Generalized Selective Harmonic Elimination Modulation for Transistor-Clamped H-Bridge Multilevel Inverter

Abstract

This paper presents a simple approach for the selective harmonic elimination (SHE) of multilevel inverter based on the transistor-clamped H-bridge (TCHB) family. The SHE modulation is derived from the sinusoidal voltage-angle equal criteria corresponding to the optimized switching angles. The switching angles are computed offline by solving transcendental non-linear equations characterizing the harmonic contents using the Newton-Raphson method to produce an optimum stepped output. Simulation and experimental tests are conducted for verification of the analytical solutions. An Altera DE2 field-programmable gate array (FPGA) board is used as the digital controller device in order to verify the proposed SHE modulation in real-time applications. An analysis of the voltage total harmonic distortion (THD) has been obtained for multiple output voltage cases. In terms of the THD, the results showed that the higher the number of output levels, the lower the THD due to an increase number of harmonic orders being eliminated.

Harmonic minimization of a single-phase asymmetrical TCHB multilevel inverter based on nearest level control method

“…If a bigger inductance is used, the current THD will reduce, and its waveform will be more close to sinusoidal. By comparing the results with those obtained in [26] using the SHE method for the same number of levels, it was noted that the minimum voltage THD using the SHE method is 6.70%, while in the case of the proposed NLC method, the minimum achieved voltage THD is 5.18%, as shown in Figure 5, which indicates a significant improvement in the voltage THD. Another comparison is made with [19] for the same control method, the same number of levels, but with different asymmetrical MLI topology.…”

Multilevel Inverter: A Survey on Classical and Advanced Topologies, Control Schemes, Applications to Power System and Future Prospects

“…This topology is quite identical to the earlier discussed CHB-MLI topology. However, the significant difference between HCHB and CHB topology are: (i) in HCHB, each H-bridge cell is added with an auxiliary switch for the harmonic profile improvement of output waveforms; (ii) the number of devices required in this HCHB topology is comparatively significantly less in comparison to the CHB topology for the same level of output voltage waveform [158] and (iii) with the operational and switching activities, HCHB topology possesses double RMS output voltage, voltage steps quantity and reduced number of DC sources. However, the major demerit is that it cannot be employed for high voltage applications.…”

Selective Harmonic Elimination Based on Newton-raphson Method for Cascaded H-bridge Multilevel Inverter

“…There are three wellestablished and commercial topologies of multilevel inverters namely, neutral point clamped (NPC), cascaded H-bridge (CHB) and flying capacitor (FC) [1]- [3]. In most topologies, the CHB has attracted special attention as it gives continuous supply to load even if there is fault in any module, thus it is very reliable [4]. In addition, it reduces the number of components used and therefore, the cost of the inverter is less when compared with NPC or FC multilevel inverters.…”

“…The multicarrier sinusoidal pulse-width modulation (SPWM) and space vector modulation (SVM) techniques are considered as high-switching frequency schemes [5], whereas selective harmonic elimination (SHE) technique falls under low-switching frequency group [4], [6]. Multicarrier SPWM exploits only one reference waveform which is compared to the multiple numbers of carriers (normally triangular carriers) covering all the range of reference variation.…”

“…It is computed offline, where the switching angles are properly selected to eliminate the most significant low order harmonics among different level inverters [7]. Various algorithms have been developed to calculate the switching angles such as the Newton-Raphson (NR) method [4], particle swarm optimization (PSO) [8] and genetic algorithms (GA) [9]. The combination of both low and high frequency produces a hybrid modulation method.…”