초록 ▼

A controller for a switched reluctance motor that does not utilize a sensor for detecting the rotational position of the rotor. The inductance of each field winding changes according to the rotational position of the rotor. The rotational position of the rotor of the motor is determined by measuring

A controller for a switched reluctance motor that does not utilize a sensor for detecting the rotational position of the rotor. The inductance of each field winding changes according to the rotational position of the rotor. The rotational position of the rotor of the motor is determined by measuring the inductance of each phase during periods when a minimum level of inductance for the phase is expected to occur. A series of voltage pulses are applied to the appropriate field winding during the appropriate period while the current produced in response to the voltage pulses is measured. The relationship between applied voltage, measured current, and time, is utilized to determine the inductance value as it decreases and then increases between positions of rotor alignment. Commutation to a next phase is performed based upon the measured inductance values. More particularly, a first voltage pulse is applied to an appropriate field winding after a commutation and a level of current induced by the voltage pulse is stored across a capacitor. Then, subsequent current levels produced by subsequent voltage pulses are compared to a predetermined threshold. The predetermined threshold ensures that the rotor is not stationary during the measurements. Once a current level exceeds the predetermined threshold, subsequent current levels are compared to the stored level. Upon a subsequent measured value which does not exceed the stored value, commutation to a next phase is performed. The number of degrees of rotation between removing the excitation voltage from a phase and alignment of the rotor with the corresponding phase is the phase advance. The phase advance is adjusted by controlling an offset value utilized for comparing the current levels to the stored value.

대표청구항 ▼

[ What is claimed is:] [1.] A method of sensing a position of a rotor of a switched reluctance method and for appropriately commutating the motor in response to the position of the rotor, the method comprising:a) applying a first voltage pulse to a first phase of the motor;b) storing a value represe

[ What is claimed is:] [1.] A method of sensing a position of a rotor of a switched reluctance method and for appropriately commutating the motor in response to the position of the rotor, the method comprising:a) applying a first voltage pulse to a first phase of the motor;b) storing a value representative of a current produced in response to the first voltage pulse thereby forming a stored value;c) after the step of storing, applying a series of one or more additional voltage pulses to the first phase of the motor for producing a series of values representative of corresponding current pulses;d) comparing each of the series of values to the stored value; ande) after one of the series of values is below the stored value by at least an offset, providing a commutation signal.