Predictive current control method based on pmsm model of npc type three-level inverter

Abstract

The invention discloses a current control method based on NPC three-level inverter PMSM three-vector model prediction, comprising: acquiring sampling information, including obtaining the rotor position θ of a permanent magnet synchronous motor through a photoelectric encoder; In the algorithm, the constraint conditions are used to reduce the number of candidate voltage vectors of the three-level inverter; the weight coefficient is added to the value function of the model predictive current control algorithm to control the midpoint voltage balance of the NPC three-level inverter; The sampling information calculates the action time value of each voltage vector, and based on the time value, the three-vector model predictive current control algorithm is used to determine the specific action of the three-vector control algorithm; the control signal obtained by the three-vector model predictive current control algorithm is transmitted to the NPC In the three-level inverter, the permanent magnet synchronous motor is controlled.

Description

technical field [0001] The invention relates to the field of motor control, in particular to a predictive current control method based on an NPC type three-level inverter PMSM three-vector model. 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, due to the fact that the permanent magnet synchronous motor has problems such as multi-variable coupling, nonlinearity and uncertainty under the 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 al...

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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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