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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...
The performance of HVDC system depends on the parameters of control system, and usually PI controllers have been used to adjust system to fulfill desired objectives. However, the optimization methods for PI controllers' parameters of HVDC system are very few up to now. And when the optimization task comes to RTDS, it becomes more complex. This paper introduces the Simplex Algorithm and its application...
This paper designed a double close loop control system based on current and voltage. As the system instable in some cases, the traditional PI regulator can not regulate the system more precisely. To make a more stable and better control effect, it should be improved by using Neural Network Control to get a feedback adaptive control system of PWM rectifier in order to achieve better results.
Voltage-source multilevel inverters have become very attractive for power industries in power electronics applications during last years. The main purposes that have led to the development of the studies about multilevel inverters are the generation of output voltage signals with low harmonic distortion; the reduction of switching frequency. A serious constraint in a multilevel inverter is the capacitor...
In order to eliminate the pulsating instantaneous power of twice of the output voltage frequency in case of single-phase load, a proportional-integral-resonant (PIR) based controller is proposed in this paper for the PWM rectifier in both the dc-link voltage control loop and the ac current control loop. The resonant regulator is very suitable for tracking the ac component, which provides the optimum...
The three-level PWM rectifier topology has been studied in this paper, and the decoupled state-space equations in synchronous rotating reference frame (d-q frame) were derived. The hierarchical controller structure is adopted, namely, the inner current-loop is responsible for reference current tracking and the outer voltage-loop is responsible for load regulation. The design methodologies for proportional-integral...
This paper presents a direct torque control (DTC) applied to a three-phase asynchronous motor supplied by three-phase rectifier with absorption of the sinusoidal current cascaded with a two levels inverter in order to improve certain electrical sizes as the source current, and other mechanical characteristics as the undulations of the torque and the flux's distortion. The speed control is realised...
Control of an advanced high-speed flywheel energy storage system (FESS) based on a high-speed surface mount permanent magnet synchronous machine (PMSM) is explored in this paper. A PWM inverter/rectifier controls the bi-directional flow of energy for charging and discharging the flywheel. During charging, an inner current loop controller and an outer speed loop controller regulate the system performance...
A voltage and current double closed-loop control method based on plural PI controller against two-stage matrix converter is developed. the compound vector models of the inverter side are established in d-q frame by introducing compound vector, a dual-loop control strategy which has the function of decoupling is presented accordingly by adopting the models, the plural PI controllers are designed to...
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...
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