Direct torque control system without flux linkage loop

Abstract

The invention discloses a direct torque control system without a flux linkage loop. The direct torque control system comprises a motor and a control system. The control system comprises a coordinate transformation module for detecting three-phase currents ia, ib and ic and three-phase voltages ua, ub and uc at an output end of a three-phase inverter module and converting the currents and voltagesinto i[alpha] and i[beta], and u[alpha] and u[beta]; a torque and rotor position estimation module for estimating stator flux linkages [psi][alpha] and [psi][beta] and a rotor position [theta]r in accordance with i[alpha], i[beta], u[alpha], and u[beta], and calculating an observed torque value Te; a PI speed regulator for calculating a given torque value (shown in the description) according to the rotational speed of the permanent magnet synchronous machine; a reference vector generation module for generating reference voltages usd and usq according to the difference between the observed torque value Te and the constant torque value (shown in the description) and a torque angle [delta]; an SVM control module for synthesizing reference voltages usd and usq into optimal voltage vectors Sa,Sb and Sc; and a three-phase inverter module for outputting a three-phase alternating current according to the input optimal voltage vectors Sa, Sb and Sc to realize the control over the rotational speed of the permanent magnet synchronous machine.

Description

technical field [0001] The invention relates to the field of torque control, in particular to a direct torque control system without a magnetic link. Background technique [0002] Permanent Magnet Synchronous Motor (PMSM, Permanent Magnet Synchronous Machine) direct torque control does not have the complex coordinate transformation of vector control, it can directly control the torque (DTC, Direct Torque Control), and has good dynamic performance, and more and more It is used in various occasions that require high motor performance. The traditional permanent magnet synchronous motor DTC is given the stator flux linkage with constant amplitude, the torque difference and the flux linkage difference are passed through the hysteresis comparator, and the output signal of the hysteresis comparator is obtained through the optimal switch vector table. Control the change of the motor torque angle to realize the effective control of the motor torque. [0003] The defects of the perm...

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Problems solved by technology

[0004] The traditional permanent magnet synchronous motor direct torque control control system needs to give the appropriate stator flux linkage to make the control system have good control performance. However, given different motors, the amplitude of the stator flux linkage needs to be given again, the control System implementation is cumbersome and complex

[0005] The traditional permanent magnet synchronous motor direct torque control system does not get rid of the limitation of the asynchronous motor direct torque control theory, and still uses the method of fixing the stator flux linkage. The permanent magnet synchronous motor direct torque theory does not have its own uniqueness

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