PMSM three-vector model predictive current control method based on NPC type three-level inverter

Abstract

The invention discloses a PMSM three-vector model predictive current control method based on an NPC type three-level inverter. The methodcomprises the steps of obtaining the sampling information, and obtaining a rotor position theta of a permanent magnet synchronous motor (PMSM) through a photoelectric encoder; in a model prediction current control algorithm, reducing the number of alternative voltage vectors of the three-level inverter by using constraint conditions; adding a weight coefficient into a value function of the model prediction current control algorithm, and controlling the neutral-point voltage balance of the NPC type three-level inverter; calculating the action time value of each voltage vector according to the sampling information, and determining the specific action condition of the three-vector control algorithm by adopting a three-vector model predictive current control algorithm based on the time value; and transmitting a control signal obtained by the three-vector model predictive current control algorithm to the NPC type three-level inverter so as to control the permanent magnet synchronous motor.

Description

technical field [0001] The invention relates to the field of motor control, in particular to a PMSM three-vector model predictive current control method based on an NPC type three-level inverter. Background technique [0002] The AC permanent magnet synchronous motor is a high-performance motor with a position sensor. It has become the main executive motor of the AC servo control system due to its advantages of high efficiency and small torque ripple. Generally, traditional control algorithms such as PID controller or direct torque control are used to control permanent magnet synchronous motors. However, there are problems such as multivariable coupling, nonlinearity and uncertainty in permanent magnet synchronous motors under actual working conditions. Therefore, the effect obtained by using the traditional PID current controller or some traditional control algorithms is not ideal and has certain limitations. And because the model predictive control algorithm has the adva...

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Problems solved by technology

However, because the traditional two-level inverter is used, only seven basic voltage vectors can be used, and the non-zero vectors are all voltage vectors with the same amplitude. In many moments during the synthesis process, the three-level inverter control Compared with the distance from the target voltage vector, the difference is larger

Moreover, the three vectors used are based on the principle that two non-zero voltage vectors are continuous vectors and the zero voltage vector whose upper bridge arm is not turned on is the three vectors. In the end, only six vector combinations are selected, which is very limited and the synthetic voltage Vector coverage is small

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