Ocean Power Technologies, Inc.

Hasbro, Inc.

Paul J Smalser

George W Taylor

Joseph R Burns

Thomas R Welsh

David B Stewart

Charles B Carroll

Henry I Schanzer

Kerry D O'Mara

In a linear electric generator (LEG) which includes apparatus for passing a permanent magnetic assembly (PMA) along linearly disposed sections of coils of an induction coil assembly (ICA) for generating voltages and power, a switching arrangement for coupling only selected sections of coils of the ICA across the power output lines of the LEG. The selected coil sections include the sections of coils of the ICA in close proximity to the passing PMA. In accordance with different embodiments, the non selected coils of the ICA may be either short circuited or disconnected (open circuited) from the power output lines.

Coil switching circuit for linear electric generator

A wave energy converter (WEC) including an electric generator for capturing energy contained in ocean waves and converting it to electrical energy at the output of the electric generator may be characterized as an effective capacitive (or inductive) element. Systems embodying the invention include an inductive (or capacitive) element inserted in the circuit between the output of the electric generator and a load in order to achieve resonance with the effective capacitance (inductance) of the WEC and so as to increase the efficiency of the power transfer to the load. In certain embodiments the load coupled to the system has an optimum value which is made a function of the frequency of the ocean waves and the effective capacitance (or inductance). The effective capacitance (inductance) of the converter varies as a function of the frequency of the ocean waves. Accordingly, systems embodying the invention may include a controller for varying the load and/or the inductive (capacitive) element coupled in the system to resonate with the converter for increasing the efficiency of the system.

Apparatus and method for optimizing the power transfer produced by a wave energy converter (WEC)

Protection against damage caused by excessively high input energies, e.g., from ocean storms, is provided in energy converting systems by, in response to the detection of excessively high input energies, changing the electrical impedance of the electrical load to which power from an electrical generator is being delivered for increasing the generator output current for reducing the power converting efficiency of the generator. This increases the mechanical impedance presented by the generator to the source of input energy for reducing the motion producing effect of the input energy.

Protection arrangement for natural energy power generation systems

A transducer operated as power generating device is driven at a low frequency and collects energy at the low frequency rate. The collected energy is extracted at a much higher frequency. Extracting the energy at a higher frequency enables the use of components, such as inductors, having reasonable values and sizes. In one embodiment, a power extracting circuit which includes elements designed to resonate with the transducer at a higher frequency than the frequency at which the transducer is being driven is periodically switched in circuit with the transducer. Thus, the electric power generator device operated and controlled by a slowly changing source of energy (e.g., ocean waves, wind, eddies of water) may develop energy at one frequency and may be operated to transfer the energy at another frequency. The resonating circuit is switched into circuit with the transducer on the positive and negative peaks of the force driving the transducer for a time approximately equal to Tc, where Tc is equal to approximately &frac12;fo, where fo is the resonant frequency of the circuit with the switch closed. In another embodiment the load applied to the circuit is designed to have an optimum value to optimize the power transfer. Other embodiments include circuits for reliably and accurately detecting the peak(s) of the driving input signals.

Switched resonant power conversion electronics

Energy from a naturally recurring source of variable mechanical energy is captured and transmitted to an electrical generator causing it to rotate at speeds proportional to the amount of energy captured. The output voltage produced by the generator is a function of the rotational speed imparted to the generator and a load impedance which is coupled via controllable switching circuitry to the generator output. The effective load impedance is varied and controlled by means of a control mechanism responsive to the rotational speed of the generator and the output voltage of the generator which selectively turns the controllable switching circuitry on and off.

Electric power generating system

The electric energy generated by a piezoelectric device (PEG), when mechanically stressed, is transferred from the PEG to a storage element (e.g., a capacitor or a battery) by selectively coupling an inductor in the conduction path between the PEG and the storage element. In one embodiment, the transfer of energy is optimized by allowing the amplitude of the electric signal to reach a peak value before transferring the electrical energy via an inductive network to a capacitor or a battery for storage. Electrically, the PEG is operated without a significant loading (e.g., essentially open circuited) when the amplitude of the voltage generated by the PEG is increasing. When the amplitude of the voltage has peaked, or reached a predetermined value, the electrical energy generated by the PEG is coupled to an inductive-capacitive network for absorbing and storing the energy produced by the PEG.

Power transfer of piezoelectric generated energy

An input device for computers or electronic games using piezoelectric elements. Four piezoelectric devices are mounted on a base in positions ninety degrees apart. A user actuation element, such as a directional control pad and or a joystick is pivotally disposed on the base above the piezoelectric sensors. A biasing element such as a spring, foam or rubber element is positioned between the actuation element and the base to support the actuation device in a neutral position when no face is being applied by a user to also return the activation element to its neutral position after a user's force is removed. Opposing sensors are connected to a bridge circuit such that in the neutral position of the actuation element the output voltage of the bridge is one half of the input voltage. As the user applies a force to the actuation device, the resistance of one or the other (opposing) piezoresistive device will decrease and accordingly drive the output of the bridge circuit either towards the input voltage or ground, depending on which sensor the user is activated. Additionally a piezoresistive device constructed according to the present invention uses a conductive foam overlayed on top of a series of circuit traces which describe open circuits. As the conductive foam is compressed, it will complete the circuit of the circuit traces and provide an output voltage varying with the compression of the foam.

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Hamilton Square, NJ, United States of America

Paul J Smalser