A Novel Discrete Control Technique of Matrix Converter for the Vector Control of Permanent Magnet Synchronous Motor

Aiming at unity power factor at source side and motor currents following the reference values accurately at load side, this paper introduces the weight function of optimization control for the PWM modulation of matrix converter (MC) and the flux-oriented control of permanent magnet synchronous motors (PMSM). For the MC-PMSM system, the circuit differential equations both at source side and at load side are presented at first. Then, based on the difference principle, the corresponding time-discrete equations are derived. Combining these equations with the relationships between the inputs and the outputs of MC, this paper figures out the discrete expressions that represent the MC-PMSM system and transfers them to the forms in d-q coordinate system. With the help of these expressions, the switching states of MC are determined by real-time calculation and optimization of the weight function to complete the following control of the motor currents and to approach the unity input power factor. Theoretical analysis and simulation are presented here. Finally, the measurements are taken on a prototype with a 3 kW PMSM. The experiment results are coincided with the simulation ones and the theoretical analysis results. The feasibility and the correctness of the time-discrete control technique of MC for PMSM vector control are verified