Parameter identification for MTPA control based on a nonlinear d-q dynamic IPMSM model

Abstract

Purpose Small highly saturated interior permanent magnet- synchronous machines (IPMSMs) show a very nonlinear behaviour. Such machines are mostly controlled with a closed-loop cascade control, which is based on a d-q two-axis dynamic model with constant concentrated parameters to calculate the control parameters. This paper aims to present the identification of a complete current- and rotor position-dependent d-q dynamic model, which is derived by using a finite element method (FEM) simulation. The machine’s constant parameters are determined for an operation on the maximum torque per ampere (MTPA) curve. The obtained MTPA control performance was evaluated on the complete FEM-based nonlinear d-q model. Design/methodology/approach A FEM model was used to determine the nonlinear properties of the complete d-q dynamic model of the IPMSM. Furthermore, a fitting procedure based on the nonlinear MTPA curve is proposed to determine adequate constant parameters for MTPA operation of the IPMSM. Findings The current-dependent d-q dynamic model of the machine models the relevant dynamic behaviour of the complete current- and rotor position-dependent FEM-based d-q dynamic model. The most adequate control response was achieved while using the constant parameters fitted to the nonlinear MTPA curve by using the proposed method. Originality/value The effect on the motor’s steady-state and dynamic behaviour of differently complex d-q dynamic models was evaluated. A workflow to obtain constant set of parameters for the decoupled operation in the MTPA region was developed and their effect on the control response was analysed.

Optimization of an IPMSM for Constant-Angle Square-Wave Control of a BLDC Drive

“…The Simulink/Simscape environment was used to model the IPMSM, inverter, and control. First, a computationally efficient reduced order model (ROM) of the IPMSM was constructed by performing a series of FEM simulations of both analyzed IPMSM designs by varying the i d and i q input currents, as presented in [18,34,36]. An IPMSM model in the d-q reference frame was set up and connected to a voltage source inverter in the delta connection.…”

“…Many authors are researching this topic, the MTPA strategy for direct torque control for an IPMSM was deployed in [15], the signal injection to correct the MTPA angle in an IPMSM was deployed in [16], and the constraints for obtaining the MTPA line for PMSM control are presented in [17]. The best fit of the nonlinear MTPA line, which was then used in the control of the IPMSM, is presented in [18].…”

“…Third, the selected IPMSM design and the reference design were implemented in a system-level simulation, where the nonlinear IPMSM, inverter, and control were coupled, as shown in [18,34]. How to implement the abc reference frame IPMSM model in a simulation is presented in [35], whereas [36] shows how to reduce the computation time to obtain nonlinear machine models for system-level simulation.…”