Space vector pulse width modulation (SVPWM) technique has emerged as a most used modulation strategy for the voltage source inverter (VSI) fed AC motor drives. SVPWM is a method of pre-calculation of switching timing instants for various sections of target output which has options in terms of positioning vectors inside every sampling interval and has six possible patterns (variants) ofthe voltage vectors arrangements in each sector. SVPWM switching patterns, depending on the switching frequency, causes the mechanical vibration and the annoying acoustic noise to the drive system. Avoidance of the main spectral annoyance, harmonics concentration around the carrier frequency and it multiples, is done by increasing the switching frequency to a band which does not contribute mechanical vibrations and acoustic noises. This results in tremendous increase the switching losses. A systematic evaluation of SVPWM switching patterns can guide proper selection of switching frequency and vectors. A Matlab based comparative analysis of all these SVPWM variants in terms of attributes such as total harmonic distortion (THD) in output line voltage, DC bus utilization and the harmonic spread factor (HSF) is reported.

Investigations on harmonic spreading effects of SVPWM switching patterns in VSI fed AC drives

Multiport converters (MPCs), which can have multiple inputs and multiple output (MIMO) ports, have been suggested to integrate a variety of sources (including storage facilities) with diversified loads, thereby guaranteeing both an effective utilization of sources and the uninterruptible supply to loads. MPCs transfer the power between those sources and (active/passive) loads concurrently/independently. The attractive features of MPCs include minimal component count, higher power conversion efficiency, haste response, higher power density, and hence better sizing, combined control point, and bidirectional and soft switching abilities. MPCs are the perfect solution in applications where complex energy distribution prevails, such as renewable energy systems (RES), hybrid electric vehicle (HEV) systems, DC power distribution systems, etc. This paper proposes a hybrid output multiport multilevel converter (HOMPMLC), which is a unique, partially isolated breed of MPC. The HOMPMLC is the multiple input and dual output (MIDO) converter, which can deliver twosome outputs (both AC and DC) from several DC sources. In the HOMPMLC, a new multilevel inverter (MLI) topology, Single stage multilevel DC-link multilevel inverter (SSMLDCMLI), is involved to synthesize a high quality AC output, which utilizes five switches for the seven level improved quality AC output, and the DC output port is accomplished with the help of a forward power converter. The working of the HOMPMLC is studied for a solar photovoltaic system in the MATLAB®Simulink R2016a simulation platform as well as in an experimental investigation involving 4 panels (Schuco MPE-340-AL-01; each 340 Watts).

A new partially isolated hybrid output of multiport multilevel converter for photovoltaic based power supplies

Multiport converters (MPCs), which can have multiple inputs and multiple output (MIMO) ports, have been suggested to integrate a variety of sources (including storage facilities) with diversified loads, thereby guaranteeing both an effective utilization of sources and the uninterruptible supply to loads. MPCs transfer the power between those sources and (active/passive) loads concurrently/independently. The attractive features of MPCs include minimal component count, higher power conversion efficiency, haste response, higher power density, and hence better sizing, combined control point, and bidirectional and soft switching abilities. MPCs are the perfect solution in applications where complex energy distribution prevails, such as renewable energy systems (RES), hybrid electric vehicle (HEV) systems, DC power distribution systems, etc. This paper proposes a hybrid output multiport multilevel converter (HOMPMLC), which is a unique, partially isolated breed of MPC. The HOMPMLC is the multiple input and dual output (MIDO) converter, which can deliver twosome outputs (both AC and DC) from several DC sources. In the HOMPMLC, a new multilevel inverter (MLI) topology, Single stage multilevel DC-link multilevel inverter (SSMLDCMLI), is involved to synthesize a high quality AC output, which utilizes five switches for the seven level improved quality AC output, and the DC output port is accomplished with the help of a forward power converter. The working of the HOMPMLC is studied for a solar photovoltaic system in the MATLAB®Simulink R2016a simulation platform as well as in an experimental investigation involving 4 panels (Schüco MPE-340-AL-01; each 340 Watts). 

The pulse width modulation (PWM) strategy employed in the voltage source inverter (VSI) not only control the magnitude of the output voltage but also the quality. Performance evaluations of such strategies are done in terms of fundamental voltage, total harmonic distortion (THD), switching losses etc. (primary indices) and also in terms of acoustic noise, electromagnetic interference (EMI), harmonic spread factor, distribution of harmonic power etc. (secondary indices). Multilevel inverter (MLI) has become unanimous choice in medium and high power applications due to their superior performance compared to three level inverters. The conventional Sub-Harmonic PWM (SHPWM) scheme and its variations offer the output voltage spectrum with high intensity harmonic components around the switching frequency; it will end with cluster harmonic with high acoustic noise. The first objective of this paper is to investigate harmonic spreading effects of existing multilevel inverter (MLI) strategies. Secondly the developing innovative PWM strategies for MLIs based on modified reference and carrier functions, which were proved for superior the primary indices at three-level VSI. Thorough simulation study of Pulse width modulation strategies such as SHPWM, inverted sine carrier PWM, MWM PWM, third harmonic injection PWM, triplen harmonic injection PWM, analog space vector PWM, trapezoidal PWM and discontinuous PWM for a cascaded multilevel inverter, are presented with results of primary and secondary indices. Hence, the PWM strategies of MLI are evaluated for harmonic spreading effect first time and a guide line for a beginner to select the PWM scheme for MLI fed drive systems is stenciled.

Investigation on Harmonic Spreading Effect of Conventional and Innovative Multi-Level Inverter Control Strategies

A hybrid output multiport converter for standalone loads and photovoltaic array integration

The number of switching per modulation cycle at each level in a multi-level inverter depends on the carrier frequency and the duration that the reference waveform dwells within the level. The variable carrier frequency band (VFCB) approach creates as many clusters as the number of carrier frequencies and consequent deterioration of the harmonic spectrum. Therefore, a new pulse width modulation (PWM) strategy, with the view to ensure that the power devices at all the levels are switched equal number of times, is proposed in this paper. It is designed such that the frequency of the carrier waves is allowed to remain constant for the chosen application while maintaining the number of switching for all devices is same. The MATLAB-based simulation response and its experimental validation are included to highlight the fact that there is a significant enhancement in harmonic power distribution besides contributing to reduce the switching losses and improve the efficiency.

A novel invariable carrier frequency multi-level inverter PWM for balancing switching transitions and better distribution of harmonic power

This paper presents simulation and experimental discussions on conducted electromagnetic interference (EMI) emissions for a single-phase full-bridge sinusoidal pulse width modulated (SPWM) and hybrid pulse width modulated (HPWM) inverters The influences of input dc link voltage, modulation depth and carrier frequency on the conducted noise are studied through ICAP simulation software HPWM method, which effectively reduces the switching losses, exhibits reduced noise level Simulated results are compared and validated with the real-time measurements on a high frequency inverter which is constructed for 100 kHz and tested at SAMEER Lab, Chennai, India Simulation and experimental results are included to highlight the claim that HPWM has reduced noise level

S. Paramasivam

Papers

A novel invariable carrier frequency multi-level inverter PWM for balancing switching transitions and better distribution of harmonic power

A comparative performance evaluation of the conducted emissions in hard switched SPWM and HPWM inverters