PWM rectifier

About: PWM rectifier is a research topic. Over the lifetime, 2254 publications have been published within this topic receiving 25614 citations.

A Virtual Admittance Control Strategy of Three-Phase Voltage Source PWM Rectifier Under Unbalanced Input Voltage Conditions

Abstract: A virtual admittance control strategy is proposed for three-phase voltage source PWM rectifier by analysis on the time-domain relationship between three-phase AC current and three-phase AC voltage under unbalanced input voltage conditions. The strategy does not only simplify the control algorithm, but also realize wanted power factor by the Coordinate Transformation. With reduced computation and improved speediness, generalized integrator is also introduced to realize static error free tracking control of positive and negative sequence current on two-phase static frame. Extensive simulation and experimental results verify the correctness of the proposed control strategy.

Direct Power Control Strategy of PWM Rectifier Based on Improved Virtual Flux-Linkage Observer

Abstract: In order to achieve the low cost and high performance control of three-phase PWM rectifier, a direct power control (DPC) strategy based on a new-style virtual flux-linkage observer is proposed. The model of three-phase PWM rectifier and the principle of virtual flux-linkage vector control are introduced firstly. Then, in order to avoid the effect of integral initial value and cumulative deviation, three first-order low-pass filters are cascaded to replace the pure integral link; an improved virtual flux-linkage observer of three-phase power grid is presented. From the observed virtual flux-linkage, the voltage and instantaneous power of three-phase power grid are online estimated. On this basis, the power grid voltage sensorless direct power control system of three-phase PWM rectifier is designed. Simulation results have shown that, both in the rectifying state and in the inverting state, the power grid side current and the DC side voltage of three-phase PWM rectifier all can be effectively controlled; the high power factor operation of three-phase PWM rectifier is realized.

Hybrid cascade multilevel electronic power transformer

Abstract: The invention discloses a hybrid cascade multilevel electronic power transformer. The hybrid cascade multilevel electronic power transformer comprises A, B and C-phase electric energy transformation units with the same structure, wherein each phase electric energy transformation unit is formed by concatenation of M sub-units of the electronic power transformer, and M is not less than 2; each sub-unit of the electronic power transformer comprises a three-stage structure formed by series connection of a high-voltage stage, an isolation stage and a low-voltage stage; each high-voltage stage comprises a PWM (pulse width modulation) rectifier, each PWM rectifier is in concatenation with the PWM rectifiers of other sub-units in the same phase, each isolation stage comprises an isolation type DC-DC (direct current-direct current) converter, each low-voltage stage is of a voltage source inverter, and each voltage source inverter is in concatenation with the voltage source inverters of other sub-units in the same phase; and the alternating current input ends of the PWM rectifiers and the direct current output ends of the voltage source inverters are respectively connected with reactors in series. The hybrid cascade multilevel electronic power transformer disclosed by the invention can be used for improving the quality of electric energy by expanding the level number of output voltage; and furthermore, a used switching device does not need to be limited by the same frequency, thereby reducing the loss of a switch and a filter.

Single-phase PWM rectifier dynamic performance optimization control method based on active disturbance rejection control

Abstract: The invention discloses a single-phase PWM rectifier dynamic performance optimization control method based on active disturbance rejection control. The method adopts double closed-loop control of a voltage outer loop and a current inner loop, the current inner loop adopts single-phase DQ current decoupling control and the voltage outer loop adopts active disturbance rejection control. In particular, according to the principle of power conservation, a mathematical model for active DC components isd of single-phase PWM rectifier output DC voltage udc and grid-side AC voltage is deduced; and according to the mathematical model, a voltage outer loop active disturbance rejection controller is designed. In comparison with the traditional single-phase DQ current decoupling control voltage outer loop adopting PI control, the voltage outer loop in the invention adopts active disturbance rejection control, and while grid-side unit power factor operation and DC-side voltage stable control are realized, the dynamic response speed of the system is better and the anti-interference ability is stronger.

The Simulation of Three-Phase Voltage Source PWM Rectifier

Abstract: Three-phase PWM voltage rectifier (VSR) applies Pulse Width Modulation (PWM) technology, it can overcomes the drawbacks of the conventional rectifiers, and has higher power factor, lower harmonic current and rapid dynamic respond, so VSR used widespread. In this paper a dual-channel closed-loop control strategy with current-inner-loop and voltage-outer-loop is adopted for VSR, which makes the DC-side voltage remain steady and the system will run in unit factor. A simulation model of VSR is established, proper parameters are selected, and the control result is fine.