Full bridge Zero Voltage Switch PWM converter combines advantages of the PWM control technique and resonant technique. However, Full ZVS is achieved only under large load current because resonant tank of this circu...Full bridge Zero Voltage Switch PWM converter combines advantages of the PWM control technique and resonant technique. However, Full ZVS is achieved only under large load current because resonant tank of this circuit is made up of the parasitic capacitance of the power semiconductors and the leakage inductor of the transformer primary. In this paper two saturable inductors as magnetic switches are added to secondary, so output inductor is always reflected to primary and assists resonant transition. Full ZVS is achieved under lower load current. The above mentioned investigated results are validated by the computerized simulation and hardware circuit experiment.展开更多
In this review article, a stage-convertible RF power amplifier designed with a 0.18-μm RF CMOS process is described. A method to implement a low-power matching network is an essential technology for the stage-convert...In this review article, a stage-convertible RF power amplifier designed with a 0.18-μm RF CMOS process is described. A method to implement a low-power matching network is an essential technology for the stage-convertible power amplifier. Various low-power matching networks with distributed active transformers as an output power combiner are compared in terms of the amounts of undesired coupling, the chip size, and the amount of power loss. The feasibility of a differential line inductor for the stage-convertible power amplifier is assessed and explained. Finally, we show that the differential line inductor is a realistic means of reducing the overall chip size, enhancing the quality factor of the matching network, and minimizing the undesired coupling between the inter-stage matching network and any output matching network. Additionally, the operating mechanism of the stage-convertible power amplifier using the differential line inductor for a low-power matching network is described in detail.展开更多
SS型Buck-WPT(Buck-wireless power transfer)系统由Buck电路和基本的SS型无线电能传输电路组成。该电路系统因为结构和控制方式简单、控制效果明显等优点在感应式无线电能传输方面得到广泛应用。但该电路的动态特性并不能满足一些时变...SS型Buck-WPT(Buck-wireless power transfer)系统由Buck电路和基本的SS型无线电能传输电路组成。该电路系统因为结构和控制方式简单、控制效果明显等优点在感应式无线电能传输方面得到广泛应用。但该电路的动态特性并不能满足一些时变系统对快速性的较高要求。例如,系统在启动时会存在较强震荡和较大超调,系统负载改变时稳定状态会发生改变且存在明显抖动,系统极限空载时原边谐振电流会增大,且该电流值远超出安全工作范围。本文提出了一种基于可控电感的SS型Buck-WPT系统。首先,分析了电感值可调的方法并在COMSOL中建立仿真模型验证其电感值可控的特性。其次,对SS型Buck-WPT系统进行数学建模,将SS型WPT系统作为Buck电路的特殊负载,推导SS型Buck-WPT系统状态空间方程。研究其三维空间内相轨迹的降维描述方法,将该系统用二维相轨迹描述系统运行过程。然后,通过分析启动阶段相轨迹运行规律,改进前级Buck电路。将传统Buck电路中的电感换成可控电感,运用其电感值可调的控制系统开通阶段的运行轨迹,使系统在1个开关周期内无超调快速进入稳态。当系统负载改变时,系统的输出电压会改变,且是不断抖动来回反复的过程,利用PI算法对系统进行恒流控制。通过可控电感控制系统相轨迹,使副边输出能无抖动快速进入稳态,保证输出电压不变。针对SS型谐振网络的Buck-WPT系统中出现空载大电流的问题,提出了将可控电感串联接入原边谐振网络的方法。实时检测原边谐振电流值,该值超过正常工作范围,感值就快速增大,减小原边谐振电流,达到空载时维持原边谐振电流安全值以下。最后,验证上述方法在优化SS型Buck-WPT系统动态特性的有效性,在Simulink中搭建仿真电路。该方法能减小工作条件改变时带来的系统抖动,且在不改变系统响应速度前提下减小超调,优化系统动态性能,增强系统抗负载扰动力,提高系统带负载能力有明显效果。展开更多
The use of reluctance networks has been a conventional practice to analyze transformer structures. Basic transformer structures can be well analyzed by using the magnetic-electric analogues discovered by Heaviside in ...The use of reluctance networks has been a conventional practice to analyze transformer structures. Basic transformer structures can be well analyzed by using the magnetic-electric analogues discovered by Heaviside in the 19th century. However, as power transformer structures are getting more complex today, it has been recognized that changing transformer structures cannot be accurately analyzed using the current reluctance network methods. This paper presents a novel method in which the magnetic reluctance network or arbitrary complexity and the surrounding electrical networks can be analyzed as a single network. The method presented provides a straightforward mapping table for systematically linking the electric lumped elements to magnetic circuit elements. The methodology is validated by analyzing several practical transformer structures. The proposed method allows the analysis of coupled inductor of any complexity, linear or non-linear.展开更多
This paper deals with a parallel processing uninterruptible power supply (UPS) for sudden voltage fluctuation in power management to integrate power quality improvement, load voltage stabilization and UPS. To reduce t...This paper deals with a parallel processing uninterruptible power supply (UPS) for sudden voltage fluctuation in power management to integrate power quality improvement, load voltage stabilization and UPS. To reduce the complexity, cost and number of power conversions, which results in higher efficiency, only one voltage-controlled voltage source inverter (VCVSI) is used. The VCVSI is connected in series on the DC battery side and in parallel on the AC grid side with a decoupling inductor. The system provides sinusoidal voltage at the fundamental value of 220V/60Hz for the load during abnormal utility power conditions or grid failure. Also, the system can be operated to mitigate the harmonic current and voltage demand from nonlinear loads and provide voltage stabilization for loads when sudden voltage fluctuation occur, such as sag and swell. The experimental results confirm the system protects against outages caused by abnormal utility power conditions and sudden voltage fluctuations and change.展开更多
High temperature superconducting （HTS） power inductor and its control technology have been studied and analyzed in the paper. Based on the results of simulations and practical experiments, a controlled release schem...High temperature superconducting （HTS） power inductor and its control technology have been studied and analyzed in the paper. Based on the results of simulations and practical experiments, a controlled release scheme has been proposed and verified for developing a practical HTS SMES prototype.展开更多
文摘Full bridge Zero Voltage Switch PWM converter combines advantages of the PWM control technique and resonant technique. However, Full ZVS is achieved only under large load current because resonant tank of this circuit is made up of the parasitic capacitance of the power semiconductors and the leakage inductor of the transformer primary. In this paper two saturable inductors as magnetic switches are added to secondary, so output inductor is always reflected to primary and assists resonant transition. Full ZVS is achieved under lower load current. The above mentioned investigated results are validated by the computerized simulation and hardware circuit experiment.
文摘In this review article, a stage-convertible RF power amplifier designed with a 0.18-μm RF CMOS process is described. A method to implement a low-power matching network is an essential technology for the stage-convertible power amplifier. Various low-power matching networks with distributed active transformers as an output power combiner are compared in terms of the amounts of undesired coupling, the chip size, and the amount of power loss. The feasibility of a differential line inductor for the stage-convertible power amplifier is assessed and explained. Finally, we show that the differential line inductor is a realistic means of reducing the overall chip size, enhancing the quality factor of the matching network, and minimizing the undesired coupling between the inter-stage matching network and any output matching network. Additionally, the operating mechanism of the stage-convertible power amplifier using the differential line inductor for a low-power matching network is described in detail.
文摘SS型Buck-WPT(Buck-wireless power transfer)系统由Buck电路和基本的SS型无线电能传输电路组成。该电路系统因为结构和控制方式简单、控制效果明显等优点在感应式无线电能传输方面得到广泛应用。但该电路的动态特性并不能满足一些时变系统对快速性的较高要求。例如,系统在启动时会存在较强震荡和较大超调,系统负载改变时稳定状态会发生改变且存在明显抖动,系统极限空载时原边谐振电流会增大,且该电流值远超出安全工作范围。本文提出了一种基于可控电感的SS型Buck-WPT系统。首先,分析了电感值可调的方法并在COMSOL中建立仿真模型验证其电感值可控的特性。其次,对SS型Buck-WPT系统进行数学建模,将SS型WPT系统作为Buck电路的特殊负载,推导SS型Buck-WPT系统状态空间方程。研究其三维空间内相轨迹的降维描述方法,将该系统用二维相轨迹描述系统运行过程。然后,通过分析启动阶段相轨迹运行规律,改进前级Buck电路。将传统Buck电路中的电感换成可控电感,运用其电感值可调的控制系统开通阶段的运行轨迹,使系统在1个开关周期内无超调快速进入稳态。当系统负载改变时,系统的输出电压会改变,且是不断抖动来回反复的过程,利用PI算法对系统进行恒流控制。通过可控电感控制系统相轨迹,使副边输出能无抖动快速进入稳态,保证输出电压不变。针对SS型谐振网络的Buck-WPT系统中出现空载大电流的问题,提出了将可控电感串联接入原边谐振网络的方法。实时检测原边谐振电流值,该值超过正常工作范围,感值就快速增大,减小原边谐振电流,达到空载时维持原边谐振电流安全值以下。最后,验证上述方法在优化SS型Buck-WPT系统动态特性的有效性,在Simulink中搭建仿真电路。该方法能减小工作条件改变时带来的系统抖动,且在不改变系统响应速度前提下减小超调,优化系统动态性能,增强系统抗负载扰动力,提高系统带负载能力有明显效果。
文摘The use of reluctance networks has been a conventional practice to analyze transformer structures. Basic transformer structures can be well analyzed by using the magnetic-electric analogues discovered by Heaviside in the 19th century. However, as power transformer structures are getting more complex today, it has been recognized that changing transformer structures cannot be accurately analyzed using the current reluctance network methods. This paper presents a novel method in which the magnetic reluctance network or arbitrary complexity and the surrounding electrical networks can be analyzed as a single network. The method presented provides a straightforward mapping table for systematically linking the electric lumped elements to magnetic circuit elements. The methodology is validated by analyzing several practical transformer structures. The proposed method allows the analysis of coupled inductor of any complexity, linear or non-linear.
文摘This paper deals with a parallel processing uninterruptible power supply (UPS) for sudden voltage fluctuation in power management to integrate power quality improvement, load voltage stabilization and UPS. To reduce the complexity, cost and number of power conversions, which results in higher efficiency, only one voltage-controlled voltage source inverter (VCVSI) is used. The VCVSI is connected in series on the DC battery side and in parallel on the AC grid side with a decoupling inductor. The system provides sinusoidal voltage at the fundamental value of 220V/60Hz for the load during abnormal utility power conditions or grid failure. Also, the system can be operated to mitigate the harmonic current and voltage demand from nonlinear loads and provide voltage stabilization for loads when sudden voltage fluctuation occur, such as sag and swell. The experimental results confirm the system protects against outages caused by abnormal utility power conditions and sudden voltage fluctuations and change.
文摘High temperature superconducting （HTS） power inductor and its control technology have been studied and analyzed in the paper. Based on the results of simulations and practical experiments, a controlled release scheme has been proposed and verified for developing a practical HTS SMES prototype.
