Matrix Converter Prototype Research Articles

Performance evaluation of GaN FET-based matrix converters with dv/dt filters for variable frequency drive applications

This paper evaluates the dv/dt performances of the motor input terminal fed by a gallium nitride (GaN) field effect transistor (FET) matrix converter for variable frequency drive applications. To limit the high dv/dt caused by the fast switching operation of GaN devices, a dv/dt filter is employed. With the dv/dt filter, the input terminal voltage can meet the standards suggested by National Electrical Manufacturers Association. On the other hand, when a GaN FET matrix converter and an electric motor are connected by a long cable, the parasitic impedance of the cable varies. This impedance mismatch results in voltage reflection (VR), and this VR causes a large surge voltage with severe ringing at the motor input terminal. Even in this case, the dv/dt filter effectively restricts the dv/dt of the voltage applied to the electric motor. Frequency response results are obtained through the transfer functions of the filter according to the applied position. Experiments are carried out using a 220 V/60 Hz induction motor and a GaN FET-based matrix converter prototype. The dv/dt filter performance with two positions and cable lengths of 5 m and 25 m is evaluated by comparing the obtained experimental results with the frequency response.

Investigation of The impact of Unbalanced and Non-sinusoidal Supply Voltages on Converters.

In this paper two input current modulation strategies for matrix converters are experimentally analyzed under two different supply conditions: sinusoidal unbalanced voltages and non-sinusoidal balanced voltages. Both strategies use the Space Vector Modulation (SVM) technique in order to control the matrix converter accordingly to the input and output constraints. Strategy A modulates the input currents keeping the corresponding space vector in phase with the input voltage vector. Strategy B operates in order to keep the input current vector in phase with the positive sequence fundamental component of the input voltage vector. A comparison between the two strategies is made in terms of the reduction of the input current disturbances due to the unbalanced and non sinusoidal voltage on the grid. It is found that a dynamic current modulation strategy, independent of the voltage disturbances such as Strategy B, is more effective for the reduction of the RMS value of input current disturbances. The validity of the theoretical investigation i.e. the effectiveness of the current modulation strategy conforms to experimental tests result carried out on a matrix converter prototype.

Four-Step Current Commutation Strategy for a Matrix Converter Based on Enhanced-PWM MCU Peripherals

In this paper, an efficient implementation of the four-step current commutation technique for controlling bidirectional power switches in a Matrix Converter (MC) is proposed. This strategy is based on the enhanced pulse width modulation peripheral included in the C 2000 Delfino 32-bit microcontroller of Texas Instruments. By tuning the algorithmic parameters contained in this module, the four-step commutation process is carried out on the Microcontroller Unit (MCU) without overloading the full complex processor and avoiding the use of additional special hardware such as Field-Programmable Gate Arrays (FPGA) or Complex Programmable Logic Devices (CPLD) when controlling the MC. The algorithm is implemented on the TMS320F28379D MCU and operationally validated on an MC prototype, where the functionality of the proposal is demonstrated.

Improvement in Power Quality of Matrix Converter Interfaced Wind Turbine Emulator

We have seen that the nominal power of single Wind Energy Converter Systems has been steadily growing up and reaching power ratings close to 10 MW. In the power conversion stage, we found that the medium-voltage power converters are replacing the conventional low-voltage back-to-back topology. Due to this reason the Matrix Converters interfaced have appeared as a promising solution for Multi-MW WECSs due to their characteristics such as modularity, reliability and the capability to reach high nominal voltages. In 2009-10, the country imported 159.26 million tons of crude oil which amounts to 80% of its domestic crude oil consumption and 31% of the country's total imports are oil imports. The growth of electricity generation in India has been hindered by domestic coal shortages and as a consequence, India's coal imports for electricity generation increased by 18% in 2010. So in this paper I try to develop fuzzy-logic based control strategy to capture maximum wind energy and reduce harmonics for proposed wind generation system and then develops fuzzy control for indirect matrix converter under steady-state and dynamic conditions. With these assumptions finally try to validate the proposed wind generation system in simulation environment to validate the developed control algorithms under various balanced /unbalanced conditions. Finally evaluate the performance of the developed wind generation system and its controls under various balanced/unbalanced wind conditions. During investigating details the robustness of the steady-state and dynamic performance of the developed system under various balanced/unbalanced conditions using simulation software I presents the experimental performance evaluation of the developed matrix converter prototype with wind emulator.

Research on Output Voltage Modulation of a Five-Level Matrix Converter

The matrix converter (MC) is a direct ac-ac power converter without an intermediate dc link. It has several attractive features, such as high power density, four-quadrant operation, and bidirectional power flow. However, the application of MCs in high-voltage and high-power systems is still limited by the device voltage levels. It is well known that the multilevel power converter technology can be a solution to enhance the voltage rating and improve harmonic performance in many applications. Therefore, an application of a multilevel topology based on a direct ac-ac power converter is proposed in this paper. This paper first introduce the topology structure, the switching pattern grouping method, and the proposed output voltage modulation method for a five-level capacitor clamped multilevel matrix converter (5LMC). Amplitude coefficient adjustment is also introduced as a part of modulation procedure to simplify the duty cycles calculation. Simulation from MATLAB/Simulink is given to demonstrate the theoretical work. Experimental results from a five-level matrix converter prototype are presented to validate the theoretical findings.

Design and Dimensioning of Essential Passive Components for the Matrix Converter Prototype

The continuous popularity of the research in the area of the matrix converter control theory has been supported by steady technological improvements. It is still common to use discrete semiconductor switches in an anti-serial connection, even though some integrated solutions have been presented by various vendors already. Furthermore, recently experimental all-in-one matrix converter power modules based on reverse blocking transistors were introduced. However, this development has not eliminated the need of the protection circuit and other passive components in the converter’s power part. This article strives to describe design procedure for one kind of the matrix converter protection circuits and the design of the input filter for the 3x3 matrix converter prototype.

Experimental Validation of Vector Control of a Matrix Converter Fed Induction Generator for Renewable Energy Sources

Grid integration of induction generators driven by renewable energy sources requires power electronic converters to transform the grid voltage into an output voltage of appropriate magnitude and frequency. This paper presents an experimental validation on vector control of a matrix converter fed induction generator. Operation of a matrix converter is presented. The principle of vector control for induction generators is described. A matrix converter prototype 3 kW, 230 V, 50 Hz is developed. Rotor speed and flux are digitally controlled by 32-bit microcontrollers TMS320F28069. The experimental results confirm viability of the proposed control method.

Common-Mode Voltage Elimination in a Three-to-Five-Phase Dual Matrix Converter Feeding a Five-Phase Open-End Drive Using Space-Vector Modulation Technique

This paper proposes a space-vector modulation (SVM) algorithm for a five-phase open-end winding motor drive system, fed by a dual nonsquare matrix converter (MC). The input to each of the MCs (MC-1 and MC-2) is a three-phase utility grid, and the output is a five-phase with variable voltage, variable frequency capability. The major contribution of this paper is the elimination of the detrimental common-mode voltage (CMV) that appears across the motor winding. In addition, the proposed SVM allows for a unity power factor at the input side, while boosting the output phase voltage by up to 150% of input. This paper presents a comprehensive analysis, to obtain the expression for the SVM modulating signals that are used to generate the switching pulses for the MC. To verify the idea, a modular, reconfigurable 5-kW MC prototype, feeding a five-phase induction motor is built. The control algorithm is implemented on a dSPACE-1006 platform. The test shows that the CMV is successfully eliminated from the motor winding. Other results (i.e., current and voltage waveforms) are also found to be in very close agreement with the theoretical prediction and MATLAB simulation.

Realization of SVM Algorithm for Indirect Matrix Converter and Its Application in Power Factor Control

Compared with AC-DC-AC converter, matrix converter (MC) has several advantages for its bidirectional power flow, controllable power factor, and the absence of large energy storage in dc-link. The topology of MC includes direct matrix converter (DMC) and indirect matrix converter (IMC). IMC has received great attention worldwide because of its easy implementation and safe commutation. Space vector PWM (SVM) algorithm for indirect matrix converter is realized on DSP and CPLD platform in this paper. The control of the rectifier and inverter in IMC can be decoupled because of the intermediate dc-link. The space vector modulation scheme for IMC is discussed and the PWM sequences for the rectifier and inverter are generated. And a two-step commutation of zero current switching (ZCS) in the rectifier is achieved. Input power factor of IMC can be changed by adjusting the angle of the reference current vector. Experimental tests have been conducted on a RB-IGBT based indirect matrix converter prototype. The results verify the performance of the SVM algorithm and the ability of power factor correction.

A Novel Space Vector Technique for the Direct Three-level Matrix Converter

This study proposes a novel Direct Torque Control (DTC) method for the Direct Three level Matrix Converter (DTMC), which uses both the input phase voltage vectors (short vectors) and the input line voltage vectors (long vectors). The problem of voltage imbalance at the input filter capacitance due to the use of the short vectors is addressed with an additional voltage hysteresis comparator. With the errors of torque, flux, sin Ψ and the neutral point voltage, an Optimum Switching Table (OST) is designed for the DTMC. The OST generates the necessary switching signals for the DTC of the DTMC. The DTMC topology with the modified ISVM technique reduces the THD at the output. The proposed DTMC Indirect Space Vector pulse width Modulation (ISVM) technique uses the idea of multilevel inverter SVM technique along with the proposed neutral current balancing strategy for generating the firing pulses. The switching loss model for the DTMC is developed and the performance of the DTMC is compared with that of the Conventional Matrix Converter (CMC). The performance of the proposed DTC technique for the DTMC is evaluated through simulation to explain the reduced torque ripple characteristics. To validate the proposed DTMC ISVM technique, a 3 kVA direct multilevel matrix converter prototype was developed.

A Three-phase to three-phase matrix converter prototype

This paper presents some implementation details of a three-phase to three-phase matrix converter prototype. The bidirectional semiconductor switches were built using discrete IGBTs and fast diodes. Design aspects such as protection against overvoltage and short-circuit, commutation process of bi-directional switches, and input filter are addressed in this paper.

Design and Dimensioning of Essential Passive Components for the Matrix Converter Prototype

The continuous popularity of the research in the area of the matrix converter control theory has been supported by steady technological improvements. It is still common to use discrete semiconductor switches in an anti-serial connection, even though some integrated solutions have been presented by various vendors already. Furthermore, recently experimental all-in-one matrix converter power modules based on reverse blocking transistors were introduced. However, this development has not eliminated the need of the protection circuit and other passive components in the converter's power part. This article strives to describe design procedure for one kind of the matrix converter protection circuits and the design of the input filter for the 3 × 3 matrix converter prototype.

Matrix Converter Based on Asymmetric Regular Sampling Method SPWM Control Strategy

In this paper, the Matrix converter can be viewed as AC-DC-AC converter, the asymmetric regular sampling method SPWM control technique is applied in the control of matrix converter, the asymmetric regular sampling method SPWM control strategy of matrix converter, 48 allowed switch combinations and Four-Step Current Commutation method is presented. Based on Matlab/simulink the simulation of the matrix converter with such strategy is carried out. Inductive load simulation is carried out on the matrix converter prototype. The simulation results verify the workability of the asymmetric regular sampling method SPWM strategy for matrix converter.

A Research on Space Vector Modulation Strategy for Matrix Converter Under Abnormal Input-Voltage Conditions

The matrix converter is a single-stage ac-ac power conversion device without dc-link energy storage elements. Any disturbance in the input voltages will be immediately reflected to the output voltages. In this paper, a modified space vector modulation strategy for matrix converter has been presented under the abnormal input-voltage conditions, in terms of unbalance, nonsinusoid, and surge (sudden rising or sudden dropping). By using the instantaneous magnitude and phase of input-voltage vector to calculate the voltage modulation index and input-current phase angle, this modified modulation strategy can eliminate the influence of the abnormal input voltages on output side without an additional control circuit, and three-phase sinusoidal symmetrical voltages or currents can be obtained under normal and abnormal input-voltage conditions. The performance of the input currents is analyzed when the matrix converter uses different modulation strategies. Some numerical simulations are presented to confirm the analytical results. Tests are carried out on a 5.5-kW matrix converter prototype. Experimental results verify the validity of the proposed strategy.

EMI modeling method of AC-AC power converters

This paper presents a new model for simulation of Electromagnetic Interference (EMI) in power converters. Despite the fact that a Matrix Converter (MC) has been selected, such methodology can be applied to other converter topologies. The EMI model relies on a combination of time and frequency domain techniques in order to not only reduce the computational complexity but also to avoid convergence problems. Common Mode (CM) leakage current, which lays basically in A band (10kHz to 150kHz), is simulated and such results are compared with those obtained from the MC prototype showing a good concordance in terms of peak value.

Predictive Control of an Indirect Matrix Converter

This paper presents the implementation of a predictive control scheme for an indirect matrix converter. The control scheme selects the switching state that minimizes the reactive power and the error in the output currents according to their reference values. This is accomplished by using a prediction horizon of one sample time and a very intuitive control law. Experimental results with a 6.8-kVA indirect matrix converter prototype are provided in order to validate the proposed control scheme. The converter uses standard digital signal processor operating at a sampling frequency of 20 mus. It is shown that the idea of controlling this converter topology with a predictive approach can be implemented simply and input currents with unity power factor and a total harmonic distortion lower than 5% can be obtained.

Large-Signal Model for the Stability Analysis of Matrix Converters

The interest in using the matrix converter (MC) for motor drive applications and energy conversion systems is steadily increasing due to its main advantage of performing a direct coupling between two three-phase alternating current sources without the need of an intermediate direct current bus. This characteristic, together with the presence of inductance-capacitance input filters and the feedforward compensation of the input voltage variations, might yield unstable operation in electrical drives. In this paper, a theoretical analysis of MCs based on a large-signal model is presented with the aim to show which parameters may affect the stability and to explain the reason of this phenomenon. The theoretical analysis is supported by several experimental tests carried out on an MC prototype

Theoretical and Experimental Investigation on the Stability of Matrix Converters

Matrix converters perform a direct coupling between two ac sources without the need for energy storage components. This characteristic, together with the presence of L-C input filters and the feedforward compensation of the input voltage variations, may determine unstable operation as the power delivered to the load exceeds a limit value. In this paper, a theoretical analysis of the stability of matrix converters is presented with the aim of predicting possible critical operating conditions. It is verified that all of the system parameters affect more or less the stability, including the delay introduced by the digital controller and the power losses. The theoretical analysis is supported by numerical simulations and experimental results carried out on a matrix converter prototype.