Speed Servo System Of PMSM Based On Fuzzy-PI Controller With Voltage Booster

The permanent-magnet synchronous motor (PMSM) is a superiority-performance and widely-used motor. There are two main operations of PM motors over a wide speed range. These are performed by the flux-weakening operation in the high-speed region or a pulse width-modulation (PWM) inverter with a dc-link voltage control circuit. The PWM inverter with voltage booster consists of a voltage booster to control the dc-link voltage and a conventional PWM inverter, which drives the interior permanent-magnet synchronous motor (IPMSM) for a wide speed range. The former is a more conventional method. However, this operation needs additional current to reduce the magnet flux of the motor and the current increases copper loss. The latter is another solution. This drive system mainly has several advantages over drives with flux-weakening operation as follows. Firstly, this drive system does not need the current to reduce the magnet flux of the motor, so no additional copper loss by the current is generated. Secondly, PMSM has always been operating in the constant torque region, so the motor has more power. Thirdly, if the gating signal is suddenly removed from the inverter switches during high-speed operation, the amplitude of the line-to-line back eleoctromotive force (EMF) generated by the spinning PM rotor magnets is kept under the dc-link voltage. Therefore, this system has no probability of serious faults.The speed servo system of PMSM usually adopts the PI control method. The PI algorithm is comparatively easier and has some control accuracy. But the traditional PI controller is not adapted to the nonlinear and varied system. On the other hand, the fuzzy controller is not dependent on the system parameters and has good robustness. The structure and characteristics of the speed servo system are analyzed in the paper. And by integrating the advantages of PI and fuzzy controller, a fuzzy-PI hybrid control scheme is proposed to control the speed of IPMSM and the dc-link voltage. With the appearance of oscillation and overshoot, the fuzzy-PI hybrid control scheme can alternate between PI and fuzzy controller to keep the system working well with high dynamic and static performance.This paper introduces IPMSM and expatiates on the control strategy about speed servo system of IPMSM with voltage booster. Because of superiority performance and abundant external devices of the TMS320LF2407-A control chip, we use this kind of...