scholarly journals Predictive Control Method Based on Adjacent Vector Confinement Technique for a Three-Phase AC-DC Matrix Converter with High Efficiency

Electronics ◽  
2019 ◽  
Vol 8 (12) ◽  
pp. 1535
Author(s):  
Eun-Su Jun ◽  
Hoang-Long Dang ◽  
Sangshin Kwak

A model predictive current control method is proposed to reduce switching losses in an AC-DC matrix converter. In the proposed control strategy, several vectors are selected from among all possible switching vectors for a given location of the input current reference. The switching vector that minimizes the cost function is applied to the converter in the next sampling period. The principle of the proposed method involves clamping the selected switches to stop performing the switching operation to minimize the number of switchings in every sampling cycle. The total efficiency of the AC-DC matrix converter under the proposed strategy is 91.2% whereas that of the conventional strategy is 89.7%. In addition, unity-power-factor operation is guaranteed and smooth and sinusoidal waveforms are achieved. Finally, simulation and experimental results are demonstrated to confirm the validity of the proposed control strategy.

Electronics ◽  
2019 ◽  
Vol 8 (6) ◽  
pp. 625 ◽  
Author(s):  
Eun-Su Jun ◽  
So-young Park ◽  
Sangshin Kwak

In this paper, the model predictive current control (MPCC) method using two vectors has been proposed to control output currents of three-phase voltage source inverters (VSIs) with small current errors and current ripples. Also, the proposed method can reduce switching losses by applying the vector pre-selection technique to the MPCC for the VSI. The VSI generates seven voltage vectors to control the output currents, but the proposed method uses four available voltage vectors with one switch, which are classified by the vector pre-selection method clamping one leg and conducting the largest output current among the three legs to reduce the switching losses. In the proposed method, selecting two future voltage vectors among the four voltage vectors and dividing them in a future sampling period are determined by an optimization process. The proposed method results in the lower total loss, better total harmonic distortion (THD), and smaller current errors than the conventional method with half the sampling period of the proposed method due to the optimal process. Simulation and experimental results of the three-phase VSIs are presented in order to verify the effectiveness of the proposed method.


Energies ◽  
2020 ◽  
Vol 13 (5) ◽  
pp. 1159 ◽  
Author(s):  
Zhijian Feng ◽  
Xing Zhang ◽  
Jianing Wang ◽  
Shaolin Yu

Silicon carbide (SiC) devices have excellent performance, such as higher switching frequency and lower switching loss compared with traditional silicon (Si) devices. The application of SiC devices in inverters can achieve higher efficiency and power density. In recent years, the production process of SiC devices has become more mature, but the cost is still several times that of traditional Si devices. In order to balance cost and efficiency, replacing only some of the Si devices with SiC devices in a topology is a better choice. This paper proposed a high-efficiency hybrid active neutral point clamped (ANPC) three-level inverter which has only two SiC devices and the other devices are Si devices. A specific modulation strategy was applied to concentrate switching losses on the SiC devices and reduce the on-state loss through parallel operation during freewheeling intervals. Theoretical efficiency curves and experimental verification of the proposed hybrid scheme with Si-only and SiC-only schemes were carried out.


2012 ◽  
Vol 241-244 ◽  
pp. 636-640
Author(s):  
Wu Wu Tang ◽  
Liang Liang Chen ◽  
Hong Xu Yin ◽  
Hao Dong

This paper developed a mathematical model of three-phase PV grid-connected inverter, and studied the grid-connected current control method based on PI control in synchronous rotating reference frame. Simulation and experimental results from the prototype of 30kW three-phase PV grid-connected inverter proved the correctness and the feasibility of the control strategy, and this grid-connected inverter can operate at the unity power factor state with a nice dynamic performance, and the output current has high sinusoidal and low harmonic content as well as good symmetry.


Energies ◽  
2020 ◽  
Vol 13 (12) ◽  
pp. 3247
Author(s):  
Bowei Zou ◽  
Yougui Guo ◽  
Xi Xiao ◽  
Bowen Yang ◽  
Xiao Wang ◽  
...  

In asynchronous motor direct torque control systems, the power supply using the matrix converter can achieve the effect of direct torque control and also has the advantages of the matrix converter. Nonetheless, direct torque control still has drawbacks in terms of pulsation. In this paper, the characteristics of direct torque control method and its existing problems are analyzed in depth. In view of the shortcomings of torque ripple, an improved scheme of torque tracking control is proposed based on conventional control methods. On the basis of theoretical simulation, DSP and FPGA algorithms are designed respectively in C language and VHDL to implement the proposed control strategy. Finally, a highly integrated experimental platform of matrix converter has been developed to verify the proposed control strategy. The simulation and experimental results verify the correctness and effectiveness of the improved scheme.


Electronics ◽  
2020 ◽  
Vol 9 (8) ◽  
pp. 1325 ◽  
Author(s):  
Yuan Zhu ◽  
Ben Tao ◽  
Mingkang Xiao ◽  
Gang Yang ◽  
Xingfu Zhang ◽  
...  

Two problems can cause control performance degradation on permanent magnet synchronous motor (PMSM) systems, namely, fluctuation of PMSM parameters and the time delay between current sampling and command value update. In order to reduce the influence of these problems, a new current-predictive control strategy is proposed in this article for medium- and high-speed PMSM. This strategy is based on the discrete mathematical model of PMSM. This new control strategy consists of two main steps: First, an integrator is applied to calculate current compensation value; second, the predictive current value is obtained through deadbeat-current predictive method. The stability of predictive control system is also proved in the article. With this deadbeat-current predictive control scheme, the real current can reach the desired value within one control-step. Based on this new current control method, Luenberger observer and phase-locked loop position tracker is applied in this article. Experimental results for 0.4 kW surface-mounted PMSM confirm the validity and excellent performance for parameters fluctuation of new current predictive control.


Author(s):  
Xiaoyuan Wang ◽  
Tao Fu ◽  
Xiaoguang Wang

Brushless DC (BLDC) motors are widely used for many industrial applications because of their high efficiency, high torque and low volume. In view of the problem that the current control method of speed regulation system of BLDC motor has poor control effect caused by fixed parameters of PID controller, an adaptive PID algorithm with quadratic single neuron (QSN) was designed. Quadratic performance index was introduced in adjustment of weight coefficients; expected optimization effect was gotten by calculating control law. QSN adaptive PID controller can change its parameters online when operating conditions are changed, it can also change its control characteristic automatically. Matlab simulations and experiment results showed that the proposed approach has less overshoot, faster response, stronger ability of anti-disturbance, the results also showed more effectiveness and efficiency than the conventional PID model in motor speed control.


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