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In order to quicken the dynamic response and strengthen the ability against the disturbance of nonlinear load, three-phase voltage source PWM rectifier widely employs dual loop PI control scheme which consists of inner current controller and external voltage controller. The parameters of dual loop PI regulators have significant influence on the dc-link voltage, AC harmonic components and power factor...
This paper presents a performance comparison of PI and Linear Quadratic Regulator (LQR) controllers for regulating the output voltage of a boost DC-DC converter. Performance of these controllers has been tested under different disturbances in output voltage, input voltage, and load current using MATLAB/Simulink simulation package. The comparison indicates that LQR controller performance is better...
Hybrid modeling method provides a natural way to model the power converter, it describes the behavior of the converter more accurately in sense of no approximation. The switching control method based on the hybrid model can realize the stable regulation of the output voltage. However, the switching controller designed based on the common Lyapunov function (CLF) would lead to steady state error, when...
This paper deals with design of a synchronous frame control strategy for single-phase inverter-based islanded distributed generation (DG) systems. Although, implementation of these regulators requires a minimum of two independent phases in the system, the required orthogonal phase is generated through the use of a first order all pass filter (APF). The essence of the proposed control strategy is to...
New regulatory requirements outlined in the European Grid Code dictate fault ride-through and reactive power support requirements for wind energy conversion systems. This paper introduces a simple emergency control scheme for DFIG-based wind turbines to comply with the grid code requirements. The proposed control design uses an enhanced phase locked loop (PLL) system to extract the synchronization...
This paper presents a direct torque control method for doubly-fed induction generator (DFIG) based wind power generation systems. The angle and magnitude of rotor voltage are controlled to achieve independent control of electromagnetic torque and reactive power respectively. Space vector modulation is used to address the limitations like, variable switching frequency and torque ripple, of hysteresis...
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...
This paper deals with the fuzzy logic based proportional-integral (FPI) regulators for voltage and frequency control (VFC) of an isolated asynchronous generator (IAG) in a wind energy conversion system (WECS). A three-leg voltage source converter (VSC) with battery supported energy storage (BSES) is used as a VFC. The VFC algorithm uses two fuzzy PI regulators, to improve the dynamic performance of...
This paper describes conventional and advanced methods for the control of D-STATCOM. The mathematical model of conventional double loop control, Direct-Output-Voltage (DOV) control, Decoupled DOV, Fuzzy-PI and Decoupled Fuzzy-PI based control is studied. The control scheme for the above approaches is implemented using Matlab Simulink platform. The dynamic response of the models are presented and compared.
This paper presents a new method to improve the DC voltage response on the load change of a three-phase power converter space vector PWM with current regulator. The line current reference is generated from the load current referred to as control-side and the output of PI controller driven by DC voltage error. The load current estimation can be obtained by using the Luenberger observer. A simplified...
At present, vector control (VC) has been widely used in the interior permanent magnet synchronous motor (IPMSM). However, for the difference between direct and quadrature inductances and the difference of control characteristics between d-q axes current loop PI regulators, the dynamic decoupling can not be achieved, which affects the torque dynamic response and the quick startup of motor. For this...
It is difficult to obtain a more precise mathematical model of parallel-inverter system with a nonlinear load. Nonlinear load is the general factor which affects output voltage total harmonic distortion (THD) and current sharing. But fuzzy controller can control well without a precise mathematical model. Master-slave control is used to control the parallel-inverter system in this paper. The voltage...
This paper analyzes the effects of the decoupling of the cross-coupling terms when PI synchronous regulators are used in droop characteristic converter. The PI synchronous regulators are implemented for both voltage and current control. An analysis of the different working modes of the converter are presented. Three sub-modes for the island model, Conventional droop mode, power quality mode and Sync...
In this paper, a double-edge modulation based one-cycle-control (OCC) scheme is presented for regulation of active rectifier. With minor modifications made in OCC core, the nonlinear carrier formed by integration and reset of dc-link voltage error turns out to be a symmetrical triangle waveform in steady-state, which can effectively eliminate the even order harmonics generated by the conventional...
This paper introduces an effort to overcome the zero steady-state errors resulting from the direct use of the conventional PI regulators to AC signal. A novel type AC PI (P+Resonant) regulator based on the theory of carrier-servo control systems that DC regulators are converted into AC regulators is applied to the inverter. Theory analyses and simulations verified the validity of the new regulator...
Matrix converter (MC) is superior to drive induction motor since it has more attractive advantages than conventional pulse width modulation (PWM) inverter like the absence of large dc-link capacitor, unity input power factor and bi-directional power flow. However, due to the direct conversion characteristic of MC, the drive performance of induction motor is easy to be influenced by input voltage disturbances...
Traditional AC voltage regulator used servo-motor position regulation or thyristor phased controlled method which had low dynamic response speed or large amount of harmonic components. However, these drawbacks can be overcome by using Pusle Width Modulation chopper techniques in AC voltage regulation. Buck-Boost Chopper type AC voltage regulator, derived from the DC chopper modulated method, is a...
Usually, the control method with voltage and current PI regulators in synchronous rotating frame is applied to three-phase voltage source PWM rectifier. It is easy to generate inrush current during startup period. A slow ramp reference current is commonly used to achieve the soft starting, but not quite effective. The paper first analyzed the cause of inrush current and obtained the shortcomings of...
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...
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...
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