Power Electronics
M. Nabizadeh; P. Hamedani; B. Mirzaeian Dehkordi
Abstract
Background and Objectives: Due to the disadvantages of the traditional AC-DC-AC converters, especially in electric drive applications, Matrix Converters (MCs) have been widely researched. MCs are well-known structures that remove the DC-Link capacitor and provide bidirectional power flow, while also ...
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Background and Objectives: Due to the disadvantages of the traditional AC-DC-AC converters, especially in electric drive applications, Matrix Converters (MCs) have been widely researched. MCs are well-known structures that remove the DC-Link capacitor and provide bidirectional power flow, while also giving the ability to control reactive power flow, which the AC-DC-AC converter lacks. Methods: In this work, Model Predictive Current Control (MPCC) is utilized in conjunction with the MC to provide more versatility and controllability than traditional control methods. The work endeavors to investigate the current control of the MC utilizing the finite control set Model Predictive Control (MPC) approach. Results: Current tracking performance, reactive power control, and switching frequency minimization have been included in the objective function of the controller. Moreover, the results have been compared to the traditional AC-DC-AC converters under similar circumstances. The MC can reduce the switching frequency by 40% compared to the AC-DC-AC converter while maintaining the same current THD value. Additionally, it achieves a 58% reduction in current THD compared to the AC-DC-AC converter at the same average switching frequency. However, in the MC, the mitigation of reactive power and the reduction in switching frequency have opposing effects on the current tracking performance.Conclusion: This work proposes an MPCC method for the MC with an RL load, effectively controlling load current and reactive power. The reduction of switching commutations was also evaluated using different weighting factors in the prediction strategy for both the MC and AC-DC-AC converters. Simulation results demonstrate that the MC outperforms the AC-DC-AC converter in dynamic response and reactive power control.
Power Electronics
P. Hamedani
Abstract
Background and Objectives: To overcome the disadvantages of the traditional two-level inverters, especially in electric drive applications, multi-level inverters (MLIs) are the widely accepted solution. Diode-Clamped Inverters (DCIs) are a well-known structure of multi-level inverters. In DCIs, the voltage ...
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Background and Objectives: To overcome the disadvantages of the traditional two-level inverters, especially in electric drive applications, multi-level inverters (MLIs) are the widely accepted solution. Diode-Clamped Inverters (DCIs) are a well-known structure of multi-level inverters. In DCIs, the voltage balance of the DC-link capacitors and the Common Mode (CM) voltage reduction are two important criteria that should be considered. Methods: This paper concentrates on the current control of 3-phase 4-level DCI with finite control set model predictive control (MPC) strategy. Current tracking performance, DC-link capacitor voltage balance, switching frequency minimization, and CM voltage control have been considered in the objective function of the MPC. Moreover, the multistep prediction method has been applied to improve the performance of the DCI. Results: The effectiveness of the proposed multistep prediction control for the 4-level DCI has been evaluated with different horizon lengths. Moreover, the effect of several values of weighting factors has been studied on the system behavior. Conclusion: Results validate the accuracy of current tracking and voltage balancing in the suggested multistep MPC for the 4-level DCI. In addition, CM voltage control and switching frequency reduction can be included in the predictive control. Decreasing the CM voltage and switching frequency will oppositely affect the dynamic behavior and voltage balancing of the DCI. Therefore, selection of weighting factors depends on the system needs and requirements.
