scholarly journals A Virtual Negative Resistor Based Common Mode Current Resonance Suppression Method for Three-Level Grid-Tied Inverter with Discontinuous PWM

Energies ◽  
2020 ◽  
Vol 13 (7) ◽  
pp. 1595
Author(s):  
Qiyu Li ◽  
Hongwei Zhou ◽  
Jiansong Zhang ◽  
Shengdun Zhao ◽  
Jingfeng Lu
Keyword(s):  
Pulse Width ◽  
Pulse Width Modulation ◽  
Neutral Point ◽  
Resonance Problem ◽  
Common Mode ◽  
Zero Sequence ◽  
In Series ◽  
Suppression Method ◽  
Lc Filter ◽  
Control Quantity

The output LC filter of a photovoltaic (PV) string three-level grid-tied inverter that connects the filter capacitor neutral point to dc-link capacitor neutral point can reduce the common-mode (CM) current injected to the grid by letting the CM current circulate within the inverter. However, the internal CM current may resonate because of the existence of the resonant frequency of the internal CM LC circuit. Compared with the traditional continuous pulse-width modulation (CPWM), the resonance can be worse if discontinuous pulse-width modulation (DPWM) is applied, for the zero sequence quantity of DPWM contains more harmonics than that of CPWM. In this paper, a virtual negative resistor based common mode current resonance suppression method for a three-level grid-tied inverter is proposed to overcome the CM current resonance problem in DPWM application. Different positions of the virtual negative resistor in the equivalent CM circuit with different feedback variables are analyzed theoretically. The virtual negative resistor connected in series with the inductor in the equivalent CM circuit is selected to damp the CM current resonance for simplification and damping performance. Different from the implementation in CPWM where a pair of small voltage vectors exist and are used to adjust the CM voltage directly, the proposed method for DPWM application is implemented indirectly by adding the CM adjustment quantity to differential-mode (DM) control quantity with appropriate coefficients. Depending on the sector of DM control quantity in the α β reference frame, the coefficients are calculated using one of three specific voltage vectors. Experimental results are given to demonstrate the effectiveness of theoretical analyses and the proposed method.

scholarly journals A Carrier-Based Discontinuous PWM Strategy of NPC Three-Level Inverter for Common-Mode Voltage and Switching Loss Reduction

Electronics ◽  
2021 ◽  
Vol 10 (23) ◽  
pp. 3041
Author(s):  
Guozheng Zhang ◽  
Yingjie Su ◽  
Zhanqing Zhou ◽  
Qiang Geng
Keyword(s):  
Pulse Width Modulation ◽  
Control Method ◽  
Balance Control ◽  
Neutral Point ◽  
Switching Loss ◽  
Major Drawback ◽  
Common Mode ◽  
Common Mode Voltage ◽  
Zero Sequence ◽  
Zero Sequence Voltage

For the conventional carrier-based pulse width modulation (CBPWM) strategies of neutral point clamped (NPC) three-level inverters, the higher common-mode voltage (CMV) is a major drawback. However, with CMV suppression strategies, the switching loss is relatively high. In order to solve the above issue, a carrier-based discontinuous PWM (DPWM) strategy for NPC three-level inverter is proposed in this paper. Firstly, the reference voltage is modified by the twice injection of zero-sequence voltage. Switching states of the three-phase are clamped alternatively to reduce both the CMV and the switching loss. Secondly, the carriers are also modified by the phase opposite disposition of the upper and lower carriers. The extra switching at the border of two adjacent regions in the space vector diagram is reduced. Meanwhile, a neutral-point voltage (NPV) control method is also presented. The duty cycle of the switching state that affects the NPV is adjusted to obtain the balance control of the NPV. Still, the switching sequence in each carrier period remains the same. Finally, the feasibility and effectiveness of the proposed DPWM strategy are tested on a rapid control prototype platform based on RT-Lab.

Space vector modulation with reduced common mode voltage for six-phase drives

2020 ◽  
Vol 39 (2) ◽  
pp. 395-411
Author(s):  
Mohammad Jafar Zandzadeh ◽  
Mohsen Saniei ◽  
Reza Kianinezhad
Keyword(s):  
Pulse Width ◽  
Pulse Width Modulation ◽  
Torque Ripple ◽  
Drive System ◽  
Limiting Factors ◽  
Space Vector ◽  
Common Mode ◽  
Content Type ◽  
Common Mode Voltage ◽  
Space Vectors

Purpose This paper aims to present a modified space vector pulse width modulation (SVPWM) technique for six-phase induction motor drive based on common-mode voltage (CMV) and current losses which are two important issues affecting drive system behavior and quality. Design/methodology/approach It is shown that the presence of z-component currents and the presence of CMV in six-phase drive system are two major limiting factors in space vector selection. The behavior of several space vector selections in a two-level inverter considering minimum CMV and z-components is investigated. Then, the space vectors in a three-level inverter is analyzed and tried to explore an SVM technique with better behavior. Findings The analyses show that all the problems cannot be solved in a six-phase drive system with two-level inverter despite having 64 space vectors; this study tried to overcome the limitations by exploring space vectors in a three-level inverter. Originality/value The proposed pulse width modulation (PWM) strategy leads to minimum current distortion and undesired current components with zero CMV and modest torque ripple.

scholarly journals Design and Simulation of a Single Phase Four Level Neutral Point Clamped Inverter

2019 ◽  
Vol 8 (2) ◽  
pp. 5285-5287
Keyword(s):  
Normal Mode ◽  
Pulse Width ◽  
Single Phase ◽  
Pulse Width Modulation ◽  
Reference Signal ◽  
Neutral Point ◽  
Half Cycle ◽  
Adjustment Strategy ◽  
Four Levels ◽  
Sinusoidal Pulse Width Modulation

In this paper, sinusoidal pulse width adjustment strategy for single stage four levels neutral point clamped inverter is proposed disposed of normal mode voltage. Sinusoidal pulse width modulation is much of the time utilized in modern applications. The gating sign are created by contrasting a sinusoidal reference signal and a triangular bearer sign of recurrence. The quantity of heartbeats per half-cycle relies upon the transporter recurrence

scholarly journals A Five-Level Converter in a Three-Level Mode for Common-Mode Leakage Current Suppression in PV-Generation Systems

2021 ◽  
Author(s):  
Aleksey Vyacheslavovich Udovichenko ◽  
Sergey Viktorovich Brovanov ◽  
Evgeny Valerievich Grishanov ◽  
Svetlana Mikhailovna Stennikova
Keyword(s):  
Leakage Current ◽  
Pulse Width ◽  
Pulse Width Modulation ◽  
Renewable Energy Sources ◽  
Multilevel Converter ◽  
Generation System ◽  
Common Mode ◽  
Common Mode Voltage ◽  
Conducting Research ◽  
Pv Generation

Power generation systems based on renewable energy sources are finding ever-widening applications and many researchers work on this problem. Many papers address the problem of transformerless structures, but few of them are aimed at conducting research on structures with multilevel converter topologies. In this paper a grid-tied transformerless PV-generation system based on a multilevel converter is discussed. There are common-mode leakage currents which act as a parasitic factor. It is also known that common-mode voltage is the main cause of the common-mode leakage current in grid-tied PV-generation systems. This paper considers the space vector pulse-width modulation (PWM) technique which is used to suppress or reduce common-mode leakage current. The proposed engineering solutions for a generation system based on the multilevel converter controlled with a pulse-width modulation technique are verified by experiment.

Sign in / Sign up

Export Citation Format

Share Document