Standstill Inverter Nonlinearity Estimation at Arbitrary Rotor Position for Permanent-Magnet Synchronous Motor Drives

초록

This paper proposes an algorithm that extracts output resistance?which is sum of stator resistance and onresistance of power semiconductors?and inverter nonlinearity of permanent-magnet synchronous motor drive systems. The proposed method is not necessary to adjust rotor position and can be applied even when the motor is in a free-run state. Throughout the execution of the entire algorithm, the motor remains at standstill. The sum of the stator resistance and the inverter nonlinearity is modeled using nonlinear functions. The measured data are fitted to proposed model using a least square method to estimate both the stator resistance and the inverter nonlinearity. The proposed method can be implemented in the microprocessor and does not require any complex computation with the offline high-performance computer. To validate the effectiveness of the proposed approach, the algorithm was implemented on a 3.9 kW servo motor drive system. Experimental results confirm that the proposed method accurately estimates the voltage distortion due to the inverter nonlinearity without any rotor movement.