Research On The Design And Control Of Phase-Decoupled Permanent Magnet Synchronous Motors

From the angle of integrity of motor and its control technique, a novel self-controlled permanent magnetic motor with the phase-decoupling (DPMSM) characteristic is put forward in the paper. The decoupling between the magnetic circuits of different motor phases is accomplished in the motor, thus lowering the strong decoupling characteristic and improving the control performance of PMSM. This paper focuses on the research of the design and control technique of DPMSM.From the angle of motor design, a special matching pattern of tooth and slot numbers and winding arrangement are employed to accomplish the decoupling between the magnetic circuits of motor phases. According to the demand of high-performance drive system in dynamic response, a novel magnetism-focusing rotor structure with auxiliary magnetic poles is put forward, in which the rotor magnetic flux leakage is effectively curbed and the magnetic flux density in the air-gap is remarkably strengthened leading to the improvement of dynamic response. An in-depth analysis about the influence on the curbing effect of magnetic flux leakage and improvement of air-gap magnetic flux density by using different types of magnetic materials are conducted in the paper. Aiming at the torque ripple caused by the departure of emf from idle waveform, an in-depth research on the optimizing design technique of emf from the aspects of winding design, eccentric air-gap design and rotor magnetic circuit structure design. In the end, the feasibility and correctness of the design principles are validated through the simulation and experiment results of the sample motor.DPMSM can not meet the presuppositions of the Park transformation due to the fact that the mutual inductance is far more less than the self inductance. The special working principal of DPMSM leads to the particularity in its control technique. According to the phase-decoupling characteristic of DPMSM, a novel control strategy of constant torque andconstant power operation based on the scalar conception is put forward. In constant torque region, the phase-independent direct torque control can be obtained by controlling the motor current of each phase without resort to vector transformation. In constant power region, a new conception of utilizing the voltage on the phase inductance to counter the emf by the technique of phase current pre-conduction against the phase emf is put forward. Thus, the invalidation of current control in the high-speed region can be avoided, leading to the expansion of speed range. Aiming at the low utilization of DC voltage in the current control, a pre-conduction of phase voltage against emf is also put forward, in which the maximum output voltage of inverter can be increased leading to a wider speed control range than the current pre-conduction control. During the operation, an initial pre-conduction angle is obtained according to the fundamental component analytical method. The online adjustment of the pre-conduction angle is employed to ensure that the input power is minimum.High performance sine-wave current tracing technique is the key to ensure the steady and dynamic control performance of DPMSM. A high performance current controller based on the fast switching MOSFET is designed and realized. The design approaches of the operation pattern and hardware system is also given. Based on the experiment results, the factors influencing the current control performance are analyzed. Aiming at the contradiction between high performance current control and low switching loss, a closed-loop control of sample frequency employing fuzzy decision is put forward. According to the different operation conditions of the driving system, the auto-adjustment of sample frequency can ensure that the driving system possess high efficiency and high current control performance during all the operation range.Aiming at the limitation of the sine-wave driving technique in low cost applications due to the reason of high cost rotor position sensor, a research on the continuous rotor estimation technique and related low cost sine-wave driving technique is conducted. The working principal of low cost...