| ABSTRACT:As a further deterioration of growing global energy crisis and environmental problems, new energy automobile as an efficient use of the limited resources of energy and environmentally friendly means of transport is concerned, it has also promoted the development of new energy vehicles. Research of electric vehicle also comply with this trend, the permanent magnet synchronous motor(PMSM) because of its relative to higher power density compared with DC motor and asynchronous motor control more excellent performance, has become an important object in the study of electric vehicle. Based on the mathematical model of PMSM, vector control method of the rotor flux orientation and further flux-weakening control of the PMSM were studied, using different flux-weakening control methods for motor to carry out simulation study and result analysis.The rotor structure of several kinds of PMSM are introduced, according to the non-salient pole and salient pole PMSM d-axis and q-axis inductance value, the mathematical model of each are established. The control technology of PMSM based on the mathematical model are introduced, they are field oriented control and direct torque control technology, id=0control and MTPA control are also analyzed.Flux-weakening control based on traditional double current regulator (DCR) for PMSM was studied, the introduction of concept of the voltage limited ellipse and current limited circle to better analysis flux-weakening. The motor is known to reach a maximum value at the output voltage of inverter before entering to the flux-weakening control mode, the traditional DCR flux-weakening control of common constant torque flux-weakening and leading angle methods are studied, the former is realized by tracking the intersection of voltage limit ellipse and constant torque curve, while the latter is through compensating current vector angle, the MTPV control is also introduced.Flux-weakening control based on single current regulator (SCR) was studied. In the traditional DCR flux-weakening control process, in the condition of deep flux-weakening the coupling degree between current regulators will aggravate, it may easy to make the control system out of control, in order to solve this problem, try to use SCR flux-weakening control, two kinds of flux-weakening control based on SCR were introduced respectively, they are voltage angle control (VAC) and variable q-axis voltage control (VQVC), their control principle were also analyzed.This paper finally established the model of vector control for PMSM to carry out the most basic id=0and MTPA simulation, and compare performance differences between these two control methods. It then studied several flux-weakening control methods of the traditional DCR in simulation, and analyzed their simulation results. Two methods of flux-weakening control based on SCR are studied, some waveforms of two kinds of control methods were compared. |
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