end of the set of main armature multiphase windings, wherein the controller circuit (128) is configured to adjust the voltage of the main field multiphase power signal component (328) based on a difference between a reference voltage (338) and an output voltage (340) measured by the voltage sensor (132).

6. The independent speed-adjustable variable-frequency generator system according to claim 3, further comprising: An encoder (134) is configured to detect a rotational frequency of the rotor (102), wherein the controller circuit (128) is configured to adjust the frequency of the main field multiphase power signal component (328) based on a difference between a reference frequency (302) and a rotor frequency (304) measured by the encoder (134).

7. The independent speed-adjustable variable-frequency generator system according to claim 1, further comprising: Motor starter driver (140); as well as A second switch circuit (144) is configured to open and close the connection between the set of main armature multi-phase windings (122) and the power distribution bus (142), and to open and close the connection between the fourth set of multi-phase windings (122) and the motor starter drive (140).

8. A method for independent speed regulation and frequency conversion power generation, the method comprising the following steps: Generating (402) a high frequency modulated multiphase power signal (232) at a generator control unit (124) located outside a rotor (102) of an independent variable speed generator (100), the high frequency modulated multiphase power signal (232) comprising a main field multiphase power signal component (328); Transmitting (404) the high frequency modulated multi-phase power signal (232) from the stator (104) of the independent variable speed generator to the rotor (102) via a high frequency transformer stage; Generating (406) an asynchronous rotating magnetic flux at a set of main field multiphase windings (120) located on the rotor (102) by applying the main field multiphase power signal component (328) of the high frequency modulated multiphase power signal (232) to the main field multiphase windings (120); as well as converting (408) the asynchronous rotating magnetic flux into a host multi-phase power signal at a set of main armature multi-phase windings (122) located on the stator (104), The step of generating the high-frequency modulated multi-phase power signal (232) comprises: opening and closing a plurality of switch circuits (221-226) of a multiphase inverter (220) in a manner that generates the high frequency modulated multiphase power signal (232) at a controller circuit (128) of the generator control unit (124); connecting an external power source (136) to the generator control unit (124); and The high frequency modulated multiphase power signal (232) is generated using a power signal from the external power source (136).

9. The method according to claim 8, further comprising the steps of: Connecting a set of pilot multi-phase windings (114) on the stator (104) to a multi-phase rectifier (210) of the generator control unit (124); generating a synchronous rotating magnetic flux at a magnetic field source (112) located on the rotor (102) that rotates synchronously with the rotor (102); converting the synchronously rotating magnetic flux into a pilot multiphase power signal (230) using the set of pilot multiphase windings (114); rectifying the pilot multiphase power signal (230) at the generator control unit (124) to generate a rectified power signal; and The high frequency modulated multiphase power signal is generated using the rectified power signal (232).

10. The method according to claim 8, further comprising the steps of: Prior to generating the high frequency modulated multi-phase power signal (232), connecting a motor starter drive (140) to the set of main armature multi-phase windings (122); Disconnecting the plurality of switch circuits (221-226) to prevent output at the multi-phase inverter (220); as well as A current pattern is sent from the motor starter drive (140) through the set of main armature multiphase windings (122) to generate a rotating flux pattern that causes the rotor (102) to rotate, thereby causing the engine to start.

11. The method according to claim 10, further comprising the steps of: After the engine is started, disconnecting the set of main armature multiphase windings (122) from the motor starter drive (140); and The set of main armature multiphase windings (122) is connected to a power distribution bus (142).

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