Study On Deadbeat Predictive Current Control Strategy Of Surface-Mounted Permanent Magnet Synchronous Motor

The surface-mounted permanent magnet synchronous motor(SPMSM)has been widely used in the industrial field due to its characteristics such as magnetic circuit symmetry and simple structure.Deadbeat predictive current control(DPCC),as one of the current prediction control algorithms,has become a research hotspot in recent years due to its simple programming,low current harmonic content,and fast dynamic response.However,the DPCC strategy based on the mathematical model of the motor may experience poor current tracking performance and even difficulty in ensuring stability under the influence of multiple disturbance factors such as control system delay,inverter nonlinearity,motor parameter mismatch,etc.To solve these problems,this thesis takes SPMSM as the research object and investigates two deadbeat predictive current control strategies based on different discretization motor models.It analyzes the impact of different disturbance factors on these two strategies in detail and proposes an improved disturbance compensation scheme with the goal of improving the steady-state performance of the current loop.On the one hand,for the DPCC strategy based on the traditional discretization motor model,this thesis first analyzes the influence of inverter nonlinearity and motor parameter mismatch on the steady-state performance of DPCC after considering control system delay compensation.For the inverter nonlinearity disturbance factor,based on considering error factors such as dead time,IGBT conduction voltage drop,turn-on and turn-off time,and freewheeling diode voltage drop,this thesis derives the error voltage formula of the inverter dq axis,quantitatively analyzes its influence on the steady-state error of DPCC,and constructs the dq axis voltage disturbance compensation equation.For the motor parameter mismatch disturbance,this thesis analyzes in detail the influence of parameter mismatch disturbance on DPCC steady-state error and current loop stability,and points out that the main parameters affecting DPCC steady-state error are inductance and magnetic flux linkage.This thesis derives the nominal inductance value range to maintain DPCC current loop stability.Secondly,a decoupling method for inductance and magnetic flux linkage parameters is adopted,which can make the identification of inductance parameters completely independent of other motor parameters.Combined with Kalman filtering algorithm,real-time estimation of two important parameters of inductance and magnetic flux linkage is realized,which effectively compensates for the steady-state error caused by parameter mismatch disturbance,improves the steady-state performance of DPCC well,and greatly reduces the complexity of calculation.On the other hand,for the incremental model based deadbeat predictive current control(IDPCC)strategy,this thesis also focuses on analyzing the influence of inverter nonlinearity and motor parameter mismatch disturbance on its steady-state performance.The analysis results show that IDPCC has little influence on steady-state error under the above two disturbance factors,especially for motor parameter disturbance within a certain range.However,the current loop stability of IDPCC is easily affected by inductance parameter mismatch.The theoretical derivation shows that the nominal inductance value range to maintain current loop stability is 0.8 to 1.25 times the actual inductance.To solve this problem,this thesis applies the decoupling inductance identification algorithm based on Kalman filtering adopted in the previous section to the IDPCC strategy to compensate for the adverse effects of inductance parameter mismatch on IDPCC current loop stability and improve the robustness of the control algorithm.To verify the effectiveness of the above two current deadbeat control strategies and disturbance compensation methods,this thesis constructed a Simulink simulation and SPMSM experimental platform.The experimental results show the correctness of the theoretical analysis.DPCC and IDPCC with disturbance compensation have good steady-state tracking performance and strong parameter robustness.Finally,according to the experimental results,this thesis summarizes and compares the two deadbeat control strategies from three aspects.This thesis has 86 figures,8 tables,and 64 references.