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Voltage lift technique is a popular method widely used in electronic circuit design. However the voltage increases stage by stage along arithmetic progression. But with a super-lift converter, the output increases stage by stage along a geometric progression. Thus it effectively enhances the transfer gain in power series. This paper presents the development of PI control capable of providing good...
This paper proposes a predictive output voltage controller for the phase-controlled series-parallel resonant converter. The objective of this controller is to enhance closed loop system robustness and dynamic performance compared to conventional PI control. First, the converter non-linear large signal behavior is linearized using a state feedback based scheme. Consequently, the converter preserves...
Dynamic Voltage Restorer (DVR) is a practicable and economical way to ensure the energy quality of power system. Under the study of the control strategy that combine grid voltage feed-forward control with the load voltage and capacitor current double closed-loop feedback control, the traditional Proportion Integration (PI) controller in feedback control is analyzed, and a novel control strategy combining...
The existing power transmission capabilities can be flexibly controlled and enhanced with the help of new technology called Flexible AC Transmission System (FACTS). This power electronics based technology can be used individually or in co-ordination with other controllers. Static VAR Compensator (SVC) is a shunt connected FACTS device, used for voltage control and for reactive power compensation....
A novel topology with a bi-directional DC/DC for stand-alone wind power system is adopted, which can maximize the battery life by monitoring and controlling its state of charge(soc) and charge/discharge process. According to the atmospheric conditions, the state of charge of the battery and the load conditions, six possible operation modes of the bi-directional DC/DC are also expounded. This paper...
This paper presents a simple and effective control scheme for a stand-alone Wound Rotor Induction Generator (WRIG) feeding non-linear and unbalanced loads under varying rotor speed and load conditions. Synchronous Reference Frame (SRF) method is used for the estimating the harmonic and the negative sequence components from the load current without the need to decompose load current into sequential...
A power shaping stabilizing control strategy for DC power system feeding constant power loads is applied in this paper to analyze the system stability. The principle of the power shaping strategy is described and comparison with general PI control strategy is carried out. Simulations and experiments proved the effectiveness of the power shaping stabilizing control strategy.
In this paper, a novel grid voltage feed forward control strategy under d-q rotating frame is proposed based on three-phase grid-connected voltage source inverter (VSI) with LCCL filter to suppress the grid current harmonics caused by the grid voltage distortion. Although the control strategy of grid-connected inverter with LCCL filter has many advantages, this control strategy fails to control grid...
Abstract-On the basis of traditional PI control for DC-side voltage of Active Power Filter(APF), a parameter self-adjusting fuzzy PI control method is designed in this paper. In order to adjust the parameter itself, it is can be used fuzzy control rules to control the fuzzy output variables according to fuzzy input variables. The simulation results show that the method has smaller overshoot, faster...
As the exact mathematical model of the active power filter (APF) is quite difficult to determine, especially when the load and the parameters are changing. Applying the ordinary proportional-integral (PI) controller with constant parameters cannot achieve ideal results. This paper introduces the adaptive fuzzy PI controller to the voltage control of the APF, which can achieve better tracing result...
This paper mainly discuss the performance of proportional-integral (PI), traditional sliding mode (SM) and dynamic sliding mode (DSM) control for Buck converter. After building the model of Buck circuit, the three control algorithm are designed. When the reference voltage or load of converter change suddenly, the simulation results illustrate that steady state error of DSM does not exceed 0.15% even...
In this paper, comparative study of three algorithms of digital PI control, that is, conventional PI control, offset control and modified PI control, is presented. Conventional PI control is subjected to numerical error because the gain must be small in order to move zero of the control to output transfer function to low frequency. To prevent this undesired issue, authors have already proposed novel...
To improve the voltage quality of the power supply is an important function of the D-STATCOM. A novel voltage control strategy based on active-disturbance rejection control under unbalance voltage conditions is proposed in this paper. The active-disturbance rejection control for D-STATCOM is proposed to overcome the difficulty result from the nonlinear, multivariable and coupling characteristics of...
Power conditioning system (PCS) is an interface between distributed generation and utility grid. It regulates voltage, current and power transmitted from the hybrid direct fuel-cell/turbine (DFC/T) power plant to utility grid. This paper presents a self-adaptive fuzzy PI controller of three phase inverter in PCS for the DFC/T power plant. One of the main tasks of PCS for distributed generations is...
In this paper, a double-loop control scheme is proposed for the VSC-HVDC transmission system connecting two AC grids. A conventional PI controller is used in the outer loop and a current deadbeat controller is presented in the inner loop in order to achieve fast dynamic response, high tracking accuracy and robustness. Cases of two-terminal VSC-HVDC system are developed in MATLAB/SimPowerSystems to...
In this paper, the control approaches of linear proportional-integral (PI) and nonlinear flatness-based estimation for dc link stabilization for fuel cell/supercapacitor hybrid power plants are compared. For high power applications, 4-phase parallel boost converters are implemented with a switching interleaving technique for a fuel cell (FC) converter, and 4-phase parallel bidirectional converters...
This paper introduces a new optimal technique to estimate the PI gains for current regulated inverter control. The PI controller tuning is accomplished using bacterial foraging optimization (BFO) algorithm to reduce voltage and current harmonic distortions and comply with the local grid requirements and interconnection standards. Robust and decoupled active and reactive power control is achieved....
This paper presents a high-performance design of dc-dc switching power converter system, which can deliver a regulated 0–50V and 0–15A output. The full-bridge phase-shift converter is realized with zero voltage switching and UCC3895 IC to achieve higher efficiency and pulse width modulation. For wide range of adjustable voltage output control, a PI gain-scheduling control scheme is proposed and implemented...
This paper presents a DC voltage control analysis for hybrid active power filters (HAPF) under current-mode control scheme. Based on the analysis, it is clearly shown that adding the instantaneous DC voltage control signal as a reactive control parameter is more effective than adding the signal as an active control parameter for the DC voltage control. A control strategy is introduced to improve the...
In wind power generation, phase angle of grid voltage is an important variable for decouple control of inverter connected to grid. When grid fault occurred which seriously affect wind turbine operating performance, such as grid voltage unbalance, voltage drop and so on, it is crucial to lock the phase angle as quickly and correctly as possible for the control. In this paper, a soft phase-locked loop...
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