Analysis of Capacitor Voltage Imbalance in Hybrid Converters and Inherently Balanced Operation Using Symmetric Architecture

<p>This paper investigates the origin of the flying capacitor voltage imbalance in hybrid converters. By observation and logical deduction, an intuitive voltage-charge relationship is established which can give a general explanation of the flying capacitor voltage balance in hybrid converters. This relationship can establish a relatively simple and intuitive method to identify the difference of balance performance in hybrid converters for Vout<(V_in /N) cases. Converter with even number of inductor charging intervals, are shown to be susceptible to flying capacitor voltage imbalance, while flying capacitors in hybrid converters with inductors having odd charging intervals have inherently balanced operations. As a direct result of the analysis, a new symmetric operation of FCML converters is introduced to achieve an inherent balance of flying capacitor voltages. Hardware implementations and experiments have been carried out for verifications of the analytical analysis and the new symmetric operation.</p>

A Two-Stage 110VAC-to-1VDC Power Delivery Architecture Using Hybrid Converters for Data Centers and Telecommunication Systems

<p>Improving power delivery and management plays a key role in minimizing the cost of building and operating future green data centers to meet the fast growth of high-performance computing. Toward this important goal, this paper presents a new complete power delivery architecture to bridge AC grid voltages to core levels for computing loads using only 2 conversion stages with new converter topologies. The first stage converts a commercial AC line voltage of 90V-110V to a 48-60V intermediate bus with power factor correction (PFC). The second stage converts the bus voltage to core voltages of ~1 V with high current density and simple duty cycle control. Individually, the first stage was measured at 96.1% peak efficiency for output currents ranging in 0-4.5 A, while the second stage achieved 90.7% peak efficiency with a load range of 0-220 A at 1 V. Measured peak power densities are 73 W/in3 for the first stage and 2020 W/in3 for the second stage. In combination, the direct conversion from a line AC voltage of ~110 VAC to 1 VDC achieves a peak efficiency of 84.1% while providing output currents up to 160A.</p>

Analysis of Capacitor Voltage Imbalance in Hybrid Converters and Inherently Balanced Operation Using Symmetric Architecture

<p>This paper investigates the origin of the flying capacitor voltage imbalance in hybrid converters. By observation and logical deduction, an intuitive voltage-charge relationship is established which can give a general explanation of the flying capacitor voltage balance in hybrid converters. This relationship can establish a relatively simple and intuitive method to identify the difference of balance performance in hybrid converters for Vout<(V_in /N) cases. Converter with even number of inductor charging intervals, are shown to be susceptible to flying capacitor voltage imbalance, while flying capacitors in hybrid converters with inductors having odd charging intervals have inherently balanced operations. As a direct result of the analysis, a new symmetric operation of FCML converters is introduced to achieve an inherent balance of flying capacitor voltages. Hardware implementations and experiments have been carried out for verifications of the analytical analysis and the new symmetric operation.</p>

A Two-Stage 110VAC-to-1VDC Power Delivery Architecture Using Hybrid Converters for Data Centers and Telecommunication Systems

<p>Improving power delivery and management plays a key role in minimizing the cost of building and operating future green data centers to meet the fast growth of high-performance computing. Toward this important goal, this paper presents a new complete power delivery architecture to bridge AC grid voltages to core levels for computing loads using only 2 conversion stages with new converter topologies. The first stage converts a commercial AC line voltage of 90V-110V to a 48-60V intermediate bus with power factor correction (PFC). The second stage converts the bus voltage to core voltages of ~1 V with high current density and simple duty cycle control. Individually, the first stage was measured at 96.1% peak efficiency for output currents ranging in 0-4.5 A, while the second stage achieved 90.7% peak efficiency with a load range of 0-220 A at 1 V. Measured peak power densities are 73 W/in3 for the first stage and 2020 W/in3 for the second stage. In combination, the direct conversion from a line AC voltage of ~110 VAC to 1 VDC achieves a peak efficiency of 84.1% while providing output currents up to 160A.</p>

Wielopoziomowe przekształtniki energoelektroniczne – topologie, zasada działania, metody modulacji

In this paper selected issues concerning topological structure, operation and control as well as modulation methods used in multilevel converters are presented. There is reviewed general topologies of multilevel converters, which include Diode-Clamped Converters, Capacitor-Clamped Converters, Cascade Converters and Hybrid Converters. The general structure of a multilevel converter consisting of several stages depending on its application and topology is described. In the structure of operation, the stages of Outer Control Loop, Inner Control Loop, DC voltage stabilization and modulation are specified. Next, the division of modulation methods used in multilevel converters is presented and a detailed description of selected modulation methods is made. In the further part of the article the modulation methods were described in detail, i.e. the Level-Shifted Carrier Modulation Technique and Phase-Shifted Carrier Modulation Technique were used to present the analysis of power losses in multilevel converters.