Dmitry Baimel

An analytical approach to total harmonic distortion reduction in multi-level inverters

We introduce a novel analytical approach to the evaluation of harmonic content in multi-level inverters. An analytical formula for the phase voltage total harmonic distortion (THD) of any multi-level pulse-width modulation (PWM) signal is introduced. As opposed to conventional THD expression where full spectral knowledge of the signal is required, the proposed formula depends only on fundamental amplitude, inverters voltage level and switching angles. Hence, THD derivation may be significantly simplified. The proposed formula may be applied to evaluate THD of the multi-level output signal. It may be applied to make intelligent decisions as for the choice of various output signal characteristics such as switching frequency, switching angles placement, etc. THD formula can also serve as a cost function to minimize output signal THD while obtaining the desired control over signals fundamental component and lower-order intrinsic harmonics. This way, in cases where multiple solutions exist (e.g., SHE), optimal solution in terms of THD may be obtained.

Simulation of thyristor operated induction generator by Simulink, Psim and Plecs

The paper presents simulation results about thyristor operation of a mains connected induction machine, both as a motor and as a generator. The results were obtained by three different simulation packages, Simulink, Psim and Plecs. The cosimulation options between these programs were checked. The performances of these three packages were compared. The simulation results were validated by real experiments.

Thirteen level cascaded NPC inverter

The paper presents a novel, thirteen level, and cascaded, neutral point clamped inverter. The inverter is modulated by phase disposition (PD) carrier based PWM method. The load of the inverter is a synchronous machine. The simulation results for different voltage levels, different modulation frequencies, and different carrier frequencies are presented. The study of the simulation results helps to define the best operation mode of the inverter for different conditions.

Novel Multilevel Hybrid Cascaded Inverter for High Power Motion Control Systems

The paper presents an analysis of a novel multilevel inverter that can be used in the power modules of motion control systems for soft starting and speed control of high power medium voltage synchronous and induction motors. The inverter is constructed from hybrid cascaded H-bridge cells. The advantages of the proposed inverter upon standard topologies are significant reduction of electrical components and as a result, smaller size and weight. The proposed approach can be extended to any desired number of voltage levels. Extensive simulation results validate the practicability of the proposed inverter. Several aspects, such as Total Harmonic Distortion Factor of the inverter output currents and voltages, harmonic content, and frequency spectrum distribution are studied.

Medium voltage multi-level inverters: Hardware-in-the-loop (HIL) simulations

This paper presents low cost flexible FPGA based HIL simulator and HIL simulation results for 5, 9, and 13-level topologies of medium voltage multi-level inverters that controlled by carrier based pulse-width-modulation (PWM) algorithm. The applications of these inverters can be synchronous or induction motors. The HIL simulation results for each topology are introduced and compared to the conventional simulation results in concept of the load current total harmonic distortion (THD). In addition, the influence of control parameters such as frequency modulation ration, amplitude modulation ration and phase shift between carrier and modulation signals on the load current THD in the HIL simulator is analyzed, and the optimal parameters are introduced.

Novel differential linear electrostatic motor with light weight rotor

The paper proposes a new type of linear electrostatic motor operated on a principle of the electric field effect on dielectric material. The proposed motor has a simple structure that simplifies the production process. Moreover, the motor is designed with very light weight rotor. As a result, the friction and power losses of the motor are reduced. Additional advantage of this motor is that it is not influenced by external magnetic fields. Furthermore, the proposed motor has advanced motion control options that allow precise control of velocity and position profiles. Extensive simulation results of the proposed motor at different operation modes are presented and analyzed. The simulation results demonstrate proposed control methods and show the practicability of the motor.

Phase-shifted Discontinuous Pulse-Width Modulation Methods for Multi-level Inverters Operated in Over-modulation Range

Abstract This article presents combinations of the generic phase-shifted pulse-width modulation method with conventional discontinuous pulse-width modulation methods operated in the over-modulation range. The treated discontinuous methods are the third harmonic injection, Depenbrocks DPWM1, and Ogasawaras DPWM2. The significant advantage of the present approach over the conventional phase disposition pulse-width modulation method is the equal power flow between the H-bridges and the improved distribution of the switching operations number between them. Furthermore, they provide improved linearity in the over-modulation range. The proposed pulse-width modulation methods are analyzed by extensive simulation results. Several aspects, such as the total harmonic distortion factor of the inverter output currents and voltages, harmonic content, frequency spectrum distribution, and switchings number, are studied.

Multi-pulse Rectifiers Feeding H-bridge Inverter

Abstract This article presents a comparative analysis of 12-, 18-, 24-, and 36-pulse rectifier topologies supplying 3-phase three-level H-bridge inverters as active loads. The analysis comprises the total harmonic distortion data of the inverter and grid currents and voltages, including inter-modulation harmonics. This article shows that the rectifier-inverter connection produces inter-modulation harmonics between the grid and inverter frequencies. As a result, inter-modulation and sub-harmonics are present in the grid currents. This article presents an analysis and comparison of these inter-modulation effects for the mentioned topologies. Moreover, it is shown that the inter-modulation effects can be reduced by increasing the capacitance of DC-link capacitors, increasing grid series inductance, and using rectifiers with high number of pulses. The analysis is validated by extensive simulation results.

Five-level H-bridge inverter fed by multi-pulse rectifier

The paper presents two configurations of 5-level, neutral point clamped H-bridge inverter fed by 12-pulse rectifier. In the first configuration, the neutral points of the rectifier and the inverter are not connected and in the second configuration they are connected. Three neutral point voltage balancing methods are proposed for these configurations. Extensive simulation results confirm the effectiveness of the proposed methods. The methods are compared and their advantages and disadvantages are explained.

Generic phase shifted PWM algorithm for thirteen level cascaded H-bridge NPC inverter

The paper presents an original generic phase shifted (PS) PWM algorithm for a thirteen level cascaded H-bridge neutral point clamped inverter. According to the literature, the PSPWM was used only with cascaded 3-level H-bridges. The present algorithm could be used with any type of inverter, while the advantages of the conventional PSPWM algorithm are maintained. The generic PSPWM is applied in the present paper on a 13-level cascaded 5-level H-bridges. The simulation results for the Generic PSPWM are compared to the simulation results of the conventional Phase Disposal (PD) PWM algorithm.