Apparatus and method for controlling permanent magnet electric machines
First Claim
1. A control for use with a permanent magnet machine, comprising:
- an algorithm determining an open-loop magnetizing reference current;
a feedback path generating a feedback term based on the rotor speed of the permanent magnet machine and a torque current error; and
a subtractor for subtracting the feedback term from the open-loop magnetizing reference current to generate a total magnetizing reference current.
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Accused Products
Abstract
A control scheme for an surface-mounted permanent-magnet synchronous (SMPMS) drive uses a combination of an open-loop magnetizing current reference calculation and a stabilizing feedback term, which speeds-up the torque transient response. The feedback term increases the stability margin during torque transients by increasing the available voltage margin for current control. The magnetizing current reference calculation takes into account the saturation effects in the SMPMS drive, which occur at peak torque points, and compensates for them. By taking into account saturation effects, stable operation at high speed is achieved, thereby increasing the speed range of the SMPMS drive.
8 Citations
18 Claims
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1. A control for use with a permanent magnet machine, comprising:
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an algorithm determining an open-loop magnetizing reference current;
a feedback path generating a feedback term based on the rotor speed of the permanent magnet machine and a torque current error; and
a subtractor for subtracting the feedback term from the open-loop magnetizing reference current to generate a total magnetizing reference current. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. A method of generating a reference current for controlling a permanent magnet machine, comprising:
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determining an open-loop magnetizing reference current;
generating a feedback term based on the rotor speed of the permanent magnet machine and a torque current error; and
subtracting the feedback term from the open-loop magnetizing reference current to generate the reference current. - View Dependent Claims (9, 10, 11, 12, 15, 16, 17, 18)
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13. A computer-usable medium storing a software program comprising:
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means for determining an open-loop magnetizing reference current for a permanent magnet machine;
means for generating a feedback term based on the rotor speed of the permanent magnet machine and a torque current error; and
means for subtracting the feedback term from the open-loop magnetizing reference current to generate a total magnetizing reference current.
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14. A controller, comprising:
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a first software routine for determining a magnetizing reference current and a torque reference current based on one or more inductance saturation curves at peak torque points for a permanent magnet motor;
a second software routine for computing an output magnetizing reference current by subtracting from the magnetizing reference current a feedback term based on the rotor speed of the permanent magnet motor and a torque current error, the torque current error being the difference between the torque reference current and a feedback torque current from the permanent magnet motor; and
a processor for executing the first and second software routines.
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Specification