Waveform generator for driving electromechanical device

A method for driving an electrostrictive or magnetostrictive transducer, comprising:

• applying an amplifier output voltage across said transducer;
• processing a feedback signal from said transducer to determine amplitude and phase characteristics of said feedback signal;
• using the determined amplitude and phase characteristics to calculate a motional voltage of a transducer equivalent circuit having capacitive, inductive and resistive components;
• modifying said output voltage by the calculated value of said motional voltage;
• and
• feeding a current to said transducer in an amount to maintain the voltage drop across said transducer at the modified value of said output voltage,
• wherein said output voltage has an output frequency, the processing of said feedback including using the output frequency as a reference wave comprised of a pure fundamental sinusoid of the output frequency in a Fourier decomposition with the feedback signal to determine the phase and amplitude of the fundamental sine wave.

An electronic generator to drive an electromechanical load, comprising:

• a. a waveform generator component digitally synthesizing an electrical waveform of a desired frequency;
• b. an amplifier section connected at a control input to an output of said waveform generator component, said amplifier section adjusting at least one of a voltage and a current of said waveform and generating an output waveform of a desired type and for delivery to input leads of the electromechanical load;
• c. computing means operatively connected at least indirectly to said waveform generator component for analyzing voltage and current information and generating a control signal fed to said waveform generator component;
• d. said computing means being programmed to process voltage and current waveform information to determine at least a phase difference between voltage and current waveforms,
• e. said computing means being further programmed to compare the determined phase difference to a phase difference command and to generate a phase error signal fed at least indirectly to said waveform generator component for causing same to adjust its output frequency to result in a predetermined operating point as a function of phase,
• f. said computing means being additionally programmed to compare at least one of voltage and current amplitude respectively to a voltage amplitude command and a current amplitude command and generate an amplitude error signal for inducing said amplifier section to change its output amplitude to result in a predetermined amplitude for a respective one of said voltage and current waveforms,
• g. said computing means being also programmed to process a feedback signal from the electromechanical load to determine amplitude and phase characteristics of said feedback signal, the processing of said feedback signal including using said output frequency as a reference wave comprised of a pure fundamental sinusoid of the output frequency in a Fourier decomposition with the feedback signal to determine said phase difference and said one of said voltage and current amplitude as functions of the phase and amplitude of the fundamental sine wave.

An electronic generator to drive an electromechanical load having at least one feedback crystal or coil, comprising:

• a. a waveform generator component digitally synthesizing an electrical waveform of a desired frequency;
• b. an amplifier section connected at a control input to an output of said waveform generator component, said amplifier section adjusting at least one of a voltage and a current of said waveform and generating an output waveform of a desired type and for delivery to input leads of the electromechanical load;
• c. computing means operatively connected at least indirectly to said waveform generator component for analyzing voltage and current information and generating a control signal fed to said waveform generator component;
• d. said computing means accessing a memory for storing digitized voltage and current waveform information from said amplifier section and voltage and current waveform information from said feedback crystal or coil,
• e. said computing means being programmed to process the voltage and current waveform information in said memory to determine at least a phase difference between a feedback signal from said feedback crystal or coil and the voltage or current waveform across the electromechanical load,
• f. said computing means being further programmed to compare the determined phase difference to a phase difference command and to generate a phase error or correction signal fed at least indirectly to said waveform generator component for causing same to adjust its output frequency to result in a predetermined operating point as a function of phase,
• g. said computing means being additionally programmed to compare the amplitude of the signal from said feedback crystal or coil to a feedback amplitude command and generate an amplitude error signal for inducing said amplifier section to change its output amplitude to result in a predetermined amplitude level,
• h. said computing means being also programmed to process the voltage and current waveform information using said output frequency as a reference wave comprised of a pure fundamental sinusoid of the output frequency in a Fourier decomposition with the voltage and current waveform information in said memory to determine said phase difference and a voltage or current amplitude of the signal from said feedback coil or crystal as functions of the phase and amplitude of the fundamental sine wave.

A method for driving an electromechanical load, comprising:

• i. digitally synthesizing an electrical waveform of a desired frequency;
• ii. feeding said electrical waveform to a control input of an amplifier section;
• iii. operating said amplifier section to adjust at least one of a voltage and a current of said electrical waveform and generate an output waveform of a desired type;
• iv. delivering said output waveform to input leads of the electromechanical load, thereby applying analog voltage and current waveforms across the electromechanical load;
• v. automatically analyzing voltage and current information and generating a control signal therefrom, the generating of said electrical waveform being responsive to said control signal;
• vi. the analyzing of said voltage and current information including processing stored digitized voltage and current waveform information to determine at least a phase difference between said voltage and current waveforms,
• vii. the analyzing of said voltage and current information further including comparing the determined phase difference to a phase difference command and generating a phase error signal;
• viii. automatically adjusting an output frequency of said electrical waveform to result in a predetermined operating point as a function of phase,
• ix. the analyzing of said voltage and current information further including comparing at least one of voltage and current amplitude respectively to a voltage amplitude command and a current amplitude command and generating an amplitude error signal;
• and
• x. operating said amplifier section to automatically adjust an amplitude of said output waveform to result in a predetermined amplitude for a respective one of said voltage and current waveforms.