High efficiency multilevel uninterruptible power supply

Author(s):  
E.K. Sato ◽  
M. Kinoshita ◽  
Y. Yamamoto ◽  
T. Amboh
2013 ◽  
Vol 16 (3) ◽  
pp. 29-40
Author(s):  
Phuong Minh Le ◽  
Dzung Quoc Phan ◽  
Huy Minh Nguyen ◽  
Phong Hoai Nguyen

This paper presents an implementation of the DC/DC push–pull converter for an uninterruptible power supply (UPS). Some classical DC/DC converters are presented and analyzed for pointing out their advantages and drawbacks. Besides, an original system based on a push-pull converter associated with a dynamic modulation control is chosen. The main advantage is the possibility to control the delivered electric power in a wide range from very low level to high level of voltage within the same basic architecture. It can reduce the switching power losses and increase the power conversion efficiency. This paper proposed a new control scheme of the DC/DC converter and DC/AC inverter. The suggested system consists of a high efficiency DC/DC converter and a singlephase DC/AC inverter has been simulated using Matlab/Simulink and designed basing on the DSP TMS320F28027. Both results show high performances of the DC link and AC load voltages, when load changes from zero to rated. The performance of the proposed system has been verified through a 1kW prototype of the system for a 50 Hz/220-230 VAC load sourcing by two series connected batteries of 12V. The proposed DC/DC converter achieves a high efficiency of 93.0%. The system including the DC/DC converter and DC/AC inverter achieves an efficiency of 91.2% and Total Harmonic Distortion (THD) of AC load voltage reached 1.9%.


2015 ◽  
Vol 764-765 ◽  
pp. 466-470
Author(s):  
Maoh Chin Jiang ◽  
Bing Jyun Shih

A single-stage DC uninterruptible power supply (UPS) is proposed in this paper. Basically, the proposed converter is an integration result of a power factor correction circuit with a dc-to-dc converter to achieve simple hardware circuit, high efficiency, and low cost for extra UPS function. Under normal operation, a novel two-switch SEPIC converter operates as an ac to dc converter with sinusoidal input current, unity power factor, and low ripple dc output voltage, and as a battery charger if a battery is added. Since both the input boost supply and the output supply can be controlled independently, a fast transient response can be maintained at both the input for active current wave shaping and at the output for good output regulation. When the ac source is in an outage condition, the proposed converter functions as a dc-to-dc buck-boost converter; therefore, the desired dc output voltage can be provided. Finally, some experimental results are presented for verification.


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