Energy storage power source using self-excitation of a wound-rotor induction machine (WRIM) to charge and discharge energy storage elements (ESEs)

Patent metadata

Field	Value
Publication number	US-11929619-B2
Application number	US-202217567611-A
Country	US
Kind code	B2
Filing date	Jan 3, 2022
Priority date	Jan 3, 2022
Publication date	Mar 12, 2024
Grant date	Mar 12, 2024

Abstract

A stored energy power source uses a wound-rotor induction machine (WRIM) to receive energy from a prime mover via a rotating shaft, provide magnetization reactive energy from a self-excited AC capacitor bank, store the energy in N energy storage elements (ESEs) via tertiary windings, and discharge the ESEs to deliver energy via a secondary winding to a load producing output. Each discharging ESE contributes to a total flux at the secondary winding to sum the individual ESEs voltages. These voltages can be stepped up or down by a transformation ratio between the secondary winding and each of the tertiary windings. A flywheel may be coupled to the shaft to store and delivery kinetic energy. Load factor power control can be used to stabilize the output voltage. The source may be configured to allow for the bi-directional flow of energy between the ESEs, the flywheel and the load. The WRIM provides a safe, reliable and efficient system to provide high-level AC and DC output voltages.

First claim

I claim:

1. An energy storage power source, comprising:
a wound-rotor induction machine (WRIM) including N tertiary windings each wound 360/N degrees around a first magnetic core and secondary winding wound 360 degrees around a second magnetic core and coupled to a load producing output, said first and second magnetic cores separated by a radial airgap and configured to rotate relative to each other;
a shaft that is coupled to either the first or the second magnetic core;
a prime mover configured to rotate the shaft and supply motive power to the WRIM;
one or more AC capacitor banks coupled to either a primary winding wound 360 degrees around the first magnetic core or the tertiary windings;
N energy storage elements (ESEs);
N bi-directional AC/DC converters that each couple one of the tertiary windings to a respective one of the energy storage elements;
a WRIM controller,
wherein in a charging state, the prime mover rotates the shaft to magnetize the radial airgap with reactive excitation supplied by the one or more AC capacitor banks to self-excite the WRIM, said one or more AC capacitor banks providing a leading power-factor reactive power to balance the lagging power-factor reactive power required to magnetize the radial airgap and leakage inductances of the windings on the first magnetic core and to excite the tertiary windings to provide controlled power through the AC/DC converters to selectively charge the N ESEs; and
wherein in a discharge state, at least some capacity of the N ESEs are discharged back through the AC/DC converters to excite the tertiary windings to create a revolving magnetic field to magnetize the radial airgap and to supply real power to the second magnetic core to individually contribute to a total machine magnetic flux to magnetize the secondary winding to induce an AC output voltage on the secondary winding proportional to the sum of the voltages from the discharging ESEs and deliver a portion of the N ESEs energy capacity as electrical energy to the load producing output.

2. The energy storage power source of claim 1 , wherein said WRIM includes the primary winding wound 360 degrees around the second magnetic core, wherein said one or more AC capacitor banks are coupled to the primary winding to magnetize the radial airgap and provide reactive compensation to leakage inductance of the primary winding.

3. The energy storage power source of claim 2 , wherein the primary winding the primary winding is segmented into M primary windings, each primary winding is coupled to a different one of the AC capacitor banks such that a reactive current circulates between the primary winding and the respective capacitor bank, each primary winding is magnetically coupled to one or more of the tertiary windings, wherein the WRIM controller is configurable to simultaneously charge one or more ESEs coupled to a first subset of the M primary windings and to discharge one or more ESEs coupled to a second subset of the M primary windings in which the first and second subsets do not overlap.

4. The energy storage power source of claim 1 , wherein a plurality of said AC capacitor banks are coupled to a respective plurality of tertiary windings.

5. The energy storage power source of claim 4 , wherein the WRIM controller is configurable to independently charge or discharge the ESEs coupled to different tertiary windings and AC capacitor banks.

6. The energy storage power source of claim 1 , wherein the AC output voltage of the secondary winding is scaled by a transformation ratio determined by turns ratios of the secondary winding to the N tertiary windings.

7. The energy storage power source of claim 6 , wherein the transformation ratio is on average for all N ESEs greater than 1:1 to increase the AC output voltage.

8. The energy storage power source of claim 1 , wherein the load producing output is configured for a bi-directional flow of energy, wherein the WRIM is configured to selectively receive energy from the load producing output to charge the ESEs.

9. The energy storage power source of claim 8 , further comprising:
a flywheel coupled to the shaft, said flywheel configured to selectively store energy from the prime mover, the ESEs or the load producing output via the secondary winding and to selectively deliver energy to at least the ESEs and the load producing output via the secondary winding.

10. The energy storage power source of claim 1 , wherein the N ESEs are electrically isolated from each other.

11. The energy storage power source of claim 1 , wherein the N bi-directional AC/DC converters are independently controllable to selectively charge one or more ESEs exclusively or (XOR) independently controllable to selectively discharge the one or more ESEs.

12. The energy storage power source of claim 1 , further comprising:
a load factor power controller coupled to the load producing output to modulate an inductive-resistive load to actively adjust a power factor of the WRIM to vary a rotational speed of the shaft and maintain the AC output voltage of the secondary winding within a specified tolerance of a target voltage.

13. The energy storage power source of claim 1 , further comprising:
a flywheel coupled to the shaft to store energy and to deliver kinetic energy to the ESEs, the load producing output or to maintain or accelerate the rotation of the shaft.

14. The energy storage power source of claim 13 , wherein the WRIM controller is configured to discharge one or more ESEs to deliver energy to the load producing output with a first discharge time constant and decelerate the flywheel to deliver energy to the load producing output at a second discharge time constant wherein the second discharge time constant is longer than said first discharge time constant.

15. The energy storage power source of claim 14 , wherein the WRIM controller is configured to charge the one or more ESEs with a first charging time constant and to accelerate and charge the flywheel to store energy at a second charging time constant wherein the second charging time constant is shorter than said first charging time constant, wherein said WRIM can store energy in the flywheel and ESEs from the prime mover having a specified peak power and can deliver energy to the load producing output with a transient peak power greater than the specified peak power.

16. The energy storage power source of claim 1 , wherein in the discharging state the WRIM controller is configured to selectively decouple the prime mover from the shaft.

17. The energy storage power source of claim 1 , wherein in the discharging state the WRIM controller is configured to leave the prime mover coupled to the shaft to deliver additional energy via the secondary winding to the load producing output.

18. The energy storage power source of claim 1 , wherein a rotor assembly includes a secondary winding wound around a second magnetic core and a stator assembly includes a primary winding wound around a first magnetic core, wherein two said rotor assemblies are connected to the shaft and to the prime mover, each rotor assembly operating within a separate stator assembly, wherein each stator assembly has N1 and N2 distinct ESEs and N1 and N2 tertiary windings magnetically coupled to two or more independent load producing outputs.

19. An energy storage power source, comprising:
a wound-rotor induction machine (WRIM) including a primary winding wound 360 degrees around a stationary magnetic core, a secondary winding wound 360 degrees around a rotating magnetic core separated from the stationa

Assignees

• Raytheon Co

Inventors

• Kuznetsov Stephen B

Classifications

• H02J15/30

  using storage of inertial or mechanical energy, e.g. using flywheels · CPC title

• H02P2207/01

  Asynchronous machines · CPC title

• H02J2207/20

  Charging or discharging characterised by the power electronics converter · CPC title

• H02K7/025

  for power storage · CPC title

• H02M5/16

  for conversion of frequency · CPC title