Permanent magnet synchronous motor low speed section position sensorless control method without high frequency signal injection

Abstract

A permanent magnet synchronous motor low speed section position sensorless control method without high frequency signal injection is disclosed. An asymmetric space vector pulse width modulation methodis adopted, three effective voltage vectors with electrical angle difference of 120 degrees and one zero vector are used to synthesize a target vector, so that when the system is in the low modulation region or even the output target voltage vector is zero, the three effective vectors are not zero in the action time and large enough to ensure detection of the phase current change under the actionof the effective voltage vectors; based on the inductance convex polarity principle, the current variation of three effective voltage vectors and one zero vector are calculated, and a rotor positionis estimated from those current variations including position information. The invention can realize low speed segment position sensorless control without high frequency signal injection.

Description

technical field [0001] The invention belongs to the field of permanent magnet synchronous motor control, in particular to a low-speed position sensorless control method of a permanent magnet synchronous motor. Background technique [0002] Permanent Magnet Synchronous Machine (PMSM) is widely used in rail transit, robotics, household motors and other fields due to its advantages of high efficiency, high power density and wide speed range. PMSM position sensorless control has the advantages of low cost, small size and low failure rate because it eliminates the position or speed sensor, which has attracted extensive attention from experts, scholars and industries. [0003] The position sensorless control of conventional permanent magnet synchronous motors at low speed needs to inject high-frequency signals to excite the inductive saliency characteristics of the motor, and obtain rotor position information from high-frequency currents. However, the injected high-frequency sign...

AI Technical Summary

Problems solved by technology

[0004] In order to overcome the shortcomings of the high-frequency signal injection method itself and the poor control quality of the existing permanent magnet synchronous motor control method without a position sensor, the present invention provides a PMSM low-speed position sensorless control method without high-frequency signal injection, which improves the control quality of the PMSM. Quality of position sensor control

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