There is, I think, something ethereal about i —the square root of minus one. I remember first hearing about it at school. It seemed an odd beast at that time—an intruder hovering on the edge of reality.

Usually familiarity dulls this sense of the bizarre, but in the case of i it was the reverse: over the years the sense of its surreal nature intensified. It seemed that it was impossible to write mathematics that described the real world in …

I and i

[신간의 별자리x] 우리/미술, 그리고 ‘슬픔의 박물관’

This paper presents a detailed description of finite control set model predictive control (FCS-MPC) applied to power converters Several key aspects related to this methodology are, in depth, presented and compared with traditional power converter control techniques, such as linear controllers with pulsewidth-modulation-based methods The basic concepts, operating principles, control diagrams, and results are used to provide a comparison between the different control strategies The analysis is performed on a traditional three-phase voltage source inverter, used as a simple and comprehensive reference frame However, additional topologies and power systems are addressed to highlight differences, potentialities, and challenges of FCS-MPC Among the conclusions are the feasibility and great potential of FCS-MPC due to present-day signal-processing capabilities, particularly for power systems with a reduced number of switching states and more complex operating principles, such as matrix converters In addition, the possibility to address different or additional control objectives easily in a single cost function enables a simple, flexible, and improved performance controller for power-conversion systems

Model Predictive Control—A Simple and Powerful Method to Control Power Converters

Predictive control is a very wide class of controllers that have found rather recent application in the control of power converters. Research on this topic has been increased in the last years due to the possibilities of today's microprocessors used for the control. This paper presents the application of different predictive control methods to power electronics and drives. A simple classification of the most important types of predictive control is introduced, and each one of them is explained including some application examples. Predictive control presents several advantages that make it suitable for the control of power converters and drives. The different control schemes and applications presented in this paper illustrate the effectiveness and flexibility of predictive control.

Predictive Control in Power Electronics and Drives

This paper presents a predictive current control method and its application to a voltage source inverter. The method uses a discrete-time model of the system to predict the future value of the load current for all possible voltage vectors generated by the inverter. The voltage vector which minimizes a quality function is selected. The quality function used in this work evaluates the current error at the next sampling time. The performance of the proposed predictive control method is compared with hysteresis and pulsewidth modulation control. The results show that the predictive method controls very effectively the load current and performs very well compared with the classical solutions

Predictive Current Control of a Voltage Source Inverter

Sliding mode control is a robust control method with guaranteed large signal stability and good dynamic response. Despite its advantages, sliding mode control for DC-DC converters suffers from non-zero steady state error and variable switching frequency that depends on the converter parameters. This paper proposes a simple sliding mode like control (SMLC) technique for the buck converter that has a fixed switching frequency and zero steady state error. The response of this controller is robust and can be defined directly in the time domain. In addition, fuzzy logic implementation of the proposed SMLC is provided. Experimental results show that the proposed SMLC has good first-order dynamic performance and no steady state error.

A new sliding mode like control method for buck converter

A conventional single stage ac-dc LED driver usually produces significant twice-line-frequency ripple current when a high power factor is achieved. The ripple current causes a lighting flicker of the LEDs. In this paper, an energy channeling ripple cancellation LED driver is proposed. It achieves true single stage power conversion, maintains a high power factor while significantly removing the twice-line-frequency ripple current - flicker free LED driving. An 8.5 W, 50 V/0.17 A Buck-Boost experimental prototype has been built to verify the proposed method.

Energy Channeling LED Driver Technology to Achieve Flicker-Free Operation With True Single Stage Power Factor Correction

This paper proposes a new current-source driver (CSD) with discontinuous inductor current. Compared to other CSDs proposed in the previous work, the most important advantage of the proposed CSD is the small inductance (typically, 20 nH at 1 MHz switching frequency). This translates into the footprint reduction of as much as 90% compared with the continuous CSDs. Other features of the proposed CSD includes: 1) fast switching speed and reduced switching loss; 2) discontinuous inductor current with low circulating loss; 3) gate energy recovery; and 4) wide range of duty cycle and switching frequency. The experimental results verified the functionality of the proposed CSD. At 12 V input, 1.3 V output, and 1 MHz switching frequency, the new CSD improves the efficiency from 80.7% using a conventional driver to 85.7% at 25 A output, and at 30 A output, from 77.9% to 84.4%.

Discontinuous-Current-Source Drivers for High-Frequency Power MOSFETs

This paper presents a new nonisolated asymmetrical buck voltage regulator module. A transformer is used to extend the extremely low duty cycle of a conventional buck converter. Turn-off losses can be significantly reduced due to the extension of duty cycle, and there are no turn-on losses owing to the zero-voltage turn-on condition. At the same time, the voltage stress over the synchronous rectifier MOSFETs is also reduced. Therefore, the reverse-recovery losses of the body diode can be reduced. Furthermore, the MOSFETs with lower voltage rating and lower RDS(on) can be used to reduce the conduction losses. In order to reduce the turn-off losses above the switching frequency of 1 MHz further, a new current-source driver is also proposed, which is suitable to this new topology. A 12-V input prototype with the switching frequency of 1 MHz was implemented. Simulation and experimental results verify the functionality and benefits of the proposed topology.

A Nonisolated ZVS Asymmetrical Buck Voltage Regulator Module With Direct Energy Transfer

A circuit controls the low frequency load currents drawn by components of telecommunications systems. The circuit includes a power converter, a first sense circuit, a second sense circuit, a comparator, and a power converter control circuit. The power converter control circuit controls the power converter's duty cycle in accordance with the input signal compared to a reference. In this manner, the low frequency load currents may be easily and economically controlled.

Yan-Fei Liu

Papers

A new sliding mode like control method for buck converter

Energy Channeling LED Driver Technology to Achieve Flicker-Free Operation With True Single Stage Power Factor Correction

Discontinuous-Current-Source Drivers for High-Frequency Power MOSFETs

A Nonisolated ZVS Asymmetrical Buck Voltage Regulator Module With Direct Energy Transfer

Apparatus and method of controlling low frequency load currents drawn from a DC source in a telecommunications system