Discontinuous PWM Modulation Strategy With Circuit-Level Decoupling Concept of Three-Level Neutral-Point-Clamped (NPC) Inverter

Zhang, Zhe; Thomsen, Ole C.; Andersen, Michael A. E.

doi:10.1109/tie.2012.2227901

Cited by 95 publications

(46 citation statements)

References 30 publications

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“…Therefore, adjusting the duration of equivalent null states can change the discharging current of dc-link capacitors and then balance the dc-link voltages. In specific, the way to realize the balanced dc-link voltages meanwhile keep the MPP operation unchanged in this paper is to use the zero-sequence component injection method to change the switching duration of equivalent null states and consequently the discharging duration of the dc-link capacitors [23][24][25][26][27][28].The illustration of the modified PD modulation strategy with zero-sequence component injection is shown in Figure 10, where the positive zero-sequence component is injected to increase the duration of state (1, 0, 0) and decrease the duration of state (0, -1, -1) and then the upper dc-link voltage can be decreased and meanwhile it will not induce the low order harmonic distortion. Figure 11 illustrates the modulation references with and without the zero-sequence component.…”

Section: Dc-link Voltage Balancing Control Methodsmentioning

confidence: 99%

A Single-Stage Buck-Boost Three-Level Neutral-Point-Clamped Inverter with Two Input Sources for the Grid-Tied Photovoltaic Power Generation

Gao

Chen

2017

Preprint

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This paper proposes a novel single-stage buck-boost three-Level neutral-point-clamped (NPC) inverter with two independent dc sources coupled for the grid-tied photovoltaic (PV) application, which can effectively solve the unbalanced operational conditions generally appeared between two coupled independent PV sources induced by the unequal irradiation and temperature distribution. The proposed control scheme can simultaneously guarantee the maximum power point (MPP) operation of both PV sources and maintain the output waveform quality. Compared to the traditional two-stage PV inverter, the proposed NPC inverter could reduce the PV array voltage requirement and dc-link capacitors' voltage rating, meanwhile show the advantage in operational efficiency. MATLAB simulations and the captured experimental results are presented to show the performance of the proposed three-level inverter.

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Section: Dc-link Voltage Balancing Control Methodsmentioning

confidence: 99%

A Single-Stage Buck-Boost Three-Level Neutral-Point-Clamped Inverter with Two Input Sources for the Grid-Tied Photovoltaic Power Generation

Gao

Chen

2017

Preprint

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“…Like any other NPC inverter, the neutral-point (NP) potential of the SL Zsource three-level inverter must be balanced. Various NP potential balancing methods were proposed for conventional NPC inverters [10][11][12][13][14][15][16][17], most of them alter redundant small vector durations so that the average neutral wire current becomes zero and thus the NP potential is balanced. In [18], a space vector modulated NP potential balancing method is proposed for Z-source three-level Ttype inverter.…”

Section: Introductionmentioning

confidence: 99%

Neutral-point Potential Balancing Method for Switched-Inductor Z-Source Three-level Inverter

Wang¹,

Zhang²

2017

Journal of Electrical Engineering and Technology

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-Switched-inductor (SL) Z-source three-level inverter is a novel high power topology. The SL based impedance network can boost the input dc voltage to a higher value than the single LC impedance network. However, as all the neutral-point-clamped (NPC) inverters, the SL Z-source threelevel inverter has to balance the neutral-point (NP) potential too. The principle of the inverter is introduced and then the effects of NP potential unbalance are analyzed. A NP balancing method is proposed. Other than the methods for conventional NPC inverter without Z-source impedance network, the upper and lower shoot-through durations are corrected by the feedforward compensation factors. With the proposed method, the NP potential is balanced and the voltage boosting ability of the Z-source network is not affected obviously. Simulations are conducted to verify the proposed method.

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“…Three conventional control methods based on DPWM are the 120°DPWM, 60°DPWM, and 30°DPWM [14] [15]. The 60°DPWM control method is shown in Fig.…”

Section: Introductionmentioning

confidence: 99%

“…The three conventional DPWM control methods reduce the switching losses by controlling the switches no switching in certain regions [15]. However, they are commonly ineffective for the neutral-point voltage unbalancing control, especially for the low-frequency oscillation problem.…”

Section: Introductionmentioning

confidence: 99%

A New DPWM Method to Suppress the Low Frequency Oscillation of the Neutral-Point Voltage for NPC Three-Level Inverters

Lyu¹,

Hu²,

Wu³

et al. 2015

Journal of Power Electronics

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In order to suppress the low frequency oscillation of the neutral-point voltage for three-level inverters, this paper proposes a new discontinuous pulse width modulation (DPWM) control method. The conventional sinusoidal pulse width modulation (SPWM) control has no effect on balancing the neutral-point voltage. Based on the basic control principle of DPWM, the relationship between the reference space voltage vector and the neutral-point current is analyzed. The proposed method suppresses the low frequency oscillation of the neutral-point voltage by keeping the switches of a certain phase no switching in one carrier cycle. So the operating time of the positive and negative small vectors is equal. Comparing with the conventional SPWM control method, the proposed DPWM control method suppresses the low frequency oscillation of the neutral-point voltage, decreases the output waveform harmonics, and increases both the output waveform quality and the system efficiency. An experiment has been realized by a neutral-point clamped (NPC) three-level inverter prototype based on STM32F407-CPLD. The experimental results verify the correctness of the theoretical analysis and the effectiveness of the proposed DPWM method.

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Discontinuous PWM Modulation Strategy With Circuit-Level Decoupling Concept of Three-Level Neutral-Point-Clamped (NPC) Inverter

Cited by 95 publications

References 30 publications

A Single-Stage Buck-Boost Three-Level Neutral-Point-Clamped Inverter with Two Input Sources for the Grid-Tied Photovoltaic Power Generation

A Single-Stage Buck-Boost Three-Level Neutral-Point-Clamped Inverter with Two Input Sources for the Grid-Tied Photovoltaic Power Generation

Neutral-point Potential Balancing Method for Switched-Inductor Z-Source Three-level Inverter

A New DPWM Method to Suppress the Low Frequency Oscillation of the Neutral-Point Voltage for NPC Three-Level Inverters

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