Permanent Magnet Synchronous Servo Drive System Of The Neutral Point Clamped Topology Based On The Holtz Structure

Three-phase permanent magnet synchronous motors have a very broad prospect to save energy. The other advantages are a simple structure, small size, high efficiency, maximum ratio of torque and current and easy to heat and maintain.With the emergence of new permanent magnetic materials, permanent magnet synchronous servo motor are liked by more people. And gradually replacing the induction motor and DC motor applications in many fields, It will become a development trend of the future.The control strategy is very important to permanent magnet synchronous applied to the servo field. Seen from the mathematical model of the synchronous motor, current of d-axis and q-axis can be obtained accurately by converting coordinate. Based on the conventional theory of rotor filed-oriented vector control for permanent magnet synchronous machines,the stator armature current is decomposed into the d-axis current and its vertical q-axis current. The current of d-axis which is in the same direction to the rotor magnetic field weaken the rotor magnetic potential, the current of q-axis magnetic potential generates electromagnetic torque. The magnetic field vector control of PMSM makes it have excellent speed performance like DC motors.This paper studies the control method of permanent magnet synchronous motor and also focuses on the three-level pulse width modulation strategy. The sector division of the reference vector,the order and time of switches action are also presented. By building a mathematical model of the inverter with Matlab\Simulink, it simulates the output waveform and harmonic content of the SVPWM modulation algorithm.Furthermore, the process and result of controller test for a PMSM of2KW are given. The control system uses Freescale’s MC56F8345chip that is specifically for motor control areas of application. The system of software is written by C, which accomplished in codewarrior. The result shows that the design of the system has good dynamic and static properties and meets the expected effect under the rated load.