Electromagnetic torque ripple control of induction motor fed by dual frequency inverter

Direct torque control(DTC)of space vector modulation fed by dual frequency inverter is studied in order to solve the problems of large torque,big flux ripples and inconstant switching frequency of conventional DTC in large power occasions. On the basis of conventional DTC,factors affecting flux and torque ripples are analyzed and the space voltage vector mathematical model of induction motor is deduced,which is implemented by S-function. Based on dual frequency theory,the system is supplied by cascaded inverters to decrease losses. The high frequency unit is in charge of improving the dynamic performance of the system,whose switching current is relatively low;while the low frequency unit is in charge of energy delivery,whose switching frequency is far lower than that of the high frequency unit. The simulation results illustrate that by using this program,the system has a better performance in both dynamic and static performance,and the electromagnetic torque ripple,flux ripple and switching losses are significantly reduced. Thus the system efficiency is improved and suitable for medium and large power occasions.     

The design of torque dynamic sliding mode controller in permanent magnet synchronous generator for wind turbine

Permanent magnet synchronous generator for wind turbine is a multivariable nonlinear system with strong coupling. Considering the influence of the volatile parameters of the generator on the performance of vector control, the torque dynamic sliding-mode control strategy is further studied. The proposed first order dynamic sliding-mode control strategy reduces the chattering by using a new switch function constituted with derivative element. With the dynamic sliding-mode controller in the power outer loop, the PMSG vector control system shows excellent robustness and insensitivity to the parameters and disturbance, which is confirmed by simulation.     

Vector control of permanent magnet synchronous motor with variable DC-link voltage

As for the drive of control system in electric vehicles, if the inverter power is supplied by a constant DC-link voltage, there are some disadvantages in the system, such as small utilization of the voltage, big current harmonic distortion of the motor windings. A new strategy for vector control of permanent magnet synchronous motor (PMSM) with variable DC-link voltage is proposed, which is suitable for electric vehicles. According to the reference voltage amplitude of the inverter, the new system uses bidirectional DC/DC converter to adjust the DC-link voltage to improve the performance of the vector control system. At last, the whole system is simulated with MATLAB software. The simulation results show that the new strategy for vector control can increase voltage utilization, decrease torque ripple, improve current waveform effectively and decrease the total harmonic distortion of motor current. The results also verify the effectiveness and feasibility of the new strategy.     

Three level direct torque predictive controlbased on fast virtual vector modulation

A novel scheme based on voltage prediction and fast virtual vector modulation algorithm for direct torque control of a permanent magnet synchronous motor fed by diode clamped multi level inverter is proposed.The system is based on diode clamped three level inverter,which is widely applied to middle high voltage speed regulation.Combined with space vector modulation,the reference voltage vector for direct torque control is obtained by voltage predictive control algorithm,then zero vector and two adjacent virtual vectors are used to synthesize reference voltage vector based on non orthogonal 60° coordinate.The neutral point potential is controlled by using the neutral point current characteristics of small vectors,the desired basic voltages and their dwelling time can be easily obtained and fast space vector modulation is achieved.Simulation results verify the feasibility of the proposed control scheme,that dv/dt of output voltage and neutral point potential of three level inverter are restrained effectively,and high dynamic and steady performances are obtained.     

Modeling and simulation of the conducted electromagnetic interference for permanent magnet direct current motors

A simulation model for evaluation of conducted electromagnetic interference(EMI) is developed based on analysis of the mechanism giving rise to conducted EMI. The simulation model includes high frequency effects associated with stray distributed parameter     

Power model and tarepower characteristic of CNC machine tool feed system

A power model of a CNC machine tool feed system is proposed based on analyzing the power characteristic of each component in the CNC machine tool feed system. And the tarepower characteristic and its dominant affecting factors are analyzed by using the power model. The analysis results show that the tarepower of feed system is a monotone increasing quadratic function in term of the feed speed. Meanwhile, the feed speed and load mass both affect tarepower, but the influence of load mass is minuteness. Some experiments are conducted on a 3-axis CNC milling and the experimental results justify the theoretical analysis.     

simulation of a brushless direct current motor based on finite state machine theory

A novel method simulating a brushless direct current(DC) motor was presented, based on principles of hybrid system modeling and finite state machine theory. Brushless DC motor control mainly focuses on controlling the on/off condition and power switch duration. Modes of control therefore can be defined by corresponding states, and the states can be combined as a finite state machine. This approach uses the popular Simulink/Stateflow simulation method to control brushless DC motor loops. A three phase brushless DC motor was analyzed to illustrate the process of model building with Simulink/Stateflow. The analysis demonstrates the feasibility and validity of the proposed method.     

Modeling and control system simulation of automobile DCT

In order to reduce development time and cost of dual clutch automated mechanical transmission(DCT) control system,the dynamic model of automobile DCT control system is established by Matlab/SimDriveLine and the engine model is improved by neural network.Based on Matlab/Simulink,the simulation models of DCT control during starting phase,shift phase and shift rule are set up,and then the whole system of DCT is simulated.The simulation result indicates that the DCT system dynamic model and the designed controller are reasonable and feasible,and proofs that the model is suitable for developing DCT control system and improves the design efficiency of DCT system.     

Coordinated pressure control of a regenerative braking system based on a hybrid electric vehicle with an integrated startor and generator

With a focus on a Changan hybrid electric vehicle (HEV) with an integrated startor and generator (ISG), strategies for braking force distribution and coordinated pressure control are put forward, and a dynamic braking control model is constructed for off