System and method for clamp current regulation in field-weakening operation of permanent magnet (PM) machines
First Claim
1. A device to regulate current provided to a permanent magnet (PM) machine responsive to a plurality of phase current signals to produce torque on a shaft comprising:
- a processing and drive circuit responsive to a direct voltage command signal and a quadrature voltage command signal, said processing and drive circuit configured to produce said plurality of phase current signals for input to said permanent magnet machine;
a current regulator including, a command circuit responsive to a torque input command signal configured to produce a direct current command signal and a quadrature current command signal;
a control circuit responsive to the direct and quadrature current command signals configured to produce said direct and quadrature voltage command signals; and
a limiter configured to limit the direct and quadrature voltage command signals to a preselected level.
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Accused Products
Abstract
A device to regulate current produced by a permanent magnet machine responsive to a plurality of phase current signals. The motor produces torque for application on a shaft. A processing and drive circuit responsive to a direct current command signal and a quadrature current command signal produces phase current signals for input to the motor. A command circuit responsive to the phase current signals, an angular position of said shaft, and a voltage input command signal to produce a direct current error signal and a quadrature current error signal. A control circuit responsive to the direct and quadrature current error signals produces the direct voltage signal command and the quadrature voltage signal command. The control circuit has a direct and quadrature proportional gain, integrator and clamp circuits. An algorithm produces limited or clamped voltage modulation index signals to obtain maximum efficiency and maximum torque per ampere in the speed range. The algorithm ensures that the current regulator does not run out of voltage by limiting the voltage vector to the achievable voltage vector range that provides maximum torque per ampere and maximum efficiency.
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Citations
18 Claims
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1. A device to regulate current provided to a permanent magnet (PM) machine responsive to a plurality of phase current signals to produce torque on a shaft comprising:
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a processing and drive circuit responsive to a direct voltage command signal and a quadrature voltage command signal, said processing and drive circuit configured to produce said plurality of phase current signals for input to said permanent magnet machine;
a current regulator including, a command circuit responsive to a torque input command signal configured to produce a direct current command signal and a quadrature current command signal;
a control circuit responsive to the direct and quadrature current command signals configured to produce said direct and quadrature voltage command signals; and
a limiter configured to limit the direct and quadrature voltage command signals to a preselected level. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15)
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16. A method for regulating current provided to a permanent magnet (PM) machine that is responsive to a plurality of phase current signals to produce torque on a shaft, said method comprising the steps of:
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providing a processing and drive circuit responsive to a direct voltage command signal and a quadrature voltage command signal, said processing and drive circuit configured to produce said plurality of phase current signals for input to said permanent magnet machine;
providing a current regulator including (i) a command circuit responsive to a current input command signal configured to produce a direct current command signal and a quadrature current command signal, and (ii) a control circuit responsive to the direct and quadrature current command signals configured to produce said direct and quadrature voltage command signals; and
clamping the output of the current regulator so as to prevent the current regulator from exceeding its output voltage limit to thereby maintain control of said machine. - View Dependent Claims (17, 18)
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Specification