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![shows a detailed circuit diagram of the UPS reported in [6]. The circuit consist basically of, a ZCS partial series resonant DC-DC converter, a dynamic power compensator given by a bi-directional converter, and a voltage source fullbridge inverter. Advantages of the circuit are: power factor correction, soft commutation of the ZCS-PSRC converter and inverter switches that operates with 50Hz commutation frequency.](profile/Demercil-Oliveira/publication/4235524/figure/fig4/AS:394672842264577@1471108746042/shows-a-detailed-circuit-diagram-of-the-UPS-reported-in-6-The-circuit-consist.png)
shows a detailed circuit diagram of the UPS reported in [6]. The circuit consist basically of, a ZCS partial series resonant DC-DC converter, a dynamic power compensator given by a bi-directional converter, and a voltage source fullbridge inverter. Advantages of the circuit are: power factor correction, soft commutation of the ZCS-PSRC converter and inverter switches that operates with 50Hz commutation frequency.
Source publication
![Fig. 1. UPS system proposed in [1, 2].](profile/Demercil-Oliveira/publication/4235524/figure/fig1/AS:394672838070280@1471108745970/UPS-system-proposed-in-1-2_Q320.jpg)
![Fig. 2. UPS system proposed in [3]. This work was supported by...](profile/Demercil-Oliveira/publication/4235524/figure/fig2/AS:394672838070281@1471108745994/UPS-system-proposed-in-3-This-work-was-supported-by-Brazilian-Research-and-Projects_Q320.jpg)
![Fig. 3. UPS system proposed in [4].](profile/Demercil-Oliveira/publication/4235524/figure/fig3/AS:394672842264576@1471108746018/UPS-system-proposed-in-4_Q320.jpg)
![Fig. 5 shows a detailed circuit diagram of the UPS reported in [6]. The...](profile/Demercil-Oliveira/publication/4235524/figure/fig4/AS:394672842264577@1471108746042/shows-a-detailed-circuit-diagram-of-the-UPS-reported-in-6-The-circuit-consist_Q320.jpg)
![Fig.5. UPS system proposed in [6].](profile/Demercil-Oliveira/publication/4235524/figure/fig5/AS:394672842264578@1471108746072/UPS-system-proposed-in-6_Q320.jpg)
This paper proposes a double conversion UPS system with power factor correction, high frequency transformer isolation and 110V/220V input voltage characteristics. It's suitable for rack type structure because it has small size and reduced weight. For both input voltages, the proposed converter has almost the same efficiency processing the same outp...
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Citations
... A common configuration used in most part of applications is composed by two stages. The input stage is a high power factor preregulator followed by a second stage as a DC-DC converter, used in telecommunication infrastructure application or a DC-AC converter used in AC machine drive or uninterruptible power supply (UPS) applications [1]- [3]. ...
... However, the Manuscript galvanic isolation obtained with low frequency transformer increase the weight, volume and cost [1]. Therefore, the development of topologies including the galvanic isolation in high frequency link can increase significantly the UPS power density [1], [3], [4]. ...
The bridgeless boost-full-bridge rectifier is used as preregulator for a high frequency isolated UPS and the asymmetric pulse width modulation (APWM) modulation is applied in order to obtain a high quality input current with high power factor. The rectifier operates with soft-switching and reduced conduction losses improving the efficiency. A simultaneous phase-shift modulation allows obtain a fast output voltage control and step-up/step-down static gain, becoming possible the operation in a wide voltage range. An auxiliary power feed-forward action allows improving the dynamic response of the output voltage and primary side DC-bus voltage for the load transient. The double modulation and the auxiliary control action reduce the DC-bus voltage overshoot and undershoot during the output load transients, reduce the converter filters capacitance and limit the maximum voltage across the switches. The theoretical analysis and design procedure are presented for the modulations proposed and the experimental results were obtained from a 2 kW prototype operating with switching frequency equal to 44 kHz. The experimental results are presented using four different combinations of control structures showing comparatively the dynamic improvements.
... Now the transformer can be used at high frequency with the advantages of reduced volume, inherent property of galvanic isolation, and improved efficiency of the system. Several UPS topologies with high frequency transformer have been introduced in2021222324252627. Such UPS system has smaller size and weight as compare to the conventional UPS systems. ...
... A UPS with 110-V/220-V Input Voltage and High-frequency Transformer IsolationFig. 7 shows a flexible UPS topology which can operate over a wide range of input voltage [20] . During normal mode of operation , the chopper converts the grid voltage into DC and delivers high frequency pulses to the primary of the high frequency transformer. ...
Uninterruptible Power Supplies (UPS) have reached a mature level by providing clean and uninterruptible power to the sensitive loads in all grid conditions. Generally UPS system provides regulated sinusoidal output voltage, with low total harmonics distortion (THD), and high input power factor irrespective of the changes in the grid voltage. This paper provides comprehensive review of UPS topologies, circuit configurations, and different control techniques used in the UPS system. A comparison based on the performance, size, cost, and efficiency of the system is presented. Different hybrid energy source UPS system and new generation UPS system for smart grid and micro-grid has been explained. Finally the paper describes performance evaluation of UPS system and explains different aspects that are to be considered for choosing a suitable UPS system by the user.
... Many PFC converter applications require galvanic isolation between the mains and the load. These applications normally employ two-stage converters, where a boost PFC pre-regulator converter is cascaded to a dc-dc isolated converter [4] [6]. Although two-stage PFC circuits offer excellent performance in terms of input power factor, holdup time capability and low-frequency ripple in the output voltage, they have the disadvantages of low-power density. ...
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... Other topologies were proposed as a solution to overcome this problem by using a transformer in a high-frequency dc link [3]- [6]. Although UPS topology, incorporating a highfrequency transformer reduces the weight of the system, it has increased the number of active switches, compromising the system's overall efficiency and reliability. ...
A circuit configuration of a single-phase nonisolated online uninterruptible power supply (UPS) with 110-V/220-V input–output voltage ratings is proposed, allowing the bypass operation without a transformer even if the input voltage is different from the output voltage. The converter consists of an ac–dc/dc–dc three-level boost converter combined with a double half-bridge inverter. In this type of configuration size, cost and efficiency are improved due to the reduced number of switches and batteries, and also, no low-frequency isolation transformer is required to realize bypass operation because of the common neutral connection. Both stages of the proposed circuit operate at high frequency by using a passive nondissipative snubber circuit in the boost converter and insulated-gate bipolar-transistor switches in the double half-bridge inverter, with low conduction losses, low tail current, and low switching losses. Principle of operation and experimental results for a 2.6-kVA prototype are presented to demonstrate the UPS performance.
In this paper, the transformerless uninterruptible power supply (UPS) is explained. The use of the DC–DC bidirectional converter eliminates the transformer from the UPS structure. This not only reduces the size, weight, and cost of the system, but also prevents leakage currents due to the saturation of the transformer when the UPS operation is changed. Furthermore, by employing the quasi-half-bridge (QHB) structure in the UPS configuration, in addition to profiting from the advantages of unipolar modulation, the system efficiency is improved due to the switching of auxiliary leg switches in grid frequency. Subsequently, using the multiple-resonant controller in combination with a sinusoidal pulse width modulator leads to less total harmonic distortion in both input current and output voltage, compared to the allowed limit specified by the IEC62040 standard. To evaluate the robustness of the system toward grid voltage and load changes, first, the input voltage was varied by 40%, and then the nonlinear and step loads were applied to the system. Under these conditions, the QHB UPS demonstrated good behavior. This system was implemented experimentally in addition to simulations, and the results are presented.
This paper analyses and compares experimentally the magnetic hysteresis losses evolution in iron steel sheets submitted to different supplies: sinusoidal, square, triangular, two and three-level PWM voltage waveforms. The magnetic induction amplitude influence and the modulation index are investigated for Two and Three-level PWM voltage waveforms. The experimental investigation is performed using a workbench with a closed loop PWM inverter for imposing the induced voltage waveform on the secondary winding of an Epstein frame.
