Hard drive spindle motor controller with soft commutation
First Claim
1. A motor controller for an electric motor having a plurality of motor terminals, the motor controller comprising:
- a commutation control connected to the motor terminals for causing current pulses to flow through one of the terminals during each commutation state;
a current sensor for providing a sense signal representative of the current pulses;
a peak current target circuit for providing a target signal;
a pulse width control for controlling pulse width of the current pulses as a function of the sense signal and the target signal; and
a soft commutation control for adjusting the target signal as a function of commutation state change.
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Accused Products
Abstract
A pulse width modulation controller for a hard disc drive spindle motor controls the rapid spin up of the spindle motor from a stop condition to normal operating speed using a multi-level peak current limiting and six state commutation. At the beginning of each commutation state, peak motor current is limited to less than its steady state peak value for a selected number of pulses. The peak current target then returns its normal level for the remainder of the commutation state. By reducing the peak current target for several pulses after each commutation state change, the effective supply current spike at commutation is reduced or eliminated.
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Citations
19 Claims
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1. A motor controller for an electric motor having a plurality of motor terminals, the motor controller comprising:
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a commutation control connected to the motor terminals for causing current pulses to flow through one of the terminals during each commutation state;
a current sensor for providing a sense signal representative of the current pulses;
a peak current target circuit for providing a target signal;
a pulse width control for controlling pulse width of the current pulses as a function of the sense signal and the target signal; and
a soft commutation control for adjusting the target signal as a function of commutation state change. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A motor controller for an electric motor in which motor speed is controlled by commutation in which motor current pulses are peak current limited, the motor controlling including:
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a circuit for adjusting the peak current of a predetermined number of the motor current pulses as a function of commutation state change, wherein the circuit comprises;
means for providing a target signal as a function of a current command signal and a control signal;
means for providing a sense signal representative of sensed motor current; and
means for controlling pulse width of current pulses to the electric motor as a function of the target signal and the sense signal. - View Dependent Claims (10)
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11. A motor controller for controlling speed of an electric motor having a plurality of terminals, the motor controller comprising:
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a plurality of motor drivers connected to the plurality of the terminals;
sequencer logic for providing control signals to the motor drivers to cause current pulses to flow through one of the terminals during each commutation state, the sequencer logic providing a soft commutation signal as a function of commutation state change;
a current sensor for providing a sense signal representative of the current pulses;
a peak current target circuit for providing a target signal which is a function of a current command signal and the soft commutation signal; and
a pulse width control for controlling pulse width of the current pulses as a function of the sense signal and the target signal. - View Dependent Claims (12, 13, 14, 15, 16)
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17. A method for controlling an electric motor having a plurality of motor terminals, the method comprising:
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producing current pulses as a function of a target value and sensed motor current;
providing current pulses to one of the motor terminals during a commutation state;
changing the commutation state; and
adjusting the target value as a function of commutation state change. - View Dependent Claims (18, 19)
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Specification