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In this paper, a new control method for distribution static compensator (DSTATCOM) using artificial neural networks (ANN) instead of the conventional direct controller is presented. A feedforward three-layer neural network is adopted to control the output compensating currents. This is accomplished by producing the appropriate switching patterns of the IGBTs. A backpropagation algorithm trains this...
The DC-link voltage pumping-up phenomenon is analyzed for a series active voltage regulator in the paper. In order to avoid DC-link voltage pumping-up, a phase shift compensation strategy is proposed, and the relationship between the source overvoltage ratio, load power factor, phase shift angle and compensation voltage provided by the inverter is presented in detail. Taking a series active voltage...
The doubly salient permanent magnet (DSPM) motor is a novel type of AC brushless machine and it offers advantage of high power density, wide speed range and simple structure. To improve the reliability and fault-tolerant performance, a new dual-channel 12/8-pole DSPM motor speed-adjustable system is proposed in this paper. With the comprehensive introduction for the proposed redundant DSPM motor,...
Toothless permanent magnet (PM) machines with Halbach magnet array and normal one are studied comparatively in this paper. First of all, the analytic model is established for these two kinds of PM machines, then, their magnetic field distributions, magnitudes of magnetic flux at different locations are analyzed, laying emphasis on their different magnetic field variations along with the magnet thickness...
Active power filter (APF) is an effective solution to the compensation of power quality problems, especially harmonics. To achieve better performance, the control method is crucial for APF. Currently, there are many control schemes available for APF, which may be classified as two types: one needs harmonics detection from load current, while the other does not need harmonics detection but does need...
Based on the separation of the fundamental parts and harmonics parts of a voltage waveform, this paper presents a novel scheme for a large-volume high-performance programmable voltage disturbance source (PVDS). The purposed equipment uses a serial main circuit to reduce the current flowing through the switches and increase the volume of the system. The system has a high stability and precision with...
In the distributed AC supply system without control interconnection, the parameters unbalance because of nonuniformity between the unit inverters is inevitable. The supplier unit is difficult to share power properly. Based on the digital control inverter with instantaneous capacitor-current feedback, the affection to power sharing of the filter inductance and equivalent line impedance are analyzed...
Based on the improved model of nonlinear time-varying electric arc resistance, the power supply system model of electric arc furnace (EAF) is established in Matlab/power system blockset, which is used to investigate voltage flicker problem. A flexible power supply strategy is presented, in which static synchronous compensator (STATCOM) is applied to mitigate the voltage flicker produced by EAF. The...
Unified power quality conditioner (UPQC) has the function of improving voltage supply, compensating load reactive power, suppressing harmonic current and increasing power factor; however, tradition control method has a certain extent limitation for such multiple input, multiple output, close coupling nonlinear issue. Artificial neural networks (ANN) can deal with data for multiple objectives learning...
Emitter turn-off (ETO) thyristor based static synchronous compensator (STATCOM) is one of the promising flexible AC transmission system (FACTS) technologies, and it is gaining more popularity in utility grids. A 4.5 MVA ETO based STATCOM failed two ETO devices as over-voltage protection triggered AC connector and disconnected the STATCOM from AC grid supply. This paper presents the investigation of...
Control strategy of model reference adaptive control (MRAC) based on radial basis function neural network (RBFNN) online identification is proposed, and a controller is also designed. Which in accordance with the characteristics of the electrode system in electric arc furnace as the high nonlinearity, time-variant, uncertainty and multivariable input and output coupling. The validity of control strategy...
Direct torque control (DTC) can produce quick and robust response, but it has the problems of large torque ripples and inconstant inverter switching frequency. This paper introduces a modified direct torque control based on the space vector pulse width modulation (SVPWM) for interior permanent magnet synchronous motor (IPMSM) drive without a speed sensor. Two PI controllers regulate the flux and torque...
In this paper, the main reason causing rotor position detection error in sensorless BLDC motor drives that the band pass filters are employed to get the zero-crossings of back-emf is presented. The effects on commutation that result from the rotor position detection error are investigated, and the simulation results are given. The correction method is suggested, and the experimental results are provided
A position sensorless control scheme of permanent magnet synchronous machines (PMSM) without saliency is proposed. The rotor position angle of PMSM is estimated by a novel sliding mode observer over a wide speed range including flux-weakening region. A feedback of the equivalent control is applied in the sliding mode observer. Compared to conventional sliding mode observers (SMO), the proposed approach...
The main strategy in analyzing the motion of a rigid body is to split the motion into the linear motion of the CM and the angular motion of the body about its CM. This is because all particles composing the body show the same relative angular motion about the CM. In other words, one can describe the motion of the rigid body as a whole rather than those of the particles individually. The physical characteristics...
This paper presents results of application of novel methods of synchronized pulse width modulation (PWM) to the open-end winding induction motor drives on the base of dual two-level voltage source inverters, with both single and separate DC voltage sources. The proposed control algorithms provide synchronous symmetrical control of the motor phase voltage, together with elimination of the common-mode...
The dynamics is improved to approximately first order by using peak current mode control, because of reducing a system order due to the inductor current is restrained as a control signal. However, the voltage mode control is mainly used, and there are few applications for which peak current mode control is used in VRM application. This paper presents, the transient response of VRM with peak current...
This paper proposed uniform hybrid system models for second-order DC-DC converters working under continuous current mode. Contrast to the averaged and linearized models, no approximation is introduced to the modeling. The direct method of Lyapunov is used to analyze stability of the system and a new sliding mode control strategy is derived from the analysis. Simulation and experiment results are presented...
This paper presents a novel current control technique called 'variable bias current control (VBCC)' developed to minimize the power consumption of active magnetic bearings (AMB) used in turbomolecular pumps. Initially, the mathematical model of the AMBs and the TMP are derived to obtain the simulation model of the system. Then, the effectiveness of bias current on energy consumption is investigated...
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