A dynamic power optimization system and method for electric submersible motors. A system to optimize operation of an electric submersible motor electrically coupled to a variable speed drive controlled by a computer performing dynamically in a loop the steps of obtaining measurement of a pump performance variable and motor current to establish a first data set, making a motor voltage adjustment of a first type including either an increase or a decrease, establishing a second data set after the adjustment, differencing the first data set with the second data set, and making a second adjustment to the motor voltage of the first adjustment type if the current drops and the pump performance variable is maintained within thresholds, or opposite the first adjustment type if the current rises and the pump performance variable is maintained, or if the current drops and the pump performance variable deviates outside the thresholds.

A resolver converter includes a tracking loop circuit that calculates an angle θ from a resolver output signal, a control and diagnosis circuit that controls the tracking loop circuit and diagnoses based on the resolver output signal, wherein the control and diagnosis circuit, by operating the tracking loop circuit as a direct digital synthesizer (DDS), synchronously detects a noise signal superimposed on the resolver output signal.

A method for controlling a motor-driven pump in communication with a fluid system is provided. Preferably the method employs a frequency drive system to control the motor-driven pump. The control method is characterized in that the operating frequency of the motor can be adjusted very quickly and it is ensured to be operated in a safe frequency range no more than a rated current.

Disclosed are exemplary embodiments of systems and methods for controlling inducer motor speed. In an exemplary embodiment, a method includes changing stator voltage of an inducer motor (e.g., by changing a firing angle of a triac, using a transistor, a silicon controlled rectifier or semiconductor controlled rectifier (SCR), other switching device, etc.); determining actual inducer motor speed (e.g., by using a hall effect sensor or other speed sensor, etc.); and after determining the actual inducer motor speed, changing the motor stator voltage (e.g., by changing the firing angle of the triac, etc.) to a value at which the actual inducer motor speed is controllably regulated and/or maintained substantially at a set speed.

Examples include a method for controlling a synchronous motor using a variable speed drive. The motor includes a permanent magnet rotor generating a magnetic flux. The method includes applying a predefined electrical command signal to the motor and estimating a motor speed in response to the applying of the predefined electrical command signal. The method also includes reaching a desired estimated motor speed and, in response to reaching the desired estimated motor speed, estimating a parameter related to the magnetic flux of the permanent magnet rotor. The method further includes recording the estimated parameter.

A power converting apparatus includes: a rectifying unit configured to rectify an input AC power, a buck converter that is configured to step down a voltage of the rectified power and that is configured to output DC power having the step down voltage, a first inverter that is connected to an output terminal of the buck converter and that is configured to convert the DC power into AC power to drive a first motor, a second inverter that is connected to the output terminal of the buck converter, that is disposed in parallel to the first inverter, and that is configured to convert the DC power into AC power to drive a second motor, and a converter controller configured to control an output voltage of the DC power of the buck converter.

A dynamic power optimization system and method for electric submersible motors. A system to optimize operation of an electric submersible motor electrically coupled to a variable speed drive controlled by a computer performing dynamically in a loop the steps of obtaining measurement of a pump performance variable and motor current to establish a first data set, making a motor voltage adjustment of a first type including either an increase or a decrease, establishing a second data set after the adjustment, differencing the first data set with the second data set, and making a second adjustment to the motor voltage of the first adjustment type if the current drops and the pump performance variable is maintained within thresholds, or opposite the first adjustment type if the current rises and the pump performance variable is maintained, or if the current drops and the pump performance variable deviates outside the thresholds.

A motor drive device includes a single-phase inverter which is an inverter including a plurality of switching elements. The inverter converts a direct-current voltage output from a direct-current power supply into an alternating-current voltage, by operation of the plurality of switching elements operating, and applies the alternating-current voltage to a motor. The motor drive device includes a control power supply outputting power having a voltage lower than the direct-current voltage, by using the direct-current voltage. The motor drive device includes a drive signal generation unit driven by the power. The drive signal generation unit generates drive signals driving the plurality of switching elements, and outputs the generated drive signals to the plurality of switching elements. The motor drive device includes a power supply switch operating so as to allow supply of the power from the control power supply to the drive signal generation unit when a rotation speed of the motor is higher than a threshold. The power supply switch operates so as to stop the supply of the power from the control power supply to the drive signal generation unit when the rotation speed is lower than the threshold.

A motor control circuit includes a control circuit configured to output a pulse width modulation signal for controlling a switching operation of an inverter circuit, the inverter circuit being configured to supply an alternating current power to a motor, and includes a speed-change detecting circuit configured to detect a change in a speed command signal and, output, in response to the change meeting and exceeding a predetermined limit, a signal indicating that the speed command signal has changed to the control circuit to cause the control circuit to change a duty cycle of the pulse width modulation signal, the speed command signal specifying a target value of a rotational speed of the motor.

A method for controlling a motor-driven pump in communication with a fluid system is provided. Preferably the method employs a frequency drive system to control the motor-driven pump. The control method is characterized in that the operating frequency of the motor can be adjusted very quickly and it is ensured to be operated in a safe frequency range no more than a rated current.