Flux Saturation Modeling Considering Cross-Saturation Phenomenon of Synchronous Machines and their Self-Commissioning Algorithms

Abstract

This thesis proposes an equation-based flux saturation model and parameter estimation method for synchronous motors, including SynRMs and IPMSMs, for the self-commissioning method at a standstill. The standstill self-commissioning method identifies the characteristics of the motor when the rotor cannot move before driving and is mainly used in systems using general-purpose inverters without FEA information about the motor. The hysteresis voltage injection method is used to obtain flux saturation data of the motor at a standstill. The hysteretic voltage injection method can collect magnetic flux data in hundreds of ms but cannot obtain magnetic flux data with respect to grid-shaped current. Therefore, equation-based modeling is more suitable than table-based modeling to perform flux saturation modeling using magnetic flux data obtained through this method. Existing equation-based flux saturation models had complicated equations or did not express the flux saturation phenomenon well. Additionally, parameter estimation methods for the model have not been studied. Because of these problems, it cannot be used in a self-commissioning method at a standstill. This thesis proposes a flux saturation model considering the flux saturation of SynRMs and ideal IPMSMs and a parameter estimation method using the linear least square method (LSM) that can be applied to embedded systems. The flux saturation modeling is completed during the hysteresis voltage injection process using the proposed flux saturation model and parameter estimation method. Additionally, the flux saturation model is proposed by considering the flux saturation phenomenon of actual IPMSMs. The parameters of this flux saturation model were estimated using the trust-region method, one of the nonlinear LSM. This thesis describes the flux saturation phenomenon of synchronous motors, including SynRMs and IPMSMs, the flux saturation model design method, and parameter estimation methods. The proposed flux saturation model and parameter estimation method were verified with 1.5 kW SynRM, 150 kW IPMSM, and 11 kW IPMSM.

Keywords: flux saturation model, self-saturation, cross-saturation, synchronous reluctance machine, permanent magnet synchronous machine