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Firstly, it introduces the different operating modes and control mechanism of the high-voltage DC transmission (HVDC) system and analyzes the fuzzy control theory. On this basis, using MATLAB, a typical 12-pulse HVDC transmission system model of the bridge has been simulated under the control of traditional PI and fuzzy intelligent respectively. Compared with the traditional control methods, the real-time...
PWM rectifier technology is introduced to the main Power Circuit of the charger for aircraft battery to enhance the charging efficiency of aircraft battery and improve its long term reliability and save its life in this paper. A new strategy of DPC Based on the Space Vector Modulation (SVM) is used in PWM rectifier, Meanwhile, a fuzzy PI controller is designed in DC voltage control loop. The simulation...
The design of the voltage loop and current loop of three-phase high power factor PWM rectifier was introduced, the strategy of dual-mode control that combine fuzzy control to PI regulator is proposed, which use fuzzy controller to obtain quick dynamic response when deviation is in small range and adopt PI regulator to realize no static error when deviation is in long range, improving the control accuracy...
Stability issues are a major concern in railway grids. Although these problems are most experienced in 16.7-Hz applications, low-frequency oscillations also occur in 50-Hz railway grids. In this paper, an advanced multivariable control concept is presented. Beside achieving very good dynamic behavior, the approach improves the introduced stability problem. The proper operation of the control is verified...
Stability aspects are a major concern in railway-traction applications. It is well-known that low-frequency oscillations occur in 16.7-Hz railway-grids. They can be initiated either by impedance variation or by multiple traction vehicles active in one feeding section. This paper focuses on the emulation of many traction vehicles starting up in the same feeding section and hereby causing instability...
A tension adaptive variable-structure control system was designed for constant tension of electric cable plastic wrapping automatic production process. This system contains two inner loops for current and velocity control using PI regulators; its outer loop is for tension control using model reference adaptive controller. Simulation results indicate that the adaptive variable-structure controller...
Aiming at the problems that traditional PI control of DC capacitor voltage has Udc slow dynamic response, the period averaging dynamic model of APF including Vdc is established based on KVL. In order to have a good linearization control effect, the inverse control strategies is presented for three-phase four-leg Active Power Filter, and Aiming at the problem that the APF's dynamic model is a multi...
This paper presents and compares the performance of two controllers namely Fuzzy Logic and Proportional Integral applied to a voltage source inverter/converter operating as an active power filter. The active power filter is operated to compensate harmonics and reactive power generated by the non-linear load and power factor correction simultaneously. This work is performed in order to make an accurate...
This paper proposes a new speed sensorless direct torque and flux controlled interior permanent magnet synchronous motor (IPMSM) drive. Closed-loop control of both the torque and stator flux linkage are achieved by using two proportional-integral (PI) controllers. The reference voltage vectors are generated by a space vector modulation (SVM) unit. The drive uses an adaptive sliding mode observer for...
There are many consumers and equipments in distributed generation (DG) systems and distributed networks which have rapid changes in the reactive power consumption. These changes can result in large variations in the load-side voltage that may affect the operation of other power consumers which are fed from Point of Common Coupling (PCC). In this paper a current control strategy for inverters, based...
This paper deals with the design, analysis and simulation of an online voltage envelope estimator and an online feed-forward neural network (FFNN) controller based distributed static compensator (DSTATCOM) controller. Existing controllers such as PI controller and offline neural network controller are fixed structures and provide satisfactory control only for certain problems for which they are designed...
The control strategy for three-phase-high-power-factor PWM rectifier is studied, and the methodology of building the small signal model of the main power circuit is proposed in this paper. High frequency model for the rectifier mentioned and the input-to-output transfer function for the system are deduced with analysis. Design principle and method of the voltage regulator are given based on the model...
The current source back-to-back converters have been largely neglected because of the slow transient response and low power factor, which is mainly resulted from a fixed PWM pattern and a poor control method. However, current source converters have intrinsic advantages such as the high reliability and the inherent current limiting capability. Due to these advantages, more and more people have been...
This paper presents the analysis and operation of doubly fed induction generator (DFIG)-based wind power generation system under unbalanced network voltage conditions. The limited voltage and current ratings, the control capabilities of both the grid-side and the rotor-side converter (GSC & RSC) for unbalanced network voltage compensation are investigated in detail. A new current control scheme,...
Z-Source inverters have recently been proposed as new power conversion concept as they have both voltage buck and boost features. A unique impedance network between the power source and converter circuit provides both voltage buck and boost properties, which cannot be achieved with conventional voltage-source and current-source inverters. This paper presents a neural network control system that control...
Based on a three-phase PV grid-connected inverter with LCL filter, a two-current-loop control strategy which utilizes the grid-current as the outer-loop variable and filter-capacitor current as the inner-loop is adopted. Since the decoupling of the LCL filter is too complicate under dq coordinates, a PR controller is adopted in the outer loop under alphaszlig coordinates to avoid the complicated decoupling...
This paper proposes a four-multiple pulse width modulation (PWM) converter for grid interface, which is apply to the variable-speed constant-frequency direct-drive wind turbine systems. The paper introduces the principle of PWM converter, in order to improve DC voltage utilization, space vector pulse width modulation (SVPWM) technology is adopted. Then the advantages of the multiple based on carrier...
In this paper introduced a design of the active controllable energy feedback device (ACEFD) based on dsPIC30F DSP and d-q controller. Through establishing the synchronous rotating coordinate system (dq) model, we may achieve the decoupling feed-forward control method; the advantages are discussed in the following paragraphs. We also analysis the inner current control model and calculate accurately...
In synchronous rotating frame (SRF), the mathematical mode of a three-phase PWM VSI with LC filter is complex, and the dq components have cross coupling terms. In order to obtain good dynamic and static performance, the controller structure should be inherently based on the systempsilas mathematical model, which means that the decoupling control strategy with feed-forward should be adopted. But this...
This paper models the three-phase boost-type rectifier as switched linear systems (SLS) in the d-q reference frame which includes six available subsystems, so the problems of PFC and DC-bus voltage regulation are transformed to stabilizing the SLS. And then a novel control rule based on min-projection strategy is proposed, which controls the switching sequence around the six subsystems such that the...
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