A Direct Torque Control Method for Permanent Magnet Synchronous Generator

Abstract

The invention provides a direct torque control method for a permanent magnet synchronous generator. The direct torque control method comprises the steps that a nonlinear mathematical model of the permanent magnet synchronous generator in a coordinate system is built; a PI controller of a rotational speed control ring is designed, operation is conducted on a rotational speed instruction value and an actual measurement rotational speed value through the PI controller, and an instruction value of inner ring electromagnetic torque is obtained; a state equation with stator flux linkage amplitude and electromagnetic torque amplitude of the permanent magnet synchronous generator serving as state variables is built; a permanent magnet synchronous generator inverse system expression of a permanent magnet synchronous generator original system is worked out; a new pseudo-linear system is built; an equivalent linear subsystem of the pseudo-linear system is worked out; a sliding mode variable structure control law of the equivalent linear subsystem is designed through a variable exponent reaching law; the sliding mode variable structure control law is substituted into the inverse system expression, and a controlled quantity of the original system is obtained through inverse solution. According to the direct torque control method for the permanent magnet synchronous generator, linear decoupling control over the electromagnetic torque amplitude and the stator flux linkage amplitude in direct torque control of the permanent magnet synchronous generator is realized, and robustness of a whole system is high.

Description

technical field [0001] The invention relates to a direct torque control method of a permanent magnet synchronous generator, which belongs to the technical field of permanent magnet synchronous motors. Background technique [0002] The direct torque control method is a new AC motor control method following the vector control method. It takes the electromagnetic torque and stator flux linkage as the control objects, and omits the complicated rotation coordinate transformation in the vector control method, making it relatively Vector control is easier. [0003] The traditional permanent magnet synchronous generator (PMSG) direct torque control regards the inverter and the permanent magnet synchronous motor as a whole, and uses a double hysteresis loop control method to compare the electromagnetic torque and the stator flux linkage amplitude The error between the same reference value, and according to the comparison result, the optimal voltage vector is used to realize the simu...

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Problems solved by technology

However, since the mathematical model of the permanent magnet synchronous generator is a multivariable, nonlinear, and strongly coupled system, the electromagnetic torque and the amplitude of the stator flux linkage are coupled with each other, and the traditional direct torque control method will lead to electromagnetic torque, Stator flux amplitude pulsation is large, and the stable operation performance of the motor is poor

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