Generalized adaptive phase-shifted PWM for single-phase seven-level cascaded H-bridge multilevel inverters

Eroğlu, Fatih; Arslan, Ali Osman; Kurtoğlu, Mehmet; Vural, Ahmet Mete

doi:10.1109/iceee2.2018.8391291

Cited by 8 publications

(5 citation statements)

References 18 publications

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“…Combining with ( 15) and ( 16), the harmonic envelope H m can also be expressed as From (17) and Fig. 5, the harmonic envelope Hm depends on the included angle 〈h m i , h m ex, i 〉 , which is related to the displacement angle ϕi.…”

Section: A Harmonic Suppression Principlementioning

confidence: 99%

“…The employment of an extra battery-fed power cell to overcome the limitation is proposed in [16]. Moreover, [17] defines the behavior for the CHB converter operations in the invalid region. To improve the method aforementioned, a discontinuous pulsewidth modulation (D-PWM) is presented to simultaneously work with the VA. PS-PWM technique [18].…”

Section: Introductionmentioning

confidence: 99%

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Sideband Harmonic Suppression Analysis Based on Vector Diagrams for CHB Inverters Under Unbalanced Operation

Jiao

Wang

et al. 2024

IEEE Trans. Ind. Electron.

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Sideband harmonics of the cascaded H-bridge (CHB) inverters, modulated by the phase-shifted pulsewidth modulation (PS-PWM) scheme, will appear with unbalanced dc voltages or/and modulation signals in different cells. The linear controller to suppress the output voltage distortion is destined to be ineffective due to the non-linear characteristic of sideband harmonics. Focus on this problem, this article proposes a closed-loop harmonic suppression method by adjusting the displacement angles for the N-cells CHB inverter, with the help of vector diagrams and the Hessian Matrix. This method can achieve the suppression of the harmonic distortion around any multiplicative switching frequency. Displacement angles are adjusted continuously in real-time. No complicated trigonometric function calculations and optimization algorithms are required. The harmonics suppression mechanism is also revealed from a vector synthesis point of view. The superior harmonic performance achieved by the proposed method is verified by the simulation and experiment results.

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Section: A Harmonic Suppression Principlementioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Sideband Harmonic Suppression Analysis Based on Vector Diagrams for CHB Inverters Under Unbalanced Operation

Jiao

Wang

et al. 2024

IEEE Trans. Ind. Electron.

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“…In [18]- [20], the offline variable PS-PWM is further investigated addressing the possibility to operate the CHB inverter with mismatched modulation indices and different dc voltages. The variable PS-PWM technique is improved by introducing the sampling-time harmonic control in [21]- [22]. However, these techniques depending on inverse trigonometric functions are complicated, and the computational complexity grows and even has no analytical solution as the number of cells grows.…”

Section: Introductionmentioning

confidence: 99%

The Closed-Loop Sideband Harmonic Suppression for CHB Inverter With Unbalanced Operation

Jiao

Wang

et al. 2022

IEEE Trans. Power Electron.

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For N-cells cascaded H-bridge (CHB) inverters based on unipolar double frequency phase-shifted pulse-width modulation (PS-PWM), the harmonic spectrum of the output voltage is degraded and difficult to be suppressed with unbalanced conditions (different dc voltages and/or modulation indices). This article proposes a closed-loop harmonic suppression scheme based on the PS-PWM technique, and the scheme is implemented with the "dq frame" to adjust cleverly the displacement angles of the triangular carriers online. The proposed method can effectively restrain harmonic magnitudes without the limitation of cells number and does not require complicated trigonometric function calculations. This method is not only applicable for all the operational conditions, but also suitable for harmonic optimization of different demands. Moreover, the principle of the symmetrical sideband harmonic suppression is also revealed. The effectiveness of the proposed method is verified by a down-scale test platform of the single-phase CHB inverter. 1

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“…A variable phase‐angle PS‐PWM for three‐cell CHB‐MLI is proposed for unbalanced operating conditions in Marquez et al, and this work has been extended to larger number of cells in Marquez et al In both works, V dc and m a differences have been considered, yet they have not come up with a solution in DC fault conditions and the cases in which the proposed method fails to calculate phase angles. Both of these problems have been solved in Eroglu et al, still, only three‐cell case has been considered. In addition, a PV connection has not been conducted in none of the three papers given above.…”

Section: Introductionmentioning

confidence: 99%

Harmonic reduction under unbalanced operating conditions of PV‐connected cascaded H‐bridge multilevel inverters using fault tolerant adaptive phase‐shifted pulse width modulation

Eroğlu

Kurtoğlu

Arslan

et al. 2019

Int Trans Electr Energ Syst

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Summary Balanced operating conditions of photovoltaic (PV)‐connected cascaded H‐bridge multilevel inverters (CHB‐MLIs) require equal number of series and parallel arrays, equal amplitude modulation indices, and same environmental conditions such as temperature and irradiance for each H‐bridge (cell). Unbalanced operating conditions arise when at least one of these requirements are not met and/or a DC fault occurs. Phase‐shifted pulse width modulation (PS‐PWM) is the most widely used technique for CHB‐MLIs. However, under unbalanced operating conditions, harmonics that appear around the effective switching frequency (fsw) of each cell fail to eliminate each other when PS‐PWM is used, and consequently, undesired harmonics are generated at the multiples of fsw on the output voltage of CHB‐MLI. In this paper, a fault tolerant adaptive phase‐shifted pulse width modulation (FTA‐PS‐PWM) method is proposed for any number of cells to overcome this problem. For this reason, a mathematical representation of the harmonics appearing around the multiples of fsw on the output voltage of CHB‐MLI is suggested. In this analysis, on/off instants of the power semiconductors are investigated in frequency domain for a single carrier period. Based on derived formulations, phase angle of each cell is calculated at each sampling time using DC voltages and amplitude modulation indices of all cells in FTA‐PS‐PWM. In order to validate the usefulness of the proposed switching strategy, a three‐phase, PV‐connected CHB‐MLI is established in simulation environment and a prototype of a single‐phase CHB‐MLI is built. It is shown that FTA‐PS‐PWM reduces output voltage harmonics effectively in unbalanced operating conditions including DC faults for different number of cells. Moreover, FTA‐PS‐PWM is also compared with previous methods in the literature and compliance of output harmonics with international standards is examined for various cases. The results reveal that FTA‐PS‐PWM generally provides better results in terms of individual harmonics and total harmonic distortion of output voltages of CHB‐MLI and satisfies the requirements of the standards.

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Generalized adaptive phase-shifted PWM for single-phase seven-level cascaded H-bridge multilevel inverters

Cited by 8 publications

References 18 publications

Sideband Harmonic Suppression Analysis Based on Vector Diagrams for CHB Inverters Under Unbalanced Operation

Sideband Harmonic Suppression Analysis Based on Vector Diagrams for CHB Inverters Under Unbalanced Operation

The Closed-Loop Sideband Harmonic Suppression for CHB Inverter With Unbalanced Operation

Harmonic reduction under unbalanced operating conditions of PV‐connected cascaded H‐bridge multilevel inverters using fault tolerant adaptive phase‐shifted pulse width modulation

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