Active harmonic filter and reactive power control system for naval vessel power systems

Abstract

The system includes a mains power supply (102) configured to supply power to at least one pulsed electrical load (114). The system also includes a propulsion converter (202) configured to drive a propulsion motor (204). The system further includes field-controlled induction electromachines (116, 224) coupled to at least one pulsed load. The field-controlled induction electromachines are configured to suppress one or more propulsion current harmonics generated by the propulsion converter and affecting at least one pulsed load.

Description

Technical Field

[0001] The present disclosure generally relates to power systems. More specifically, the present disclosure relates to an active harmonic filter and a reactive power control system for a power system of a naval vessel.

Background Art

[0002] The problem of power control in naval vessels is often associated with one or more problems, particularly prominent in the case of static filters. Conventional power filters for naval vessels use static AC capacitor banks of fixed capacity, which tend to depend on specific loads. When the load is variable, for example, in radar applications, the output capacity of the filtering current may be too small or too large and not optimal. Existing static capacitor banks have a relatively low energy density at a typical operating voltage of 480 volts. Similarly, switched capacitor banks tend to be less reliable because they generate extra harmonics on the input bus of the ship. As a result, the extra harmonics may cause a device to stop (such as a radar shutdown).

Summary of the Invention

[0003] The present disclosure relates to an active harmonic filter and a reactive power control system for a power system of a naval vessel.

[0004] In a first embodiment, the system includes a main power source configured to supply power to at least one pulsed load. The system also includes a propulsion converter configured to drive a propulsion motor. The system further includes a field-controlled induction electrical machine coupled to at least one pulsed load. The field-controlled induction electrical machine is configured to suppress one or more propulsion current harmonics generated by the propulsion converter and affecting at least one pulsed load.

[0005] In a second embodiment, the system includes an alternating current (AC) generator configured to supply active and reactive power to at least one pulse load via a main bus. The system also includes at least one hybrid energy storage module (HESM) configured to store at least a portion of the active and reactive power as energy for later use by at least one pulse load. The system further includes a high-speed asynchronous rotating machine (HSRM) configured to (i) supply reactive power to at least one HESM via a stator port, and (ii) suppress one or more harmonics generated by a first AC-AC frequency converter that affect at least one pulse load.

[0006] In a third embodiment, the filter device includes an inertial energy storage flywheel. The filter device also includes a field-controlled induction electromachine coupled to the inertial energy storage flywheel. The field-controlled induction electromachine includes a stator input winding and a plurality of stator output windings configured to connect to at least one pulse load. The field-controlled induction electromachine also includes a multiphase rotor circuit configured to receive a feedforward signal generated in response to one or more propulsion current harmonics affecting at least one pulse load. The feedforward signal is configured to control the field-controlled induction motor and the inertial energy storage flywheel to suppress one or more propulsion current harmonics.

[0007] Other technical features can be readily apparent to those skilled in the art from the following drawings, description, and claims.

[0008] For a more complete understanding of this disclosure, references to the following description are made herein, in conjunction with the attached drawings. [Brief explanation of the drawing]

[0009] [Figure 1] Examples of active harmonic filters and reactive power control systems provided in this disclosure are shown. [Figure 2] This disclosure shows another active harmonic filter and reactive power control system. [Figure 3A] Further details of an exemplary alternating current (AC)-to-alternating current (AC) converter coupled to a rotor circuit are provided in this disclosure. [Figure 3B] An exemplary winding diagram of a multiphase rotor circuit according to this disclosure is shown. [Figure 3C] Further details of an exemplary frequency and voltage converter coupled to a stator input winding, as described in this disclosure, are provided. [Figure 3D] The present disclosure shows exemplary winding diagrams for different stator windings. [Figure 3E] The present disclosure shows exemplary winding diagrams for different stator windings. [Figure 3F] The present disclosure shows exemplary winding diagrams for different stator windings. [Figure 4] Further active harmonic filters and reactive power control systems are described herein. [Figure 5] This disclosure also presents another active harmonic filter and reactive power control system. [Figure 6A] The present disclosure shows exemplary winding diagrams of various stator and rotor ports. [Figure 6B] The present disclosure shows exemplary winding diagrams of various stator and rotor ports. [Figure 6C] The present disclosure shows exemplary winding diagrams of various stator and rotor ports. [Figure 6D] The present disclosure shows exemplary winding diagrams of various stator and rotor ports. [Figure 7] This disclosure provides an exemplary exciter subsystem that can be used with active harmonic filters and reactive power control systems. [Modes for carrying out the invention]

[0010] Figures 1 to 7 described below, and the various embodiments used in this patent document to illustrate the principles of the disclosure, are illustrative only and should not be construed as limiting the scope of the disclosure. Those skilled in the art will understand that the principles of the disclosure may be implemented in any type of appropriately arranged device or system.

[0011] For the sake of brevity and clarity, some features and components are not explicitly shown in all figures, including those illustrated in conjunction with other figures. It will be understood that all features shown in the figures can be adopted in any of the embodiments described. The omission of features or components from certain figures is for the sake of brevity and clarity and does not mean that those features or components cannot be used in the embodiments described in relation to that figure. It will be understood that embodiments of this disclosure may include one, more, or all of the features described herein. Furthermore, embodiments of this disclosure may include additional or alternative features not described herein.

[0012] As mentioned above, power control issues in naval vessels are often associated with one or more problems, particularly concerning static filters. Conventional naval power filters use static AC capacitor banks with fixed capacitance, which tend to be load-dependent. When the load is variable, for example in radar applications, the output capacitance of the filtering current may be too small or too large, making it suboptimal. Existing electrostatic capacitor banks have relatively low energy density at a typical operating voltage of 480 volts. Similarly, switched capacitor banks tend to be unreliable because they generate extra harmonics in the ship's input bus. As a result, these extra harmonics can cause equipment failures (e.g., radar shutdown).

[0013] Low-frequency harmonics and stochastic electrical transients may be generated by the main propulsion electronic power converter driving either AC or DC propulsion motors. In the case of AC motors for propulsion in large vessels, the output frequency is typically a variable low frequency (e.g., approximately 5–40 Hz), and the system operates on a medium-frequency AC bus (e.g., approximately 60 Hz). Electrical repetitive harmonics from the propulsion converter, based on a fundamental frequency of approximately 2–30 Hz, are difficult to attenuate by capacitor banks due to the large size of the capacitor banks and concerns about undesirable resonance phenomena. As a result, many ship power systems use only a series multiphase inductive reactor as an interface filter from the propulsion converter to the main AC input bus. This method has limited ability to filter the spectrum of propulsion harmonics that would adversely affect other ship subsystems requiring undistorted input waveforms.

[0014] This disclosure provides embodiments of active harmonic filters and reactive power control systems for naval vessel power systems. In particular, embodiments of this disclosure address the problem of ship-borne propulsion harmonics that adversely affect radar identification capabilities or other operations. Embodiments of this disclosure use an all-electric ship propulsion drive employing a compact rotating machine with inertial energy storage to attenuate propulsion system harmonics. Embodiments of this disclosure enable ship AC power systems to be smaller and have higher power density. Furthermore, embodiments of this disclosure provide an uninterruptible power supply (UPS) function for radar power in the event of a main ship bus failure.

[0015] It will be understood that embodiments of this disclosure may include one, more, or all of the features described herein. Furthermore, embodiments of this disclosure may additionally or alternatively include other features not described herein. While embodiments of this disclosure are described in relation to naval vessels and early warning radar power systems, these embodiments are applicable to other suitable systems or applications.

[0016] Figure 1 shows an example of an active harmonic filter and a reactive power control system 100 according to the present disclosure. In some embodiments, system 100 may include or be part of a power system of a naval vessel. However, system 100 may include or be part of any other suitable system(s).

[0017] In a system such as that shown in Figure 1, special loads such as radars may require a separate power AC bus from the main ship power bus for various reasons. One reason is to isolate the radar load or other loads from the disturbances and electrical interference that may occur in the main ship power bus. Another reason is to isolate the main ship power bus from the pulsed and intermittent operating cycles that may be special loads, which may have an adverse effect on the main ship power system if not isolated.

[0018] As shown in FIG. 1, system 100 includes a ship turbine generator 102 that supplies power to system 100 via a main power bus 104. System 100 also includes a ship propulsion system 106, which may include a propulsion converter that drives an AC or DC propulsion motor. The ship propulsion system 106 may generate low-frequency harmonics and stochastic electrical transients. Connected to the ship propulsion system 106 is a series-connected filter reactor 108 that may include a set of polyphase detection windings wound together with the main power winding. The filter reactor 108 generates a feedforward low-frequency harmonic signal in response to one or more propulsion current harmonics generated by the propulsion system 106. The harmonic signal is supplied to an active filter 110, which is connected in series to an auxiliary system bus 112 (different from the parallel connection common in conventional systems) and supplies power to one or more sensitive loads 114. The one or more sensitive loads 114 may be one or a plurality of pulse loads such as radar, lasers, etc. The active filter 110 receives the harmonic signal from the filter reactor 108, processes the signal, and actively adjusts filtering parameters to minimize the impact of low-frequency harmonics generated by the ship propulsion system 106 on the load(s) 114.

[0019] System 100 also includes an inertial energy storage 116 coupled to the active filter 110. In some embodiments, the inertial energy storage 116 includes a flywheel. During operation of system 100, the kinetic energy of the inertial energy storage 116 may be converted into pulsed power and supplied to one or more loads 114. This enables substantially only steady-state energy to be received from the main bus 104.

[0020] The inertial energy storage 116 connected to the active filter 110 may provide an adjustable reactive power source with energy storage to control the system power of the main power bus 104 and absorb or dissipate one or more propulsive harmonics. In addition, the active filter 110 and the inertial energy storage 116 may provide energy storage for an uninterruptible power supply (UPS) function that enables minutes of continuous or critical power use by a load 114 when the main power bus 104 is temporarily unavailable.

[0021] As described above, system 100 electrically isolates the highly sensitive load(s) 114 from the main ship propulsion harmonics, which are primarily low-frequency harmonics. System 100 provides more effective filtering and harmonic / reactive power control than conventional systems where filters are not connected in series. Additional details and advantages will be described in conjunction with other embodiments described below.

[0022] Figure 2 shows another active harmonic filter and reactive power control system 200 according to the present disclosure. In some embodiments, system 200 may include or be part of a power system for a naval vessel. However, system 200 may include or be part of any other suitable system(s). As described below, system 200 includes a four-port double-feed induction electromachine, which has an inertia storage flywheel and a harmonic suppression function for harmonic currents of a propulsion motor converter using a feedforward control loop and an actively modulated mechanical rotor excitation circuit. System 200 includes several components that are identical or similar to the corresponding components in system 100 of Figure 1.

[0023] As shown in Figure 2, the system 200 includes a main propulsion converter 202 that drives an AC or DC propulsion motor 204. The main propulsion converter 202 can generate low-frequency harmonics and stochastic electrical transients. In the case of an AC motor 204 for propulsion in a large vessel, the output frequency Fp is typically a variable low frequency (e.g., about 5 to 40 Hz), and the system 200 operates on a medium-frequency AC bus 206 (e.g., about 60 Hz). One or more electrical repetitive harmonics from the main propulsion converter 202 based on a fundamental frequency of about 2 to 30 Hz are difficult to attenuate by a capacitor bank due to the large size of the capacitor bank and concerns about undesirable resonance phenomena.

[0024] System 200 also includes an input propulsion series-connected filter reactor 208, which includes a set of multiphase sensing windings 210 wound together with the main power winding. The multiphase sensing windings 210 generate a low-level signal Vh in response to one or more propulsion current harmonics. The signal Vh is sent to a low-pass multiphase filter 212 to remove high-frequency switching transients from the main propulsion converter 202. Each of the individual phase signals is sent to a phase-inverting operational amplifier 214, such as a wideband 180° inverter, to generate an output signal Ip, which includes a set of multiphase feedforward signals. The output signal Ip includes a harmonic spectrum of low-frequency "fh" as well as a single individual frequency. For example, if the main AC propulsion frequency is 5 Hz, the set of the 5th, 7th, 11th, and 13th harmonics, which are the usual 6 pulse harmonics, may generate major undesirable harmonic frequencies of 25 Hz, 30 Hz, 55 Hz, and 65 Hz. If the main propulsion converter 202 is a 12-pulse converter, the 11th, 13th, 23rd, and 25th harmonics become more important. This group of multiphase feedforward signals forming the output signal Ip is fed to a set of variable-gain multiphase power amplifiers 216, which may have a forward gain (e.g., 100:1) for amplifying the feedforward signals.

[0025] The output signals (identified as "Io") from the set of power amplifiers 216 are supplied on the high-impedance or primary side to a set of polyphase harmonic-canceling injection transformers 218-220 ("T1", "T2", "T3"). The transformers 218-220 are coupled to the polyphase rotor circuit 222 of the double-feed wound rotor induction electromachine 224, which will be described in more detail below. The secondary or low-impedance sides of the transformers 218-220 are connected in series to the rotor excitation circuit, which includes a control current source variable frequency AC-AC converter 226 and an input step-down transformer 228 from the main AC bus 206 (as indicated by the current "Ir").

[0026] Figure 3A provides further details of an exemplary AC-AC converter 226 coupled to the rotor circuit 222 according to this disclosure. As shown in Figure 3A, the AC-AC converter 226 uses an internal power semiconductor switching circuit for a current-source type AC-DC-AC rectifier / inverter, together with injection transformers 218-220 in the rotor excitation circuit feed. In Figure 3A, the AC-AC converter 226 includes 12 thyristor devices. However, this is merely an example, and other embodiments may include IGBT switching devices, IGCT switching devices, high-power MOSFET switching devices, or any other suitable switching devices.

[0027] The AC-AC converter 226 and injection transformers 218-220 with feedforward signals are combined to excite the polyphase rotor circuit 222 of the induction electromachine 224. The output frequency "fr" of the AC-AC converter 226 is a low "slip" frequency (e.g., about 2-6 Hz) and is above the lower limit of the spectrum of the electrical frequency range "fh" in the feedforward signal path. That is, the frequency fr may be less than or equal to about 1 / 10 of the lowest frequency of the target propulsion harmonic at any given time. As a result, the polyphase rotor circuit 222 receives a base excitation frequency fr modulated by the harmonic cancellation frequency fh at a substantial power level with an equivalent amplitude to the main excitation level from the AC-AC converter 226.

[0028] Figure 3B shows an exemplary winding diagram of a multiphase rotor circuit 222 according to the present disclosure. As shown in Figure 3B, the multiphase rotor circuit 222 is configured as a Y-connection circuit. The induction electromechanism 224 functions as a rotational current amplifier from the rotor winding to the stator winding, having a high coupling coefficient, such as a coupling coefficient of over 95%.

[0029] The induction electromachine 224 has three stator windings, including a stator input winding 230 ("S1") and two stator output windings 231 and 232 ("S2" and "S3"). Each winding has a separate function. The stator input winding 230 is a multiphase Y-connected motor winding powered by an AC-AC frequency and voltage converter 234 using an internal power semiconductor switching circuit. Figure 3C shows further details of an exemplary frequency and voltage converter 234 coupled to the stator input winding 230 according to this disclosure. As shown in Figure 3C, the frequency and voltage converter 234 includes an AC link type internal circuit that performs AC-AC frequency conversion from frequency f1 to frequency f3, which is input to the stator input winding 230. In Figure 3C, the frequency and voltage converter 234 includes twelve thyristor devices. However, this is merely one example, and other embodiments may include IGBT switching devices, IGCT switching devices, high-power MOSFET switching devices, or any other suitable switching device.

[0030] The induction electromachine 224 also includes an inertial energy storage flywheel 236 coupled to the rotor circuit 222. The inertial energy storage flywheel 236 operates to store energy that can be supplied to the load(s) on the system 200. A speed and torque controller (STC) 238 coupled to the frequency and voltage converter 234 sets the frequency f3 and magnetic flux level supplied to the induction electromachine 224 and maintains the inertial energy storage flywheel 236 at maximum speed and kinetic energy levels after load discharge events. The STC 238 also sends control signals to the AC-AC converter 226 so that the base excitation frequency fr is adjusted with the frequency f3 of the stator input winding 230 to determine the variable machine shaft speed and the kinetic energy level of the flywheel. In some embodiments, the output frequency f3 is a medium to high frequency (e.g., about 100-400 Hz) to allow for high electromachine shaft speeds for the inertial storage function. To maximize overall efficiency, the rotor base frequency fr may be maintained in the range of approximately 1% to 1.5% of the frequency f3, i.e., approximately 1 to 6 Hz. Figure 3D shows an exemplary winding diagram of the stator input winding 230. As shown in Figure 3D, the stator input winding 230 is configured as a Y-connection circuit.

[0031] The stator output windings 231 and 232 of the induction electromachine 224 are both polyphase and isolated from each other. The stator output winding 231 includes a main output port, which supplies power to a sensing current transformer CT and a vacuum breaker VB, and sends the main output power at voltage V2 and frequency f2 to a polyphase current regulator 240 and an AC-DC full-wave bridge rectifier 242. The polyphase current regulator 240 is controlled by one output function of the STC 238. The power output of the bridge rectifier 242 is capacitively filtered at potential Vd. The power output is sent to a pulsed or steady-state DC load 244. Figure 3E shows an exemplary winding diagram of the stator input winding 231. As shown in Figure 3E, the stator output windings 231 are delta connected.

[0032] The stator output winding 232 includes an auxiliary output port that connects to a multiphase damper circuit 246. As shown in Figure 2, the multiphase damper circuit 246 may be a delta-connected resistive-capacitive network and serves to dampen shaft velocity vibrations or enable dynamic braking of the inertial energy storage flywheel 236 when the AC main bus 206 cannot accept mechanically generated regenerative energy to decelerate the inertial energy storage flywheel 236 or cannot absorb any resulting electromechanical vibrations. A vacuum breaker VB is shown for each phase, and when shaft vibration or an overspeed condition is detected, the operation of the STC 238 connects the multiphase damper circuit 246 to the stator output winding 232. Figure 3F shows an exemplary winding diagram of the stator input winding 232. As shown in Figure 3F, the stator output winding 232 is delta-connected.

[0033] System 200 also includes a series of current transformers CTs located on the stator output winding 231, which supply a feedback signal "If" to a low-level current-voltage converter 248 or operational amplifier having an output voltage Vf. A set of bias signals output from the current-voltage converter 248 is sent to the power amplifier 216, phase by phase. Each bias signal of voltage Vf provides the power amplifier 216 with a phase angle input to optimize the phase angle of the injected signal Io, enabling maximum cancellation of propulsive harmonics at frequency fh.

[0034] Table 1 shows typical design values ​​for a machine with a rating of 4,000 [kVA], a maximum speed of 15,000 RPM, and an energy storage capacity of 75 [MJ]. Of course, these design values ​​are merely examples, and other values ​​are possible and within the scope of this disclosure. Table 1: Typical design values [Table 1]

[0035] Figure 4 shows yet another active harmonic filter and reactive power control system 400 according to the present disclosure. In some embodiments, system 400 may include or be part of a naval vessel power system. However, system 400 may include or be part of any other suitable system(s). System 400 may include multiple components identical or similar to the corresponding components in system 100 in Figure 1 or system 200 in Figure 2. As shown in Figure 4, system 400 includes a main power (ship) generator 402 that is powered via a main power bus 404. The apparent power from the main power bus 404 includes active power (P1) and reactive power (Q1), at least a portion of which is supplied to a dedicated combat system bus 406 or a group of auxiliary system buses. The active and reactive power are supplied to an AC-AC frequency converter 408 and a group of hybrid energy storage modules (HESMs) 410.

[0036] The AC-AC frequency converter 408 converts the frequency f1 of the combat system bus to a higher frequency f3 of multiphase power, supplying power to the HESM 410 via a variable frequency AC bus. The HESM 410 operates as a power and storage energy source for a number of corresponding pulse loads 412 (such as high-power lasers, radars, etc.), which are typically DC loads and may have stochastic or pulsed operating cycles. Each HESM 410 includes an inertial energy storage motor generator set with an electrical output specifically configured for the special load 412. Each HESM 410 is also coupled to an inertial energy storage flywheel 414, each having inertial energy storage capacities E1 and E2 tuned to the specific operating cycle of the corresponding load 412. Figure 4 shows two HESM 410s corresponding to two loads 412, but this is for illustrative purposes only. Other embodiments may include one or more HESM 410s and loads 412. System 400 offers superior electromagnetic conductivity emission characteristics compared to conventional systems and provides complete galvanic isolation from pulse effectors (e.g., lasers) and pulse sensors (e.g., radar).

[0037] Active power P1 for supplying power to the combat system bus 406 is supplied from the main power bus 404 via a multiphase AC series reactor 416, which removes high-frequency harmonics generated on the main power bus 404. The reactor 416 allows low-frequency power (primarily active power) to pass through without attenuation. Reactive power Q1 for supplying power to the combat system bus 406 is supplied using two main elements: (i) an AC-AC frequency converter 418 (capable of multiphase input and multiphase output), and (ii) a high-speed asynchronous rotary machine (HSRM) 420. The HSRM 420 includes an input port / stator winding S5 from the AC-AC frequency converter 418 and an isolated output port / stator winding S6. In some embodiments, the HSRM 420 can be a wound-rotor type double-feed inductive generator (DFIG). The HSRM 420 also includes an excitation port R3 for receiving an excitation signal from an exciter 422. In some embodiments, the excitation port R3 is a multiphase AC input for generating the rotating magnetic field of the HSRM and can play a role in controlling the precise amount and voltage level of the reactive power output.

[0038] The HSRM420 operates as an asynchronous capacitor (ASC) that supplies adjustable reactive power Q1 from the main power bus 404 at stator port S6 without requiring inertial energy storage. The reactive power Q1 is in orthogonal phase with the active power P1 of the combat system bus 406. By adjusting the speed of the HSRM420 and consequently the flux level of the HSRM420, the combat system bus 406 obtains a constant level of reactive power necessary for rectifying the switching devices in the converter 408, and can also accommodate the inductive drop (using reactive power) of the power transmission cables along the combat system bus 406. Furthermore, the HSRM420 functions as an active filter at port S6 against harmonics generated by the AC-AC frequency converter 418, such as the 5th, 7th, 11th, and 13th harmonics of the line frequencies used in the combat system bus 406. This configuration minimizes the need for a large electrostatic capacitor bank in combat system bus 406, as high-voltage electrostatic capacitor banks typically use flammable insulating fluids, which are undesirable for naval vessels.

[0039] In some embodiments, the HESM410s have the same number of stator poles and the same upper limit on the speed of the corresponding flywheel 414. Because shaft speeds may deviate from each other due to differences in load or operating cycle, fine speed control of each HESM410 can be adjusted by the final slip frequency output of each mechanical exciter R1 and R2. In other embodiments, each HESM410 may have an independent frequency converter 408 to operate with significantly different loads.

[0040] The HESM410 has stator ports S1 and S2, which include AC output ports S3 and S4, respectively. Each output port S3 and S4 is connected to an AC-DC converter 424 having different frequency outputs, which rectifies the AC power and sends this power as DC to the respective loads 412. The HESM410 is excited by individual AC variable frequency exciters 426, which supply power to each HESM410 via rotor ports R1 and R2 and may be connected to slip ring conductor assemblies and electric brushes for power and transmission. The exciters 426 may be fast-response AC power supplies capable of responding to stochastic or transient power loads, such as those having a bandwidth of 20 kHz.

[0041] To cope with a surge in load demand, kinetic energy is extracted from the inertial energy storage flywheel 414, and as the speed of the HESM 410 decreases, each exciter 426 monitors the machine's shaft speed and, as a result, increases the excitation rotor frequency inversely proportional to the shaft speed to maintain the output frequency at ports S3 and S4 at a constant value. This helps support efficient AC-DC rectification. Since there are no transients or harmonics from the main power bus 404 at ports S3 and S4, the rectification to the DC power supply is stable and of high quality.

[0042] In some embodiments, the load may have significantly different pulse operating cycles or be a stochastic load. In such cases, surge energy is drawn from the inertial energy storage flywheel 414, and the effective load to the AC-AC frequency converter 408 (and thus the combat system bus 406) is buffered, resulting in a nearly steady-state power draw. Thus, the power P1 is buffered without load transients. Further filtering is performed by the multiphase AC series reactor 416.

[0043] The combination of AC-AC frequency converters 408 and 418 and inertia storage provided by the flywheel 414 prevents the main power bus 404 from being affected by pulsed or shock-like effects from effector or sensor loads. Furthermore, the HSRM420, operating as an ASC machine, provides a controllable negative or positive VAR to filter out the main AC propulsion harmonics at any speed. Here, the harmonic energy may be absorbed by the rotor and stator windings of the HSRM420.

[0044] Figure 5 shows yet another active harmonic filter and reactive power control system 500 according to the present disclosure. In some embodiments, system 500 may include or be part of a power system for a naval vessel. However, system 500 may include or be part of any other suitable system(s). System 500 includes several components identical or similar to the corresponding components in system 400 of Figure 4. However, in system 500, a common exciter AC bus 502 supplies power from HSRM420 to all rotating machinery sets via a secondary output winding / port S7.

[0045] As shown in Figure 5, the exciters 422 and 426 that supply power to the rotor ports R1, R2, and R3 of the HESM410 and HSRM420 are powered from the output winding / port S7 of the HSRM420. The output winding / port S7 may be a low-voltage, low-power winding, while the main output port S6 may be a high-voltage, high-power winding. This arrangement is advantageous or necessary because the power supply for the exciters 422 and 426 must not be subject to electrical disturbances from the main power bus 404 or the combat system bus 406. The output frequency f2 from the AC-AC frequency converter 418 may be higher than the main frequency (e.g., about 120 Hz) and powers the winding S5 of the HSRM420, which is a 4-pole winding that enables a shaft speed (e.g., about 3550 RPM). The generator winding S6 may be a two-pole stator winding, and its output frequency may be approximately 60 Hz, allowing reactive power from Q1 to be injected at the main frequency f1.

[0046] The excitation frequency f4 of the output winding / port S7 may be approximately 360 Hz. This may be a single-phase output using a magnetic frequency tripling configuration obtained from an input frequency of 120 Hz. Any suitable frequency tripling circuit may be used. The output winding / port S7 may be an open delta winding, and the primary winding may be a stator connected in a Y configuration as shown in winding S5. The power generated by the output winding / port S7 is distributed to multiple excitation power loads and rectified and invertered to become the rotor excitation power of the machine. Thus, the HSRM420 has three operating electrical frequencies in the stator winding of the motor-generator composite set.

[0047] In some embodiments, stators S5 and S7 interact with a squirrel-cage or solid-type induction rotor. In other embodiments, the main output winding or invalid output winding S6 interacts only with a multiphase winding rotor, but that rotor is mounted on the same shaft as the squirrel-cage rotor. Figures 6A to 6D show exemplary winding layouts for ports S5, S6, S7, and R3, respectively, according to this disclosure.

[0048] Figure 7 shows an exemplary exciter subsystem 700 that can be used with an active harmonic filter and reactive power control system according to the present disclosure. In some embodiments, the exciter subsystem 700 can be part of the power control system 400 of Figure 4 or the power control system 500 of Figure 5. In particular, the exciter subsystem 700 can be used in the rotor supply circuits of all electromechanical components in the power control systems 400 and 500. However, the exciter subsystem 700 may also be part of any other suitable system.

[0049] As shown in Figure 7, the exciter subsystem 700 operates as an exciter power supply, generating variable frequency variable voltage AC power to ports R1, R2, and R3 of the rotor winding 702. An intermediate supercapacitor energy storage bank 704, installed in the DC link, provides filtering and stabilization of the DC power before the final frequency conversion by devices 1SCR1 to 1SCR6. The input frequency to the exciter subsystem 700 is a medium frequency (e.g., about 180 Hz or 360 Hz), and the output "slip" frequency to the mechanical rotor is a variable low frequency (e.g., about 5 to 30 Hz).

[0050] Figures 1 to 7 show examples and related details of active harmonic filtering and reactive power control systems, although various modifications can be made to Figures 1 to 7. For example, various components in systems 100, 200, 400, and 500 may be combined, further subdivided, duplicated, rearranged, or omitted, and additional components may be added according to specific needs. Also, Figures 1 to 7 show examples of operating environments in which active harmonic filtering and reactive power control can be performed, but this functionality can be used in any other suitable system.

[0051] In some embodiments, the various functions described in this patent document are implemented or supported by computer programs formed from computer-readable program code and embodied in computer-readable media. The term "computer-readable program code" includes any type of computer code, including source code, object code, and executable code. The term "computer-readable media" includes any type of media that a computer can access, such as read-only memory (ROM), random-access memory (RAM), hard disk drives (HDDs), compact discs (CDs), digital video discs (DVDs), or any other type of memory.

[0052] It may be beneficial to provide definitions of certain words and phrases used throughout this patent document. The terms “Application” and “Program” mean one or more computer programs, software components, instruction sets, procedures, functions, objects, classes, instances, associated data, or parts thereof, as adapted for implementation in appropriate computer code (including source code, object code, or executable code). The term “communicate” and its derivatives encompass both direct and indirect communication. The terms “include” and “comprise” and their derivatives mean to include without limitation. The term “or” is inclusive and means and / or. The phrase “associated with” and its derivatives may mean to include, contain, connect with, include, connect to or with, combine with or communicate with, cooperate with, sandwich, juxtapose, be close to, be bound to or with, have, possess the characteristics of, have a relationship with or with. When the phrase "at least one of" is used in a list of items, it means that one or more different combinations of the listed items may be used, and that only one item from the list may be required. For example, "at least one of: A, B, and C" includes any of the following combinations: A, B, C, A and B, A and C, B and C, and A, B and C.

[0053] The descriptions in this disclosure should not be interpreted as implying that any particular element, step, or function must be an essential or important element of the claims. The scope of the subject matter is defined solely by the permitted claims. Furthermore, no claim shall exercise 35 U.S.C. § 112(f) with respect to any of the appended claims or elements of the claims unless the exact phrases “means for” or “step for” are explicitly used in a particular claim followed by a participial phrase specifying a function. The use of terms such as “mechanism,” “module,” “device,” “unit,” “component,” “element,” “member,” “apparatus,” “machine,” “system,” “processor,” or “controller” in a claim is understood to and intended to refer to (but not limited to) a structure known to those skilled in the art, which may be further modified or enhanced by the features of the claim itself, and not intended to exercise 35 U.S.C. § 112(f).

[0054] While this disclosure has described specific embodiments and generally related methods, alternative and substitute forms of these embodiments and methods will be apparent to those skilled in the art. Therefore, the above description of exemplary embodiments does not define or limit this disclosure. Other modifications, substitutions, and alternatives are possible without departing from the spirit and scope of this disclosure, as defined by the following claims.

Claims

1. A system, and said system is A mains power supply configured to supply power to at least one pulse load, A propulsion converter configured to drive a propulsion motor, A field-controlled induction electromachine coupled to the at least one pulse load, the field-controlled induction electromachine is configured to suppress one or more propulsion current harmonics generated by the propulsion converter and affecting the at least one pulse load, system.

2. The system according to claim 1, further comprising a filter reactor coupled to the propulsion converter, the filter reactor being configured to (i) generate a feedforward signal in response to one or more propulsion current harmonics, and (ii) output the feedforward signal for use in the field-controlled induction electromachine.

3. The system according to claim 2, wherein the feedforward signal includes a plurality of signals corresponding to different harmonic frequencies of the one or more propulsion current harmonics.

4. The system according to claim 2, further comprising one or more power amplifiers configured to amplify the feedforward signal before it is input to the excitation system of the field-controlled induction electromachine.

5. The system according to claim 2, wherein the field-controlled induction electromachine includes a multiphase rotor circuit configured to receive an excitation signal in response to the feedforward signal generated by the filter reactor.

6. The system according to claim 5, further comprising an AC-to-AC converter and a plurality of injection transformers, the plurality of injection transformers configured to generate the excitation signal supplied to the polyphase rotor circuit.

7. The system according to claim 5, further comprising an inertial energy storage flywheel coupled to the multiphase rotor circuit and configured to store and supply energy used by the at least one pulse load.

8. The system according to claim 7, further comprising a speed and torque controller (STC) configured to control the frequency and magnetic flux levels supplied to the field-controlled induction electromachine in order to maintain the inertial energy storage flywheel at a predetermined speed and kinetic energy level after one or more load discharge events associated with the at least one pulsed load.

9. The system according to claim 1, wherein the field-controlled induction electromachine further includes a stator input winding and a plurality of stator output windings.

10. A system, and said system is An alternating current (AC) generator configured to supply active and reactive power to at least one pulse load via a main bus, At least one hybrid energy storage module (HESM), the at least one HESM configured to store at least a portion of the active power and the reactive power as energy for later use by the at least one pulse load, (i) supplying the reactive power to the at least one HESM via a stator port, and (ii) a high-speed asynchronous rotary machine (HSRM) configured to suppress one or more harmonics generated by a first AC-AC frequency converter that affect the at least one pulse load, system.

11. The system according to claim 10, wherein the HSRM is configured to operate as an asynchronous capacitor (ASC), and the asynchronous capacitor (ASC) supplies adjustable reactive power to at least one pulse load at one or more output ports to supply reactive power.

12. The system according to claim 10, further comprising a second AC-AC frequency converter configured to adjust the frequencies of the active power and the reactive power before the active power and the reactive power are input to the at least one HESM.

13. The at least one pulse load includes a plurality of pulse loads, The system according to claim 10, wherein the at least one HESM comprises a plurality of HESMs, each of which is coupled to one of the plurality of pulse loads and configured to store energy and supply the energy to one of the plurality of pulse loads.

14. The system according to claim 10, wherein the HSRM and the at least one HESM are each coupled to a corresponding exciter, the corresponding exciter being configured to supply an excitation current to the rotor winding of the HSRM or the HESM.

15. The system according to claim 14, wherein the exciter is coupled to a common exciter bus.

16. The system according to claim 14, wherein each exciter is configured to generate a variable frequency variable voltage AC power, which is input to a plurality of ports of the corresponding rotor winding to control the magnetic flux level of the HSRM or the HESM.

17. A filter device, said filter device, An inertial energy storage flywheel, The field-controlled induction electromachine is coupled to the inertial energy storage flywheel, and the field-controlled induction electromachine is Stator input winding and, Multiple stator output windings configured to connect to at least one pulse load, The circuit includes a multiphase rotor circuit configured to receive a feedforward signal generated in response to one or more propulsion current harmonics affecting the at least one pulse load, The feedforward signal is configured to control the field-controlled induction electromachine and the inertial energy storage flywheel to suppress one or more propulsion current harmonics. Filter device.

18. The filter device according to claim 17, wherein the inertial energy storage flywheel is coupled to the multiphase rotor circuit and configured to store and supply energy used by the at least one pulse load.

19. The filter device according to claim 17, wherein the feedforward signal includes a plurality of signals corresponding to different harmonic frequencies of the one or more propulsion current harmonics.

20. The filter device according to claim 17, further comprising a speed and torque controller (STC) configured to control the frequency and magnetic flux levels supplied to the field-controlled induction electromachine in order to maintain the inertial energy storage flywheel at a predetermined speed and kinetic energy level after one or more load discharge events associated with the at least one pulsed load.

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