[show abstract][hide abstract] ABSTRACT: This article proposes a novel direct space vector modulation (DSVM) strategy that can restrict the common-mode voltage of a three-phase-to-three-phase matrix converter and maintain sinusoidal input/output waveforms, as well as a unity power factor at the input side. The proposed control method has been developed using active, non-zero space vectors instead of zero space vectors. A new space vector modulation table is also presented with the space vector rearrangement. One advantage of the proposed method is a 42% reduction of the peak value of the common-mode voltage besides the lower harmonic components compared to the conventional DSVM method. Furthermore, the maximum voltage transfer ratio is unaffected by the proposed method. Simulation and experimental results are shown to validate the advantages of the proposed DSVM method.
International Journal of Electronics - INT J ELECTRON. 01/2012; 99(1):1-14.
[show abstract][hide abstract] ABSTRACT: Common-mode voltage (CMV) is responsible for overvoltage stress to the winding insulation and bearing damage of an ac motor. High dv/dt of CMV raises leakage currents, which can cause serious problems such as motor damage and elec- tromagnetic noise to the equipment installed near the converter. This paper proposes two modulation strategies for indirect matrix converters that substantially eliminate CMV. The first method is developed by using the suitable couple of nonzero space vectors instead of zero space vectors in the inverter stage. The maximum voltage transfer ratio of this method is unaffected and remains 0.866. The second one, which is useful for low-voltage operation, is approached by choosing the medium and the lowest positive line- to-line input voltages in the rectifier stage to generate the dc-link voltage and by placing suitable zero space vectors in the inverter stage. In the second method, the maximum voltage transfer ratio is 0.5. Both methods can mitigate the peak value to 42%. In addition, while the first method provides the same performance to the con- ventional method, the second method can reduce significantly the harmonic components of line-to-line output voltage. Simulation and experimental results are shown to verify the effectiveness of the proposed methods. Index Terms—AC/AC converter, common-mode voltage (CMV), direct matrix converter (DMC), indirect matrix converter (IMC), matrix converters (MCs), space vector pulsewidth modulation (SVPWM).
IEEE Transactions on Industrial Electronics - IEEE TRANS IND ELECTRON. 01/2012; 59(1):129-140.
[show abstract][hide abstract] ABSTRACT: In this paper, the control of a stand-alone doubly fed induction generator (DFIG)-based wind power conversion system with unbalanced and nonlinear loads is investigated. Under these load conditions, the quality of stator voltage and current waveforms of the DFIG is strongly affected due to the negative and distorted components, reducing the performance of other normal loads connected to the DFIG. To tackle this problem, the control strategy is comprehensively developed in both rotor-side converter (RSC) and load-side converter (LSC) of the DFIG. The LSC is used as an active power filter to compensate for unbalanced and distorted stator currents whereas the RSC is developed to fully eliminate unbalanced and harmonic voltages at the point of common coupling. The proposed compensation method is based on current controllers in either the RSC or the LSC, which employ a proportional integral plus a resonant controller. These current controllers are controlled in the positive synchronous reference frame so that the rotor current and stator current are directly regulated without decomposing sequential components. Analytical issues on how to eliminate unbalanced and distorted components in the stator voltage and current are also described in this paper. To verify the effectiveness of the proposed control strategy, experimental results with 2.2-kW DFIG topology are presented and discussed in the paper.
IEEE Transactions on Industry Applications - IEEE TRANS IND APPL. 01/2012; 48(1):199-210.
[show abstract][hide abstract] ABSTRACT: An input filter is necessary for a matrix converter (MC) system to improve the input current quality with low harmonic components, as well as to reduce the input voltage distortion supplied to the MC. However, the input filter's characteristics make the input power factor (IPF) obtained at unity only in the presence of high output loads, and the IPF degrades significantly under light-load conditions. In this paper, we propose a new direct space vector modulation (DSVM) method to achieve the required displacement angle between the input voltage and input current of the MC. A new switching strategy is introduced based on the maximum compensated angle. Then, power factor compensation algorithms using the new DSVM method to achieve the maximum IPF are presented, in which compensation algorithm I is based on using the input filter and power supply parameters to estimate the optimal compensated angle. Compensation algorithm II is subsequently proposed using a proportional-integral controller to overcome drawbacks presented in compensation algorithm I. Simulation and experimental results are shown to validate the effectiveness of the proposed compensation algorithms.
IEEE Transactions on Industrial Electronics 02/2011; · 5.17 Impact Factor
[show abstract][hide abstract] ABSTRACT: This paper proposes a new control strategy of effective fifth and seventh harmonic elimination in the stator output voltage at the point of common coupling for a stand-alone doubly fed induc- tion generator (DFIG) feeding a three-phase diode rectifier. This load regularly causes such harmonic distortions, which harmfully affect the performance of other loads connected to the DFIG. In order to allow the DFIG to deliver a pure sinusoidal stator output voltage, these harmonics must be rejected. The proposed elimina- tion method is investigated based on the rotor current controller employing a proportional integral and a resonant controller, which is implemented in the fundamental reference frame. In this frame, both positive seventh and negative fifth voltage harmonic can be eliminated by using only single resonant compensator tuned at six multiples of synchronous frequency in the rotor current controller. The control scheme is developed in the rotor-side converter for the control and operation of the DFIG. Simulations and experimental results with 2.2-kW DFIG feeding a nonlinear load are shown to verify prominent features of the proposed control method. Index Terms—Doubly fed induction generator (DFIG), nonlin- ear loads, resonant controller, stand-alone system, wind turbine system. NOMENCLATURE
IEEE Transactions on Power Electronics 01/2011; 26(9):2662-2675. · 4.08 Impact Factor
[show abstract][hide abstract] ABSTRACT: In this paper, a new Z-source inverter (ZSI) topology is developed to improve a voltage boost ability of ZSI. Some more inductors and diodes are added into the impedance network of the conventional ZSI. The modulation methods that have been developed in the conventional ZSI can be easily utilized in the proposed ZSI. The voltage boost ratio becomes much higher compared with the conventional ZSI under the same shoot-through duty ratio. In addition, the proposed ZSI can reduce the voltage stress on Z-source capacitor and inverter-bridge significantly because a smaller shoot-through duty ratio is required for high voltage boost ratio. Theoretical analysis of the proposed topology is investigated and the improved performances are validated by both simulation study and experimental results.
[show abstract][hide abstract] ABSTRACT: This paper presents an improved predictive current control (PCC) strategy for unbalanced stand-alone doubly-fed induction generator (DFIG) based wind power systems. The proposed control scheme predicts an appropriate average rotor voltage vector to eliminate the rotor current errors in the following switching period. The identified rotor voltage vector is then applied to the rotor-side converter (RSC) by using space-vector modulation (SVM) with constant switching frequency. To improve control performance, a compensation method for time delay is adopted. The whole control algorithm is performed in the RSC to achieve the desired control output, i.e., compensation for the stator voltage imbalance. The proposed PCC was tested by both simulations and experiments with 2.2kW DFIG feeding an unbalanced load to demonstrate the excellent steady-state performance as well as the extremely fast dynamic response of the proposed current controller.
Energy Conversion Congress and Exposition (ECCE), 2010 IEEE; 10/2010
[show abstract][hide abstract] ABSTRACT: The k-nearest neighbour (k-NN) rule is applied to diagnose the conditions of induction motors. The features are extracted from the time vibration signals while the optimal features are selected by a genetic algorithm based on a distance criterion. A weight value is assigned to each feature to help select the best quality features. To improve the classification performance of the k-NN rule, each of the k neighbours are evaluated by a weight factor based on the distance to the test pattern. The proposed k-NN is compared to the conventional k-NN and support vector machine classification to verify the performance of an induction motor fault diagnosis.
International Journal of Electronics. 09/2010; 97(9):1071-1081.
[show abstract][hide abstract] ABSTRACT: This paper develops a harmonic compensation approach for the stator output voltage of a stand-alone doubly fed induction generator (DFIG) feeding a nonlinear (diode rectifier) load. This load type is characterized by a nonsinusoidal stator voltage consisting of severe harmonic components, fifth and seventh ones, which deteriorate the performance of other loads connected to the DFIG. The aim of the proposed compensation method is to eliminate these harmonics in order for the DFIG to deliver a pure sinusoidal stator voltage. To this end, the proposed compensation method is investigated in the fundamental synchronous rotating reference frame based on a proportional integral (PI) plus a resonant current controller, which is tuned at sixth resonant frequency. Therefore, the proposed control scheme has capability of eliminating both fifth and seventh harmonics without decomposing 5th negative sequence and 7th positive sequence components of the measured rotor current. The whole control scheme is implemented in the rotor-side converter (RSC). The proposed method was tested by simulations and experiments with 2.2kW DFIG feeding a nonlinear load to verify the feasibility and effectiveness in terms of harmonic compensation performance.
[show abstract][hide abstract] ABSTRACT: This paper proposes an improved harmonic elimination strategy for the stator output voltage of a stand-alone doubly-fed induction generator (DFIG) feeding a nonlinear load. The proposed elimination method is investigated based on a proportional plus multi-resonant current controller using the stationary reference frame, which is implemented in the rotor-side converter. The aim of the current controller is to achieve the satisfactory performance of rotor currents regulated at harmonic frequencies in order to eliminate fifth and seventh harmonic components in the stator output voltage. As a result, the control scheme allows the DFIG to deliver a pure sinusoidal stator voltage. The proposed control scheme was tested by experiments with 2.2kW DFIG feeding a nonlinear load to verify the feasibility and effectiveness in terms of harmonic compensation performance.
[show abstract][hide abstract] ABSTRACT: This paper presents an approach of sparse matrix converter (SMC) using Z-source network. The SMC is implemented by connecting a controllable rectifier and the traditional inverter through a Z-source network. The Z-source can produce any desired output voltage by controlling the shoot-through time. Compare to the traditional three-phase SMC, the three-phase Z-source SMC has the same number of switches, however, this topology extends output voltage range. In this paper, the new modulation algorithm is applied for the rectifier stage to generate a constant local average dc-link voltage. The input power factor is nearly unity in the whole operating system. Analysis, simulation and experimental results are provided to demonstrate advanced features of three-phase Z-source SMC.
[show abstract][hide abstract] ABSTRACT: This paper proposes a novel control method for operation of a DFIG-based wind generator under unbalanced stand-alone loads, connected directly with stator terminal of the generator. The effect of unbalance condition at loads causes torque pulsations on generator and the stator voltage unbalance that degrade the dynamic behavior of control system. To eliminate the negative sequence components existing in generated stator voltages, the proposed compensation approach is developed based on the coordinated control of rotor-side controller (RSC) of the DFIG system. The main concern of this paper is the use of hybrid current controller (HCC), consisting of a proportional integral (PI) controller plus a resonant (R) compensator. For the sake of improvement, the HCC is executed in the positive synchronous rotating reference frame without considering decomposition of positive and negative sequence components of current values. Simulation is executed using PSIM, and experimental results are also shown in the paper to demonstrate the feasibility and efficiency of the proposed control method.
Industrial Electronics, 2009. ISIE 2009. IEEE International Symposium on; 08/2009
[show abstract][hide abstract] ABSTRACT: This paper proposes an adaptive carrier-based pulse width modulation (PWM) for four-switch three-phase inverter. The balanced output currents are guaranteed by this proposed method instead of voltage oscillations across two DC-link capacitors. The linear over-modulation can be easily obtained with this new approach. Simulation and experimental results are shown to validate the feasibility of the proposed method.
Industrial Electronics, 2009. ISIE 2009. IEEE International Symposium on; 08/2009
[show abstract][hide abstract] ABSTRACT: This paper is to present a new space vector pulse width modulation (PWM) algorithm for four switch three phase inverter (FSTPI) fed induction motor under DC-link voltage imbalance. By using reasonable mathematical transform, space vector PWM (SVPWM) technique for FSTPI under DC-link voltage imbalance or ripples have been solved, which is based on the establishment of basic space vectors and modulation technique in similarity with six-switch three-phase inverters. This approach has a very important sense to solve hard problems for FSTPI under DC-link voltage imbalance, for example ensuring the required voltage for undermodulation mode and overmodulation mode 1 and 2, extended to six-step mode. Matlab/Simulink is used for the simulation of the proposed SVPWM algorithm for undermodulation, overmodulation mode 1 and 2. This SVPWM approach is also validated experimentally using DSP TMS320LF2407a in FSTPI-IM system.
Industrial Technology, 2009. ICIT 2009. IEEE International Conference on; 03/2009
[show abstract][hide abstract] ABSTRACT: This paper presents a novel DTC-SVM method for matrix converter fed induction motor. The advantages of DTC method are combined with the advantages of the matrix converter based on the direct space vector modulation (DSVM) technique. This proposed method provides a precious input power factor control capability beside the high control performances. Furthermore, the FFT spectrum analysis of the input current shows the better harmonic contents as compared to the conventional DTC method. The simulation results of 5HP induction motor control at both steady state and transient state are shown to verify the effectiveness of the proposed method.
Industrial Technology, 2009. ICIT 2009. IEEE International Conference on; 03/2009
[show abstract][hide abstract] ABSTRACT: This paper presents induction motor control system operation using matrix converter based on the controller area network (CAN).
The hardware control system is designed with dual microcontrollers which communicate to each other by a dual-port RAM. The
advantages of matrix converter are utilized with the CAN network on the field oriented control method of induction motor.
The performances of the motor control fully guarantee the system stability and the successful data communication by network.
The experimental results are given on 5Hp induction motor to verify the effectiveness and feasibility of the control system
Emerging Intelligent Computing Technology and Applications. With Aspects of Artificial Intelligence, 5th International Conference on Intelligent Computing, ICIC 2009, Ulsan, South Korea, September 16-19, 2009, Proceedings; 01/2009
[show abstract][hide abstract] ABSTRACT: This paper presents an alternative direct space vector modulation (DSVM) method of matrix converter for a voltage transfer ratio less than 0.5. The principles of selecting suitable switching configurations based on a new sectors definition are described. Switching table for the alternative DSVM method is developed with the controllable input power factor. There are some advantages of the alternative DSVM method which are deeply considered as compared to the conventional DSVM method: lower total harmonic distortion (THD) of line-to-line output voltage and peak value of common-mode voltage reduced by 42%. Low switching loss is reduced considerably by a minimum number of switching commutations. Simulation and experimental results are shown to verify the effectiveness of the proposed DSVM method.
[show abstract][hide abstract] ABSTRACT: Since the input filters characteristics design for matrix converter system: to reduce the high harmonic components at the main power supply current and to improve the input voltage distortion for matrix converter, the unity power factor at the main power supply side is only achieved at the high output load and decreases greatly at the light load conditions. This paper proposes a new direct space vector modulation (DSVM) method to achieve the required displacement angle between input voltage and input current of matrix converter. Firstly, this proposed DSVM method introduces new switching patterns for the controllable input power factor of matrix converter and secondly, the power factor compensation method is then suggested. Simulation results with inductive load (RL) and 5-HP induction motor are shown to validate the effectiveness of the proposed method.
[show abstract][hide abstract] ABSTRACT: The user interface to achieve IEC 61400-25 communication for virtual wind power plant is developed. The information from wind power plant is obtained by MMS service. And also, the data communication between the local control center and the remote control center is achieved by Web service. MMS service is implemented with the aid of MMS Ease-lite and Visual C++. MMS server detects and saves the information of the wind generator such as element type, the temperature, the speed and the voltage needed for the virtual system. MMS client can receive the information for control and monitoring through MMS service. And MMS client can be a Web service server when the remote control center asks to send the data. The proposed user interface enables to access the data related with the wind power plant through the Ethernet at anyplace.
Control, Automation and Systems, 2008. ICCAS 2008. International Conference on; 11/2008