Research Of Ventilator Drive System Based On Freescale MC56F84789

Permanent magnet synchronous motors(PMSM) have been widely used in industry field due to simple structure, reliable operation, high power density, simpler control system, etc. However, in some harsh environments, the sensor may be influenced, which may affect the reliability of the control system. Besides, installation and maintenance of the sensor will increase the cost. Thus reducing system cost and improve system reliability has become a research emphasis for PMSM control system. The main task of this research is to build a drive system of 500 W SPMSM ventilator based on Freescale MC56F84789, sensorless vector control technology and phase current reconstruction technology are adopted, which provides the foundation for the following research of our lab. The main researches of this paper are as follows:In order to solve the problem of the position identification in low speed range, the I/F self-starting strategy is researched. The principle of torque versus power self-stabilization is analyzed. A transition strategy is introduced to achieve a smooth transition from speed-open-loop current-closed-loop state to sensorless vector control. At last the sensorless vector control algorithm is simulated to test and verify the amplitude in medium and high speed range.A phase current reconstruction strategy using a si ngle shunt current sensor is introduced. In some unmeasurable areas, the current reconstruction suffered from the low amplitude. In order to solve this problem, a PWM signals modification methods are used. The simulation model of the algorithm is built in MATLAB based on S function to verify the correctness of the algorithm. At last, the PWM signals modification methods are also simulated to test the impact to the sensorless vector control.The hardware design of the 500 W SPMSM drive system based on Freescale MC56F84789 is completed. The APFC convention circuit is also designed on the basis of one-cycle control IC IR1150 S. The circuit is simulated to verify the performance. The power switch circuit is also designed base on the IC LNK306. The main loop circuit, current and voltage detection circuit and drive circ uit is also designed. It provides the foundation for the following experiment.At last, the I/F self-starting strategy and the position sensorless vector control were validated using the Freesclae tower system platform.