A PWM Strategies for Diode Assisted NPC-MLI to Obtain Maximum Voltage Gain for EV Application

2017 ◽  
Vol 8 (2) ◽  
pp. 767 ◽  
Author(s):  
C. Bharatiraja ◽  
Shri Harish ◽  
J L Munda ◽  
P. Sanjeevikumar ◽  
M. Sriram Kumar ◽  
...  
Keyword(s):  
Pulse Width Modulation ◽  
Photovoltaic System ◽  
Duty Ratio ◽  
Voltage Gain ◽  
High Voltage Gain ◽  
Wide Range ◽  
Selection Approach ◽  
Power Switches ◽  
In Series ◽  
Maximum Voltage

The projected diode assisted Neutral Point Diode Clamed (NPC-MLI) with the photovoltaic system produces a maximum voltage gain that is comparatively higher than those of other boost conversion techniques. This paper mainly explores vector selection approach pulse-width modulation (PWM) strategies for diode-assisted NPC-MLI to obtain a maximum voltage gain without compromising in waveform quality. To obtain a high voltage gain maximum utilization of dc-link voltage and stress on the power switches must be reduced. From the above issues in the diode assisted NPC-MLI leads to vector selection approach PWM technique to perform capacitive charging in parallel and discharging in series to obtain maximum voltage gain. The operation principle and the relationship of voltage gain versus voltage boost duty ratio and switching device voltage stress versus voltage gain are theoretically investigated in detail. Owing to better performance, diode-assisted NPC-MLI is more promising and competitive topology for wide range dc/ac power conversion in a renewable energy application. Furthermore, theoretically investigated are validated via simulation and experimental results.

Development of Serial-Connected High Step-Up DC-DC Converter with Single Switch

2013 ◽  
Vol 479-480 ◽  
pp. 535-539
Author(s):  
Van Tsai Liu ◽  
Chien Hao Hsu
Keyword(s):  
Electric Vehicles ◽  
Pulse Width Modulation ◽  
Hybrid Electric Vehicles ◽  
Single Pulse ◽  
Input Voltage ◽  
Duty Ratio ◽  
Leakage Inductance ◽  
High Voltage Gain ◽  
Output Capacitor ◽  
Voltage Spike

In this paper, a novel high step-up DC-DC converter has been designed for fuel cell applications. The proposed high step-up converter can be used for various portable energy storage components such as fuel cells which are used for hybrid electric vehicles (HEV), and light electric vehicles (LEV).The proposed converter is integrated by boost circuit, voltage lift capacitor, and coupled-inductor techniques to achieve high step-up voltage and has several advantages. First, the circuit is controlled by one single pulse width modulation (PWM). Second, the converter consists of active clamp circuit to recycle the leakage inductance and send to output capacitor so that the voltage spike on active switch is suppressed and efficiency is also improved. Third, by using the winding of secondary boost circuit, and voltage lift capacitor techniques, the high voltage gain can be achieved without more than 50% duty ratio, and the slope compensation circuit can also be simplified.Finally, a 1k W prototype converter is implemented, to verify the performance of the proposed converter with input voltage 48V, output voltage 400V, and output power 1k W is also achieved. The highest efficiency is 92.96% at 400W, and the full-load efficiency is up to 90.48%.

scholarly journals High Step-up Coupled Inductor Inverters Based on qSBIs

Energies ◽  
2019 ◽  
Vol 12 (15) ◽  
pp. 3032 ◽  
Author(s):  
Hongchen Liu ◽  
Xi Su ◽  
Junxiong Wang
Keyword(s):  
Steady State ◽  
High Voltage ◽  
Low Voltage ◽  
Duty Ratio ◽  
Voltage Gain ◽  
Passive Components ◽  
Steady State Analysis ◽  
High Voltage Gain ◽  
Voltage Stress ◽  
Working Principle

In this paper, two types of high step-up coupled inductor inverters based on qSBIs (quasi- switched boost inverters) are proposed. By applying the coupled inductor to the qSBIs, the voltage gain of the proposed inverter is regulated by turn ratio and duty ratio. Thus, a high voltage gain can be achieved without the circuits operating at the extreme duty cycle by choosing a suitable turn ratio of the coupled inductor. In addition, the proposed circuits have the characteristics of continuous input current and low voltage stress across the passive components. A boost unit can be added to the proposed inverters for further improvement of the voltage gain. In this paper, the working principle, steady state analysis, and the comparisons of the proposed inverter with other impedance-source inverters are described. A 200 W prototype was created and the experimental results confirm the correctness of the analysis in this paper.

scholarly journals A dual-switch cubic SEPIC converter with extra high voltage gain

2021 ◽  
Vol 12 (1) ◽  
pp. 199
Author(s):  
Christophe Raoul Fotso Mbobda ◽  
Alain Moise Dikandé
Keyword(s):  
High Voltage ◽  
Duty Cycle ◽  
Magnetic Coupling ◽  
Conversion Ratio ◽  
Duty Ratio ◽  
Voltage Gain ◽  
High Voltage Gain ◽  
Voltage Stress ◽  
Extra High Voltage ◽  
Voltage Conversion

To provide a high votage conversion ratio, conventional non-isolated DC-DC boost topologies, which have reduced voltage boost capability, have to operate with extremely high duty cycle ratio, higher than 0.9. This paper proposes a DC-DC converter which is mainly based on the narrow range of duty cycle ratio to achieve extra high voltage conversion gain at relatively reduced voltage stress on semiconductors. In addition, it does include any magnetic coupling structure. The structure of the proposed converter combines the new hybrid SEPIC converter and voltage multiplier cells. From the steady-state analysis, this converter has wide conversion ratio and cubic dependence with respect to the duty ratio and then, can increase the output voltage several times more than the conventional and quadratic converters at the same duty cycle ratio. However, the proposed dual-switch cubic SEPIC converter must withstand higher voltage stress on output switches. To overcome this drawback, an extension of the proposed converter is also introduced and discussed. The superiority of the proposed converter is mainly based on its cubic dependence on the duty cycle ratio that allows it to achieve extra high voltage gain at reduced voltage stress on semiconductors. Simulation results are shown and they corroborate the feasibility, practicality and validity of the concepts of the proposed converter.

Single-Phase Single Stage String Inverter for Grid Connected Photovoltaic System

2015 ◽  
Vol 785 ◽  
pp. 177-181
Author(s):  
Siti Zaliha Mohammad Noor ◽  
Ahmad Maliki Omar ◽  
M.A.M. Radzi
Keyword(s):  
Simulation Model ◽  
Single Phase ◽  
Pulse Width Modulation ◽  
Single Stage ◽  
Maximum Power ◽  
Photovoltaic System ◽  
Prototype System ◽  
Point Tracking ◽  
Power Switches ◽  
Power Point

This paper presents the development of single-phase single stage string inverters for grid connected photovoltaic system. The inverter is designed to generate an AC current in phase with the grid voltage and to extract the maximum power from the PV array. The maximum power point tracking (MPPT) is achieved by adjusting the modulation index and phase angle of the inverter’s voltage accordingly using fuzzy logic control algorithm. The prototype system is tested using 2 series of STP170s-24/Ac PV modules. Insulated Gate Bipolar Transistors (IGBTs) are used as power switches while the Sinusoidal Pulse Width Modulation (SPWM) scheme is used as the switching technique to synthesize the output waveform. Simulation model was developed in MATLAB/Simulink environment to study and evaluate behavior of the proposed converter. The results of the prototype system show good agreement with the simulation model.

scholarly journals High Gain and Reduced Switch Stress DC-DC Converter Topology for PV System

2018 ◽  
Vol 7 (04) ◽  
pp. 23808-23816
Author(s):  
C. Srideepa ◽  
S.Sathish Kumar ◽  
R. Nagarajan
Keyword(s):  
High Gain ◽  
Photovoltaic System ◽  
Voltage Gain ◽  
Pv System ◽  
Power Switch ◽  
High Voltage Gain ◽  
Voltage Stress ◽  
Converter Topology ◽  
State Resistance ◽  
Two Hybrid

This paper presents a new high step-up isolated DC-DC converter topology for photovoltaic system. The suggested configuration provides a converter with high voltage gain and reduced switch stress by using three coupled inductor with two hybrid voltage multiplier cell. The operation of the proposed converter is based on a charging capacitor with a single switch in its structure. A passive clamp circuit composed of capacitors and diodes is employed in the converter structure for lowering the voltage stress on the power switch as well as increasing the voltage gain of the converter. Since the voltage stress is low in the provided topology, a switch with a small ON-state resistance can be used. As a result, the losses are decreased and the efficiency is increased. The design of DC-DC boost converter is also discussed in detail. Simulation of DC-DC converter is performed in MATLAB/Simulink and the result are verified

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