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A single-stage isolated ac–ac converter without the commutation problem is proposed. The proposed converter has the step-up/down function dependence on the phase shift control which provides zero-voltage switching zero-voltage switching (ZVS) for all switches in rated condition. Also, the commutation paths of the secondary side switches are provided for any switching case by adding a single capacitor; originally, a filter capacitor is used for the switching mode power supply input, and in this case, this filter capacitor also solves the primary-side commutation problem. The ZVS and solving the commutation problem increase the power efficiency and reliability. The proposed converter achieves high power quality with a simple control algorithm. A 1 kW/ 220 Vrms prototype is implemented to verify the theoretical analysis and performance of the proposed converter. The California energy commission efficiency is 97.3%, the total harmonic distortion (THD) of the input current is 2.45% at full load, and the THD of the output voltage is 1.07% at full load. [ABSTRACT FROM AUTHOR]

This study proposes a bidirectional grid-connected single-power-conversion converter with low-input battery voltage. The proposed bidirectional converter consists of a bidirectional dc–dc converter and an unfolding bridge, and the power conversion stage only corresponds to a bidirectional dc–dc converter. The bidirectional dc-dc converter can perform bidirectional power conversion between the low input battery voltage and a rectified sine wave due to its step-up/down voltage regulation functions. The unfolding bridge unfolds the rectified sine wave into the grid voltage and provides a current path to the grid. The study also proposes a control algorithm to regulate the grid current through a single power-processing stage. The control algorithm is comprised of a feed-forward nominal voltage compensator and a repetitive control scheme. The feed-forward nominal voltage compensator presets the operating point to lighten the burden of the grid current control, and the repetitive controller provides precise control of the grid current. Thus, the proposed bidirectional grid-connected single-power-conversion converter results in high power quality and high efficiency. Experimental results based on a 250-W prototype module are conducted to evaluate the performance of the converter and to verify the analysis. [ABSTRACT FROM AUTHOR]

This paper proposes a high-efficiency two-stage three-level grid-connected photovoltaic (PV) inverter. The proposed two-stage inverter comprises a three-level step-up converter and a three-level inverter. The three-level step-up converter not only improves the power-conversion efficiency by lowering the voltage stress but also guarantees the balancing of the dc-link capacitor voltages using a simple control algorithm; it also enables the proposed inverter to satisfy the VDE 0126-1-1 standard of leakage current. The three-level inverter minimizes the overall power losses with zero reverse-recovery loss. Furthermore, it reduces harmonic distortion, the voltage ratings of the semiconductor device, and the electromagnetic interference by using a three-level circuit configuration; it also enables the use of small and low-cost filters. To control the grid current effectively, we have used a feed-forward nominal voltage compensator with a mode selector; this compensator improves the control environment by presetting the operating point. The proposed high-efficiency two-stage three-level grid-connected PV inverter overcomes the low efficiency problem of conventional two-stage inverters, and it provides high-power quality with maximum efficiency of 97.4%. Using a 3-kW prototype of the inverter, we have evaluated the performance of the model and proved its feasibility. [ABSTRACT FROM PUBLISHER]

A high-efficiency bridgeless three-level power factor correction (PFC) rectifier is proposed. The circuit configuration of the proposed rectifier consists of four metal oxide semiconductor field-effect transistor (MOSFET) switches, and the reverse recovery problems of the switches are eliminated. Also, the proposed rectifier with three voltage levels reduces the power losses, harmonic components, voltage ratings, and electromagnetic interference. To control the grid current and the output voltage effectively, a feed-forward nominal voltage compensator with the mode selector is developed; by presetting the operating point of the grid voltage, this compensator improves the control environment. Thus, the proposed three-level PFC rectifier with developed control algorithm provides high power quality and high efficiency of 99.05%. Experimental results based on a 1-kW prototype are provided to evaluate its performance and verify the analysis. [ABSTRACT FROM AUTHOR]

This paper presents an asynchronous pipelined all-digital 10-b time-to-digital converter (TDC) with fine resolution, good linearity, and high throughput. Using a 1.5-b/stage pipeline architecture, an on-chip digital background calibration is implemented to correct residue subtraction error in the seven MSB stages. An asynchronous clocking scheme realizes pipeline operation for higher throughput. The TDC was implemented in standard 0.13-µm CMOS technology and has a maximum throughput of 300 MS/s and a resolution of 1.76 ps with a total conversion range of 1.8 ns. The measured DNL and INL were 0.6 LSB and 1.9 LSB, respectively. [ABSTRACT FROM AUTHOR]

This paper describes the first implementation of the well-known cyclic ADC architecture into a time-to-digital converter. With an asynchronous clocking scheme, an all-digital 1.5b time-domain multiplying DAC (MDAC) is repetitively used for 8b conversion. The MDAC is based on a 2\times time amplifier with an offset-compensated gain calibration scheme. The proposed cyclic TDC, fabricated in a 0.13 \mu\m CMOS, shows a resolution of 1.25 ps with a total conversion range of \pm160 ps, the maximum operating frequency of 100 MHz, and a power consumption of 4.3 mW at 50 MHz. The measured DNL and INL are \pm0.7 LSB and -3 to +1 LSB, respectively. [ABSTRACT FROM AUTHOR]