Time-Offset Injection Method for Neutral-Point AC Ripple Voltage Reduction in a Three-Level Inverter

Lee, June-Seok; Lee, Kyo‐Beum

doi:10.1109/tpel.2015.2439689

Cited by 87 publications

(41 citation statements)

References 28 publications

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“…It is worth mentioning it is complicated to include a NPC voltage balance variable in the cost function when implementing DBC. Thus, an algorithm for the DC link capacitor voltage balance should be separately applied for proper 3L inverter operation [16][17][18][19][20]. For example, in Reference [16], a calculated zero-voltage sequence was used for neutral-point balancing, while in Reference [18], the time-offset injection method was used for the same purpose.…”

Section: Introductionmentioning

confidence: 99%

Improved Deadbeat FC-MPC Based on the Discrete Space Vector Modulation Method with Efficient Computation for a Grid-Connected Three-Level Inverter System

Alsofyani

Lee

2019

Energies

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The utilization of three-level T-type (3L T-type) inverters in finite set-model predictive control (FS-MPC) of grid-connected systems yielded good performance in terms of current ripples and total harmonic distortions. To further improve the system's performance, discrete space vector modulation (DSVM) was utilized to synthesize a higher number of virtual voltage vectors. A deadbeat control (DBC) method was used to alleviate the computational burden and provide the optimum voltage vector selection. However, 3L inverters are known to suffer from voltage deviation, owing to the imbalance of the neutral-point voltage. We have proposed a simplified control strategy for balancing the neutral point in the FS-MPC with DSVM and DBC of grid-connected systems, not requiring a weighting factor or additional cost function calculation. The effectiveness of the proposed method was validated using simulation and experiment results. Our experimental results show that the execution time of the proposed algorithm was significantly reduced, while its current quality performance was not affected.

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Section: Introductionmentioning

confidence: 99%

Improved Deadbeat FC-MPC Based on the Discrete Space Vector Modulation Method with Efficient Computation for a Grid-Connected Three-Level Inverter System

Alsofyani

Lee

2019

Energies

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“…Furthermore, as electrolytic capacitors have a short life time. There is a decreased reliability of power-conversion systems [3][4][5].…”

Section: Introductionmentioning

confidence: 99%

“…These problems from the AC unbalance become severe when the small capacitors are applied for the DClink. In order to restrict the neutral-point AC ripple voltage, a neutral-point voltage stabilization method using DPWM and the offset injection method are used [5,[16][17][18][19][20][21][22][23][24].…”

Section: Introductionmentioning

confidence: 99%

Design and Control of Small DC-Link Capacitor-Based Three-Level Inverter with Neutral-Point Voltage Balancing

In¹,

Kim

Lee

2018

Energies

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This paper presents a method to improve the quality of input-output currents in a three-level neutral-point clamped (NPC) inverter with small direct current-link (DC-link) capacitor systems. The inverter systems with the small DC-link capacitors have several advantages in terms of cost, volume, life-time, and reliability when compared to inverters that use large DC-link capacitors. However, there are problems with respect to the deterioration of the input current quality and a severe ripple of neutral-point voltage (NPV), which can cause an aggravated output current. To mitigate these issues, an additional circuit is applied for the input current shaping and a compensation algorithm is applied to reduce the ripple voltage of NPV. The effectiveness of the proposed design and control method is verified with various simulation and experimental results.

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“…1, is the most widely studied and used in all types of industrial applications in the range of 2.3-4.16 kV, with some applications up to 6 kV [11]. A vast amount of literature [2,4,6,7,[12][13][14][15][16][17][18][19][20][21][22][23] is mainly dedicated to the modulation strategies and the balancing control of the neutral-point voltage. Seo et al [12] proposed a simplified three-level space vector pulse width modulation (SVPWM) method.…”

Section: Introductionmentioning

confidence: 99%

“…Compared to the DC imbalance problem, the AC imbalance problem is discussed in many papers [2,6,13,15,16,[18][19][20]23]. The frequency of the neutral-point voltage oscillation is 3 times the fundamental frequency, and its amplitude strongly depends on the output current, the power factor, and the value of the capacitor [2,17,24]. A large AC imbalance would cause low-order harmonics and overvoltage stress on semiconductors [2,13,18].…”

Section: Introductionmentioning

confidence: 99%

A simplified hybrid carrier‐based PWM technique for three‐level NPC inverters considering neutral‐point voltage balance

Chen

Huang

et al. 2018

IEEJ Transactions Elec Engng

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An in‐depth analysis and comparison between the virtual space vector pulse width modulation (VSVPWM) method and the space vector pulse width modulation (SVPWM) method is presented in this paper. Compared to SVPWM, VSVPWM can achieve the balance of the neutral‐point voltage for any load over the full range of the inverter output voltage and for all load power factors. Nevertheless, VSVPWM would cause higher dv/dt of output voltages, higher voltage total harmonic distortion, and slower voltage‐balancing dynamic. A detailed analysis on these drawbacks is given. Then, the relationship between the neutral‐point current and the factor k0, which is employed to adjust the ratio of time of application of small vectors in a pair, is studied comprehensively, and a modified zero‐sequence voltage injection method for the two‐level inverter is introduced into the small hexagons of the three‐level space vector diagram. A simplified hybrid carrier‐based pulse width modulation (PWM) method is developed. Compared to VSVPWM, the proposed PWM method is not only easy to implement voltage‐balancing control but also reduces the switching frequencies of the devices and achieves better output voltage spectra and faster voltage‐balancing dynamic. All these benefits of the proposed method are verified through experimentation. © 2018 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.

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Time-Offset Injection Method for Neutral-Point AC Ripple Voltage Reduction in a Three-Level Inverter

Cited by 87 publications

References 28 publications

Improved Deadbeat FC-MPC Based on the Discrete Space Vector Modulation Method with Efficient Computation for a Grid-Connected Three-Level Inverter System

Improved Deadbeat FC-MPC Based on the Discrete Space Vector Modulation Method with Efficient Computation for a Grid-Connected Three-Level Inverter System

Design and Control of Small DC-Link Capacitor-Based Three-Level Inverter with Neutral-Point Voltage Balancing

A simplified hybrid carrier‐based PWM technique for three‐level NPC inverters considering neutral‐point voltage balance

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