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The second edition of the book extends the scope of the first edition to the emerging topic of Dc Power Distribution Systems . Starting from the converter circuit analyses, small‐signal modeling and dynamic analyses, and control designs for standalone dc‐to‐dc converters, the book culminates with Four New Chapters about Dc Power Distribution Systems , covering the system stability, subsystem compatibility, line filter considerations, and system design/integration for predictable/programmable performance.

The second edition of the book extends the scope of the first edition to the emerging topic of Dc Power Distribution Systems . Starting from the converter circuit analyses, small‐signal modeling and dynamic analyses, and control designs for standalone dc‐to‐dc converters, the book culminates with Four New Chapters about Dc Power Distribution Systems , covering the system stability, subsystem compatibility, line filter considerations, and system design/integration for predictable/programmable performance.

The second edition of the book extends the scope of the first edition to the emerging topic of Dc Power Distribution Systems . Starting from the converter circuit analyses, small‐signal modeling and dynamic analyses, and control designs for standalone dc‐to‐dc converters, the book culminates with Four New Chapters about Dc Power Distribution Systems , covering the system stability, subsystem compatibility, line filter considerations, and system design/integration for predictable/programmable performance.

The second edition of the book extends the scope of the first edition to the emerging topic of Dc Power Distribution Systems . Starting from the converter circuit analyses, small‐signal modeling and dynamic analyses, and control designs for standalone dc‐to‐dc converters, the book culminates with Four New Chapters about Dc Power Distribution Systems , covering the system stability, subsystem compatibility, line filter considerations, and system design/integration for predictable/programmable performance.

The second edition of the book extends the scope of the first edition to the emerging topic of Dc Power Distribution Systems . Starting from the converter circuit analyses, small‐signal modeling and dynamic analyses, and control designs for standalone dc‐to‐dc converters, the book culminates with Four New Chapters about Dc Power Distribution Systems , covering the system stability, subsystem compatibility, line filter considerations, and system design/integration for predictable/programmable performance.

This paper presents a non-codebook based Multiple User Multiple Input Multiple Output (MU-MIMO) test-bed system for Time Division Duplex (TDD) Long Term Evolution-Advanced (LTE-A). The system was i...

This paper proposes a new load impedance specification for multistage dc power conversion systems. The proposed specification avoids drawbacks of the existing specifications, such as the lack of explicit connections to the dc-link dynamics and the unnecessary conservativeness. The new specification offers a direct command/supervision of the frequency- and time-domain dynamics of the intermediate dc link, while being less conservative than the existing specifications. This paper also presents procedures for redesigning ill-conditioned load impedances to comply with the specification. The validity and utility of the proposed specification are demonstrated using an experimental two-stage dc power conversion system.

This paper presents a new design approach to the type 3 compensator for voltage-mode controlled (VMC) buck converter for good closed-loop performance over a wide input voltage and load current range. The new design method offers superior load and line transient responses to the existing methods, such as K factor method and computer-aided iterative technique. A design example is presented to show the superiority of the proposed design technique to the existing designing techniques. The effectiveness of proposed design technique is verified using PSpice and PSIM time-domain simulations.

In this paper, we propose a new design method for multistage dc power distribution systems, which employ several pulsewidth modulated (PWM) converter stages and intermediate line filters in a cascaded manner. In the proposed method, individual PWM converter stages are initially built as a standalone converter, powered from an ideal voltage source and loaded with a current sink. Once the individual PWM converters are properly engineered based on the standard procedures, the intermediate filters are then designed and fabricated to provide the desired converter performance, dc link dynamics, system stability, and system dynamics. Thus, the task of designing a dc power distribution systems is reduced to the design problem of intermediate line filters. The validity of the proposed method is confirmed with an experimental dc power distribution system.

This paper investigates the impacts of the load subsystem on stability and performance of the upstream converter in multistage Dc-to-Dc power conversion systems. This paper demonstrates that an appropriate load subsystem can be constructed to provide both stability and intended performance for the upstream converter at the brink of instability before being coupled with the load subsystem. These stabilizing effects of the load subsystem are theoretically analyzed and experimentally validated using a two-stage power conversion system, consisting of an upstream boost converter, downstream buck converter, and two filter stages. This paper also presents the design procedures for the stabilizing load subsystem, along with the performance verification of the upstream boost converter and the downstream buck converter.

In this paper, an isolated double step-down dc–dc converter with high efficiency and high step-down function is proposed. The proposed converter employs an additional capacitor in the primary side. Compared to the conventional full-bridge converters, the proposed converter has a double step-down feature with reduced voltage stress at the primary side of the transformer. Moreover, voltage stress of three primary-side switches reduces to half of the input voltage and zero voltage switching (ZVS) is naturally achieved for all switches with lower output capacitor energy of the switches. Therefore, the proposed converter requires smaller leakage inductance than the conventional full-bridge converter. Without adding complexity to the hardware and control, the proposed converter inherently prevents transformer saturation problem caused by the dc component of the transformer. A 3-kW experimental prototype is constructed to verify the performance of the proposed converter.

The input impedances of pulse width modulated (PWM) dc-to-dc converters, which dictate the outcomes of the dynamic interaction between dc-to-dc converters and their source subsystem, are analyzed in a general and unified manner. The input impedances of three basic PWM dc-to-dc converters are derived with both voltage mode control and current mode control. This paper presents the analytical expressions of the 24 input impedances of three basic PWM dc-to-dc converters with the two different control schemes in a factorized time-constant form. It also provides a comprehensive reference for future dynamic interaction analyses requiring knowledge of the converters’ input impedances. The theoretical predictions of the paper are all supported by measurements on prototype dc-to-dc converters. The use of the presented results is demonstrated via a practical application example, which analyzes the small-signal dynamics of an input-filter coupled current-mode controlled buck converter. This elucidates the theoretical background for the previously-reported eccentric behavior of the converter.

The output impedances of pulse width modulated (PWM)dc-to-dc converters, which dictate the outcomes of the dynamic interaction between dc-to-dc converters and their load subsystem, are analyzed in a general and unified manner. This paper presents the analytical expressions of the output impedances of three basic PWM dc-to-dc converters operating with current mode control. It also provides a comprehensive reference for future dynamic interaction analyses requiring knowledge of the converters output impedances. The theoretical predictions are all supported by measurements on prototype dc-to-dc converters. The use of the presented results is demonstrated via practical application examples, which deals with current-mode controlled buck and boost converters connected with practical load subsystems.

This paper investigates the loading effects on the input impedance of the upstream converter stage in multistage dc power distribution systems. The paper shows that the loading effects depend on the topology of the converter stage. The loading effects are not observable in the input impedance of the buck converter. On the other hand, the loading effects are apparent in the input impedances of the boost and buck/boost converters. The outcomes of the paper can be used to analyze the stability of the whole power system. Theoretical results are all validated by both PSpice and PSIM time-domain simulations.

This study presents the design and performance evaluation of the digital control adapted to an LLC series resonant dc-to-dc converter operating with wide input and load variations. The proposed control design correctly incorporates the wide-varying power stage dynamics and variable small-signal gain of a digitally controlled oscillator, thereby offering satisfactory converter performance for all the operational conditions. The proposed digital controller adopts the push–pull mode control scheme, which executes the control action two times in one switching period, to minimise the time delay and enhance the performance. Using a 150 W experimental converter, the performance of the proposed push–pull mode digital control is demonstrated in comparison with that of the conventional complementary mode digital control, which performs the control action only once in one switching period.

This paper presents a new design technique for multi-stage dc power distribution systems, which consistently offers the pre-programmed performance for dc distribution bus, irrespective of detrimental interactions among subsystem components. The paper demonstrates that the proposed design technique provides the aimed performance, even for cases in which the conventional design encounters instability due to adverse interactions from an ill-conditioned source subsystem. The performance of the proposed technique is theoretically validated and experimentally supported using a prototype two-stage dc power distribution system.

This paper proposes a new load impedance specification for multi-stage dc power conversion systems. The proposed specification avoids drawbacks of the existing specifications, such as the lack of explicit connections to the dc link dynamics and unnecessary conservativeness. The proposed specification offers a direct command/supervision of the frequency- and time-domain dynamics of the intermediate dc link, while being less conservative than the existing specifications. This paper also presents procedures of redesigning ill-conditioned load impedances to comply with the specification. The validity and utility of the proposed specification are demonstrated using an illustrative example.

An average current mode control scheme that consistently offers good dynamic performance for LLC series resonant DC-to-DC converters irrespective of the changes in the operational conditions is presented in this paper. The proposed control scheme employs current feedback from the resonant tank circuit through an integrator-type compensation amplifier to improve the dynamic performance and enhance the noise immunity and reliability of the feedback controller. Design guidelines are provided for both current feedback and voltage feedback compensation. The performance of the new control scheme is demonstrated through an experimental 150 W converter operating with 340 V to 390 V input voltage to provide a 24 V output voltage.

In this paper, an improved non-isolated 3-level high step-up boost converter is proposed. By using the well known duality principle, the proposed converter is derived from two-phase buck converter. Compared with the traditional boost converter and 3-level boost converter, the proposed converter can obtain very high voltage conversion ratio and the voltage stress of switching devices and diodes is only 1/4 of the output voltage. A 1 kW prototype converter is built and tested to verify performances of the proposed converter.

In this paper, a non-isolated high step-up and high efficiency boost converter is proposed. By using the 3-level boost converter structure, the proposed converter can obtain higher voltage gain than conventional high step-up converters. The voltage spike of the switching device is well clamped by using the clamp circuit composed of a clamp diode and a capacitor and the energy of the leakage inductor of coupled inductor is effectively transferred to output. Due to the 3-level structure, the equivalent switching frequency of the coupled inductor is doubled, which results in reduced inductor size. A 500 W prototype converter is built and tested to verify performance of the proposed converter.

A new sustain driving circuit, featuring an energy-recovering function with simple structure and minimal component count, is proposed as a cost-effective solution for driving plasma display panels during the sustaining period. Compared with existing solutions, the proposed circuit reduces the number of semiconductor switches and reactive circuit components without compromising the circuit performance and gas-discharging characteristics. In addition, the proposed circuit utilizes the harness wire as an inductive circuit component, thereby further simplifying the circuit structure. The performance of the proposed circuit is confirmed with a 42-inch plasma display panel.

This paper presents the performance evaluation of an interleaved boundary conduction mode (BCM) boost power factor correction (PFC) converter employing three different switching devices: the super junction silicon (Si) MOSFET, silicon carbide (SiC) MOSFET, and gallium nitride (GaN) high electron mobility transistor (HEMT). An experimental 500 W interleaved BCM boost PFC converters is built and its performance is evaluated while adopting each of the three semiconductor devices as the main switch. The overall efficiency and thermal performance of the experimental boost PFC converter are analyzed under three different operational conditions: one operational condition with the baseline switching frequency of fs base = 65 kHz and the other two conditions with fs base = 130 kHz and 200 kHz. The three baseline frequencies are selected in consideration of IEC 61000-3-2 and CISRR 22 EMC standards for conducted emission noise. This study confirms that the GaN HEMT exhibits the superior switching characteristics and pronounces its merits at high frequency operations. The current paper highlights the efficiency improvement with the GaN HEMT and demonstrates its application potentials to high power density/low profile BCM boost PFC converters.

Three different current-mode control schemes, peak current-mode control, charge control, and average current-mode control, are investigated for application to asymmetrically driven bridge-type pulsewidth modulated dc-to-dc converters. The principles, implementation, and performance of the three control schemes are compared in an attempt to identify their respective merits and limitations. Design considerations for feedback compensations are also given for the three control schemes. The theoretical predictions of this paper are supported by both experimental results and computer simulations.

This paper presents the theoretical and practical details involved with the small-signal analysis of switching power converters under a strong influence of input filter interaction. A boost dc-to-dc converter controlled by voltage-mode control and the same boost converter controlled by current-mode control are used as illustrative examples. The theoretical predictions of this paper are supported by experimental results and computer simulations

This paper investigates stability of dc-to-dc converters deriving another dc-to-dc converter through a filter stage. The impacts of the downstream filter/converter stage on the absolute and relative stabilities of the upstream converter are analyzed. The absolute stability is examined using the minor loop gain, defined as the ratio of the impedances seen at the output port of the upstream converter. The relative stability is assessed using the loop gain expression of the upstream converter. This paper reveals that the downstream filter/converter stage rarely destabilizes the upstream converter, but usually dictates the loop gain characteristics of the upstream converter and frequently determines the phase margin and 0 dB crossover frequency of the loop gain. This paper proposes a simple method to determine the stability margins of the converter from the minor loop gain. The theoretical predictions are supported by both small-signal simulations and experimental measurements.

The two prevalent s-domain models for current-mode control, the continuous-time model and the unified model, exhibit noticeable differences in their small-signal predictions and therefore have become the subject of comparisons and clarifications. The current letter presents an alternative way of deriving the unified model, thereby providing an additional guide for assessing the validity of the unified model. This letter also presents experimental data that support the accuracy of the unified model.

This paper paper presents the practical details involved in the design and implementation of a contactless battery charger that employs a pair of neighboring printed circuit board (PCB) windings as a contactless energy transfer device. A prototype contactless battery charger developed for application with cellular phones is used as an example to address the design considerations for the PCB windings and energy transfer circuit, plus demonstrates the performance of the contactless charger adapted to a practical application system.

Blind beamforming based on the maximum signal-to-noise ratio (MSNR) can improve the performance of an array system only when the processing gain of the given code-division multiple-access (CDMA) system is high enough such that the desired signal can become dominant after despreading (see Choi, S. and Shim, D., IEEE Trans. Veh. Technol., vol.49, p.1793-1806, 2000; Choi, S. and Yun, D., IEEE Trans. Antennas Propagat., vol.45, p.1393-1404, 1997). We consider a maximum signal-to-interference-plus-noise ratio (MSINR) beamforming. The MSINR performance criterion is chosen to deal with strong interferers effectively. It is shown that blind MSINR beamforming is possible by directly utilizing the input and output signals of correlators of the CDMA systems. In addition, we propose an adaptive beamforming algorithm at a lower computational complexity - about O(7.5N) - where N is the number of antenna elements of the array system. Simulation results are presented in various signal environments to show the performance of the proposed adaptive algorithm.

This paper presents a method for designing the control loop for DC-to-DC power converters when uncertainties exist in the AC characteristics of the converter's load. In the proposed method, a converter is initially considered as a stand-alone module feeding a current sink load and the control loop of the converter is then designed in a way that maximizes the robustness of the converter's closed-loop performance against the unknown AC dynamics of a potential load. As a result, the proposed control design method can provide the predictable closed-loop performance for a converter when it is loaded with an actual load whose AC characteristics are unknown in advance.

This paper presents the design and performance evaluation of the digital control adapted to an LLC series resonant dc-to-dc converter operating with wide input and load variations. The main theme of this paper is to highlight the advantage of using the push-pull mode of digital pulse width modulation (DPWM) operation over the complementary mode operation for the implementation of digital control to the resonant converters using a low cost digital signal controller (DSC). Conventionally, the complementary mode of DPWM operation is used for resonant converter. However, the push-pull mode of DPWM operation is chosen for the resonant converter circuit to improve closed-loop performance. Design procedures and performance evaluation are illustrated for both DPWM operational modes using an experimental 150 W LLC converter.