Search

This paper proposes the space vector pulse width modulation technique of a matrix converter topology with three phase fixed grid input and seven phase variable voltage variable frequency output. Voltage source inverter is generally used for feeding multi-phase drives. Multi-phase matrix converter is proposed in this paper as a new solution for feeding multi phase system. The paper develops the complete space vector algorithm of the proposed multi-phase matrix converter topology. The developed space vector model suggests 221 possible switching combination vectors. After imposing mathematical constraints the number of switching combinations reduce to 2184 active and three zero vectors. The complete space vector PWM algorithm is developed in the paper. The feasibility of the proposed algorithm is proved using analytical, simulation and real-time approach.

This paper proposes space vector pulse width modulation (SVPWM) technique for a direct matrix converter with five-phase input and three-phase output. This topology of matrix converter is developed exclusively for feeding three-phase stiff grid system with five-phase variable input supply. One of the presumed applications is wind electric energy generation system. The paper presents the complete space vector model of the five-to-three-phase matrix converter topology. The major breakthrough of the proposed control scheme is the enhanced input to output voltage transfer ratio. The maximum output phase voltage can go up to 104.4% of the input phase voltage in the linear modulation range and hence can act as a boost converter. The space vector model yields 215 total switching combinations, which reduce to 125 states (for SVPWM implementation) considering the imposed constraints, out of which 120 are active and 5 are zero vectors. However, for SVPWM implementation only 30 active and 5 zero vectors can be used. A generalized formula for maximum modulation index for n-phase input and 3-phase output is also formulated. The SVPWM algorithm is presented in the paper, and the viability of the proposed solution is proved using analytical, simulation and real-time approach.

This paper proposes a new four-quadrant adjustable speed drive (ASD) system based on an induction motor fed by a three-phase quasi-Z-source direct matrix converter (QZSDMC). The quasi-Z-source (QZS) network is used to overcome the limitation of the voltage gain of the traditional direct matrix converter (DMC). The QZSDMC can provide a buck-boost operation by controlling the shoot-through (ST) duty ratio. In addition, this paper presents a four-quadrant speed control method based on vector control technique which is able to control the motor speed from zero to the rated speed with the full load torque during motoring and regenerating operation modes. The simulation results validate the proposed QZSDMC based adjustable speed drive system. The proposed ASD system overcomes the voltage gain limitation of the traditional direct matrix converter with improved efficiency and higher readability compared to the traditional back-to-back converter configuration.

In this paper, a predictive torque control (PTC) algorithm is introduced for controlling an induction motor (IM) fed by a bidirectional quasi Z-source inverter (BQZSI). A torque, stator flux and capacitor voltage magnitudes control algorithm evaluates a cost function, based on a simple discrete models of the IM and the BQZSI, for each BQZSI available switching state. The voltage vector with the lowest torque, a stator flux and capacitor voltage magnitude errors is selected to be applied in the next sampling interval. The proposed PTC algorithm, with its single structure, can control both sides of the BQZSI to optimize the motor performance with an extremely simple and versatile control algorithm and without any dynamic response limitation caused by the cascaded control structure. A high degree of flexibility is obtained with the proposed control technique due its online optimization algorithm. This paper proposed a new adjustable speed drive system based on a three-phase BQZSI feeding an induction motor. Where, the interesting advantages of the PTC algorithm are combined by the advantages of one of the most interesting power electronics converters, the BQZSI. Simulation results for a 4 kW IM are presented to validate the new proposed electrical drive system.

Model predictive control has emerged as a very powerful method for controlling of electrical energy. One of the major advantages for this control is the performance of the power converters become more better comparing with the traditional modulation control techniques. In this paper, a model predictive control is used to drive a three phase grid connected Quasi-Z-Source Inverter (qZSI) to improve the performance of the three phase injected output current. This technique uses a model of the qZSI and capacitor voltage, input inductor current and AC three phase output load currents to predict the behavior of the measured parameters. The resulting closed-loop system achieves high dynamic performance for all controlled parameters. The total system has been analyzed, simulated by using MATLAB/SIMULINK program then implement by using dSPACE 1103 to prove the idea.

This paper proposes a new three-phase ac-ac converter topology based on the Z-source concept and the conventional direct matrix converter (DMC), it is called quasi-Z-Source direct matrix converter (QZSDMC). It could provide buck-boost function and make the role of frequency changer. Compared with the traditional ac-dc-ac converter, it uses fewer devices and realizes direct ac-ac power conversion, so as to have higher efficiency and better circuit characteristics. Compared with the traditional direct matrix converter, it provides wider voltage regulation range and improves input-output voltage transformation ratio. The proposed converter is tested as a grid connected converter for interfacing renewable energy sources. The circuit topology, operating principle, control method and simulation results are given to verify the feasibility of the proposed converter.

This paper proposes technique to obtain ten-phase output from three-phase input supply system using special and novel transformer connection. With the proposed supply system, pure ten-phase sine-wave voltage/current is obtained that can be used for the motor testing purposes and obtaining dual five-phase supply. The proposed transformer connection yield ten-phase output while the input is grid supplied three phases. Another application area of such transformer can be ten-phase power transmission and rectifier system. In this work an open ended five-phase induction motor is run on the sinusoidal output of a three-to-ten-phase converting transformer. Also two five-phase induction motors with single sided connection are supplied from the proposed transformer connection. Analytical results are validated using simulation and finally by experimental approach.

This paper presents a dual-mode controller to improve the performance of maximum power point tracking in grid-connected photovoltaic inverters. Most of grid-connected PV applications require a controllable active/reactive power generation. The proposed method employs both of the load angle and the inverter modulation index into two control modes: Active power mode, and reactive power mode. Such technique enables an efficient and flexible active/reactive power control beside MPPT function using a single-stage VSI. A simulation model is developed for the overall system to investigate the performance of the proposed dual-mode controller. Furthermore, the controller is designed and implemented using a digital signal processor (DSP). Algorithms are configured on a fixed point DSP TMS320F2812. Moreover, the controller is simulated in MATLAB/Simulink environment and is experimentally investigated using a breadboard built especially for the case study. The results show good dynamic and steady-state performances.