Sherif M. Dabour

A simple CB-PWM technique for five-phase matrix converters including over-modulation mode

This paper presents a simple carrier-based PWM (CBPWM) technique to control a three-phase to five-phase matrix converter (3×5 MC). The proposed technique is based on the indirect configuration of the matrix converter in which the three to five-phase matrix converter is modeled as three-phase rectifier followed by a five-phase inverter. With this representation, CBPWM technique is suggested to control both stages in both linear and over-modulation modes. Using the proposed modulation technique, the maximum possible voltage transfer ratio (VTR) of the converter in the linear and over-modulation modes is achieved. The proposed modulation technique is modeled using Matlab/Simulink software and the overall system algorithms are compiled to a real time system based on DS1104 controller. A sample of the obtained experimental results is presented to support the viability of implemented three to five-phase matrix converter with the proposed modulation technique.

Open-circuit fault detection of five-phase voltage source inverters

This paper proposes an approach to detect the open-circuit faults in a five-phase voltage source inverter. The inverter is modulated with space vector PWM. However, the proposed approach is independent of the modulation technique. The open-circuit faults under study are single transistor open-circuit, single inverter switch open-circuit, double-transistors open-circuit, double-switches open-circuit, and inverter leg/legs open-circuit. The proposed approach is based on measuring the terminal voltages of the inverter and compares it with the output voltages of the analytical model. These measurements require one cycle from the output voltage to detect the fault and to identify the fault location. Simulation and experimental results of common open-circuit faults occurred in the five-phase voltage source inverter are given. Results and analysis lead to extract rules for different fault conditions. These rules help for both fault detection and localization.

Control of five-phase induction motor under open-circuit phase fault fed by fault tolerant VSI

Five-phase induction motor drive systems have gained much popularity due to the numerous advantages that they offer when compared to their three-phase counterparts. In principle, the supply to five-phase drive system is given from five-phase voltage source inverter (VSI). In this paper, a fault-tolerant control strategy for five-phase VSIs has been suggested. The conventional five-phase inverter consists of only five legs. The proposed strategy forces the faulty phase to connect to the midpoint of the DC-link via the additional dc-bus midpoint inserting Thyristors. The proposed inverter provides tolerance to both short-circuit and open-circuit faults of the switching devices. The performances of the post-fault as well as the normal pre-fault operation are discussed. The fault tolerance of the inverter is verified using vector control of a five-phase induction motor. The complete control scheme is implemented in real-time using digital signal processor (DS1104) for a prototype 1.5 hp motor. Experimental results of the proposed drive verify the proposed control scheme.

Performance of a three-to-five matrix converter fed five-phase induction motor under open-circuit switch faults

Multiphase machines are conventionally fed from voltage source inverters (VSIs) with bulky dc-link capacitors, which represent a technical drawback in high power medium voltage applications. Alternatively, multiphase matrix converters can offer a direct 3-phase to n-phase conversion without the need for this bulky storage element. Most of the available literature investigates multiphase matrix converter under healthy conditions. This paper introduces the performance of a five-phase induction motor fed by a three-to five-phase matrix converter (3×5 MC) under fault conditions. The indirect space vector modulation (ISVM) technique is employed to modulate the converter switches and the entire system is controlled using open-loop Volts/Hz control. The given study is limited to open-circuit switch faults due to gate failures with different bidirectional switch arrangements employed. A simulation case study using Matlab/Simulink is carried out to investigate the performance of the whole system under different fault scenarios, and results are compared with the healthy case.

Indirect space-vector PWM technique for three to nine phase matrix converters

This paper develops indirect space vector modulation technique for a three- to nine-phase matrix converter. The proposed technique is based on the double-stage configuration in which the matrix converter is modeled as three-phase rectifier followed by a nine-phase inverter. Both rectifier and inverter stages are controlled using space-vector modulation technique. In the rectifier stage, the modulation is based on input currents space-vectors. However, the modulation of the inverter stage is based on output voltages space-vectors. Two different schemes are suggested to control the inverter stage. In the first scheme, only largest space vectors are used in order to achieve maximum voltage transfer ratio of the inverter stage. In the second scheme, eight active vectors are used in each sector in order to minimize the switching stresses and to give a sinusoidal output voltage. It is observed that, using the first scheme results in achieving a higher value of the maximum overall voltage transfer ratio. However, the output voltages contain a significant amount of lower order harmonics. On the other hand, sinusoidal output voltages with a reduced value are obtained by second scheme. A sample of the obtained simulation results is presented to support the viability the proposed technique.

Common-mode voltage reduction of matrix converter fed seven-phase induction machine

This paper introduces space vector modulation (SVM) schemes for reducing the common mode voltage (CMV) of a direct three-to seven-phase matrix converter (3×7 MC) fed a seven-phase induction motor. The proposed techniques are based on the indirect SVM (ISVM) in which the 3×7 MC can be modeled as a three-phase rectifier followed by a seven-phase inverter. The CMV reduction is achieved by suggesting three-ISVM schemes that are capable of reducing the peak CMV of the MC by 20%, 38% and 50% respectively compared with the conventional modulation strategy. The selection criterion to the suitable voltage space vectors and their proper arrangement within the switching cycle are described. The proposed ISVM schemes are assessed by simulating a direct 3×7 MC fed seven-phase IM using Matlab/Simulink. The effect of different modulation schemes on the motor phase currents and output torque is also investigated.

Generalized SVM technique for multiphase current source inverters

This paper introduces a generalized Space-Vector-Modulation (SVM) technique for n-phase Current-Source-Inverters (CSIs), where n is an odd number. Generally, for an n-phase CSI there are n² possible switching-states. Each state generates an output current space-vector. The resulted vectors are n(n − 1) active with (n − 1)/2 levels and n zero-vectors. These vectors are mapped in (n − 1)/2 subspace planes. Each plane is divided into 2n sectors with (n − 1) active- and n zero-vectors. The first-plane is called the fundamental-plane or αβ, while the others are called auxiliary-planes which are labeled by x<inf>1</inf>y<inf>1</inf>·x<inf>2</inf>y<inf>2</inf>··· etc. Two SVM methods are proposed based on the selected vectors. Moreover, generalized equations to determine the dwelling-times in both methods are proposed based on the ampere-second balance concept. In order to check the validity of the generalized-technique a case study for five-phase CSI fed an inductive-load is presented. A sample of simulation results is obtained to confirm the presented technique effectiveness.

A new dual series-connected Nine-Switch Converter topology for a twelve-phase induction machine wind energy system

This paper introduces a new transformerless converter topology for Multiphase-Based Wind Energy Conversion Systems (WECSs). In this topology, a twelve-phase induction generator is integrated to the grid using dual Nine-Switch Converters (NSCs) connected in series forming a high voltage cascaded dc-link. For this generator phase number, this topology reduces the total number of semiconductor devices in the machine side converter by 25% than conventional topologies, where four three-phase two-level voltage source converters are typically needed. Moreover, it offers a high ac-dc boosting capability, which facilities a transformerless system operation. The twelve-phase induction generator can be regarded as dual symmetrical six-phase windings with a spatial displacement of 30°. Therefore, each NSC controls each six-phase winding set. The dc-link midpoint balancing is achieved based on controlling the (x−y) current components of the two winding groups. The proposed topology and its control system are analyzed and simulated under different operating cases using MATLAB/SIMULINK.

A new fifteen-switch inverter topology for two five-phase motors drive

The multimotor drives supplied from reduced switch-count converter topologies are potentially employed in different applications such as EVs/HEVs and traction systems. Much research work has been done to investigate the feasibility of different series/parallel-motor connections in an appropriate manner while being supplied by a single Voltage Source Inverter (VSI). In this paper, a new Fifteen-Switch Inverter (15-SI) topology for supplying two independent five-phase motors is proposed. This topology can be considered as an extension to the well-known nine-switch converter topology, which can be used to independently control two three-phase motor drives. First, the proposed inverter topology and its mathematical model are presented. Then, three carrier-based Pulse Width Modulation (PWM) schemes to control the converter and their operational constraints are investigated under Common Frequency (CF) and Variable Frequency (VF) modes of operation. The proposed system is validated by simulating the proposed 15-SI feeding two identical five-phase induction motors using Matlab/Simulink.