Patent Application
20140375405
The present teachings relate to systems and methods for an inductively coupled damper for direct current power systems, and more particularly, to platforms and techniques for eliminating alternating current noise and other spurious components in power source signals supplied to an inverter used to drive an electrically powered generator, such as those used to start engines.
In aircraft applications and others, the turning shaft of a jet engine or other power plant can be used to drive a generator to supply electrical power to the airframe. Various signal conditioning circuits can be used to achieve desired direct or alternative voltages for those types of applications. In addition, besides acting as a source for internal power, the main generator can also be used to start the engine during initial operation. To perform that additional role, the generator must be fed with a sufficient source of direct current power which is passed through an inverter to generate a compatible alternative current source to turn the power shaft of the engine.
However, when an inverter is coupled to a direct current power source, such as an onboard battery with sufficient current reserves, signal passing from the DC power source to the inverter can become affected or degraded by a host of spurious signal components. Some of that noise can be introduced by undesired or unpredicted resonant harmonics produced by the interaction of any of the power source, inverter, generator, and/or load. When those artifacts are severe enough, the engine control electronics may abort the engine starting sequence, or take other actions.
It may be desirable to provide methods and systems for an inductively coupled damper for direct current power systems, in which a generator coupled to the power shaft of an engine can be fed with reliable direct current power signals, to enable the generator to effectively and reliably start the attached engine.
Disclosed herein is an electrical system that includes a first interface to a direct current power source and a second interface to an inverter. The inverter is coupled to a generator. An inductive damper is coupled to the direct current power source via the first interface and to the inverter via the second interface. The inductive damper comprises a primary winding, a secondary winding, and a resistor coupled to the secondary winding. The inductive damper operates to galvanically isolate the resistor from the direct current power source during a startup operation of the generator.
Also disclosed herein is a method of inductively damping a power source. A source current is received from a direct current power source. The current passes through an inductive damper to a generator. The inductive damper comprises a primary winding, a secondary winding, and a resistor coupled to the secondary winding. The inductive damper operates to galvanically isolate the resistor from the direct current power source during a startup operation of the generator;
The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the present teachings and together with the description, serve to explain the principles of the present teachings. In the figures:
Embodiments of the present teachings relate to systems and methods for an inductively coupled damper for direct current power systems. More particularly, embodiments relate to platforms and techniques for configuring a power system for aircraft or other applications, in which signals from a DC power source can be conditioned to reduce or eliminate spurious harmonics and other signal artifacts, for purposes of using an onboard generator to supply power to a power shaft and begin an engine start-up sequence.
Reference will now be made in detail to exemplary embodiments of the present teachings, which are illustrated in the accompanying drawings. Where possible the same reference numbers will be used throughout the drawings to refer to the same or like parts.
The generator 104 and associated circuitry can be configured to be powered by engine operation to deliver electrical power, and also to receive electrical power to turn the engine over during startup operation. As shown for instance in
The inductive damper 208 produces filtering or damping effects against unwanted spurious power harmonics, in part due to inductive coupling of the DC power source 206 to the inverter 210. An exemplary construction of the inductive damper 208 is shown in
Using the inductive damper 208, including the inductively coupled resistor 314, no direct or galvanic connection to the feed from the DC power source 206 is required so that the wire insulation itself provides all the dielectric value. Further, there is no additional resistance to the DC component on the feeder line, so that there is no additional dissipation. Moreover, by use of the turns ratio between the primary winding 310 and the secondary winding 312, the ohmic value and the operating current of the resistor 314 can achieve a desired dissipation, at a comparatively reduced weight of the overall system. Other advantages include the fact that under a short or other fault condition, the resistor 314 can be protected from overstress by the saturation characteristics of the magnetic core around which the primary winding 310 and secondary winding 312 are constructed, providing increased durability and robustness.
The foregoing description is illustrative, and variations in configuration and implementation may occur to persons skilled in the art. For example, while embodiments have been described in which a single inductive coupler 208 provides damping and protection to a single generator 204, in implementations, multiple inductive couplers can be combined in various serial or parallel configurations. Similarly, while the output of the inductive damper 208 is illustrated as being communicated to one inverter 210, in implementations, that output can be communicated to multiple inverters and/or other components. Other resources described as singular or integrated can in embodiments be plural or distributed, and resources described as multiple or distributed can in embodiments be combined. Further modifications may be made to adapt a particular situation or material to the teachings of the disclosure without departing from the essential scope thereof. Moreover, the use of the terms first, second, etc., do not denote any order or importance, but rather the terms first, second, etc. are used to distinguish one element from another. Furthermore, the use of the terms a, an, etc. do not denote a limitation of quantity, but rather denote the presence of at least one of the referenced item. The scope of the present teachings is accordingly intended to be limited only by the following claims.
| Number | Date | Country | |
|---|---|---|---|
| 61838079 | Jun 2013 | US |
