In this paper, the working principle of single-phase voltage-type PWM rectiifer is analyzed, and a mathematical model of the rectiifer is established. By using instantaneous direct current control strategy and policy, the parameters of PI controller which contains voltage loop and current loop are determined. The system is simulated and analyzed by using the Matlab/Simulink simulation platform. A 1 kW experimental prototype gave satisfactory charging curves and power factor correction results.

This paper proposes a harmonic current detection algorithm based on the sliding-window iteration discrete Fourier transform(SDFT) which has been improved by sliding-window iteration.The algorithm is applied in single-phase shunt active power filter(APF) to extract the harmonic current instruction.Simulation and experimental results show that as the loads are stable,it can accurately detect all kinds of the harmonic current.when the loads are changed,it can also get the harmonic current instruction with a cycle's delay.It's easy to be realized with digital processor.Single-phase shunt APF can effectively accomplish the detection and tracking of the harmonic current with the SDFT.

This paper firstly described the mathematical model of the doubly-fed machine in the dq coordi- nate system, and derived the mathematical model in MT coordinate system, with combinations of using, control strategies such as the stator flux oriented control, AC-DC converter in the rotor side, the hystere- sis control in Current loop and so on, and then drew the diagram of vector control of doubly-fed machine, and finally built a double-fed motor speed control system simulation model in the environment of MAT- LAB Simulink for simulation_

The battery is an important energy storage device in the EPS.The battery of EPS may produce excessive voltage when charging,and insufficient voltage when discharging.Long term excessive voltage or insufficient voltage will influence the normal operation of the EPS.The purpose of detecting the operational behavior of the battery in time is to maintain,overhaul or change the battery.Therefore, the design of EPS battery group detection module with MSP430F149 micro control unit as its core is worked out,which can examine the operation status ocular by making use of DSP as its master machine and LCD1602 as its display.

Montmorillonite was activated by acid and then polymerized with alkali to prepare poly- montmorillonite-based flocculant(PMT),and was used for removal of TOC and chroma in dyeing wastewater.The experimental results show that:Under the optimum conditions of PMT dosages 0.30 g/L for 2BLN,0.30 g/L for KNR and 0.25 g/L for X-3B,the TOC removal rates of the 3 kinds of simulated dyeing wastewater are 77.0%,89.2%,39.5%,the chroma removal rates are 41.2%, 43.1%,57.4%,respectively.The TOC removal rates of KNR and 2BLN actual wastewater by PMT are 91.6% and 88.4%,which are higher than those by PAC and PFS,whereas the TOC removal rate of X-3B actual wastewater and the chroma removal rates of the 3 kinds of actual dyeing wastewater by PMT are all lower than those by PAC and PFS.