Coordinated Control of Sliding Mode and Hamiltonian for PWM Rectifier

Aiming at the PWM rectifier control strategy of sliding mode control, steady state performance weak Hamiltonian control dynamic tracking performance is poor, the coordinated compound control is proposed, the feedback linearization controller and sliding mode controller Hamiltonian system is obtained, and the design of a coordinated control strategy. In order to verify the accuracy of this method, MATLAB/Simulink is used for simulation analysis. The simulation results show that the composite control can achieve the coordinated dynamic rapid tracking and constant DC output and unit power factor operation, and satisfy the control requirements of the rectifier, effectively reducing the disturbance effect on the system. Compared with Hamiltonian control, the proposed method combines the advantages of the two methods, which have the fast tracking performance and excellent steady-state characteristics, and the research prospect is broad.

Research on Fault-tolerant Operation Strategy of Rectifier of Square Wave Motor in Wind Power System

In wind power system,the randomness of wind energy increases the probability of components fault.once the switch fault of the PWM rectifier is detected,it will lead to the distortion of the motor voltage and current waveform,the increase of torque ripple,the fluctuation of filter capacitor voltage,and the increase of harmonic content,which will affect the control performance and operation safety of the system.A common fault in a three-phase PWM rectifier is the open-circuit fault of the switch.This paper analyzes the current waveform distortion of the square wave motor when the rectifier switch fault,and proposes different fault-tolerant control strategies for different situations of switch fault,include single,double and triple switches fault.This method is based on several special driving modes under power generation situation of square wave motor.The strategy is easy to implement and does not need to change the circuit topology.It can realize fault-tolerant control of switch faults in the same side half bridge or the same bridge arm of the three-phase PWM rectifier.The effectiveness of the proposed fault-tolerant strategy is verified by simulation and experiment at the end of the article.

Research on power supply of booster based on PWM rectifier

Purpose The magnet power supply system of HEPS mainly includes the linear magnet power supply,the booster power supply,the transportation line magnet power supply and the storage ring magnet power supply.According to the physical design requirements,the output current of the booster magnet power supply is a current with a DC bias period of 1 Hz,and the waveform can be a sine wave or a trapezoidal wave(Jiang et al.Sci Sin Phys Mech Astron 44(10):1075-1094,2014).The dipole magnet of the booster should be powered in series,the inductance value is relatively large(about 160 mH),and the power of the power supply reaches several hundred kilowatts.Methods The three-phase PWM rectifier controls the orderly turn-on of power electronic devices and takes the input voltage phase of the power grid as the command current phase to make the input current waveform follow the power grid voltage,so as to achieve the purpose of improving the power factor.In this paper,the PWM rectifier is modeled and simulated,and based on the simulation,an experimental prototype is built.Results The experimental results of the power supply prototype of the PWM rectifier show that the PWM rectifier can achieve high power factor operation on the grid side(Akagi and Sato,in:Control and performance of a flywheel energy storage system based on a doubly-fed induction generator-motor for power conditioning,1999).Conclusions The PWM rectifier can be used in the power supply of the booster and has a very good application prospect.

Wide Speed Range Permanent Magnet Synchronous Generator Design for a DC Power System

A wide speed range permanent magnet synchronous generator(PMSG)system is studied in this paper,including the PMSG design and comparative study on control strategies with a pulse width modulation(PWM)rectifier,the purpose of which is to regulate the DC-link voltage.It is of great importance to study the foregoing DC power system based on the PMSG and PWM rectifier,where vector control(VC)can be implemented and the corresponding field-weakening strategy can be realized by injecting a field-weakening current component without any auxiliary devices.Large machine inductance is desired in order to limit the short-circuit current and the loaded voltage drop.Different control strategies including VC,direct torque control(DTC)and direct voltage control(DVC)are studied and compared with both simulations and experiments.