Motor controls, refrigeration systems and methods of motor operation and control

A control system for a brushless motor for energization from a voltage source for the motor, the motor having a stator with windings and a rotor mounted for rotation relative to the stator, comprising:

• a circuit for generating an input signal corresponding to the presence of the rotor at one of a plurality of predetermined rotary positions with respect to the stator;
• electrically controllable switches connected to the windings to control the flow of current therethrough;
• an electronic control responsive to the input signal for controlling in a closed loop running mode the switches to commutate the windings of the motor after receipt of the input signal, said electronic control also being responsive to the speed of the motor, and operative to start the motor in a starting mode by controlling the switches to commutate the windings at an increasing rate, and then to shift commutation to the running mode once the motor reaches a predetermined speed, said electronic control being operative to determine the commutation rate as a function of the voltage applied to the motor.

A control system for an electronically commutated motor adapted to be energized from a source of voltage and including a stationary assembly having a plurality of winding stages adapted to be electronically commutated in at least one preselected sequence, and a rotatable assembly associated in selective magnetic coupling relation with the winding stages, the control system comprising:

• an electronic commutation circuit including switches responsive to control signals and operable generally for electronic commutation of at least some of the winding stages of the electronically commutated motor by applying the voltage thereto in the at least one preselected sequence to effect the energization of the electronically commutated motor and the rotation of the rotatable assembly;
• and
• a circuit for generating control signals for said electronic commutation circuit, said circuit for generating variably establishing a time interval between commutations as a decreasing function of the voltage applied to the motor, for repeatedly producing in a start mode the control signals for said electronic commutation circuit at the interval variably established, and for shifting commutation to a running mode once the time interval decreases to a predetermined amount.

A brushless motor system for energization from a voltage source, comprising a brushless electric motor having a stationary assembly with a plurality of windings adapted to be energized through electronic commutation in at least one preselected sequence, and a rotor in selective magnetic coupling relation with said windings;

• at least one circuit element that generates a position signal corresponding to the presence of said rotor in at least one predetermined rotary position with respect to said stationary assembly;
• switches connected to said windings to control the flow of current therethrough;
• and an electronic control responsive to said position signal for controlling said motor in a closed loop running mode with said switches to commutate said winding in response to said position signal, said electronic control also being responsive to the speed of said motor and operative to provide a starting mode to start Said motor by controlling said switches to commutate said windings at an increasing rate and shifting said commutation from said starting mode to said running mode when said motor reaches a predetermined speed, said electronic control being operative to determine the commutation rate as a function of the voltage applied to said motor.