The Study Of Permanent Magnet Synchronous Motors Control System That Checks Position Using High Frequency Voltage Signal Injection

Permanent magnet (PM) synchronous motors have been widely applied in AC timing drive over the last two decades due to their high efficiency, high power density and no exciting current. But their high performance control requires accurate rotor position and velocity signals to realize field orientation. In conventional motion control systems, photoelectric encoders or rotary transformers are used for this purpose. However, these mechanical sensors increase the costs of the system and decrease the reliability. With this background, the research of elimination these devices have been an attractive prospect. In last several years, there have been numerous publications on sensorless operation, but most of these techniques only rely on the fundamental machine equations, which limits the low speed and zero speed operation of the machine, and are sensitive to the machine parameters. Thus, the thesis focuses on the sensorless operation, its main content as follows:First, it introduces PWM technology of spatial voltage vector and imports methods that suited for DSP and calculated PWM width under the coordinate system of two stators.Next, it puts forward a new permanent magnetism synchronous machine rotor initial point estimate method — High frequency signals injection method. Based on the thought of salient pole tracking, the paper studied the application of this method in sensorless control of PMSM in detail. Introduced the principal of self detect rotor position for high frequency signals injection method and using these established the simulation model of PMSM sensorless vector control system, then simulate. The result indicated that, the salient pole tracking system that using high frequency voltage signals has more advantages, it has simple structure, good static and dynamic timing performance and easy realization. This method can effectively detect rotor's position and velocity in full speed scope .The sensorless vector control system has good static and dynamic performance, more ever, it is insensitivity to the change of motor parameters.Finally, the paper simulated to the rotor initial point estimate method using DSP related tool and confirmed the accuracy of high frequency voltage signal method.