采用最大转换效率来衡量光伏并网逆变器的发电效率的评价方式存在一定的局限性。文章通过分析空间矢量脉宽调制(SVPWM)和不连续脉宽调制(DPWM)方式下光伏并网逆变器损耗分布情况,比较了两种调制方式以及开关频率对逆变器全功率范围内加...采用最大转换效率来衡量光伏并网逆变器的发电效率的评价方式存在一定的局限性。文章通过分析空间矢量脉宽调制(SVPWM)和不连续脉宽调制(DPWM)方式下光伏并网逆变器损耗分布情况,比较了两种调制方式以及开关频率对逆变器全功率范围内加权效率的影响,提出了一种在轻载工况下采用SVPWM、重载工况下采用DPWM、在低直流电压等级下提高功率器件开关频率的分段调制策略,并在500 k W光伏并网逆变器上进行了加权效率试验。试验结果验证了该分段调制策略的有效性。展开更多
This article presents a control strategy based on simple digital pulse-width modulation （DPWM） and pulse-skip modulation （PSM） for a DC-DC boost converter, to drive a luminance-regulated white light emitting diod...This article presents a control strategy based on simple digital pulse-width modulation （DPWM） and pulse-skip modulation （PSM） for a DC-DC boost converter, to drive a luminance-regulated white light emitting diodes （WLEDs）. The presented control strategy not only retains most of the advantages and flexibilities of traditional digital PWM, but also reduces complexity and cost. Based on analyzing the principle of the presented control strategy, the white light emitting diode （WLED） driver is designed and simulated using the 0.6 μm CMOS process. Simulation results of the boost converter show that the power efficiency is above 76% for a full load, with a peak efficiency of 88% when supply voltage varies from 2.7 V to 5.5 V. The control strategy overcomes low efficiency for PWM mode with light load.展开更多
Over the last decade,practical digital control of high-frequency switched-mode power converters has moved from proof-of-concept demonstrations to controller chips commercially available from multiple vendors,with appl...Over the last decade,practical digital control of high-frequency switched-mode power converters has moved from proof-of-concept demonstrations to controller chips commercially available from multiple vendors,with applica-tions to point-of-load and isolated DC/DC converters,microprocessor power supplies,power-factor-correction rectifiers,and others.This paper summarizes some of the advances in the area,including approaches to realizations of high-per-formance,high-frequency digital pulse-width modulated(DPWM) controllers,related analysis,modeling and design techniques,as well as performance gains enabled by digital control such as dynamic response and efficiency improve-ments.Examples of experimentally demonstrated results are presented,together with pointers to areas of current and future research and development.展开更多
Digital pulse width modulator is an integral part in digitally controlled Direct Current to Direct Current (DC-DC) converter utilized in modern portable devices. This paper presents a new Digital Pulse Width Modulator...Digital pulse width modulator is an integral part in digitally controlled Direct Current to Direct Current (DC-DC) converter utilized in modern portable devices. This paper presents a new Digital Pulse Width Modulator (DPWM) architecture for DC-DC converter using mealy finite state machine with gray code encoding scheme and one hot encoding method to derive the variable duty cycle Pulse Width Modulation (PWM) signal without varying the clock frequency. To verify the proposed DPWM technique, the architecture with control input of six, five and four bits are implemented and the maximum operating frequency along with power consumption results is obtained for different Field Programmable Gate Array (FPGA) devices. The post layout timing results are presented showing that architecture can work with maximum frequency of 326 MHz and derive PWM signal of 3.59 MHz. Experimental results show the implementation of the proposed architecture in low-cost FPGA (Spartan 3A) with on-board oscillator clock frequency of 12 MHz which is multiplied internally by two with Digital Clock Manager (DCM) and derive the PWM signal of 1.5 MHz with a time resolution of 1 ps.展开更多
文摘采用最大转换效率来衡量光伏并网逆变器的发电效率的评价方式存在一定的局限性。文章通过分析空间矢量脉宽调制(SVPWM)和不连续脉宽调制(DPWM)方式下光伏并网逆变器损耗分布情况,比较了两种调制方式以及开关频率对逆变器全功率范围内加权效率的影响,提出了一种在轻载工况下采用SVPWM、重载工况下采用DPWM、在低直流电压等级下提高功率器件开关频率的分段调制策略,并在500 k W光伏并网逆变器上进行了加权效率试验。试验结果验证了该分段调制策略的有效性。
基金supported by the National Natural Science Foundation of China(60576043)
文摘This article presents a control strategy based on simple digital pulse-width modulation （DPWM） and pulse-skip modulation （PSM） for a DC-DC boost converter, to drive a luminance-regulated white light emitting diodes （WLEDs）. The presented control strategy not only retains most of the advantages and flexibilities of traditional digital PWM, but also reduces complexity and cost. Based on analyzing the principle of the presented control strategy, the white light emitting diode （WLED） driver is designed and simulated using the 0.6 μm CMOS process. Simulation results of the boost converter show that the power efficiency is above 76% for a full load, with a peak efficiency of 88% when supply voltage varies from 2.7 V to 5.5 V. The control strategy overcomes low efficiency for PWM mode with light load.
基金The work presented in this paper has been supported by industrial sponsors of the Colorado Power Electronics Center(CoPEC).The authors would like to acknowledge CoPEC graduate students for significant contributions to the results reported in this paper.
文摘Over the last decade,practical digital control of high-frequency switched-mode power converters has moved from proof-of-concept demonstrations to controller chips commercially available from multiple vendors,with applica-tions to point-of-load and isolated DC/DC converters,microprocessor power supplies,power-factor-correction rectifiers,and others.This paper summarizes some of the advances in the area,including approaches to realizations of high-per-formance,high-frequency digital pulse-width modulated(DPWM) controllers,related analysis,modeling and design techniques,as well as performance gains enabled by digital control such as dynamic response and efficiency improve-ments.Examples of experimentally demonstrated results are presented,together with pointers to areas of current and future research and development.
文摘Digital pulse width modulator is an integral part in digitally controlled Direct Current to Direct Current (DC-DC) converter utilized in modern portable devices. This paper presents a new Digital Pulse Width Modulator (DPWM) architecture for DC-DC converter using mealy finite state machine with gray code encoding scheme and one hot encoding method to derive the variable duty cycle Pulse Width Modulation (PWM) signal without varying the clock frequency. To verify the proposed DPWM technique, the architecture with control input of six, five and four bits are implemented and the maximum operating frequency along with power consumption results is obtained for different Field Programmable Gate Array (FPGA) devices. The post layout timing results are presented showing that architecture can work with maximum frequency of 326 MHz and derive PWM signal of 3.59 MHz. Experimental results show the implementation of the proposed architecture in low-cost FPGA (Spartan 3A) with on-board oscillator clock frequency of 12 MHz which is multiplied internally by two with Digital Clock Manager (DCM) and derive the PWM signal of 1.5 MHz with a time resolution of 1 ps.
