Abstract: Systems and methods of quasi-resonant induction heating are provided. In particular, an induction heating system having a quasi-resonant topology can have a quasi-resonant inverter. The inverter can include an induction heating coil configured to inductively head a load with a magnetic field, and a power supply circuit configured to supply a power signal to the induction heating coil. The inverter can further include a first switching element and a second switching element coupled in parallel with the first switching element. The inverter can further include a resonant capacitor coupled in parallel with the induction heating coil. The inverter can further include one or more control devices configured to control operation of the first and second switching elements to regulate an amount of current provided to the induction coil based at least in part on a desired operating frequency associated with the quasi-resonant inverter.

Abstract: A cooktop appliance and method of operation is provided. The cooktop appliance may include a user interface, a power source, a burner, a thyristor, and a relay switch. The power source may be operably connected to the user interface. The burner may include a first radiant heat element and a second radiant heat element electrically coupled in parallel to the power source. The thyristor may be operably connected to the user interface and electrically coupled in series between the power source and the first radiant heat element to control activation of the first radiant heat element. The relay switch may be operably connected to the user interface and electrically coupled in series between the power source and the second radiant heat element to control activation of the second radiant heat element.

Abstract: Methods and systems are provided for monitoring current flow in an induction motor, particularly an induction motor associated with a washing machine and for controlling operation of the motor to limit thermals during operation of the motor. The subject matter provides for periodically stopping the motor and applying a phase limited alternating (AC) voltage to the motor that is of insufficient magnitude to start the motor rotating. A current reading is taken and converted using a look up table to a corresponding temperature. If the temperature exceeds a predetermined amount, temperature fold back procedures are initiated the may include shortening and/or pausing certain washer operations.

Abstract: A cooktop appliance and method of operation is provided. The cooktop appliance may include a user interface, a power source, a burner, a thyristor, and a relay switch. The power source may be operably connected to the user interface. The burner may include a first radiant heat element and a second radiant heat element electrically coupled in parallel to the power source. The thyristor may be operably connected to the user interface and electrically coupled in series between the power source and the first radiant heat element to control activation of the first radiant heat element. The relay switch may be operably connected to the user interface and electrically coupled in series between the power source and the second radiant heat element to control activation of the second radiant heat element.

Abstract: Systems and methods of quasi-resonant induction heating are provided. In particular, an induction heating system having a quasi-resonant topology can have a quasi-resonant inverter. The inverter can include an induction heating coil configured to inductively head a load with a magnetic field, and a power supply circuit configured to supply a power signal to the induction heating coil. The inverter can further include a first switching element and a second switching element coupled in parallel with the first switching element. The inverter can further include a resonant capacitor coupled in parallel with the induction heating coil. The inverter can further include one or more control devices configured to control operation of the first and second switching elements to regulate an amount of current provided to the induction coil based at least in part on a desired operating frequency associated with the quasi-resonant inverter.

Abstract: Methods and systems are provided for monitoring current flow in an induction motor, particularly an induction motor associated with a washing machine and for controlling operation of the motor to limit thermals during operation of the motor. The subject matter provides for periodically stopping the motor and applying a phase limited alternating (AC) voltage to the motor that is of insufficient magnitude to start the motor rotating. A current reading is taken and converted using a look up table to a corresponding temperature. If the temperature exceeds a predetermined amount, temperature fold back procedures are initiated the may include shortening and/or pausing certain washer operations.

Abstract: Systems and methods for safely powering an appliance user interface without external power are provided. One exemplary method includes receiving power generated by rotation of a rotor. The method further includes monitoring for the presence of a safety condition and disabling passive braking of the rotor when the safety condition is present such that the user interface of an appliance is powered. An exemplary washing machine can include a basket and a motor which includes a rotor, the motor being configured to rotate the basket by rotating the rotor. The washing machine can further include a user interface and a motor control circuit configured to drive the motor. The motor control circuit can be further configured to receive power generated by rotation of the rotor, monitor for the presence of a safety condition, and disable passive braking of the rotor when the safety condition is present.

Abstract: Systems and methods for safely powering an appliance user interface without external power are provided. One exemplary method includes receiving power generated by rotation of a rotor. The method further includes monitoring for the presence of a safety condition and disabling passive braking of the rotor when the safety condition is present such that the user interface of an appliance is powered. An exemplary washing machine can include a basket and a motor which includes a rotor, the motor being configured to rotate the basket by rotating the rotor. The washing machine can further include a user interface and a motor control circuit configured to drive the motor. The motor control circuit can be further configured to receive power generated by rotation of the rotor, monitor for the presence of a safety condition, and disable passive braking of the rotor when the safety condition is present.

Abstract: A system and method for controlling refrigeration including a temperature sensor operable to measure a temperature from a refrigeration case and a transceiver in communication with the temperature sensor and operable to wirelessly transmit data. A repeater receives the wirelessly transmitted data and further wirelessly transmits the data to a receiver. A controller in communication with the receiver controls the refrigeration system based upon the wirelessly transmitted data from the refrigeration case. The refrigeration case also includes a mode switch for suspending temperature reading and control for a period of time. For example, the mode switch can be used by an operator during cleaning or maintenance of the refrigerator case. Temperature control algorithms are used by the controller, and include: dead-band range (DB), proportional/integral (PI), proportional/integral/differentiation (PID) and fuzzy-logic (FL).