Research On High-power Flux-weakening Control And Parameter Identification Of IPMSM

Permanent magnet synchronous motor(PMSM)is widely used in servo drive,hybrid vehicle,aerospace and military industry due to its advantages of high power density,high torque density and high efficiency.Compared with the surface-mounted permanent magnet synchronous motor(SPMSM),the interior permanent magnet synchronous motor(IPMSM)becomes a research hotspot due to its unique weak magnetic expansion ability.In order to meet the requirements of the IPMSM to adapt to various actual operating conditions,the current scholars focus on the study of high-efficiency current optimization control strategy,motor parameter identification technology,high-power flux-weakening control technology and other aspects.This paper studies these problems on the basis of the IPMSM.The speed range and stability of IPMSM drive system is the research direction of IPMSM high-power flux-weakening control.On the basis of the vector control and the theory of voltage limit ellipse and current limit circle,this paper studies and analyzes IPMSM current optimization control technology in different velocity domains.Then,the effect of voltage coupling on the performance of high-power flux-weakening control system is discussed and analyzed,and the current feedback decoupling-control strategy is studied.Based on the analysis of the effect of digital control delay on system voltage output at low carrier ratio,the corresponding compensation method is given.In this paper,the protection of uncontrolled at high speed and braking technology are studied,and the corresponding control strategy is proposed.Then,the performances of several commonly used flux-weakening control strategies are compared and analyzed.The flux-weakening control method of single current regulator based on voltage vector angle is studied.The stability of the system is improved by improving the voltage feedback flux-weakening control strategy.Finally,the simulation and experimental platform of IPMSM highpower flux-weakening control is built,and the correctness and feasibility of the theory are verified by the waveforms of running speed of the motor and the dynamic and steadystate of the current.Because IPMSM is a time-varying object,which multi-variable,strongly coupled and nonlinear.Parameter identification technology is very necessary for the design of high precision and high-efficiency of IPMSM drive system controller.For parameter identification technology,this paper first discusses and analyzes the effect of the factors such as temperature,magnetic saturation,skin effect and the influence of parameter error on the control system.Then studies the problems existing in the common motor parameter identification technology,this paper analyzes the nonlinear impact on output voltage inverter and compensation scheme is given.For IPMSM parameter identification technology,the off-line parameter identification process of four main motor parameters of IPMSM is studied respectively,the off-line identification method is simple in principle and easy in implementation.In view of the owe-rank problem of the multi-parameter online identification technology,this paper proposes a multiple parameters identification algorithm,which based on least squares and mutual update online.The algorithm solve the problem that the four main electrical parameters of IPMSM can't be identified at the same time by recognizing step by step,and then update to identify each other.In the end,through the simulation and experiment verified the correctness and feasibility of the scheme.