Patent ID: 6462504
Filing Date: 2002-10-08
Classification: H02P

Abstract:
An energization control device for electric motors comprising:a plurality of phase coils arranged on a stator, one end of each of the phase coils being connected to one of high and low potential lines of a power supply by way of a first switching element, the other end of each of the phase coils being connected to the other of the high and low potential lines of the power supply by way of a second switching element, one end of the each of the phase coils being connected to the other of the high and low potential lines of the power supply by way of a first diode which allows current flow from the latter to the former, the other end of each of the phase coils being connected to one of the high and low potential lines of the power supply by way of a second diode which allows current flow from the former to the latter; angular position detection means for detecting an angular position of the rotor; rotational speed detection means for detecting a rotational speed of the rotor; actual current detection means for detecting an actual current which passes through each of the phase coils; and control means determining an energization-on angle, a first energization-off angle and a target current value, for each of the phase coils, on the basis of the rotational speed of the rotor and a target torque which is calculated based on an external information inputted, the control means making one of the first and second switching elements ON-OFF and the other ON while the rotor rotates from the energization-on angle to the first energization-off angle, and approximating the actual current value to the target current value, the control means determining a second energization-off angle on the basis of the target torque and the rotational speed of the rotor for each of the phase coils, the control means making both the first and second switching elements OFF concurrently while the rotor rotates from the second energization-off angle to the energization-on angle, the control means making one of the first and second switching elements ON-OFF at an arbitrary duty ratio and making the other OFF while the rotor moves from the first energization-off angle to the second energization-off angle.