Abstract: A regenerative braking controller for an AC motor. To determine an electromagnetic torque for slowing or stopping the motor, the regenerative braking controller accesses a lookup table to retrieve a braking torque value corresponding to a current estimate of rotor velocity. The retrieved braking torque may correspond to a maximum or minimum torque level at which regenerative braking will occur at the current rotor velocity, or to a torque level at which charging current during regenerative braking will be maximized. If an external mechanical brake is present, the regenerative braking controller can forward an external braking torque signal to a controller so that the mechanical brake can apply the remainder of the braking force beyond that indicated by the regenerative braking torque. A method for establishing the braking torques to be stored in the lookup table is also disclosed.

Abstract: A regenerative braking controller for an AC motor. To determine an electromagnetic torque for slowing or stopping the motor, the regenerative braking controller accesses a lookup table to retrieve a braking torque value corresponding to a current estimate of rotor velocity. The retrieved braking torque may correspond to a maximum or minimum torque level at which regenerative braking will occur at the current rotor velocity, or to a torque level at which charging current during regenerative braking will be maximized. If an external mechanical brake is present, the regenerative braking controller can forward an external braking torque signal to a controller so that the mechanical brake can apply the remainder of the braking force beyond that indicated by the regenerative braking torque. A method for establishing the braking torques to be stored in the lookup table is also disclosed.

Abstract: A signal generator has a generator output. The signal generator is configured to generate first and second signals at the generator output. The first signal has a first frequency, and the second signal has a second frequency. Switching circuitry has a circuitry input and a circuitry output. The circuitry input is coupled to the generator output. The circuitry output is adapted to be coupled to an ultrasonic transducer mechanically coupled with a surface. The switching circuitry is configured to: provide the first signal to the ultrasonic transducer at the first frequency to reduce a fluid droplet on the surface from a first size to a second size; and provide the second signal to the ultrasonic transducer at the second frequency to reduce the fluid droplet from the second size to a third size.

Abstract: A circuit comprises a driver circuit, a processing circuit, and a control circuit. The driver circuit has a first frequency control input and a driver output. The processing circuit has a sense input, a second frequency control input, and a parameter output. And the control circuit has a first frequency control output and a second frequency control output, the first frequency control output coupled to the first frequency control input, and the second frequency control output coupled to the second frequency control input.

Abstract: For surface wetting control, an apparatus can expel fluid from a droplet on a surface using a transducer mechanically coupled to the surface. A first area of the surface can have a first wettability for the fluid, and a second area of the surface can have a second wettability for the fluid. The first wettability of the first area of the surface can be greater than the second wettability of the second area of the surface. The first area and the second area can have a patterned arrangement.

Abstract: Disclosed examples include heart rate monitor systems and methods to estimate a patient heart rate or rate of another pulsed signal, in which rate hypotheses or states, are identified for a current time window according to digital sample values of the pulsed signal for a current sample time window, and a rate change value is computed for potential rate transitions between states of the current and previous time windows. Transition pair branch metric values are computed as a function of the rate change value and a frequency domain amplitude of the corresponding rate hypothesis for the current time window, and the pulsed signal rate estimate is determined according to a maximum path metric computed according to the branch metric value and a corresponding path metric value for the previous time window.

Abstract: A circuit configured to: generate a reference clock signal; generate an excitation signal at a target frequency having a period that is a first integer number of cycles of the reference clock signal; update a driver circuit at an update frequency having a period that is a second integer number of cycles of the reference clock signal; digitize sense signals resulting from the excitation signal at a frequency having a period that is a third integer number of cycles of the reference clock signal; identify a fourth integer number of sense signal samples; optionally utilize an excitation control signal having a period that is a fifth integer number of cycles of the reference clock signal; and minimize harmonics at the target frequency of the excitation signal based on the first integer number, the second integer number, the third integer number, the fourth integer number, and possibly the fifth integer number.

Abstract: In described examples of methods and control systems to control a position and/or velocity of a machine, control circuitry is coupled to receive and dither a control signal, and to compute a control output value according to the dithered control signal and a control function. An inverter is coupled to the control circuitry, to control the position and/or velocity according to the control output value.

Abstract: A method includes transforming a signal from a first domain representation to a second domain representation, the signal representing a parameter of a device and having multiple cycles. The method further comprises determining the second domain representation of a droop component of the parameter based on the signal, in which the droop component represents a rate of change of the parameter across one or more cycles of the multiple cycles. The method further comprises generating an adjusted parameter of the device based on combining the respective second domain representations of the parameter and the droop component.

Abstract: A method includes determining a droop component of a measured parameter of a device under test (DUT). The measured parameter is responsive to an excitation signal having a frequency component, and the droop component is determined responsive to a first value of the parameter at a first time and a second value of the parameter at a second time. The parameter at the first time has a first phase value, and the parameter at the second time has a second phase value. The first phase value is equal to the second phase value. The method also includes correcting a frequency domain representation of the parameter by applying the droop component at a frequency of the representation of the parameter corresponding to the frequency component of the excitation signal.

Abstract: Systems and methods for sensorless trapezoidal control of brushless DC motors provide effective high-torque startup and low speed operation without the use of Hall effect sensors or encoders during motor operation. The systems and methods also provide the ability to boost signal-to-noise ratio for motor startup and low speed operation via an augmenting supply voltage. Sampling architectures and current-dependent inductance modeling architectures for the control systems are also described.

Abstract: An apparatus includes a mass detection circuit coupled to a surface covered with a plurality of electrodes. The mass detection circuit is configured to detect a mass of a first droplet present on the surface. The apparatus further includes a transducer circuit coupled to a transducer, which is coupled to the surface and form a lens unit. The transducer circuit configured to excite a first vibration of the surface at a resonant frequency to form a high displacement region on the surface. The apparatus also includes a voltage excitation circuit coupled to the plurality of electrodes. In response to the detection of the mass of the first droplet, the voltage excitation circuit is configured to apply a sequence of differential voltages on one or more consecutive electrodes which moves the first droplet to the high displacement region.

Abstract: From a current measurement circuit, digital samples are received of a current signal that flows through a battery cell within a measurement period. From a voltage measurement circuit, digital samples are received of a voltage signal across the battery cell within the measurement period. First voltage spectral components are generated based on performing a first transform operation on the digital samples of the voltage signal. A current spectrum is generated based on performing a second transform operation on the digital samples of the current signal. Second voltage spectral components are generated based on a first condition of the battery cell before the measurement period and a second condition of the battery cell after the measurement period. A voltage spectrum is including the first voltage spectrum and the second voltage spectrum is generated. An impedance spectrum of the battery cell is generated based on the voltage spectrum and the current spectrum.

Abstract: Methods and apparatus for electrostatic control of expelled material for lens cleaners are disclosed. In certain described examples, an apparatus can expel fluid by atomization from a central area of the surface using an ultrasonic transducer mechanically coupled to the surface. A first electrode can be arranged relative to the central area of the surface. A second electrode can be located in a peripheral area relative to the central area of the surface, in which a voltage can be applied between the first and second electrodes to attract atomized fluid at the peripheral area.

Abstract: A regenerative braking controller for an AC motor. To determine an electromagnetic torque for slowing or stopping the motor, the regenerative braking controller accesses a lookup table to retrieve a braking torque value corresponding to a current estimate of rotor velocity. The retrieved braking torque may correspond to a maximum or minimum torque level at which regenerative braking will occur at the current rotor velocity, or to a torque level at which charging current during regenerative braking will be maximized. If an external mechanical brake is present, the regenerative braking controller can forward an external braking torque signal to a controller so that the mechanical brake can apply the remainder of the braking force beyond that indicated by the regenerative braking torque. A method for establishing the braking torques to be stored in the lookup table is also disclosed.

Abstract: From a current measurement circuit, digital samples are received of a current signal that flows through a battery cell within a measurement period. From a voltage measurement circuit, digital samples are received of a voltage signal across the battery cell within the measurement period. First voltage spectral components are generated based on performing a first transform operation on the digital samples of the voltage signal. A current spectrum is generated based on performing a second transform operation on the digital samples of the current signal. Second voltage spectral components are generated based on a first condition of the battery cell before the measurement period and a second condition of the battery cell after the measurement period. A voltage spectrum is including the first voltage spectrum and the second voltage spectrum is generated. An impedance spectrum of the battery cell is generated based on the voltage spectrum and the current spectrum.

Abstract: In an example, a system includes an ultrasonic transducer and a bracket coupled to the ultrasonic transducer. The system also includes a lens coupled to the bracket. The system includes a control circuit coupled to the ultrasonic transducer and configured to excite the ultrasonic transducer with a signal to clean the lens.

Abstract: A lens structure system with a lens structure and a multi-segmented transducer coupled to the lens structure. Each segment in the plurality of segments has a first conductor and a second conductor, wherein the first conductor and the second conductor are electrically coupled to the segment. The system also has circuitry for applying a voltage to selected segments in the plurality of segments with standing wave signals and traveling wave signals.

Abstract: A method of determining angular position (?) of a rotor of an N-phase permanent magnet motor (PMM). A processor having an associated stored angular position determination (APD) algorithm is programmed to implement the algorithm to cause an associated motor controller to execute steps including forcing one vector at a time a phase vector set of current or voltage vectors to stator terminals of windings for the N-phases a positive and negative magnitude vector, wherein the vector magnitude is sufficiently small to not move the rotor, and a time duration for the forcing current or voltage vectors is essentially constant. The resulting stator current or voltage levels are measured for each current or voltage vector. An N-dimension current vector or voltage vector is generated from superposition of the resulting stator current levels or resulting stator voltage levels. The N-dimension current vector or voltage vector is used to determine angular position.

Abstract: An adaptive torque disturbance cancellation method and motor control system for rotating a load are described. The system has: (i) a speed controller for receiving a first input signal indicating a desired motor speed and, in response, for outputting a motor control signal; (ii) current sensing circuitry for sensing current through a motor that rotates in response to the speed controller; (iii) circuitry for storing, into a storage device, history data representative of the current through a motor when the motor operates to rotate the load; and (iv) circuitry for modifying the motor control signal in response to the history data.