Direct torque control device and method for permanent magnet synchronous motor

Abstract

The invention discloses a direct torque control device and a direct torque control method for a permanent magnet synchronous motor. The DC bus voltage of an inverter and a current signal of the permanent magnet synchronous motor are output to a signal detection circuit; the signal detection circuit outputs the DC bus voltage and the current signal to a processor; meanwhile, a rotating speed pulsesignal of the permanent magnet synchronous motor is output to the processor and is processed by the processor to form a proper switch signal which is then output to the inverter so as to control the motor. A proper voltage vector is selected from twelve synthesized voltage vectors according to a flux linkage error and a torque error and the position of the flux linkage in twelve sectors, and the duty ratio of the selected voltage vector is determined in real time according to the torque error so as to generate a proper inverter switch signal for controlling the permanent magnet synchronous motor. The number of the selectable voltage vectors in the traditional direct torque control is increased, the duty ratio of an acting vector is adjusted in real time according to the torque error, and the torque pulsation in the traditional direct torque control can be effectively reduced.

Description

technical field [0001] The invention belongs to the technical field of AC motor drive, in particular to a direct torque control device of a permanent magnet synchronous motor, and also relates to a control method using the device. Background technique [0002] Direct Torque Control (DTC) is a high-performance AC motor speed control strategy that has been widely used in asynchronous motors. The direct torque control method is to use the stator flux linkage and electromagnetic torque of the motor as the controlled variables, and directly select the voltage vector according to the given torque, the error between the given flux linkage and its calculated value, and the position of the stator flux linkage. Compared with vector control, direct torque control has the advantages of simple control method, quick torque response, and easy realization of full digitalization. At present, the application of this control method has also been extended to the permanent magnet synchronous mo...

AI Technical Summary

Problems solved by technology

[0004] The purpose of the present invention is to provide a direct torque control device for permanent magnet synchronous motors, which solves the problems of complex control in existing torque control methods and the need for a large number of calculations to realize space vector pulse width modulation

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