A Modulation Technique to Reduce Switching Losses in Matrix Converters
ABSTRACT This paper presents a modulation technique based on the generalized pulsewidth-modulation strategy for matrix converters. The proposed technique uses a discontinuous modulation to clamp each output leg of the converter during 120deg of the output voltage period, achieving a reduced number of switchings compared with the traditional modulation techniques. Aside from that, the major attraction of the proposed technique is an additional algorithm that lags the clamping of each output leg of the converter to synchronize it with the peak of the corresponding output current (load current), avoiding high switching losses (switching at high currents). Therefore, this technique reduces the number of switchings as well as guarantees only medium and low current switchings. Simulation and experimental results show the efficiency of the proposed technique.
Article: Generalized Duty-Ratio-Based Pulsewidth Modulation Technique for a Three-to-k Phase Matrix Converter[show abstract] [hide abstract]
ABSTRACT: This paper presents a novel topology for a direct ac–ac power converter, called as the "three-to-k" phase matrix converter. The input to the proposed matrix converter configura-tion is a three-phase fixed voltage and a fixed frequency supply from the grid. The output is a variable voltage and variable frequency ac supply of any number of phases (k phase). However, the discussion is limited here for a k that is equal to odd number of phases. As an example, a "three-to-five" phase matrix converter is utilized for discussion and analysis. This paper also proposes two pulsewidth modulation (PWM) control techniques for the general topology of the "three-to-k" phase matrix converter. This is based on the so-called direct duty ratio PWM (DPWM). In one presented technique, the output voltage is limited to one half of the input volt-age. For the other proposed scheme, the output voltage is enhanced to 78.86% of the input voltage. The proposed control algorithm is validated using simulation and an experimental approach. Index Terms—AC–AC power conversion, direct duty ratio, multiphase, pulsewidth modulation (PWM).IEEE Transactions on Industrial Electronics 01/2011; 58. · 5.16 Impact Factor