The present invention generally relates to the field of power transformation, in particular a transformer with a transducer as a primary or secondary and a magnetic winding as the secondary or primary. The present invention relates to an apparatus for the conversion of power providing isolation as well as voltage conversion.
There are several forms of transformer today. In general, a transformer is useful in many situations. For example, converting between one voltage and another; isolating voltages; and floating an input source. Most transformers consist of two or more coils of wire wound around a magnetic core. The input coil is called the primary and the output coil(s) is called the secondary. By applying an alternating current on the primary coil, a magnetic field is created upon the magnetic core, inducing an output voltage on the secondary core. By applying an AC voltage on the primary, a second AC voltage will result on the secondary. Depending on the ratio of the number of turns in the primary to the number of turns in the secondary, the transformer may either step-up or step-down the voltage. Because there is substantially no electrical conductance between the primary and secondary, the output voltage on the secondary will be electrically isolated from the primary. Besides isolating the input from the output, increases or decreases in voltage potential between the primary and secondary can be realized. Some magnetic transformers have solid iron cores, some have laminated cores, sometimes, the magnetic interface is between the primary and secondary is not a magnetic core, perhaps just a primary and a secondary winding in close proximity to each other. Sometimes the core is a continuous circle of magnetic material, known as a torroid transformer. Magnetic transformers are useful in a wide range of voltage conversion.
Another technology for transforming electricity is a piezoelectric transformer. These transformers use one piezoelectric element with three or four terminals to form a transformer. A piezoelectric transformer is a type of AC voltage multiplier. A piezoelectric transformer uses acoustic coupling to couple an input side to an output side. An input voltage is applied across a short length of a bar of piezoelectric material, creating an alternating stress in the bar and causing the whole bar to vibrate. The vibration frequency may be selected to be the resonant frequency of the bar, typically in the 100 kilohertz to 1 megahertz range. An output voltage is then generated across another section of the bar by piezoelectric effect. Step-up ratios of more than 1000:1 and step down ratios of 1:10 may be possible.
In practice, these transformers usually provide an input-to-output voltage range of possibly 0.1 to 1000. Given a fixed input voltage of X volts, a transformer could be designed to generate output voltages from X/10 volts to 1000X volts. This range is somewhat limiting. For example, if working with AC line voltages, the lowest secondary voltage might be around 12 VAC in the United States (120V/10), and possible 22V (220/10) in counties where the standard power source is 220V. Magnetic transformers don't share this limitation, in that, depending on the ratio of windings; almost infinite step-up or step-down ratios are possible. For example, there are transformers that accept 120 VAC on their primary and output 5 VAC on their secondary. There are photoflash transformers for initiating the flow of current in Xenon flash tubes that generate many thousands of volts from a very low voltage input pulse, perhaps 5 volts.
Although the aforementioned transformers provide different methods to convert one electrical voltage to another, each has its limitations. Magnetic transformers are bulky, have higher mass and are inefficient. Piezoelectric transformers have less mass, but don't provide a very dynamic range of voltage increase or decrease and do not provide isolation.
A solution to the problems described and other problems is a transformer of the resent invention. In this invention, either the primary or the secondary of the transformer is made from a transducer and the other (secondary or primary) is made from a magnetic coil. In an embodiment of the present invention, both the primary and secondary are made from transducers, possibly separated by a rigid energy transfer member. In another embodiment, the transducer is a piezoelectric element. In another embodiment of the present invention, the transducer is a micro machine and the secondary is either a piezoelectric element or a magnetic coil. An example of such a micro machine is the micro-scale motor developed by a UC Berkeley physicist, the first nano-scale motor—a gold rotor on a nanotube shaft that is small enough to ride on the back of a virus.
In another embodiment of the present invention, the primary of the transformer is a piezoelectric element, or possibly a micro machine. The piezoelectric element or micro machine is coupled to a magnetized material or permanent magnet, for example, magnetized iron. The magnetized material or permanent magnet is disposed near or within a secondary coil, perhaps said secondary coil is windings of wire or a loop of paths on a printed circuit board or integrated circuit substrate. As a voltage is applied to the primary, the piezoelectric element deforms or the micro machine creates motion, moving the magnetized material within or near the secondary coil, thus producing an electric field within the secondary coil. Since there is no direct connection between the primary and the secondary, this invention may also provide isolation between the primary and the secondary.
In another embodiment of the present invention, the primary of the transformer is a piezoelectric element or micro machine. The piezoelectric element or micro machine is coupled to a magnetized material, for example, magnetized iron. The magnetized material is then disposed near or within a plurality of secondary coils. As a voltage is applied to the primary, the piezoelectric element deforms or the micro machine creates motion, moving the magnetized material within or near the secondary coils, producing an electric field within each of the plurality of the secondary coils. Since there is no direct connection between the primary and the secondary(s), this invention may also provide isolation between the primary and the secondary.
In another embodiment of this invention, a primary piezoelectric element is coupled to a secondary piezoelectric element with an energy transfer member, preferable a stiff material such as plastic, nylon, wood, hard rubber, etc. If the transfer member is made from an insulator such as nylon, it may allow energy in the form of force generated by an AC voltage applied to the primary piezoelectric element to transfer to the secondary piezoelectric element, producing an electric voltage on the secondary in response to this movement. This transfer member may provide isolation between the primary and the secondary while allowing energy to transfer between them.
In another embodiment of the present invention, the primary of the transformer is a conductive coil. A magnetic material, perhaps iron or steel, is then disposed near or within the conductive coil. As a voltage is applied to the primary, the conductive coil generates a magnetic field, moving the magnetic material, thus producing movement much like that of a magnetic doorbell. The magnetic material is coupled to a piezoelectric element and this movement is converted into an electrical voltage in response to the stimulus from the movement of the magnetic material by the piezoelectric effect. Since there is no direct connection between the primary and the secondary, this invention provides isolation between the primary and the secondary. In a further embodiment of this invention, the magnetic material is coupled to the piezoelectric element with an insulative material, preferable a stiff material such as plastic, nylon, wood, hard rubber, etc. The insulative material allows the piezoelectric element to move as the magnetic material moves in response to changes in input voltage and transfers energy to the piezoelectric element, producing an electric voltage on the secondary in response to this movement. This insulative material may provide even greater isolation between the primary and the secondary.
In another embodiment, a piezoelectric-piezoelectric transformer, a voltage is applied to the first piezoelectric-electric element, causing it to change shape, exerting a force on a coupling between that element and a second piezoelectric element and therefore, placing a force on the second piezoelectric element. In response to the force, the second piezoelectric element is deformed, causing a second voltage on its output. By selecting a certain size piezoelectric element for the primary and secondary, voltage increases or decreases can be accomplished. Likewise, if the coupling member is an insulator, then the primary will be isolated from the secondary. This type of transformer is useful for converting voltages within a limited range, because of the limitations on piezoelectric element size and structure.
It is to be understood that both the forgoing general description and the following detailed description are exemplary only and are not restrictive of the invention as claimed. The general functions of this invention may be combined in different ways to provide the same functionality while still remaining within the scope of this invention.
The numerous advantages of the present invention may be better understood by those skilled in the art by reference to the accompanying figures in which:
Reference will now be made in detail to the presently discussed embodiment of the invention, an example of which is illustrated in the accompanying drawings.
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It is believed that the present invention and many of its attendant advantages will be understood by the forgoing description. It is also believed that it will be apparent that various changes may be made in the form, construction and arrangement of the components thereof without departing from the scope and spirit of the invention or without sacrificing all of its material advantages. The form herein before described being merely an explanatory embodiment thereof. It is the intention of the following claims to encompass and include such changes.