Article

# A Modulation Technique to Reduce Switching Losses in Matrix Converters

Fed. Univ. of Pernambuco, Recife

IEEE Transactions on Industrial Electronics (Impact Factor: 6.5). 05/2009; 56(4):1186 - 1195. DOI: 10.1109/TIE.2008.2006241 Source: IEEE Xplore

**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 120

^{deg}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.-
- "Consequently, this method is preferred for theoretical analysis rather than real-time implementation. The second approach is the SVM strategy [11], [12], which is similar to that used by CSRs. This method is a well-known and well-established modulation strategy because of its high performance, relative simplicity, and inherent capability to achieve full control of both output voltage and input power factor. "

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**ABSTRACT:**This study presents an input filter resonance mitigation method for an AC-DC matrix converter. This method combines the advantages of the one-cycle control strategy and the active damping technique. Unnecessary sensors are removed, and system cost is reduced by employing the grid-side input currents as feedback to damp out LC resonance. A model that includes the proposed method and the input filter is established with consideration of the delay caused by the actual controller. A zero-pole map is employed to analyze model stability and to investigate virtual resistor parameter design principles. Based on a double closed-loop control scheme, the one-cycle control strategy does not require any complex modulation index control. Thus, this strategy can be more easily implemented than traditional space vector-based methods. Experimental results demonstrate the veracity of theoretical analysis and the feasibility of the proposed approach. -
- "The essence of one-cycle control lies in the control of duty ratio of the switch so as to making the average value of the switched variable equal to the control reference during one switching cycle [12]. A switch operates according to the switch function k(t) at a frequency f s = 1/ "

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**ABSTRACT:**A novel vector operated one-cycle control matrix rectifier (OCC-MR) is proposed in this paper. Matrix rectifier (MR) is a generalized buck three-phase AC-DC converter with four-quadrant operation capability. MR can also be the front-stage circuit of AC-DC-AC equivalent structure of MC. One-cycle control (OCC) is a nonlinear control technique, which integrates modulation algorithm and control strategy. By applying OCC to current control loop, the OCC-MR achieves balance only in a switching cycle, and realizes unitary input power factor. Furthermore, vector operation of OCC results in minimum switching losses. In order to make up for the insufficiency of OCC on load disturbance suppression, a PID controller is added onto output voltage control to improve load regulation. The OCC-MR features great simplicity, fast dynamic response and good immunity on input disturbance. On the basis of theoretical analysis, a systematic simulation of OCC-MR is implemented by means of Matlab/Simulink. Both static state performance and dynamic state performance of OCC-MR are discussed deeply. The simulation results have proved theoretical analysis of the vector operation of OCC-MR, and the control effects are satisfactory. -
- "To further simplify the implementation of the SVPWM and to get a reduced number of switching and consequently reduced switching losses with improved current spectra, a few other modulation schemes were developed [37]–[41]. These schemes are the variations of the SVPWM. "

##### Article: Generalized Duty-Ratio-Based Pulsewidth Modulation Technique for a Three-to-k Phase Matrix Converter

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**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).

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