Abstract: This disclosure is drawn to methods, systems, devices and/or apparatus related to power control in applications over long cables. Specifically, the disclosed methods, systems, devices and/or apparatus relate to power control that considers the maximum power available at the end of a long cable (or from a battery) to a load over a broad range of load conditions. Some example systems may include a power supply located at the Earth's surface and a power converter coupled to the power supply via a cable having a first end coupled to the power supply and a second end coupled to the power converter. Some example power converters may be configured to measure the power being consumed by the electrical load in the well, and adjust operating parameter(s) of the electrical load based, at least in part, on the maximum power available at the second end of the cable.

Abstract: A method for controlling a motor is provided. The method comprises obtaining electrical signals of the motor with a signal unit, the electrical signals comprising a motor torque and an angular velocity, calculating a voltage phase angle of a voltage vector with a calculating component, wherein a command torque, the motor torque, the angular velocity and a voltage amplitude of the voltage vector are inputs of the calculating component, and wherein the voltage phase angle is a variable and the voltage amplitude is a constant. The method further comprises modulating the voltage phase angle and the voltage amplitude to a switching signal for controlling an inverter; converting a direct current voltage to the voltage vector according to the switching signal, and applying the voltage vector to the motor.

Abstract: A rotation speed control circuit is disclosed. The rotation speed control circuit includes a temperature-controlled voltage duty generator, a pulse-width signal duty generator, a multiplier and a rotation speed signal generator. The temperature-controlled voltage duty generator converts temperature-controlled voltage to digital temperature-controlled voltage and executes linear interpolation operation according to a first setting data so as to output temperature-controlled voltage duty signal. The pulse-width signal duty generator coverts pulse-width input signal to a digital pulse-width input signal and executes linear interpolation operation according to a second setting data so as to output a pulse-width duty signal. The temperature-controlled voltage duty signal and the pulse-width duty signal are executed for multiplication by the multiplier so as to output mixing-duty signal.

Abstract: A motor drive circuit includes: an advance angle setting correcting device having a correction reference cycle according to a reference advance angle count value, in which a correction amount is calculated as a ratio of the correction reference cycle to a cycle of a detection signal indicating a detected frequency proportional to a motor rotation speed, and in which an advance angle setting signal is obtained by multiplying the correction amount by a proportionality factor; and an advance angle setting device in which the advance angle correction value is added to the reference advance angle count value thereby outputting an advance angle setting signal, wherein a drive command signal containing a rotation speed information based on a target rotation speed is externally fed, the motor rotation speed is variably controlled in response to the drive command signal, and the detection signal is fed from a rotation speed detecting device.

Abstract: An integrated servo system and a method of controlling a motor is provided. The integrated servo system includes a position detector which determines original position data of a motor and a position signal processor which determines a position of the motor based on the determined position data. The integrated servo system further includes a servo controller circuit which controls the motor based on the determined position data and a parallel bus through which the determined position data is transmitted from the position signal processor to the servo controller circuit.

Abstract: A motor driving system including command value output means configured to output an analog value according to a rotation speed command; a first power line having first switching means; a drive circuit, to which power is supplied via the first switching means and the first power line, driving a motor supplying rotation based on the analog value; and switching control means configured to make the first switching means nonconductive when the analog value is smaller than a first predetermined value, and independent of the command value output means.

Abstract: An apparatus or method which accepts a burst of pulses at a frequency which may not be tightly controlled and converts this into a trajectory command that is a suitable motion profile for an incremental motor control application. The output of the invention can be a pulse stream that can be fed to an existing incremental pulse input motor drive or the invention can be embedded into a motor drive where its output is a numerical sequence that defines a physically realizable trajectory to be fed to the control circuits and software within the motor drive.

Abstract: A system and method for determining a rotor time constant of an AC induction machine is disclosed. During operation of the induction motor, a flux signal is injected into a rotor flux command so as to generate a time-variant rotor flux. A voltage-current flux observer determines amplitudes of rotor flux variations resulting from the time-variant rotor flux, with the amplitudes of the rotor flux variations comprising an amplitude of a rotor flux variation based on a current model of the voltage-current flux observer and an amplitude of a rotor flux variation based on a combined voltage-current model of the voltage-current flux observer. A rotor time constant of the induction motor is then estimated based on the determined amplitudes of the rotor flux variations.

Abstract: In various implementations, a condition of a motor may be monitored based at least partially on time required to achieve a change in speed. A notification may be transmitted based on the condition of the motor.

Abstract: A motor control circuit and associated techniques detect a zero crossing of a current in a motor winding by detecting a reverse current in a half bridge circuit used to drive the motor winding.

Abstract: Method for operating an actuator for maneuvering a windable mobile element of a home automation appliance, the mobile element being able to be displaced between two extreme positions, the method comprising a first step for definition of a first angular speed setpoint of the actuator in a first docking area and a second step for definition of a second angular speed setpoint of the actuator in a second docking area, the first and second angular speed setpoints being different.

Abstract: In one embodiment, a method includes measuring between two consecutive electrical commutations of a brushless direct-current (BLDC) motor a current through the BLDC motor. One or more pulse-width-modulation (PWM)-configurable signals are driving the BLDC motor. The method includes determining a waveform of the current through the BLDC motor; if the waveform of the current through the BLDC motor comprises a first type, then increasing a duty cycle of each of one or more of the PWM-configurable signals driving the BLDC motor; and, if the waveform of the current through the BLDC motor comprises a second type, then decreasing a time interval between electrical communications of the BLDC motor.

Abstract: A method for starting an electric motor having a rotor, comprising the following steps:—driving the rotor with a first torque in a first rotational direction, wherein a maximum value of the first torque is not higher than a maximum countertorque acting counter to the rotation of the rotor, so that the rotor comes to a standstill in a first stationary position;—driving the rotor starting from the first stationary position in a second rotational direction that is counter to the first rotational direction until the rotor comes to a standstill in a predefined second stationary position; and—starting from the rotor in the first rotational direction starting from the second stationary position.

Abstract: A lock state occurrence determination apparatus includes a counter, a reset device, a reference time changing device, a lock state determination device, and an invalidation device. The invalidation device performs, in a case where a false determination of occurrence of a lock state of a motor is caused by the lock state determination device due to an operation input to operate a rotation speed of the motor, at least one of a first invalidation operation to invalidate the lock state determination device and a second invalidation operation to invalidate continuation of a counting operation by the counter.

Abstract: A servo control device includes a follow-up control unit that controls a control target that drives a mechanical system by a motor, a command function unit that has input therein a phase signal ? indicating a phase of a cyclic operation performed by the control target, and that calculates a machine motion command according to the phase signal ? by a preset first function, a second derivative unit that uses a second function obtained by second-order differentiating the first function with respect to the phase signal to calculate a value of the second function according to the phase signal as a second-order differential base signal, a correction-value computation unit that computes a first command correction value for correcting the motor motion command by using a product of a square value of the phase velocity, the second-order differential base signal, and a first constant, and a correction-value addition unit that calculates the motor motion command based on an added value of the first command correction val

Abstract: A system and method for limiting engine starting current of a starter motor of an engine is described. In one example, starter motor current is controlled according to vehicle speed. The method may allow vehicle system voltage to remain at a higher level during automatically initiated engine starts.

Abstract: An inverter device of a rotating electrical machine drives a multiphase rotating electrical machine having the variable number of rotations using a switching element provided for each phase. An example of the inverter device of the rotating electrical machine includes: a frequency setting unit for determining and setting a carrier frequency of a carrier signal for use in driving the switching element for each phase depending on the state of each phase of the rotating electrical machine for each specified electrical angle obtained by equally dividing a cycle of an electrical angle; and a signal generation unit for generating a drive signal for drive of the switching element of each phase using the carrier signal of the carrier frequency set for each phase by the frequency setting unit. The carrier frequency of each phase is an integral multiple of the phase voltage frequency at the specified electrical angle.

Abstract: A motor driving device and a driving method thereof is disclosed herein and comprises a PWM converting circuit, an oscillator, a comparator, a controlling unit. The PWM converting circuit converts an analog signal according to an adjustable the highest setting voltage, an adjustable the lowest setting voltage and a controlling signal. The analog signal and a triangular signal generated by the oscillator are inputted to the comparator to compare to output a drive signal to the controlling unit so as to control the motor speed. The motor driving device in the present invention can adjust the motor rotating speed curve to set the lowest rotating speed of the motor so as to achieve the function of changing the motor rotating speed and maintain the lowest torque of the motor to increase the flexibility of the motor speed control.

Abstract: A control command generator that generates an armature interlinkage flux command and a torque current command by a torque command, a rotation speed, and an operation target command, includes a first flux command generator generating a first flux command by the toque command or the torque current command, a second flux generator generating a second flux command by the torque command or the torque current command and the rotation speed of the synchronous machine, a command allocation setting unit setting an allocation coefficient equivalent to an allocation ratio of the two first and second flux commands by the operation target command, a flux command adjuster outputting an armature interlinkage flux command by the two flux commands and the allocation coefficient, and a torque current command generator generating the torque current command by the torque command and the armature interlinkage flux command.

Abstract: An electric motor control device includes a control section adapted to control supply of a drive current to an electric motor, and a rotational speed detection section adapted to detect a rotational speed of the electric motor, the drive current includes a d-axis current and a q-axis current, and the control section calculates a q-axis current command value based on a torque command value to the electric motor, calculates a d-axis current command value using a difference between the rotational speed of the electric motor and a previously determined base rotational speed of the electric motor, and the q-axis current command value, and performs vector control on the electric motor using the d-axis current command value and the q-axis current command value.

Abstract: The invention relates to a combined method and device for powering and charging, wherein said device comprises an AC motor (6), a converter (2), storage means (5), and switching means (4) either for enabling the powering of the motor (6) or for enabling the charging of the storage means (5) by the converter (2). The switching means (4) is integrated in the converter (2) and includes at least one H-shaped bridge structure (3) for each phase of the motor (6).

Abstract: A system and method are provided for reducing the energy consumed by a pump jack electric motor by reducing the supply voltage to the motor when the motor would be generating energy in open loop mode. By substantially eliminating the energy generation mode, the braking action of the utility grid in limiting the acceleration of the motor and system that would otherwise occur is substantially removed. The motor and system will speed up, allowing the natural kinetic energy of the cyclic motion to perform part of the pumping action. A closed loop controller in electrical connection with the motor computes the necessary information from the observed phase angle between the voltage and current supplied to the motor. By reducing the supply voltage to the motor, the observed phase angle may be reduced to a target phase angle value.

Abstract: Disclosed herein is a motor control apparatus and a method thereof. The operation efficiency of a compressor may be maintained by using a sensorless algorithm, sampling a current applied to a motor more than twice within a period of the triangular carrier wave for performing pulse width modulation to calculate a reference voltage, driving the motor according to the calculated reference voltage to improve control resolution, and performing a high-speed operation while reducing a volume of the compressor, without adding a separate hardware when controlling the operation of the motor provided in the compressor at a high speed.

Abstract: Embodiments of the present invention permit the optimization of torque control of a permanent magnet machine including obtaining instantaneous terminal voltages of the machine, transforming the instantaneous terminal voltages to a zero direct axis voltage and a non-zero quadrature axis voltage, using a mathematical transformation, regulating the electrical frequency of the permanent-magnet machine such that the zero direct-axis voltage is adjusted to have a value of zero, determining a non-final electrical angle of the permanent-magnet machine by applying an integrator to the regulated electrical frequency of the machine, determining a final electrical angle of the of the machine by integrating the non-final electrical angle and an electrical angle from a previous calculation cycle, and regulating the current vector of the machine such that the current vector is perpendicular to the final electrical angle of the machine, thereby optimizing the torque of the machine.

Abstract: A drive unit, which can be included in an image forming apparatus with peripherals disposed thereto and use a control method therefore, includes an inner rotor brushless DC motor, a driver, a rotation detector, and a controller. The driver supplies power to drive the brushless DC motor. The rotation detector detects an amount and direction of rotations of an output shaft. The controller controls the rotations of the brushless DC motor and obtains a target drive signal of the brushless DC motor externally and a detection signal from the rotation detector and outputs a signal to the driver. The controller controls a speed of rotation of the brushless DC motor by varying the signal output to the driver based on the target drive signal and the detection signal.

Abstract: Disclosed is an apparatus for driving a BLDC motor, the apparatus including: a BLDC motor having a single sensing coil therein; a position/speed calculation unit for calculating a current position and a current speed of a rotor by using voltages at both ends of the sensing coil; a control unit for comparing the current speed of the rotor calculated by the position/speed calculation unit with a command speed and then outputting a control signal through a Proportional Integral (PI) control; a motor driving unit for generating a PWM signal based on the current position of the rotor calculated by the position/speed calculation unit and the control signal output by the control unit; and a power device unit for controlling the BLDC motor according to the PWM signal generated by the motor driving unit.

Abstract: A motor drive system comprising: an inverter that supplies power to a three-phase motor; and a control unit that controls switching elements of upper and lower arms included in the inverter by switching between supply control of controlling the switching elements so that alternating current is supplied to three phases of the three-phase motor and suspension control of controlling the switching elements so that the supply of current is stopped. The suspension control involves: putting and keeping, in a conduction state, a switching element of at least one upper arm each corresponding to one of one or more phases through which current flows in a direction entering the three-phase motor at a timing at which the supply of current is stopped, and putting and keeping switching elements of rest of the upper arms and switching elements of lower arms in a non-conduction state.

Abstract: In a motor control unit, a current-carrying failure detection unit determines a first determination condition and a second determination condition. The current-carrying failure detection unit measures a duration of a state where the first determination condition is satisfied, and a duration of a state where the second determination condition is satisfied. When the first or second duration exceeds a predetermined reference period, the current-carrying failure detection unit determines that a current-carrying failure has occurred.

Abstract: A method and apparatus are provided for ripple suppression of brushless DC motors at any given velocity irrespective of the limited bandwidth of the driver/amplifier supplying the excitation currents to the stator. In a preferred embodiment, Fourier coefficients of the current waveform are calculated as a function of rotor velocity by taking into account the driver/amplifier's finite bandwidth dynamics. For a given velocity, Fourier coefficients of the series approximating the waveform (control signal) are calculated as a function of the rotor velocity and the amplifier dynamics, to generate a waveform that results in no torque or velocity pulsations. When changing the motor speed, the coefficients are updated (recalculated) based on the new desired velocity (and amplifier dynamics), resulting in generation of an updated waveform that results in no torque or velocity pulsations at the new motor speed.

Abstract: Described herein is a drive arrangement for the motor-driven adjustment of an adjustable element in a motor vehicle, the drive arrangement having two electrical drives and a control device, the drives, in the fitted state, acting in the same way on the adjustable element and having a substantially identical configuration, apart from tolerance-related discrepancies. The control device has a power controller which, in the fitted state, during the motor-driven adjustment of the adjustable element, subjects the electrical power that is output respectively to the two drives to closed-loop control, for the purpose of compensating for the tolerance-related discrepancies, in such a way that an identical electrical power consumption is established for both drives.

Abstract: Disclosed herein is a motor control apparatus and a method thereof. A phase error of the reference voltage output corresponding to a time delay caused by digital control may be compensated to stably control a motor, thereby improving the stability of a system. The phase compensation unit may be provided therein to convert a reference voltage of the synchronous coordinate system into a reference voltage of the stationary coordinate system when controlling the high-speed operation of the motor, thereby compensating a phase error of the reference voltage output, and allowing the motor to be operated at a high speed while maintaining its efficiency and reducing a volume of the compressor.

Abstract: A system and method are described for conserving energy by decoupling a supply voltage to an electric motor operating under periodic load variations. A time segment value corresponding to a duration of periodic load variations is obtained and the supply voltage is adjusted to maintain an observed phase angle for a supply voltage and current at a value corresponding to a target phase angle. At least one off-time period is identified during the time segment value that corresponds to when the adjusted supply voltage is applied to the motor. During a remainder of the time segment value, at least one turn-on time period is provided when the supply voltage is coupled to the motor. The system may enter to a closed-loop control process after a predetermined period of time to adjust to any changes in the periodic load variations.

Abstract: An electric motor comprising a stator having two coil sets arranged to produce a magnetic field of the motor, each coil set comprising a plurality of coil sub-sets; and two control devices, wherein the first control device is coupled to the plurality of coil sub-sets for the first coil set and the second control device is coupled to the plurality of coil sub-sets for the second coil set and each control device is arranged to control current in the respective plurality of coil sub-sets to generate a magnetic field in each coil sub-set to have a substantially different magnetic phase to the other one or more coil sub-sets in the respective coil set; and wherein the first control device and the second control device are mounted adjacent to the stator.

Abstract: Disclosed is a flux controller for maintaining reliable flux estimation performance in a low velocity region, the controller including a velocity controller, a torque current controller for outputting a torque voltage command, a flux controller for outputting a flux current command, a flux current controller for receiving the flux current command to output a flux voltage command, a three-phase converter for converting the torque voltage command and the flux voltage command into a three-phase voltage command applied to the induction motor to output the three-phase voltage command, a flux estimator for outputting a rotating angle of a rotor of the induction motor, an estimated flux value of the rotor and an estimated velocity of the rotor, and a flux regulator for receiving the torque voltage command and the estimated velocity to output a gain value that regulates a magnitude of the flux command.

Abstract: Provided is a motor control device which realizes automatic adjustment of control of a motor for driving a mechanical load through a simple operation. The motor control device includes: a follow-up control unit (6) for receiving detection information of a detector (3) to output a torque command signal and output a status of motor control of a motor (1) as a control status amount signal, when a command signal regarding the motor control to be output from an upper-level controller is absent; an oscillation detection unit (9) for receiving the control status amount signal and detecting oscillation of a control status amount to output an oscillation detection signal; and an automatic adjustment unit (10) for receiving the oscillation detection signal to monitor a control status of the motor (1) and adjust a control parameter of the follow-up control unit (6) only when abnormality is detected.

Abstract: A power converting apparatus including a power converter that converts a DC voltage into an AC voltage and applies the AC voltage to an AC rotating machine and a control unit that controls the power converter based on an operation command from the outside is provided. The power converting apparatus includes: a first calculating unit that calculates and outputs, from a d-axis current detection value and a q-axis current detection value detected by the AC rotating machine and current command values based on the operation command, first voltage command values to the power converter, magnetic fluxes of the AC rotating machine, and an angular frequency; and a second calculating unit that sets, as an initial value, at least one of the magnetic fluxes and the angular frequency input from the first calculating unit and calculates and outputs second voltage command value to the power converter and an angular frequency.

Abstract: Speed of a motor, generator or alternator, more particularly the speed of an alternating current (AC) induction motor is determined. Problems associated with previous devices are overcome by providing a speed monitoring device that is readily retrofitted to an existing motor. A test signal is superimposed onto an input voltage, which voltage in use is applied to at least one winding of the stator of a motor (the test signal is at a frequency substantially equal to the rotor frequency). The test signal frequency is varied so that it varies from a minimum frequency to a maximum frequency. A current monitor monitors a resultant current, in the at least one stator winding. and deriving from the resultant current is a signal indicative of the rotor frequency.

Abstract: To suppress torque variation including various frequency components, a lot of measuring and adjusting operations are necessary, and this takes much time and trouble. An electronic apparatus includes a selection unit configured to select, on the basis of a threshold value relating to speed variation of the mechanism and threshold values relating to a plurality of frequencies that constitute the speed variation, a frequency to be measured and a frequency to be suppressed, from the plurality of frequencies, a generation unit configured to generate a periodic signal including the frequency to be suppressed that is selected by the selection unit, and an acquisition unit configured to output the periodic signal generated by the generation unit to the control unit and to acquire a parameter relating to the frequency included in the periodic signal.

Abstract: A system and method are provided for reducing the energy consumed by a pump jack electric motor by reducing the supply voltage to the motor when the motor would be generating energy in open loop mode. By substantially eliminating the energy generation mode, the braking action of the utility grid in limiting the acceleration of the motor and system that would otherwise occur is substantially removed. The motor and system will speed up, allowing the natural kinetic energy of the cyclic motion to perform part of the pumping action.

Abstract: A system and method are disclosed for turning off the voltage to a pump jack electric motor during predetermined periods of time to save energy. In the method, the motor's response to closed-loop control may be evaluated over several pump strokes. The periods of the pump stroke when it is feasible to turn off the motor may be identified. The consistency of the measurements over several strokes may be evaluated. The motor may be turned off during predetermined periods on subsequent pump strokes when each pump stroke shows sufficiently similar behavior to that predicted during the closed-loop control process. The system may return to the closed-loop control process after a predetermined period of time to adjust to any changes in the system.

Abstract: The invention relates to a centrifugal pump assembly with an electric drive motor and with a control device having a frequency converter, for the control of the rotational speed of the drive motor, wherein the control device is designed in a manner such that in at least one control region, a field weakening is produced in the drive motor, by way of which the rotational speed of the drive motor is increased.

Abstract: A motor driving circuit may include a Hall sensor configured to generate a Hall signal according to the position of a rotor of a motor to be driven; a Hall bias circuit; an analog amplifier configured to amplify the Hall signal; an A/D converter configured to convert the Hall signal into a digital signal; an amplitude control circuit configured to adjust the amplitude of the digital signal; a control signal generating unit configured to generate a control signal to be used to drive the motor; and a driver circuit configured to drive the motor according to the control signal. The components may be monolithically integrated on a single semiconductor substrate. The amplitude control circuit may include an amplitude correction circuit; and a target amplitude judgment circuit configured to adjust the gain of the analog amplifier.

Abstract: A control console to remotely control medical equipment is disclosed having a base with an ergonomically adjustable pedal system. The base further has an opening to receive the pedal system. The pedal system includes a moveable pedal tray with a pedal base. The tray includes a first left pedal assembly and a first right pedal assembly, and an upper tier having a second left pedal assembly and a second right pedal assembly respectively in alignment with and elevated above the first left pedal assembly and the first right pedal assembly. Rollers are rotatable coupled to the moveable pedal tray to allow it roll over a floor. A drive assembly is coupled between the moveable pedal tray and the base. The drive assembly applies a force to the to roll the moveable pedal tray over the floor within the opening of the base.

Abstract: An inverter includes a voltage command generator generating a voltage command value according to an externally specified voltage value, a PWM signal generator generating a PWM signal according to the voltage command value and frequency command value, and a switching unit generating a three-phase AC power according to the PWM signal. The voltage command generator decreases the voltage command value if the output current increases, to prevent the rotation speed of a prime move from suddenly changing. If the output current exceeds a preset upper current threshold, the voltage command value is clamped at a preset minimum output voltage, thereby securing the minimum output voltage for an increase in the output current.

Abstract: A microcomputer that outputs a pulse signal controlling an ultrasonic motor includes a digital/analog, D/A, conversion set register that stores a D/A conversion set value setting an amplitude value of the pulse signal, a D/A converter that generates the amplitude value based on the D/A conversion set value, a first compare register that stores a first compare register value setting a frequency of the pulse signal, a second compare register that stores a second compare register value setting a duty ratio of the pulse signal, a counter that outputs a count value, a first comparator that compares the first compare register value with the count value to generate a first comparison result signal, and a second comparator that compares the second compare register value with the count value to generate a second comparison result signal.

Abstract: A method of controlling a permanent-magnet motor that includes sequentially exciting and freewheeling a winding of the motor. The method includes varying the angle over which the winding is freewheeled in response to changes in speed of the motor. Additionally, a control system for a permanent-magnet motor, and a product incorporating the control system and motor.

Abstract: A drive system, such as for a fluid jet cutting system, includes a brushless synchronous motor configured to drive movement through a loosely coupled transmission, a sensor configured to sense movement, and a control system configured to drive the brushless synchronous motor responsive to previously measured drive coupling.

Abstract: A vibration-type motor controller controls a driving speed of a vibration-type motor relatively moving a vibrating body in which a vibration is excited by an electromechanical energy conversion element 20 to which a first frequency signal and a second frequency signal having a phase difference are applied, and a contacting body which contacts the vibrating body. The vibration-type motor controller includes a speed controller 1 configured to alternately switch a frequency control which changes frequencies of the first and second frequency signals while fixing the phase difference and a phase difference control which changes the phase difference while fixing the frequency so that at least one of a plurality of frequency controls or a plurality of phase difference controls are included to increase and decrease the driving speed of the vibration-type motor.

Abstract: A system includes a control module that controls a motor based on a first rotor angle and an angle determination module that generates the first rotor angle. An estimator module determines an estimated rotor angle of the motor. A transition module generates a transition signal in response to convergence of the estimator module. The angle determination module initially generates the first rotor angle based on an open loop angle. In response to the transition signal, the angle determination module switches to generating the first rotor angle based on the estimated rotor angle and an offset value. The offset value is based on a difference between the estimated rotor angle and the open loop angle at the time when the transition signal is generated.

Abstract: Systems, methods, and devices are disclosed, including an induction-motor controller having a phase path; a solid-state switch interposed on the phase path; and a controller coupled to the solid-state switch. In certain embodiments, the controller is configured to switch the solid-state switch so that the solid-state switch is conductive during a conduction angle of a cycle of an incoming AC power waveform conveyed by the phase path, calculate the conduction angle based on a generally sinusoidal reference value that has a frequency lower than a frequency of the incoming AC power waveform, and adjust the generally sinusoidal reference value based on a value indicative of flux in a load coupled to the phase path.