Abstract:
An auto-regulated motion power system apparatus that may be used to generate usable electricity from disparate energy sources includes a combination of a variable frequency alternator driven by a primary mover and coupled to a load. An energy control module includes a closed-loop feedback system coupled to a pulse width modulation controller and a switch mode rectifier. The alternator has a modulated control signal input having the ability to vary in frequency and voltage with an output having a controlled voltage and varying frequency. The switch mode rectifier accepts variable AC voltages from the alternator and outputs a constant predetermined DC voltage both to one side of the windings of the alternator and to a first side of a high frequency switch. An output on the pulse width modulation generator is connected to a switch control so that when the switch is closed, current flows through the windings of the alternator and when the switch is open, no current flows through the windings. This modulation of current flow (or lack thereof) regulates the magnetic field strength inside the alternator to produce a stable voltage over a wide range of RPMs.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims priority based on U.S. Provisional Patent Application Ser. No. 61/287,666 filed Dec. 17, 2009 and titled “Auto-regulated Motion Power System,” the disclosure of which is incorporated herein by this reference. 
    
    
     BACKGROUND 
     This invention relates to an apparatus for converting rotational energy into electrical energy, and a system of using the apparatus to recover energy as useful power that would otherwise be lost. 
     Providing portable AC power is an expanding field. In particular, many automobiles are now being equipped with inverters to provide 110V AC power to outlets in the vehicle. However, providing high amperage power can be difficult and inefficient. Furthermore, providing such power often requires significant revving of the engine, meaning a person has to be sitting at the wheel to press on the gas pedal or a high idle controller must be installed in the vehicle, increasing costs. The standard “stock” alternator is not sufficient to provide higher amperages than the design of the automobile requires for engine ignition, engine control computer, radio, and standard signal and lighting requirements. 
     Previously, it was often necessary to utilize a generator configured to produce constant-frequency AC output at a specific higher engine rotational rate (fixed RPM), for example through reduction gears (going from 3600 RPM, for example, to 1800 RPM for a 60 Hz output). Such systems are normally configured to maintain a constant rotational rate through a governor or other rotational regulator. Use of a variable rotational speed was often impractical. 
     Many water systems have very high pressure at the source, which pressure must be reduced prior to sending the water into the general municipal water supply. Reducing this pressure typically involves pressure regulator valves, which unfortunately waste all of the potential energy available in the high-pressure water. Windmills may also be used to generate rotational potential energy, and much effort has gone into exploiting that energy source. Thus, an apparatus that could convert a variety of sources of potential energy into usable electricity would be useful. 
     SUMMARY 
     This application discloses an auto-regulated motion power system (“AMPS”) apparatus that may be used to generate usable electricity from existing energy sources. In particular, the AMPS apparatus includes a combination alternator and energy control module that may be used to convert sources of potential or rotary energy to, for example, 115V AC power. The apparatus has potential application in the production of energy where the prime mover (source of energy) is not constrained to a specific RPM to deliver sufficient energy to an alternator to maintain a given load. 
     The present apparatus includes a three-phase variable frequency alternator having an input that is attachable to a prime mover (a source of power), coupled to an inverter or frequency controller and to an energy control module (“ECM”). The alternator may alternatively be connected to a frequency independent load, which would eliminate the need for a frequency controller. The ECM includes a multi-phase closed-loop feedback system coupled to a pulse width modulation controller and an inverter or switch mode rectifier (“SMR”) to convert variable frequency energy to useful, clean, constant, AC power. 
     The alternator has a modulated control signal input having the ability to vary in frequency and voltage with an output having a set voltage and varying frequency. The output of the alternator also connects to a feedback loop and control system having a field driver incorporated into the ECM. The alternator has at least one set of windings that permit application of a variable magnetic field inside the alternator. 
     The energy control module or ECM typically has a three-phase switch mode rectifier (“SMR”) that accepts variable AC voltages (for example, voltages from 120 to 600 volts) from the alternator and outputs a constant predetermined DC voltage both to one side of the field winding of the alternator and to one side of a high frequency switch. An output on the pulse width modulation generator is connected to the switch control so that when the switch is closed current flows through the windings of the alternator and when the switch is open no current flows through the windings. This current flow (or lack thereof) will increase and decrease the magnetic field strength inside the alternator field winding, and may be regulated sufficiently at high speeds so as to maintain a predetermined field strength inside the alternator, thereby causing the alternator to produce a predetermined stable voltage over a wide range of RPMs of the prime mover. The alternator also has the ability to accept a low-voltage, low current source for initial activation (or excitation) of the alternator when “priming” of the alternator is required. 
     The AMPS apparatus may be employed in numerous fields where there exists an energy source capable of turning the shaft of the alternator. Exemplary fields of application include (1) mobile power where the primary mover is an internal combustion engine; (2) in combination with turbines to replace PRVs (pressure regulator valves) in pressurized water systems or moving water with varying flows and elevation changes, and (3) wind driven applications. An energy source capable of turning the shaft of the alternator with adequate torque requirements will allow the apparatus to produce output power. 
     One advantage of the present apparatus is its ability to produce relatively constant output power with a variable frequency energy input source. This constant output power allows for the production of power from green energy sources, such as wind turbines or turbines in a water flow. However, in the case of a combustion engine, where maximum optimal efficient power is typically required at lower rotational speeds or even the idle speed of the engine, the constant output also results in reduced carbon emissions because the power may be generated with reduced fuel consumption compared to devices that require the engine to operate at higher speeds. 
     The AMPS apparatus may be used to generate clean, reliable power from a prime mover while providing increased efficiency by optimizing efficiencies of the prime mover for power requirements. It also allows a wider range of prime mover possibilities. Unlike traditional generators that require a constant RPM, the AMPS apparatus delivers power over a wide range of rotational inputs (typically, 1000 RPM to 18,000 RPM). When the AMPS apparatus is implemented with combustion engines, throttle speed is typically no longer a major concern. A vehicle, boat, etc. can fulfill predetermined load requirements when the engine is at idle or full throttle or most anywhere in between, whenever the engine is running and can provide sufficient torque for the power application. The system becomes an efficient, RPM independent, power generator. 
     In a mobile application, the AMPS apparatus can be utilized to power intersection traffic lighting during power outages, emergency communications, emergency lighting, utility and construction vehicles, military or defense operations, marine applications, and even medical equipment. It can also power equipment in remote areas without the need for separate fuel systems, heavy trailers or taking up significant amounts of valuable space in vehicles. Due to its control and regulation design, the AMPS apparatus can also regulate torque while producing power. In an in-line hydro application this feature allows water pressure and flow control dynamically while converting normally wasted energy to power. The apparatus can also be used to replace pressure regulator valves in in-line hydro systems, as well as in numerous other applications. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Other features and advantages of the present invention will be apparent from reference to the following Detailed Description taken in conjunction with the accompanying Drawings, in which: 
         FIG. 1  depicts a block diagram of the apparatus; 
         FIG. 2  depicts a side view of an alternator constructed for use in the apparatus of  FIG. 1 ; 
         FIG. 3  depicts a side view the alternator of  FIG. 2  showing certain interior components of the alternator in dashed lines; 
         FIG. 4  depicts a cross-sectional view of the alternator of  FIG. 2  taken along the line  4 - 4  of  FIG. 2 ; 
         FIG. 5  depicts an exploded view of the alternator of  FIG. 2 ; 
         FIG. 6  depicts a schematic diagram of the circuitry of a first portion of a switch mode rectifier included in an energy control module according to one embodiment of the apparatus of  FIG. 1 ; 
         FIG. 7  depicts a schematic diagram of the circuitry of a second portion of a switch mode rectifier included in an energy control module according to one embodiment of the apparatus of  FIG. 1 ; 
         FIG. 8  depicts a schematic diagram of the circuitry of a third portion of a switch mode rectifier included in an energy control module according to one embodiment of the apparatus of  FIG. 1 ; 
         FIG. 9  depicts a schematic diagram of the circuitry of a multistage feedback loop included in an energy control module according to one embodiment of the apparatus of  FIG. 1 ; 
         FIG. 10  depicts a schematic diagram of the circuitry of a pulse width modulation controller included in an energy control module according to one embodiment of the apparatus of  FIG. 1 ; and 
         FIG. 11  depicts a block diagram showing a water supply environment in which the apparatus of  FIG. 1  may be employed. 
     
    
    
     DETAILED DESCRIPTION 
       FIG. 1  depicts a block diagram of an exemplary embodiment of an auto-regulated motion power system (“AMPS”) device  10 . The AMPS device comprises a three-phase alternator  12  coupled to an energy control module (“ECM”)  14 . The alternator has a rotating high-voltage field winding  18  and a fixed high voltage phase delta connected stationary (stator) winding  20 . The energy control module  14  includes a switch mode rectifier  22 , a multistage feedback loop  24  and a pulse width modulation generator  26 . 
     The alternator has a three-phase high-voltage alternating current wye (Y) output  30  that is connected to a frequency converter  32 , which may have storage and backup options as is known in the art. The output  34  of the frequency converter may be used to drive a load  36 , or the output of the alternator may be connected directly to a non-frequency dependent load  36   a . The alternator includes a pulley assembly  38  (see  FIGS. 2-5 ) on one end that is adapted to be connected to a prime mover  40 , that is, a source of rotating mechanical power such as the shaft of an internal combustion engine or a windmill or some other source of power. 
     As depicted in  FIGS. 2-5 , according to one embodiment, the housing  44  of the alternator  12  holds a cylindrical stator  46  having multiple windings  48  as is typical with alternators. Each winding is wound through two separate laminated steel sections with a gap between each winding. The stator sections or assemblies  50  and  52  are keyed together and operate in phase with each other. 
     The stator assemblies  50  and  52  are wound electrically as a single unit, but the effect is that of two stators wired in series, operating in phase. The gap between the stator assemblies is typically short, so that the copper losses between the assemblies is much less than the losses in the loops at the end of a standard stator. This reduction in losses is an improvement over simply stacking independent alternators. Reducing the inductance in the area where there is no magnetic field to excite the stator material further enhances the output. 
     According to one embodiment, two Lundell type high voltage dual claw pole rotor assemblies  56  and  58  keyed on a common shaft  60 . The entire assembly is rotatably mounted inside the cylindrical stator  46  by a front bearing  64  and a rear bearing  66  between the rear housing  68  of the alternator and the pulley assembly  38  of the alternator. The rotor assemblies are oriented North-South-South-North, meaning one assembly is mounted on the common shaft with its north magnetic pole towards the front (that is, towards the pulley assembly  38 ) and with its south magnetic pole towards the rear (that is, towards the rear housing  68 ) of the alternator. A brush housing  69  mounts to the rear housing  68 . The other rotor assembly is mounted on the common shaft with its south magnetic pole towards the front of the alternator and its north magnetic pole towards the rear of the alternator. Thus, the two south poles of the respective rotor assemblies are adjacent on the common shaft. A gap  70  between the two coils enables the rotor assemblies to develop independent magnetic fields. In other embodiments, only one Lundell claw is used, which reduces size and weight but also reduces the level of output power. 
     The separation of the two rotor assemblies  56  and  58  allows them to develop full magnetic fields, instead of forcing the two like fields in the center of the assembly together, possibly causing stray magnetic fields and a loss of some strength. As a result, when the pulley assembly  38  is spun by the prime mover  40 , the two rotor assemblies rotate within the stator and generate alternating current electricity in the stator. The combination of the magnetically isolated rotor assemblies  56  and  58  powered by an electrically common stator winding  48  excites the mechanically isolated but electrically common stator assemblies  50  and  52 , producing output across a wide rotational speed range. 
     By introducing the gap  70  between the two like poles of the rotor assemblies  56  and  58 , the full magnetic field is able to act on the poles. This is accomplished by introducing a nonmagnetic spacer  76  between the rotor assemblies  56  and  58 . The size of the spacer is a function of the design specifics for the size and output of the alternator. This spacer may be aluminum, composite, plastic or any other nonmagnetic material. To further isolate the rotors&#39; magnetic fields, the shaft may be made from a nonmagnetic alloy such as titanium, some forms of stainless steel, bronze or other material. If the shaft is made from a magnetic material, a sleeve between the rotor assemblies and the shaft made from nonmagnetic material as mentioned above would serve the same purpose. 
     While the rotor assemblies  56  and  58  operate as a direct current electromagnet, the stator assemblies  50  and  52  produce a polyphase alternating current output. The two stator assemblies  50  and  52  in the alternator  12  share a single winding  48  that passes across the gap  70  in the rotor assemblies  56  and  58 . The two stator assemblies are in phase with each other, as are the rotor assemblies. The rotor assemblies operate magnetically as independent units, exciting the two stator segments. 
     The reduction of stray magnetic fields and the reduction of unneeded inductance improve the thermal efficiency of the unit as well. All or a significant portion of the magnetic stresses of closely coupled like fields are dissipated as heat in the unit. The inductance of the stator windings passing through an area of laminations that is not excited also produces heat. The design does not have either situation present. 
     A high-voltage direct current buck converter  82  is connected to the rotor assemblies  56  and  58 . The DC field winding  18  has a positive connection  86  and a negative connection  88 . The positive connection is connected to a positive direct current output of the switch mode rectifier  22  in the energy control module  14 . The negative output  94  of the switch mode rectifier connects to the pulse width modulation high frequency switch  120 . The other side of the high frequency switch connects to the negative connection of the DC field winding  18 . 
     The switch mode rectifier  22  is designed with a wide range voltage input and a regulated output. The current on the leads from the wye (Y) output  30  of the alternator  12  is applied to the three phase input  106  (See  FIG. 6 ) of the switch mode rectifier and is rectified to direct current by a three phase bridge rectifier  108  (See  FIG. 6 ). The direct current is passed to the buck converter  82  (see  FIG. 7 ) that reduces the direct current to a specified output voltage. The positive output voltage is applied to a positive connection  90  on the direct current field winding  18  of the alternator  12  and the negative return  94  is applied to the pulse width modulation generator  26 . 
     The voltage from the wye (Y) output  30  is also applied to the multistage feedback loop  24 . The pulse width modulation generator  26  has a high-frequency pulse width modulation switch  120  connected between the negative return and the negative connection  94  of the DC field winding  18 . The pulse width modulation generator  26  is also connected to an output  126  (See  FIG. 9 ) of the multistage feedback loop  24 . 
     The multi-stage feedback loop  24  monitors the voltage level of the wye (Y) output  30  and uses that information to control the frequency of engagement of the pulse width modulation switch  120  (see  FIG. 10 ). By controlling the frequency or level of engagement of the pulse width modulation switch, the level of generation of power from the alternator  12  is regulated to maintain the voltage on the wye (Y) output  30 . In other words, the pulse width modulation switch  120  turns the alternator DC field winding  18  on and off, thereby regulating the output voltage of the alternator. 
       FIG. 9  depicts a sample schematic for the multistage feedback loop  24  (See  FIG. 1 ).  FIGS. 6 ,  7  and  8  depict sample schematics for portions of the switch mode rectifier  22 .  FIG. 6  shows the supply section.  FIG. 7  shows sample schematics for the buck converter  82 .  FIG. 8  shows sample schematics for the buck control circuit  84 . 
       FIG. 10  depicts sample schematics for the pulse width modulation generator  26 . Often, the alternator  12  must be primed, for example by using an external supply to apply a low-voltage, low current source for initially activating or exciting the alternator. Thus, as shown in  FIG. 10 , the pulse width modulation generator  26  includes circuitry for a primer  134 . However, other priming mechanisms and circuitry may also be used, as would be understood by one of skill in the art. Furthermore, in some embodiments, no priming is required because there may be enough residual magnetism to start up on rotational energy alone. 
     In operation, when the prime mover  40  turns the pulley assembly  38 , the rotor assemblies  56  and  58  inside the alternator  12  rotate inside the stator windings  48 . This creates an electromagnetic field producing current flow through the leads of the wye output  30  to the frequency converter  32 . This electricity is converted to the desired frequency and applied to drive the load  36  or  36   a.    
     The output of the alternator  12  is held constant by the multistage feedback loop  24  connected to the pulse width modulation generator  26 . Thus, the constituent parts of the energy control module  14  (the switch mode rectifier  22 , the multi-stage feedback loop  24 , and the pulse width modulation generator  26 ) monitor the output of the alternator  12  and adjust the voltage of the high-voltage direct current field winding  18 , which varies the magnetic field to control the output voltage to a constant preset value. 
     The alternator assembly design provides (i) increased magnetic fields and reduction of stray fields in the rotor assembly due to the magnetic isolation previously discussed; (ii) increased stator output due to the reduction of copper losses and reduction of inductance in the gap between the segments where no work is being done; and (iii) improved thermal efficiency by reducing stray fields and unneeded inductance, both of which produce heat. The AMPS device  10  provides a high level of AC power for sensitive electronics including computers and medical equipment as well as general equipment. The AMPS device can provide this power over a wide range of rotational input speeds from the primary mover or energy source. This allows users to power equipment, even while in motion as in the case of a vehicle mounted system, or with varying flows in the case of water and wind. The AMPS device can also control and regulate torque while producing said power 
     The AMPS device  10  may be driven by a variety of prime movers  40 . For example, an idling internal combustion engine typically has “excess” power being wasted. By connecting the AMPS apparatus to that engine, a ready supply of AC power may be tapped. 
     Another potential prime mover involves falling water. That is, in a typical municipal water supply, the water begins at high pressure and is gradually brought down in pressure using a series of pressure relief valves before providing the water to a home or office building.  FIG. 11  schematically depicts this reduction in pressure. 
     As depicted in  FIG. 11 , in a typical municipal water supply  140 , a source of elevated water storage  142  releases water down distribution pipes  144 . Pressure relief valves placed at various locations along the pipes relieve the water pressure in the pipes to prevent excess pressure from bursting the pipes. As depicted in  FIG. 11 , those pressure relief valves may be replaced by a series of auto-regulated motion power system (“AMPS”) devices  10 . The excess pressure of the falling water drives a turbine (a prime mover  40 ) connected to the alternator  12 . Driving the alternator takes pressure out of the water line and the alternator produces power that may be used or fed into the electrical grid. 
     The AMPS apparatus  10  also reduces the footprint of both the alternator  12  and the switch mode rectifier  22  compared to traditional generators. Thus, the output power is achieved using less space than many products for equivalent power outputs. The AMPS apparatus may be manufactured with a modular design. This allows for the positioning of module units in various locations of a vehicle or other application uses where space may be limited to accommodate a large unit, but could accommodate several smaller units placed in various locations of the vehicle, thus maximizing power output with limited space. 
     Although the embodiments discussed in this disclosure are described with respect to embodiments involving engine, wind and hydro applications, the present apparatus may be scaled for a wide variety of other applications. Thus, the present invention has several advantages over the prior art. Although embodiments of the present invention have been described, various modifications and changes may be made by those skilled in the art without departing from the spirit and scope of the invention.