Abstract: Systems and methods for reliably communicating data between surface and downhole equipment over a power cable, regardless of the length of the power cable, wherein a transmitter modulates a common data stream onto multiple high frequency carrier signals, each of which has a different frequency. Each of the different frequencies is best suited to communication over a different length of cable. The resulting modulated high frequency data signals are impressed on the power cable and are recovered from the cable by a receiver. The receiver is configured to recover signals at each of the different carrier frequencies, at least one of which should be transmitted with little enough attenuation and interference that the data stream can be accurately recovered from the corresponding modulated high frequency data signal.

Abstract: Borehole instruments are powered by AC instrument power transmitted on all three phases of a power cable concurrently carrying three phase motor power, the instrument power transmitted at a multiple of the motor power frequency and having a corresponding fraction of the motor power voltage, and received via a capacitive coupling sufficient to withstand high-voltage cable insulation testing. The phase-to-neutral motor power provides approximately the same power level to the borehole instruments if a phase shorts to ground.

Abstract: Systems and methods for reliably communicating data between surface and downhole equipment over a power cable, regardless of the length of the power cable, wherein a transmitter modulates a common data stream onto multiple high frequency carrier signals, each of which has a different frequency. Each of the different frequencies is best suited to communication over a different length of cable. The resulting modulated high frequency data signals are impressed on the power cable and are recovered from the cable by a receiver. The receiver is configured to recover signals at each of the different carrier frequencies, at least one of which should be transmitted with little enough attenuation and interference that the data stream can be accurately recovered from the corresponding modulated high frequency data signal.

Abstract: Embodiments of the present invention beneficially provide circuits and methods which isolate downhole electronics of a well pump assembly from a power surge. The pump assembly includes a motor and a housing, including head, base, and manifold plate. The head has a hollow interior and a shoulder. The head is mounted to the motor so that, in operation, oil from the motor fills the interior of the head. The base has an outside diameter to fit snugly inside the head. The manifold plate is located between an upper end of the base and the shoulder of the head so that the axis of the manifold plate is perpendicular to the axis of housing. A gauge circuit and an isolation circuit are mounted to the manifold plate. The isolation circuit includes active semiconductor elements to detect excessive voltage and to protect the gauge circuit from the excessive voltage.

Abstract: Borehole instruments are powered by AC instrument power transmitted on all three phases of a power cable concurrently carrying three phase motor power, the instrument power transmitted at a multiple of the motor power frequency and having a corresponding fraction of the motor power voltage, and received via a capacitive coupling sufficient to withstand high-voltage cable insulation testing. The phase-to-neutral motor power provides approximately the same power level to the borehole instruments if a phase shorts to ground.

Abstract: Embodiments of the present invention beneficially provide circuits and methods which isolate downhole electronics of a well pump assembly from a power surge. The pump assembly includes a motor and a housing, including head, base, and manifold plate. The head has a hollow interior and a shoulder. The head is mounted to the motor so that, in operation, oil from the motor fills the interior of the head. The base has an outside diameter to fit snugly inside the head. The manifold plate is located between an upper end of the base and the shoulder of the head so that the axis of the manifold plate is perpendicular to the axis of housing. A gauge circuit and an isolation circuit are mounted to the manifold plate. The isolation circuit includes active semiconductor elements to detect excessive voltage and to protect the gauge circuit from the excessive voltage.

Abstract: A sine wave filter including an inductor for each phase (three inductors) and three delta- or Y-connected capacitors is employed within a borehole power system, coupled within a three phase power system at the surface between the output of a variable frequency drive and a three phase power cable transmitting power to a borehole location, and boosts the output voltage of the drive. The sine wave filter is designed to have a resonant frequency higher than the maximum operational frequency of the drive, and a Q such that, at the maximum operational frequency of the drive, the filter provides a voltage gain equal to the ratio of the desired voltage to the drive's maximum output power at the maximum operational frequency. The sine wave filter also smooths the voltage waveform of a pulse width modulated variable frequency drive.

Abstract: A sine wave filter including an inductor for each phase (three inductors) and three delta- or Y-connected capacitors is employed within a borehole power system, coupled within a three phase power system at the surface between the output of a variable frequency drive and a three phase power cable transmitting power to a borehole location, and boosts the output voltage of the drive. The sine wave filter is designed to have a resonant frequency higher than the maximum operational frequency of the drive, and a Q such that, at the maximum operational frequency of the drive, the filter provides a voltage gain equal to the ratio of the desired voltage to the drive's maximum output power at the maximum operational frequency. The sine wave filter also smooths the voltage waveform of a pulse width modulated variable frequency drive.

Abstract: A recirculating type analog to digital converter is disclosed which has an auto-zero mode that is introduced prior to each conversion cycle. The loop is based on an arrangement of operational amplifiers and FET switches, and further includes a comparator circuit, a reference voltage source and a microprocessor which are coupled to the loop. Also coupled to appropriate points in the loop are three time gated integrator circuits which generate analog signals which respectively compensate for offset voltages of operational amplifiers in the loop, the offset voltage of the comparator circuit which is coupled to this loop, and the gain of the loop. The compensating signals which are generated in the auto-zero mode are applied to the loop during the conversion cycle.

Abstract: A waveform generator is provided which is capable of generating simultaneously a plurality of electrical signals which have different waveforms. The waveform generator is completely battery operated and is particularly useful in testing multichannel devices where power is not available for standard waveform generators. A voltage regulation circuit is provided which provides a regulated voltage from a battery pack for use by the waveform generator. The forward voltage-current characteristics of the base emitter junction of a silicon transistor are used as the basis for the generation of a reference voltage for the voltage regulation circuit to thereby substantially minimize the battery drain caused by the use of a voltage regulation circuit.

Abstract: A waveform generator is provided which is capable of generating simultaneously a plurality of electrical signals which have different waveforms. The waveform generator is completely battery operated and is particularly useful in testing multichannel devices where power is not available for standard waveform generators. A voltage regulation circuit is provided which provides a regulated voltage from a battery pack for use by the waveform generator. The forward voltage-current characteristics of the base emitter junction of a silicon transistor are used as the basis for the generation of a reference voltage for the voltage regulation circuit to thereby substantially minimize the battery drain caused by the use of a voltage regulation circuit.

Abstract: A waveform generator is provided which is capable of generating simultaneously a plurality of electrical signals which have different waveforms. The waveform generator is completely battery operated and is particularly useful in testing multichannel devices where power is not available for standard waveform generators. A voltage regulation circuit is provided which provides a regulated voltage from a battery pack for use by the waveform generator. The forward voltage-current characteristics of the base emitter junction of a silicon transistor are used as the basis for the generation of a reference voltage for the voltage regulation circuit to thereby susbtantially minimize the battery drain caused by the use of a voltage regulation circuit.

Abstract: A waveform generator is provided which is capable of generating simultaneously a plurality of electrical signals which have different waveforms. The waveform generator is completely battery operated and is particularly useful in testing multichannel devices where power is not available for standard waveform generators. A voltage regulation circuit is provided which provides a regulated voltage from a battery pack for use by the waveform generator. The forward voltage-current characteristics of the base emitter junction of a silicon transistor are used as the basis for the generation of a reference voltage for the voltage regulation circuit to thereby substantially minimize the battery drain caused by the use of a voltage regulation circuit.

Abstract: An analog signal representative of the condition of a process variable and an analog set point signal representative of the desired value of the process variable are compared to provide an analog error signal. In response to the analog error signal the controller generates a sign signal and a pulse rate signal which can be utilized to increase or decrease the digital value stored in a counter from which a process control signal is generated. In a preferred embodiment the process controller of the invention is utilized as a backup controller for a direct digital control system and utilizes the same digital output, digital to analog conversion, and analog output components as the associated direct digital controller.