Milan Darijevic

Two multilevel five-phase open-end winding drive topologies are analysed and compared in this paper. The first topology consists of a five-phase machine and two two-level five-phase inverters, supplied with isolated dc-link voltages. In the second topology three-level and twolevel five-phase inverters are used to supply a five-phase machine. Variation of two dc-link's voltage ratio can lead to different overall number of phase voltage levels in both considered topologies. Dc-link voltage ratio… Show more

Two multilevel five-phase open-end winding drive topologies are analysed and compared in this paper. The first topology consists of a five-phase machine and two two-level five-phase inverters, supplied with isolated dc-link voltages. In the second topology three-level and twolevel five-phase inverters are used to supply a five-phase machine. Variation of two dc-link's voltage ratio can lead to different overall number of phase voltage levels in both considered topologies. Dc-link voltage ratio influence on performance of drive topologies is analysed and experimental verification is provided for the four most suitable drive configurations. Show less

A four-level five-phase open-end winding (OeW) drive topology is introduced in the paper. The drive comprises a five-phase induction machine with open-end stator windings, supplied using two two-level voltage source inverters with isolated and unequal dc-link voltages, in the ratio 2:1. The topology offers the advantages of a modular structure with fewer semiconductor components and has a greater potential for fault tolerance, compared to an equivalent single-sided fourlevel drive. Due to the… Show more

A four-level five-phase open-end winding (OeW) drive topology is introduced in the paper. The drive comprises a five-phase induction machine with open-end stator windings, supplied using two two-level voltage source inverters with isolated and unequal dc-link voltages, in the ratio 2:1. The topology offers the advantages of a modular structure with fewer semiconductor components and has a greater potential for fault tolerance, compared to an equivalent single-sided fourlevel drive. Due to the large number of switching states, development of a suitable space-vector pulse-width modulation (SVPWM) method can be challenging. Hence, this paper examines the implementation of two level-shifted carrier-based modulation (CBPWM) methods. The effect of dead time on the drive performance is discussed and it is shown that simultaneous PWM switching of both inverters can lead to degraded output phase voltage waveforms. Detailed analysis of this phenomenon is presented, a solution is proposed, and the modified modulation techniques are incorporated in an experimental set-up, at first in conjunction with V/f control. Once when the proof-of-concept has been provided, full field oriented control (FOC) is implemented in this OeW drive topology for the first time; detailed experimental testing is conducted and results are reported. Show less

The paper studies pulse width modulation (PWM) techniques for a five-phase multilevel open-end winding drive with two inverters supplied with unequal dc-link voltages, which are in the ratio 2:1. It is shown in the paper that application of in-phase disposition modulation (PD-PWM), often used in multiphase multilevel converters, results in overcharging of the capacitor in the dc-link of the converter intended to operate at the lower dc voltage. The voltage space vector combinations which lead… Show more

The paper studies pulse width modulation (PWM) techniques for a five-phase multilevel open-end winding drive with two inverters supplied with unequal dc-link voltages, which are in the ratio 2:1. It is shown in the paper that application of in-phase disposition modulation (PD-PWM), often used in multiphase multilevel converters, results in overcharging of the capacitor in the dc-link of the converter intended to operate at the lower dc voltage. The voltage space vector combinations which lead to the overcharging are identified and two decoupled modulation techniques which do not activate the troublesome vector combinations are proposed. The performance of the developed modulation techniques is investigated using simulations and an experimental prototype, and the results are presented in the paper. Show less

One approach for post-fault operation of open-end winding drives is analysed in this paper. It is based on drive reconfiguration, with and without additional hardware. It is suitable for a wide range of applications, covering different fault scenarios, from single switch open-fault to more severe faults when several switches or dc-link management system are under fault. Simulation results are provided for three different postfault winding configurations.

Three-phase diode bridge rectifiers that apply suboptimal current injection and active resistance emulation are analysed. Two types of current injection devices (CIDs) are in the focus, and rectifiers with each CID are analysed for two cases of active resistance emulation: one that applies low-frequency filtering of the emulator output, and another that does not. Models that cover both continuous and discontinuous conduction mode are developed. To minimise the input current total harmonic… Show more

Three-phase diode bridge rectifiers that apply suboptimal current injection and active resistance emulation are analysed. Two types of current injection devices (CIDs) are in the focus, and rectifiers with each CID are analysed for two cases of active resistance emulation: one that applies low-frequency filtering of the emulator output, and another that does not. Models that cover both continuous and discontinuous conduction mode are developed. To minimise the input current total harmonic distortion (THD), optimisation is performed, showing that in each case the THD is about the same when the emulated resistance takes its optimal value. The results are experimentally verified on a 1.5 kW rectifier. Show less

In this paper, pulse width modulation (PWM) of a five-phase multilevel open-end winding drive with two inverters supplied with unequal dc-link voltages is analysed. In particular, the effects of dead time on the drive performance are discussed. They are a consequence of PWM switching of both inverters at the same time, which happens to be an inevitable part of the modulation strategy. Detailed analysis of this phenomenon is presented and one possible solution is suggested. This solution is… Show more

In this paper, pulse width modulation (PWM) of a five-phase multilevel open-end winding drive with two inverters supplied with unequal dc-link voltages is analysed. In particular, the effects of dead time on the drive performance are discussed. They are a consequence of PWM switching of both inverters at the same time, which happens to be an inevitable part of the modulation strategy. Detailed analysis of this phenomenon is presented and one possible solution is suggested. This solution is entirely based on changes in the modulation strategy, so that changes in the drive topology and hardware are not required. Show less

A four-level five-phase open-end winding drive topology is introduced in the paper. The system comprises a five-phase induction machine with an open-end stator winding, supplied using two two-level voltage source inverters with isolated and unequal dc-link voltages, in the ratio 2:1. The topology offers the advantages of a modular structure with fewer semiconductor components and has a greater potential for fault tolerance, compared to an equivalent single-sided four-level drive. Due to the… Show more

A four-level five-phase open-end winding drive topology is introduced in the paper. The system comprises a five-phase induction machine with an open-end stator winding, supplied using two two-level voltage source inverters with isolated and unequal dc-link voltages, in the ratio 2:1. The topology offers the advantages of a modular structure with fewer semiconductor components and has a greater potential for fault tolerance, compared to an equivalent single-sided four-level drive. Due to the large number of switching states, development of a suitable modulation method can be challenging. In this paper two carrier-based PWM strategies are developed and the performance is investigated using simulations. Show less

A hybrid three-phase rectifier with switched current injection device and high frequency switching current injection network is analyzed in this paper. The rectifier applies suboptimal current injection. Optimization of the injected current amplitude is performed, resulting in the minimum of the input current THD of 4.36%. Ratings of applied semiconductor devices are derived. Effects caused by finite values of the inductance applied in the current injection network are analyzed. It is shown… Show more

A hybrid three-phase rectifier with switched current injection device and high frequency switching current injection network is analyzed in this paper. The rectifier applies suboptimal current injection. Optimization of the injected current amplitude is performed, resulting in the minimum of the input current THD of 4.36%. Ratings of applied semiconductor devices are derived. Effects caused by finite values of the inductance applied in the current injection network are analyzed. It is shown that increased values of the inductance require reduced amplitude of the injected current, and result in slightly increased values of the input current THD. A new structure of the current injection network that provides filtering of the switching ripple is proposed. The results are experimentally verified on a low-power converter model. Show less

In this paper, suboptimal current injection in three-phase diode bridge rectifiers that apply switching
resistance emulators is analyzed. Two rectifiers are focused, one that applies filtering of the resistance emulator output current, and the other one that does not. Models that cover both the continuous and the discontinuous conduction mode of the rectifiers are developed. Optimization is performed, showing that both of the rectifiers provide about the same performance when the emulated… Show more

In this paper, suboptimal current injection in three-phase diode bridge rectifiers that apply switching
resistance emulators is analyzed. Two rectifiers are focused, one that applies filtering of the resistance emulator output current, and the other one that does not. Models that cover both the continuous and the discontinuous conduction mode of the rectifiers are developed. Optimization is performed, showing that both of the rectifiers provide about the same performance when the emulated resistance takes the optimal value. The results are experimentally verified. Show less