Nidec Motor Corporation

Emerson Electric Company

Digital Appliance Controls, Inc.

Thomas J Sheahan

Darko Marcetic

Gregory A Peterson

Michael P Sullivan

A system and method for dynamically optimizing flux levels in electric motors based on estimated torque. Motor parameters and motor equations are used to estimate operating characteristics and to set current and voltage limits which define an optimal flux operating range for a given speed and torque of the motor. A slope of a linear flux gain is determined within the defined operating range at different speeds of the motor. The determined slopes for the different speeds are saved in a memory element. A control element determines and achieves an optimal flux level for the motor by accessing the table to identify a specific slope which corresponds to an actual speed of the motor, multiplying the slope by the estimated torque and adding an offset value to determine a phase current component value associated with the optimal flux level, and applying the determined phase current component value to the motor.

System and method for optimizing flux regulation in electric motors

A motor controller for an electric motor having a stator and a rotor. The motor controller includes a power input for receiving AC power from a power source; a control input for receiving a control signal from a control; and circuitry for switching power from the power source to the electric motor in response to the control signal. The circuitry is operable to: apply a driving waveform to the stator to cause rotation of the rotor; remove the driving waveform from the stator to cause the rotor to coast and eventually stop; apply a stop detection waveform to the stator while the rotor is coasting, wherein the stop detection waveform induces a waveform on the rotor which in turn induces a waveform back to the stator while the rotor is rotating; and monitor the stator to detect a characteristic of the waveform induced back to the stator to detect when the rotor has substantially stopped rotating.

Systems, methods, and assemblies for detecting stoppage of electric motors

A motor controller for an electric motor having a stator and a rotor. The motor controller includes a power input for receiving AC power from a power source; a control input for receiving a control signal from a control; and circuitry for switching power from the power source to the electric motor in response to the control signal. The circuitry is operable to: apply a braking waveform to the stator while the rotor is rotating; monitor a reactive power of the stator; detect an increase in the reactive power of the stator to determine the rotor has substantially stopped rotating; and remove the braking waveform from the stator in response to detecting the increase in the reactive power.

Systems and methods for braking an electric motor

A method of operating a washing machine to detect unbalanced loads has been developed. The method includes operating a motor to rotate a tub holding a load at a first rotational rate that is below a threshold rotational rate, identifying a mass of the load, operating the motor to rotate the tub at a second rotational rate that is above the threshold rotational rate, identifying a power applied to the motor to continue rotation of the tub at the second rotational rate, obtaining an out of balance mass value from a memory with reference to the power applied to the motor, second rotational rate, and identified mass, identifying a maximum rate for the tub with reference to the out of balance mass value, and operating the motor to rotate the tub at a rate that is less than or equal to the maximum rate.

Washing machine out of balance detection

A method enables adjustment of a current sense voltage for accurate measurement of an operating temperature for an electrical motor. The method includes identifying a DC input voltage to a motor winding and a duty cycle corresponding to the DC input voltage, the duty cycle being identified with reference to a linear relationship between two inverter loss factors established for different DC input voltages within a range of voltages for the DC input voltage. A voltage across the motor winding is identified with reference to the identified duty cycle, the identified voltage not including voltage dropped across an inverter used to apply the DC input voltage to the motor winding. The identified voltage across the motor winding is used to identify a resistance change for the motor winding.

Method for calibrating a motor control circuit to improve temperature measurement in an electrical motor

A method enables measurement of an inverter loss within a motor control circuit for an appliance. The method includes applying a constant DC current generated from a first AC supply voltage to a motor winding through an inverter at a first duty cycle, measuring a first voltage corresponding to the current through the motor at a motor current sense resistor, computing a first ratio of the first measured voltage at the motor current sense resistor to a first DC input voltage corresponding to the first AC supply voltage, identifying a second duty cycle from the first computed ratio, comparing the second duty cycle to the first duty cycle, and identifying a first inverter loss factor from the difference between the first duty cycle and the second duty cycle.

Method for calibrating a motor control circuit to improve temperature measurement in a electrical motor

Method and system for calibrating a motor control circuit to improve temperature measurement in an electrical motor

The invention is a communication management module for effectively controlling an optical interface that uses a control panel indicator in an appliance for communication. The module includes a physical, framing, transport, dispatch, and application layers. The module is implemented to verify the integrity of data frames and to correlate data frames and responses with applications in the application layer.

System and method for communicating with an appliance through an optical interface using a control panel indicator

Generally there is provided circuitry and a method for frequency multiplication of a first signal source including a first counter for counting pulses from a second signal of higher frequency by counting from a loaded value and generating a circuit output each time the first counter resets. A second counter is used to count cycles of the first counter and generate a feedback signal when a predetermined number of cycles have been completed (the system multiplication factor). Calibration is achieved by comparing the end of the period of the first signal to the occurrence of a feedback signal. In response the comparision circuit causes the loaded value to be changed to thereby control the output.

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Cary, IL, United States of America

Thomas J Sheahan